Those attending the DoE's Advanced Research Projects Agency – Energy (ARPA-E) Energy Innovation Summit a few weeks back got to see something called a wave-disk generator, or WDG, said to use about 60% of the fuel it burns for propulsion, which compares favorably to the 15% of fuel directed toward propulsion from conventional internal combustion engines.
The wave disk engine is the product of a Michigan State University research team led by Norbert Mueller, an associate professor of mechanical engineering. The researchers have been working on the idea for the past three years and aim to produce a vehicle-size engine/generator.
The engine gets its name from the wave-like pattern making up channels on its housing. Fuel and air enter and mix through inlets at the center axis of the device. The rotor then spins and blocks the exit of gasses. Pressure builds in the combustion chamber, eventually generating a shock wave that will compress the mixture. Once it is ignited, apparently via a process analogous to that in diesel engines, an outlet opens to let the hot gases escape.
Proposed fuels for the device are compressed natural gas or hydrogen. Positioning magnets and coils around the perimeter of the engine generate electrical power as it spins. The goal is to generate 25 kW this way.
Researchers say the WDG also can reduce carbon dioxide emissions by as much as 95% compared to modern internal combustion vehicle engines. In hybrid vehicles, the WDG could replace not just the ICE and generator, but also eliminate the need for the radiator/water pump, fuel/air control, and transmission, researchers claim.
Michigan State University put out a press release and video on this work: http://news.msu.edu/story/7036/#
Here is the program for the ARPA-E Energy Innovation Summit: http://www.ct-si.org/events/EnergyInnovation/ARPA-E_2011_Book1_web.pdf