Fuel supply system

To provide a fuel supply system in which fuel stored in a fuel storage tank formed in a housing main body can be supplied by a high-pressure pump provided in the housing main body in spite of a rapid acceleration or a rapid deceleration of an engine, two types of connectors, which is a first connector having a low-pressure pump having a connection port for a fuel supply pipe from a fuel tank and a second connector having no pump, can be selectively attached via a common connector mounting part formed on a wall surface of a housing main body, and by using a housing having therein the commonly used high-pressure pump, a fuel supply system using an external pump and a fuel supply system using no external pump can be respectively manufactured in accordance with the purpose of use.

BACKGROUND

The present invention relates to an improvement of a fuel supply system provided in the middle of a fuel supply pipe, as described in U.S. Pat. No. 6,390,871 and JP 2013-516576 W (PCT/US2011/020454), to supply liquid fuel stored in a fuel tank to an engine.

When supplying the liquid fuel stored in the fuel tank to the engine, it is necessary to continuously supply fuel even if there is a rapid acceleration or a rapid deceleration, and it is also necessary to prevent evaporation of the fuel due to high temperatures generated by operation of the engine.

In order to address this issue, conventionally, U.S. Pat. No. 6,390,871 proposes an engine control module equipped with two pumps in a reserve tank, for example. This engine control module is provided in the reserve tank with a first fuel pump as a draw-up pump for drawing up the fuel from a fuel tank to a reserve tank and a second fuel pump for feeding the fuel drawn-up into the reserve tank into a fuel rail of the engine at a higher pressure; thus, the engine control module has advantages of saving pipes for a fuel pipe, easy manufacturing, and further prevention of fuel leakage. However, this prior art has two fuel pumps disposed in the reserve tank, and thus has issues that assembly and mounting are cumbersome and the production cost is high.

In order to solve these problems, JP 2013-516576 W (PCT/US2011/020454) proposes a vapor separator (fuel pump). As shown inFIG. 7, a vapor separator (seeFIG. 6) is proposed in which there is disposed in the reserve tank RT a high-pressure pump P2for feeding the fuel drawn-up in the reserve tank RT into the fuel rail of an engine at a higher pressure and there is disposed a low-pressure fuel pump P1which is constituted by a pulse pump for drawing up the fuel from the fuel tank to the reserve tank RT and is integrally formed on the outside of the reserve tank RT, for example; thus, the vapor separator can be assembled more easily and be provided at a lower price.

However, this fuel supply system (vapor separator) is a system, in which the pulse pump as the low-pressure pump P1is formed on a housing H having the reserve tank RT integrally and indivisibly, and which has to have two pumps; thus, there is a big problem that the fuel supply system cannot be applied to a system which supplies a sufficient amount of fuel to the engine by using, for example, the reserve tank RT and the second high-pressure pump P2even when the rapid acceleration or the rapid deceleration occurs.

SUMMARY

The present invention relates to improvement to a conventional fuel supply system having a reservoir provided in the middle of the fuel supply pipe to supply the stored liquid fuel in the fuel tank to the engine, and an object of the invention is to provide a fuel supply system which is useful for many purposes and is excellent in cost.

The present invention includes: a housing configured to have a lid body airtightly covering an opening formed in an upper surface of a housing main body which forms a fuel storage tank which doubles as a reservoir, and configured to have, in a sidewall of the housing main body, a fuel intake port communicating with the fuel storage tank; a high-pressure pump provided in the housing main body to supply fuel stored in the fuel storage tank to an engine; and a connector which is integrally attachable to the sidewall of the housing main body, the connector including: a fuel-feeding port configured to be in touch with and communicate with the fuel intake port formed in the wall surface when the fuel-feeding port is attached to the sidewall; and a connection port configured to communicates with the fuel-feeding port and to accept a fuel supply pipe from a fuel tank, wherein the connector includes a two types of connectors including a first connector having a low-pressure pump and a second connector having no pump, and wherein the two types of connectors is selectively attachable via a common connector mounting part formed on the sidewall of the housing main body. Thus, by using a common housing in which a high-pressure pump is installed, a fuel supply system using an external pump and a fuel supply system using no pump can be manufactured.

Further, a configuration is made such that in the fuel storage tank formed in the housing main body, there is provided a float having a regulator function for keeping a liquid surface of the fuel stored in the fuel storage tank at a predetermined position; thus, the regulator function can be installed in a small space.

