Abstract: A control system for a throttle valve actuating device is disclosed. The throttle valve actuating device includes a throttle valve of an internal combustion engine and an actuator for actuating the throttle valve. A control object model is defined by modeling the throttle valve actuating device. The throttle valve actuating device is controlled based on a controlled object model so that an opening of said throttle valve coincides with a target opening.

Abstract: A state determining apparatus for an exhaust gas purifier is provided for accurately determining the state of the exhaust gas purifier including an adsorbent for adsorbing hydrocarbons, including a deterioration of the adsorbent, in accordance with a temperature state in an exhaust system of an internal combustion engine. The state determining apparatus for an exhaust gas purifier is arranged in an exhaust system of the internal combustion engine for determining the state of the exhaust gas purifier including the adsorbent capable of adsorbing hydrocarbons and moisture in exhaust gas.

Abstract: A temperature estimating apparatus for an internal combustion engine is provided for correctly calculating the temperature of an exhaust device even when the internal combustion engine is started under low temperature conditions. The temperature estimating apparatus comprises an ECU for estimating the temperature of a hydrocarbon adsorbent in an exhaust system of the internal combustion engine through calculations. The ECU calculates an estimated adsorbent temperature of the adsorbent in accordance with an engine rotational speed, an absolute intake pipe inner pressure, an engine water temperature, an intake temperature, and a detected humidity of exhaust gases. This calculation is started when condensation, which has occurred within an intake pipe, is eliminated.

Abstract: A control system for a throttle valve actuating device is disclosed. The throttle valve actuating device includes a throttle valve of an internal combustion engine and an actuator for actuating the throttle valve. At least one model parameter of a controlled object model which is obtained by modeling the throttle valve actuating device is calculated. A learning value of a throttle valve opening at which an actuating characteristic of the throttle valve changes, is calculated. The throttle valve actuating device is controlled using the learning value so that an opening of the throttle valve coincides with a target opening.

Abstract: A state determining apparatus for an exhaust gas purifier is provided for accurately determining the state of the exhaust gas purifier including an adsorbent for adsorbing hydrocarbons, including a deterioration of the adsorbent, in accordance with an ignition time of an internal combustion engine. The state determining apparatus for an exhaust gas purifier is arranged in an exhaust system of the internal combustion engine for determining the state of the exhaust gas purifier including the adsorbent capable of adsorbing hydrocarbons and moisture in exhaust gas. The state determining apparatus comprises a humidity sensor arranged at a location downstream of the adsorbent in the exhaust system for detecting the humidity of exhaust gases, and an ECU for determining the state of the adsorbent in accordance with the humidity of exhaust gases detected by the humidity sensor, and the ignition time of the internal combustion engine.

Abstract: A control system for a plant, having an identifier and a controller. The identifier identifies model parameters of a controlled object model which is obtained by modeling the plant. The controller calculates a control input to the plant so that an output from the plant coincides with a control target value, using the identified model parameters. The controller calculates a self-tuning control input, using the model parameters identified by the identifier. The controller further calculates a damping control input according to the rate of change in the output from the plant or the rate of change in a deviation between the output from the plant and the control target value. The controller calculates the control input to the plant as a sum of the self-tuning control input and the damping control input.

Abstract: A control system for a plant, includes a sliding mode controller for controlling the plant with a sliding mode control. The sliding mode controller controls the plant using a switching function defined as a linear function of a deviation between an output of the plant and a control target value, and changes the switching function according to at least one of a parameter indicative of the output of the plant and a parameter indicative of an amount of change in the output of the plant.

Abstract: A control system for a throttle valve actuating device is disclosed. The throttle valve actuating device includes a throttle valve of an internal combustion engine and an actuator for actuating the throttle valve. The control system includes a predictor for predicting a future throttle valve opening and controls the throttle actuating device according to the throttle valve opening predicted by the predictor so that the throttle valve opening coincides with a target opening.

