Fuel filter device

A filter element is formed from a filter material configured to capture a foreign substance in fuel. A lower case is attachable to and detachable from a bottom portion of a housing in a movable direction. The housing and the lower case are configured to accommodate the filter element. The filter element defines a passage extending through the filter element in the movable direction. The passage is configured to accommodate the component. The component is configured to be attached to and detached from the housing together with the lower case when the lower case is attached to and detached from the housing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and incorporates herein by reference Japanese Patent Applications No. 2007-262319 filed on Oct. 5, 2007 and No. 2008-163836 filed on Jun. 23, 2008.

FIELD OF THE INVENTION

The present invention relates to a fuel filter device for filtering fuel.

BACKGROUND OF THE INVENTION

For example, a fuel filter device is provided in a fuel supply unit, which is provided between a fuel tank and a fuel injection pump for supplying fuel into a diesel engine or the like. The fuel filter device is configured to capture an organic foreign substance such as dust or an inorganic foreign substance such as metal in fuel, for example. The fuel filter device includes a filter element formed from a filter material for capturing the foreign substance in fuel.

A fuel filter device may include an additional component having a predetermined function to cope with a predetermined fuel environment. For example, according to JP-A-2006-105092, a fuel filter device is provided with a metal ion capturing material as the additional component for capturing metal ions in fuel, which cannot be substantially captured by the filter element. JP-A-2006-105092 discloses a configuration where the metal ion capturing material is inserted between two filter elements, which are collectively accommodated in a case.

While description is not made in JP-A-2006-105092, a metal ion capturing material is reduced in capturing capability after use. The metal ion capturing material reduced in capturing capability needs to be removed from the case, and a new or degenerated metal ion capturing material needs to be loaded into the case. However, in the structure of JP-A-2006-105092, the metal ion capturing material is inserted between the two filter elements. Therefore, the metal ion capturing material needs to be removed from the case together with filter elements being not necessary to be removed, and another metal ion capturing material needs to be loaded into the case together with different filter elements. That is, the metal ion capturing material cannot be easily loaded into and removed from the fuel filter device independently of the filter elements. Such a problem lies not only in the metal ion capturing material, but also lies in a component such as an auxiliary filter element for capturing particulate matters having a larger diameter than a diameter of particulate matters that can be captured by a filter element.

SUMMARY OF THE INVENTION

In view of the foregoing and other problems, it is an object of the present invention to produce a fuel filter device including a component capable of being easily attached to and detached from the fuel filter device independently from a filter element.

According to one aspect of the present invention, a fuel filter device comprises a filter element formed from a filter material configured to capture a foreign substance from fuel. The fuel filter device further comprises a component. The fuel filter device further comprises a housing. The fuel filter device further comprises a lower case being attachable to and detachable from a bottom portion of the housing in a movable direction. The housing and the lower case are configured to accommodate the filter element and the component. The filter element defines a passage, which extends through the filter element in the movable direction. The passage is configured to accommodate the component. The component is configured to be attached to and detached from the housing together with the lower case when the lower case is attached to and detached from the housing.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

First Embodiment

InFIG. 1, a fuel supply unit100includes a fuel tank101, a fuel filter device1, a fuel injection pump102, a common rail103, a fuel injection valve104, a piping106for connecting the present components to one another, and an engine control unit (ECU)105. Fuel101A stored in the fuel tank101is fed by the fuel injection pump102into the common rail103via the fuel filter device1, and accumulated in the common rail103at high pressure. The fuel at high pressure accumulated in the common rail103is supplied to the fuel injection valve104and injected into an internal combustion engine (not shown) from the fuel injection valve104.

An operation of each of the fuel injection pump102, the common rail103, and the fuel injection valve104is controlled by the ECU105including a microcomputer having a well-known structure such that fuel is supplied from the common rail103into the fuel injection valve104at a specific timing so as to enhance fuel efficiency, for example.

The fuel101A is fed from the fuel tank101into the fuel filter device1, and a foreign substance such as a metal ion or a particulate matter contained in the fuel101A is captured in the fuel filter device1, and then the fuel is fed into the fuel injection pump102. The fuel101A flows into the fuel filter device1from an inlet pipe (inlet port)2as a part of the piping106. The fuel101A further flows out from an outlet pipe (outlet port)3as a part of the piping106. The fuel filter device1has a level switch11described later and is configured to light an indicator107according to an alarm signal from the level switch11.

As shown inFIG. 2, the fuel filter device1includes an element4having a filter element41and a center cylinder42, a component5, a connection member6, a case having a housing7, a cap9being a lower case, a drain bolt10, and a level switch11.

