Abstract
This current experimental investigation attempts to explore the engine performance, combustion behaviour, and exhaust emission of a 3.5 kW capacity diesel engine utilizing synthetic-biogas (SBG), synthetic producer gas (SPG), and SBG-SPG mixture under dual fuel (DF) mode. SBG is prepared by mixing methane (CH4) and carbon dioxide (CO2) at 60:30 ratio. Similarly, hydrogen (H2) and carbon monoxide (CO) are also mixed at a 50:50 ratio for the preparation of SPG. Again, H2 and CO at a 50:50 ratio is mixed with a 60:30 ratio of CH4 and CO2 to simulate the SBG-SPG mixture. Engine experiments were executed at standard engine conditions of injection timing (IT) of 23° BTDC and compression ratio (CR) of 17.5 with five different engine loading conditions viz. 20%, 40%, 60%, 80%, and 100%. Maximum brake thermal efficiency (BTE) and pilot fuel replacement (PFR) were obtained at full engine loading condition. At this operating condition, SBG, syngas, and SBG-SPG mixture showed a BTE of 18.2%, 15.92%, and 18.89% respectively. Similarly, PFR of 84%, 78.74%, and 82.92% was found in case of SBG, SPG, and SBG-SPG mixture respectively. The combustion data indicated a decrement in ignition delay (ID) and increment in cylinder pressure with higher engine load. At 100% engine load, minimum ID of 20, 21 and 22° crank angle (CA) was obtained for SBG, SPG, and SBG-SPG mixture respectively. Again, highest peak cylinder pressure (PCP) was obtained for SBG-SPG mixture. It has also been observed that on an average, SPG resulted in higher emission including oxides of nitrogen (NOx), hydrocarbon (HC) and carbon monoxide (CO) compared to SBG. However, mixture of SBG-SPG resulted in 57.48, 0.09 and 5.6% reduction in NOx, HC and CO emissions respectively as compared to SPG.
