Toyota Jidosha Kabushiki Kaisha

Toyota Jidosha Kogyo Kabushiki Kaisha

Tadahisa Naganawa

Senji Kato

Nobuhisa Ohkawa

Kouji Endou

Atsushi Yasumura

Shigeru Sone

Tadashi Saito

Yoshihiko Matsuda

Atsushi Gotou

Yoshihito Moriya

Hiroshi Takahashi

Kimihide Horio

Yoshiya Yamashita

Masanori Torii

Hitoshi Uda

Tsutomu Tomita

Yuji Yoshihara

Atsushi Goto

Sone Shigeru

In detecting the occurrence of an abnormality in a variable valve timing mechanism, which continuously changes a valve timing by advancing or delaying the displacement angle of an intake-side cam shaft with respect to a crankshaft, an abnormality detecting apparatus for a valve timing control apparatus determines that the variable valve timing mechanism is failing when the absolute value of the difference between a target displacement angle and a correct real displacement angle, obtained by subtracting the maximum delay-angle learning value from the real displacement angle, is greater than a first predetermined value and the absolute value of the difference between a correct real displacement angle and a previous correct real displacement angle is equal to or smaller than a second predetermined value.

Abnormality detecting apparatus for internal combustion engine

A valve timing control apparatus that continuously controls the valve timing of an intake valve or an exhaust valve of an engine. This apparatus includes a hydraulic variable valve timing mechanism, a hydraulic control valve and an electronic control unit for controlling the control valve. The variable valve timing mechanism alters the valve timing to change the valve overlap of the intake valve with respect to the exhaust valve. The hydraulic control valve controls the hydraulic pressure supplied to the variable valve timing mechanism. The real phase of the valve timing is coincided with a target phase that corresponds with the running conditions of the engine. When the real phase of the valve timing approaches the target phase, the hydraulic control valve is controlled to sustain the phase of that instant. The electronic control unit, which learns the control state of the valve-timing sustaining control, sets an initial learning value that reduces the valve overlap when the learning has started. A correction means is disallowed from computing a current specific value when the computed target value is within a predetermined range.

Valve timing control apparatus with a disallowing means

A valve timing control apparatus that continuously controls the valve timing of an intake valve or an exhaust valve of an engine. This apparatus includes a hydraulic variable valve timing mechanism, a hydraulic control valve and an electronic control unit for controlling the control valve. The variable valve timing mechanism alters the valve timing to change the valve overlap of the intake valve with respect to the exhaust valve. The hydraulic control valve controls the hydraulic pressure supplied to the variable valve timing mechanism. The real phase of the valve timing is coincided with a target phase that corresponds with the running conditions of the engine. When the real phase of the valve timing approaches the target phase, the hydraulic control valve is controlled to sustain the phase of that instant. The electronic control unit, which learns the control state of the valve-timing sustaining control, sets an initial learning value that reduces the valve overlap when the learning has started. A restricting means for restricting a correction means is included.

Valve timing control apparatus with a restricting means

A valve timing control apparatus that continuously controls the valve timing of an intake valve or an exhaust valve of an engine. This apparatus includes a hydraulic variable valve timing mechanism, a hydraulic control valve and an electronic control unit for controlling the control valve. The variable valve timing mechanism alters the valve timing to change the valve overlap of the intake valve with respect to the exhaust valve. The hydraulic control valve controls the hydraulic pressure supplied to the variable valve timing mechanism. The real phase of the valve timing is coincided with a target phase that corresponds with the running conditions of the engine. When the real phase of the valve timing approaches the target phase, the hydraulic control valve is controlled to sustain the phase of that instant. The electronic control unit, which learns the control state of the valve-timing sustaining control, sets an initial learning value that reduces the valve overlap when the learning has started. An initializing means is added for initializing a current specific value when a recondition after a malfunction is determined.

Valve timing control apparatus with an initializing means

An improvement of a valve timing control apparatus for an engine is disclosed. The apparatus has an intake valve and an exhaust valve which are alternately opened and closed in a valve timing sequence according to a rotation of a cam shaft. A timing pulley mounted on the cam shaft has a housing accommodating a plunger movable therein and a sleeve secured to the cam shaft. The housing has a first and second pressure chambers defined by the plunger and sealed with respect to each other. The plunger is arranged to move in an axial direction to selectively advance and retard the cam shaft based on differential pressure between the first pressure chamber and the second pressure chamber. A controller controls an electromagnetic valve with a specific control value to adjust the fluid pressure to be supplied to the first and second pressure chambers to maintain the valve timing sequence converged to a target valve timing. The controller corrects the specific value based on a rotational speed of the engine when the plunger is in one of the extreme positions in the chambers, and adjusts the fluid pressures based on the corrected specific value.

