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[MCQ’s]Internal Combustion Engine

Introduction to IC Engine

  1. 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
  2. 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) ignition
    (e) combustion chamber.
    Ans: c
  3. 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 combustion
    (d) air used for forcing burnt gases out of engine’s cylinder during the exhaust period
    (e) air fuel mixture.
    Ans: d
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
    (e) unpredictable.
    Ans: c
  9. The calorific value of gaseous fuels is expressed in terms of
    (a) kcal
    (b) kcal/kg
    (c) kcal/m2
    (d) kcal/n?
    (e) all of the above.
    Ans: d
  10. 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
  11. 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
  12. 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
  13. 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
    (e) all of the above.
    Ans: b
  14. If the compression ratio of an engine working on Otto cycle is increased from 5 to 7, the %age increase in efficiency will be
    (a) 2%
    (b) 4%
    (c) 8%
    (d) 14%
    (e) 27%.
    Ans: d
  15. In case of gas turbines, the gaseous fuel consumption guarantees are based on
    (a) high heat value
    (b) low heat value
    (c) net calorific value
    (d) middle heat value
    (e) calorific value.
    Ans: b
  16. In a typical medium speed 4-stroke cycle diesel engine the inlet valve
    (a) opens at 20° before top dead center and closes at 35° after the bottom dead center
    (b) opens at top dead center and closes at bottom dead center
    (c) opens at 10° after top dead center and closes 20° before the bottom dead center
    (d) may open or close anywhere
    (e) remains open for 200°.
    Ans: a
  17. The pressure and temperature at the end of compression stroke in a petrol engine are of the order of
    (a) 4 – 6 kg/cm2 and 200 – 250°C
    (b) 6 – 12 kg/cm2 and 250 – 350°C
    (c) 12 – 20 kg/cm2 and 350 – 450°C
    (d) 20 – 30 kg/cm2 and 450 – 500°C
    (e) 30 – 40 kg/cm2 and 500 – 700°C.
    Ans: b
  18. The pressure at the end of compression in the case of diesel engine is of the order of
    (a) 6 kg/cm
    (b) 12kg/cmz
    (c) 20 kg/cmz
    (d) 27.5 kg/cmz
    (e) 35 kg/cm
    Ans: e
  19. The maximum temperature in the I.C. engine cylinder is of the order of
    (a) 500- 1000°C
    (b) 1000- 1500°C
    (c) 1500-2000°C
    (d) 2000-2500°C
    (e) 2500-3000°C
    Ans: d
  20. The thermal efficiecny of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will
    (a) increase
    (b) decrease
    (c) be independent
    (d) may increase or decrease depending on other factors
    (e) none of the above.
    Ans: b
  21. Pick up the wrong statement
    (a) 2-stroke engine can run in any direction
    (b) In 4-stroke engine, a power stroke is obtained in 4-strokes
    (c) thermal efficiency of 4-stroke engine is more due to positive scavenging
    (d) petrol engines work on otto cycle
    (e) petrol engines occupy more space than diesel engines for same power output.
    Ans: e
  22. Combustion in compression ignition engines is
    (a) homogeneous
    (b) heterogeneous
    (c) both (a) and (b)
    (d) laminar
    (e) turbulent.
    Ans: b
  23. 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
  24. 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
  25. The temperature of interior surface of cylinder wall in normal operation is not allowed to exceed
    (a) 80°C
    (b) 120°C
    (c) 180°C
    (d) 240°C
    (e) 320°C.
    Ans: c
  26. Crankcase explosion in I.C. engines usuall 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
  27. 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
    (e) all of the above.
    Ans: e
  28. 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
  29. The air requirement of a petrol engine during starting compared to theoretical airequired for complete combustion is
    (a) more
    (b) loss
    (c) same
    (d) may be more or less depending on engine capacity
    (e) unpredictable.
    Ans: b
  30. 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
  31. Which of the following is not an interns combustion engine
    (a) 2-stroke petrol engine
    (b) 4-stroke petrol engine
    (c) diesel engine
    (d) gas turbine
    (e) steam turbine.
    Ans: e
  32. 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
  33. If one cylinder of a diesel engine receives more fuel than the others, then for that cylinder the
    (a) exhaust will be smoky
    (b) piston rings would stick into piston grooves
    (c) exhaust temperature will be high
    (d) engine starts overheating
    (e) scavenging occurs.
    Ans: e
  34. 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
  35. 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
  36. In a typical medium speed 4-stroke cycle diesel engine
    (a) compression starts at 35° after bottom dead center and ends at top dead center
    (b) compression starts at bottom dead center and ends at top dead center
    (c) compression starts at 10° before bottom dead center and, ends just before top dead center
    (d) may start and end anywhere
    (e) none of the above.
    Ans: a
  37. For the same compression ratio
    (a) Otto cycle is more efficient than the Diesel
    (b) Diesel cycle is more efficient’than Otto
    (c) both Otto and Diesel cycles are, equally efficient
    (d) compression ratio has nothing to do with efficiency
    (e) which is more efficient would depend on engine capacity.
    Ans: a
  38. The precess of breaking up or a lipuid into fine droplets by spraying is called
    (a) vaporisation
    (b) carburetion
    (c) ionisation
    (d) injection
    (e) atomisation.
    Ans: e
  39. 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
  40. 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
    (e) Between same temperature limits, both petrol and diesel engines have same efficiency.
    Ans: d
  41. Most high speed compression engines operate on
    (a) Diesel cycle
    (b) Otto cycle
    (c) Dual combustion cycle
    (d) Special type of air cycle
    (e) Carnot cycle.
    Ans: c
  42. The accunmulation 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
  43. Which of the following medium is compressed in a Diesel engine cylinder
    (a) air aione
    (b) air and fuel
    (c) air and lub oil
    (d) fuel alone
    (e) air, fuel and lub oil.
    Ans: a
  44. The air-fuel ratio of the petrol engine is controlled by
    (a) fuel pump
    (b) governor
    (c) injector
    (d) carburettor
    (e) scavenging.
    Ans: d
  45. In a typical medium speed, 4-stroke cycle diesel engine
    (a) fuelinjection 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 deac center
    (d) may start and end anywhere
    (e) none of the above.
    Ans: a
  46. 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
  47. In diesel engine the diesel fuel injected into 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
  48. 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
  49. The rating of a diesel engine, with increase in airintlet temperature, will
    (a) increase linearly
    (b) decrease linearly
    (c) increase parabolically
    (d) decrease parabolically
    (e) first decrease linearly and then increase parabolically.
    Ans: b
  50. 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
  51. 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
    (e) all of the above.
    Ans: c
  52. 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
    (e) all of the above.
    Ans: b
  53. 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
    (e) none of the above.
    Ans: c
  54. 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
  55. The term scavenging is generally associated with
    (a) 2-stroke cycle engines
    (b) 4-stroke cycle engines
    (c) aeroplane engines
    (d) diesel engines
    (e) high efficiency engines.
    Ans: e
  56. In diesel engine, the compression ratio in comparison to expansion ratio is
    (a) same
    (b) less
    (G) more
    (d) variable
    (e) more/less depending on engine capacity.
    Ans: c
  57. The cam shaft of a four stroke I.C. engine running at 1500 rmp will run at
    (a) 1500 rpm
    (b) 750 rpm
    (c) 3000 rpm
    (d) any value independent of engine speed
    (e) none of the above.
    Ans: b
  58. Engine pistons ‘are usually made of aluminium alloy because it
    (a) is lighter
    (b) wears less
    (c) absorbs shocks
    (d) is stronger
    (e) does not react with fuel and lub oil.
    Ans: a
  59. Most high speed compression engines operate on
    (a) Otto cycle
    (b) Diesel cycle
    (c) Dual cycle
    (d) Carnot cycle
    (e) Two stroke cycle.
    Ans: c
  60. The specific fuel consumption of a petrol engine compared to diesel engine of same H.P. is
    (a) same
    (b) more
    (c) less
    (d) less or more depending on operating conditions
    (e) unpredictable.
    Ans: b
  61. A diesel engine as compared to petrol engine (both running ar rated load) is
    (a) more efficient
    (b) less efficient
    (c) equally efficient
    (d) unperdictable
    (e) other factors will decide it.
    Ans: a
  62. The size of inlet valve of.an engine in comparison to exhaust valve is
    (a) more
    (b) less
    (c) same
    (d) more/less depending on capacity of engine
    (e) varies from design to design.
    Ans: b
  63. 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
  64. Which of the following is false statement :
    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
  65. 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
  66. The fuel air ratio in a petrol engine fitted with suction carburettor, operating with dirty air filter as compared to clean filter will be
    (a) higher
    (b) lower
    (c) remain unaffected
    (d) unpredictable
    (e) none of the above.
    Ans: a
  67. 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
  68. The actual volume of fresh charge admitted in 4-stroke petrol engine is
    (a) equal to stroke volume
    (b) equal to stroke volume and clearance volume
    (c) less than stroke volume
    (d) more than stroke volume
    (e) more than cylinder volume.
    Ans: c
  69. The magneto in an automobile is basically
    (c) transformer
    (b) d.c. generator
    (c) capacitor
    (d) magnetic circuit
    (e) a.c. generator.
    Ans: b
  70. 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
    (e) none of the above.
    Ans: c
  71. 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
  72. Supercharging is essential in
    (a) diesel engines
    (b) gas turbines
    (c) petrol engines
    (d) aircraft engines
    (e) marine engines.
    Ans: d
  73. The minimum cranking speed in case of petrol engine is about
    (a) half the operating speed
    (b) one-fourth of operating speed
    (c) 250-300 rpm
    (d) 60-80 rpm
    (e) 10-20 rpm
    Ans: d
  74. In a typical medium speed 4 stroke cycle diesel engine
    (a) exhaust valve opens at 35° before bot-tom dead center and closes at 20° after top dead center
    (b) exhaust valve opens at bottom ‘dead center and closes at top dead center
    (c) exhaust valve opens just after bottom dead center and closes just before top dead center
    (d) may open and close anywhere
    (e) none of the above is true.
    Ans: a
  75. 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
    (e) none of the above.
    Ans: a
  76. The mean effective pressure obtained from engine indicator indicates the
    (a) maximum pressure developed
    (b) minimum pressure
    (c) instantaneous pressure at any instant
    (d) exhaust pressure
    (e) average pressure.
    Ans: e
  77. For the same power developed in I.C. engines, the cheaper system is
    (a) naturally aspirated
    (b) supercharged
    (c) centrifugal pump
    (d) turbo charger
    (e) none of the above.
    Ans: b
  78. 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
  79. Scavenging is usually done to increase
    (a) thermal efficiency
    (b) speed
    (c) power output
    (d) fuel consumption
    (e) all of the above.
    Ans: c
  80. 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
  81. 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
  82. 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
  83. 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
  84. 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
  85. The following volume of air is required for consuming 1 liter of fuel by a four stroke engine
    (a) 1 m3
    (b) 5 m3
    (c) 5-6 m3
    (d) 9-10 m3
    (e) 15-18 m3.
    Ans: d
  86. 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
  87. 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
  88. Diesel engine can work on very lean air fuel ratio of the order of 30 : 1. A petrol engine can also work on such a lean ratio provided
    (a) it is properly designed
    (b) best quality fuel is used
    (c) can not work as it is impossible
    (d) flywheel size is proper
    (e) engine cooling is stopped.
    Ans: c
  89. A diesel engine has
    (a) 1 valve
    (b) 2 valves
    (b) 3 valves
    (d) 4 valves
    (e) no valve.
    Ans: c
  90. A hmh 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
  91. 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
    (e) all ot the above.
    Ans: a
  92. The air-fuel ratio in petrol engines-is controlled by
    (a) controlling valve opening/closing
    (b) governing
    (c) injection
    (d) carburettion
    (e) scavenging and supercharging.
    Ans: d
  93. Volatility of diesel fuel oil is
    (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: d
  94. Which is more viscous lub oil
    (a) SEA 30
    (b) SAE 4£
    (c) SAE 50
    (d) SAE 70
    (e) SAE 80.
    Ans: e
  95. In the opposed piston diesel engine, the combustion chamber is located
    (a) above the piston (/;) below the piston
    (c) between the pistons
    (d) any when
    (e) there is no such criterion.
    Ans: c
  96. 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
  97. 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
  98. In loop scavenging, the top of the piston is
    (a) flat
    (b) contoured
    (c) slanted
    (d) depressed
    (e) convex shaped.
    Ans: b
  99. In the crankcase method of scavenging, the air pressure is produced by
    (a) supercharger
    (b) centrifugal pump
    (c) natural aspirator
    (d) movement of engine piston
    (e) reciprocating pump.
    Ans: c
  100.  Engine pistons are usually made of aluminium alloy because it

