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How Chrysler's Battery-Less Hybrid Minivan Works
thecarchik writes "Chrysler announced Wednesday that it would partner with the US Environmental Protection Agency to build and test prototypes of a different kind of hybrid vehicle, one that accumulates energy not in a battery pack but by compressing a gas hydraulically. The system in question, originally developed at the EPA labs, uses engine overrun torque to capture otherwise wasted energy, as do conventional hybrid-electric vehicles. The engine is Chrysler's standard 2.4-liter four-cylinder, the base engine in its minivan line. But rather than turning a generator, that torque powers a pump that uses hydraulic fluid to increase the pressure inside a 14.4-gallon tank of nitrogen gas, known as a high-pressure accumulator."
This sounds like an excellent alternative to explore, but I do wonder how that 5000 PSI reacts when crushed in an accident. CNN describes the tank as a "bladder".
FTFA:
That compressed gas, stored at pressure as high as 5,000 pounds per square inch, represents energy waiting to be released.
Not sure I'd want to be an a 1.0 version consumer vehicle with that much pressure without some serious discussion about the safety precautions to prevent or mitigate "unexpected pressure drops".
Can someone who's got more experience with the fluid mechanics add to this?
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Try working on a vehicle with a 5000 psi tank inside.
I eat only the real part of complex carbohydrates.
The amount of energy you can store in a 14 gallon hydraulic accumulator is pretty small. Even if they're cranking the pressure up to 6-7,000 psi the energy density is around 50kw-sec/gallon or somewhere around the equivalent of a car battery.
There is a theoretical limit to how efficient a compression/expansion 'battery' can be.
I don't recall the formula, I'm sure some /.er with more recent thermo then I will come up with it.
I do recall that to get decent efficiency the high pressure side needs to be very high pressure.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
...spring instead?
Generators cause drag so you loose some energy but this type of system would add friction into the mix which would waste more energy. Seems more like an energy shell game with looses from friction along the way.
Why is it that this system would necessarily waste more energy than a electrical system? You say that this system would add friction, which is just another word for the "drag" that the generator adds in an electrical system. Why is this more of an energy shell game than an electric hybrid? It's just replacing the generator/battery combo with a compressor/accumulator combo.
Assuming that it's mostly a short-term compress/decompress cycles, as long as the accumulator is well insulated to prevent heat loss, it should be fairly efficient. Perhaps more efficient than a battery.
This article suggests that a hydraulic/compressed gas system can have 75% energy recovery for start/stop conditions as compared with 15 - 20% for a gasoline-electric hybrid:
http://www.scientificamerican.com/article.cfm?id=hydraulic-hybrid-vehicle
Perhaps not pointless. In the city, it's the start-stop aspect which is the mileage killer. Regenerative systems capture some of the energy used to decelerate, and use it to re-accelerate later. This is responsible for a large part of the efficiency of electric hybrids in city usage. I'm not sure if the hydraulic system described in TFA is linked to braking, or would by nature of its design capture energy during deceleration, but if so it would definitely help in city use. In fact, that may be the only place in which it shows gains, but let's not underestimate that. Most minivan use IS city use.
There is also the advantage that it's not based upon rare earths or lithium, which have their own political "sourcing" issues and their own limitations on how much is available. In short- to medium-term timeframes, that could be more important than ultimate efficiency comparisons with electric hybrids.
The safety concern is a serious one. Unlike present applications mentioned in TFA (garbage trucks, busses), there is much less structure in a minivan-sized platform to protect the pressure vessel. Anyone remember the Pinto problem? This is solvable, though it will require more structure (meaning more weight) to protect it. Overall, the hydraulic subsystem + the weight of the protective structure are probably less than the weight of the electric subsystem including its batteries, so that may be a net gain over electric hybrids, but we won't know til we see specs.
Everybody gets what the majority deserves.
FTFA:
That compressed gas, stored at pressure as high as 5,000 pounds per square inch, represents energy waiting to be released.
Not sure I'd want to be an a 1.0 version consumer vehicle with that much pressure without some serious discussion about the safety precautions to prevent or mitigate "unexpected pressure drops". Can someone who's got more experience with the fluid mechanics add to this?
Scuba divers drive around with aluminum cylinders containing air at 3,000 PSI. Safety "burst" discs are built into the regulator of the cylinders so that if over pressurization occurs they rupture. The results are frightening and embarrassing but its only air and not shrapnel since the cylinder remains intact. I expect there are similar technologies in the pressure vessels in these cars.
So if I can't start my engine and my pressure tank is empty, how do I jump start it? Connect a high-pressure line from another vehicle with the same kind of accumulator? Or do I have to tow-start it?
As far as I have seen there is no future in compressed air vehicles*. Possible efficiency improvements are predictable, and nowhere near the point where anyone should be developing prototypes.
It comes down to this being a morally corrupt waste of money.
*Fixed site to site vehicles (trains and similar) can feasibly use compressed air, however the fuel options for these systems is quite large and can reach much higher efficiency.
I routinely work with compressed gases (~2500psi, medical oxygen on an ambulance). The tanks are tremendously well-built, and if you drop one you're worried about the valve because it protrudes - not the tank itself. And by my envelope calculations, there's something like 603k pounds trying to turn my tanks inside out.
Yes, I'd want to be damn sure I knew what that tank was doing, and how well it was built - but we're pretty good at making pressure vessels that won't rupture on their own, and equally good at making ones that are solid enough to withstand impacts.
