Hitachi, Ltd.

Kinsaku Yamada

Mineo Kashiwaya

Hisato Tsuruta

Hiroshi Kuroiwa

Yoshishige Oyama

Yoshiyuki Tanabe

Teruo Takayama

Chiaki Niida

Toshifumi Usui

Tadao Osawa

Hiroshi Kamifuji

Tohru Nakagawa

Hirotoshi Kawano

An intake structure having a throttle body and an intake body connected to the upstream end of the throttle body and provided with a by-pass air passage for mounting an air flow meter. Locating construction is provided on the joint surfaces of the throttle body and the intake body so as to locate these bodies coaxially to each other.

Intake structure of internal combustion engine with bypass intake

An air flow meter for detecting the air flow supplied to an internal combustion engine includes a hot-wire disposed in a by-pass air passage opening at its one end to a portion of an air passage upstream from a venturi portion formed in the air passage and at its other end in the venturi portion. The by-pass air passage is provided to lengthen a distance between the inlet opening of the by-pass passage and the hot-wire, to thereby settle the flow of air in the by-pass passage at least in the area around the hot-wire. The inlet opening of the by-pass air passage may open in a plane perpendicular to the axis of the venturi portion and within the area of upper projection of the venturi portion, to prevent carbon and oil particles from coming into the by-pass passage to thereby prevent the contamination of the hot-wire.

Air flow meter assembly

In a fuel injection apparatus for internal combustion engine wherein a hot wire sensor is provided in an air bypass communicating the upstream side of a Venturi portion formed in an air-intake path with the Venturi portion, the amount of air flowing in the air bypass is controlled by an air-scaling valve driven by an electromagnetic device so that the output of the hot wire sensor converges to a set level, fuel is scaled by a fuel-scaling valve driven by the electromagnetic device in accordance with the change of the amount of air supplied to the engine, and the scaled fuel is continuously injected into the air-intake path, the set level is determined to a value which is smaller than a maximum output value of the hot wire sensor occurring when the air-scaling valve is fully opened during idling operation of the engine, thereby ensuring that the output of the hot wire sensor can converge to the set level during the idling operation.

Fuel injection apparatus for internal combustion engines

A fuel injection apparatus in accordance with the invention has a hot wire type sensor disposed in a bypass air passage and adapted to sense the flow rate of air in the bypass air passage. In order to absorb the pulsation of air flowing in the bypass air passage, the bypass air passage opens at its one end to the air cleaner of an intake system disposed in a portion upstream from the hot wire sensor. An orifice is disposed in a portion of the bypass air passage downstream from the hot wire sensor.

Fuel injection apparatus

A heat-type flow sensor is provided on the upstream side of a Venturi portion formed in an air-intake path and in an air bypass communicating with the Venturi portion. An electromagnetic device is provided to control the amount of air flowing in the air bypass so that the output of the heat-type flow sensor converges to a set level. This electromagnetic device drives a fuel-scaling valve to scale fuel in accordance with the change of the amount of air supplied to the engine, and this scaled fuel is continuously injected into the air-intake path.

An E.G.R. control system includes a pressure modulator operative to modulate the magnitude of the port vacuum as applied to a diaphragm type actuator of an E.G.R. valve. The modulator comprises a housing and a diaphragm assembly disposed in the housing and consisting of a pair of diaphragms and a member connecting the diaphragms so that they are deformed simultaneously. The diaphragm assembly divides the interior of the housing into first, second and third chambers which are communicated with the engine carburetor venturi, vented to the atmosphere and communicated with the E.G.R. passage between the E.G.R. valve and a fixed restriction in the E.G.R. passage upstream of the E.G.R. valve, respectively, so that the diaphragm assembly is moved in response to variation in the venturi vacuum and also in response to variation in the exhaust gas pressure in the E.G.R. passage between the restriction and the E.G.R. valve. A valve member is mounted on the diaphragm assembly for movement therewith to control the flow of the atmospheric air from the second chamber into the E.G.R. valve actuator so that the port vacuum as applied to the E.G.R. valve actuator is modulated. The controlled flow of the recirculated exhaust gases through the E.G.R. passage from the exhaust pipe into the intake pipe is in proportion to the intake air flow.

Exhaust gas recirculation control system

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

Kinsaku Yamada