Chapter 1 Introduction of I. C. Engine

Faculty of Degree Engineering-083 Department of Mechanical Engineering – 19

INTERNAL COMBUSTION ENGINES Prepared by Asst. Prof. P J Gajera

Chapter 1 Introduction of I. C. Engine

1. Advantage of reciprocating IC engines over steam turbine is

(a) Mechanical simplicity

(b) Improved plant efficiency

(e) Lower average temperature

(d) all of the above

Ans: d

2. The intake charge in a diesel engine consists of

(a) air alone

(b) air + lubricating oil

(c) air + fuel

(d) air + fuel + lubricating oil

Ans: a

3. Engines of different cylinder dimensions, power and speed can be compared on the basis of

(a) Maximum pressure

(b) Fuel consumption

(c) mean effective pressure

(d) unit power

Ans: c

4. Disadvantages of reciprocating IC engine are

(a) vibration

(b) use of fossil fuels



(c) balancing problems


Ans: d

5. Gudgeon pin forms the link between

(a) piston and big end of connecting rod

(b) piston and small end of connecting rod

(c) connecting rod and crank

(d) big end and small end

Ans: b

6. An IC engine gives an output of 3 kW when the input is 10,000 J/s. The thermal efficiency of

the engine is

(a) 33.3%

(b) 30%

(c) 60%

(a) 66.6%

Ans: b

7. In a four-stroke IC engine cam shaft rotates at

(a) same speed as crankshaft

(b) twice the speed of crankshaft

(c) halt the speed of crankshaft

(d) none of the above

Ans: c



8. Thermal efficiency of CI engine is higher than that of SI engine due

(a) light weight

(b) higher compression ratio

(c) constant pressure heat addition


Ans: b

9. SI engines are of

(a) light weight

(b) high speed

(c) homogeneous change of fuel and oil


Ans: d

10. Compression ratio in diesel engines is of the order of

(a)5-7

(b) 7 -10

(c)10 – 12

(d) 14-20

Ans: d

11. In a reciprocating engine with a cylinder diameter of D and stroke of the cylinder volume is



Ans: c

12. Main advantage of a two-stroke engine over four-stroke engine is

(a) more uniform torque on the crankshaft

(b) more power output for the cylinder of same dimensions

(c) absence of valves


Ans: d

13. Engines used for ships are normally

(a) four-stroke Sl engines of very high power

(b) two-stroke CI engines of very high power

(c) four-stroke Cl engines of high speed

(d) two-stroke SI engines of high power

Ans: b

14.If L is the stroke and N is the rpm, mean piston speed of two-stroke engine

(a) LN

(b) LN/2



(c) 2LN


Ans: c

15. Equivalence ratio is

(d) None of the above the above

Ans: d

16. The volumetric efficiency of the SI engine is comparatively

(a) lower than CI engine

(b) higher than CI engine

(c) will be same as CI engine


Ans: a

17. The range of volumetric efficiency of a

(a) 65- 75%

(b) 75 - 85%

(c) 85 - 90%

(d) 90 - 95%



Ans: c

18. Relative efficiency is the ratio of

Ans: b

19. Brake specific fuel consumption is defined as

(a) fuel consumption per hour

(b) fuel consumption per km

(c) fuel consumption per BP

(d) fuel consumption per brake power hour

Ans: d

20. Engine can be fired with

(a) solid fuel

(b) liquid fuel

(c) gaseous fuel

(d) any of the above fuels

Ans: d



21. A two-stroke engine can be identified by

(a) cooling system

(b) lubrication system

(c) absence of valves

(d) piston size

Ans: c

22. Advantage of two-stroke engine is

(a) more uniform torque

(b) lighter flywheel

(c) no valves


Ans: d

23. Charge pressure at the inlet port of a two-stroke engine is

(a) 20 bar

(b) vacuum

(c) atmospheric

(d) higher than atmospheric

Ans: d

24. The most perfect method of scavenging is

(a) cross scavenging

(b) uniflow scavenging

(c) loop scavenging



(d) reverse flow scavenging

Ans: b

25. Two-stroke SI engines suffer from

(a) fuel loss

(b) idling difficulty

(c) both (a) and (b) together


Ans: a

26. At the same speed two-stroke engine of the same size as a four-stroke engine will develop

(a) same power

(b) half the power

(c) twice the power

(d) four times the power

Ans: c

27. Two wheelers without deflector type piston use

a) loop scavenging

(b) unifow scavenging

(c) reverse flow scavenging

(d) cross scavenging

Ans: d

28. Crankcase scavenged engines have delivery ratio of

(a) greater than 1



(b) less than 1

(c) equal to 1


Ans: c

29. The working cycle in case of four stroke engine is completed in following number of

revolutions of crankshaft

(a) 1/2

(b) 1

(c) 2

(d) 4

(e) 8.

Ans: c

30. In a diesel engine, the fuel is ignited by

(a) spark

(b) injected fuel

(c) heat resulting from compressing air that is supplied for combustion

(d) ignitor

(e) combustion chamber.

Ans: c

31. Scavenging air in diesel engine means

(a) air used for combustion sent under pres-sure

(b) forced air for cooling cylinder



(c) burnt air containing products of com-bastion

(d) air used for forcing burnt gases out of engine's cylinder during the exhaust period

(e) air fuel mixture.

Ans: d

32. Does the supply of scavenging air at a density greater than that of atmosphere mean engine

is supercharged?

(a) yes

(b) no

(c) to some extent

(d) unpredictable

(e) depends on other factors.

Ans: b

33. 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

(e) cycle efficiency.

Ans: c

34. 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.

