JP2003299922A - Air cleaner element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air cleaner element capable of enhancing dust permeability (that is, reducing a permeation amount of dust being the amount of captured dust discharged from a filter medium by pulsating air streams) while keeping the dust and carbon capturing capacity of a density gradient type nonwoven fabric. <P>SOLUTION: The filter medium 1 of the air cleaner element is equipped with the first filter layer 3 comprising a nonwoven fabric and the second filter layer 4 provided on the downstream side of the first filter layer 3 and comprising a nonwoven fabric having meshes finer than those of the nonwoven fabric of the first filter layer 3. The first filter layer 3 is impregnated with oil and the second filter layer 4 has an oil repellency. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air cleaner element for an internal combustion engine of an automobile or the like. 2. Description of the Related Art As an air cleaner element for an internal combustion engine of an automobile or the like, there is known an air cleaner element in which a filter medium made of a density gradient type nonwoven fabric having a coarse layer and a dense layer is formed into a chrysanthemum flower shape and fixed by a frame. (For example, see Patent Document 1 and page 1). Filter media made of non-woven fabric of density gradient type
An appropriate density gradient is formed from the coarse layer to the dense layer according to the particle size distribution of the dust to be captured. The coarse layer on the inflow side of the outside air selectively captures mainly dust having a large particle diameter, while the dense layer on the outflow side of the outside air captures dust having a small particle diameter mainly composed of carbon. [Patent Document 1] JP-A-56-107950 [0004] If a filter medium made of a non-woven fabric of a density gradient type is used, any layer can be selectively captured by using a filter medium. Even in the layer, dust can be captured in a well-balanced manner, and an increase in the ventilation resistance of the filter medium can be suppressed as much as possible. An object of the present invention is to further improve the performance of an air cleaner element made of the above-mentioned density gradient nonwoven fabric while maintaining its performance. Specifically, the dust permeation performance is improved while maintaining the dust and carbon trapping performance of the density gradient nonwoven fabric (that is, the amount of trapped dust that is released from the filter medium due to the pulsation of the air flow is reduced. It is an object of the present invention to provide an air cleaner element which can be reduced. According to a first aspect of the present invention, there is provided a first filter layer comprising a non-woven fabric, and a non-woven fabric of the first filter layer provided downstream of the first filter layer. A second filter layer made of a nonwoven fabric having finer eyes than the first filter layer, wherein the first filter layer is impregnated with oil, and the second filter layer has a property of repelling oil. The above-mentioned problem is solved by the air cleaner element. According to the present invention, by impregnating the first filter layer with oil, it is possible to prevent the captured dust from being re-emitted from the first filter layer. Further, the first filter layer having an oil-repelling property allows the
The movement of the oil of the filter layer to the second filter layer is suppressed. For this reason, the amount of dust permeated, which is the amount of trapped dust released from the filter medium, can be reduced. [0008] The first filter layer is composed of a plurality of layers stacked so as to become coarser toward the upstream, and the thickness of the first filter layer is equal to the thickness of the second filter layer. It is desirable that it be thicker. According to the present invention, by forming the first filter layer into a plurality of layers, it is possible to secure the amount of dust trapped without increasing the airflow resistance. In addition, by making the first filter layer thicker than the second filter layer,
A relatively large amount of dust and carbon can be captured by the filter layer. An embodiment of an air cleaner element according to the present invention will be described below with reference to the drawings. An air cleaner element 10 shown in FIG.
Consists of a bent filter medium 1 and a plastic frame 2 formed in a rectangular shape and holding the filter medium 1. FIG.
