JP2005133641A - Fuel filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amount of air or the like contained in fuel as compared with the conventional cases. <P>SOLUTION: A fuel filter 70 is equipped with a case 20 having a cylindrical wall 18 extending upward from a peripheral edge of a bottom wall 16 and a filter element 22 arranged in the case 20. An unfiltered fuel receiving chamber C is formed between the outer peripheral surface and lower end surface of the filter element 22 and the cylindrical wall 18 and bottom wall 16 of the case 20. The inlet 30 of the unfiltered fuel and the outlet 32 of filtered fuel are provided to the upper end of the case 20. The lower end of the filter element 22 is provided with a bottom 72 extending outward in a radial direction from the lower end and a cylindrical weir 74 extending upward from the peripheral edge of a bottom 72 with an annular space with respect to the lower end outer peripheral surface of the filter element 22. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a fuel filter, and more particularly to a fuel filter applied to a common rail fuel injection system for a vehicle engine.

In recent years, harmful substances such as particulate matter (PM) and nitrogen oxides (NOx) contained in the exhaust smoke of diesel engines mounted on vehicles such as trucks have become a social problem, causing global warming phenomenon. Environmental issues are important themes that must be solved on a global scale. Against this background, regulations on exhaust gas from vehicle diesel engines are becoming more stringent, and there is an urgent need to develop new technologies for purifying exhaust gas.

In such a technical background, the common rail fuel injection system has attracted attention as a leading technology for purifying exhaust gas of a vehicular diesel engine and has already been put into practical use. Unlike a conventional fuel injection system in which fuel is injected into a cylinder through a nozzle by a fuel injection pump, the common rail fuel injection system stores fuel in a high pressure state in the common rail before injection, Is a system that injects the high-pressure fuel stored in the cylinder into the cylinder by controlling the injector at an appropriate timing, enabling high-pressure injection from the low-speed range, greatly reducing the generation of black smoke in the low-speed range. Moreover, NOx reduction, noise suppression, fuel consumption improvement, etc. are improved.

As the adoption of such a common rail fuel injection system has progressed, an undesirable phenomenon has occurred in which a relatively large amount of air or fuel vapor is contained in the fuel. Hereinafter, this problem will be described more specifically with reference to FIG. Reference numeral 2 denotes a common rail, and the common rail 2 and the fuel tank 4 are connected by a fuel supply pipe 8 via a fuel pump P and a fuel filter 6. The common rail 2 and the fuel tank 4 are also connected by a fuel return pipe 10. Four injectors 12 are connected to the common rail 2 via fuel supply pipes 14.

The fuel filter 6 includes a case 20 having a substantially hemispherical bottom wall 16, a cylindrical wall 18 extending upward from the periphery of the bottom wall 16, and a filter element 22 disposed in the case 20. Yes. An upper wall 24 is provided at the upper end opening of the case 20. The substantially cylindrical filter element 22 is supported by a lower support plate 26 and an upper support plate 28, each having a substantially disc shape. The lower end of the filter element 22 is supported while being closed by a lower support plate 26, and the upper end of the filter element 22 is supported by an upper support plate 28. A through hole 29 is formed at the center of the upper support plate 28. The filter element 22 is mounted in the case 20 by being fixed in a state where the upper support plate 28 is sealed to the lower surface of the upper wall 24 of the case 20. Note that a fuel filter having a configuration such as the fuel filter 6 is known, for example, from Patent Document 1.

Between the outer peripheral surface and lower end surface of the filter element 22 (the lower surface of the lower support plate 26) and the cylindrical wall 18 and the bottom wall 16 of the case 20, there is an unfiltered fuel receiving chamber C for receiving unfiltered fuel. Is formed. An unfiltered fuel inlet 30 to the unfiltered fuel receiving chamber C is provided at the peripheral edge of the upper wall 24 that is the upper end of the case 20. An outlet 32 for filtered fuel that has passed through the filter element 22 is provided at the center of the upper wall 24 that is the upper end of the case 20. The outlet 32 of the upper wall 24 is aligned with a through hole 29 formed in the upper support plate 28 of the filter element 22. An unfiltered fuel inlet 30 formed on the upper wall 24 of the case 20 is connected to the fuel tank 4 via the fuel supply pipe 8. The filtered fuel outlet 32 formed on the upper wall 24 of the case 20 is connected to the suction side of the fuel pump P via the fuel supply pipe 8.

