How an Auto Starter Works

An auto starter is closely tied to the structure and function of the internal combustion engine. Electricity drives your car’s spark plug to ignite a vapor of gasoline, which in turn moves the car engine’s system of pistons and valves. These operate the crankshaft that moves the wheels forward, as long as there is a continuous supply of gasoline vapor.

Ignition

The starter is what begins the engine’s combustion process, and it does this by completing a series of electrical circuits. When you place your car key in the ignition, the mechanism that it connects to is called the ignition switch, which has a certain number of different positions that can be activated by turning the key. The first three allow certain components (such as the AC) to run without draining the battery or burning out the starter, but the fourth is the most important.

Solenoid and Flywheel

Once the ignition switch is turned over to start the car, it completes the circuit to a device known as a solenoid, which pulls power from the car’s battery. This connects to a small motor at the end of the starter shaft, which in turn powers a larger gear called a flywheel on the front of the engine itself.