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Inventor Demonstrates Infinitely Variable Transmission
ElectricSteve writes with this excerpt from Gizmag:
"Ready for a bit of a mental mechanical challenge? Try your hand at understanding how the D-Drive works. Steve Durnin's ingenious new gearbox design is infinitely variable — that is, with your motor running at a constant speed, the D-Drive transmission can smoothly transition from top gear all the way through neutral and into reverse. It doesn't need a clutch, it doesn't use any friction drive components, and the power is always transmitted through strong, reliable gear teeth. In fact, it's a potential revolution in transmission technology."
The real icing on the cake is (as mentioned near the end) the secondary drive doesn't require a whole lot of power so it can be run by a flywheel. Infinite torque? Frictionless? This is almost too good to be true, there has to be some catch. Like the primary input drive requires more energy than they expected but I can't see it--although I'm not a mechanical engineer.
... these are the kind of news stories an engineer loves to read about.
This is the kind of thing you like to see -- I hope this man has all the capital he needs and gets that prototype up and running for demonstrations. Plus it's a small time plumber inventor
My work here is dung.
If this gearbox works we could see a massive decrease in fuel consumption and much better power delivery in our cars.
Because right now the gearboxes are rubbish, they haven't evolved much in the last decades.
Love many, trust a few, do harm to none.
Lucky for him ICE cars will probably still be around for the next 20 years. Electric motor cars don't normally need to change gears.
...when can I fit this on my bicycle?
(I'm serious. Proceeding to read TFA...)
.: Max Romantschuk
Right now automatic transmissions make a huge amount of money for auto dealerships and other auto repair companies.
You control the gear ratio by varying the speed at which you spin another axle?
So what drives that crank, and how do you smoothly vary the speed at which it's driven?
The article notes that the motor runs (or can run) at a constant speed, which isn't always the case for gas powered engines, although I'm sure they each have a good zone where they produce power effectively. It seems this type of transmission would be perfect for electric motors which can operate at a full constant level of power right off the line. It still seems like you would want a few power settings; one for heavy traffic, one for the city, one for the highway (at least).
http://www.hawknest.com/
The "transmission ratio is controlled by the relative speed of the motor driven shaft" technique is exactly what's used by the transmission in the Prius (and every other Toyota, Nissan, and Ford hybrid).
Even if there are future refinements and inventions necessary to unlock the full potential, I applaud his highly creative technique.
Well, obviously this is not "frictionless" - it just appears not to use friction as the main force of transmission, like friction-cone type CVTs do. There are other types of CVTs that do not use friction - for example chain-driven CVTs or hydraulic-type CVTs. Theoretical infinite torque is also not exactly new - look at hydristors, for example. I'd love to see more technical detail about what the guy actually invented there, TFA is not exactly helpful when it comes to the inner workings of his gearbox.
Ubi solitudinem faciunt, pacem appellant.
The greatest limitation on today's CVTs is the lack of sufficiently strong materials for the belts. While research and development has already yielded marketable CVTs, they are limited to being paired with relatively low displacement, low horsepower, low torque engines for durability purposes. Your father's Oldsmobile's honkin' huge Rocket V-8 or your cousin Bubba's new pickup truck's V-10 would likely tear any of those CVT belts to shreds. Supposing that this new design is strong enough, those engine pairing limitations could be done away with once and for all.
I deny that I have not avoided attaining the opposite of that which I do not want.
Same ratio for forward and backward driving, meaning you can drive just as fast backwards as you can forward.
yeah... http://www.youtube.com/watch?v=S7ipFApsFec
Several tractors I have owned have hydrostatic transmissions. These are also infinitely variable, but they use a hydraulic pump and motor to achieve it. They provide very high torque and excellent power transmission. I always wondered why they were never used in cars.
I just hope he doesn't sell out to a big car manufacturer who buries it for 30 years because they make more money
with the current system.
I think the weakness in this design is the need to rotate the "bottom" shaft at a speed equal to the input shaft for neutral. While indeed it doesn't need a lot of power, it's a lot of rotation where, in competing designs, a clutch disengages or the drive motor is idling. I could see a lot of things going wrong if the synchronization was imperfect, or if something went wrong.
How do you start this up from a dead stop? Somehow you have to exactly match the shaft rotation speeds to keep it in neutral before you start moving forward, otherwise there will be a lurch.
I look forward to seeing how this is developed further. It has a lot of potential.
While quite elegant, this solution requires power input... So not so great on a bicycle...
And as far as cars go, you have to spin a shaft in order to achieve neutral. Which means that you still need a clutch or something for a car to be safe. (If the engine's running and the electric motor spinning the shaft fails the car will go forward... Not nice.)
(Am I the only one who thought that the TFA's statement that understanding these mechanics is dumbing it down? I think it's simple, honestly. I'm not claiming I would have invented it, but I do understand the principle...)
.: Max Romantschuk
By "frictionless" I assume they're talking about something to do with the clutch, where you have two plates that you can jam against each other to transmit power via friction (and if you take them a little distance apart you they have a little bit of slip to them, so that during a gear change can the engine's speed will be smoothly met by the friction until it matches the drive-shaft's speed without any terrible lurch which would damage everything). This thing still has normal mechanical friction, as any set of gears would, but doesn't have any component explicitly designed for friction.
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I think so. http://en.wikipedia.org/wiki/Limited_slip_differential
On a straight road, both tires spin at the same speed. On a curve, the difference in tire rotation causes the smaller gears in the differential to spin. If those gears were connected to a motor you could choose to spin the tires at a different rate any time.
I'm not convinced that this is as efficient as a normal gear system, since it will take power to spin the second shaft.
IVTs are certainly not new, and have been around since the 30's. The IVT described is actually similar to eCVTs, which are used on Ford & Toyota hybrids (e.g., Toyota's Hybrid Synergy Drive...both of those use gears (without friction elements), and achieve the ratio variation by the relative rotations of the IC engine & electric motor.
Also, it's not wise to use spur gears in automotive transmissions, since those are notoriously noisy; it's far better to use helical gears.
Well, one potential flaw is the eccentrically mounted components. Unless properly counterweighted, at high speed this will cause a lot of vibration.
BTW, couldn't you do this sort of thing with a differential?
When our name is on the back of your car, we're behind you all the way!
An old Volkswagon Bug with this transmission can pull a full weight loaded Semi trailer or flatbed, or locomotive engine. or burn it's tires out trying due lack of the VW bug weighting enough.
That would be the first IVT apart from the one that Torotrak developed years ago, that is.
I must admit, I need to clean up my pants now. This is incredible.
"What is there a tank on the boat? WHY IS THERE A TANK ON THE BOAT?!?" L4D2
I seem to recall that turbines are incredibly efficient when operating at the optimal spin, but have a very narrow range. Sounds like this new gearing would be great for turbines.
Hasn't he just re-invented the differential gear? I can do this with Lego ... Also, the neutral - a "powered neutral"? It won't freewheel then. I reckon you'll still need some sort of clutch to completely disengage the drive shaft from the wheels, else you'll never be able to push the thing with the engine off...
They are actually comparing it to other times of CVTs, which use friction belts driving a pair of cones. Nothing to do with the clutch. The device from TFA uses only gears, in particular a set of planetary gears, so they say that the advantage would be no danger of slippage compared to friction driven CVTs. From what I know, in the usual designs, the slippage problem is not really limiting anyway, though.
Ubi solitudinem faciunt, pacem appellant.
It works as a demo very well I , as an ME agree.
The big issue in science and engineering is ALWAYS reduction to practice. The inventor acknowledges this and is working with an engineering firm to make a practical pseudo-production testing model. When you have no clutches, the lack of shock loading means the size of gears and the housing can be substantially reduced, since there won't be an engine load shock issue. There can be issues of loads when parked, though, when another car bumps yours. The other issue is how do you tow such a car when the engine fails or you want to tow it behind a motor home? There may still need to be a "cog" connection for towing.
Issues involved in getting it into a small, produceable and cost effective prototype will tax the engineers. If they can do it, there will be applications in many different fields.
Given that the gear ration can be set by controlling the small electric motor speed, it can be integrated with other electronic control systems easily.
I have to hand it to the guy for coming up with a very clever implementation. This is why we need to support the math, science and physics departments everywhere, because in the end, the world is a physical place and the countries who prosper the most will be the ones with the most technologically up-to-date innovators.
They finally get shifting gears right just as we switch to electric cars that don't need then.
For every action, there is an equal an opposite reaction. So, when your monster torque motor is spinning the input shaft, surely it is pushing against the counterspinning shafts with exactly that amount of power? In other words - won't the mechanism (electric motor, flywheel, etc.) that keeps the counterspinning shafts running at the desired speed ratios have to overcome this reaction? It's possible that the frictional and mass inertia of the system helps some, but how much?
I'm not an ME, but the explanation of what the required control motor power is relative to input motor power is very thin here. Be very interesting to see what the detailed input / output / control torque & power measurements end up being.
watch the video half way down TFA- it shows in pretty fair detail how the d-drive transmission works.
In the vid the inventor doesn't really say "infinite torque" - just that the torque is dependent on the size of the gears - which is technically correct. Although gears 50 feet across will not be used on automobiles, they might on ships. And such gears will handle a lot more torque.
Seven puppies were harmed during the making of this post.
I noticed the problem with that little "show" - the back side has some things that are being kept hidden. Whats on the back side? Variable speed electric motors that are being used to spin those two shafts.
'course, that's why any sane vehicle owner drives stick...
It is a very interesting approach, the problem that may happen (I don't know, just guessing here) is to locking the lower shaft while trying to go full force, isn't the entire premise of friction basically shifted (sorry for the pun) to the device that will stop or let go of the lower shaft, which needs to be stopped for the torque to be transmitted to the wheels for example? So there are these 2 small black gears if you look at the video, these gears are perpendicular to the lower shaft, sitting on it sideways, is that the one that will be locking the shaft or driving it, because then all of that power difference (either goes to the wheels or goes to the shaft) will be at a point of failure right there, how will they stop and start that one, is there a reliance on the electrical motor there to hold against the driving shaft? If there is, then the electrical motor will have to produce as much power and torque as the main driving engine.
But I maybe wrong completely and just misunderstood this thing totally.
You can't handle the truth.
In a normal transmission speed and torque and changed by the gears. How does this work here? You need a variable speed motor to for the gearbox. So what are the power, torque and speed requirements for this extra motor? If you want to drive really slow but with a lot of torque (accelerating from a stop uphill) does this still work with a small variable speed motor?
Without any measurements/calculations on the efficiency this does not sound like the future of transmissions.
Yeah, thanks - I missed that video. I am slightly too hungover to wrap my head around a video demonstration at the moment, though... Gotta have a look if his patent is already published later.
Ubi solitudinem faciunt, pacem appellant.
Hmm I don't see anywhere whether it allows reverse power input: that is the wheels driving the power train.
That's what's keeping the nifty robotics gearboxes (with high and efficient one step ratios) being used in automotive applications: if you did, and you'd run out of fuel or power, the powered wheels would block (ok for a robot, not for a car).
IANAME, but what concerns me over this demonstration is that I do not see any work being generated by the output of this device. All the energy put into the system (from the main and secondary motors) seems to do is to spin an unconnected output shaft - so in effect the practical efficiency of the demo unit is zero.
My gut feeling is that spinning the secondary motor when loading the primary motor is going to take a lot more energy than is implied in the TFA and TFV.
Can anyone enlighten me as to why I am wrong?
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i.e. most people outside of North America
For all intensive porpoises your a bunch of rediculous loosers
Slippage limits torque. the whole advantage of this system is that it allows infinitely variable output - from full speed reverse through neutral, to full speed forward, all with full torque limited only by the size of the toothed gears used. All power transmission in this device happens through toothed gears. There are no belts, friction plates, clutches, etc - all toothed gears and only toothed gears, with zero slippage, full torque, and infinitely variable output .
At first blush, I'd say that both Toyota and John Deere have already produced something similar. What he appears to have, however, is a system that can smoothly transition (with power) through neutral and reverse. That indeed could be the cool, patented part, as the rest of his transmission is pretty well understood and actually in production already in many of the applications they list for their invention. I don't see any patent application listed, so I can't tell for sure exactly where his breakthrough is.
Here's the fundamental principle by which his transmission works, though: Basically the idea is you supply driving power to a planetary gear system and then use another variable system such as an electronic motor or, in John Deere's case, a hydraulic motor, to take speed (but not power) away from the output shaft by spinning part of the planetary system. If you understand how a planetary gearbox works, this makes sense. So in John Deere's case, the less-efficient hydraulic motor uses a tiny amount of power to control how the actual, geared, power is transmitted to the wheels. Using this system JD has a completely variable system with a particular gear range (this is a tractor after all) that has a powered neutral stop. In the pictures and video you'll note he has two electric motors that control the ratio.
Toyota does something similar with their hybrids, although it's more of a way to efficiently (and brilliantly, I might add) blend the gasoline motor's power with the electric system in an infinitely variable way.
Another way of implementing an IVT, though I don't think it is as efficient, is to use a differential. Power comes in the normal part of the differential (IE spinning the entire gear assembly), and then power comes out one side, and an electric or hydraulic motor attached to the other side (Where the wheels would normally go). You can then use the motor to change the apparent gear ratio, and even reverse it.
Are you aware that should americans switch to manual gears they would save between 20% and 30% in car's fuel? Think how much are you spending on hybrid technology and such and how a switch to simpler technology could save so much. Do greens drive manual gear cars? I don't think so.
The catch behind this transmission is that it needs two power inputs: one to spin the "idler" shaft and one that eventually gets passed through the whole thing. If his idler shaft stops moving at neutral (ie power failure), then the car will get thrown into gear and start moving, so a clutch will be needed somewhere anyway.
I doubt the idler shaft requires a lot of energy, and so it shouldn't hurt efficiency that much. The gains you get by using this transmission are probably greater than the losses, assuming you don't let your car idle a lot, which you shouldn't anyway.
Turbine without regeneration cycle have approx 30% efficiency and can up 40% efficiency if hot exhaust is returned into the cycle (regeneration). Diesel piston engines actually achieve between 40% and 45% efficiency at optimal constant speed. If you consider turbine systems at optimum efficiency with regeneration and high operating speed are quite large, noisy and need tight maintenance cycles for the finely adjusted and physically resistant blades, this is not suitable for small vehicles. By the way this new gearbox design would be very suited to diesel engines.
Léa Gris
Yeah, but that's basically the working principle of any planetary gear system. If you don't hold any of the components locked in a planetary gear, you can configure the output to be proportional to the ration of the inputs. Combine a CVT with a planetary, and you get an infinitely variable transmission. That's used in hybrid vehicles all the time, and doable with gears only, not using friction components. From quickly skimming over the video, I definitely see a planetary gear setup there. As I said above, I'd love to see more technical detail on that one, TFA does not really make clear what is actually new about this.
Ubi solitudinem faciunt, pacem appellant.
If he really had something here that could be so wonderous. Why not try to interest a car manufacturer in licencing to the technology. Instead he says he is "raising money for a prototype", sounds like an investment scam. Ive heard it said there is not anything particularly new about this design, that he basically has taken a design that already exists and labelled it as his own.
Would a gearbox still be needed anyway if and when pure electric/battery powered vehicles become the norm? If not, then this invention is great, but a bit late.
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Anyone who knows how a Prius HSD works will see that this is largely the same thing.
Prius uses Sun and Planetary gears with primary from gas engine and EV motors driving other shafts that vary the power from sources.
No clutches, no fixed ratios. Everything is controlled by the speed of the EV controlling motors.
cvt. 'nuff said.
Wealth is the gift that keeps on giving.
I think Toyota already invented this with their Prius hybrid car. It uses a traditional planetary gear, but in addition to the gasoline engine and the wheels, it's also tied to an electric motor. The electric motor spins as different rates (or not at all), thereby choosing an infinite number of engine-to-wheel ratios.
Meanwhile:
I have a VW Beetle with 6 gears automatic. Obviously that's not a CVT, but the huge number of gears keeps my engine hovering at 2000 rpm consistently (between 10 and 60 mph), so it has the same effect as a CVT (keeps the engine at the most efficient spot).
"I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
I'm no engineer either, but AFAICS the two counter-rotating shafts share the load between them, and the forward/reverse motion is the difference of the two.
So if one shaft is strong enough to transmit full torque from input to output, there's no problem if you split it between them because the load will always be less than full-power in either direction.
"Slow down, Cowboy! It has been 3 years, 7 months and 26 days since you last successfully posted a comment."
That's how the system works. The idea is that however the mechanics work, there is no real load being placed on that lower control shaft, and the secondary motor only need to be strong enough to overcome the friction of the bearings on the sun gear. How well that works in reality, I'm not certain.
Hey now, there are some of us in North America who prefer to drive manual transmissions.
Serious? Seriousness is well above my pay grade.
That is, Toyota's system. Also this same system is used by BMW for their variable ratio steering system.
http://lkml.org/lkml/2005/8/20/95
My automatic in my last car lasted 340,000 miles and never needed service. In contrast doesn't a manual need a clutch replacement every 100,000 miles due to wear during shifting? So that means, at least in my experience, the manual costs more.
"I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
There's nothing new here, except for the fact that this gentleman has attached some additional rods to a planetary gear system.
And no, the Prius does not use a belt cvt as folks seem to think it does.
http://eahart.com/prius/psd/
My connection is too slow for video, so I have not looked at the thing, but I have seen your criticism raised elsewhere.
Other people have mentioned that the test does not show any load, I expect that, were it truly a breakthrough, they would go ahead and show it doing some ridiculous things (hey, why not?).
Nerd rage is the funniest rage.