Valve timing control apparatus for engine

A valve timing control apparatus that continuously controls the valve timing of an intake valve or an exhaust valve of an engine. This apparatus includes a hydraulic variable valve timing mechanism, a hydraulic control valve and an electronic control unit for controlling the control valve. The variable valve timing mechanism alters the valve timing to change the valve overlap of the intake valve with respect to the exhaust valve. The hydraulic control valve controls the hydraulic pressure supplied to the variable valve timing mechanism. The real phase of the valve timing is coincided with a target phase that corresponds with the running conditions of the engine. When the real phase of the valve timing approaches the target phase, the hydraulic control valve is controlled to sustain the phase of that instant. The electronic control unit, which learns the control state of the valve-timing sustaining control, sets an initial learning value that reduces the valve overlap when the learning has started.

A cam shaft of an engine is provided with a timing change mechanism (VVT) which is driven by hydraulic pressure to alter the timing of a intake valve (valve timing). This VVT is controlled to change the valve overlap of the intake valve and an exhaust valve, thereby adjusting the suction and exhaust in and from a combustion chamber. To control the VVT, an electronic control unit (ECU) computes a target value for the valve timing in accordance with the running condition of the engine and controls the supply of the hydraulic pressure to the VVT based on the target value. The ECU determines the level of the actual hydraulic pressure given to the VVT. When the actual valve timing does not lie in a predetermined range with respect to the target value, the ECU determines that an abnormality has occurred in the VVT, and executes a predetermined fail safe routine. When the hydraulic pressure is equal to or smaller than a reference value, the ECU suppresses VVT malfunction determinations.

A cam shaft of an engine is provided with a timing change mechanism (VVT) which is driven by hydraulic pressure to alter the timing of a intake valve (valve timing). This VVT is controlled to change the valve overlap of the intake valve and an exhaust valve, thereby adjusting the suction and exhaust in and from a combustion chamber. To control the VVT, an electronic control unit (ECU) computes a target value for the valve timing in accordance with the running condition of the engine and controls the supply of the hydraulic pressure to the VVT based on the target value. The ECU determines the level of the actual hydraulic pressure given to the VVT. When the actual valve timing does not lie in a predetermined range with respect to the target value, the ECU determines that an abnormality has occurred in the VVT, and executes a predetermined fail safe routine. When the hydraulic pressure is equal to or smaller than a reference value, the ECU suppresses WT malfunction determinations.

A varying mechanism (VVT) for continuously varying the valve timing of an intake valve in a predetermined range is provided on a cam shaft in an engine. By controlling the VVT, the valve overlap period of the intake valve and an exhaust valve is continuously varied in a predetermined range, thus adjusting the amount of the internal EGR in combustion chambers. When determining that the operational load of the engine is small and intermediate based on the value of a manifold pressure, an electronic control unit (ECU) computes a target value for advancing the valve timing with respect to the rotational phase of a crankshaft based on a throttle angle, an engine speed, etc. The ECU also computes a limit value to restrict the target value in accordance with the value of the manifold pressure. When the target value is smaller than the limit value, the ECU controls the VVT based on the target value. When the target value is greater than the limit value, the ECU replaces the limit value with target value and controls the VVT based on this target value.

An exhaust gas recirculating system provided with exhaust gas recirculation interrupting means which operates to make the exhaust gas recirculation control valve interrupt recirculation of the exhaust gas when a traction control system for preventing wheel slip is operated.

Exhaust gas recirculating system

In a steady running condition of a vehicle, an air-fuel ratio is controlled to be equalized in value to a target air-fuel lener than a stoichiometric air-fuel ratio and an ignition timing is controlled to be equalized in value to a required ignition timing, so that a fuel consumption can be improved.

Method of controlling air-fuel ratio and ignition timing in internal

In a steady running condition of a vehicle, an air-fuel ratio is controlled to be equalized in value to a target air-fuel ratio leaner than a stoichiometric air-fuel ratio and an ignition timing is controlled to be equalized in value to a required ignition timing, so that a fuel consumption can be improved.

A timing adjustment mechanism in a wrapping connector driving device includes a first pulley fixedly mounted on a first revolving shaft; a second pulley fixedly mounted on a second revolving shaft, the second pulley tightly fitting on the second shaft and being seated on an end surface of the second shaft; an intermediary wrapping connector wound on the first and second pulleys and extending therebetween; an idle pulley lever swingable about the axis of rotation of the second revolving shaft; a first idle pulley disposed near the second pulley on the tension side of the intermediary wrapping connector and rotatably secured to one end of said pulley holding lever; and an idle pulley rotatably secured to the other end of said pulley holding lever near said second pulley on the slack side of said intermediary wrapping connector, wherein all of the central portions of swing of the first and second pulleys, the tension and slack side pulleys and the pulley holding lever lie in the same plane.

Timing adjustment mechanism in wrapping connector driving device

A carburetor including an inner vent communicating with an air intake of the carburetor, an outer vent communicating with an evaporated fuel gas absorbing charcoal cannister and a float chamber. The carburetor is characterized by a connecting portion for directly connecting the inner vent and the outer vent without passing through the float chamber and an opening in the connecting portion connecting the inner and outer vents to the float chamber.

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Toyota, Japan

Tadahisa Naganawa