Study on influence of fuel injection parameters on combustion and emission characteristics of biodiesel engine

Based on the dual solenoid valve control strategy of ultra-high pressure fuel injection device to achieve ultra-high pressure and variable law injection, a simulation model of the combustion process of biodiesel engine was established, and the model was modified and verified by experimental data. Then, the influence of the combustion and emission performance of biodiesel engine on the injection characteristics (injection pressure and injection law) was studied. The results indicate that when a certain control strategy is adopted to adjust the opening and closing timing of the solenoid valves in the fuel injector and electronic supercharger, ultra-high pressure and variable injection law can be achieved. Under the saddle-shaped fuel injection law, a higher injection pressure is beneficial for the mixing of fuel and air in the cylinder, which can improve fuel atomization and reducing soot emissions. When the fuel injection law changes from rectangular shape to sloping shape, and then to saddle-shaped, the maximum cylinder pressure and cylinder temperature of the biodiesel engine gradually decrease, resulting in better fuel air mixing and more complete combustion, additionally the NO x generation decreases by 42.8% while the soot generation only increases by 1.8%.