How does a four stroke engine work?

A four stroke engine has four cycles. Intake cycle, compression cycle, power cycle, and exhaust cycle. Each corresponds to one full stroke of the piston; therefore, the complete cycle requires two revolutions of the crankshaft to complete.

Here is a brief explanation on how it works.

• Intake cycle

The intake valve opens, the piston moves downward and fuel and air is sucked into the cylinder

• Compression cycle

The Intake valve closes and the piston moves upward, compressing the fuel and air mixture.

• Power cycle

A spark plug ignites the fuel/air mixture and the piston is forced downwards.

• Exhaust cycle

The piston moves upward and the exhaust valve opens, letting the fumes out of the cylinder.