JP2000170608A - Exhaust gas recirculation device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the flow of exhaust gas from being worsened caused by deposition of carbon, by strapping foreign matter in an exhaust gas recirculation passage even if the foreign matter of whatever materials. SOLUTION: Fine foreign matter contained in exhaust gas is allowed to flow together with exhaust gas to an exhaust gas recirculation chamber 13 through a first exhaust gas recirculation pipe 12. The fine foreign matter is moved along the lower wall surface by their weights regardless of their materials and then trapped by a foreign matter trapping part 16 in a recessed part 13a of the lower wall surface. Since the foreign matter trapping part 16 is arranged in the recessed part 13a of the lower wall surface, it is hardly exposed to carbon of exhaust gas flowing in the exhaust gas recirculation chamber 13, and the degree of deposition of carbon to the foreign matter trapping part 16 is low. Moreover, even if carbon of the exhaust gas is deposited on the foreign matter trapping part 16, the flow of the exhaust gas is not deteriorated caused by the deposition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation apparatus for an internal combustion engine which suppresses the generation of Nox by recirculating a part of exhaust gas discharged from the internal combustion engine from an exhaust system to an intake system.

[0002]

2. Description of the Related Art Generally, in an exhaust gas recirculation device,
An exhaust gas recirculation control valve is provided in an exhaust gas recirculation passage for recirculating a part of the exhaust gas from the exhaust system to the intake system, and the exhaust gas recirculation control valve controls the exhaust gas recirculation flow rate by opening and closing.

In addition to the exhaust gas, various foreign substances enter the exhaust gas recirculation passage. As this foreign matter, for example, there is a foreign matter formed during the manufacture of the internal combustion engine,
There is a cooling of welding sparks (spatter), metal chips, ceramic powder and the like. If such foreign matter adheres to the exhaust gas recirculation control valve, the exhaust gas recirculation flow rate cannot be properly controlled.

[0004] For this reason, for example, Japanese Patent Application Laid-Open No. 63-13286.
In the device described in Japanese Patent Application Publication No. 7 (1999), a mesh-like collection magnet is arranged in the gas circulation passage, and iron powder is attracted to the collection magnet, and the iron powder moves to the exhaust gas circulation control valve. It is blocking.

[0005]

However, in the above-mentioned conventional apparatus, iron powder is adsorbed by magnetic force.
Non-magnetic foreign substances such as aluminum and ceramics cannot be adsorbed. Further, when the mesh of the collection magnet is made fine so that foreign matter of a non-magnetic material can be captured, carbon of the exhaust gas easily adheres to the mesh of the collection magnet, and the mesh is clogged to form an exhaust gas recirculation passage. Exhaust gas flow at

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and any foreign matter of any material can be captured in the exhaust gas recirculation passage, and carbon deposits can be prevented. It is an object of the present invention to provide an exhaust gas recirculation device for an internal combustion engine, which does not cause deterioration of the flow of exhaust gas due to the exhaust gas.

[0007]

In order to solve the above-mentioned problems, the present invention provides an exhaust gas recirculation control valve provided in an exhaust gas recirculation passage communicating between an exhaust system and an intake system. In the device, at a portion of the exhaust gas recirculation passage from the exhaust system to the exhaust gas recirculation control valve,
The wall surface of the passage is partially formed by the foreign matter capturing portion.

According to the present invention, since the foreign matter capturing portion is disposed in the portion of the exhaust gas recirculation passage from the exhaust system to the exhaust gas recirculation control valve, foreign matter entering the exhaust gas recirculation passage from the exhaust system can be prevented. Before reaching the exhaust gas recirculation control valve, it is captured by the foreign matter capturing unit. In addition, the foreign matter capturing portion partially forms a wall surface of the exhaust gas recirculation passage,
Since it does not cross the passage, even if carbon adheres, the flow of exhaust gas hardly deteriorates.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of the exhaust gas recirculation device of the present invention.
1 schematically illustrates an embodiment. In FIG. 1, a manifold converter 11 has a built-in catalyst and is inserted between an internal combustion engine and an exhaust pipe (neither is shown). Exhaust gas from the internal combustion engine is passed through the catalyst of the manifold converter 11 to purify the exhaust gas.

