A Little Engine That Could Make Gasoline Obsolete

[bemildred]

Dang, Jiffy Lube is going to fight this tooth and nail ...

All are prototypes. Their bodies are made of aluminum tubing, fiberglass and injected foam. Prices are expected to range from less than $10,000 for the MiniCat to $16,000 for a six-seat sedan called the CitiCat.

These are no ordinary cars. Power comes from fresh air stored in reinforced carbon-fiber tanks beneath the chassis. Air is compressed to 4,500 pounds per square inch — about 150 times the pressure of the typical car tire. The air is fed into four cylinders where it expands, driving specially designed pistons. About 25 horsepower is generated.

Though technical problems are being worked out, company officials say the car is capable of 70 mph and a 120-mile range under normal city conditions, performance that is comparable to electric cars.

---

Recharging the onboard tanks takes about four hours using the car's small compressor, which can be plugged into any wall outlet. Gas stations equipped with special air pumps can replenish the tanks in about three minutes. Company officials say the oil only needs to be changed every 31,000 miles.

LA Times

[BigBearJohn]

1. This is such a GREAT story. THANKS for posting it.

I am emailing it to ALL my friends.

[m0nkeyneck]

2. small problem..

they rely on energy from fossil-fuel power-plants ;-(

[bemildred]

5. One will need electricity, or something.

But that is true of most anything with an engine. I would wager
in any case it's a good deal more "fuel efficient" than an 8-cylinder
SUV.

I have seen discussions of engines based on flywheels, and much
the same issues crop up, but this sounds more feasible.

[m0nkeyneck]

9. definitely..

better than a gas guzzling SUV.

now if they'd only start working on a method to keep me dry on me bicycle ;-P

[rustydad]

14. Pleeeeze folks....

The is no free lunch. This vehicle produces 25 horsepower. A SUV may produce up to 300+ horsepower. Apples and oranges. Compressed air is way too inefficient to use as a power source. Compressing any gas such as air produces a lot of heat, that's why large air compressors have cooling fins otherwise they would overheat and melt. Heat is energy and when produced in compressing air it is lost. I do not know how much energy is lost in compressing air but it is high. Also can you imagine what would happen when that car gets in a serious accident and the tank ruptures? Not good. A flywheel energy storage devise is far less wasteful of energy, that is in getting it spinning. But to be effective it has to be very heavy. Weight is the worst thing you want in an efficient vehicle.

The temporary solution to fuel efficiency is really rather simple. Unfortunately it doesn't make a lot of profit for TPTB. Here it is. It is a small aerodynamic vehicle that weighs in at less than 1000#. It will be powered by a small diesel engine probably in the 25 HP range. It will accelerate very slowly and likely cruise at 60 mph max. It will carry 4 in tight seating plus maybe 50# of baggage. Yet it will get over 100 mpg. It will cost less than $5000 and will likely be produced in China or India.

If we avoid a peak oil meltdown you may see these vehicle in a few years. They are already being produced overseas but are denied import into the US on the grounds that they do not meet crash tests. Well against a 6000# suburban or hummer or F-350 they lose for sure. Solution? Ban cars and trucks weighing over 2000#. Otherwise the discussion is pointless. Bob

[hunter]

19. Very lightweight vehicles are the only thing that can save the suburbs.

Suburbs will stop working as the cost of oil rises unless the roads and streets are reserved for lightweight and very efficient vehicles such as those you describe.

The streets of the future suburb will probably feature wide sidewalks and bicycle lanes. Motorized traffic will be almost 100% lightweight automobiles, motorcycles, scooters, and mopeds. Larger vehicles will be extremely limited, and require hard-to-get temporary permits and special licenses.

Otherwise the suburbs die. Imagine neighborhoods disintegrating because nobody can afford to drive to work. It will be "rust belt" America all over again.

[rustydad]

20. Yes, but...

How do we or can we pay the price of conversion? In California where I live the sprawl into the suburbs is intensifing. People often commute 100 miles each way to work. My fear is that there will not be enough energy both in the fossil fuel sense or in human energy to make the conversion. In which case chaos will rule. In my case I am doing quite well with a motorized mountain bike that weighs 35 #, goes 30mph+ and gets 250+mpg. Not too good on rainy days but summers are long in SC. Bob

[One_Life_To_Give]

21. Alternate Power Source

I think the only solution to prevent widespread famine. Is to develope a alternative power source. And manufacture hydrocarbon or other fuels using this source.

