MCQ Question on Design of I. C. Engine components

 

Topic- Design of I. C. Engine components

1. Compression Ratio in diesel engine is lesser than that in Spark Ignition engine.
a) True
b) No
c) They are equal
d) Doesn’t matter
View Answer

Answer: b. No
Explanation: In diesel engine, there is no spark to ignite, charge is compressed to greater extent to support self-ignition.

2. Petrol engine are more economical than diesel engine.
a) True
b) False
View Answer

Answer: b. False
Explanation: Diesel engine have better thermal efficiency and hence are more economical.

3. There are ____ types of liners.
a) 1
b) 2
c) 3
d) 4
View Answer

Answer: b
Explanation: Dry liners and wet liners.

4. If no re boring allowance is to be given, then thickness of cylinder wall is max pressure is 3.5N/mm², bore diameter=200mm and permissible tensile stress is 40N/mm².
a) 7mm
b) 8mm
c) 9mm
d) 10mm
View Answer

Answer: c
Explanation: t=pD/2σ=8.75mm.

5. If diameter of cylinder of bore is 120mm, then thickness of the cylinder will be
a) Information not sufficient
b) 7mm
c) 12mm
d) 6mm
View Answer

Answer: b
Explanation: t=0.045D + 1.6.

6. If diameter of cylinder bore is 120mm, then thickness of dry liner will be
a) 2.2mm
b) 3.6mm
c) 4.8mm
d) 6mm
View Answer

Answer: b
Explanation: t= 0.03D to 0.035D.

7. If diameter of cylinder bore is 120mm, then thickness of water jacket wall will be
a) 4.26mm
b) 5.25mm
c) 2.56mm
d) All of the listed
View Answer

Answer: d
Explanation: p=t/3 to 3t/4, where t= thickness of cylinder wall=7mm.

8. If diameter of cylinder bore is 120mm, then thickness of water cylinder flange will be
a) 8.8mm
b) 10.2mm
c) 7.8mm
d) 12mm
View Answer

Answer: a
Explanation: q=1.2t to 1.4t.

9. If nominal diameter of bolt used is 20mm, then find the radial distance between outer diameter of flange and pitch circle diameter of studs.
a) 24mm
b) 28mm
c) 32mm
d) 36mm
View Answer

Answer: b
Explanation: r=d+6 to 1.5d i.e. 26mm to 30mm.

10. The circumferential hoop stress and longitudinal stress are both shear stress.
a) True
b) False
View Answer

Answer: b
Explanation: They both are tensile stress.

11. The circumferential hoop stress and longitudinal stress act in same direction and hence are straight away added.
a) True
b) False
View Answer

Answer: b
Explanation: They both act perpendicularly to each other and thus net stress in these directions is reduced.

12.  A piston has allowable tensile stress of 50 N/mm² and has bore diameter 150 mm. Considering strength of piston, what will be the thickness of piston head if maximum pressure of 10 N/mm² acts on it?

a. 29 mm
b. 35 mm
c. 53 mm
d. Insufficient data

View Answer

Answer: a. 29 mm

13.  A piston made of gray cast iron has piston head thickness of 20 mm. What will be thickness of piston barrel under piston rings if it has allowable tensile stress of 30 N/mm²? ( Bore diameter = 50 mm & P_max =15 N/mm²)

a. 10 mm
b. 20 mm
c. 30 mm
d. Insufficient data

View Answer

Answer: b. 20 mm

14.  What is the function of gudgeon pin?

a. Acts as stiffeners
b. Supports piston head
c. Connects piston to connecting rod
d. All of the above

View Answer

Answer: c. Connects piston to connecting rod

15. Which of the following parts of piston act as bearing for connecting rod side thrust?  

a. Reinforcing ribs
b. Piston barrel
c. Piston gudgeon
d. Piston skirt

View Answer

Answer: d. Piston skirt

16. Single cylinder four stroke engine has brake power of 8 kW and brake mean effective pressure of 0.55 Mpa. What is the length of cylinder which is 1.2 times of bore diameter? (n = 3000 rpm)

a. 110 mm
b. 103 mm
c. 70 mm
d. 65 mm

View Answer

Answer: b. 103 mm

17. Which stress is induced in cylinder wall due to side thrust of the piston?

a. Axial stress
b. Circumferential stress
c. Longitudinal stress
d. Bending stress

View Answer

Answer: d. Bending stress

18. Thermal stress in cylinder liners can be reduced by _______

a. increasing the wall thickness of cylinder liner
b. increasing velocity of flowing water through jacket
c. both a. and b.
d. none of the above

View Answer

Answer: a. increasing velocity of flowing water through jacket

19. Which of the following materials are used for cylinder liners?

a. Alloy cast iron
b. Grey cast iron
c. Both a. and b.
d. None of the above

 View Answer

Answer: c. Both a. and b.

20.  Which type of cylinder liners are used in engines having bore diameter more than 125 mm?

a. Dry liners
b. Wet liners
c. Both a. and b.
d. None of the above

View Answer

 Answer: b. Wet liners

21. Which of the following statements is/are false if separate cylinder liner is pressed inside the cylinder of large engines?

a. Easy replacement of liner in case of wear and tear
b. Cheap grade material cannot be used for jacket
c. Liner is to be made of heat resistant cast iron
d. None of the above

View Answer

Answer: b. Cheap grade material cannot be used for jacket