How does a car engines motor work?

"Car" engines use controlled explosions (depending on how many cylinders) to convert straight line motion into rotating motion.

The pistons in an engine (straight line motion) are driven downward due to the force created by the explosion of gasoline and air. The explosion is triggered by a spark caused by the spark plug.

The force of the explosions are transmitted from the pistons to the connecting rods, then the crankshaft. (rotating motion) From there to the Transmission and finally, the Wheels.