MCQOPTIONS
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MCQOPTIONS
This section includes 8 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Increasing the compression ratio in SI engines _________ the detonation tendency. |
| A. | increases |
| B. | does not affect |
| C. | decreases |
| D. | first increases and then decreases |
| Answer» B. does not affect | |
| 2. |
Consider the following statements with regard to IC engines:1. For best fuel economy of spark ignition engines, the fuel-air mixture should be lean2. With supercharging, the specific consumption in compression ignition engines increases3. With increase of load, knocking tendency in compression ignition engines increasesWhich of the above statements are correct? |
| A. | 1 and 2 only |
| B. | 2 and 3 only |
| C. | 1 and 3 only |
| D. | 1, 2 and 3 |
| Answer» D. 1, 2 and 3 | |
| 3. |
______ in the fuel is oxidised during knocking. |
| A. | Water |
| B. | Phosphorous |
| C. | Coal |
| D. | Hydrocarbon |
| Answer» E. | |
| 4. |
By adding tetraethyl lead to iso-octane |
| A. | Exhaust smoke can be reduced |
| B. | Knocking can be completely suppressed |
| C. | Octane number above 100 can be obtained |
| D. | Specific fuel consumption can be reduced |
| Answer» C. Octane number above 100 can be obtained | |
| 5. |
In spark ignition engines knocking can be reduced by: |
| A. | Increasing the compression ratio |
| B. | Increasing the cooling water temperature |
| C. | Retarding the spark advance |
| D. | Increasing the inlet air temperature |
| Answer» D. Increasing the inlet air temperature | |
| 6. |
Detonation in the S.I. engine becomes severe during |
| A. | Low load and high speed |
| B. | High load and high speed |
| C. | Low load and low speed |
| D. | High load and low speed |
| Answer» E. | |
| 7. |
Knock in a diesel engine occurs due to: |
| A. | instantaneous auto-ignition of last part of the charge |
| B. | reduction of the delay period |
| C. | delayed burning of the first part of the charge |
| D. | instantaneous burning of the first part of the charge |
| Answer» D. instantaneous burning of the first part of the charge | |
| 8. |
For a given compression ratio, to reduce the tendency to knock in an S I engine: |
| A. | Spark timing may be retarded |
| B. | The spark plug may be located farthest from the exhaust valve |
| C. | A quiescent combustion chamber with slower flame propagation rate may be used |
| D. | Organic nitrites may be used in the fuel |
| Answer» B. The spark plug may be located farthest from the exhaust valve | |