The Optimal Drive Current of Solenoid Valve and Its Effect on Fuel Injection Characteristics

The existence of the holding and firing current critical values that maintain the solenoid valve´s armature in a pick-up state exactly are discovered, and analyzed from the perspective of the electromagnetic and motion characteristics. Validation of the optimal holding and firing value of 2A and 11A took place on the Delphi E1 EUP. At the same time, different solenoid valve drive currents and their effects on fuel injection characteristics are analyzed. The results show that different drive currents are equal to the change injection duration of fuel injection system because of the existence of critical value of holding current Ih.th and firing current Io.th. The pick-up duration of the armature is longer, and the pick-up velocity is slower when the firing current peak value is lower than the critical firing current peak value Io.th. The experimental results indicate that different drive currents have an influence on fuel injection characteristics. Consequently, all solenoid valves need to search for the optimal holding-current and firing-current peak values in order to minimize the influence on the fuel injection characteristics.