Abstract: The invention relates to a drive circuit for an injector arrangement having a fuel injector, and a method of detecting faults in the drive circuit. The drive circuit includes a diagnostic tool that senses a measured voltage between the injector and a known voltage level. The measured voltage is biased with respect to the known voltage to a predicted voltage unless the drive circuit has a fault. A fault signal is provided on sensing of a measured voltage that differs from the predicted voltage. The drive circuit may additionally, or alternatively, include a diagnostic tool. The diagnostic tool senses a detected current to provide a fault signal upon detection of the fault when the detected current is at variance from a threshold current.

Abstract: The invention relates to a drive circuit for an injector arrangement comprising a fuel injector, and method of detecting faults in the drive circuit. The drive circuit comprises diagnostic means (RH, RL) that is operable to sense a measured voltage (VBIAS) between the injector and a known voltage level (VBAT, VGND). The measured voltage (VBIAS) is biased with respect to the known voltage (VBAT, VGND) to a predicted voltage (VPinjN, VBcalc) unless the drive circuit has a fault. A fault signal is provided on sensing of a measured voltage (VBIAS) that differs from the predicted voltage (VPinjN, VBcalc). The drive circuit may additionally, or alternatively, comprise diagnostic means (RF). The diagnostic means (RF) is operable to sense a detected current (Idect) and to provide a fault signal on detection of a fault, when the detected current (Idect) is at variance from a threshold current (Itrip).

Abstract: A drive circuit is provided in a full H-bridge and half H-bridge configuration for controlling one or more piezoelectric fuel injectors. The drive circuit includes a voltage input for receiving a voltage signal, an energy storage device coupled to the voltage input for storing an electrical charge, a bidirectional current path coupled to one or more piezoelectric injectors, an inductor coupled in series with the piezoelectric injector(s) in the bidirectional current path, and switching circuitry for controlling current flow through the piezoelectric injector(s) and the inductor to open and close the piezoelectric injector(s). The switching circuitry is controlled to provide a recirculation current to recover energy stored in the piezoelectric injector(s) for storage in the energy storage device.

Abstract: A drive circuit is provided in a full H-bridge and half H-bridge configuration for controlling one or more piezoelectric fuel injectors. The drive circuit includes a voltage input for receiving a voltage signal, an energy storage device coupled to the voltage input for storing an electrical charge, a bidirectional current path coupled to one or more piezoelectric injectors, an inductor coupled in series with the piezoelectric injector(s) in the bidirectional current path, and switching circuitry for controlling current flow through the piezoelectric injector(s) and the inductor to open and close the piezoelectric injector(s). The switching circuitry is controlled to provide a recirculation current to recover energy stored in the piezoelectric injector(s) for storage in the energy storage device.