Frankly, 15 gallons of gasoline worries me more. The kind of impact that would rupture a tank would aerosolize the gas, and I'd rather be in an explosion than an explosion with fire.
I have developed a truly marvelous proof of this comment, which this signature is too narrow to contain.
So, in short, you are ok with riding with 20 gallons of highly flammable liquid but you are afraid of 14 gallons of compressed air?
Batteries and liquid fuels have the huge advantage that when they blow up, most of the energy is released as heat.
I dunno about you, but 99.9999% of the world's population considers that to be a very serious DISadvantage in an accident.
If the pressure cylinder can be held in place, then the sudden, explosive release of an inert gas, such as Nitrogen, might actually be of some value in an accident. Fire suppression, perhaps?
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Generators cause drag so you loose some energy but this type of system would add friction into the mix which would waste more energy
A bigger engine with 2 extra cylinders (to match the performance of this 4-cylinder hybrid) also adds friction, and it does so all the time the engine is running.
I would assume that this gas compressor can be disengaged with a clutch when not needed, so the friction losses could actually be less overall for the same max power output.
I don't believe it's quite the same thing, but this group has been working on a similar idea for a few years now. Only problem is I don't think the latter vehicle would be so splendid in the snowy North.
I've seen tires from semi's explode, and take peoples hands, fingers, and critically injure them if the rim shatters along with it. And depending on the type you're only looking at 50-250psi. Voltages we can deal with, car coils kick out 100k-500k volts or more for ignition.
Yeah I seriously don't see this ever getting off the ground unless the container is designed to 'not' ever explode but in the even of a crash will only bleed pressure at a low level.
Om, nomnomnom...
http://en.wikipedia.org/wiki/Compressed_air_car
The compressed air car has been under development for a long time. It shows great promise but nobody yet has been able to make a practical vehicle.
The advantage of a hybrid vehicle is that it doesn't have to store enough energy for a complete trip. In particular, it stores energy (thereby heating the engine) and releases energy (thereby cooling the engine) over a short period of time. The pure compressed air vehicle has the problem that the engine is permanently in cooling mode. If the engine is hot, because it has just been compressing gas, it is far more efficient. The longer it operates as an engine, the less efficient it becomes.
The advantage of compressed gas for short time energy storage is that the storage is simple and does not take much sophisticated material as compared with batteries.
People raise the problem of a tank of gas stored at very high pressure. The hybrid vehicle doesn't need as big a tank. Also, they've been working on this for a long time. The problem is basically solved. It isn't nearly as much a problem as a tank of gasoline.
hmm short a super cap with some steel or aluminium bar, and let me know how it goes.... or simply ground one end to the car body and watch it light up a rescue worker/bystander when it ground through them.
All of the above was encrypted with a Quad ROT-13 method. Unauthorized decryption is in violation of the DMCA.
bugger the ethical treatment of gases.
i finally found a way to make popping candy!
when pressure cookers just aren't enough.
Your inflatable date will be ready for fun in no time!
There. Fixed it for you. (I like my women with hard bodies. But #2500? Sheesh!)
Have gnu, will travel.
Wait a minute... isn't that why people didn't want hydrogen cars in the first place?
No, it is because pure hydrogen has a lower energy density the hydrocarbons and it's highly difficult to store hydrogen (the tiny bastard uses the pores of the steel container to escape). See hydrogen storage.
What about supercapacitors?
Expensive like hell.
Those would be much safer than high-pressed nitrogen.
Would it, now? Just what you think happens when the hundreds of ampere*hours discharges through you body in the shortest time possible? Ah, you say: why through my body and not through the car's body? I ask you in return: why the nitrogen tank should explode instead of releasing all the gas through a "sacrificial valve"?
Just because it constitutes 78.08% by volume of Earth's atmosphere doesn't mean we should trap it inside high-pressure cylinders. What will PETG say?
Who? The polyethylene terephtalate glycol?
Questions raise, answers kill. Raise questions to stay alive.
What people sometimes forget about is that such a cycle can be theoretically 100% efficient: it's called the reversible adiabatic process -- completely reversible! As long as your gas storage system is well insulated and has low thermal masses, that is. You simply compress and heat up the gas and store it. Later on, you decompress and cool down.
Think of a gas sealed in a well-insulated, low thermal mass cylinder. You do some work to move the piston in, the gas heats up and compresses. You release the piston, the gas does the same work going out as it expands and cools down. If the system is perfectly isolated and there is no friction, you get exactly the work you put in.
This has the theoretical potential of being a rather nifty thing, but I don't know how the practical (engineering) side of things works out. It may be impractical, or may be not. Time will tell.
A successful API design takes a mixture of software design and pedagogy.
Your inflatable beach toys will be ready for fun in no time!
And the stout is so much smoother when using N2 instead of CO2.
Questions raise, answers kill. Raise questions to stay alive.
I hope there's a turbo button that vents the nitrogen to a rocket nozzle for when you want to pass someone.
Only if your van uses a 486 CPU. After that, it's just nothing or adjusting your BIOS setting (which requires a cold-reboot most of the time).
Questions raise, answers kill. Raise questions to stay alive.
