Differential pressure-based enablement of a particulate filter diagnostic

A method comprising:

• measuring, via sensor, an instantaneous differential pressure across a particulate filter in an exhaust stream of an engine;
• receiving, via a controller, the measured instantaneous differential pressure from the sensor;
• and
• selectively enabling or disabling execution of an efficiency diagnostic of the particulate filter as a function of the instantaneous differential pressure, including enabling execution of the efficiency diagnostic when a differential pressure offset value of the sensor is less than a calibrated differential pressure offset value and disabling the execution when the differential pressure offset value of the sensor exceeds the calibrated differential pressure offset value.

A method comprising:

• measuring an instantaneous differential pressure across a diesel particulate filter (DPF) in an exhaust stream of a diesel engine using a sensor;
• receiving, via a controller, the measured instantaneous differential pressure from the sensor;
• detecting a key-off event of the engine;
• selectively enabling or disabling execution of an efficiency diagnostic of the DPF as a function of the measured instantaneous differential pressure only when the key-off event is detected, including:
• waiting through a calibrated settling time after detecting the key-off event;
• comparing the measured instantaneous differential pressure to a calibrated threshold;
• executing a first control action when the measured instantaneous differential pressure is within an allowable range of the calibrated threshold, including:
• applying a differential pressure offset value to the measured differential pressure to thereby zero the sensor;
• and
• enabling the execution of the particulate filter efficiency diagnostic using measurements from the zeroed sensor;
• and
• executing a second control action when the measured instantaneous differential pressure is not within the allowable range of the threshold, including:
• disabling the execution of the DPF efficiency diagnostic;
• and
• setting a diagnostic code indicating that the sensor is faulty.