Internal Combustion Engines
JKSSB Junior Engineer (Mechanical) · Metrology and Automobile Engineering · 8 practice questions with answers and explanations: 0 Easy, 8 Medium, 0 Hard.
Sample questions
Sample Medium question 1
The knocking in an SI engine is caused by:
- late ignition
- auto-ignition of the end gas before the flame arrives
- a weak spark
- excess air
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Answer: B. A higher octane number resists it.
Sample Medium question 2
The knock tendency of a diesel fuel is measured by its:
- octane number
- calorific value
- cetane number
- viscosity index
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Answer: C. A higher cetane number means a shorter ignition delay.
Sample Medium question 3
A diesel engine does not have a:
- piston
- fuel injector
- spark plug
- crankshaft
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Answer: C. The air is compressed so much that the fuel ignites on injection.