Further in the present invention, the fuel intake port formed in the wall surface of the housing main body is formed above a liquid surface of the stored fuel; thus, even in the case that the external pump is not used, the fuel can be taken in, by free fall, from the fuel tank into the fuel storage tank formed in the housing main body.

The high-pressure pump can be easily and securely installed in the housing main body by a lower part of the high-pressure pump being held by pressure against a holding member which is provided on a bottom part of a fuel storage part of the housing main body, is formed of a resilient material, and has a flow passage communicating with the fuel storage part, in such a manner that a suction port is opened to the flow passage. In addition, a blitz type filter is provided on the holding member provided on a bottom part of a fuel storage part of the housing main body in such a manner that a feed-out port is opened to a flow passage, and a lower part of the high-pressure pump is held by pressure in such a manner that a suction port is opened to the flow passage; thus, a plurality of components can be fixed with the single holding member.

Still further, the high-pressure pump includes a connection electrode on an upper part thereof, and the connection electrode is provided to penetrate through the lid body; thus, it can be easy to install the pump and secure airtightness of the housing, whereby the number of components is reduced, and electric connection and electrical maintenance are simple. In addition, because the housing main body and the lid body are fixed to each other with a spring clip, assembly and disassembly are easy and the airtightness of the housing can be maintained.

In addition, a threaded hole, which is of threaded holes formed in the wall surface of the housing main body to receive fixing bolts for fixing a first connector having a low-pressure pump and is formed on a bottom part, and a drain reservoir formed to be recessed in a bottom surface of the housing main body are communicated with each other through a drain passage having a smaller diameter than the threaded hole; and drain (water or impurities contained in the fuel) stored in the drain reservoir can be discharged through the threaded hole and the drain passage, whereby the drain stored in the bottom part in the housing main body is easily made to discharge from outside of the housing.

In addition, a positioning pin is integrally provided protrudingly at a predetermined position on an opening edge of the housing main body, and a positioning hole which fits the positioning pin is formed in a flange of the lid body to be in contact with and opposed to the opening edge of the housing; thus, it goes without saying that sealing can be easily and surely done, and because the positioning pin protrudingly provided on the housing main body is fixed at a predetermined fitting position, the action of fixing the lid body on the housing main body can also be provided.

Further, in the case that a holding member holding a regulator used in the present invention is in an arched shape as a whole and has leg parts protrudingly provided on lower surfaces of both ends of the holding member, the both ends being configured to be placed on support plates each of which is protrudingly provided on each of mutually opposing inner wall surfaces of the fuel storage tank, on a part of a surface of a holding member main body which has a length long enough for at least one end part to be close to the inner wall surface of the fuel storage tank, there is formed on an upper end surface a receiving surface on which a holding flange protrudingly provided on a circumferential wall of a pressure regulating unit main body of a regulator, and a regulator receiving part made up of a recessed part for holding the regulator with a space between the regulator receiving part and a return port of the regulator; and an extra fuel discharge passage in a gutter shape communicating with the space of the regulator receiving part is formed in the surface of the holding member main body from the regulator receiving part to the end part close to the inner wall surface of the fuel storage tank, since extra fuel from the regulator is returned to the fuel stored in the fuel storage tank along the inner wall surface of the fuel storage tank from a tip of the extra fuel discharge passage, it is possible to eliminate the fluctuation of the amount of the stored fluid caused by the disturbance of the liquid surface due to the extra fuel from the regulator flowing down into the fuel stored in the fuel storage tank, whereby the fuel can be stably supplied to the engine by the high-pressure pump.

DETAILED DESCRIPTION

FIGS. 1 to 6show a first embodiment which is a preferred embodiment of the present invention, and a fuel supply system as the present invention is configured with: a housing1which has a lid body2airtightly covering an opening13of a housing main body11having an opening in an upper surface, a bottom, and a fuel storage tank12formed therein; a high-pressure pump3provided in the housing main body11for discharging fuel stored in the fuel storage tank12through a fuel discharge pipe21formed in the lid body2; a first connector4which is detachably and integrally attached on one wall surface14of the housing main body11and to which a fuel pipe (not shown) is connected from a fuel tank (not shown) and which have a low-pressure pump41constituted by, for example, a low-pressure diaphragm pulse pump for supplying into the fuel storage tank12in the housing main body11; and a second connector5which is detachably and integrally attached on the one wall surface14of the housing main body11and to which a fuel pipe is connected from the fuel tank (not shown) and which have no pump for supplying into the fuel storage tank12in the housing main body11. Note that the low-pressure pump41is a pump similar to a conventional low-pressure pump of this type in which a pulsing motion from, for example, a crankcase of the engine is used.

