JP2013160155A - Gas introducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable EGR gas G1 and outside air G2 to be efficiently mixed.SOLUTION: A gas introducing device 1 includes a substantially cylindrical housing 2. The inside of the housing 2 is divided into a mixing chamber 11 on an inner side and an outer peripheral passage 10 on an outer side by a cylindrical internal bulkhead 7. An outside air introducing pipe 6 is connected to the internal bulkhead 7 by being inclined to an axial center C1 of the internal bulkhead 7. A cut-out section 7A (opening section) is formed on the internal bulkhead 7 to be on an extension of the axial center C1 of the outside air introducing pipe 6. In the mixing chamber 11, outside air G2 is introduced from the outside air introducing pipe 6, and EGR gas G1 is introduced via the outer peripheral passage 10 and the cut-out section 7A. The inside and outside EGR gas G1 and the outside air G2 are efficiently mixed via the cut-out section 7A.

Description

  The present invention relates to a gas introduction device, and more particularly, to a gas introduction device suitable when, for example, EGR gas and outside air are mixed and then introduced into a combustion chamber.

2. Description of the Related Art Conventionally, as a gas introduction device used for EGR (exhaust gas recirculation device), for example, those having configurations shown in Japanese Patent Application Laid-Open Nos. 2011-179351 and 2010-255581 are known. As shown in these prior examples, the conventional general gas introduction device introduces EGR gas into the housing from the lower side and introduces fresh outside air into the housing from the upper side. Thus, after the EGR gas and the outside air are mixed in the housing, the mixed gas is discharged from the outlet of the housing to the downstream side.
In addition, as a conventional gas introduction device, proposals have been made for suppressing concentration unevenness between EGR gas and outside air (for example, Patent Document 1 and Patent Document 2). That is, in the gas introduction device of Patent Document 1, the inner partition wall 17 is provided in the solid portion of the housing, so that the inner side serves as a mixing chamber (intake passage 14) and the outer side serves as a gas passage. doing. Then, outside air is circulated through the mixing chamber in the housing and EGR gas is supplied to the mixing chamber from the opening of the gas passage so that the outside air and EGR gas are mixed in the mixing chamber and then discharged to the outside. .
On the other hand, in the gas introduction device of Patent Document 2, an inner pipe is disposed in the outer pipe, and through holes serving as outlets 9 for EGR gas are formed at a plurality of locations in the circumferential direction of the inner pipe. Yes. Then, in a state where the outside air is circulated through the intake passage 5 in the inner pipe, by supplying EGR gas to the outer peripheral passage between the outer peripheral portion of the inner pipe and the outer pipe, the plurality of outlets 9 EGR gas is introduced into the intake passage 5 so that the outside air in the intake passage 5 and the EGR gas are mixed.

JP 2001-304050 A JP 2011-64163 A

By the way, in the conventional general gas introduction device, there is a drawback that the concentration unevenness of the mixed gas tends to occur when the EGR gas and fresh outside air are mixed in the housing. More specifically, there is a temperature difference between the EGR gas and the outside air such that the EGR gas is, for example, 100 ° C. and the outside air is 25 ° C. In the conventional gas introduction device, the temperature difference is the cause. Thus, it was difficult to mix the EGR gas and the outside air without concentration unevenness.
In addition, even in the gas introduction devices of Patent Document 1 and Patent Document 2 that are intended to suppress the concentration unevenness of two types of gas, the EGR gas and the outside air are efficiently mixed due to the temperature difference. It is considered difficult to do.

In view of the circumstances described above, the present invention provides a housing having an internal space, and a cylindrical shape that is provided in the housing and divides the internal space of the housing into an inner mixing chamber and an outer peripheral passage. An internal partition, an opening formed in the internal partition and communicating with the mixing chamber and the outer peripheral passage, and connected to the housing so as to be inclined with respect to the axial center of the internal partition to allow outside air to flow into the mixing chamber. An outside air introduction pipe to be introduced, a gas introduction pipe which is connected to the housing and introduces gas into the mixing chamber through the outer peripheral passage and the opening, and mixing of the outside air and the gas mixed in the mixing chamber An outlet for discharging gas to the outside of the housing,
The outside air is introduced into the mixing chamber through the outside air introducing pipe and the gas is introduced from the gas introducing pipe through the outer peripheral passage and the opening to the mixing chamber, and the outside air and the gas are mixed in the mixing chamber and then mixed. In the gas introduction device configured to discharge the gas from the outlet,
A notch as the opening is formed at a position where an extension of the axial center of the outside air introduction tube intersects the internal partition.

