For the same compression ratio_____________________?

Diesel cycle is more efficient’than Otto

Otto cycle is more efficient than the Diesel

Diesel cycle is more efficient’than Otto

both Otto and Diesel cycles are, equally efficient

compression ratio has nothing to do with efficiency

which is more efficient would depend on engine capacity

For same power and same speed, the flywheel of a four stroke engine as compared to two-stroke I.C. engine will be________________?

dependent on other engine parameters

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

lean/rich mixture depending upon capacity of engine

Flash point of fuel oil is __________________?

temperature at which it solidifies or congeals

minimum temperature to which1 oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in cont

temperature at which it solidifies or congeals

temperature at which it catches fire without external aid

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

Exhaust pipes of engines are covered with insulating marterial in order to_________________?

reduce heat transfer to the engine room

Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the following______________?_x005F_x000D_Which of the following is false statement?

formation of hard coating on piston skirts

oil sludge in the engine crank case

Ethyl fluid is used_______________________?

to increase the cetane rating of the fuel

to increase the octane rating of the fuel

to increase the cetane rating of the fuel

as a superior type of fluid compared to others

to improve lubricating quality of fuel

Engine pistons ‘are usually made of aluminium alloy because it_________________?

does not react with fuel and lub oil

Diesel fuel, compared to petrol is_________________?

just about the same difficult to ignite

Diesel engines as compared to petrol engines require ______________________?

flywheel whose size may be less or more depending on several other fac-tors

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

there could not be any such criterion

true at both part and full load

there could not be any such criterion

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__________________?

can not work as it is impossible

Detonation is caused by the following unstable compounds______________________?

peroxides, aldehydes, oxides and sul-phides

peroxides, aldehydes and ketones

peroxides, aldehydes, oxides and sul-phides

Crankcase explosion in I.C. engines usuall occurs as ___________________?

first a big explosion followed by a mil explosion

first a mild explosion followed by a bi explosion

first a big explosion followed by a mil explosion

both mild and big explosions occi simultaneously

Compression ratio of LC. engines is ___________________?

volume displaced by piston per stroke and clearance volume in cylinder

the ratio of volumes of air in cylinder before compression stroke and after compression stroke

volume displaced by piston per stroke and clearance volume in cylinder

ratio of pressure after compression and before compression

Compression loss in I.C engines occurs due to_________________?

increase in clearance volume caused b bearing-bushing wear

Cetane___________________?

determines the efficiency of an I.C. engine

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

mixture of cetane and alphamethyl napthalene

mixture of aldehydes and ketones

mixture of cetane with tetra-ethyl lead

Carburretion is done to________________?

break up and mix the petrol with air

Auto-ignition temperature is____________________?

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

minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in conta

temperature at which it solidifies or congeals

that at which it catches fire without external aid

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

indicated by 50% distillation temperature

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________________?

Chemically correct fuel air ratio

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

Decreases upto a limit and then increases

According to Recardo’s theory, detonation occurs due to______________________?

improper mixing of air and fuel

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

improper mixing of air and fuel

self ignition temperature has nothing to do with detonation

A two stroke crank compressed engine has following ports in the cylinder_______________?

suction port, exhaust port and transfer port

A stoichiometric air-fuel ratio is______________________?

the ratio used at full rated parameters

A fuel will detonate less if it has___________________?

lower self ignition temperature

higher self ignition temperature

lower self ignition temperature

proper self ignition temperature

self ingition temperature has nothing to do with detonation

197 + Mcqs in IC Engines Page 4 McqOptions

151.	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
Answer» E. about 5 times

152.	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
Answer» C. centrifugal pump

153.	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
Answer» B. Diesel cycle is more efficient’than Otto

154.	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
Answer» C. same size

155.	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
Answer» C. 15 : 1

156.	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
Answer» D. any type of mixture

157.	For low load operation, more suitable (economical) engine is_______________?
A.	S.I. engine
B.	C.I. engine
C.	both are equally good
D.	multicylinder engine
E.	two stroke engine
Answer» C. both are equally good

158.	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 cont
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
Answer» B. temperature at which it solidifies or congeals

159.	Exhaust pipes of engines are covered with insulating marterial in order to_________________?
A.	keep the exhaust pipes warm
B.	reduce formation of condenstae
C.	reduce heat transfer to the engine room
D.	increase engine efficiency
E.	conserve heat
Answer» D. increase engine efficiency

160.	Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the following______________?_x005F_x000D_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
Answer» E. forms corrosive acids

161.	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
Answer» B. to increase the cetane rating of the fuel

168.	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
Answer» D. reducing the r.p.m.

177.	Carbon residue in diesel oil should not be more than___________________?
A.	1%
B.	0.5%
C.	0.1%
D.	0.01%
E.	0.001%
Answer» F.

181.	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
Answer» C. rate of rise of temperature

183.	An engine has a normal speed of 960 r.p.m. and no load speed of 1000 r.p.m. The speed droop of governor will be about___________________?
A.	2%
B.	4%
C.	8%
D.	±4%
E.	1%.
Answer» C. 8%

162.	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
Answer» B. wears less

163.	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
Answer» D. highly ignitable

164.	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
Answer» B. smaller flywheel

165.	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
Answer» E. there could not be any such criterion

166.	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
Answer» D. flywheel size is proper

167.	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
Answer» B. peroxides, aldehydes, oxides and sul-phides

169.	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
Answer» D. volumetric efficiency

170.	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
Answer» B. first a big explosion followed by a mil explosion

171.	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
Answer» B. volume displaced by piston per stroke and clearance volume in cylinder

172.	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
Answer» F.

Explore topic-wise MCQs in Mechanical Engineering Questions.

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

For the same power developed in I.C. engines, the cheaper system is_____________?

For the same compression ratio_____________________?

For same power and same speed, the flywheel of a four stroke engine as compared to two-stroke I.C. engine will be________________?

For maximum power generation, the air fuel ratio for a petrol engine for vehicles, is of the order of _________________?

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

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

Flash point of fuel oil is __________________?

Exhaust pipes of engines are covered with insulating marterial in order to_________________?

Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the following______________?_x005F_x000D_Which of the following is false statement?

Ethyl fluid is used_______________________?

Engine pistons ‘are usually made of aluminium alloy because it_________________?

Diesel fuel, compared to petrol is_________________?

Diesel engines as compared to petrol engines require ______________________?

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

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__________________?

Detonation is caused by the following unstable compounds______________________?

Detonation can be controlled by_____________________?

Deposition of carbon in petrol engine cylinder would result in increase of__________________?

Crankcase explosion in I.C. engines usuall occurs as ___________________?

Compression ratio of LC. engines is ___________________?

Compression loss in I.C engines occurs due to_________________?

Combustion in compression ignition engines is____________________?

Cetane___________________?

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

Carburretion is done to________________?

Carbon residue in diesel oil should not be more than___________________?

Auto-ignition temperature is____________________?

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________________?

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

As a result of detonation in an I.C. engine, following parameter attains very high value _____________________?

An engine indicator is used to determine the following___________________?

An engine has a normal speed of 960 r.p.m. and no load speed of 1000 r.p.m. The speed droop of governor will be about___________________?

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

All heat engines utilize_____________________?

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

Air fuel ratio for idling speed of a petrol engine is approximately_________________?

Air fuel ratio at which a petrol engine can not work is_________________?

According to Recardo’s theory, detonation occurs due to______________________?

A two stroke engine is usually identified by__________________?

A two stroke crank compressed engine has following ports in the cylinder_______________?

A stoichiometric air-fuel ratio is______________________?

A hmh flame speed is obtained in diesel engine when air fuel ratio is_______________?

A heat engine utilises the_________________?

A fuel will detonate less if it has___________________?

A diesel engine as compared to petrol engine (both running ar rated load) is ____________________?

A diesel engine has_________________?

173.	Combustion in compression ignition engines is____________________?
A.	homogeneous
B.	heterogeneous
C.	both A. and B.
D.	laminar
E.	turbulent
Answer» C. both A. and B.

174.	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
Answer» E. determines the efficiency of an I.C. engine

175.	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
Answer» C. ethylene dibromide

176.	Carburretion 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
Answer» D. heat up the charge to cylinder

178.	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 conta
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
Answer» D. indicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off

179.	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
Answer» C. Rich mixture

180.	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
Answer» B. Increases

182.	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
Answer» E. BHP

184.	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
Answer» C. Two

185.	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
Answer» B. high heat value of oil