Abstract: An exhaust gas purifying apparatus for an internal combustion engine is provided for simultaneously realizing sufficient recovery of the adsorbing capability of an adsorbent and limitation to an increase in exhaust resistance. The exhaust gas purifying apparatus for an internal combustion engine comprises a flow path switching valve for switching an exhaust gas flow path to a bypass exhaust passage or to a main exhaust passage, three-way catalysts, and an HC adsorbent arranged in the bypass exhaust passage for adsorbing hydrocarbons in exhaust gases and fully desorbing the adsorbed hydrocarbons when it is heated to a full desorption temperature or higher. A troidal passage of the main exhaust passage completely surrounds a portion of the bypass exhaust passage in which the HC adsorbent is arranged. A ratio S1/S2 of the cross-sectional area S2 of the troidal passage to the cross-sectional area of a flow-in passage is set in a range from 1.

Abstract: In an internal combustion engine having a double-structure exhaust passage comprised of an inner (bypass) exhaust passage and an outer (main) exhaust passage arranged to surround the outside of the inner exhaust passage such that exhaust gases are discharged through one of the inner and outer exhaust passages, an exhaust gas characteristic detecting apparatus is capable of reliably detecting the characteristic of exhaust gases through the inner exhaust passage. The detecting apparatus comprises a guide pipe extending across the outer exhaust passage and having an exhaust gas introducing port facing the inner exhaust passage for introducing exhaust gases flowing into the inner exhaust passage into the guide pipe, and a sensor having a sensing unit for detecting the humidity of exhaust gases and arranged such that the sensing unit is positioned in the guide pipe.

Abstract: An object system is regarded as being equivalent to a system for generating an output of an O2 sensor or exhaust gas sensor from a target combined air-fuel ratio that is produced by combining target air-fuel ratios KCMD for respective cylinder groups according to a filtering process of the mixed model type. With the equivalent system as an object to be controlled, an air-fuel ratio processing controller determines a target combined air-fuel ratio, and determines a target air-fuel ratio KCMD for each of the cylinder groups from the target combined air-fuel ratio. The air-fuel ratios in the cylinder groups are manipulated into the target air-fuel ratio according to a feed-forward control process.

Abstract: A control system for an internal combustion engine having a catalyst arranged in the exhaust system is disclosed. In the control system, catalyst temperature rise accelerating control is executed by increasing the intake air amount immediately after starting of the engine and retarding the ignition timing to make the rotational speed of the engine coincide with a target rotational speed. The air-fuel ratio of an air-fuel mixture supplied to the engine is controlled to a lean region with respect to the stoichiometric ratio immediately after starting of the engine. The degree of making the air-fuel ratio leaner is suppressed when the retard amount of the ignition timing during the execution of the catalyst temperature rise accelerating control is less than a predetermined retard amount.

Abstract: A first cutoff valve 24 and a second cutoff valve 41 are closed in a state in which an internal combustion engine 1 is stopped, and a reducing amount of a pressure P0 in a high pressure passageway 11 after the passage of a predetermined decision time T0 and a reducing amount of a pressure P2 in a low pressure passageway 12 after the passage of a predetermined decision time T2 are measured. When the reducing amount of the first pressure P0 is equal to or larger than a predetermined reducing amount &Dgr;P0, it is decided that a leakage is generated in the high pressure passageway 11. When the reducing amount of the second pressure P2 is equal to or larger than a predetermined reducing amount &Dgr;P2, it is decided that a leakage is generated in the low pressure passageway 12.

Abstract: A catalyst state detector for detecting a state of an exhaust gas purifying catalyst which is capable of accurately detecting the state, including deterioration, of an HC adsorbent contained in the exhaust gas purifying catalyst for adsorbing hydrocarbons in exhaust gases of an internal combustion engine, and can be manufactured at a low cost. The exhaust gas purifying catalyst is arranged at an intermediate portion of an exhaust pipe, and the HC adsorbent is capable of adsorbing hydrocarbons and moisture in exhaust gases. The catalyst state detector comprises a downstream humidity sensor arranged at a location downstream of the HC adsorbent in the exhaust pipe for detecting a humidity of the exhaust gases, and an adsorbent state detecting unit (ECU) for detecting the state of the HC adsorbent in accordance with the result of detection made by the downstream humidity sensor.