[rustydad]

22. Only two sources left

After fossil fuels there are only two sources of energy left to us. One is the sun in the form of wind, solar heat and electricity, wave power, hydro power, etc., all forms of solar energy. The second is nuclear. Either fission or fusion. Solar just cannot replace fossil fuels. It might work if we had planned for decades for a transition by becoming far, far more efficient in the use of energy. We delayed and the consequences are horrifying. Possibly some new use of nuclear may arise that has more safety and less cost....but so far that is a distant dream. Essentially we screwed ourselves and the future. Bob

[RafterMan]

3. Here's the home page

http://www.theaircar.com/index.html

They say it's only $2 to fill up the tank. Interesting.

[achtung_circus]

4. This is not energy

this is energy storage. The energy is still generated electricity, possibly from a coal-fired plant using "new technology" which is of course "good".

[bemildred]

6. It all comes from the Sun, and it's all energy storage.

The real issues are nonrenewables being used up,
and greenhouse heating due to carbon de-sequestration.
And of course, we are bollixing up the biological equilibrium
mechanisms that have kept the whole place comfortable for
life these last few billion years.

[achtung_circus]

12. Sure,

my very small point being that although efficiencies help, they don't address the real issues. Too many of these technologies, even the ones that work, are presented as new energy sources.

(not saying you had done so)

[bemildred]

13. No offense taken, or meant to you, Sir.

You are quite correct.

[gbwarming]

7. Hmmm... nine years later Guy Negre is still working out technical proble

This is a possibly cool idea, though the range and speed claims have always been suspect. Carbon fiber tanks are probably cheaper than high performance batteries but I believe the energy density is much lower. Around 2000 they (Guy Negre and his company MDI) were pushing these as taxis, and supposedly had licensing deals to build them in Mexico.

Like Paul Moller and his Aircars, this looks like one of those perpetual just-around-the corner technologies that always need just a little more investment. Here's an even older article I found on google groups:

http://groups-beta.google.com/group/sci.physics.fusion/browse_frm/thread/2f779a90deca2b60/acab3d24af6d93b4?q=Guy+N%C3%A8gre+1996&_done=%2Fgroups%3Fhl%3Den%26lr%3D%26c2coff%3D1%26q%3DGuy+N%C3%A8gre+1996%26qt_s%3DSearch+Groups%26&_doneTitle=Back+to+Search&&d#acab3d24af6d93b4

The Economist. Oct 26, 1996
Car engines - Not all hot air
...
But the most surprising aspect of Mr Negre's invention is that it
does not necessarily need petrol at all. He has found that
forcing a burst of cold compressed air into the combustion
chamber can deliver sufficient power to the piston to drive a
car. While engines running on compressed air are nothing new
the novelty in this case is that cold compressed air at 40
atmospheres of pressure is being added to that chamber when
it has already been charged up withair by the compression
stroke. Since compressing air also heats it the air in the
chamber is at about 400 degrees C and 21 atmospheres of
pressure. A hot gas expanding can provide a lot more useful
mechanical energy than the same quantityof cold gas at the
same pressure. Although less powerful than a petrol model
thezero-emission version of Mr Negre's engine can power a
car in city traffic for one hour on 15 litres of compressed air.
...
The first commercial prototype of Mr Negre's engine
unmemorably named the MDI-Ev3 is currently being tested by
ADMP a small engineering outfit that he hasset up for use in cars
and buses. With the backing of MDI an engine developer
inLuxembourg ADMP hopes to sell a licence for its technology
to a big engine-manufacturer. Public transport should provide a
convenient test-market for the engine and MDI has already
begun discussions with the Parisian transportauthority RATP as
well as with private bus firms to equip urban buses with the
compressed-air engine. A Parisian bus could run an entire day
on 1500 litres of compressed air which could be stored on
board. If Mr Negre's brainchild takes off Parisian smog may
one day be reduced to the fumes of Gaulo+ises.

