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Electronic Valves For Diesel Engines
Anonymous Coward writes: "EETimes describes how electronic valves will replace camshafts in diesel engines starting in 2007. Lower emissions, better performance should follow." This wouldn't be a bad idea in gas engines, either. There's potential here for low emissions, better gas mileage, and greater performance, all at the same time.
"...electronic control will enable engines to change valve timing on the fly..."
Why, it's a run time optimizing just in time combustor!
This will never happen. Car shops make millions every year adjusting the timing belts that currently drive the camshaft for the valves. If a computer were to control the timing, it would never need adjusting. Not to metion the fact that this would put the companies that make those strobe lights that you use to check the timing out of bussiness.
On the other hand, this makes herf gunning (or worse) a car all the more fun.
Daniel
It will be a long time before these engines will be as reliable as cams and pusher rods. Not to say that is isn't a good approach, but nothing electronic functions very well when it is -40F here, and I have no reason to expect that these engines will be an exception.
And what exactly happens in a high compression engine when a valve sticks in the open position and the piston comes home? Nothing good!
Dog is my co-pilot.
Allright, we've let the computers control the ignition (and all the stuff inside the car) but fuck me I don't need no virtual cam shaft. Future quote "I'm sorry sir but it looks like your autocam chip fffft-up and your engine is now toast. That will be $200 for the pistons, $600 for the new cam and rods, $300 for the port and polish, $100 for the new cam chip and $2000 for the Microsoft Virtual Cam package. Will that be credit or your first born?
Cha...ching!!!!!!
I'll take a 68 mustang fastback any day over any of these new cars!
no sig.
Sadly, it would appear that asthma is effected more by the particles shed from automobile tires than from exhaust. The new high-strength "rubber" makes particles much different from tires 25 years ago. This would explain the recent increases in asthma.
Dog is my co-pilot.
Subject says all ; their prototype "camless" engine is already running. Basically, they use electric actuators instead of the usual cams. And since the engine's electronic already handles fuel injection and air intake... it's just one more parameter.
Camless engines are routinely used in economy races such as the Shell marathon (run as long as you can, with a single litre of gasoline)...
What's going to really rock is HDi (or GDi) + Camless + alternatmotor (basically, you replace the smaller alternator + starter combination by a bigger dual-use electric engine/alternator, which allows to give the thermic motor a boost when accelerating, allows stop-and-go when you're stuck on the Périph's monster traffic jams (zero emission, then, and zero noise). Unfortunately, that means switching the car's electric circuit to 48V at least).
And that's going to be much sooner than 2007 !
(Besides, Diesel in HDi + Anti-Particle Filter is much more efficient than classic unleaded ; Diesel is easier to refine, and gives a little more energy per mass unit. And direct injection gives the level of control necessary. See whan Peugeot does with Bosch injectors, it's just really amazing).
Yet another example of how large corporations become inefficient after they reach a certain "breaking point" size.
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CAIMLAS
~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
I have the original version of that diesel engine you speak of. VW calles it the TDI. Turbo Direct Injection. It uses fuel injectors mounted in the combusion chamber wall, removing the intake valve entirely.
My '96 TDI Passat has an inline 4 at 1.9 liters and is rated at 43 mpg highway. The car is significantly heavier than the Golf, so the difference isn't a big surprise. I've actually gotten up to 47 mpg highway going 55-65 mph. I usually drive about 80-90 mph on highways though, and the mileage drops to about 38 mpg.
The engine only puts out about 95 horsepower, and redlines at about 4250 rpm. But it does have quite a bit of low-end torque, 150 ft-lbs at about 2000 rpm. Don't get me wrong, its not a fast car by any means. However, it does decently against most other 4 cylinder sedans.
The later versions of the TDI engine are more fuel efficient and have better performance too.
I've heard that VW had a 5 cylinder version available in Europe and is working on a V6 version. The TDI has been selling rather well in Europe, as gasoline prices are very high there. In the U.S., there aren't so many.
The reason that the car runs efficiently is that the direct injection allows the spray of fuel to be directed and controlled. A bowl-shaped cutout in the head causes the fuel to swirl in a heavily-concentrated area in the center of the cylinder while at the edges there is less fuel. The better overall fuel-air ratio is what makes it more efficient.