When the fuel pump P is driven, the unfiltered fuel (light oil) in the fuel tank 4 is surrounded by a peripheral region in the case 20 via the fuel supply pipe 8 and the unfiltered fuel inlet 30 by the suction force of the fuel pump P. In the unfiltered fuel receiving chamber C. The fuel that has flowed into the unfiltered fuel receiving chamber C is filtered while passing through the filter element 22, and the filtered fuel passes through the outlet 32 and the fuel supply pipe 8 located upstream of the fuel pump P, and the fuel pump P. And is supplied to the common rail 2 at a high pressure through the fuel supply pipe 8 located on the downstream side of the fuel pump P. The high-pressure fuel stored in the common rail 2 is injected into the combustion chamber of the diesel engine at an appropriate timing by controlling the injector 12.

In a fuel filter used in a common rail fuel injection system of a diesel engine mounted on a vehicle, after a new fuel filter is installed at the time of shipment from the factory or after replacement with a new filter element at a repair shop, a predetermined air bleeding operation is performed. After the vehicle has traveled for the first time, as described above, for some time after the vehicle travels, an undesirable phenomenon is observed in which a relatively large amount of air or fuel vapor is contained in the fuel. Then, in order to confirm the reason why such a phenomenon occurs, as a result of intensive studies and experiments conducted by the present inventors, the following facts were confirmed.

Hereinafter, this fact will be described with reference to FIG. When the fuel pump 6 is driven after the fuel filter 6 is provided in the illustrated fuel supply path with a dry new filter element 22 not touching the fuel at all, the air and fuel are unfiltered fuel in the case 20. It is made to flow into the receiving room C. Fuel and air are drawn from the outlet 32 through the filter element 22. The fuel that has flowed into the unfiltered fuel receiving chamber C gradually accumulates from the bottom of the bottom wall 16, which is the lower part of the unfiltered fuel receiving chamber C, and the liquid level L is the lower end of the filter element 22, that is, Ascending to a position slightly higher than the lower surface of the lower support plate 26. The fuel is sucked from the outer peripheral surface completely immersed in the fuel below the liquid level L at the lower end portion of the filter element 22 and is raised in the filter element 22, and is supplied from the outlet 32 to the fuel pump P as filtered fuel. Sucked.

However, in the unfiltered fuel receiving chamber C outside the filter element 22, the liquid level of the unfiltered fuel does not rise above the liquid level L. The reason for this is as follows. That is, in the initial dry state, the filter element 22 has low passage resistance and thus allows air to pass through easily. However, if the filter element 22 gets wet from the outer peripheral surface side due to the inflow of fuel, the surface tension of the fuel, the filter element 22 Due to the mesh or the like, the passage resistance increases rapidly. Air and fuel pass through the filter element 22 due to the difference between the inlet pressure P0 in the unfiltered fuel receiving chamber C and the outlet pressure P1 in the filter element 22, but the outer periphery of the filter element 22 above the liquid level L. Since the passage resistance of the surface increases, air is not sucked. As a result, air is trapped in the unfiltered fuel receiving chamber C above the liquid level L, and only fuel is substantially sucked from the outer peripheral surface of the filter element 22 that is completely immersed in the fuel below the liquid level L. . As a result, the liquid level L is maintained at a position balanced with the inlet pressure P0. During this period, the fuel system including the inside of the common rail 2 and the injector 12 and the like on the downstream side of the fuel pump P is vented in a predetermined manner, and the vehicle can travel.