A. Is lighter
B. Wear is less
C. Absorbs shocks
D. Is stronger

Answer: Option A
Solution:
Engine pistons are usually made of aluminium alloy because it Is lighter Aluminium alloy are used because they are lighter.

101. The reason for supercharging in any engine is to
A. Increase efficiency
B. Increase power
C. Reduce weight and bulk for a given output
D. Effect fuel economy

Answer: Option C
Solution:

The reason for supercharging in any engine is to Reduce weight and bulk for a given output -A supercharger is an air compressor that increases the pressure or density of air supplied to an internal combustion engine. This gives each intake cycle of the engine more oxygen, letting it burn more fuel and do more work, thus increasing power.

102.Morse test can be conducted for
A. Petrol engines
B. Diesel engines
C. Multi cylinder engines
D. All of these
Answer: Option C
Solution:
Morse test can be conducted for Multi cylinder engines The purpose of Morse test is to obtain the approximate indicated power of a Multi cylinder engine. It consist of
running the engine against the dynamo-meter at a particular speed, cutting out the firing of each cylinder in turn and noting the fall in BP each time while maintaining the
speed constan
103. The cetane (C₁₆H₃₄) which is a straight chain paraffin, is assigned a cetane number of
A. 0
B. 50
C. 100
D. 120
Answer: Option C
Solution:
The cetane (C₁₆H₃₄) which is a straight chain paraffin, is assigned a cetane number of 100
104. Alpha-methyl-naphthalene (C₁₁ H₁₀) has a cetane number of
A. 0
B. 50
C. 100
D. 120
Answer: Option A
Solution:
Alpha-methyl-naphthalene (C₁₁ H₁₀) has a cetane number of 0

105.The working medium of an air standard cycle has constant ___________ throughout the cycle.
(A) pressure
(B) volume
(C) specific heat
(D) mass

ans:C

106.It is assumed that all the processes of an air standard cycle are
(A) reversible
(B) irreversible
(C) adiabatic
(D) isothermal

ans:A

107.The compression ratio of the I.C. engine is
(A) the ratio of volumes of air in cylinder before compression stroke and after compression stroke.
(B) the volume displaced by piston per stroke and clearance volume in the cylinder.
(C) the ratio of pressure after compression and before compression.
(D) swept volume/cylinder volume.

ans:A

108.A petrol engine, during suction stroke, draws
(A) air only
(B) petrol only
(C) a mixture of petrol and air
(D) a mixture of petrol and air and oil

ans:C

109.In a four-stroke cycle engine, the sequence of operations is
(A) suction, compression, expansion, and exhaust
(B) suction, expansion, compression, and exhaust
(C) expansion, compression, suction, and exhaust
(D) compression, expansion, suction, and exhaust

ans:A

 

SI Engine

1-The following is (are) the volatile fuel(s).
Petrol
Alcohol
Benzol
All of the above
(Ans: d)

2-The function of induction system of Spark Ignition (SI) engine is to supply ______ to various cylinders of the engine.
Partly vaporized mixture of fuel and air
Fully vaporized mixture of fuel and air
Liquefied mixture of fuel and air
All of the above
(Ans: a)

3-The following factors affect the process of carburetion
Engine speed
The temperature of incoming air
The volatility of fuel
All of the above
(Ans: d)

4-Which of the following Air-fuel ratio is considered as rich mixture in Spark Ignition (SI) engine?
Below 11:1
Below 15:1
Below 20:1
Above 20:1
(Ans: a)

5-The fuel-air ratios in the range of _____ give maximum economy of fuel
12.5 to 13.5 : 1
14.5 to 15.5 : 1
16.5 to 17.5 : 1
19.5 to 20.5 : 1
(Ans: c)

6-The fuel consumption is least in
Idling range
No load running
Cruising range
High power range
(Ans: c)

7-The pressure in float chamber of carburetor is
1 atm
2 atm
3 atm
4 atm
(Ans: a)

8-The difference of level of tip of main nozzle and fuel level in float chamber of a simple carburetor is called
Nozzle lip
Nozzle dip
Throttle lip
Throttle dip
(Ans: a)

