250+ TOP MCQs on Injection Timing and Answers

IC Engines Multiple Choice Questions on “Injection Timing”.

1. The fuel is injected into the inlet manifold of each cylinder at _____________ timing.
a) same
b) different
c) unpredictable
d) none of the mentioned
Answer: b
Clarification: The injection of fuel into the inlet manifold of each cylinder is at different timing.

2. The timing at which the injection of the fuel takes place inside the inlet manifold is called _____________ timing.
a) injection
b) suction
c) combustion
d) none of the mentioned
Answer: a
Clarification: Injection timing is defined as the timing at which the injection of the fuel takes place inside the inlet manifold.

3. In _____________ cylinder, the piston moves up from BDC to TDC during the exhaust stroke.
a) one
b) two
c) three
d) four
Answer: a
Clarification: Only in one cylinder, the piston moves up from BDC to TDC during the exhaust stroke and not in two or three cylinder engines.

4. Just before the piston reaches TDC during exhaust stroke, injection of the fuel takes place into the inlet manifold of the cylinder at about 60º crankangle before TDC.
a) True
b) False
Answer: a
Clarification: Yes, just before the piston reaches TDC during exhaust stroke, injection of the fuel takes place into the inlet manifold of the cylinder at about 60º crankangle before TDC.

5. At the beginning of the compression stroke, intake valve opens and the air fuel mixture is sucked into the cylinder during the suction stroke.
a) True
b) False
Answer: b
Clarification: No, but at the beginning of the suction stroke, intake valve opens and the air fuel mixture is sucked into the cylinder during the suction stroke.

6. In the four cylinder engine, the ECU calculates the appropriate injection timing for each cylinder and the air fuel mixture is made available at each suction stroke.
a) True
b) False
Answer: a
Clarification: yes, in the four cylinder engine, the ECU calculates the appropriate injection timing for each cylinder and the air fuel mixture is made available at each suction stroke.

7. In order to meet the operating conditions, the injection valve is kept open for a longer time by ECU.
a) True
b) False
Answer: a
Clarification: Yes, in order to meet the operating conditions, the injection valve is kept open for a longer time by ECU.

8. In a common rail fuel injection system, injection pressure is dependent on engine speed.
a) True
b) False
Answer: b
Clarification: No, but in a common rail fuel injection system, injection pressure is independent of engine speed.