Looking For A Team For The Automotive Xprize

Are you suggesting doing away with the IC engine altogether? If so, what's your source of electricity for the compressor?

"Are you suggesting doing away with the IC engine altogether? If so, what's your source of electricity for the compressor?"

Yes, the IC engine cannot get enough energy out of a "gallon equivalent" to get the required mileage. The rules state that you use fuel supplied by the competition, gasoline, ethanol, diesel, biodiesel, electricity. I'd prefer to drive the compressor with a wind turbine, but that's not allowed.

instead of driving comparessor with electrical, why not use directly electric motor drive car?

so that it will become a electridynamic car. and has more efficiency than 90%

in a word: weight.

The best I can up with is a return to a steam engine. We now have the materials to do it over, better.

I can't imagine the possible weight savings (if any) ever coming close to making up for the lower efficiency inherent in compressing/expanding the air, and the efficiency loss due to multiple energy conversions: something to electric to air. (esbuck hasn't told us what something is yet).

But you can't get the efficiency to get 100 mpg, even with a humongous condenser.

It has to go 200 miles unrefueled, and I don't have a long enough extension cord. If I tried to carry batteries for 200 miles, the cost would exceed the max. allowed ($80,000).

Good to have you aboard. As another competitor, I can't join you, but I certainly wish you luck.

Also, in the spirit of wishing you luck, I hope you spend your time productively. You may already be aware of this, but compressing air is a very lossy process, and stored compressed air has very low energy density. Using existing technologies, a compressed air vehicle using US grid electricity as the prime mover would generate substantially more CO2 than a gasoline powered car per mile. If you have ways around these problems, that is extremely impressive -- and it would be great to see something fundamentally new. Direct solar hot air compression would be interesting.

There have been several threads here about the MDI air car, which would be worth reading, if you have not already. Also the DOE puts out a pamphlet (available on line) which quotes industrial air compression efficiency at somewhere around 15%, if I remember correctly (unlikely). In terms of well-to-wheels efficiency, using grid electricity as the energy source, the overall efficiency might be on the order of 3 or 4 percent, but you should check these figures. In industry, air power is used only if there is a compelling reason to do so (explosion hazard, need for cheap linear motion hardware, etc.) A standard gasoline engine car is about 15% efficient well-to-wheels.

But whatever you end up doing for the competition, you are in the right place: there are people here with loads of experience in many areas.

"Also the DOE puts out a pamphlet (available on line) which quotes industrial air compression efficiency at somewhere around 15%"

DOE is a bunch of narrow-minded bureaucrats. I submitted my idea to them, and they sent it to NIST. NIST said, yes, it would work, but they had something better. I asked where I could buy the something better, and they told me to get lost.

Compressing and expanding air is only lossy because of heat conduction. Consider the number of trucks which run around on air springs. If every bump dissipated 85 per cent of the energy...

I repeat, it was experimentally proven that a pneumatic transmission is more efficient than an electric drive, if you do it right.

Compressing and expanding air is only lossy because of heat conduction. Consider the number of trucks which run around on air springs. If every bump dissipated 85 per cent of the energy...

Of course, there are the losses due to flow through piping, valving, etc.

But in any case, I like the concept, and particularly your ideas from the other thread. Good luck.

Actually the IC engine is probably even less efficient than that. The car you describe is a variation on a plug-in electric vehicle which by using an electric motor to drive a compressor is even less efficient than a pure electric car and still has the limited range, long recharge time, expense and lack of convenience inherent in an EV.

On the plus side a plug-in EV uses cheap electricity from the grid and 80% of your driving is done within 25 miles of home. It can get the 100 mpg equivalent, but it is not a practical replacement for a fueled vehicle due to some negative points. Use of electricity for anything but driving reduces the range, so A/C, electric heat, power steering, brakes and accessories are a problem. More range [300 miles] requires more batteries and more expensive ones, pricing the long-range EV out of the mass market. On the road they require a 220 V outlet and 6 hrs to recharge, making them very inconvenient for long trips and even with shorter recharge times, the short range EVs are very inconvenient if it is needed to go more than 50 miles. They are touted as zero in pollution, but actually the pollution is just moved to the electric generating plants, of which there must be twice as many as we have now.

