Question 3
-
Fig. 2 is the block diagram of an ignition system.
(a) State the:
(i) name of each part lettered A to F;
(ii) function of each part lettered A to F.
(b) State the function of the system in a motor vehicle.
Observation
The expected answers were;
(a) (i) Name of each part lettered A – F
A – earth/ground
B – battery/cell
C – switch
D – coil
E – distributor
F – plug/spark plug/capacitor/condenser
(ii) Function of each part lettered A – F
A – Completes the circuit of the ignition system.
B – Supplies the current/voltage/power/initial current needed by the system.
C – Put on/connect and off/disconnect the supply from the battery to the coil.
D – Transforms voltage to the value required to produce spark at the plug gap and ignite
the mixture in the combustion chamber/steps up battery voltage.
E – Distributes/channels/share/step-up the current in the system to all the plugs.
F – Ignite the mixture in the combustion chamber/produce spark needed to start the engine.
(b) Function of the ignition system in a motor vehicle
It amplifies the battery voltage and distributes it to the plugs in turns.
It was reported that only a few candidates attempted Question 3 and majority of those who attempted it did not respond well. They showed poor understanding of ignition systems. Teachers are encouraged to emphasize this area of the syllabus during instruction.