(a) Suction Type Electric Fuel Pump
(b) Pusher Type Electric Fuel Pump (a) Suction Type Electric Fuel Pump Suction type fuel pump electrically work functions upon similar principle of pulling and pushing effect of a diaphragm. The only dissimilarity being that in this kind pump, tip and down movement of the diaphragm affect electrically while a mechanical fuel pump, this faction is through mechanical means.
The major parts of suction type electrical fuel pump as below:
(i) Lower major body containing bellows or diaphragms link contact breaker, solenoid and cover.
(ii) Upper body contains inlet and outlet check valves.
(iii) Sediment howl and strainer.
Metal bellows or diaphragm is function with a solenoid. As ignition is switched on, current run as of the battery to windings of solenoid and armature is pull down which results in extend of bellows or down movement of diaphragm. This creates suction or vacuum in major chamber due to which fuel is drawn into main chamber during inlet valve. As armature reach its lower limit of travel, contact points are separated off which cut off electrical trip. The go back spring then pushes armature up and the bellows are contracted or diaphragm moves up. These results in pumping of fuel pump major chamber through outlet valve. As armatures reach upper limit of its move, it closes the contact points with the solenoid is again energised to pull down armature over. This carry on make and break moving the movement of bellows or diaphragm is constant as long as ignition switch is on. (b) Pusher Type Electric Fuel Pump The working of a pusher type electrical fuel pump is as follows: While the ignition is switched on the electric current flows in solenoid generate magnetic field. This magnetic field pulls armature down along by diaphragm as it is attached by it, with this partial vacuum is formed over the diaphragm, which opens the contact point therefore current supply is interrupted, by this magnetic field diminish, armature along by diaphragm gets lifted up to pressure of spring below diaphragm, put pressure on petrol in chamber over diaphragm, which closes inlet valve and opens outlet valve during which petrol gets pumped to carburettor. If petrol is not necessary with carburetor, in this case diaphragm remains pressed down by contact point open not allow current to how to solenoid.