How Do Car Engines Work?

The Basics

A car engine is a machine that converts the chemical energy in gasoline into mechanical energy that can be used to power the car. The basic principle behind all car engines is the same: a piston moves up and down inside a cylinder, and the motion of the piston is converted into rotational motion by a crankshaft.

The four main parts of a car engine are the cylinder, the piston, the crankshaft, and the valves. The cylinder is a metal tube in which the piston moves up and down. The piston is a metal disk that fits inside the cylinder and is connected to the crankshaft by a connecting rod. The crankshaft is a metal shaft that rotates as the piston moves up and down. The valves are small flaps that open and close to allow air and fuel to enter the cylinder and exhaust gases to escape.

The Four-Stroke Cycle

The four-stroke cycle is the sequence of four events that take place inside a car engine during each complete rotation of the crankshaft. The four strokes are:

Intake stroke: The intake valve opens, and the piston moves down, drawing air and fuel into the cylinder.
Compression stroke: The intake valve closes, and the piston moves up, compressing the air and fuel mixture.
Power stroke: The spark plug ignites the air and fuel mixture, causing it to burn and expand. The expanding gases push the piston down, turning the crankshaft.
Exhaust stroke: The exhaust valve opens, and the piston moves up, pushing the exhaust gases out of the cylinder.

Engine Types

There are two main types of car engines: gasoline engines and diesel engines. Gasoline engines use spark plugs to ignite the air and fuel mixture, while diesel engines use compression to ignite the fuel.

Gasoline engines are more common than diesel engines in passenger cars. They are lighter and less expensive to build than diesel engines, and they produce more power for their size. However, diesel engines are more efficient than gasoline engines, and they produce less pollution.

Conclusion

Car engines are complex machines, but the basic principles behind them are relatively simple. By understanding how car engines work, you can better appreciate the engineering marvel that powers your car.