Comparative evaluation of performance, emission, lubricant and deposit characteristics of spark ignition engine fueled with CNG and 18% hydrogen-CNG

Gaseous fuels such as CNG and hydrogen are promising alternative fuels which receive more attention all over the world. This paper investigates the effect of compressed natural gas (CNG) and 18% hydrogen blended compressed natural gas (HCNG) on a retrofitted gasoline genset engine’s performance, emissions, deposits and lubricants under long duration testing. During the 60 h test, lower BSFC, CO and HC are observed for HCNG with the penalty of NOx values. The deposits of iron on spark plug and cylinder liner are higher for HCNG compared to CNG. As kinematic viscosity and TBN values of lubricant decreased significantly with HCNG, it has resulted in higher concentration of wear metals (iron and copper) in the used oil.

► Endurance test 60 h duration using CNG and 18% hydrogen blended CNG.
► Gas engine oil performed well when tested with CNG.
► For HCNG the lubricant’s kinematic viscosity dropped by 14% and TBN decreased by 30% resulting in increased value of wear metal.
► Deposits of iron were found on the spark plug and cylinder liner.