MDI FlowAIRMDI FlowAIR will top the equivalent of 100 mpg, cost less than $18,000, and arrive in the United States next year.
Last summer, when gas prices revved past $4 per gallon and consumers starved for any alternative to petroleum, a glut of gas-free prototypes started making headlines. These weren't hybrids, or even all-electric cars. From water to wind and from the sun to the air, these one-hit wonders would allegedly ride on little more than the earth's elements. But they still had a few kinks to work out. This was, after all, the holy grail of the automotive world at the time: driving beyond gasoline.
But the automotive world has turned upside down — or maybe just down — in the months since. The major car manufacturers are desperate to stay afloat and build a battery-based hybrid that can save their proverbial bacon. In this economy, the research dollars for the next generation of alternative-fuel vehicles — hydrogen, diesel, even ethanol — have dried up faster than you can say "economic stimulus package." With more time to develop their miracle wheels, can non-Detroit startups save the car industry with pie-in-the-sky technology that doesn't depend on gas — or even necessarily cost a lot to buy? Or are these futuristic rides as overhyped as a solar-powered Prius?
Let's take a look at some 'elemental' cars, debunking the myths and rewarding the stars of so-called naturally powered vehicles.
AIR
MDI FlowAIRHow it works: Developed by ex-Formula One engineer Guy Nègre, this French minicar will top the equivalent of 100 mpg, cost less than $18,000, and arrive in the United States next year, says its American distributor. MDI's dual-energy engine uses pressurized air to power its motor by pushing the pistons round and round to turn the vehicle's crankshaft, just like a typical internal-combustion engine — only without the explosion of fuel. While this is good enough for slow speeds (up to 35 mph), it doesn't provide enough giddyup for highway driving. That's where the "dual" part comes in. Compressed air still runs the engine, but it is preheated externally just before entering the piston chamber. This hot external combustion of the adjuvant fuels, such as typical gasoline or even vegetable oil, provides expansion for the compressed gases and acts as a pressure multiplier, increasing the total applied pressure of the compressed air to the pistons.
