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

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
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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 : 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

Last Answer : Ans :c

In SI engines knocking can be reduced by (a) Increasing the compression ratio (b) Increasing the cooling water temperature (c) Retarding the spark advance (d) Increasing the inlet air temperature

Description : In SI engines knocking can be reduced by (a) Increasing the compression ratio (b) Increasing the cooling water temperature (c) Retarding the spark advance (d) Increasing the inlet air temperature

Last Answer : Ans :c

The tendency of knocking in CI engine reduces by (a) High self ignition temperature of fuel (b) Decrease in jacket water temperature (c) Injection of fuel just before TDC (d) Decrease in injection pressure

Description : The tendency of knocking in CI engine reduces by (a) High self ignition temperature of fuel (b) Decrease in jacket water temperature (c) Injection of fuel just before TDC (d) Decrease in injection pressure

Last Answer : Ans :c

In spark ignition engines, the knocking tendency can be decreased by a) decreasing compression ratio b) controlling intake throttle c) controlling ignition timing d) adding dopes like tetraethyl lead and ethylene dibromide

Description : In spark ignition engines, the knocking tendency can be decreased by a) decreasing compression ratio b) controlling intake throttle c) controlling ignition timing d) adding dopes like tetraethyl lead and ethylene dibromide

Last Answer : Answer: d Explanation: None.

The _____________ sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature

Description : The _____________ sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature

Last Answer : Answer: a Explanation: The 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 while the ... gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.

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

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

With increase in __________ Knocking tendency in a spark ignition petrol engine decreases. (A) Supercharging (B) Wall temperature (C) Compression ratio (D) Engine speed

Description : With increase in __________ Knocking tendency in a spark ignition petrol engine decreases. (A) Supercharging (B) Wall temperature (C) Compression ratio (D) Engine speed

Last Answer : Option D

Alcohols alone cannot be used in CI engines as a) their self ignition temperature is high b) latent heat of vaporization is high c) all of the mentioned d) none of the mentioned

Description : Alcohols alone cannot be used in CI engines as a) their self ignition temperature is high b) latent heat of vaporization is high c) all of the mentioned d) none of the mentioned

Last Answer : Answer: c Explanation: None.

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

Description : 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

Last Answer : ANSWER d. all of the above

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

Description : 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

Last Answer : ANSWER d. all of the above

In compression ignition (CI) engine, the compression ratio is a. Cylinder volume / Clearance volume b. Swept Volume / Cylinder Volume c. Clearance volume / Cylinder volume d. Cylinder volume / Swept volume (Ans:a)

Description : In compression ignition (CI) engine, the compression ratio is a. Cylinder volume / Clearance volume b. Swept Volume / Cylinder Volume c. Clearance volume / Cylinder volume d. Cylinder volume / Swept volume (Ans:a)

Last Answer : In two stroke engine there is one power stroke in _____ of crankshaft rotation. a. 90° b. 180° c. 270° d. 360° (Ans:d)

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

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

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 : 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.

Last Answer : ANSWER : A

Morse test is conducted on the engine to calculate the mechanical efficiency of A. single cylinder CI engine B. single cylinder SI engine C. only on two stroke engines D. multi cylinder engine

Description : Morse test is conducted on the engine to calculate the mechanical efficiency of A. single cylinder CI engine B. single cylinder SI engine C. only on two stroke engines D. multi cylinder engine

Last Answer : ANSWER : D

The knocking in spark ignition engines can be reduced by a. Retarding the spark. b. Increasing the engine speed. c. Both a and b d. None of these.

Description : The knocking in spark ignition engines can be reduced by a. Retarding the spark. b. Increasing the engine speed. c. Both a and b d. None of these.

Last Answer : ANSWER c. Both a and b.

The knocking in spark ignition engines can be reduced by a. Retarding the spark. b. Increasing the engine speed. c. Both a and b. d. None of these.

Description : The knocking in spark ignition engines can be reduced by a. Retarding the spark. b. Increasing the engine speed. c. Both a and b. d. None of these.

Last Answer : ANSWER c. Both a and b

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 decrease in pressure ratio C. It increases with decrease in clearance ratio D. It decreases with increases in delivery pressure

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

Last Answer : ANSWER : A

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 consumption, brake power and incylinder pressure. Tutorials on engine performance parameters. Heat balance sheet. Engine performance curves. 1. The increase in intake air temperature into IC engine,___________its efficiency A. increase B. decrease C. does not alter D. unpredictable on

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

Last Answer : ANSWER : B

For the same capacity engines, the compression ratio of diesel engine a. is lower than the compression ratio of SI engine b. is higher than the compression ratio of SI engine c. is same as the compression ratio of SI engine d. cannot say

Description : For the same capacity engines, the compression ratio of diesel engine a. is lower than the compression ratio of SI engine b. is higher than the compression ratio of SI engine c. is same as the compression ratio of SI engine d. cannot say

Last Answer : ANSWER b. is higher than the compression ratio of SI engine

In _____________ sensor, output voltage changes in proportion to air-fuel ratio. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature

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.

