The combustion stroke The exhaust stroke. You can see in the figure that a device called a piston replaces the potato in the potato cannon. The piston is connected to the crank shaft by a connecting rod . This is the intake stroke . Only the tiniest drop of gasoline needs to be mixed into the air for this to work.
Compression makes the explosion more powerful.
When the piston reaches the top of its stroke, the spark plug emits a spark to ignite the gasoline. The gasoline charge in the cylinder explodes , driving the piston down. Once the piston hits the bottom of its stroke, the exhaust valve opens and the exhaust leaves the cylinder to go out the tail pipe. Now the engine is ready for the next cycle, so it intakes another charge of air and gas. In an engine the linear motion is converted into rotational motion by the crank shaft.