  According to such a configuration, as can be understood from temperature measurement data at the outlet described later, the outside air and the gas can be efficiently mixed through the notch as the opening.

Sectional drawing which shows one Example of this invention. Sectional drawing of the principal part which follows the II-II line | wire of FIG. Sectional drawing of the principal part which follows the III-III line | wire of FIG. Sectional drawing which shows the state before the connection of the principal part in FIG. The figure which shows the temperature distribution of the mixed gas in the exit of the Example shown in FIG. The figure which shows the temperature distribution of the mixed gas in the exit of a conventional product. Sectional drawing which shows 2nd Example of this invention. Sectional drawing of the principal part which follows the VIII-VIII line of FIG. Sectional drawing of the principal part which follows the IX-IX line of FIG. Sectional drawing which shows the state before the connection of the principal part in FIG.

  Hereinafter, the present invention will be described with reference to the illustrated embodiments. In FIGS. 1 to 3, reference numeral 1 denotes a gas introduction device for EGR mounted on an automobile. The gas introduction device 1 is configured to receive and mix the EGR gas G1 and fresh outside air G2 into the housing 2, and the mixed gas G3 of the EGR gas G1 and outside air G2 mixed in the housing 2 is: The gas is fed from an outlet 2A of the housing 2 to a combustion chamber (not shown) via a feed pipe 3.

  The gas introduction device 1 includes a substantially cylindrical housing 2, a gas introduction passage 4 that is formed in the bottom of the housing 2 and introduces the EGR gas G 1 into the housing 2, and a valve mechanism that opens and closes the gas introduction passage 4. 5, an outside air introduction pipe 6 that is connected to an axial rear side (right side in FIG. 1) of the housing 2 and introduces outside air into the housing 2, and an axial front side of the housing 2 (left side in FIG. 1) The outlet 2A of the mixed gas G3 formed in the above.

  A thin cylindrical inner partition wall 7 is provided from a position near the front end of the housing 2 to a position close to the rear end. A space on the inner side of the inner partition wall 7 in the housing 2 serves as a mixing chamber 11 for mixing the EGR gas G1 and the outside air G2. An outside air introduction pipe 6 is formed continuously from the inner partition wall 7 to the rear side, and fresh outside air G2 is introduced into the mixing chamber 11 through the outside air introduction pipe 6. The axial center C2 of the outside air introduction pipe 6 is arranged to have a predetermined angle θ with respect to a virtual horizontal plane passing through the axial center C1 of the cylindrical inner partition wall 7. This angle θ can be appropriately set according to the mounting position of the gas introducing device 1 on the automobile.

On the other hand, an annular outer peripheral passage 10 that is continuous in the circumferential direction is formed at an outer position adjacent to the inner partition wall 7, and this outer peripheral passage 10 constitutes an upper portion of the gas introduction passage 4.
The valve mechanism 5 that opens and closes the gas introduction passage 4 includes an annular valve seat 12 formed in a stepped large-diameter hole of the housing 2, and a valve that is connected to and separated from the valve seat 12 by being connected to the lower end portion of the valve shaft 13. And a body 14. An actuator (not shown) is connected to the upper end of the valve shaft 13 passing through the housing 2. When the valve shaft 13 is lifted and lowered by the actuator when necessary, the valve body 14 contacts and separates from the valve seat 12 to introduce gas. The passage 4 is opened and closed. As shown in FIGS. 1 and 2, when the valve body 14 is separated from the valve seat 12 by the actuator and the gas introduction passage 4 is opened, the gas introduction pipe 15 connected to the gas introduction passage 4 is connected. Thus, the EGR gas G1 is introduced into the gas introduction passage 4 and is also introduced into the outer peripheral passage 10 which is an upper portion thereof.

