Abstract: An example method includes interpreting an NH3 composition value at a position upstream of a selective reduction catalyst (SCR) element fluidly disposed in the exhaust conduit of an engine, interpreting a NOx composition value at a position downstream of the SCR element, and determining an NH3 sensor rationality threshold in response to the upstream NH3 composition value. The method further includes determining an NH3 sensor health value as indicating a sensor failure in response to the downstream NOx composition value exceeding the NH3 sensor rationality threshold.

Abstract: The present disclosure is directed to a system and method for controlling an energy storage device by more accurately detecting an end-of-discharge voltage of the energy storage device. More specifically, in one embodiment, the method includes determining an end-of-discharge voltage threshold for the energy storage device. Another step includes filtering the end-of-discharge voltage threshold via a filter. The method also includes adjusting a time constant of the filter based on at least one voltage-current condition. Still a further step includes comparing the filtered end-of-discharge voltage threshold and a terminal voltage of the energy storage device. Based on the comparison, the method includes determining a change of state of the energy storage device. Thus, the energy storage device can be controlled based on the change of state.

Abstract: One illustrative embodiment is a method comprising operating an engine and an aftertreatment system by controlling a plurality of charge constituents provided the engine, iteratively perturbating one or more combustion inputs effective to vary operation of the engine, and determining fuel consumption and emissions information at the operating points effective to seek a weighted optimization of multiple parameters including fuel consumption and reductant consumption while also meeting a predetermined NOx emissions criterion. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the description and figures.

Abstract: Systems and methods are provided for determining and controlling an NO2 to NOx ratio reference target in an exhaust conduit between a first SCR catalyst and a second SCR catalyst. The method includes determining a present NO2 to NOx ratio in the exhaust conduit between the first SCR catalyst and the second SCR catalyst, and providing a reductant doser command in response to a deviation of the present NO2 to NOx ratio from the NO2 to NOx ratio reference target.

Abstract: Systems and methods for managing aftertreatment systems that include passive NOx adsorption devices and SCR catalyst elements are disclosed. Temperature generation devices upstream of the passive NOx adsorption devices facilitate control of the aftertreatment systems to improve fuel economy and NOx conversion efficiency.

Abstract: A system and method are disclosed for a selective catalytic reductant (SCR) catalyst with an NH3 sensor operationally coupled mid-catalyst of the SCR catalyst and a controller in electronic communication with the NH3 sensor configured to interpret a diagnostic enablement condition of the NH3 sensor. The controller is configured to control a reductant injector to inject varying reductant amounts over a range of ANR values in response to the enablement condition being satisfied. The controller also is configured to determine a lower bound of estimates of the NH3 amount at the mid-bed catalyst position for the reductant amounts, and determine an NH3 sensor fault condition in response to actual sensor outputs and the NH3 lower bound value.

Abstract: One illustrative embodiment is a method comprising operating an engine and an aftertreatment system by controlling a plurality of charge constituents provided the engine, iteratively perturbating one or more combustion inputs effective to vary operation of the engine, and determining fuel consumption and emissions information at the operating points effective to seek a weighted optimization of multiple parameters including fuel consumption and reductant consumption while also meeting a predetermined NOx emissions criterion. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the description and figures.

Abstract: Methods and systems are disclosed for fuel drift estimation and compensation using exhaust oxygen levels and fresh air flow measurements. An actual fueling to the engine cylinders is determined from the exhaust oxygen level and fresh air flow to the internal combustion engine. The actual fueling is compared to an expected fueling based on the fueling command provided to the internal combustion engine. The difference between the actual fueling and expected fueling is fuel drift error attributed to changes or drift in the fuel injection system and is used to correct or compensate future fueling commands for the fuel drift.

Abstract: A controller system includes at least one computing device operably connected to a process having a target value for a variable parameter. The computing device(s) is configured to control the variable parameter by performing actions including: computing an error between the target value and an actual value of the variable parameter. Based on the error, the computing device(s) may calculate a desired gain adjustment of the variable parameter, and a desired mean adjustment of the variable parameter. A correction signal may be created for modifying the process by: in response to the error being positive, creating the correction signal by adding the desired mean adjustment and the desired gain adjustment, and in response to the error being negative, creating the correction signal by differencing the desired mean adjustment and the desired gain adjustment. A related program product may carry out similar functions.

Abstract: A cooling fluid flow control system for a turbine section of a steam turbine system and a related program product are provided. In one embodiment, a system includes at least one computing device operably connected to a cooling system. The computing device may be configured to control a flow rate of cooling fluid supplied to a steam turbine system by the cooling system by performing actions including modeling a sensitivity of a wheel space temperature to a change in the flow rate in the form of a piecewise linear relationship, the piecewise linear relationship including a flooded flow rate above which the wheel space temperature becomes insensitive to increased flow rate. The computing device also periodically modifies the flow rate of the cooling fluid supplied to the wheel space of the turbine section to approximate a minimum flooded flow rate based on the measured flow rate and the modeling.

Abstract: A system includes an engine, an exhaust conduit for the engine, a first SCR catalyst fluidly coupled to the exhaust conduit, and a second SCR catalyst fluidly coupled to the exhaust conduit at a position downstream of the first SCR catalyst. The system further includes an ammonia sensor positioned between the first and second SCR catalysts. A reductant doser is positioned upstream of the first SCR catalyst. The system includes a controller that determines an amount of NH3 present from the NH3 sensor, and computes an actuator response function from at least one operating condition of the first SCR catalyst. The actuator response function includes a reductant injector response as a function of the amount of NH3, and the actuator response function includes a response discontinuity. The controller further determines a reductant injection amount from the amount of NH3 and the actuator response function, and provides a reductant injector command.

