| 摘要 |
<p>A fault detection method for detecting short circuit faults in an injector arrangement at engine start-up. The injector arrangement comprises piezoelectric fuel injectors (12a,12b) which are connected in a drive circuit (20). The potential (VB) at a bias point (PB) in the drive circuit (20) is determined and compared with a predicted voltage (VPB). A short circuit fault signal is generated if the potential (VB) at the bias point (PB) is not within a predetermined tolerance voltage (VTOL) of the predicted voltage (VPB). Furthermore, a discharge current path (38) is provided during a delay period (”t) following a first charge pulse, by closing a discharge switch (Q2). A faulty injector (12a,12b) will then discharge through the discharge current path (38). A second charge pulse is applied to the injectors (12a,12b) following the delay period (”t). A short circuit warning signal is generated if the current flow (IS) during the second charge pulse exceeds a predetermined threshold current.</p> |