Ans: a

Chapter 2 Fuel Air Cycles and Actual Cycles

1. A perfect engine works on the Carnot cycle between 727 °C and 227°C. The efficiency of the

engine is

(a) 0.5

(b) 0.75

(c) 1

(d) 0.25

Ans: a

2. The air standard Otto cycle consists of

(a) two constant volume and two isentropic processes

(b) two constant pressure and two isentropic processes

(c) two constant pressure and two constant volume processes


Ans: a

3. In air standard Diesel cycle at fixed r and fixed n

(a) ƞthermal increases with increase in heat addition and cut-off ratio

(b) ƞthermal decreases with increase in heat addition and cut-off ratio



(c) ƞthermal Remains the same with increase in heat addition and cut-off ratio


Ans: b

4. Mean effective pressure of Otto cycle is

(a) inversely proportional to pressure ratio

(b) directly proportional to pressure ratio

(c) does not depend on pressure ratio

(d) proportional to square root of pressure ratio

Ans: b

5. For a given compression ratio the work output of Otto cycle is

(a) increases with Increase in r

(b) decreases with increase in r

(c) is not affected


Ans: a

6. For a given value of r, efficiency of Otto cycle

(a) decreases with compression ratio

(b) increases with compression ratio

(c) is not affected


Ans: b



7. For dual combustion cycle for fixed value of heat addition and compression ratio

(a) mep wil be greater with increase in rp, and decrease in rc

(b) mep will be greater with decrease in rp and decrease in rc

(c) mep remain the same with increase in rp and decrease in rc


Ans: a

8. The normal range of, compression ratio for Otto cycle is

(a) 6 to 10

(b) 2 to 4

(c) >10


Ans: a

9. The normal range of compression ratio for Diesel cycle is

(a) 4 to 6

(b) 6 to 8

(c) 15 to 20

(d) >25

Ans: c

10. For the same compression ratio and heat addition

(a) ƞOtto > ƞDiesel > ƞDual

(b) ƞDiesel > ƞOtto > ƞDual



(c) ƞOtto> ƞDual > ƞDiesel

(d) ƞDual> ƞDiesel > ƞOtto

Ans: c

11. for the same compression ratio and heat rejection,

(a) ƞOtto> ƞDual > ƞDiesel

(b) ƞDiesel > ƞDual > ƞOtto

(c) ƞDual> ƞDiesel > ƞOtto

(d) ƞDual> ƞOtto> ƞDiesel

Ans: a

12. When the engines are built to withstand the sane thermal and mechanical stresses

(a) ƞDiesel > ƞDual > ƞOtto

(b) ƞDual> ƞDiesel > ƞOtto

(c) ƞOtto> ƞDual > ƞDiesel

(d) ƞOtto> ƞDiesel > ƞDual

Ans: a

13. For the same peak pressure and heat input

(a) ƞOtto > ƞDual > ƞDiesel

(b) ƞOtto > ƞDiesel > ƞDual

(c) ƞDiesel > ƞDual > ƞOtto



(d) ƞDiesel > ƞOtto > ƞDual

Ans: c

14. For the same peak pressure and work output

(a) ƞOtto > ƞDual > ƞDiesel

(b) ƞOtto > ƞDiesel > ƞDual

(c) ƞDiesel > ƞOtto > ƞDual

(d) ƞDiesel > ƞDual > ƞOtto

Ans: d

15. Brayton cycle is used in

(a) Ramjet engines

(b) gas turbines

(c) pulse jet engines

(d) Cl engines

Ans: b

16. The actual efficiency of a good engine is about _______of the estimated fuel-air cycle

efficiency.

(a) 100%

(b) 85%

(c) 50%

(d) 25%

Ans: b



17. With dissociation peak temperature is obtained

(a) at the stoichiometric air-fuel ratio

(b) when the mixture is slightly lean

(c) when the mixture is slightly rich


Ans: c

18. With dissociation the exhaust gas temperature

(a) decreases

(b) increases

(c) no effect

(d) increases upto certain air-fuel ratio and then decreases

Ans: a

19. Fuel-air ratio affects maximum power output of the engine due to

(a) higher specific heats

(b) chemical equilibrium losses

(c) both (a) and (b)


Ans: c

20. Mean effective pressure at a given compression ratio is maximum when the air-fuel ratio is

(a) higher than stoichiometric

(b) lower than stoichiometric

(c)equal to stoichionetric




Ans: b

21. For a compressor process with variable specific heat the peak temperature and pressure are

_______compared to constant specific heat

(a)lower

(b)higher

(c) no effect


Ans: a

22. Dissociation can be considered as

(a) disintegration of combustion products at high temperature

(b) reverse process of combustion

(c) heat absorption process


Ans: d

23. Time loss factor in actual cycle is due to

(a) Progressive combustion

(b) heat loss through cylinder walls

(c) gas leakage

(d) friction

Ans: a

24. The major loss in a SI engine is due to



(a) exhaust blow down

(b) pumping

(c) incomplete combustion

(d) variation in specific heat and chemical equilibrium

Ans: d

25. Fuel-air cycle efficiency is less than air-standard cycle efficiency by an amount equal to

(a) pumping loss

(b) friction loss

(c) loss due to specific heat variation and chemical equilibrium

(d) exhaust blow down loss

Ans: c

26. The major loss in a CI engine is

(a) direct heat loss

(b) loss due to incomplete combustion

(c) rubbing friction loss

(d) pumping loss

Ans: b

27. The ratio of the actual efficiency and the fuel-air cycle efficiency for CI engines is about

(a) 0.2-0.3

(b) 0.5-0.6

(c) 1.0

(d) 0.6-0.8



Ans: d

28. In an actual SI engine the pumping loss with respect to speed

(a) decreases

(b) Increases

(c) remains constant

(d) nothing to do with speed

Ans: b

29. The volumetric efficiency is affected by

(a) the exhaust gas in the clearance volume

(b) the design of intake and exhaust valve

(c) valve timing


Ans:d

30. The air standard efficiency of an Otto cycle compared to diesel cycle for the given

compression ratio is

(a) same

(b) less

(c) more

(d) more or less depending on power rating

Ans: c

31. 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°.