Abstract: An allowable range (adaptive allowable range) for limiting a manipulated variable generated in order to converge the difference between an output from an O2 sensor disposed downstream of a catalytic converter and a target value thereof to “0” is sequentially updated depending on how the manipulated variable deviates from the allowable range.

Abstract: While the amount of intake air introduced into an internal combustion engine is being increased by an intake air quantity control unit, an ignition timing control unit manipulates the ignition timing of the internal combustion engine to converge the rotational speed of the internal combustion engine to a target rotational speed according to a feedback control process (PI control process). The ignition timing control unit has a function to vary the feedback gain of the feedback control process depending on the ignition timing, such that the feedback gain is smaller as the ignition timing being manipulated is more retarded.

Abstract: A plant control system has a reference value setting unit for variably setting a reference value for an air-fuel ratio to be given to an exhaust system including a catalytic converter, depending on a component based on an adaptive control law of a manipulated variable of the air-fuel ratio generated by a controller according to an adaptive sliding mode control process in order to converge an output of an O2 sensor disposed downstream of the catalytic converter to a target value. The plant control system also has an estimator for estimating the difference between an output of the O2 sensor after the dead time of the exhaust system and a target value therefor, using the difference between the set reference value and a detected value of the air-fuel ratio, and giving the estimated difference to the controller.

Abstract: A plant control system has a reference value setting unit for variably setting a reference value for an air-fuel ratio to be given to an exhaust system including a catalytic converter, depending on a component based on an adaptive control law of a manipulated variable of the air-fuel ratio generated by a controller according to an adaptive sliding mode control process in order to converge an output of an O2 sensor disposed downstream of the catalytic converter to a target value. The manipulated variable generated by the controller represents the difference between the air-fuel ratio and the reference value, required to converge the output of the O2 sensor to the target value.

Abstract: An object system for generating an output signal of an O2 sensor from a target air-fuel ratio is expressed as a model including a response delay element and a dead time element. Data of identified values of parameters of the model are sequentially generated by an identifier. Data of an estimated value of the output signal of the O2 sensor after a dead time of the object system is sequentially generated by an estimator. The target air-fuel ratio is generated according to an adaptive sliding mode control process performed by a sliding mode controller using the data of the identified and estimated values. The air-fuel ratio of an internal combustion engine is manipulated on the basis of the target air-fuel ratio according to a feed-forward control process.

Abstract: An apparatus for controlling an internal combustion engine has an amount-of-intake-air control unit for generating a command value for the opening of a flow control valve in an intake passage of the engine, which emits exhaust gases through a catalytic converter, so as to increase an amount of intake air introduced into a combustion chamber by a predetermined quantity greater when the engine operates in an idling mode after it has started to operate than when the engine operates in a normal idling mode, and controlling the opening of the flow control valve based on the generated command value, and an ignition timing control unit for controlling the ignition timing according to a feedback control process to correct the ignition timing so as to be retarded in order to converge the rotational speed of the engine to a predetermined target rotational speed while the amount of intake air is being increased.

Abstract: A plant control system has an actuator for generating an input to the plant, a first sensor for detecting an output from the plant, a manipulated variable determining unit for sequentially determining a manipulated variable which determines the input to the plant to equalize the output from the first sensor to a predetermined target value, an actuator controller for controlling operation of the actuator based on the manipulated variable determined by the manipulated variable determining unit, and an estimator for sequentially generating data representing an estimated value of the output from the first sensor after a total dead time which is the sum of a first dead time of the plant and a second dead time of a system which comprises the actuator and the actuator controller. The manipulated variable determining unit determines the manipulated variable based on the data generated by the estimator.