9-In carburetor, Choke is incorporated
Before the venturi
After the venturi
In the venturi
Any of the above
(Ans: a)

10-The following are the compensating devices used
Auxiliary air valve
Auxiliary port
Metering pin
All of the above
(Ans: d)

11-The following method provides the required air-fuel ratios in the economic and power range
Idling system
Accelerating pump
Metering pin method
Pressure reduction method
(Ans: d)

12-The following is (are) the modern carburetors used in automobiles
Solex carburetor
Cartex carburetor
S.U. carburetor
All of the above
(Ans: d)

13-At high altitudes, the automobile requires
Rich mixture
Lean mixture
Correct mixture
Any of the above
(Ans: b)

14-The first vehicle in India equipped with MPFI system in Indian automobile industry
Tata Indica
Daewoo Matiz
Maruti Alto
Chevrolet spark
(Ans: b)

15-‘MPFI’ stands for
Multi point fuel injection
Multi port fuel injection
Manifold point fuel injection
Manifold port fuel injection
(Ans: a)

16-In MPFI _____ is used to spray fuel into engine.
Engine vacuum
Suction pressure of engine
Electric pump
None of the above
(Ans: b)

17-The following is (are) the part(s) of Electronic Control Unit (ECU)
Injector control
Spark advance control
Idling control
All of the above
(Ans: d)

18-The vapour lock problem may be caused in
Pipes
Feed pump
Float chamber
All of the above
(Ans: d)

19. In battery ignition system, the energy required for producing spark is obtained from a _____________ battery.
a) 6 V to 12 V
b) 12 V to 24 V
c) 24 V to 30 V
d) none of the mentioned

Answer: a
Explanation: The battery used in vehicles are between 6 V to 12 V, so in battery ignition system, the energy required for producing spark is obtained from a 6 V to 12 V battery.

20. The essential components of battery ignition system are
a) battery
b) ignition switch
c) ballast resistor
d) all of the mentioned

Answer: d
Explanation: The essential components of battery ignition system are
i) battery
ii) ignition switch
iii) ballast resistor
iv) ignition coil
v) contact breaker
vi) capacitor
vii) distributor
viii) spark plug.

21. The essential components of battery ignition system are
a) ignition coil
b) contact breaker
c) capacitor
d) all of the mentioned

Answer: d
Explanation: The essential components of battery ignition system are
i) battery
ii) ignition switch
iii) ballast resistor
iv) ignition coil
v) contact breaker
vi) capacitor
vii) distributor
viii) spark plug.

22. The essential components of battery ignition system are
a) distributor
b) spark plug
c) none of the mentioned
d) all of the mentioned

Answer: d
Explanation: The essential components of battery ignition system are
i) battery
ii) ignition switch
iii) ballast resistor
iv) ignition coil
v) contact breaker
vi) capacitor
vii) distributor
viii) spark plug.

23. The battery is charged by a __________ driven by the engine.
a) shaft
b) axle
c) dynamo
d) none of the mentioned

Answer: c
Explanation: The battery is charged by a dynamo driven by the engine and shaft and axle are not used in a battery.

24. A lead acid battery consists of a number of cells connected together in series and each having a nominal potential of 2 volts when fully charged.
a) True
b) False

Answer: a
Explanation: None.

25. The lead acid battery is used in ______________ duty commercial vehicles.
a) heavy
b) light
c) large
d) none of the mentioned
View Answer

Answer: b
Explanation: The lead acid battery is used in light duty commercial vehicles while alkaline battery is used in heavy duty commercial vehicles.

26. The alkaline battery is used in ____________ duty commercial vehicles.
a) heavy
b) light
c) large
d) none of the mentioned

Answer: a
Explanation: The alkaline battery is used in heavy duty commercial vehicles while the lead acid battery is used in light duty commercial vehicles.

27. Battery is connected to the primary winding of the ignition coil through an ignition switch and blast resistor.
a) True
b) False

Answer: a
Explanation: None.

28. The ignition system can be turned ON or OFF, with the help of ignition switch.
a) True
b) False

Answer: a
Explanation: None.

29. A blast resistor is provided in parallel with the primary winding to regulate the primary current.
a) True
b) False

Answer: b
Explanation: In fact, a blast resistor is provided in series with the primary winding to regulate the primary current.

30. An eight cylinder engine running at 3000 rpm requires __________ spark per minute.
a) 1000
b) 3000
c) 12000
d) none of the mentioned

Answer: c
Explanation: None.

31. The function of the distributor is to distribute the ignition surges to the individual spark plug in the correct sequence and at the correct instants in time.
a) True
b) False

Answer: a
Explanation: None.

32. When the ignition switch is opened, the primary winding of the coil is connected to the positive terminal post of the storage battery.
a) True
b) False

Answer: b
Explanation: When the ignition switch is closed, the primary winding of the coil is connected to the positive terminal post of the storage battery.

33. The primary voltage increases as the engine speed increases due to the limitations in the current switching capability of the breaker system.
a) True
b) False

Answer: b
Explanation: In fact, the primary voltage decreases as the engine speed increases due to the limitations in the current switching capability of the breaker system.

34. Swirl is the rotational flow of charge within the cylinder about the axis.
a) True
b) False

Answer: a
Explanation: None.

35. The _____________ is defined by the parallel portion of the piston and cylinder head which almost touch each other as the piston approaches T.D.C.
a) turbulence
b) swirl
c) quench area
d) none of the mentioned

Answer: c
Explanation: The quench area is defined by the parallel portion of the piston and cylinder head which almost touch each other as the piston approaches T.D.C. while turbulence consists of randomly dispersed vortices of different sizes which become superimposed into the air and petrol mixture flow stream.

36. ____________ consists of randomly dispersed vortices of different sizes which become superimposed into the air and petrol mixture flow stream.
a) Turbulence
b) Swirl
c) Quench area
d) None of the mentioned

Answer: a
Explanation: Only turbulence consists of randomly dispersed vortices of different sizes which become superimposed into the air and petrol mixture flow stream while quench area is defined by the parallel portion of the piston and cylinder head which almost touch each other as the piston approaches T.D.C.

37. The amount of vortex activity,and the disintegration of others, _____________ the turbulent flow with rising engine speed.
a) increases
b) decreases
c) remains same
d) none of the mentioned

Answer: a
Explanation: None.

38. The degree of turbulence increases _____________ with the piston speed.
a) indirectly
b) directly
c) linearly
d) none of the mentioned

Answer: b
Explanation: The degree of turbulence is directly proportional to piston speed, hence it increases directly with the piston speed.

39. Turbulence decreases the heat flow to the cylinder wall and in the limit excessive turbulence may extinguish the flame.
a) True
b) False

Answer: b
Explanation: In fact, turbulence increase the heat flow to the cylinder wall and in the limit excessive turbulence may extinguish the flame.

40. The flame propagation velocities range from
a) 10 to 15 m/s
b) 15 to 70 m/s
c) 20 to 80 m/s
d) 30 to 90 m/s

Answer: a
Explanation: None.

41. When ignition occurs the nucleus of the flame spreads with the whirling or rotating vortices in the form of ragged burning crust from the initial spark plug ignition site.
a) True
b) False

Answer: a
Explanation: None.

42. Swirl ratio is defined as the ratio of air rotational speed to crankshaft rotational speed.
a) True
b) False

Answer: a
Explanation: None.

43. Abnormal combustion knock produced by surface ignition in SI engines is not harmful as normal combustion knock.
a) True
b) False

Answer: b
Explanation: In fact, abnormal combustion knock produced by surface ignition in SI engines is more harmful than normal combustion knock.

44. In a spark ignition engine combustion which is initiated between the spark plug electrodes spreads across the combustible mixture.
a) True
b) False

Answer: a
Explanation: None.

45. A definite flame front is one which separates the fresh mixture from the products of combustion travels from the spark plug to the other end of the combustion chamber.
a) True
b) False

Answer: a
Explanation: None.

46. The process of autoignition has nothing to do towards engine knock.
a) True
b) False

Answer: b
Explanation: Actually, the process of autoignition leads towards engine knock.

47. In SI engine, ignition lag is reduced if the initial temperature and pressure are
a) decreased
b) increased
c) constant
d) none of the mentioned

Answer: a
Explanation: In SI engine, due to the increment of the initial temperature and pressure are ignition lag is reduced.

