Chapter: Fuels and its Supply System SI and CI engine
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 above
Answer» B. it can mix easily with air
2.

Paraffins are in general represented by

A. CnHn
B. CnH2n
C. CnH2n+2
D. CnH2n-6
Answer» C. CnH2n+2
3.

Paraffins have molecular structure of

A. chain saturated
B. chain unsaturated
C. ring saturated
D. ring unsaturated
Answer» A. chain saturated
4.

Olefins are represented by the formula

A. CnH2n
B. CnH2n+2
C. CnH2n-4
D. CnH2n-6
Answer» A. CnH2n
5.

Hydrocarbons are decomposed into smaller hydrocarbons by

A. reforming
B. refining
C. cracking
D. polymerization
Answer» C. cracking
6.

The molecular structure of the straight-run gasoline is changed by

A. cracking
B. reforming
C. reining
D. boiling
Answer» B. reforming
7.

For SI engines fuels most preferred are

A. aromatics
B. parafins
C. olefins
D. napthenes
Answer» A. aromatics
8.

For CI engine fuels most preferred are

A. napthenes
B. paraffins
C. olefins
D. aromatics
Answer» B. paraffins
9.

Octane number of iso-octane is

A. 0
B. 30
C. 60
D. 100
Answer» D. 100
10.

Ignition quality of diesel fuel is indicated by its

A. octane number
B. cetane number
C. fash point
D. fire point
Answer» B. cetane number
11.

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
Answer» 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
12.

Gasohol is a mixture of

A. 90% ethanol + 10% gasoline
B. 10% ethanol +90% gasoline
C. 40% ethanol + 60% gasoline
D. 50% ethanol +50% gasoline
Answer» B. 10% ethanol +90% gasoline
13.

Stoichiometric air-fuel ratio of petrol is roughly

A. 50:1
B. 25:1
C. 15:1
D. 1:1
Answer» C. 15:1
14.

Venturi in the carburetor results in

A. decrease of air velocity
B. increase of air velocity
C. decrease of fuel flow
D. increase of manifold vacuum
Answer» B. increase of air velocity
15.

The choke is closed when the engine is

A. accelerating
B. hot
C. cold
D. idling
Answer» C. cold
16.

Lean air mixture is required during

A. idling
B. starting
C. accelerating
D. cruising
Answer» D. cruising
17.

The limits of air-fuel for SI engine are

A. 8/1 to 18/1
B. 8/1 to 50/1
C. 25/1 to 50/1
D. 50/1 to 100/1
Answer» A. 8/1 to 18/1
18.

For maximum thermal efficiency, the fuel-air mixture in SI engines should be

A. lean
B. rich
C. stoichiometric
D. may be rich or lean
Answer» A. lean
19.

During starting petrol engines require

A. stoichiometric mixture
B. lean mixture
C. rich mixture
D. any air-fuel ratio is alright
Answer» C. rich mixture
20.

Economizer is used to provide enriched mixture during

A. Starling
B. idling
C. cruising
D. full throttle operation
Answer» D. full throttle operation
21.

When the throttle is suddenly opened, the mixture of the simple carburetor tends to become

A. rich
B. lean
C. stoichiometric
D. not affected
Answer» B. lean
22.

Precise petrol injection system is

A. direct injection
B. sequential injection
C. throttle body injection
D. port injection
Answer» C. throttle body injection
23.

The choke in an automobile meant for supplying

A. lean mixture
B. rich mixture
C. stoichiometric mixture
D. weak mixture
Answer» B. rich mixture
24.

Modern carburetors provide the correct quality of air-fuel mixture during

A. starting
B. idling
C. cruising
D. all conditions
Answer» D. all conditions
25.

A simple carburetor supplies rich mixture during

A. starting
B. idling
C. cruising
D. accelerating
Answer» D. accelerating
26.

Fuel injector is used for

A. gas engines
B. CI engines
C. SI engines
D. none of the above
Answer» B. CI engines
27.

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 above
Answer» D. all of the above
28.