A first exhaust gas recirculation pipe 12 is connected to the manifold converter 11, an exhaust gas recirculation chamber 13 is connected to the first exhaust gas recirculation pipe 12, and a second exhaust gas recirculation pipe 14 is connected to the exhaust gas recirculation chamber 13. Is connected.

An exhaust gas recirculation control valve 15 is provided in the exhaust gas recirculation chamber 13. The exhaust gas recirculation control valve 15 opens or closes to open or close the first and second exhaust gas recirculation pipes 12 and 14.

A part of the exhaust gas led to the manifold converter 11 is supplied to the exhaust gas recirculation pipe 12 → the exhaust gas recirculation control valve 15 of the exhaust gas recirculation chamber 13 → the second exhaust gas recirculation pipe 14. Through the intake system and mixed with the combustion gas in the intake system.

In the exhaust gas recirculation chamber 13, a concave portion 13a is formed on the wall surface of the exhaust gas recirculation chamber 13, and a foreign substance capturing portion 16 is disposed in the concave portion 13a. This foreign matter capturing unit 16
For example, a lump formed by rolling an extremely thin wire. Alternatively, it may be a scourer-like lump made of a thin wire, a lump of metal in a perforated chamber, or the like, and may not be made of metal as long as it has heat resistance. In short, if the welding sparks (spatters) are cooled, fine foreign substances such as metal chips and ceramic powder are easily caught, and these foreign substances can be captured, and if they have heat resistance, , May be anything.

In such a configuration, when the exhaust gas recirculation control valve 15 of the exhaust gas recirculation chamber 13 is opened,
Part of the exhaust gas flows from the manifold converter 11 to the intake system via the exhaust gas recirculation path. At this time,
Along with the exhaust gas, fine foreign matter contained in the exhaust gas is also the first
The gas flows into the exhaust gas recirculation chamber 13 through the exhaust gas recirculation pipe 12. Regardless of the material, the fine foreign matter moves along the lower wall surface of the exhaust gas recirculation chamber 13 due to its weight, and the foreign matter capturing portion 1 of the concave portion 13a of the lower wall surface.
6 captured. For this reason, fine foreign matter does not move to the exhaust gas recirculation control valve 15 and adheres to the valve 15, and the fine foreign matter does not adversely affect the exhaust gas recirculation control.

Further, since the foreign matter capturing portion 16 is disposed in the concave portion 13a on the lower wall surface, it hardly touches the carbon of the exhaust gas flowing into the exhaust gas recirculation chamber 13, and the carbon is transferred to the foreign material capturing portion 16. The degree of adhesion is small. In addition, even if the carbon of the exhaust gas adheres to the foreign matter capturing unit 16, the flow of the exhaust gas does not deteriorate.

FIG. 2 shows a second embodiment of the exhaust gas recirculation device of the present invention.
1 schematically illustrates an embodiment. In FIG. 2, the same reference numerals are given to the portions that perform the same operations as those of the apparatus in FIG. 1, and the description will be simplified.

In the second embodiment, two recesses 13a and 13b are provided in the exhaust gas recirculation chamber 13, and these recesses 13a and 13b are provided.
The foreign material capturing units 16a and 16b are arranged at the positions a and 13b.

When fine foreign matter contained in the exhaust gas flows into the exhaust gas recirculation chamber 13 with great force, the fine foreign matter easily collides with the end wall of the exhaust gas recirculation chamber 13.
A recess 13b is provided in the wall at the end of the recess 13b.
Since the foreign matter capturing portion 16b is disposed at the position b, the foreign matter capturing portion 16b can capture fine foreign matter that has flowed vigorously.

FIG. 3 shows a third embodiment of the exhaust gas recirculation device according to the present invention.
1 schematically illustrates an embodiment. In FIG. 3, the same reference numerals are given to the portions that perform the same operations as those of the apparatus in FIG. 1, and the description will be simplified.

The apparatus according to the third embodiment has the simplest structure, and the foreign matter capturing portion 1 is provided on the lower wall surface of the exhaust gas recirculation chamber 13.
6 is fixed. The function and effect of the foreign matter capturing unit 16 are the same as those of the first and second embodiments.

