+ Submit your article here

How Does a Petrol Engine Work?

10/1/2013 11:54:38 AM | by Anonymous

Engines: Petrol

Many people drive cars every day to go to work, but many people may not know how their engines work. A petrol engine uses internal combustion with spark ignition to operate. Unlike other engines, it is designed to run on petrol. The first engine was invented in Germany by Nicolaus August Otto in 1876. There are a numbers of variations of petrol engines. Some use direct fuel injection while others may use a carburetor. The difference between petrol engines and a diesel engine is that diesel engine do not use spark plugs and rely on heated compressed air for it to ignite, whereas petrol engine uses spark plugs to ignite the fuel. Petrol engines also enable the car to run at higher speeds, which may be due to the fact that the parts of an engine are lighter. However, a petrol engine does consume more fuel making it less efficient.


Parts of the engine


In order to understand properly how the petrol engine works through internal combustion, it is important to have a rough understanding of the basic engine parts first. The core of a petrol engine is known as a cylinder which contains the moving pistons. Depending on the manufacturer, the number of cylinders may vary according to the type of configuration the manufacturer wishes to implement. Different types of configurations will bring about different types of disadvantages or advantages.


The first part would be a spark plug. The spark plug creates a spark that ignites the air and fuel mixture so that internal combustion can occur. The next part would be the valves. There are two types of valves, the exhaust and intake. The intake valve allows the air to enter the petrol engine at the right time. The same concept applies to the exhaust valve, which allows air to release at the right time.


The next part would be the piston which fits perfectly in the cylinder. The pistons move in a vertical motion. On the pistons, piston rings are also included to act as a seal to prevent the fuel and air mixture from leaking out to the rest of the engine.


The pistons are connected to the crankshaft through a connecting rod. The connecting rod is able to rotate at the ends at an angle as the pistons move in a vertical motion where as the crankshaft moves in a circular motion. The crankshaft is then connected to the axis of the wheels.

Internal combustion


Petrol engines are classified under internal combustion engines. Internal combustion engines ignite the petrol in a small confined area, whereby a large amount of energy is released as a result of the expanding gas. However, having the energy is useless if it is not transferred efficiently. This is where the four stroke combustion cycle is important.


The four strokes are the intake stroke, compression stroke, combustion stroke and exhaust stroke. The intake stroke is when the intake valve takes in the air and the air is mixed with a tiny amount of fuel. Before the mixture is ignited, the air is compressed by the piston moving up. This is known as the compression stroke. When the air and fuel mixture can no longer be compressed, the spark plug generates a spark which ignites the air and fuel mixture causing a small explosion. This is known as the combustion stroke.


By compressing the air and fuel mixture it intensifies the combustion and explosion which in effect releases more energy. This sudden expansion of air sends the piston down at high speeds. The final stroke is the exhaust stroke. This is when the exhaust valve releases the unwanted air after the combustion process.


The pistons will constantly be moving up and down due to this process and the energy produced by this is converted into circular motion through the connecting rod between the pistons and the crankshaft. The energy created by this circular motion is attached to the axis which ultimately moves the car forward.


This is the basic process of how a petrol engine works through internal combustion. Thanks to Nicolaus Otto, we are able utilize the engine for many industrial applications and also for our own leisure.

Are you sourcing for a product or service?

Do you need a quotation?