This set of Automotive Engine Auxiliary Systems Multiple Choice Questions & Answers (MCQs) focuses on “Fuel Injection Pump”.
1. Which of the following helps in the fuel distribution in a distributor type fuel injection pump?
b) Rocker arms
Explanation: In a distributor type of fuel injection pump the fuel is distributed to each cylinder using a rotor. The rotor has a central longitudinal passage and set of radial holes which depends on the engine configuration.
2. To which of the following the number of radial holes equal in a distributor type fuel injection pump?
a) To the float valve
b) To the number of the engine cylinder
c) To the number of gears
d) To the number of governors
Explanation: In a distributor type fuel injection pump there is a set of radial holes (suction port) equal to the number of the engine cylinder. Similarly, the outer sleeve also has a set of an equal number of holes (delivery ports ) which are offset from the suction ports.
3. How is the fuel injection time controlled in a distributor type fuel injection pump?
a) Internal-cam ring
Explanation: The fuel injection timing in a distributor type of fuel injection pump is controlled by rotating the internal-cam ring. As the engine speed increases, the fuel feed pump delivery pressure increases.
4. Which of the following is moved to a position so that the excess fuel can be supplied during cold start conditions?
b) Spark plug
c) Control rack
Explanation: For starting the engine from cold, more fuel is required to be injected which is done by moving the control rack to a position where the excess fuel is delivered by the pump. The rack has to be brought to a normal position immediately after the engine starts.
5. Which of the following type part is not used in jerk type fuel injection pump?
b) Delivery valve
c) Control sleeve
Explanation: The main parts of a jerk type fuel injection pump are the delivery valve, the plunger, the control sleeve, and the control rack. Where the delivery valve is spring-loaded. Whereas the rotor is absent in this type of injection pump.
6. Which of the decreases when the plunger is given an anticlockwise rotation?
a) Compressed air
c) Coolant supply
d) Lubricating oil
Explanation: When the plunger rotates in the anticlockwise direction the fuel injection per stroke decreases whereas when a clockwise rotation will delay the end of delivery, increasing the effective plunger stroke and consequently the fuel supply injected.
7. Which of the following material is used in the fabrication of pump housing?
a) Aluminum alloy
b) Cast iron
Explanation: The material used in the fabrication of pump housing is either a single aluminum alloy casting or aluminum alloy cam box is bolted on to a pumping head of steel and the governor housing is an extension of the cam box.
8. How many degrees of advancement is provided by injection timer?
Explanation: The timing of injection will be required to be advanced with an increase in engine speed. This advancement is done by injection timer which provides a maximum of 8 degrees of Advance. The timer is mounted on the front end of the injection pump and works on the principle of centrifugal force.
9. Which type of shape is provided on the plunger so that the quantity of fuel injected can be controlled?
Explanation: The plunged contains a helix at its upper end which serves to control the quantity of fuel to be injected. As the helix uncovers the spill port, the fuel escapes through the vertical slot in the plunger and spill port and pressure are released, shutting the valve down on its seat.
10. Which among the following is not a part of the pump housing?
b) Pumping head
Explanation: The pump housing is the main housing that contains cambox (which supports camshaft tappet assemblies, control mechanism, and governor ) and the pumping head which is made of single aluminum alloy whereas the alternator has no role in the pump housing.
11. Which of the following increases concerning the metering valve when the accelerator pedal is pressed?
Explanation: A metering valve controlled by the governor regulates the amount of fuel entering the rotor. Pressing the accelerator pedal increases the area of the metering port allowing more fuel to enter the rotor, thereby increasing the engine speed.
12. How many weights are connected between the input and the output sides of the timer?
Explanation: Two centrifugal weights connect the input and output sides of the timer. When the speed increases, the weights fly apart causing the output segment plates and thereby the camshaft of the fuel injection pump to turn in the direction of rotation.
13. Which of the following is not a function of the fuel injection pump?
a) Deliver accurately
b) High pressure
c) Correct sequence
Explanation: The function of a fuel injection pump is to deliver accurately, the metered quantity of fuel under high pressure, at the correct instant and in the correct sequence, to the injector fitted on each engine cylinder.
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