A control method of an engine system is a method of controlling the engine system including an engine with a combustion chamber; a fuel injection valve configured to supply fuel to the engine; and an air-fuel ratio sensor provided in a flow path of exhaust gas from the engine. In the control method, feedback control is performed so that an air-fuel ratio in the combustion chamber becomes a target value by controlling the fuel injection valve, using an air-fuel ratio measured value obtained by the air-fuel ratio sensor. In the feedback control, a transfer function is used, the transfer function being obtained by system identification of a plant having the air-fuel ratio in the combustion chamber serve as an input and the air-fuel ratio measured value obtained by the air-fuel ratio sensor serve as an output. In the control method, a filtering process is performed to an air-fuel ratio measured value used in the feedback control, the filtering process cutting a component having a response speed faster than a delay indicated by the transfer function.

A method for operating a drive device having a drive unit producing exhaust gas and an exhaust gas posttreatment device designed as a vehicle catalytic converter for posttreatment of the exhaust gas. A first measured value describing the residual oxygen content in the exhaust gas is measured by a first lambda sensor arranged upstream of the exhaust gas posttreatment device and a second measured value describing the residual oxygen content in the exhaust gas is measured by a second lambda sensor arranged downstream of the exhaust gas posttreatment device. The combustion air ratio of a fuel-air mixture used to operate the drive unit is set during an at least temporarily performed normal operating mode on the basis of the first measured value, the second measured value, and a threshold value for the second measured value.

Methods and systems are provided for an exhaust system. In one example, a method may include determining presence of a zone flow based on a comparison of a first exhaust sensor and a second exhaust sensor. The presence or absence of the zone flow may determine a rate at which an air-fuel ratio is adjusted.

A control method of an engine system is a method of controlling the engine system including an engine with a combustion chamber; a fuel injection valve configured to supply fuel to the engine; and an air-fuel ratio sensor provided in a flow path of exhaust gas from the engine. In the control method, feedback control is performed so that an air-fuel ratio in the combustion chamber becomes a target value by controlling the fuel injection valve, using an air-fuel ratio measured value obtained by the air-fuel ratio sensor. In the feedback control, a transfer function is used, the transfer function being obtained by system identification of a plant having the air-fuel ratio in the combustion chamber serve as an input and the air-fuel ratio measured value obtained by the air-fuel ratio sensor serve as an output. In the control method, a filtering process is performed to an air-fuel ratio measured value used in the feedback control, the filtering process cutting a component having a response speed faster than a delay indicated by the transfer function.

A method for operating a drive device having a drive unit producing exhaust gas and an exhaust gas posttreatment device designed as a vehicle catalytic converter for posttreatment of the exhaust gas. A first measured value describing the residual oxygen content in the exhaust gas is measured by a first lambda sensor arranged upstream of the exhaust gas posttreatment device and a second measured value describing the residual oxygen content in the exhaust gas is measured by a second lambda sensor arranged downstream of the exhaust gas posttreatment device. The combustion air ratio of a fuel-air mixture used to operate the drive unit is set during an at least temporarily performed normal operating mode on the basis of the first measured value, the second measured value, and a threshold value for the second measured value.

Techniques are disclosed herein that provide for controlling torque in a vehicle. In some embodiments, desired torque values are generated and are compared to an amount of torque currently being generated by an engine. If a different amount of torque is desired, an engine speed target is altered in a linear fashion, and then converted back to a torque request to be provided to an engine ECU for implementation. Techniques disclosed herein may cause changes in torque demand to be limited in such a way to cause predictable and smooth changes in engine speed, even when engine speed and torque do not have a linear relationship to each other.

The invention relates to a method for exhaust gas aftertreatment in an internal combustion engine. For purposes of the exhaust gas aftertreatment in the internal combustion engine, an exhaust gas system is provided in which a first three-way catalytic converter is arranged, as seen in the direction in which the exhaust gas of the internal combustion engine flows through the exhaust gas system, while at least another three-way catalytic converter is arranged downstream from the first three-way catalytic converter. Here, at least one lambda probe is arranged in an exhaust gas channel of the exhaust gas system upstream from the appertaining three-way catalytic converters. In the proposed method, a component temperature of the three-way catalytic converters is determined and compared to a light-OFF temperature. In this process, the lambda control of the internal combustion engine is carried out by means of the lambda probe upstream from the last three-way catalytic converter that has reached its light-OFF temperature. Moreover, according to the invention, an exhaust gas aftertreatment system for carrying out such a method is being proposed.

Methods and systems are provided for catalyst control. In one example, a method may modulate a downstream catalyst by applying a square waveform to an outer feedback control loop. A fuel adjustment is performed in accordance with the square waveform to create an air-fuel ratio oscillation at an upstream catalyst brick and at a downstream catalyst brick.

A method is presented for regulating a filling of an exhaust gas component reservoir of a catalytic converter in the exhaust of an internal combustion engine. Using a first catalytic converter model, an actual fill level of the exhaust gas component reservoir is ascertained. An aging state of the catalytic converter is determined; and a set of model parameters of the first catalytic converter model is allocated to the aging state; the individual model parameters being ascertained by interpolation from basic values of model parameters, the basic values having been determined for at least two different aging states of a catalytic converter of identical design.

Methods and systems are provided for catalyst control. In one example, a method may modulate a downstream catalyst by applying a square waveform to an outer feedback control loop. A fuel adjustment is performed in accordance with the square waveform to create an air-fuel ratio oscillation at an upstream catalyst brick and at a downstream catalyst brick.