In the fuel filter used in the common rail type fuel injection system, the mesh of the filter element 22 is relatively fine as an average of 100 μm, and unnecessary work by the fuel pump P is eliminated as much as possible in order to secure the necessary horsepower of the engine. Due to the fact that the suction force by the fuel pump P is limited due to the fact that it has to be done, the liquid level L can be raised at least for a while after the fuel is first passed through the filter element 22. Can not. As a result, when the vehicle is driven in such a state, not only the effective filtration area on the outer peripheral surface of the filter element 22 is reduced, but also the liquid surface is inclined (see the two-dot chain line L1 in FIG. 3). ), The outer peripheral surface of the lower end portion of the filter element 22 is exposed to the outside, and a large amount of air in the unfiltered fuel receiving chamber C is sucked, or the air pressure drops at high altitude, so that the fuel passes through the filter element 22. Sometimes fuel vapor is generated.

Note that the above-described problems are common even when other types of fuel filters are used. FIG. 4 schematically shows the configuration of a common rail fuel injection system in which another form of fuel filter 40 is used. In FIG. 4, substantially the same parts as those in FIG. 3 are denoted by the same reference numerals. A fuel filter 40 shown in FIG. 4 includes a case 46 having a substantially hemispherical bottom wall 42, a cylindrical wall 44 extending upward from the periphery of the bottom wall 42, and a filter element disposed in the case 46. 48. An upper wall 50 is provided at the upper end opening of the case 48. The filter element 48 having a substantially cylindrical shape is supported by a lower support plate 52 and an upper support plate 54 that are substantially disk-shaped. The lower end of the filter element 48 is supported while being closed by the lower support plate 52, and the upper end of the filter element 48 is supported by the upper support plate 54. A through hole 56 is formed at the center of the upper support plate 54. The filter element 48 is mounted in the case 46 by being fixed with the upper support plate 54 sealed to the lower surface of the upper wall 50 of the case 46.

An unfiltered fuel receiving chamber C for receiving unfiltered fuel is formed inside the inner peripheral surface of the filter element 48. An unfiltered fuel inlet 58 to the unfiltered fuel receiving chamber C is provided at the center of the upper wall 50 that is the upper end of the case 46. The inlet 58 of the upper wall 50 is aligned with a through hole 56 formed in the upper support plate 54 of the filter element 48. Between the outer peripheral surface and lower end surface of the filter element 48 (the lower surface of the lower support plate 52) and the cylindrical wall 44 and the bottom wall 42 of the case 46, the filtered fuel for receiving the filtered fuel that has passed through the filter element 48. A fuel receiving chamber 60 is formed. An outlet 62 of the filtered fuel that has passed through the filter element 48 is provided at the peripheral edge of the upper wall 50 that is the upper end of the case 46. An unfiltered fuel inlet 58 formed in the upper wall 50 of the case 46 is connected to the fuel tank 4 via the fuel supply pipe 8. The filtered fuel outlet 62 formed on the upper wall 24 of the case 46 is connected to the suction side of the fuel pump P via the fuel supply pipe 8.

When the fuel pump P is driven, unfiltered fuel in the fuel tank 4 is present in the central region in the case 46 via the fuel supply pipe 8 and the unfiltered fuel inlet 58 by the suction force of the fuel pump P. It flows into the unfiltered fuel receiving chamber C. The fuel that has flowed into the unfiltered fuel receiving chamber C is filtered while passing through the filter element 48 and flowing into the filtered fuel receiving chamber 60. The filtered fuel that has flowed into the filtered fuel receiving chamber 60 is sucked by the fuel pump P through the outlet 62 and the fuel supply pipe 8 positioned upstream of the fuel pump P, and the fuel positioned downstream of the fuel pump P. A high pressure is supplied to the common rail 2 through the supply pipe 8. The high-pressure fuel stored in the common rail 2 is injected into the combustion chamber of the diesel engine at an appropriate timing by controlling the injector 12.

