Internal combustion engines are used to produce mechanical power from the chemical energy contained in hydrocarbon fuels. The power-producing part of the engine’s operating cycle starts inside the engine’s cylinders with a compression process. Following compression, the burning of the fuel-air mixture releases the fuel’s chemical energy and produces high-temperature, high-pressure combustion products. These gases expand within each cylinder and transfer work to the piston, producing mechanical power to operate the engine.
Each upward or downward movement of the piston is called a stroke, and the two commonly used internal combustion engine cycles are the two-stroke cycle and the four-stroke cycle. The terms “two-cycle” and “two-stroke,” as well as “four-cycle” and “four-stroke,” are often interchanged.
See the October AMSOIL Magazine for more information.
