Hitachi, Ltd.

Hitachi Automotive Engineering Co., Ltd.

Hitachi Automotive Engineering, Ltd.

Chiaki Niida

Tomoo Ito

Kinsaku Yamada

Koichiro Yamada

Teruo Takayama

Tsutomu Okazaki

Hiroaki Saeki

Torazo Nishimiya

Hiroshi Kamifuji

Yuki Ejiri

Tomo Ito

Hideki Honma

Masamitsu Asakura

Takashi Iseyama

A fluid control valve which regulates a flow rate of a liquid and, more particularly, which controls a fluid by axially moving a valve body fixed to a valve shaft. The fluid control valve comprises a device for absorbing vibrations of the valve shaft in a direction perpendicular to the axis thereof. More specifically, there is provided a device for exerting a pressing force to lightly press the valve shaft against the inner walls of bearings. Alternatively, the valve shaft may be held between a plurality of elastic plates fixed on the inner surface of a valve casing. A support member for such a valve shaft used in the fluid control valve comprises a disk having a center hole through which the valve shaft is inserted, an annular member formed around the disk, and an elastic piece one end of which is secured to the disk or the annular member, while the other end of the elastic piece is extended to the vicinity of the center of the hole, so that the annular member is fixed on the inner surface of the valve casing, and that the distal end of the elastic piece is pressed against the valve shaft which is extended through the hole. According to the invention, vibrations of the center shaft in radial directions can be suppressed to prevent unstable movements of the valve.

Fluid control valve, valve support member therefor and idling air amount

Automotive engine idle speed control device meters the flow rate of air supplied to the engine bypassing an intake pipe thereof during engine idle operation to thereby control the engine idle speed. An actuating vacuum is produced in accordance with an electrical signal and acts on a diaphragm fixed to a valve movable with the diaphragm to meter the bypass air flow. To cancel any external force acting on the valve, adjusting means is provided to control the vacuum on the diaphragm independently of the electrical signal to displace the diaphragm in a direction opposite to the direction of action of the external force on the valve.

Automotive engine idle speed control device

In a rotational speed control apparatus for an internal combustion engine in which a signal-responsive diaphragm, whose controlling position is determined by a controlled negative pressure signal, is provided with a valve member controlling to negative pressure acting upon a driving diaphragm controlling the opening of a throttle valve, the negative pressure acting upon the driving diaphragm, when the controlled negative pressure signal is detected to be not normal, is controlled to be shifted to the level at which the driving diaphragm is rendered substantially non-operable.

Rotational speed control apparatus for internal combustion engines

A suction pipe is provided to suck and introduce air from its one end and is connected at its other end to an internal combustion engine. The suction pipe is provided at its one end with a venturi portion and a throttle valve. A first negative pressure detector is provided to detect the negative pressure at the portion of the suction pipe remote from the internal combustion engine, so as to sense a comparatively gentle pressure rise in the suction pipe. A control valve is provided to be opened and closed in accordance with the output from the first negative pressure detector, thereby to control the flow rate of air supplied into the suction pipe. A second negative pressure detector is provided to detect the negative pressure at a portion of the suction pipe remote from the internal combustion engine, so as to sense an abrupt increase of the negative pressure in the suction pipe. This second negative pressure detector is disposed between the first valve and the first negative pressure detector and adapted to produce an output in accordance with which the first valve is controlled.

Device for controlling negative pressure in suction pipe of internal

An exhaust-gas recirculation (EGR) system for an internal-combustion engine comprises an EGR valve for controlling the amount of exhaust-gas recirculation installed midway in an EGR passage that establishes communication between the intake and exhaust pipes of the engine, and an exhaust-gas transducer valve for opening and closing by the exhaust pressure of the exhaust gas an atmospheric-releasing orifice formed midway in a vacuum conduit for introducing vacuum into the EGR valve. An acceleration control unit is connected to the exhaust-pressure transducer valve to prevent the entry of air from the atmospheric-releasing orifice into the vacuum conduit in the early stage of engine acceleration, even while the transducer valve is in operation, so as to control the generation of nitrous oxides during the acceleration.

Exhaust-gas recirculation system

A control valve of an exhaust recirculation apparatus comprises an expansible vacuum chamber communicating with a venturi portion and having a first diaphragm and a spring urging the diaphragm to expand the chamber, an expansible exhaust pressure chamber having a second diaphragm disposed to oppose the first diaphragm at a distance and communicating with an exhaust inflow chamber, a control chamber disposed between the above chambers and defined by the first and second diaphragms and a frame mounting the first and second diaphragms thereon. The first and second diaphragms are connected by a bracket to which a seal member is secured through a block. In the control chamber is disposed a conduit one end of which has an opening facing the seal member with a gap therebetween, the other end communicates with a throttle portion and an exhaust gas recirculation valve provided in an exhaust recirculation passage. Upon increase of vacuum at the venturi portion, the diaphragms are moved to cause the seal member to approach and seal the opening in the conduit, whereby vacuum in the conduit is increased to open the exhaust recirculation of the exhaust gas, exhaust pressure in the exhaust inflow chamber is decreased to move the diaphragms so as to separate the seal member from the opening, so that the vacuum in the conduit will be decreased a little for the exhaust recirculation valve to be held at a suitable opening.

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Katsuta, Japan

Chiaki Niida