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.Management Sciences
Category: I.C. Engines
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
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
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
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
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°
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
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.
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
Pick up false statement?
A. For petrol and large gas engines, quantity governingds 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
The knocking in diesel engines for given fuel, will be__________________?
A. enhanced by increasing compression ratio
B. enhanced by decreasing compression ratio
C. unaflected by compression ratio
D. first enhanced by increasig compression ratio upto a limit beyond which it will be suppressed
E. dependent on other factors
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