After the fuel filter 40 is provided in the fuel supply path shown in FIG. 4 with a dry new filter element 48 that does not touch the fuel at all, when the fuel pump P is driven, air and fuel are removed from the case 46. It flows into the unfiltered fuel receiving chamber C. Fuel and air are passed through the filter element 48 into the filtered fuel receiving chamber 60. The fuel that has flowed into the filtered fuel receiving chamber 60 gradually accumulates from the bottom of the bottom wall 42, which is the lower part of the filtered fuel receiving chamber 60, and the liquid level reaches the outlet 62 and enters the fuel pump P. Sucked. On the other hand, the liquid level L of the unfiltered fuel that has flowed into the unfiltered fuel receiving chamber C rises to a position slightly higher than the lower end of the filter element 48, that is, the upper surface of the lower support plate 52, but is the same as described above. For the reason, the liquid level of the unfiltered fuel in the unfiltered fuel receiving chamber C does not rise above the liquid level L due to the trapped air. The fuel is sucked to the filtered fuel receiving chamber 60 side from the inner peripheral surface completely immersed in the fuel below the liquid level L at the lower end portion of the filter element 48. As a result, the liquid level L is maintained at a position balanced with the inlet pressure P0. During this period, the fuel system including the inside of the common rail 2 and the injector 12 and the like on the downstream side of the fuel pump P is vented in a predetermined manner, and the vehicle can travel. When the vehicle is driven in such a state, not only the effective filtration area on the inner peripheral surface of the filter element 48 is reduced, but also the liquid surface is inclined (see the two-dot chain line L1 in FIG. 4). When the inner peripheral surface of the lower end portion of the filter element 48 is exposed to the outside and a large amount of air in the unfiltered fuel receiving chamber C is sucked or the air pressure drops at high altitude, the fuel passes through the filter element 48. In other words, fuel vapor is generated.
Japanese Patent No. 3177821

The object of the present invention is to reduce the air and fuel vapor contained in the fuel even when the vehicle is run after a new fuel filter is installed at the time of shipment from the factory or after replacement with a new filter element at a repair shop. It is to provide a novel fuel filter that makes it possible to reduce the amount than before.

According to one aspect of the present invention, there is provided a case having a bottom wall and a cylindrical wall extending upward from the peripheral edge of the bottom wall, and a filter element disposed in the case and closed at the lower end, the outer periphery of the filter element An unfiltered fuel receiving chamber for receiving unfiltered fuel is formed between the surface and the lower end surface and the cylindrical wall and bottom wall of the case, and an unfiltered fuel receiving chamber for receiving the unfiltered fuel receiving chamber is formed at the upper end of the case. In a fuel filter provided with an inlet for filtered fuel and an outlet for filtered fuel that has passed through the filter element, a lower end of the filter element has a bottom extending radially outward from the lower end, and a peripheral edge of the bottom And a cylindrical weir extending upward to a predetermined height with an annular gap with respect to the outer peripheral surface of the lower end portion of the filter element.
According to another aspect of the present invention, a case having a bottom wall and a cylindrical wall extending upward from the periphery of the bottom wall, and a cylindrical filter element disposed in the case and closed at the lower end, An unfiltered fuel receiving chamber for receiving unfiltered fuel is formed inside the inner peripheral surface of the filter element, and a filter is provided between the outer peripheral surface and lower end surface of the filter element and the cylindrical wall and bottom wall of the case. A filtered fuel receiving chamber for receiving the filtered fuel that has passed through the element is formed, and an upper portion of the case is provided with an unfiltered fuel inlet to the unfiltered fuel receiving chamber and an outlet for the filtered fuel. In the fuel filter, a bottom and a cylindrical weir that extends upward from the bottom to a predetermined height with an annular gap from the bottom to the inner peripheral surface of the lower end of the filter element are provided inside the lower end of the filter element. Are, fuel filter, it is provided, characterized in that.
The predetermined height of the cylindrical weir is the entire circumference of the outer peripheral surface of the lower end portion of the filter element or the lower end of the filter element when the case including the filter element is inclined to the maximum inclination angle in use. It is preferable that the entire circumference of the inner peripheral surface of the portion is defined below the liquid surface so as not to be exposed to the outside.

