Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
2000-03-16
2001-11-06
Moulis, Thomas N. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C123S457000
Reexamination Certificate
active
06311673
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel injection device for supplying fuel to an engine, and more particularly to an improvement in a fuel injection device including a fuel supply pipe; a fuel feed pipe communicating with a fuel pump and connected to one end portion of the fuel supply pipe; an injection pressure regulator provided at the other end portion of the fuel supply pipe, the injection pressure regulator includes a regulator housing, a diaphragm partitioning the regulator housing into a fuel chamber communicating with the fuel supply pipe and a pressure regulating chamber, pressure regulating biasing means provided in the pressure regulating chamber for biasing the diaphragm toward the fuel chamber, valve means adapted to close at a limit of displacement of the diaphragm toward the fuel chamber and to open in concert with displacement of the diaphragm from the limit toward the pressure regulating chamber, and a fuel return outlet communicating with the fuel chamber through the valve means; and a fuel injector fitted with a supply hole formed through a circumferential wall of the fuel supply pipe.
2. Description of Background Art
A fuel injection device is disclosed in Japanese Patent No. 2849800 wherein the prior art fuel injection device, a fuel supply pipe and a regulator housing of an injection pressure regulator are separate members that are joined by special connecting means. Accordingly, the number of parts is large and it is difficult to reduce the cost. Particularly in the case of a fuel injection device for a single-cylinder engine, the ratio of the cost for the injection pressure regulator and the connecting means to the cost for the whole device is large, so that cost reduction is more difficult to achieve.
SUMMARY AND OBJECTS OF THE INVENTION
It is accordingly an object of the present invention to provide a fuel injection device which can be produced with a greatly reduced number of parts to thereby achieve a cost reduction by rational integral formation of the fuel supply pipe and a part of the injection pressure regulator.
According to a first aspect of the present invention, a fuel injection device is provided that includes a fuel supply pipe; a fuel feed pipe communicating with a fuel pump and connected to one end portion of the fuel supply pipe; an injection pressure regulator provided at the other end portion of the fuel supply pipe, the injection pressure regulator includes a regulator housing, a diaphragm partitioning the regulator housing into a fuel chamber communicating with the fuel supply pipe and a pressure regulating chamber. Pressure regulating biasing means are provided in the pressure regulating chamber for biasing the diaphragm toward the fuel chamber. Valve means are adapted to close at a limit of displacement of the diaphragm toward the fuel chamber and to open in concert with displacement of the diaphragm from the limit toward the pressure regulating chamber, and a fuel return outlet communicating with the fuel chamber through the valve means. A fuel injector is fitted with a supply hole formed through a circumferential wall of the fuel supply pipe. The regulator housing is divided into a housing body defining the fuel chamber therein and a cover defining the pressure regulating chamber, and the housing body is provided that is integral with the fuel supply pipe.
With this configuration, the fuel supply pipe and the housing body are integrally formed, so that it is not necessary to provide any connecting means for connecting the fuel supply pipe and the regulator housing as in the prior art, thus greatly reducing the number of parts in the fuel injection device to thereby achieve the cost reduction.
According to a second aspect of the present invention, the valve means comprises a valve seat formed in the fuel supply pipe and a valve element attached to the diaphragm and adapted to be seated on the valve seat, and the fuel return outlet communicating with the valve seat is integral with the fuel supply pipe.
With this configuration, the fuel supply pipe and the fuel return outlet are also integrally formed, so that the number of parts can be further reduced to thereby achieve a further reduction in cost.
According to a third aspect of the present invention, there is provided in a fuel injection device including a fuel supply pipe; a fuel feed pipe communicating with a fuel pump and connected to one end portion of the fuel supply pipe and an injection pressure regulator provided at the other end portion of the fuel supply pipe. The injection pressure regulator includes a regulator housing, a diaphragm partitioning the regulator housing into a fuel chamber communicating with the fuel supply pipe and a pressure regulating chamber. A pressure regulating biasing means is provided in the pressure regulating chamber for biasing the diaphragm toward the fuel chamber. Valve means are adapted to close at a limit of displacement of the diaphragm toward the fuel chamber and to open in concert with displacement of the diaphragm from the limit toward the pressure regulating chamber, and a fuel return outlet communicating with the fuel chamber through the valve means; and a fuel injector fitted with a supply hole formed through a circumferential wall of the fuel supply pipe. The fuel supply pipe is formed from an extruded member; the regulator housing includes a housing body defining the fuel chamber therein and formed at the other end portion of the fuel supply pipe, a valve seat housing mounted in the housing body and formed from an extruded member, and a cover defining the pressure regulating chamber therein and joined to the housing body with the diaphragm held between the housing body and the cover; the valve seat housing includes a cylindrical wall fitted with an inner circumferential surface of the housing body and an arm projecting from an inner circumferential surface of the cylindrical wall to a radially central portion thereof. The valve means includes a valve seat formed on the arm so as to be exposed to the fuel chamber, and a valve element attached to the diaphragm and adapted to be seated on the valve seat. The arm is formed with a radial communication hole for communicating between the valve seat and the fuel return outlet fixed to the housing body.
With this configuration, the fuel supply pipe and the housing body are integrally formed, so that it is not necessary to provide any connecting means for connecting the fuel supply pipe and the regulator housing as in the prior art, thereby greatly reducing the number of parts in the fuel injection device to result in cost reduction. Moreover, the fuel supply pipe and the valve seat housing are formed from the respective extruded members, so that a further reduction in cost can be achieved.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
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Akamatsu Shunji
Hotta Kazuhito
Ikeda Kenichiro
Katayama Mutsumi
Birch Stewart Kolasch & Birch, LLP.
Honda Kogyo Kabushiki Kaisha
Moulis Thomas N.
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