Actually a small steam engine powering a generator to keep the batteries charged and using electric motors in the wheels is a more efficient method. Adding thermoelectric power using waste heat and regenerative braking would increase the efficiency. The steam engine would run at its most efficient speed to turn the generator at its most efficient speed. It would only run when the batteries charge was low to recharge them. A water tube boiler [no, they do not explode] using ribbed stainless steel tubing could be made more compact than those of the old steam cars. Using a forced draft burner makes the emissions lower than for an IC engine. The fuel could be any liquid or gas, but one which produces the most heat per pound at least cost would be most efficient.

Since the first 50 miles uses no fuel, just electricity, and since 80% of driving is less than 25 miles [50 mile round trip], fuel would be used only for the 20% of driving over 50 miles or if cold or hot weather used more electric heat or A/C. This should, over a year of driving, be much better than 100 mpg, even counting the electricity from the grid.

If the prize is given for a car that can go 100 miles on 1 gal of fuel, a steam electric hybrid could win since it would use no fuel for the first 50 miles. Since the efficiency is greater it could also go farther per gallon on a 500 mile course. Seems to be worth a try at least.

I saw this discussed by beesidemeusa@yahoo.co.uk under the steam-electric reference in his e-mail.

I'll try to keep this as short as possible.

First off, the absolute minimum of work that must be done in that 100 miles is the drag force X displacement. At significant velocity this will be a function of the aerodynamic cross-section and coefficient of drag. Plainly stated, to get that 100 miles per gallon, the body of your vehicle is going to be very aerodynamically slick. Don't neglect the under body.

Second, regardless of your prime mover type, it will probably operate more efficiently if you can average the power output over the entire cycle. This will require an auxiliary storage device which doubles as your regenerated brake energy storage device. A storage device capable of storing an energy equivalent 4 accelerations from stop to sustained operating velocity would give you the capability of averaging power loading of the prime mover as well as allowing for very high accelerative performance through the entire range of operating velocities. Where grading is not going to be an issue, the storage device could be reduced to a capacity equal to a value slightly above one acceleration. The ability to "average" loading of the prime mover should allow you to reduce max output requirements to about 1/3 of a non-averaged process. This translates to a very significant reduction of the mass and volume fraction required for the prime mover and more than offsets for the small storage device needed for the process. The key component is going to be the Loading Control Program used to control prime mover output. This LCP is going to be THE fundamental breakthrough in Hybrid technology and it is conceptualized as being beautiful in its simplicity.

I haven't looked at the competition capability requirements for a long time, but if substantial grading or stop and go cycles are required, regenerative capability is a must.

My favorite configuration is a micro-turbine generator feeding a capacitor storage device. Why? Because of the high power densities and life cycles of capacitors. I haven't done the math for many years but since the total energy to be stored is relatively quite small, the mass and volume fraction dedicated to the storage device may be smaller than imagined. I know the energy density of capacitors is very low, but modern dielectrics have both quite high dielectric values and strengths. The most problematic challenge in this configuration is the power and voltage control. These control systems are conceptualized as being quite novel to allow precise power control to the drive motors with very low resistive losses and with all power being taken through put the storage device thus totally isolating prime mover control from operator input.

I capacitive storage is out of the question then ANY storage medium capable of high power densities will work.

The power will be applied to 4 regenerative capable integral wheel hub motors allowing for independent tractive control in both power and braking modes. No drive train, no transmission.

I am sure the engineers out there in CR4 land are ready to challenge this configuration, and I have spent the last 30 years preparing the answers.

I'd love nothing more than to discuss this in an open forum for everybody to take there best shots and making it work or disassembling the concept.

Gavilan

http://www.bestsyndication.com/Articles/2006/c/carter_mark/031206_hybrid_cars.htm

Be patient with the load up.

Capacitors are a splendid choice for energy storage, but they are beyond my capability.

I do not need superslick aerodyanamics, carbon fiber structure, or anything else exotic. The energy equivalent of a gallon of gas (30-40 kW-hr) is adequate to push an ordinary car 100 miles, if you don't waste most of it warming up the atmosphere with radiator and exhaust pipe. Further, the car has to be done in a year, complete with nice interior, an audio system, air bags, etc. It makes sense to start with a vehicle which has all those. Read the f---ing race rules, dreamed up by a committee of mostly non-engineers.