48. Auto ignition refers to initiation of combustion without the necessity of a flame.
a) True
b) Fals

Answer: a
Explanation: None.

49. The effects of knocking are
a) noise and roughness
b) mechanical damage
c) carbon deposits
d) all of the mentioned

Answer: a
Explanation: The effects of knocking are
i) noise and roughness
ii) mechanical damage
iii) carbon deposits
iv) increase in heat transfer
v) decrease in power output and efficiency
vi) preignition.

50. The effects of knocking are
a) increase in heat transfer
b) decrease in power output and efficiency
c) preignition
d) all of the mentioned

Answer: a
Explanation: The effects of knocking are
i) noise and roughness
ii) mechanical damage
iii) carbon deposits
iv) increase in heat transfer
v) decrease in power output and efficiency
vi) preignition.

51. Increase of pressure increases the self ignition temperature and the induction period.
a) True
b) False

Answer: b
Explanation: In fact, increase of pressure decreases the self ignition temperature and the induction period.

52. Low engine speeds will give low turbulence and low flame velocities and knock may occur at low speed.
a) True
b) False

Answer: a
Explanation: None.

53. Use of low octane fuel can eliminate detonation.
a) True
b) False

Answer: b
Explanation: No, but the use of high octane fuel can eliminate detonation.

CI Engine

1. NOx is reduced in a CI engine by the use of EGR.
a) increased
b) reduced
c) unpredictable
d) none of the mentioned

Answer: b
Explanation: By using EGR in a CI engine, generally the emission of NOx is reduced.

2. EGR and lower combustion temperatures contribute to an ____________ in solid soot.
a) decreases
b) increases
c) same
d) none of the mentioned

Answer: b
Explanation: Frequent practice of EGR and lower combustion temperatures contribute to an increases in solid soot.

3. Platinum and palladium are two main catalyst materials used for converters on CI engines.
a) True
b) False

Answer: a
Explanation: Platinum and palladium are only the two main catalyst materials that are used for converters on CI engines.

4. Platinum and palladium catalyst promotes the removal of ____________ of the gaseous HC in the exhaust.
a) 30-80%
b) 40-90%
c) 50-100%
d) none of the mentioned

Answer: a
Explanation: In total platinum and palladium catalyst promote the removal of 30-80% of the gaseous HC in the exhaust.

5. Platinum and palladium catalyst promotes the removal of _____________ of the gaseous CO in the exhaust.
a) 30-80%
b) 40-90%
c) 50-100%
d) none of the mentione

Answer: b
Explanation: In total platinum and palladium catalyst promote the removal of 40-90% of the gaseous HC in the exhaust.

6. Diesel fuel contains sulphur impurities, and this leads to poisoning of the catalyst materials.
a) True
b) False

Answer: a
Explanation: None.

7. Traps are filter-like system often made of ceramic in the form of a monolith or mat, or metal wire mesh.
a) True
b) False

Answer: a
Explanation: None.

8. Traps typically remove _____________ of particulates in the exhaust flow.
a) 30-80%
b) 40-90%
c) 50-100%
d) 60-90%

Answer: d
Explanation: 60-90% of particulates in the exhaust flow are removed by traps.

9. Regeneration does not consists of combusting the particulates in the excess oxygen contained in the exhaust of the lean operating CI engine.
a) True
b) False

Answer: b
Explanation: In fact, regeneration consists of combusting the particulates in the excess oxygen contained in the exhaust of the lean operating CI engine.

10. With greatly increased mixing efficiency and speeds, large regions of fuel-rich mixtures can be avoided when combustion starts.
a) True
b) False
Answer: a
Explanation: None.

11. In which of the following fuel injector is used?
a) Compression-ignition engines
b) Spark-ignition engines
c) Steam engines
d) Sterling engines

Answer: a
Explanation: In compression – ignition (CI) engines, only air is compressed in the cylinder and by means of fuel – injection system fuel is injected into the cylinder. In CI engines, compressed air temperature plays a main role in combustion.

12. At which stroke the fuel is injected in the CI engine?
a) Suction stroke
b) Compression stroke
c) Expansion stroke
d) Exhaust stroke

Answer: b
Explanation: Fuel injection in the CI engines start at the end of the compression stroke. Fuel is injected directly into the combustion chamber.

13. Which of the following is the port fuel – injection system?
a) D – MPFI
b) L – MPFI
c) GDI
d) TBI

Answer: b
Explanation: L – MPFI system uses port fuel – injection. In this, the fuel metering is regulated by the speed of the engine and the amount of air that actually enters the engine. D – MPFI system uses manifold injection. GDI system uses direct injection. TBI system uses throttle body injection.

14. What is the range of pressure is achieved in the injection pump?
a) 120 – 200 bar
b) 10 – 20 bar
c) 400 – 500 bar
d) < 10bar

Answer: a
Explanation: The purpose of the fuel injection pump is to increase the pressure of the quantity of fuel in the range of 120 – 200 bars and deliver it at the correct instant to the injector.

15. In pneumatic governor, which of the following control the amount of vacuum applied to the diaphragm?
a) Spring
b) Accelerator pedal
c) Butterfly valve
d) Lever

Answer: a
Explanation: The vacuum applied to the diaphragm is controlled by the accelerator pedal. The diaphragm is in contact with the fuel pump control rack.

16. A six-cylinder, four-stroke diesel engine develops a power of 200 kW at 2000 revolution per minute. The brake specific fuel consumption is 0.3 kg / kW – h. What is the time for injection if the injection takes place over 20° crank angle?
a) 1 millisecond
b) 2 milliseconds
c) 1.5 milliseconds
d) 1.66 milliseconds

Answer: d
Explanation: Power output / cylinder = 200 / 6 = 33.33 kW. Fuel consumption / cylinder = 33.33 * brake specific fuel consumption = 33.33 * 0.3 = 9.99 kg / h. Time for injection = (20 * 60) / (360 * 2000) = 1.667 * 10-3 sec = 1.66 milliseconds.

17. What is the spray cone angle in the Pintle nozzle?
a) 60°
b) 15°
c) 25°
d) 45°

Answer: a
Explanation: Spray cone angle of a Pintle nozzle is 60°. The main advantage of this nozzle is that it avoids weak injection and dribbling. Also, it prevents the carbon deposition on the nozzle hole.

18. Which of the following is not the part of the injector assembly?
a) Needle valve
b) Nozzle
c) Diaphragm
d) Compressor spring

Answer: c
Explanation: The injector assembly consists of a needle valve, nozzle, compressor spring, and an injector body. The diaphragm is a part of the injection pump governor. A nozzle is used to atomize the fuel and break up into small particles.

19. Which of the following is not the function of the fuel injection system?
a) Time the fuel injection
b) Filter the fuel
c) Atomize the fuel to fine particles
d) Control the engine speed

Answer: d
Explanation: The functions of the fuel injection system are to filter the fuel, to time the fuel injection, to break up the fuel into small particles.

20. The cold start injector provides a lean air-fuel ratio.
a) True
b) False

Answer: b
Explanation: The cold start injector gives a rich air-fuel ratio. Its objective is to supply the engine with additional fuel to make the rich mixture in cold temperatures where the air density is increased and additional fuel is required.

21. The methods used on fuel injection are :
a) air injection
b) mechanical injection
c) solid fuel injection
d) all of the mentioned

Answer: d
Explanation: The methods used on fuel injection are air injection, mechanical injection and solid fuel injection.

22. Removal of air from the pipeline is termed as ____________ in injection system.
a) bleeding
b) wound
c) sweating
d) none of the mentioned

Answer: a
Explanation: Generally, the removal of air from the pipeline is termed as bleeding in injection system.

23. The usual types of diesel injectors are :
a) single hole injector
b) multi hole injector
c) long stem injector
d) all of the mentioned

Answer: d
Explanation: The types of diesel injectors are single hole injector, multi hole injector and long stem injector.

24. In pre-chamber and swirl type of combustion system ______________ is used.
a) single hole injector
b) multi hole injector
c) long stem injector
d) pintle nozzle

Answer: d
Explanation: In pre-chamber and swirl type of combustion system pintle nozzle is used and not the other nozzles.

25. _______________ is used to enable cold starting, with out the use of a heater plug.
a) Pintaux nozzle
b) Multi hole injector
c) Long stem injector
d) Pintle nozzle

Answer: a
Explanation: Generally, intaux nozzle is used to enable cold starting, with out the use of a heater plug.

