Methods and systems are provided for identifying degraded exhaust gas temperature (EGT) sensor responses. In one example, a method may include cycling an engine between a higher temperature operating mode and a lower temperature operating mode while maintaining engine torque output across the higher temperature operating mode and the lower temperature operating modes, both the higher temperature operating mode and the lower temperature operating mode providing stoichiometric exhaust gas to a downstream catalyst, and characterizing a response behavior of an EGT sensor based on output of the EGT sensor during the cycling. In this way, stepwise exhaust gas temperature changes are produced for characterizing the EGT sensor response without disrupting emissions and torque control.

The disclosed embodiments relate to a method and to a device for controlling an internal combustion engine supercharged by an exhaust-gas turbocharger. The method includes: determining the time duration required for a specific internal combustion engine in operation, at a current operating point and with a predefined combination of settings of switching actuators, to perform an increase of the charge pressure from a current charge pressure to a target charge pressure associated with a target operating point; comparing the determined time duration with a multiplicity of stored time durations, which are each assigned to a predefined different combination of the settings of the switching actuators; and controlling the internal combustion engine with that combination of the settings of the switching actuators which permits the quickest increase of the charge pressure to the target charge pressure.

An estimation method to determine the concentration of recirculated exhaust gas present in a cylinder of an internal combustion engine; the concentrations of recirculated exhaust gas in a gas mixture flowing through an intake duct are periodically stored in a buffer; a first instant is determined, in which a programming of a following combustion in the cylinder is carried out; an advance time is determined, which elapses between the first instant and a second instant in the future, in which air will be taken into the cylinder for the following combustion in the cylinder; a transport time is determined; a third instant in the past is determined by subtracting from the first instant an amount of time which is equal to the difference between the transport time and the advance time; and the concentration of recirculated exhaust gas present in the cylinder in the second instant is estimated depending on a concentration of recirculated exhaust gas contained in the buffer (30) and corresponding to the third instant.

A purge control method of the present disclosure includes determining whether or not a vehicle quickly decelerates in a driving situation in which a large amount of fuel evaporation gas is discharged, decreasing purge duty for operating a purge control solenoid valve when the controller determines that the vehicle is in a state of quick deceleration, and decreasing a purge flow of the fuel evaporation gas by controlling operation of the purge control solenoid valve by the purge duty.

In an internal combustion engine which performs a homogeneous lean combustion mode and a stratified lean combustion mode, there is provided a new internal combustion engine control device capable of obtaining a stable combustion state by decreasing influences of delay of an air flow and a degree of change of a transient state and smoothly performing switching between the homogeneous lean combustion mode and the stratified lean combustion mode. Accordingly, in the present invention, when switching between the stratified lean mode in which a compression stroke injection is performed by a direct injection injector 7 and the homogeneous lean combustion mode in which an intake stroke injection is performed by the direct injection injector 7 is performed, a predetermined delay time t is provided from at least a switching operation of a tumble control valve 6, a switching operation between the compression stroke injection and the intake stroke injection is performed, and the delay time t is set so as to correspond to a magnitude of the degree of change L of the transient state. A switching timing between the compression stroke injection and the intake stroke injection is controlled according to the flow delay of an air control system such as the tumble control valve 6 and the degree of change L of the transient state, and thus, it is possible to improve combustion stability in a combustion chamber.

A system for control of an internal combustion system having subsystems, each with different response times. Subsystems may include a fuel system, an air handling system, and an aftertreatment system, each being operated in response to a set of reference values generated by a respective target determiner. Calibration of each subsystem may be performed independently. The fuel system is controlled at a first time constant. The air handling system is controlled on the order of a second time constant slower than the first time constant. The aftertreatment system is controlled on the order of a third time constant slower than the second time constant. A subsystem manager is optionally in operative communication with each target determiner to coordinate control. Generally, dynamic parameters from slower subsystems are treated as static parameters when determining reference values for controlling a faster subsystem.

A method of two-step variable valve lift (VVL) malfunction avoidance learning control may include: in a two-step VVL system which is operated with a main lift and a secondary lift, verifying, by an electronic control unit (ECU), an operation avoidance area based on locking of a lock pin of a cam follower ; performing VVL operation learning, in which a failure of occurrence of the second lift is determined on the basis of a locking failure of the cam follower due to an initially set value of the operation avoidance area; and reflecting the operation avoidance area to the two-step VVL system with a corrected set value which is obtained through the VVL operation learning.

A hybrid vehicle has an engine (E) that is capable of changing a combustion mode between a stoichiometric combustion mode and a lean combustion mode and a motor/generator (MG) that is capable of performing torque assist by a power running operation and torque absorption by a regenerative operation. As a boundary between a stoichiometric combustion operating region and a lean combustion operating region, a second boundary (L2) at a torque decrease has a hysteresis at a low torque side with respect to a first boundary (L1) at a torque increase. Upon shift from the stoichiometric combustion operating region to the lean combustion operating region, for delay in increase of an intake-air quantity, decrease in fuel and the torque assist by the motor/generator (MG) are carried out, and an exhaust air-fuel ratio is changed stepwise.

An object is to reduce the influence of a hydrogen-ascribable difference between the measurement value of an oxygen sensor and the actual value. An exhaust system includes an oxygen sensor configured to measure the air-fuel ratio of exhaust gas provided in an exhaust passage of an internal combustion engine and including a diffusion rate limiting layer and a controller configured to correct the measurement value of the oxygen sensor in such a way as to increase the measurement value of the oxygen sensor by an amount of correction that is made larger when the responsivity of the oxygen sensor to changes in the air-fuel ratio of the internal combustion engine is high than when it is low in the same operation state of the internal combustion engine.

A control system is provided for controlling an internal combustion engine. The internal combustion engine includes a turbocharging unit and an exhaust gas recirculation assembly. The control system is adapted to issue a boost pressure control signal. The control system includes a boost pressure controller adapted to determine the boost pressure control signal. The boost pressure controller has a first response time. The control system is adapted to issue an exhaust gas recirculation control signal for controlling an amount of recirculated exhaust gas via the exhaust gas recirculation assembly. The control system includes an exhaust gas recirculation controller adapted to determine the exhaust gas recirculation control signal independently of the boost pressure control signal. The exhaust gas recirculation controller has a second response time, wherein the first response time differs from the second response time.