In this embodiment, the EGR gas G1 thus introduced into the outer peripheral passage 10 is introduced into the mixing chamber 11 mainly through the notch 7A as an opening formed in the internal partition wall 7. It has become.
More specifically, the inner partition wall 7 is formed with a long hole-like notch 7A extending from a substantially central portion in the axial direction to a predetermined range in the axial direction. The mixing chamber 11 and the outer peripheral passage 10 communicate with each other through the notch 7A serving as the opening. The axial range in which the notch 7A is formed is substantially the same as the axial range in which the internal partition wall 7 is provided, in other words, as an opening over the axial range in which the outer peripheral passage 10 is formed. The notch 7A is formed.

The cutout portion 7A is formed at a position where the extension line of the axis C2 of the outside air introduction pipe 6 intersects the internal partition wall 7 (see FIG. 2). In the present embodiment, the EGR gas G1 in the outer peripheral passage 10 and a part of the outside air G2 introduced into the mixing chamber 11 are circulated through the notch 7A of the inner partition wall 7 so that mixing is performed. The EGR gas G1 and fresh outside air G2 are efficiently mixed in the chamber 11.
More specifically, when the gas introduction passage 4 is opened by the valve mechanism 5 and the EGR gas G1 is introduced into the outer peripheral passage 10, the maximum air pressure from the outside air introduction pipe 6 toward the notch 7A is also maximized. Fresh outside air G2 is introduced at a flow rate. Therefore, the outside air G2 is introduced into the mixing chamber 11, and at the same time, a part of the outside air G2 passes through the notch 7A and quickly enters the outer peripheral passage 10 and is mixed with the EGR gas G1 there. And the mixed gas G3 mixed in the outer periphery channel | path 10 is introduce | transduced in the mixing chamber 11 through the notch part 7A.

  In this way, the EGR gas G1 in the outer peripheral passage 10 and the outside air G2 introduced into the mixing chamber 11 are circulated through the notch portion 7A of the inner partition wall 7, whereby the mixing chamber 11, the mixed gas G3 can be formed by efficiently mixing the EGR gas G1 and the outside air G2. The mixed gas G3 thus mixed in the mixing chamber 11 is fed from the outlet 2A of the housing 2 to the downstream combustion chamber via the feeding pipe 3.

Here, the temperature distribution of the mixed gas G3 measured at the outlet 2A of the housing 2 with respect to the mixed gas G3 obtained by mixing the fresh outside air G2 at 25 ° C. and the EGR gas G1 at 100 ° C. by the gas introduction device 1 of this embodiment. This is shown in FIG. As can be understood from FIG. 5, the temperature distribution is such that the mixed gas G3 is in the range of about 31 ° C. to about 49 ° C., and the EGR gas G1 when introduced into the housing 2 is 100 ° C. Then, it can be understood that the outside air G2 and the EGR gas G1 are efficiently mixed by the gas introduction device 1.
On the other hand, FIG. 6 shows the temperature distribution of the mixed gas measured at the outlet of the housing for the mixed gas obtained by mixing the fresh outside air of 25 ° C. and the EGR gas of 100 ° C. in the conventional gas introducing device. is there. The conventional gas introduction device here introduces EGR gas into the housing from the lower side as disclosed in, for example, JP-A-2011-179351 and 2010-2555581, and from the upper side. It is configured to introduce fresh outside air into the housing. As can be understood from FIG. 6, in the conventional product, the temperature distribution of the mixed gas is in the range from about 27 ° C. to about 83 ° C., and it can be understood that the temperature difference is large depending on each part on the cross section of the outlet. . As is clear from the comparison with the conventional product, it is clear that the gas introduction device 1 of this embodiment can efficiently mix the outside air G2 and the EGR gas G1.

