Topic: IC Engines
How does cetane number varies with octane number in fuels in IC engines?
- A. No relation
- B. Directly proportional
- C. Inversely proportional
- D. Both are equal
Answer: C. Inversely proportional
Explanation: Cetane number is a measure of the ignition quality of diesel fuel (promotes auto-ignition), while octane number is a measure of the resistance of gasoline to auto-ignition (knocking). They are inversely proportional to each other. A fuel with a high octane number will have a low cetane number, and vice versa.