In older ignition systems, the output stage was mounted as a separate component in the engine compartment on the vehicle body or – in the case of rotating high voltage distribution – in or on the ignition distributor. The introduction of static high-voltage distribution and the development of microelectronics made it possible to integrate the output stage into the ignition coil.

This results in numerous advantages:

● Diagnostic possibilities

● Ion current signal

● Interference suppression

● Power cut-off

● Current limitation

● Thermal cut-off

● Short circuit recognition

● High voltage stabilization

Double spark ignition coils produce for every two spark plugs / two cylinders each an optimum ignition voltage in different cylinders. The voltage is distributed so that.

● The air / fuel mixture of a cylinder is ignited at the end of a compression stroke (ignition time) (primary sparks – powerful ignition spark),

● The other cylinder’s ignition spark jumps in the discharge stroke (secondary sparks – low energy). Double spark ignition coils generate two sparks per crankshaft rotation (primary and secondary spark). No synchronization with the camshaft is required. However, double spark ignition coils are only suitable for engines with even numbers of cylinders. Thus in vehicles with four cylinders and six cylinders, two and three double spark ignition coils respectively are installed.

In an ignition coil rail (ignition module), multiple ignition coils – depending on number of cylinders – are arrayed in a common housing (rail). However, these coils are functionally independent and operate like single spark ignition coils. The design advantage is that fewer connecting cables are required. One compact plug connection is sufficient. Moreover, the modularity of the ignition coil rail helps make the entire engine compartment more ‘elegant’, more clearly arranged and uncluttered.

Single spark ignition coils – also known as plug shaft/connector ignition coils, rod or pencil coil or smart plug top coil ignition coils – are directly mounted on the spark plug. Normally no ignition cables are required for this (with the exception of double spark ignition coils), whereby high-voltage connectors are required.

In this design, each spark plug has its own ignition coil, which is located directly above the spark plug insulator.This design enables particularly filigree dimensions.Modular, compact, light smart plug top coil ignition coils of the latest generation are especially suited with their space-saving geometry for modern downsized engines. Even though they are more compact than larger ignition coils, they generate greater combustion energy and higher ignition voltage. Innovative plastics and the extremely safe connection technology of the components inside the ignition coil body also ensure an even greater reliability and durability.

Single spark ignition coils can be used in engines with both even and uneven numbers of cylinders. However, the system must be synchronized via a camshaft sensor. Single spark ignition coils generate one ignition spark per power stroke. Ignition voltage losses are the lowest of all ignition systems due to the compact design of the single spark coil / spark plug unit and the absence of ignition cables. Single spark coils enable the largest possible range of ignition angle adjustment. The single ignition coil system supports monitoring of misfiring in the ignition system on both the primary and secondary side. Any problems that occur can thus be saved in the control unit, rapidly read out in the workshop via OBD and specifically rectified.

Space-saving and highly efficient BERU ignition system: double platinum spark plug with Plug-Top ignition coil. The internal pressure spring ‘bowl’ connector on the new double platinum spark plug prevents insulator flashovers.