Automotive Engine Components Design Questions and Answers – IC Engine – Centre Crankshaft at Angle of Maximum Torque

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This set of Automotive Engine Components Design Questions and Answers for Freshers focuses on “IC Engine – Centre Crankshaft at Angle of Maximum Torque”

1. The maximum torque is due to which component of force on the crank pin?
a) Perpendicular
b) Parallel
c) Concentric
d) Tangential
View Answer

Answer: d
Explanation: The torque is maximum when the tangential component of force on the crank pin is maximum. The force is produced due to the connecting rod.
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2. What is the crank angle from the TDC position for the petrol engine?
a) 30° to 40°
b) 35° to 45°
c) 25° to 35°
d) 20° to 30°
View Answer

Answer: c
Explanation:The crank angle from the TDC position for the petrol engine is 25° to 35° and the crank angle from the TDC position for the diesel engine is 30° to 40°.

3. What is the crank angle from the TDC position for diesel engines?
a) 35° to 45°
b) 25° to 35°
c) 30° to 40°
d) 20° to 30°
View Answer

Answer: c
Explanation: The crank angle from the TDC position for the petrol engine is 25° to 35° and the crank angle from the TDC position for the diesel engine is 30° to 40°.
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4. The relationship between Φ and θ is given by?
a) SinΦ=\(\frac{sin\theta}{L/r}\)
b) CosΦ=\(\frac{sin\theta}{L/r}\)
c) SinΦ=\(\frac{sin\theta}{L\times r}\)
d) CosΦ=\(\frac{cos\theta}{L/r}\)
View Answer

Answer: a
Explanation: The relationship between Φ and θ is given by SinΦ=\(\frac{sin\theta}{L/r}\) where L is the length of the connecting rod and r is the radius of the crank.

5. In the formula SinΦ=\(\frac{sin\theta}{L/r}\), what is L?
a) Lateral shift
b) Length of connecting rod
c) Linear bending
d) Length of stroke
View Answer

Answer: b
Explanation: The relationship between Ф and ϴ is given by SinΦ=\(\frac{sin\theta}{L/r}\) where L is the length of the connecting rod and r is the radius of the crank.
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6. In the formula Pt=PqSin(θ+Φ), what is Pt?
a) The pressure at crankpin
b) The lateral component at crankpin
c) The tangential component at crankpin
d) Power at crankpin
View Answer

Answer: c
Explanation: In the formula Pt=PqSin(θ+Φ), Pt is the tangential component of Pq at the crankpin and Pr is the radial component of Pq at the crank pin.

7. In the formula Pr=PqSin(θ+Φ), what is Pr?
a) The radial component at crankpin
b) Pressure component at crankpin
c) The tangential component at crankpin
d) Vector component at crankpin
View Answer

Answer: a
Explanation: In the formula Pr=PqSin(θ+Φ), Pt is the tangential component of Pq at the crankpin and Pr is the radial component of Pq at the crank pin.
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8. Which are the two forces experienced by the crank pin?
a) Bending and shear moment
b) Two couple force
c) Force and torsional moment
d) Bending and torsional moment
View Answer

Answer: d
Explanation: Bending and torsional moment are the two forces experienced by the crankpin and these forces are produced by bearing 1,2 and 3.

9. In the formula Mt=Pt×r, what is Mt?
a) Couple
b) Bending moment
c) Torsional moment
d) Shear moment
View Answer

Answer: c
Explanation: In the formula Mt=Pt×r, Mt is the torsional moment due to tangential component Pt and r is the crank radius. Hence, the torsional moment is the right answer.
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10. The right-hand crank web is subjected to which stress due to radial component.
a) Tensile
b) Compressive
c) Normal strain
d) Linear stress
View Answer

Answer: b
Explanation: The right-hand crank web is subjected to compressive stress due to the radial component and bending moment in the vertical plane due to forces in the vertical plane.

11. The maximum compressive stress should be less than which stress?
a) Allowable tensile stress
b) Allowable compressive stress
c) Allowable shear stress
d) Allowable bending moment
View Answer

Answer: b
Explanation: The maximum compressive stress should be less than allowable compressive stress if not the crankshaft tends to bend and wobbling takes place.

12. Calculate the width of the crank web when the diameter of crankpin is 65mm?
a) 57.3mm
b) 74.1mm
c) 63.7mm
d) 80.6mm
View Answer

Answer: b
Explanation: w=1.14dc
=1.14×65
=74.1mm

13. Calculate the direct compressive stress when the reaction force is 15340N and the thickness and width of the crank web are 46mm and 75mm?
a) 8.43N/mm2
b) 4.44N/mm2
c) 5.54N/mm2
d) 3.68N/mm2
View Answer

Answer: b
Explanation: σc=\(\frac{(R_1)_v}{W_t}\)
\(\frac{15340}{46\times 75}\)

=4.44N/mm2

14. In the formula σc=\(\frac{(R_1)_v}{W_t}\) , what is (R1)v ?
a) Point load
b) Eccentric load
c) UVL
d) UDL
View Answer

Answer: b
Explanation: In the formula σc=\frac{(R_1)_v}{W_t}[/latex], (R1)v is the eccentric load, w is the width of the crank web and t is the thickness of the crank web.

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

To practice all areas of Automotive Engine Components Design for Freshers, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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