I.C.

ENGINES

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

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

The calorific value of gaseous fuels is expressed in terms of________________?

A. kcal
B. kcal/kg
C. kcal/m2
D. kcal/m²
E. all of the above

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
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

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

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

The maximum temperature in the I.C. engine cylinder is of the order of ________?

A. 50- 1000°C
B. 1000- 1500°C
C. 1500-2000°C
D. 2000-2500°C
E. 2500-3000°C
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

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

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

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°

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

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

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

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

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
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

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 deac center
D. may start and end anywhere
E. none of the above

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

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
A heat engine utilizes 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

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

The term scavenging is generally associated with______________________?

A. 2-stroke cycle engines

B. 4-stroke cycle engines
C. aero plane engines
D. diesel engines
E. high efficiency engines

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

Most high speed compression engines operate on ___________________?

A. Otto cycle
B. Diesel cycle
C. Dual cycle
D. Carnot cycle
E. Two stroke cycle

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

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

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

The magneto in an automobile is basically__________________?

C. transformer
B. d.c. generator
C. capacitor
D. magnetic circuit
E. a.c. generator
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

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

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

Scavenging is usually done to increase__________________?

A. thermal efficiency
B. speed
C. power output
D. fuel consumption
E. all of the above
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

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

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

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
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

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

A diesel engine has_________________?

A. 1 valve
B. 2 valves
C. 3 valves
D. 4 valves
E. no valve

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. cannot work as it is impossible
D. flywheel size is proper
E. engine cooling is stopped
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

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

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

Does the supply of scavenging air at a density greater than that of atmosphere
mean engine is super charged?

A. yes
B. no
C. to some extent
D. unpredictable
E. depends on other factors
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

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

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

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
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

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°.

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

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%.
The thermal efficiency 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

Combustion in compression ignition engines is____________________?

A. homogeneous
B. heterogeneous
C. both A. and B.
D. laminar
E. turbulent

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

Compression loss in I.C engines occurs due to_________________?

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
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

The air requirement of a petrol engine during starting compared to theoretical air
enquired for complete combustion is___________________?

A. more
B. loss
C. same
D. may be more or less depending on engine capacity
E. unpredictable

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

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
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

The process of breaking up or a liquid into fine droplets by spraying is called___?

A. vaporization
B. carburetion
C. ionization
D. injection
E. atomization

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.

The air-fuel ratio of the petrol engine is controlled by__________________?

A. fuel pump
B. governor
C. injector
D. carburetor
E. scavenging
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

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

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

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
Polymerization is a chemical process in which molecules of a compound
become________________?

A. larger
B. slowed down
C. smaller
D. liquid
E. gaseous

In diesel engine, the compression ratio in comparison to expansion ratio is____?

A. same
B. less
C. more
D. variable
E. more/less depending on engine capacity.

Engine pistons ‘are usually made of aluminum alloy because it_____________?

A. is lighter
B. wears less
C. absorbs shocks
D. is stronger
E. does not react with fuel and lub oil

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
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

Excess quantities of sulphur in diesel fuel are Objectionable because it may

cause the following______________?

Which of the following is false statement?

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

The fuel air ratio in a petrol engine fitted with suction carburetor, 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

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
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

Supercharging is essential in_____________?

A. diesel engines
B. gas turbines
C. petrol engines
D. aircraft engines
E. marine engines

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

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
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%.

Which of the following is the lightest and most volatile liquid fuel____________?

A. diesel
B. kerosene
C. fuel oil
D. gasoline
E. lub oil

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

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
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

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

Which is more viscous lub oil_________________?

A. SEA 30
B. SAE 4£
C. SAE 50
D. SAE 70
E. SAE 80

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
In loop scavenging, the top of the piston is________________?

A. flat
B. contoured
C. slanted
D. depressed
E. convex shaped

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

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

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

In order to prevent formation of carbon on the injector, the temperature of nozzle

tip should be__________________?