Next, when the housing 2 and the outside air introduction pipe 6 are formed, the gas introduction device 1 of the present embodiment is characterized by the first member 21 on the axial front side and the second member 22 on the axial rear side. And then casting them in two parts, and then connecting them together in the axial direction.
More specifically, as shown in FIGS. 3 to 4, the first member 21 on the front side includes a substantially cylindrical main body 21 </ b> A and a block-shaped continuous connection with the outer periphery of the lower portion of the main body 21 </ b> A. And a base 21B. The front end surface (left side in the drawing) of the base portion 21B and the front end surface of the main body portion 21A are located on the same plane, and the feeding pipe 3 is connected to the end surface. (See FIG. 1).

An end surface 21C on the rear side (right side in the drawing) of the base portion 21B protrudes to the rear side from an end surface 21D (tip portion) on the rear side of the main body portion 21A, and the other second member is formed by the upper surface of the protruding portion. A support portion 21 </ b> E that supports 22 is formed.
The main body portion 21A has a thick cylindrical portion 21Aa where the area near the front end surface is thick, and the rear portion is a large-diameter cylindrical portion 21Ab with a thinner thickness. Further, the main body portion 21A is formed with a first small-diameter tubular portion 21Ac extending from the rear end portion of the thick tubular portion 21Aa to the rear side. The large-diameter cylindrical portion 21Ab surrounds the first small-diameter cylindrical portion 21Ac and extends to the rear side by a predetermined dimension from there. The first small-diameter cylindrical portion 21Ac is formed in a cylindrical shape over the entire circumferential direction, and an axial cutout portion 7A that opens to the rear end 21Ad is formed at a required location in the circumferential direction. In addition, the first small-diameter cylindrical portion 21Ac is formed with notches 21Ae for the valve shaft 13 that open to the rear end 21Ad at two locations in the circumferential direction (FIGS. 1 and 3). reference).

On the other hand, a large diameter stepped hole 21Ba penetrating from the bottom portion to the inner peripheral surface of the large diameter cylindrical portion 21Ab of the main body portion 21A is formed in the base portion 21B provided continuously to the lower portion of the main body portion 21A. This stepped hole 21Ba constitutes the lower part of the gas introduction passage 4. An annular valve seat 12 is mounted in the stepped hole 21Ba. Further, the gas introduction pipe 15 is connected to surround the stepped hole 21Ba opened at the bottom of the base 21B (see FIG. 1).
The first member 21 is configured as described above, and the first member 21 configured as described above is manufactured using cast iron such as an aluminum alloy or FC200.

On the other hand, the second member 22 on the rear side includes a second small diameter cylindrical portion 22A located on the front side, and a flange portion extending radially outward from the outer peripheral portion of the rear side end portion of the second small diameter cylindrical portion 22A. 22B and an outer cylindrical portion 22C that continuously extends from the second small-diameter cylindrical portion 22A and the flange portion 22B to the rear side. The outer cylindrical portion 22C is provided to be inclined at a predetermined angle (18 ° in this embodiment) with respect to the axis of the second small-diameter cylindrical portion 22A.
The second small diameter cylindrical portion 22A is formed in the same manner as the first small diameter cylindrical portion 21Ac of the first member 21. That is, the outer diameter, inner diameter, and thickness of the second small diameter cylindrical portion 22A are set to the same dimensions as the outer diameter, inner diameter, and thickness of the first small diameter cylindrical portion 21Ac of the first member 21. The second small-diameter cylindrical portion 22A is formed with a notch 7A that opens at the front end 22Aa at a position facing the notch 7A of the other first small-diameter cylindrical portion 21Ac. ing. Further, two notches 22Ab for the valve shaft 13 are formed in the second small-diameter cylindrical portion 22A of the second member 22 (see FIGS. 1 and 3).
The axial dimension L1 of the second small-diameter cylindrical portion 22A of the second member 22 is from the axial dimension L2 of the large-diameter cylindrical portion 21Ab of the first member 21 that is the counterpart material to the axial direction of the first small-diameter cylindrical portion 21Ac. The dimension is set slightly shorter than the length obtained by subtracting the dimension L3. In other words, the axial lengths of the second small-diameter cylindrical portions 22A and 21Ac are set so that the length obtained by adding L1 and L3 is slightly shorter than the length of L2.
The second member 21 is configured as described above, and the second member 21 is manufactured using a cast iron such as an aluminum alloy or FC200 as a material.

