An air-standard Diesel cycle consists of the following processes:1-2: Air is compressed isentropically.2-3: Heat is added at constant pressure.3-4: Air expands isentropically to the original volume.4-1: Heat is rejected at constant volume.If γ and T denotes the specific heat ratio and temperature, respectively the efficiency of the cycle is

\(1 - \frac{{\gamma \left( {{T_4} - {T_1}} \right)}}{{{T_3} - {T_2}}}\)

\(1 - \frac{{{T_4} - {T_1}}}{{{T_3} - {T_2}}}\)

\(1 - \frac{{{T_4} - {T_1}}}{{\gamma \left( {{T_3} - {T_2}} \right)}}\)

\(1 - \frac{{\gamma \left( {{T_4} - {T_1}} \right)}}{{{T_3} - {T_2}}}\)

\(1 - \frac{{{T_4} - {T_1}}}{{\left( {\gamma - 1} \right)\left( {{T_3} - {T_2}} \right)}}\)

In air standard cycle analysis of IC engines, which of the following statements is correct?

Compression and expansion processes are considered as irreversible.

Specific heats (Cp, Cv) of air vary with temperature.

There will be a sudden change in chemical equilibrium of the working fluid.

There are no intake or exhaust processes.

Compression and expansion processes are considered as irreversible.

For same compression ratio and heat addition, the efficiency of otto, diesel and dual cycle may compared as

ηdiesel cycle > ηdual cycle > ηotto cycle

ηdiesel cycle > ηotto cycle > ηdual cycle

ηotto cycle > ηdiesel cycle > ηdual cycle

ηotto cycle > ηdual cycle > ηdiesel cycle

Otto cycle of a car engine consists of:

two isochore and two reversible adiabatic cycles

Diesel cycle consists of which four processes?

two isentropic and two constant pressures

two isothermal and two isentropic

two isentropic and two constant volumes

two isentropic, one constant volume and one constant pressure

two isentropic and two constant pressures

A heat engine works on dual cycle. It contains:

two isentropic, two isothermal and one isobaric processes

two adiabatic, two isothermal and one isobaric processes

two isentropic, two isochoric, and one isobaric processes

two isentropic, two isothermal and one isobaric processes

two adiabatic, two isochoric and one isobaric processes

Otto cycle consist of following four processes

Two isentropic, one constant and one constant pressure

Two isothermals and two isentropic

Two isentropic and two constant volumes

Two isentropic, one constant and one constant pressure

Two isentropic and two constant pressures

Match List – I (Details of process of the cycle) with List – II (Name of the cycle) and select correct answer using the codes given below the lists:List – IA. Two isothermals and two adiabaticsB. Two isothermals and two constant volumesC. Two adiabatics and two constant volumesD. Two adiabatics and two constant pressuresList – II1. Otto2. Joule3. Carnot4. Stirling

A – 4, B – 3, C – 2, D - 1

A – 3, B – 4, C – 1, D - 2

A – 4, B – 3, C – 2, D - 1

A – 4, B – 3, C – 1, D - 2

A – 3, B – 4, C – 2, D - 1

A high-speed diesel engine theoretically operates on ________?

mixed cycle of constant pressure and constant volume

In SI engines for higher thermal efficiency

Heat liberation during combustion should be maximum

Compression ratio should be high

Heat liberation during combustion should be maximum

Surface to volume ratio should be high

An air standard Otto cycle consists of ______.

Constant pressure heat rejection

Combustion process partly at constant volume and partly at constant pressure

If Tmax and Tmin be the maximum and minimum temperatures in an Otto cycle, then for the ideal conditions, the temperature after compression should be

\(T_{min} + \dfrac{T_{max}-T_{min}}{2}\)

\(\dfrac{T_{max} + T_{min}}{2}\)

\(\sqrt{\dfrac{T_{max}}{T_{min}}}\)

\(\sqrt{T_{max}\times T_{min}}\)

\(T_{min} + \dfrac{T_{max}-T_{min}}{2}\)

In an Otto cycle, how does heat addition takes place?

