Performance evaluation of a constant speed IC engine on CNG, methane enriched biogas and biogas

This paper presents the performance results of a 5.9 kW stationary diesel engine which was converted into spark ignition mode and run on compressed natural gas (CNG), methane enriched biogas (Bio-CNG) and biogas produced from biomethanation of jatropha and pongamia oil seed cakes. The performance of the engine with 12.65 compression ratio was evaluated at 30°, 35° and 40° ignition advance of TDC. The maximum brake power produced by the engine was found at ignition advance of 35° TDC for all the tested fuels. In comparison to diesel as original fuel, the power deteriorations of the engine was observed to be 31.8%, 35.6% and 46.3% on compressed natural gas, methane enriched biogas and raw biogas, respectively, due to its conversion from CI to SI mode. The methane enriched biogas showed almost similar engine performance as compared to compressed natural gas in terms of brake power output, specific gas consumption and thermal efficiency.

► Gaseous fuels CNG, methane enriched biogas and raw biogas was evaluated in spark ignition engine converted from diesel engine at 30°, 35° and 40° ignition advance of TDC.
► Best engine performance was found at 35° ignition advance of TDC.
► Power loss due to engine conversion was found as 31.8%, 35.6% and 46.3% for CNG, methane enriched biogas and raw biogas, respectively.
► Methane enriched biogas showed almost similar engine performance as compared to CNG in terms of brake power output, specific gas consumption and thermal efficiency.