KERS
For those who are not into car repair et al, Audi used hydraulic pressure accumulators for power brake assist. It's a great system, particularly for turbocharged cars, which spend a considerable amount of time in normal driving with low or no manifold vacuum (which is created by the pistons trying to draw air past a restriction, aka, the throttle vane. That big round thing your brake master cylinder comes out of? That's the vacuum servo. It uses surface area to multiply force from the vacuum.) Citroen used the same idea to power the extensive hydraulics used in their famous suspension systems. Mercedes did as well for their cars which had hydraulic power windows (!!), door-closers, and suspensions. Nowadays, the idea of hydraulic assist has largely gone by the wayside, with auxiliary electric vacuum pumps used where necessary. It's a shame, because the hydraulic system had a HUGE amount of reserve; you could pump the pedal hard almost thirty times.
The reservoirs are lovingly nicknamed "the bomb" by enthusiasts and owners of mid-80s-to-early-90's Audis, strictly on appearance; they look sort of like a large-ish cartoon bomb. I have NEVER heard of one exploding or failing (in terms of the pressure vessel, say, by cracking) in any way, and they've been in use for almost thirty years.
The way they DO fail, very predictably, is via the internal bladder that separates the nitrogen charge from the hydraulic fluid. Eventually the bladder fails, or the nitrogen simply diffuses through the bladder. Also, hydraulic systems are pretty horribly unreliable; with age, everything rubber fails eventually. Citroen did a pretty good job of proving that too, but on Audis, pretty much all the hydraulic hoses eventually fail. The hazard, in this case, is that when this system fails, it'll dump gallons of very slippery hydraulic fluid all over the road. If you're lucky, it won't also spray it all over, say, your hot exhaust. Atomized oil is pretty damn flammable.
Another danger: with the Audi system, all you had to do was pump the brake pedal until it was hard, and the system was safe to work on. This system would involve higher pressures and larger quantities of fluid...and it would become a real danger for anyone working on the car to do so with the system charged, as fluid over a certain pressure will either break skin or worse. I imagine they'll develop an easy way to discharge it, but people are still idiots.
The thing is also going to be a total bitch in a fire; I'm sure they'll put a pressure relief on the nitrogen side, but even then, you've got 10-15 gallons of flammable oil to deal with.
I really don't see Chrysler having any incentive to make the thing more durable than Audi/VW/Citroen did. It'll be made so it lasts about 60-70K, and then you'll be looking at replacing a huge, high-pressure tank. Expect the hilarity 3-4 years from whenever they go on sale, probably sooner.
Please help metamoderate.
The 1980s called and wants its air-powered toys back.
Yes.
I'm actually wondering about the opposite of most of the energy being released as heat. When you depressurize a small can of compressed air, it will freeze the can, as well as the object you are pointing it at. How much heat could a 14 gallon tank suck up if were to depressurize rapidly?
Ask a dive instructor who is old enough, and they'll tell you about The Time I Saw a Burst Disc Retention Cage Shoot Through The Side Of Someone's Trunk And Through The Car Next To It.
Also, burst disks are not 100% reliable, nor are the correct disks always installed.
So, don't use bursts disks, pick another (more reliable) version of a release valve (it's not like burst disks are the only way to do it).
Questions raise, answers kill. Raise questions to stay alive.
If the force applied to the tank in question is sufficient to cause a catastrophic rupture/explosion, then I would hazard to say that none of the parties directly involved in the collision are likely to care, as they're already dead.
Simply piercing the sides won't do it, you'd have to completely crush it. And considering the location and construction materials used, that's not going to be easy to do.
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As a scientist who lives off the grid on solar PV (for decades now), I've pretty much investigated every way there is to store energy, and it's not so simple a problem. Vanadium redox batteries (utterly impractical for autos and that membrane ain't cheap) look about the best so far in terms of simple and good while being efficient. Most things that do heat storage are only efficient if huge enough that the surface area to volume ratio can be really small.
The above approach might work out fine for small amounts of energy and for short times, however, and having some is better than nothing -- it probably is pretty reliable unlike most batteries which tend to have much shorter cycle life than is claimed. I think we're going to see a big backlash against battery cars at some point because of that one.
Why guess when you can know? Measure!
Tata is making subcompacts in India which use this exact method as a propulsion source to get around. However, what works over there might not work over here.
But, if the technology makes it over, just the fact that it can keep a vehicle running with the gasoline or diesel engine off at idle to low speeds in city traffic would save a good amount of fuel.
Any fire from the fuel will be put out instantly by the pressure releasing from the tank. It's like a really advanced fire extinguisher.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
UPS and the EPA announced something very similar two years ago.
http://articles.cnn.com/2008-10-28/tech/ups.hybrid.trucks_1_hybrid-trucks-hydraulic-hybrid-hydraulic-fluid?_s=PM:TECH
Did that really sound like I was asking a question?
Gasoline needs oxygen to burn. If the gas tank ruptures, and catches fire it still burns at a certain rate. If that tank ruptures it releases all the energy at once.
But they're not *that* bad, just lousy. More like you lose about 40% round trip, not 75% as you say, and that 40% is at end of life, when you get disgusted and buy new ones. Now that's at lower cyclic rates, eg capacity in 10 or more hours. The Li Ion ones are better for fast things, but still not great. But neither do you lose half each way....until they're about at end of life. The real sad story is that they're not going to have the claimed cycle life and a lot of buyers of cars where most of the cost was that battery are going to be real unhappy when they find out it doesn't live all that long and costs nearly the full car price to replace...even though like any car, the value of the basic car goes down quick the instant it comes out of the showroom.