By the way, with compressed air, heating and cooling are easy. The air is hot, for heating, and expanding it cools it, for cooling. The heat and A/C don't have to be on during the race.

The air compressor is not in the car. (It could be, for a hybrid, but the rules...) Air is the "fuel", preferably made by a wind turbine or other "green" power source. (Steam would be fine, made with recycled romance novels) However, the rules require fuel supplied by the race committee, and electricity is the best option available. At the pit stop, there is a large compressed air tank, already full, and the recharge of the car can be done in a minute or so with a hose, much faster than you can recharge batteries and much faster than you can recharge capacitors, given the amperage limitations of the electricity source.

Regenerative braking is inherent, if you have the right valve train; put the air motor in reverse, so to speak. It shouldn''t be necessary.

If the compressor is at home, you have all night to top off the tank. If it's at the school, and you are using zero-emission school busses, you can store a few days worth of air and fill at your liesure, with a wind turbine atop the football stadium drivng the compressor directly, with no electricity required. Similarly, if you are on an island, a remote research station, or an off-the-grid third world thatched village, wind turbine produced air can supply an electric generator, a clinic's refrigerator, a vehicle, a farm tractor, etc., and, by the way, the exhaust has distilled water in it, which is much nicer to drink than the river water.

"If the prize is given for a car that can go 100 miles on 1 gal of fuel, a steam electric hybrid could win since it would use no fuel for the first 50 miles. Since the efficiency is greater it could also go farther per gallon on a 500 mile course. Seems to be worth a try at least."

First, they would charge you for the electricity, its gasoline equivalent. Second, the steam driven electric generator would not have "greater" efficiency. Assuming the exhaust emperature is close to 373 K and the steam temperature is less than 600 K, the efficiency will be low. You might get about 30 per cent, if you could exhaust into a vacuum, but you can't on a vehicle. At 15 per cent efficiency, you have no advantage over an IC engine, except that you may be able to use cheaper or "carbon-neutral" fuel. Sorry, that won't win the xprize.

Knowing how politicians think, they probably won't let you drive a steam car without a steam engineers' license. That used to be the case in New York. Then the Feds will demand an annual boiler test, about $30,000. The insurance rates will be high, not because steam is necessarily dangerous but because it is percieved to be dangerous. Fortunately, they haven't yet thought of issuing air licenses.

I see no reason to complicate the design by designing a hybrid.

This will increase cost unnecessarily, since steam power in inherently multi-fuel.

When it comes to steam: if it burns, it turns.

The attraction to steam is that much more of the energy can be used by recirculating combustion exhaust and condensate heat. In a perfect system, the exit temperature of the water would be equal to ambient.

<<The attraction to steam is that much more of the energy can be used by recirculating combustion exhaust and condensate heat. In a perfect system, the exit temperature of the water would be equal to ambient.>>

Please explain what such a perfect system would look like. Has one ever been built? It seems the exit temperature of a steam engine must be the the temperature corresponding to the exhaust pressure (1 bar without a condenser, hence 373 K). Even with a condenser, you are still wasting the heat of vaporization by cooling the condenser. Do you know something about steam engines that the US Navy and major electric utilities don't?

I just don't have the time to patent every idea that pops into my head.

Anyway, my idea has already been confirmed:

http://www.freepatentsonline.com/4104869.html

This steam engine uses an external combustion chamber where fuel is burned in the presence of air, both under pressure. Steam is forced into the combustion chamber at a medium pressure, thereafter being heated by combustion. Steam from the combustion chamber is released to do work in the engine, the pressure falling. Exhaust steam heat is recovered in a heat exchanger by condensed water which is turned back to steam. This new steam is compressed, after which the steam is injected into the combustion chamber to be heated.

In other words, the boiler feed is preheated.

In a perfect system, you would use peltier junctions, alcohol evaporators, etc. to extract all the energy from the steam exhaust, then put it all back in form the combustion.

Or you bias the system nearer to working energy levels, but then you have to insulate.

The basic imperative is to waste no heat.

Which goes back to my continuing confusion on your premise.

Are you saying that

fuel>>electric utility>>compressor>>kinetic

conversion process is better than

gas>>heat>kinetic?

only if the fuel is nuclear (or nucular for some) and that has really hidden costs.

