Influence of fuel injection timing strategies on performance, combustion, emissions and particulate matter characteristics fueled with rapeseed methyl ester in modern diesel engine

The combination between different conditions of fuel injection timings and biodiesel is a major challenge for the communities of vehicle research in terms of efficiency and emissions. The difficulties to achieving the emissions regulations in the recent years are linked to undesirable health effects and environmental impact. The effects of different engine conditions (injection timings and loads) on combustion, emissions, and particulate matter (PM) characteristics for diesel and biodiesel (B100) in diesel engine were experimentally investigated in this study. The combustion characteristics of cylinder pressure and rate of heat release (ROHR) were slightly higher during the combustion of B100 and advanced injection timing than during the combustion of diesel. Results have shown that THC and CO decreased from B100 combustion by 21% and 31% under 5 brake mean effective pressure (BMEP), respectively, and 32% and 46% under 2.5 BMEP of engine load compared to the diesel. Furthermore, advanced injection timing decreased CO and THC compared with retarded injection timing for B100 and diesel under both conditions of engine loads. However, nitrogen oxide (NOX) decreased (by 24%) with retarded injection timing and increased (by 7%) with advanced injection timing. Smoke number and particle number concentration decreased under conditions of advanced injection timing compared with retarded injection timings, especially during B100 combustion. In terms of particulate size, d(po) decreased by 26.6 nm during B100 combustion and by 32.7 nm during diesel combustion under different conditions of injection timings and engine loads. The oxygen-bond in B100 contributed to important benefits in terms of NOX and PM without substantial influence on combustion characteristics and efficiencies.

Automated summary

The study found that there are differences in combustion characteristics and emissions between biodiesel and diesel under different engine conditions. Biodiesel showed better emission performance in some aspects compared to diesel, and advanced injection timing has a positive effect on reducing CO and THC but increases NOX emissions.