McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Uncategorized topics .
| 51. |
which of the following is performed for supercharging of ic engine |
| A. | roots blower |
| B. | axial compressor |
| C. | sliding vane type compressor |
| D. | reciprocationg compressor |
| Answer» B. axial compressor | |
| 52. |
from the engine indicator diagram we obtain |
| A. | indicatecd mean effective pressure |
| B. | brake mean effective pressure |
| C. | mechanical efficiency |
| D. | relative efficiecy |
| Answer» A. indicatecd mean effective pressure | |
| 53. |
the more accurate dynamometer is |
| A. | prony brake type |
| B. | hydraulic type prony |
| C. | swinging field type |
| D. | eddy current type |
| Answer» A. prony brake type | |
| 54. |
the most commonly used dynamometer on account of its simplicity of construction is the |
| A. | brake type |
| B. | hydraulic type prony |
| C. | swinging field type |
| D. | eddy current type |
| Answer» A. brake type | |
| 55. |
brake mean effective pressure in an engine depends upon its |
| A. | speed only |
| B. | torque only |
| C. | speed and torque |
| D. | speed and power |
| Answer» B. torque only | |
| 56. |
brake thermal efficiecny of si engine usually varies between |
| A. | 25-30% |
| B. | 30-60% |
| C. | 60-80% |
| D. | more then 80% |
| Answer» A. 25-30% | |
| 57. |
the brake power is the |
| A. | power availabale at the output of the shaft |
| B. | energy developed inside the cylinder block |
| C. | energy lost dude to friction |
| D. | none of the above |
| Answer» A. power availabale at the output of the shaft | |
| 58. |
the total power developed by the combustion of the fuel is |
| A. | bp |
| B. | ip |
| C. | fp |
| D. | none of the above |
| Answer» B. ip | |
| 59. |
mean effective pressure is the pressure |
| A. | pressure acting on the crank shaft |
| B. | which is acting on the piston through out the power stroke |
| C. | pressure required to inject the fuel in the combustion chamber |
| D. | none of the above |
| Answer» B. which is acting on the piston through out the power stroke | |
| 60. |
fuel air ratio is |
| A. | mass of fuel to mass of air |
| B. | reciprocal of air fuel ratio |
| C. | which affects the combustion phenomenon |
| D. | all of the abov e |
| Answer» D. all of the abov e | |
| 61. |
specific fuel consumption is |
| A. | amount of fuel consumed per unit power developed per hour |
| B. | amount of fuel consumed per unit indicated power developed per hour |
| C. | amount of fuel consumed per hour |
| D. | all of the above |
| Answer» A. amount of fuel consumed per unit power developed per hour | |
| 62. |
heat balance sheet indicates |
| A. | amount of heat energy consumed in the combustion chamber |
| B. | brake up of the total energy input in to different parts |
| C. | amount of energy lost through the exhaust |
| D. | all of the above |
| Answer» B. brake up of the total energy input in to different parts | |
| 63. |
the frictional power is |
| A. | bp+ip |
| B. | bp-ip |
| C. | bpxip |
| D. | none of the above |
| Answer» B. bp-ip | |
| 64. |
identify the correct statement |
| A. | power friction means less brake power |
| B. | lower friction means high barke power |
| C. | higher friction means high brake power |
| D. | none of the above |
| Answer» B. lower friction means high barke power | |
| 65. |
power out put of an engine can be increased by |
| A. | speed |
| B. | compression ratio |
| C. | use of two stroke cycle |
| D. | all of the above |
| Answer» D. all of the above | |
| 66. |
power out put of an engine can be increased by |
| A. | speed |
| B. | charge density |
| C. | compression ratio |
| D. | all of the above |
| Answer» D. all of the above | |
| 67. |
increasing the power out put by increasing the compression ratio is limited by |
| A. | weight to power ratio |
| B. | utilization of energy in fuel |
| C. | air fuel ratio |
| D. | hucr |
| Answer» D. hucr | |
| 68. |
increase in speed to improve B.P is limited by |
| A. | maximum volumetric efficienccy |
| B. | robust engine |
| C. | fuel suply |
| D. | all of the above |
| Answer» D. all of the above | |
| 69. |
utilization of energy in exhaust gases causes power output to |
| A. | increases |
| B. | remains same |
| C. | decreases |
| D. | can not say |
| Answer» A. increases | |
| 70. |
increase in charge density will |
| A. | increases volumetric efficiency |
| B. | power out put |
| C. | both a & b |
| D. | none of the above |
| Answer» C. both a & b | |
| 71. |
supercharging is a process of increasing the |
| A. | pressure in the cylinder |
| B. | suction pressure of charge |
| C. | temprature of the charge |
| D. | charge density |
| Answer» D. charge density | |
| 72. |
supercharging is essential for |
| A. | stationary engine |
| B. | marine engine |
| C. | aircraft engine |
| D. | none of the above |
| Answer» C. aircraft engine | |
| 73. |
power out put of static engine at high alitude compared to power out put at sea level is |
| A. | higher |
| B. | lower |
| C. | same |
| D. | can not predict |
| Answer» D. can not predict | |
| 74. |
objective of superchargin are |
| A. | increase power output |
| B. | reduces weight to power ratio |
| C. | compansate loss of power at high altitudes |
| D. | all of the above |
| Answer» D. all of the above | |
| 75. |
which is not the objectve of supercharging |
| A. | to increase power out put |
| B. | to increase weight to power ratio |
| C. | to increase charge density at high alitude |
| D. | none of the above |
| Answer» B. to increase weight to power ratio | |
| 76. |
an exhaust gas driven blower/ compressor to increase charge density is called |
| A. | supercharger |
