Internal Combustion engines MCQ’s Consist of 100 MCQ’s from section-B final year mechanical engineering. Prepared by:- Nisar Ahmed, Roll # 13-MCE-08
1. Internal combustion engines that have compression ignition are called : a. Gasoline engines. b. Diesel engines. ( correct) c. Steam engines. d. All of the above. 2. Air filtering is achieved for internal combustion engines by passing air through : a. Copper gauze baffles. b. A felt filter. (correct) c. Oil. d. All of the above. 3. At high elevations, engines operating with a supercharger develop : a. More power than engines without a supercharger. (Correct) b. Less power than engines without a supercharger. c. About the same power as engines without a supercharger. d. None of these. 4. The radiator transfers : a. Heat away from the engine. (correct) b. Heat to the engine. c. Water out of the combustion chamber. d. None of these. 5. Electrical power may be supplied to the electrical systems of motors by : a. Batteries. b. External power lines. c. A magneto. d. All of the above. (correct) 6. Look at the drawing.
This engine uses one piston stroke for each single event in the combustion cycle. This is a: a. One-cycle engine. b. Two-cycle engine. c. Four-cycle engine. (correct) d. Eight-cycle engine. 7. Flow of gas into and out of a cylinder is controlled by : a. The crankcase. b. Valves. (correct) c. The head. d. The spark plugs. 8. Look at the drawing.
High-pressure gas expands in this cylinder and: a. Moves the piston upward. b. Moves the piston downward. (correct) c. The piston remains stationary. d. None of these. 9. In an internal combustion engine, combustion takes place in the : a. Piston. b. Cylinder. (correct) c. Crankshaft. d. Connecting rod. 10. When a shaft is driving a pump or compressor, it is: a. Doing work. (correct) b. Converting chemical energy to mechanical energy. c. Transferring heat. d. All of the above. 11. Combustion requires : a. Fuel. b. Oxygen. c. A source of ignition. d. All of the above. (correct)
12. A complete cycle for an internal combustion engine is composed of : a. An intake stroke and an exhaust stroke. b. Intake, compression, and exhaust stroke. c. Intake, power, and exhaust strokes. d. Intake, compression, power, and exhaust strokes. (correct) 13. A fuel for internal combustion engines is : a. Gasoline. b. Natural gas. c. Diesel. d. All of the above. (correct) 14. The electrical system of an engine produces : a. Fuel. b. Oxygen. c. Compression. d. Ignition. (correct) 15. In a two-cycle engine : a. The inlet port is open when the exhaust is closed. (correct) b. The inlet port and exhaust port are opened at the same time. c. The inlet valve is closed during the exhaust stroke. d. All of the above. 16. In order to have proper timing of valve openings and closings in a four-cycle engine, the camshaft rotates : a. At the same speed as the crankshaft. b. At one half the speed of the crankshaft. c. At twice the speed of the crankshaft. d. At four times the speed of the crankshaft. (correct) 17. The source of oxygen for combustion of the fuel in an engine is : a. Pure oxygen. b. Air. (correct) c. Carbon dioxide. d. Nitrogen. 18. Higher than normal water temperature may be caused by : a. An overloaded engine. b. A constriction in the water flow. c. Both of the above. (correct) d. Either A or B. 19. A large industrial internal combustion engine is usually operated by the operator : a. At the instrument panel. (correct) b. At the engine itself. c. Both A and B. d. Neither A nor B.
20. Ignition of the fuel-air mixture in the cylinder occurs at : a. The end of the power stroke. b. The beginning of the power stroke. (correct) c. The beginning of the exhaust stroke. d. The beginning of the compression stroke. 21. In an internal combustion engine, oil is used to : a. Remove small bits of metal. b. Reduce friction. (correct) c. Prevent gas from leaking around pistons. d. All of the above. 22. As the load changes on an engine, the constant speed is maintained by a: a. Governor. b. Carburetor. c. Throttle. d. All of the above. (correct) 23. The intake and exhaust mechanisms of a two-cycle engine are timed by the : a. Piston. (correct) b. Camshaft. c. Valves. d. Crankshaft. 24. Horsepower is a measure of : a. The amount of work done. b. The rate of doing work. c. The speed of shaft rotation. (correct) d. The amount of heat generated. 25. The first step in starting a spark ignition engine using natural gas as fuel is to : a. Engage the starting motor. b. Turn on the ignition switch. (correct) c. Admit gas into the header line. d. Open the fuel valves, except the valve which lets gas into the header line. 26. Engine speed may be controlled : a. Manually by the throttle. b. Automatically by the governor. c. Both A and B. (correct) d. Neither A nor B. 27. The device that controls the time at which ignition occurs is the: a. Magneto. b. Coil. (correct) c. Distributor. d. Spark plug.