Thus, any one of the first connector4and the second connector5is selected and used.

In more detailed description, the high-pressure pump3is installed to be held by pressure and to be fit in a mounting recess61of a holding member6which is installed on the bottom part of the housing main body11, is formed of a resilient material such as synthetic rubber, and has a flow passage62on a bottom part thereof communicating with the fuel storage tank12, such that a suction port31provided at the lower end of the high-pressure pump3is opened to the flow passage62and such that electrode part32formed at an upper end of the high-pressure pump3sticks out through the lid body2so that an electric connection can be made outside the housing1.

In addition, on another mounting recess63which is formed on the holding member6and communicate with the flow passage62, a blitz type filter7is also installed such that a feed-out port71is opened to the flow passage62.

Further, in the wall surface14of the housing main body11, a mounting part is formed to detachably attach, with a fixing bolt51, the first connector4having the low-pressure pump41or the second connector5, and there is formed a fuel intake port15with which, specifically when the first connector4or the second connector5is attached, a feed-out port42of the low-pressure pump41of the first connector4or a supply port52of the second connector5is airtightly fit. In addition, the fuel intake port15is positioned at least above a liquid surface of the fuel stored in the fuel storage tank12, and the fuel intake port15communicates with the fuel storage tank12through a fuel passage16and a valve body17which are provided in the housing main body11and the lid body2.

In the lid body2, there is provided a float8for determining a liquid surface position of the fuel stored in the fuel storage tank12. In the float8, there is provided a regulator9, in a penetrating manner, communicating between the fuel storage tank12and the fuel discharge pipe21which is disposed in the lid body2and is connected to a feed-out port33of the high-pressure pump3.

In the present embodiment, the lid body2is fixed with a plate-like spring clip10, and assembly and disassembly are thus easy.

The present fuel supply system having the above configuration is assembled by using any one of the first connector4having a low-pressure pump41or the second connector5having no pump, in accordance with the purpose of use. Of course, the connecter can be replaced with the other connector after once attached.

The assembled present embodiment is fixed to an engine, a vehicle body, or the like (not shown) via a mounting part18protrudingly provided on the housing1. The fuel introduced through the first connector4or the second connector5from the fuel tank (not shown) is introduced through the fuel intake port15formed in the wall surface14of the housing main body11and further through the fuel passage16formed in the lid body2and the valve body17into the fuel storage tank12and is stored up to a predetermined liquid surface by the float8. At the same time, the high-pressure pump3is operated to discharge the fuel in the fuel storage tank12through the fuel discharge pipe21.

FIGS. 8 to 14show a second embodiment of the present invention, and in the second embodiment, a drain reservoir19is formed to be recessed in a bottom part of a fuel storage tank12formed in a housing main body11; and in order to fix, for example, a lower part of a first connector4having a low-pressure pump41, the threaded hole20a, which is of threaded holes for fixing bolts51formed in a wall surface14of the housing main body11and is formed in a bottom part, and the drain reservoir19formed to be recessed in the bottom surface of the housing main body11are communicated with each other through a drain passage20having a smaller diameter than the threaded hole20a.

Therefore, drain (water or impurities contained in the fuel) stored in the drain reservoir19can be discharge through the threaded hole20aand the drain passage20by pulling out a fixing bolt51a, whereby the drain stored in the bottom part in the housing main body11can be very easily made to discharge from outside of the housing1.

In particular, in the present configuration, in the case that the second connector5having no pump as shown inFIG. 10is used, the fixing bolt51acan be used only for draining; however, the present configuration can be applied to the case that the first connector4having the low-pressure pump41shown inFIG. 9is used.

In the second embodiment, the threaded hole20afor the first connector4having the low-pressure pump41is made in the wall surface14of the housing main body11to have a predetermined length in correspondence to the position at which the drain reservoir19is formed in the bottom part of the housing main body11as shown inFIG. 14, and next the drain passage20having a smaller diameter than the threaded hole20ais easily made by additional machining, and because the drain passage20has a smaller diameter than the threaded hole20a, the function of the threaded hole20ais never impaired.

FIGS. 15 to 19show a third embodiment of the present invention. In the third embodiment, a housing1has: a housing main body11in which a fuel storage tank12is formed; and a lid body2which hermetically covers an opening13of the housing main body11through a packing300by using spring clips10. In the housing1, a positioning pin101is integrally provided protrudingly at a predetermined position on an opening edge100of the housing main body11, and a positioning hole201which fits the positioning pin101is formed on a flange200of a lid body2which is in contact with and opposed to the opening edge100of the housing.

