What is the primary function of an ignition coil?

The primary function of an ignition coil is to convert low voltage from the battery to high voltage. In an automotive ignition system, the battery normally operates at a voltage of around 12 volts, which is insufficient to create a spark strong enough to ignite the air-fuel mixture in the engine's combustion chamber. The ignition coil amplifies this low voltage to a much higher voltage, typically in the range of 20,000 to 45,000 volts or more. This high voltage is necessary to jump the gap at the spark plug electrodes, creating a spark that ignites the mixture and allows the engine to function properly.

By understanding the role of the ignition coil, it becomes clear that batteries do not store electrical energy for ignition purposes, fuel injection timing is a separate function managed by an engine control unit, and monitoring engine temperature is the role of sensors rather than the ignition coil. This highlights the specific and crucial function of the ignition coil within the ignition system of a vehicle.