Question:-
Assertion (A) : Knocking in S.I. engines is due to auto-ignition of the end charge while knocking in C.I. engines is due to auto-ignition of the first charge.
Reason (R) : Spark ignition engines employ lower compression ratio than diesel engines and the fuel used has a calorific value lower than that of diesel oil.
Option (A)
Both A and R are true and R is the correct explanation of A
Option (B)
Both A and R are true but R is NOT the correct explanation of A
Option(C)
A is true but R is false
Option(D)
A is false but R is true
Correct Option:
(A)
Question Solution:
Diesel has higher calorific value and high specific gravity than gasoline fuel but they have low self ignition temperature and less volatility, less flash point in comparison to gasoline.
Knocking in SI due to ignition of end charge while detonation in CI engine due to autoignition of the first charge.
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