26. If one or more nozzles are not spraying correctly then ________________ occurs.
a) dripping
b) misfiring
c) cold firing
d) none of the mentioned

Answer: b
Explanation: If one or more nozzles are not spraying correctly then misfiring occurs and not cold firing.

27. Solid injection is also called ________________
a) air injection
b) mechanical injection
c) compression fuel injection
d) none of the mentioned
View Answer

Answer: b
Explanation: Generally, solid injection is also called mechanical injection.

28. Fuel is injected into the cylinder at the end of ______________ stroke.
a) suction
b) compression
c) expansion
d) exhaust
Answer: b
Explanation: Fuel is injected into the cylinder at the end of compression stroke and not at suction or expansion stroke.

29. The beginning and end of the injection should be sharp.
a) True
b) False
Answer: a
Explanation: None.

30. In _____________ injection system only one pump is sufficient for multi-cylinder engine.
a) air
b) mechanical
c) compression fuel
d) common rail
Answer: d
Explanation: None.

31. In a fuel-injection system, the amount of fuel delivered into the air stream going to the engine is controlled by a pump which forces the fuel under pressure.
a) True
b) False
Answer: a
Explanation: None.

32. The requirements met by the injection system are:
a) Proper atomization of fuel into very fine droplets
b) Proper spray pattern to ensure rapid mixing of fuel and air
c) Uniform distribution of fuel droplets throughout the combustion chamber
d) All of the mentioned
Answer: d
Explanation: None.

33. In an air injection system, __________ is forced into the cylinder by means of compressed air.
a) air
b) fuel
c) water
d) none of the mentioned
Answer: b
Explanation: In an air injection system, generally fuel is forced into the cylinder by means of compressed air.

34. Fuel injector is used for
a) Gas engines
b) CI engines
c) SI engines
d) None of the mentioned
Answer: b
Explanation: Fuel injector is used for CI engines and not for SI engine and gas engines.

35. Advantage of air injection system is
a) cheaper fuels can be used
b) mep is high
c) fine atomization and distribution of the fuel
d) all of the mentioned
Answer: d
Explanation: None.

36. Commonly used injection system in automobiles is
a) air injection
b) solid injection
c) combination of (a) and (b)
d) none of the mentioned
Answer: b
Explanation: None.

37. Fuel injection pressure in solid injection system is around
a) < 10 bar
b) 10-20 bar
c) 30-50 bar
d) 200-250 bar
Answer: d
Explanation: None.

38. Fuel filters do not use generally
a) oil
b) paper
c) cloth
d) felt
Answer: b
Explanation: Generally paper is not used as fuel filters.

39. 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
Answer: c
Explanation: None.

40. Advantage of fuel injection in SI engine is
a) low initial cost
b) low maintenance requirements
c) increased volumetric efficiency
d) none of the mentioned
Answer: c
Explanation: None.

41. A six cylinder, four-stroke diesel engine develops 125 kW at 3000 rpm. Its brake specific fuel consumption is 200gm/kW h. Calculate the quantity of fuel to be injected per cycle per cylinder. Specific gravity of the fuel may be taken as 0.85.
a) 0.0545 cc/cycle
b) 0.545 cc/ cycle
c) 5.45 cc/cycle
d) none of the mentioned
Answer: a

Explanation: Fuel consumed/hour = bsfc x Power output

= 200 x 10-2 x 125 = 25 kg
Fuel consumption/cylinder = 25/6 = 4.17 kg/h
Fuel consumption/cycle = (Fuel consumption/minute)/nwhere n = N/2 for four-stroke cycle engines = (4.17/60)/(3000/2)
= 4.63 x 10-5 kg
= 0.0463 gm
Volume of fuel injected = 0.0463/0.85
= 0.0545 cc/cycle.

42. In CI engine, combustion occurs by the high temperature produced by the compression of the air.
a) True
b) False
Answer: a
Explanation: None.

43. In the CI engine, the intake is air alone and the fuel is injected at high pressure in the form of fine droplets at the start of compression.
a) True
b) False
Answer: b
Explanation: No, but actually, in the CI engine, the intake is air alone and the fuel is injected at high pressure in the form of fine droplets near the end of compression.

44. The phases of CI engine combustion are
a) ignition delay period
b) period of rapid combustion
c) period of controlled combustion
d) all of the mentioned
Answer: d
Explanation: The three phases of CI engine combustion are
a) ignition delay period
b) period of rapid combustion
c) period of controlled combustion.

45. The rate of pressure rise depends on the amount of fuel present at the end of delay period, degree of turbulence, fineness of atomization and spray pattern.
a) True
b) False
Answer: a
Explanation: None.

46. The factors affecting combustion in CI engine are
a) ignition quantity of fuel
b) injection pressure of droplet size
c) injection advance angle
d) all of the mentioned
Answer: a
Explanation: The factors affecting combustion in CI engine are
1) ignition quantity of fuel
2) injection pressure of droplet size
3) injection advance angle
4) compression ratio
5) intake temperature
6) jacket water temperature
7) intake pressure
8) engine speed
9) load and air to fuel ratio
10) engine size
11) type of combustion chamber.

47. The factors affecting combustion in CI engine are
a) compression ratio
b) intake temperature
c) jacket water temperature
d) all of the mentioned
Answer: a
Explanation: The factors affecting combustion in CI engine are
1) ignition quantity of fuel
2) injection pressure of droplet size
3) injection advance angle
4) compression ratio
5) intake temperature
6) jacket water temperature
7) intake pressure
8) engine speed
9) load and air to fuel ratio
10) engine size
11) type of combustion chamber.

48. The factors affecting combustion in CI engine are
a) intake pressure
b) engine speed
c) load and air to fuel ratio
d) all of the mentioned
Answer: a
Explanation: The factors affecting combustion in CI engine are
1) ignition quantity of fuel
2) injection pressure of droplet size
3) injection advance angle
4) compression ratio
5) intake temperature
6) jacket water temperature
7) intake pressure
8) engine speed
9) load and air to fuel ratio
10) engine size
11) type of combustion chamber.

49. Towards the end of the compression stroke when injection of the fuel into the combustion chamber commences, the quantity of fuel discharged is spread out over a predetermined period.
a) True
b) False
Answer: a
Explanation: None.

50. The rate of burning does not depends on the relative movement of the burning droplets to the surrounding air charge.
a) True
b) False
Answer: b
Explanation: In fact, the rate of burning depends on the relative movement of the burning droplets to the surrounding air charge.

51. In CI engines fuel is injected into the combustion chamber at about 15ºC ___________ TDC during compression stroke.
a) after
b) before
c) at
d) none of the mentioned
Answer: b
Explanation: None.

Engine Lubrication/Engine Cooling/Turbocharging-supercharging

1-Lubricating oil
(A) Minimizes wear in moving parts
(B) Helps in keeping the parts cool
(C) Washes away and carries away dirt
(D) All of the above
(Ans: D)

2-Viscosity index (VI) is a measure for the change of viscosity with change in
(A) Temperature
(B) Pressure
(C) Volume
(D) All of the above
(Ans: A)

3-The following type of Lubrication system is used in two stroke engines
(A) Petroil (mist) system
(B) Wet sump system
(C) Dry sump system
(D) All of the above
(Ans: D)

4-In the following system, lubricating oil is carried in separate tanks from where it is fed to the engine
(A) Mist lubrication system
(B) Wet sump system
(C) Dry sump system
(D) Splash system
(Ans: C)

5-The following type of Lubrication system is used in Aircraft Engines
(A) Mist lubrication system
(B) Wet sump system
(C) Dry sump system
(D) Splash system
(Ans: C)

6-The following type(s) of Oil pump(s) is (are) used in Engine Lubrication system
(A) Gear type
(B) Rotor type
(C) Plunger type
(D) All of the above
(Ans: D)

7-The following is (are) oil pressure gauge(s)
(A) Pressure expansion type
(B) Electric type
(C) both (A) and (B)
(D) None of the above
(Ans: C)

8-The purpose of crankcase ventilation is to
(A) remove harmful particles from the engine
(B) provide proper lubrication to the engine
(C) provide air for combustion to the engine
(D) all of the above
(Ans: A)

9-The following part(s) is(are) lubricated by splash system
(A) Piston and piston rings
(B) Tappets
(C) Cams on camshaft
(D) All of the above
(Ans: D)

10-The following part is not lubricated by Pressure feed system
(A) Timing gears
(B) Valve rods and Push rods
(C) Rocker arms
(D) Main bearings of crankshaft
(Ans: B)

11.Which of the following parts are lubricated by splash system?
(A) Piston and piston rings
(B) Tappets
(C) Cams on camshaft
(D) All of the above

ans:D

12.Which of the following part is not lubricated by a pressure feed system?
(A) Timing gears
(B) Valve rods and Pushrods
(C) Rocker arms
(D) Main bearings of the crankshaft

ans:B

13.Mist lubrication system is used for ____________ stroke cycle engines.
(A) four
(B) two
(C) radial
(D) all of the above

ans:B

14.Splash system is suitable for
(A) low and medium speed engines
(B) high and medium speed engines
(C) only high-speed engines
(D) all of the above

ans:B

15.Wet sump lubrication system employs a large capacity oil sump at the base of the crank chamber, from which the oil is drawn by a ____ and delivered to various parts.
(A) low pressure oil pump
(B) high pressure oil pump
(C) oil pump
(D) vacuum pump

ans:A

16. Lubricating grease is a solid to semi-solid dispersion of a thickening agent in liquid lubricant.
a) True
b) False

Answer: a
Explanation: None.

