Hitachi Automotive Systems, Ltd.

Hitachi, Ltd.

Kentaro Mikawa

Naoki Okamoto

Nobuhiko Matsuo

Masahiro Arai

Ryo Miyakoshi

Takahiro Yoshino

Yuko Nagaishi, Legal Representative

The present invention has: a crank angle sensorthat outputs a crank angle signal in response to rotation of a crankshaft, the crank angle signal being preset to indicate reference positions; a cam sensorthat outputs cam signal pulses in response to rotation of an intake camshaftfor opening and closing an engine valve; an electric motorthat relatively rotates intake camshaftwith respect to crankshaft, so that electric motorcan change a rotational phase angle of intake camshaftwith respect to crankshaft; and an electronic control unitthat computes an actual rotational phase angle of intake camshaftbased on a first cam signal pulse detected after start of cranking and a first reference position of the crank signal detected thereafter, to calculate an absolute position of a variable valve timing mechanism

Control apparatus and control method for variable valve timing mechanism

A motor drive controller comprises: a driver unit comprising semiconductor switches (SW-SW) for adjusting power supplied to a motor; a control unit for outputting, to the driver unit, a control signal (PWM, PWM) for controlling on and off of the semiconductor switches (SW-SW); and an overcurrent monitoring unit for monitoring for an overcurrent at multiple locations in the driver unit. The control unit outputs, to the driver unit at a predetermined timing, the control signal for forcibly maintaining the semiconductor switches at at least two different on-off combination settings (M) one after another for a predetermine time per each on-off combination setting. Each time the predetermined time has elapsed, the control unit detects whether and which of abnormalities due to short-to-ground and short-to-supply has occurred in a motor power supply line connecting the motor to the driver unit, based on where an overcurrent is detected in the driver unit.

Motor drive controller and method for detecting abnormality in motor power supply line

In a control device and a control method for a variable valve timing mechanism according to the present invention, the rotational phase of a camshaft is measured based on the cam angle signal and crank angle signal upon receiving each pulse of the cam angle signal, and the rotational phase change over time within a period of the cam angle signal is measured based on the motor angle signal. It is decided whether the cam angle signal and/or crank angle signal has a prescribed pulse pattern at a diagnostic timing that comes after the last pulse of the cam angle signal. When this decision result is positive, it is then decided whether the motor angle sensor operates normally or abnormally based on the rotational phase and the amount of rotational phase change that are measured when the last pulse of the cam angle signal is received before the diagnostic timing.

Control device and control method for variable valve timing mechanism

It is intended to, when abnormality in either one of two rotation detection sections with different detection frequencies occurs, quickly and highly accurately detect the abnormality to favorably deal with abnormality occurring during low engine rotation. It is determined that abnormality is present in the rotation phase detection section, when an absolute value of difference between an actual VTC angle detected by a rotation phase detection section and an integrated value of a VTC change angle detected by motor rotation sensorwith the higher detection frequency than the frequency of detection of the actual VTC angle by the rotation phase detection section is equal to or greater than a predetermined value.

Device and method for detecting abnormality in rotation phase detection device, and rotation position control device using same

The present invention relates to an internal combustion engine including a VTC controller for controlling driving of a variable valve timing device and an engine control module (ECM) for calculating and transferring a valve timing control command. In the present invention, each of the VTC controller and the ECM detects whether an abnormality of a communication circuit used for transferring a control command is present or not. If the abnormality is detected, the VTC controller and the ECM set a target value for an abnormal state with the same characteristic, and perform a control operation based on the target value in the abnormal state. In this manner, a decrease in engine operability when an abnormality occurs in the communication circuit of a control command is suppressed.

Control apparatus for internal combustion engine and control method therefor

The present invention relates to a control device and a control method for a variable valve timing mechanism that changes a valve timing by adjusting a rotational speed of a motor. The control device detects a phase angle RAbased on an output of a crank angle sensor and an output of a cam angle sensor and calculates a change amount &#x394;RA of a rotational phase based on a difference between a rotation amount of a sprocket and a rotation amount of the motor. The control device stops calculating change amount &#x394;RA when a failure occurs in a motor rotation angle sensor. When a failure occurs in one of the crank angle sensor or the cam angle sensor, the control device stops calculating phase angle RAand calculates change amount &#x394;RA using a normal one of the sensors and the motor rotation angle sensor.

Control device and control method for internal combustion engine

The present invention relates to variable valve timing control device and control method, which change valve timing of an internal combustion engine. An operation amount for controlling the valve timing is computed, and an operation amount computed at position detection timing of a valve timing control system is divided and output until next position detection timing.