Therefore, a positioning hole201formed in the lid body2is inserted into the positioning pin101protrudingly provided in the opening edge100of the housing main body11, in a process of putting the lid body2on the housing main body11, so that the lid body2is mounted at a predetermined position of the housing main body11.

Next, the lid body2is fixed on the housing main body11with separately provided fixing devices, for example, spring clips10, and the positioning pin101protrudingly provided on the opening edge100, of the housing main body11, protruding from the positioning hole201formed in the lid body2as shown inFIG. 17(a)is caulked as shown inFIG. 18(a), whereby a swelling caulked part105is generated to seal.

With the third embodiment, it goes without saying that sealing can be easily and surely done, and because the positioning pin101protrudingly provided on the housing main body11is fixed at a predetermined fitting position, the action of fixing the lid body2on the housing main body11can also be realized.

Then, if the lid body2is intentionally opened after being sold, the caulked part105should be broken; thus, it is easy to check that the lid body2was opened, and if the lid body2was opened and the caulked part105was broken, it is impossible to caulk again.

In addition, as shown inFIG. 19, the positioning pin101is constituted of a large diameter part102formed on a base end side and a small diameter part103formed on a tip side from the base end side, and in the positioning hole201in which the positioning pin101is fit, there are continuously formed a large diameter part202and a small diameter part203to fit the positioning pin101as shown inFIG. 17(b)andFIG. 18(b), and the two parts having the different diameters surely fit and support, whereby the lid body2can be surely disposed at an accurate position.

In particular, in the third embodiment, the large diameter part102of the positioning pin101has a circular cross-section, and the small diameter part103formed on the tip side from the large diameter part102has a semi-circular cross-section in which the large diameter part is cut away by a half of a diameter of the large diameter part for a predetermined height in the vertical direction; thus, the large diameter part102and the small diameter part103can be previously formed by integrally molding, however, may be formed by other processing methods such as cutting work.

In addition, in the third embodiment, because central axial lines of the large diameter part102and the small diameter part103constituting the positioning pin101and central axial lines of the large diameter part202and the small diameter part203of the positioning hole201are out of alignment, the lid body2can be disposed at a very precise position.

Note that caulking is performed by using conventional well-known method such as hitting or the like when the positioning pin101is made of metal, and thermal melting method when the positioning pin101is made of synthetic resin; therefore, the material does not need to be specifically limited.

Further, the third embodiment describes the case that the positioning pin101is formed on the housing main body11and the positioning hole201is formed in the lid body2; however, it goes without saying that, to the contrary, the third embodiment can be similarly practiced in the case (not shown) that the positioning pin101is formed on the lid body2and the positioning hole201is formed in the housing main body11.

Still further, in the third embodiment, fixing effect of the lid body2can be improved by caulking the positioning pin101, and when the number of the positioning pin101is increased, not only is the positioning accuracy of the lid body2on the housing main body11is improved, but also the fixing effect is improved. Therefore, the positioning pin101can be used as a fixing device, for example.

FIGS. 20 to 26show a fourth embodiment of the present invention, and a fuel supply system in the present embodiment has: a housing1having a lid body2which hermetically covers an opening13of a housing main body11which has a bottom and the opening13on an upper surface and in which a fuel storage tank12is formed; a fuel pump (high-pressure pump)3which takes in fuel stored in the fuel storage tank12disposed in the housing main body11from a suction port31through a filter7and discharges the fuel from a fuel discharge pipe21formed on the lid body2of the housing main body11; and a connector (second connector)5which is integrally and detachably mounted on one wall surface14of the housing main body11and has a supply port52for supplying the fuel into the fuel storage tank12of the housing main body11through a fuel pipe (not shown) connected to a fuel tank (not shown).

Note that, the fuel pump (high-pressure pump)3is disposed such that electrode parts32formed on the upper end of the fuel pump (high-pressure pump)3are protruded from the lid body2to be able to be electrically connected outside the housing1.

In addition, on the wall surface14of the housing main body11, the connector (second connector)5is detachably mounted with fixing bolts51, and the fuel is supplied to the fuel storage tank12from a fuel intake port15disposed above at least a liquid surface of the fuel stored in fuel storage tank12.

Further, in the fuel storage tank12, there is disposed a float8which has a mechanism for determining the liquid surface position of the fuel stored in fuel storage tank12, and the float8is swingably attached with a hinge81disposed, on the inner wall surface of the lid body2, at a position above an inner wall surface121of the fuel storage tank12.

