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

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  
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ANSWER  b. efficiency increases with increase in compression ratio
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What is the formula for compression (rk) ratio of the Otto cycle? a. rk = Volume of cylinder at the beginning of compression / Volume of cylinder at the end of compression b. rk = Volume of cylinder at the end of compression / Volume of cylinder at the beginning of compression c. rk = Volume of cylinder at the end of compression / clearance volume d. none of the above

Description : What is the formula for compression (rk) ratio of the Otto cycle? a. rk = Volume of cylinder at the beginning of compression / Volume of cylinder at the end of compression b. rk = Volume of cylinder ... c. rk = Volume of cylinder at the end of compression / clearance volume d. none of the above

Last Answer : ANSWER a. rk = Volume of cylinder at the beginning of compression / Volume of cylinder at the end of compression

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%

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

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%

For same compression ratio a. Diesel cycle has lower efficiency than Otto cycle b. Diesel cycle has higher efficiency than Otto cycle c. Diesel cycle and Otto cycle have equal efficiencies d. Depends upon the load on engine

Description : For same compression ratio a. Diesel cycle has lower efficiency than Otto cycle b. Diesel cycle has higher efficiency than Otto cycle c. Diesel cycle and Otto cycle have equal efficiencies d. Depends upon the load on engine

Last Answer : Answer a. Diesel cycle has lower efficiency than Otto cycle

The efficiency of the Otto cycle is independent of a. Heat supplied b. Compression ratio c. Ratio of specific heats d. None of the above

Description : The efficiency of the Otto cycle is independent of a. Heat supplied b. Compression ratio c. Ratio of specific heats d. None of the above

Last Answer : Answer a. Heat supplied

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 fluid b. the efficiency of the engine decreases with increase in specific heat ratio (γ) of the working fluid c. the efficiency of the engine does not affected by change in specific heat ratio (γ) of the working fluid d. none of the above

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

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

With increase in compression ratio, the efficiency of the otto engine (A) Increases (B) Decreases (C) Remain constant (D) Increases linearly

Description : With increase in compression ratio, the efficiency of the otto engine (A) Increases (B) Decreases (C) Remain constant (D) Increases linearly

Last Answer : (A) Increases

For same compression ratio and heat input a. Otto cycle is more efficient b. Diesel cycle is more efficient c. Both are equally efficient d. None of the above

Description : For same compression ratio and heat input a. Otto cycle is more efficient b. Diesel cycle is more efficient c. Both are equally efficient d. None of the above

Last Answer : ANSWER a. Otto cycle is more efficient

For an engine operating on air standard Otto cycle, the clearance volume is 10% of the swept volume. The specific heat ratio of air is 1.4. The air standard cycle efficiency is a. 38.3 % b. 39.8 % c. 60.2 % d. 61.7 %

Description : For an engine operating on air standard Otto cycle, the clearance volume is 10% of the swept volume. The specific heat ratio of air is 1.4. The air standard cycle efficiency is a. 38.3 % b. 39.8 % c. 60.2 % d. 61.7 %

Last Answer : ANSWER d. 61.7%

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

Most high speed compression ignition engine operate on A. dual cycle B. otto cycle C. diesel cycle D.Carnot cycle

Description : Most high speed compression ignition engine operate on A. dual cycle B. otto cycle C. diesel cycle D.Carnot cycle

Last Answer : ANSWER : A

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

Which of the following cycle is used for Compression Ignition engine? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle

Description : Which of the following cycle is used for Compression Ignition engine? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle

Last Answer : Answer b. Diesel cycle

For the same maximum pressure and temperature, what is the relation among the efficiencies of the Otto cycle, the Diesel cycle and the Dual cycle? a. ηDual >ηDiesel >ηOtto b. ηDiesel >ηDual >ηOtto c. ηDiesel >ηOtto >ηDual d. ηOtto >ηDiesel >ηDual

Description : For the same maximum pressure and temperature, what is the relation among the efficiencies of the Otto cycle, the Diesel cycle and the Dual cycle? a. ηDual >ηDiesel >ηOtto b. ηDiesel >ηDual >ηOtto c. ηDiesel >ηOtto >ηDual d. ηOtto >ηDiesel >ηDual

Last Answer : ANSWER b. ηDiesel >ηDual >ηOtto

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

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 with pressure ratio C. Its volumetric efficiency does not vary with change in clearance ratio and pressure ratio D. Its volumetric efficiency decreases with increasing clearance ratio and pressure ratio

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

The ratio of work done per cycle to the stroke volume of the compressor is known as A. Compressor capacity B. Compression ratio C. Compressor efficiency D. Mean effective pressure

Description : The ratio of work done per cycle to the stroke volume of the compressor is known as A. Compressor capacity B. Compression ratio C. Compressor efficiency D. Mean effective pressure

Last Answer : ANSWER : D

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

An engine working on air standard Otto cycle has a cylinder diameter of 10 cm and stroke length of 15 cm. The ratio of specific heats for air is 1.4. If the clearance volume is 196.3 cc and the heat supplied per kg of air per cycle is 1800 kJ/kg, then work output per cycle per kg of air is a. 879.1 kJ/ b. 890.2 kJ c. 895.3 kJ d. 973.5 kJ

