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1) Supercharging is the process of_____________________? a. supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere b. providing forced cooling air c. injecting excess fuel for raising more load d. supplying compressed air to remove combustion products fully e. raising exhaust pressure
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2) Compression ratio of LC. engines is ___________________? a. the ratio of volumes of air in cylinder before compression stroke and after compression stroke b. volume displaced by piston per stroke and clearance volume in cylinder c. ratio of pressure after compression and before compression d. swept volume/cylinder volume e. cylinder volume/swept volume
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3) The calorific value of gaseous fuels is expressed in terms of__________________? a. kcal b. kcal/kg c. kcal/m2 d. kcal/m² e. all of the above
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4) All heat engines utilize_____________________? a. low heat value of oil b. high heat value of oil c. net claorific value of oil d. calorific value of fuel e. all of the above
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5) Fuel oil consumption guarantees for I .C. engine are usually based on__________________? a. low heat value of oil b. high heat value of oil c. net calorific value of oil d. calorific value of fuel e. all of the above
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6) In case of gas turbines, the gaseous fuel consumption guarantees are based on________________? a. high heat value b. low heat value c. net calorific value d. middle heat value e. calorific value
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7) The pressure and temperature at the end of compression stroke in a petrol engine are of the order of___________________? a. 4 – 6 kg/cm2 and 200 – 250°C b. 6 – 12 kg/cm2 and 250 – 350°C c. 12 – 20 kg/cm2 and 350 – 450°C d. 20 – 30 kg/cm2 and 450 – 500°C e. 30 – 40 kg/cm2 and 500 – 700°C
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8) The maximum temperature in the I.C. engine cylinder is of the order of ________________? a. 500- 1000°C b. 1000- 1500°C c. 1500-2000°C d. 2000-2500°C e. 2500-3000°C
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9) The fuel in diesel engine is normally injected at pressure of_________________? a. 5-10 kg/cm2 b. 20-25 kg/cm2 c. 60-80 kg/cm2 d. 90-130 kg/cm2 e. 150-250 kg/cm2
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10) Crankcase explosion in I.C. engines usuall occurs as ___________________? a. first a mild explosion followed by a bi explosion b. first a big explosion followed by a mil explosion c. both mild and big explosions occi simultaneously d. never occurs e. unpredictable
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11) The specific fuel consumption per BH hour for a petrol engine is approximately__________________? a. 0.15 kg b. 0.2 kg c. 0.25 kg d. 0.3kg e. 0.35 kg
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12) The inlet value of a four stroke cycle I.C engine remains open for nearly___________________? a. 180° b. 125° c. 235° d. 200° e. 275
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13) If one cylinder of a diesel engine receives more fuel than the others, then for that cylinder the________________? a. exhaust will be smoky b. piston rings would stick into piston grooves c. exhaust temperature will be high d. engine starts overheating e. scavenging occurs
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14) It the temperature of intake air in IC engines is lowered, then its efficiency will_______________________? a. increase b. decrease c. remain same d. increase upto certain limit and then decrease e. decrease upto certain limit and then in-crease
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15) For the same compression ratio_____________________? a. Otto cycle is more efficient than the Diesel b. Diesel cycle is more efficient’than Otto c. both Otto and Diesel cycles are, equally efficient d. compression ratio has nothing to do with efficiency e. which is more efficient would depend on engine capacity
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16) As a result of detonation in an I.C. engine, following parameter attains very high value _____________________? a. peak pressure b. rate of rise of pressure c. rate of rise of temperature d. peak temperature e. rate of rise of horse-power
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17) Most high speed compression engines operate on __________________? a. Diesel cycle b. Otto cycle c. Dual combustion cycle d. Special type of air cycle e. Carnot cycle
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18) Which of the following medium is compressed in a Diesel engine cylinder __________________? a. air aione b. air and fuel c. air and lub oil d. fuel alone e. air, fuel and lub oil
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19) In a typical medium speed, 4-stroke cycle diesel engine ___________________? a. fuelinjection starts at 10° before to dead center and ends at 20° after tor dead center b. fuel injection starts at top dead center and ends at 20° after top dead center c. fuel injection starts at just before top dead center and ends just after top deac center d. may start and end anywhere e. none of the above
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20) In diesel engine the diesel fuel injected into cylinder would burn instantly at about compressed air temperature of____________________? a. 250°C b. 500°C c. 1000°C d. 150CPC e. 2000°C
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