摘要 |
The disclosure provides a method, system and internal combustion engine system in which a closed-loop system having a controllable variable is monitored to detect the off-nominal behavior of the closed-loop system and raise an alarm or other alerting mechanism when fault is detected. The faults in a closed-loop system show up in such a way that the tracking error signal is impacted and this impact manifests itself as a change in the frequency components. A filter is used to isolate a band of frequency components of the tracking error signal that are more impacted than other by deviation caused by a fault to be detected. The filter can be designed to effectively amplify the section of the error tracking signal that contains the frequency components that have the major impact. In addition, the filter will also have the characteristics to attenuate the impact of other frequency components. An accumulated error signal is generated from the filtered tracking error signal, compared with a predetermined fault threshold characteristic, and a fault indication/warning/alert is provided for the closed-loop system if the accumulated error signal meets the predetermined threshold. |