Sensitivity analysis of the dynamic response of an electronic fuel injector regarding fuel properties and operating conditions

The sensitivity of fuel properties to the dynamic response (needle valve opening/closing delay and needle valve opening/closing time) of a electronic fuel injector was investigated. The fuel properties in different operating conditions were varied individually in bulk modulus, density and viscosity. Firstly, an electronic fuel injector model was built and validated by injection rate and injection mass at three different rail pressures and three different activation times. Secondly, a DOE (design of experiment) model was built and the Uniform Latin Hypercube (ULH) design method was applied to study the influences of the fuel properties on the injector dynamic response from a statistical point of view. The effects of the fuel properties were compared by using a SS-ANOVA (smoothing spline analysis of variance) method at both a low and a high rail pressure. The bulk modulus was found to play a dominant role in influencing the valve opening/closing delay at the low rail pressure. However, at the high rail pressure, the effects of the viscosity are prominent, while the effects of the bulk modulus and the density are negligible. Additionally, how these fuel properties affect the dynamic response were reported by RSM (Response Surface Method) function charts, and the details of the pressure differences and needle valve movements were also disclosed.