FIG. 4 (a) schematically shows a fourth embodiment of the exhaust gas recirculation device of the present invention. FIG. 4 (a)
In FIG. 6, the same reference numerals are given to the parts that perform the same operations as those of the apparatus in FIG. 1, and the description will be simplified.

In the fourth embodiment, a labyrinth structure 21 is disposed in the exhaust gas recirculation chamber 13 before the exhaust gas recirculation control valve 15. This labyrinth structure 21
As shown in FIG. 4B, a plurality of plates 21a are alternately arranged in an exhaust gas recirculation path, and these plates 21a
This causes the flow of the exhaust gas to meander.

The labyrinth structure 21 prevents large foreign matter contained in the exhaust gas that has not been completely captured by the foreign matter capturing section 16 irrespective of the material, and protects the exhaust gas recirculation control valve 15 from the large foreign matter.

FIG. 5 (a) schematically shows a fifth embodiment of the exhaust gas recirculation device of the present invention. FIG. 5 (a)
In the figure, the parts that perform the same operations as those of the apparatus shown in FIG.

In the fifth embodiment, the cyclone structure 22 is disposed in the exhaust gas recirculation chamber 13 before the exhaust gas recirculation control valve 15. This cyclone structure 22
As shown in FIG. 5B, a spiral plate 22a is arranged in an exhaust gas recirculation path, and the spiral gas flow is made spiral by the spiral plate 22a.

Like the labyrinth structure 21, the cyclone structure 22 also prevents large foreign matter contained in the exhaust gas, and removes the large foreign matter from the exhaust gas recirculation control valve 1.
Protect 5

FIG. 6 shows a sixth embodiment of the exhaust gas recirculation device of the present invention.
1 schematically illustrates an embodiment. In FIG. 6, the same reference numerals are given to the portions that perform the same operations as those of the apparatus in FIG. 1, and the description will be simplified.

In the sixth embodiment, the porous structure 23 is disposed in the exhaust gas recirculation chamber 13 before the exhaust gas recirculation control valve 15. As shown in FIG. 7, the porous structure 23 is a cylindrical body having a bottom, and has a large number of holes 23a formed on the side wall thereof, and allows exhaust gas to pass through each hole 23a.

Like the labyrinth structure 21 and the cyclone structure 22, the porous structure 23 also prevents large foreign matter contained in the exhaust gas and protects the exhaust gas recirculation control valve 15 from the large foreign matter.

In the apparatus shown in FIG. 1, a gasket 31 is interposed between the first exhaust gas recirculation pipe 12 and the exhaust gas recirculation chamber 13, and the exhaust gas passes through a central hole of the gasket 31.

FIG. 8 shows a modification of the gasket in the apparatus of FIG. The gasket 32 shown in FIG. 8 has a hole 33 through which the exhaust gas passes, and a plurality of projections 34 extending to the center of the hole 33 are provided on the periphery of the hole 33.

This gasket 32 has a plurality of projections 34
This prevents large foreign matter contained in the exhaust gas, and protects the exhaust gas recirculation control valve 15 from the large foreign matter.

Therefore, when the gasket 32 is applied, the labyrinth structure 21, the cyclone structure 22,
Since the porous structure 23 is not required, the number of parts and the cost do not increase.

FIG. 9 shows another example of the gasket in the apparatus of FIG. The gasket 41 shown in FIG. 9 has a hole 42 through which the exhaust gas passes, and a large number of wires 43 are wound around the hole 42.

The gasket 41 prevents large foreign substances contained in the exhaust gas and protects the exhaust gas recirculation control valve 15 from the large foreign substances. In addition, this gasket 4
No. 1 adds a function of preventing a large foreign substance without increasing the number of parts and the cost.

FIG. 10 partially shows another example of the gasket in the apparatus of FIG. In FIG. 10, the end of each strip 51 is bent at a substantially right angle, and a gap is formed between the ends. Many strips 5 having such a structure
By arranging 1 in the hole of the gasket, a function of blocking large foreign substances can be added to the gasket.