Ans: c

32. In a typical medium speed, 4-stroke cycle diesel engine

(a) fuel injection 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 dead center

(d) may start and end anywhere

Ans: a

Chapter-3 Combustion

1. The amount of heat liberated by complete combustion of unit quantity of fuel is known as

________

(a) Agitation

(b) Combustion

(c) Calorific value

(d) Thermogenesis

Ans: c

2. The calorific value of gaseous fuels is expressed in terms of

(a) kcal

(b) B. kcal/kg

(c) C. kcal/m²

(d) D. kcal/m3

Ans: D

3. What is the significance of calorific value?



(a) Helps in deciding which fuel is good

(b) Helps in locating fuel

(c) Helps in deciding ignition temperature

(d) Helps in deciding fire point

Ans: a

4. Which gas has the highest calorific value among given option?

(a) Oxygen

(b) Helium

(c) Hydrogen

d) Nitrogen

Ans: c

5. Which calorimeter is used to find calorific values of solid and liquid fuels?

(a) Boy’s calorimeter

(b) Bomb calorimeter

(c) Junker’s calorimeter

(d) Calvet-type calorimeter

Ans: b

6. Which calorimeter is used to find calorific values of gaseous fuels?

(a) Bomb calorimeter

(b) Junker calorimeter

(c) Adiabatic calorimeter

(d) Isothermal titration calorimeter

Ans: b

7. What is the factor on which, difference between the two heating values of fuel depends on?

(a) Physical properties

(b) Reactants

(c) Chemical composition



(d) Products

Ans: c

8. The Bomb calorimeter is used to determine the calorific value of:

(a) solids and liquid fuels

(b) solid and gaseous fuels

(c) liquid fuels that can be easily vaporized

(d) solid fuels only

Ans: a

9. If the intake air temperature of I.C. engine increases, its efficiency will

(a) increase

(b) decrease

(c) remain same

(d) unpredictable

(e) depend on other factors.

Ans: b

10. 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.

Ans: a

11. An engine indicator is used to determine the following

(a) speed

(b) temperature

(c) volume of cylinder

(d) m.e.p. and I.H.P.



(e) BHP.

Ans: d

12. 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

Ans: b

13.Combustion in compression ignition engines is

(a) homogeneous

(b) heterogeneous


(d) laminar

(e) turbulent.

Ans: b

14.The air requirement of a petrol engine during starting compared to theoretical required for

complete combustion is

(a) more

(b) loss

(c) same

(d) may be more or less depending on engine capacity

(e) unpredictable.

Ans: b

15. Diesel fuel, compared to petrol is

(a) less difficult to ignite

(b) just about the same difficult to ignite

(c) more difficult to ignite



(d) highly ignitable

(e) none of the above.

Ans: c

16.When crude oil is heated, then which of the following hydrocarbon is given off first.

(a) kerosene

(b) gasoline

(c) paraffin

(d) diesel

(e) natural gas.

Ans: e

17. The rating of a diesel engine, with increase in air-intlet temperature, will

(a) increase linearly

(b) decrease linearly

(c) increase parabolically

(d) decrease parabolically

(e) first decrease linearly and then increase parabolically.

Ans: b

18. A 75 cc engine has following parameter as 75 cc

(a) fuel tank capacity

(b) lub oil capacity

(c) swept volume

(d) cylinder volume

(e) clearance volume.

Ans: c

19.A heat engine utilises the

(a) calorific value of oil

(b) low heat value of



(c) high heat value of oil

(d) mean heat value of oil


Ans: c

20. Gaseous-fuel guarantees are based on

(a) calorific value of oil

(b) low heat value of oil

(c) high heat value of oil

(d) mean heat value of oil


Ans: b

21. Fuel consumption of diesel engines is not guaranteed at one quarter load because at such

low loads

(a) the friction is high

(b) the friction is unpredictable

(c) the small difference in cooling water temperature or in internal friction has a

disproportionate effect

(d) the engine is rarely operated


Ans: c

22. Polymerisation is a chemical process in which molecules of a compound become

(a) larger

(b) slowed down

(c) smaller

(d) liquid

(e) gaseous.

Ans: a



23. Which of the following is the lightest and most volatile liquid fuel

(a) diesel

(b) kerosene

(c) fuel oil

(d) gasoline

(e) lub oil.

Ans: d

24. 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

(e) 20 : 1.

Ans: d

25. Air fuel ratio for idling speed of a petrol engine is approximately

(a) 1 : 1

(b) 5 : 1

(c) 10:1

(d) 15 : 1

(e) 20 : 1.

Ans: c

26. Air fuel ratio at which a petrol engine can not work is

(a) 8 : 1

(b) 10 : 1

(c) 15 : 1

(d) 20 : 1 and less

(e) will work at all ratios.



Ans: d

27. For maximum power generation, the air fuel ratio for a petrol engine for vehicles, is of the

order of

(a) 9 : 1

(b) 12 : 1

(c) 15 : 1

(d) 18 : 1

(e) 20: 1.

Ans: b

Chapter-4 Fuels and its supply system for SI and CI engine

1. Advantage of gaseous fuel is that

(a) it can be stored easily

(b) it can mix easily with air

(c) it can displace more air from the engine


Ans: b

2. Paraffins are in general represented by

(a) CnHn

(b) CnH2n

(c) CnH2n+2

(d) CnH2n-6

Ans: c

3. Paraffins have molecular structure of

(a) chain saturated

(b) chain unsaturated

(c) ring saturated



(d) ring unsaturated

Ans: a

4. Olefins are represented by the formula

(a) CnH2n

(6) CnH2n+2

(c) CnH2n-4

(d) CnH2n-6

Ans: a

5. Hydrocarbons are decomposed into smaller hydrocarbons by

(a) reforming

(b) refining

(c) cracking

(d) polymerization

Ans: c

6. The molecular structure of the straight-run gasoline is changed by

(a) cracking

(b) reforming

(c) reining

(d) boiling

Ans: b

7. For SI engines fuels most preferred are

(a) aromatics

(b) parafins

(c) olefins

(d) napthenes

Ans: a

8. For CI engine fuels most preferred are



(a) napthenes

(b) paraffins

(c) olefins

(d) aromatics

Ans: b

9. Octane number of iso-octane is

(a) 0

(b) 30

(c) 60

(d) 100

Ans: d

10. Ignition quality of diesel fuel is indicated by its

a) octane number

(b) cetane number

(c) fash point

(d) fire point

Ans: b

11. Flash point of fuel oil is

(a) minimum temperature to which1 oil is heated in order to give off inflammable vapours in

