Technical report on ignition system.

21-06-2019 - Reports

Technical report on ignition system.

Ignition system

1. What are the functions of ignition system.
1.1. How ignition system works.
1.2. What is ignition system.
2. What is an ignition coil.
2.1. What is the structure of an ignition coil like.
3. What are ignition cables.
3.1. Types of ignition cables.

The function of the direct ignition system (DIS - Direct Ignition System) is to generate high enough voltage to cause a spark in each of the spark plugs and to initiate combustion process in the engine. The element that generates the said voltage is the ignition coil, and those in charge of transmitting the voltage to the spark plug are the spark plug wires.

The operation of the ignition system starts with the ignition switch, an element widely known by any user of vehicles. When the ignition process is started by turning the ignition key, a primary circuit connected to the battery is activated.
When this primary circuit is activated, the ignition coil provides the necessary voltage so that the spark plugs generate the spark that ignites the fuel and air mixture.
The plates are responsible for increasing the voltage caused by the coil even more. The voltage required for a spark plug to start combustion is 25,000 volts. Once the necessary voltage for the correct functioning of the spark plug has been reached, it is transported through the spark plug wires to the spark plug.
Diagram of the ignition system (DIS - Direct Ignition System).


Ignition system is composed of the following components:

  • Battery.
  • Ignition key.
  • Ignition coil.
  • Distributor (rotor, cap and shaft).
  • Contact breakers.
  • Capacitor.
  • Spark plug wires.
  • Spark plug.

Ignition coil and FAE spark plug wire.

FAE has ignition coils and spark plug wires among its wide range of products.


The ignition coil is an electromagnetic induction device. It is an element that has the function of raising the voltage in order to achieve an electric arc or spark in the spark plug.
Normally, the combustion engines have installed between 2 and 4 injection coils depending on the number of cylinders available to the engine.
Within injection coils, it is necessary to differentiate between that of ignition and that of coil. There are 4 types of ignition:
● Conventional ignition (by means of a switch).
● Capacitor discharge ignition
● Electronic ignition without contact, also called "transistorised".
● Integral electronic ignition, DIS ignition system.

On the other hand, there are several types of coils:

  • Cartucho / Asfáltico - Bottle coils. 
  • Chispa simple - Single ended coils.  
  • Bloque / Plásticas / Múltiples - DIS ystem.
  • Regletas /Cassete - Coil rail.
  • Con conector - Plug top coil.
  • Con eje - Pencil coil
FAE ignition coil and spark plug cable.

On the other hand, there are several types of coils:


The ignition coil consists of two circuits, a primary and a secondary, with a ratio of turns from 1 to 1000 approximately, with thicknesses inversely proportional to said lengths, and a ferromagnetic core.
There are two connections to the primary: one of positive power from the ignition contact of the engine, and one of negative to the cyclic interruption device.
The secondary has a ground connection and another high voltage output to the spark plug or, when applicable, to the distributor, which subsequently connects with the spark plugs of the engine.
As a general rule, the material of which a coil is composed of is:
  • Plastic / PVC (Polyvinyl Chloride): the material used for most of the coil, forming its housing.
  • Silicone: Mostly used in connection areas, such as tubes.
  • Resin: A type of thermal resin that prevents electric arcs.
  • Metal: Inside the coil, copper is used for winding and on the outside, several metallic parts are used to strengthen the structure.

The function of ignition cables is to connect the distributor or the ignition coils with the spark plugs, so that the electric current can flow and generate the resulting spark in the spark plug, which will create combustion inside the cylinder, allowing the engine to operate.
Although spark plug wires may seem very simple and maintenance-free, attention should be paid to them as, over time, they can deteriorate and adversely affect the operation of an engine and the consumption of fuel. They are essential for there to be an optimum spark in the spark plug. It should be kept in mind that the ignition system works at high voltage, approximately between 10,000 and 30,000 volts.
This product transmits the voltage of the coil to the spark plug. It must be a wire that withstands a very high voltage and does not deteriorate easily.


 FAE ignition cables.


There are three types of ignition cables, which are differentiated by the type of conductive material used, as well as by the type of resistance they need to suppress interference.
  • Copper ignition cable with interference-suppression resistor:
Copper is a good conductor, but it has little resistance to corrosion and hence the core of copper is tinned. The tin layer prevents copper from oxidising. The copper core is surrounded by a silicone coating and works as an electrical insulator, which withstands around 220ºC. These ignition cables with copper ignition core have no own antiparasitic resistance, but they are integrated in the form of molten glass with conductive elements in the spark plug and coil pipe.

  • Carbon resistor ignition cable:
Inside a carbon resistor ignition cable, there is fiberglass-impregnated carbon. The core is surrounded by two layers of silicone and fiberglass fabric. The silicone inner insulation gives the wire more rigidity and works as an electrical insulator. The fiberglass fabric gives the wire more strength.

  • Inductive reactance cable:
The inside of this type of ignition cables is similar to that of carbon core wires. On the fiberglass, there is a layer of magnetic conductive silicone surrounded by a stainless steel wire. As in a coil, an induction voltage (electromagnetism) is generated here.

Both families are included in the CE catalogue where our customers can find images of the products, detailed information about the vehicles and cross references with OEM