# Automotive Engine Components Design Questions and Answers – IC Engine – Piston Ribs and Cups

This set of Automotive Engine Components Design Multiple Choice Questions & Answers (MCQs) focuses on “IC Engine – Piston Ribs and Cups”.

1. Why piston ribs are provided in the piston?
a) To strengthen cylinder
c) To strengthen cams
d) To strengthen crankshaft

Explanation: Ribs strengthen the piston head against the gas pressure. They increase the rigidity and prevent the distortion of the piston head.

2. Ribs transmit heat from ______ to piston rings.
b) skirt portion
c) rings
d) piston pin

Explanation: Ribs transmit a large portion of combustion heat from the piston head to the piston rings. This reduces the temperature difference between the center and side of the piston head.

3. The side thrust is created by which component of the engine?
a) Camshaft
b) Crankshaft
c) Connecting rod
d) Wrist pin

Explanation: The side thrust is created by the obliquity of the connecting rod and it is transmitted to the piston at piston pin. Hence, connecting rod is the right answer.

4. The side thrust is transmitted to the cylinder wall through which portion of the piston?
b) skirt portion
c) rings
d) piston pin

Explanation: The side thrust is due to the ovality of the piston, due to the gas pressure on the piston head side thrust is created and it is transmitted to the cylinder wall through the skirt portion.

5. Find the range of thickness of the ribs when the thickness of the piston head is 8mm?
a) 2 to 4mm
b) 3.5 to 4.5mm
c) 2.6 to 4mm
d) 3.6 to 4mm

Explanation: Thickness of ribs is given by tr=$$\frac{t_h}{3}to\frac{t_h}{2}$$
=$$\frac{8}{3}to\frac{8}{3}$$
= 2.6 to 4mm
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6. Find the radius of the cup, when the bore diameter is 150mm?
a) 100mm
b) 110mm
c) 115mm
d) 105mm

= 0.7×150
= 105mm

7. The additional space provided on the piston head is also known as______
a) cup
b) cone
c) cube
d) sphere

Explanation: The additional space provided on the piston head is known as a cup. The space for the cup on the piston head is decided based on the volume of combustion.

8. When the thickness of the piston head is 5mm, the thickness of the ribs is 1.6 to 2.5mm.
a) True
b) False

Explanation: When the thickness of the piston head is less than 6mm, ribs are not required hence the answer, thickness of ribs 1.6 to 2.5mm is wrong.

Sanfoundry Global Education & Learning Series – Automotive Engine Components Design.