Fuel filter

Abstract

To further improve the foreign substance capturing performance of a fuel filter including a filter medium layer having a small pore size.SOLUTION: One embodiment provides a fuel filter that is disposed in a fuel supply device for capturing foreign substances in fuel and comprises a plurality of laminated filter medium layers 31, 32, 33, 34, 35 having different average pore sizes. The thickness of the filter medium layer 34 having the smallest average pore size is greater than the thickness of at least one of the other filter medium layers 31, 32, 33, 35. In some embodiments, the thickness of the filter medium layer 34 having the smallest average pore size is greater than the thickness of the filter medium layer 33 disposed immediately upstream of the filter medium layer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in the present application relates to a fuel filter disposed in a fuel supply system. [Background technology]

[0002] Fuel supplied to fuel-consuming devices such as automobile engines is usually filtered out of foreign matter by a fuel filter located somewhere along the fuel supply path. For example, the fuel filter disclosed in Japanese Patent Laid-Open Publication No. 2008-168194 is located inside the automobile fuel tank and attached to the intake port of the fuel pump. This fuel filter has a multi-layer structure with multiple filter media layers stacked one on top of the other, and the pore size of each filter media layer is appropriately changed from the upstream side to the downstream side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-168194 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, the smaller the pore size of the filter layer, the faster it becomes clogged. Therefore, fuel filters including a filter layer with a small pore size, such as the fuel filter disclosed in the above publication, are likely to have a problem of not being able to sufficiently capture foreign matter before becoming clogged. Therefore, it is desirable to further improve the foreign matter capturing performance of fuel filters including a filter layer with a small pore size. [Means for solving the problem]

[0005] One aspect of the present technology is a fuel filter that is placed in a fuel supply device and captures foreign matter in fuel, and includes a plurality of stacked filter layers with different average pore sizes, and the thickness of the filter layer with the smallest average pore size is greater than the thickness of at least one of the other filter layers. By thickening the filter layer with the smallest average pore size in this way, the time until the filter layer becomes clogged is extended, and the amount of foreign matter captured by the fuel filter can be increased.

[0006] In some embodiments, the average pore size of the filter media layers decreases from the upstream side to the filter media layer with the smallest average pore size, thereby allowing various sizes of foreign matter to be captured by filter media layers with appropriate average pore sizes, thereby extending the time until the fuel filter becomes clogged.

[0007] In some embodiments, the fuel filter has a filter media layer having the smallest average pore size that is thicker than the filter media layer immediately upstream of the smallest average pore size, allowing the filter media layer immediately upstream of the smallest average pore size to efficiently capture foreign matter for a long period of time before the smallest average pore size layer becomes clogged. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a fuel filter according to an embodiment connected to a fuel pump; [Figure 2] 1 is a schematic diagram showing a filter medium configuration of a fuel filter according to one embodiment. FIG. [Figure 3] FIG. 4 is a schematic diagram showing a filter medium configuration of a fuel filter according to a comparative example. [Figure 4] FIG. 1 is a diagram showing a method for measuring pressure loss, which is an index of foreign matter capturing performance. [Figure 5] 4 is a graph showing the measurement results of pressure loss in each filter medium layer for the filter medium configurations of FIGS. 2 and 3. DETAILED DESCRIPTION OF THE INVENTION

[0009] Various embodiments will be described below with reference to the drawings.

[0010] [Fuel filter] In one embodiment, a fuel filter 10 shown in FIG. 1 is a component of a filter device 1 that is disposed in a fuel tank 5 of an automobile equipped with an engine or a fuel cell and is attached to the intake port of a fuel pump 3. The fuel pump 3 draws fuel from the fuel tank 5 through the fuel filter 10, thereby supplying clean fuel from which foreign matter has been removed to the engine. In another embodiment, the fuel filter 10 may be a fuel filter for various fuel-consuming devices, such as automobiles, motorcycles, ships, aircraft, and generators, in addition to automobiles. The fuel may be a liquid fuel, such as a petroleum-based fuel such as gasoline or diesel, an alcohol fuel, a biofuel, or a plant-based fuel. In another embodiment, a gaseous fuel such as hydrogen fuel may be used.