Abstract: An example method includes interpreting an NH3 composition value at a position upstream of a selective reduction catalyst (SCR) element fluidly disposed in the exhaust conduit of an engine, interpreting a NOx composition value at a position downstream of the SCR element, and determining an NH3 sensor rationality threshold in response to the upstream NH3 composition value. The method further includes determining an NH3 sensor health value as indicating a sensor failure in response to the downstream NOx composition value exceeding the NH3 sensor rationality threshold.

Abstract: A method includes determining whether selective catalytic reduction (SCR) test conditions are present, and in response to the SCR test conditions being present, operating an SCR aftertreatment system at a number of reduced ammonia to NOx ratio (ANR) operating points. The method further includes determining a deNOx efficiency value corresponding to each of the ANR operating points. The method further includes determining a reductant correction value in response to the deNOx efficiency values corresponding to each of the ANR operating points, and providing a reductant injection command in response to the reductant correction value.

Abstract: Systems and method are disclosed in which a portion of an exhaust gas stream is received into an exhaust outlet flow path downstream of a first selective catalytic reduction (SCR) catalyst and upstream of a second SCR catalyst. The removed portion is treated with a diagnostic SCR catalyst element and an NH3 concentration composition of the treated removed portion is determined. The NH3 concentration is used to control injection of reductant upstream of the first SCR catalyst.

Abstract: A method includes determining a current mid-bed NH3 amount by operating an NH3 sensor positioned at a mid-bed location for an engine aftertreatment system having two SCR catalyst beds. The method further includes operating a NOx sensor positioned at the mid-bed location, and interpreting a current mid-bed ammonia to NOx ratio (ANR) and a current mid-bed NOx in response to the mid-bed NH3 amount and the operating the NOx sensor. The method further includes correcting an output value of the NOx sensor for cross-sensitivity to NH3. The method includes determining a mid-bed ANR constraint, determining a feedforward mid-bed NOx target, and providing a reductant injector command in response to the current mid-bed ANR, the current mid-bed NOx, the ANR constraint, and the feedforward mid-bed NOx target.

Abstract: A method includes providing: a selective catalytic reduction (SCR) catalyst disposed in an exhaust gas stream of an internal combustion engine, a reagent injector operationally coupled to the exhaust gas stream at a position upstream of the SCR catalyst, and a NOx sensor coupled to the exhaust gas stream at a position downstream of at least a first portion of the SCR catalyst. The method includes operating an extremum seeking controller to determine a first reagent injection amount corresponding to a predetermined slope of ?NOx/?ANR, the ?NOx/?ANR determined according to the NOx sensor, providing a reagent injection command in response to the first reagent injection amount, and injecting an amount of the reagent in response to the reagent injection command.

Abstract: A method includes providing: a selective catalytic reduction (SCR) catalyst disposed in an exhaust gas stream of an internal combustion engine, a reagent injector operationally coupled to the exhaust gas stream at a position upstream of the SCR catalyst, and a NOx sensor coupled to the exhaust gas stream at a position downstream of at least a first portion of the SCR catalyst. The method includes operating an extremum seeking controller to determine a first reagent injection amount corresponding to a predetermined slope of ?NOx/?ANR, the ?NOx/?ANR determined according to the NOx sensor, providing a reagent injection command in response to the first reagent injection amount, and injecting an amount of the reagent in response to the reagent injection command.

Abstract: A system includes an internal combustion engine, an exhaust conduit fluidly coupled to the internal combustion engine and an SCR catalyst, and a reductant doser operationally coupled to the exhaust conduit at a position upstream of the SCR catalyst. The reductant doser is responsive to a reductant doser command. The system includes a controller having a number of modules functionally structured to execute operations to compensate for transient operation of the system. An NH3 target module interprets a reductant amount target that is a target amount of reductant in the exhaust conduit at a position upstream of the SCR catalyst. A transient adjustment module detects a transient event in the SCR catalyst and provides an adjusted reductant amount target in response to the transient event and the reductant amount target. A dosing control module provides the reductant doser command in response to the adjusted reductant amount target.

Abstract: A method for controlling charge flow in an internal combustion engine includes operating an engine having a VGT. The method includes determining a target and current charge flow and EGR flow. The method further includes determining an error term for the charge flow and the EGR flow, and determining an exhaust pressure feedback command in response to the error terms. The exhaust pressure feedback command is combined with an exhaust pressure feedforward command, and the VGT is controlled in response to the exhaust pressure feedback command. The method additionally includes determining the exhaust pressure feedback command in response to a current EGR valve position. The method further includes controlling an EGR flow rate with the EGR valve at relatively closed EGR valve positions, and controlling the EGR flow rate with exhaust pressure at relatively open EGR valve positions.

Abstract: Systems and methods are disclosed that include an exhaust gas stream produced by an engine and an aftertreatment system including an SCR catalyst element receiving at least a portion of the exhaust gas stream. An exhaust outlet flow path has an inlet fluidly coupled to the exhaust gas stream at a position downstream of at least a portion of the SCR catalyst element that bypasses at least a portion of exhaust gas stream to provide for compositional measurement of the exhaust gas with a compositional sensor located downstream of a diagnostic catalyst positioned in the exhaust outlet flow path.