To investigate the fuel injection strategy for large low speed marine diesel engines

a micro-genetic algorithm coupled with 3D numerical simulation was applied to the optimization of start of injection timing(SOI)

pilot injection interval and pilot fuel fraction of two injectors. The effect of the pilot injection parameters and sequential injection of each injector on engine performance and emissions was further investigated based on the optimized case. Results show that for the sequential injection operation the injection interval between two injectors has some impact on NOx emissions and indicated specific fuel consumption(ISFC)

while the pilot injection strategy of the first and second injectors has different effects on engine performance and emissions: the former is the result of the combined effects of the pilot fuel heat release and shortened ignition delay of main injection

while the latter is mainly due to the pilot fuel heat release itself .Through the above study

the NOx emissions have been reduced by 21.27%

which proves that this method can be used to optimize the injection strategy of large marine diesel engines.