A. less than 100°C

B. between 100-250°C
C. between 250 – 300°C
D. between 400 – 500°C
E. between 500 – 1000°C

Ignition quality of petrol is expressed by___________________?

A. octane number
B. cetane number
C. calorific value
D. self ignition temperature
E. distillation temperature

Kerosene is distilled at________________?

A. 30 – 65°C
B. 65 – 220°C
C. 220 – 350°C
D. 350 – 450°C
E. 450-550°C

Iso-oct ,ne________________?

A. has octane number of 0

B. has octane number of 50
C. has octane number of 100
D. is an index of detonation quality
E. is an index of knocking quality

Cetane___________________?

A. has zero cetane number

B. has 100 cetane number
C. helps detonation
D. is a straight chain paraffin
E. determines the efficiency of an I.C. engine
The self-ignition temperature of diesel oil compared to petrol is______________?

A. higher
B. lower
C. same
D. depends on quality of fuel
E. unpredictable

Cetane number is determined by comparing the performance of diesel oil with the
following hydrocarbons___________________?

A. cetane
B. mixture of cetane and alphamethyl napthalene
C. ethylene dibromide
D. mixture of aldehydes and ketones
E. mixture of cetane with tetra-ethyl lead

Violent sound pulsations within the cylinder of an I.C. engine are caused due
to_________________?

A. heavy turbulence
B. improved scavenging
C. heavy supercharging
D. detonation
E. resignation

Ignition lag is__________________?

A. the time taken by fuel after injection (before top dead center) to reach upto
auto-ignition temperature
B. time before actual fuel injection and the pump plunger starts to pump fuel
C. time corresponding to actual injection and top dead center
D. time corresponding to actual ignition and top dead center
E. none of the above
Which is correct statement about reaction time for auto ignition of fuel and the
fuel air ratio__________________?

A. lean mixture has high reaction time

B. rich mixture has high reaction time
C. chemically correct mixture has mini-mum reaction time
D. all of the above
E. non of the above

Normal heptane_______________?

A. accelerates auto-ignition
B. helps to resist auto-ignition
C. does not affect auto-ignition
D. has no relation with auto-ighition
E. retards auto-ignition

Ethyl fluid is used_______________________?

A. to increase the octane rating of the fuel

B. to increase the cetane rating of the fuel
C. as a defrosting agent
D. as a superior type of fluid compared to others
E. to improve lubricating quality of fuel

Octane number is determined by comparing the performance of the petrol with

the following hydrocarbons__________________?

A. iso-octane
B. mixture of normal heptane and iso-oc-tane
C. alpha methyl napthalene
D. mixture of methane and ethane
E. mixture of paraffins and aromatics
Self-ignition temperature of petrol is of the order of___________________?

A. 150°C
B. 240°C
C. 370°C
D. 450°C
E. more than 500°C.

Petrol is distilled at a temperature in range of__________________?

A. 30 – 65°C
B. 65 – 220°C
C. 220-350°C
D. 350-450°C
E. 450-550°C

Auto-ignition temperature 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. that 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. indicated by 50% distillation temperature

The delay period in petrol engine is of the order of__________________?

A. 0.001 sec
B. 0.002 see
C. 0.01 sec
D. 0.05 sec
E. 0.1 sec
The spark plug gap is normally maintained at________________?

A. 0.1 to 0.2 mm
B. 0.2 to 0.4 mm
C. 0.45 to 0.6 mm
D. 0.6 to 0.8 mm
E. 0.8 to 1 mm

The thermal efficiency of a petrol engine of two stroke with crank case
scavenging as compared to four stroke petrol engine with same compression
ratio will be_____________________?

A. higher
B. lower
C. same
D. depends on size of engine
E. unpredictable.

The function of a fuel pump in a petrol pump is to______________________?

