Automotive Engine Components Design Multiple Choice Questions on “IC Engine – Piston Barrel”.
1. Where can we see the piston barrel in the piston?
a) Above the piston head
b) Below piston ring
c) Below the wrist pin
d) Below the piston head
Answer: d
Clarification: Piston barrel is the cylindrical portion of the piston below the piston head. It is the inner cavity below the piston head to the open end of the piston.
2. Which of the mentioned below is the formula for calculating the thickness of the piston barrel at the top end?
a) t4=(0.03D+b+4.9)
b) t4=0.03D+b+6.9)
c) t3=(0.03D+b+4.9)
d) t3=0.03D+t4+4.9)
Answer: c
Clarification: The thickness of the piston barrel at the top end is given by t3=(0.03D+b+4.9) where D is the piston diameter and b is the radial width of the ring.
3. In the formula t3=(0.03D+b+4.9) what is the unit of b?
a) m
b) μm
c) mm
d) mm2
Answer: c
Clarification: This is the formula of the thickness of the piston barrel at the top end, where D is the piston diameter and b is the radial width of the ring. Since it is width so the standard is mm.
4. Calculate the thickness of the piston barrel at the top end, when D=80mm and b=7.5mm?
a) 14.8mm
b) 15.6mm
c) 13.7mm
d) 16.6mm
Answer: a
Clarification: t3=(0.03D+b+4.9)
= (0.03×80+7.5+4.9)
= 14.8mm
5. Calculate the thickness of the piston barrel at the lower end when t3=13mm?
a) 4.5 to 5mm
b) 3.25 to 4.55mm
c) 5.6 to 7mm
d) 2.25 to 4.6mm
Answer: b
Clarification: t4 = (0.25t3 to 0.35t3)
= (0.25×13) to (0.35×13)
= 3.25 to 4.55mm
6. Which type of piston rings are preferred in an engine?
a) Oversized rings
b) Undersized rings
c) Thin rings
d) Thick rings
Answer: c
Clarification: Thin rings reduce the frictional losses and wear of the surface. Several thin rings have better sealing action than a few thick rings.
7. What is the gap between the free ends of the ring before assembly when b=6mm?
a) 21 to 24mm
b) 20 to 23mm
c) 22 to 23mm
d) 21 to 25mm
Answer: a
Clarification: G=3.5b to 4b
= 3.5×6 to 4×6
= 21 to 24mm
8. What is the gap between the free ends of the ring after assembly when D=80mm?
a) 0.7 to 0.43mm
b) 0.11 to 0.25mm
c) 0.1 to 1.9mm
d) 0.16 to 0.32mm
Answer: d
Clarification: G=0.002D to 0.004D
= 0.002×80 to 0.004×80
= 0.16 to 0.32mm
9. Calculate the distance from the top of the piston to the first ring grove when th=7mm?
a) 8.5 to 10mm
b) 7.5 to 9mm
c) 7 to 8.4mm
d) 8 to 9.4mm
Answer: c
Clarification: h1=th to 1.2th
= 7 to 1.2×7
= 7 to 8.4mm
10. Calculate the width of the ring groove when h=5mm?
a) 3 to 5.8mm
b) 3.75 to 5mm
c) 4 to 5.9mm
d) 4.7 to 5.2mm
Answer: b
Clarification: h2=0.75h to h
=0.75×5 to 5
= 3.75 to 5mm