WO2017216838A1

WO2017216838A1 - Exhaust gas recirculation valve

Info

Publication number: WO2017216838A1
Application number: PCT/JP2016/067520
Authority: WO
Inventors: 智広奥村; 拓朗頭井; 健篠▲崎▼
Original assignee: 三菱電機株式会社
Priority date: 2016-06-13
Filing date: 2016-06-13
Publication date: 2017-12-21
Also published as: JP6501975B2; JPWO2017216838A1

Abstract

Exhaust gas enters from an exhaust gas inflow port (21) into the exhaust gas recirculation valve (1). An annular rib (25) protruding toward the exhaust gas inflow port (21) is disposed on a wall part (24) located on the opposite side of a housing (2) from the exhaust gas inflow port (21).

Description

Exhaust gas recirculation valve

This invention relates to an exhaust gas recirculation valve that recirculates exhaust gas to the intake side.

Conventionally, there has been known an exhaust gas recirculation valve that guides and circulates part of exhaust gas generated in an internal combustion engine to the intake side. For example, in the exhaust gas recirculation valve described in Patent Document 1, two exhaust gas outlets arranged vertically in the axial direction are provided with respect to the exhaust gas inlet. Therefore, the wall of the housing located between the two exhaust gas outlets faces the exhaust gas inlet.

JP 2012-26270 A

When the wall of the housing faces the exhaust gas inlet, high-temperature exhaust gas flowing from the exhaust gas inlet directly hits the wall. The wall portion is heated by direct hitting of high-temperature exhaust gas, so it must be designed to withstand such high temperature. For example, although the cost is high, the housing is made of a high heat resistant material.

The present invention has been made in order to solve the above-described problems. Even when the wall portion of the housing is opposed to the exhaust gas inlet, the exhaust gas can reduce the temperature rise of the wall portion. The purpose is to obtain a recirculation valve.

An exhaust gas recirculation valve according to the present invention includes a housing having therein a passage that connects an exhaust gas inlet and an exhaust gas outlet, and a valve body that is provided inside the housing and opens and closes the passage. And a wall portion facing the exhaust gas inlet, and ribs that are continuously or intermittently arranged in a frame shape on the wall and projecting toward the exhaust gas inlet.

According to the present invention, by providing the rib on the wall portion of the housing that faces the exhaust gas inlet, even if the wall portion of the housing faces the exhaust gas inlet, the temperature of the wall portion is increased. Can be reduced.

1 is a partial cross-sectional view showing an exhaust gas recirculation valve according to Embodiment 1 of the present invention. It is a front view of the wall part when it sees from the A direction in FIG. It is sectional drawing which shows the mode of the exhaust gas around a wall part. It is sectional drawing which shows the modification of a rib. It is sectional drawing which shows the modification of the exhaust-gas recirculation valve which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the exhaust-gas recirculation valve which concerns on Embodiment 2 of this invention.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a partial cross-sectional view showing an exhaust gas recirculation valve 1 according to Embodiment 1 of the present invention. In FIG. 1, the actuator portion 9, the cover member 11, the gasket 10 and the like are shown as side views. FIG. 2 is a front view of the wall portion 24 when viewed from the direction A in FIG.

An exhaust gas inlet 21 and two

exhaust gas outlets

22 and 23 are formed in the housing 2 of the exhaust gas recirculation valve 1. The interior of the housing 2 is a passage that connects the exhaust gas inlet 21 and the

exhaust gas outlets

22 and 23. The passage is opened and closed by a valve body 3 provided inside the housing 2. FIG. 1 shows a state in which the passage is closed by the valve body 3.
The exhaust gas inlet 21 faces the wall portion 24 of the housing 2. As shown in FIG. 2, an annular rib 25 is formed on the wall portion 24 when viewed from the direction A in FIG. 1. The rib 25 is convex toward the exhaust gas inlet 21.

An exhaust gas outlet 22 is formed on the upper side in FIG. 1 when viewed from the wall 24, and an exhaust gas outlet 23 is formed on the lower side. An annular valve seat 4 is fixed to the housing 2 in the middle of the passage from the exhaust gas inlet 21 to the exhaust gas outlet 22 and in the middle of the passage from the exhaust gas inlet 21 to the exhaust gas outlet 23. Has been.