A. inject fuel in cylinder

B. supply fuel when carburetor fails
C. pump fuel so that it reaches carburetor (to improve thermal efficiency)
D. does not exist

Detonation is caused by the following unstable compounds_________________?

A. peroxides, aldehydes and ketones

B. peroxides, aldehydes, oxides and sul-phides
C. aldehydes, oxides and ketones
D. ketones and sulphur compounds
E. none of the above

Which is false statement about advantages of V-type engine_________________?

A. compact design requiring lesser space

B. improved distribution of air to cylinder
C. casting less liable to distortion
D. reduced torsional vibration because of shorter crankshaft
E. less overhead clearance

Piston rings are usually made of___________________?

A. cast iron
B. aluminum
C. phosphor bronze
D. Babbitt
E. carbon steel

The top piston ring nearer to the piston crown is known as________________?

A. compression ring
B. oil ring
C. scrapper ring
D. groove ring
E. leading ring

If overhead clearance is less, then the following type of engine should be

selected__________________?

A. V-type
B. In-line
C. Vertical
D. Horizontal
E. Radial

The pistons are usually given a coating such as tin plating in order to_________?

A. reduce weight
B. conduct heat efficiently
C. reduce possibility of scoring
D. reduce friction
E. increase lubrication effect
Piston rings are plated with chromium, cadmium or phosphate in order to______?

A. reduce cost
B. improve surface finish
C. prevent clogging
D. reduce wear and eliminate scuffing
E. improve heat transfer

To reduce the possibility of knock in the C.I. engines, the first elements of fuel
and air should have_______________?

A. high temperature
B. high density
C. short delay
D. reactive mixture
E. all of the above

In order to prevent knock in the S.I. engines, the charge away from the spark plug
should have___________________?

A. low temperature
B. low density
C. long ignition delay
D. rich mixture
E. all of the above

Diesel engines have low specific fuel consumption compared to petrol engine.
This statement is____________________?

A. not true
B. true at full load
C. true at part load
D. true at both part and full load
E. there could not be any such criterion
Carbon residue in diesel oil should not be more than___________________?

A. 1%
B. 0.5%
C. 0.1%
D. 0.01%
E. 0.001%

Injection lag is_________________?

A. the time taken by fuel after injection (before top dead center) to reach upto auto-
ignition temperature
B. time before actual fuel injection and the pump pluger starts to pump fuel
C. time corresponding to actual injection and top dead center
D. time corresponding to actual ignition and top dead center
E. none of the above

The knocking in diesel engines for given fuel, will be__________________?

A. enhanced by increasing compression ratio

B. enhanced by decreasing compression ratio
C. unaffected by compression ratio
D. first enhanced by increasing compression ratio upto a limit beyond which it will be
suppressed
E. dependent on other factors

According to Ricardo’s theory, detonation occurs due to___________________?

A. instantaneous auto-ignition of last part of charge to be burnt

B. improper mixing of air and fuel
C. improper combustion
D. self ignition temperature has nothing to do with detonation
E. none of the above
The ignition of charge by some hot surface in the engine cylinder before
operation of spark plug is known as________________?

A. auto ignition
B. preignition
C. retarded ignition
D. accelerated ignition
E. detonation

Ignition quality of diesel-fuel oil is expressed by an index called_____________?

A. octane number
B. cetane number
C. calorific value
D. carbon content
E. ignition temperature

The compression ratio of motor cars is___________________?

A. 5
B. 7
C. 10
D. 13
E. 16

Freezing temperature of petrol is usually__________________?

A. 0°C
B. – 10°C
C. 10°C
D. less than – 30°C
E. less than – 273°C
The most popular firing order in case of four cylinder in-line I.C. engine is______?

A. 1-2-3-4
B. 1-3-2-4
C. 1-4-2-3
D. 1-2-4-3
E. 1-3-4-

The specific gravity of diesel oil Is_________________?