Irreversibly at constant pressure

Irreversibly at constant volume

Reversibly at constant pressure

A diesel engine is usually more efficient than a spark ignition engine because

Self-ignition temperature of diesel is higher than that of gasoline

Diesel being heavier hydrocarbon, releases more heat per kg than gasoline

The air standard efficiency of diesel cycle is higher than the Otto cycle, at a fixed compression ratio

The compression ratio of a diesel engine is higher than that of an SI engine

Self-ignition temperature of diesel is higher than that of gasoline

An ideal cycle is shown in the figure below. Its thermal efficiency is given by

\(1 - \frac{1}{\gamma }\frac{{\left( {{p_2} - {p_1}} \right)}}{{\left( {{V_3} - {V_1}} \right)}}\frac{{{V_1}}}{{{p_1}}}\)

\(\frac{{\left( {\frac{{{V_3} - 1}}{{{V_1}}}} \right)}}{{\left( {\frac{{{p_2}}}{{{p_1}}} - 1} \right)}}\)

\(1 - \frac{1}{\gamma }\frac{{\left( {\frac{{{v_3} - 1}}{{{V_1}}}} \right)}}{{\left( {\frac{{{p_2}}}{{{p_1}}} - 1} \right)}}\)

\(1 - \gamma \frac{{\left( {{V_3} - {V_1}} \right)}}{{\left( {{p_2} - {p_1}} \right)}}\frac{{{p_1}}}{{{V_1}}}\)

\(1 - \frac{1}{\gamma }\frac{{\left( {{p_2} - {p_1}} \right)}}{{\left( {{V_3} - {V_1}} \right)}}\frac{{{V_1}}}{{{p_1}}}\)

Compression ratio of an internal combustion engine is defined as _______.[VS = Swept volume, VC = Clearance volume]

\(\frac{{{V_c} + {V_s}}}{{{V_s}}}\)

\(\frac{{{V_c}}}{{{V_s} + {V_c}}}\)

\(\frac{{{V_c} + {V_s}}}{{{V_c}}}\)

For the same compression ratio, the efficiency of an air standard Otto cycle is

Less than the efficiency of an air standard diesel cycle

More than the efficiency of an air standard Diesel cycle

Less than the efficiency of an air standard diesel cycle

Equal to the efficiency of an air standard Diesel cycle

73 + Mcqs in Ic Engine Cycles in Mechanical Engineering Page 1 McqOptions

1.	For the same heat input and compression ratio, the most efficient cycle is
A.	Otto cycle
B.	Diesel cycle
C.	Dual cycle
D.	None of these
Answer» B. Diesel cycle

Discussion

2.	An air-standard Diesel cycle consists of the following processes:1-2: Air is compressed isentropically.2-3: Heat is added at constant pressure.3-4: Air expands isentropically to the original volume.4-1: Heat is rejected at constant volume.If γ and T denotes the specific heat ratio and temperature, respectively the efficiency of the cycle is
A.	\(1 - \frac{{{T_4} - {T_1}}}{{{T_3} - {T_2}}}\)
B.	\(1 - \frac{{{T_4} - {T_1}}}{{\gamma \left( {{T_3} - {T_2}} \right)}}\)
C.	\(1 - \frac{{\gamma \left( {{T_4} - {T_1}} \right)}}{{{T_3} - {T_2}}}\)
D.	\(1 - \frac{{{T_4} - {T_1}}}{{\left( {\gamma - 1} \right)\left( {{T_3} - {T_2}} \right)}}\)
Answer» C. \(1 - \frac{{\gamma \left( {{T_4} - {T_1}} \right)}}{{{T_3} - {T_2}}}\)

Discussion

3.	In an Ideal Otto cycle the air standard efficiency is 56.5%. if the heat added during the constant volume process is 1000 kJ/kg, determine the work done.
A.	1000 kJ/kg
B.	1500 kJ/kg
C.	565 kJ/kg
D.	None of the above
Answer» D. None of the above

Discussion

4.	In an Otto cycle, the compression ratio is 9 : 1 and the pressure and temperature at the beginning of the compression process are 100 kPa and 10°C. The heat addition by combustion gives the highest temperature as 2500 K.Thermal efficiency of the cycle is:
A.	68.47%
B.	48.57%
C.	38.47%
D.	58.47%
Answer» E.

Discussion

5.	An Otto cycle has a compression ratio of 8. If 250 kJ of work is extracted from the cycle, the heat rejected by the cycle is
A.	500 kJ
B.	442.69 kJ
C.	331.4 kJ
D.	192.69 kJ
Answer» E.

