Automotive Engine Components Design Multiple Choice Questions on “IC Engine – Bore and Length of Cylinder”.
1. Piston diameter can be considered as the cylinder bore diameter.
a) True
b) False
Answer: a
Clarification: Piston and Cylinder liner are held very close together such that the clearance between them can be neglected. So, the piston diameter can be considered as the cylinder bore diameter.
2. Where is Indicated power generated?
a) In the crankshaft
b) In the alternator
c) Inside the engine cylinder
d) In the Fuel pump
Answer: c
Clarification: Indicated power is obtained inside the engine cylinder, whereas brake power is obtained in the crankshaft, Alternator and fuel pump absorbs the brake power.
3. The tachometer is used to measure the Indicated power.
a) True
b) False
Answer: b
Clarification: First and foremost, indicated power can’t be measured practically using any device. Hence, Tachometer can’t be used to measure the indicated power.
4. In an engine running at 2200RPM has BP=35KW and FP=3KW, what is the value of IP?
a) 38KW
b) 38MW
c) 32KW
d) 32MW
Answer: a
Clarification: IP=BP+FP
IP=35KW+3KW
=38KW
5. An engine has a mechanical efficiency of 80% with an IP of 35KW, calculate BP.
a) 28MW
b) 2.8W
c) 2.8GW
d) 28KW
Answer: d
Clarification: ηmechanical=(frac{BP}{IP})
BP=(0.8×35)
=28KW
6. In the formula IP=(frac{plAn}{60}), what does ‘n’ represent?
a) RPM of the engine
b) Number of working strokes
c) Area of cylinder
d) Pressure
Answer: b
Clarification: ‘n’ represents the number of working strokes, RPM is denoted by ‘N’, Area is denoted by ‘A’ and pressure is denoted by ‘Pm’.
7. What is the Standard unit of Pm?
a) N/m3
b) N/mm2
c) KN/mm2
d) KN/m3
Answer: b
Clarification: Pm is called as mean effective pressure, the pressure is a force upon the unit area(N/mm2). K is not a unit; it is a multiplier.
8. A 2-stroke engine has following specifications A=9852.3mm2, IP=4600, Pm=0.35Mpa, N=500RPM. Calculate the value of length.
a) 80mm
b) 80m
c) 0.8mm
d) 8m
Answer: a
Clarification: IP=(frac{plAn}{60})
4600=(0.35×l×9852.3×1000)/60
l=80mm
9. What is the standard unit of BP?
a) KW
b) W
c) MW
d) N/mm2
Answer: b
Clarification: BP is called Brake Power and the standard unit of power is Watt represented by ‘W’. K and M are just Multipliers and N/mm2 is the unit for pressure.
10. In the formula IP=(frac{plan}{60}), In what scale l(length) has to be considered?
a) mm
b) Km
c) m
d) µm
Answer: c
Clarification: Here length is always considered in meters as a standard, whereas diameter is taken in mm, during the early age of engines the stroke length was more when compared to bore diameter, µm gives value in 1000s and Km gives value in 0.0001, so the conventional unit meters.
11. Which of the below-mentioned test is used to find FP?
a) Calorimeter test
b) FIP test
c) Compression test
d) Morse test
Answer: d
Clarification: FP cannot be measured practically, by performing more test i.e., short-circuiting the spark plug or the fuel supply and by calculation, FP can be calculated theoretically.
12. What is Frictional Power?
a) It is the power loss due to friction
b) It is the power generated by friction
c) It is the power generated by crankshaft bearings
d) It is the friction generated due to power
Answer: a
Clarification: Engine is not 100% efficient, there is a power loss due to friction between the piston and the cylinder. Therefore, Frictional Power is the power loss due to friction.