| B. | turbocharger |
| C. | both a & b |
| D. | none of the above |
| Answer» D. none of the above | |
| 77. |
a blower/compressor driven by engine shaft to increase charge density is called |
| A. | supercharger |
| B. | turbocharger |
| C. | both a & b |
| D. | none of the above |
| Answer» D. none of the above | |
| 78. |
power out put of an engine compared to turbocharge is |
| A. | more |
| B. | same |
| C. | less |
| D. | can not say |
| Answer» C. less | |
| 79. |
which is not a supercharger |
| A. | centrifugal compressor |
| B. | root blower |
| C. | vane blower |
| D. | pump |
| Answer» D. pump | |
| 80. |
compressed air of turbochar is cooled in aftercooler before supply to engine because it |
| A. | reduceses density of air |
| B. | increases volumetric efficiency |
| C. | increases density of air |
| D. | both b and c |
| Answer» D. both b and c | |
| 81. |
efficiency of turbocharged engine compared to naturally aspirated engine is |
| A. | more |
| B. | same |
| C. | less |
| D. | can not predict |
| Answer» D. can not predict | |
| 82. |
a free piston engine has |
| A. | gear driven supercharger |
| B. | a turbocharger |
| C. | coupled engine, compressor and turbine supercharge |
| D. | gear driven supercharger and separate power turbine |
| Answer» D. gear driven supercharger and separate power turbine | |
| 83. |
Reason for not using very high suction pressure in an engine with the help of supercharger / turbocharger are |
| A. | increased weight |
| B. | increased detonation in si engine |
| C. | increased fp and bearing load |
| D. | all of the above |
| Answer» D. all of the above | |
| 84. |
Reason for not using very high suction pressure in an engine with the help of supercharger / turbocharger are |
| A. | high mean wall and exhaust gas temprature |
| B. | increased detonation in si engine |
| C. | increased weight |
| D. | all of the above |
| Answer» D. all of the above | |
| 85. |
superchargin is usually is not employed in si engine in the following cases |
| A. | static or mobile enigne |
| B. | static engine at high altitude |
| C. | aero enignes at the time of take off |
| D. | none of the above |
| Answer» A. static or mobile enigne | |
| 86. |
superchargin in ci engine is limited by |
| A. | peak pressure and temprature in cylinder |
| B. | mean cylinder wall tempratuer |
| C. | load on bearing and fuel economy |
| D. | all of the above |
| Answer» C. load on bearing and fuel economy | |
| 87. |
A theory in which chain carriers are formed in one step and destroyed in the next step relate to the theory of combustion as |
| A. | preferencial burning of carbon |
| B. | chain reaction theory |
| C. | hydroxylation theory |
| D. | none of the above |
| Answer» B. chain reaction theory | |
| 88. |
Time interval between instant the spark is given and the point a tiny flame appears is called |
| A. | igniton lag |
| B. | ignition delay period |
| C. | ignition delay angle |
| D. | either \a\ or b\ |
| Answer» D. either \a\ or b\ | |
| 89. |
Angle tuned by crank between the point of spark and formation of flame is called |
| A. | igniton lag |
| B. | ignition delay period |
| C. | ignition delay angle |
| D. | either \a\ or b\ |
| Answer» C. ignition delay angle | |
| 90. |
In a vertical engine, the crank angle before TDC at the instant spark is given is called |
| A. | igniton lag |
| B. | ignition delay period |
| C. | ignition delay angle |
| D. | angle of spark advance |
| Answer» D. angle of spark advance | |
| 91. |
The travel of flame speed (m/s) in the S.I. combustion chamber is approximately |
| A. | 5 to 15 |
| B. | 15 to 35 |
| C. | 35 to 50 |
| D. | > 50 |
| Answer» B. 15 to 35 | |
| 92. |
Ignition lag in S.I. engine reduces due to |
| A. | increase in pressure,temperature and compression ratio |
| B. | decrease in pressure,temperature and compression ratio |
| C. | decrease in residual gases |
| D. | both a and c |
| Answer» D. both a and c | |
| 93. |
Minimum ignition lag is obtained when |
| A. | rich mixture(5 to 10%) |
| B. | stoichiometric mixture |
| C. | lean mixture |
| D. | very rich mixture(15 to 30%) |
| Answer» A. rich mixture(5 to 10%) | |
| 94. |
Ignition delay period with increase in speed |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | none of the above |
| Answer» C. remains same | |
| 95. |
Ignition delay angle________with increase in speed |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | none of the above |
| Answer» A. increases | |
| 96. |
The speed of the flame propagation increases with increase in |
| A. | compression ratio |
| B. | suction pressure and temperatur |
| C. | slightly rich mixtures |
| D. | all of the above |
| Answer» D. all of the above | |
| 97. |
Increase in turbulence________the flame speeds |
| A. | increases |
| B. | decreases |
| C. | doesn\t affect |
| D. | none of the above |
| Answer» A. increases | |
| 98. |
Increase in speed of the engine________the flame speeds |
| A. | increases |
| B. | decreases |
| C. | doesn\t affect |
| D. | none of the above |
| Answer» A. increases | |
| 99. |
Increase in the size of similar engines__________the crank angle turned during flame travel across the cylinder |
| A. | increases |
| B. | decreases |
| C. | doesn\t affect |
| D. | none of the above |
| Answer» C. doesn\t affect | |
| 100. |
Flame speed in combustion chamber during flame travel are |
| A. | high at beginning and at the end whereas low in the middle |
| B. | low at beginning and end and high in the middle |
| C. | constant throught |
| D. | cannot predict |
| Answer» B. low at beginning and end and high in the middle | |
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