A. 1
B. 0.7
C. 0.85
D. 0.5
E. 1.25

Detonation can be controlled by_____________________?

A. varying compression ratio

B. using lian mixture
C. retarding the spark timing
D. reducing the r.p.m.
E. increasing inlet pressure

The m.e.p. of a diesel cycle having fixed compression ratio with increase in cut-
off will_________________?

A. increase
B. decrease
C. be unaffected
D. depend on other factors
E. unpredictable
The firing order in a six stroke I.C. engine is_________________?

A. 1-3-6-5-2-4
B. 1-4-2-5-6-3
C. 1-6-2-5-4-3
D. 1-5-2-6-3-4
E. 1-5-3-4-2-6

The efficiency of I.C. engines normally is of the order of_________________?

A. 15-20%
B. 20-25%
C. 25-30%
D. 30-35%
E. 35-50%

Sulphur content in diesel oil should not be more than_________________?

A. 10%
B. 5%
C. 1%
D. 0.1%
E. 0.01%

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

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

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

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

A fuel will detonate less if it has___________________?

A. higher self ignition temperature

B. lower self-ignition temperature
C. proper self-ignition temperature
D. self-ignition temperature has nothing to do with detonation
E. none of the above

The ash content in diesel oil should not be more than_______________?

A. 1%
B. 5%
C. 0.1%
D. 0.01%
E. 0.001%
Fuel consumption with increase in back pressure will________________?

A. increase
B. decrease
C. remain unaffected
D. depend on other factors
E. none of the above

A 4-stroke diesel engine needs about following amount of air_______________?

A. 75 cc per min. per h.p.

B. 750 cc per min. per h.p.
C. 7500 cc per min. per h.p.
D. 75000 cc per min. per h.p.
E. 750000 cc per min. per h.p

With increase in speed of vehicle, the back pressure will________________?

A. decrease
B. increase
C. remain unaffected
D. depend on other factors
E. none of the above

Air injection in I.C. engines refers to injection of___________________?

A. air only
B. liquid fuel only
C. liquid fuel and air
D. supercharging
E. does not exist

The ratio of useful power; engine friction exhaust gas losses; cooling water, air
and oil losses for a diesel engine is of the order of____________________?

A. 5:25:30:50
B. 25:35:5:35
C. 25:5:10:60
D. 40:30:15:15
E. 25:5:35:35

The system of lubrication used for motor cycles and scooters is by__________?

A. forced lubrication system

B. splash lubrication
C. applying grease under pressure
D. wet sump method
E. mixing about 5% lub oil with petrol

The specific fuel consumption for a petrol engine first decreases with increase in
fuel air ratio and then increases with further increase in fuel air ratio. The
minimum value occurs in the range of__________________?

A. lean mixture
B. chemically correct mixture
C. rich mixture
D. unpredictable
E. none of the above

Diesel engines as compared to petrol engines require ______________________?

A. bigger flywheel
B. smaller flywheel
C. same size flywheel
D. no flywheel
E. flywheel whose size may be less or more depending on several other fac-tors

Auto-ignition reaction time for petrol engine first decreases with increase in fuel
air ratio, reaches a minimum value and then increases with subsequent increase
in fuel air ratio. The minimum value occurs in the region of________________?

A. Lean mixture
B. Chemically correct fuel air ratio
C. Rich mixture
D. Unpredictable
Exhaust pipes of engines are covered with insulating material in order to______?

A. keep the exhaust pipes warm

B. reduce formation of condensate
C. reduce heat transfer to the engine room
D. increase engine efficiency
E. conserve heat

The thermal efficiency of a two cycle engine as compared to four cycle engine
is_________?

A. more
B. less
C. same
D. more upto some load and then less
E. it may be less or more depending on several other factors

The m.e.p. of a petrol engine first increases as the fuel air ratio is increased and
then decreases on further increase in fuel air ratio. The M.E.P is maximum in the
zone of________________?

