Two-stroke cycle

The operating principle of an internal combustion engine characterized by the fact that the intake, compression, combustion, and exhaust phases overlap and require only two cycles; used mainly by some motorcycle engines. On cars, the two-stroke engine was never very popular and was never produced in the USA (although Ford is experimenting with the engine); a new two-stroke engine concept with separate lubrication system and a valve system similar to four-stroke engines may combine the benefits of both the 2-stroke and the 4-stroke systems. Two-stroke engines have the advantage of rapid low-end torque (because it gets its power stroke twice as often) while 4-strokes are better at sustained high-speed.