The valve body 3 is fixed to the valve shaft 5 and moves in the axial direction integrally with the valve shaft 5.
The valve shaft 5 is supported by a bearing 6. A spring holder 7 is fixed to the upper end of the valve shaft 5 in FIG. A spring 8 provided between the spring holder 7 and the housing 2 urges the valve shaft 5 in a direction in which the valve body 3 comes into contact with the valve seat 4.

The housing 2 is provided with an actuator unit 9 having a motor and the like. The output shaft 91 of the actuator unit 9 moves the valve shaft 5 in a direction in which the valve body 3 is separated from the valve seat 4.

In the housing 2, a cover member 11 is attached via a gasket 10 on the side where the

exhaust gas outlets

22 and 23 are formed. The cover member 11 is provided with a connection portion 12 for connection to an intake side of an internal combustion engine (not shown).

In the exhaust gas recirculation valve 1, when the internal combustion engine is operated, the output shaft 91 of the actuator unit 9 moves the valve shaft 5 downward in FIG. 1 against the urging force of the spring 8. Thereby, a flow path is formed between the valve body 3 and the valve seat 4, and the exhaust gas flows from the exhaust gas inlet 21 to the

exhaust gas outlets

22 and 23.

The state of the exhaust gas around the wall 24 when the exhaust gas flows from the exhaust gas inlet 21 to the

exhaust gas outlets

22 and 23 is shown in FIG.
The exhaust gas that has entered the inside of the housing 2 from the exhaust gas inlet 21 collides with the wall portion 24 on the front surface, and generates a turbulent flow as shown in FIG. After that, the exhaust gas continues to enter the inside of the housing 2 from the exhaust gas inlet 21, but the generated turbulent flow remains in the region B by the ribs 25, and the exhaust gas entering the inside of the housing 2 becomes the wall portion. Suppresses hitting 24 directly. The temperature of the turbulent flow in the region B is lowered by heat exchange with the wall portion 24, and the wall portion 24 faces the exhaust gas inlet 21 through which the high-temperature exhaust gas is introduced through the exhaust gas whose temperature has decreased. To do. As described above, in the region B, the heat insulation barrier layer is formed by the turbulent flow stayed by the rib 25.

On the other hand, when the rib 25 is not formed on the wall 24, the turbulent flow generated by the exhaust gas entering the housing 2 from the exhaust gas inlet 21 colliding with the wall 24 may remain in the region B. become unable. Therefore, the exhaust gas that subsequently enters the inside of the housing 2 from the exhaust gas inlet 21 hits the wall portion 24 directly, and compared with the case where the rib 25 that forms the heat insulating barrier layer is provided. The part 24 becomes hot.

By forming the heat insulating barrier layer by providing the ribs 25, it is possible to reduce the high temperature of the wall portion 24. Instead of the high heat resistant material such as iron or stainless steel as the material of the housing 2, the heat resistant temperature is Low but low cost aluminum can be employed. Since aluminum is lighter than iron and stainless steel, it contributes to weight reduction of the exhaust gas recirculation valve 1.

The rib 25 may have a shape other than the substantially perfect circle as shown in FIG. 2 as long as the shape when viewed from the A direction is a frame shape. For example, an ellipse having a different major axis and a minor axis, a rounded polygon, or the like may be used. Further, when viewed from the A direction, instead of the continuous rib 25, the intermittent rib 25, that is, the rib 25 may be partially interrupted. In short, the ribs 25 may be continuously or intermittently arranged in a frame shape so that a heat insulating barrier layer can be formed.

The rib 25 is preferably formed such that its diameter C is smaller than the diameter D of the exhaust gas inlet 21. Diameter C and diameter D are shown in FIG.
By not increasing the diameter C, the influence on the flow rate characteristics of the exhaust gas recirculation valve 1 due to the provision of the rib 25 can be suppressed. Further, since the exhaust gas that has entered the inside of the housing 2 from the exhaust gas inlet 21 is guided to the

exhaust gas outlets

22 and 23 by the pressure difference, the flow spreads in a trumpet shape as shown in FIG. Therefore, a part of the exhaust gas that enters the inside of the housing 2 from the exhaust gas inlet 21 does not flow so as to hit the wall portion 24 directly from the front, so that the diameter C of the rib 25 is the diameter D of the exhaust gas inlet 21. Even smaller than this is sufficient for reducing the increase in the temperature of the wall 24.
Considering the case where the shape of the rib 25 when viewed from the direction A in FIG. 1 is other than circular, the outline of the inner region of the rib 25 formed by being surrounded by the inner peripheral surface 26 of the rib 25 is What is necessary is just to make it smaller than the external shape of the flow-path cross section of the exhaust gas inflow port 21. FIG.