A. lean mixture
B. chemically correct mixture
C. rich mixture
D. unpredictable
E. none of the above

Solid injection in I.C. engines refers to injection of________________?

A. liquid fuel only

B. liquid fuel and air
C. solid fuel
D. solid fuel and air
E. does not exist
For same power and same speed, the flywheel of a four stroke engine as
compared to two-stroke I.C. engine will be________________?

A. smaller
B. bigger
C. same size
D. dependent on other engine parameters
E. unpredictable

The function of a distributor in an automobile is to__________________?

A. distribute charge, equally to all the cylinders

B. regulate power
C. feed lub oil to all moving parts
D. time the spark
E. inject fuel at appropriate time

Leakage past the piston rings and valve seats in I.C. engines with increase in
speed_______________?

A. increases.
B. decreases
C. remains same
D. unpredictable
E. none of the above

The cooling water requirement for diesel engine is of the order of____________?

A. 0.2 to 1.0 liter per minute per h.p.

B. 1 to 3 liters per minute per h.p.
C. 5 to 10 liters per minute per h.p
D. 10 to 20 liters per minute per h.p.
E. 20-30 liters per minute per h.p
Ignition timing of a multi cylinder petrol engine can be adjusted by____________?

A. rotating the crank

B. adjusting the spark plug gap
C. adjusting ignition coil position
D. rotating the distributor
E. delaying the spark by increasing capacitor in ignition circuit

High carbon content in diesel oil used for diesel engine leads to_____________?

A. production of highly corrosive gases corroding the cylinder walls and exhaust system
B. excessive engine wear
C. damaging of both the storage tank and the engine
D. deposition on engine parts
E. none of the above.

The pour point of diesel oil must be_________________?

A. lower than the coldest atmospheric temperature at which oil is to be pumped

B. higher than above
C. has no such relation
D. more than 100°C
E. none of the above

In petrol engine, increase of cooling water temperature will_________________?

A. increase the knocking tendency

B. decrease the knocking tendency
C. not affect the knocking tendency
D. increase or decrease knocking tendency depending on strength and time of spark
E. unpredictable
In petrol engines, the maximum power is developed corresponding to relative fuel
air ratio of________________?

A. 0.85
B. 1
C. 1.1 to 1.3
D. 1.2 to 1.5

In carburetors, the top of the fuel jet with reference to the level in the float
chamber is kept at_________________?

A. same level
B. slightly higher level
C. slightly lower level
D. may be anywhere
E. varies from situation to situation

Power impulses from an I.C. engine are somoothed out by__________________?

A. governor
B. crank shaft
C. gear box
D. flywheel
E. timing spark properly

For low speed operation or for idling in petrol engines, the engine requirements
are for_______________?

A. lean mixture
B. theoretically correct mixture
C. rich mixture
D. any type of mixture
E. lean/rich mixture depending upon capacity of engine
The essential equipment for producing high vlotage for sparking in petrol engines
with battery is_______________?

A. ignition coil
B. ignition coil and distributor
C. ignition coil and condenser
D. ignition coil and contact breaker
E. ignition coil, contact breaker and con-denser

In petrol engines, advancing the spark timing will_______________?

A. increase the knocking tendency

B. decrease the knocking tendency
C. not affect the knocking tendncy
D. increase or decrease knocking tendency depending on strenght and time of spark
E. unpredictable

The ignition coil in diesel engines produces voltage of the order of___________?

A. 6 to 12 volts
B. 240 volts
C. 1000 volts
D. 20,000 volts
E. 80,000 volts

The thermal efficiency of a diesel engine is of the order of_________________?

A. 92%
B. 68%
C. 52%
D. 34%
E. 25%.
Theoretically, the following engine should have maximum efficiency_________?

A. gas engine
B. 2-stroke S.I. engine
C. 4-stroke S.I. engine
D. steam engine
E. 4-stroke C.I. engine

In petrol engine using a fixed octane rating fuel and fixed compression ratio,
super charging will_________________?