As shown in (1), the filter medium 1 is insert-molded into the frame material 2 at the periphery thereof, and is fixed to the frame material 2. FIG. 2 shows the filter medium 1. The filter medium 1 is composed of an upstream first filter layer 3 made of a nonwoven fabric and a downstream second filter layer 4 made of a nonwoven fabric. The first filter layer 3 is coarsely formed, and the second filter layer 4
Are formed finer than the first filter layer 3. First
The filter layer 3 is impregnated with oil, and the second filter layer is not impregnated with oil. The dry second filter layer has an oil-repellent property. The thickness of the first filter layer 3 is larger than the thickness of the second filter layer 4. Also, the first filter layer 3
It is composed of a plurality of layers, for example, 2 to 4 layers, which are superimposed so as to become coarser toward the upstream of the air flow. The reason why the first filter layer 3 is made thicker than the second filter layer 4 is to capture a large amount of dust and carbon (ie, not to capture dust and carbon in a surface area like a filter paper, but to include a thickness). Large volume of dust and carbon are captured.) The reason why the first filter layer 3 is composed of a plurality of layers is to secure a trapped amount of dust and carbon without increasing airflow resistance. As a material of the first filter layer 3, a non-woven fabric is used. A nonwoven fabric is a fabric made by arranging or tangling synthetic fibers irregularly by means of a binder, heat and pressure, and sewing. The nonwoven fabric of the first filter layer 3 contains lipophilic fibers. PET (polyethylene terephthalate), polyester, polyamide, or the like can be used as the lipophilic fiber. The first filter layer 3 is impregnated with oil such as viscous oil. The oil impregnated in the first filter layer 3 oozes out on the upper surface of the first filter layer 3,
A state in which dust is easily captured is formed. That is, the first
After the dust is trapped in the oil on the surface of the filter layer 3, the oil further penetrates into the trapped dust, so that the next dust is trapped on the dust surface. The material of the second filter layer 4 is also a non-woven fabric. Oil-repellent fibers are added to the nonwoven fabric of the second filter layer 4. As the oil-repellent fiber, a fluorine fiber, a fiber coated with fluorine, or the like can be used. It is also conceivable to use fluorine as a binder. This oil-repellent fiber prevents the oil in the first filter layer 3 from moving to the second filter layer 4. By impregnating the first filter layer 3 with oil, re-emission of the captured dust from the first filter layer 3 can be suppressed. Further, the movement of the oil in the first filter layer 3 to the second filter layer 4 is suppressed by the second filter layer 4 having a property of repelling oil. Therefore, it is possible to reduce the amount of dust permeated, which is the amount of dust trapped by the pulsation of the air flow and released from the filter medium 1. The second filter layer 4 is formed more densely than the first filter layer 3. Specifically, for example, the fiber diameter of the second filter layer 4 is made smaller than the fiber diameter of the first filter layer 3, and the opening of the fiber including the binder of the second filter layer 4 is set to the first filter layer. It is made smaller than the aperture of the filter layer 3. In addition, the second filter layer 4 includes a plurality of layers, for example, 1 to 3 layers, which are superimposed so as to become coarser toward the upstream of the air flow. By adjusting the aperture, the fiber diameter, the amount of the binder, the thickness, the layer configuration, and the like of the second filter layer 4, the efficiency with which the filter medium captures dust and carbon can be adjusted. When the air cleaner element according to the present embodiment is used as an air cleaner element for a vehicle, the thickness of the first filter layer 3 is, for example, 0.4 to 1.0.
The thickness is set to 7 mm, and the thickness of the second filter layer 4 is set to, for example, 0.1 to 0.8 mm. The thickness of the entire filter medium is
In consideration of the degree of freedom of the layout, the thickness is set to be thinner than a conventional filter medium made of a density gradient type nonwoven fabric, for example, 1.0%.
It is set to about 1.5 mm. The thicknesses of the first filter layer 3 and the second filter layer 4 are determined to be optimal values in consideration of the amount of dust and carbon trapped, the dust and carbon trapping efficiency, and the oil blow-through property. First filter layer 3 and second filter layer 4
The bonding of the first filter layer 3 and the plurality of layers of the second filter layer 4 is performed by a needle punch in which a bonding surface is impregnated with a binder and the fibers are entangled with each other. In addition, a fusion fiber such as a low-melting fiber may be blended into the fibers of each layer and joined, welded, joined with an adhesive, or combined with each other. As shown in FIG. 1, in the present embodiment, the filter medium 1 is bent to increase the substantial area of the filter, but as shown in FIG. It may be used in a stretched state. On the other hand, FIG.