It is indeed similar to the planetary gear coupling boxes in parallel hybrids. And yeah, you are basically right - a 6-gear box holds you sufficiently close to the optimum rpm anyway for practical use. CVTs really shine in heavy machinery, but are not that important for personal cars. Still nice technology, though. To hell with practical importance - all hail those engineering efforts done for the heck of it!
Ubi solitudinem faciunt, pacem appellant.
The Thompson coupling was invented not long ago, and I remember being amazed that there was anything new to be done in the area of mechanical power transmission. And now this. Are we all done now, or is there more still?
Fuck the system? Nah, you might catch something.
Hate to reply to my own post, but here is a fairly detailed explanation of John Deere's IVT: http://salesmanual.deere.com/sales/salesmanual/en_NA/tractors/2006/feature/transmissions/8030_option_code_1127_1137_ivt_trans.html . The relevant part is "The John Deere IVT uses a hydromechanical, power-splitting design where a portion of the power is transmitted mechanically and a portion hydrostatically. A hydromechanical transmission is more efficient than a purely hydrostatic transmission because gears carry power more efficiently than a hydraulic pump and motor. By careful selection of the gearing, the John Deere IVT carries a maximum of the power mechanically both at normal field working speeds and at transport speeds, taking maximum advantage of the higher mechanical efficiency while providing the control and versatility of a hydrostatic." And of course this power-splitting is done via a planetary gear system.
I say this not to take away from the D-Drive's awesomeness (John Deere doesn't do reverse without shifting a gear), but to help offer explanations of how it actually works.
I see a lot of people have chimed in without knowledge of how the Prius HSD works. There is NO conventional belt CVT in a Prius.
Prius works almost exactly like this demo. Gear Driven Planetary and Sun gears.
The HSD with its robust gear system without friction drive is what makes it so special.
Here is a simplified demo of how the Prius HSD works:
http://eahart.com/prius/psd/
it looks cool and promising but is it "true" neutral as in traditional cars where the "input" side is not contributing power but the "output" side is free to spin and not "contribute" power back in?
It would have been cool to see the same demo with a "load" on the output side...perhaps just a heavy disc so once you got the thing up to full speed, the disc would act like inertia and keep spinning even if the D-Drive was in neutral (aka...what you'd have to do if your Toy*ta has a "sticky acceleration" and you need to pop it into neutral)
I watched with interest through 3/4 of the video as they continuously refused to show the back side of the model, just loosely discussing the "control shafts" and couldn't get it out of my mind
"pay no attention to the man behind the curtain".
Then finally at the end they showed the back and surprise, there's another motor there, but trying to explain it off that this motor requires far less energy than you're going to gain by using the rest of the system. Maybe this is true, but that's a poor way to present the design, by hiding a serious concern until the last second.
As they wrapped up the video they did admit that this little kink is going to be the determining factor in whether or not it's a useful design. "Why can't they just tap some of the power off the input shaft to manage the control rods?" I thought. Then it occurred to me, the speed would need to be continuously variable, and that's the whole problem they're trying to solve. So, what we have here is a continuously variable mechanism, so long as we can already provide a continuously variable mechanism. (all his D-Drive needs to complete it is, another D-Drive, which would of course need another D-Drive....) Sounds terribly recursive to me. But he didn't go into any detail as to the requirements of this control system, but from what I can tell, it needs to be continuously variable also. He dismissed it as being easy to achieve with something such as an electric motor, which one could argue the same is true of his entire invention...
We'll see. I'll remain skeptical until his design is complete, including the nagging little details of running the control shafts. But really it's an excellent idea even with this problem. It's solved the larger portion of the problem. One other thing that also came to mind is balance. The orbital gears could really get whipping around the sun gear, they'll have to be balanced. Using orbital gears itself at high torque will create new problems also. I'm no mechanical engineer but I also see a potential problem there with torque on the position of the planetary gears since the shaft isn't fixed. You don't usually see floating gears in transmissions.
I work for the Department of Redundancy Department.
We tried this on a the Freestyle and Five Hundred (Taurus) a few years ago then dropped it because people didn't like the separation in engine sound vs vehicle speed. It had a spooky feel when driving that they never could get used to. A great idea but too different for the masses.
Yes, but by those around us we aren't exactly considered sane.
The new aspect is that this planetary gearset actually has TWO inputs, and the output is determined by the *difference* in speeds between the two. That's how it can go from reverse to forward seamlessly. V1 > V2 is Forward, V1 V2 is Reverse, V1 = V2 is Neutral. Assuming there are no practical limits on the velocity of either input, the possible difference between them is infinite.
Personally I find this really exciting, because i've always been in love with the idea of a variable transmission. Ignoring electric motors for a minute, there are some absolutely INSANE things you can do to a small motor with cams, turbocharging, etc, to extract absolutely massive amounts of power from teeny engines. Like, 1000+hp from sub 2 litre motors. The problem is they end up being extremely peaky (power is only made at a narrow RPM band, or a terribly high one)... but with a variable transmission you can let the engine hunker down in it's sweet spot and let the tranny worry about all the fiddly bits. Hell, you can even do the same thing with a big engine... I wonder if its possible to make five figures of power from a 7 litre? With this we just might find out.
The secondary shaft needs to be driven by something powerful enough to drive the load in reverse.
The primary input's gear is fixed, so the secondary is doing all the work.
Also, in this configuration the main input is not running, therefore the secondary input would have to be using stored energy, or be another engine.
Still very interesting, looking forward to seeing the dyno results.
Yeah. Why would anyone drive a stick when it means they can't talk on their cell phone, put on their makeup and stuff a big mac into their faces at the same time? Sheesh. ...and before anyone says it, yes, I have seen people talk on their phones or eat or put makeup on while driving a stick. Just not all three at once.
This is pretty much exactly what's in every Prius. Little electric motor driving the sun wheel, IIRC in my 2nd gen Prius it's a 9kW motor doing up to 10000rpm in both directions. Transitions from forward to backward speed seemlessly.
Very cool tech, but hardly new.
Yes, the control needs to be continuously variable, but I think that a stack of D-Drives would reduce the torque required by the control system for power control of the final drivetrain, by their reduction, to the point where a relatively small electric motor could do the job.
Although they may not officially encourage this kind of use, the Toyota Prius smoothly goes from forward to zero and reverse drive: Just throw the car into REVERSE while powering it forward. I've tried this up to about 10pmh or so,and it runs its planetary-gear setup through the motions like silk. I haven't had the nerve to do this at higher speeds. BTW, going into PARK while moving at highway speed just causes a motor-controlled slow down followed by neutral. This may be the easiest way to get around the "stuck-accelerator" problem (which I have experienced, very scary indeed).
BTW, couldn't you do this sort of thing with a differential?
Yes. That's basically what the Prius does: it uses a differential (actually an epicyclic, which is a flattened differential) as a mixer, and drives one input with a gas engine and the other with an electric motor, giving not only an infinite number of speeds but also a way to use the engine to charge the motor with excess power, or use the motor for braking. But then you need both an engine and a motor. Managing an infinite drive from a single input is pretty cool.
Nostalgia's not what it used to be.
All through the explanation I was thinking "He just put a motor on a diff? Why didn't I think of that!". But I didn't, and he did, so kudos to him.
Mod parent up.
It seems like this is just an ordinary differential http://en.wikipedia.org/wiki/Differential_(mechanical_device) powered from the wheel side. It will only be able to transmit as much torque as the control motor can produce.
"The new aspect is that this planetary gearset actually has TWO inputs, and the output is determined by the *difference* in speeds between the two."
Sounds like a differential run in reverse.
Seems like a simple demo of what can be done with planetary gears. No calculation of what happens when significant resistance is added (as in when the wheels are touching the ground).
So, rather than show axles rotating without resistance, show us a working transmission under load.
Interestingly, my magic word is "cycloid".
Can you elaborate? You say "combine a CVT with a planetary...not using friction components" but I was under the impression that a standard CVT (with 2 cones and a belt? That's the kind I know about) does use friction components, whereas this new design doesn't.
What I don't get is how exactly this is distinct from a differential gear.
That second engine to run the second shaft is big trouble. It can be weak or even a flywheel? Ok, I'm game. The problem:
That second engine need to be... Fully variable. So in theory, the second engine needs a gear box to change its speed.
oops.
His stuff basically allows the use of a large and powerful engine with the gearing ability of a smaller different one.
He doesn't say what is the power ratio between the two engine. And doing this with a single engine has to be tricky and require a gear box for the second shaft.
I don't like the fact that "neutral" involves having both shafts running at full speed.
my 2 cents worth.
One point that is made is that you don't need a lot of power on the control shaft. Well, frankly, I don't see that... it looks to me as though, in a load situation, the power to turn the planetary gear and thus the output shaft would have to come equally from the sun gear and the ring gear.
Looking at the video, I see there is an anchor plate for the drive motor on the left, which uses an eccentric post to drive something on a second plate; that something results in the two shafts that go through empty space to the third, output plate. We never got much of a look at what was on the second plate. If this is going to have any chance at working, there would have to be some sort of dynamic load balance on that second plate.
The proof, not seen in this video, would be to decouple the drive motor from the control shaft, which would theoretically stop the control shaft from moving and put the thing in full speed forwards. Then load the output by trying to stop it. If the control shaft starts spinning, you don't have a useful product.
FAIL!
Not at 'first post', but at 'troll'.
You couldn't flame your way out of a paper bag, you lying sack of SHIT!
Oh, wait.....
I agree with others about the eccentricity causing vibration, but as it CAN handle torque, you could put a fixed-ratio gear-set either side to convert it down to low-rev high-torque?
Also which axle in the middle handles the power transfer? Surely an axle carrying the output power of a 300bhp engine is not gonna be easy to change the speed of (in order to change the ratio)?
There was a tank out there that used a similar system to transmit the turbine (engine) power to the tracks and allow differentiation between the left and right tracks.
Done in the sixties by a Dutch automobile manufacturer: DAF. First car which could drive as fast forward as backward.
A standard dry clutch on a stick shift wears faster than a stacked wet clutch in an automatic transmission with a torque converter. Show me a dry clutch as used on most cars that outlasts an automatic transmission.
http://www.wind.sannet.ne.jp/m_matsu/prius/ThsSimu/index_i18n.html
Neat-o, and works fine with IcedTea!
Slider controls for accelerator and brake with 'PRNDB' selector, plus individual sliders for motor, engine, and generator and a visual representation of the work/relation of each..
Fun!
'D-Drive' The New Inventors (Australia) Video
There used to be a Dutch car maker DAF They got taken over by Volvo. . Made small cars with CVT since the 70's or before.
Actually, the transmission in the Prius is completely different from this. The Prius takes two full power inputs (the engine and the electric motor), and adjusts the power output from the two (balancing them) to achieve the end ratio. This takes a single full power input (and two factional inputs, perhaps a very small fraction if friction losses are small enough), and produces a variable end ratio. Quite a big difference between them. For the Prius transmission to work, both engines need to be of comparable power (A 100 hp gas engine would need somewhere near a 100hp electric motor). This would likely work with a 100hp engine and a pair of 1/2 hp (or less, depending on precision and friction) electric motors.
And FYI, an OTTO cycle engine is not most efficient at 2000 rpm. It's most efficient at its horse power peak RPM, and at full throttle. Anything less than that (RPM or throttle), and you lose volumetric efficiency. And when I say efficient, I'm saying the power/fuel use is the maximum. It's all about the intake and exhaust design (you can tune them for maximum efficiency at a particular RPM for a particular engine design). That's why hybrids typically use smaller engines. So that you can run it closer to its peak power for longer (40hp at full throttle would be plenty to cruise on the highway and still be able to charge the batteries without needing to be throttled back).
If a man isn't willing to take some risk for his opinions, either his opinions are no good or he's no good
This guy, bless him, may be clever about mechanical things, but he knows nothing about marketing. What he should be doing instead of trying to get money for building a practical test system is telling everyone that he has found the solution to "man-made global warming". Then, after politicians and fools with extra cash throw money at him, he can move to the Cayman Islands and live out his life in luxury.
As everyone has noticed, this is a differential gear. It can't be used as a variable transmission, no sense in pretending you can get around basic laws of physics, no change in torque without varying the leverage, it will never work, forget about it, case closed, good bye.
Does it have the proper amount of SUCTION? /Dyson
This is very cool. Like a valve or transistor, it allows a small control signal (the small control motor) to meter what you get from the big stiff motor. The fact that it goes into reverse is gravy.
this is incorrect, my family's last manual transmission car went over 300,000 miles before we gave it away, and the clutch never once showed any hint of trouble. replaced the timing belt twice, but the clutch was in fine shape.
I've decided to Diversify my Holdings. I've divided my cash between my left and right pockets, instead of all in one.
The new aspect is that this planetary gearset actually has TWO inputs, and the output is determined by the *difference* in speeds between the two.
You just stated the definition of a differential gear. It is not new in any way, and describes exactly how a planetary gear works and is normally used. For a real world example take a look at the Hybrid Synergy Drive used in Toyota Prius. It has precisely that: A planetary gear with two inputs summing up to one output, allowing the engine to operate at optimal rpm regardless of wheel speed.
Take a look at page 10 and 11 of this link. It's the Hybrid Synergy drive "power split device".
http://www.toyota.co.jp/en/tech/environment/ths2/SpecialReports_12.pdf
See the planetary setup on page 10 with an engine (power input) on one side and an electric motor on the other "input" and the output comes out the side (ring gear).
The power from the engine (carrier) is split between the generator (sun) and the motor/output (ring gear) and this ratio is continuously variable.
Toyota's system is slightly different in that the motor is at the output shaft, there is no control over the "third shaft", but the motor could easily have been put there instead.
In BMW's power steering:
http://www.usautoparts.net/bmw/technology/afs.htm
The motor is on the "third shaft". Your steering input is at a fixed rate (let's say) and by BMW turning their DC motor (third shaft) of the planetary set, it alters the output shaft speed. If they turn it the same way you are turning, it adds to the output, it makes the steering quicker, if they spin it the other way it slows it (but increases torque).
Frankly, I'm sure there are more examples outside cars.
http://lkml.org/lkml/2005/8/20/95
Not to worry about 'infinite' or 'frictionless' - these characterizations are not the intent of the device so we can just evaluate it as a normal continuous transmission being controlled by the ratio of speeds between a control shaft and the drive shaft. Efficiency for low-torque cases can be quite decent as eccentric bearings, gear-qualities and diameters can be controlled well with current techniques.
So... with a real torque, there will definitely be significant forces between the two shafts. Clearly, the full torque will be on the central, driving shaft, while some smaller fraction will be on the upper shaft. As we bring the distance between them down, then the torque between them can decrease, but then there will be more stress on the smaller pinions' teeth. Planetary gears are great for this class of problem and he's throwing decent diameter eccentric bearings in where he can too. The bloke seems honest, and has clearly thrown a fair amount of time and energy into the problem.
There are other approaches to controlling gear ratio via the speed differences between two shafts - he's not trying to do something impossible, he's just trying to do something difficult, successfully. Whether the cost of the bearings and gearing will be favourable when compared to the other approaches is the question. I think his system will work - and decent sealed bearings, high strength pinions, planetary systems - these already exist and are stable tech in current transmissions, even in relatively dirty industrial environments where the transmissions aren't as protected as in cars. In particular, the cost of electronic control for motors has fallen massively over the last years, so if nothing else, the general class of solutions using differential speeds of low-torque motors to control a high-torque transmission is more appealing now.
So, 'genius', no. Hard-working, self-taught engineer? Yes.
Yeah, but maintenance on a manual transmission is a fair bit cheaper. Moreover, an automatic requires far more regular maintenance that, if not properly performed, can lead to much faster breakdown.
The way I understood it (could be wrong), the Prius drive is only one half of what this guy came up with. The clever bit is the other half. The Prius transmission would not work well without significant torque input/output(electric breaking) on the electric side. The way this works, there is almost no load on the ratio selection element, the only input it needs is enough to create a difference in speed.
Mind the frickin' laser...
The idea doesn't seem entirely new (and I'm not convinced it works).
http://www.freepatentsonline.com/3934492.html
I'm not understanding how this thing works. Can someone please use a car analogy?
What year was your car made? 1965? I've only heard of two automatic transmissions needing replacement and one was on a Prius.
Like this does?
http://www.gizmag.com/go/4909/
Unless you're talking about a torque converter in a traditional automatic transmission. It sacrifices speed (output is slower than input) and accordingly power (since HP = torque * RPM / 5252) to increase torque. For example: 200 ft-lbs of torque in at 5000 rpm (about 190 hp), and you'll get back out 215 ft-lbs at somewhere under 4600 rpm... The slippage actually increases torque (albeit at the expense of total power)...
If a man isn't willing to take some risk for his opinions, either his opinions are no good or he's no good
I was refuting a raft of claims in response to the parent that claimed the Prius used a conventional CVT. It clearly doesn't.
As far as the claim that the secondary drive motors don't need significant torque. That remains to be seen IMO, nothing is clearly shown from a plastic model.
I don't mean to be a skeptic, but I guess I fall into the camp that doesn't understand this. It seems that the control shaft is just used to undo the motion of the main input shaft. For instance, to go in reverse, the control shaft has to be going faster than the input shaft and would then be doing all the work. Furthermore it doesn't even solve the CVT part of it because the control shaft needs to be able to move through the same large range of speeds that the output does. If you had a control shaft that could do all this, why not just hook it up to the output?
Can someone explain to a non-engineer where I've gone wrong?
Combustion engines need variable transmission because they have small optimal ranges of output torque and RPM. However, for hybrid drives, you can simple direct all output from the engines to charge up batteries and drive the wheels electrically. Wouldn't this bypass the need for an infinitely variable transmission?
