Subject: Automobile Engineering

Topic: Electrical System, Starting Systems & Alternator

Difficulty: Medium

Distributorless ignition system (DIS) is the ignition system in which the distributor of electronic ignition system is replaced with number of induction coils ie one coil per cylinder or one coil for pair of cylinder, & the timing of the spark is controlled by ignition control unit (ICU) &.engine control unit (ECU), which makes this system more efficient & accurate. Due to the use of multiple ignition coils which provides direct voltage to the spark plugs this system is also known as Direct ignition system.
Working:
i) When the ignition switch is turned ON, the current from the battery starts to flow through the ignition switch to the Electric Control Unit of the vehicle which is connected to the ignition module & coils assembly.

ii) The triggering wheel mounted on the camshaft & the crankshaft have spaced teeths with one gap & the position sensors which consists of the magneticcoil that constantly generates magnetic foield as the camshaft & the crankshaft rotates.
iii) When these gaps come infront of the positioning sensors fluctuation in the magnetic field occurs & the signals of both the sensors are sent to the ignition module which inturn senses are sent to the ignition module which inturn senses the signals & the current steps to flow in the primary winding of the coils & when these gaps get away from the sensors the signals of both the sensors are sent to the ignition module which turns ON the current to flow in the primary winding of the coils.
iv) Thus continues makes & breaks of the signals generate magnetic field in the coils which in turn induced EMF in the secondary winding of the coils & increase the voltage upto 10,000 volts.
v) This high voltage is then sent to spark plug & generation of sparks takes place.
vi) The timing of spark plug is controlled by electronic control unit by continuously processing the data.received from ignition control module.