Title of Invention

"VAPOR GAS SEPARATION DEVICE"

Abstract

To provide a vapor gas separation device and a strainer which are capable of efficiently separating vapor gas from feed fuel without requiring a power source which generates suction force and an electric power source therefor. [Constitution] A strainer 120 is mainly composed of: an inlet 301 through which feed fuel flows in from a fuel tank; a filter chamber 303 in which a filter 302 to filter feed fuel is housed; a vapor reservoir 304 provided on top of the filter chamber 303; an outlet 305 through which filtered feed fuel is supplied to a fuel pump; an inlet 306 through which return fuel applied with pressure flows in; a return fuel passage 307 through which return fuel is force-fed; an outlet 308 through which return fuel is discharged; and a vapor gas suction path 310 which communicates with the vapor reservoir 304 and the return fuel passage 307.

Full Text

The present invention relates to a vapor gas separation device and a strainer, and particularly to a vapor gas separation device and a strainer which are capable of efficiently separating vapor gas from feed fuel to be supplied to a fuel pump. [Prior Art] A fuel supply system according to a fuel injection device of a vehicle mounted with an internal combustion engine is structured such that fuel in a fuel tank is supplied to the engine through a feed pipe by a fuel pump, and excessive fuel is sent back to the fuel tank through a return pipe. In this fuel sent back through the return pipe to the fuel tank, vapor (air bubbles) generated due to overheating of the fuel by the engine is sometimes contained. Moreover, vapor gas may enter the fuel when pressure is reduced due to fuel suction from the fuel tank or under a high temperature. Vapor gas which has not been discharged and thus remained stays inside the feed pipe or the return pipe and prevents smooth supply of the fuel, thereby causing hard starting of the engine. Moreover, efficiency of the fuel pump is reduced if vapor gas is supplied to the fuel pump. Further, accuracy in measurement of the fuel is deteriorated, and therefore, the fuel is not . supplied to an injector with a specific amount. In order t9 solve such technical problems, in Japanese Unexamined Utility Model Application No. Sho 62(1987}-162388 , as shown in Fig. 8, disclosed is a technology of separating vapor gas V from feed fuel by: forming a suction port and an air vent on a filter chamber provided on the suctioning side of a fuel pump; connecting a feed pipe communicating with a fuel tank to the suction port; and connecting a gas vent pipe communicating with a vapor phase portion of the fuel tank to the air vent. Moreover, in Japanese Unexamined Utility Model Application No. Sho 61 ( 1986) -32567, as shown in Fig. 9, disclosed is a technology which has enabled efficient separation of vapor gas from fuel by providing a fuel reservoir above a fuel pump and under a level of oil in a fuel tank. [Problems to be Solved by the Invention] Both of the above-described conventional vapor gas separation devices only separate vapor gas which has naturally ascended out from feed fuel due to ascending force of itself, and means for proactively allowing vapor gas to ascend is 'not implemented. Therefore, when an internal pressure of the fuel tank is increased, vapor gas cannot be separated efficiently. In contrast, vapor gas contained in fuel can be more efficiently separated by allowing suction force to act on the fuel than by separating by means of its natural ascending force. However, in order to generate suction force, a drive source such as .suction pump and an electric power source therefor are required. Therefore, there has been a technical problem that an increase in weight is caused. An object of the present invention is to provide a vapor gas separation device and a strainer which are capable of solving all the foregoing problems in the conventional technologies, and of efficiently separating vapor gas from feed fuel without requiring a power source for generating suction force and an electric power source therefor. [Means for Solving the Problems] In order to achieve the above object, a vapor gas separation device of the present invention is characterized in that the following means is implemented therein. (1) The vapor gas separation device is characterized by including: a vapor reservoir provided on top of a communicating passage which communicates with the inlet and the outlet for feed fuel; a return fuel passage which discharges, from one end thereof, return fuel force-fed from the other