I.C. Engines Mcqs
This set of Mechanical engineering Multiple Choice Questions & Answers (MCQs) focuses on study of “ Integrated Circuit Engines ”. These questions are chosen from a collection of most authoritative and best reference books on Mechanical engineering. Our aim is to prepare an individual for competitive exams like NTS, GAT, ECAT, University and College entrance exams, Jobs and interviews. One should practice our MCQS to assimilate I.C. Engines comprehensively.
32. 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__________________?
It is properly designed
Best quality fuel is used
Can not work as it is impossible
Flywheel size is proper
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33. The knock in diesel engine occurs due to____________________?
Instantaneous and rapid burning of the first part of the charge
Instantaneous atuo iginition of last part of charge
Delayed burning of the first part of the charge
Reduction of delay period
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34. The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft___________________?
1/2
1
2
4
35. Scavenging air in diesel engine means___________________?
Air used for combustion sent under pres-sure
Forced air for cooling cylinder
Burnt air containing products of combustion
Air used for forcing burnt gases out of engine’s cylinder during the exhaust period
Answer & Solution
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36. Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged ?
Yes
No
To some extent
Unpredictable
37. The air standard efficiency of an Otto cycle compared to diesel cycle for the given compression ratio is__________________?
Same
Less
More
More or less depending on power rating
38. In a diesel engine, the fuel is ignited by___________________?
Spark
Injected fuel
Heat resulting from compressing air that is supplied for combustion
Ignition
Answer & Solution
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39. The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called__________________?
Net efficiency
Efficiency ratio
Relative efficiency
Overall efficiency
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40. If the intake air temperature of I.C. engine increases, its efficiency will_________________?
Increase
Decrease
Remain same
Unpredictable
Answer & Solution
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41. An engine indicator is used to determine the following___________________?
Speed
Temperature
Volume of cylinder
M.e.p. and I.H.P.
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42. In a typical medium speed 4-stroke cycle diesel engine the inlet valve_____________________?
Opens at 20° before top dead center and closes at 35° after the bottom dead center
Opens at top dead center and closes at bottom dead center
Opens at 10° after top dead center and closes 20° before the bottom dead center
May open or close anywhere
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43. The pressure at the end of compression in the case of diesel engine is of the order of___________________?
6 kg/cm
12kg/cmz
20 kg/cmz
27.5 kg/cmz
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44. If the compression ratio of an engine working on Otto cycle is increased from 5 to 7, the %age increase in efficiency will be________________?
2%
4%
8%
14%
45. The thermal efficiecny of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will___________________?
Increase
Decrease
Be independent
May increase or decrease depending on other factors
Answer & Solution
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