Still further, in the fuel storage tank12, a holding member400disposed above the float8in the fuel storage tank12holds a regulator9in which pressure regulating ports92are connectingly provided on the upper part of a pressure regulating unit main body91containing therein a pressure regulating member (not shown) and in which a return port93is connectingly provided at the lower part of the pressure regulating unit main body91, wherein the pressure regulating ports92are being connected to the fuel discharge pipe21on the lid body2of the housing main body11.

In more detail, a holding member400holding a regulator9used in the present embodiment has the holding member main body404which is in an arched shape as a whole and has leg parts401and402protrudingly provided on lower surfaces of both ends of the holding member main body404as shown inFIG. 22, the leg parts401and402being configured to be placed on support plates123and124each of which is protrudingly provided on each of mutually opposing inner wall surfaces121and122of the fuel storage tank12. The holding member main body404has a length long enough for at least one end part403thereof to be close to the inner wall surface121of the fuel storage tank12. On a part of a surface of the holding member main body404, there is formed on an upper end surface a receiving surface405on which a holding flange94protrudingly provided on a circumferential wall of the pressure regulating unit main body91of the regulator9, and a regulator receiving part406made up of a recessed part for holding the regulator9with a space (not shown) between the regulator receiving part406and the recessed part of the return port93of the regulator9; and an extra fuel discharge passage407in a gutter shape communicating with the space of the regulator receiving part406is formed in the surface of the holding member main body404from the regulator receiving part406to the end part403close to the inner wall surface121of the fuel storage tank12.

In the embodiment having the above configuration is assembled such that the lid body2is fixed on the housing main body11with the plate-like spring clips10, and is used being fixed on an engine, a vehicle body, or the like (not shown) through the mounting part18protrudingly provided on the housing1; the fuel from the fuel tank (not shown) flows into fuel storage tank12through the connector (second connector)5mounted on the wall surface14of the housing main body11with the fixing bolts51as described above, is led into the fuel storage tank12through a fuel tank (not shown) and a valve body17disposed in the lid body2, and is then stored up to a predetermined liquid surface by the float8; and the fuel pump (high-pressure pump)3concurrently operates to discharge the fuel in the fuel storage tank12from the fuel discharge pipe21.

Thus, when a fluid pressure in a fuel supply pipe2is higher than a predetermined value, the regulator9operates to flow extra fuel from pressure regulating ports92connected to the fuel supply pipe2to the return port93so that the extra fuel is returned into the fuel storage tank12; thus, the fuel at a predetermined pressure is supplied to the engine. In this operation, because the regulator9is held on a novel holding member400in the present embodiment, the fuel does not directly flow down to the liquid surface of the fuel as in conventional arts, whereby the liquid surface is not disturbed.

That is to say, in the present embodiment, the extra fuel flowing out from the return port93of the regulator9does not directly go down on the liquid surface of the fuel stored in the fuel storage tank12as in conventional arts, but the extra fuel is stored, returning from the regulator receiving part406of the holding member400through the extra fuel discharge passage407and along the inner wall surface121of the fuel storage tank12from the end part403, whereby there is no chance for the extra fuel flowing down from the regulator9to disturb the liquid surface, and as a result, the supply of fuel from the fuel pump (high-pressure pump)3does not become unstable due to the disturbance of the liquid surface. In addition, in the present embodiment, because the extra fuel flows down along the inner wall surface121on the hinge81side which affects less the oscillation of the float8, the float8is not likely to oscillate, whereby supply can be more stable.

In addition, in the present embodiment, because the holding member400has an arched shape as a whole, the holding member400is therefore strong against load, and because the holding member400has the receiving surface405on which the holding flange94protrudingly provided on the circumference of the pressure regulating unit main body91of regulator9is placed, the holding member400can surely support the regulator9.

Further, in the present embodiment, as shown inFIG. 26, in the holding member400, on the holding member main body404, there is a supporting shaft409which has a predetermined height and is erected in correspondence to the position of a communication passage22which is formed in the lid body2and open to atmospheric air; and on a tip surface of the supporting shaft409, there is formed a receiving surface408for receiving a ball24which is used as a stopper and is inserted in an engaging recessed part23formed in a base end of the communication passage22.

With this arrangement, in a case that the housing1is laterally overturned, the ball24used as a stopper disposed on the receiving surface408closes the communication passage22open to atmospheric air so as to prevent the fuel stored in the fuel storage tank12from spilling out.