Methods and systems are provided for catalyst control. In one example, a method may include controlling an air-fuel ratio downstream of a catalyst by adjusting fuel injection. The fuel injection is adjusted based on control parameters updated online through system identification at a point of feedback control instability.

An internal combustion engine includes an air charging system with a boost air system. A method to control the boost air in the air charging system, decoupled from the air and EGR system controls, includes monitoring a reference boost pressure and operating parameters of the air charging system; creating a turbocharger energy balance model of the air charging system; applying feedback linearization control to the turbocharger energy balance model to create an approximately linearized feedback system; and determining a boost control command for the air charging system using the approximately linearized feedback system based on the monitored reference boost pressure and the monitored operating parameters of the air charging system. The boost air in the air charging system is controlled based upon the boost control command.

A method of controlling a Free Piston Mover, the method comprising the steps of: generating a Control Parameter Set for closed loop control of a Target Control Variable, this set comprising a Target Control Variable Function together with one or more of: a Stroke Threshold Function; a Feed Forward Current Function; a Feedback Terms Function; Control Parameter Set Transition Conditions; transmitting the Control Parameter Set to an In-Stroke Controller in advance of the start of a Stroke to be controlled; modifying one or more of the constituents of the Control Parameter Set for any Future Stroke of the Free Piston Mover using a Future-Stroke Controller; and transmitting the modified Control Parameter Set to the In-Stroke Controller for the control of any Future Stroke.

A control apparatus 57 is a 2-input, 2-output integral-type optimal servo system in which intake air amount and intake oxygen concentration are used as control quantities (y1, y2) and the degree of opening of a control valve of an exhaust gas recirculation apparatus and the degree of opening of a control valve of a supercharger equipped with a variable flow rate mechanism are used as manipulated quantities (u1, u2), and includes an output feedback system. The control apparatus (57) is provided with an EGR valve opening degree unit (70) and an opening rate valve of the supercharger. Each of the control units includes a non-interference controller (64) for eliminating interference between the manipulated quantity for the control valve of the exhaust gas recirculation apparatus and the manipulated quantity for the control valve of the supercharger equipped with the variable flow rate mechanism.

Methods and systems are provided for identifying and rejecting asymmetric faults that cause engine emissions to be biased rich or lean. In one example, a method for an engine system comprises generating a UEGO sensor feedback set-point adjustment based on slower and faster time components within an outer loop of a catalyst control system; generating an inner-loop bias-offset correction from the slower time component; and indicating degradation of the engine system based on a comparison of the bias-offset correction to a degradation threshold. In this way, the total outer-loop control authority is increased while maintaining drivability and noise, vibration, and harshness (NVH) constraints and meeting emission standards in the presence of an air-to-fuel ratio biasing fault.

A system for controlling an air/fuel ratio in an engine based on catalyst deactivation includes an NH.sub.3 detector disposed downstream from the three way catalyst, and a subsystem that compares measured values of NH.sub.3 concentration with a nominal value of NH.sub.3 concentration at rich operating conditions. A subsystem adjusts the air/fuel ratio based on the measured value of NH.sub.3 concentration and estimated CO concentration.

A control method for a fuel injection valve for an internal combustion engine is disclosed, wherein at least one control signal for actuating a drive of the injection valve is generated in recurring injection cycles and as a function of a target stroke height of a closing element of the injection valve, wherein the drive is actuated by the control signal to lift the closing element to the target stroke height and the closing element is lifted to an actual stroke height by means of the drive, wherein at least one measured parameter correlated with the actual stroke height is captured and the actual stroke height is determined as a function of said at least one measured parameter, wherein the control signal is generated in at least one of the subsequent injection cycles as a function of a deviation of the actual stroke height from the target stroke height.

Various approaches are described for air-fuel ratio control in an engine. In one example, a method include adjusting fuel injection from an anticipatory controller responsive to exhaust oxygen feedback of an exhaust gas sensor positioned upstream of an exhaust catalyst, the anticipatory controller including a first integral term and a second integral term, the second integral term correcting for past fuel disturbances. In this way, it is possible to provide fast responses to errors via the anticipatory controller, while corrected known past fueling errors, on average, via the second integral term.

Controlling turbocharger boost pressure using exhaust pressure estimated from engine cylinder pressure.

Internal combustion engine with an intake for intaking air and/or an air-fuel-mixture, at least one compressor for compressing a gas flow, an electric machine for driving the at least one compressor, at least one control valve, and a controller for controlling the electric machine and the at least one control valve, wherein the at least one compressor and the at least one control valve are configured to directly or indirectly influence a mass flow and/or an intake pressure in the intake, wherein the controller is configured to control the electric machine in dependence on at least one command value for the at least one control valve.