Experimental Investigation of rail pressure and injection timing effects on performance and emission characteristics of a common rail heavy duty diesel engine

Common rail fuel systems which have a near square shape fuel injection rate provide accurate electronic control over the fuel injection time and quantity. The higher injection pressure which is intrinsic to common rail technology provides better fuel atomization and thus more homogeneity. In order to get utmost from this fueling system, optimized rail pressure and injection timing should be utilized. In this study a common rail heavy duty diesel engine designed and manufactured in Iran Heavy Duty Diesel Engine Mfg. Co. (DESA) was investigated. The main objective of the experiments was to provide an optimized look-up table for ECU. In order to optimize the rail pressure and delivery begin point, RSM methodology was used. Utilizing RSM, the quadratic response surface was calculated. Then, the optimization was done using multi objective genetic algorithm. The objectives were minimizing BSFC, BSNOx, BSSoot and peak pressure over end-of-compression pressure ratio with their weighting factors of 0.3, 0.35, 0.25 and 0.1, respectively. The experiments resulted in an optimized look-up table. This look-up table is an optimized one in terms of BSFC and emissions.

Keywords:

Common rail , emission , ECU map , timing