Angelo Di Pietro is an Italian engine designer who once worked for Mercedes Benz on their Wankel Rotary engine in 1969-1970, then migrated to Australia to pursue other interests, among them, as hobbyist / inventor of the Di Pietro Rotary Air Engine.
Rotary air motors aren't new, as any mechanic wielding pneumatic tools can tell you. The father of a high school friend of mine ran high pressure pneumatic hoses from their basement to several ports around his garage / workshop, so that he could conveniently plug in his tools without dragging a compressor around behind him. What's unique about Di Pietro's Rotary Air Engine is its ability to turn with a pressure differential of a mere 1 psi. This is accomplished by the use of sliding air gates or dams at six points around the rotor, which limit air flow, forcing the high pressure air to push the rotor, instead of rushing by it.
This very efficient, effective, non-reciprocating configuration allows the air engine to be very small and compact, yet very powerful. Any car guy worth his salt should recognize that this combination of high power and small size / weight translates into a great application for personal transportation. To that end, Di Pietro has adapted his air motor to carriers for produce markets, ATV load carriers, scooters and even boats (shown).
This rotary air engine would also work well as a range extender for fleet vehicles with local routes. A rotary air engine is a great match for a generator, as they both spin and work best at constant speeds. A fleet conversion company like AutoPort, Inc. could replace the internal combustion engine and fuel tank in a Chevy Volt with an appropriately sized Di Pietro Rotary Air Engine and a couple 700 bar air tanks from Quantum Technologies, and deliver a zero emissions vehicle that can be rapidly refilled at the company site.
While not as efficient as a large battery or fuel cell system, it is certainly far cheaper upfront, while still offering rapid refill capability. This could be a good interim solution for regions like California, which may resurrect their zero emissions mandate, until cheaper, longer lasting and faster recharging solutions emerge.
[Source: Engineair Research and Development]