JPH0246247B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a heat-resistant EGR passage installed in a recirculation passage that recirculates exhaust gas discharged from an engine's discharge port to an intake port via a control valve. Regarding gender filters.

(Prior technology) Conventionally, in order to lower the combustion temperature and reduce the generation of NOx, exhaust gas discharged from the engine's discharge port into the exhaust passage is recirculated to the intake passage upstream of the engine's intake port. A reflux passage (hereinafter referred to as EGR passage) is provided.
This EGR passage is provided with a control valve that is opened by, for example, intake negative pressure.
In addition, there is a risk that soot and lead components from leaded gasoline may adhere around the valve body of the control valve and reduce the flow rate.To prevent this, a filter is installed at the control valve to remove soot and lead components. It is installed on the upstream side. Such a filter has a structure in which heat-resistant fibers are knitted into a mesh shape to form a rectangular shape and then wound into a cylindrical shape.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional filter, since the square-shaped fibers were simply wound and installed in the EGR passage, both ends of the cylindrically-wound fibers were frayed. Moreover, since the wound fibers have elasticity, the installation work is difficult.

Therefore, an object of the present invention is to provide a heat-resistant filter for an EGR passage that can reliably prevent fraying and improve installation workability.

(Means for Solving the Problems) The filter of the present invention is installed in an EGR passage that recirculates exhaust gas from an engine exhaust passage to an intake passage via a control valve, and is made of heat-resistant fibers woven into a mesh. A cylindrical mesh material that is formed into a rectangular sheet shape and rolled into a cylindrical shape, and a cylindrical mesh material that is attached to the outer periphery of both ends of the cylindrical mesh material and has locking protrusions on the inner peripheral surface. It consists of a cap.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a schematic diagram showing an EGR passage (exhaust gas recirculation passage). In Fig. 1, 1 is a cylinder head, 2 is a cylinder, 3 and 4 are an intake port and an intake passage, and 5 and 6 are an exhaust port and an exhaust passage, and exhaust gas is recirculated from the exhaust passage 6 to the intake passage 4. An EGR passage 7 is provided. This EGR
A control valve 8 is interposed in the passage 7 to open and close the passage 7 according to intake negative pressure. moreover,
An expansion chamber 9 having a predetermined volume and having an inner diameter larger than that of the passage 7 is provided upstream of the control valve 8 in the EGR passage 7, and a filter 10 is attached to the expansion chamber 9.

The filter 10 is composed of a heat-resistant fiber 13 formed by knitting stainless steel fibers, for example, as shown in FIGS. 2a to 6, and a cap 18 as shown in FIGS. 6 to 8b. There is. As shown in FIG. 2a, the fibers 13 are first knitted into a mesh using heat-resistant fibers 11, and the mesh arrangement 12 is arranged on each side 14a, 14b, 15a, 1.
It is formed into a rectangular (quadrangular) sheet shape so as to be diagonal with respect to 5b. The fibers 13 are woven in such a manner that the fibers 11 are woven in a wave pattern on the upper and lower surfaces of the sheet, as shown in FIG. 2b. Then, the fibers 13, as shown in FIG.
A pair of sheet-like opposite sides 14a, 1 facing each other
4b are overlapped and joined to form a cylindrical shape as shown in FIG. Furthermore, as shown by the arrow in FIG. 4, the cylindrical fiber 13 is folded so that the joined opposite sides 14a and 14b are located in the center, and as shown in FIG. It is wound in a cylindrical shape from one cylindrical open end 16b to the other open end 16a so as to be inward.
Formed as shown in the figure.

As shown in FIGS. 6 and 7, the caps 18 are formed into a cylindrical shape that covers the outer periphery of both ends of the fiber 13 wound into a cylindrical shape, and each cap 18 has a bottom surface that prevents the flow of exhaust gas. A hole 19 is formed with a size that does not exceed the size of the hole 19. Furthermore, as shown in FIGS. 8a and 8b, on the inner peripheral surface of each cap 18, two protrusions 20 are provided at each half circumference, which are formed by cutting and raising. Each cap 18 is attached to both ends of the cylindrical fiber 13 by locking the protrusions 20 into the mesh as shown in FIG. It is installed in the expansion chamber 9 as shown in FIG.

In such a filter 10, the mesh-like fibers 13 are formed into a rectangular sheet shape,
By joining a pair of opposite sides to form a cylindrical shape and rolling it into a cylindrical shape with this joint part inside,
This prevents the ends of the cylindrical roll from fraying. In addition, since the caps 18 are attached to the outer periphery of both ends, it is possible to reliably prevent the ends of the fibers 13 from fraying, and the shape of the cylindrically wound fibers 13 can be maintained, improving the workability of installing the filter 10. can. Furthermore, since the fibers 13 are locked by the protrusions 20 provided on the cap 18, the protrusions 20
By appropriately setting the locking position of the filter 10, the filter 10 can be easily positioned in the axial direction in the expansion chamber 9. Furthermore, since a pair of joined opposite sides are wound inward for use, the bulge 17 formed on the outer periphery of the cylindrical fiber by the joined part is not wound into a cylindrical shape, as shown in FIG. fiber 1
The elastic force of No. 3 makes it possible to contact and seal the inner wall surface of the expansion chamber 9. Moreover, since the fibers 13 are knitted in a wavy manner as shown in FIG. An internal space can be formed.

(Effects of the Invention) As is clear from the above description, according to the present invention, the filter is configured by the heat-resistant fibers wound into a cylindrical shape and the caps attached to both ends of the fibers. can prevent fraying. Further, the shape of the cylindrically wound fibers can be maintained by the cap, and by providing the cap with a locking protrusion, the workability of attaching the filter can be improved.

[Brief explanation of the drawing]

Figures 1 to 9 relate to one embodiment of the present invention, in which Figure 1 is a schematic diagram showing an EGR passage, and Figure 2 a.
is a plan view showing a sheet-like heat-resistant fiber, FIG. 2b
is an enlarged view of part A in Fig. 2a, Figs. 3 to 5 are perspective views explaining the process of forming cylindrical heat-resistant fibers, Fig. 6 is an exploded perspective view of the filter, and Fig. 7 is a diagram of the filter. A perspective view, FIG. 8a is a front view of the cap,
FIG. 8b is a sectional view taken along arrow B in FIG. 8a, showing the cap, and FIG. 9 is a schematic sectional view showing the filter installed in the EGR passage. In the drawing, 4 and 6 are intake and exhaust passages, and 7 is
EGR passage, 8 is a control valve, 10 is a filter, 11 is a heat-resistant fiber, 13 is a heat-resistant fiber, 18 is a cap, and 20 is a protrusion.

Claims (1)

[Claims] 1. EGR that recirculates exhaust gas from the engine exhaust passage to the intake passage via a control valve.
A heat-resistant filter installed in a passage includes a mesh material made of heat-resistant fibers formed into a knitted sheet shape and wound into a cylindrical shape, and a mesh material attached to the outer periphery of both ends of this cylindrical-wound mesh material. It consists of a pair of cylindrical caps with locking protrusions on the inner circumferential surface, and passage holes are provided on the bottoms of these cylindrical caps to allow EGR gas to flow in the axial direction of the cylinder. A heat-resistant filter characterized by: