MD S-2


MECHANIC DIESEL THEORY
 SEM -2 JAN18

A diesel engine has compression ratio from .......
a) 6 to 10
b) 10 to 15
c) 15 to 25
d) 25 to 40

Sulphur content in diesel oil should not be more than .......
a) 0.10%
b) 1%
c) 0.01%
d) 5%

In two stroke engine, the working cycle is completed in ......
a) One revolution of the crankshaft
b) Two revolutions of the crankshaft
c) Three revolutions of the crankshaft
d) Four revolutions of the crankshaft

Theoretically a four stroke cycle engine should develop ........... power as that of a two  stroke cycle engine,
a) Half
b) Same
c) Double
d) Four times

The spring clamps pressure friction plate between pressure plate and ............ when clutch is engaged.
a) Flywheel
b) Differential
c) Reaction plate
d) Clutch paddle

A two stroke cycle engine gives  ............. thermal efficiency than a four stroke cycle engine.
a) Higher
b) Lower
c) Same
d) None of these

In a four stroke cycle engine, the sequence of operation 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

Due to turbo charger, air intake in a engine ........
a) Decreases
b) Increases
c) Remains same
d) No change

In diesel engine the fuel is injected into the cylinder when the piston is .........
a) Exactly at T.D.C after exhaust stroke
b) Exactly at B.D.C before compression stroke
c) Nearing T.D.C during compression stroke
d) Approaching T.D.C during exhaust stroke

In S.I. engine, Sul. stands for .......
a) Straight Ignition
b) Standard Ignition
c) Spark Ignition
d) None of these

The oil pump is driven by the .....
a) Camshaft
b) Crankshaft directly
c) Camshaft via drive belt
d) Propeller shaft

The motion of the cam is transferred to the valve through ...........
a) Valve stems
b) Camshaft pulley
c) Rocker arms
d) Piston

The function of an alternator in an automobile is to .......
a) Continually recharge the battery
b) Partly convert engine power into electric power
c) Supply electric power
d) Convert mechanical energy into electrical energy

The firing order for an inline four Cylinder l.c engine is ........
a) 1-2-4-3 b) 1-3-4-2
c) 1-2-3-4 d) 1-3-2-4

The odometer is an instrument used for measurement of ........
a) Power
b) Fuel consumption
c) Engine rpm
d) Distance

The connecting rod lower end is connected to the relevant ........... of crankshaft.
a) Big end
b) Crank arm
c) Journal
d) Small end

The condition that results in large quantities of hydrocarbon emission is .........
a) High temperature combustion
b) Incomplete combustion
c) Low temperature combustion
d) High atmospheric temperature combustion

The diagram which shows the correct crank positions corresponding to the opening and   closing of the valve is known as .............
a) Indicator diagram
b) Acid force diagram
c) Valve timing diagram
d) None of these

The starter motor is driven by ......
a) Clutch drive
b) Gear drive
c) Flat belt drive
d) V belt drive

The component in the radiator of an automobile that increases the boiling point of water  is .......
a) Drain plug
b) Water jacket
c) Vacuum valve
d) Pressure cap

In a forced feed lubrication system the device used to guard against excessive oil pressure
is known as ..........
a) Release chamber
b) Balancer
c) Relief valve

The two kind of piston rings are ........
a) Compression rings and oil control rings
c) Oil control rings and oil scraper   d) Stop valve
b) Compression rings and sliding seal rings
d) Pressure and sealingrings

The purpose of a thermostat in an engine cooling system is to .....
a) Prevent the cooling from boiling
b) Allow the engine to warm up quickly
c) Indicate the coolant temperature
d) Pressurise the system to raise the boiling point

A three way catalytic converter is used to.........
a) Re-circulate exhaust gases
b) Burn fuel vapour
c) Reduce nitrogen oxide, hydrocarbon and carbon di-oxide emission levels
d) Remove carbon di-oxide, hydrocarbon and nitrogen oxide from the exhaust gases passing through it

The information provided by the oxygen sensor to the feedback control system is about the .........
a) Air fuel ratio
b) Air temperature
c) Air flow speed
d) Exhaust gas volume

The starting system includes ......
a) A battery, a starter and an ignition switch
b) A battery, a distributor and an ignition switch
c) A battery, a starter and a distributor
d) A distributor, a starter and an ignition switch

The function of a connecting rod is .......
a) To turn the fly wheel
b) To drive the drive plate
c) To drive the fuel pump
d) To transmit motion of the piston to the crankshaft

The basic part of the engine to which the other engine p ts are attached or assembled is   the .......
a) Cylinder head
b) Cranksh
c) Cylinder block
d) Oil pan

The cam shaft in an engine is always mounted ........
a) Parallel to the crankshaft
b) Perpendicular to the crankshaft
c) Inclined to the crankshaft
d) None of these

Which bearing is commonly used in the crankshaft of an automobile engine?
a) Ball bearing
b) Coller bearing
c) Taper roller bearing
d) Thin wall bearing

In a diesel engine, the function of a fuel injector is to ..........
a) Mix the fuel and air
b) Ignite the air- fuel mixture
c) Provide flame front for ignition
d) Spray atomized fuel in the cylinder

One effect of detonation is .....
a) Delay in ignition
b) Loss of power
c) Overheating of an engine
d) Overcooling of an engine

The engine oil is stored in ............. when the engine is not running.
a) Oil pan
b) Cylinder head
c) Oil pump
d) Separate oil tank

Which part does not rotate in the engine?
a) Piston
b) Crankshaft
c) Cylinder head
d) All of these

In the charging system of an Alternator, which of the following is used to convert AC to DC.
a) Slip rings
b) Diodes
c) Regulator
d) Starter

The condition that results in large quantities of carbon monoxide emission is ........
a) Insufficient air during combustion
b) Insufficient fuel during combustion
c) Low temperature combustion
d) High temperature combusting

In a car which of the following bulb will have the least wattage?
a) Head light bulb
b) Stop light bulb
c) Parking light bulb
d) Ignition warning bulb

The function of distributor in an automobile is to .......
a) Distribute charge equally to all the cylinder
b) Regulate power
c) Feed lub oil to all moving parts
d) Time the spark

In the opposed piston diesel engine, the combustion chamber is located ........
a) Above the piston
b) Below the piston
c) Between the piston
d) Anywhere

Which of the following is not a part of common rail diesel injection system?
a) Sensor
b) Injector
c) Air cleaner
d) Actuator

The knocking in diesel engines may be prevented by .........
a) Reducing the delay period
b) Raising the compression ratio
c) Increasing the inlet pressure of air
d) All of these

Which factor contributes to high fuel consumption?
a) Defect in Solenoid switch
b) Discharged batter
c) Clogged air cleaner
d) Weak pressure relief vavle

Lubrication oil consumption is high on a vehicle. Identify the cause ........
a) Breath filler removed
b) Battery is weak
c) Worn out piston rings
d) Alternator not charging

The least flash point of diesel is -
a) 50°F b) 75°F
c) 100°F d) 150°

The function of automobile catalytic converter is to control emission of -
a) Carbon dioxide and hydrogen
b) Carbon monoxide and hydrogen
c) Carbon monoxide and carbon dioxide
d) Carbon monoxide and nitrogen dioxide

The operation of forcing additional air under air pressure into the engine cylinder is   known as ........
a) Supercharging
b) Carburation
c) Turbulence
d) Delay period

Injection pressure in a diesel engine is about  ..........
a) 10 bar b) 100 bar
c) 150 bar d) 500 bar


The crank lubricated through .....
a) Cam shaft bearing
b) Main gallery
c) Drilled oil holes in man journal of crankshaft
d) Connecting rod big end holes

For charging two stroke diesel engines cylinder, one Of the following devices is used .........
a) Turbocharger
b) Roots blower
c) Ram charger
d) Compression gauge

Fuel pumps are generally mounted on ,........
a) F.I.P
b) Fuel filters
c) Fuel tank
d) Cylinder head

July17 MECHANIC (DIESEL) THEORY SEMESTER-II

In which working cycle is completed in four stroke engine?
a) One revolution of the crankshaft
b) Two revolution of the crankshaft
c) Three revolution of the crankshaft
d) Four revolution of the crankshaft

In which parts are to be joined between cylinder head and engine block?
a) Valve guide
b) Compressor ring
c) Combustion chamber
d) Head gasket

A two stroke cycle engine gives the number of power strokes as compared to the four  stroke cycle engine at the same engine speed.
a) Half
b) Same
c) Double  
d) Four times

A two stroke cycle engine gives mechanical efficiency than a four stroke cycle engine-
a) Higher
b) Inwer
c) Same
d) None of these

After fitting rings over piston, it is inserted in cylinder with the help of a special tool called-
a) Ring Expander
b) Ring cleaner
c) Ring compressor
d) Ring groove cleaner

Compression ratio of diesel engine 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) Swept volume/Cylinder volume
d) Cylinder volume/Swept volume
The main function of intake manifold is
a) Reduce intake noise
b) Provide the mixture of air and fuel
c) Distribute intake air equally to the cylinder
d) Cools the intake air to a suitable temperature

The heat transfer from coolant to air in radiator of an automobile engine take place by-
a) Radiation only
b) Convention only
c) Convention & Radiation only
d) Conduction, Convention & Radiation

Water circulation in a radiator take place from
a) Lower tank to upper tank
b) Upper to lower tank
c) Engine to upper tank
d) Engine to water pump

Supercharger is the function 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) Supplying compressed air to remove combustion products only
d) Injecting excess fuel for raising more load

In case of gas turbines, the gaseous fuel consumption guarantees are based on-
a) Low heat value
b) High heat value
c) Calorific value
d) Net calorific value

Engine pistons are usually made of aluminium alloy because it.
a) Is lighter
b) Warless  
c) Absorb shocks
d) Does not react fuel & lubricant oil

Which is more viscous lubricant oil?
a) SAE 30
b) SAE 40
c) SAE 50
d) SAE 80

In the opposed piston diesel engine, the combustion chamber is located -
a) Above the piston
b) Below the piston
c) Between the piston
d) Anywhere

Piston rings are usually made of-
a) Cat iron
b) Cast steel
c) Aluminium
d) Brass

The forced fed lubrication system means that the oil is delivered to the engine by-
a) Gravity b) The pressure created by the oil pump
c) Splashing action of the crankshaft d) None of these

Exhaust pipes of engines are covered with insulating material in order to
a) Keep the exhaust pipes warm b) Increase engine efficiency
c) Reduce heat transfer to engine room
d) Conserve heat

Fuel consumption with increase in "back pressure" will-
a) Increase
b) Decrease
c) Depend on the factor
d) Remain unaffected

In which parts of battery charging rotates crank fan belt?
a) Water pump pulley
b) Dynamo
c) Self Starter
d) Magneto

In order to eliminate knocking in compression ignition engines, there should be-
a) Short delay period
b) Late auto - ignition
c) Low compression ratio
d) High self-ignition temperature of fuel

The most effective air cleaner in case of diesel engine is-
a) Dry type
b) Wet type
c) Whirl type
d) Oil bath type

Preferred location of an oil cooler is-
a) Before the filters
b) After the filters
c) Between the filters
d) Anywhere

High sulphur content in diesel oil used for diesel engines lead 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) Reduction in thermal efficiency

The device used to reduce exhaust noise is called
a) Muffler
b) Exhaust pipe
c) Exhaust manifold
d) Tail pipe

The device for smoothing out the power impulses from the engine is called
a) Flywheel
b. Camshaft
c. Crankshaft
d. Clutch

Coolant temperature sensor is a thermostat or give information of temperature to
a) Fuel tank
b) Injection pump
c) E.C.M
d) Injector

Actually engine speed sensor indicates position of the
a) Camshaft
b) Crankshaft
c) Valve
d) Piston

Oxygen sensor is mounted on

a) Exhaust manifold
b) Intake manifold
c) Both a & b
d) None of these

Actuator is a type of sources..  .
a) Electro mechanic
b) Hydraulic
c) Only mechanical
d) Only chemical

In charging system - Alternator, which of the following is used to convert AC to DC in  Alternator-
a) Slip rings
b) Diodes
c) Regulator
d) Starter

Clutch assembly are fitted with
a) Piston
b) Crankshaft
c) Gear box  
d) Flywheel

Which method is used for oil supply to  parts after filter?
a) Splash system
b) Full flow lubrication system
c) Splash cum pump method 
d) Fly wheel splash method

If thermostat valve is closed, what will happen?
a) Engine do not run
b) Engine become hot gradually
c) Engine become vibrate.
d) Enginc bccomc very hot

Injection pressure in a diesel engine is about-
a) 10 bar
b) 100 bar
c) 150 bar
d) 500 bar

Which type of bearing is used for main bearing and connecting rod bearing?
a) Ball bearing
b) Needle roller bearing
c) Plain bearing
d) Taper roller bearing

Starter Motor, the engine crankshaft must be rotated at a speed of 100 rpm to start the engine. What is possible cause of the pinion disengages slowly after starting?
a) Weak battery
b) Over running clutch defective
c) Open in control circuit
d) Open circuit in commutator

The Firing order in an l.c Engine depend upon -
a) Arrangement of cylinder
b) Design of crankshaft
c) Noe of cylinder
d) All of these

Which component convert up & down motion in to rotary motion of piston is called
a) Camshaft
b) Crankshaft
c) Connecting rod
d) Piston rings

When air transmit to engine by turbo charger, what will happen?
a) Transmit exhaust gases
b) Transmit increased air pressure
c) Make Vacuum
d) Less air pressure

The impeller type exhauster has
a) One spindle
b) Two spindle
c) Three spindle
d) No spindle

The pressure of pump in common rail diesel injection system is
a) 10 to 10000 pound / square inch
b) 200 to 300 pound / squarc inch
c) 400 to 800 pound / square inch
d) 700 to  pound / square inch

Which factor contribute to high fuel consumption?
a) Defect in Solenoid switch
b) Discharged battery
c) Clogged air cleaner-
d) Weak pressure relief valve

Lubrication oil consumption is high on a vehicle. Identify the cause
a) Breath filler removed
b) Battery is weak
c) Worn out piston rings
d) Alternator not charging

The ignition quality of diesel oil is expressed by-
a) Calorific value
b) Octane number
c) Cetane number
d) None of these

The thermal efficiency of diesel engine is about-
a) 15%

Which are following component used for oil pump run?
a. Crankshaft
b. Dammer pulley
c. Piston pin
d. Cam shaft

In engine specification it is given that cubic capacity is  engine's
a) 'Lubricating oil capacity is 1.6 lit.
b) One cylinder total volume is 1.6 lit.
c) All cylinders sweep volume 1.6 lit.
d) Cooling water circulation per minute is 1.6 lit.

Cylinder head accommodates
a) Valves and injectors
b) Crankshaft
c) Cylinders liners
d) Connecting Rods

Tachometer in a vehicle measures-
a) Speed  
b) Distance
c) Engine rpm
d) Fuel consumption



1.6 lit. it means the

The part which must be fitted in the piston to assure a good seal with cylinder wall is
a) Piston pins
b) Piston rings
c) Connecting rod
d) Gaskets




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July17 MECHANIC (DIESEL) THEORY SEMESTER-II

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