Car Engine

A car is a combination of all kinds of tehcnologies, and the heart of it, the engine, is certainly the most complex part. It works in a cycle of four steps. First, the engine let some air go into the cylinder. Then the piston squeezes the air and the gas together. This step makes burning easier and faster. Next, the engine make a little flame and the mixture of gas and air suddenly explode. The explosion pushes the piston go up and down. This action provides the energy for the car to run. Last, the engine releases the air out to prepare for the new cycle. In my opinion, the engine is always the most amazing and complicated machine in the world.