Discussion

6.	Consider the following statements:1. Both Otto and Diesel cycles are special cases of dual combustion cycle2. Combustion process in IC engines is neither fully constant volume nor fully constant pressure process3. Combustion process in ideal cycle is replaced by heat addition from internal source in closed cycle4. Exhaust process is replaced by heat rejection in ideal cycleWhich of the above statements are correct?
A.	1, 2 and 3 only
B.	3 and 4 only
C.	1, 2 and 4 only
D.	1, 2, 3 and 4
Answer» D. 1, 2, 3 and 4

Discussion

7.	In an Otto cycle, the compression ratio is 9 : 1, and the pressure and temperature at the beginning of the compression process are 100 kPa and 10° C respectively. The heat addition by combustion gives the highest temperature as 2500 K. The highest cycle pressure is:
A.	7.95 MPa
B.	2.17 MPa
C.	1.39 MPa
D.	8.50 MPa
Answer» B. 2.17 MPa

Discussion

8.	An otto cycle has a compression ratio of 9. If 1000 kJ of work is extracted from the cycle, the heat rejected by the cycle is (take γ = 1.5)
A.	500 kJ
B.	125 kJ
C.	250 kJ
D.	1000 kJ
Answer» B. 125 kJ

Discussion

9.	In air standard cycle analysis of IC engines, which of the following statements is correct?
A.	Specific heats (Cp, Cv) of air vary with temperature.
B.	There will be a sudden change in chemical equilibrium of the working fluid.
C.	There are no intake or exhaust processes.
D.	Compression and expansion processes are considered as irreversible.
Answer» D. Compression and expansion processes are considered as irreversible.

Discussion

10.	In an Otto cycle, air is compressed from 3 litres to 2.4 litres from a starting pressure of 1.5 kg/cm2. The net output per cycle is 400 kJ. What is the mean effective pressure (MPa) of the cycle?
A.	500
B.	567
C.	667
D.	700
Answer» D. 700

Discussion

11.	For same compression ratio and heat addition, the efficiency of otto, diesel and dual cycle may compared as
A.	ηdiesel cycle > ηdual cycle > ηotto cycle
B.	ηdiesel cycle > ηotto cycle > ηdual cycle
C.	ηotto cycle > ηdiesel cycle > ηdual cycle
D.	ηotto cycle > ηdual cycle > ηdiesel cycle
Answer» E.

Discussion

12.	An I.C engine works with a compression ratio of 16. If cut-off happens at 8% of the stroke, then the cut-off ratio of this engine is:
A.	1.2
B.	2.2
C.	4.2
D.	3.2
Answer» C. 4.2

Discussion

13.	An air standard Otto cycle has volumetric compression ratio of 6, the lowest cycle pressure of 0.1 MPa and operates between temperature limits of 27°C and 1569°C. what is the temperature after isentropic expansion if ratio of specific heats is 1.4?
A.	600 K
B.	700 K
C.	900 K
D.	1000 K
Answer» D. 1000 K

Discussion

14.	A four-stroke petrol engine theoretically operates on:
A.	Joule cycle
B.	Otto cycle
C.	Brayton cycle
D.	Bell coleman cycle
Answer» C. Brayton cycle

Discussion

15.	For given compression ratio in the otto cycle, which of the following will give the highest efficiency?
A.	Air
B.	Argon
C.	Oxygen
D.	Nitrogen
Answer» C. Oxygen

Discussion

16.	Otto cycle of a car engine consists of:
A.	one adiabatic cycle only
B.	one isochore cycle only
C.	two isochore and two reversible adiabatic cycles
D.	four adiabatic cycles
Answer» D. four adiabatic cycles

Discussion

17.	Diesel cycle consists of which four processes?
A.	two isothermal and two isentropic
B.	two isentropic and two constant volumes
C.	two isentropic, one constant volume and one constant pressure
D.	two isentropic and two constant pressures
Answer» D. two isentropic and two constant pressures

Discussion

18.	An engine operating on the Otto cycle has clearance volume as 10% of the swept volume. If γ = 1.4, the air standard cycle efficiency is
A.	38.3%
B.	39.8%
C.	60.2%
D.	61.7%
Answer» E.

