Description : 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
Last Answer : ANSWER : A
Description : The air-fuel ratio of the petrol engine is governed by A. fuel pump B. governor C. carburetor D. injector
Last Answer : ANSWER : C
Description : Mixing of air and fuel in the diesel engine occurs in a. injection pump b. carburetor c. engine cylinder d. inlet manifold
Last Answer : ANSWER c. engine cylinder
Description : Rate of burning in the compression ignition engine can be controlled by a. rate of injection of fuel b. rate of air taken into carburetor c. both a. and b. d. none of the above
Last Answer : ANSWER a. rate of injection of fuel
Description : In a carburetor the level of the fuel in the float chamber as compared to the level of the main jet in the venture is A. lower B. same C. higher D. same or higher
Description : Vapour lock is a. complete or partial stoppage of fuel supply due to vaporization of the fuel b. locking of carburetor due to high vapor pressure c. excess fuel supply to the engine d. supply of liquid fuel to the engine
Last Answer : ANSWER a. complete or partial stoppage of fuel supply due to vaporization of the fuel
Description : When humidity ratio of air ____ air is said to be dehumidified. A. increases B. decreases C. remains constant D. none of the mentioned
Last Answer : ANSWER : B
Description : Which one of the following statement is not correct for the volumetric efficiency of a reciprocating air compressor? A. It decreases with increase in ambient temperature B. It increases with ... It increases with decrease in clearance ratio D. It decreases with increases in delivery pressure
Description : Which one of the following statements are correct for reciprocating air compressor? A. Its volumetric efficiency increases with increasing clearance ratio B. Its volumetric efficiency increases ... ratio D. Its volumetric efficiency decreases with increasing clearance ratio and pressure ratio
Last Answer : ANSWER : D
Description : Volumetric efficiency of a compressor without clearance volume A. Increases with increase in compression ratio B. Decreases wit increase in compression ratio C. Not dependent upon compression ratio D. Unpredictable
Description : How the efficiency of the SI engine is affected by the specific heat ratio (γ) of the working fluid? a. the efficiency of the engine increases with increase in specific heat ratio (γ) of the working ... not affected by change in specific heat ratio (γ) of the working fluid d. none of the above
Last Answer : ANSWER a. the efficiency of the engine increases with increase in specific heat ratio (γ) of the working fluid
Description : What is the relation between compression ratio (rk) and the efficiency of the Otto cycle? a. efficiency decreases with increase in compression ratio b. efficiency increases with increase in compression ratio c. efficiency is not affected by change in compression ratio d. none of the above
Last Answer : ANSWER b. efficiency increases with increase in compression ratio
Description : The tendency of a diesel engine to knock increases if a. engine speed is increased b. engine power is increased c. cetane number of the fuel is increased d. compression ratio is increased
Last Answer : ANSWER d. compression ratio is increased
Description : Use of gasoline blend like tetraethyl lead in internal combustion engine a. increases the octane rating of the fuel b. allows engine to operate at higher compression ratio c. avoids auto-ignition of fuel d. all of the above
Last Answer : ANSWER d. all of the above
Description : Velocity of flame propagation in SI engine is maximum for a fuel air mixture which is (a) 10% richer than stoichiometric (b) Equal to stoichiometric (c) More than 10% richer than stoichiometric (d) 10% leaner than stoichiometric
Last Answer : Ans :a
Description : Supercharging is the process of a. supplying the engine with air at a density greater than the density of the surrounding atmosphere b. providing forced cooling air c. injecting excess fuel d. raising the exhaust pressure
Last Answer : ANSWER a. supplying the engine with air at a density greater than the density of the surrounding atmosphere
Description : Work input to the air compressor with n as index of compression A. Increases with increase in value of n B. Decrease with increase in value of n C. remains same whatever the value of n D. first increase and then decreases with increase of value of n.
Description : In a reciprocating air compressor the compressor work per kg of air A. Increases as clearance volume increases B. Decreases as clearance volume increases C. Is independent of clearance volume D. Increases with clearance volume only of multistage compressor
Description : The power required to drive a turbo compressor for a given pressure ratio decreases when A. Air is heated at entry B. Air is cooled at entry C. Air is cooled at exit D. Air is heated at exit
Description : Air fuel ratio at which a petrol engine cannot work is A. 8:1 B. 12:1 C. 15:1 D. 20:1 and less
Description : Air fuel ratio for idling speed of a petrol engine is approximately A. 1:1 B. 5:1 C. 20:1 D. 10:1
Description : The theoretically correct air fuel ratio of a petrol engine is of the order of A. 6:1 B. 10:1 C. 15:1 D. 20:1
Description : In _____________ sensor, output voltage changes in proportion to air-fuel ratio. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: b Explanation: Only in exhaust gas sensor, output voltage changes in proportion to air-fuel ratio.
