Internal Combustion Engines (I.C. Engines) MCQ

Test your knowledge with important Internal Combustion Engines (I.C. Engines) MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30 + more Internal Combustion Engines (I.C. Engines) MCQs at Bissoy

• The knocking in diesel engines may be prevented by
  ক

  Reducing the delay period

  খ

  Raising the compression ratio

  গ

  Increasing the inlet pressure of air

  ঘ

  All of these
• The knocking tendency in spark ignition engines may be decreased by
  ক

  Controlling the air-fuel mixture

  খ

  Controlling the ignition timing

  গ

  Controlling the exhaust temperature

  ঘ

  Reducing the compression ratio
• The term scavenging is generally associated with
  ক

  2-stroke cycle engines

  খ

  4-stroke cycle engines

  গ

  Aeroplane engines

  ঘ

  High efficiency engines
• A fuel of cetane number 40 has the same ignition quality as a mixture of
  ক

  40% cetane and 60% alpha methyl naphthalene

  খ

  40% alpha methyl naphthalene and 60% cetane

  গ

  40% petrol and 60% diesel

  ঘ

  40% diesel and 60% petrol
• A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of
  ক

  75% iso-octane and 25% normal heptane

  খ

  75% normal heptane and 25% iso-octane

  গ

  75% petrol and 25% diesel

  ঘ

  75% diesel and 25% petrol
• In diesel engine, the compression ratio in comparison to expansion ratio is
  ক

  Same

  খ

  Less

  গ

  More

  ঘ

  Variable
• The sensing element in the control system of nuclear reactors measures the _________ of the neutron flux in the reactor.
  ক

  Temperature

  খ

  Volume

  গ

  Density

  ঘ

  None of these
• The reflectivity depends upon
  ক

  Geometry of the reflector

  খ

  Energy of neutrons

  গ

  Properties of the reflector

  ঘ

  All of these
• Which is more viscous lube oil?
  ক

  SEA 30

  খ

  SAE 50

  গ

  SAE 70

  ঘ

  SAE 80
• The thermal efficiency of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will
  ক

  Increase

  খ

  Decrease

  গ

  Be independent

  ঘ

  May increase or decrease depending on other factors
• Crankcase explosion in I.C. engines usually occurs as
  ক

  First a mild explosion followed by a bi explosion

  খ

  First a big explosion followed by a mil explosion

  গ

  Both mild and big explosions occurs simultaneously

  ঘ

  Never occurs
• The basic requirement of a good combustion chamber is
  ক

  Minimum turbulence

  খ

  Low compression ratio

  গ

  High thermal efficiency and power output

  ঘ

  Low volumetric efficiency
• Which of the following is false statement? <br>Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the following
  ক

  Piston ring and cylinder wear

  খ

  Formation of hard coating on piston skirts

  গ

  Oil sludge in the engine crank case

  ঘ

  Detonation
• If V₁ is the jet velocity and V₀ is the vehicle velocity, then propulsive efficiency of a turbojet engine is
  ক

  $$\frac{{{{\text{V}}_1}}}{{{{\text{V}}_0} + {{\text{V}}_1}}}$$

  খ

  $$\frac{{{{\text{V}}_0}}}{{{{\text{V}}_0} + {{\text{V}}_1}}}$$

  গ

  $$\frac{{2{{\text{V}}_0}}}{{{{\text{V}}_0} + {{\text{V}}_1}}}$$

  ঘ

  $$\frac{{2{{\text{V}}_1}}}{{{{\text{V}}_0} + {{\text{V}}_1}}}$$
• The accumulation of carbon in a cylinder results in increase of
  ক

  Clearance volume

  খ

  Volumetric efficiency

  গ

  Ignition time

  ঘ

  Effective compression ratio
• The mean effective pressure obtained from engine indicator indicates the
  ক

  Maximum pressure developed

  খ

  Minimum pressure

  গ

  Instantaneous pressure at any instant

  ঘ

  Average pressure
• The thermal efficiency of a petrol engine is _________ as compared to diesel engine.
  ক

  Same

  খ

  Less

  গ

  More

  ঘ

  None of these
• In a diesel engine, the duration between the time of injection and ignition, is known as
  ক

  Pre-ignition period

  খ

  Delay period

  গ

  Period of ignition

  ঘ

  Burning period
• A petrol engine, during suction stroke draws
  ক

  Air only

  খ

  Petrol only

  গ

  A mixture of petrol and air

  ঘ

  None of these
• In a four stroke cycle diesel engine, the exhaust valve
  ক

  Opens at 30° before bottom dead centre and closes at 10° after top dead centre

  খ

  Opens at 30° after bottom dead centre and closes at 10° before top dead centre

  গ

  Opens at bottom dead centre and closes at top dead centre

  ঘ

  May open and close anywhere
• By higher octane number of spark ignition fuel, it is meant that the fuel has
  ক

  Higher heating value

  খ

  Higher flash point

  গ

  Lower volatility

  ঘ

  Longer ignition delay
• If one cylinder of a diesel engine receives more fuel than the others, then for that cylinder the
  ক

  Exhaust will be smoky

  খ

  Piston rings would stick into piston grooves

  গ

  Engine starts overheating

  ঘ

  Scavenging occurs
• The rating of a diesel engine, with increase in air inlet temperature, will
  ক

  Increase linearly

  খ

  Decrease linearly

  গ

  Increase parabolically

  ঘ

  Decrease parabolically
• Gaseous fuel guarantees are based on
  ক

  Calorific value of oil

  খ

  Low heat value of oil

  গ

  High heat value of oil

  ঘ

  Mean heat value of oil
• In case of gas turbines, the gaseous fuel consumption guarantees are based on
  ক

  High heat value

  খ

  Low heat value

  গ

  Net calorific value

  ঘ

  Calorific value
• In a petrol engine, the mixture has the lowest pressure at the
  ক

  Beginning of suction stroke

  খ

  End of suction stroke

  গ

  End of compression stroke

  ঘ

  None of these
• All heat engines utilize
  ক

  Low heat value of oil

  খ

  High heat value of oil

  গ

  Net calorific value of oil

  ঘ

  Calorific value of fuel
• The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to
  ক

  Inject fuel in a chamber of high pressure at the end of compression stroke

  খ

  Inject fuel at a high velocity to facilitate atomization

  গ

  Ensure that penetration is not high

  ঘ

  All of the above
• A higher compression ratio causes
  ক

  Pre-ignition

  খ

  Increase in detonation

  গ

  Acceleration in the rate of combustion

  ঘ

  Any one of these
• As a result of detonation in an I.C. engine, following parameter attains very high value
  ক

  Peak pressure

  খ

  Rate of rise of pressure

  গ

  Rate of rise of temperature

  ঘ

  Peak temperature