Answer for What is Power Stroke in an Engine

The compressed gases are given spark by the spark plug and ignited. As a result the gases expand and pressure of ignited gases exert on the piston because of which piston moves from T.D.C. to B.D.C. This power received by the piston is delivered to the crankshaft through the connecting rod and thus the flywheel moves. Through the flywheel, the power of the engine is used for other purposes.