Abstract: A control system for a plant which controls the plant using an identifier and a sliding mode controller. The identifier identifies a model parameter vector of a controlled object model of the plant. The sliding mode controller controls the plant using the model parameter vector identified by the identifier. According to the identifier, an identifying error of the model parameter vector is calculated and an updating vector is calculated according to the identifying error. The updating vector is corrected by multiplying a past value of at least one element of the updating vector by a predetermined value which is greater than “0” and less than “1”. The model parameter vector is calculated by adding the corrected updating vector to a reference vector of the model parameter vector.

Abstract: A manipulation variable generating unit 7 for generating a target air-fuel ratio KCMD to converge the output of an oxygen concentration sensor 5 disposed downstream of a catalytic converter 3 in an exhaust system E as a plant to a given target value has a plurality of estimators for generating data indicating estimated values of the output of the oxygen concentration sensor after a dead time of the exhaust system E or a total dead time which is the sum of the dead time of the exhaust system E and a dead time of a system comprising an engine control unit 8 and an internal combustion engine 1, according to respective different algorithms. The manipulation variable generating unit 7 generates the target air-fuel ratio KCMD according to an adaptive sliding mode control process using a value selected from the estimated values or a combined value representing a combination of the estimated values.

Abstract: The values of parameters of a model of an object exhaust system including a catalytic converter are identified from the data of outputs from an air-fuel ratio sensor and an O2 sensor which are disposed respectively upstream and downstream of the catalytic converter while an internal combustion engine associated with the catalytic converter is in operation. A deterioration evaluating parameter representing the degree of variation of time-series data of the identified parameters is determined from the time-series data of the identified parameters. The deteriorated state of the catalytic converter is evaluated based on the deterioration evaluating parameter.

Abstract: A first exhaust gas sensor 5 (air-fuel ratio sensor) and a second exhaust gas sensor 6 (O2 sensor) are disposed respectively upstream and downstream of a catalytic converter. An exhaust system E which ranges from the exhaust gas sensor 5 to the exhaust gas sensor 6 and includes the catalytic converter 3 is regarded as an object exhaust system E, and a behavior of the object exhaust system E is modeled. When an internal combustion engine 1 is in operation, parameters to be set of the model of the object exhaust system E are sequentially identified based on the data of outputs of the exhaust gas sensors 5, 6. A deteriorated state of the catalytic converter 3 is determined based on the data of the identified values.

Abstract: An exhaust emission control system for an internal combustion engine having an exhaust system is disclosed. The control system may include an exhaust gas purifying device provided in the exhaust system and an oxygen concentration sensor provided downstream of the exhaust gas purifying device. The exhaust gas purifying device may include at least an oxygen storing ability or a nitrogen oxide storing ability. An air-fuel ratio of an air-fuel mixture supplied to the engine may be enriched with respect to the stoichiometric air-fuel ratio, so as to reduce the oxygen or nitrogen oxides stored in the exhaust gas purifying device. A predicted value of the output from the oxygen concentration sensor may be calculated using a predictor based on the fuzzy logic reasoning. The completion of the reduction of the oxygen or nitrogen oxides stored in said exhaust gas purifying device may be determined according to the predicted value.

Abstract: A control system for an internal combustion engine having an exhaust system, an intake system, and an exhaust gas recirculation mechanism for recirculating exhaust gases from the exhaust system to the intake system is disclosed. The exhaust system is provided with an adsorbent for adsorbing hydrocarbon. When the adsorbent has adsorbed the hydrocarbon and the engine is operating in an idling condition, an intake air amount of the engine is increased and an ignition timing of said engine is retarded, and at the same time, the exhaust gas recirculation is performed to recirculate the hydrocarbon desorbed from the adsorbent to the intake system.