The reason that one can't normally achieve the ratio is that the fuel wouldn't ignite if it was evenly distributed at that ratio. The swirling of the fuel allows the ratio at the center to be enough to ignite, while that at the edge brings the overall fuel-air ratio down to more efficent levels.
I believe Mitsubishi or Toyota is experimenting with direct-injection gasoline engines. Anyone know how their progress is?
Using your sig line to advertise for friends is lame.
Cam-shafts and electronic valves indeed! My trusty RX-7 needs neither. Rotary engines rule...
"The best we can hope for concerning the people at large is that they be properly armed." - Alexander Hamilton
> you now have to worry about the engine itself
:-)
> crashing
Technically, you have to worry about that now. Damn near ever single car manufactured in the last decade has electronic fuel injection and spark control. Embedded microcontrollers take into account their increasingly important role in the overall system when designed. They're written to *not* "crash".
> but the crankshaft works so well
Actually, nobody wants to replace the crankshaft, just the camshafts. The problem with a typical camshaft design is that it fixes the cars valve operation profile throughout the entire RPM band. That's extremely inefficient. A standard 16-valve engine running at 7000 RPMs requires a dramatically different camshaft profile than one running at, say, 1500 RPM for maximum efficiency and power. By making valves electronically actuated, you allow the ECU to adjust *everything* automatically for peak operation. Sounds good to me, I just don't wanna be the one to mess up that tight timing code...one good bug would cost a company millions in new motor replacements.
Thomas Dorris
The difference is: In the VTEC engine there are only two different valve timings. It is not continuously variable as an electronic valve system would be. Why? Because there are no electronics in there. The camshaft has two cam profiles for each valve. Below about 4000rpm one cam profile is used, when the revs get past that, hydraulics push the cam shaft sideways and the other 'high performance' profile is used. Thats why these things are so reliable. Honda offer a 100,000 mile warranty on the engine and they have never had to repair one under warranty.
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In Truck and Car (used a lot in cars here in europe) applications this might be no bad thing, so long as they get it right, camshafts are a very well developed and understood technology.
But one of my fathers favorite stories is from when he worked for British Gas (Note for American speakers, here I mean gaseous gas, not petrol). The Thames river in flooded, flooding the gasworks. They got a boat and paddled rounbd the site to the pumphouse, where the big diesel pumps were still chugging along, five feet underwater, keeping the gas pressure up and preventing the pipes flooding, just as they were designed to.
The point is that the pure mechanical nature of a conventional diesel is a advantage in some situations. Offroaders often like them for their power characteristics, but also because they are very tough compared to petrol units. Similar in boats, you can get away with immersing them in a warm salt mist, that would eat any electronics not immensely shielded, and get away with it.
EZ
-'Press Ctrl + Alt + Delete to log on..'
"Oops, I always forget the purpose of competition is to divide people into winners and losers." - Hobbes
I have a silver-blue 1966 Ford Mustang coupe complete with a V8, dual exhausts, and a Pony Interior. My dad and I restored it ourselves when I was in high school. It's in great condition and I can safely say that it is the best looking hard-top Mustang I have ever seen anywhere.
I love my car dearly. But as much as I love it, we are going to have to get rid of it soon because having a car like that just isn't practical. Sure you can fix it yourself, and the abundance of reproduction parts means that you never have to go through dealers. So it seems that you can save a lot of money this way, right? Wrong. I have never heard of someone being able to save money by driving a vintage car. They are mechanically simple (you can open the hood and see through to the ground), but a consequence of that is that they are VERY POORLY ENGINEERED. If you have options like power steering and an automatic transmission, you'd better be ready to spend a lot of time lying on the garage floor with a wrench in your hand. Any money you save on labor and parts you turn around and spend on more tools and stuff.
Someone said once that Linux is only free if your time is worthless. You can say the same thing about DIY auto repair. If you work for X dollars per hour, then DIY repair only makes sense if you earn less than the mechanic charges for labor.