The issue with a bunch of the other storage mechanisms is explosion risks. Gasoline burns, but only as fast as it can get air. Pressurized things (look at the safety history of early steam) let all the energy go in a fraction of a second....so, maybe OK in a system buried in a pit or something, but not so great in a crash. In a normal crash, you only release at most about 10 seconds worth of full engine power in the crash alone -- then maybe the fuel burns slowly. (reality isn't televised) Now consider what would happen if it was an hour's worth, all the car's potential energy released at once like a broken flywheel would do....not a pretty thought.
Which is another reason why things like liquid fuel will be around awhile, even though there are plenty of reasons to object to them. You don't have to carry the oxidizer, which with gasoline works out to about a 15::1 weight advantage...You burn about 16 times the weight of air (or at least that weight, which includes the nitrogen, goes through the system) for every weight of gasoline, which is what makes IC engines practical at all. With a battery, you have to carry both, in effect. With mechanical storage, you always have full total energy ready to go "bang" in an instant, not so safe.
We have a long way to go to get out of the woods on this problem, I've been studying it for a lifetime, and there's nothing new on the periodic table that's going to magically solve this anytime soon. LiIon already has nearly the energy density of high explosives....that's about the limit of chemistry, real or imaginable.
Why guess when you can know? Measure!
if crash=1 then dump-pressure
(Yep, I'm no programmer. But I don't think it'd take a rocket surgeon to tell the programmers how to make this work, given the myriad of accelerometers and such in modern vehicles.)
Kid-proof tablet..
(Yep, I'm no programmer. But I don't think it'd take a rocket surgeon to tell the programmers how to make this work, given the myriad of accelerometers and such in modern vehicles.)
Considering how many screw ups there have been over simple things like roll sensors, and ignition modules that are supposed to cut fuel in the event of a crash or roll over? Yeah...I don't know about that.
Om, nomnomnom...
This sounds reminiscent of the starting system used in the good old Yakovlev Yak-52 aircraft. They first started flying them in 1976 according to Wikipedia .... ah well, what is old is new again.
The typical chemical battery used in hybrids have very poor efficiency. It stores only 50% of the energy given and releases only half of the stored energy
Nope. Lithium-ion is around 90+ percent efficient round trip. See the note in the wiki article. Lead acid is around 70% round trip. Molten sodium is a very old technology that is actually quite safe, but has durability and power density problems.
Flywheels are great, but they're really scary. Flywheel hybrid research was mostly stopped when a wheel blew up and killed a technician at Chrysler. The problem with compressed air is that their is heating of the air during compression and cooling during expansion. If that heat does not stay in the air, there is efficiency loss.
What we need is really electricity priced the way cell phone minutes are sold. Peak hour, off peak and night rates. Then there will be an incentive for people to buy these things to store cheap electricity at night and use it in the day and reduce the grid load on hot summer days.
There already is for large industrial customers. The smart grid would bring that to homes. One of the consequences is negative electricity prices due to excess wind power. Even so, I did some bath that showed you could expect to make around 0.1 and 0.2 dollars per kWh of capacity per day. That's around 30-70 dollars a year per kWh. The cheapest batteries I know of are around 50-60 dollars per kWh and will be toast before they pay for themselves.
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Community is a cartel
the energy stored per kilogram is much lower than current lithium batteries.
For a non-plug-in hybrid, it doesn't really matter that much. What you're really after is a buffer to take up otherwise wasted energy and re-dispense it at the earliest available opportunity. The key isn't so much overall capacity - you just want something that can be charged and discharged fast enough and efficiently enough to satisfy the needs of normal city driving.
It's a good system that was implemented years ago by these guys:
http://www.permo-drive.com/tech/index.htm
From my quick perusal the systems look the same.
They even sold it to the US military for use in their FMTVs.
I, for one, will not drive at any speed in a tricycle vehicle with the single wheel in front. They are proven unstable in cornering.
Even bicycle-type tricycles: those that go at any significant speed have a single drive wheel in the back and two wheels up front.
I'm not saying that a "standard" tricycle will tip over at the drop of a hat, but they are less stable when cornering, especially when braking while cornering. The two-wheels-in-front configuration is provably more stable.
Doesn't a perfectly reversible adiabatic process also need to be quasi-static? I don't know the details of this specific case, but I don't expect the piston would always be moving very slowly.
I think it'd be OK. Most of the complaints you speak of are of safety systems operating when they shouldn't be, as in the case of the roll bar that deploys when there is no accident imminent.
If the tank ejaculates prematurely*, then all that is lost is a bit of fuel economy. After all, it doesn't cause a new safety hazard when this happens, as do roll sensors that fire pyrotechnic roll bars ($$$+possible injury), fuel pump cutoffs that require one to crawl into the trunk to reset it before proceeding, and the like.
All it means is that, after a hard turn (in a Chrysler minivan? FFS...), you get to complain to your friends about how your car quifes noisily when abused.
After that, the tank repressurizes by normal means, and everything's the fine.
It, therefore, can be tuned to be far more sensitive than the other systems that you mentioned, since nothing of any great value is lost (other than a bit of accumulated pressure).
Compared to existing systems, let's say it behaves as follows: if crash = .5 then [...]
*: I did want to come up with a better word usement, but it's growing late here and...well...I rather like the way that I wrote that.
Kid-proof tablet..