Sufficient quantity to ignite momentarily when brought in contact with a flame

(b) temperature at which it solidifies or congeals

(c) temperature at which it catches fire without external aid

(d) indicated by 90% distillation temperature, i.e. when 90% of sample oil has distilled off


Ans: a

12. Gasohol is a mixture of

(a) 90% ethanol + 10% gasoline



(b) 10% ethanol +90% gasoline

(c) 40% ethanol + 60% gasoline

(d) 50% ethanol +50% gasoline

Ans: b

13. Stoichiometric air-fuel ratio of petrol is roughly

(a) 50:1

(b) 25:1

(c) 15:1

(d) 1:1

Ans: c

14. Venturi in the carburetor results in

(a) decrease of air velocity

(b) increase of air velocity

(c) decrease of fuel flow

(d) increase of manifold vacuum

Ans: b

15. The choke is closed when the engine is

(a) accelerating

(b) hot

(c) cold

(d) idling

Ans: c

16. Lean air mixture is required during

(a) idling

(b) starting

(c) accelerating

(d) cruising



Ans: d

17. The limits of air-fuel for SI engine are

(a) 8/1 to 18/1

(b) 8/1 to 50/1

(c) 25/1 to 50/1

(d) 50/1 to 100/1

Ans: a

18. For maximum thermal efficiency, the fuel-air mixture in SI engines should be

(a) lean

(b) rich

(c) stoichiometric

(d) may be rich or lean

Ans: a

19. During starting petrol engines require

(a) stoichiometric mixture

(b) lean mixture

(c) rich mixture

(d) any air-fuel ratio is alright

Ans: c

20. Economizer is used to provide enriched mixture during

(a) Starling

(b) idling

(c) cruising

(d) full throttle operation

Ans: d

21. When the throttle is suddenly opened, the mixture of the simple carburetor tends to

become



(a) rich

(b)lean

(c )stoichiometric

(d) not affected

Ans: b

22. Precise petrol injection system is

(a) direct injection

(b) sequential injection

(c)throttle body injection

(d) port injection

Ans: c

23. The choke in an automobile meant for supplying

(a) lean mixture

(b) rich mixture

(c) stoichiometric mixture

(d) weak mixture

Ans: b

24. Modern carburetors provide the correct quality of air-fuel mixture during

(a) starting

(b) idling

(c) cruising

(d) all conditions

Ans: d

25. A simple carburetor supplies rich mixture during

(a) starting

(b) idling

(c) cruising



(d) accelerating

Ans: d

26. Fuel injector is used for

(a) gas engines

(b) CI engines

(c) SI engines


Ans: b

27. Advantage of air injection system is

(a) cheaper fuels can be used

(b) mep is high

(c) fine atomization and distribution of the fuel


Ans: d

28. Commonly used injection system in automobiles is

(a) air injection

(b) solid injection

(c) combination of (a) and (b)


Ans: b

29. Fuel injection pressure in solid injection system is around

(a) <10 bar

(b) 10-20 bar

(c) 30-50 bar

(d) 200-250 bar

Ans: d

30. Fuel filters do not use generally



(a) oil

(b) paper

(c) cloth

(d) felt

Ans: b

31. Fuel is injected in a four-stroke CI engine

(a) at the end of suction stroke

(b) at the end of expansion stroke

(c) at the end of compression stroke

(d) at the end of exhaust stroke

Ans: c

32. Injection system in which the pump and the injector nozzle is combined in one housing is

known as

(a) common rail system

(b) distributor system

(c) unit injector system

(d) individual pump and nozzle system

Ans: c

33. Main advantage of pintaux nozzle is

(a) better cold starting performance

(b) ability to distribute the fuel

(c) good penetration

(d) good atomization

Ans: a

34. the most accurate gasoline injection system is

(a) direct injection

(b) port injection



(c)throttle body injection

(d) manifold injection

Ans: b

35. Advantage of fuel injection in SI engine is

(a) low initial cost

(b) low maintenance requirements

(c) increased volumetric efficiency


Ans: c

36-‘MPFI’ stands for

(a) Multi point fuel injection

(b) Multi port fuel injection

(c) Manifold point fuel injection

(d)Manifold port fuel injection

Ans: a

37. In carburetor, Choke is incorporated

a. Before the venturi

b. After the venturi

c. In the venturi

d. Any of the above

Ans: a

38. The following factors affect the process of carburetion

a. Engine speed

b. The temperature of incoming air

c. The volatility of fuel

d. All of the above

Ans: d



39. In MPFI _____ is used to spray fuel into engine.

(a|) Engine vacuum

(b) Suction pressure of engine

(c) Electric pump

(d) None of the above

Ans: b

40. Multi-point fuel injection system uses

(a) manifold injection

(b) direct injection

(c) port injection

(d) throttle body injection

(e) both (c) and (d)

Ans: Both c & d

41. L-MPFI system uses

(a) port injection

(b) direct injection

(c) manifold injection


Ans: a

42. D-MPFI system uses

(a) port injection

(b) manifold injection

(c) direct injection


Ans: b

43. Common rail injection system uses injection pressures of the order

(a) 100-200 bar



(b) 200-400 bar

(c) 400-600 bar

(a) 1500 bar

Ans: d

44. Continuous injection system usually has

(a) plunger pump

(b) rotary pump

(c) gear pump

(d) vane pump

Ans: b

45. The cold start injector

(a) maintain stoichiometric air-fuel ratio

(b) provides lean air-fuel ratio

(c) gives rich air-fuel ratio

(d) is not used for any of the above functions

Ans: c

46. ECU is an electronic injection system used for

(a) calculating the appropriate injection timing

(b) meeting only certain operating conditions

(c) closing the injection valve only


Ans: a

47. With EFI (ELECTRONIC FUEL INJECTION) of diesel engines

(a) sharp start and stop is not possible

(b) very high injection pressure can be obtained

(c)sudden cylinder cut-off is impossible

(d) diagnostic properties are poor



Ans: b

48. EFI system can achieve

(a) proper injection timing

(b) proper injection quantity

(c) proper injection pressure


Ans: d

49-The following is (are) the modern carburetors used in automobiles

(a) Solex carburetor

(b) Cartex carburetor

(c ) S.U. carburetor

(d) All of the above

Ans: d

50-The first vehicle in India equipped with MPFI system in Indian automobile industry

(a) Tata Indica

(b) Daewoo Matiz

(c ) Maruti Alto

(d) Chevrolet spark

Ans: b

51. 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

Ans: d

52. The specific fuel consumption per BHP hour for diesel engine is approximately



(a) 0.15 kg

(b) 0.2 kg

(c) 0.25 kg

(d) 0.3 kg

(e) 0.35 kg.

