The ignition coil – a brilliant idea

How does the ignition coil work?

The ignition systems of motor vehicles have also benefited from the technical development of recent years. Depending on the vehicle models of the respective vehicle generation, there are different methods for transferring the high-voltage energy gained with the help of the ignition coil to the spark plug. For example, before the introduction of fully electronic ignition, a mechanical ignition distributor was interposed. In the meantime, ignition coil and spark plug are usually directly connected to each other without an intermediate distributor. The functional principle of an ignition coil is quickly explained. It consists of a primary winding with only a few turns and a secondary winding with many turns. The amount of high voltage generated from the on-board voltage depends on the difference in the number of turns between the primary and secondary windings. In order to generate the ignition spark required to start the vehicle, the current from the on-board voltage first flows through the primary winding and builds up a magnetic field. Now all that remains is to interrupt the current flow and thus spontaneously switch off the magnetic field and the high voltage required for the ignition spark is generated in the secondary winding.

How do you notice that the ignition coil is broken?

In principle, ignition coils are durable, and replacement after a certain mileage is not necessary. Heating and cooling of the coil, combined with natural aging processes, can cause damage that causes a short circuit and prevents the coil from delivering the required high voltage of up to 30,000 V. This does not necessarily mean that the cylinders in question actually fail in every case, there may also be sporadic dropouts at first. If the high voltage generated by the ignition coils is reduced, ignition misfires initially only occur in certain load ranges of the engine – namely when the combustion pressure in the respective cylinder becomes too high. Usually, a conventional four-cylinder engine has two ignition coils, which are either designed as double ignition coils or provide fuel ignition in all combustion chambers through an ignition distributor. In the event of a defect in such a coil, two cylinders are usually also affected by slight misfires. The following symptoms are typical:

Rough engine running, jerking

 coil. In more modern vehicles, there should be a corresponding entry in the fault memory indicating a defective ignition coil. The fault should then "wander", the misfires must then occur in the other two cylinders. You should exercise appropriate caution when changing the ignition coils, because the high voltage can be quite dangerous. Before changing, it is therefore advisable to disconnect the vehicle battery. Apart from that, the replacement of this component is usually possible without any problems, even for less experienced screwdrivers.

Why does the coil need to be changed?

Without the ignition coils, combustion cannot take place in a gasoline engine. A defect is rare, but then only the replacement of the important component helps. In a gasoline engine, an ignition coil is an indispensable component: the ignition coil generates a high voltage from the 12 V on-board voltage, through which an ignition spark can be generated with the help of the spark plugs. This ignition spark ensures that the fuel-air mixture is ignited within a very short time and generates the explosion necessary for propulsion. A defective ignition coil ultimately prevents this mixture ignition from occurring and causes sometimes inexplicable disturbances.

Can you repair a defective ignition coil yourself?

By the way, repairing the ignition coil is not feasible, because the usually installed copper wires are potted, so that opening as well as possible repair attempts is hardly crowned with success. In addition, the cost of a new coil is relatively low, so that repairing the component is hardly worthwhile from an economic point of view. With us you will find high-quality ignition coils in OEM quality for almost every vehicle type. Thanks to the fast delivery, you can quickly repair your vehicle yourself or have it repaired.