A. increase the knocking tendency

B. decrease the knocking tendency
C. not affect the knocking tendency
D. increase or decrease knocking tendency depending on strength and time of spark
E. unpredictable

In open combustion chamber in diesel engines____________________?

A. the shape and layout of the piston crown, the inlet port, and the valve produce
the turbulent effect on fuel mixture
B. fuel is injected into an auxiliary chamber that is separated from the cylinder by an
orifice or throat
C. only a part of air charge is contained in an auxiliary chamber in which the fuel starts
to burn with insufficient air which due to explosion tendency mixes thoroughly into main
cylinder charge
D. fuel is injected at atmospheric pres¬sure
E. there are no valves.

Which of the following engines can work on very lean mixture_______________?

A. S.I. engine
B. C.I. engine
C. two stroke engine
D. four stroke engine
E. all of the above
Hot air standard diesel cycle efficiency with increase in value of C„__________?

A. increases
B. decreases
C. remains unaffected
D. depends on other factors
E. unpredictable

For low load operation, more suitable (economical) engine is_______________?

A. S.I. engine
B. C.I. engine
C. both are equally good
D. multi cylinder engine
E. two stroke engine

For the same size and weight, a two stroke engine as compared to four stroke
engine will generate power_________________?

A. about twice
B. about 0.5 times
C. nearly equal
D. about 1.7 times
E. about 5 times

If diesel is fed by mistake in the oil tank of a petrol engine, then engine will_____?

A. give lot of smoke

B. detonate
C. knock
D. not run
E. run for some time and then stop
An engine has a normal speed of 960 r.p.m. and no load speed of 1000 r.p.m. The
speed drop of governor will be about___________________?

A. 2%
B. 4%
C. 8%
D. ±4%
E. 1%.

In isochronous governing, speed droop is_______________?

A. 100%
B. 50%
C. 5%
C. 30%
E. 1%.

Method of governing used in diesel engine is__________________?

A. quantity governing
B. quality governing
C. combined governing
D. partial governing
E. nit and miss governing

Method of governing used in petrol engine is________________?

A. quantity governing
B. quality governing
C. combined governing
D. partial governing
E. hit and miss governing
The thermal efficiency of a petrol engine at design load is around____________?

A. 90%
B. 50%
C. 40%
D. 30%
E. 15%.

As the number of cylinders in multi-cylinder engine increases, the power to

weight ratio_______________?

A. Decreases
B. Increases
C. Remains same
D. Decreases upto a limit and then increases

All the four operations in two stroke engine are performed in following number of
revolutions of crank shaft______________________?

A. Half
B. One
C. Two
D. Four

In the case of petrol engine at maximum output, the percentage of CO in exhaust

gases is ____________________?

A. Zero
B. 5-10%
C. Depends on load and quality of fuel
D. Considerable percent

In a diesel engine, injection pressure developed by injector is of the order of___?

A. 10 kg/cm2
B. 100 kg/cm2
C. 500 kg/cm2
D. 1400 kg/cm2
In pre combustion chamber in diesel engine________________?

A. The shape and layout of the piston crown, the inlet port, and the valve produce the
turbulent effect of fuel mixture
B. Fuel is injected into an auxiliary chamber that is separated from the cylinder by an
orifice or throat
C. Only a part of air charge is contained in an auxiliary chamber in which the fuel
starts to burn with insufficient air which due to explosion tendency mixes
thoroughly into main cylinder charge
D. There are no valves

The thermal efficiency of a semi-diesel cycle having fixed compression ratio and
fixed quantity of heat, with increase in pressure ratio will_______________?

A. increase
B. decrease
C. remain unaffected
D. increase/decrease depending upon engine capacity
E. first increase and then decrease

In the case of compression ignition engine, the %age of CO in exhaust gases is_?

