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.

A method for regulation of an internal combustion engine with an SCR catalytic converter in which the operating point of the engine is predefined by an engine control unit and the operating point of the catalytic converter is predefined by an SCR control unit. An overall system quality measure is calculated by an optimizer in accordance with fed back values of the engine control unit and fed back values of the SCR control unit, by changing the default values for the engine control unit and the SCR control unit, the optimizer minimizes the overall system quality measure for a prediction horizon regarding operating costs. On the basis of the minimized overall system quality measure the optimizer sets the default values for the engine control unit and the default values for the SCR control unit as decisive for setting the operating point of the engine and the catalytic converter.

A control system for a vehicle, the control system having one or more controllers, the control system being arranged to: determine a likelihood of a NOx adsorber trap of a vehicle requiring purging; determine an efficiency of purging the NOx adsorber trap; determine an operating efficiency of a selective catalyst reduction system of the vehicle; determine a schedule for purging of the NOx adsorber trap of the vehicle in dependence on the likelihood of the NOx adsorber trap requiring purging, the efficiency of purging the NOx adsorber trap, and the operating efficiency of the selective catalyst reduction system; and control purging of the NOx adsorber trap according to the schedule.

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.

An engine system including a fuel system control arrangement includes an internal combustion engine including an exhaust line, one or more cylinders, and one or more fuel injectors corresponding to the one or more cylinders, means for determining fresh air mass flow into an intake to the engine, a nitrogen oxide (NOx) sensor in the exhaust line, and a controller configured to determine oxygen (O2) in exhaust gas based on a signal from the NOx sensor and to calculate a current fuel injection quantity based on the O2 in the exhaust gas and determined fresh air mass flow into the intake, to compare the current fuel injection quantity to a theoretical fuel injection quantity under current operating conditions, and to adjust an amount of fuel injection from the one or more fuel injectors when the current fuel injection quantity differs from the theoretical fuel injection quantity to make the current fuel injection quantity closer to the theoretical fuel injection quantity.

An internal combustion engine with an open-loop or closed-loop control device (2), wherein at least one combustion chamber (3) of the internal combustion engine (1) is designed to burn a fuel-air mixture using at least one combustion parameters that can be influenced by the open-loop or closed-loop control device (2), wherein the open-loop or closed-loop control device (2) has an emission control loop that is configured to actuate the at least one actuator that influences the at least one combustion parameter as a substitute parameter for NOx emissions by means of a functional relationship in such way that at last one combustion parameter can be set for each target or actual power rating of the internal combustion engine (1), wherein the functional relationship takes account of an influence of a change of the exhaust backpressure (p.sub.3’) affecting at least one combustion chamber (3).

An internal combustion engine with an open-loop or closed-loop control device (2), wherein at least one combustion chamber (3) of the internal combustion engine (1) is designed to burn a fuel-air mixture using at least one combustion parameters that can be influenced by the open-loop or closed-loop control device (2), wherein the open-loop or closed-loop control device (2) has an emission control loop that is configured to actuate the at least one actuator that influences the at least one combustion parameter as a substitute parameter for NOx emissions by means of a functional relationship in such way that at last one combustion parameter can be set for each target or actual power rating of the internal combustion engine (1), wherein the functional relationship takes account of an influence of a change of the exhaust backpressure (p.sub.3′) affecting at least one combustion chamber (3).

Methods and systems are provided for increasing EGR delivered to an engine. In one example, a method may include determining an EVO timing set point and an external EGR setpoint in parallel, based on an inverse model. The EVO timing may be adjusted based on a combination of the EVO timing setpoint and an EGR cylinder balancing feedback loop, thereby varying internal EGR to the engine to supplement external EGR.

An engine system includes an engine with an intake manifold and an exhaust manifold, a turbocharger including a turbine in communication with the exhaust manifold and a compressor in communication with the intake manifold, and a regulator configured to control a flow of exhaust gas through the turbine. A controller of the engine system is operably connected with the regulator and is configured to monitor an engine load and an exhaust gas temperature during operation of the engine, identify a proscribed engine NOx emissions level based on the engine load and the exhaust gas temperature and, when the proscribed engine NOx emissions level is identified, modify the flow of exhaust gas through the turbine to reduce the energy extracted from the exhaust gas by the turbine and reduce a drive power provided to the compressor, thereby reducing a flow of intake air provided to the intake manifold by the compressor.

A system, apparatus, and method for controlling an engine system can provide fuel reactivity compensation control for an engine of the engine system. Pilot fuel quantity supplied to the engine can be controlled using a nitrous oxide (NOx) error. Likewise, air-to-fuel ratio (AFR) for the engine can be controlled using the NOx error. Each of a pilot fuel offset and an AFR control trim can be generated using the NOx error. The pilot fuel offset and the AFR control trim can be used to control the pilot fuel quantity and the AFR, respectively.