We're probably going to replace the Mustang with a Japanese car, like a Toyota. We have had several rice-burners over the years, and we don't even care that we can't fix them ourselves because they simply never need to be repaired. They were built right from the beginning, so they run forever on nothing but gasoline and regularly scheduled maintenance. We've never had any weird problems with any of the Toyotas we've had, and we put almost 200,000 miles on one of them.
Oh yeah, did I mention that they get over twice the gas mileage of the Mustang? They don't require the expensive 93 Octane gas either.
In short, simplicity isn't a virtue when it comes at the expense of functionality and reliability. Furthermore, something as incomprehensibly complex as a modern automobile doesn't have to be unreliable, provided that it was done right from the beginning.
The complexity of cars will continue to increase dramatically. Gas in South Carolina has doubled in price in two years, and if this continues, people will simply need the fuel efficiency.
Oh well -- I don't have time to finish, but I hope I've said enough so that my point makes sense.
Gotta run,
Steve
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Stephen C. VanDahm
The idea is quite old now and I actually saw a working system demonstrated at Lotus a good few years before Colin Chapman died. It was used to help design camshaft profiles. You could even use a 'light pen' to pull the curve as the engine operated in real time.
BTW it definitely was electrohydraulic.
The patents system is sick, it really needs a overhaul. Here is a system that could have been implemented years ago and saved millions of gallons of fossil fuels from being wasted. What are future generations to think of us.
threadeds blog
...major improvements in electric engines.
One of the big bitches of electric cars is (besides battery life) the poor power/weight ratio of the electric engine against the gas (petrol) engine. Also, even more damning, is the relative reliability of the gas engine. What we really need are people putting alot more effort into making a better, lightweight electric engine.
We already have the parts to build a really good hybrid gas/electric car (which, face it folks, is the only kind of low-emissions vehicle you will see for years). We have the following parts:
The Honda Inspire and the coming competition from Nissan and Toyota are OK, but face it, we need something about the size of a Honda Accord, not a Honda Civic CRX. I can't see any reason (technically) right now why someone doesn't mass-produce a converted Accord. I mean, you can use the exact same design (maybe cheat and use alluminium body panels), just with a new powertrain (with an electric engine, you should probably have a continuously variable transmission, rather than an "automatic", and definately not a "standard") and still get at least 70+ miles/gallon (that is, 30km/l).
Hell, with the $4k US tax credit for buying a low-emission vehicle, and gas here at $1.85 in the Bay Area, I'd spend $5k more for a converted Accord over a normal one, and still make out like a bandit. So who're the morons in the Marketing Depts at the car manufacturers?
-Erik
There are always four sides to every story: your side, their side, the truth, and what really happened.
I've seen a 28V electrical system in military vehicles, to power radio equipment.
Mea navis aericumbens anguillis abundat
I have had my VW Golf TDI for one year now, and I am going in for my 20k service this morning. :)
I am really impressed with the mileage. It uses less fuel, needs no tune-ups, is more efficent, and will last twice as long as a gas engine.
VW is also producing a 150 hp TDI with 250 lb ft. for all the diesel naysayers.
It really is the best choice for the enviroment.
...my car is also Abt/Yokohama/Koni/H&R kitted, which makes it a bit more fun
F1 uses pneumatics (for almost a decade, I believe).
<p>
The reason why an electromagnetic system is not used in F1 is that current F1 engines rev up to 18000rpm and the current system don't work there yet (I believe BMW has a system that works up to 6000rpm.
I can report with confidence that my car, which has electronic injection and ignition, has not crashed in the 4 years and 100,000 miles that I have driven it.
We have already started infiltrating our engines with electronics, and with good results. My midsize sedan gets 30 mpg with all the power I could want. Even back in the stone age days of '96 when a Pentium-166 was a fast computer. In fact, the only things that have needed replaced/failed on my car are pesky mechanical crap: brakes, struts, etc.
Do not confuse the reliability of your desktop PC with the reliability of embedded systems. They are structured and developed very differently, with an emphasis on reliability.
I just read in the last few days about a rumor that Renault is developing an electronic valvetrain for use in 2001. I've been unable to find that article now, otherwise I'd have posted the URL. Renault just bought the Benetton team in the last few weeks, and I'm sure they are keen to find an edge to fend off the other big engine manufacturers involved in the series.