It sounded like you didn't have a clue.
http://www.scuderigroup.com/our-engines/
This engine is a split-cycle four stroke air hybrid that fires After Top Dead Center (ATDC) effeciently. The engine already holds far more pressure than standard combustion engines and reduces NOx by up to 80% and CO2 emissions by ~30% over similar hybrids and standard combustion engines - without the need of an ancillary system for power management (an electrical system for example). The engine presses out nearly 100% of the gas from the exhaust piston which leads to far much better optimization.
Don't carbon fiber flywheels in a vacuum chamber have a higher energy density? (and very high cost)
I read about special extremely long life (but lower energy density) nickle-iron batteries that last an extremely long time. And the electrolyte in them can be swapped after they do wear out to rejuvenate them.
Have you tried those? How well do they work for your off-grid system.
How do you live without A/C?
Yes, a regular hybrid "only" needs to store as much energy as needed to bring the car to a stop and accelerate it to highway speeds.
Which means that when the pressure vessel bursts, you have one car-at-highway-speed's worth of kinetic energy blowing up in your face.
Whatever happened to flywheels for energy storage? Popular Science couldn't shut up about them 40 years ago. Example: http://3.ly/Ccxs
If you thought a high-voltage hybrid was dangerous... ...then you're a moron.
Seriously, there's about fifteen billion "dangerous" things in an average car - adding a small battery and a few wires doesn't change that. The total energy stored in the battery of most hybrids is about the same as the energy in a few tablespoons of gasoline. And unlike the parts of the car that carry your fuel, the high-voltage parts are clearly indicated with bright orange coloring. The airbags are probably more dangerous than the electricity. And the voltage isn't even that high - usually a couple hundred volts at most - the same range that is in every home and office.
I have no doubt that engineers can make a high-pressure tank quite safe. In fact, they've already done it. The Civic GX (a CNG-fueled passenger car) holds natural gas at up to 3600 psi. As do many other CNG-fueled vehicles, though it's much more commonly seen on buses. Just replace the rather flammable gas with a rather non-flammable one, and you're there. Seems easy enough to me...
Adiabatic heating on compression would be pretty serious. A diesel engine only has 15:1 to 20:1 compression ratio, and develops enough heat thereby to ignite diesel fuel. In this system we are looking at upwards of 300:1. The temperature would be absolutely fierce.
If on the other hand you design the system to dissipate the adiabatic heat, you are rejecting a good proportion of the compression energy, which then you will not get back on expansion. So either you must withstand incredible heat in the system, or you sacrifice efficiency.
The mirror image is adiabatic cooling on expansion. If you do reject the adiabatic compression heat, then on expansion you will have problems with supercooling and moisture freezing.
On the other hand, any thermal leak is a very big energy loss. You're running a heater and throwing away heat on "charging", a cooler and then absorbing heat into the cooled gas on "discharging".
This is why compressed air is a rotten energy storage and transport medium. (In factories, however, it IS used as an energy transport medium because the inefficiency is offset by various design advantages in the devices it powers - typically linear actuators, large clutches on stamping presses, compact refrigeration and air cooling (using vortex/swirl tube refrigerators and vortex entrainment air pumps), and light but powerful hand tools.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
What we need is really electricity priced the way cell phone minutes are sold. Peak hour, off peak and night rates. Then there will be an incentive for people to buy these things to store cheap electricity at night and use it in the day and reduce the grid load on hot summer days.
They DO have these options: For industrial and commercial use. Residential just doesn't make sense for that.
#fuckbeta #iamslashdot #dicemustdie
Our tanks are filled to 4200psi.
http://en.wikipedia.org/wiki/Self-contained_breathing_apparatus
Quite correct, these same issues were raised when LPG tanks became populr here, but it is very rare for one to be ruptured, they have to be damn strong just to work, in most cases stronger than any object they are attached to or hit by.
Also: http://www.deir.qld.gov.au/workplace/publications/alerts/alloy_cylinders/index.htm And if you walk into any dive store, you'll find the filling station includes a large tub. That tub is reinforced and designed to take some of the force of a tank exploding.
Please help metamoderate.
Source please? Last I've heard, Nickel-based chemistries (early hybrids such as the Prius use(d?) Ni-MH) achieve 90% charging efficiency if fast-charged (that is, the battery stores 90% of the energy provided to it). And Li-ion's charge efficiency reaches an impressive 99.9%.
While compressed air may have many advantages over modern batteries, charging/discharging efficiency is unlikely to be one of them.
It's a good concept as an alternative to using generators to store the energy as electricity in batteries. The safety issue that people keep bringing up about the tanks exploding is pretty far fetched. When I was a mechanic Nitrogen pressure cylinders were used extensively back in the 70s on diesel engine equipped vehicles to create "hydro-boost", a device that did not require vacuum like a conventional power brake system. I never heard of any mechanics being hurt with these nor did I hear of one exploding. As a technology high pressure cylinders have been mastered. For example, I have used Oxygen tanks for oxyacetylene torch, brazing etc that were manufactured by the Third Reich in Germany. These tanks are still used and are recognized by the swastica near the top of the tank. The real hazard with tanks of this type is -- as someone else mentioned -- that the valve might be broken off, creating a rocket projectile of enormous power. No such hazard exists with the Chrysler project. Also the proposed compressed Nitrogen method of regenerative power saving is more reliable and does not require expensive replacement of all those batteries every 5 years, which is the real killer of all electric cars and is why they will never live up to expectation. Chrysler is on a good track with this and I commend them for their engineering and research and development.
"The word "unblowupable" is tossed around a lot these days..." - Homer Simpson
No it isn't. Class D power supplies are like 70-95% efficient.