end; and a vapor gas suction path of which one end is open to the return fuel passage and the other end is open to the vapor reservoir. (2) The vapor gas separation device is characterized in that the return fuel passage includes a jet valve, and one end of the vapor gas suction path is open on a downstream side of the jet valve. Further, the strainer of the present invention is characterized in that the following means is implemented therein . (3) The strainer is characterized by including: a filter chamber which communicates with the inlet and the outlet for feed fuel and includes a vapor reservoir on top thereof; a filter installed in the filter chamber; a return fuel passage which discharges, from one end thereof, return fuel force-fed from the other end; and a vapor gas suction path of which one end is open to the return fuel passage and the other end is open to the vapor reservoir. (4) The strainer is characterized in that the return fuel passage includes a jet valve, and one end of the vapor gas suction path is open on a downstream side of the jet valve. According to the above-described characteristic (1), when return fuel is flowed through the return fuel passage, suction force is generated in vapor gas suction path due to an injector effect, thereby developing a negative pressure in the vapor reservoir. Consequently, vapor gas collected in the vapor reservoir is forcibly discharged together with the return fuel. In addition, suction force acts on feed fuel in the communicating passag'e, and accordingly, ascending of vapor gas from feed fuel is accelerated, whereby efficient separation of vapor gas can be achieved. According to the above-described characteristic (2), a flow rate of return fuel flowing through the return fuel passage can be accelerated, which results in increased suction force generated in the vapor gas suction path. Therefore, more efficient separation can be achieved. According to the above-described characteristic (3), when return fuel is flowed through the return fuel passage, suction force is generated in vapor gas suction path due to an injector effect, thereby developing a negative pressure in the vapor reservoir. Consequently, vapor gas collected in the vapor reservoir is forcibly discharged together with the return fuel. In addition, suction force acts on feed fuel in the filter chamber, and accordingly, ascending of vapor gas from feed fuel is accelerated, whereby efficient separation of vapor gas can be achieved. According to the above-described characteristic (4), a flow rate of return fuel flowing through the return fuel passage can be accelerated, which results in increased suction force generated in the vapor gas suction path. Therefore, more efficient separation can be achieved. The present invention relates to a vapor gas separation device having an inlet and an outlet for feed fuel which separates vapor gas from the feed fuel flowed in from the inlet and discharges the vapor gas, characterized by comprising: a vapor reservoir provided on top of a communicating passage which communicates with the inlet and the outlet; a return fuel passage which discharges, from one end thereof, return fuel force-fed from the other end; and a vapor gas suction path of which one end is open to the return fuel passage and the other end is open to the vapor reservoir. The present invention also relates to a strainer having an inlet and an outlet for feed fuel which filters the feed fuel flowed in from the inlet and discharges the feed fuel from the outlet, characterized by comprising: a filter chamber which communicates with the inlet and the outlet and includes a vapor reservoir on top thereof; a filter installed in the filter chamber; a return fuel passage which discharges, from one end thereof, return fuel force-fed from the other end; and a vapor gas suction path of which one end is open to the return fuel passage and the other end is open to the vapor reservoir. [MODES FOR CARRYING OUT THE INVENTION] Hereinbelow, preferred embodiments of the present invention will be described in detail with reference to the drawings. [Brief Description of the Drawings] [Figure 1] Fig. 1 is a view showing a structure of a motorcycle to which a vapor separation device according to the present invention is applied. [Figure 2] Fig. 2 is a partially cutaway side view of a strainer of a first embodiment to which the present invention is applied. [Figure 3] Fig. 3 is a top view of the strainer to which the present invention is applied. [Figures 4A and 4B] Figs. 4A and 4B are front and back views, respectively, of the