The cap9is formed in a manner of being attachable in an attachment direction Z to the housing7at a side of a bottom74of the housing7. The cap9is also formed in a manner of being detachable in a detachment direction Z from the housing7. Specifically, the cap9has a screw portion91, and the cap9is rotated in a rotation direction with the attachment and detachment directions (movable direction) Z as a rotation axis with respect to a coupling member83fixed to the housing7. Thus, the screw portion91of the cap9is screwed with a screw portion of the coupling member83, and hence the cap9is attached to the housing7. In addition, the cap9is rotated in a direction opposite to the rotation direction in attachment with respect to the coupling member83fixed to the housing7, so that the cap9is detached from the housing7. A space between the cap9and the housing7is sealed by an O-ring92. The cap9is attached to the housing7, thereby a case is formed, which accommodates the element4, the component5, and the connection member6.

The housing7includes an upper housing71made of resin or metal and a lower housing72made of metal. An inlet pipe2through which the fuel101A flows into the fuel filter device1and an outlet pipe3through which the fuel101A flows out from the fuel filter device1are fixed to the upper housing71. The fuel filter device1is configured such that the fuel101A flows from the inlet pipe2into the fuel filter device1along a passage F1. The fuel101A then passes through a metal ion capturing material51(FIG. 4) of the component5and the filter element41of the element4along passages F2and F3, and then flows out from the outlet pipe3along a passage F4. Moreover, a sediment reservoir (reservoir space)73is provided below the filter element41within the case (lower housing72). The sediment reservoir is a reservoir space for storing water separated from the fuel101A by using difference in specific gravity between the fuel101A and water.

The filter element41is formed from a filter material configured to capture particulate matters in the fuel101A passing through the filter element41. The present filter material is formed from filter paper or a nonwoven fabric having a pore size that enables capture of the particulate matters. The center cylinder42is provided at a center side of the filter element41. An inner space of the center cylinder42configures a passage44for the fuel101A. The passage penetrates the filter element41in the attachment and detachment directions Z of the cap9, as shown inFIG. 3.

The element4mainly includes the filter element41. The center cylinder42is formed in an annular disk shape using metal such as a spring steel. The element4and the center cylinder42are supported by a lower supporting member82and fixed within the lower housing72by an upper supporting member81via a seal member811. The seal member811seals a space between a clean side at a side of the lower housing72and an unclean side at a side of the upper housing71. A space between the upper housing71and the upper supporting member81is sealed by an O-ring711.

As shown inFIGS. 2 and 3, the component5is provided in the passage44. A space between the component5and the center cylinder42is sealed by an O-ring43. In thee present structure, the fuel101A in the passage F2passes through the metal ion capturing material51in the component5. As shown inFIG. 4, the component5includes the granular metal ion capturing material51, a mesh55to be filled with the metal ion capturing material51, a pipe-shaped pipe case52for holding the mesh55filled with the metal ion capturing material51, and a plate53. The pipe case52and the plate53are integrally formed from resin.

The metal ion capturing material51captures metal ions in the fuel101A passing through the metal ion capturing material51. For example, the metal ion capturing material51is formed from chelate resin (CR20 manufactured by Mitsubishi Chemical Corporation) configured to capture a metal ion by forming a chelate (complex) with the metal ion. The chelate resin is granularly formed, thereby surface area of the metal ion capturing material51is increased, so that metal ion capturing performance of the metal ion capturing material51is enhanced.

The chelate resin may not be granularly formed. Alternatively, the chelate resin may be formed in a fibrous shape or the like to increase the surface area of the metal ion capturing material51. In addition, the metal ion capturing material may be formed from ion exchange resin, which is configured to capture metal ions by using ion exchange, instead of the chelate resin.

Since both ends of the pipe case52are opened, the fuel101A passes through the metal ion capturing material51via the mesh55along the passage F2while metal ions in the fuel101A are captured by the metal ion capturing material51. The fuel101A, from which metal ions have been captured, passes through the mesh55, and then flows out from the pipe case52along the passage F3.

Since the metal ion capturing material51with the mesh55are accommodated in the pipe case52so as to be formed in a unit, the metal ion capturing material51is easily replaced. A configuration may be used, in which the mesh55stops up the opening at either end of the pipe case52, rather than the configuration in which the mesh55is filled with the metal ion capturing material51.

In this way, the component5is configured to capture the metal ions by including the metal ion capturing material51configured to capture metal ions in the fuel101A.