Honda gives you two cam profiles, but there are some others with even more flexibility. Porsche used a chain they could adjust the tension on to change when the cams engaged. My favorite, though, is the Ferrari V8 system: a shaft with long, tapered cams, so you can push it in or out to get the total range of timings.
If you've got an interest in engines and can stomach a few equations, I'll go ahead and plug my professor's book: Engines: An Introduction by John L. Lumley.
that if your electronics glitch, your engine won't run poorly... it just won't run.
Then there will be the car running on an MS O/S. Needs to be rebooted at least once a day.
Gonzo
If you think that riding a tank full of volatile, flammable liquid is bad...
How about riding a massive wheel rotating at well over 1000 revolutions per second, where any failure of the magnetic bearings results in all that energy being released instantaneously?
Sure, flywheels are cool and efficient, I might like one in the basement instead of a UPS, but I sure don't want to ride one.
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Stop worrying about the risks of nuclear power and start worrying about the risks of not using nuclear power.
Are they sure we will still have anything to put in our tanks by then?
Short answer: YES
Long answer: There will certainly be gasoline in 7 years. The middle east is sitting on vast reserves of oil, IIRC more than enough to last us 1000 years at current demand. The former Soviet union has huge amounts of petroleum, and you can bet that the big oil companies are investing huge amounts of money into infrastucture and production there, so they can export that oil, too. The US isn't operating at anywhere near it's full potential for oil production; there's no need to, it's cheaper to import petroleum from the middle east than to produce it here. The question is if it will be cheap enough for Americans to keep driving like we do now.
0 1 - just my two bits
"Lots of power" and "high MPG" are mutually exclusive goals. Vehicles that need to be capable of doing *real work* like hauling 40 100lb bags of cement or pulling the boat to the lake, or a house trailer camping, or a horse trailer to the ranch, or a water tank need to be EXEMPTED from stupid smog regs. This exemption must also *not be confined* to "commercial vehicles" or "commercially owned vehicles" as many *individuals* have need to do this too. Maybe a 70MPG Honda Imprevia is good for all your needs, but some of us need more. And it's not just "waaay out in the sticks" either. I live in the Stonehurst area at the top of the San Fernando Valley area which is a low-density ranch area (zoned for horses) smack in the middle of metropolitan Los Angeles. No 70MPG vehicle will carry 3000lbs of feed. Now I hear Calif wants to impose car emmissions requirements on trucks and SUVs? WTF?
Well... yeah. So? :-)
It's just like Linux kernel junkies & overclockers...they're too busy futzing with the car & preening over its technical specs to realize they're not actually getting anything done.
Oh, come now! Overclocking and kernel tweaking are fun. Having fun *is* getting something done. And if you have to drive (a regrettable necessity of most modern folks), you'd might as well have some fun doing it. I can think of no purely utilitarian reason to interest yourself in your car at all.
What is it with geeks & RX7s? They gotta have the "superior" technology that's barely competitive in the real world with piston engines..
Untrue, but let's save ourselves the argument and quit here. I think rotaries have great potential for non-sports cars.
and Im sure the big-peepee styling is a major selling point, too.
Personally, I wouldn't mind a rotary VW Bug, or some other not-quite-so-macho car. It's the engineering. RX-7s are really good, technically interesting cars.
Not to mention that the 1st & 2nd gen RX7's are a cheap ticket into sportscar land.
True
Pity they couldn't do any better than a Porsche 944 ripoff for the 2nd gen styling though.
I agree. 1st gens are much cooler.
I actually wouldn't mind a rotary-powered Miata..that'd be a cute grocery getter to toss around..
Ahh... the truth comes out! Rotary envy! ;-)
I've always (ruefully) wondered why they went with a reciprocal engine for the Miata.
"The best we can hope for concerning the people at large is that they be properly armed." - Alexander Hamilton
I had my 89 crown victoria tuned in 1990 when I moved from sea level to Vegas--the manual said it was due, and I'd just moved to a higher altitude. That was at 30,000. 30,000 miles later, I took it in again, as the manual said it was due. They charged me about $10 for looking at it, and gave it back, saying it had absolutely no need for a tuneup.
