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.Management Sciences
Category: I.C. Engines
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 thermal efficiecny 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
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
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
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 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-
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
According to Recardo’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
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
Ignition quailty of petrol is expressed by___________________?
A. octane number
B. cetane number
C. calorific value
D. self ignition temperature
E. distillation temperature
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