Components of Electronic Ignition System and its working

Electronic ignition system is developed to reduce emissions, increase mileage and improve reliability. Electronic ignition system produce stronger spark which is required to burn the lean mixture in the combustion chamber. Electronic ignition systems differ from conventional ignition systems in the distributor components.

Parts

• Battery

A battery is a electrochemical device for producing and storing electricity. It supplies the necessary energy for the ignition system. Battery consists of electrodes namely anode (+ve terminal), and cathode (-ve terminal) and an electrolyte solution. Electrons flow from cathode to anode in the battery which results in potential difference.

• Ignition switch

The ignition switch enables the operator to turn the ignition system on or off in starting or stopping the engine. In any automobile the ignition switch has 4 types of operations they are

> OFF – OFF position turns off electrical system of the automobile

> ACCESSORY – This position turns on power to the entire automobile except the ignition system

> ON – ON position turns on the entire electrical system including the ignition system

> START – This position energizes the starter solenoid circuit to crank the engine. This position is spring loaded to return to the ON position when is released automatically

• Ignition control module

Ignition control module is an electronic switch that turns the ignition coil's primary current either ON or OFF. Control unit performs the same operation as that of contact points in conventional type of ignition system. It is a network of transistors, capacitors and other electronic parts contained in a plastic case. Control module can be located on the side of the distributor or inside distributor under the dash board. Control module manages the dwell period on its own.

• Ignition coil

Ignition coil produces high voltage required to make current pass in the gap at spark plugs. Ignition is pulse type transformer capable of producing a short fire of high voltage for beginning combustion. It is composed of two sets of windings namely primary winding (outer winding) and secondary winding (inner winding). Secondary winding are wound in opposite direction of primary winding and the ends are attached to primary windings and high voltage terminals.

• Ignition distributor

Distributor controls the ON/OFF cycles of current flow from the primary windings of coil. It makes spark to occur at each spark plug and distributes high voltage to the spark plug. Depending on the load, distributor changes the spark timing. In some electronic ignition systems it also houses ignition coil and switching unit.

• Spark plug

Spark plug is made of porcelain insulator which consists of insulated electrode supported by a metal shell with grounded electrode. They use ignition coil high voltage to ignite the fuel mixture. Spark plug has a simple purpose of supplying a fixed gap along which a high voltage passes through this gap.

Working

When the engine is running, the trigger inside the distributor rotates. As the tooth of trigger wheel passes the pick-up coil, a magnetic field is developed around the pick-up coil. This phenomenon results in the voltage output change in the coil. Then electrical surge is sent to the control unit when trigger wheel pass the pickup coil. The control unit increases electrical surge into cycles of ON/OFF for ignition coil. If the control unit is ON, current passes through primary windings of ignition coil and develops a magnetic field. When the trigger wheel and pickup coil turn OFF the control unit and the magnetic field inside the ignition coil collapses and fires the spark plug.

Electronic ignition system improves fire rate in the system and increases the efficiency of automobile. Nowadays, almost all automobiles are equipped with electronic ignition system.

Airtex Fuel Delivery Systems is the leading aftermarket supplier of mechanical and electric a href=http://www.airtexproducts.comfuel pumps.