Ans: b

53. 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.

Ans: c

54. The air-fuel ratio of the petrol engine is controlled by

(a) fuel pump

(b) governor

(c) injector

(d) carburettor

(e) scavenging.

Ans: d

55. Pour point of fuel oil is the

(a) minimum temperature to which oil is heated in order to give off inflammable vapours in

sufficient quantity to ignite momentarily when brought in contact with a flame

(b) temperature at which it solidifies or congeals

(c) it catches fire without external aid

(d) indicated by 90% distillation temperature i.e., when 90% of sample oil has distilled off

(e) temperature at which it flows easily.



Ans: b

56. A 5 BHP engine running at full load would consume diesel of the order of

(a) 0.3 kg/hr

(b) 1 kg/hr

(c) 3 kg/hr

(d) 5 kg/hr

(e) 10 kg/hr.

Ans: b

Chapter-5 Ignition and Governing system

1. The secondary winding of ignition coil consists of

(a) few turns of fine wire

(b) few turns of thick wire

(c) many turns of fine wire

(d) many turns of thick wire

Ans: c

2. Dwell is the time

(a) for which the points remain closed

(b) for which the points remain open

(c) time during which inlet and exhaust valves are open


Ans: a

3. Dwell period

(a) is directly proportional to engine speed

(b) is inversely proportional to engine speed

(c) does not depend on engine speed

(a) none of the above

Ans: b



4. If the contact breaker gap is small, it results in

(a) advanced timing

(b) increased dwell

(c) rapid burning of the pointer gaps


Ans: c

5. For a four cylinder engine operating at N rpm, the contact breaker must make and break the

circuit

(a) N times

(b) 2N times

(c) N/2 times


Ans: b

6. Contact breaker should be set

(a) just before starting the engine

(b) before adjustment of dwell angle

(c) after adjustment of dwell angle

(d) before setting spark plug gap

Ans: c

7. Dwell meter is used for

(a) setting spark plug gap

(b) contact breaker gap

(c) setting the ignition advance

(d) setting

Ans: b

8. For a four cylinder vertical engine, the commonly used firing order is

(a) 1-2-3-4



(b) 3-4-1-2

(c) 1-3-4-2

(a) 4-3-2-1

Ans: c

9. For engine operating with rich mixtures the optimum spark timing

(a) must be advanced

(b) must be retarded

(c)must be at TDC


Ans: a

10. For peak lead operation, the spark advance

(a) must be decreased

(b) must be increased

(c) need not be altered


Ans: a

11. Ignition timing is adjusted by

(a) tachometer

(b) stroboscopic light

(c) stop watch

(d) accurate clock

Ans: b

12. Vacuum advance mechanism shifts the ignition point under

(a) no load operation

(b) full load operation

(c) part load operation

(d) under sudden acceleration



Ans: c

13. Which of the following statement is wrong?

(a) retarded timing causes exhaust gas temperature to be higher

(b) retarded timing improves fuel economy

(c) retarded timing requires slightly longer throttle opening

(d) retarded timing causes burning of the hydrocarbons in the exhaust

Ans: d

14. Choose the correct statement from the following

(a) maintenance problem in magneto-ignition system is more

(b) magneto ignition system occupies more space

(c) magneto ignition system is used in larger four wheelers

(d) magneto ignition system has poor quality of spark during starting

Ans: d

15. Battery ignition system

(a) occupies more space

(b) has more maintenance problem

(c) is commonly employed in four wheelers


Ans: d

16. Method of governing used in petrol engine is

(a) hit and miss governing.

(b) quality governing

(c) quantity governing

(d) none of above

Ans: c

17. Pick up the false statement

(a) Thermal efficiency of diesel engine i about 34%



(b) Theoretically correct mixture of air am petrol is approximately 15 : 1

(c) High speed compression engines operate on dual combustion cycle

(d) Diesel engines are compression ignition engines

(e) S.I. engines are quality-governed engines.

Ans: e

18. The magneto in an automobile is basically

(c) transformer

(b) d.c. generator

(c) capacitor

(d) magnetic circuit

(e) a.c. generator.

Ans: b

Chapter-6 Supercharging and Turbocharging of I C Engine

1. Supercharging increases the power output of the engine by

(a) increasing the charge temperature

(b) increasing the charge pressure

(c ) increasing the speed of the engine

(d) quantity of fuel admitted

Ans: b

2. The centrifugal type supercharger is preferable only for

(a) low speeds

(b) high speeds

(c) high pressures


Ans: a

3. The advantage of Root's supercharger is

(a) big pressure



(b) minimum maintenance

(c) consumes less power

(d) occupies less space

Ans: b

4. Supercharging air compressor is driven by

(a) exhaust gas turbine

(b) engine itself

(c) separate electrical motor


Ans: b

5. If turbochargers compressor is driven by

(a) exhaust gas turbine

(6) engine itself

c) separate electrical motor


Ans: a

6. Cooling after compression is necessary to

(a) increase the density of air

(b) reduce engine operating temperatures


(d) increase exhaust temperature

Ans: c

7. Volumetric efficiency of supercharged engine is

(a) between 100 - 110%

(b) between 90 - 100%

(c) between 80 - 90%

(d) between 70 - 80%



Ans: a

8. Supercharging is normally done in

(a) racing cars

(b) marine engines

(c)automotive diesel engines


Ans: d

9. Compared to engine driven supercharger the exhaust driven super charger is

(a) easy to handle

(b) supplies more air

(c) utilizes the exhaust energy of the engine

(d) matching with engine is easy

Ans: c

10. Types of supercharger are

(a) reciprocating type

(b) gear type

(c) centrifugal type

(a) none of the above

Ans: c

11. The operation of forcing additional air under pressure in the engine cylinder is known as

(a) scavenging

(b) turbulence

(c) supercharging

(d) pre-ignition

(e) dissociation and carburretion of fuel.