The difference is that when an automatic does go, the parts are more expensive and the job is more complex because there is no convenient place to put a point of failure. In a manual, the designed point of failure is the clutch pads. it is relatively simple to pull it apart and replace the pads. At most, in a well designed car like a Subaru, it is a 2 or 3 hour job. I've seen automatics take 2 days. At $90/hour for shop time the repair of an automatic means you eat ramen for a month, while the servicing of a clutch means you can have some steak.
Math is like sex. People who get it are popular in class, people who don't are not.
By the time I've replaced my $200 clutch 5 times, you've replaced your $2000 transmission twice.
APK quotes people (including myself) without context and should not be trusted. Just thought you should know.
Yeah, there's nothing like inching across the Bay Bridge in stop-and-go to make you realize the "fun" of driving a stick....
You just stated the definition of a differential gear. It is not new in any way, and describes exactly how a planetary gear works and is normally used. For a real world example take a look at the Hybrid Synergy Drive used in Toyota Prius.
I don't think it is the same as that. In the HSD the electric motor is contributing a large part of the output power, whereas TFA seems to be saying that the control power is significantly less that the power being transmitted, and hopefully will be less than the energy wasted in a friction based CVT.
The real icing on the cake is (as mentioned near the end) the secondary drive doesn't require a whole lot of power so it can be run by a flywheel
This is something that bothers me as I look at this demo. The secondary drive doesn't require a whole lot of power, because there is literally nothing attached to the output to counteract the little motor's selected ratio.
To simulate the forces of what it'd be to have a car attached on the output, you can just use your hand and try to hold the output from moving, while the ratio is not in neutral. If there is a weaker motor and a stronger motor, what do you think will happen? The stronger motor may feel a pinch, and the small motor will be completely unable to stop the output from distorting the ratios, making the entire setup unusable.
Now, I hope I'm wrong, but there better be something hidden from view That Changes Everything.
Yep, about 6%, coincidentally about the same percentage that suffer from serious mental illness
http://www.autoblog.com/2004/09/13/manual-transmission-may-become-extinct/
http://www.nimh.nih.gov/health/publications/the-numbers-count-mental-disorders-in-america/index.shtml#1
ElectricSteve writes with this excerpt from Gizmag: "Ready for a bit of a mental mechanical challenge? Try your hand at understanding how the D-Drive works. Steve Durnin's ingenious new gearbox design is infinitely variable..."
Sounds like a shameless bit of self-promotion that the submitter should have admitted to when making his submission.
AAAAARGH.
Right, I am not saying that one shaft will not be able to handle the torque just like the other, I am saying that the shaft that is supposed to be stationary when full speed is supplied to the wheels that the stationary shaft depends on something to stop it. That something looks like a perpendicular gear on it attached to an electric motor. So is the electric motor holding the shaft from moving, because if it is, then it has to supply as much torque into the system as the main engine (or some fraction of it depending on the difference in sizes of the two blue gears that rotate one against the other.)
You can't handle the truth.
Back in high school I was on the US FIRST robotics team, and a student came up with a transmission design that appears to be effectively the same as what's described here. It consisted of two input motors, whose relative speed determined the output speed. The main motor was attached to the sun gear of a planetary gear system. Around the sun, there were three planetary gears that were attached to the output shaft. Around the planetary gears, there was a outer ring gear, which also had teeth on the outside that were attached to the secondary motor. Thus, by varying the relative speed of the input motors, you could get the system of planetary gears to be stationary, or to rotate at variable speeds in either direction. This was back in 2003.
Once you get past all the extra machinery, it's a 3-shaft planetary differential being driven by two electric motors on the input sides, and with one output shaft. The "control motor" is geared down, so that it appears that a smaller motor can be used as the control motor.
This appears to work because there's no significant load on the thing. The output end is a small hand crank. If the thing was connected to a load comparable to what the "power" motor could drive, it would become clear. Actually, it's rather lame that he has to drive the "control" motor. With better design, it would be running as a generator, and control would be exercised by loading the generator.
You can just use a brake on the "control" shaft to the differential and get much the same effect. The Model T Ford did that. And, of course, many hybrids have a 3-shaft differential system connecting the wheels, electric motor, and IC engine, often with some brakes and clutches thrown in to keep the IC engine happy.
There are successful infinitely variable hydraulic transmissions. They're widely used on tractors, earthmovers, small locomotives, and other machines that need serious torque to get some big load moving. The design has no frictional components, but has some inherent unbalance and gets noisy at high speed, so this is mostly a technology for the world of big, slow, heavy, but very powerful machines.
Good point. Well, your numbers are a little off.
My car as 110,000 miles on it. I've raced my car a good bit (legal track racing, of course).
The first clutch (stock) I destroyed was by adding a 150hp NOS system on.
The second clutch (performance) was destroyed by my ex-wife driving it uphill and she slipped the clutch the whole way (like 5 miles). She obviously wasn't very good with a stick.
The third clutch (performance) was actually from old age.
My friend has a comparable car. It's the same engine, transmission, body style and weight. She drives more normally than I do (no racing, just city/highway driving). She had her clutch changed at 100k miles. Labor to replace the clutch is about $350 to $500. Parts are about $150. This car happens to be a bastard to work on, which is why the labor is high. So, $500 to $650 for the job.
This is about the age that an automatic transmission would need to be rebuilt. For this car equipped with an automatic, removal, rebuild, and replace costs about $3,500.
So, with my car, I've improved the efficiency by helping the airflow out (one minor exhaust fix, and a some intake fixing). I enjoy cruising at highway speeds with low RPM's (6 speed). The same car with an automatic would be cruising at a much higher RPM (4 speed), and suffering from losses related to the automatic transmission.
I rarely need to check my transmission fluid (i.e., gear oil). If my gear oil runs low, it could increase wear. A car with an automatic has to have their transmission filter and fluid changed. If their fluid runs low, it can be catastrophic.
There's about a 300 pound difference between the manual 6 speed and the automatic 4 speed.
So, lighter, better fuel economy, and less repair costs. I really don't see why people wouldn't want to drive a stick. The excuse "I don't know how" isn't a valid excuse, except they're too lazy to learn.
I can drive pretty much anything with wheels, and I've proven it. I'm licensed for motorcycles and cars. I've also driven everything including a big truck with a 10 speed air shifter. a neighbor bought a motorcycle, but didn't really know how to drive it. They told me it wasn't driving right, so I grabbed my helmet from the garage (I don't have a bike right now, but I still have the helmet), and took it for a spin. It worked fine. It was operator failure.
Serious? Seriousness is well above my pay grade.
Could this device make a new kind of hybrid possible?
For this auto, at a given speed the internal combustion engine will be running at optimal efficiency rpm range while the electric engine is used to get the required energy input for the variable transmission system.
How efficient such a car could be compared with cars equipped with conventional gear boxes?
How big the batteries and electric engine have to be to make it work? And how much can be internal combustion engine be reduced without loosing too much performance?
I am quite skeptical that this could work. I know someone who spent a lot of his life trying to create such a system using the same ingredients (planetary gears), and heard from him that someone had proved in a paper that it was impossible. He was trying anyway. I suspect there is some hidden catch.
The
Yeah, like what happened with the magical carburetor. BTW, I've got a pal who is selling his '69 Mach 1 really cheap, in perfect shape, because someone drowned in it, and they can't get rid of the smell.
Read the comments on the linked article. If the submitter had bothered to do that it would have saved us all some time, the useless cunt.
I just sketched a venn diagram of that. You didn't show any relationship between the two circles.
Most of the people I've met who have mental illnesses either don't drive, or they drive automatics.
I hope this clarifies things.
Serious? Seriousness is well above my pay grade.
The skeptic in me can't help but dream up military applications of new inventions. In this case I can see a major WMD forming by using D-Drives as ultra-low-frequency transducers. (an examle of another motor-driven ULFT)
Massive D-Drives could be used to couple a large sea vessel's engine(s) to large baffles on either side of the vessel, and upon engagement could simultaneously push huge amounts of water in and out, creating an artificial tsunami. One boat couldn't do a lot, but a fleet sure could. The wave generators could be synchronized and the ships aligned in an arc to focus the tsunami on a specific shore position with no significant ill-effect to the rear, and the magnitudes would combine at the target plus be amplified by shallowing water. There would be absolutely no defense except a perfectly aligned and synchronized reciprocating wave generator array, which would be very difficult to defend against an air attack.
The scary part is that we're not talking about just one big honkin wave, think hundreds of them, sustained as long as the fuel supply allows. Meanwhile, on-board marine nuclear power plants have long been in service already, all set to unleash that power upon any coastal city or military base without the fuss of nuclear fall-out. It'd actually be as eco-friendly a WMD as you'll get.
Surf's up!
War as we knew it was obsolete
Nothing could beat complete denial
- Emily Haines
Am I the only one who wants to slap the camera man in the back of his head? It's hard enough to understand the demo without him changing angles like a kid peeking at a new toy.
This post contains no rudeness or derision of any kind. All arguments are friendly. Terms and exclusions may apply.
It has two - he just renamed one of them as the "control shaft".
NTSHF,MAN.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
ON his website http://infinitelyvariabletransmission.com.au/ he links to a report that he commissioned by an engineering firm. If you will read the report it actually goes into much more detail and explains most of this. Link to the report http://infinitelyvariabletransmission.com.au/wp-content/uploads/2010/05/dDrive-Transmission-Report.pdf It actually goes through many of the objections I have read here.
'series' hybrid, not 'serial'
I just got up and I'm on Slashdot. Hard to switch gears (as it were) between circuits and gears. My bad.
I'm not sure about not needing a lot of power; sure, definitely not in neutral, and not at "max gear", when it can be simply locked to not fight & keep the "control" shaft in proper position. But in between those two a large part of power will often have to come from "control", there's no way around it. OK, you keep the RPM of the "main" engine constant - but that's not its only property. From where comes counterbalancing for fluctuating torque?
Might still be mighty usefull for simple, cheap hybrids.
One that hath name thou can not otter
It's quite different from the HSD in that it has three inputs, contrary to what GP said - one power input, and two control inputs, both of which ought to require just a fraction of the input power to control the input/output gear ratio. Watch the video in TFA instead of instantly dismissing it as "has been done before".
But is has two inputs; the second is just called "control" in those demonstrations, and "very small electric engine" is enough since there's not much load.
One that hath name thou can not otter
We have a winner.
Torque is like a force wrapped round an axis, and the same laws apply. Including the one about an equal and opposite reaction.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
No, the most efficient point is at peak torque. That's where the engine is able to produce the most energy for a given amount of gas. The horsepower peak is where the engine is producing the most power (energy/time). It is not necessarily it's most efficient point unless they coincide which is rare.
In contrast doesn't a manual need a clutch replacement every 100,000 miles due to wear during shifting?
That depends on how well you drive. I've no doubt an incompetent driver could wear out a clutch in less than 100,000 miles, but there should be no wear at all when changing gear - only when moving off from stationary.
I've had quite a few manual cars and I've never had the clutch changed on any of them. My current car is pushing 160,000 miles on the clock, and my best score was over 200,000 (when I changed the car, not the clutch).
> Show me a dry clutch as used on most cars that outlasts an automatic
> transmission.
any that is being operated by someone who knows what the hell he is doing.
Tractors don't use torque converters. There's a reason for that.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
you need this
http://www.downloadhelper.net/
I have a slow connection also, so this thing "just works" for vids
For me, as a non-engineer, this is quite difficult to get my head around although the example of the differential given above is a useful one. The bit I don't understand is why the secondary motor to control the ratio doesn't require the same power as the primary motor. For example, given the differential set up described above, wouldn't the second motor (where one of the wheels would normally be) have to provide just as much power as the primary at any speed other than full speed (where the secondary motor could be locked)?
I guess the bit I'm missing is how speed but not torque is taken out the system. Anyone care to provide a handy link with some background reading? (Something other than "go get an engineering degree" ;-) )
Completelly different? How is that invention not, basically, an epicyclic differential? (but slightly more problematic, not symmetric in contruction) Apparently used in Prius. There are different torques involved, too...
One that hath name thou can not otter
Surprise! You can do Exactly the same thing with a Differential.
Nice little mech system. Allthough it's basically a system with a variable speed gear ring. (it's the english name for it I think?)
As has been stated above it needs another totally variable motor of about the same Torque/Power Range to really make it work.
Allso you'd need some sort of control mechanism since the losses in the system will vary. What happens while you're in neutral for instance? That input power has to go someplace, such as being dissapeted to heat or to drive an increased acceleration of the mechanical parts. Or for that matter, what happens when you're just moving the controll gear slightly? You've still got to counteract that torque on the gear ring, you know.
The torque from the main engine is applied at *both ends* of the lower shaft but in opposite directions. This means the 'bottom' shaft hardly requires any power to turn it. Your control motor only has to overcome the inertia of the shaft.
No sig today...
I hope you're not saying what I think you're saying. Transmissions CAN'T increase horsepower. All they do is keep the engine from stalling by trading speed for torque. Horsepower is rotational speed X torque so the total horsepower doesn't change just the ratio of torque to rotational speed.
I think the transmission design is very cool and I'm amazed that someone can still come up with new ways to combine gears that haven't been done before. In fact, there was a post claiming someone had come up with a substantially similar design so maybe it isn't really new after all. For safety reasons the D-Drive will probably still require some sort of clutch since a sudden failure of one of the inputs could do really bad things to the driver and the vehicle.
"Meaningless!, Meaningless!" says the Teacher. "Utterly meaningless!"
You've got the volumetric efficiency relative to rpm part backwards. Volumetric efficiency goes down with rpm. Thermal losses go up as surface area of cylinder goes up. However, pumping losses etc go up with rpm. So, the most efficient engine is one that is able to produce the most torque out of the smallest displacement. Or in other words, run at the lowest rpm to meet application's power needs. This is what lies at the heart of why you see in countries where fuel is more expensive than in the US the majority of cars sold are turbocharged diesel engines even though these engines are much more expensive to make than gasoline engines -- they get high power at low rpm the way large engines do but have lower surface area in cylinders). In other words, they are large engines stuffed into small displacement using positive pressure induction and high compression ratio. Another example would be how, if you have a manual transmission car, you'll notice that operating at higher rpms exponentially decreases mpg. A corvette with almost twice the power of a car like a Honda S2000 will actually get better gas mileage in any conditions where the drivers are using the full power of the vehicles (eg racing of course but even just driving them like sports cars are designed to be driven on mountain roads or whatever).
Hate to reply to my own post, but here is a fairly detailed explanation of John Deere's IVT: http://salesmanual.deere.com/sales/salesmanual/en_NA/tractors/2006/feature/transmissions/8030_option_code_1127_1137_ivt_trans.html . The relevant part is "The John Deere IVT uses a hydromechanical, power-splitting design where a portion of the power is transmitted mechanically and a portion hydrostatically. A hydromechanical transmission is more efficient than a purely hydrostatic transmission because gears carry power more efficiently than a hydraulic pump and motor. By careful selection of the gearing, the John Deere IVT carries a maximum of the power mechanically both at normal field working speeds and at transport speeds, taking maximum advantage of the higher mechanical efficiency while providing the control and versatility of a hydrostatic." And of course this power-splitting is done via a planetary gear system.
I say this not to take away from the D-Drive's awesomeness (John Deere doesn't do reverse without shifting a gear), but to help offer explanations of how it actually works.
Have a look at the agco/ fendt tractor transmission design.
That is also because it is much more fun : reving while downshifting, shifting at the exact moment you decide (a lot more than merely useful on frozen roads, or on snow), that is fun. Pushing on buttons is for handicaped people, and that is good for them, but no more, no less : I will never be able to understand healthy people that use automatics. The moment when driving stops being a pleasure, you turn sleepy, and you get to be far more dangerous than people doing crazy speeds on open road (and though I enjoy driving, I am not one of them : high speed is on the track, not on the road, for me).
Automatics are only vaguely good for city driving, to avoid jerky shifts for people that do not know how to drive... but if you know how to do this, no jerky shifting. Which as the enormous advantage to avoid an unnecessary complicated gearbox, that will end up being more fragile, reducing the lifespan of the car. Sure automatics allow for fuel savings... but the complexity impliying fragility, it means the car will last for a lot less time. And accounting for the need to buy another, plus the fact that not all of it will be recyclable, I am not sure it is either economically or ecologically relevant in any way.
I am really happy to live in Europe, still quite spared from the automatic-plague... though I am amused so-called pleasure-cars like Ferraris have abandonned any manual alternative... it just proves those are poser-cars for clueless professional-drivers-wannabees. Yes automatics shift faster, which is useful in competition. But neither road nor trackdays are about earning the last bit of time : those should instead be about pleasure, where manuals reign sovereign.
Both automatic transmissions and manual transmissions (well, mainstream ones. I'm not meaning the Justy's ECVT or others), both use friction surfaces that eventually wear out. Manual transmissions have clutch plates. Automatic transmissions use brake bands actuated by fluid pressures and planetary gear systems.
Brake bands wear out eventually, thus causing slipping, and eventually will need to be replaced (thus a rebuild.)
Frictionless? This is almost too good to be true, there has to be some catch
Well, first you do have to listen to a pitch for a timeshare, and then it turns out it's only a 1/2000 chance it will actually be frictionless...
The largest value of this device is in its "wow, how does that thing work?" design. By baffling the onlooker and also describing the widget very carefully the illusion of a wonderfully useful device can be created.
It has a problem in the real world, though. The reaction torque is equal to the working torque - and the reaction torque path runs through that "secondary control shaft." This will become obvious as soon as he tries to transmit some significant power through his device. What he's showing isn't a new invention at all, it's just a mechanical "summer" that adds the inputs from two input shafts. All that's new here is some fancy handwaving and creative description.
