Method for controlling a high-pressure fuel injector

A method for controlling a high-pressure fuel injector for an internal combustion engine of a motor vehicle, the injector being provided with a solenoid for actuating a needle which opens the injector and with a spring for returning said needle to the closed position, the solenoid of the fuel injector being supplied with current by a control means comprising a first potential connected to the drain of a first transistor, the source of the first transistor being connected to the anode of a first diode, the cathode of the first diode being connected to the cathode of a second diode, to a first connector of the solenoid of the injector, and to the source of a second power transistor, the drain of a second transistor being connected to a second potential, the anode of the second diode being connected to ground, the second potential being connected to ground via a capacitance, the second potential also being connected to the cathode of a third diode, the anode of the third diode being connected to a second connector of the solenoid of the injector and to the drain of a third transistor, the source of the third transistor being connected to ground via a resistor.

• wherein the control means further comprises an additional diode connected by the additional diode's anode to the source of the second transistor, the additional diode's cathode being connected to the first connector of the injector,
• the control method comprising the following steps:
• determining whether the second potential is lower than the potential threshold allowing a current for opening the needle of the injector to be generated,
• if the second potential is lower than the potential threshold, determining whether the first potential is higher than the second potential,
• if the first potential is higher than the second potential, determining whether an injection is not required,
• if the injection is not required, controlling the transistors of the control means first so as to be a first state in which the first transistor is controlled so as to be on and the second transistor and the third transistor are controlled so as to be off and then, after detecting a solenoid charging current greater than a reference current through the first transistor, the transistors are controlled so as to be in a second state in which the first transistor, the second transistor and the third transistor are controlled so as to be off so as to obtain a charge transfer effect between the input first potential and the second potential,
• waiting a predetermined time to allow the solenoid to discharge,
• determining whether the second potential is lower than the potential threshold allowing a current for opening the needle of the injector to be generated,
• if the second potential is lower than the potential threshold, returning to charging the solenoid of the injector.