Patent attributes
A drive circuit (20a,20b) for an injector arrangement having at least one piezoelectric injector (12a,12b) is described. The drive circuit comprises: a first charge storage means (C2) for operative connection with the injector (12a,12b) during a discharging phase so as to discharge current to flow therethrough, thereby to initiate an injection event; a second charge storage means (C1) for operative connection with the injector (12a,12b) during a charging phase so as to cause a charging current to flow therethrough, thereby to terminate the injection event; a switch means (Q1,Q2) for controlling whether the first charge storage means (C2) is operably connected to the injector or whether the second charge storage means (C1) is operably connected to the injector; a first voltage supply rail at a first voltage level; a second voltage supply rail at a second voltage level higher than the first; a voltage supply means (22,36); and regeneration switch means (Q5,Q2, L1) operable at the end of the charging phase to transfer charge from the voltage supply means to at least the second charge storage means (C1) via an energy storage device (L1) prior to a subsequent discharging phase.
