The Jumo engine is being developed by a California based company under contract to the US Army, who want something to power their tanks and other vehicles more efficiently.
The unusual design of the engine has no cylinder head. Instead there are two pistons in the cylinder which compress the fuel between them, and then fly off in opposite directions after ignition.
A single cylinder experimental version has already shown promise in a laboratory, and the US Army is putting $4.9m behind bringing the experiment to the next level, a multi-cylinder engine.
The engine is capable of running on a wide range of fuels, from jet fuel to diesel. While this is a defence contract, there's a long history of successful military developments spilling out into consumer applications, so it could well be that we'll see a variation of this in the future powering our cars and trucks.
