Abstract: A control method for monitoring a selective catalytic reduction (“SCR”) device is provided. A control method includes adjusting an existing efficiency threshold based on a dosing adaptation value to determine an efficiency threshold. The dosing adaptation value represents an adjusted value of a supply of reductant based on a determined deviation of a downstream NOx concentration value to an expected NOx concentration. The control method includes comparing the efficiency threshold with a determined efficiency of the SCR device. The control method includes generating a message based on comparing the efficiency threshold with the determined efficiency of the SCR device.

Abstract: The capacity of a platinum-containing diesel oxidation catalyst (DOC) to simultaneously convert NO to NO2, CO to carbon dioxide, and remaining hydrocarbons to carbon dioxide and water in the exhaust system of a vehicle diesel engine may be evaluated and diagnosed using measured DOC exhaust inlet temperatures and outlet temperatures at a relatively high exhaust temperature and, soon thereafter, at a relatively low exhaust inlet temperature. Values of the platinum-containing DOC exotherms at the high and low DOC inlet temperatures are found to provide a basis for evaluation of both NO conversion and the HC and CO conversion capabilities of the DOC. The process may be repeated as the catalyzed DOC conversion efficiency changes with use. The practice may also be used to evaluate the performance of oxidation catalysts used in a like way in treating the exhaust from a lean-burn gasoline engine.

Abstract: A system for a vehicle includes a regeneration module and a disconnection indication module. The regeneration module indicates when a regeneration of a particulate filter is complete. The disconnection indication module receives a pressure difference across the particulate filter measured using delta pressure sensor. The delta pressure sensor generates the pressure difference based on first and second pressures upstream and downstream of the particulate filter applied to the delta pressure sensor using upstream and downstream pressure lines, respectively. In response to an indication that the regeneration of the particulate filter is complete, the disconnection indication module selectively indicates that the downstream pressure line is disconnected based on a comparison of the pressure difference and a predetermined pressure.

Abstract: A method of monitoring a sensor of an exhaust system is provided. The method includes evaluating humidity of air entering the exhaust system; and monitoring operation of a sensor in the exhaust system based on the humidity.

Abstract: A method of monitoring regeneration of a particulate filter is provided. The method includes evaluating whether a regeneration event is based on a fixed threshold condition; selectively setting a pass or fail status based on the evaluating; and generating a message indicating the pass or fail status.

Abstract: A system for a vehicle includes a regeneration module and a disconnection indication module. The regeneration module indicates when a regeneration of a particulate filter is complete. The disconnection indication module receives a pressure difference across the particulate filter measured using delta pressure sensor. The delta pressure sensor generates the pressure difference based on first and second pressures upstream and downstream of the particulate filter applied to the delta pressure sensor using upstream and downstream pressure lines, respectively. In response to an indication that the regeneration of the particulate filter is complete, the disconnection indication module selectively indicates that the downstream pressure line is disconnected based on a comparison of the pressure difference and a predetermined pressure.

Abstract: A method of assessing overall efficiency of a selective-catalytic-reduction catalyst includes monitoring instantaneous efficiency of the catalyst. The method also includes determining the overall efficiency by summing instantaneous efficiency values weighted by a first set of coefficients if the most recent instantaneous efficiency value is above an instantaneous efficiency threshold. The method additionally includes determining the overall efficiency by summing instantaneous efficiency values weighted by a second set of coefficients if the most recent instantaneous efficiency value is equal to or below the instantaneous efficiency threshold. Furthermore, the method includes determining whether the overall efficiency has dropped below an overall efficiency threshold and reporting when the overall efficiency has dropped below the overall efficiency threshold.

Abstract: A vehicle includes an engine having an exhaust port, an exhaust system for conditioning an engine exhaust stream, a nitrogen oxide (NOx) sensor positioned within the exhaust stream, and a controller. The controller has an out-of-range diagnostic tool for evaluating a range performance of the sensor. The controller detects a predetermined engine-on fuel shutoff event, and then temporarily disables the diagnostic tool during the fuel shutoff event. The fuel shutoff event may be a vehicle deceleration-based event. A selective catalytic reduction (SCR) device may be positioned within the exhaust system, with at least one NOx sensor positioned at the outlet of the SCR device. An additional NOx sensor may be positioned in proximity to the exhaust port. A method for use aboard the above vehicle includes detecting the engine-on fuel shutoff event via the controller, and temporarily disabling the diagnostic tool for the duration of the detected fuel shutoff event.