This was in my feed recently. Rotary Diesel: Power Without Pistons It is about the recent diesel rotary prototype from LiquidPiston LiquidPiston that is partially funded by DARPA. They are also developing a small gasoline one, and seem to be more focused on applications beyond cars; tools, generators, UAVs, etc. In a Wankel rotary, the 'cylinder' is an oval space, and the rotor is a rounded triangle on an offset mount. The rotor divides the space into three sections; an intake, ignition, and exhaust. As it spins, the volume of those spaces changes, which work as the compression and expansion of a piston engine. There is no valves for intake and exhaust. Instead, the ports are opened and closed by the motion of the rotor. In the LiquidPiston rotary, the rotor is an oval, and the 'cylinder' is trilobed to accommodate the rotor. Where a Wankel rotor is analogous to one piston and cylinder, the LiquidPiston is three. Each lobe of the space works like a cylinder, and the ends of the oval rotor work like a piston. Instead of having the intake and exhaust channels in the engine block like in a Wankel and piston engine, they are in the rotor itself. The Wankel is on the left. DARPA awards additional $2.5M to LiquidPiston for development of 30kW X4 rotary diesel engine prototype - Green Car Congress LiquidPiston's site has a video. How It Works | LiquidPiston Including this because it has links and videos for those wanting to know more about how a Wankel works. Mazda Might Actually Be Onto Something | CleanTechnica