_____________ 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

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.

The thermal efficiency of a diesel cycle having fixed compression ratio with increase in cut-off ratio will a. increase b. decrease c. independent d. increase or decrease depending upon other factors

Description : The thermal efficiency of a diesel cycle having fixed compression ratio with increase in cut-off ratio will a. increase b. decrease c. independent d. increase or decrease depending upon other factors

Last Answer : ANSWER b. decrease

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 : 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

Last Answer : ANSWER : C

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

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

If the temperature of intake air in internal combustion engine is lowered, the efficiency will a. increase b. decrease c. remains same d. increases upto certain limit and then decrease

Description : If the temperature of intake air in internal combustion engine is lowered, the efficiency will a. increase b. decrease c. remains same d. increases upto certain limit and then decrease

Last Answer : ANSWER a. increase

If the intake air temperature of Internal combustion engine increases, its efficiency will a. increase b. decrease c.remains same d unpredictable

Description : If the intake air temperature of Internal combustion engine increases, its efficiency will a. increase b. decrease c.remains same d unpredictable

Last Answer : ANSWER b. decrease

Compare SI and CI engine on the basis of air-fuel ratio, power output, emission and knocking.

Description : Compare SI and CI engine on the basis of air-fuel ratio, power output, emission and knocking.

Last Answer : Parameter SI engine CI engine Air-fuel ratio air-fuel ratio is 14.7:1 air-fuel ratio is 20:1 to 70:1  Power output  Power output is Less than CI engine due ... Knocking take place at the end of combustion. Knocking take place at beginning or start of the combustion. 

Anti-knock for compression ignition engines is a) napthene b) tetra ethyl lead c) amyl nitrate d) hexadecane

Description : Anti-knock for compression ignition engines is a) napthene b) tetra ethyl lead c) amyl nitrate d) hexadecane

Last Answer : Answer: c Explanation: Amyl nitrate is the anti-knock for compression ignition engines.

In compression ignition engines, swirl denotes a. Haphazard motion of the gases in the cylinder b. Rotary motion of the gases in the cylinder. c. Radial motion of the gases in the cylinder. d. None of the above

Description : In compression ignition engines, swirl denotes a. Haphazard motion of the gases in the cylinder b. Rotary motion of the gases in the cylinder. c. Radial motion of the gases in the cylinder. d. None of the above

Last Answer : ANSWER a. Haphazard motion of the gases in the chamber

Most high-speed compression engines operate on a. diesel cycle b. Otto cycle c. dual cycle d. Carnot cycle

Description : Most high-speed compression engines operate on a. diesel cycle b. Otto cycle c. dual cycle d. Carnot cycle

Last Answer : ANSWER c. dual cycle

The _____________ sensor, checks the temperature of the ambient air entering the engine for fine tuning the mixture strength. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature

Description : The _____________ sensor, checks the temperature of the ambient air entering the engine for fine tuning the mixture strength. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature

Last Answer : Answer: d Explanation: The air inlet temperature sensor, checks the temperature of the ambient air entering the engine for fine tuning the mixture strength whereas the engine temperature sensor senses the ... gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.

The _____________ sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature

Description : The _____________ sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature

Last Answer : Answer: c Explanation: The air flow sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel while exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.

A diesel engine is usually more efficient than a spark ignition engine because a. Diesel being a heavier hydrocarbon, release more heat per kg than gasoline b. The air standard efficiency of diesel cycle is higher than the Otto cycle, at a fixed compression ratio c. The compression ratio of a diesel engine is higher than that of an Spark ignition engine d.Self ignition temperature of diesel is higher than that of gasoline.

Description : A diesel engine is usually more efficient than a spark ignition engine because a. Diesel being a heavier hydrocarbon, release more heat per kg than gasoline b. The air standard efficiency of diesel ... an Spark ignition engine d.Self ignition temperature of diesel is higher than that of gasoline.

Last Answer : ANSWER c. The compression ratio of a diesel engine is higher than that of an S.I engine

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

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

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 : 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

Last Answer : ANSWER : B

The air fuel ratio in petrol engines is controlled by a. valve opening / closing b. governing c. carburetion d. scavenging

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

The tendency of a petrol engine to knock increases by a. supercharging b. scavenging c. increasing the engine horse power d. reducing the spark advance

Description : The tendency of a petrol engine to knock increases by a. supercharging b. scavenging c. increasing the engine horse power d. reducing the spark advance

Last Answer : ANSWER a. supercharging

The coefficient of performance is the ratio of the refrigerant effect to the (a) heat of compression (b) work done by compressor (c) enthalpy increase in compressor (d) all of the above

Description : The coefficient of performance is the ratio of the refrigerant effect to the (a) heat of compression (b) work done by compressor (c) enthalpy increase in compressor (d) all of the above