Further, as shown in the cross-sectional view of FIG. 4, the inner peripheral surface 26 of the rib 25 may be a concave surface that is positioned closer to the inner peripheral side of the rib 25 as it approaches the wall portion 24. By doing in this way, the turbulent flow wound as shown in FIG.
Further, the outer peripheral surface 27 of the rib 25 may be a concave surface that is positioned closer to the outer peripheral side of the rib 25 as it approaches the wall portion 24. By doing in this way, it becomes easy to produce a turbulent flow in the outer peripheral part of the rib 25. The turbulent flow is effective in reducing the increase in temperature at the portion of the wall portion 24 located on the outer periphery of the rib 25.

Further, if the ribs 25 are too low, the heat insulating barrier layer is difficult to be formed properly, and therefore the height of the ribs 25 is preferably 2 mm or more.
Further, if the rib 25 is too high, the rib 25 and the valve body 3 approach each other at the time of valve opening and affect the flow characteristics such as a decrease in the flow rate. Therefore, the height of the rib 25 is preferably 5 mm or less. The wall 24 may be moved away from the valve shaft 5, that is, in the direction of the cover member 11 so that the rib 25 and the valve body 3 do not approach when the valve is opened. Since the design change of moving the wall portion 24 in addition to the formation of the rib 25 is required for the structure, the manufacturing becomes complicated.

In the above description, a so-called multi-valve valve having a plurality of valve bodies 3 and valve seats 4 has been described as an example. However, the exhaust gas recirculation valve 1 may be a so-called single valve type valve in which one valve body 3 and one valve seat 4 are provided.
FIG. 5 shows an example in which the exhaust gas recirculation valve 1 is a single valve type valve. Also in the case of the single valve type, by providing the rib 25 on the wall portion 24 facing the exhaust gas inlet 21, the heat insulating barrier layer can be formed, and the temperature rise of the wall portion 24 can be reduced.

As described above, according to the exhaust gas recirculation valve 1 according to the first embodiment, the heat insulating barrier layer is formed by providing the rib 25 on the wall portion 24 facing the exhaust gas inlet 21. Thereby, even if it is the structure where the wall part 24 of the housing 2 is facing the exhaust gas inflow port 21, the high temperature of the wall part 24 can be reduced.

Further, the outer shape of the inner region of the rib 25 is smaller than the outer shape of the flow path cross section of the exhaust gas inlet 21. If it does in this way, high temperature of the wall part 24 can be reduced, suppressing the influence on flow volume characteristic.

Further, the inner peripheral surface 26 of the rib 25 is a concave surface positioned closer to the inner peripheral side as it approaches the wall portion 24. If it does in this way, it will become easy to produce turbulent flow.

Further, the outer peripheral surface 27 of the rib 25 is a concave surface positioned closer to the outer peripheral side as it approaches the wall portion 24. If it does in this way, it will become easy to produce turbulent flow.

Further, the height of the rib 25 is 2 mm or more and 5 mm or less. If it does in this way, a heat insulation barrier layer will be easy to be formed appropriately, and manufacture will not become complicated.

The housing 2 is made of aluminum. The aluminum housing 2 is low-cost and lightweight.

Embodiment 2. FIG.
FIG. 6 shows a cross-sectional view of an exhaust gas recirculation valve 1 according to Embodiment 2 of the present invention. Note that components having the same or corresponding functions as those already described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified. Moreover, about a part structure of the spring 8, the actuator part 9, etc., it is the same as that of FIG. 1, and abbreviate | omitting illustration.
The exhaust gas recirculation valve 1 according to the second embodiment is different from the first embodiment in that a water cooling passage 13 is provided in contact with the back surface 28 of the surface of the wall portion 24 facing the exhaust gas inlet 21. Different from 1.
By providing the water cooling passage 13, the temperature of the wall 24 can be further reduced as compared with the first embodiment.

At that time, the water cooling passage 13 is preferably provided with a guide member for directing the cooling water toward the wall portion 24 so that the cooling water flowing through the water cooling passage 13 can cool the wall portion 24 more efficiently. . As such a guide member, FIG. 6 illustrates a case where a partition 14 is provided. The partition 14 is a wall extending from the housing 2 forming the water cooling passage 13 toward the inside of the water cooling passage 13.

