In the previous article we have learned about the types of ignition systems. Today we will focus on the distributor-less ignition system, including two main branches, which are Coil-Near-Plug ignition system and Coil-On-Plug Ignition system.

CNP(Coil-Near-Plug)

This ignition system eliminates the distributor entirely. Instead, coil packs (multiple ignition coils) are used, one for each pair of cylinders(such as Chevy ignition coil,DIS coil pack serves two cylinders) . One coil serving two spark plugs (for example two coils in a four-cylinder engine ,as shown below:  Volvo ignition coil pack. Three coils in a six-cylinder engine,as shown below: Honda ignition coil pack). A combination of two cylinders using a single ignition coil, so this ignition can only be used on engines with an even number of cylinders.

The spark timing depending on two shaft position sensors and a computer. The crankshaft position sensor (CKP) locates near the flywheel in some vehicles. The sensors monitor the shaft position and send this information to the computer. The DIS utilizes multiple ignition coils known as coil packs with each generating spark for two cylinders.

The Distributor-less Ignition System is also known for being less expensive when you are looking for an ignition system offering high voltage at a low price. In short, it is a better alternative for those looking to get an ignition system without spending too much. Ignition system for two cylinder engines.

This type of ignition system is connected in series between spark plugs. Ignition is carried out twice in two different cylinders simultaneously. One cylinder is on its compression stroke, and the other is on its exhaust stroke. The spark plugs that fires during the compression stroke creates power. The plug that fires during the companion cylinder's exhaust stroke is "wasted"; this is because it fires into exhaust gases.

Coil-On-Plug Ignition System

The Coil-On-Plug (COP), also known as direct ignition systems. However, instead of two cylinders sharing a single coil, each coil in the Coil-On-Plug ignition system utilizes a single cylinder. It has twice the time to develop the maximum magnetic field. Some vehicles with the COP can generate 40,000 to 50,000 volts and stronger sparks. The coil mounts directly on the top of spark plug, which eliminates the high-tension wire.

Highly accurate ignition is achieved by monitoring cylinder compression and camshaft sensors. It is suitable for engines with any number of cylinders, especially those with four valves per cylinder. Because assembly (spark plug and ignition coil) can be installed in the middle of the double overhead camshaft (DOHC), the gap space is fully utilized. Due to the absence of the distributor and high-voltage wire, the loss of energy conduction and leakage is minimal, and there is no mechanical wear. Moreover, the ignition coil and spark plug of each cylinder are assembled together and wrapped with metal, greatly reduces the electromagnetic interference, which can guarantee the normal operation of the engine electronic control system.

Warm tips:

The coils inside this type of ignition system are at risk of damage by degreasers and water during cleaning engine. Hence, you need to protect them before any cleaning.