How does a car engine work?

A conventional car uses an internal combustion engine, which turns the chemical energy in fuel into motion through a repeating four-step cycle inside its cylinders. First, in the intake stroke, a mixture of air and fuel is drawn into the cylinder. Second, in the compression stroke, the piston squeezes this mixture. Third, in the power stroke, a spark plug ignites the compressed mixture, and the resulting explosion drives the piston down forcefully. Fourth, in the exhaust stroke, the burnt gases are pushed out. This up-and-down motion of the pistons turns a crankshaft, converting it into rotation that is ultimately transmitted to the wheels. Most engines have several cylinders firing in sequence to produce smooth, continuous power. Electric cars work very differently, using electric motors powered by batteries instead of burning fuel.