And if the said 1st member 21 and the 2nd member 22 which have the structure mentioned above are cast separately, they are connected in an axial direction after that. That is, the second small-diameter cylindrical portion 22A of the second member 22 is inserted into the large-diameter cylindrical portion 21Ab of the first member 21 from the rear side, and the front end face of the flange portion 22B is used as the large-diameter cylindrical portion 21Ab. It is made to contact | abut to end surface 21D (front-end | tip part) of the rear side (refer FIG. 1, FIG. 4). At the same time, the lower end portion of the flange portion 22B is placed on the support portion 21E of the first member 21. Thus, the first member 21 and the second member 22 are positioned in the axial direction and the circumferential direction, and both the members 21 and 22 are integrally connected. Moreover, the axial center of both the members 21 and 22 is located on the same axis. That is, the state shown in FIG. 1 is obtained.
In this connected state, the end 21Ad on the rear side of the first small-diameter cylindrical portion 21Ac and the end 22Aa on the front side of the second small-diameter cylindrical portion 22A are slightly separated to form a gap g. In the state, the first small-diameter cylindrical portions 21Ac and 22A are arranged in series in the axial direction (see FIGS. 1 and 3). That is, the above-described inner partition wall 7 is configured by the first small-diameter cylindrical portions 21Ac and 22A, and the shaft center of both the members 21 and 22 positioned on the same axis is the axis C1 of the inner partition wall 7. As described above, the mixing chamber 11 is formed on the inner side of the inner partition wall 7. Further, the outer peripheral passage 10 is formed between the outer peripheral surfaces of the first small-diameter cylindrical portion 21Ac and the second small-diameter cylindrical portion 22A and the inner peripheral surface of the large-diameter cylindrical portion 21Ab of the first member 21. Further, the cutout portions 7A of the first small-diameter cylindrical portion 21Ac and the second small-diameter cylindrical portion 22A are positioned in series in the axial direction with the gap g interposed therebetween, and these first small-diameter cylindrical portion 21Ac and The notch 7A as the opening of the internal partition wall 7 described above is constituted by the notch 7A of the second small diameter cylindrical portion 22A.
Further, the outside air introduction pipe 6 is configured by the outer cylindrical portion 22 </ b> C of the second member 22. The outside air introduction pipe 6 is formed to be inclined at a predetermined angle θ (18 ° in this embodiment) with respect to the axis C1 of the internal partition wall 7. Then, at the position where the extension line of the axis C2 of the outside air introduction pipe 6 composed of the outer cylindrical portion 22C intersects the inner partition wall 7 (first small diameter cylindrical portion 21Ac, second small diameter cylindrical portion 22A), A notch 7A is formed.
In other words, the notch 7A formed in the internal partition wall 7 is formed at a location where the flow rate of the outside air G2 becomes maximum when fresh outside air G2 is introduced into the mixing chamber 11 from the outside air introduction pipe 6. .

  As described above, in the gas introducing device 1 of the present embodiment, the housing 2 is divided into the first member 21 on the front side and the second member 22 on the rear side, which are separately cast and then integrated in the axial direction. It is supposed to be connected to. Therefore, in this embodiment, compared with the case where the entire housing 2 having a complicated structure is cast as a single body, the casting work such as the production of the mold is simplified, and the manufacture of the gas introduction device 1 is simplified. It can be done easily.

