Ignition System

So, the ignition system has evolved over the years, to create at least 4 different types.

Even though they are, completely different, they actually all have the same goal.

Most importantly, to take a low voltage and turn it, into a high voltage.

Consequently, allowing the spark plug, to ignite the air and fuel mixture, at the correct time.

Some of these ignition system types include:

  • Distributor-Based Breaker-Point Ignition (Mechanical)
  • Distributor-Based Electronic Ignition
  • Distributor-less Ignition
  • Coil-On-Plug Ignition

So, an ignition system, is divided into two electrical circuits:

  • The Primary Circuit.
  • The Secondary Circuit.

Primary Circuit

So, the primary circuit, only carries, the low battery voltage. This circuit, is controlled by, the breaker points and the ignition switch.

When the ignition key is turned on, a low voltage current from the battery flows:

  • First, through the primary windings, of the ignition coil.
  • Next, through the breaker points and back to the battery.

This current flow, causes a magnetic field to form around the coil.

Secondary Circuit, Ignition System

So, the secondary circuit, consists of the secondary windings, in the coil. And, it includes a high tension lead, between the distributor and the coil, on external coil distributors.

Other parts included:

  • Distributor cap.
  • Distributor rotor.
  • Spark plug leads (wires).
  • Spark plugs.

As the engine rotates, the distributor shaft cam, also turns. And, after it reaches the high point on the cam; it causes the breaker points to separate.

So, the current flow stops, when the points open. As a result, this causes the magnetic field to collapse around the coil. In addition, the condenser absorbs the energy and prevents arcing; between the points each time they open. Finally, this condenser also aids in the, rapid collapse of the magnetic field.

Distributorless Ignition System

So, with distributorless ignition, the spark plugs are fired, directly from the coils. Furthermore, spark plug timing is controlled by, an ignition module and the engine computer. The distributorless ignition system, may have; one coil per cylinder or one coil, for each pair of cylinders.

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