17. Greases perform better than oils under conditions requiring
a) high bearing loads and shock loads
b) slow journal speed
c) temperature extremes
d) all of the mentioned
Answer: d
Explanation: Greases perform better than oils under conditions requiring
a) high bearing loads and shock loads
b) slow journal speed
c) temperature extremes
d) cleanliness or avoidance of splash
e) minimum attention
f) a seal against external contaminants
g) large bearing clearances.

18. Greases perform better than oils under conditions requiring
a) cleanliness or avoidance of splash
b) minimum attention
c) a seal against external contaminants
d) all of the mentioned
Answer: d
Explanation: Greases perform better than oils under conditions requiring
a) high bearing loads and shock loads
b) slow journal speed
c) temperature extremes
d) cleanliness or avoidance of splash
e) minimum attention
f) a seal against external contaminants
g) large bearing clearances.

19. The various types of greases used for lubrication are
a) calcium soap greases
b) sodium soap greases
c) aluminium soap greases
d) all of the mentioned
Answer: d
Explanation: The various types of greases used for lubrication are
a) calcium soap greases
b) sodium soap greases
c) aluminium soap greases
d) mixed soap greases
e) barium soap greases
f) lithium soap greases
g) pure petroleum greases.

20. Wet sump lubrication system employ a large capacity oil sump at the base of crank chamber, from which the oil is drawn by a low pressure oil pump and delivered to various parts.
a) True
b) False
Answer: a
Explanation: None.

21. Splash system is suitable for high and medium speed engines having moderate bearing load pressures.
a) True
b) False
Answer: b
Explanation: In fact, splash system is suitable for low and medium speed engines having moderate bearing load pressures.

22. Semi pressure system is a combination of splash and pressure systems.
a) True
b) False
Answer: a
Explanation: None.

23. Semi pressure system does not enables higher bearing loads and engine speeds to be employed as compared to splash system.
a) True
b) False
Answer: b
Explanation: Semi pressure system enables higher bearing loads and engine speeds to be employed as compared to splash system.

24. In full pressure system, oil from oil sump is pumped under pressure to the various parts requiring lubrication.
a) True
b) False
Answer: a
Explanation: None.

25. Full pressure sump lubrication system is generally adopted for high capacity engines.
a) True
b) False
Answer: b
Explanation: Dry sump lubrication system is generally adopted for high capacity engines.

26. The gasoline engine requires much ____________ air than a diesel engine.
a) less
b) more
c) equal
d) none of the mentioned
Answer: b
Explanation: As a gasoline engine works on a mixture of air and gasoline, therefore the gasoline engine requires much more air than a diesel engine.

27. The turbocharged diesel engine requires ____________ cooling air than naturally aspired diesel engines.
a) less
b) more
c) equal
d) none of the mentioned
Answer: a
Explanation: As the turbocharged engine produces less heat so, the turbocharged diesel engine requires less cooling air than naturally aspired diesel engines.

28. The heat flow to water jackets, on an average, is about ____________ for large engines.
a) 500 kJ/kW-h
b) 4200 kJ/kW-h
c) 5700 kJ/kW-h
d) none of the mentioned
Answer: b
Explanation: The heat flow to water jackets, on an average is about 4200 kJ/kW-h for large engines and it is about 500-5700 kJ/kW-h for small engines.

29. The heat flow to water jackets, on average, is about ____________ for small engines.
a) 500-6200 kJ/kW-h
b) 400-4200 kJ/kW-h
c) 500-5700 kJ/kW-h
d) none of the mentioned
Answer: c
Explanation: The heat flow to water jackets, on average, is about 500-5700 kJ/kW-h for small engines and is about 4200 kJ/kW-h for large engines.

30. What is the outlet cooling water temperature for large engines?
a) about 50ºC
b) 60 to 65ºC
c) 80ºC
d) none of the mentioned
Answer: a
Explanation: The outlet cooling water temperature for large engines is about 50ºC and the outlet cooling water temperature for medium engines is 60 to 65ºC.

31. What is the outlet cooling water temperature for medium engines?
a) about 50ºC
b) 60 to 65ºC
c) 80ºC
d) none of the mentioned
Answer: b
Explanation: The outlet cooling water temperature for medium engines is 60 to 65ºC and the outlet cooling water temperature for small engines is 80ºC.

32. What is the outlet cooling water temperature for small engines?
a) about 50ºC
b) 60 to 65ºC
c) 80ºC
d) none of the mentioned
Answer: c
Explanation: The outlet cooling water temperature for small engines is 80ºC while the outlet cooling water temperature for medium engines is 60 to 65ºC and the outlet cooling water temperature for small engines is 80ºC.

33. In thermo-syphon system, the radiator should be kept well above the engine, to provide a height for natural circulation.
a) True
b) False
Answer: a
Explanation: None.

34. Turbochargers are centrifugal compressors driven by the exhaust gas turbines.
a) True
b) False
Answer: a
Explanation: None.

35. A typical petrol engine may harness up to ____________ of the energy contained in the fuel supplied.
a) 20%
b) 30%
c) 40%
d) none of the mentioned
Answer: b
Explanation: Up to 30% of the energy contained in the fuel supplied is harnessed in a typical petrol engine.

36. ____________ of fuel energy is wasted as heat energy to friction, pumping and dynamic movement.
a) 7%
b) 9%
c) 16%
d) 38%
Answer: a
Explanation: Approximately 7% of fuel energy is wasted as heat energy to friction, pumping and dynamic movement and 9% of fuel energy is wasted as heat energy to surrounding air.

37. ____________ of fuel energy is wasted as heat energy to surrounding air.
a) 7%
b) 9%
c) 16%
d) 38%
Answer: b
Explanation: 9% of fuel energy is wasted as heat energy to surrounding air while 16% of fuel energy is wasted as heat energy to engine’s coolant system.

38. ____________ of fuel energy is wasted as heat energy to engine’s coolant system.
a) 7%
b) 9%
c) 16%
d) 38%
Answer: c
Explanation: 16% of fuel energy is wasted as heat energy to engine’s coolant system while approximately 7% of fuel energy is wasted as heat energy to friction, pumping and dynamic movement and 9% of fuel energy is wasted as heat energy to surrounding air.

39. ____________ of fuel energy is wasted as heat energy to outgoing exhaust gases.
a) 7%
b) 9%
c) 16%
d) 38%
Answer: d
Explanation: 38% of fuel energy is wasted as heat energy to outgoing exhaust gases and 16% of fuel energy is wasted as heat energy to engine’s coolant system while approximately 7% of fuel energy is wasted as heat energy to friction, pumping and dynamic movement and 9% of fuel energy is wasted as heat energy to surrounding air.

40. The turbocharger relies solely on extracting up to a third of the wasted energy passing out from the engine’s cylinders to impart power to the turbine wheel and compressor wheel assembly.
a) True
b) False
Answer: a
Explanation: The turbocharger relies solely on extracting up to a third of the wasted energy passing out from the engine’s cylinders to impart power to the turbine wheel and compressor wheel assembly.

41. Turbocharged engines produce lower cylinder volumetric efficiencies compared with the normally aspirated induction systems.
a) True
b) False
Answer: b
Explanation: In fact turbocharged engines produce higher cylinder volumetric efficiencies compared with the normally aspirated induction systems.

