The Influence of Pilot and Split-Main Injection Parameters on Diesel Emissions and Fuel Consumption

The paper outlines experimental investigations of fuel injection strategies which are possible using high pressure common rail fuel injection systems. Strategies using a split main with a pilot injection have been explored. The strategy variables were the ratio of the first to second part of the main, the separation between these and the timing of the start of main injection. Exhaust gas recirculation rate was a fourth variable. Pilot injection quantity and timing, and rail pressure were held constant. The influence on emissions and specific fuel consumption is described and the method of optimising settings is outlined. The manipulation of fuel injection settings to best meet optimisation targets for emissions and specific fuel consumption is described. The benefits compared to results for optimised single main injection are described, as are issues of strategy robustness.