What is the function of the ignition coil?

The ignition coil plays a crucial role in automotive engines. Its core function is to convert the 12V low voltage of the vehicle power supply into high voltage up to 15-20kV. This conversion process is crucial because high-voltage electricity is further converted into high-voltage sparks through spark plugs, igniting the combustible mixture inside the engine and allowing the car to start and run continuously. 

The reason why the ignition coil can achieve this voltage change is because its internal structure is similar to that of a regular transformer, both containing primary and secondary coils, and the difference in the number of turns between the two is relatively large. However, unlike the continuous operation of ordinary transformers, the ignition coil operates in an intermittent manner. It will store and release energy at different frequencies based on engine speed. 

During the operation of the ignition coil, when the primary coil is powered on, the increase in current will generate a strong magnetic field around it and will create magetic field energy to be stored by the iron core. When the switching device cuts off the circuit of the primary coil, the magnetic field rapidly decays, and a high voltage will be induced at the secondary coil. The faster the magnetic field of the primary coil disappears, the greater the current at the moment of current disconnection, and the greater the turn ratio of the two coils, and the higher the voltage induced by the secondary coil.