Ans: c

12. Supercharging is essential in



(a) diesel engines

(b) gas turbines

(c) petrol engines

(d) aircraft engines

(e) marine engines.

Ans: d

13. The output of a diesel engine can be increased without increasing the engine revolution or

size

in following way

(a) feeding more fuel

(b) increasing flywheel size

(c) heating incoming air

(d) scavenging

(e) supercharging.

Ans: e

14. 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.

Ans: a

15. Pick up the wrong statement about supercharging

(a) supercharging reduces knocking in diesel engines

(b) there can be limited supercharging in petrol engines because of detonation

(c) supercharging at high altitudes is essential



(d) supercharging results in fuel economy

(e) supercharging is essential in aircraft engines.

Ans: d

16. The reason for supercharging in any engine is to

(a) increase efficiency

(b) increase power

(c) reduce weight and bulk for a given out-put

(d) effect fuel economy


Ans: c

17. For the same power developed in I.C. engines, the cheaper system is

(a) naturally aspirated

(b) supercharged

(c) centrifugal pump

(d) turbo charger


Ans: b

18. Installation of supercharger on a four-cycle diesel engine can result in the following

percentage increase in power

(a) upto 25%

(b) upto 35%

(c) upto 50%

(d) upto 75%

(e) upto 100%.

Ans: e

Chapter-7 Combustion in SI and CI Engines

1. In SI engines maximum flame speed is obtained when the equivalent ratio is between



(a) 1.1 and 1.2

(b) 1.0 and 1.1

(c) 1.2 and 1.3

(d) less than 1

Ans: a

2. In SI engines flame speed increases

(a) with turbulence

(b) with fuel-air ratio



Ans: c

3. with increase in compression ratio flame speed

(a) increases

(b) decreases

(c) remains the same


Ans: a

4. With increase in speed the crank angle required for fame propagation

(a) increases

(b) decreases

(c) not affected


Ans: c

5. Increasing the compression ratio in SI engines the knocking tendency

(a) decreases

(b) increases

(c) not affected




Ans: b

6. Decreasing the cooling water temperature in SI engines the knocking tendency

(a) increases

(b) decreases

(c) not affected


Ans: b

7. Detonation in SI engines occur due to

(a) pre ignition of the charge before the spark

(b) sudden ignition of the charge before the spark

(c) autoignition of the charge after the spark in struck


Ans: c

8. Desirable characteristics of the combustion chamber for SI engines to avoid knock is

(a) small bore

(b) short ratio of fame path to bore

(c) absence of hot surfaces in the last region of the charge


Ans: d

9. In CI engines with increase in compression ratio the delay period

(a) increases

(b) decreases

(c) first increases and then decreases

(d) not affected

Ans: c

10. Knocking takes place in CI engines



(a) at the start of combustion

(b) at the end of combustion

(c) during combustion


Ans: a

11. In CI engines knocking tendency increases with

(a) increase in compression ratio

(b) increasing inlet temperature of air

(c) decrease in compression ratio

(d) increasing coolant water temperature

Ans: c

12. In CI engines by increasing inlet air pressure the knocking tendency

(a) increases

(b) decreases

(c) not affected

(d) first decreases and then increases

Ans: b

13. Open combustion chambers in CI engines require

(a) high injection pressures

(b) accurate metering of fuel by the injection system



Ans: c

14. The advantages of the indirect injection combustion chambers are

(a) low injection pressure

(b) direction of spray is not critical




(d) good cold starting performance

Ans: c

15. In CI engines the delay period is affected by

(a) compression ratio

(b) engine speed

(c) output


Ans: d

16. Crankcase explosion in I.C. engines usually 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.

Ans: a

17. Compression loss in I.C engines occurs duto

(a) leaking piston rings

(b) use of thick head gasket

(c) clogged air-inlet slots

(d) increase in clearance volume caused b bearing-bushing wear


Ans: e

18. 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.

Ans: a

19. The precess of breaking up or a liquid into fine droplets by spraying is called

(a) vaporisation

(b) carburetion

(c) ionisation

(d) injection

(e) atomisation.

Ans: e

20. 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.

Ans: b

21. Which of the following statements is correct?

(a) All the irreversible engines have same efficiency

(b) All the reversible engines have same efficiency

(c) Both Rankine and Caront cycles have same efficiency between same temperature limits

(d) All reversible engines working between same temperature limits have same-efficiency

Ans: d

22. The accumulation of carbon in a cylinder results in increase of

(a) clearance volume

(b) volumetric efficiency

(c) ignition time

(d) effective compression ratio



(e) valve travel time.

Ans: d

23. In diesel engine the diesel fuel injected intc cylinder would burn instantly at about

compressed air temperature of

(a) 250°C

(b) 500°C

(c) 1000°C

(d) 150CPC

(e) 2000°C.

Ans: c

24. In a cycle, the spark lasts roughly for

(a) 1 sec

(b) 0.1 sec

(c) 0.01 sec

(d) 0.001 sec

(e) 0.0001 sec.

Ans: d

25. Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the

following

(a) piston ring and cylinder wear

(b) formation of hard coating on piston skirts

(c) oil sludge in the engine crank case

(d) detonation

(e) forms corrosive acids.

Ans: d

26. Which of the following is false statement. Some of the methods used to reduce diesel

smoke are as follows

(a) using additives in the fuel



(b) engine derating i.e. reducing the maxi-mum flow of fuel

(c) increasing the compression ratio

(d) adherence to proper fuel specification

(e) avoidance of overloading.

Ans: c

27. A high flame speed is obtained in diesel engine when air fuel ratio is

(a) uniform throughout the mixture

(b) chemically correct mixture

(c) about 3-5% rich mixture

(d) about 10% rich mixture

(e) about 10% lean mixture.