42. The compression of the charge entering the cells of the impeller depends upon the centrifugal force effect which decreases with the square of the rotational speed of the impeller wheel.
a) True
b) False
Answer: b
Explanation: In fact the compression of the charge entering the cells of the impeller depends upon the centrifugal force effect which increases with the square of the rotational speed of the impeller wheel.

43. When the engine is suddenly accelerated there will be a small time delay before the extra energy discharged into the turbine housing volute can speed up the turbine wheel.
a) True
b) False
Answer: a
Explanation: Yes, when the engine is suddenly accelerated there will be a small time delay before the extra energy discharged into the turbine housing volute can speed up the turbine wheel.

44. Supercharging of S.I engines is employed only for aircraft and racing car engines.
a) True
b) False
Answer: a
Explanation: Supercharging requires when speed is taken in consideration so, supercharging of S.I engines is employed only for aircraft and racing car engines.

45. ____________ in supercharging pressure increases the tendency to detonate and pre-ignite.
a) Decrease
b) Increase
c) Unpredictable
d) None of the mentioned
Answer: a
Explanation: Detonation and pre-ignition are increased by increase in supercharging pressure.

46. The supercharged petrol engines have a lower fuel consumption than naturally aspirated engines.
a) True
b) False
Answer: b
Explanation: Actually, the supercharged petrol engines have a greater fuel consumption than naturally aspirated engines.

47. Increased intake pressure and temperature reduces ignition delay and decreases flame speed.
a) True
b) False
Answer: b
Explanation: In fact, increased intake pressure and temperature reduces ignition delay and increases flame speed.

48. The increased flame speeds make the petrol engine more sensitive to fuel-air ratio and engine cannot run on strong mixtures without knock.
a) True
b) False
Answer: b
Explanation: Actually, the increased flame speeds make the petrol engine more sensitive to fuel-air ratio and engine cannot run on weak mixtures without knock.

49. Rich mixtures are used to control detonation, which further increases the specific fuel consumption of the engine.
a) True
b) False
Answer: a
Explanation: None.

50. The ignition timings and thermal load on the engine affect the knock limit of CI engine.
a) True
b) False
Answer: b
Explanation: No, in fact the ignition timings and thermal load on the engine affect the knock limit of SI engine.

51. The ignition must be retarded at high intake pressure and temperature.
a) True
b) False
Answer: a
Explanation: None.

52. The power developed by the turbocharger is not sufficient to drive the compressor, and overcome its mechanical friction.
a) True
b) False

Answer: b
Explanation: In fact, the power developed by the turbocharger is sufficient to drive the compressor, and overcome its mechanical friction.

53. The loss in piston work due to early opening of the exhaust valve is less than offset by better charging and scavenging of the engine.
a) True
b) False
Answer: b
Explanation: No, in fact, the loss in piston work due to early opening of the exhaust valve is more than offset by better charging and scavenging of the engine.

Engine Testing and performance

1. For which of the following engines a prony brake is used to measure brake power?
a) single cylinder engine
b) low speed engine
c) low power engine
d) variable speed engine
Answer: d
Explanation: Prony brake is used to measure the brake power of variable speed engines.

2. What does scavenging air mean?
a) Burnt air containing combustion products
b) Air sent under compression
c) Forced air for cooling the engine cylinder
d) Air used for forcing the burnt gases out of cylinder during the exhaust period
Answer: d
Explanation: Scavenging air is defined as the air used for forcing the burnt gases out of cylinder during the exhaust period.

3. ____________ is the basic requirement of a good combustion chamber.
a) Low volumetric efficiency
b) High compression ratio
c) Low compression ratio
d) High power output and high thermal efficiency
Answer: d
Explanation: The basic requirement of a good combustion chamber are:
i) High power output
ii) High thermal efficiency and low specific fuel consumption
iii) smooth engine operation
iv) reduced exhaust pollutants.

4. ____________ is the method of governing used in petrol engine.
a) Quality governing
b) Hit and mass governing
c) Quantity governing
d) All of the mentioned
Answer: a
Explanation: Quality governing is generally used in petrol engines as the quantity of air -fuel mixture flowing into the cylinder is varied accordingly and this may be done by decreasing the lift of the inlet valve or by throttling the mixture before it is made to enter the engine cylinder.

5. Hunting occurs due to which of the following?
a) Faulty governor
b) Poor control by the governor
c) Over control by the governor
d) Bad engine design
Answer: b
Explanation: Hunting occurs due to load variation and this is only when the governor is not controlled properly.

6. Maximum torque is generated by an engine when ______________
a) it runs at lowest speed
b) it develops maximum power
c) it consumes maximum fuel
d) it runs at maximum speed
Answer: a
Explanation: Maximum torque is generated by an engine when it runs at lowest speed while maximum power is developed when the engine rums at its maximum speed.

7. With an increase of the number of cylinders in a multicylinder engine the power to weight ratio ______________
a) decreases
b) increases
c) remains unaffected
d) none of the mentioned
Answer: c
Explanation: The power to weight ratio remains unaffected even after if the number of cylinders in a multicylinder is increased because as the number of cylinders increases, torque is smoother and less flywheel mass is needed.

8. Radiator tubes are generally made of______________
a) cast iron
b) steel
c) plastics
d) brass
Answer: d
Explanation: Brass is used to make radiator pipes due to its heat resistance capacities.

9. Automobile gears are generally made of ______________
a) cast iron
b) stainless steel
c) alloy steel
d) mild steel
Answer: c
Explanation: Steel mixed with copper, zinc and tin is used to make gears in automobiles.

10. ____________ is used to check the state of charge of a battery.
a) Battery charger
b) Hygrometer
c) Hydrometer
d) Battery eliminator
Answer: a
Explanation: Battery charger is used to check the state of charge of a battery while hygrometer is used to check the air humidity and hydrometer is used to check the specific gravity.

11.The mean effective pressure obtained from the engine indicator indicates the
(A) maximum pressure developed
(B) minimum pressure
(C) instantaneous pressure at any instant
(D) average pressure

ans:D

12.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

ans:C

13.The basic measurement and testing parameters are
(A) friction power
(B) indicated power
(C) brake power
(D) all of the above

ans:D

14._____________ is the difference between indicated and brake power of an engine.
(A) Friction power
(B) Overall power
(C) Net power
(D) None of the mentioned

ans:A

15._____________ is also known as fuel rate extrapolation method.
(A) Morse test
(B) Motoring test
(C) Willan’s line method
(D) Retardation test

ans:C

16. 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
Answer: b
Explanation: Unburnt hydrocarbons are one of the major exhaust emissions from CI engines. The components in diesel fuel have higher molecular weight.

17. Which of the following causes the photochemical smog?
a) Excess O2
b) CO and CO2
c) Soot and particulate matter
d) NOx and HC
Answer: d
Explanation: NOx is one of the primary causes of photochemical smog. This smog is formed by the photochemical reaction of automobile exhaust and atmospheric air in the presence of sunlight.

18. What does the blue smoke in diesel engine indicate?
a) Unburnt oil
b) HC
c) NOx
d) CO
Answer: a
Explanation: Blue smoke comes out from the exhaust when there is unburnt oil in the diesel engine. A very thin layer of the oil gets deposited on the cylinder wall to provide the lubrication between the walls and the moving piston.

19. During which condition of the vehicle does NOx emission in SI engine will be lowest?
a) Cruising
b) Idling
c) Accelerating
d) Decelerating
Answer: b
Explanation: NOx emissions are lowest in SI engine during idling. NOx is created from nitrogen in the air. Nitrogen can also be found in fuel blends.

20. 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
Answer: b
Explanation: Rhodium is used to reduce NOx. It is used to clean vehicle emission. It is mixed with the other two metals – platinum and palladium.

21. Why is the fumigation technique used?
a) To control HC
b) To control NOx
c) To control CO
d) To control smoke
Answer: d
Explanation: The fumigation technique is used to control smoke. Fumigation is injecting gaseous or liquid fuel into the intake of air steam of CI engines. There are two types of smoke: hot smoke and cold smoke.

22. Why are lead compounds added in petrol?
a) Reduce knocking
b) Reduce HC emission
c) Reduce exhaust temperature
d) Increase power output
Answer: b
Explanation: The lead compounds are added in petrol to reduce the HC emission. The additive TEL (Tetraethyl Lead) was added to increase the octane number. The resulting lead in the engine exhaust was a poisonous pollutant.

