Combustion Analysis of Low-Speed Marine Engine Fueled with Biofuel

To study the applicability of biodiesel in marine engines, this research investigated the performance, combustion characteristics, and emission characteristics of biodiesel (B100), diesel, and a 50% volume blend of the two fuels (B50) in a marine engine. This study was conducted on a 4-cylinder, 520 mm-bore, two-stroke, low-speed marine engine with a common rail fuel and exhaust gas charge system. The three fuels were tested at different loads from 25%–100% with a step size of 25%. Results showed that the fuel consumption of pure biodiesel increased by about 13.5% and 3.8% relative to that of diesel at 25% and 100% loads, respectively, and by about 6% at 50% and 75% loads. In-cylinder combustion pressure was slightly reduced when the engine ran on biofuel, and black carbon emissions from biodiesel were reduced by an average of 54.7%. Compared with those from diesel, the carbon CO and total hydrocarbon emissions from B100 were reduced by 11.3% and 39%, respectively. Nitroxide emissions were elevated for B100 and B50 under all loading conditions. The properties of B50 blended diesel lie between those of B100 and diesel. In terms of combustion characteristics and emissions, biodiesel can be used without changing the engine parameters and can effectively reduce pollution, such as black carbon and carbon monoxide.