GB2382335A

GB2382335A - Fuel pump module

Info

Publication number: GB2382335A
Application number: GB0221571A
Authority: GB
Inventors: Naomasa Kaneko; Taiki Yanase; Shoji Sasaki; Kunio Miyauchi; Masaaki Horiuchi
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2001-09-17
Filing date: 2002-09-17
Publication date: 2003-05-28
Anticipated expiration: 2022-09-17
Also published as: MY130684A; GB2382335B; JP2003090274A; CN1408573A; GB0221571D0; TW534951B

Abstract

A fuel pump module includes an inlet filter (103 Fig. 5), a pump (104), a discharge tube (105) and strainer (106) with a pressure regulator 115 branching 111 from the discharge tube to return fuel to a tank through a return pipe 10 and tube end component 117. A discharge port (113) directs the fuel to an injector (120). To prevent resonant frequency noise generation the speed of fuel flow in the return pipe is varied along its length. This may be done by providing parts of differing diameter 13, 15 between the pipes 11, 12, 14 making up the return pipe; by providing sump portions (24, 25 Fig. 2) at points along the pipe; by providing a flexible diameter portion (42 Fig. 4) or by splitting the flow into two or more parallel paths (33, 34, 35 Fig. 3) which are then recombined.

Description

FUEL PUMP MODULE

The presentinvention relates toe technology for preventing generation of an abnormal sound or a vibration anticipated to arise from a fuel pump.

Aconventionalfuelpump module operates in accordance with a principle as illustrated in FIG. 5 hereof. The fuel pump module 10 102 is mounted to a fuel tank 101 at an upper end thereof. The fuel pump module 102 is comprised of a fuel pump 104 for drawing fuel through an inlet filter 103 and pressurizing the drawn fuel, a strainer 106 connected to a discharge tube 105 of the fuel pump 104, a discharge port 113 for directing a whole of or portion 15 of the fuel passing through the strainer 106 to an injector 120 via a feed pipe 112, as shown by arrow 03, a pressure regulator 115 having an inlet 111, diverged from the strainer 106, and an outlet 114 for returning a portion of the fuel to the fuel tank 101 when a pressure at the inlet 111 exceeds a given value, a 20 return pipe 116 extending a given length from the outlet 114, a tube end component 117 provided at a distal end of the return pipe 116, and a module case 118 for collectively accommodating all of the aforementioned components.

As can be appreciated from above, the name of the fuel pump 25 module 102 comes from the inherent capability of the module case 118, shown by phantom line, being fitted with and released from the fuel tank 101 in a single unit or like a module.

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Reference is made next to FIGS. 6A and 6B illustrating in cross section the pressure regulator 115 of FIG. 5.

In FIG. 6A, since a valve member 122 closes a valve seat 123 by the urging force of a spring 121, fuel does not flow to 5 the outlet 114 and the divergent inlet 111.

When the pressure exceeds the given level at the inlet 111, a force (directed leftward in the figure) acting on a diaphragm 124 overcomes the urging force of the spring121, with a resultant leftward displacement of the valve member 122.

10 As shown in FIG. 6B, the leftward displacement of the valve member 122 causes a portion of fuel to emit from the outlet 114 vie the inlet 111. When the pressure is lower than the given level at the inlet 111, then the valve member 122 is returned to its original position shown in FIG. 6A. Thus, the pressure regulator 15 115 serves as a pressure regulating unit for keeping the fuel pressure at the inlet 111 under a fixed level.

The fuel pump 104 of FIG. 5 generally adopts a structure in which a pump rotor is rotated at a high speed with an internally contained electric motor, whereby when a pump discharging 20 condition changes, the pump discharging condition passes across a resonant frequency probably for an extremely short period of time at which the fuel pump generates an abnormal sound, called a resonant sound.

To avoid such an occurrence, attempts have been made in 25 a conventional practice to take a measure to alter a flow rate characteristic of the fuel pump 104 per se, a measure to alter a valve characteristic of the pressure regulator 115 per se, and - 2 -

f-- - a measure for providing a supplemental cushion rubber to permit the fuel pump module 102 per se to be mounted to the fuel tank 101 via the cushion rubber, etc. However, the measure for the fuel pump and the measure for 5 the pressure regulator set forth above take a considerable time and expenses, leading to an increase in costs of the fuel pump module 102. Further, there exists a fear of adversely affecting a performance of feeding fuel to the engine in nature at a rate sufficiently necessary thereto.

lo In contrast, although it is easy for the cushion rubber to be added as the measure, the number of components, such as the cushion rubber, increases and, thus, the measure tends to spread over the fuel pumpmodule 102 and the fuel tank 101, resulting in an increase in the number of assembling steps when assembling 15 the fuel pump module 102 to the fuel tank 101.

