Characteristics of particulate emissions of compression ignition engine fueled with biodiesel derived from soybean

An experimental investigation was performed on the effect of engine speed and EGR (exhaust gas recirculation) on the particle size distribution and exhaust gas emissions in a compression ignition engine fueled with biodiesel derived from soybean. The results obtained by biodiesel fuel were compared to those obtained by petroleum diesel fuel with sulfur contents of 16.3 ppm. The scanning mobility particle sizer (SMPS) was used for size distribution analysis and it measured mobility equivalent particle diameter in the range of 10.4 to 392.4 nm. In addition to the size distribution of the particles, exhaust emissions such as oxides of nitrogen (NOx), hydrocarbon (HC), and carbon monoxide (CO) emissions and combustion characteristics under different engine operating parameters were investigated. The engine operating parameters in terms of engine speed, EGR, injection pressure, and intake pressure were varied to investigate the individual impact of the operating parameters. As the engine speed was increased for the both fuels, the larger size particles which dominantly contributes particle mass was increased, however total numbers of particle were reduced. Comparing to petroleum diesel fuel, the combustion of biodiesel fuel in the engine reduced particle concentration of relatively larger size where most of the particle mass is found. Moreover, dramatically lower hydrocarbon and carbon monoxide emissions were found at the biodiesel fueled engine. However, the NO, emission of biodiesel fueled diesel engine shows slightly higher concentration compared to diesel fuel at the same injection timing.