I guess if you want a wave form other than square or sine wave it gets expensive - but what else would you really need in a car?
You can't legislate goodness. Let each to his own destiny, by will of his freely made choices.
But then with a flammable gas, used as a fuel. Those systems hardly ever fail, even in a crash. Yes, even on the German Autobahn, where there is no speed limit, they drive around with these cylinders in their cars.
I was promised a flying car. Where is my flying car?
As a scientist that has been studying how to store energy for decades you should know the difference between a method of storing energy that is theoretically 100% efficient, and one that it isn't. Most batteries are not theoretically 100% efficient. Adiabatic compression of an ideal gas is. How close you can get to 100% in reality is an engineering problem. With batteries there is a theoretical limitation that won't allow 100% efficiency.
What people sometimes forget about is that such a cycle can be theoretically 100% efficient
In theory, all cycles are 100% efficient.
If the system is perfectly isolated and there is no friction, you get exactly the work you put in.
Yes, if. Actual physical systems however are not perfect, and there will always be some thermal leaks, and some friction.
How do you live without A/C?
Aircon? Maybe he lives at the south pole. OTH solar powered aircon is just about the perfect solar power application. It doesn't need storage at all and the load scales perfectly with the supply.
I have been looking at PV cells for my house lately. Outlay after the subsidy from our state Government is such that the system would pay for itself in about five years. But if you factor in the opportunity cost of investing the money the payoff period is a lot longer.
http://michaelsmith.id.au
steel container, i don't think so, we're beyond that farce!
low energy, high power, this sort of thing is ideally suited to regenerative braking.
But at least the theoretical limit is full efficiency. With most hybrid-electric systems, the theoretical limit is under 100% simply due to resistance of various parts of the circuit and chemical behavior of the batteries.
There are some pretty darn good insulators out there. Think aerogel -- heck, that one even has scalable price vs. performance. You chose density that you can afford (lower: more expensive), trading off performance for better price.
A successful API design takes a mixture of software design and pedagogy.
DOT requires high pressure cylinders used in vehicles to be tested at intervals based on bottle type and service.
hmm short a super cap with some steel or aluminium bar, and let me know how it goes....
You will need to get a new fuse.
or simply ground one end to the car body and watch it light up a rescue worker/bystander when it ground through them.
The moment any HV cable touches the car body the GFCI disconnects power.
This is how it works in current hybrid cars.
We both said a lot of things that you are going to regret.
We have a producer in France (MDI), which build "CAT" engines and cars.
See http://www.mdi.lu/
-- Laurent Pointal
*On the Star Trek set...Scotty yelling into intercom...
Scotty: "I canna hold her together any longer! She's braking apart!"
Director: "CUT!" *sighs* James, baby, it's breaking apart, not braking apart.
Scotty: "?!?!? *mutters* Where's the Romulan Ale? This insanity needs a wee bit more than the 200 year old scotch, I think."
Down With Slashdot BETA!!! I've been around the corner and seen the oliphant; you can only abuse me from your perspecti
I was about to mention MDI. But there are two main differences:
- their cars are only concepts, and this for 10 years or more now. I live very close to their french factory, which has been operating, as far as I understand it, only from regional subsidies without selling a single car. They do have a demo model, which they show everywhere around, but definitely, I asked them many times how/where to buy: no way. So, I suspect there must be some flaw somewhere. Mind you, I was candidate to buy, and ready to pay. I understand what they say is, we only sell car factories themselves, not individual cars. I doubt this is the good strategy.
- their cars are air-powered only. This means you must get somehow a compressor at home, that will reload air in the car's tank at night. This is very different from Chrysler's hybrid concept, where a presumably smaller tank is filled by the (gasoline) motor either from gasoline energy or from braking. While I'm not sure Chrysler's device will be as efficient as its electric counterpart, it will work somehow for sure, and probably will lower the gasoline consumption in a measurable way. In comparison, from my experience with MDI, full air-powered vehicles just don't work. Apparently the end-to-end efficiency chain turns them into ultra-light, low-powered vehicles whose autonomy is just too low.
Herve S.
I don't know where you got you 50% number from, but i am pretty sure that on Prius hybrid cars the efficiency is quite high to reach a high fuel efficiency.
The whole problem with electric hybrid cars is the price. Here the pressured air solution can help. If the price of a hydraulic system is low, and it can be used to add power to the mix at the short moment maximum power (and maximum inefficienty) is required, it might be a good solution to get better fuel efficienty
What matters here is the total price of the car. If a small pressured air system adds a small price to the car, but the fuel efficienty is increased more than the added price this a good thing.
Maybe pressured air is less efficient than a electric hybrid, but still much more efficient relative to a non-hybrid car.
We might smell really bad after a wreck but we won't be burnt to a crisp.
* Winners compare their achievements to their goals, losers compare theirs to that of others.
> Chrysler's standard 2.4-liter four-cylinder, the base engine in its minivan line
---
You know, there may be another way to save some gas here..... (tip to Americans, in Europe and elsewhere, 2.4 liters is not a "base" engine)
> no, yes, maybe (tagging beta)
But at least the theoretical limit is full efficiency. With most hybrid-electric systems, the theoretical limit is under 100% simply due to resistance of various parts of the circuit and chemical behavior of the batteries.
There are some pretty darn good insulators out there. Think aerogel -- heck, that one even has scalable price vs. performance. You chose density that you can afford (lower: more expensive), trading off performance for better price.
