Hitachi Astemo Ltd.

Hitachi Automotive Systems, Ltd.

Nobuhiko Matsuo

Hirokazu Shimizu

Kentaro Mikawa

Makoto Jitsuishi

Kenichi Machida

Naoki Okamoto

Masaki Kosuda

A control device and a control method for a variable valve timing mechanism are provided so as to improve the accuracy of cam phase angle interpolation without using a motor rotation angle sensor. The control device for the variable valve timing mechanism includes a controller configured to detect a phase angle of a cam based on a cam signal and control the phase angle of the cam by using an electric motor. The controller is configured such that a motor torque estimation unit calculates a motor torque from a motor current based on motor characteristics, a motor rotation-angle estimation unit calculates a motor rotation angle at least based on the motor torque and an engine operating state, and a conversion unit and a feedback control unit interpolate the cam phase angle of the variable valve timing mechanism from the motor rotation angle.

Control device and control method for variable valve timing mechanism

A control device for an electric variable valve timing mechanism is provided that can reduce the influence of rotation variations of an engine on a VTC detection angle computation. The control device for a variable valve timing mechanism uses a crank sensor signal and a cam sensor signal of the engine to calculate a rotation phase of the VTC mechanism. A pulse interval of the crank sensor signal is used for a calculation of the rotation phase of the VTC mechanism, and a calculation method of the rotation phase of VTC mechanism is changed depending on the pulse interval of the crank sensor signal determined before the cam sensor signal is input.

Control device for variable valve timing mechanism and control method therefor

In a variable valve control device, a variable valve control system and a method for controlling a variable valve mechanism according to the present invention, An ECM () transmits a phase detection value (RA) computed based on a crank angle signal (CRANK) and a cam angle signal (CAM) to a VTC control unit () via a communication network (), and VTC control unit () computes a phase detection value (RA) based on a motor angle signal (MAS), controls a variable valve timing mechanism () based on phase detection value (RA) in the transient state of an internal combustion engine, and controls variable valve timing mechanism () based on phase detection value (RA) in the steady state of the internal combustion engine.

Variable valve control device, variable valve control system, and method for controlling variable valve mechanism

A control device and a control method for variable valve timing mechanism according to the present invention obtains a first measurement of a rotational phase based on a rotational angle of the motor, obtains a second measurement of the rotational phase based on a relative relationship between a rotational angle of the crankshaft and a rotational angle of the camshaft, calibrates the first measurement based on the second measurement, obtains a derivative term proportional to a rate of change in a deviation between the first measurement and a target value, reduces change in derivative term when calibrating the first measurement based on the second measurement, and controls the motor based on a manipulated variable including the derivative term.

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.

An apparatus for controlling a variable valve timing mechanism includes an electronic controller which includes a microcomputer converges a valve timing of a variable valve timing mechanism to a target changing amount based on a deviation between the target changing amount and an output of a sensor for detecting a changing amount of the valve timing.

Apparatus and method for controlling 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.

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Isesaki, Japan

Nobuhiko Matsuo