It might be good enough to fool some people but Mother Nature and those who paid attention in school aren't fooled. Maybe if / when he actually tries to transmit some power through his "invention" and the control motor just spins backwards he'll "discover" a source of electrical energy?
I did watch video in TFA, and it doesn't make it clear how this device works. It does suggest, however, that they haven't actually made any real measurements yet, so whether it works as they think remains to be seen. Regardless, what I instantly dismissed was the GGP's claim that combining two inputs to an output is anything new.
Didn’t a Japanese company (Honda?) already have those, a decade ago. If not much more?
I always assumed infinitely variable transmission existed since I was a child. Wait, so it must have been at least 20 years ago that I saw that photo and article of what was definitely a production vehicle being sold everywhere.
Any sufficiently advanced intelligence is indistinguishable from stupidity.
I wonder if its possible to make five figures of power from a 7 litre?
No. A top-fuel drag race engine produces a bit under 10000 shp. It runs at the verge of hydraulic lock (ie the gases in the cylinder start to behave like liquids) so there's limited scope to increase power. Oh, and these engines have a lifetime of 10 seconds.
Higher amounts of power are possible, but 500 shp/litre is way off for engines that need to run reliably for 10^6 km.
An infinitely variable transmission does allow you to use extremely peaky engines - not just those tuned for very high power, but tuning for maximum efficiency also leads to an engine that only runs well at one speed.
Well, this transmission looks quite complicated and with a lot of moving parts. It would be PERFECT "for auto dealerships and other auto repair companies" ;-)
Moreover, an automatic requires far more regular maintenance that, if not properly performed, can lead to much faster breakdown.
I've not had any maintenance done on my cars with automatic transmission since 2000, so the problem is a bit exaggerated here. I'd estimate that you'd need a comparable amount of maintenance on your arm when you use manual transmission ...
"I love my job, but I hate talking to people like you" (Freddie Mercury)
My instinct is that if the device is truly symmetrical you'd need two equal engines in your car to achieve the "continuously variable output speed" and in full-forward or full-reverse one would be turned off and presumably locked. The back side with the second electric motor is never shown in the video. I want to know why it doesn't have it to be equal in power to the primary engine?? Note that in the video there is no load so zero torque and therefore zero power is being transmitted through the device.
If the two motors are indeed equivalent in requirement, you can do the exact same thing with a common solid rear axle with an open differential: connect two engines to the two ends where a wheel normally attaches. The "output shaft" of your holy grail is the axle's driveshaft coupler and it spins at some designed multiple of the difference between the two engines.
hunker down in its sweet spot and let the tranny worry about all the fiddly bits
I've spent too long on the Internets, apparently.
~ C.
The Prius uses a single torque differential. This uses a pair of them reversed onto each other. The "output" on the Prius is the input on this. The two "inputs" relate to the two shafts. The unique thing about this is that it uses the two shafts and the relative motion between them to control the output speed. So while it uses some similar parts, the theory of operation is completely different. Just because it uses a planetary gear set, doesn't mean it's the same...
If a man isn't willing to take some risk for his opinions, either his opinions are no good or he's no good
But basically it seems to be the saem part but operated in way / with the "goal" of keeping the engine at constant RPM... (however much power would be required from "control" shaft to do that)
One that hath name thou can not otter
The 'doubts' the inventor has aren't with the mechanics or the gearbox mechanism, they're with fuel efficiency.
Spinning up the bottom shaft throws away the energy from the engine (it's like injecting mechanical 'grease' into the gearbox). ie. The car engine is running at full power when you're sat at a traffic light but all the energy is being thrown away.
You can obviously reduce the throttle to eliminate waste, reduce the engine RPM when idle, increase it when accelerating hard, etc., but figuring out if this will work out to be more efficient than a traditional engine isn't easy. A lot depends on the engine management systems and they're never been used this way.
Another problem is driver acceptance. I once owned a car with CVT and it's weird to drive because the engine sound doesn't doesn't give any cues as to what the car's doing.
No sig today...
No, all that matters is *speed* difference, not power difference. So you can use a low-power motor through step-up gears to make the 'control' shaft run the same speed (and faster) than the 'power' shaft. The big problem is that it will try to transmit some of that power back through the second shaft.
To me, as others have also noted, it looks like a more complicated version of the Prius' transmission, designed for a single-speed input. While yes, this may be useful for a gasoline or diesel engine system where the most efficient engine speed is at one specific output speed; you're still having to 'waste' power by diverting that power to the second shaft.
With clever integration, this would probably increase the gas mileage of a non-hybrid car, and at the same time allow for maximum torque at all speeds, it is not much more than a stopgap to primary electric systems. And with electric-drive systems, you don't need this complex a transmission, you can get away with a very simple gearless one.
Of course, I'm sure this has other applications that don't apply to automobiles that I'm completely missing, so it is still a fairly impressive system.
Sorry, this is only because of the drivers in it. First generation of prius saw the same behavior here in the Netherlands. Because the people buying it were the fuel efficient treehuggers. However more recent there are tax deductions for low emission cars and now the prius is popular also for lease. They show that the prius can be quite a fast car if you are not afraid to put the "gas" peddle down and make some engine noise. And because of the CVT and relative high torque of electro car it can accelerate quite efficient. It says you can go from 0 to 100 in 10 secs, but the nice thing is that also a not exprierenced driver can do this by just flooring it and let the E-CVT figure it out instead of stick-shifting it in the exact right second.
GP: determined by the *difference*
P:two inputs summing up to one output
See the difference? (haha, I made a pun)
efficiency is over-rated, and there is no substitute for displacement.
pretty happy with my three-on-the-tree and 502cid.
Are you saying an engine produces the same HP at idle as it does when you redline it? Don't fucking think so.
Yes, I think it probably is.
The way I see it you'll have a big problem with fuel efficiency. The reason the upper shaft slows down when you spin up the bottom shaft is that you're throwing the power away.
A more traditional CVT isn't as robust but it never throws power into the void.
No sig today...
Not true. Volumetric efficiency is measured as the the volume of air taken in on each stroke vs the displacement of the cylinder. So if 1 liter of STP (Standard Temperature and Pressure) gets drawn into the cylinder, and the dispacement of that cylinder is 1.2 liters, the total efficiency is 1/1.2 (or about 83%). At 0 RPM and 100% throttle (well, any throttle position that isn't completely closed), volumetric efficiency is always 100%. But as the engine starts turning (at full throttle, otherwise the vacuum drawn by the throttle restriction will reduce efficiency), the actual efficiency will depend on intake design. Considering that OTTO cycle engines use valves, air is only drawn in 25% (about) of the time. So the vacuum drawn trying to draw that air in will cause the efficiency to drop. However, intake runners are designed for this. So basically, when the valve closes, the momentum of the air causes a pressure build up behind the valve. That pressure will cause the air to reverse direction. This leads to a harmonic wave in the intake runner. The frequency of the wave is dependent on the design of the intake runner (cross-sectional area, cylinder volume and length mainly, but curves and other obstructions do play a part). If the valve opening is timed properly with this frequency, the incoming pressure wave from the harmonic will actually force air into the cylinder. That's how some racing engines can actually achieve a higher than unity volumetric efficiency at a specific RPM. It's all relative to the design of the engine. Some engines may be designed for 2000 rpm. And increasing the RPM over that WILL decrease VE. But you cannot say as a general rule that VE is inversely proportional to RPM, because it isn't. And pumping losses are directly proportional to VE (in fact, the pumping losses are DUE to VE below 100%).
You do have a point that thermal and mechanical losses do increase with RPM (Mechanical due to friction, thermal due to the increased movement of air around the parts). However, your reasoning behind diesels being more previlent is flawed. It's not because they operate at a lower RPM. It's because of a few reasons. First off, diesel is denser (energy/volume) than Gasoline while still having a similar stoichiometric ratio with air. Secondly, diesels are typically built without a throttle blade. That means that even at idle or lower power settings, there is no restrictive plate to draw a vacuum (and hence harm VE). Since diesel doesn't behave as bad as gasoline when run lean, they typically control power output by controlling the fuel flow. Third, diesel engines tend to burn much hotter than gas engines (the flame front is significantly hotter), so there is a more complete burn. You combine these effects, and you can see why they are more efficient (and it's not because they run slower). The reason that diesel engines typically run "slower" is two fold. First, since diesel engines don't use spark plugs, timing is controlled by the mechanical fuel injectors (direct injection). They were simply not fast and accurate enough to time at high rpm. The second reason, is that diesel is slower burning than gasoline. So at higher RPMs, there's a large chance that combustion won't be complete when the exhaust stroke starts (resulting is a large drop in efficiency and a large increase in mechanical stress).
If a man isn't willing to take some risk for his opinions, either his opinions are no good or he's no good
6 (forward) gears isn't that many - it's the minimum I'd expect in a new car these days.
Needing all 6 to stay at 2k revs from 10-60 is terrible too. Your fuel consumption at 90 is going to be horrible, where a better set of gear ratios could've kept you close to 2k revs at that speed.
My car is four years old, is cheap and nasty, and does 70 in 6th gear at 1500rpm. I get rather nice fuel economy at that speed, and even at 90 I'm doing well.
It's quite different from the HSD in that it has three inputs, contrary to what GP said - one power input, and two control inputs, both of which ought to require just a fraction of the input power to control the input/output gear ratio.
Real engineers disagree on the "inventor's" website:
http://infinitelyvariabletransmission.com.au/wp-content/uploads/2010/05/dDrive-Transmission-Report.pdf
"The torque provided by the Control shaft will typically be of the same magnitude as the torque provided by the Input shaft."
"The Control shaft (and associated mechanical elements) should be sized to this torque requirement
accordingly – the Input and Control should be considered as parallel power paths rather than as ‘power’
and a ‘control’ elements respectively."
So this whole thing isn't very useful. To add this as a transmission to a power motor, you need
one ore two additional motors of same power with variable speed and enough torque at any speed.
I'm sorry, I have no clue what all this means. Not just this post (which I randomly picked to reply to) but about 99% of the posts.
Could we please have a computer analogy to clarify things ?
while (true != false) process_more_stupid_code();
That's the same thought I had when I saw the pictures. The reason it works is because the sun gear provides the counterforce to get the planet gears in motion. If there's a load on the planet gears it'll push back against both ring gear and sun gear, meaning the drive force on those will have to be equal. No use having a weak motor driving the sun gear.
Just have a look at how an automatic gearbox works. (I already learned about those over 20 years ago when I was taught about cars instead of computers)
home
So buy a Prius. It has the same mechanism in it. The two drive sources are the gasoline engine and a motor-generator MG1. See an animation of it here: http://eahart.com/prius/psd/
The determined Real Programmer can write Fortran programs in any language.
It would seem to me that this is an ideal application for a (diesel) turbine engine. A turbine has very consistent RPM/torque output: this is why, despite its efficiency, they have not been used in vehicles with any regularity.
If you could "seamlessly clutch" from "stopped" to full speed, back to "stopped" and then into reverse all while remaining at a consistent, low RPM, you'd have the perfect transmission for a diesel turbine. Very exciting! We might be able to significantly increase the petroleum efficiency of our new production ICE vehicles without being dependent on expensive, radioactive, inefficient rare-earth metals! (That's only a very short-term solution, anyway: it'll only last a couple years longer until people realize the overall cost is significantly higher.)
Furthermore, it looks like this transmission might be easily shoehorned into existing (low-RPM) diesel vehicles and realize a performance increase, provided it's not an inefficient design - the video looks like it's got fewer points for energy loss than a traditional shifting transmission, at any rate.
~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
And from the same link you provided (emphasis mine):
later followed by:
Thanks. I rest my case. :-)
First of all, yes, I did read the whole article.
I could be totally wrong on this (but I don't think so...), but there doesn't seem to be anything new here. This is just a differential (like those between the right and left wheels of a car) where the input drive is the same as the input drive on a differential, the output drive is one of the wheels, and the electric motor that determines the gear ratio is in place of the other wheel.
They will find that the electric motor is really being run as a generator in lower gears, and so is actually just taking away energy, not increasing the torque.
I invented something like this when I was just a kid playing with Lego blocks. One of the pieces was a differential and I tried to create something like this, but then determined that it would only lose energy, not actually create a different gear ratio.
The vital thing that they are missing is that the way it is built, it is always trying to go into a lower gear. So even if you put a fly wheel in place of the electric motor, it would just spin faster and faster until the transmission was in neutral (as soon as you put any load on the output drive).
No holy grail here (unfortunately).
Yeah but eliminating clutches removes a common point of failure. So even if the performance benefits aren't that great it may increase the life of the car/machine.
Not in my reality, they don't. (Floating above the desk as I type)
I'm just glad that Pete Rose found a hobby.
I feel sorry for people that don't drink, because when they get up in the morning, that's as good as they're gonna feel
Not a mechanical engineer here, but if I understand TFA, the two inputs are not summed, one is only for control of the output of the other input.
Sure automatics allow for fuel savings..
;-)
Really? I've only known them to be slightly higher in fuel consumption because of the powerloss in the hydraulic converter.
Yes automatics shift faster, which is useful in competition.
That wasn't the case when (I believe) Top Gear mentioned a test between a new Porsche automatic gearbox and a manual. The manual did better on the track, although the cars had been driven by a professional ofcourse. Regular punters will skew the results.
home
Not at all. This device has three inputs, GP neglected to mention the main engine. It uses two smaller inputs to affect the main larger input. The prius balances two engines of rougly equal size. This controls a single engine with two much smaller ones. It seems to be a novel and unique transmission.
That's largely due to lack of maintenance, but also due to the cheaper transmission construction.
Most people don't realize that transmission fluid needs to be flushed regularly. It may be a closed system, but it's got metal-on-metal contact, lots of heat, and a fair amount of friction. The transmission oil breaks down at a molecular level due to these high levels of heat.
I've met people who did not realize that transmission fluid even needed to be changed. I know a guy who burnt out a transmission with only 12k miles on the engine/transmission: it was a 30-year-old vehicle and the transmission fluid had not been flushed since it was first constructed. Well, guess what: petroleum products break down with age as well as heat.
You're supposed to change your tranny fluid approximately every 20-40k miles, depending on the vehicle, how it's been driven, and so on. A good transmission (Mercedes) could probably go 100k without changing; a bad one would likely need it every 20k, and still not last all that long (1990s Ford Taurus).
You're supposed to change your fuel pump filter every year or 10k miles, too. I'm sure there are vehicles out there with over 100k that have never had it done and still running fine (due to the use of different fuel tank materials that don't rust, I'd suspect).
~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
I've seen someone smoking, talking on their cell, and holding a cup of coffee - all while driving. That's skill.
~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
With a manual, it depends a lot more on the skill of the driver at clutching.
I've got a friend who has a manual diesel with 980k miles on it. He doesn't use the clutch: he's able to 'feel' the vehicle well enough to not need it, and can shift seamlessly. It's quite the feat to watch.
~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
You should read the posts above that show why the transmission in a Prius isn't anything like this. Just having two inputs doesn't make it similar.
wet clutch? ohh you mean that "exotic" DSG style automatics. Not what is in most ford/chevys/GMs, a hydrolic automatic.
All of the above was encrypted with a Quad ROT-13 method. Unauthorized decryption is in violation of the DMCA.
...there should be no wear at all when changing gear...
o.O
In the real world, what you describe is physically impossible.
"Convictions are more dangerous enemies of truth than lies."
Whether you add two or three power flows makes little difference to the principle of operation. You do not escape the fact that the "control" engine(s) will be experiencing a proportional amount of torque as the main one.
It seems to be a novel and unique transmission.
Well, many things seem novel and unique when you lack the relevant expertise.
Actually, this looks like it has a lot less parts than the typical automatic transmission, plus it looks like it can be reconfigured to take up a lot less space.
When our name is on the back of your car, we're behind you all the way!
There are cities in North America that have such steep hills that driving stick is impossible. San Francisco and Quebec City come to mind, I'm sure there are others. Quebec City has snow added to the mix for 4 to 5 months of the year - they even eliminate stop signs (normally present at most intersections) for cars traveling uphill in the winter.
Careful there. The mixing of terms. Torque != Power. Torque * rpm = power.
What the 'inventor' essentially did was build a differential - sort of like the axle of a car. The differential evenly splits its _POWER_ between the two wheels. If one wheel has almost no traction, that wheel will still get the same power as the other wheel. The wheel with traction will slow down (reduce RPM). The wheel with no traction will speed up. Power still evenly split. By manipulating the speed of one wheel, you can affect the speed of the other - you can even make the other go forward or backwards.
Now for the physics. If I apply 500 ft lbs of torque to a shaft going into a box, and their is an output shaft that is turning at 1/2 the rpm, the output shaft will have a twisting force of 1000 ft lbs. That 1000 ft lbs has to have that 'equal and opposite' force or the transmission will move. Most transmissions are solidly bolted to the engine (or have a torque tube going to the engine) that counters this torque.
So what the inventor is saying, that by applying just a little bit of power.... at the same rpm as output, he can essentially create (assuming the above numbers) a counter force of 500 ftlbs. So either he is wrong on his estimations (and until he puts a load on it he won't find out) or he will rapidly find that to match the input power's rpm, he will need just as much power.... So he builds one constant rpm motor and augments it with an equally powerful non constant one.
There are some differentials that bias the power to the slower turning wheel. They either uses clutches, or worm gears. I don't think either would help the cause here.