Last Answer : Ans: d

The accumulation of carbon in a cylinder results in increase of A. clearance volume B. volumetric efficiency C. ignition time D. effective compression ratio

Description : The accumulation of carbon in a cylinder results in increase of A. clearance volume B. volumetric efficiency C. ignition time D. effective compression ratio

Last Answer : ANSWER : D

The accumulation of carbon in a cylinder results in increase of a. clearance volume b. volumetric efficiency c. ignition time d. effective compression ratio

Description : The accumulation of carbon in a cylinder results in increase of a. clearance volume b. volumetric efficiency c. ignition time d. effective compression ratio

Last Answer : ANSWER d. effective compression ratio

If the compression ratio of an engine working on Otto cycle is increased from 5 to 7 the percentage increase in efficiency will be a. 2% b. 4% c. 8% d. 14%

Description : If the compression ratio of an engine working on Otto cycle is increased from 5 to 7 the percentage increase in efficiency will be a. 2% b. 4% c. 8% d. 14%

Last Answer : ANSWER d. 14%

Mixing of air and fuel in the diesel engine occurs in a. injection pump b. carburetor c. engine cylinder d. inlet manifold

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

An ideal air standard Otto cycle has a compression ratio of 8.5. If the ratio of the specific heats is 1.4, then what is thermal efficiency (in percentage) of the Otto cycle? a. 57.5% b. 45.7% c. 52.5% d. 95%

Description : An ideal air standard Otto cycle has a compression ratio of 8.5. If the ratio of the specific heats is 1.4, then what is thermal efficiency (in percentage) of the Otto cycle? a. 57.5% b. 45.7% c. 52.5% d. 95%

Last Answer : ANSWER a. 57.5%

A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of a) 75% iso-octane and 25% normal heptane b) 75% normal heptane and 25% iso-octane c) 75% petrol and 25% diesel d) 75% diesel and 25% petrol

Description : A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of a) 75% iso-octane and 25% normal heptane b) 75% normal heptane and 25% iso-octane c) 75% petrol and 25% diesel d) 75% diesel and 25% petrol

Last Answer : Answer: a Explanation: None.

A two stroke engine has a speed of 750 rpm. A four stroke engine having an identical cylinder size runs at 1500 rpm. The theoretical output of the two stroke engine will (a) Be twice that of the four stroke engine (b) Be half that of the four stroke engine (c) Be the same as that of the four stoke (d) Depend upon whether it is a CI or SI engine

Description : A two stroke engine has a speed of 750 rpm. A four stroke engine having an identical cylinder size runs at 1500 rpm. The theoretical output of the two stroke engine will (a) Be twice that of the four stroke ... ) Be the same as that of the four stoke (d) Depend upon whether it is a CI or SI engine

Last Answer : Ans :c

If petrol is used in a diesel engine a. higher knocking will occur b. efficiency will be low c. low power will be obtained d. black smoke will be produced

Description : If petrol is used in a diesel engine a. higher knocking will occur b. efficiency will be low c. low power will be obtained d. black smoke will be produced

Last Answer : ANSWER a. higher knocking will occur

Explain the effect of the following engine variables on ignition lag and flame propagation: (i) cylinder size (ii) cylinder wall temperature (iii) compression ratio and (iv) inlet air temperature

Description : Explain the effect of the following engine variables on ignition lag and flame propagation: (i) cylinder size (ii) cylinder wall temperature (iii) compression ratio and (iv) inlet air temperature

Last Answer : (i) Cylinder size - Engine of similar design generally run at the same speed. This is achieved by smaller engine having larger RPM and larger engines having smaller RPM. Due to the same ... all reduces the ignition lag. Pre-increase in the intake temperature and pressure increases the flame speed.

In a centrifugal compressor, an increase in speed at a given pressure ratio causes A. Increase in flow B. Decrease in flow C. Increase in efficiency D. Increase in flow and decrease in efficiency

Description : In a centrifugal compressor, an increase in speed at a given pressure ratio causes A. Increase in flow B. Decrease in flow C. Increase in efficiency D. Increase in flow and decrease in efficiency

Last Answer : ANSWER : D

In a centrifugal compressor an increase in speed at a given pressure ratio causes A. Increase in flow and increase in efficiency B. Increase in flow and decrease in efficiency C. Decrease in flow and increase in efficiency D. Decrease in flow and decrease in efficiency

Description : In a centrifugal compressor an increase in speed at a given pressure ratio causes A. Increase in flow and increase in efficiency B. Increase in flow and decrease in efficiency C. Decrease in flow and increase in efficiency D. Decrease in flow and decrease in efficiency

Last Answer : ANSWER : B

With increase in compression ratio, the volumetric efficiency of air compressor (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease (depends on the suction pressure)

Description : With increase in compression ratio, the volumetric efficiency of air compressor (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease (depends on the suction pressure)

Last Answer : Option A