The essential function of the ignition coil is the delivery of high voltage, which jumps between the centre and ground electrode of the spark plug within a cylinder, generating the ignition spark.

In the ignition process, the ignition coil plays a vital role in providing reliable ignition, allowing for the smooth and efficient operation of the engine.

The fundamental principle is the same for all ignition coils: A voltage in the high kilovolt range – up to 45,000 volts in modern vehicles – must be generated from a low battery voltage of 12 volts. Therefore, the voltage is transformed and multiplied. This principle relates to traditional cylinder ignition coils and modern block ignition coils or pencil coils.

NGK Part Numbering System.