Hereinafter, preferred embodiments of a fuel filter according to the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of a common rail type fuel injection system of a diesel engine using an embodiment of a fuel filter 70 according to the present invention. Components substantially the same as those in FIG. . The fuel filter 70 is an improvement of the fuel filter 6 shown in FIG. 3, and includes a bottom end of the filter element 22 that extends radially outward from the bottom end, and a bottom end of the filter element 22 from the periphery of the bottom 72. A cylindrical weir 74 that extends upward to a predetermined height with an annular gap with respect to the outer peripheral surface of the part is provided. In the embodiment, the bottom 72 and the weir 74 are formed integrally with the lower support plate 26 of the filter element 22 having a column shape, in the embodiment, a substantially cylindrical shape. Accordingly, the bottom 72 has a disc shape, and the weir 74 has a cylindrical shape. An annular fuel reservoir 76 is formed by the outer peripheral surface at the lower end of the filter element 22, the bottom 72, and the cylindrical weir 74. The height of the weir 74 from the bottom 72 is substantially constant over the entire circumference. The other structure of the fuel filter 70 is substantially the same as that of the fuel filter 6 shown in FIG. 3, and further description is omitted.

After the fuel filter 70 is provided in the fuel supply path shown in FIG. 3 with a new dry filter element 22 that does not touch the fuel at all, when the fuel pump P is driven, air and fuel are not supplied to the case 20. It flows into the filtered fuel receiving chamber C. Fuel and air are drawn from the outlet 32 through the filter element 22. The fuel that has flowed into the unfiltered fuel receiving chamber C gradually accumulates from the bottom of the bottom wall 16, which is the lower part of the unfiltered fuel receiving chamber C, and the liquid level L is the upper end of the cylindrical weir 74. Reach the same plane. On the other hand, fuel also accumulates in the annular fuel reservoir 76, but the amount of fuel suction increases as the engine speed increases, and the volume of the fuel reservoir 76 is the lower end of the unfiltered fuel receiving chamber C. The fuel level in the unfiltered fuel receiving chamber C reaches the same surface as the upper end of the cylindrical weir 74 and is full. The amount of fuel flowing into the fuel reservoir 76 is larger than the fuel sucked from the fuel reservoir 76. As a result, the liquid level of the fuel in the fuel reservoir 76 reaches the same surface as the upper end of the cylindrical weir 74 and becomes full. Therefore, the fuel level L in the fuel reservoir 76 and the fuel level L in the unfiltered fuel receiving chamber C are maintained on the same plane as the upper end of the cylindrical weir 74.

The fuel is sucked from the outer peripheral surface completely immersed in the fuel below the liquid level L at the lower end portion of the filter element 22 and is raised in the filter element 22, and is supplied from the outlet 32 to the fuel pump P as filtered fuel. Sucked. The predetermined height from the bottom 72 to the upper end of the cylindrical weir 74, and thus the height from the lower end of the filter element 22 to the liquid level L, can be made higher than the height in the conventional fuel filter 6. is there. As a result, when the vehicle is driven in such a state, the effective filtration area on the outer peripheral surface of the filter element 22 is increased as compared with the conventional fuel filter 6 shown in FIG.

Further, when the case 20 having the filter element 22 is inclined to the maximum inclination angle during use, the predetermined height of the cylindrical weir 74 is the entire outer peripheral surface of the lower end portion of the filter element 22. By prescribing that the circumference is below the inclined liquid surface L1 and is not exposed to the outside, a large amount of air in the unfiltered fuel receiving chamber C is prevented from being sucked. Further, even when the atmospheric pressure drops at high altitude, the generation of fuel vapor when the fuel passes through the filter element 22 is prevented. Therefore, according to the fuel filter 70 of the present invention shown in FIG. 1, even when the vehicle is run after a new fuel filter is mounted at the time of factory shipment or after replacement with a new filter element at a repair shop, The amount of air and fuel vapor contained in the fuel can be reduced as compared with the conventional fuel filter 6 shown in FIG.