Discussion

19.	An ideal Otto-cycle works between minimum and maximum temperatures of 300 K and 1800 K. What is the compression ratio of the cycle for maximum work output when γ = 1.5 for this ideal gas?
A.	5
B.	6
C.	7
D.	8
Answer» C. 7

Discussion

20.	An I.C engine having 6 cylinders, works on Otto-cycle. It has a bore of 20 cm and a stroke of 40 cm. If the clearance volume is 9000 cm3, the compression ratio is:
A.	10.03
B.	8.53
C.	9.38
D.	7.33
Answer» D. 7.33

Discussion

21.	A heat engine works on dual cycle. It contains:
A.	two adiabatic, two isothermal and one isobaric processes
B.	two isentropic, two isochoric, and one isobaric processes
C.	two isentropic, two isothermal and one isobaric processes
D.	two adiabatic, two isochoric and one isobaric processes
Answer» C. two isentropic, two isothermal and one isobaric processes

Discussion

22.	Otto cycle consist of following four processes
A.	Two isothermals and two isentropic
B.	Two isentropic and two constant volumes
C.	Two isentropic, one constant and one constant pressure
D.	Two isentropic and two constant pressures
Answer» C. Two isentropic, one constant and one constant pressure

Discussion

23.	Match List – I (Details of process of the cycle) with List – II (Name of the cycle) and select correct answer using the codes given below the lists:List – IA. Two isothermals and two adiabaticsB. Two isothermals and two constant volumesC. Two adiabatics and two constant volumesD. Two adiabatics and two constant pressuresList – II1. Otto2. Joule3. Carnot4. Stirling
A.	A – 3, B – 4, C – 1, D - 2
B.	A – 4, B – 3, C – 2, D - 1
C.	A – 4, B – 3, C – 1, D - 2
D.	A – 3, B – 4, C – 2, D - 1
Answer» B. A – 4, B – 3, C – 2, D - 1

Discussion

24.	Consider’ the following factors :Diesel engine knock can be reduced by1. Engine speed2. Compression ratio.3. Degree of supercharge4. Injection advanceWhich of the statements is/are true?
A.	1, 2 and 3 only
B.	2 and 3 only
C.	1, 3 and 4 only
D.	2 only
Answer» B. 2 and 3 only

Discussion

25.	A high-speed diesel engine theoretically operates on ________?
A.	constant pressure cycle
B.	constant volume cycle
C.	constant temperature cycle
D.	mixed cycle of constant pressure and constant volume
Answer» E.

Discussion

26.	In an Otto cycle, the compression ratio is 9:1 and the pressure and temperature at the beginning of the compression process are 100 kPa and 10°C. The heat addition by combustion gives the highest temperature as 2500 K. Specific heat added by combustion is:
A.	0.762 MJ/kg
B.	1.305 MJ/kg
C.	0.286 MJ/kg
D.	1.048 MJ/kg
Answer» C. 0.286 MJ/kg

Discussion

27.	A mass of 1 kg of air at 27°C and 0.98 atm is taken through a diesel cycle. If the compression ratio of the engine is 16, calculate the temperature of the air after compression? (for calculation, take the ratio of specific heats of air as 1.5)
A.	1200 deg C
B.	1473 deg C
C.	927 deg C
D.	768 deg C
Answer» D. 768 deg C

Discussion

28.	In SI engines for higher thermal efficiency
A.	Compression ratio should be high
B.	Heat liberation during combustion should be maximum
C.	Surface to volume ratio should be high
D.	Long flame travel distance
Answer» B. Heat liberation during combustion should be maximum

Discussion

29.	Consider the following statements pertaining to supercharging of engines:1. The power output for a given engine increases2. The loss of power due to altitude is compensated3. The increase in supercharging pressure decreases the tendency to detonate in spark ignition engines4. The mechanical efficiency of supercharged engines is quite high compared to naturally aspirated enginesWhich of the above statements are correct?
A.	1 and 3
B.	3 and 2
C.	2 and 3
D.	1 and 2
Answer» E.