Excuse me? There plenty criticisms you can make of electric motors and the exotic materials needed for supermagnets, but radioactive is not one of them.
you can ... hunker down in it's sweet spot and let the tranny worry about all the fiddly bits
Sounds like a typical Friday night for me!
It's great to see IVT (Infinitely Variable Transmission) tech getting some attention again. It's important to note the it was invented around 1988 by Paul Pires in California. I remember reading about it in Popular Science or Popular Mechanics around that time.
Paul Pires is an electronics guy and designed the IVT using a circuit methodology that auto designers don't use. He came at the problem from a completely different point of view than anyone else before. The company that he Patented this under is called Epilogics, also in California.
His IVT has been fully functional for years and has the same benefits as this D-Drive claims to have. I would be very curious to know what the functional differences are between these designs, if there are any... I wonder if Paul Pires Patent has expired? I read that it has been theorized his design didn't get much uptake because car companies only wanted to use the designs that they had their own patents for, and their CVT designs were good enough that they didn't want to pay licensing fees to use his superior IVT design. In fact, his design is a breakthrough! It has been used in high torque trucks and was going to be used in race cars until racing rules were changed to not allow automatic.
Here are some pages with some more info on it with images of his design:
http://fuel-efficient-vehicles.org/energy-news/?page_id=960
Popular Science 1992 Article:
http://books.google.com/books?id=mgEAAAAAMBAJ&pg=PA30&lpg=PA30&dq=Epilogics+ivt&source=bl&ots=H7oaFk_PTZ&sig=OTtkBd1ddU8kRz_bgPmpl6-HIQE&hl=en&ei=lBLvS-_GDJDqsQPLi7X8BQ&sa=X&oi=book_result&ct=result&resnum=8&ved=0CC0Q6AEwBw#v=onepage&q=Epilogics%20ivt&f=false
http://www.autostechpro.com/heavy-duty-cvt-works-without-a-belt
Good point. Well, your numbers are a little off.
My car as 110,000 miles on it. I've raced my car a good bit (legal track racing, of course).
The first clutch (stock) I destroyed was by adding a 150hp NOS system on. The second clutch (performance) was destroyed by my ex-wife driving it uphill and she slipped the clutch the whole way (like 5 miles). She obviously wasn't very good with a stick. The third clutch (performance) was actually from old age.
My friend has a comparable car. It's the same engine, transmission, body style and weight. She drives more normally than I do (no racing, just city/highway driving). She had her clutch changed at 100k miles. Labor to replace the clutch is about $350 to $500. Parts are about $150. This car happens to be a bastard to work on, which is why the labor is high. So, $500 to $650 for the job.
This is about the age that an automatic transmission would need to be rebuilt. For this car equipped with an automatic, removal, rebuild, and replace costs about $3,500.
So, with my car, I've improved the efficiency by helping the airflow out (one minor exhaust fix, and a some intake fixing). I enjoy cruising at highway speeds with low RPM's (6 speed). The same car with an automatic would be cruising at a much higher RPM (4 speed), and suffering from losses related to the automatic transmission.
I rarely need to check my transmission fluid (i.e., gear oil). If my gear oil runs low, it could increase wear. A car with an automatic has to have their transmission filter and fluid changed. If their fluid runs low, it can be catastrophic.
There's about a 300 pound difference between the manual 6 speed and the automatic 4 speed.
So, lighter, better fuel economy, and less repair costs. I really don't see why people wouldn't want to drive a stick. The excuse "I don't know how" isn't a valid excuse, except they're too lazy to learn.
I can drive pretty much anything with wheels, and I've proven it. I'm licensed for motorcycles and cars. I've also driven everything including a big truck with a 10 speed air shifter. a neighbor bought a motorcycle, but didn't really know how to drive it. They told me it wasn't driving right, so I grabbed my helmet from the garage (I don't have a bike right now, but I still have the helmet), and took it for a spin. It worked fine. It was operator failure.
While I agree with much of what you have said, I call shenanigans on your assertion that 100k is about when an auto would need a rebuild. Other than in horribly abused vehicles, an automatic should last longer than that without needing service. While I hate car-related anecdotal evidence, I've personally driven two Ford AOD derivatives well over 100k without so much as a hiccup. The first, with an actual AOD, never had a transmission fluid change. The second, with the ever so unreliable AX4S, hit 155k before it was passed on to another driver. It still has not required a rebuilt several years later.
I'm not sure where he got inefficient either. Brush-less motors approach 95% efficiency, much better than an ICE's ~20%
404: sig not found.
A top fuel engine pushes the limits of HP/liter, but only for a 4-stroke engine under the technology limits imposed by the NHRA. You could do a bit better with free reign allowed to innovation, and a lot better by abandoning the 4-stroke engine for a turbine (although "displacement" is not really comparible for a turbine, other theoretical efficiency limits are far higher). But, yeah, top fuel is not at all relevent for road engines - the superchargers tend to detonate regularly.
The turbine in the Abrams tank shows how nifty that approach can be, with the ability to run on just about any fuel, reasonably quiet and reliable, and pretty decent power-to-weight ratio (the weight was presumably lower when originally built as a helicoptor engine instead of a tank engine, but it's still a fine example). If I could build a car around an scaled-down version, say 800 pounds at 500 HP and 900 ft-lbs peak torque, coupled to a transmission like the one in TFA, I'd be a very happy commuter.
Socialism: a lie told by totalitarians and believed by fools.
Simply put, it is not only possible but dead simple to hold two objects in one hand -- say, a sandwich and the steering wheel. When the shifting hand is available, either the sandwich is moved to that hand, or the shifting hand steers. Think of it as slow-motion juggling.
It could easily be argued this isn't very sanitary, since your steering wheel is probably one of the nastiest things you handle for extended periods. It may be a bad idea on this, and other levels, but it's very possible.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
Actually, this looks like it has a lot less parts than the typical automatic transmission, plus it looks like it can be reconfigured to take up a lot less space.
Looking again, it seems that you may be right.
Roberto
300 pounds more???? A turbo 350 transmission barely weights 150 pounds.
I watched the video, and one question was not answered... Is this effectively a clutch, or is it effectively a transmission?
This is a very important distinction. A transmission is a torque multiplier. At ratios below 1:1, you get more torque out of the transmission than you put into it. This is very important for cars, since they often need 10 times more torque at the wheels than is produced by the engine in order to start moving, or to haul a heavy load up a steep hill.
A clutch (or torque converter) works differently... It permits the engine to slip against the wheels. This is important, since the engine must spin, even when the vehicle is stopped. It must slip in order to start the vehicle from a complete stand still.
When this transmission is operating with one of the shafts unlocked, is it multiplying the output force, or is it simply wasting energy?
Also for off-roaders like me, manual can be almost a requirement in sticky situations. Now if Jeep would get their ass in gear and bring a diesel wrangler to the states, it'd be all good.
"It's ok, I'm completely secure as long as my iron is off"
Rofl
"It's ok, I'm completely secure as long as my iron is off"
Check out top fuel dragsters. They make around 8K horsepower out of an 8 liter engine, but the top fuel and funny car rules limitations on many things. So, yeah, doesn't seem that far off to get 10K horsepower out of a 7L engine. In these cars, nearly a thousand horsepower is going into running the supercharger. But, they use around 15 gallons of fuel for a single quarter mile run. :-)
Excuse me? There plenty criticisms you can make of electric motors and the exotic materials needed for supermagnets, but radioactive is not one of them.
Nor "inefficient," especially when compared to ICE.
it may increase the life of the car/machine.
Sadly, this may kill the project.
It seems that manufacturers don't want to build things that last forever. Planned obsolescence is the current fashion.
As long as insanity does not cripple the body, a person who drove stick for years then "lost it" would probably have no trouble at all continuing to drive stick. Once it's learned, it's burned in the motor cortex. I would imagine someone hallucinating would have concentration problems, but actions performed by muscle memory sorta just happen. Have you ever reached down to shift from fourth to fifth (or fifth to sixth if you have it) and found out that you ALREADY HAD, about five seconds prior -- or try to downshift, only to find that you never upshifted in the first place (and that this was the correct action)?
How many elite athletes have been or are absolutely stark raving loony? Mental illness does not have to interfere with learning new skills or putting old ones to use.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
So even if the performance benefits aren't that great it may increase the life of the car/machine.
If that's the case then it it'll never make it to market. Nobody would sell them. Cars that fall apart (forcing you to buy a new car) are more profitable in the long run.
Weaselmancer
rediculous.
A lot of the replies bring up problems of going completely with this solution (how do you get it started if you need things spinning first, how do you tow a car with one of these). Admittedly not an optimal solution, but a very effective one could be to still have a clutch in the mix for some of these situations. Considering that the clutch would only be used fairly rarely, and could be engaged while the rest of the system is in neutral (meaning it's fairly low engagement load), it could be much smaller and have a much longer life than the typical clutch arrangement.
Clutches don't have to have a short life. The clutch in one of my cars that I've owned since 20 miles now has just under 200K miles on it. I've been expecting to have to replace it for a decade. But, the way I drive it seems to pamper the clutch.
Sean
It's not impossible. I drove up to San Francisco once when we spent a few days there. I drove all over the place with no problems. Looking around online, the steepest roads are one-way downhill.
The worst have been private roads and driveways. I was invited to someone's house, and they asked what I was driving. Then they asked if it was a stick. Apparently a lot of cars simply don't have the power to make it up, and manual drivers can't do it if they're used to flat land or relatively tame hills. Everyone on that road drove 4wd SUV's. Moving vans have to park at the end of the road and the workers have to carry everything up by hand. Fire/rescue can't get there, so if there's a fire, they have to carry hoses from their truck up. That was a bit late for a neighboring house once. Really, that just sounds like a bad place to live (it was in the middle of an area very prone to earthquakes, mudslides, and wildfires).
If you look at the extreme 4x4 driving, where they'll do rock climbing, lots of them have manual transmissions. All an inclined road does is incur extra load, with the ability to roll backwards. Some places people are taught to use the handbrake to keep the car from rolling until they start building enough power to move uphill. I only do this if I'm pulling my car onto ramps, and I stop too early. It's a perfectly valid technique.
Automatic transmissions weren't available for a long time, and then were a luxury option for years. I know I'm talking about times before most of the readers here were born, but it's still true. Just because *you* can't drive a stick in harsh environments doesn't mean that your parents, grandparents, or more generations back, didn't. A lot of it is up to training and skill, which seems to fall short more often these days as we're softened with the modern luxuries.
Serious? Seriousness is well above my pay grade.
His gears are plastic in the model, but yes... I'd love to see some action other than spinning gears around.
Every time I start to have faith in humanity, I ruin it by driving to work between 7 and 8 am.
...those teeny planetary gears on the ends of the shafts are a serious weak link in that design (although it looks like it will work to me, I am not sure at all on longevity or being able to scale it up). They'll need to be made out of boron alloy chrome hardened cyroed and shotpeened dipped in yak butter virgin asteroid sourced unobtanium to stand up. The second weak link is the bars themselves, they will have a torsion bar-like set of stresses on them all the time, throwing the alignment of those critical for function planetary gears out of whack. Just look at it and visualize the (dis)harmonics and waves of conflicting stresses hitting on those gears. Micro wiggle city. It's gonna chew itself up in short order.
You see failure like this on only one end supported sealed bearings (not exactly the same, but good enough for illustration purposes) all the time (I see a lot of stuff like this on small engine gadgets, they hit a critical point of fast failure with little notice of impending doom). They last for awhile, but the pivoting non aligned forces on them cause way premature bearing failure.
Now, put those planetary gears in the middle somehow..maybe. How to do that...I got other projects right now, so..no idea. Sliding tubular interrupted shafts and all internal gears perhaps....
It's interesting, but the point is moot now with the switch coming to pure electric drive for small private vehicles. An electric motor is much more robust than this thing, and can handle power and torque just fine, and be wicked efficient, without near the complexity. ...or go to hydraulic drive...
it's just a couple planetary gear systems, instead of using brakes to lock into a single gear like most automobiles, slippage of gear holders is allowed. you can do that either with brakes (and lose energy by friction) or do with motors and pay the price in energy that way. Absolutely nothing here it that wasn't known a century ago.
I'm sick and tired of the extreme level of ignorance of science and engineering in our country, and how stupid ideas get acclaim because of it.
It also removes a redundant control method.
Throttle stuck ? - stamp on the clutch (and the brake) no problem.
This device has a "powered neutral" determined by getting two input shafts spinning at precisely the same speed - otherwise you are moving. You aren't going to manage that manually so you are likely looking at some form of electronic (+ software) implemented "neutral" switch. You'd better be worrying about how long before _that_ goes wrong - because it's going to be fun controlling the car when it does (without a clutch, remember).
Wow, good for you. Pretty much anything with wheels ... Air shifter 10 speed. We are all suitably impressed.
Fact of the matter is this. You comparison between 6 speed manual and an automatic is almost entirely invalid. Due to the wonderfulness that is a Torque Converter, Automatic cars/SUVs/Picukup/Real Trucks need fewer gears between first and final. On many autos the OD id a .5 or so lower than most currently available 6spds. I will give you the extra weight of many automatics.
I won't even start with the "Low on oil" issues you bring up as you statement completly ignores the mechanical issues with being low on oil/or having old/high mileage oil in a good mechnical transmission (gear spalling, bearing seizure etc. etc.)
Depends on how you look at efficiency, I guess. Efficiency doesn't have to relate to MPG - getting to your destination in half the time could be considered more efficient than saving fuel.
Fuel efficiency... well, that tends to on the shoulders of the torque curve, but - as you point out - peaking where the engine produces maximum torque. And even then, a car can be more fuel efficient by moving slightly outside of this area in order to operate at a speed creating less aerodynamic drag. It's worth having a look at "brake specific fuel consumption"...
http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption
Nope, still not there. TFA actually describes a device with *three* inputs: one "power" and two "control". The "power" is just that, power, always pushing at the optimum range of the engine. Then the difference between the two controls dictates if the output goes forward, stays still or moves backward (reverse). The device is described succintly as having *two* inputs since in logical (control) terms it has two inputs that you can adjust ... Kinda like you would describe a bath tub as a system with two inputs, hot and cold water, since the third one (water pressure) is taken for granted.
In the D-Device there's still a planetary gear, sure, but you're not using it to add two (power) inputs to produce a smooth output curve, as in the DRIVE of the Prius; you're using it (along with some other stuff) as a GEARBOX, i.e., to alter torque vs. speed delivery of *one* engine/motor. It's just that a)this gearbox is "infinitely" variable, i.e., the relationship between the engine output and the gearbox output can be "anything" you want; and b)it actually uses a couple of additional mechanical "inputs" to operate its internal magic, with no clutches, belts or chains, only gears all the way.
I'm not qualified to judge how innovative this is, but it is clear to me that it is not "just" a differential or "just" a planetary gear (i.e., I don't understand how it works, merely how it does NOT work ... not that TFA helps much to understand the former --or the latter, for that matter). Still, assuming the device is legit, I humbly tip my hat to Mr. Durnin and wish him a future of untold riches!
What the hell do you drive that the automatic is 300 pounds heavier. You're 100% wrong on that one.
No he's saying the ratio of the transmission doesn't affect the horsepower. If you trade speed for torque (or vice versa) then you end up with the same horsepower regardless of what the transmission is doing. (ignore friction in the transmission anyway)
It's great to see IVT (Infinitely Variable Transmission) tech getting some attention again. It's important to note the it was invented around 1988 by Paul Pires in California. I remember reading about it in Popular Science or Popular Mechanics around that time.
Paul Pires is an electronics guy and designed the IVT using a circuit methodology that auto designers don't use. He came at the problem from a completely different point of view than anyone else before. The company that he Patented this under is called Epilogics, also in California.
His IVT has been fully functional for years and has the same benefits as this D-Drive claims to have. I would be very curious to know what the functional differences are between these designs, if there are any... I wonder if Paul Pires Patent has expired? I read that it has been theorized his design didn't get much uptake because car companies only wanted to use the designs that they had their own patents for, and their CVT designs were good enough that they didn't want to pay licensing fees to use his superior IVT design. In fact, his design is a breakthrough! It has been used in high torque trucks and was going to be used in race cars until racing rules were changed to not allow automatic.
Here are some pages with some more info on it with images of his design:
http://fuel-efficient-vehicles.org/energy-news/?page_id=960
Popular Science 1992 Article:
http://books.google.com/books?id=mgEAAAAAMBAJ&pg=PA30&lpg=PA30&dq=Epilogics+ivt&source=bl&ots=H7oaFk_PTZ&sig=OTtkBd1ddU8kRz_bgPmpl6-HIQE&hl=en&ei=lBLvS-_GDJDqsQPLi7X8BQ&sa=X&oi=book_result&ct=result&resnum=8&ved=0CC0Q6AEwBw#v=onepage&q=Epilogics%20ivt&f=false
http://www.autostechpro.com/heavy-duty-cvt-works-without-a-belt
It looks quite clever on first glance, but I think he is fooling himself. The bottom shaft is going to get pushed in the opposite direction with as much force and speed as the top shaft pushes out. That means it will take just as much energy to drive the bottom shaft as it does the top shaft. If the bottom shaft is even slightly weaker than the top shaft, it will slip into reverse which means the car won't go forward at all. If you lock the bottom shaft in place, it won't require active energy but you don't get any "gear changing" benefit. Now if you drive both shafts at the same power level, you could use the same mother to drive both shafts with some clever gearing, but you'd be once again stuck with a constant gear ratio but you've got an awfully complex contraption. To change the RPM of the bottom shaft with relationship to the top shaft, you'd need a traditional gear system which defeats the whole purpose.
. Where this guy is fooling himself is in his thinking that the energy required to drive the bottom shaft is only a small percentage of the energy used in driving the main shaft. But that would violate Newton's third law of physics.