strainer to which the present invention is applied. [Figure 5] Fig. 5 is a side view of a strainer of a second embodiment to which the present invention is applied. [Figure 6] Fig. 6 is a sectional view showing a structure of a jet valve provided in a return fuel passage. [Figure 7] Fig. 7 is a sectional view showing a structure of another jet valve provided in the return fuel passage. [Figure 8] Fig. 8 is a view showing a structure of a conventional art (No. 1). [Figure 9] Fig. 9 is a view showing a structure of a conventional art (No. 2). drawings. Fig. 1 is a view showing a structure of a motorcycle to which a vapor separation device according to the present invention is applied. A motorcycle 1 includes: a main frame 101 extending lower rearward from a head pipe 102; a front fork 103 attached to the head pipe 102; a front wheel 104 attached to a lower end of the front fork 103; a lateral pair of side arms 105 connected to the main frame 101; a rear fork 106; a rear wheel 107 and a shock absorber 108 attached to the bottom of the rear fork 106. -The rear fork 106 is pivotally supported by a pivot 121 provided on a bracket 114 . Under a seat 109, a luggage box 111 for housing a helmet and gloves is provided. In a portion under the main frame 101, an engine assembly 110 as a power unit is suspended on brackets 112, 113 and 114. Driving force generated in the engine assembly 110 is transmitted to the rear wheel 107 through a crankshaft 116 in a crankcase 115, a gear train (not shown) , and a chain in a chain case 118. The engine assembly 110 includes an air cleaner 122 and an air intake pipe 123 which are placed at a front portion of a body. Air is taken in through these and discharged, through an exhaust pipe, from a muffler placed at a rear portion of the body. On some point of the air intake pipe 123, a throttle body 125 having a built-in throttle valve and a pump injector 126 are provided. The pump injector 126 is connected to a fuel tank 129, which is placed at an upper rear portion of the body, by a fuel feed pipe 128 and a fuel return pipe 127 through a later-detailed strainer 120 according to the present invention, the strainer having a vapor separation function. The fuel feed pipe 128 and the fuel return pipe 127 are, for example, disposed next to the main frame 101. Fig. 2 is a sectional side view of the aforementioned strainer 120 having the vapor separation function. Fig. 3 is a top view thereof, and Figs. 4A and 4B are front and back views thereof, respectively. The strainer 120 of the present invention is mainly composed of: an inlet 301 through which feed fuel flows in from a fuel tank 129; a filter chamber 303 in which a filter 302 to filter feed fuel is housed; a vapor reservoir 304 provided on top of the filter chamber 303; an outlet 305 through which filtered feed fuel is supplied to a fuel pump; an inlet 306 through which return fuel applied with pressure flows in; a return fuel passage 307 through which return fuel is force-fed; an outlet 308 through which return fuel is discharged toward the fuel tank; and a vapor gas suction path 310 which communicates with the vapor reservoir 304 and the return fuel passage 307. To the inlet 301 through which feed fuel flows in, the fuel tank 129 is connected through the fuel feed pipe 128, and, to the outlet 305, the pump injector 126 is connected. Similarly, to the inlet 306 through which return fuel flows in, the pump injector 126 is connected through the fuel return pipe 127, and, to the outlet 308, the fuel tank 129 is connected. In such a structure, when return fuel is force-fed through the return fuel passage 307, suction force is generated in the vapor gas suction path 310 due to an injector effect, thereby developing a negative pressure in the vapor reservoir 304. Due to this negative pressure, in the filter chamber 303, suction force of the negative pressure acts on vapor gas contained in feed fuel in addition to ascending force of the vapor gas. Accordingly, it is possible to allow more vapor gas to ascend, which .enables efficient separation of vapor gas from feed fuel. Fig. 5 is a sectional side view of a strainer having a vapor separation function according to another embodiment of the present invention. The same reference numerals as the above denote the same or similar portions. In this embodiment, a jet valve 309 is provided in the return fuel passage 307 through which return fuel is force-fed. This embodiment is characterized in that an opening of the vapor gas suction path 310 on the return fuel passage side is provided on a downstream side of the jet