What happens when you accelerate?
Do you know what exactly is going on on the inside of your car when you accelerate?
You’ve probably heard of something called a carburetor. Until recently, I was under the impression that all cars had one (whatever it was). A carburetor is something that mixes the right amount of fuel with the right amount of air, ensuring an engine runs properly.
However, unless your car is really old, it doesn’t have a carburetor. Carburetors simply weren’t capable of doing all the complicated things modern engines have to do to provide maximum fuel efficiency and limit emissions. These days cars have fuel injection systems.
So here’s what happens when you step on the accelerator:
- The accelerator pedal is connected to a throttle valve, which lets air into the engine. Stepping on the pedal lets more air into your engine.
- The computer that controls your engine (the Engine Control Unit or ECU) senses that you’ve increased their air flow and immediately increases the flow of fuel through the fuel injector valve.
- Pressurised fuel squirts out through a nozzle that turns it into a fine mist that will burn easily.
- The amount of fuel supplied depends on how long the fuel injector stays open. This is called the ‘pulse width’.
- The ECU has sensors to monitor the air entering the engine and the oxygen in the exhaust to fine tune the fuel delivery.
Did you know? Performance chips are made by aftermarket companies to boost engine power. They replace the chip in the ECU that controls the fuel injection and make the fuel injection system supply more fuel in certain driving conditions.