To reduce the possibility of knock in the C.I. engines, the first elements of fuel and air should have_______________?

Related Mcqs:

1. The specific fuel consumption for a petrol engine first decreases with increase in fuel air ratio and then increases with further increase in fuel air ratio. The minimum value occurs in the range of__________________?

   A. lean mixture B. chemically correct mixture C. rich mixture D. unpredictable E. none of the above...

2. In order to prevent knock in the S.I. engines, the charge away from the spark plug should have___________________?

   A. low temperature B. low density C. long ignition delay D. rich mixture E. all of the above...

3. 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...

4. The m.e.p. of a petrol engine first increases as the fuel air ratio is increased and then decreases on further increase in fuel air ratio. The M.E.P is maximum in the zone of________________?

   A. lean mixture B. chemically correct mixture C. rich mixture D. unpredictable E. none of the above...

5. In petrol engines, the maximum power is developed corresponding to relative fuel air ratio of________________?

   A. 0.85 B. 1 C. 1.1 to 1.3 D. 1.2 to 1.5...

6. Diesel engines as compared to petrol engines require ______________________?

   A. bigger flywheel B. smaller flywheel C. same size flywheel D. no flywheel E. flywheel whose size may be less or more depending on several other fac-tors...

7. The air-fuel ratio in petrol engines-is controlled by__________________?

   A. controlling valve opening/closing B. governing C. injection D. carburettion E. scavenging and supercharging...

8. Which is correct statement about reaction time for autoignition of fuel and the fuel air ratio__________________?

   A. lean mixture has high reaction time B. rich mixture has high reaction time C. chemically correct mixture has mini-mum reaction time D. all of the above E. non of the above...

9. Diesel engines have low specific fuel consumption compared to petrol engine. This statement is____________________?

   A. not true B. true at full load C. true at part load D. true at both part and full load E. there could not be any such criterion...

10. 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...