It is therefore an object of the present invention to provide a measure which is replaceable with the measures set forth above.

The inventors have found that the change in the purl 20 discharging condition is a cause of occurrence of the abnormal sound and the change in the pump discharging condition is deeply caused by operative variation in the pressure regulator. In view of the above finding, the inventors have focused on the pressure regulator and have learned a provability of compelling the return 25 pipe, extending from the pressure regulator, to exhibit a resonant vibration preventive operation. To this end, fabricating return pipes in various shapes and conducting trials provide a success - 3 -

- in achieving the object with some kinds of particular configurations. According to an aspect of the present invention, there is provided a fuel pump module designed to be fitted with a fuel 5 tank, which module comprises: a fuel pump for drawing fuel and pressurizingthedrawnfuel; apressureregulatorhavinganinlet, diverged from a discharge tube of the fuel pump, and an outlet for returning a portion of the fuelto the fuel tank when a pressure at the inlet exceeds a given value; a feed pipe extending a given lo length from the discharge tube for directing a whole of or a portion of the fueltoaninjector; a return pipe extending a given length from the outlet; and a module case for accommodating all of the aforementioned components, characterized in that means for varying a rate of flow of the fuel through the return pipe is 15 provided midway of the return pipe to vary a resonant frequency for thereby precluding generation of an abnormal sound In a preferred form, the flow rate varying means comprises an enlarged diameter portion and/or a reduced diameter portion disposed midway of the return pipe. Provision of the enlarged 20 diameter section or the reduced diameter section midway of the return pipe allows the rate of flow of the fuel through the return pipe to be varied. This variation in the flow rate results in variation in the resonant frequency, with a resultant capability of preventing the occurrence of the abnormal sound. This measure 25 can be taken within the fuel pump module and, hence, there is no increase in the number of steps when assembling the fuel pump module to the fuel tank. In addition, since there is a mere need - 4

\ for modification in a shape of the return pipe, rather than modifying specifications of the fuel pump per se or the pressure

regulator per se, the measure can be taken at a low cost in an easy fashion.

5 Desirably, the flow rate varying means comprises a liquid sump portion additionally provided at an end or midway of the returnpipe. Bythusadditionallyprovidingtheliquideumpportion in the return pipe at the end or midway thereof, the flow rate ofthefuelflowingthroughthereturnpipecanbevaried,resulting 10 in capability of preventing generation of the abnormal sound.

This measure can be taken within the fuel pump module and, hence, there is no increase in the number of steps when assembling the fuel pump module to the fuel tank. In addition, since there is a mere need for modification in a shape of the return pipe, rather 15 than modifying specifications of the fuel pump per se or the

pressure regulator per se, the measure can be taken at a low cost in an easy fashion.

The flowratevaryingmeansmaycomprise two ormoredivergent tubes branched off midway of the return pipe. By thus arranging 20 the midway of the return pipe to be diverged into two or more branches, the rate of flow of the fuel through the return pipe is varied. Further, the diverging and confluence flows causes the flow rate to vary the resonant frequency. As a result, generation of the abnormal sound is prevented. This measure can z betakenwithinthefuelpumpmoduleand,hence,thereisnoincrease in the number of steps when assembling the fuel pump module to the fuel tank. In addition, since there is a mere need for - 5 -

- modification in a shape of the return pipe, rather than modifying specifications of the fuel pump per se or the pressure regulator

per se, the measure can be taken at a low cost in an easy fashion.

It is desired that the return pipe of the flow rate varying 5 meanscomprisesinpartarubbertubemadeofasoftrubbermaterial.

Provision of the return pipe partially comprised of the rubber tube of soft rubber materialallows the pipe to tee enlarged/reduced in diameter due to pressure of the fuel flowing through the return pipe. Enlargement/reductiOn in diameter causes a cross sectional lo - area to be varied, resulting in a variation in the flow rate at an area made of rubber-like soft material. This variation causes the variation in the resonant frequency, with a resultant capability of preventing the abnormal sound from teeing generated.