FIGS. 11A and 11B show still another example of the gasket in the apparatus shown in FIG. The gasket 61 shown in FIG. 11 has a hole 62 through which the exhaust gas passes. In the hole 62, each of the wavy strips 63 is laid in the horizontal direction, and each of the flat strips 64 is vertically extended. It is hung in the direction. The wavy strips 63 are arranged such that the waveforms of the adjacent strips 63 are alternated. The flat strips 64 are arranged so as to pass through the centers of the staggered waveforms.

The gasket 61 prevents large foreign substances contained in the exhaust gas and protects the exhaust gas recirculation control valve 15 from the large foreign substances. In addition, a function of preventing a large foreign substance is added without increasing the number of parts and the cost.

When the gasket shown in FIGS. 8 to 11 is used in combination with the foreign matter capturing portion shown in FIGS. 1 to 3, both fine foreign matter and large foreign matter can be captured. In addition, if only a large foreign matter is to be captured, the gasket shown in FIGS. 8 to 11 may be provided without providing the foreign matter capturing portion shown in FIGS. 1 to 3. It does not have to be accompanied.

The present invention is not limited to the above embodiments, but can be variously modified. For example,
The arrangement position of the foreign matter capturing portion may be any position as long as it is a part of the exhaust gas recirculation path in front of the exhaust gas recirculation control valve, and the number of disposed portions may be increased. Alternatively, an annular groove may be formed in the inner peripheral wall of the exhaust gas recirculation path, and the foreign matter capturing portion may be disposed in the annular groove.

[0042]

As described above, according to the present invention, the foreign matter trapping portion is disposed in the exhaust gas recirculation passage from the exhaust system to the exhaust gas recirculation control valve. The foreign matter that has entered the recirculation passage is captured by the foreign matter capturing unit before reaching the exhaust gas recirculation control valve. This protects the exhaust gas recirculation control valve from foreign matter.

Further, since the foreign matter capturing portion partially forms the wall surface of the exhaust gas recirculation passage and does not cross the exhaust gas recirculation passage, even if carbon adheres, deterioration of the flow of the exhaust gas is prevented. There is almost no invitation.

[Brief description of the drawings]

FIG. 1 is a partial sectional view schematically showing a first embodiment of an exhaust gas recirculation device of the present invention.

FIG. 2 is a partial sectional view schematically showing a second embodiment of the exhaust gas recirculation device of the present invention.

FIG. 3 is a partial sectional view schematically showing a third embodiment of the exhaust gas recirculation device of the present invention.

FIG. 4A is a partial sectional view schematically showing a fourth embodiment of an exhaust gas recirculation device of the present invention, and FIG. 4B is a perspective view schematically showing a labyrinth structure in FIG.

5A is a partial cross-sectional view schematically showing an exhaust gas recirculation device according to a fifth embodiment of the present invention, and FIG. 5B is a perspective view schematically showing a cyclone structure in FIG.

FIG. 6 is a partial sectional view schematically showing an exhaust gas recirculation device according to a sixth embodiment of the present invention.

FIG. 7 is a side view showing the porous structure in FIG.

FIG. 8 is a plan view showing a modification of the gasket in the apparatus of FIG.

FIG. 9 is a plan view showing another example of the gasket in the apparatus of FIG.

FIG. 10 is a perspective view partially showing another example of the gasket in the apparatus of FIG. 1;

11 (a) is a plan view showing still another example of the gasket in the apparatus of FIG. 1, and FIG. 11 (b) is AA in FIG.
FIG.

[Explanation of symbols]

 11 Manifold Converter 12 First Exhaust Gas Recirculation Pipe 13 Exhaust Gas Recirculation Chamber 14 Second Exhaust Gas Recirculation Pipe 15 Exhaust Gas Recirculation Control Valve 16 Foreign Material Capture Unit 21 Labyrinth Structure 22 Cyclone Structure 23 Porous Structure 31, 32, 41, 61 Gasket

Claims (1)

[Claims] 1. An exhaust gas recirculation device for an internal combustion engine, wherein an exhaust gas recirculation control valve is provided in an exhaust gas recirculation passage communicating between an exhaust system and an intake system. The exhaust gas recirculation device for an internal combustion engine, wherein a wall surface of the passage is partially formed by a foreign matter capturing portion at a portion of the exhaust gas recirculation passage.