What is the typical compression ratio for CNG engines?

The typical compression ratio for Compressed Natural Gas (CNG) engines typically falls within the range of 12:1 to 15:1. This higher compression ratio is advantageous for CNG engines because it allows for better thermal efficiency and increased power output compared to gasoline engines. CNG has a higher octane rating, which enables it to withstand the higher compression without experiencing knocking.

Engines operating within this compression ratio range are designed to optimize the combustion process, leading to more efficient fuel usage and lower emissions. Therefore, selecting a compression ratio between 12:1 and 15:1 is conducive to enhancing the performance characteristics of CNG engines, aligning with the operational benefits associated with using compressed natural gas as a fuel source.

The ranges listed in the other options do not accurately reflect the typical compression ratios found in CNG engines, as they either fall below or above the optimal range necessary for efficiency and performance.