Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged ?

Related Mcqs:

1. Scavenging air is supplied to a two-stroke engine at a density greater than that of atmosphere. This means the engine is__________________?

   A. Supercharged
   B. Not supercharged
   C. Charged
   D. Supercharged provided its speed is low

2. The thermal efficiency of a petrol engine of two stroke with crank case scavenging as compared to four stroke petrol engine with same comperssion ratio will be_____________________?

   A. higher
   B. lower
   C. same
   D. depends on size of engine
   E. unpredictable.

3. 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

4. In the crankcase method of scavenging, the air pressure is produced by_________________?

   A. supercharger
   B. centrifugal pump
   C. natural aspirator
   D. movement of engine piston
   E. reciprocating pump

5. 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

6. The ratio of useful power; engine friction exhaust gas losses; cooling water, air and oil losses for a diesel engine is of the order of____________________?

   A. 5:25:30:50
   B. 25:35:5:35
   C. 25:5:10:60
   D. 40:30:15:15
   E. 25:5:35:35

7. The term scavenging is generally associated with______________________?

   A. 2-stroke cycle engines
   B. 4-stroke cycle engines
   C. aeroplane engines
   D. diesel engines
   E. high efficiency engines

8. Scavenging is usually done to increase__________________?

   A. thermal efficiency
   B. speed
   C. power output
   D. fuel consumption
   E. all of the above

9. In loop scavenging, the top of the piston is________________?

   A. flat
   B. contoured
   C. slanted
   D. depressed
   E. convex shaped

10. 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