Discussion

30.	A car has four-stroke in line diesel engine whose compression ratio is 21 : 1 and expansion ratio is 10 : 1. What is the cut off ratio ?
A.	3.2
B.	2.1
C.	210
D.	2.8
Answer» C. 210

Discussion

31.	Consider the following statements regarding supercharging of Diesel engines:1) The mechanical efficiency of a supercharged diesel engine is slightly better than that of the naturally aspirated engine.2) There is a reduction in smoke in the case of a supercharged engine in the overload operation.3) Increased valve overlap is used in the supercharged engine.Which of the above statements are correct?
A.	1, 2 and 3
B.	1 and 2 only
C.	1 and 3 only
D.	2 and 3 only
Answer» B. 1 and 2 only

Discussion

32.	An air standard Otto cycle consists of ______.
A.	Constant pressure heat rejection
B.	Constant volume combustion
C.	Isothermal heat addition
D.	Combustion process partly at constant volume and partly at constant pressure
Answer» C. Isothermal heat addition

Discussion

33.	If Tmax and Tmin be the maximum and minimum temperatures in an Otto cycle, then for the ideal conditions, the temperature after compression should be
A.	\(\dfrac{T_{max} + T_{min}}{2}\)
B.	\(\sqrt{\dfrac{T_{max}}{T_{min}}}\)
C.	\(\sqrt{T_{max}\times T_{min}}\)
D.	\(T_{min} + \dfrac{T_{max}-T_{min}}{2}\)
Answer» D. \(T_{min} + \dfrac{T_{max}-T_{min}}{2}\)

Discussion

34.	Cp and Cv for working fluid in a diesel cycle are 1 kJ/kgK and 0.718 kJ/kgK respectively. Temperatures at the beginning and the end of the heat addition process are 1473 K and 1723 K respectively. The heat added is:
A.	179.5 kJ/kg
B.	250 kJ/kg
C.	420 kJ/s
D.	430.75 kJ/kg
Answer» C. 420 kJ/s

Discussion

35.	A diesel engine has a compression ratio of 14 and cut-off takes place at 6% of the stroke. The air standard efficiency will be
A.	74.5%
B.	60.5%
C.	52.5%
D.	44.5%
Answer» C. 52.5%

Discussion

36.	In an Otto cycle, how does heat addition takes place?
A.	Irreversibly at constant pressure
B.	Irreversibly at constant volume
C.	Reversibly at constant pressure
D.	Reversibly at constant volume
Answer» E.

Discussion

37.	Four internally reversible processes like :1. 1 - 2 isentropic compression2. 2 - 3 constant volume heat addition3. 3 - 4 isentropic expansion4. 4 - 1 constant volume heat rejectionThis ideal cycle is called a cycle.
A.	Diesel
B.	Dual
C.	Otto
D.	None of these
Answer» D. None of these

Discussion

38.	A diesel engine is usually more efficient than a spark ignition engine because
A.	Diesel being heavier hydrocarbon, releases 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 SI engine
D.	Self-ignition temperature of diesel is higher than that of gasoline
Answer» D. Self-ignition temperature of diesel is higher than that of gasoline

Discussion

39.	An ideal cycle is shown in the figure below. Its thermal efficiency is given by
A.	\(\frac{{\left( {\frac{{{V_3} - 1}}{{{V_1}}}} \right)}}{{\left( {\frac{{{p_2}}}{{{p_1}}} - 1} \right)}}\)
B.	\(1 - \frac{1}{\gamma }\frac{{\left( {\frac{{{v_3} - 1}}{{{V_1}}}} \right)}}{{\left( {\frac{{{p_2}}}{{{p_1}}} - 1} \right)}}\)
C.	\(1 - \gamma \frac{{\left( {{V_3} - {V_1}} \right)}}{{\left( {{p_2} - {p_1}} \right)}}\frac{{{p_1}}}{{{V_1}}}\)
D.	\(1 - \frac{1}{\gamma }\frac{{\left( {{p_2} - {p_1}} \right)}}{{\left( {{V_3} - {V_1}} \right)}}\frac{{{V_1}}}{{{p_1}}}\)
Answer» D. \(1 - \frac{1}{\gamma }\frac{{\left( {{p_2} - {p_1}} \right)}}{{\left( {{V_3} - {V_1}} \right)}}\frac{{{V_1}}}{{{p_1}}}\)

Discussion

40.	For the same maximum pressure and peak temperature, which cycle will be most efficient?
A.	Diesel
B.	Dual combustion
C.	Otto
D.	None of the above
Answer» B. Dual combustion

Discussion

41.	In an air-standard Otto cycle, the compression ratio is 10. The condition at the beginning of the compression process is 100 kPa and 27 °C. Heat added at constant volume is 1500 kJ/kg, while 700 kJ/kg of heat is rejected during the other constant volume process in the cycle. The specific gas constant for air is 0.287 kJ/kg-K. The mean effective pressure (in kPa) of the cycle is:
A.	103
B.	310
C.	515
D.	1032
Answer» E.