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I've now gone almost 10 years and over 100,000 miles without a tuneup. But there's really nothing left to tuneup on these things--check and see if the spark plugs are fouled, replace any broken spark lines, and make sure the computer hasn't reset itself. My mileage is unchanged from back then, so I have no intention of taking it in any time soon . .
It wasn't for a couple of years after they built this one that they started advertising about 100,000 between tuneups . . . and they probably don't need that, either . . .
I think that because of the battery weights, the older bigger styles of cars may be better targets for diesel-electric hybrids. You have to haul a lot of battery with the current technologies.
Check out the US Army HumVee project here and a little more information here. Several minutes of dedicated web searching should turn up more informative links, but hear's the gist I remember from news stories:
- The original point was to reduce IR and noise signals, in particular to not have a good IR signal for a missile to home in on (but don't those electric motors get really hot ? anyway . .
.) - The batteries in the bed of the vehicle provided some protection from large anti-vehicle landmines (this might be wrong, I'm remembering it, it wasn't in the linked stories above)
- It could climb a steeper grade due to the weight of batteries lowering the center of mass
- Better fuel mileage
- better acceleration (I was surprised to learn that most electric motors can accelerate a car pretty well, if the car isn't loaded down with batteries to give it a decent range)
- smaller payload due to all that battery weight
I would hope to see fleet vehicles like the postal service trucks or delivery trucks like UPS/FedEx start using this technology.I have wondered what kind of diesel generator they have. I wonder if you could do better than a piston engine with a small turbine whose rotors or blades were permanent magnents forming the armature of a high-speed generator.
Anyway, I would not mind having an econoline van with this type of setup on a smaller scale.
One in Four children in Australia have asthma ... think what you are doing to kids health before you drive that short distance down the road
And one in 5 of thouse kids smoke too.
When I was doing some stat work for a asthma reseach project I found that 90% of all children with asthma were exposed to smoke at least onec a week. The inital surveys answered by their parents showed only about 10%. Thouse that weren't exposed to smoke had problems with either pets, molds, grasses or very rarely foods. I visted a few houses where kids had problems with chemicals. One house had a mould smell so bad I couldn't breath but one of the cleaners the mother used would set off the kids asthma within a few hours. When the kid was taken away from the envioment the cleaner didn't cause a problem.
So is rubber or diesel a problem for people with asthma? Maybe or maybe not. With any substance you can find someone somewhere that will be effect by it.
I have a feeling that none of this will matter until someone works to remind the average luser that what they "know" about diesels is wrong. It seems that by far the majority of the American populace thinks that diesels are more expensive, slower and less reliable, none of which is true.
Right now, the diesel manufacturers seem to be pulling an IBM. They have a better product but seem allergic to actually advertising it. The timing is perfect for a strong ad campaign right now while the US gas prices remain higher than normal ("Wondering why guy who passed you was smiling? His car only needs a fillup once a month and it was cheaper, too")
[1] In practive I significantly outperform the sportier vehicles as well, but that's a function of the rather bovine drivers that are so common in San Diego: "Whoa! The light! It's green! It's been green for 30 seconds! Ooops, almost stepped on the gas ahead of the rest of the pack. Mustn't get out of line! Listen to that rude driver honking at me just because the light's turning yellow now. He'll only need to run the red a little!"
(In other words, slower hardware + good software > faster hardware + lousy software)
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I seem to recall that a Golf direct-injection diesel racked up something like 90 MPG in a tour of England some years back. Running at a cruising speed of about 50 MPH and with the lack of throttling losses inherent in the diesel, plus the reduced heat losses of the DI configuration, the only thing that could potentially beat it for efficiency would be a fuel-cell vehicle, and it might take a fuel feed which doesn't require a reformer (which loses efficiency) to get there.
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Time is Nature's way of keeping everything from happening at once... the bitch.
There's an Australian company called Orbital which pioneered an air-powered gasoline injector for direct-injection 2-cycle spark engines. Mitsubishi et al. may have drawn some of their inspiration from realms to the south. I know the Japanese don't own the field; GM was testing a 2-cycle engine for a prototype mileage-champ vehicle some time ago. The killer was NOx emissions due to the lean-burn mixture; the engine could not meet EPA specs.
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Time is Nature's way of keeping everything from happening at once... the bitch.