About four years ago I became aware of research being done in France on the possibility of cars that run on compressed air. What a simple, elegant solution. Commuter cars do not travel that many miles, and could easily make the commute between refills of air. While an energy input is needed to recharge the air cylinder, it is easier to clean the stacks of an electric power plant than to clean the exhaust of the tens-of-thousands of cars that clog the cities during commuter rush hours. Will it work? I do not know, but the idea should be getting research money.

Here is a link to a site promoting the compressed air auto. Below is a skeptical article from 2000 from the New York Times.

Full Text :COPYRIGHT 2000 The New York Times Company


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.

Mr. Negre's proposed line of pneumatic vehicles would consist of a minivan that could serve as a taxicab, a pickup truck and a delivery van. The company estimates the cars' retail prices at $13,000 to $15,000.

M.D.I. says its five-seat, plastic-body car can reach 30 miles an hour in 7 seconds, cruise at a top speed of 60 m.p.h., and travel 120 miles on compressed air alone before needing a recharge from a home air compressor (four hours) or a service-station unit (three minutes).

The air would be stored in carbon-fiber or fiberglass tanks at very high pressure (4,351 pounds per square inch), then combined with warmer outside air in the cylinder to move a piston. Mr. Negre has said that his car would actually scrub the ambient air with on-board carbon filters.

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.

Compressed-air vehicles are not a new idea. Steam engines work on a similar principle. Around 1900, compressed-air trams plied the streets of Paris, and in his recently discovered 1863 novel, ''Paris in the 20th Century,'' Jules Verne imagined compressed air as the wave of the future on the rails. But the trams made only short trips, and attempts to run cars or trucks on compressed air have foundered on the weight of the air tanks needed to obtain a minimally acceptable range of 100 miles or more.

The range problem also bedevils battery-powered electric cars. Glenn Bower, a professor of mechanical engineering at the University of Wisconsin, who with his students has designed hybrid-power vehicles, said he thought that compressed air compared unfavorably with batteries as a medium for storing energy. ''Compressed air is probably 5 to 10 times less efficient than a battery electric system,'' Professor Bower said.

Prof. Andrew Frank, who designs hybrid cars and trucks at the Future Automotive Technology and Engineering Center of the University of California at Davis, said that air compressors were inherently inefficient, losing at least half their generated energy as waste heat. ''It's a losing game because the efficiency is just not there,'' he said.

And Dave Hermance, executive engineer at the Toyota Technical Center in Gardena, Calif., said that a commercially acceptable, safety-certified vehicle running on compressed air alone would probably have a range of only 10 miles. Accepting the new claims for the energy potential of compressed air would require ''a complete rethink of everything that ever was,'' he said.

Nor are environmental groups rushing to embrace the concept. Dan Becker, director of energy programs at the Sierra Club, said that attention paid to pneumatic vehicles was a distraction from the serious work under way on fuel-cell and hybrid cars. ''It seems silly to come up with some entirely new device that clearly has limited range,'' he said, adding that such a car would be only as clean as the plants that produced the electricity used to compress the air.

Mr. Vencat countered that compressed-air recharging stations could be built along rivers, making use of environmentally clean hydro power, and that the cars could theoretically have roof-mounted solar panels to create the electricity they would need to run the air compressors on board.

Even some of those who have experimented with new uses for compressed air are skeptical of the company's claims. Per Arne Rikvold, a physics professor at Florida State University, has built two generations of two-cylinder compressed-air cars -- but they are tiny models made of Lego blocks. ''What I do is for fun and to teach engine principles to students,'' he said. ''If you scaled up my designs, you'd probably expend so much energy compressing the air that it would not be worth your while.''

Tom Hanson, a retired aerospace engineer in Santa Clarita, Calif., has not actually built a compressed-air car, but he is working on one. Mr. Hanson has drawn up specifications for what he calls the Airlectric car. His design uses a lightweight 175-horsepower air motor and carries 60 percent of its energy in four 3,000-p.s.i. air tanks and 40 percent as heat stored on board in a thermal storage unit -- akin to a giant thermos bottle. Installed in a lightweight, aerodynamic body and chassis, this combination could attain a 60-mile range, Mr. Hanson suggested. An 8-horsepower engine running on compressed natural gas could theoretically extend the range of the Airlectric to 300 miles.

Mr. Hanson developed his concept in 1998, and says he hasn't been able to generate any interest from the auto companies or regulatory agencies. His one prototype is only half built. ''If they are using just the air from the on-board tanks, they'd be doing well to get 20 miles of range, even in a small commuter car,'' he said. ''Maybe they have some ideas I haven't thought of.''

The federal government looked at compressed air as an energy source as part of its Partnership for a New Generation of Vehicles; that program, which includes the domestic automakers, aims to develop 80 m.p.g. production cars by 2004. Dan Reicher, assistant secretary for energy efficiency at the Department of Energy, said the tests went nowhere. ''We are not spending government dollars on compressed-air systems for vehicles,'' he said. ''Through the Partnership for a New Generation of Vehicles, we made a major decision that future propulsion systems in automobiles will be built instead on hybrids and fuel cells.''

Despite the skepticism, Mr. Negre and his partners seem confident as they sign up investors by offering shares in regional manufacturing operations (for a minimum of $10,000). Mr. Vencat said the company had no immediate plans for a public offering in the United States, but would solicit individual investors once it filed documents with the Securities and Exchange Commission.

Mr. Vencat said the company had raised $5 million in investor capital, mostly in France, but would need about $160 million to build the 20 plants it is planning. Still, Mr. Negre said in a telephone interview on Wednesday that sales would begin in France in the second half of 2001 and in the United States ''not before 2002.''

Mr. Vencat said the company was considering a factory site in Kingston, N.Y., and had discussed potential tax breaks and incentives with the Ulster County Development Corporation. He added that Newburgh, N.Y., was also hoping to attract the plant.

The company's marketing effort has been helped considerably by favorable and often credulous media reporting about ''the car that runs on air.'' A July 10 segment on ABC's ''World News Tonight'' referred to the vehicle's ''combustion chamber,'' even though nothing is actually burned in a compressed-air car. A BBC report said that if the car ''lives up to all the hype, it could offer a serious challenge to the current motor vehicle market.'' A photo caption in The Times of London said the M.D.I. taxi ''blows away the competition.''

Several news media accounts alluded to an order of 40,000 pneumatic taxis for Mexico City. M.D.I. has a Mexican manufacturing partner, but the 40,000 figure represents only a potential sale based on the size of the city's taxi fleet, Mr. Vencat said.

Mr. Vencat acknowledged that some of the information the company had posted on various Web sites was confusing and that some of it implied that M.D.I.'s engine combined internal-combustion technology with an air motor. He said this early dual-purpose engine had been abandoned in favor of a simpler, compressed-air-only design.


Source Citation: Motavalli, Jim. "Pneumatic car: environmental bonanza or a lot of hot air?(compressed-air cars)." The New York Times (Nov 24, 2000 s0 pF1(L) col 1 (32 col): F1(L). InfoTrac Newspapers. Thomson Gale. McLennan Community College. 15 Aug. 2006
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