[0011] In one embodiment, the fuel filter 10 is bag-shaped, and its interior is connected to the fuel pump 3. Fuel in the fuel tank 5 is drawn into the fuel pump 3 through the interior of the fuel filter 10. The bag-shaped fuel filter 10 may be, for example, a flat bag-like shape. In one embodiment, it may be formed by welding or adhering an upper filter medium 11 and a lower filter medium 12 to each other at their peripheral edges 13. In another embodiment, the fuel filter 10 may be formed into a flat bag-like shape by folding a single filter medium in half and welding or adhering their peripheral edges. In yet another embodiment, the fuel filter 10 may be cylindrical, spherical, or any other bag-like shape instead of a flat shape, or may be any shape other than a bag-like shape, such as a flat shape.

[0012] [Inner frame member] An inner rib member 20 can be inserted into the bag-shaped fuel filter 10. The inner rib member 20 maintains the gap between the upper filter medium 11 and the lower filter medium 12 to prevent the fuel filter 10 from collapsing due to the negative pressure generated inside the fuel filter 10 by the suction of the fuel pump 3. In another embodiment, the inner rib member 20 itself can be formed from thick, hard filter paper to further filter the fuel that flows in through the fuel filter 10. In this case, the inner rib member 20 can be made, for example, corrugated, to have high rigidity and be less likely to deform.

[0013] [Connection to fuel pump] The filter device 1 includes a connecting member 40 made of resin, and the fuel filter 10 is connected to the fuel pump 3 via this connecting member 40. Specifically, by connecting an opening formed in the upper filter medium 11 of the fuel filter 10 to the intake port of the fuel pump 3, the interior of the filter device 1 is connected to the fuel pump 3 via a communication passage 41 in the connecting member 40.

[0014] [Filter layer] As shown in FIG. 2, the upper filter medium 11 and the lower filter medium 12 can each be formed by stacking multiple (five in the figure) filter medium layers 31, 32, 33, 34, and 35. Each filter medium layer is typically a nonwoven fabric, but in another embodiment, they can be formed from a filter medium other than a nonwoven fabric. The most upstream (dirty side) filter medium layer 31 and the most downstream (clean side) filter medium layer 35 can be made of a nonwoven fabric that is slightly stiffer than the intermediate filter medium layers 32, 33, and 34. This allows the most upstream and most downstream filter medium layers to function not only as foreign matter capture layers but also as protective layers, preventing the soft nonwoven fabrics of the intermediate filter medium layers 32, 33, and 34 from fraying due to vibration or other factors and preventing loose fibers from flowing downstream with the fuel. In another embodiment, only one of the most upstream filter medium layer 31 and the most downstream filter medium layer 35 can be a protective layer, or neither can be a protective layer. In another embodiment, the number of filter media layers constituting the fuel filter 10 in each of the upper filter media 11 and the lower filter media 12 may be four or less, or six or more.

[0015] [Average pore size of filter layer] The intermediate filter media layers 32, 33, and 34, which are not protective layers, can be configured so that their average pore sizes decrease sequentially from the upstream side to the downstream side (d2>d3>d4). This allows the intermediate filter media layers 32, 33, and 34 to capture larger foreign matter as the fuel passes through the upper filter media 11 and the lower filter media 12. The most upstream filter media layer 31 and the most downstream filter media layer 35, which serve as protective layers, can both have average pore sizes larger than all of the intermediate filter media layers 32, 33, and 34 (d1, d5>d2).

[0016] [Thickness of filter layer] As shown in Figure 2, the thicknesses of the filter media layers 31, 32, 33, 34, and 35 are such that the fourth filter media layer 34, which has the smallest average pore size, is thicker than the immediately upstream third filter media layer 33. In particular, in the embodiment of Figure 2, the fourth filter media layer 34 is thicker than all of the other filter media layers 31, 32, 33, and 35.

