Correlation analysis upon the influential factors related to the dynamic response characteristics of pressure amplification piston in the fuel system for a low-speed diesel engine

Abstract

Response characteristics are the key index to measure the performance of diesel engine fuel system. In this study, a simulation model of double-valve controlled common rail fuel system for low-speed diesel engine was presented. The accuracy of the model was fully validated by comparing calculation results with experimental data. Since the motion of pressure amplification piston (PAP) is highly correlated to fuel injection performance, the dynamic response of PAP was investigated. To determine the key factors influencing PAP dynamic response characteristics, a correlation analysis upon the structural parameters influencing opening response time (ORT) and closing response time (CRT) of PAP was performed based on the validated model. The results show that the change of working condition has a great effect on the opening process of PAP, but has little on closing process. Among all the isolated factors, the diameters of fuel plunger, high-pressure fuel tube and nozzle hole are the crucial factors related to the ORT of PAP. The diameters of fuel plunger, hydraulic piston and high-pressure fuel tube influence the CRT of PAP significantly. Among all the quadratic factors, the effects of interactions between diameter of fuel plunger and diameter of high-pressure fuel tube and between diameter of fuel plunger and diameter of nozzle hole on the ORT of PAP could not be neglected. The interactions between diameter of fuel plunger and diameter of high-pressure fuel tube and the interaction between diameter of high-pressure fuel tube and diameter of nozzle hole make great contribution to the CRT of PAP.