So what happens when the electric/hydraulic motor fails?
Did you see that the lower rod is also driven by the main engine? It's like one engine driving both parts of the Prius mechanism. Small additional torque on the control rod causes it to speed up/slow down, and it's the speed difference that shows up at the output. The vast bulk of the torques are provided by the main engine through BOTH RODS.
Since we are talking about transmissions, not cars I want to point out that my bike has 27 ratios and I need all of them. But maintaining a chain drive is a whole second career. Its not really for people who are not mechanically minded. It pretty much needs stripping down every 500 to 1000km. A transmission which can improve on that would be a significant improvement.
http://michaelsmith.id.au
Thanks for giving us the formal analysis. It also states the point that has been mentioned: "The Control shaft (and associated mechanical elements) should be sized to this torque requirement accordingly - the Input and Control should be considered as parallel power paths rather than as 'power' and a 'control' elements respectively."
There's a reason that that document includes a CVT in the design to power the "control", because the power that goes through the control is the same as the power through the input, so unless you have a convenient high-torque high-power variable-speed electric motor you might as well use the main power source. Of course, if you use an electric motor then it''s quite similar to a Prius, and if you use a CVT then it's pretty similar to the Torotrak, or some other IVTs.
However, this device does have a new feature. There are two different control inputs with different properties, so by switching which one you're braking and which one you're controlling with the CVT you can either go in reverse or at top speed, but still with a CVT's output speed always being positive and less then the input speed. However, that makes it complex for no gain (you could just directly gear up the output of the CVT to do that), so it seems like the things that are new aren't good, and things that are good aren't new.
Ewige Blumenkraft.
Buh? What makes you say that? Have you never heard of an e-brake?
I guess you meant force instead of energy?
This "Variable Speed" transmission is A JOKE!!! It is an overly complex but mechanically identical version of the Prius hybrid synergy drive planet and sun gear arrangement where an electric motor (AKA the generator) and the gas engine combine to produce a clutchless, constant mesh transmission that is infinitely variable and reversible. A real CVT would require ONE gas engine, no second electric motor/generator and use a simple effortless position lever that determines the direction and gear ratio of the transmission. That is NOT what Steve has built. He's made a Rube Goldberg contraption to fool the mechanically unsophisticated into thinking there is an invention here... Real CVT's exist in tractors, Honda has one in a motor cycle (see the wikipedia article on CVT's) and some diesel trucks have CVT's on their alternators. All of these use variable angle swash plates and hydraulic pistons or for low torque applications like the truck alternator, a ratcheting gear assembly. It annoys me when people get taken in. If you want a real mechanical puzzel to ponder, look up the Torsen Differential. That is a masterpiece of brilliant invention and engineering and is used on very large trucks). Simbuddha
Not really new. Model T's had differentials. And why are differentials called that? Because they "difference", as in subtraction, rather like Babbage's difference engine. All this thing is doing is distributing the speeds of 3 shafts so any 2 add up to the speed of the other. The wonder is that apparently no one has applied this idea in a transmission. Maybe that's because there's some fundamental problem, like, oh, how to drive 2 shafts so that the 3rd one can be precisely controlled? I suspect the electric motor used to drive the 2nd shaft may need to be so powerful that this idea may prove impractical. The inventor tries to get around that problem by having that electric motor act more as a brake, always running at negative rpm, so to speak. Notice that "top gear" is the 2nd shaft being locked to a speed of 0 rpm. The 2nd shaft could be run forward for an even taller top, but that would take real power, so this invention doesn't do that. We can hope that it works.
Perhaps most people on Slashdot have never played around with a differential? Jack up the rear wheels of a manual transmission, rear wheel drive car, and see what happens when you spin one wheel by hand. If the transmission is in gear (engine off, of course), the other rear wheel will spin the opposite direction, at the same speed. If the transmission is in neutral, the opposite wheel and the drive shaft will spin at some rate that together adds up to the speed you're spinning. Usually, the drive shaft will spin and the opposite wheel won't, because the wheel has the greater mass and inertia.
Also perhaps most people here have never had the experience of getting one rear wheel of such a car on extremely slippery ice? I'm talking ice right at 0 C, with water on top. (Well, if that's what road conditions are like, just stay home that day.) You might think you're okay if at least one wheel can get traction. Nope! If your vehicle doesn't have differential lock, you're stuck. The one wheel on a dry surface won't move, while the one on ice spins twice as fast.
Intellectual Property is a monopolistic, selfish, and defective concept. It is "tyranny over the mind of man"
Proved under what assumptions? Did they rule out every combination of gears, power inputs and outputs? I find neither "one guy tried it before" nor "somebody told me such was proved in a paper" persuasive arguments in light of a pretty persuasive explanation of how this works. My only regret is that I don't have my legos anymore -- I'd have a working model of this up within a few minutes, otherwise.
Waitaminute... the only thing stopping me from driving stick, talking on my cell phone, putting on my makeup and stuffing a big mac into my face is that I don't wear makeup and don't eat big macs. But I do drink coffee, talk on my cell phone, and stuff donuts into my face. And I guess... I used to smoke pot while doing all of these things -- in a lumbering '69 Ford 250 without power steering or power brakes. I loved that truck.
Ok. I am having difficulty to imagine is what happens when Vinput > V1 or V2? It appears the system is limited to the top speed of the ratio control motors.
The other question is what happens in the system when V1 == V2 == 0? Is all of the input velocity terminated in the eccentric gea-rset at the front of the system? Looks like a loss of Ratio Control power could result in over-speed of that gear-set and damage to the transmission.
Another possible question - what happens if V1 is powered in the wrong direction? It looks as if it would damage the ratio control system... i.e. tourque input could be transmitted to the ratio control motors.
Yet another possible question - what happens if V1 or V2 is allowed to freewheel? i.e. no torque applied?
Overall it appears that the power input required from the Ratio Control motors would be non-trivial...
Very interesting idea - though I have to doubt it is fully unique. At face value it appears to be an implementation of an amplifier in mechanics... variations of multi-input shaft multipliers and dividers have been around since early mechanical computers.
I drive stick in stop&go traffic all the time, and I've never understood this argument. Pedals make the car stop and go, auto or manual. Do you have trouble starting and stopping on hills or something?
The reasons to like stick are manifold, but one that's been growing on me recently is that in an automatic, my speed tends to creep up beyond the legal limit if I'm not ever-vigilant. That never happens when I drive stick, since I keep the motor running at a steady RPM without conscious effort.
D-Drive *is not* an infinitely variable transmission, it is continuous. The motor control is not of infinite resolution.
What? No mention of niggers, or anything? I am disappoint.
So then what happens if one were to hold the output shaft in place? Looks to me as if it would just transfer power to the "control" shaft through the final planetary gear assembly.
I walk. I don't have a clutch to change, just a $10 pair of shoes every few years, no labor cost. I weight about 2000-4000 pounds less than your car. Gas? I don't need any gas! So, lighter, better fuel economy, and less repair costs. I really don't see why people wouldn't want to walk. The excuse "It's hard and slow" isn't a valid excuse, except they're too lazy to move their fat ass.
Same AC here.
I'm not disputing the fact that manual transmissions have a lot of advantages. As you point out in your last paragraph, there are a people who are capable of maneuvering hills with manual transmissions, without any problems. What I wanted to point out was that days, the majority of the population doesn't wish to learn this skill, so they opt for an automatic transmission (which is still subject to slip on hills).
So while a certain subset of the population can drive on hills as if they're completely flat, most people will (sadly) opt for a solution that doesn't require learning.
As an aside, your uphill driveway story reminds me of a local boulevard that has a steep climb. The speed limit is 50 km/hr, and the cops love sitting on top of the hill because it seems that most people can't drive up a steep hill at a steady speed. Inevitably, drivers break the speed limit and the cops get to fill their monthly quota.
it actually uses a couple of additional mechanical "inputs" to operate its internal magic
"Magic" is the key word here. You may call one or two of the power inputs "control inputs", but regardless of what you call them they are power inputs into what is essentially an epicyclic gear set. No magic or any other form of hand waving will change the basic mechanics. The fact that the inventor thinks he has discovered something radically different doesn't mean he has.
I'm not qualified to judge how innovative this is, but it is clear to me that it is not "just" a differential or "just" a planetary gear
It is not "just" a differential in so much that it seems to be a combination of two differentials. I don't know if this is a particularly efficient way to construct a differential, lending it some merit, but there is nothing fundamentally new about its basic principle.
For details, please have a look in this very thorough analysis of the transmission.
Erm, it removes a redundant control system...in manuals, which are a small percentage of cars, and, rather obviously, would not be using this anyway. (Or, duh, they wouldn't be manuals.)
If corporations are people, aren't stockholders guilty of slavery?
Manual transmissions are lovely for a variety of reasons, especially in states where you have to deal with snow conditions. Mind you, a lot of modern automatic transmissions are pretty bulletproof. The GM 4T45E and Saturn MP7 come to mind and the Ford/GM dual clutch 6 speed should be a pretty solid unit. But there's that devil word. "Should." Automatic transmissions still aren't always as reliable as they perhaps should be. The automation leaves a lot of things to chance (Shift Flare in Aisin 5 Speeds), and sometimes people just plain push a design too long (Chrysler used more or less the same transmission from the K cars to the mid neons. By the late 90s all the power those neons comparatively put out, those transmissions got torn apart.) But the CVTs were supposed to be a holy grail. Like the VTi that has been known to blow up in 8000 miles. There are some promising designs out there (the Nuvinci comes to mind, the amount of torque it can handle for it's weight is quite astonishing,) but most aren't quite reliable enough at the torque a car puts out.. Manual transmissions, on the other hand, just plain work. The nature of them allows the parts to be much more overbuilt and good designs tend to be improved upon rather than have to be fully scrapped in the name of progress. Good Example: Saturn MP3 Manual Transmissions have been known to take over double the intended horsepower, with a stronger clutch and a welded differential pin. I'd like to see any modern manual hold up to that claim.
first dose is free, but make damn sure that they need to come back for more.
comment first, facts later. http://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm
One problem with this design - what happens when you you have a failure to drive one of the shafts (broken linkage, dead motor)? Full unintended acceleration is what. And it could be forward *or* reverse. Luckily such a sudden change would probably stall a gasoline engine. I think this design needs a lot of thought in the fail-safe department.
not a detailed exampl of deere tranny works, and a stunning example of a webpagethatsucks (to much text, not broken up right to make reading easy)
hunker down in its sweet spot and let the tranny worry about all the fiddly bits
I've spent too long on the Internets, apparently.
ROFLMAO
She had her clutch changed at 100k miles. ... Labor to replace the clutch is about $350 to $500. Parts are about $150. This car happens to be a bastard to work on, which is why the labor is high. So, $500 to $650 for the job.
This is about the age that an automatic transmission would need to be rebuilt. For this car equipped with an automatic, removal, rebuild, and replace costs about $3,500.
100K is when 4 speed transmissions from 20+ years ago AND from unreliable companies needed to be rebuilt. 1990 civic, not so much. Besides, 5 speed automatics are the rule these days, and are closer to the weight of manuals. 6-speed automatics are increasingly common as well (a few years ago I was looking at a Nissan and my choices were a 6-speed auto or a 5 speed manual, which really annoyed me). I'd bet that for average 1st owners looking to sell their cars today, those with manuals have already replaced the clutch (and dealers charge a lot more than $650 for that). The average automatic owner hasn't done any transmission work at all beyond maintenance.
Really, the only reason to drive a manual these days is because it's more fun. 'Cause it is.
All this guy is showing is one motor (the input) being slowed down by an opposite force from another motor (the control). Take away the fancy gearset and you just have two motors linked up in opposite rotation. Add a third motor of equal strength and you can go reverse at full power.
The gears just affect the torque necessary to accomplish this. The output torque will be reduced proportionally. Since he's not measuring the output torque, he's not demonstrating anything at all.
Notice the large first set of gears which upshifts the input torque to greater speed for the control shaft. By reducing torque, this creates the illusion (or simply allows) the control motors to be weaker than the input motor. But since you've already upshifted, the output torque will be reduced.
The first set of input gears is the only real gear here and it's predetermined. This is like a car constantly in 6th gear with an electric motor attached to the wheels to slow it down.
What this guy is showing is not transmission but BRAKING. No wonder he spends so much time bragging about the lack of friction!
The few tractors I have driven had a stacked wet clutch.. you need the stacked plates to get enough friction area to handle the high torque of the bull-low ranges, and the lubrication helps prolong the life of it/distributes heat.
"...the weaker motor would be completely unable..." Exactly. In this transmission, the output speed is a linear combination of three input speeds. There's no difference between the "main" and "secondary" drives that would let him use small motors for the latter. I believe the Prius transmission works the same - its output is a linear combination of three inputs (one ICE and two electric motors). Both the electric motors are substantial.
CVT transmissions operate by conical cylinders moving towards or away from each other and a belt running over those two cones makes the gear ratio (i.e. take two ice cream cones, and point the pointy ends at each other, when the two tips of the cones are just touching, that is the smallest gear ratio you can achieve (well really it is a little less because in a CVT, the cones would really be too far away from each other), then as you overlap the two cones so that the point of one cone is now aligned next to the base of the other cone, you can see that dead center between the two cones, it is now wider, and as you move those cones in and out, that the center diameter gets larger or smaller respectively). The belt that is in the middle between the cones is what is connected to the drive shaft of the wheels. That belt relies on the friction of being around the cones (which are rotating by the engine), to pull on the belt, which then turns the shaft which provides power to the wheels. The friction which is between the belt and the cones is the limiting factor for how much torque can be sent to the drive shaft. Once the wheels/drive shaft require more torque to turn than the friction bond between the belt and the cones can handle, the belt simply slips around the cones and does not move. This is why tractor trailers can not use CVT's as their standing momentum can not be overcome as the torque needed is higher than the friction bond between the belt and the cones, and thus the transmission simply slips, the belt heats up from the friction, and fails. This is why the other poster who talked about CVTs being used in commercial vehicles has no clue what he is talking about. The only place they are really used are in consumer class vehicles or ones with very low torque requirements.
We were all warned a long time ago that MS products sucked, remember the Magic 8 Ball said, "Outlook not so good"
I think that some torque would, by definition, be removed, as there is a relationship between speed and torque. Just like HP and Torque are different, more of one usually also means you have more of the other.
My understanding has always been that it's easier to subtract speed than add it, which is why the variable subtractor input doesn't require a lot of power compared to the power passing through the system.
But that does not answer your question. Makes me want to break out my Legos and model it. I wonder how one could measure torque on a spinning shaft cheaply.
Charging the batteries in a hybrid is no where near 95% efficient.
Maybe he was talking about brushed motors, they are very inefficient.
Pulsed Media Seedboxes
No, Toyota brought it to market first. The so called "power split" electric CVT was first described in a 1971 paper by some guys from TRW. It's an American invention. And yes, this guy is just doing a much more complex version of it. There is only discussion of speeds - all he's really got is a way overcomplicated differential. Once he looks at how power flows through it, he'll be very disappointed. It's a big nothing.
It's a differential, combined with some automatic gearbox planetary gears. :p
I'm not saying it's not brilliant.
I am actually amazed that it hasn't been done before.
Just one look at it and it makes so much sense I almost think I should have made it accidentally with lego as a kid
The reason the upper shaft slows down when you spin up the bottom shaft is that you're throwing the power away.
Hmm. Your last sentence makes me think you forgot about one of the laws of thermodynamics: There is no /dev/null for energy.
So what do you mean with 'throwing power away'? Where would it go in your opinion?
Zero is also a number 0 = 0 , both shafts are roating at the same speed.
You have 5 Moderator Points!
Which Helpless Linux zealot/MS basher do you want to mod down today?
I can't say that counterweighting would be all that difficult. This would likely be done with very specialized equipment (likely at manufacture) and obviously with computer support.
Adjustable weights could be moved in/out on the radial, and when the appropriate spot is found (by locking, rotating, and measuring the resulting wobble) "fix" the weight. The "fix" could be done such that it either includes the fastening system (pins for instance) or the fixing media (glue).
Doing this with computer support would be trivial. Doing it by hand would take lots of trial and error, and require you to run it at a far higher speed (as our eyes/ears/hands are not as sensitive as properly calibrated computer equipment - and would need a higher rotational speed for an off-balance to become obvious)
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
That's why the bodies rust and the bumpers cost so much to replace. Car manufacturers make a lot of money on spare parts.
My ism, it's full of beliefs.
Manual transmissions have the advantage of being less likely to completely fail without warning. I have changed two clutches and one main bearing and none of those events left me stranded.
They also leave you the option of push starting which I have had to do a few times.
The second clutch (performance) was destroyed by my ex-wife driving it uphill and she slipped the clutch the whole way (like 5 miles).
Now I know why she's your ex. ;)
February 9th, 2009 8:55pm: Slashdot becomes self-aware.
I do not know why an automatic would have more torque than a manual but I guess the torque converter would allow the engine to operate further up on its torque curve for a given slow speed. With a manual you would have to feather the clutch to get the same effect which is rather hard on it. The Pinto I owned was limited to slopes where the gas did not flow out of the fuel bowl directly into the venturi.
Exactly my first thought too. When load is applied to the output end, the torque is going to make that secondary spin unless additional force (aka bye bye increased efficiency) is used to keep it spinning at the target rate. The only hope is that the secondary motor has some mechanical advantage over the load, so it doesn't have to use as much counter-torque to keep the planetary at the desired rotational speed. They mentioned running efficiency tests at the end of the video, maybe this issue will come up in those tests.
