Researchers at Michigan State University have built a prototype internal combustion engine that requires no transmission, crankshaft, pistons, valves, fuel compression or cooling system. Their "Wave Disk Generator" could greatly improve the efficiency of gas-electric hybrid automobiles and potentially decrease auto emissions up to 90% compared with conventional combustion engines.

The engine has a rotor equipped with wave-like channels that trap and mix oxygen and fuel as the rotor spins. These central inlets are blocked off, building pressure within the chamber, causing a shock wave that ignites the compressed air and fuel to transmit energy.

The Wave Disk Generator uses 60% of its fuel for propulsion compared with standard car engines which use only around 15%.

Michigan State’s team of engineers hope to have a car-sized 25-kilowatt version of the prototype ready by the end of the year.