Once again, the five key events occur, but in a different way.
At the start of air intake, the piston is moving toward bottom dead center at the end of a power impulse.
The piston uncovers the inlet ports and the blower delivers fresh air into the cylinder. The exhaust valve opens. The piston reaches bottom dead center and starts its move upwards.
Incoming air scavenges exhaust gases out of the cylinder.
The piston continues up, covers the air inlet ports and cuts off the air supply from the blower. The exhaust valve closes. The piston approaches top dead center, compressing the air and raising its temperature.
Just before the piston reaches top dead center, the injector sprays in fuel. The heat of the compressed air ignites the fuel. Pressure from the expanding gases forces the piston down the cylinder in a power impulse.
Before the piston reaches bottom dead center, the exhaust valve opens and burned gases escape. The inlet port is uncovered and it admits fresh air from the blower. The piston reaches bottom dead center.
The cycle is ready to repeat itself. All five events occur in just two strokes.
How many revolutions does the crankshaft do in one engine cycle? One revolution per cycle.
