250+ TOP MCQs on Petrol Engine Fuel Supply System – Fuel Pumps and Answers

Automotive Engine Auxiliary Systems online quiz on “Petrol Engine Fuel Supply System – Fuel Pumps”.

1. Which material is used for the valves of the A.C mechanical pump?
a) Cast iron
b) Plastic
c) Bakelite
d) Paper
Answer: c
Clarification: The A.C pump’s valves are made up of Bakelite, which being lighter keeps the inertia stresses minimum and they are resistant to heat, scratches, and destructive solvents which makes it be most commonly used.

2. What is the pressure range in kPa in the petrol pipeline between the fuel pump and the carburetor?
a) 5-10
b) 10-20
c) 20-35
d) 35-40
Answer: c
Clarification: The pressure in the petrol pipeline between the fuel pump and the carburetor, is kept under the pressure between about 20 and 35kPa, the exact pressure range being determined by the stiffness of the diaphragm return spring.

3. Which of the following provides the force to drive the pump?
a) Crankshaft
b) Differential
c) Camshaft
d) V-belt
Answer: c
Clarification: The driving force the pump is taken from camshaft by the means of eccentric or cam. The eccentric cam operates the rocker arm which is in conjunction with the diaphragm return spring pushes the diaphragm up and down.

4. Which of the following helps in the relief of the excess pressure which is built up?
a) Pull rod
b) Diaphragm return spring
c) Camshaft
d) Suction valve
Answer: b
Clarification: The pump will build up excessive pressure which may damage the pump itself. This is taken care of by the diaphragm return spring which remains partially or fully compressed depending upon the line pressure.

5. Which material is used in the diaphragm of an A.C mechanical pump?.
a) Paper
b) Metal sheet
c) High-grade cotton and rubber
d) Ceramic
Answer: c
Clarification: The diaphragm used in the A.C mechanical pump is made out of high-grade cotton impregnated with synthetic rubber. The downward movement of the diaphragm causes a vacuum in the chamber which causes the inlet valve to open.

6. Which type of energy is used to operate the diaphragm in an S U electrical pump?
a) Mechanical
b) Hydraulic
c) Electrical
d) Solar
Answer: c
Clarification: Alternate vacuum and pressure are produced due to movement of the diaphragm which is caused electrically in the S U electrical pump. Closing the ignition switch energies the solenoid winding, magnetic flux is generated which pulls the armature to which diaphragm is attached.

7. Which of the following is the correct sequence of fuel travel?
a) Tank -fuel pump- fuel filter -carburetor
b) Tank -fuel filter- fuel pump -carburetor
c) Fuel filter -fuel pump- tank-carburetor
d) Carburetor-fuel pump- fuel filter-tank
Answer: a
Clarification: The fuel flows from the fuel tank to the fuel pump where the fuel is pumped to high pressure and then the high-pressure fuel enters the filter and the dust and retained in the filtered and then the fuel is sent into the carburetor.

8. Which valve opens when the downward movement of the diaphragm causes a vacuum in the chamber?
a) Outlet
b) Inlet
c) Both outlet and inlet
d) Transfer
Answer: b
Clarification: The Downward movement of the diaphragm causes a vacuum in the chamber which causes the inlet valve to open. This vacuum helps in the suction of the oil and is one of the most important processes in pump operation.

9. Which system experiences Vapour locking in the fuel system?
a) A.C mechanical pump
b) S U electrical pump
c) Both a and b
d) Electrical pump
Answer: a
Clarification: Since the A-C pump is situated close to the engine due to which they are exposed to engine heat, which may result in vapor locking in the fuel system. Which is taken care of by the diaphragm return spring.

10. Which of the following component movement interrupts the electrical supply by disconnecting the breaker points?
a) Float chamber
b) Diaphragm
c) Strainer
d) Armature
Answer: d
Clarification: The armature moves, it interrupts the electric supply by disconnecting the breaker points. Due to which the solenoid is de-energized and the armature falls back, causing the diaphragm to move to create pressure in the pump chamber.

11. Which of the following has the requirement of placing the pump necessarily close to the engine ?
a) A.C mechanical pump
b) S U electrical pump
c) Both a and b
d) Electric pump
Answer: a
Clarification: The pump need notbe situated close to the engine in S U electrical pump therefore in the A.C mechanical type the pump needs to be situated close to the engine thus they are subjected to engine heat.

12. In which system the pump starts to operate immediately as the ignition is switched on?
a) A.C mechanical pump
b) S U electrical pump
c) Both
d) Mechanical pump
Answer: b
Clarification: In an S U electrical pump the electric pump needs not to wait for the engine to start. It starts to operate immediately as the ignition is switched on. Whereas the A-C mechanical pump does not have this advantage.

13. Which property of the diaphragm return spring helps in the determination of the exact pressure range?
a) Tension
b) Stress
c) Starin
d) Stiffness
Answer: d
Clarification: The exact pressure range being determined by the stiffness of the diaphragm return spring. The controlled pressure in the petrol supply line is very important to be maintained. If the pressure is low, the petrol supply will not be able to keep pace with the demand under high speed or high load conditions.

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