The accelerator pedal manages the throttle valve which controls the flow of air in your engine and in turn dictates the amount of fuel released into your engine. Ultimately the accelerator pedal, by regulating the air and fuel flowing into your engine, controls the speed at which your car travels.
The accelerator pedal is located in the footwell of your car. It is the pedal on the right hand side next to the brake pedal.
When you press down on the accelerator pedal, this causes the throttle valve to open up, allowing more air to flow in. The engine control unit recognizes that the throttle valve is open and in turn regulates the amount of fuel entering the engine in readiness for the increased flow of air in the engine. In essence, when you press the accelerator pedal with your foot, this makes your car go faster.
In a worst case scenario, the accelerator pedal can malfunction and get stuck fast, but this is rare. accelerator pedals do wear down over time, however, and you will eventually need to buy a new part for your car. Symptoms of this will include a sticky accelerator pedal or one that is harder to press down with your foot. A faulty accelerator pedal can get sticky when the throttle valve it connects to, which lets the air into the engine, gets clogged up with waste carbon. Generally speaking, if the compression of your foot on the accelerator pedal is not a smooth and easy process then you should ask your mechanic if it needs a replacement.