Next, FIGS. 7 to 10 show a second embodiment of the present invention. In the second embodiment, substantially half of the inner partition wall 7 of the first embodiment in the circumferential direction is cut out to form a semi-cylindrical shape, and the notch portion 7A of the inner partition wall 7 is omitted. Therefore, in the second embodiment, the internal partition wall 107 is formed only substantially below the virtual horizontal plane passing through the axis C1. That is, the first small-diameter cylindrical portion 121Ac of the first member 121 and the second small-diameter cylindrical portion 122A of the second member 122 that form the internal partition wall 107 are formed in a semi-cylindrical shape with a U-shaped cross section in the orthogonal direction. Yes. A space portion on the lower side adjacent to the inner partition wall 107 serves as the outer peripheral passage 110, and the inside of the inner partition wall 107 (the space above the inner partition wall 107) serves as the mixing chamber 111. In the second embodiment, the notch corresponding to the notch 7A of the first embodiment is not formed in the internal partition wall 107. In the second embodiment, a notch portion that is adjacent to the circumferential direction of the semi-cylindrical inner partition wall 107 becomes an opening, and the outer peripheral passage 110 and the mixing chamber 111 communicate with each other through the opening. The other configurations are the same as those of the first embodiment. In the second embodiment, the members corresponding to those of the first embodiment are given numbers obtained by adding 100.
Also in the second embodiment, the housing 102 and the outside air introduction pipe 106 can be formed by casting the first member 121 and the second member 122 separately and then connecting them together in the axial direction. Therefore, the gas introducing device 101 can be easily manufactured according to the second embodiment as compared with the case where the housing 102 having a complicated internal configuration is cast as a single product.
In the second embodiment, since the upper half of the inner partition wall 107 is a semi-cylindrical shape, the EGR gas G1 introduced into the gas introduction passage 104 from the lower side is the outer periphery of the inner partition wall 107. Along the surface, the inside of the outer peripheral passage 110 rises from both the left and right sides and is introduced into the mixing chamber 111, and in this state, is mixed with the outside air G 2 in the mixing chamber 111. Therefore, also in the second embodiment, the EGR gas G1 and the outside air G2 can be efficiently mixed in the mixing chamber 111.

  In the first embodiment shown in FIGS. 1 to 4, an axial gap g is formed between the first small-diameter cylindrical portion 21Ac and the second small-diameter cylindrical portion 22A in the entire circumferential direction. However, the gap g is eliminated and the rear end 21Ad of the first small-diameter cylindrical portion 21Ac and the front end 22Aa of the second small-diameter cylindrical portion 22A are brought into contact with each other. Also good. This concept can be similarly adopted in the second embodiment shown in FIGS.

DESCRIPTION OF SYMBOLS 1 ... Gas introduction device 2 ... Housing 2A ... Outlet 6 ... Outside air introduction passage 7 ... Internal partition 7A ... Notch (opening)
DESCRIPTION OF SYMBOLS 10 ... Outer passage 11 ... Mixing chamber 15 ... Gas introduction pipe G1 ... EGR gas G2 ... Outside air G3 ... Mixed gas C1 ... Axis center of internal partition 7 C2 ... Axis center of outside air introduction pipe 6

Claims (5)

A housing having an internal space, a cylindrical internal partition wall provided in the housing and dividing the internal space of the housing into an inner mixing chamber and an outer peripheral passage, and formed in the internal partition wall An opening that communicates the mixing chamber and the outer peripheral passage, an outside air introduction pipe that is inclined with respect to the axis of the inner partition wall and is connected to the housing to introduce outside air into the mixing chamber, and the housing A gas introduction pipe which is connected and introduces gas into the mixing chamber through the outer peripheral passage and the opening; and an outlet which discharges the mixed gas of the outside air and the gas mixed in the mixing chamber to the outside of the housing. With
The outside air is introduced into the mixing chamber through the outside air introducing pipe and the gas is introduced from the gas introducing pipe through the outer peripheral passage and the opening to the mixing chamber, and the outside air and the gas are mixed in the mixing chamber and then mixed. In the gas introduction device configured to discharge the gas from the outlet,
2. A gas introducing apparatus according to claim 1, wherein a notch as the opening is formed at a position where an extension line of the axis of the outside air introduction tube intersects the internal partition.   The gas introduction device according to claim 1, wherein the inner peripheral portion of the internal partition and the inner peripheral portion of the outside air introduction pipe are formed continuously.   The gas introduction device according to claim 2 or 3, wherein the notch is formed in a long hole shape along the axial direction of the internal partition.   The inner partition wall is formed with a circumferential gap continuously from the notch to the entire circumferential area or a part thereof, and the circumferential gap also constitutes a part of the opening. The gas introduction device according to any one of claims 1 to 3, wherein:   The gas introduction device according to any one of claims 1 to 4, wherein the gas is an EGR gas.