Assessment of using Soybean Biodiesel Fuel on Performance and Exhaust Emission Characteristics of a Common-rail Diesel Engine (OM۳۵۵)

The impact of performance and exhaust emission features of a common-rail diesel engine OM۳۵۵ using a biodiesel/diesel mix (volume ratios of B۵, B۱۰, and B۱۵) was analyzed in this study. Between engine speeds of ۱۰۰۰ and ۱۵۰۰ RPM, there was an observed increase in power and torque, with enhancements of ۵% and ۰.۵%, respectively. Conversely, at elevated engine speeds, specifically from ۱۸۰۰ to ۲۲۰۰ RPM, both power and torque exhibited a reduction ranging from ۱ to ۴% in comparison to conventional diesel fuel. The brake-specific fuel consumption (BSFC) decreased by ۴ to ۱% at low and medium speeds, particularly between ۱۰۰۰ and ۱۵۰۰ RPM, due to the reduction in energy content from using soybean biodiesel. However, at high speeds in the range of ۱۸۰۰ to ۲۲۰۰ RPM, BSFC increased by ۱ to ۳.۵%. In addition, the results of the emissions test indicated that emissions from mixed fuels were significantly higher than those from regular fuel or diesel owing to the lack of any engine modifications. Based on the test results, despite the increase in pollutant emissions using mixed fuels, the emission levels of the aforementioned fuels were within the Euro ۵ standard limits. Considering that diesel engines operate optimally at middle speeds, which is their maximum torque range, and considering the engine performance features, the utilization of biodiesel blends B۵, B۱۰, and B۱۵ is acceptable for the engine performance. To reduce the adverse effects of biodiesel combustion, various methods, such as preheating the fuel, increasing the fuel rail pressure, decreasing the injection duration, using additives, and retuning electronic engine control (ECU) units based on the biodiesel characteristics, could be utilized as a viable replacement in diesel engines.