Numerical simulation of improving diesel engine emission pollutants through fuel injection strategy

Optimizing multiple fuel injection strategies has a significance for enhancing diesel engine combustion performance, reducing the generation of emission pollutants, and improving traffic environmental pollution. Using CONVERGE simulate the effects of different fuel injection strategies on diesel engine combustion processes and emission pollutant distribution, the results shows that: at maximum compression ratio 16.5, 2200 rpm and injection pressure of 160MPa, fuel injection quantity of 47.6mg in a cycle, lean mixtures with equivalence ratio of 0.6~1.0 are prone to spontaneous combustion, causing an increase in the temperature of the mixture and an expansion of the concentration range of spontaneous combustion mixture, which promotes the combustion of rich mixtures with equivalence ratio of 1.0~1.3. When the main injection advance angle is 12° CA BTDC, by changing the self-ignition time of the lean and rich mixture, the combustion heat is more concentrated near the compression top dead center, resulting in the maximum average indicated pressure and a increase of 3.8%, and promotes a reduction in emission pollutants more than 6.2%. When the proportion of pre-injected fuel increases from 5% to 10%, the heat release of the lean mixture during the pre-mixed combustion stage gradually increases, resulting in a maximum pressure increase rate of 22.9%, and promotes a reduction in emission pollutants more than 7.8%. The fuel injection strategies reduce the generation of diesel engine emission pollutants can provide guidance for environmental pollution control in the transportation sector.