Inside an Opposed Piston Opposed Cylinder (OPOC) Engine

OPOC engines are simpler and thus less likely to break down. They're also more efficient, lose less energy while operating and can produce much more power than a standard internal combustion engine for only a portion of the gas.

The two pistons in the single cylinder are effectively interlaced, with each one divided into two parts and moving inside one another in opposite directions creating the compression stroke, so that the opposing ends of one part of each piston are closing together and compressing the fuel air mixture between them while the opposing ends of the other are moving apart to admit air in the gap to create the intake stroke.

The whole action of the pistons takes only two back and forth motions, thus making this a two-stroke engine instead of the more conventional four-stroke engine.

Because two pistons in one cylinder perform the work of the two pistons in two ordinary cylinders, they do only the work that normally goes on in one cylinder but apply two cylinders worth of motion to the crankshaft.

Ecomotors for the Defense Advanced Research Projects Agency (DARPA).