============
The New York Times
November 24, 2000, Friday, Late Edition - Final
SECTION: Section F; Page 1; Column 1; Automobiles
LENGTH: 1461 words
HEADLINE: Pneumatic Car: Environmental Bonanza or a Lot of Hot Air?
BYLINE: By JIM MOTAVALLI

BODY:
WHEN considering the best power source for 21st-century vehicles, have the experts neglected the vast potential of the air around them? That is the assertion of Guy Negre, a French engineer whose previous experience was in designing high-performance Formula One racing engines for Renault and other teams.

Mr. Negre, who heads Motor Development International, a Luxembourg company also known as M.D.I., is doing more than talking about cars that would run on compressed air. He owns several patents on the technology and plans to start building two-cylinder "zero pollution" vehicles next year in Nice, France. Production is to be added later, he said, in Mexico, South Africa and the United States. But his plan has raised eyebrows among many researchers into alternative vehicles, who remain skeptical that compressed-air cars could offer a long-term solution to problems, like pollution and global warming, posed by internal-combustion engines.
...
Shiva Vencat, who heads M.D.I.'s operation in the United States through Zero Pollution Motors, an entity he solely owns, said the air car would be an "urban vehicle" sold mainly to fleet operators. At 55 m.p.h., he said, the range drops to less than 60 miles. The company is considering adding a small engine solely to heat the air, which, Mr. Vencat said, would potentially double the range.

[bemildred]

8. Aw, come on, spending venture capital is a lot of fun.

Why let the cat out of the bag?
:-)

[gbwarming]

10. Oh, sorry. Could I interest you in my methane hydrate mining venture?

just kidding. The compressed air could be useful for some applications - short range where numerous recharging opportunities occur. Refilling the tanks should be pretty quick (possibly limited by adiabatic heating of the air in the tanks) and much cheaper than battery systems.

[bemildred]

11. Indeed, how much would you like, in round numbers?

:-)

The methane hydrate stuff has been around since the 70s
that I remember. Big full color blurbs in Life or one of
those, I remember, with little white potato things on the
floor, and of course little gray potato things for manganese
nodules, and big vacuum cleaner thingys cleaning the sea-floor.
Never any explanation of how to get to it for less than a moon
trip costs in energy. But maybe global warming will take
care of that for us and vaporize it.

[rfkrfk]

15. This is a fraud

Would you buy a car, with a range of five miles?
Or perhaps, some car with a 200 HP engine, with
a half-gallon gas tank.
The issue here is... not power,,, but how
much time and power, ie how much energy is stored
in compressed air.
The 120 mile range, is a lie.

[Vogon_Glory]

16. Electricity Might Not Be Needed, Either

I can't help but wonder if solar energy couldn't be used in a more direct way to compress air to run these babies.

Some solar energy apps do a fine job of concentrating that heat and using that heat to run simple 2-cycle "pumps." Why not use that energy to run an air compressor directly instead of using it to run a generator to power an electric motor to compress the air to fill these compressed-air vehicles' air tanks?

[rman]

24. same old problem:

can we move from oil to solar energy quick enough?

[Dogmudgeon]

17. The Big Question

What is this method's EROEI -- Energy Returned On Energy Invested -- ?

This is probably a question for NNadir, who seems to know how to do those calculations.

--p!

[phantom power]

18. EROEI isn't really relevant to an engine design.

Engines always consume energy, to produce work. The EROEI measure is more about evaluiating energy *sources*.

For instance, does it require more energy to extract a barrel of oil out of the ground than you would get from burning that same barrel of oil?

That kind of question doesn't really apply to an engine.

[ChemEng]

23. What a joke....

Where does the energy come from for the compressor? Oh, electricity!

And where does that come from? The socket in the wall!

Never mind...

[rman]

25. Doesn't solve the problem:

There are plenty of renewable energy sources, and we do have the technology to collect and apply that energy. This "air-engine" is yet another example of alternative application of energy. That's not the problem.

What we don't have is the infrastructure to collect, and applications to use that energy.
We also don't have enough time to put that infrastructure and applications in place.
And we probably don't have enough energy left to make the transition in a mostly painless way.