Abstract: According to one or more embodiments described herein, an exhaust system for treating exhaust gas from an internal combustion engine in a motor vehicle includes a passive NOx absorber (PNA) device, and a model-based controller that controls an amount of NOx stored by the PNA device. Controlling of the amount of NOx stored includes computing a predicted NOx storage level of the PNA device using a prediction model of the PNA device, and in response to the predicted NOx storage level of the PNA device being greater than a predetermined cold-start threshold, raising a temperature of the exhaust gas by changing an operation of the internal combustion engine.

Abstract: According to one or more embodiments described herein, an exhaust system for treating exhaust gas from an internal combustion engine in a motor vehicle includes a passive NOx absorber (PNA) device, and a model-based controller that controls an amount of NOx stored by the PNA device. Controlling of the amount of NOx stored includes computing a predicted NOx storage level of the PNA device using a prediction model of the PNA device, and in response to the predicted NOx storage level of the PNA device being greater than a predetermined cold-start threshold, raising a temperature of the exhaust gas by changing an operation of the internal combustion engine.

Abstract: A method for determining the hydrocarbon (HC) oxidation performance of an oxidation catalyst device (OC) includes communicating gas to the OC inlet over a time frame, measuring the NOx content of the OC outlet gas using a NOx sensor over the time frame, wherein the temperature of the OC increases over the time frame, and correlating an increased NOx measurement over the time frame to an increased OC HC oxidation performance. The NOx sensor can be operated in a low temperature mode during the time frame. The method can further include determining the temperature of the OC over the time frame and correlating the HC oxidation performance to the OC temperature, and/or correlating a maximum NOx concentration measured during the time frame to the OC temperature measured at the same time. HC slip through the OC can be identified when the measured NOx content of the OC outlet gas decreases.

Abstract: Technical solutions are described for limiting exposure of components of an emissions control system to rich exhaust conditions. An example an emissions control system includes an oxygen storage component; and a controller that limits exposure of the oxygen storage component to rich exhaust conditions. The limiting includes determining an air-to-fuel equivalence ratio in exhaust gas in response to an engine receiving a request to generate torque, the request including a displacement of a pedal; determining an amount of oxygen in the exhaust gas based on the air-to-fuel equivalence ratio; determining an oxygen level stored by the oxygen storage component; and if the oxygen level is above a predetermined threshold, lowering a torque generation rate of the engine, which specifies amount of torque generated per unit displacement of the pedal.

Abstract: Technical solutions are described for limiting exposure of components of an emissions control system to rich exhaust conditions. An example an emissions control system includes an oxygen storage component; and a controller that limits exposure of the oxygen storage component to rich exhaust conditions. The limiting includes determining an air-to-fuel equivalence ratio in exhaust gas in response to an engine receiving a request to generate torque, the request including a displacement of a pedal; determining an amount of oxygen in the exhaust gas based on the air-to-fuel equivalence ratio; determining an oxygen level stored by the oxygen storage component; and if the oxygen level is above a predetermined threshold, lowering a torque generation rate of the engine, which specifies amount of torque generated per unit displacement of the pedal.

Abstract: A method for determining the hydrocarbon (HC) oxidation performance of an oxidation catalyst device (OC) includes communicating gas to the OC inlet over a time frame, measuring the NOx content of the OC outlet gas using a NOx sensor over the time frame, wherein the temperature of the OC increases over the time frame, and correlating an increased NOx measurement over the time frame to an increased OC HC oxidation performance. The NOx sensor can be operated in a low temperature mode during the time frame. The method can further comprise determining the temperature of the OC over the time frame and correlating the HC oxidation performance to the OC temperature, and/or correlating a maximum NOx concentration measured during the time frame to the OC temperature measured at the same time. HC slip through the OC can be identified when the measured NOx content of the OC outlet gas decreases.

Abstract: Methods for monitoring the performance of an oxidizing catalyst device are provided. Methods can include treating an exhaust gas stream with the oxidizing catalyst device, determining a reference liberated oxygen (LO) species measurement of the exhaust gas stream, measuring a downstream LO species measurement of the exhaust gas stream using a NOx sensor in a catalyst inactive mode, and determining a LO species differential. The downstream NOx sensor can comprise an amperometric sensor and include a NO2 selective reduction catalyst. Methods for using an amperometric NOx sensor utilizing an NO2 selective reduction catalyst are also provided, and include operating the NOx sensor in a catalyst active mode to generate a first LO species measurement, operating the NOx sensor in a catalyst inactive mode to generate a second LO species measurement, and comparing the first LO species measurement to the second LO species measurement to determine a LO species differential.

Abstract: Methods for monitoring the performance of an oxidizing catalyst device are provided. Methods can include treating an exhaust gas stream with the oxidizing catalyst device, determining a reference liberated oxygen (LO) species measurement of the exhaust gas stream, measuring a downstream LO species measurement of the exhaust gas stream using a NOx sensor in a catalyst inactive mode, and determining a LO species differential. The downstream NOx sensor can comprise an amperometric sensor and include a NO2 selective reduction catalyst. Methods for using an amperometric NOx sensor utilizing an NO2 selective reduction catalyst are also provided, and include operating the NOx sensor in a catalyst active mode to generate a first LO species measurement, operating the NOx sensor in a catalyst inactive mode to generate a second LO species measurement, and comparing the first LO species measurement to the second LO species measurement to determine a LO species differential.