Internal Combustion Engine

Internal Combustion Engine

1. For each crankshaft revolution, the cam shaft revolves (a) one-half turn (b) two turns (c) four turns (d) as many turns as the number of valves in the engine Ans : (a) 2. What is the material of connecting rod? (a) mild steel (b) forged steel (c) tool steel (d) cast iron Ans : (b) 3. Stroke of engine is : (a) volume of the cylinder (b) length of the connecting rod (c) internal dia of cylinder (d) distance between TDC and BDC Ans : (d) 4. A certain engine produces 10 kw indicated power. Its mechanical efficiency is 70%. Then the frictional power is– (a) 2 kw                  (b) 2.5 kw (c) 3 kw                 (d) 3.5 kw Ans : (c) 5. Morse test is applicable only for– (a) Single cylinder SI engines (b) Single cylinder CI engines (c) Multi-cylinder CI engines (d) Multi-cylinder SI and CI engines Ans : (d) 6. Petrol and diesel engines of automobile are : (a) Rotary engine (b) Reciprocating engine (c) External combustion engine (d) Carnot heat engine/ Ans : (b) 7. A cyclic device which produces work continuously at the expense of heat input is known as : (a) Refrigerator             (b) Heat tump (c) Heat engine             (d) Throttling Ans : (c) 8. The component of the engine that connects the link between the small end of the connecting rod and the piston is known as : (a) Cams (b) fly wheel (c) Gudgean pin (d) Piston ring Ans : (c) 9. To connect piston to the connecting rod the...are used. (a) rod caps (b) cap bolts (c) small end bearing (d) gudgeon pins Ans : (d) 10. The best firing order for a six cylinder in-line engine is : (a) 1 2 3 4 5 6                (b) 2 3 4 5 6 1 (c) 1 4 2 6 3 5                (d) 1 5 3 6 2 4

Ans : (d)

11. Which one of the following item is made of aluminium alloy? (a) piston ring (b) Connecting rod (c) piston (d) crankshaft

Ans : (c)
12. For the same rated power and same engine
speed of a two stroke engine and a four stroke
engine. Which of the following statement is
correct
(a) Heavier flywheel is required for two stroke
engine
(b) Heavier flywheel is required for four stroke
engine
(c) Mass of the flywheel should be same for both
the engines
(d) Mass of the flywheel depends upon the load
on the engine
Ans. (b)
13. Which of the following factors contribute
towards detonation in an engine?
(a) Engine overheating
(b) High compression ration
(c) Lean fuel mixture
(d) All option are correct
Ans : (d)
14. The working cycle in case of four stroke engine
is completed in .......... number of revolution of
crankshaft?
(a) Half                        (b) 1
(c) 2                             (d) 4

Ans : (c)
15. If the temperature of intake air in an I.C.
engine is lowered, its efficiency will
(a) increase
(b) decrease

(c) remains unchanged
(d) will increase upto certain limit and then
decrease
Ans : (a)

16. Increasing the compression ratio beyond a certain limit, results to .......... (a) delay in fuel burning (b) engine knocking (c) excessive heat in the engine (d) high fuel consumption Ans : (b) 17. The fuel air ratio in a petrol engine fitted with suction carburetor, operating with dirty air filter as compared to clean filter will be (a) higher (b) lower (c) remain unaffected (d) unpredictable Ans : (d) 18. How is the thermal efficiency of an IC engine related to compression ratio? (a) Increase (b) Decrease (c) May increase or decrease (d) Remains same Ans : (a) 19. All the processes in an air standard cycle are assumed to be_____ (a) adiabatic (b) irreversible (c) isothermal (d) reversible Ans : (d) 20. For the same operating maximum pressure and temperature, which cycle will have the highest efficiency? (a) Diesel cycle (b) Dual cycle (c) Otto cycle (d) None of these Ans : (a)

21. The accumulation of carbon in a cylinder
results in increase of
(a) clearance volume
(b) volumetric efficiency
(c) ignition time
(d) effective compression ratio
Ans : (d)
22. Which of the following factors does NOT
contribute towards detonation in an engine?
(a) Engine overtheating
(b) High compression ratio
(c) Stoichiometric fuel mixture
(d) Wrong spark plug
Ans : (c)
23. Which of the following sequence is TRUE for
same compression ratio and added heat?

Ans : (b)
24. Which of the following cannot be classified as
an internal combustion engine?
(a) Diesel engine
(b) Petrol engine
(c) Gas turbine
(d) Steam turbine
Ans : (d)
25. Piston rings usually made of :
(a) Carbon steel
(b) Aluminium
(c) Cast-iron
Ans : (c)
26. The two stroke cycle engine has :–
(a) one suction valve and one exhaust valve
operated by one cam

(b) one suction valve and one exhaust valve operated by two cams (c) only ports covered and uncovered by piston to effect charging and exhausting (d) None of the above

Ans : (c)

27. With increasing temperature of intake air, I.C. engine efficiency: (a) Decreases (b) Remains same (c) Increases (d) Depends on other factor Ans : (a)

28. For same compression ratio (a) Thermal efficiency of ottocycle is greater than that of diesel cycle (b) Thermal efficiency of ottocycle is less than that of diesel cycle (c) Both (a) & (b) (d) Thermal efficiency of ottocycle is equal to that of diesel cycle Ans : (a)

29. One horse power is equal to

(a) 102 Watts (b) 75 Watts
(c) 550 Watts (d) 735 Watts

Ans : (d)

30. The firing order for a six cylinder engine is:

(a) 1-6-2-5-3-4 (b) 1-5-3-6-2-4
(c) 1-2-5-4-3-6 (d) 1-3-2-6-5-4
Ans : (b)