Abstract: A control system for a plant includes a sensor for detecting an output from the plant, an adaptive controller for controlling a manipulated variable applied to control of the plant in such a manner that an output from the sensor becomes equal to a desired value, and an adaptive parameter-adjusting device for adjusting adaptive parameters used by the adaptive controller. The adaptive parameter-adjusting device has an identification error-calculating device for calculating an identification error of the adaptive parameters and generating an identification error signal indicative of the calculated identification error, and an adjusting device for adjusting the adaptive parameters based on the calculated identification error. The adaptive parameter-adjusting device includes a non-linear filter for generating an output of 0 or approximately 0 in response to the identification error signal when the identification error is within a predetermined range.

Abstract: A control system for controlling an internal combustion engine which discharge exhaust gases through an emission purifier includes a controller which increases the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling after the internal combustion engine has started to operate, to a level which is greater by a predetermined increase than the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling normally. The controller also generates a command value for ignition timing of the internal combustion engine according to a feedback control process to converge the rotational speed of the internal combustion engine toward a predetermined target rotational speed, and controlling the ignition timing of the internal combustion engine based on the generated command value thereby to retard the ignition timing.

Abstract: A plant control system controls a plant modeled as a discrete-system model including an element relative to a response delay of the plant. The plant control system includes an actuator for generating an input to the plant, a first detector detecting an output from the plant, and a second detector for detecting the input to the plant which is generated by the actuator. An identifier identifies parameters to be established of the discrete-system model based on data representing an output of the first detector and data representing an output of the second detector. A manipulated variable determining unit determines a manipulated variable which determines the input to the plant to control operation of the actuator such that the output from the first detector will be equalized to a predetermined target value, according to a predetermining algorithm using the parameters of the discrete-system model which are identified by the identifier.

Abstract: A plant control system for controlling a plant includes an actuator for generating an input to the plant and a first detector for detecting an output from the plant. A manipulated variable determining unit determines a manipulated variable which determines the input to the plant according to a sliding mode control process such that an output from the first detector will be equalized to a predetermined target value. The manipulated variable determining unit determines the manipulated variable to converge a plurality of state quantities, which comprise differences between a plurality of present and previous time-series data of the output of the first detector and the target value, onto a balanced point on a hyperplane for the sliding mode control process, which is defined by a linear function having variables represented respectively by the state quantities.

Abstract: A plant control system controls a plant modeled as a discrete-system model including an element relative to a response delay of the plant and an element relative to a dead time of the plant. The plant control system includes an actuator for generating an input to the plant, a first detector for detecting an output from the plant, and a second detector for detecting the input to the plant. An estimator generates data representing an estimated value of an output of the first detector after the dead time, based on data representing the output of the first detector and data representing an output of the second detector. A manipulated variable determining unit determines a manipulated variable which determines the input to the plant, based on the estimated value, represented by the data generated by the estimator, of the output of the first detector after the dead time.

Abstract: A system for controlling an air/fuel ratio of an internal combustion engine, including a feedback control loop having an adaptive controller (STR controller) that receives as inputs a desired value r and a controlled variable y output from the plant (engine) and an adaptation mechanism that estimates adaptive parameters. The STR controller calculates a feedback correction coefficient KSTR, as an output u based upon at least the adaptive parameters, for correcting a basic amount of fuel supply calculated by retrieving mapped data, prepared beforehand, such that the controlled variable y converges to the desired value r. The system is configured such that the controlled variable y is determined based upon the detected air/fuel ratio KACT and a desired air/fuel ratio KCMD so that the desired value r is a predetermined value. More specifically, the controlled variable is determined to be a ratio between the detected air/fuel ratio and the desired air/fuel ratio such that the desired value r is 1.0 or thereabout.

Abstract: A fuel metering control system for an internal combustion engine including a feedback loop having an adaptive controller and an adaptation mechanism that estimates controller parameters .theta.. The adaptive controller corrects the quantity of fuel injection to bring a controlled variable obtained at least based on an output of said air/fuel ratio sensor, to a desired value. The adaptation mechanism is input with the controlled variable once per prescribed crank angle such as a TDC of a certain cylinder and estimates the controller parameters. Using the controller parameters, it is discriminated whether system operates stably.