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: 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: 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: A system and method are provided for estimating an instantaneous EGR mass flow rate corresponding to a flow rate of exhaust gas through an exhaust gas recirculation (EGR) conduit fluidly coupled between an exhaust manifold and an intake manifold of an internal combustion engine with an EGR cooler positioned in-line with the EGR conduit. An operating position of the engine is monitored, and the instantaneous EGR mass flow rate is estimated at each of a plurality of fixed increments of the engine position based on EGR cooler outlet temperature, intake manifold pressure and a pressure differential across a flow restriction disposed in-line with the exhaust gas conduit between the EGR cooler and the intake manifold.

Abstract: A method is disclosed for adjusting a target EGR mass flow in response to a current charge flow and target EGR fraction. The method includes interpreting an air-fuel ratio and a target air-fuel ratio. The method further includes interpreting a charge flow and a target EGR fraction. The method further includes determining an adjusted target EGR mass flow based on the air-fuel ratio, the target air-fuel ratio, the charge flow, and the target EGR fraction. The method further includes controlling an actuator based on the adjusted target EGR mass flow.

Abstract: One embodiment is a method including operating an SCR system at a plurality of commanded ammonia to NOx input ratios, providing a plurality of data indicating NOx output from the SCR system for the plurality of commanded ammonia to NOx input ratios, and evaluating the plurality of data to diagnose the SCR system. Additional embodiment are methods, systems, and apparatuses including SCR diagnostics. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

Abstract: A rigid metal housing is positioned downstream of a coating applicator. The housing supports a plurality of positionable contact elements formed of a low friction, high wear-resistant material, which extend inwardly from the housing to engage a slow speed rotating rod. At least one of the contact elements is adjustable to support the rod for stable rotation, and to retain an effective seal between the contact elements and the rod to thereby prevent leakage of clearing/lubricating fluid into the applied coating. The contact elements may be advanced inwardly as the elements and the rod wear, thereby extending the effective life of the rod holder apparatus. Screws may bear against a rear contact element through segmented backing plates allowing refinement of the coat weight along the width of the substrate. Furthermore, an air tube may be positioned between the housing and a rear fixture to adjust overall coating thickness.