A. Zero
B. 5-10%
C. Depends on load
D. Considerable percent

A two stroke engine is usually identified by__________________?

A. size of flywheel
B. weight of engine
C. type of lubrication system
D. absence of valves
E. location of fuel tank
A two stroke crank compressed engine has following ports in the cylinder____?

A. suction port and exhaust port

B. transfer port only
C. suction port and transfer port
D. transfer port and exhaust port
E. suction port, exhaust port and transfer port

Scavenging air is supplied to a two-stroke engine at a density greater than that of

atmosphere. This means the engine is__________________?

A. Supercharged
B. Not supercharged
C. Charged
D. Supercharged provided its speed is low

In turbulence chamber in diesel engine__________________?

A. the shape and layout of the piston crown, the inlet port, and the valve produce the
turbulent effect of fuel mixture
B. fuel is injected into an auxiliary chamber that is separated from the cylinder by
an orifice or throat
C. only a part of air charge is contained in an auxiliary chamber in which the fuel starts
to burn with insufficient air which due to explosion tendency mixes thoroughly into main
cylinder charge
D. there are no valves
E. fuel is partly burnt by spark

If petrol is used in a diesel engine then______________?

A. higher knocking will occur

B. efficiency will be low
C. low power will be produced
D. black smoke will be produced
E. lot of fuel will remain unburnt
Deposition of carbon in petrol engine cylinder would result in increase of_____?

A. clearance volume
B. swept volume
C. compression ratio
D. volumetric efficiency
E. mean effective pressure

The part load efficiency of a carburetor is,___________________?

A. Maximum
B. Optimum
C. Poor
D. Constant

The basic requirement of a good combustion chamber is___________________?

A. high compression ratio

B. low compression ratio
C. low volumetric efficiency
D. minimum turbulence
E. high power output and high thermal efficiency

The following type of carburetor is preferred_______________?

A. concentric type
B. eccentric type
C. horizontal type
D. vertical type
E. none of the above

The theoretically correct mixture of air and petrol is approximately __________?

A. 0.334027778
B. 0.500694444
C. 0.625694444
D. 0.834027778
Carburetion is done to________________?

A. feed petrol into cylinder

B. govern the engine
C. break up and mix the petrol with air
D. heat up the charge to cylinder
E. scavenge the cylinder

With increase in engine speed, the ignition of spark in petrol engine has to be
_________________?

A. Unaltered
B. Increased
C. Decreased
D. Advanced

Pick up false statement?

A. For petrol and large gas engines, quantity governing preferred

B. In quantity governing, air fuel ratio is almost constant and quantity of charge is
changed depending on load
C. In hit and miss governing, fuel supply is completely cut off during one or more
number of cycles
D. In quality governing, quantity of fuel is varied to suit the load and total charge
of air is varied
E. For close regulation of speed, combination of both quality and quantity governing is
used

Diesel Cycle is also known as : __________?

A. Constant temperature cycle

B. Constant Volume cycle
C. Constant Pressure Cycle
D. All of above
The efficiency of the ideal diesel cycle is ________ than that of Otto cycle, for the
same compression ratio

A. Higher
B. Lower
C. Equal
D. None of these

The natural solid fuels are : ________?

A. Wood
B. Peat
C. Lignite
D. All of above

The average calorific value of wood is about : __________?

A. 33500 kj/kg
B. 25000 kj/kg
C. 23000 kj/kg
D. 19700 kj/kg

Which of the following solid fuel has high caloric value : ___________?

A. Wood
B. Peat
C. Bituminous coal
D. Anthracite coal

Which of the following is mostly used as blast furnace fuel for extracting pig iron
from iron ores?

A. Brown coal
B. Anthracite coal
C. Hard coke
D. Wood char coal
The patrol is distilled at a temperature from :

A. 6° to 20°
B. 220° to 345°
C. 65° to 220°
D. 15° to 120°