250+ TOP MCQs on IC Engine – Piston Pin and Answers

Automotive Engine Components Design Multiple Choice Questions on “IC Engine – Piston Pin”.

1. What is the function of the piston pin?
a) To connect the piston to the crankshaft
b) To connect the piston to the piston head
c) To connect cam to the piston
d) To connect the piston to the connecting rod
Answer: d
Clarification: The major function of the piston pin is to connect the piston to the connecting rod. The piston pin is also called a gudgeon pin or wrist pin.

2. Piston pin is having which cross-section?
a) Hollow rectangular
b) Solid circular
c) Hollow circular
d) Solid rectangular
Answer: c
Clarification: Piston pin is made of the hollow circular cross-section to reduce its weight. However, the strength of solid circular-section is equal to a hollow circular cross-section.

3. Piston pin passes through which part of the piston?
a) Oil ring
b) Riffle hole
c) Piston bosses
d) Compression ring
Answer: c
Clarification: Piston pin passes through the piston bosses provided on the inner side of the piston skirt and a bearing bush inside the small end of a connecting rod.

4. The end movement of the piston pin is restricted by which component?
a) Circlip
b) Welding
c) Bolting
d) Riveting
Answer: a
Clarification: The end movement of the piston pin is restricted by the means of the circlip, circlip is a thin circular wire that is connected on both the side of the piston pin.

5. Calculate the resisting force when (P_b)_l=5N/mm², d₀=110mm, l₁=67?
a) 73426N
b) 36850N
c) 238746N
d) 28642N
Answer: b
Clarification: Resisting force=(P_b)_ld₀l₁
= 5×110×67
= 36850N

6. What is the formula to calculate resisting force?
a) Resisting force=(P_max)_ld₀l₁
b) Resisting force=(P_b)_ld_il₁
c) Resisting force=(P_b)_ld₀l₁
d) Resisting force=(P_b)_ld₀l_s
Answer: c
Clarification: The formula to calculate Resisting force is (P_b)_ld₀l₁where (P_b)_l is the bearing pressure at the bush, d₀ is the outer diameter and l₁ is the length of the piston pin.

7. Calculate the inner diameter of the piston when the outer diameter is 50mm?
a) 30mm
b) 25mm
c) 40mm
d) 35mm
Answer: a
Clarification: Inner diameter d_i=0.6×d₀
= 0.6×50
= 30mm

8. Calculate the mean diameter of the piston boss for grey cast iron piston, when d_o=50mm?
a) 30mm
b) 50mm
c) 60mm
d) 70mm
Answer: d
Clarification: Mean diameter of piston bosses d_i=1.4×d₀
= 1.4×50
= 70mm

9. Calculate the mean diameter of the piston boss for aluminum alloy piston, when d_o=50mm?
a) 60mm
b) 70mm
c) 80mm
d) 90mm
Answer: c
Clarification: Mean diameter of piston bosses d_i=1.6×d₀
= 1.6×50
= 80mm

10. The small gap between the cylinder liner and piston is known as _____
a) piston rib
b) piston clearance
c) piston head
d) wrist clearance
Answer: b
Clarification: Piston clearance is the clearance between the cylinder liner and piston that is provided to take care of thermal expansion and distortion under load.