How Ignition Distributor Works?

Ignition Distributor

Here you can get Ignition Distributor Working Principle. Ignition distributors are used in battery ignition system, magneto ignition system as well as in electronic ignition system.

A distributor is an enclosed rotating shaft utilized in spark-ignition internal combustion engines that have mechanically timed ignition. The distributor’s primary feature is to direction secondary, or excessive voltage, current from the ignition coil to the spark plugs in the correct firing order, and for the correct amount of time.

What is Ignition Distributor ?

Ignition Distributor is a mechanical device which is used to transfer the excessive voltage current produced by the secondary coil to the correct spark plugs in correct firing order and in correct quantity of time.

It has a mechanically-timed ignition. It was the year 1910 wherein the primary reliable battery operated ignition system was developed by Delco (Dayton Engineering Laboratories Co.). And this ignition was evolved by Charles Kettering.

Working of Ignition Distributor

  1. As the ignition distributor shaft rotates, it rotates the cam and rotor.
  2. When the cam pushes the cam follower of the contact breaker, the contact factors of the contact breaker opens and collapses the primary current through the primary winding.
  3. This produces a excessive voltage current in the secondary winding. The excessive voltage current produced is transfer to the distributor’s relevant terminal.
  4. The current from the relevant terminal reaches to the outer edges of the rotor thru the carbon bush. As the rotor is available in the front of the internal terminal of the spark plug in the distributor cap, the high voltage electric pulses (or surge) pass to the spark plug and it produces a spark within the cylinder head.
  5. The distributor produces spark in every of the spark plug in in correct sequence and in correct amount of time.
  6. In this way, the ignition distributor works.

Main Parts of Ignition Distributor

1. Distributor Cap

It is a cover which protects the internal parts of the distributor. It has one post for every cylinder and in touch factors kinds ignition system it additionally has one central post which is connected to the ignition coil to receive the current from it.

Some engines have spark plugs consistent with cylinder; in that case, the distributor has leads consistent with cylinder. In the wasted spark system, a single contact is used for two leads, however every lead connects one cylinder.

In General vehicles where the high energy ignition (HEI) system used, there’s no central post in the distributor cap. The ignition coil is placed on the top of the distributor. Inside the distributor cap, the plug terminals are organized around the circumference of the cap at the foundation of the firing order in order that the secondary voltage-current must be sent to the correct spark plug at proper time. The rotor rotates inside the distributor cap.

2. Rotor

The rotor is present at the top of the distributor shaft. It is driven by the camshaft of engine and for this reason synchronized to it. The rotor is pressed towards a carbon bush at the important terminal of the distributor cap. The important terminal of the distributor is connected to the ignition coil.

The rotor is made in such a way that its central tab is electrically connected to its outer edge so the current that is coming into the central terminal travels thru the carbon bush point to the outer edge of the rotor.

As the camshaft rotates, it rotates the distributor shaft. Due to this the rotor connected to the distributor shaft also starts rotating. When the outer fringe of the rotor passes to every inner plug terminal in distributor cap, it fires every spark plug in accurate sequence.

3. Contact Breaker

It is mechanically designed breaker point. Its one end is fixed and other end is movable. It is connected to the breaker assembly. Its main function is to makes and breaks the primary circuit current.

When the lobes of the cam pushes the cam follower of the contact breaker, the factors of the breaker which have been touching every different moves apart and breaks the primary current to flow through the primary winding of the ignition coil.

4. Distributor Shaft

It is a shaft which lies in the center of the ignition distributor. It is connected directly to the camshaft of the engine thru a gear drive. It includes a cam that is used to break the factor of the touch breaker.

5. Cam

It is connected to the distributor shaft and rotates with it. It has lobes that are used to open the touch breaker point. The number of lobes is same to the number of engine cylinder. As the cam rotates, it pushes the cam follower and the breaker factors actions aside leads to breaking of current.

6. Capacitor

It is used to prevent the overheating of the contact point of the contact breaker. It helps in production of high voltage current by reverse the current flow through the primary coil.

7. Spark Advance Mechanism:

It is a mechanism that’s used to advance the spark in the spark ignition engine. We have normally kinds spark advance mechanism and i.e. centrifugal advance spark and vacuum spark advance mechanism.

Its most important feature is to ignite the fuel before the piston reaches the TDC. This allows the complete burning of the air-fuel mixture with in the cylinder and results in the most pressure on the piston.


Ignition distributors are used in battery ignition system, magneto ignition system as well as in electronic ignition system.


No comments yet. Why don’t you start the discussion?

Leave a Reply