Research on the correlation between fuel injection quantity and key structural parameters for the fuel system of marine diesel engines

Abstract

In order to demonstrate the relationship between the fuel injection quantity and the structural parameters of the fuel system for large marine diesel engines, an AMESim model of a double-valve controlled fuel system is proposed. The accuracy of the model is validated in view of fuel injection quantity and system pressures. The correlation analysis is performed to illustrate the effects of single parameters and the interactions between different parameters on the fuel injection quantity. Considering the high calculation cost of the simulation model, the prediction model between the fuel injection quantity and the structural parameters for each working condition is obtained based on D-optimal design of experiments and the response surface methodology in this article. For the maximum deviation between the calculated and predicted fuel injection quantity is only 4.27%, the prediction models could be used for further analysis. And the results show that the diameters of high-pressure fuel tube (HPFT), small and big ends of pressure amplification piston (PAP) are the key single parameters. The absolute values of their correlation coefficients are between 0.77 and 0.87, between 0.22 and 0.43 and between 0.14 and 0.26 respectively. The correlation coefficients for the other parameters are all relatively small. For interactive parameters, the absolute values for all the correlation coefficients are less than 0.1. And the interactions between the diameters of big and small diameters of PAP, between the diameter of small end of PAP and the diameter of HPFT, between the diameter of HPFT and the pre-tightening force of needle spring influence the fuel injection quantity relatively obviously.