This measure can be taken within the fuel pump module and, hence, 15 there is no increase in the number of steps when assembling the fuel pump module to the fuel tank. In addition, since there is a mere need for modification in a shape of the return pipe, rather than modifying specifications of the fuel pump per se or the

pressure regulator per se, the measure can be taken at a low cost 20 in an easy fashion Certain preferred embodiments of the presentinvention will tee described in detailbelow,bywayofexampleonly,withreference to the accompanying drawings, in which: 25 FIG. 1 is an enlarged view illustrating part of a fuel pump module according to a first embodiment of the present invention; FIG. 2 is an enlarged view illustrating part of a fuel pump - 6

( module according to a second embodiment of the present invention; FIG. 3 is an enlarged view illustrating part of a fuel pump module according to a third embodiment of the present invention; FIG. 4 is an enlarged view illustrating part of a fuel pulp 5 module according to a fourth embodiment of the present invention; FIG. 5 is a schematic view illustrating a principle of a conventional fuel pump module; and FIGS. 6A and 6B are cross sectional views of a pressure regulator of FIG. 5.

Reference is made initially to FIG. 1 showing on an enlarged scale part of a fuel pump module according to a first embodiment.

The illustrated fuel pump module is a partially improved version of the one shown in FIG. 5 and hence like parts are designated 5 by like reference numerals.

The first embodiment features that a return pipe 10, which connects an outlet 114 of a pressure regulator 115 and a tube end con ponent 1I7 to one another, has an enlarged diameter portion 13 disposed between plastic tubes 11, 12 or a reduced diameter 20 portion 15 disposed between plastic tubes 12, 14.

The plastic tubes 11, 12, 14 have fixed inner diameters and, hence, there is no change in the flow rate of fuel passing through these components. But, the enlarged diameter portion 13 has a large inner diameter with a large cross sectional area and 25 the flow rate decreases. On the contrary, the reduced diameter portion 15 has a small inner diameter with small cross sectional area and the flow rate increases.

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That is, an attempt is made to vary the rate of flow of fuel through the return pipe 10. The presence of the variation in the flow rate induces a variation in a resonant frequency, with a resultant capability of precluding abnormal sound from 5 being produced.

Since this measure can be incorporated in the fuel pump module, no additional step is required when assembling the fuel pump module to a fuel tank. In addition, the need for modification in a shape of the return pipe 10, rather than modifying lo specifications of the fuel pump per se or the pressure regulator

115 per se, enables the measure to be taken at a low cost in an easy fashion.

Also, the reduced diameter portion 15 may include a constricted orifice which engages the plastic tubes 11, 12 or 15 14. Further, the return pipe 10 may be free to be provided with either one of or both of the enlarged diameter portion 13 and reduced diameter portion 15, and may be employed in an arbitrary number of or arbitrary length of the enlarged diameter portion 13 and reduced diameter portion 15.

20 FIG. 2 illustrates on an enlarged scale part of a fuel pump module according to a second embodiment, which is a partial improvement over the structure of FIG. 5. Thus, like parts are designated by like reference numerals.

The second embodiment is featured in that a return pipe 25 20, which interconnects the outlet 114 of the pressure regulator 115and the tube terminalendcomponent117,has divergent portions 22, 23, disposed at both ends of or in a midway of the plastic _ _

If'' - tube 21, to which liquid sump portions 24, 25 are connected.

Also,theliquidsumpportions24,25taketheformofchambers which are diverged from the return pipe 20 to assume respective mount positions different from that of the enlarged diameter 5 portion of the first invention located in the return pipe.

Now, at the time instant when fuel begins to flow through the return pipe 20, fuel is diverged into two streams which flow into the liquid sump portions 24, 25, resulting in a change in the flow rate of fuel passing through the return pipe 20. This 10 changein the flowrateresultsinachangein the resonant frequency, with a resultant capability of preventing abnormal sound from being generated.

Since this measure can be taken within the fuel pump module, no additionalstepisrequiredwhen assembling the fuelpumpmodule 15 to the fuel tank. In addition, the need for modification in a shape of the return pipe 20, rather then modifying specifications

of the fuel pump per se or the pressure regulator 115 per se, enables the measure to be taken at a low cost in an easy fashion.

Also, by locating the liquid sump portion 24 at a position 20 close proximity to the outlet 114 of the pressure regulator 115, the liquid sump portion 24 may be integrally formed with the pressure regulatorl15. In analternative,theliquid sump portion 25 may be integrally formed with the tube end component. These cases substantially correspond to the same structure as that in 25 which the liquid sump portions are mounted to the ends of the return pipe 20.

