Ignition coils are used to create a spark at the spark plug to instigate combustion in an internal combustion engine. The ignition coil is basically a transformer that coverts the low level voltage from the battery into the much higher voltage required to jump the spark plug electrodes.

Traditionally ignition coils where ‘wet’ coils, they consisted of some primary windings of several turns of a thick wire and then 1000’s of turns of a much thinner wire wrapped around an iron core, this was then put into a case and filled with oil to provide insulation and heat dissipation.

Although all ignition coils use this same principle they have evolved over time and a typical modern ‘dry’ coil utilises the same transformer setup but the casing around it is filled with epoxy resin to provide the insulation and heat dissipation.

Many modern vehicles use a coil per cylinder setup, this means that each spark plug has its own coil directly attached to the top of it thus providing a very efficient spark whilst removing the need for HT leads. These compact coils often use rare earth magnets in the central core to increase output voltage and maintain a strong spark in the limited physical space available.

SMP Europe's coil-on-plug assemblies are engineered and tested to meet or exceed OE standards for spark energy, impedance, and durability. The core has an internal neodymium permanent magnet surrounded by grain-oriented magnetic laminated steel for maximum voltage output at all speeds.

The primary winding has a 200°C insulated coating over a premium 25 gauge copper wire, allowing low voltage to generate a strong magnetic field. A high temperature insulation coating prevents shorts between the windings under extreme operating conditions.

The bobbin is made from fibre reinforced polyphenylene oxide glass material which has outstanding dielectric properties to keep the voltage directed along the correct path providing long life under extreme high-voltage conditions.

The high impact case is tough and durable with excellent thermal qualities and the high temperature spark plug boot contains a conductive stainless steel spring with radio static noise suppressor both are built for long life in all operating conditions.

The ignition coil converts a low voltage current to high voltage energy that is delivered to the spark plug to ignite the air fuel mixture within the cylinder. A coil-on-plug is designed to perform the functions of both the ignition coil which creates the spark energy, and the spark plug wire set that is designed to contain and deliver the high voltage energy to the spark plug.