Abstract: A system for discriminating degradation of an exhaust purification system of an internal combustion engine having an adsorbent installed at a bypass exhaust gas passage branched from an exhaust pipe of the engine, which is opened by a switch-over valve at starting of the engine to introduce the exhaust gas such that the adsorbent adsorbs unburned HC in exhaust gas generated by the engine and is closed such that the adsorbent desorbs the adsorbed HC and the desorbed HC is thereafter recirculated at a position upstream of a catalyst. Based on the fact that the HC concentration rising time interval becomes short as the adsorbent degrades and adsorption capacity decrease, the time lapse since engine starting until the detected HC concentration exceeds a predetermined level is measured and is compared with a threshold value such that the adsorbent is discriminated to be degraded if the measured time lapse is less than the threshold value, thereby enabling to improve the discrimination accurately.

Abstract: There are provided a failure determination device simple in construction and capable of properly determining failure of a humidity sensor that detects the humidity of exhaust gases from an internal combustion engine and a control system for an exhaust passage changeover valve, which can switch the changeover valve with appropriate timing, thereby enabling sufficient purification of exhaust gases. In one form of the invention, an operating condition of the engine is detected. It is judged based on the detected operating condition of the engine whether or not the engine is in an operating condition in which failure determination of the humidity sensor can be executed. It is determined whether or not the humidity sensor has failed, based on a result of detection by the humidity sensor, when it has been judged that the failure determination of the humidity sensor can be executed.

Abstract: A state determining apparatus for an exhaust gas recirculation system is provided for appropriately determining the state of an exhaust gas recirculation system including an EGR passage. An exhaust gas recirculation system is arranged in an exhaust system of an internal combustion engine including an EGR passage for recirculating a portion of exhaust gases to an intake system in accordance with an operating state of the internal combustion engine. The state determining apparatus comprises a humidity sensor arranged in the EGR passage for detecting a humidity within the EGR passage, and an ECU for determining the state of the exhaust gas recirculation system based on a result detected by the humidity sensor.

Abstract: An adsorbent state determining apparatus is provided for accurately determining the state of an adsorbent including a deterioration as well as for allowing for recovery of the adsorbent if its adsorbent performance can be restored. The adsorbent state determining apparatus determines the state of an adsorbent for adsorbing hydrocarbons contained in exhaust gases. An upstream and a downstream temperature sensor are provided at upstream and downstream locations of the adsorbent in an exhaust system for detecting temperatures of exhaust gases upstream and downstream of the adsorbent. An engine water temperature sensor detects an operating state of the engine. An ECU estimates the temperature of the exhaust gas which should be detected downstream of the adsorbent during adsorption of the adsorbent based on the upstream temperature detected by the upstream temperature sensor and an engine water temperature of the engine detected by the engine water temperature sensor.

Abstract: A system for discriminating degradation of an exhaust purification system of an internal combustion engine having an adsorbent installed at a bypass exhaust gas passage branched from an exhaust pipe of the engine, which is opened by a switch-over valve at starting of the engine to introduce the exhaust gas such that the adsorbent adsorbs unburned HC in exhaust gas generated by the engine and is closed such that the adsorbent desorbs the adsorbed HC and the desorbed HC is thereafter recirculated at a position upstream of a catalyst. In the system, an inflow amount and outflow amount of HC flowing in and out of the adsorbent are determined based at least on the engine operating conditions and the detected concentration of HC. Then, the ratio therebetween is calculated and compared with a threshold value and if the ratio is less than the threshold value, the adsorbent is discriminated to be degraded, thereby enabling to improve the discrimination accurately.

Abstract: An exhaust system is regarded as being equivalent to a system for generating an output of an O2 sensor or exhaust gas sensor from a combined air-fuel ratio that is produced by combining outputs of air-fuel ratio sensors associated with respective cylinder groups according to a filtering process of the mixed model type. With the equivalent system as an object to be controlled, an exhaust system controller determines a target value for the combined air-fuel ratio, and determines a target air-fuel ratio for the cylinder groups from the target combined air-fuel ratio. The outputs of the air-fuel ratio sensors are converted to the target combined air-fuel ratio under feedback control.