Skip Navigation

Select Language


Knowing Ignition Coil


Operation of Ignition Coils in The Spark-Ignition Engine

Optimum ignition of the compressed fuel / air mixture has been one of the greatest challenges for designers since the early days of engine construction. In the case of ignited sparked engines, this conventionally occurs in sequence with the compression cycle by an electrical spark from the spark plug. So that the voltage can make the jump between the electrodes, a charge must first be accumulated by the vehicles' low voltage electrical system, then stored and finally discharged at the spark plug at the ignition timing. This is the job of the ignition coil as an integral part of the ignition system.

An ignition coil must be exactly attuned to the respective ignition system. The required parameters include:

  • The spark energy, which is available to the spark plug
  • The spark current at the time of the spark discharge
  • The combustion duration of the spark at the ignition plug
  • The ignition voltage under all operating conditions
  • The spark count at all speeds


Ignition coils: electrical, mechanical, thermal, electrochemical requirements

  • Temperature range -40 °C to +180 °C
  • Secondary voltage to 45,000 V
  • Primary current 6 to 20 A
  • Spark energy 10 mJ up to approx. 100 mJ (at present) or 200 mJ (future)
  • Vibration range to 55 g
  • Resistance to gasoline, oil, brake fluid

Genuine Vs Fake

Copies of ignition coils are often cheap – but they are also cheaply made. For reasons of costs and due to a lack of know-how, manufacturers of such cheap products cannot match the quality standards, which Champion offers. Most copies are made of low-quality materials and are cobbled together from a large number of individual components. They do not have the electrical properties and thermal load capacity of original ignition coils. Specifically in the case of coils with integrated electronics, copies only work properly in a few engine versions. Furthermore, they are often produced without reliable quality checks.

The content contained in this article is for informational purposes only and should not be used in lieu of seeking professional advice from a certified technician. We encourage you to consult with a certified technician if you have specific questions or concerns relating to any of the topics covered herein. 

Related Stories