Question

What is the compression ratio in SI engine?

(a) 6 – 10

(b) 3 – 5

(c) 1 – 2

(d) 11 – 15

I had been asked this question during an interview for a job.

Origin of the question is I.C Engine topic in section Internal Combustion Engine of Farm Machinery

Answer 1

Correct option is (a) 6 – 10

The explanation is: Gasoline, a highly volatile fuel is used in SI engines and upper limit is fixed by antiknock quality of fuel. Compression ratio in SI engine is 6 – 10.