Description : An engine working on air standard Otto cycle has a cylinder diameter of 10 cm and stroke length of 15 cm. The ratio of specific heats for air is 1.4. If the clearance volume is 196.3 cc and the heat supplied per kg of air per ... kg of air is a. 879.1 kJ/ b. 890.2 kJ c. 895.3 kJ d. 973.5 kJ

Last Answer : ANSWER d. 973.5 kJ

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

Pick out the correct statement. (A) Compression ratio of an Otto engine is comparatively higher than a diesel engine (B) Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio (C) Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat (D) Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work

Description : Pick out the correct statement. (A) Compression ratio of an Otto engine is comparatively higher than a diesel engine (B) Efficiency of an Otto engine is higher than that of a diesel ... Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work

Last Answer : (B) Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio

Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle  A. combustion is at constant volume  B. expansion and compression are isentropic  C. maximum temperature is higher  D. heat rejection is lower

Description : Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle  A. combustion is at constant volume  B. expansion and compression are isentropic  C. maximum temperature is higher  D. heat rejection is lower

Last Answer : Answer: D

For same compression ratio and for same heat added  (a) Otto cycle is more efficient than Diesel cycle  (b) Diesel cycle is more efficient than Otto cycle  (c) efficiency depends on other factors  (d) both Otto and Diesel cycles are equally efficient  (e) none of the above.

Description : For same compression ratio and for same heat added  (a) Otto cycle is more efficient than Diesel cycle  (b) Diesel cycle is more efficient than Otto cycle  (c) efficiency depends on other factors  (d) both Otto and Diesel cycles are equally efficient  (e) none of the above.

Last Answer : Answer : a

In otto cycle compression ratio is 8. Calculate air standard efficiency. Will it be grater than Carnot Cycle ? Justify your answer.

Description : In otto cycle compression ratio is 8. Calculate air standard efficiency. Will it be grater than Carnot Cycle ? Justify your answer. 

Last Answer : No, the Otto cycle efficiency 56.47% will always be lower than Carnot cycle efficiency. Justification: Carnot theorem states that keeping operating conditions same, Carnot engine is more efficient than any other engine. So, Otto cycle efficiency is lower than Carnot cycle efficiency. 

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 : 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

Last Answer : Ans :c

In a refrigeration cycle, the super heating……..C.O.P (a)decreases (b)does not change (c) increases (d)none of the above

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

The air standard Otto cycle comprises a two constant pressure processes and two constant volume processes b two constant pressure and two constant entropy processes c. two constant volume processes and two constant entropy processes d. none of the above.

Description : The air standard Otto cycle comprises a two constant pressure processes and two constant volume processes b two constant pressure and two constant entropy processes c. two constant volume processes and two constant entropy processes d. none of the above.

Last Answer : ANSWER (c) two constant volume processes and two constant entropy processes

For the same peak pressure and heat input a. Otto cycle is more efficient b. Diesel cycle is more efficient c. Both are equally efficient d. None of the above

Description : For the same peak pressure and heat input a. Otto cycle is more efficient b. Diesel cycle is more efficient c. Both are equally efficient d. None of the above

Last Answer : ANSWER b. Diesel cycle is more efficient

Which of the following cycle is used for Spark Ignition engine? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle

Description : Which of the following cycle is used for Spark Ignition engine? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle

Last Answer : Answer a. Otto cycle

In which of the following cycle heat is added at constant pressure? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle

Description : In which of the following cycle heat is added at constant pressure? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle

Last Answer : Answer b. Diesel cycle

In which of the following cycle heat is added at constant volume? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle

Description : In which of the following cycle heat is added at constant volume? a. Otto cycle b. Diesel cycle c. Dual cycle d. Carnot cycle

Last Answer : Answer a. Otto cycle

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

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 : 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

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

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

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

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

Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP

Description : Under-cooling in a refrigeration cycle (a) increases COP (b) decreases COF (c) COP remains unaltered (d) other factors decide COP

Last Answer : Ans: a

Superheating in a refrigeration cycle (a) increases COP (b) decreases COP (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

The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called a. net efficiency b. efficiency ratio c. relative efficiency d. overall efficiency

Description : The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called a. net efficiency b. efficiency ratio c. relative efficiency d. overall efficiency

Last Answer : ANSWER c. relative efficiency

The efficiency of an Otto engine compared to that of a diesel engine, for the same compression ratio will be (A) More (B) Less (C) Same (D) Data insufficient to predict

Description : The efficiency of an Otto engine compared to that of a diesel engine, for the same compression ratio will be (A) More (B) Less (C) Same (D) Data insufficient to predict

Last Answer : (A) More

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

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

When humidity ratio of air ____ air is said to be dehumidified. A. increases B. decreases C. remains constant D. none of the mentioned

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

In a simple carburetor, the air-fuel ratio increases when the A. density of air increases B. velocity of air increases C. velocity of air decreases D. density of air decreases

Description : In a simple carburetor, the air-fuel ratio increases when the A. density of air increases B. velocity of air increases C. velocity of air decreases D. density of air decreases

Last Answer : ANSWER : B

The advantage of dry compression is that (a) it permits higher speeds to be used (b) it permits complete evaporation in the evaporator (c) it results in high volumetirc and mechanical efficiency (d) all of the above

Description : The advantage of dry compression is that (a) it permits higher speeds to be used (b) it permits complete evaporation in the evaporator (c) it results in high volumetirc and mechanical efficiency (d) all of the above

Last Answer : Ans: d