Description : _____________ senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio. a) Engine temperature b) Exhaust gas c) Air flow d) Air inlet temperature
Last Answer : Answer: b Explanation: Exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates airfuel ratio while engine temperature sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting.
Description : The stoichiometric air fuel ration for petrol is 15:1 . What is the air fuel ratio required for maximum power? (a) 16:1 – 18:1 (b) 15:1 (c) 12:1 – 14:1 (d) 9:1 – 11:1
Last Answer : Ans :c
Description : If the performance of diesel engine of different sizes, cylinder dimensions and power rating are to be compared, which of the following parameters can be used for such comparison? (a) Swept volume (b) Air fuel ratio (c) Specific brake fuel consumption (d) Volumetric efficiency
Description : Air fuel ratio at which a petrol engine cannot work is a. 8:1 b. 10:1 c. 20:1 and less d. 15:1
Last Answer : ANSWER c. 20:1 and less
Description : The theoretically correct air fuel ratio for petrol engine is of the order of a.6 : 1 b. 9 : 1 c. 12 : 1 d. 15 : 1
Last Answer : Answer d. 15:1
Description : The air fuel ratio in petrol engines is controlled by a. valve opening / closing b. governing c. carburetion d. scavenging
Last Answer : ANSWER c. carburetion
Description : When the humidity ratio of air increases the air is said to be A. dehumidified B. humidified C. heated D. cooled
Description : The knocking tendency in CI engines increases with (a) Increase of coolant water temperature (b) Increase of temperature of inlet air (c) Decrease of compression ratio (d) Increase of compression ratio
Description : In a refrigeration cycle, the super heating……..C.O.P (a)decreases (b)does not change (c) increases (d)none of the above
Last Answer : Ans: a
Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP
Description : Superheating in a refrigeration cycle (a) increases COP (b) decreases COP (c) COP remains unaltered (d) other factors decide COP
Last Answer : Ans: b
Description : At lower temperatures and pressures, the latent heat of vaporization of a refrigerant (a) decreases (b) increases (c) remains same (d) depends on other factors
Description : Formation of frost on evaporator in refrigerator (a) results in loss of heat due to poor heat transfer (b) increases heat transfer rate (c) decreases compressor power. (d) can be avoided by proper design
Description : In sensible cooling process the relative humidity: A. decreases B. increases C. remains constant D. none of the above
Description : In a battery ignition system, the intensity of spark is A. minimum at low engine speed B. minimum at low engine speed and increases with engine speed C. maximum al low engine speed and decreases with engine speed D. maximum at low engine speed
Description : The critical spark energy required to ignite a given mixture A. decreases with decreasing sparking voltage B. increases with decreasing sparking voltage C. increases with increasing sparking voltage D. decreases with increasing sparking voltage
Description : Supercharging of an IC engine is done so that the A. thermal efficiency increases B. power output increases C. speed of the engine increases D. power output decreases
Description : HUCR is the highest compression ratio at which the A. engine can be run B. engine gives maximum output C. engine is most efficient D. fuel can be used in a test engine without detonation
Description : The compression ratio cannot be increased beyond certain limit as it results in a. auto-ignition of fuel b. detonation c. engine knocking d. all the above
Last Answer : ANSWER d. all the above
Description : Which of the following factors increases the tendency of knocking in the CI engines? (a) Increasing both the r and coolant temperatures (b) Increasing both the speed and the injection advance (c) Increasing the speed, injection advance and coolant temperature (d) Increasing the compression ratio
Description : Solid injection in CI engine means injection of A. solid fuel only B. liquid fuel only C. liquid fuel and air D. solid fuel and air
Description : In diesel engine the fuel injected would burn instantaneously at about compressed air temperature of A. 1000°C B. 250°C C. 450°C D. 2000°C
Description : Which of the following is compressed in a diesel engine cylinder A. air B. fuel C. air and fuel D. air and lub oil
Description : The output of a diesel engine can be increased without increasing the engine speed or size in the following way A. feeding more fuel B. increasing the flywheel size C. heating intake air D. supercharging
Description : In four stroke engine which of the following is also known as power stroke a. Suction stroke b. Compression stroke c. Expansion stroke d. Exhaust stroke (Ans:c) Measurements of fuel and air ... into IC engine,___________its efficiency A. increase B. decrease C. does not alter D. unpredictable on
Description : In _____________ injection system only one pump is sufficient for multi-cylinder engine. a) air b) mechanical c) compression fuel d) common rail
Last Answer : Answer: d Explanation: None.
Description : Solid injection is also called ________________ a) air injection b) mechanical injection c) compression fuel injection d) none of the mentioned
Last Answer : Answer: b Explanation: Generally, solid injection is also called mechanical injection.