Are you familiar with basic engine parts?
Basic engine parts
If you’re like most of us, the only things you recognise when you open the hood of your car are the oil dipstick and the water reservoir. So when you go to a mechanic, it can be really difficult to decipher what sounds like gobbledegook.
Fear not! Here is a quick and easy guide to explain what all that stuff under the hood is doing there.
First up, it’s going to be useful to know how your car’s engine works.
The main purpose of an engine is to convert petrol into motion so that your car can move. It does this by burning a small amount of petrol in an enclosed space. That’s why it’s called an ‘internal combustion engine’.
When petrol burns it creates gasses that take up much more space than the petrol did. In an enclosed space, like a car cylinder, this creates pressure that can be turned into movement. If you do this over and over again, hundreds of times a minute, this movement can actually propel something as heavy as a car or truck.
Almost all cars currently use what is called a four-stroke combustion cycle.
The four strokes are:
- Intake stroke: a tiny drop of petrol is mixed with air in a cylinder.
- Compression stroke: a piston compresses the air and fuel in the cylinder.
- Combustion stroke: a spark ignites the mixture, which explodes, forcing the piston back up.
- Exhaust stroke: the exhaust valve opens to let the gas out.
Here are all the parts of the engine involved:
Cylinders
The cylinders are the core of your engine. Most cars have more than one, and they can be arranged in a single row (inline), at an angle to each other (V), or horizontally opposite one another (flat).
Spark plug
This supplies the spark that ignites the air/fuel mixture.
Valves
Your intake and exhaust valves let in the air and fuel and let out exhaust fumes. Both valves are closed during the compression and combustion strokes.
Piston
This is the cylindrical piece of metal that moves up and down inside the cylinder.
Piston rings
These seal the outer edge of the piston and the inner edge of the cylinder. They keep the the air/fuel mixture and exhaust in the combustion chamber from leaking out during compression and combustion. They also keep oil from leaking into the cylinder.
TIP: If your car constantly needs oil, it’s probably because your piston rings are old and no longer seal properly.
Crankshaft
The crankshafts convert the up-down motion of the pistons into a circular motion.
Connecting rod
The connecting rod connects the piston to the crankshaft. It rotates at both ends so that its angle can change as the piston moves and the crankshaft rotates.
Sump
The sump surrounds the crankshaft. It contains oil, which collects in the bottom of the sump. If your piston rings are old, this oil can leak into the cylinder.