If you demand aerogel for your insulator, I demand liquid helium cooled superconductors for my hybrid wiring and motor magnets.
If you demand theoretical 100% efficient compression (ha ha ha good luck), I demand the use of high-Q factor / low ESR supercapacitors in my hybrid design.
The problem with declaring a theoretical daydream of one design, superior to practical shipping product of a different design, is nothing stops the folks with the non-vaporware actual shipping product from also daydreaming...
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
Why not get rid of a lot of stop signs? Are stop signs that require a complete stop really safer than a yield? I see so many that seem unnecessary. Could low volume intersections be made smart so that stopping (or even slowing) is only required if there is oncoming traffic?
Honestly? why try grand experiments like this?
the 4 cyl engine already in these vans can gain a LOT of efficiency by simply adding in a transmission that is properly designed. a 7 speed transmission that adapts to the driving conditions, would boost fuel economy numbers drastically.
have a "city mode" that runs through the first 4 gears skipping 1st to take advantage of gearing at lower speeds, 1st is only used when the vehicle is loaded down with your 7 family members that all weigh over 250-350 pounds. the top 3 gears are used for highway cruise. Or let's use a CVT transmission to even further boost economy? (Note I know how notorious Dodge transmissions are for failing)
Couple that with a smart torque converter with lockup to eliminate losses after it is up to speed as well as decent aerodynamics and you can easily make a Dodge caravan get 40mpg on the highway and 20+ in the city. Will it accelerate to 60mph in 1.2 seconds and do the 1/4 mile in 9.2? nope, IF you need that buy something else. 95% of all minivans are used to carry the 3.275 kids and all their crap around town or drag the family across the state on a weekend trip to grandma's. They can boost the fuel economy numbers drastically with current technology. They just find that it get's more press and attention from the tree huggers if they can slap the word "hybrid" on the thing.
Why is detroit stuck on trying to entice car buyers into being beta testers?
Do not look at laser with remaining good eye.
Just ask people in europe how stable a 3 wheeled car (1 wheel in front setup) is...
the reliant robin is insanely stable and can take high speed turns easily.... F1 levels of stability!
http://www.flixxy.com/top-gear-car-review-reliant-robin.htm
Do not look at laser with remaining good eye.
>>I have been looking at PV cells for my house lately. Outlay after the subsidy from our state Government is such that the system would pay for itself in about five years. But if you factor in the opportunity cost of investing the money the payoff period is a lot longer.
Yep, I'm getting solar put in at my house next month. It'll break even after 2-3 years (50c/kWH is PG&E's high tier rates), though as you say you can generally do better with investments.
100,000 joules of heat will put you in intensive care for 3rd degree burns with a 10% chance of survival, and only requires having the bad luck of some other idiot plowing into my car at sufficient speed to rupture the gas tank.
Your magical bucket requires someone to be standing in front of a cannon.
Thanks for playing.
[End Of Line]
What's different from flywheels used in old (1920-30) Lanz and agricultural devices and the braking system in trains? Approx 8000 rpm should be achieved without danger.
Should be possible. Cars already have a "crash sensor" that triggers the airbags, self-tightening seatbelts, on some cars a fuel cut, etc. Just wire that up to a release valve on the tank. As soon as the car hits something the pressure could be vented.
"When information is power, privacy is freedom" - Jah-Wren Ryel
Oh noes scary hybrid with high-voltage wires! Not like regular cars that have no high-voltage ignition system at all!
And don't forget you have to call the hazmat team if a CFL bulb breaks!
Also ORGANIC FOOD IS PEOPLE!
"When information is power, privacy is freedom" - Jah-Wren Ryel
What people sometimes forget about is that such a cycle can be theoretically 100% efficient:
The Second Law of Thermodynamics begs to differ.
The truth is that all men having power ought to be mistrusted. James Madison
I seem to think that if this works, some of this tech could be retro fitted on older models and even other models altogether, and allow for some people to enjoy even more mileage to the gallon, no? I am no engineer, but could someone tell me if this can only work on those vehicles, or could be used on other older vehicles too.
I do agree that I was ahead of myself. Now for nitpicks:
Aerogel isn't a daydream. You can buy it. Costs reasonable amounts, even. If you wanted to insulate particularly hot CPU/GPU heatsinks in a laptop from the bottom of the case, a few mm of aerogel would be my choice, at a cost of maybe $10 or so. Maybe not in a $200 netbook, but Apple sure could pull that off if they needed to. Hot heatsinks are much easier to cool.
Superconductors are problematic due to rather theoretical reasons, too: good luck when you lose cooling (see what happened to LHC). Supercapacitors and low ESR don't mix. You get one or the other, and I think the reasons are to do with fundamental properties of the class of materials used in their design.
I don't really think that electric hybrids are very good at what they claim to do. Practical -- sure, but not very good at all. Unfortunately, neither are hydraulic hybrids, even 100% efficient ones, or really any other kind of hybrid, and I think that's where the buck stops.
A successful API design takes a mixture of software design and pedagogy.
No it doesn't.
One of my best friends is among the EPA engineers developing this technology. They've been working on it for years. He describes the difference between hydraulic accumulators and batteries with a water analogy like this: the batteries can hold a lot of water (energy), but you have to take it out with a straw. The accumulators hold less, but you get to extract it with a firehose. That's why the tech is so good for large, start-and-stop vehicles.
