Compression ratio in case of SI engine in the range of
Right Answer is:
6 – 10
The compression ratio for an internal combustion engine is defined in the same way as for an external combustion engine, that is, maximum cylinder volume divided by minimum cylinder volume.
The higher the compression ratio, the higher is the effective efficiency in the range of particular interest to spark-ignition engines. In practice, the compression ratio is limited by the knock characteristics of the fuel.
The SI engines have lower compression ratios usually between 8 to 10 as compared to the Diesel engine which has a compression ratio of 16 to 22.