I disagree, since the latter process has no hidden intermediates and by insulating/preheating, etc., less heat is wasted.

The former has the true chain:

gas>>heat>>kinetic>>electromagnetic>>transmission>>conversion>>magnetic>>kinetic>>compression>>kinetic

The 2nd thermo law predicts the latter will have a better chance of success.

The main issue is the rules and exactly how they are written and enforced.

Perhaps I can pester you less with my stunning stupidity if you provide a citation from the rules document to direct my reading more precisely.

"Are you saying that

fuel>>electric utility>>compressor>>kinetic

conversion process is better than

gas>>heat>kinetic?"

Yes, you have to read the rules.

In a perfect system, you would use peltier junctions, alcohol evaporators, etc. to extract all the energy from the steam exhaust . . .

I'm not sure about alcohol evaporators, but you can forget about Peltier junctions. They are expensive and their conversion efficiency is on the order of a few percent. There's no way they'd ever be economic - unless you have an invention there too :-)

Steam engines are more efficient than IC engines by quite a good margin. Add regenerative braking and thermoelectric generation of power using waste heat and the efficiency goes up. If IC was more efficient then all our electricity would be made using IC engines, but most of our electric power is generated by steam engines. You need to do some research on steam before you assume that they are not better.

Stupid, ignorant, short-sighted politicians and insurance [financial] people always stand in the way of progress. They want us to use cheaper and "carbon-neutral" renewable fuels, then block the way with stupidity. Follow the money, the taxes, the political power and you will see some of the reasons for it other than stupidity.Let a tank or two of compressed air or gas explode and they will limit that too, even if the tanks were not in vehicles. No Stanley or Doble boiler ever exploded, but the stationary ones in buildings did, therefore ALL boilers were deemed dangerous. Idiots!

The cost of the initial electrical charge would be equivalent to only a small amount of gasoline. The actual fuel would not be gasoline, but a bio-fuel, such as vegetable oil which should count as a plus if the rules were fair.

"Stupid, ignorant, short-sighted politicians and insurance [financial] people always stand in the way of progress."

And of course, when considering mobile power production, let us not forget the mass and volume fractions of the prime mover, power train, fuel, and subsystems.

I have been a student of transportation technology my whole life and there is nothing I will love more than to see the power process of the automobile evolve beyond mass/volume intensive real time demand on the prime mover and the dumping of the vehicle kinetic energy through friction braking.

I am finally seeing the American Automobile industry tumble to the inherent efficiencies of hybrid technology. This, along with other geo/economic developments gives me some hope that the US can regain its technological leadership in the auto industry, and in doing so have a profound effect on the direction of world transportation technologies; providing the US as a whole can get a handle on debt and medical costs that so negatively impact the competitiveness of the industry and overall economy in the world market.

You folks are the leaders in those technologies. Don't think for a moment that your efforts go unnoticed by other folks within industry, who, because of the nature of organizational power, behave much like the bench sitters in Plato's "Allegory of the Cave." Your efforts draw their focus away from the shadows and into the light. Once they become accustomed to that light their nature will draw them to the new technologies which you are promoting. They will seize them as their own and leave you with only the memory. If you folks want to really make a difference. Get inside where there is the resource to really make things happen.

In the end the market will declare the "winner" in this technological competition. The "winner" will be the organization that can design, market, and sustain the production of safe, practical, and fuel efficient vehicles. This involves much more than just the physical parameters of vehicle design. It will involve leadership with the technological acumen and insight to comprehend both the technology and its future effect on the industry.

Because of the capitalization required to bring to fruition a new player in the mass production of an automobile, I don't see new companies as being the big players in this technology; at least not in the US. Again, if you really want to impact the industry, get inside.

A long time ago, someone once said " It is amazing what one man can accomplish if he is willing to give other men the credit." In the evolution of capitalist economy this has become; "It is amazing what one man can accomplish if he is willing to give the company the profit."

When you guys get done reinventing the automobile how about looking into flying from NY to LA in 90 minutes without getting more than 2 inches off the guide-way? Airplanes are too dangerous, too slow, and too inefficient.

Gavilan

So, are you looking for a team or just want questions answered?

"So, are you looking for a team or just want questions answered?"