23. Which of the following cannot be reduced by thermal converters?
a) CO
b) HC
c) Soot
d) NOx
Answer: d
Explanation: NOx emission cannot be reduced using a thermal converter. Thermal converters are high-temperature chambers through which the exhaust gas flows.

24. What can be reduced by using exhaust gas recirculation (EGR) effectively?
a) CO
b) NOx
c) HC
d) CO and HC
Answer: b
Explanation: The most effective way of reducing NOx emission is to hold combustion chamber temperatures down. Using this also reduces the thermal efficiency of the engine.

25. Three-way catalytic converters reduce the emission of CO, HC, and soot.
a) True
b) False
Answer: b
Explanation: Three-way catalytic converters reduce the emission of CO, NOx, and HC. They are chambers contain catalytic material. It promotes the oxidation of the emission contained in the exhaust flow.

26.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) Carbon monoxide and Carbon dioxide
(D) Unburnt hydrocarbon

ans:B

27.Why lead compounds added in petrol?
(A) Increase power output
(B) Reduce knocking
(C) Reduce exhaust temperature
(D) Reduce HC emission

ans:D

28.What can be reduced by using exhaust gas recirculation (EGR) effectively?
(A)
(B)
(C)
(D)

ans:B

29.What is the major difference between BS-IV and BS-VI norms?
(A) BS-IV fuels contain 80 ppm sulphur and BS-VI fuels contain 60 ppm sulphur
(B) BS-IV fuels contain 100 ppm sulphur and BS-VI fuels contain 90 ppm sulphur
(C) BS-IV fuels contain 50 ppm sulphur and BS-VI fuels contain 10 ppm sulphur
(D) BS-IV fuels contain 150 ppm sulphur and BS-VI fuels contain 110 ppm sulphur

ans:C

 

Alternative Fuels

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
d) all of the mentioned
Answer: b
Explanation: None.

2. Paraffins are generally represented by
a) CnHn
b) CnH2n
c) CnH2n+2
d) CnH2n-6
Answer: c
Explanation: Paraffins are generally represented by CnH2n+2 while olefins are generally represented by CnHn .

3. Paraffins have molecular structure of
a) chain saturated
b) chain unsaturated
c) ring saturated
d) ring unsaturated
Answer: a
Explanation: None.

4. Olefins are generally represented by
a) CnHn
b) CnH2n
c) CnH2n+2
d) CnH2n-6
Answer: a
Explanation: Olefins are represented by CnHn and paraffins are generally represented by CnH2n+2.

5. Hydrocarbons are decomposed into smaller hydrocarbons by
a) reforming
b) refining
c) cracking
d) polymerization
Answer: c
Explanation: Hydrocarbons are decomposed into smaller hydrocarbons by cracking while the molecular structure of the straight-run gasoline is changed by reforming.

6. The molecular structure of the straight-run gasoline is changed by
a) reforming
b) refining
c) cracking
d) boiling
Answer: a
Explanation: The molecular structure of the straight-run gasoline is changed by reforming and hydrocarbons are decomposed into smaller hydrocarbons by cracking.

7. For S.I. engines fuel most preferred are
a) aromatics
b) paraffins
c) olefins
d) napthenes
Answer: a
Explanation: For S.I. engines fuel most preferred are aromatics while for C.I. engines fuel most preferred are paraffins.

8. For C.I. engines fuel most preferred are
a) aromatics
b) paraffins
c) olefins
d) napthenes
Answer: b
Explanation: For C.I. engines fuel most preferred are paraffins and for S.I. engines fuel most preferred are aromatics.

9. In spark ignition engines, the knocking tendency can be decreased by
a) decreasing compression ratio
b) controlling intake throttle
c) controlling ignition timing
d) adding dopes like tetraethyl lead and ethylene dibromide
Answer: d
Explanation: None.

10. Detonation in petrol engines can be suppressed or reduced by the addition of small quantity of
a) lead nitrate
b) iso-octane
c) n-heptane
d) none of the mentioned
Answer: a
Explanation: None.

11. The ECU in the electronic control system, receives signals from the sensors and determines the opening time for the injectors land which also controls the injection volume.
a) True
b) False
Answer: a
Explanation: None.

12. When the engine is cold, the starting of the engine is usually not ___________
a) difficult
b) easy
c) all of the mentioned
d) none of the mentioned
Answer: b
Explanation: The starting of the engine is usually not easy when the engine is cold.

13. When a cold engine is started, it requires a _____________ mixture.
a) leaner
b) richer
c) chemically equal
d) none of the mentioned
Answer: b
Explanation: For starting a cold engine, generally a richer mixture is required.

14. The cold start injector is a type of solenoid valve to which power is supplied from a battery for the opening and closing of the valve inside, thus for injecting the fuel.
a) True
b) False
Answer: a
Explanation: None.

15. The duration of injection time is controlled by a timing switch.
a) True
b) False
Answer: a
Explanation: None.

16. The ignition switch is composed of a bi-metal element and an electric heater coil.
a) True
b) False
Answer: b
Explanation: No, but in fact, the timing switch is composed of a bi-metal element and an electric heater coil.

17. As the temperature is low, the _____________ valve speeds up the engine idle speed to fast idling.
a) nozzle
b) throttle
c) air
d) none of the mentioned
Answer: c
Explanation: At low temperature, the air valve speeds up the engine idle speed to fast idling and not the throttle or nozzle.

18. When the engine is cold, the _____________ plate will be in closed position.
a) nozzle
b) throttle
c) air
d) none of the mentioned
Answer: b
Explanation: Generally, when the engine is cold, the throttle plate will be in closed position and at low temperature, the air valve speeds up the engine idle speed to fast idling.

19. When the engine reaches the normal operating temperature, the valve closes completely and the air flow is cut-off from the _____________ valve.
a) nozzle
b) throttle
c) air
d) none of the mentioned
Answer: c
Explanation: Generally, when the engine reaches the normal operating temperature, the valve closes completely and the air flow is cut-off from the air valve.

20. A thermo wax valve operates depending on the temperature of the engine coolant.
a) True
b) False
Answer: a
Explanation: None.

21. The electronic fuel injection, eliminates majority of carburettor pressure loses and almost eliminates the requirement of manifold heating.
a) True
b) False
Answer: a
Explanation: None.

22. Manifold _____________ is eliminated due to the fuel being injected into or close to the cylinder and need not flow through the manifold.
a) heating
b) wetting
c) cooling
d) none of the mentioned
Answer: b
Explanation: Generally, manifold wetting is eliminated due to the fuel being injected into or close to the cylinder and need not flow through the manifold and not heating or cooling.

23. _____________ of fuel is independent of cranking speed and therefore starting will be easier.
a) Ignition
b) Atomization
c) Condensation
d) None of the mentioned
Answer: b
Explanation: Atomization of fuel is independent of cranking speed and therefore starting will be easier and ignition and condensation are not related to cranking speed.

24. Better atomization and _____________ will make the engine less knock prone.
a) ignition
b) vapourization
c) condensation
d) none of the mentioned
Answer: b
Explanation: Engine knock is dependent on poor atomization and vapourization conditions, so better atomization and vapourization will make the engine less knock prone.

25. Formation of ice on the _____________ plate is eliminated in electronic fuel injection.
a) throttle
b) nozzle
c) engine
d) none of the mentioned
Answer: a
Explanation: Generally, the formation of ice on the throttle plate is eliminated in electronic fuel injection and not of nozzle.

26. In an electronic fuel injection, variation of air-fuel ratio is almost negligible even when the vehicle takes different positions like turning, moving on gradients, uneven roads, etc.
a) True
b) False
Answer: a
Explanation: None.

27. In an electronic fuel injection, position of the injection unit is critical.
a) True
b) False
Answer: b
Explanation: No, in fact, in electronic fuel injection, position of the injection unit is not so critical and thereby the height of the engine can be less.

28. In an electronic fuel injection, the maintenance cost is?
a) low
b) high
c) nil
d) none of the mentioned
Answer: b
Explanation: Generally, in electronic fuel injection, the maintenance cost is high.

29. In an electronic fuel injection, the servicing is very ___________
a) difficult
b) easy
c) nil
d) none of the mentioned
Answer: a
Explanation: The servicing is very difficult in electronic fuel injection.

30. In an electronic fuel injection, there is a possibility of malfunctioning of some sensors.
a) True
b) False
Answer: a
Explanation: None.

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