28. At high elevations, engines operating on outside air develop : a. More power than at lower elevations. (correct) b. Less power than at lower elevations. c. About the same power as at lower elevations. d. None of these. 29. The distance a piston travels in one direction is called : a. Clearance. b. Tolerance. c. Stroke. (correct) d. All of the above. 30. During movement of the piston, chemical energy is converted to : a. Work. b. Heat. c. Both A and B. (correct) d. Neither A nor B. 31. Cylinders are : a. Holes bored into the engine block. (correct) b. Holes bored into the piston. c. Part of the crankshaft. d. All of the above. 32. The internal combustion engine produces work by : a. Burning fuel. ( correct) b. Converting electrical energy. c. Producing steam. d. All of the above. 33. The back-and-forth (reciprocating) motion of the piston is converted to : a. The reciprocating motion of the shaft. b. The rotation of the shaft. (correct) c. The reciprocating motion of the cylinder. d. The rotation of the cylinder. 34. The intake and exhaust valves of a four-cycle engine are timed by the : a. Piston. b. Camshaft. (correct) c. Valves. d. Crankshaft. 35. In a diesel engine, fuel and air are mixed in the : a. Cylinder. (correct) b. Fuel pump. c. Carburetor. d. Crankcase.
36. A supercharger is used to compress : a. Air. (correct) b. Gasoline. c. Fuel oil. d. All of the above. 37. A four-cycle engine produces power for every : a. Revolution of the crankshaft. b. Two revolutions of the crankshaft. c. Four revolutions of the crankshaft. (correct) d. Eight revolutions of the crankshaft. 38. A cam fits on the camshaft and is : a. Circular-shaped and centered. b. Oval-shaped and centered. (correct) c. Circular-shaped and off-cutter. d. Oval-shaped and off cutter. 39. When the engine is fully loaded and the load is suddenly removed, the engine is protected from runaway by: a. A centrifugal governor. b. A hydraulic governor. c. A mechanical governor. d. An over speed trip mechanism. (correct) 40. The camshaft of an eight-cylinder, four-cycle engine has : a. 2 cams. b. 4 cams. c. 8 cams. d. 16 cams. (correct) 41. When a fuel-oxygen mixture is burned, the carbon, oxygen and hydrogen react to form : a. Carbon dioxide. (correct) b. Water. c. Both A and B. d. None of these. 42. A two-cycle engine produces power for every : a. Revolution of the crankshaft. b. Two revolutions of the crankshaft. (correct) c. Four revolutions of the crankshaft. d. Eight revolutions of the crankshaft. 43. Compression-ignition engines may be : a. Two-cycle. b. Four-cycle.(correct) c. Either A or B. d. None of the above.
44. The temperature at which the engine runs is controlled by : a. The radiator. b. The thermostat. (correct) c. Air. d. Water. 45. Excessively high oil pressure may be caused by : a. A blocked oil filter. (correct) b. An oil leak in the system. c. Oil being too thin. d. All of the above. 46. The compression ratio in a gasoline engine is : a. Greater than in a diesel. b. Less than in a diesel. (correct) c. About the same as in a diesel. d. None of these. 47. Because the piston moves inside the cylinder : a. No friction occurs. b. Lubrication is not required. c. Lubrication is required. (correct) d. All of the above. 48. Normally, an engine is warmed up at : a. Full-speed with load. b. Full-speed without load. (correct) c. Reduced speed with load. d. Reduced speed without load. 49. A muffler between the exhaust manifold and the end of the exhaust pipe causes : a. A decrease in exhaust gas pressure. (correct) b. An increase in exhaust gas pressure. c. No change in exhaust gas pressure. d. Either A or B. 50. Most large, stationary internal combustion engines are : a. Water cooled. (correct) b. Air cooled. c. Not cooled. d. Either A or B. 51. Types of internal combustion engines : a. Reciprocating engine. b. Rotary engine. c. Both A and B. (correct) d. None of these.