He also mentions that, when some fitting comes loose or a hose breaks, the invariable result is hydraulic fluid sprayed all over the floor or road.
The Second Law of Thermodynamics states that over time in a closed system the amount of energy available to do work reduces to zero.
The truth is that all men having power ought to be mistrusted. James Madison
This has the theoretical potential of being a rather nifty thing, but I don't know how the practical (engineering) side of things works out. It may be impractical, or may be not. Time will tell.
Its also, I believe, the same system that folk like UPS have been using for several years now on their Hybrid delivery trucks in the US. Very tried-and-true technology in general, the challenge is getting it out of the delivery/garbage market (heavy vehicles in which slightly overdesigned accessories (for reliability) are perfectly acceptable) and into the individual car/van market, where weight, NVH, and other considerations are more important.
You're special forces then? That's great! I just love your olympics!
This technology is nothing new. The EPA demonstrated several "Hydraulic Hybrid" delivery vehicles a few years ago. Wikipedia used to have a nice table comparing energy storage technologies (I can't find it anymore) and compressed air was one of the best IIRC.
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
Or bad-air-boom-crash?
Cornering tests have unequivocally demonstrated the relative instability of the "classic" tricycle configuration. Your example might be stable, but two wheels in front is more stable. There simply isn't any doubt about it.
Formula 1 has been using a kinetic energy recovery system for about a year now.
Porsche has introduced a variation of the 918 which features a similar system, sitting in the passenger seat. I'm not sure how I'd feel about having something spinning so quickly, sitting right beside me.
>>I have been looking at PV cells for my house lately. Outlay after the subsidy from our state Government is such that the system would pay for itself in about five years. But if you factor in the opportunity cost of investing the money the payoff period is a lot longer.
Yep, I'm getting solar put in at my house next month. It'll break even after 2-3 years (50c/kWH is PG&E's high tier rates), though as you say you can generally do better with investments.
You're (not) welcome.
The taxpayers.
Actually the head gasket/intake gasket/valve problems Chrysler was having was mostly limited to their Mitsubishi-sourced engines--the 3.0L V6 in particular. Chrysler's home-grown V6 engines based on the 3.3 did not have these same problems.
"Frequently wrong, never in doubt."
Lets say, in the event of an accident, can the tank of compressed nitrogen help with anything? ie: deploying the side curtain air bags? Or in the event of a fire in the engine bay, can it be used to attempt to displace the oxygen to quench the fire? I'm probably full of shit...
But it doesn't say precisely what that time is. It may be "long enough" as to be acceptable :)
A successful API design takes a mixture of software design and pedagogy.
It still means that no "machine" is theoretically 100% efficient.
The truth is that all men having power ought to be mistrusted. James Madison
Li-ion batteries in laptops and cell phones don't last long, but for automotive use they're using a different electrode (lithium manganese oxide instead of lithium cobalt oxide - see http://www.technologyreview.com/printer_friendly_article.aspx?id=26832) which they think will last a lot longer. I'd like to know when I can get the longer-lasting kind for my laptop. Or would they rather design in a short product life?
I want the MythBusters to get a hold of this one. I want to see how well the hydraulic fluid can cut off limbs when the hoses start to flap around under pressure.
Where this system wins out over the battery based system isn't in the efficiency of the electrical or pneumatic motor - it's the efficiency of being able to take in the braking energy quickly.
From memory (take that for what it's worth) a typical hybrid car can only convert ~40% of the inrush current you get when braking back into potential energy stored in the battery. A pump/tank system is about twice that efficient.
This is the same basic physics problem as why you can't recharge your laptop battery instantly, even though you really want to be able to get reloaded in the 10 minutes between flights you have left after you find a free socket in the gate area.
Correction, no one has used the Williams developed flywheel KERS system in F1. Every car to have run KERS to date has used a battery based system.
In any case, Porsche has demonstrated the flywheel based system and is going to use it in a production vehicle shortly.
Please stop underestimating the capability of engineers to DO THEIR JOBS......all the people on here talking about the safety need to go ahead and say out loud "i don't want to goto the 80th story of this building because, jeebus, I just don't know if they could make buildings that are that tall safe"...and then realize that your common sense is trumped by their engineering ability!
I KUT J00 M4NG!!!
If it's well-insulated, it would return to the temperature at which it started. It would just have to be very hot while compressed.
Stop! Dremel time!
Currently I am paying 18.6 c/KWH (Australian dollars but very close to unity with USD at the moment). If I had to pay your rates I would definitely be going for it.
The system I am looking at uses the grid for storage. You feed excess power into the grid and get part of the value of the power back. But you don't get all of the value back and you have to pay for extra hardware to interface with the mains properly so I am also looking at cooking up my own system which will supply a little bit more than the power requirements of the house during the day and not bother with storage.
http://michaelsmith.id.au
Yeah, systems with batteries are much more expensive, and you generally want to be on the grid, anyway, just in case you need more power one day. The connection gets installed for free by PG&E, but they also only credit you 8c/KWH for your power while charging you between 8c and 50c (depending on tier). But the way the math works out, you just push yourself down into the baseline tier, which is cheaper than solar anyway (which works out to 11c/KWH when levellized over 20 years, or 22c over 10).
Of course my ideas about auto safety include 5 point safety belts, real tubular roll cages, a fire extinguisher system that can be manually or thermally activated in the engine compartment and puncture proof fuel tank bladders.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
Yet.
I know tobacco is bad for you, so I smoke weed with crack.