I want a team. I need a sponsor or two or three. Ideally, there would be a sponsor who has the facilities and skills to do the vehicle conversion, a sponsor who can sell 10,000 of the converted vehicles (the race rules require a business plan for mass production), perhaps a car manufacturer or major distributor, and a sponsor who has an interest in selling air compressors or pressure tanks and who will provide the compressor and tanks. Oh, yes, there's a $5,000 entry fee I don't have.

There aren't a lot of questions to be answered, except by trial and error. An IC piston engine can be converted to air by changing the valves. Conceptually it's easy, but mechanically... The race rules require real-time radio transmission of the instantaneous mileage (for the TV viewers), and I haven't figured out how to do that yet. I assume one skilled in the art can do it. The biggest problem in the conversion is fitting in enough air tanks, both volume and weight, for a 200 mile range. (I estimate 80-100 cubic feet to be safe) I could convert my Prius, if all I needed was fifty miles, but for 200 miles I suspect a minivan or pick-up truck would be better. If it were a purpose-built vehicle, starting from scratch, it would have an immensely strong platform chassis, about a foot thick, made of air tanks. Someone more proficient than I with computers should write a program to optimize temperature, pressure, volume, weight. Otherwise we do what the Germans did, just do it and learn form our mistakes, if any, in the good old American hot rod tradition.

I think I get it now.

Our friend has found a loophole in the rules.

If the contest sponsors are going to calculate the equivalent energy of the medium (compressed air) and EXCLUDE the means (lossy compressors), he will win. A hollow victory for everyone except him and his bankers.

He loses almost no heat!

IC loses a lot of heat.

If I am wrong about how the energy equivalents are tracked (it is late), then there will be a big problem.

So, please clarify this point.

Steam would not have the exit temperature you think though; we are quite a bit more clever handling the stuff than we were 'back in the day'.

Your bureaucratic analysis may be spot on though. But hey, it can't be worse than billions of little Hindenbergs rolling around the planet!

"If the contest sponsors are going to calculate the equivalent energy of the medium (compressed air) and EXCLUDE the means (lossy compressors), he will win. A hollow victory for everyone except him and his bankers."

No, they will charge for the electricity to compress the air, just as they would charge for the electricity to charge batteries. However, the lossy compressor isn't that lossy. As noted, experiments have shown the compressor/air motor can be less lossy than electric generator/electric motor. Compressors are only inefficient when they dump heat itno the environment. If the heat energy is conserved, friction losses are not particularly bad.

Using the formula for kinetic energy, calculate the energy of your vehicle at cruising speed, now using the formula for aerodynamic drag force for the required cruising speed , multiplying it my a displacement of 10 kilometers; adding the kinetic potential and (drag force X displacement) should give you a very rough but conservative figure of the approximate energy required to accelerate and cruise your vehicle at constant speed for 10 kilometers.

What is the volume and pressure of an air tank required to store an equivalent energy? What is the formula for calculating that energy anyway?

How about a hydraulic accumulator? How is that calculated? I would think it would be somewhat similar to a air tank.

Anyway, what does air power look like now?

Gavilan

From another thread on CR4 relative to this topic.

Hari gave:

1. The CAR Equation:

We did talk about the Car equation earlier:

F = mgC_rr + ½ρC_DAv² + ma + mgsin(θ)

Explanation:

F = force required at the wheels of the vehicle
m = mass of the vehicle
C_rr = coefficient of rolling resistance between tires and road surface
ρ = density of the ambient air
C_D = coefficient of drag of the vehicle in the direction of travel
A = cross-sectional area of the vehicle
v = speed in the direction of travel
a = acceleration of the vehicle
g = local acceleration of gravity
θ = angle (relative to horizontal) of the road surface

I added:

First component = road drag force.

Second component = aerodynamic drag force. Please note the square relationship between velocity and drag force.

Third component = vehicle kinetic accelerating force.

Fourth component = grade force.

So now take your instantaneous sum force and multiply it times the velocity. You now have the instantaneous power requirements.

The 55 mph sustained velocity on 7.5 percent grade is probably going to be the limiting requirement of the AXP. I could do this with a hybrid system through a limited change in gravitational potential and meet the other parameters, but not if my prime mover must produce continuous sustained power at that rate. The change in gravitational potential (the total height of the grade) needs a reasonable limit before I could go any further.

I think I have now roughed out the power and regeneration circuit.

Gavilan