Ans: d

28. The knock in diesel engine occurs due to

(a) instantaneous and rapid burning of the first part of the charge

(b) instantaneous atuo iginition of last part of charge

(c) delayed burning of the first part of the charge

(d) reduction of delay period


Ans: a

29. A stoichiometric air-fuel ratio is

(a) chemically correct mixture

(b) lean mixture

(c) rich mixture for idling

(d) rich mixture for over loads

(e) the ratio used at full rated parameters.

Ans: a

Chapter-8 Engine Lubrication and cooling



1. Mechanical efficiency is the ratio of

(a) brake power to heat input

(b) indicated power to heat input

(c) brake power to indicated power

(d) friction loss to heat input

Ans: c

2. Most commonly used lubrication system in automobiles is the

(a) splash system

(b) pressure system

(c) petrol system

(d) gravity system

Ans: b

3. Friction that occurs between the layers of oil film is called

(a) viscous friction

(b) greasy friction

(c) dry friction

(d) boundary friction

Ans: a

4. Crankcase ventilation, is provided

(a) to cool cylinder

(b) to cool crankcase

(c) to cool piston

(d) to remove blow by

Ans: d

5. the most important property of the lubricant is

a) density

(b) viscosity



(c) thermal conductivity


Ans: b

6. The maximum pressure in the lubrication system is controlled by

(a) oil pump

(b) oil filter

(c) valve relief

(d) supply voltage

Ans: c

7. The lubricants commonly used in the automobiles are

(a) animal oils

(b) vegetable oils

(c) mineral oils

(d) cooking oils

Ans: b

8. Detergents are oil additives used to

(a) reduce viscosity

(b) increase fire point

(c)prevent sludge formation

(d) prevent foaming

Ans: c

9. Oil pressure in the dry sump lubrication system is around

(a) 5 bar - 10 bar

(b) 11 bar 15 bar

(c) 3 bar - 8 bar

(d) 1 bar

Ans: c



10. For mep decreases when using

(a) single cylinder engine

(b) smaller number of larger cylinders

(c) larger number of smaller cylinders


Ans: c

11. With increase in compression ratio, mechanical efficiency

(a) increases

(b) decreases

(c) remains constant

(d) compression ratio has nothing to do with ƞmech

Ans: a

12. Blow by losses are

(a) directly proportional to the inlet pressure

(b) inversely proportional to the inlet pressure

(c) proportional to the square root of inlet pressure


Ans: c

13. Mist lubrication system is mainly used in

(a) four-stroke petrol engine

(b) four-stroke diesel engine

(c) two-stroke petrol engine

(d) Wankle engine

Ans: c

14. Additives are added in lubricant to have

(a) detergent-dispersant characteristics

(b) pour point depression



(c) antifoam characteristics


Ans: d

15. The principal surfaces requiring lubrication in an IC engine are

(a) cylinder head

(b) crankcase

(c) inlet and exhaust manifold


Ans: d

16. The heat given to cooling medium in IC engines is about

(a) 50-60%

(b) 30-40%

(c) 10-20%

(d) 60-70%

Ans: b

17. Radiator is provided to

(a) cool the jacket water

(b) pressurise the cooling water

(c) provide additional water flow


Ans: a

18. Thermostat is used in radiators to

(a) control the velocity of water

(b) control distribution of water to various cylinders

(c) control the water temperature

(d) control the pressure of water

Ans: c



19. As the compression ratio increases, there is a

(a) large increase in heat rejection

(b) large decrease in heat reduction

(c) marginal increase in heat rejection

(d) marginal reduction in heat rejection

Ans: d

20. Spark timing other than minimum spark advance for best torque (MBT) results in

(a) less heat rejection

(b) more beat rejection

(c) no effect on heat rejection


Ans: b

21. Direct system of cooling air is one which

(a) cooling water flows by gravity

(b) hot water is continuously cooled and circulated

(c) hot water is simply discharged

(d) water is allowed to evaporate in the cylinder jacket

Ans: c

22. In evaporate cooling systems, heat absorbed per kg of coolant air is equal to

(a) Cp Δ t

(b) Cv Δ t

(c) latent heat of the coolant

(d) (Cp – Cv) Δ t

Ans: c

23. Pump used in the forced cooling system is normally

(a) piston pump

(b) gear pump



(c) vane pump

(d) centrifugal pump

Ans: d

24. Limitations of air cooling systems are

(a) applicable only to large engines

(b) cooling is fast

(c) higher working temperature compared to water cooling


Ans: c

25. Which is more viscous lib oil

(a) SEA 30

(b) SAE 40

(c) SAE 50

(d) SAE 70

(e) SAE 80.