Variable valve timing control device for internal combustion engine, and control method

In a control apparatus for a variable valve mechanism that varies a valve characteristic of an engine valve, in a saturated state in which a calculated manipulated variable of the variable valve mechanism exceeds an outputtable manipulated variable, convergence to a desired position is achieved while suppressing a response delay and an overshoot. If a feedforward manipulated variable calculated according to a reference response exceeds an outputtable limit manipulated variable, a saturating amount (feedforward manipulated variable&#x2014;limit manipulated variable) is integrated. Upon completion of the integration, the feedforward manipulated variable is corrected based on an FF manipulated variable correction amount, and the integrated value of saturating amount is replaced by a value obtained by subtracting the FF manipulated variable correction amount each time a correction is made. When the integrated value of saturating amount reduces to a predetermined value or less, a control mode is switched to feedback control.

Control apparatus and control method for variable valve mechanism

Valve timing is held to a position close to a target value as much as possible while suppressing control errors of valve timing even though a crankshaft rotates in reverse. In an internal combustion engine which controls the valve timing by a variable valve timing mechanism (an electric VTC) driven by an electric motor, an intake valve timing is controlled after an output of an engine stop command such that: when the engine rotates in a forward direction, a real valve timing (a VTC real angle &#x3b8;r) detected by a sensor is converged to a target valve timing (a VTC target angle &#x3b8;trg) advanced for the time of start; and when the engine rotates in a reverse direction, a manipulated variable of the electric VTC is set so that the VTC real angle &#x3b8;r is held to the VTC real angle &#x3b8;r detected just before the detection of the reverse rotation.

Control device and method for controlling variable valve timing mechanism in internal combustion engine

A control unit for a variable valve timing mechanism for changing a cam phase by an actuator corrects the operation amount of the actuator immediately after an engine is started based on at least an engine rotation angle and a cam phase angle in an engine stop state.

Control unit for variable valve timing mechanism and control method for variable valve timing mechanism

A control unit for a variable valve timing mechanism for changing a cam phase by an electric actuator determines an influence on the operation of the variable valve timing mechanism based on the engine operating conditions. Then, based on the determination result, the control unit reduces the operation amount of the electric actuator in a predetermined range of the rotation angle of a camshaft.

Even when a crankshaft reversely rotates, a rotation phase of a camshaft can be accurately detected. A motor shaft rotation angle, a crankshaft forward rotation angle, a crankshaft reverse rotation angle, a final crankshaft rotation angle, a sprocket rotation angle of an electric VTC where a sprocket rotates at &#xbd; rotation speed of the crankshaft and a stator of an electric motor are integrally rotated, a motor shaft rotation angle changing amount during a control period, a sprocket rotation angle changing amount, a motor shaft rotation angle changing amount, an intake camshaft rotation angle changing amount, and a current real rotation angle of the intake camshaft are calculated sequentially, and the VTC manipulated variable is computed so that the VTC real angle follows a VTC target angle.

The application provides a control apparatus of a variable valve timing mechanism capable of converging valve timing to a target value with good responsiveness as well as with high accuracy when an engine starts. In the state where the engine starts, the variable valve timing mechanism is driven to a target value at the engine start by a second manipulated variable corresponding to a maximum variation speed of valve timing. Valve timing is estimate in the state where the variable valve timing mechanism is driven by the second manipulated variable, and when the estimated valve timing reaches the target value, a manipulated variable is switched from the second manipulated variable to a first manipulated variable which is a feedforward manipulated variable or to the first manipulated variable which is a value obtained by adding the feedforward manipulated variable and a feedback manipulated variable.

Apparatus for and method of controlling variable valve timing mechanism

In an engine provided with a valve lift amount variable mechanism and a center phase variable mechanism for an intake valve, a region between a region where a flow rate of an intake air passing through the intake valve reaches a sonic speed and a region where an intake air amount does not substantially change relative to a change in an opening area of the intake valve is made to be a learning region. Then, in order to resolve an error in intake air amount in the learning region, a correction value for correcting control process of the valve lift amount variable mechanism is learned. When the learning of the correction value is converged, the learning correction value is corrected with an occupied rate of the valve lift amount variable mechanism in the influence ratio between influences on the two mechanisms in relation to the error. Further, based on the error occurring in a state corrected with the learning correction value which is corrected with the influence ratio, a correction value for correcting control process of the center phase variable mechanism is learned.

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Isesaki, Japan

Kentaro Mikawa