Hitachi, Ltd.

Shoji Shimo

Takeshi Atago

Yukio Hosho

Hisanori Moriya

Hideo Usui

Satosi Suzuki

A variable stage type carburetor provided with a venturi vane which is adapted to vary the venturi area in a venturi portion thereof, commensurate to the opening of a throttle valve. This carburetor features that, in the running condition where the opening of a throttle valve is considerably large and yet the quantity of intake air is relatively less, the venturi vane is forcedly displaced in a direction to be closed so as to increase the venturi negative pressure in the venturi portion, thereby enhancing the injection of fuel.

Variable stage type carburetor

An intake system adapted to be used in combination with an internal combustion engine having a main combustion chamber and a preliminary or subcombustion chamber equipped with an ignition plug. There is provided an intake cylinder having a venturi portion which allows the passing of the total amount of air being fed to both combustion chambers and a throttle valve controlling the amount of air being fed to respective combustion chambers. The intake cylinder is divided into a main intake passage and sub-intake passage, both of which lead to both combustion chambers, respectively. A metering orifice is provided in the sub-intake passage, so that a ratio in amount, of air passing through respective intake passages may be maintained at a given value. In respective intake passages, there are provided fuel discharge values, to which are connected fuel passages leading from a single fuel pressure controlling valve for use in providing fuel pressure commensurate with the negative pressure in the venturi portion. By the provision of the metering orifices in respective fuel passages, a ratio in flow rate, of fuel being introduced to respective fuel discharge valves is maintained at a given value. Thus, there is provided an intake system in which a ratio in flow rate, of mixture charges being fed to the main combustion chamber and the sub-combustion chamber, as well as a ratio in air-fuel-ratio, of mixture charges being fed thereto are maintained constant.

Intake system in internal combustion engine

A secondary air flow rate control device for use in an exhaust gas purifying device of the type in which the secondary air delivered from an air pump is fed through an air passage to an exhaust gas purifying device provided in an exhaust system for purifying the unburnt components contained in exhaust gases from an internal combustion engine, while an aperture for bleeding air to atmosphere is provided in the aforesaid air passage, with a valve being provided in the aforesaid aperture, so that at the time of acceleration of an engine, the aforesaid valve is closed to increase the amount of the secondary air to be fed to the exhaust gas purifying device. This secondary air flow rate control device includes an air flow rate control mechanism for driving the valve which is provided in the aforesaid aperture for bleeding air to atmosphere, and an acceleration detecting mechanism for detecting the accelerating condition of an engine according to the pressure in a suction pipe, the aforesaid acceleration detecting mechanism being integral with the aforesaid air flow rate control mechanism, whereby by directly driving the aforesaid air flow rate control mechanism by using a pressure detected by means of the aforesaid acceleration detecting mechanism, the aforesaid aperture open to atmosphere is closed at the time of acceleration of an engine to thereby increase the amount of the secondary air to be fed to the exhaust gas purifying device, thus improving the responsive characteristics of the air flow rate control mechanism, with the additional advantages of achievement of compactness and simplicity for the construction of the air flow rate control device.

Secondary air flow rate control device for use in exhaust gas purifying

A secondary air control device which comprises an air passage communicating an air pump with a recombustion device and having a resistor such as an orifice provided midway of the passage and a control valve for maintaining substantially constant the pressure ratio of the pressure on the upstream side of the aforesaid resistor to that on the downstream side thereof, said control valve being so designed as to be operated in association with the pressure of the secondary air and that of exhaust gas, thereby eliminating fluctuation in pressure in the secondary air due to reduction in the discharging performance of the air pump, and thus the secondary air proportional in quantity to the exhaust gas from an engine may be supplied.

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Katsuta, Japan

Shoji Shimo