Ans: e

26. In a naturally aspirated diesel engine, the air is supplied by

(a) a supercharger

(b) a centrifugal blower

(c) a vacuum chamber

(d) an injection tube

(e) forced chamber

Ans: c

Chapter-9 Measurement and testing of I C Engine

1. The range of mechanical efficiency for automobile engines is

(a) 0 - 30%

(b) 30 - 50%



(c) 70-80%

(a) 90 - 100%

Ans: c

2. The measurement of frictional power by Willans line is applicable only to

(a) SI engines at a particular speed

(b) CI engines at a particular speed

(c) any engine at a particular speed only


Ans: b

3. Morse test is applicable only to

(a) single cylinder SI engines

(b) single cylinder CI engines

(c) multicylinder CI engines

(d) single and multicylinder SI and CI engines

Ans: c

4. The most accurate method of determining fp is by

(a) Willan's line

(b) Morse test

(c) measurement of brake and indicated power

(d) motoring test

Ans: c

5. In the air box method of measuring air flow, the air box is provided to

(a) have constant temperature

(b) have constant flow

(c) damp out the pulsations

(d) provide constant velocity of flow

Ans: c



6. The air box/swept volume ratio should be in the range for single-cylinder engines

(a) 10- 100%

(b) 200-300%

(c) 500 600%

(d) > 1000%

Ans: c

7. The best method of measuring speed is by

(a) mechanical tachometer

(b) electrical tachometer

(c) magnetic pickup


Ans: c

8. Flame ionization detector is used for measuring

(a) CO

(b) HC

(c) NOx

(d) CO2

Ans: b

9. Chemilumine scence analyzer is used for measuring

(a) NOx

(b) CO

(c) HC

(d) CO2

Ans: a

10. Non-dispersive infra-red analyzer is widely accepted instrument for measuring

(a) NO

(b) HC



(c) CO

(d) CO2

Ans: c

11. Thermal efficiency varies

(a) inversely as sfc

(b) directly as sfc

(c) as square as sfc

(d) as root as sfc

Ans: a

12. Mechanical efficiency is ratio of

(a) fp to bp

(b) fp to ip

(c) bp to ip

(4) ip to fp

Ans: c

13. For N is the rpm, number of power strokes per minute in a four-stroke engine is

(a) 2N

(b) N/2

(c) N

(d) 4N

Ans: b

14. If N is the rpm, number of power strokes per minute in a two-stroke engine is

(a) N

(b) 2N

(c) N/2

(d) 4N

Ans: a



15. The spark timing and combustion rate should be such that

(a) peak pressure occurs at TDC

(b) one half of the total pressure occurs at TDC

(c)ignition delay is reduced


Ans: b

16. Volumetric efficiency is a measure of

(a) speed of the engine

(b) power of the engine

(c) breathing capacity of the engine

(d) pressure rise in the cylinder

Ans: c

17. Indicated power is directly proportional to

(a) torque

(b) air consumption

(c) cylinder peak pressure


Ans: b

18. Turbocharger engines are those in which charge density is increased by

(a) separate air compressors

(b) compressors driven by exhaust gas turbine

(c)cooling inlet air


Ans: b

19. Brake thermal efficiency of SI engine is in the range

(a) 35% to 60%

(b) 25% to 35%



(c) 60% to 80%


Ans: b

20. The volumetric efficiency of a well-designed engine is in the range

(a) 30 to 40%

(b) 40 to 609%

(c) 60 to 70%

(d) 75 to 90%

Ans: d

Chapter-10 Engine Emissions and their control

1. The major contributor of Carbon monoxide is

(a) Motor vehicle

(b) Industrial processes

(c) Stationary fuel combustion

(d) None of the above

Ans: a

2. Apart from hydrocarbons, the main pollutants in the engine exhaust are

(a) CO and CO2

(b) CO2 and NOx

(c) CO and NOx

(d) CO2 and H2O

Ans: c

3. Maximum allowable hydrocarbon in the car emission are approximately

(a) 10 ppm

(b) 100 ppm

(c) 1000 ppm

(d) 5000 ppm



Ans: b

4. CO in the exhaust of a car engine should not be more than:

(a) 0.5%

(b) 2%

(c) 5%

(d) 10%

Ans: a

5. The PCV (Positive Crankcase Ventilation) valve is located between the

(a) Air cleaner and the carburetor

(b) Carburetor and the intake manifold

(c) Intake manifold and air cleaner

(d) Intake manifold and crankcase

Ans: d

6. In case of engines backfiring, the PCV valve:

(a) Opens maximum

(b) Closes

(c) Disintegrates

(d) Sticks in the centre position

Ans: b

7. The position of the PCV valve plunger at idle speed is

(a) Towards the valve outlet side

(b) Towards the valve inlet side

(c) Towards the crankcase

(d) Near the valve centre

Ans: a

8. The function of charcoal granules is to absorb:

(a) Water vapour



(b) Carbon monoxide

(c) Petrol Vapour

(d) Liquid petrol

Ans: c

9. The liquid – vapour separator is located near the

(a) Fuel tank

(b) Carburettor

(c) Charcoal canister

(d) Purge valve

Ans: a

10. EGR (Exhaust Gas Recirculation) system is employed for controlling emissions of:

(a) HC

(b) CO

(c) NOx

(d) HC and CO

Ans: c

11. The main purpose of the diverter valve in the air injection system is to

(a) Close the check valve

(b) Prevent back fire in the exhaust system

(c) Prevent backfire in the inlet manifold

(d) Weaken the air-fuel mixture

Ans: b

12. The catalyst used in the reduction converter is

(a) Copper

(b) Charcoal

(c) Rodium

(d) Platinum



Ans: c

13. The catalyst used in the converter for oxidizing HC and CO is

(a) Copper

(b) Charcoal

(c) Rodium

(d) Platinum

Ans: d

14. In a three-way converter, the first converter controls

(a) HC

(b) CO

(c) NOx

(d) All of these

Ans: c

15. The air fuel ratio required for the efficient operation of a three approximately

(a) 5:1

(b) 10:1

(c) 15:1

(d) 20:1S

Ans: c

16. Which stage of vehicle emission norms presently applicable in India in Internal Combustion

Engine?

(a) Bharat Stage V

(b) Bharat Stage IV

(c) Bharat Stage III

(d) Bharat Stage II

Ans: b



17. Which of the following is one of the major exhaust emissions from CI engines compared to

SI engines?

(a) Oxides of nitrogen

(b) Particulates

(c) CO and CO2

(d) Unburnt hydrocarbon

Ans: b

18. Which of the following causes the photochemical smog?

(a) Excess O2

(b) CO and CO2

(c) Soot and particulate matter

(d) NOx and HC

Ans: d

19. What does the blue smoke in diesel engine indicate?

(a) Unburnt oil

(b) HC

(c) NOx

(d) CO

Ans: a

20. During which condition of the vehicle does NOx emission in SI engine will be lowest?

(a) Cruising

(b) Idling

(c) Accelerating

(d) Decelerating

Ans: b

21. For what purpose is the Rhodium used?

(a) To reduce CO and HC



(b) To reduce NOx

(c) To reduce CO

(d) To reduce HC

Ans: b

22. Why are lead compounds added in petrol?

(a) Reduce knocking

(b) Reduce HC emission

(c) Reduce exhaust temperature

(d) Increase power output

Ans: b

Documents

Chapter 1 Introduction of I. C. Engine