Abstract: A lean-burn internal combustion engine and an exhaust aftertreatment system having an oxidation catalyst are described. A controller determines a fueling rate and a mass flowrate of the exhaust gas feedstream. An inlet temperature of the exhaust gas feedstream upstream of the oxidation catalyst is determined via the first temperature sensor, and an in-use outlet temperature of the exhaust gas feedstream is determined downstream of the oxidation catalyst via the second temperature sensor. An expected outlet temperature from the oxidation catalyst is determined based upon the inlet temperature, the fueling rate, and the mass flowrate of the exhaust gas feedstream. The oxidation catalyst is evaluated based upon the expected outlet temperature and the in-use outlet temperature.

Abstract: The present disclosure describes methods for evaluating quality of DEF dosed to an EAS including a close coupled SCR unit a downstream SCR unit. A NOx conversion efficiency of the close coupled SCR unit and a NOx conversion efficiency of the downstream SCR unit are used to evaluate quality of DEF. In some embodiments, the NOx conversion efficiency of close coupled SCR unit is used to evaluate quality of DEF. Operation of an EAS using the results of the evaluation of quality of DEF are described.

Abstract: A heavy duty truck includes a diesel engine that generates an exhaust gas flow and an exhaust after-treatment system for treatment of the exhaust gas flow. The exhaust after-treatment system includes at least one heater and at least one selective catalytic reduction system downstream of the heater. The heater is operated to inject supplemental heat energy into the exhaust gas flow at a rate based on a difference between a target rate of heat energy in the exhaust gas flow at an inlet to the selective catalytic reduction system and a rate of heat energy supplied to the exhaust gas flow from the diesel engine.

Abstract: A heavy duty truck includes a diesel engine that generates an exhaust gas flow and an exhaust after-treatment system for treatment of the exhaust gas flow. The exhaust after-treatment system includes at least one temperature sensor at an underbody SCR system within the exhaust after-treatment system and a DEF injector upstream of a close-coupled SCR system within the exhaust after-treatment system. The DEF injector is operated to inject DEF into the exhaust gas flow at a rate that varies as a function of a temperature measured by the temperature sensor.

Abstract: Controlling exhaust after-treatment in a heavy-duty motor vehicle includes operating a diesel engine of a heavy-duty truck such that the diesel engine generates an exhaust gas flow that enters an exhaust after-treatment system of the heavy-duty truck, the exhaust after-treatment system including a selective catalytic reduction system, measuring a level of NOx gases in the exhaust gas flow downstream of the selective catalytic reduction system, and controlling a diesel exhaust fluid injector upstream of the selective catalytic reduction system to inject diesel exhaust fluid into the exhaust gas flow upstream of the selective catalytic reduction system at an injection rate that is based on the measured level of NOx gases.

Abstract: A heavy-duty truck has a diesel engine, an exhaust after-treatment system, and an engine control unit. The exhaust after-treatment system includes a close-coupled selective catalytic reduction system and an underbody selective catalytic reduction system, a first NOx sensor upstream of the close-coupled selective catalytic reduction system, a second NOx sensor between the two selective catalytic reduction systems, and a third NOx sensor downstream of the underbody selective catalytic reduction system. The engine control unit may perform methods allowing intrusive diagnostics to be performed on exhaust gas NOx sensors using the selective catalytic reduction systems during normal operation of the heavy-duty truck.

Abstract: Controlling exhaust after-treatment in a heavy-duty motor vehicle includes operating a diesel engine of a heavy-duty truck such that the diesel engine generates an exhaust gas flow that enters an exhaust after-treatment system of the heavy-duty truck, the exhaust after-treatment system including a selective catalytic reduction system, measuring a level of NOx gases in the exhaust gas flow downstream of the selective catalytic reduction system, and controlling a diesel exhaust fluid injector upstream of the selective catalytic reduction system to inject diesel exhaust fluid into the exhaust gas flow upstream of the selective catalytic reduction system at an injection rate that is based on the measured level of NOx gases.

Abstract: Aspects of systems, method, and computer-readable storage media are described herein that are configured to provide operator fleet performance benchmarking and analytics. A fleet analytics system may include user-friendly front end client application with which a non-technical user may interface, and a back end analytics and visualization system that is deployed on the cloud and offered as a service to determine a subset of ‘like operators’ to utilize as a baseline in a benchmark analysis, to benchmark a target operator's performance against the subset of like operators, determine analytics resulting from the benchmark analysis, and to generate visualizations of the analytics for display to the user/operator.

Abstract: A modular exhaust subsystem for purifying an exhaust gas feedstream of a compression-ignition internal combustion engine upstream of a base exhaust aftertreatment system includes a selective catalytic reduction (SCR) catalyst, and a first exhaust gas sensor and a first temperature sensor that are arranged to monitor the SCR catalyst. A reductant delivery system is arranged to inject a reductant upstream of the SCR catalyst. A controller is in communication with an engine-out exhaust gas sensor, a second exhaust gas sensor and a second temperature sensor that are arranged to monitor the base exhaust aftertreatment system. The controller controls the reductant delivery system to inject the reductant into the exhaust gas feedstream upstream of the SCR catalyst based upon inputs from the first and second exhaust gas sensors, the engine-out exhaust gas sensor, and the first and second temperature sensors.

Abstract: Methods of improving SCR performance in heavy duty vehicles may use multiple interdependent control techniques to increase engine exhaust temperatures in a fuel efficient manner. One method combines cylinder deactivation and mechanical loading of an engine by an electrical generator used to input energy into an exhaust stream to manipulate the exhaust temperature through the combined effect of modified air-to-fuel ratio and supplemental energy input. In particular, cylinder deactivation may be used to modify the engine air flowrate and the electric generator may be used to apply mechanical load on the engine to manipulate the engine fuel flow rate to control the engine air-to-fuel ratio and thereby increase exhaust temperatures. The exhaust temperatures may be further increased by using the electrical generator to add the energy generated as input energy to the exhaust stream.

