How does fuel injector works in petrol engine?

- May 12, 2020-

Please do not get confused between the Diesel Engine Fuel Injectors and Petrol Engine Fuel Injectors as they are poles apart and run on different Combustion cycles altogether.

In a petrol engine, fuel injectors can be used in a numerous ways.

  • It can be used in the intake manifold before the Intake valve or

  • It can be used in the cylinder after the intake valve.

But Spark plugs are mandatory for a Petrol Engine, unlike Diesel Engines, where fuel gets ignited due to compressed air only.

In a petrol engine, the air is taken inside via the air filter, and a metered quantity of fuel is sprayed by the injectors as the air gushes in the cylinder via the intake valves. And an air-fuel mixture is formed which is later ignited by the spark plugs.

On the contrary, in a diesel engine, the fuel is injected inside the cylinder at the end of the compression stroke, and the fuel gets ignited resulting in the power stroke.

I have written this answer in a nutshell, but if you are really interested on how engines work, I recommend reading any book on Applied Thermodynamics. Your concepts will get clearer.