Abstract: In a sliding mode control system to feedback control a control object amount to a target value by calculating an operation amount based on a non-linear term calculated corresponding to a switching function and a linear term, an abnormality judgment signal is output when an operation amount by the non-linear term does not change within a predetermined time from when a predetermined period of time has elapsed after the target value has changed.

Abstract: A device according to the present invention is provided with element temperature measurement voltage application circuit for temporarily applying a predetermined voltage for element temperature measurement to a sensor element of an air-fuel ratio sensor equipped to an exhaust system of an internal combustion engine, first sensor output reading circuit for reading in a sensor output just before applied with the voltage, and second sensor output reading circuit for reading in a sensor output being applied with the voltage, wherein the element temperature of the air-fuel ratio sensor is estimated based on the sensor output just before applied with the voltage and the sensor output being applied with the voltage. Further, during internal resistance measurement of the sensor element of the air-fuel ratio sensor equipped to the exhaust system of the internal combustion engine, a voltage applied to the heater for heating the sensor element is maintained to be constant.

Abstract: 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.

Abstract: In a variable valve timing apparatus for variably controlling the valve timing by changing a rotation phase of a camshaft with respect to a crankshaft, an abnormality diagnosis of the apparatus is performed on a condition that a change amount per unit time in a control target value of the rotation phase has been kept equal to or less than a predetermined limit value for a predetermined period or more.

Abstract: In a variable valve timing mechanism that changes a rotation phase of a camshaft with respect to a crankshaft by a braking force of an electromagnetic brake to vary valve timing of engine valves, a controlled variable of the electromagnetic brake is corrected according to an engine rotation speed and a valve lift amount, that are correlative to an input torque from a camshaft side to the variable valve timing mechanism.

Abstract: 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.

Abstract: The present invention is constituted so that an actual air-fuel ratio is detected by an exhaust state by an air-fuel ratio sensor, parameters of transfer functions are calculated while sequentially identifying a plant model representing a plant between a fuel injection valve and the air-fuel ratio sensor by the transfer functions, a feedback control amount of said air-fuel ratio control signal is set using the parameters of the identified pant model, an offset correction amount of the air-fuel ratio control signal is set, and the plant model is identified using a valve obtained by adding the offset correction amount to the feedback control amount, and the actual air-fuel ratio.

Abstract: 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.

Abstract: A combustion state during the initial stage after ignition is detected, and based on the detected combustion state, it is judged whether or not incomplete combustion has occurred, and when it is judged that incomplete combustion has occurred, an ignition signal is output so as to perform the re-ignition immediately.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: In a variable valve timing apparatus for variably controlling the valve timing by changing a rotation phase of a camshaft with respect to a crankshaft, an abnormality diagnosis of the apparatus is performed on a condition that a change amount per unit time in a control target value of the rotation phase has been kept equal to or less than a predetermined limit value for a predetermined period or more.

Abstract: A device according to the present invention is provided with element temperature measurement voltage application circuit for temporarily applying a predetermined voltage for element temperature measurement to a sensor element of an air-fuel ratio sensor equipped to an exhaust system of an internal combustion engine, first sensor output reading circuit for reading in a sensor output just before applied with the voltage, and second sensor output reading circuit for reading in a sensor output being applied with the voltage, wherein the element temperature of the air-fuel ratio sensor is estimated based on the sensor output just before applied with the voltage and the sensor output being applied with the voltage. Further, during internal resistance measurement of the sensor element of the air-fuel ratio sensor equipped to the exhaust system of the internal combustion engine, a voltage applied to the heater for heating the sensor element is maintained to be constant.

Abstract: 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.

Abstract: 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.

Abstract: With an electronically controlled throttle type internal combustion engine, where a target opening of a throttle valve is set according to a required output of the engine, and the throttle valve is opened and closed with an actuator so as to obtain a target opening; air quantity learning for learning and correcting the target opening of the throttle valve so as to obtain a target intake air quantity is performed by comparing an intake air quantity estimated based on a detection value of the throttle valve opening and an actually detected intake air quantity, at the time of idling the engine. After completion of the air quantity learning, friction learning for learning and correcting the target opening of the throttle valve so as to obtain a target engine output is performed while feedback controlling the throttle valve opening so that the engine rotation speed approaches a target idle rotation speed, at the time of idling the engine.

Abstract: Discrimination is effected as to which of low-pressure and high-pressure conditions the pressure of fuel to be fed to a fuel injection valve is in. If in the low-pressure condition, the fuel injection pulse widths are corrected by assuming that the fuel pressure is a predetermined reference pressure, since the detection errors of a fuel pressure sensor are large. If in the high-pressure condition, the fuel injection pulse widths are corrected based on an actual fuel pressure detected by the fuel pressure sensor.

Abstract: In the control method and apparatus of a direct injection gasoline engine, as for the uniform charge combustion mode performing only the intake stroke injection and the stratified charge combustion mode performing only the compression stroke injection, the injection timing is determined by referring to the injection timing map set for each mode. On the other hand, in the double injection mode performing the intake stroke injection and the compression stroke injection, the injection timing map for the intake stroke injection and the injection timing map for the compression stroke injection are both equipped, and the injection timing in the intake stroke injection is determined by the fuel quantity being injected by the intake stroke, and the injection timing in the compression stroke injection is determined by the fuel quantity being injected by the compression stroke.

Abstract: In a direct injection type gasoline engine for directly injecting fuel into each cylinder, fuel pressures supplied to each fuel injection valve are detected, and the fuel injection pulse width is detected according to the detected fuel pressures. Here, the fuel injection pulse width is corrected based on a value obtained by smoothing the detected values of the fuel pressures and at the same time, a smoothing level is changed according to the transitional or steady state of the engine, thereby achieving the response characteristic of correction at the transitional state and the stable correction at the steady state.