The component5is configured to be loaded into the housing7along with attachment of the cap9to the housing7. In addition, the component5is configured to he removed from the housing7along with detachment of the can9from the housing7. Specifically, the component5is connected to the cap9via the connection member6, thereby the component5can be loaded into and removed from the housing7together with the lower case. Moreover, as described before, the component5is provided in the passage44for the fuel101A, the passage penetrating the filter element41in the attachment and detachment directions Z of the cap9. Therefore, the component5can be attached to and detached from the housing without causing interference with the filter element41in the attachment and detachment directions Z of the cap9. That is, the component S can be loaded into and removed from the housing7independently of the filter element41in the attachment and detachment directions Z of the cap9.

In the present structure, the component5can be loaded into and removed from the housing7independently of the filter element41along with attachment and detachment of the cap9to/from the housing7. That is, the component5having the function of capturing metal ions in the fuel101A can be easily loaded into and removed from the fuel filter device1independently of the filter element41.

As shown inFIGS. 4 to 7, the connection member6includes three fitting portions617a ring-shaped first reinforcement plate63, a semi-ring-shaped second reinforcement plate64, a semi-ring-shaped third reinforcement plate65, and a semi-ring-shaped fourth reinforcement plate66, which are integrally formed from resin. The connection member6is connected to the cap9via caulking portions93, and connected to the component5via the three fitting portions61.

Each of the caulking portions93is formed by thermally caulking the cap9made of resin and the fourth reinforcement plate66made of resin. The connecting portion between the connection member6and the cap9are not limitedly made in such a way, For example, a cap9made of metal and the fourth reinforcement plate66made of resin may be connected by hooking or screwing.

InFIGS. 6 and 7, portions other than the connection member6are omitted for better viewing of drawings.

A claw62is formed at an end of each fitting portion61. As shown inFIG. 8, windows54are formed in the plate53of the component5, each window54being an opening to be fitted with each fitting portion61. That is, the plate53of the component5and the connection member6configure a connecting portion between the component5and them cap9.

The cap9is rotated with respect to the housing7(a fitting member83) in a circumferential direction (first and second directions) R1or R2inFIG. 2, that is, in a rotational direction, and the cap9is attached to or detached from the housing7. The window54includes first, second and third portions. The first portion has a first width W1as a radial width larger than a radial width of the fitting portion61. The second portion has a second width W2as a radial width smaller than the radial width of the fitting portion61. The third portion has third a radial width, which is between the first width W1and the second width W2.

In the present structure, when the cap9is rotated with respect to the housing7to be attached to or detached from the housing7, the fitting portion61can move within the window54along the circumferential direction R1or R2. That is, when the cap is attached to and detached from the housing7, the fitting portion61can move along the circumferential direction R1or R2. An arrow R1shows a direction along which the fitting portion61moves within the window54when the cap9is attached to the housing7. An arrow R2shows a direction along which the fitting portion61moves within the window54when the cap9is detached from the housing7.

When the cap9is attached to the housing7, the plate53of the component5and the fitting portion61of the connection member6are in the condition shown inFIG. 8. In the present condition, the fitting portion61is inserted into the first portion of the window54having the first width W1. As shown inFIGS. 8 and 9, the first width W1of the first portion of the window54and the radial width of the fitting portion61therebetween have the difference, thereby the first portion of the window54and the fitting portion61therebetween define a gap.

In an actual structure, a center axis of the component5(pipe case52) is displaced in general from a center axis of the center cylinder42within a manufacturing tolerance, for example. In the present structure show inFIGS. 8,9, the gap between the first portion of the window54and the fitting portion61is configured to absorb and relax stress caused by the displacement of the center axis of the component from the center axis of the center cylinder42.

On the other hand, when the cap9is detached from the housing7, the second portion of the window54having the second width W2is fitted with the fitting portion61as shown inFIG. 10. Therefore, when the cap9is detached from the housing7; the fitting portion61of the connection member6and the plate53of the component5are firmly connected to each other in the second portion of the window54having the second width W2. Thus, the component5can be further firmly connected to the cap9by the connection member6, and consequently the component5can be securely detached from the housing7when the cap9is detached from the housing7.

InFIGS. 2 and 4, a drain bolt10as a valve is provided for draining water, which is separated from fuel and stored in the sediment reservoir73. Further, a level switch11is provided for detecting that a level of water stored in the sediment reservoir73reaches a predetermined level. The level switch11may cause a warning signal when the level of water stored in the sediment reservoir73reaches the predetermined level. An indicator107may be activated according to the warning signal caused by the level switch11. For example, the indicator may be lit so as to enable recognition of the fact that the level of water stored in the sediment reservoir73reaches the predetermined level. The drain bolt10and the level switch11are mounted on the cap9. Thus, the drain bolt10and the level switch11can be easily mounted and removed together with the component5independently of the filter element41.

