Abstract: A system including a channel; a particulate matter sensor disposed in fluid communication with the channel, the particulate matter sensor having a sensitivity that increases in response to exposure to particulate matter; and a controller coupled to the particulate matter sensor and configured to monitor the channel in response to the sensitivity of the particular matter sensor.

Abstract: A system including a channel; a particulate matter sensor disposed in fluid communication with the channel, the particulate matter sensor having a sensitivity that increases in response to exposure to particulate matter; and a controller coupled to the particulate matter sensor and configured to monitor the channel in response to the sensitivity of the particular matter sensor.

Abstract: A method of on-board diagnostic (OBD) catalyst monitoring. Vehicle OBD exhaust systems often include a catalyst, a pre-catalyst exhaust gas oxygen sensor, and a post-catalyst exhaust gas oxygen sensor. A method is provided of monitoring the catalyst which includes the steps of measuring hydrogen or nitrogen dioxide generation by the catalyst, and correlating changes in hydrogen or nitrogen dioxide generation to changes in catalytic conversion efficiency. Because OBD legislation defines catalyst deterioration or malfunction in terms of hydrocarbon or nitrogen oxide emission levels, the method uses hydrogen or nitrogen dioxide generation as a metric for OBD monitoring of the catalyst and offers the advantage of a more direct relationship to catalyst health than conventional methods.