52. Jet engine is type of : a. I.C engine. (correct) b. E.C engine. c. Sterling. d. None of these. 53. Gas turbine engine is a type of : a. E.C engine. b. I.C engine.(correct) c. Rotary engine. d. None of these. 54. Steam turbine is also type of : a. I.C engine. b. E.C engine. (correct) c. Wankel engine. d. None of these. 55. Thermodynamic cycle used for Jet engine is : a. Carnot-cycle. b. Rankin-cycle. c. Brayton-cycle. ( correct) d. None of these. 56. Thermodynamic cycle used for Gas turbine is : a. Otto-cycle. b. Diesel-cycle. c. Rankin-cycle. d. None of the above. (correct) 57. Thermodynamic cycle used for (internal combustion) gasoline engine is : a. Carnot-cycle. b. Otto-cycle. (correct) c. Diesel-cycle. d. Both A and B. 58. Thermodynamic cycle used for (internal combustion) Diesel engine is : a. Otto-cycle. b. Diesel-cycle. (correct) c. Carnot-cycle. d. All of the above. 59. Thermodynamic cycle used for steam turbine is : a. Brayton-cycle. b. Carnot-cycle. c. Rankin-cycle. (correct) d. None of these.
60. Ideal cycle found ever in thermodynamic is : a. Carnot-cycle. (correct) b. Rankin-cycle. c. Brayton-cycle. d. Either A or B. 61. Gasoline engines always require _________________ for combustion. a. S.I system. (correct) b. C.I system. c. Both A and B. d. None of these. 62. Diesel engines always require ____________________ for combustion. a. S.I system. b. C.I system. (correct) c. Both A and B. d. Neither A nor B. 63. Dam created on piston head by the manufacturer’s for the purpose of : a. For homogenous mixture of air-fuel. (correct) b. To look different from others. c. Design purpose only. d. All of the above. 64. For spark ignition _______________ is used : a. Glow plug. b. Spark plug. (correct) c. Fuel injector. d. All of the above. 65. For compression ignition ________________ is used : a. Fuel Injector. b. Atomizer. c. Spark plug. d. Either A or B. (correct) 66. __________________ is used in compression ignition (Diesel) engines to maintain temperature inside the cylinder when it gets cold, for combustion. a. Atomizer. b. Spark plug. c. Fuel injector. d. Glow plug. (correct) 67. In reciprocating type of internal combustion engine : a. Linear motion converted into rotatory motion. (correct) b. Rotational motion converted into linear motion. c. Linear motion converted into rotary motion. d. Rotary motion converted into linear motion.
68. Reciprocating compressor converts ___________ motion into _____________ motion. a. Rotary, Rotatory. b. Linear, Rotatory. c. Linear, Rotary. d. Rotatory, Linear. (correct) 69. Reciprocating engine transfers mechanical energy from piston to crankshaft by using : a. Rocker arm. b. Crank pin. c. Connecting rod. (correct) d. All of the above. 70. In internal combustion engines flywheel is used to : a. To store inertial force. (correct) b. For the balancing of crankshaft. c. Both A and B. d. None of the above. 71. Bearing used in between the connection of connecting rod and crankshaft is : a. Friction bearings. b. Sleeve bearings. c. Journal bearings. d. All of the above. (correct) 72. Counter-weights used to : a. Balance the crankshaft. (correct) b. To splash lubricant inside the crankcase. c. To create gap between cranks in multi-cylinder engine. d. All of the above. 73. Compression rings in the piston : a. Allows gases to go into crankcase. b. Provides sealing between combustion chamber and crankcase. c. Helps exhaust gases to out from exhaust port or valve. d. Both B and C. (correct) 74. Oil rings in the piston : a. Provides sealing between crankcase and combustion chamber. b. Resists lube oil to stay in crankcase. c. Both A and B. (correct) d. None of the above. 75. Turbo & super chargers driven by : a. Engine’s exhaust gases. ( correct) b. Motor. c. Using engine power. d. All of the above.
