Unisia Jecs Corporation

Hitachi Unisia Automotive, Ltd.

Unista Jecs Corporation

Hidekazu Yoshizawa

Hajime Hosoya

Satoru Watanabe

Koji Takahashi

Shigeo Ohkuma

Norio Moteki

Haruhiro Iwaki

The present invention has an object to provide an air-fuel ratio control apparatus of an internal combustion engine and a method thereof, for estimating with high accuracy an oxygen adsorption amount in an exhaust purification catalyst, and controlling the oxygen adsorption amount in the exhaust purification catalyst at an optimum amount, thereby enabling to maintain high exhaust purification efficiency. To this end, in the present invention, there is stored a catalyst model that receives an oxygen amount which is not used for the oxidization/reduction in an exhaust purification catalyst disposed on an exhaust passage of an engine, and outputs an oxygen concentration in an exhaust gas downstream of the exhaust purification catalyst, the oxygen amount which is not used for the oxidization/reduction in the exhaust purification catalyst is calculated based on the oxygen concentration in the exhaust gas upstream of the exhaust purification catalyst and an engine intake air amount, parameters of the catalyst model are sequentially estimated based on the calculated oxygen amount and the oxygen concentration in the exhaust gas downstream of the exhaust purification catalyst, an oxygen adsorption amount in the exhaust purification catalyst is calculated using the estimated parameters of the catalyst model, thereby feedback controlling an air-fuel ratio upstream of the exhaust purification catalyst so that the calculated oxygen adsorption amount reaches an optimum oxygen adsorption amount.

Air-fuel ratio control apparatus of internal combustion engine and method thereof

The present invention is constituted so that an actual air-fuel ratio is detected by an air-fuel ratio sensor, a plant model representing a plant between a fuel injection valve and the air-fuel ratio sensor is sequentially identified to calculate parameters of the plant model, a control gain for calculating a feedback control amount is calculated using the calculated parameters, and the feedback control amount is calculated using the calculated control gain, wherein an absolute value of an input side parameter set on an input side of the plant model is limited to be a predetermined limit value or above, among the calculated parameters.

An air-fuel ratio detected by an air-fuel ratio sensor is estimated based on an estimation value of air-fuel ratio of an air-fuel mixture formed inside a cylinder, and based on an air-fuel ratio estimated as being detected by this air-fuel ratio sensor and the air-fuel ratio detected based on an output signal of the air-fuel ratio sensor, the estimation value of the cylinder air-fuel ratio is corrected and a fuel injection quantity is corrected based on the corrected cylinder air-fuel ratio.

Method and device for feedback controlling air-fuel ratio of internal combustion engine

In a valve timing control apparatus for an internal combustion engine to control a rotation phase of a camshaft relative to a crankshaft so that opening and closing timing of intake and exhaust valves is variably controlled, a feedback correction amount of the rotation phase is calculated by a sliding mode control using a switching function obtained by adding a deviation between a target value and an actual value to a differential value of the deviation, to thereby feedback control using the feedback correction amount. According to this constitution, a control can be executed with high robust and with low influence due to disturbances.

Apparatus and method of valve timing control for internal combustion engine

In an air-fuel ratio feedback control of an internal combustion engine aimed to approximate an air-fuel ratio to a target air-fuel ratio set according to operating conditions of the engine, the feedback control is carried out using the feedback control amount which is computed according to a sliding mode control, having a deviation between the target air-fuel ratio and the detected air-fuel ratio detected by the air-fuel ratio sensor set as a switching function. According to the present invention, a simple air-fuel ratio feedback control is carried out according to an accurate sliding mode control with no dispersion for each engine, that is easy to design, and that can be applied generally to any kind of vehicle or engine. Further, by varying the feedback gain depending on operating conditions, by controlling the computing cycle of the feedback control amount, or by performing a Smith dead time compensation control, the influence provided by the dead time element existing in the control object is eliminated, thereby ensuring the response characteristic and stability of the control system.

Air-fuel ratio control device for internal combustion engine and method thereof

In a sliding mode control for restraining an air-fuel ratio state on a switching line set on a phase plane shown by a deviation between an actual air-fuel ratio and a target air fuel ratio, and a differential value of the deviation, an inclination of the switching line is made small, when the smaller an intake air quantity is, the longer a detection delay time of the air-fuel ratio is.

Air-fuel ratio feedback control apparatus of internal combustion engine and method thereof

In a valve timing control apparatus for an internal combustion engine using an oil pressure control, a feedback correction amount is calculated so as to have a linear term proportional to a deviation between a target value and an actual value of the valve timing control apparatus, and a non-linear term using a switching function by a sliding mode control. Further, a dither control is added to the feedback correction amount and a learning is performed for a basic control amount and a control gain. Therefore, a control can be executed with high robust, high accuracy and quick response.

Apparatus and a method for sliding mode control

A valve timing control apparatus in an internal combustion engine is feedback controlled by a sliding mode control and an abnormality of the sliding mode control is diagnosed. During a slight abnormality other than a crucial abnormality which makes the feedback control impossible, the system is feedback controlled to converge to a target value using only a non-linear term calculated by the sliding mode control.

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Atsugi, Japan

Hidekazu Yoshizawa