Gas and liquid contact apparatus – Fluid distribution – Pumping
Reexamination Certificate
1999-07-27
2001-04-17
Chiesa, Richard L. (Department: 1724)
Gas and liquid contact apparatus
Fluid distribution
Pumping
C261S035000, C261S069200, C261SDIG006, C261SDIG008
Reexamination Certificate
active
06217008
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a diaphragm-type carburetor, and in particular, to an improvement in a diaphragm-type carburetor including a constant-pressure fuel chamber having an outlet bore communicating with a lower end of a fuel nozzle through a fuel jet and a check valve, a fuel pump incorporated in a fuel passage which communicates between an inlet bore in the constant-pressure fuel chamber and a fuel tank for providing fuel for the constant-pressure fuel chamber in response to a pulsation pressure in a pulsation pressure generating source, and a fuel introduction control valve for controlling the introduction of the fuel into the constant-pressure fuel chamber by opening or closing the inlet bore in the constant-pressure fuel chamber. The fuel introduction control valve is provided with a cylindrical valve seat member mounted on an upper wall of the constant-pressure fuel chamber and having the inlet bore in its upper end, and a valve member lifted and lowered within the valve seat member to open and close the inlet bore.
2. Description of the Related Art
A diaphragm-type carburetor is already known, as disclosed, for example, in Japanese Patent Application Laid-Open No. 1-151758.
In such a carburetor, fuel delivered to a constant-pressure fuel chamber by operation of a diaphragm pump is often converted into a large amount of fuel vapor by a pressure pulsation received from the diaphragm pump, heat or vibration received from an engine or the like. When a large amount of fuel vapor is introduced all at one time into the constant-pressure fuel chamber and ejected from the fuel nozzle, the fuel-air ratio of the fuel-air mixture is extremely reduced, thereby causing misoperation of the engine.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a diaphragm-type carburetor of the above-described type, wherein when fuel vapor is generated in the fuel discharged from the diaphragm pump, a large amount of fuel vapor can be prevented from being ejected all at one time from the fuel nozzle by finely dividing the fuel vapor and introducing it along with the fuel, thereby substantially suppressing the variation in fuel-air ratio of a fuel-air mixture.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided a diaphragm-type carburetor comprising a constant-pressure fuel chamber having an outlet bore communicating with a lower end of a fuel nozzle through a fuel jet and a check valve, a fuel pump incorporated in a fuel passage for permitting communication between an inlet bore in the constant-pressure fuel chamber and a fuel tank. The pump pumps fuel into the constant-pressure fuel chamber in response to a pulsation pressure in a pulsation pressure generating source, and a fuel introduction control valve for controlling the introduction of the fuel into the constant-pressure fuel chamber by opening and closing the inlet bore in the constant-pressure fuel chamber. The fuel introduction control valve has a cylindrical valve seat member mounted on an upper wall of the constant-pressure fuel chamber and has the inlet bore at the upper end thereof. A valve member is raised and lowered within the valve seat member to open and close the inlet bore, wherein a fuel vapor treating chamber is provided in the fuel passages for finely dividing fuel vapor at a location before the inlet bore.
With the above arrangement, when fuel vapor is generated in the fuel discharged from the fuel pump, the fuel vapor is finely divided in the fuel vapor treating chamber and passes through the inlet bore in the valve seat member along with the fuel into the constant-pressure fuel chamber. Therefore, the finely divided fuel vapor passes smoothly into the fuel nozzle along with the fuel without stagnating in the constant-pressure fuel chamber. Thus, the amount of fuel vapor ejected from the fuel nozzle per unit time is relatively small, whereby the reduction in fuel-air ratio of a fuel-air mixture can be suppressed to a small level to ensure the normal operation of the engine.
According to a second aspect and feature of the present invention, a porous element having a large number of pores is placed in the fuel vapor treating chamber.
With the above arrangement, the fuel vapor can be finely divided by a simple structure, wherein the porous element is placed in the fuel vapor treating chamber, and thus, it is possible to provide a diaphragm-type carburetor at a lower cost.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3765657 (1973-10-01), Du Bois
patent: 3825237 (1974-07-01), Aoyama et al.
patent: 4003968 (1977-01-01), Rickert
patent: 4271093 (1981-06-01), Kobayashi
patent: 5441673 (1995-08-01), Gerhardy
patent: 5599484 (1997-02-01), Tobinai
patent: 5676887 (1997-10-01), Soeda et al.
patent: 5681508 (1997-10-01), Gerhardy
patent: 1-151758 (1989-06-01), None
Abe Hitoshi
Ishikawa Hirohisa
Kamiya Naoyuki
Arent Fox Kintner Plotkin & Kahn
Chiesa Richard L.
Honda Giken Kogyo Kabushiki Kaisha
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