Most rare earth deposits concentrated enough for mining (which is not a lot despite conventional wisdom that rare earth's are fairly abundant) are 'contaminated' with radioactive minerals. Uranium is potentially a by-product of newer techniques in rare earth refining.
lemonade was a popular drink and it still is
I'm guessing he's assuming you'd be powering an electric car with mains electricity (using a battery or an extremely long extension cord) in which case the non-oil based power sources are likely to be coal (which supposedly contains some radioactive material) and Nuclear (whose radioactivity is more obvious.)
Or he might be referring to Solar power, which I'm told, by a friend of mine who's the CEO of BP, actually involves a giant Nuclear Fusion reaction and enormous amounts of radioactivity across the electromagnetic spectrum being let loose across the entire Earth with no shielding whatsoever. Dangerous stuff this Solar nonsense, oil is much safer ;-)
You are not alone. This is not normal. None of this is normal.
Well, I didn't say it would be insurmountable, or even difficult to deal with. It's just a potential flaw. However, as others have pointed out, this device basically boils down to a single planetary gear system. There's no need even for the eccentric gear.
When our name is on the back of your car, we're behind you all the way!
Efficiency doesn't have to relate to MPG - getting to your destination in half the time could be considered more efficient than saving fuel.
Yeah but doesn't hold up in court. Although maybe it was just an anti-green judge.
You're thinking small. Why miniaturize the laser, when we could instead enlarge the sharks? -John Searle
...or you could just use a symmetrical, and accidentally much more clear to visualise mentally, existing variant of this "invention" from TFA.
One that hath name thou can not otter
So, lighter, better fuel economy, and less repair costs. I really don't see why people wouldn't want to drive a stick. The excuse "I don't know how" isn't a valid excuse, except they're too lazy to learn.
Damn straight. I drove auto for over 12 years, then a $1000 government subsidy on the manual version of the car I wanted prompted me to learn stick (the auto fell just short of the program's required fuel efficiency rating).
When I drove my new car off the lot, I had driven stick just 3 times--once test-driving a different make and model, the second was a friend's who coached me for an hour, and the third was test-driving the model I eventually bought.
Plus, not only did I get $1000 back, with taxes included I also saved another $1500 by not getting the automatic transmission option.
The real icing on the cake is (as mentioned near the end) the secondary drive doesn't require a whole lot of power so it can be run by a flywheel. Infinite torque? Frictionless? This is almost too good to be true, there has to be some catch. Like the primary input drive requires more energy than they expected but I can't see it--although I'm not a mechanical engineer.
That's the only bit of the story that I find hard to believe. Sure, if they have a Prius-type system where you basically have an internal combustion engine on one side of a differential and an electric motor on the other side, and the contribute equally, that makes sense. I just don't see how the secondary drive can get away with being less than a large fraction of the overall power.
Rampant carbon sequestration destroyed the Dinosaurs' tropical paradise. I'm here to help repair the damage.
I drive a manual, but I see two key disadvantages, both non-technical:
1) driving with an injured/broken left foot or leg, while not impossible, seems to be an extremely daunting task
2) in North America, people are less likely to know stick, so you might not have friends to help drive in case you can't or don't want to (e.g. case #1, drank a bit too much, tired, etc)
Say you put a vehicle with a standard differential axle on a lift... then you put an electric motor driving the tire clockwise on one side, now do the same to the other side.... voila when both tires are turning clockwise (looking at them face on)at the same speed the drive-shaft will not be turning however slow or stop one of the tires and the drive-shaft turns. It would seem to have the same function as a differential transmission albeit in reverse use ???
Another thought I had was the amounts of horsepower the D-drive needs, don't the HP requirements to each input shaft need to be balanced in a controlled ratio in order to control output speed/gear ?
FragHARD or don't frag at all
It also removes a redundant control method.
Throttle stuck ? - stamp on the clutch (and the brake) no problem.
Given the wide range of fly-by-wire systems and the rapid disappearance of the manual transmission, I think this is something that the industry is going to have to address properly, and soon. With older vehicles, as you say, there are several physical disconnects that the driver can use to stop a runaway vehicle. Newer cars with everything-by-wire don't have such safety features. When the first custom electric vehicle conversions started coming out, there was a lot of concern about runaway vehicles and such, and as a result, electric car conversions tend to have a prominent emergency stop button that forcibly disconnects the battery pack. All cars should have the same - a standard way to instantly shut down power.
Rampant carbon sequestration destroyed the Dinosaurs' tropical paradise. I'm here to help repair the damage.
The real icing on the cake is (as mentioned near the end) the secondary drive doesn't require a whole lot of power so it can be run by a flywheel. Infinite torque?
Except it's actually snakeoil as far as "doesn't require a whole lot of power" goes - if you read the engineering report, they conclude that the control / secondary input requires the same torque as the primary input; i.e. the power requirements are simply split between both inputs. As a result, this thing isn't actually an IVT transmission on its own at all - it requires another CVT/IVT system to regulate the secondary / control input, or a second, equally powerful source of torque, or both.
On its own, this thing is useless as a transmission, although it is a rather innovative application of this type of gear system, and would help to reduce the load on a traditional CVT system, allowing for a greater-than-usual amount of power to be transferred through the system as a whole.
Forget world peace, bring on -1 pointless
This is a re-invention of the Toyota Prius transmission. What is missing is the varible speed second shaft (with one planet instead of a full set) has to deal with torque and energy. This announcement failed to consider the transmission under load and the torque and power into or out of the second shaft. the Prius completes this torque path with a pair of motor generators.
Study a Pius transmission and then examine this planitary gear transmission. The Prius uses a full set of planets, a Sun, and ring.
His uses 1 planet (see any unbalanced mass and torque problems?), a Sun, and Ring. He notes the variable ratio just like the Prius. All that is missing is the motor generator pair to take care of the torque the second shaft requires.
A Prius is engine driven into the planet ring. The sun turns a generator (sometimes motor) and the output is on the ring gear which is fed the power generated by the sun gear generator.
His has the engine drive the planet ( notice any thing like the prius? ) and varying the speed of the Sun Gear, (the Prius uses a motor/generator to vary the speed) so the speed of the output ring gear can go from full speed, to stop to reverse (again just like the Prius).
Has the patent office looked at prior art on this? It has already been invented. The Prius version is complete and in production.
Prius calls the planitary gear system a power split device.
http://eahart.com/prius/psd/
The truth shall set you free!
So he's wearing out the gearbox instead.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
It's patented. Our generation will never see it in action.
May the Maths Be with you!
The math of the transmission (which is just a differential/epicyclic) says otherwise. Any load on the output shaft is directly transmitted to the control shaft. Basically, you can't just make energy disappear in the system. If the engine is producing it and it isn't going to the output shaft, then it's going to the control shaft.
http://lkml.org/lkml/2005/8/20/95
Er, did you not even watch the device?
It UTILIZES at least two of those.
It's not the components that are novel, it's the combination. You know, how pretty much anything beyond a simple machine is.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
This "new" kind of transmission is already available in on and off highway market for years - the concept of coupling power with epicyclic gearings is really not advanced engineering. See for example:
www.torotrak.com, on Carraro prototype http://www.youtube.com/watch?v=iDX5q-Kdw_0.
Any device which could act as a controllable speed variator (hydraulic pump plus hydraulic motor - Fendt Vario, electric generator plus electric motor - Toyota Prius, toroidal variator) may be coupled to a epicyclic gearbox in order to do "magic" things with final output speed such as ivt capability. The key is: efficiency! The simpler the gearbox, the worse the power efficiency in some working condition - i.e. in forward you may reach a 80% efficiency, while in reverse it may be as worse as 50% maximum. And please note, approaching zero speed efficiency drops to zero and every kilowatt goes to heat.
Take a look on input coupled (Torotrak) or output coupled (Prius, Fendt) solutions if you are interested in how efficiency may be raised and which drawbacks each arrangement has.
Anyway, no holy grail at all this D-Drive.
No, it doesn't utilize two; it's visually intimidating for sure, needlessly overcomplicated, but the Wiki link above points to an image which is functionally equivalent - external gearwheel, internal gearwheel; and third one (in the wiki link being a symmetrical group, not just one), movement of which negotiates the relation between internal and external.
One that hath name thou can not otter
manuals [...] are a small percentage of cars
Nitpicking: that applies in the US. In a great part of the world it is the contrary. As an example, in France, driving school and driving tests are by default on manuals. If you take the test on an automatic, you get a license saying it is limited to automatics. The times I've bought cars, the dealers never even asked if I'd prefer automatics.
In other news, automatics have reputation of being less fuel-efficient and slow to kick in when you quick acceleration. Maybe that is no longer true, but the reputation sticks.
Somehow, I don't think a transmission at 980k miles (which has been driven for its entire life in that same fashion) is going to exhibit any problems due to not clutching; it would have done so much sooner if that were the case.
Per chance he's just That Good?
~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
Yes. The two classes of epicyclic gear sets it can act as are also strictly equivalent to two configurations of a regular old differential.
The device in the configuration shown in the video is literally taking the constant main engine input and subtracting the control input to result in the output.
The engineer clearly realized that his device was just actually just an overcomplicated version of a standard epicyclic differential when only one of the control inputs is used, which is how the inventor suggests using it.
Stylish sheet to fix many problems in Slashdot's D3: https://gist.github.com/801524
GP is correct; lithium isn't radioactive, not sure why I wrote that. Was probably thinking of the limited lifespan of a lithium battery (on account of its short half-life and general instability).
But you're incorrect: lithium ion batteries have (best case scenario) a charge efficiency of 80-90%. On top of that, this efficiency level diminishes significantly as the battery pack gets "old" (ie over 2.5 years or so) or the battery pack is subjected to "extreme" temperatures (pretty much anything under 32F or over 110F). Combine this with lithium ion's cycle life limitations and their intended use when in vehicles, and you're faced with a lose-lose situation: the pack will die progressively whether the vehicle is driven or not, regardless of driving conditions or frequency of driving.
Brushless motors are a good idea, particularly when driven directly from an alternator behind a diesel turbine ICE, I think. Such setups have shown themselves to be very efficient. It's just the stupidity of using lossy batteries for the task which baffles the bejesus out of me: why could anyone with a scientific background think this is even a remotely good idea, never mind a preferable alternative to an ICE?
~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
it may increase the life of the car/machine.
Sadly, this may kill the project.
It seems that manufacturers don't want to build things that last forever. Planned obsolescence is the current fashion.
Planned obsolescence because of new safety measures, new gadgets on-board and new designs yes. Because of breakdowns, no. Perception in the eyes of buyers about how reliable your brand of cars is, can kill the sales of any car if people think your car breaks down faster than other cars. Toyota sells so many cars precisely because they don't break down (or are perceived as more robust) as US cars. In fact, it's incredibly difficult to sell US made cars in Europe because of exactly this problem. So any car manufacturer who can make his cars more reliable, in whatever way, *while not heavily impacting the manufacturing cost*, will do so.
Therefore, by the (faulty) logic you're using, you're just a cow with a keyboard - osu-neko (2604)
It actually is strictly equivalent to a planetary version of a differential assuming only one of the two control inputs is being used, as the inventor recommends.
The engineering report[1] does not come right out and say this in plain English, but it says if Control 1 is used it becomes a Class-I epicyclic gearset which is equivalent to the simplest possible such gearset, which functions as a differential between the ring and sun.
If control 2 is used it becomes a Class-III epicycic gearset. A Class III epicyclic gearset is equivalent to two simple ring-planet-sun setups where the planet(s) for each are tied together so they rotate the same. Then you hold either both suns fixed, and your inputs are the rings, or hold both rings fixed and your inputs are the suns. Either way, the output is a differential of the inputs.
So he built a really complicated differential. Nothing more, nothing less.
[1] http://infinitelyvariabletransmission.com.au/wp-content/uploads/2010/05/dDrive-Transmission-Report.pdf
Stylish sheet to fix many problems in Slashdot's D3: https://gist.github.com/801524
I really don't see why people wouldn't want to drive a stick. The excuse "I don't know how" isn't a valid excuse, except they're too lazy to learn.
The main reason I'm driving an automatic is because my wife isn't licensed to drive with a stick. An automatic is much easier to drive, because you don't need to focus on two things, just on one thing. Now I'm used to it I find I'm much more rested when arriving at home while driving in heavy traffic all the time. So for me it's a matter of safe driving and relaxed driving (which also leads to safer driving). Yes, you can reduce this advantage by then doing other stuff like makeup, etc. - but over here (Netherlands) a lot of people are doing that while driving with a stick, so it's not like stick-driving would reduce it long-term. Only at first.
As for fuel economy: I'm driving a 7-step CVT diesel (CDI), so I'm on average using 6 liters of diesel on 100 km, which is slightly better than 39.2 miles to the gallon.
Therefore, by the (faulty) logic you're using, you're just a cow with a keyboard - osu-neko (2604)
Infinite torque? Frictionless? This is almost too good to be true, there has to be some catch.
Torque is limited to the torsion yield shear of the metal, so there IS a limit on the amount of torque you can stick into any given shaft.
Max torque that can applied to a given shaft is roughly
T=(t*J/ )/r (N.m)
t=yield shear stress of the material (Pa)
r=radius of shaft (m)
J=(Pi/2)*(r^4) for a solid shaft of radius r
Basically, Tmax=0.5*t*Pi*r^3
Don't forget that we then divide that by whatever the factor of safety is! Then you also have to think about the fatigue/creep of the material etc etc
(I'm a miserable Mechatronic engineering student - someone feel free to correct me if I'm wrong!)
Yeah, a stick is awesome in a place like Seattle or San Francisco where 50% grades with stoplights in the middle are common. Nothing I enjoy more than some hipster stick-driving douchebag rolling back 10 feet into my grill.
Nothing worthwhile ever happens before noon
Yeah but eliminating clutches removes a common point of failure. So even if the performance benefits aren't that great it may increase the life of the car/machine.
For safety, you will have a clutch on it anyway - because of the new points of failure (seondary drive).
I can have a torqueflight on the ground in 45 minutes. I can clean everything and replace all friction parts in about 2-3 hours. Since anyone with a brain will also remove and resurface the flywheel when changing a manual clutch disk & pressure plate, both jobs take roughly the same amount of time. This assumes a decent-sized vehicle, which is what smart people drive. People who buy microscopic economy cars so they can "save money on gas" will eventually give it all back on maintenance because they are impossible to work on efficiently.
Nothing worthwhile ever happens before noon
furthermore, there's also the shear limit on the individual teeth in the system.
Not for windmills, generators and the like, keeping those at a constant RPM can be more useful independant of input power. It may also prove useful in electric cars, as if you can keep everything always working at it's peak efficiency you can go further on less power. There are many situations where it would be better to have a constant RPM in and a variable out (or vice versa), the question then becomes are these as easy to work with and reliable as existing gearboxes. Planetary gears, work at approximately the maximum efficiency most of the time, these theoretically can work at maximum efficiency ALL of the time.
If they can be a drop in replacement for existing tech, then I can see this taking off, if not or they require complex setups/electronics it might be a more niche product. Also how efficient this tech is, in comparison with existing systems, as if the gearbox itself is only 75% efficient, this would rule out the benefit of having an infinietly variable ratio. Pulling some numbers out of my ass I believe gearboxes are some where in the 95-99% efficient
Because removing a simple inexpensive part with a very complex one is a sure way to improve reliability and maintenance costs?
And hope nothing happens to the power supply to that electric motor while you're driving.
I suppose you could use another of these things to get an unpowered neutral, but then you've got twice the complication.
You've forgotten one very important point about the efficiency of diesel engines: they can/have to be operated at higher compression ratios, which directly translates to higher efficiency.
Why are you writing Mr. Otto's name in all uppercase?
Because batteries can be charged over-night from the otherwise idle powergrid baseload generators thus effectively using free energy that would have been wasted otherwise?
Emergency service vehicles?
What judge is going to say that it was more important to hit 35mpg than get that person to hospital?
So, the two shafts in the middle somehow affect the transmission of all that torque, but they do not need torque themselves? I watched the video & read the article, but I don't get how that bit works.
Well, maybe if you and that hipster douchebag actually knew how to drive stick properly, you'd realize that you should be using the e-break to prevent rolling back on steep hills when first starting.
Awesome job. != no clutch. Why? Because the engine is at constant speed (variable, but not variable to 0). At startup, the secondary (I assume in future implementation, electrical) drive (speed selection) will need to "spool" up to matching (let's say "secondary rod," for lack of current tech-speak) speed to provide powered neutral, i.e., no motion. If the car started at top speed then slowed to powered neutral, then it would not require a clutch. It will still require some type of detachable pad (rudimentary clutch) to eliminate power transmission until such time as the second rod is spinning (and for that matter, a tertiary rotational source to match main rod to secondary rod, until such speed as the engine can take over the load, as we do not have variable speed (reverse to zero to forward) IC engines.
Big boons: Constant speed aircraft, and if I'm not mistaken, this dude has just eliminated the need for a swash plate in high strength/volume/pressure hydraulic pumps (in real equipment, not your hydrostatic lawn mower). Probably also electric drivetrains.
To add to my previous cowardly post, a rudimentary 'after transmission' clutch would allow for spooling time, and would eliminate the tertiary power source.
Plus I wanted to add again, this thing is pretty danged nifty. Not a mental challenge to understand at all. It is a simple and elegant solution (not simple to solve, but simple to understand - in hindsight).
All you did was reword (and un-necessarily complicate) the Prius transmission. I've noticed Prius owners like to do that, perhaps to feel as if they are driving a space car, but Toyota's design is actually ridiculously simple. It's an automatic transmission, but instead of a clutch, they use an electric motor... thereby providing a variable engine-to-wheel gear ratio. Like most eloquent ideas (F=ma, E=mc^2, etc), it's not complicated at all.
