Abstract: Methods and systems are provided for a NOx sensor. In one example, a method includes heating a NOx sensor during a vehicle off in response to a cumulative heat energy applied to the NOx.

Abstract: Methods and systems are provided for a NOx sensor. In one example, a method includes heating a NOx sensor during a vehicle off in response to a cumulative heat energy applied to the NOx.

Abstract: Methods and systems for operating an engine that includes a controller and a NOx sensor are described. In one example, output of the NOx sensor is selectively made available to software modules within the controller when an offset in NOx sensor output is not expected. If the offset in NOx sensor output is expected, the NOx sensor output may not be made available to the software modules.

Abstract: Methods and systems for operating an engine that includes a controller and a NOx sensor are described. In one example, output of the NOx sensor is selectively made available to software modules within the controller when an offset in NOx sensor output is not expected. If the offset in NOx sensor output is expected, the NOx sensor output may not be made available to the software modules.

Abstract: Methods and systems are provided for identifying when an exhaust valve of an engine cylinder is not functioning as desired while the engine is being operated to raise a temperature of an exhaust system emissions control device, and in turn taking mitigating action. Thus, in one example a method comprises adjusting an amount of fuel that is provided to each of a plurality of cylinders of an engine during an exhaust stroke of the engine in response to an indication of degraded combustion stemming from a cylinder of the engine. In this way, the engine may continue to be operated to raise the temperature of the exhaust system emissions control device, while mitigating the issue of the degraded combustion.

Abstract: Methods and systems are provided for identifying when an exhaust valve of an engine cylinder is not functioning as desired while the engine is being operated to raise a temperature of an exhaust system emissions control device, and in turn taking mitigating action. Thus, in one example a method comprises adjusting an amount of fuel that is provided to each of a plurality of cylinders of an engine during an exhaust stroke of the engine in response to an indication of degraded combustion stemming from a cylinder of the engine. In this way, the engine may continue to be operated to raise the temperature of the exhaust system emissions control device, while mitigating the issue of the degraded combustion.

Abstract: Various systems and methods are described for detecting ammonia slip. In one example method, an exhaust system with two NOx sensors uses transient responses of the NOx sensors to allocate tailpipe NOx sensor output to NOx and NH3 levels therein. An ammonia slip detection counter with gains is included that determines a probability of NOx and NH3 based on the measured sensor activities that are further processed by a controller to adjust one or more parameters based on the allocation and changes of sensor output.

Abstract: The systems and method described above in the present disclosure allow for regeneration of a diesel particulate filter while a vehicle is in stationary power take-off mode. Described is a method of: during select power take-off conditions, reducing an EGR rate responsive to an indication to regenerate a diesel particulate filter.

Abstract: A method for controlling combustion in an engine is provided. The method comprises under a first condition, adjusting an EGR amount of a total cylinder charge in response to engine out NOx levels being below a first threshold. In this way, NOx levels may be used as feedback to control combustion stability.

Abstract: Various systems and methods are described for detecting ammonia slip. In one example method, an amount of exhaust gas recirculation is reduced when output from an exhaust gas sensor indicates an increase in nitrogen oxide above a threshold amount. When the sensor output increases above a second threshold while the exhaust gas recirculation is reduced, the sensor output is allocated to nitrogen oxide; and when the sensor output does not increase above a second threshold while the exhaust gas recirculation is reduced, the sensor output is allocated to ammonia.

Abstract: The systems and method described above in the present disclosure allow for regeneration of a diesel particulate filter while a vehicle is in stationary power take-off mode. Described is a method of: during select power take-off conditions, reducing an EGR rate responsive to an indication to regenerate a diesel particulate filter.

Abstract: Various systems and methods are described for detecting ammonia slip. In one example method, an exhaust system with two NOx sensors uses transient responses of the NOx sensors to allocate tailpipe NOx sensor output to NOx and NH3 levels therein. An ammonia slip detection counter with gains is included that determines a probability of NOx and NH3 based on the measured sensor activities that are further processed by a controller to adjust one or more parameters based on the allocation and changes of sensor output.

Abstract: Various systems and methods are described for detecting ammonia slip. In one example method, an amount of exhaust gas recirculation is reduced when output from an exhaust gas sensor indicates an increase in nitrogen oxide above a threshold amount. When the sensor output increases above a second threshold while the exhaust gas recirculation is reduced, the sensor output is allocated to nitrogen oxide; and when the sensor output does not increase above a second threshold while the exhaust gas recirculation is reduced, the sensor output is allocated to ammonia.

Abstract: A method for responding to an existing or incipient surge condition of a turbocharger coupled to an engine of a motor vehicle is provided. The method comprises receiving a signal responsive to an operating condition of the turbocharger and adjusting one or more operating parameters of the motor vehicle when a power of the signal, integrated over a pre-selected range of non-zero frequencies, exceeds a pre-selected threshold. Other embodiments provide related systems for responding to an existing or incipient surge condition of a turbocharger.

Abstract: A method for controlling combustion in an engine is provided. The method comprises under a first condition, adjusting an EGR amount of a total cylinder charge in response to engine out NOx levels being below a first threshold. In this way, NOx levels may be used as feedback to control combustion stability.

Abstract: A method for responding to an existing or incipient surge condition of a turbocharger coupled to an engine of a motor vehicle is provided. The method comprises receiving a signal responsive to an operating condition of the turbocharger and adjusting one or more operating parameters of the motor vehicle when a power of the signal, integrated over a pre-selected range of non-zero frequencies, exceeds a pre-selected threshold. Other embodiments provide related systems for responding to an existing or incipient surge condition of a turbocharger.

Abstract: A method for responding to an existing or incipient surge condition of a turbocharger coupled to an engine of a motor vehicle is provided. The method comprises receiving a signal responsive to an operating condition of the turbocharger and adjusting one or more operating parameters of the motor vehicle when a power of the signal, integrated over a pre-selected range of non-zero frequencies, exceeds a pre-selected threshold. Other embodiments provide related systems for responding to an existing or incipient surge condition of a turbocharger.

Abstract: A system and method for controlling an engine control an EGR cooler bypass valve to divert at least a portion of EGR flow around an EGR cooler when operating under cooler fouling/plugging conditions, such as during idle, off-idle, exhaust system warm up and DPF regeneration or other post injection operation with EGR gas temperature below a corresponding threshold or with EGR low-temperature coolant temperature below a corresponding threshold. The system and method reduce exhaust gases passing through the EGR cooler that contain a high concentration of unburned or partially unburned fuel when the temperature in the EGR system is lower than the fuel condensation temperature.

Abstract: A system and method for controlling an engine control an EGR cooler bypass valve to divert at least a portion of EGR flow around an EGR cooler when operating under cooler fouling/plugging conditions, such as during idle, off-idle, exhaust system warm up and DPF regeneration or other post injection operation with EGR gas temperature below a corresponding threshold or with EGR low-temperature coolant temperature below a corresponding threshold. The system and method reduce exhaust gases passing through the EGR cooler that contain a high concentration of unburned or partially unburned fuel when the temperature in the EGR system is lower than the fuel condensation temperature.

Abstract: A method for responding to an existing or incipient surge condition of a turbocharger coupled to an engine of a motor vehicle is provided. The method comprises receiving a signal responsive to an operating condition of the turbocharger and adjusting one or more operating parameters of the motor vehicle when a power of the signal, integrated over a pre-selected range of non-zero frequencies, exceeds a pre-selected threshold. Other embodiments provide related systems for responding to an existing or incipient surge condition of a turbocharger.