(B) has shown the example which bent the filter medium 1 and formed the panel type filter. Also, as shown in FIGS. 4 (a) and 4 (b), the filter medium 1 is formed into a cylindrical shape or a chrysanthemum flower shape, and air is allowed to flow from the inside to the outside or from the outside to the inside of the tube. The shape can be selected. FIG. 5 shows the performance of the filter medium of the present embodiment in comparison with a comparative example (conventional density gradient type filter medium). Here, it is assumed that the air cleaner element is incorporated in the intake path of the engine. FIG. 6 shows the structure of a filter medium of a comparative example. The filter medium 6 of the comparative example is composed of a first filter layer 7 made of a non-woven fabric of polyester fibers and a second filter layer 8 made of a non-woven fabric of polyester fibers. The first filter layer 7 is coarse and the second filter layer 8 is fine. The thickness of the first filter layer 7 is set to about 2 mm, and the thickness of the second filter layer 8 is set to about 0.5 mm. Neither the first filter layer 7 nor the second filter layer 8 is impregnated with oil. The performance of the filter medium of this embodiment will be described for each item shown in FIG. <Ventilation Resistance> According to the present embodiment, the thickness of the filter medium can be reduced, so that, for example, the filter medium 1 can be easily bent in a zigzag manner, and a large filtration area can be obtained. Therefore, the airflow resistance can be reduced as compared with the comparative example. It is considered that the ventilation resistance of the filter medium of the present embodiment is not much different from the ventilation resistance of the comparative example. <Dust Capture Amount> According to the present embodiment, after the dust on the oil on the surface of the first filter layer 3 is captured,
By further penetrating oil into the captured dust,
An action of capturing the next dust (so-called dust cake layer) occurs on the surface of the dust. The effect of trapping in the dust cake layer is combined with the effect of trapping in the volume unique to the nonwoven fabric, so that the amount of dust trapped is improved. <Dust Permeation Amount> By changing the first filter layer 3 from a dry type to a wet type, re-release of captured dust is suppressed, and the dust permeation amount is reduced. The amount of dust permeation is
The amount of trapped dust permeates downstream of the filter medium due to the pulsation of the air flow or the like, and depends on the pulsation amplitude, pulsation frequency, and flow velocity. In the present embodiment, the movement of the dust due to the pulsation of the air flow is prevented by making the first filter layer 3 wet. <Dust Cleaning Efficiency> Dust cleaning efficiency = Dust trapping amount of filter medium (g) / (Dust trapping amount of filter medium (g) +
Dust amount (g) permeating through the filter medium. The dust cleaning efficiency is
Affected by the flow velocity and aperture of the air passing through the filter media. The dust cleaning efficiency is almost the same between the comparative example and the present embodiment. <Carbon Capture Amount> The nonwoven fabric itself has high carbon capture performance. According to the filter medium 1 of the present embodiment, since the thickness can be reduced, the filtration area can be increased. For this reason, the amount of captured carbon can be improved. <Carbon cleaning efficiency> Carbon cleaning efficiency =
Carbon capture amount (g) of filter medium / (carbon capture amount (g) of filter medium + carbon amount (g) permeating filter medium). The carbon cleaning efficiency is affected by the flow velocity and the aperture of the air passing through the filter medium. The carbon cleaning efficiency is almost the same between the comparative example and the present embodiment. As described above, according to the present invention, by impregnating the first filter layer with oil, the re-emission of the captured dust from the first filter layer can be suppressed. Can be. In addition, the second filter layer having the property of repelling oil suppresses the movement of the oil of the first filter layer to the second filter layer. For this reason, the amount of dust permeated, which is the amount of trapped dust released from the filter medium, can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of an air cleaner element of the present invention. FIG. 2 is a sectional view showing a filter medium. FIG. 3 is a perspective view showing another example of the air cleaner element ((a) and (b) in the figures show examples in which the filter medium is bent into a panel type, and (c) in the figure shows the filter medium stretched in a plane shape. Example). FIG. 4 is a perspective view showing another example of the filter medium ((a) in the figure shows an example formed in a cylindrical shape, and (b) in the figure shows an example formed in a chrysanthemum flower shape). FIG. 5 is a graph showing the performance of the filter medium of the present embodiment as compared with a comparative example. FIG. 6 is a structural diagram of a filter medium of a comparative example. [Description of Signs] 1 ... Filter medium 3 ... First filter layer 4 ... Second filter layer 10 ... Air cleaner element

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 35/024 F02M 35/024 511G (72) Inventor Toshiki Oba 7800 Nakase, Hamakita City, Shizuoka Prefecture Toyo Toro ▼ Machine Manufacturing Co., Ltd. F term (reference) 4D019 AA01 BA13 BB03 BB10 BC09 BC20 BD02 CB03 CB04 DA01

Claims (1)

Claims: 1. A first filter layer made of a nonwoven fabric, and a first filter layer provided downstream of the first filter layer.
A second filter layer made of a nonwoven fabric finer than the nonwoven fabric of the filter layer, wherein the first filter layer is impregnated with oil, and the second filter layer has a property of repelling oil. An air cleaner element, characterized in that: 2. The first filter layer is composed of a plurality of layers stacked so as to be coarser toward the upstream, and wherein the thickness of the first filter layer is equal to the thickness of the second filter layer. The air cleaner element according to claim 1 , wherein the air cleaner element is thicker than a thickness of the air cleaner element.