When the partition 14 is not provided, the cooling water tends to flow along the shortest path along the flow E when going from the inlet 13a to the outlet 13b. For this reason, the flow rate of the cooling water is high in the vicinity of the flow E, and the flow rate of the cooling water is decreased in the vicinity of the wall portion 24. Therefore, it becomes difficult to efficiently cool the wall portion 24.
On the other hand, by providing the partition 14, the cooling water flows along a path along the flow F when it goes from the inlet 13 a to the outlet 13 b, and the cooling water can be directed to the wall portion 24. In this way, the flow rate of the cooling water near the wall portion 24 is increased, and the wall portion 24 is efficiently cooled.

In the water cooling passage 13, fins 15 extend from the wall portion 24 toward the cover member 11, and the fins 15 promote heat exchange between the wall portion 24 and the cooling water.
Depending on the temperature of the exhaust gas entering the housing 2 from the exhaust gas inlet 21, the partitions 14 or the fins 15 may be omitted as appropriate.

FIG. 6 shows a configuration when the partition 14 is extended from the housing 2 toward the inside of the water cooling passage 13. However, by extending the wall from the cover member 11 toward the inside of the water cooling passage 13, that is, toward the wall portion 24, the wall may function as a guide member for directing the cooling water toward the wall portion 24 in the same manner as the partition 14.

As described above, according to the exhaust gas recirculation valve 1 according to the second embodiment, by providing the water cooling passage 13, the temperature of the wall portion 24 can be further reduced as compared with the first embodiment.

In addition, an induction member provided in the water cooling passage 13 and directing the cooling water flowing through the water cooling passage 13 toward the wall portion 24 is provided. If it does in this way, the flow rate of the cooling water which flows through the water-cooling channel | path 13 will become quick also in the wall part 24 vicinity, the wall part 24 will be cooled efficiently, and the high temperature of the wall part 24 can further be reduced.

In the invention of the present application, within the scope of the invention, any combination of the embodiments, a modification of any component of each embodiment, or omission of any component in each embodiment is possible. is there.

As described above, even if the exhaust gas recirculation valve according to the present invention has a structure in which the wall portion of the housing faces the exhaust gas inflow port, since the temperature rise of the wall portion can be reduced, It is suitable for use when the exhaust gas is recirculated.

1 Exhaust gas recirculation valve, 2 housing, 3 valve body, 4 valve seat, 5 valve shaft, 6 bearing, 7 spring holder, 8 spring, 9 actuator part, 10 gasket, 11 cover member, 12 connection part, 13 water cooling passage , 13a inlet, 13b outlet, 14 partitions, 15 fins, 21 exhaust gas inlet, 22, 23 exhaust gas outlet, 24 walls, 25 ribs, 26 inner peripheral surface, 27 outer peripheral surface, 28 rear surface, 91 output shaft.

Claims

A housing having therein a passage connecting the exhaust gas inlet and the exhaust gas outlet;
A valve body provided inside the housing and opening and closing the passage;
The housing is
A wall facing the exhaust gas inlet;
An exhaust gas recirculation valve characterized by having a rib protruding toward the exhaust gas inlet, which is continuously or intermittently arranged in a frame shape on the wall portion.
The exhaust gas recirculation valve according to claim 1, wherein an outer shape of an inner region of the rib is smaller than an outer shape of a flow path cross section of the exhaust gas inlet.
The exhaust gas recirculation valve according to claim 1, wherein the inner peripheral surface of the rib is a concave surface positioned closer to the inner peripheral side as it approaches the wall portion.
The exhaust gas recirculation valve according to claim 1, wherein the outer peripheral surface of the rib is a concave surface positioned closer to the outer peripheral side as approaching the wall portion.
The exhaust gas recirculation valve according to claim 1, wherein the height of the rib is 2 mm or more and 5 mm or less.
The exhaust gas recirculation valve according to claim 1, further comprising a water cooling passage that contacts a back surface of a surface of the wall portion facing the exhaust gas inlet.
The exhaust gas recirculation valve according to claim 6, further comprising a guide member provided in the water cooling passage and directing cooling water flowing through the water cooling passage toward the wall portion.
The exhaust gas recirculation valve according to claim 1, wherein the housing is made of aluminum.