Discussion

42.	A 4-stroke 4-cylinder reciprocating engine has cylinder diameter of 4 cm, stroke length of 7 cm and clearance volume 2 cm3. The engine capacity in cc is:
A.	110
B.	252
C.	400
D.	352
Answer» E.

Discussion

43.	All diesel engines except slow speed engines use which cycles?
A.	Diesel
B.	Otto
C.	Joule
D.	Mixed dual
Answer» E.

Discussion

44.	Lower calorific value of Diesel is about _______.
A.	45,000 kJ/kg
B.	55,000 kJ/kg
C.	35,000 kJ/kg
D.	None of these
Answer» B. 55,000 kJ/kg

Discussion

45.	Consider the following statements:1. The only practical way of improving efficiency of Otto cycle is to increase the compression ratio of an internal combustion enigne2. Ericsson cycle needs heat transfer in all the processes3. Ericsson and Stirling cycles employ regenerative heat exchangers for reversible heat transfer4. Atkinson cycle has a greater specific work than a comparable Otto cycle engineWhich of the above statements are correct?
A.	1, 2, 3 and 4
B.	1, 2 and 4 only
C.	2, 3 and 4 only
D.	1, 2 and 3 only
Answer» B. 1, 2 and 4 only

Discussion

46.	In CI engines, the combustion is:
A.	heterogeneous
B.	very rich
C.	homogeneous
D.	chemically correct
Answer» B. very rich

Discussion

47.	If Otto cycle and diesel cycle work on same compression ration and heat supplied during cycle. Which cycle is more efficient?
A.	Otto Cycle
B.	Diesel cycle
C.	Both
D.	Can’t say
Answer» B. Diesel cycle

Discussion

48.	Compression ratio of an internal combustion engine is defined as _______.[VS = Swept volume, VC = Clearance volume]
A.	\(\frac{{{V_c} + {V_s}}}{{{V_s}}}\)
B.	\(\frac{{{V_c}}}{{{V_s} + {V_c}}}\)
C.	\(\frac{{{V_c} + {V_s}}}{{{V_c}}}\)
D.	\(\frac{{{V_S}}}{{{V_c}}}\)
Answer» D. \(\frac{{{V_S}}}{{{V_c}}}\)

Discussion

49.	If Otto cycle and diesel cycle work on same compression ratio and heat supplied during the cycle. Which cycle is more efficient?
A.	Otto Cycle
B.	Diesel cycle
C.	Both
D.	Depends on Heat rejection
E.	Can’t say
Answer» B. Diesel cycle

Discussion

50.	For the same compression ratio, the efficiency of an air standard Otto cycle is
A.	More than the efficiency of an air standard Diesel cycle
B.	Less than the efficiency of an air standard diesel cycle
C.	Equal to the efficiency of an air standard Diesel cycle
D.	None of the above
Answer» B. Less than the efficiency of an air standard diesel cycle

Discussion

Explore topic-wise MCQs in Mechanical Engineering.

For the same heat input and compression ratio, the most efficient cycle is

In an Ideal Otto cycle the air standard efficiency is 56.5%. if the heat added during the constant volume process is 1000 kJ/kg, determine the work done.

In an Otto cycle, the compression ratio is 9 : 1 and the pressure and temperature at the beginning of the compression process are 100 kPa and 10°C. The heat addition by combustion gives the highest temperature as 2500 K.Thermal efficiency of the cycle is:

An Otto cycle has a compression ratio of 8. If 250 kJ of work is extracted from the cycle, the heat rejected by the cycle is

In an Otto cycle, the compression ratio is 9 : 1, and the pressure and temperature at the beginning of the compression process are 100 kPa and 10° C respectively. The heat addition by combustion gives the highest temperature as 2500 K. The highest cycle pressure is:

An otto cycle has a compression ratio of 9. If 1000 kJ of work is extracted from the cycle, the heat rejected by the cycle is (take γ = 1.5)

In air standard cycle analysis of IC engines, which of the following statements is correct?