FIG. 2 is a schematic configuration diagram of a common rail type fuel injection system for a diesel engine using an embodiment of the fuel filter 80 according to the present invention. Components substantially the same as those in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted. . The fuel filter 80 is an improvement of the fuel filter 40 shown in FIG. 4, and has a cylindrical shape, in the embodiment, a cylindrical filter element 48 with a bottom, in the embodiment, below the filter element 48. A support plate 52 and a cylindrical weir 82 that extends upward to a predetermined height with an annular gap from the bottom lower support plate 52 as the bottom to the inner peripheral surface of the lower end portion of the filter element 48 are provided. The cylindrical weir 82 is fixed to the upper surface of the lower support plate 52 whose bottom in the axial direction is the bottom. An annular fuel reservoir 84 is formed by the inner peripheral surface at the lower end of the filter element 48 having a cylindrical shape, the lower support plate 52 as the bottom, and the cylindrical weir 82. The height of the weir 82 from the lower support plate 52 that is the bottom is substantially constant over the entire circumference. The other structure of the fuel filter 80 is substantially the same as that of the fuel filter 40 shown in FIG. 4, and further description is omitted.

After the fuel filter 80 is provided in the fuel supply path shown in FIG. 2 with a dry new filter element 48 that does not touch the fuel at all, when the fuel pump P is driven, air and fuel are removed from the case 46. It flows into the unfiltered fuel receiving chamber C. Fuel and air are passed through the filter element 48 into the filtered fuel receiving chamber 60. The fuel that has flowed into the filtered fuel receiving chamber 60 gradually accumulates from the bottom of the bottom wall 42, which is the lower part of the filtered fuel receiving chamber 60, and the liquid level reaches the outlet 62 and enters the fuel pump P. Sucked. On the other hand, a cup-shaped fuel reservoir 86 formed inside an annular fuel reservoir 84 installed at the bottom of the unfiltered fuel receiving chamber C, that is, the center region of the lower support plate 52 as a bottom, and a cylindrical shape The fuel gradually accumulates in the cup-shaped fuel reservoir 86 formed between the inner side of the weir 82 in the radial direction, and the liquid level L reaches the same surface as the upper end of the cylindrical weir 82. . The fuel also accumulates in the annular fuel reservoir 84, but the amount of fuel suction increases as the engine speed increases, and the volume of the annular fuel reservoir 84 is the same as that of the unfiltered fuel receiving chamber C. Due to the fact that the volume of the fuel in the cup-shaped fuel reservoir 86 is smaller than the entire volume of the lower end, the liquid level L of the fuel reaches the same plane as the upper end of the cylindrical weir 82 and is full, etc. The amount of fuel flowing into the annular fuel reservoir 84 is larger than the fuel sucked from the annular fuel reservoir 84 by the fuel pump P. As a result, the liquid level of the fuel in the annular fuel reservoir 84 reaches the same surface as the upper end of the cylindrical weir 74 and becomes full. Accordingly, the fuel level L in the annular fuel reservoir 84 and the fuel level L in the cup-shaped fuel reservoir 86 are maintained on the same plane as the upper end of the cylindrical weir 82. The

In the unfiltered fuel receiving chamber C, the fuel is sucked from the inner peripheral surface completely immersed in the fuel below the liquid level L at the lower end portion of the filter element 48, and the filtered fuel is received through the filter element 48. The fuel is introduced into the chamber 60 and sucked into the fuel pump P from the outlet 62 as filtered fuel. The predetermined height from the bottom lower support plate 52 to the upper end of the cylindrical weir 82, and hence the height from the lower end of the filter element 48 to the liquid level L, is higher than the height in the conventional fuel filter 40. Is possible. As a result, when the vehicle is driven in such a state, the effective filtration area on the inner peripheral surface of the filter element 48 is increased as compared with the conventional fuel filter 40 shown in FIG.

