An ignition coil is a crucial component in the ignition system of a vehicle. Its main function is to convert the low voltage from the battery into the high voltage needed to create the spark that ignites the fuel-air mixture in the engine's cylinders. This process is essential for the engine to start and run smoothly.
The basic structure of an ignition coil consists of two coils of wire, the primary and secondary winding, placed next to each other around a metallic core. The primary winding has a few hundreds of turns of thick wire, while the secondary winding has thousands of turns of thinner wire. This construction allows the coil to facilitate the transformation of the battery's low voltage (typically 12 volts) into the high voltage (about 25,000 volts) required to generate a spark.
The function of an ignition coil can be divided into two main phases: charging and firing. During the charging phase, a low voltage current from the battery flows through the primary winding of the coil. The metallic core within the coil acts as an electromagnet, increasing the magnetic field around the primary winding. This causes the energy stored in the primary coil to increase. The charging phase is essential to build up the necessary energy to produce a powerful spark.
Once the energy is stored in the primary winding, it is then released during the firing phase. When the power supply is suddenly cut off, the magnetic field collapses, causing electrons to flow from the primary to the secondary winding. This sudden movement of electrons creates a high voltage within the secondary winding, which then travels to the distributor and ultimately to the spark plugs.
The distributor is responsible for directing the high voltage to the correct spark plug, based on the engine's firing order. As the high voltage reaches the spark plug, a spark will jump across the gap between the electrodes, igniting the fuel-air mixture in the engine's cylinder.
An efficient ignition coil is vital for the proper functioning of an engine. If any component of the ignition coil, such as the primary or secondary winding, is damaged or worn out, it can affect the performance of the engine and even prevent it from starting. In older vehicles, an ignition coil could fail due to excessive heat, but modern ignition systems are designed to last the lifetime of a vehicle.