Which stroke occurs when fuel ignites and pushes the piston down?

The power stroke is the phase of an engine's cycle where combustion occurs and the explosion of fuel ignites, creating high-pressure gases that push the piston down. This stroke is a critical part of the engine's operation, as it is where the conversion of chemical energy from fuel into mechanical energy takes place.

During this stroke, the piston is at the top of the cylinder, and as the fuel-air mixture ignites, the rapid expansion of gases results in the piston's downward movement. This downward force is what ultimately translates into power being delivered to the crankshaft, enabling the vehicle to move.

In contrast, the intake stroke involves the intake of the fuel-air mixture into the cylinder, the compression stroke compresses this mixture to prepare it for ignition, and the exhaust stroke expels the burnt gases from the combustion chamber. Each of these strokes has its own specific role in the engine cycle, but it is the power stroke that directly relates to the ignition of fuel and the resultant movement of the piston.