FIG. 3 illustrates on an enlarged scale part of a fuel pump _ 9 _

module according to a third embodiment, which is a partial improvement over the structure of FIG. 5. Thus, like parts are designated by like reference numerals.

The third embodiment features that a return pipe 30, which 5 interconnects the outlet 114 of the pressure regulator 115 and the tube end component 117, includes a main tube 31, a branch joint 32, a plurality of (three pieces in this example) of branch tubes 33, 34, 35, a confluence joint 36, a main tube 37 and a plastic tube 38. These components may be formed of any material lo such as plastic or metal.

Allowing the midway of the return conduit 30 to be diverged into two or more than two pieces enables changes in the flow rate of fuel passing through the return pipe 30, i.e., the flow rate varies at timings when the fuel flow is diverged at the branch 15 joint 32 and when the diverged streams join at the confluence joint 36. This change in the flow rate results in a change in the resonant frequency, with a resultant capability of preventing the abnormal sound from being generated.

Since this measure can be taken within the fuel pump module, 20 noadditionalstepisrequiredwhenassemblingthefuelpumpmOdule to the fuel tank. In addition, the need for modification in a shape of the return pipe 30, rather than modifying specifications

25 FIG. 4 illustrates on an enlarged scale part of a fuel pump module according to a fourth embodiment, which is a partial improvement over the structure of FIG. 5. Thus, like parts are -

- designated by like reference numerals.

The fourth embodiment features that a return pipe40, which interconnects the outlet 114 of the pressure regulator 115 and the tube end component 117, includes a plastic tube 41, a rubber 5 tube 42, tube clamps 43, 44 fixed at both ends of the rubber tube 42, and a plastic tube 45.

Forming a portion of the return pipe 40 with the rubber tube42 allows the return pipe40tobeenlarged/reducedindiameter due to a pressure of fuel flowing through the return pipe 40.

lo Since the return pipe 40 varies in cross sectional area due to enlargement/reduction in diameter, the flow rate varies at an area of the rubber tube 42. Due to this variation, the resonant frequency is varied, with a resultant capability of precluding the abnormal sound from being generated.

15 Since this measure can be taken within the fuelpump module, noadditional step is requiredwhenassemblingthefuelpumpmodule to the fuel tank. In addition, since there is a mere need for modification in a shape of the return pipe, rather than modifying specifications of the fuel pump per se or the pressure regulator

20 per se, the measure can be taken at a low cost in an easy fashion.

Also, a whole part of the return pipe 40 may be formed of the rubber tube 42. In such a case, since the outlet 114 of the pressure regulator 115 corresponds to the plastic tube 41 and the tube end component 117 corresponds to the plastic tube 45, 25 the operation set forth above can be expected.

Moreover, it is to be construed that the present invention takes a subject master related to the return pipe andisnotlimited - I1

to the particular internal structure of the fuel pump module of FIG. 5 involving the presence of or the absence of the strainer and a particular arrangement between the strainer and the fuel pump. - 12

Claims

1. A fuel pump module designed to be fitted with a 5 fuel tank, comprising: a fuel pump for drawing fuel and pressurizing the drawn fuel; a pressure regulator having an inlet, diverged from a discharge tube of the fuel pump, and an outlet for lo returning a portion of the fuel to the fuel tank when a pressure at the inlet exceeds a given value; a feed pipe extending a given length from the discharge tube for directing a whole of or a portion of the fuel to an injector; 15 a return pipe extending a given length from the outlet; and a module case for accommodating all of the aforementioned components, wherein means for varying a rate of flow of the fuel 20 through the return pipe is positioned along the return pipe to vary a resonant frequency for thereby precluding generation of an abnormal sound.

2. A module as claimed in claim 1, wherein the flow 25 rate varying means comprises an enlarged diameter portion and/or a reduced diameter portion disposed along the return pipe.

3. A module as claimed in claim 1, wherein the flow 30 rate varying means comprises a liquid sump portion provided at an end of or positioned along the return pipe.

4. A module as claimed in claim 1, wherein the flow 35 rate varying means comprises two or more divergent tubes branched off along the return pipe.

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5. A module as claimed in claim 1, wherein the return pipe of the flow rate varying means comprises in part a rubber tube made of a soft rubber material.

5

6. A fuel pump module, substantially as hereinbefore described and with reference to Figure 1, Figure 2, Figure 3 or Figure 4.