In an Otto cycle, air is compressed from 3 litres to 2.4 litres from a starting pressure of 1.5 kg/cm2. The net output per cycle is 400 kJ. What is the mean effective pressure (MPa) of the cycle?

For same compression ratio and heat addition, the efficiency of otto, diesel and dual cycle may compared as

An I.C engine works with a compression ratio of 16. If cut-off happens at 8% of the stroke, then the cut-off ratio of this engine is:

An air standard Otto cycle has volumetric compression ratio of 6, the lowest cycle pressure of 0.1 MPa and operates between temperature limits of 27°C and 1569°C. what is the temperature after isentropic expansion if ratio of specific heats is 1.4?

A four-stroke petrol engine theoretically operates on:

For given compression ratio in the otto cycle, which of the following will give the highest efficiency?

Otto cycle of a car engine consists of:

Diesel cycle consists of which four processes?

An engine operating on the Otto cycle has clearance volume as 10% of the swept volume. If γ = 1.4, the air standard cycle efficiency is

An ideal Otto-cycle works between minimum and maximum temperatures of 300 K and 1800 K. What is the compression ratio of the cycle for maximum work output when γ = 1.5 for this ideal gas?

An I.C engine having 6 cylinders, works on Otto-cycle. It has a bore of 20 cm and a stroke of 40 cm. If the clearance volume is 9000 cm3, the compression ratio is:

A heat engine works on dual cycle. It contains:

Otto cycle consist of following four processes

Consider’ the following factors :Diesel engine knock can be reduced by1. Engine speed2. Compression ratio.3. Degree of supercharge4. Injection advanceWhich of the statements is/are true?

A high-speed diesel engine theoretically operates on ________?

In an Otto cycle, the compression ratio is 9:1 and the pressure and temperature at the beginning of the compression process are 100 kPa and 10°C. The heat addition by combustion gives the highest temperature as 2500 K. Specific heat added by combustion is:

A mass of 1 kg of air at 27°C and 0.98 atm is taken through a diesel cycle. If the compression ratio of the engine is 16, calculate the temperature of the air after compression? (for calculation, take the ratio of specific heats of air as 1.5)

In SI engines for higher thermal efficiency

A car has four-stroke in line diesel engine whose compression ratio is 21 : 1 and expansion ratio is 10 : 1. What is the cut off ratio ?

An air standard Otto cycle consists of ______.

If Tmax and Tmin be the maximum and minimum temperatures in an Otto cycle, then for the ideal conditions, the temperature after compression should be

Cp and Cv for working fluid in a diesel cycle are 1 kJ/kgK and 0.718 kJ/kgK respectively. Temperatures at the beginning and the end of the heat addition process are 1473 K and 1723 K respectively. The heat added is:

A diesel engine has a compression ratio of 14 and cut-off takes place at 6% of the stroke. The air standard efficiency will be

In an Otto cycle, how does heat addition takes place?

Four internally reversible processes like :1. 1 - 2 isentropic compression2. 2 - 3 constant volume heat addition3. 3 - 4 isentropic expansion4. 4 - 1 constant volume heat rejectionThis ideal cycle is called a cycle.

A diesel engine is usually more efficient than a spark ignition engine because

An ideal cycle is shown in the figure below. Its thermal efficiency is given by

For the same maximum pressure and peak temperature, which cycle will be most efficient?

A 4-stroke 4-cylinder reciprocating engine has cylinder diameter of 4 cm, stroke length of 7 cm and clearance volume 2 cm3. The engine capacity in cc is:

All diesel engines except slow speed engines use which cycles?

Lower calorific value of Diesel is about _______.

In CI engines, the combustion is:

If Otto cycle and diesel cycle work on same compression ration and heat supplied during cycle. Which cycle is more efficient?

Compression ratio of an internal combustion engine is defined as _______.[VS = Swept volume, VC = Clearance volume]

If Otto cycle and diesel cycle work on same compression ratio and heat supplied during the cycle. Which cycle is more efficient?

For the same compression ratio, the efficiency of an air standard Otto cycle is