76. Single overhead cams (SOHC) are found in _______________ cylinder reciprocating engines. a. V-type. b. Inline. (correct) c. Radial. d. All of the above. 77. Dual overhead cams (DOHC) are found in _________________ cylinder reciprocating engines. a. V-type. ( correct) b. Inline. c. W-type. d. All of the above. 78. Separate camshafts for intake and exhaust valves used in : a. OHC. b. SOHC. c. DOHC. (correct) d. None of the above. 79. Inline, Slant, V-type, W-type, Opposed, Radially arranged cylinder engines are all : a. Reciprocating engines. (correct) b. Rotary engines. c. Sterling engines. d. Steam engines. 80. In four stroke engine camshafts operated with the help of : a. Crankshaft. b. Rocker arm. (correct) c. Either A or B. d. None of these. 81. If the temperature of intake air in internal combustion engine increases, then its efficiency will : a. Remain same. b. Decreases.(correct) c. Increases. d. None of these. 82. The operation of forcing additional air under pressure in the engine cylinder is known as : a. Scavenging. b. Turbulence. c. Supercharging.(correct) d. Pre-ignition. 83. The ignition quality of petrol expressed by : a. Cetane number. b. Octane number.(Correct) c. Calorific value. d. All of the above.
84. The mean effective pressure obtained from engine indicator indicates the : a. Maximum pressure developed. b. Minimum pressure. c. Instantaneous pressure at any instant. d. Average pressure.(correct) 85. The probability of knocking in diesel engines is increased by : a. High self-ignition temperature. b. Low volatility. c. High viscosity. d. All of the above.(correct) 86. In a four stroke cycle petrol engine, the compression : a. Starts at 40⁰ after bottom dead Centre and ends at 30⁰ before top dead Centre.(correct) b. Starts at 40⁰ before bottom dead Centre and ends at 30⁰ after bottom dead Centre. c. Starts at bottom dead Centre and ends at top dead Centre. d. May start and end anywhere. 87. The maximum temperature in the I.C engine cylinder is of the order of : a. 500-1000⁰C. b. 1000-1500⁰C. c. 1500-2000⁰C. d. 2000-2500⁰C. (Correct) 88. In compression ignition engines, swirl denotes : a. Haphazard motion of the gases in the chamber.(correct) b. Rotary motion of the gases in the chamber. c. Radial motion of the gases in the chamber. d. None of the above. 89. Supercharging is the process of : a. Supplying the intake of an engine with air at a density greater than the density of the surroundings atmosphere. ( correct) b. Providing forced cooling air. c. Injecting excess fuel for raising more loads. d. Supplying compressed air to remove combustion products fully. 90. The knocking in spark ignition engines can be reduced by : a. Retarding the spark. b. Increasing the engine speed. c. Both A and B. (correct) d. None of these. 91. An engine indicator is used to determine the following : a. Speed. b. Temperature. c. Volume of cylinder. d. M.E.P and I.H.P. (correct)
92. In a four stroke cycle diesel engine, the exhaust valve : a. Opens at 30⁰ before bottom dead Centre and closes at 10⁰ after top dead Centre. (correct) b. Opens at 30⁰ after bottom dead Centre and closes at 10⁰ before top dead Centre. c. Opens at bottom dead Centre and closes at top dead Centre. d. May open and close anywhere. 93. The pressure at the end of compression in the case of diesel engine is of the order of : a. 6 kg/cm. b. 12 kg/cm. c. 20 kg/cm. d. 35 kg/cm. (correct) 94. The fuels in order of decreasing knock tendency for spark ignition engines are : a. Paraffin, aromatic, napthene. b. Paraffin, napthene, aromatic. (correct) c. Napthene, aromatics, paraffin. d. Napthene, paraffin, aromatic. 95. Pour point of fuel oil is the : a. Minimum temperature to which oil is heated in order to give off inflammable vapors in sufficient quantity to ignite momentarily when brought in contact with a flame. b. Temperature at which it solidifies or congeals. (correct) c. It catches fire without external aid. d. Indicated by 90% distillation temperature i.e., when 90% of sample oil has distilled off. 96. Adiabatic compression is one in which : a. Temperature during compression remains constant. b. No heat leaves or enters the system during compression. (correct) c. Work done is maximum. d. Entropy decreases. 97. Airplanes employs following type of compressor in jet engine : a. Radial. b. Axial. (correct) c. Positive displacement. d. Rotary. 98. In a two stroke engine, the working cycle is completed in two revolutions of the crankshaft : a. True. b. False. (correct) c. None of these. d. Neither A nor B.
99. A two stroke cycle engine gives _____________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed : a. Half. b. Same. c. Double. (correct) d. Four times. 100.
The two stroke cycle engine have lighter flywheel : a. True. (correct) b. False. c. None of these.