valve 309. Fig. 6 is an enlarged sectional view of the vicinity of the jet valve 309. In this embodiment, the jet valve 309 is integrally formed with a housing member of the strainer. However, as shown in Fig. 7, formation may be performed by inserting a jet valve 311 inside the return fuel passage 307 integrally formed with the housing member. According to this embodiment, a flow rate of return fuel force-fed through the return fuel passage 307 is accelerated by means of the jet valve 309, and suction force larger than that of the first embodiment is generated in the vapor gas suction path 310. Therefore, vapor gas contained in feed fuel can be separated more efficiently. Note that, in the foregoing embodiment, it is described that the return fuel passage for return fuel is provided in the strainer 120, a negative pressure is generated due to the injector effect, and vapor gas is proactively separated from feed fuel by utilizing this negative pressure. However, the present invention is not limited to this and can be similarly applied to a device other than a strainer, namely, a vapor gas separation device without a filter in the filter chamber, which demonstrates only a vapor gas separation function and merely serves as a communicating passage. [Effects of the Invention] According to the present invention, effects like the following can be attained. (1) Vapor gas is sucked by utilizing a negative pressure generated due to a flow rate of the return fuel. Therefore, vapor can be efficiently removed without newly providing a power source for sucking and an electric power source therefor: As a result, favorable fuel without vapor gas can be supplied. (2) Suction force is increased when a flow rate of the return fuel is accelerated by means of the j et valve . Therefore, vapor can be removed more efficiently. (3) Vapor gas can be separated from the feed fuel by means of the strainer with the return fuel passage, the vapor reservoir and the vapor gas suction path provided therein. Therefore, vapor can be efficiently removed without increasing the number of parts. [Explanation of the Reference Numerals] 120...STRAINER, 126...PUMP INJECTOR, 127...FUEL RETURN PIPE, 128...FUEL FEED PIPE, 129...FUEL TANK, 301...FEED FUEL INLET, 302...FILTER, 303...FILTER CHAMBER, 304...VAPOR RESERVOIR, 305...FEED FUEL OUTLET, 306...RETURN FUEL INLET, 307...RETURN FUEL PASSAGE FOR RETURN FUEL, 308...RETURN FUEL OUTLET, 309...JET VALVE, AND 310...VAPOR GAS SUCTION PATH WE CLAIM: 1. A vapor gas separation device having an inlet and an outlet for feed fuel which separates vapor gas from the feed fuel flowed in from the inlet and discharges the vapor gas, characterized by comprising: a vapor reservoir provided on top of a communicating passage which communicates with the inlet and the outlet; a return fuel passage which discharges, from one end thereof, return fuel force-fed from the other end; and a vapor gas suction path of which one end is open to the return fuel passage and the other end is open to the vapor reservoir. 2. The vapor gas separation device as claimed in claim 1, wherein that the return fuel passage has a jet valve, and one end of the vapor gas suction path is open on a downstream side of the jet valve. 3. A strainer having an inlet and an outlet for feed fuel which filters the feed fuel flowed in from the inlet and discharges the feed fuel from the outlet, characterized by comprising: a filter chamber which communicates with the inlet and the outlet and includes a vapor reservoir on top thereof; a filter installed in the filter chamber; a return fuel passage as claimed in claim 1 which discharges, from one end thereof, return fuel force-fed from the other end; and a vapor gas suction path of which one end is open to the return fuel passage and the other end is open to the vapor reservoir. 4. The strainer as claimed in claim 3, wherein the return fuel passage has a jet valve, and one end of the vapor gas suction path is open on a downstream side of the jet valve. 5. A vapor gas separation device substantially as hereinbefore described with reference to the accompanying drawings.

Documents:

752-del-2004-abstract.pdf

752-del-2004-claims.pdf

752-del-2004-correspondence-others.pdf

752-del-2004-correspondence-po.pdf

752-del-2004-description (complete).pdf

752-del-2004-drawings.pdf

752-del-2004-form-1.pdf

752-del-2004-form-19.pdf

752-del-2004-form-2.pdf

752-del-2004-form-3.pdf

752-del-2004-form-5.pdf

752-del-2004-gpa.pdf

752-del-2004-petition-137.pdf

752-del-2004-petition-138.pdf

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