Commonly used injection system in automobiles is

A. air injection
B. solid injection
C. combination of (a) and (b)
D. none of the above
Answer» B. solid injection
29.

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. 200-250 bar
30.

Fuel filters do not use generally

A. oil
B. paper
C. cloth
D. felt
Answer» B. paper
31.

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. at the end of compression stroke
32.

Injection system in which the pump and the injector nozzle is combined in one housing is known as

A. common rail system
B. distributor system
C. unit injector system
D. individual pump and nozzle system
Answer» C. unit injector system
33.

Main advantage of pintaux nozzle is

A. better cold starting performance
B. ability to distribute the fuel
C. good penetration
D. good atomization
Answer» A. better cold starting performance
34.

the most accurate gasoline injection system is

A. direct injection
B. port injection
C. throttle body injection
D. manifold injection
Answer» B. port injection
35.

Advantage of fuel injection in SI engine is

A. low initial cost
B. low maintenance requirements
C. increased volumetric efficiency
D. none of the above
Answer» C. increased volumetric efficiency
36.

‘MPFI’ stands for

A. Multi point fuel injection
B. Multi port fuel injection
C. Manifold point fuel injection
D. Manifold port fuel injection
Answer» A. Multi point fuel injection
37.

In carburetor, Choke is incorporated

A. Before the venturi
B. After the venturi
C. In the venturi
D. Any of the above
Answer» A. Before the venturi
38.

The following factors affect the process of carburetion

A. Engine speed
B. The temperature of incoming air
C. The volatility of fuel
D. All of the above
Answer» D. All of the above
39.

In MPFI _____ is used to spray fuel into engine.

A. Engine vacuum
B. Suction pressure of engine
C. Electric pump
D. None of the above
Answer» B. Suction pressure of engine
40.

L-MPFI system uses

A. port injection
B. direct injection
C. manifold injection
D. throttle body injection
Answer» A. port injection
41.

D-MPFI system uses

A. port injection
B. manifold injection
C. direct injection
D. throttle body injection
Answer» B. manifold injection
42.

Common rail injection system uses injection pressures of the order

A. 100-200 bar
B. 200-400 bar
C. 400-600 bar
D. 1500 bar
Answer» D. 1500 bar
43.

Continuous injection system usually has

A. plunger pump
B. rotary pump
C. gear pump
D. vane pump
Answer» B. rotary pump
44.

The cold start injector

A. maintain stoichiometric air-fuel ratio
B. provides lean air-fuel ratio
C. gives rich air-fuel ratio
D. is not used for any of the above functions
Answer» C. gives rich air-fuel ratio
45.

ECU is an electronic injection system used for

A. calculating the appropriate injection timing
B. meeting only certain operating conditions
C. closing the injection valve only
D. none of the above
Answer» A. calculating the appropriate injection timing
46.

With EFI (ELECTRONIC FUEL INJECTION) of diesel engines

A. sharp start and stop is not possible
B. very high injection pressure can be obtained
C. sudden cylinder cut-off is impossible
D. diagnostic properties are poor
Answer» B. very high injection pressure can be obtained
47.

EFI system can achieve

A. proper injection timing
B. proper injection quantity
C. proper injection pressure
D. all of the above
Answer» D. all of the above
48.

The first vehicle in India equipped with MPFI system in Indian automobile industry

A. Tata Indica
B. Daewoo Matiz
C. Maruti Alto
D. Chevrolet spark
Answer» B. Daewoo Matiz
49.

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
Answer» D. 90-130 kg/cm2
50.

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
Answer» B. 0.2 kg
51.

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
Answer» C. 0.25 kg
52.

The air-fuel ratio of the petrol engine is controlled by

A. fuel pump
B. governor
C. injector
D. carburettor
Answer» D. carburettor
53.

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
Answer» B. temperature at which it solidifies or congeals
54.

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
Answer» B. 1 kg/hr
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