Hereinbefore, the fuel filter device1according to the first embodiment includes the filter element41formed from the filter material configured to capture a foreign substance in the fuel101A. The fuel filter device1further includes the component5having a predetermined function. The fuel filter device1further includes the case including the housing7and the cap9and accommodating the filter element41and the component5. The cap9as the lower case is formed in a manner of being attached to and detached from the housing7at the side of the bottom74of the housing7. The component5is provided in the passage44, which is for leading fuel. The passage extends through the filter element in the attachment and detachment directions Z of the cap9. The component5is configured to be loadable into and removable from the housing7, as the cap9is attached to and detached from the housing7.

Thus, in the present structure, the metal ion capturing material51and the like can be easily loaded and removed together with the component5independently from the filter element41.

That is, the fuel filter device has a structure, in which the component can be easily loaded and removed independently of the filter element,

Second Embodiment

In the first embodiment, the drain bolt10and the level switch11are mounted on the cap9. Alternatively, as shown inFIG. 11, a cap9A, on which the drain bolt10and the level switch11are not mounted, may be used instead of the cap9. Thus, the cap9A is connected to a component5A by using a connection member6A in place of the connection member6. In the connection member6A, a fitting portion61is added in a position of the level switch11shown inFIG. 2, and ring-shaped reinforcement plates64A to66A are provided in place of the semi-ring-shaped reinforcement plates64to66. In the component5A being provided in place of the component5, the window54is added in a position corresponding to the added fitting portion61. Even in the second embodiment, the same advantages as those described above can be obtained.

In the examples, the component5or5A is connected to the connection member6or6A by using the fitting portions61of the connection member6or6A respectively. Alternatively, the component5or5A and the connection member6or6A may be integrally structured respectively. Specifically, the plate53of the component5and the fitting portions61of the connection member6may be integrally formed from resin. That is, the pipe case52and the plate53of the component5and the fitting portions61and the reinforcement plates63to66of the connection member6may be integrally formed from resin.

In the examples, the component5or5A incorporates the metal ion capturing material51and is configured to capture metal ions in the fuel101A. The structure of the fuel filter device is not limited to the above structure incorporating the metal ion capturing material51. For example, the component5B may include an auxiliary filter material51B having a pore size, which is larger than a pore size of the filter material41, and configured to capture of some particulate matters. More specifically, the auxiliary filter material51B is configured to capture other particulate matters having a diameter larger than a diameter of the particulate matters that can be captured by the filter material41. That is, the auxiliary filter material51B being rough compared with the filter material41can be incorporated in the component5B as shown inFIG. 12. Specifically, the component5B includes the auxiliary filter material51B, a mesh55that encloses the auxiliary filter material51B, a pipe-shaped pipe case52that holds the mesh55enclosing the auxiliary filter material51B, and the plate53. The pipe case52and the plate53are integrally formed from resin.

In the present structure of the component5B, the component5B is configured to capture particulate matters having a diameter larger than a diameter of particulate matters that can be captured by the filter material41, in place of the function of capturing metal ions in the fuel101A. That is, the component5B has the auxiliary filter material51B that assists a capture function of the filter material41of capturing a foreign substance in the fuel101A. Thus, the auxiliary filter material51B and the like can be easily loaded and removed together with the component5B independently of the filter material41.

The number of the windows54and the number of the fitting portions61are not limited to the numbers described in the above embodiments, and can be arbitrary determined.

In the above embodiments, the fitting portion61has the end provided with the claw62, and the claw62is configured to be hooked to the second portion when the lower case9is rotated in the direction R2in the condition where the fitting portion61is inserted into the first portion. The lower case9is configured to be screwed in the first direction R1when the lower case9is attached to the housing7, and the lower case9is configured to be screwed in the second direction R2when the lower case9is detached from the housing7. The fitting portion61has the end provided with the claw62, and the fitting portion61is configured to be hooked to the second portion when the lower case9is rotated in the second direction R2. In the present condition, the component5,5A is configured to be pulled from the housing7together with the lower case9in the axial direction of the passage44by rotating the lower case9relative to the housing7in the second direction to detach the lower case9from the housing7. Therefore, the component5,5A can be easily pulled out of the housing7together with the lower case9. The passage44may extend through the filter element41in the axial direction.

In the above embodiments, the housing7has the inlet port2, which is configured to lead fuel into the housing7, and the outlet port3configured to lead fuel out of the housing7. The filter element41is configured to circumferentially surround the outer circumferential periphery of the component5,5A when the component5,5A is accommodated in the passage44. The inlet port2, the passage44, the filter element41, and the outlet port3are configured to lead fuel in order. The order of fuel flow may be arbitrary determined.

The above structures of the embodiments can be combined as appropriate. Various modifications and alternations may be diversely made to the above embodiments without departing from the spirit of the present invention.