Research On Characteristics Of High-Speed Solenoid Valve For Diesel Engine Electronic Unit Pump

Electronic unit pump (EUP) is a time controlled fuel injection system which is used ondiesel engine to meet emissions regulations and improve the fuel economy. High-speedsolenoid valve is one of its key components because the performances of its strongelectromagnetic force and rapid response determine the flexible fuel injection law for EUP.The controlling of injection timing and injection quantity can be achieved through adjustmentclosing time and closed time length of high-speed solenoid valve, so the fuel injection processachieve digital control. Therefore, carrying out research work of high-speed solenoid valvecharacteristic, getting the influence law of some factors for solenoid valve characteristic, hasthe vital significance for the optimal design of high-speed solenoid valve and to speed upindependent development of diesel engine electronic fuel injection (EFI) technology. In thispaper, we aim at high-speed solenoid valve for a type of EUP, the static electromagnetic forceand dynamic response characteristics are in-depth studied. The main research works carriedout in the paper are as follows:First, the3D static and transient magnetic field solving finite element model ofhigh-speed solenoid valve is established in Ansoft environment. The accuracy of the model isvalidated by comparing to the experiment results and the electromagnetic force maximumdeviation is9%, the response time maximum deviation is0.06ms in the closing stages, theresponse time maximum deviation is0.14ms in the opening stages.Second, the parameters change of iron core, winding, armature, assembly and control onthe influence of the electromagnetic force have been studied by static simulation model. It isconcluded that iron core material, the ratio of iron core main and auxiliary polecross-sectional area, excitation coil turns, working air gap, drive current and armaturethickness are the main influence factors on electromagnetic force. Through quantitativeanalysis, the percentage quantitative indexes and its changing laws of the influence of thedifferent parameters such as pole length, coil turns, coil position, armature thickness, dampingorifice position, damping orifice size on electromagnetic force are obtained in the overalloperating conditions. Third, in order to further study the various factors on the influence of electromagneticforce, by using the design of experiments (DOE) and partial least squares (PLS) method,regression model of the electromagnetic force and correlation between various factors andelectromagnetic force are received when the parameters are non-interactive and interactive.The result shows that not only the single factor but also the interaction factor of variousinfluence parameters has correlation with the electromagnetic force. Through correlateanalysis in the overall operating conditions, the correlation coefficient has been obtainedbetween different parameters such as pole length, coil turns, coil position, armature thickness,damping orifice position, damping orifice size and electromagnetic force in differentoperating points.Finally, the parameters change of driving voltage, moving parts mass, residual air gap,reset spring preload, spring stiffness on the influence of the closing process have been studiedby transient simulation model. It is concluded that the closing time for solenoid valve isaffected by driving voltage heavily, followed by spring preload, residual air gap, moving partsmass, in that order, spring stiffness least. By using the DOE and PLS method, regressionmodel of pull-in actuation time, pull-in movement time, the closing time and correlationbetween various factors and these time are received when the parameters are interactive.