Further, when the case 46 provided with the filter element 48 is inclined to the maximum inclination angle during use, the predetermined height of the cylindrical weir 82 is the inner peripheral surface of the lower end portion of the filter element 48. By prescribing that the entire circumference exists below the inclined liquid surface L1 and is not exposed to the outside, a large amount of air in the unfiltered fuel receiving chamber C is prevented from being sucked. Further, even when the atmospheric pressure drops at high altitude, fuel vapor is prevented from being generated when the fuel passes through the filter element 48. Therefore, according to the fuel filter 80 of the present invention shown in FIG. 2, even when the vehicle is run after a new fuel filter is mounted at the time of factory shipment or after replacement with a new filter element at a repair shop, The amount of air and fuel vapor contained in the fuel can be reduced as compared with the conventional fuel filter 40 shown in FIG.

1 is a schematic configuration diagram of a diesel engine common rail fuel injection system using an embodiment of a fuel filter according to the present invention. The schematic block diagram of the common-rail type fuel injection system of the diesel engine which uses other embodiment of the fuel filter by this invention. The schematic block diagram of the common-rail type fuel injection system of the diesel engine which uses one form of the conventional fuel filter. The schematic block diagram of the common-rail type fuel injection system of the diesel engine which uses the other form of the conventional fuel filter.

Explanation of symbols

2: Common rail 4: Fuel tank 6, 40, 70, 80: Fuel filter 16, 42: Bottom wall 18, 44: Cylindrical wall 20, 46: Case 22, 48: Filter element 30, 58: Unfiltered fuel inlet 32, 62: Filtered fuel outlet
72: bottom 74, 82: cylindrical weir 76, 84: annular fuel reservoir L: fuel liquid level L1: fuel inclined liquid level C: unfiltered fuel receiving chamber P: fuel pump

Claims (3)

A case having a bottom wall and a cylindrical wall extending upward from the peripheral edge of the bottom wall, and a filter element disposed in the case and closed at the lower end, the outer peripheral surface and the lower end surface of the filter element, and the cylinder of the case An unfiltered fuel receiving chamber for receiving unfiltered fuel is formed between the shaped wall and the bottom wall, and an inlet of the unfiltered fuel to the unfiltered fuel receiving chamber and a filter element are provided at the upper end of the case. In the fuel filter provided with the outlet of the filtered fuel that has passed,
At the lower end of the filter element, a bottom that extends radially outward from the lower end, and a cylindrical shape that extends upward from the peripheral edge of the bottom to a predetermined height with an annular gap with respect to the outer peripheral surface of the lower end of the filter element Of weirs,
A fuel filter characterized by that. A case having a bottom wall and a cylindrical wall extending upward from the peripheral edge of the bottom wall, and a cylindrical filter element disposed in the case and closed at the lower end, inside the inner peripheral surface of the filter element An unfiltered fuel receiving chamber for receiving unfiltered fuel is formed, and the filtered fuel that has passed through the filter element is received between the outer peripheral surface and lower end surface of the filter element and the cylindrical wall and bottom wall of the case. In the fuel filter in which the filtered fuel receiving chamber is formed, and the upper end of the case is provided with an unfiltered fuel inlet to the unfiltered fuel receiving chamber and a filtered fuel outlet,
Inside the lower end of the filter element, a bottom and a cylindrical weir extending from the bottom to a predetermined height with an annular gap with respect to the inner peripheral surface of the lower end of the filter element are provided.
A fuel filter characterized by that. The predetermined height of the cylindrical weir is the entire circumference of the outer peripheral surface of the lower end portion of the filter element or the lower end of the filter element when the case including the filter element is inclined to the maximum inclination angle in use. 3. The fuel filter according to claim 1, wherein the entire circumference of the inner circumferential surface in the portion is defined to be present below the liquid surface and not exposed to the outside.

Images