Exploring Automotive Ignition Systems

14-01 Categorize automotive ignition system components.

Several types of ignition systems have been in use over the years. Earlier vehicles use a contact-breaker-point ignition system that relies on mechanical devices to create the spark. Because breaker-point ignition systems are mechanical, they require regular maintenance due to wear. On later vehicles, the mechanical contact breaker was eliminated, replaced with an electronic means for connecting and disconnecting the primary circuit. Modern vehicles no longer use a distributor and instead send the high voltage from the coil packs or individual coils directly to the spark plugs.

The main difference between these systems is in the way the primary circuits are controlled to produce the secondary spark. The primary circuit is switched on and off, thus creating and then collapsing the primary magnetic field. This switching can be done with breaker points in older vehicles or by using electronic switches in modern vehicles. No matter how complicated an ignition system seems, it always has a primary and secondary circuit. Both the primary and secondary circuits require a ground to work correctly.

The Society of Automotive Engineers (SAE) refers to any ignition system that has a distributor as distributor ignition, or DI for short. Any vehicle that does not use a distributor is an electronic ignition (EI) system. This terminology can cause some confusion when referring to waste spark systems because some original equipment manufacturers (OEMs) name their system a distributorless ignition system (DIS).

These are the three most popular types of automotive ignition systems:

1. distributor
2. distributorless or waste spark
3. multi-coil direct, including coil-on-plug (COP) and coil-near-plug (CNP).