100-MPG Air-Powered Car Headed To US Next Year

An anonymous reader sends us to Popular Mechanics for word on a New York automaker with plans to introduce a US version of the air-powered car, with which India's Tata Motors made a splash last year. Zero Pollution Motors plans a sub-$18,000, 6-passenger vehicle that can hit 96 mph and gets over 100 MPG, using an untried dual engine — the air-powered motor being supplemented by a second (unspecified) engine that would kick in above 35 MPH. The company estimates that "a vehicle with one tank of air and, say, 8 gallons of either conventional petrol, ethanol, or biofuel could hit between 800 and 1000 miles." The vehicle could be introduced to the market as early as 2009.

Comments

"Zero Pollution"?

[johndiii]

Probably no such thing. At the very least, there is waste heat from the mechanical processes of the automobile. The energy require to accelerate a vehicle to a certain speed will be roughly the same, regardless of the source. In the case of the "air-powered car", the energy used to compress the air could come from a coal-fired power plant. Is that better than burning gasoline? I don't know, and I would be very interested to see a comprehensive analysis.

In considering the environmental impact of a particular vehicle, there are a number of factors to consider:

• How the energy is obtained in the first place. From petroleum drilled out of the ground, a coal mine, natural gas, solar power, nuclear power, and so on.
• The efficiency of conveying the energy from the source to the user. Coal and petroleum products are relatively good for this (some loss to evaporation for gasoline, I imagine). For remotely-generated electricity, there would be transmission losses. If you charge your electric car from a solar panel on your roof, much less so.
• How the energy is stored (or storage losses). This is one of the big issues with hydrogen. It tends to seep through containers. Compressed air would be a similar problem. A leak in your compressed air tank has an environmental effect just as a lead in your gas tank, and is harder to detect. It's more efficent to store a liquid than a compressed gas.
• The efficiency of converting the stored energy into motion of the vehicle. What are the thermal losses for state changes? Friction in the engine?

There are probably more factors, some very difficult to isolate. And there are safety factors - gasoline is flammable, but easy to detect if it starts to leak. Hydrogen, on the other hand, you would not notice at all until your car decided to emulate the Hindenberg. :-)

Zero pollution is a good goal, but unless all of the factors are considered, it's just marketing hype.

Re:"Zero Pollution"?

[cupofjoe]

Another Hindenburg reference. Great fricking Caesar's Ghost.

Seriously, though - and on a tangent for a sec - he's got a point. No, not about a hydrogen-fueled car ACTUALLY bursting into flames a'la the great Lakehurst weenie roast (that's why he used a smiley-face, I guess) but - unwittingly - about the public's perception of the implications of having hydrogen on-board a road vehicle.

The truth is, technology wants to go in a safer direction. The US DOE is spending a lot of money - well-spent, in my opinion - on developing components of an automotive approach to hydrogen fuels, including infrastructure, end-to-end efficiency and cost, and of course materials science and engineering.

Check out http://hydrogen.energy.gov/

The long and the short of it is this: the current standard is to store compressed hydrogen on-board in 5000 psig tanks; the tech maturation for this approach is to up the ante to 10000 psig. Yikes; no wonder the public has the wrong idea - that's a lot of mechanical energy stored up in there. Some of the more interesting (but not new) technology DOE is funding is for "absorptive" storage, both liquid- and solid-state, wherein the hydrogen isn't at high levels of compression - rather, it's safely (for the most part) tucked away inside the molecular structure of a parent "carrier" substance. At fairly low pressures (~15-150 psig), for the most part.

Okay, tangent over. In the interest of full disclosure, I am a hydrogen materials engineer. And I'm WAY more frightened of gasoline vapors than I am of hydrogen in any form.

Cheers,
--joe.

Re:I'm skeptical

[zeet]

Turbochargers do increase efficiency. The only reason that turbocharged cars often do worse than non-turbocharged cars is the tuning. Small turbodiesels often get better fuel economy than similar output non-turbo diesels.