[0017] The graph in Figure 5 evaluates the pressure drop of each filter layer after a filtration test for the filter media configuration of the embodiment in Figure 2 and the filter media configuration of the comparative example in Figure 3. In the comparative example in Figure 3, the fourth filter media layer 134, which has the smallest average pore size, has the smallest thickness. The numbers on the horizontal axis of the graph represent the filter media layer numbers counted from the upstream side. The pressure drop of the filter media layer on the vertical axis is an indicator of the amount of foreign matter captured. Specifically, as shown in Figure 4, after a filtration test, the fuel filter 10 was separated into individual filter media layers 31, 32, 33, 34, and 35 at the point where clogging occurred, and air was drawn at a constant flow rate through each filter media layer using an air pump 50. The more foreign matter clogging the filter media layer, the greater the negative pressure (pressure drop) that appeared downstream of the filter media layer.

[0018] Comparing the two results shown in Figure 5 obtained using this method, the filter material configuration of Figure 2, in which the fourth filter material layer 34 is thicker, shows that the amount of foreign matter captured by the third filter material layer 33 and the fourth filter material layer 34 is particularly increased. This is thought to be because the increased thickness of the fourth filter material layer 34 causes the foreign matter captured by the fourth filter material layer 34 to disperse in the thickness direction, extending the time until clogging occurs. The reason why not only the fourth filter material layer 34 but also the third filter material layer 33 increases is thought to be because the time until the fourth filter material layer 34 becomes clogged is extended, allowing the third filter material layer 33 to continue capturing foreign matter during that time.

[0019] 3, the fourth filter layer 134 has the smallest thickness and pore size, so trapped foreign matter cannot be dispersed and clogging occurs first. At this time, the fuel filter 10 reaches the end of its product life, even though the second and third filter layers 132 and 133 still have the capacity to capture foreign matter.

[0020] From the above, it can be said that the filter media configuration of Fig. 2 makes the most of the power of the second filter media layer and the third filter media layer, improving the foreign matter capture performance of the fuel filter 10 as a whole. In fact, when the amount of foreign matter captured by the entire fuel filter 10 was measured, the amount of foreign matter captured by the filter media configuration of the embodiment of Fig. 2 was approximately 1.3 times greater than that of the filter media configuration of the comparative example of Fig. 3. Therefore, with the filter media configuration of Fig. 2, for example, the area of ​​the filter media can be reduced without reducing the capture amount, allowing the fuel filter 10 to be made smaller.

[0021] [Other embodiments] 2, the fourth filter layer 34 has the largest thickness. However, in another embodiment, simply making the filter layer with the smallest average pore size thicker than at least one of the other filter layers can extend the time until the filter layer with the smallest average pore size becomes clogged, thereby increasing the amount of foreign matter captured by the fuel filter. Also, in another embodiment, making the filter layer with the smallest average pore size thicker than the filter layer immediately upstream of that filter layer can enable the filter layer immediately upstream of that filter layer to efficiently capture foreign matter for a long period of time until the filter layer with the smallest average pore size becomes clogged.

[0022] Although various embodiments have been described above, the present disclosure is not limited to these embodiments, and various other modifications, substitutions, improvements, and the like are possible for those skilled in the art. [Explanation of symbols]

[0023] 1. Filter device 3. Fuel pump 5 fuel tank 10 Fuel filter 11 Upper filter medium 12 Lower filter medium 20 Inner bone member 31~35 Filter media layer 40 Connecting member 50 Air Pump

Claims

1. A fuel filter disposed in a fuel supply system to capture foreign matter in fuel, It has multiple filter media layers with different average pore sizes stacked together. A fuel filter in which the thickness of the filter media layer having the smallest average pore size is greater than the thickness of at least one other filter media layer.

2. 2. The fuel filter of claim 1, A fuel filter in which the average pore size of the filter media layers gradually decreases from the upstream side to the filter media layer with the smallest average pore size.

3. 3. The fuel filter of claim 1 or 2, A fuel filter in which the thickness of the filter layer having the smallest average pore size is greater than the thickness of the filter layer located immediately upstream of that filter layer.

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