And FYI, an OTTO cycle engine is not most efficient at 2000 rpm. It's most efficient at its horse power peak RPM, and at full throttle. Anything less than that (RPM or throttle), and you lose volumetric efficiency. And when I say efficient, I'm saying the power/fuel use is the maximum. It's all about the intake and exhaust design (you can tune them for maximum efficiency at a particular RPM for a particular engine design). That's why hybrids typically use smaller engines. So that you can run it closer to its peak power for longer (40hp at full throttle would be plenty to cruise on the highway and still be able to charge the batteries without needing to be throttled back).
My Beetle's a Diesel engine, not an Otto. You shouldn't make assumptions, because look what you did - embarrassed yourself. Plus wasted a lot of typing energy.
"I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
If a man isn't willing to take some risk for his opinions, either his opinions are no good or he's no good
Why wait for a full scale model to be built and tested? I didn't study the images and video very closely but I got the impression that there was sufficient information available to piece together a computer model. Doesn't one of us have some handy gear modeling software that can accurately simulate it and tell us what sort of power efficiencies we'll get and what sort of power is needed in the "control input"?
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I come from a fairly hilly area in Germany and my stick shift cars have always been fine . In fact, without the transmission "randomly" switching gears, you can reduce slippage on icy roads a lot. Rear wheel drive is more of a problem in winter...
By fairly hilly, I mean driving 10% inclines pretty much daily, up to 22% (just been up such a slope this wekend, and there's a town you're driving through).
I have had two automatics but I love - LOVE driving manual. When I'm actually purchasing my next car (sa in, last two are hand-me-down style), it is going to manual. And I'm in the USA. I also think that more people in the USA prefer manual than GP suggested, out of the people in my neighborhood that I hang out with, 3/7 drive manual. Thats not shabby at all.
This is the best comment I've seen on /. in, probably, 5 years. Thanks!
Planned obsolescence has been around a lot longer than "current fashion".
There is a story about Henry Ford - probably apocryphal, but it has the ring of truth - and the durability of the Model 'T'.
Story has it that in the 1920s, Ford sent a number of staff around the US to "beg, steal or borrow" as many scrapped Model 'T's as they could get. He then had each one stripped down and inspected to find out which components were failing and which ones weren't. The guys dismantled and micrometer-ed and recorded and collated and statistics-ed and eventually came back to Ford with a report saying, in precís, "Everything wears out apart from the flange sprocket gadgie ; we've not found one of those that's excessively worn."
"Fine," says Ford, "re-design the flange sprocket gadgie and make it cheaper and weaker. It's obviously stronger than the car needs."
Which is ha-ha-but-serious : in an ideal world, something with a 2 year manufacturer's warranty would fall to pieces, every part unusable through wear, after 732 days.
If you want something that's going to last 30, 40 or 50 years, be prepared to pay for it. An occasional acquaintance of mine works in maintenance for the electricity transmission monopoly ; the mean age of his pool of equipment was approaching 40 years the last time I stood him a pint. But you can bet that that gear wasn't brought on a tight budget from a winding shop in a distant country.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Well, yes, but all cars using this system would be automatics. Duh, it's a form of automatic transmission. Talking about how manuals have a redundant control system is dumb.
It's like someone's invented a new car where the top can open called a 'convertible', and someone says they're more dangerous because trains drive on a track whereas convertibles can drive anywhere. Well, strictly speaking, that's true...but I'm pretty certain we were talking about cars, not trains, and all cars are like that. Likewise, we're talking about automatics, not manuals, and all automatics are like that.
But, yes, manuals are popular elsewhere, although there does not seem to be a good reason for that.
Manuals might be slightly more fuel efficient if you're an expert manual driver, but I'll wager that an average manual driver gets worse gas mileage. It might have been true when people were driving around with carburetors, but fuel injection is entire different. Computers beat 95% of people in that.
As for pickup, that is, heh, sorta the opposite of fuel efficiency. If someone used to driving a manual is bitching about the pickup of an automatic, I will promise you they're getting worse gas mileage when driving a manual. ;)
But, anyway, manuals have, for almost two decades, gotten reasonable pickup. Yes, a trained driver can always get from 0 to 60 in less time than a computer...but that is a rather stupid operational test for a vehicle.
If corporations are people, aren't stockholders guilty of slavery?
Wrong. Remember how Detroit was sunk? Yeah, better quality. Today's japanese cars are functioning to the manufacturer's specifications with 100,000 miles on the odometer and they work pretty well with 250,000 miles so no: the auto industry is an all-out war and the good brands really try to build better cars. There *is* competition.
...is that they are frequently wrong.
cf. Toyota's FJ Cruiser, which gets 10% worse fuel economy with the manual transmission option vs. the automatic.
Yes, there is also the difference of the full-time 4WD on the manual vs. the part-time 4WD on the automatic, but people should bear "ceteris paribus" in mind before just blithely assuming that choosing the manual transmission option will improve fuel economy.
Most automatic transmissions contain clutches - it's how the gears are selected. Disengage all the clutches and you are in... neutral. You can coast an automatic in neutral. So you still have a redundant control pathway to control your speed (to a stop) in the event that throttle control is lost.
Even the Prius has a neutral - although it seems to be difficult to find for some drivers.
With this new box and no clutch, you have only a "powered neutral", effectively a particular throttle position.
Would this make any sense if the control motor which is a variable electric motor had to input equal torque? Then you may as well go all electric.
My guess from looking it over a bit seems to be that he is aware of the load on the control shaft. I'm thinking the ratio on the control shaft gear is such that the control is a lower ratio than the drive shaft. Therefore, his control load would be near the ratio of the 1st gear set; but I think in reverse he would have a problem??
So a large enough planet gear ratio would make his control load low enough to beat an automatic - and in fully locked mode the control could literally latch itself with a clutch or something so at its peak rpm it could use no power. (Toyota problems come to mind... a frozen control shaft forcing max output...)
Doesn't sound like regenerative braking would gain much here or am I missing something?
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Call me a nerd, but I think he should have called this thing a torque transistor. Like a transistor, it allows small torque input to control the transmission of a much larger torque. Also like a transistor, it has three connectors - the big torque in, the big torque out, and the small torque in.
And finally the one of the more important figures in gauging how effective it is its gain - the ratio of the small torque to the large one. If the gain is huge - as in a small electric motor can control the output of a great honking diesel engine, then we have a winner. It is is closer to 1 to 1, then ho hum. I wish they had said what the gain was.
Here is a different video of it. It occupies the last 1/3 of the show: http://mpegmedia.abc.net.au/tv/newinventors/vodcast/newinventors_2010_ep10.mp4 The video is actually episode 10 from here: http://www.abc.net.au/tv/newinventors/video/video.htm Two of commentators are engineers, one of which was the chief systems engineer for FedSat, an Australian Satellite. I can't imagine doing a snow job on him would be easy.
http://www.voithturbo.com/vt_en_paa_ind_varspeed_prod_varsppgvor.htm
Here is a large scale industrial version using a fluid coupling to "steal" some power from the main input shaft to run the second input. This would be one way of implementing the option of powering the D-drive with some of the engine's power.
I think the simpler version for light duty or automobile would be to use electric power.
Generally the second shaft takes about 20% of power of the main input shaft, so not that small if I recall correctly from the vendor presentations. These are an option to electric variable frequency drives for large 3500hp pumps in my industry.
Nitpicking: That applies in Europe. In the US nobody except car aficionados even cares about reputations for fuel efficiency or acceleration.
Actually, the two transmissions I was referencing were for the 2000 TransAm.
The automatic is a 4L60E. It's shipping weight with torque converter is 176 lb
The manual is a Tremec T56. It's shipping weight is 75 pounds.
The remainder of the additional weight is a matter of the difference in equipment required for the different transmissions. The manuals get a rather light shifter bolted to the top. The automatics get a floor mount shifter and linkages. The manual does not require any additional cooling, other than the few quarts of gear oil. The automatic requires quite a bit more fluid, piping and exterior cooling. etc, etc, etc.
I didn't know there was a difference until I registered my second one. One was an automatic, and one was a stick. My state taxes (yearly registration) based on the weight of the vehicle. I then took both vehicles as it would have been delivered from the factory, both with full fuel tanks, and yup, there was a 300 pound difference.
Serious? Seriousness is well above my pay grade.
Actually, those were suppose to be separate statements. Sorry. :)
A lot of cars (regardless of their transmission) couldn't navigate the hill due to lack of power.
4wd vehicles usually have an advantage of a 4L gear (4 wheel output, lower gear ratio).
Of vehicles of equal rear wheel horsepower (including overall gear ratio), they are equally drivable, if the driver of each knows how to operate his vehicle.
A slipping torque converter can be a significant cause of transmission overheating, so although it may seem like a momentary advantage, it's a long term (and expensive) disadvantage.
Serious? Seriousness is well above my pay grade.
So you think the reaction torque is different than the working torque? Do you even understand the definition of torque? Torque is the effective radius multiplied by the force. Your reaction shaft might be geared lower so that it doesn't require as much force to push, but its the lower gear has a smaller effective radius. These two things negate each other and you still end up with the same torque. The only difference is the speed of your output. A higher output RPM is balanced by the reduced force which results in the same torque.
It also removes a redundant control method.
Throttle stuck ? - stamp on the clutch (and the brake) no problem.
But if such a secondary control method is needed (I assume you meant as a kind of emergency stop procedure), why couldn't you simply turn the engine off and stamp on the brake? Sure, you may lose power steering or whatever other important gadgets are assisting drivers these days - but we are talking about some extremely rare emergency anyway. Of course that won't work if your key broke off in the lock or whatever, but hey, what if your throttle AND your clutch gets stuck...
Stop-and-go traffic in Los Angeles, on the 405//110 freeway. I know people who commute daily on these freeways, in a manual car. They end up with carpal tunnel, arthritis, and other complicated medical problems in their hands and wrists.
"This is about the age that an automatic transmission would need to be rebuilt. For this car equipped with an automatic, removal, rebuild, and replace costs about $3,500."
BS. Automatic Transmissions can go well beyond 200k without having to be rebuilt, it just depends on the driver. Bad driving will trash the AT and cause it to fail early on. $3,500 is a fools price for a rebuild. The last time I had to get an AT rebuilt, it cost me $1,500, and it's a price I'll gladly pay for the sake of healthy hands/wrists(which I work with), and my sanity while driving stop-go down a congested freeway.
Depending on the limits of the gear ranges available, you may be able to stall the engine and/or slow the car to a crawl by shifting appropriately.
Japanese cars can easily last 10+ years, as can many Korean ones. They just rely on people not wanting to drive a 10 year old car.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
My car with a manual gearbox needed a service recently, and I checked out the manual for the transmission fluid change intervals, and it said "No need to change apart from specific conditions". I checked out the service manual and it confirmed this, the transmission fluid never needs changing apart from really specific conditions which don't occur in normal life. In fact, to change the fluid, the mechanic has to drill into the transmission (there's a specific drill point) and drain it - there's no drain plug, it's completely sealed.
In theory, you should never need to replace a clutch if you drive it right. There's a source, but I can't find it right now.
My dad and I drove a manual car for 140,000 miles (total 150,000 miles from new) and it still had its original clutch before I sold it. It was *just* about starting to slip, though.
My current car has 100,000 miles on the clock, and the clutch is still in top-notch order (whereas the suspension isn't!).
Anyway, clutches are dead cheap to replace, on the first car I mentioned (the 150,000 mile one) - a new clutch costs £80 (about $120) and all needs to be done - release a few bolts, and it slides right out (no need to release or move the gearbox at all) and the new one slides right in and job done. My new car is a little bit more complicated than that, however.
Good point. I wish everyone in the U.S. was made to become proficient with a manual. They're simpler, cheaper, have better performance, and last longer (the last one is my subjective opinion based on being simpler). Depending on your driving habits, they may get better mileage. In a pinch, you can push-start a manual on a dead battery. Now if they could only create a manual that would become automatic in stop-and-go traffic - that's where an automatic is preferable.
I'm also tired of the rest of the world getting manual transmission options on more cars than we do in the U.S. That and we get fewer wagon and hatchback options.
I'd think it a 50/50, really.
They rely on some people driving a ten year old car, telling their family and friends, "Damn, my Whatchama Callit is so reliable. All I've ever had to replace on it was a couple of tires from running over a tie bar in the middle of the road. Other'n that, regular maintenance keeps 'er purrin'. Y'know. Oil, spark plugs. Rotate the tires. Change out the belts every 40,000 miles. That stuff."
The result on that would be people swayed to head over to the Whatchama dealership when their Fickser Errydamday breaks down every damn day, and they're tired of fixing it. Granted, they might not pick the Callit... but they might've spent the extra dosh up front to buy a different Whatchama (maybe they needed a pickup instead of a sedan) after hearing (and in the case of the ten year old car, SEEING) about the brand's reliability.
That ten year old car's not on the lot, but plenty of new and gently used ones that are perhaps a year or two old are there.
Getting that into a new buyer's hands is the important part, to them.
If you need real brands, substitute Vespa or Peace for Whatchama, and Wildfire for Fickser.
'cause I'm about to buy a Peace for myself. Sick of repairing that Wildfire every month because something new happens.
My numbers aren't off at all. A new clutch disc (friction disc), pressure plate, and slave cylinder for my truck ran me $200 when I replaced them 5 years ago (I've since sold the truck... and now I miss it). Out of sheer curiosity, I researched pricing on auto trannies for the same truck; I was able to get a rebuilt for $2000.
I never mentioned labor because I did the work myself.
APK quotes people (including myself) without context and should not be trusted. Just thought you should know.
What concerns me is that you need a secondary motor to control the gear box.
It is not clear to me from the video, that the reverse torque is not completely coming from the secondary motor.
Have a look at the DSG gearbox from VW/Audi/Porsche. It's essentially a double-clutched manual w/ an automatic shifting bit.
http://en.wikipedia.org/wiki/Direct-Shift_Gearbox
Don't think there's an equivalent in an ice.
Sorry, but if you read the followup to the article, you'll see it's pretty much the Prius transmission:
Doesn't bother me at all. If you have weak legs, or don't know where the neutral is on your manual I can see you having issues though. Now I will say, it can be pretty touch and go in snow, I have a very narrow band between stalling and peeling out, and it only gets worse with adverse weather.
APK likes to ask for responses to the same things over and over. Maybe he just likes the responses?
I'm not sure about the batteries in hybrids, but lithium-ions optimized for efficiency are about 90%. Coincidentally, batteries optimized for charge efficiency are also optimized for charge time, since less heat is generated while charging.
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Sorry, I thought you were talking about regular reciprocating engines. Yeah, turbine -> generator -> motor is a great idea, at least until we find a long lasting, fast charging, high capacity, inexpensive battery chemistry. Which will probably be a while.
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$3,500 is about average for a transmission built with R&R. If you're doing the labor, it may cost less.
Some transmissions cost significantly more. Total for my ex's Honda CR-V was $4,800. That wasn't just us getting ripped off. I had several mechanics trying to source one for cheaper or even a used one, so they could get the job instead. That particular transmission only showed up in a single model year, and only on the Honda CR-V. As always, the less common the parts, the more they cost.
Serious? Seriousness is well above my pay grade.
Sorry about that. Most people don't do their own work, so I assumed what others very likely did. I should have realized that. I get the same thing a lot. I haven't done my own clutch or transmission for a while though, usually because of either time or tool constraints.
Ya, 10x the amount is an awful lot to pay for a regular maintenance, even if it is every 100k miles or so.
Serious? Seriousness is well above my pay grade.
I know it's possible to mistake what gear you're in. It's usually an unfamiliarity with the vehicle. In my car, it's easy for someone who's unfamiliar with it to do that, or put it in the wrong gear. I replaced the stock shifter with a "short stick". It's only a couple inches lower, but doesn't require me to move as far to shift the gears. That was partly for performance, and partly because I'm lazy. :)
I've seen people who forgot that they shifted an automatic, and done it again. It's not so bad in reverse, if you only make the mistake once. One click to reverse. The second one goes to neutral, so they just don't move. I've also seen the same mistake in drive. 3 clicks to drive (4th/OD). 3 more to 1st. Then they get all confused about why it'll only do 20mph.
I'm sure you've heard people start their car twice too. You know, that unpleasant sound where the driver turns the key again after it's started, and the starter gear jams into the flywheel rather than engaging it (since it's spinning).
People do stupid things, because they aren't paying attention, or don't really know what they're doing.
I've never seen a study on what people drive, I only know from my observations. Probably now that we're discussing it, someone will base a thesis on it. :)
Serious? Seriousness is well above my pay grade.
You've just reinforced my point -- that most people can (and to a certain extent, DO) drive on auto-pilot. It's why they have the brain CPU cycles left to do things like navigate, get in the correct lane, know that the light up ahead is most likely NOT going to stay green, etc. This is not limited to automatics, it works every bit as well with a manual. My point was that once you get the mechanics of driving down to the point of doing it on auto-pilot, mental illness is not going to strip you of that ability. It doesn't matter if you drive an automatic Civic, or a 10-gear Peterbilt.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
What no one seems to have noticed is that transmissions are not just for efficiency and rpm limits --- you get a mechanical advantage from torque multiplication as well that you lose out on with a fixed planetary gear system. Though you might be able to combine something like this with the multiple planetary systems an automatic transmission uses, to get continuously variable in->out with a select set of torque ranges.
You should be more disappointed by the lack of mentioning of Nazis.
It's not insane to not want to shift through stop and go traffic on hilly roads. A decent compromise is the 5-speed manumatic cars.