Abstract: A heavy duty truck includes a diesel engine that generates an exhaust gas flow and an exhaust after-treatment system for treatment of the exhaust gas flow. The exhaust after-treatment system includes at least one heater and at least one selective catalytic reduction system downstream of the heater. The heater is operated to inject supplemental heat energy into the exhaust gas flow at a rate based on a difference between a target rate of heat energy in the exhaust gas flow at an inlet to the selective catalytic reduction system and a rate of heat energy supplied to the exhaust gas flow from the diesel engine.

Abstract: A heavy duty truck includes a diesel engine that generates an exhaust gas flow and an exhaust after-treatment system for treatment of the exhaust gas flow. The exhaust after-treatment system includes at least one temperature sensor at an underbody SCR system within the exhaust after-treatment system and a DEF injector upstream of a close-coupled SCR system within the exhaust after-treatment system. The DEF injector is operated to inject DEF into the exhaust gas flow at a rate that varies as a function of a temperature measured by the temperature sensor.

Abstract: Embodiments are directed towards controlling uncontrolled release of ammonia from an engine of a vehicle. An estimated status of the engine is determined prior to an event, such as an estimated load on the engine prior to the vehicle going up a hill. A predictive model of uncontrolled ammonia release is generated for the estimated status. At least one engine-related countermeasure is selected based on the predictive model. If the predictive model of uncontrolled ammonia release with the selected countermeasures satisfies a threshold condition, then the selected engine-related countermeasure is employed.

Abstract: A lean-burn internal combustion engine and an exhaust aftertreatment system having an oxidation catalyst are described. A controller determines a fueling rate and a mass flowrate of the exhaust gas feedstream. An inlet temperature of the exhaust gas feedstream upstream of the oxidation catalyst is determined via the first temperature sensor, and an in-use outlet temperature of the exhaust gas feedstream is determined downstream of the oxidation catalyst via the second temperature sensor. An expected outlet temperature from the oxidation catalyst is determined based upon the inlet temperature, the fueling rate, and the mass flowrate of the exhaust gas feedstream. The oxidation catalyst is evaluated based upon the expected outlet temperature and the in-use outlet temperature.

Abstract: The present disclosure describes methods for evaluating ammonia storage capacity of a close-coupled SCR unit while remaining compliant with prescribed emissions limits, methods of controlling an emission aftertreatment system including multiple SCR units and emission management systems for a vehicle including an internal combustion engine and an emission aftertreatment system that includes two or more SCR units.

Abstract: Embodiments are directed towards controlling uncontrolled release of ammonia from an engine of a vehicle. An estimated status of the engine is determined prior to an event, such as an estimated load on the engine prior to the vehicle going up a hill. A predictive model of uncontrolled ammonia release is generated for the estimated status. At least one engine-related countermeasure is selected based on the predictive model. If the predictive model of uncontrolled ammonia release with the selected countermeasures satisfies a threshold condition, then the selected engine-related countermeasure is employed.

Abstract: The present disclosure describes methods for evaluating quality of DEF dosed to an EAS including a close coupled SCR unit a downstream SCR unit. A NOx conversion efficiency of the close coupled SCR unit and a NOx conversion efficiency of the downstream SCR unit are used to evaluate quality of DEF. In some embodiments, the NOx conversion efficiency of close coupled SCR unit is used to evaluate quality of DEF. Operation of an EAS using the results of the evaluation of quality of DEF are described.

Abstract: An exhaust aftertreatment system and associated system for purifying an exhaust gas feedstream of a lean-burn engine includes an oxidation catalyst that is arranged upstream of a selective catalytic reduction (SCR) catalyst. A first NOx sensor is arranged upstream, and a second NOx sensor is arranged downstream of the oxidation catalyst. A controller is arranged to monitor the oxidation catalyst based upon inputs from the first and second NOx sensors. A first NOx parameter is determined via the first NOx sensor, and a second NOx parameter is determined via the second NOx sensor. An NO2 parameter is determined based upon the first NOx parameter, the second NOx parameter, a first relationship for the first and second NOx sensors, and a second relationship for the first and second NOx sensors. The NO2 production of the oxidation catalyst is evaluated based upon the NO2 parameter.

Abstract: Methods of improving SCR performance in heavy duty vehicles may use multiple interdependent control techniques to increase engine exhaust temperatures in a fuel efficient manner. One method combines cylinder deactivation and mechanical loading of an engine by an electrical generator used to input energy into an exhaust stream to manipulate the exhaust temperature through the combined effect of modified air-to-fuel ratio and supplemental energy input. In particular, cylinder deactivation may be used to modify the engine air flowrate and the electric generator may be used to apply mechanical load on the engine to manipulate the engine fuel flow rate to control the engine air-to-fuel ratio and thereby increase exhaust temperatures. The exhaust temperatures may be further increased by using the electrical generator to add the energy generated as input energy to the exhaust stream.

Abstract: A heavy duty truck includes a diesel engine that generates an exhaust gas flow and an exhaust after-treatment system for treatment of the exhaust gas flow. The exhaust after-treatment system includes at least one temperature sensor at an underbody SCR system within the exhaust after-treatment system and a DEF injector upstream of a close-coupled SCR system within the exhaust after-treatment system. The DEF injector is operated to inject DEF into the exhaust gas flow at a rate that varies as a function of a temperature measured by the temperature sensor.