How does a car engine work?Have you ever looked at your car’s engine, and wondered how on earth that mass of metal is going to propel you to your destination? Well...let’s find out.
The key ingredients used to get a car moving are fuel and an internal combustion engine. In a nutshell, a car’s internal combustion engine works by burning fuel inside it to produce energy.
The theory is this…if you put a tiny drop of high-energy fuel (like petrol) into a small, enclosed space and set it on fire, a huge amount of energy is released as an expanding gas. If you do this over and over, hundreds of times a minute, you get enough power to send tonnes of metal zipping down a highway.
The small, tightly sealed oven where the explosion happens is called a cylinder. Cars have several cylinders in their engines – a small car engine has four cylinders and the largest ones up to twelve. One end of the cylinder can open and close like a bike pump, with a tightly fitting piston inside which slides up and down inside like a coffee plunger.
The engine makes its power by repeating four steps (or strokes) over and over. Here’s what is happening inside each cylinder:
Intake – the intake valve (which is like a gate) opens and the piston moves down, bringing the air and fuel into the cylinder.
Compression – the piston moves back up and squishes the air and fuel into a smaller space.
Combustion – the spark plug creates a spark that sets the fuel on fire. The explosion forces the piston back down.
Exhaust – the exhaust valve opens to release the gas caused by the explosion.
The powerful downward motion caused by the explosion in each of the cylinders turns the engine’s drive shaft. The drive shaft is a mechanical part that typically runs the length of the car from the engine to the wheels. The turning drive shaft powers the axle and wheels, causing them to turn as well, moving the car forward.
That’s it! Now you know how your car engine works. Air and fuel are drawn into a small space and set on fire, with the explosion creating the power that makes the wheels turn. Off you go now…go show off your newfound knowledge to anyone who will listen!