Abstract: Systems and methods for detecting ammonia slip in an exhaust system based upon transient NOx sensor responses are described. In one example method, an exhaust system allocates tailpipe NOx sensor output to NOx and NH3 levels responsive to the transient sensors using a segment length method that processes the transient signals based on the total segment lengths calculated within a window. A ratio of segment lengths relative to a threshold is determined for a measured and expected NOx rate of change downstream of an SCR that is further used to determine a probability of NOx and NH3 based on the measured sensor activities, and a controller is included to adjust one or more parameters based on the allocation and changes of sensor output.

Abstract: Systems and methods for detecting ammonia slip in an exhaust system based upon transient NOx sensor responses are described. In one example method, an exhaust system allocates tailpipe NOx sensor output to NOx and NH3 levels responsive to the transient sensors using a segment length method that processes the transient signals based on the total segment lengths calculated within a window. A ratio of segment lengths relative to a threshold is determined for a measured and expected NOx rate of change downstream of an SCR that is further used to determine a probability of NOx and NH3 based on the measured sensor activities, and a controller is included to adjust one or more parameters based on the allocation and changes of sensor output.

Abstract: A control system and method for controlling an engine (10) of an automotive vehicle having a catalyst (34) and controller (40) is set forth herein. The controller (40) is configured to determine a first exhaust flow rate and a second exhaust flow rate based on a flow rate of the exhaust gases. The controller is further configured to determine a first temperature (T1) of exhaust gases associated with the first exhaust flow rate based on a steady state temperature and an amount of heat transferred from the exhaust gases associated with the first exhaust flow rate to an exhaust system. The controller is further configured to determine a second temperature of exhaust gases associated with the second exhaust flow rate based on the steady state temperature. The controller is further configured to determine the catalytic converter temperature based on the first temperature and the second temperature.

Abstract: A control system and method for controlling an engine (10) of an automotive vehicle having a catalyst (34) and controller (40) is set forth herein. The controller (40) is configured to determine a first exhaust flow rate and a second exhaust flow rate based on a flow rate of the exhaust gases. The controller is further configured to determine a first temperature (T1) of exhaust gases associated with the first exhaust flow rate based on a steady state temperature and an amount of heat transferred from the exhaust gases associated with the first exhaust flow rate to an exhaust system. The controller is further configured to determine a second temperature of exhaust gases associated with the second exhaust flow rate based on the steady state temperature. The controller is further configured to determine the catalytic converter temperature based on the first temperature and the second temperature.