JP2015010567A - Egr gas mixer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EGR gas mixer for allowing proper disassembly and easy internal cleaning when necessary.SOLUTION: An intake pipe 1 is detachably divided in the middle so that the inner diameter of an intake pipe 1B on the downstream side is relatively larger than the inner diameter of an intake pipe 1A on the further upstream side than the divided part. On the most upstream part of the intake pipe 1B on the downstream side, a cone-shaped venturi component 10 is arranged whose diameter is gradually enlarged toward the flowing direction of intake air 2 to make a flow path of the intake pipe 1A on the upstream side continuous with a flow path of the intake pipe 1B on the downstream side in a stepless manner. An annular chamber 11 is laid on the outer periphery of the venturi component 10. To the annular chamber 11, an EGR pipe 6 is connected which guides part of exhaust gas 5 removed from the exhaust side. Slits 12 are opened in a plurality of peripheral positions of the venturi component 10.

Description

  The present invention relates to an EGR gas mixing device.

  Conventionally, in an automobile engine or the like, a part of exhaust gas is extracted from the exhaust side and returned to the intake side, and combustion of fuel in the engine is suppressed by the exhaust gas returned to the intake side to lower the combustion temperature. So-called exhaust gas recirculation (EGR) is performed to reduce the generation of NOx. Generally, when performing this kind of exhaust gas recirculation, An appropriate position of the exhaust passage leading to the exhaust pipe and an intake pipe near the inlet of the intake manifold are connected by an EGR pipe, and the exhaust gas is recirculated through the EGR pipe.

  However, simply connecting the EGR pipe to the side surface of the intake pipe makes it difficult to uniformly mix the exhaust gas with the intake air flowing through the intake pipe. Furthermore, there is an opening at the connection portion of the EGR pipe to the intake pipe. Due to the narrowness, there is a disadvantage that the mixing ratio of the exhaust gas to the intake air cannot be increased rapidly.

  In order to improve such inconvenience, as shown in FIGS. 5 and 6, a venturi portion 3 for narrowing the flow of the intake air 2 is formed in the middle of the intake pipe 1, and an annular chamber 4 is provided on the outer periphery of the venturi portion 3. An EGR pipe 6 that extracts and guides a part of the exhaust gas 5 from the exhaust side is connected to the annular chamber 4, and an annular slit 7 that connects the annular chamber 4 and the inside of the intake pipe 1 is connected to the throat portion of the venturi 3. There has been proposed an EGR gas mixing device that is formed and divides the venturi portion 3 into an upstream reduced diameter portion 8 and a downstream expanded portion 9.

  That is, in this way, the exhaust gas 5 guided to the annular chamber 4 by the EGR pipe 6 flows into the intake pipe 1 from the entire circumference through the annular slit 7 formed in the venturi portion 3, and the venturi portion 3, the exhaust gas 5 in the annular chamber 4 is satisfactorily sucked by the negative pressure portion generated on the side of the expansion portion 9, so that a large amount of the exhaust gas 5 is mixed well with the intake air 2 in the intake pipe 1. Can be mixed gas.

  The same applicant as the present invention has also proposed that the region of the annular chamber 4 that is lower than the lowest level of the annular slit 7 is raised to the lowest level of the annular slit 7 (Patent Documents below). 1), in this way, even if the exhaust gas recirculated from the exhaust side to the intake side is condensed and condensed water is generated, a large amount of the condensed water is accumulated in the annular chamber 4. It won't happen.

Japanese Patent No. 5047924

  However, in such a conventional EGR gas mixing apparatus, the venturi portion 3 and the annular slit 7 are integrally formed by casting, so that cleaning is performed even if apportioning or the like accumulates in a narrow place in the interior. There was a problem that was difficult.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an EGR gas mixing apparatus that can be appropriately disassembled when necessary to easily clean the inside.

  The present invention divides the intake pipe halfway in a detachable manner, and configures the inner diameter of the downstream intake pipe to be relatively larger than the inner diameter of the intake pipe upstream from the divided portion. A cone-shaped venturi part is arranged in the upstream portion so that the diameter of the intake pipe gradually increases in the direction of the intake air flow so that the upstream intake pipe passage is continuous with the downstream intake pipe passage without any step. And an EGR pipe connected to the annular chamber for extracting and guiding a part of the exhaust gas from the exhaust side, and slits are opened at a plurality of locations in the circumferential direction of the venturi part. To do.

  Thus, in this way, the exhaust gas guided to the annular chamber by the EGR pipe flows through the slits of the venturi parts from a plurality of locations in the circumferential direction and flows into the intake pipe, Since the flow of intake air going straight from the intake pipe on the upstream side causes a pressure drop in the inner peripheral portion of the venturi part and the exhaust gas in the annular chamber is easily sucked into the venturi part, it has already been proposed. As in the conventional EGR gas mixing apparatus, a large amount of exhaust gas can be mixed well with the flow of intake air to form a mixed gas.

  In addition, the venturi structure for mixing the exhaust gas recirculated from the exhaust side into the intake air is made up of separate venturi parts, so when apportioning or the like accumulates, the upstream intake pipe and the downstream intake air It is possible to easily clean the inside of each intake pipe and the venturi parts by separating the pipes and taking out the venturi parts from the inside.

  In the present invention, a baffle plate is provided so as to extend from the upstream end of the slit toward the downstream side and gradually move away from the slit to the inside of the venturi part as it goes from the upstream side to the downstream side. The plate is preferably configured so that the flow of intake air does not go to the slit.

  In this way, even if a part of the intake air flowing in the venturi part forms a flow along the inner peripheral surface of the venturi part, particularly in an operation region where the flow velocity of the intake air is high, the intake air flow is directed to each slit. Therefore, the possibility that the exhaust gas is easily sucked and the ease of inhaling the exhaust gas is avoided.

  Furthermore, in the present invention, it is preferable to provide a guide fin for swirling the flow of intake air on one side of the baffle plate. The exhaust gas can be introduced into the swirling flow from a plurality of locations in the circumferential direction and effectively stirred.

  According to the EGR gas mixing device of the present invention, the following various excellent effects can be obtained.

  (I) According to the invention described in claim 1 of the present invention, the inside of the EGR gas mixing apparatus can be improved for a long period of time because it can be appropriately disassembled when necessary and the inside can be easily cleaned. Can be maintained, and labor during maintenance work can be greatly reduced.

  (II) According to the invention described in claim 2 of the present invention, a part of the intake air flowing through the venturi part forms a flow along the inner peripheral surface of the venturi part, particularly in an operation region where the flow velocity of the intake air is high. However, the baffle plate can divert the flow of the intake air so as not to go to the slits, so that it is possible to avoid the possibility that the exhaust gas is easily sucked.

  (III) According to the invention described in claim 3 of the present invention, the flow of the intake air can be swirled by the guide fin, and the effect of introducing the exhaust gas from a plurality of circumferential directions with respect to the swirl flow of the intake air is effective. Therefore, mixing of intake air and exhaust gas can be promoted significantly.

It is sectional drawing which looked at an example of the form which implements the present invention from the side. It is a single-piece figure of the venturi part of FIG. It is sectional drawing which shows the detail of the slit of FIG. It is a perspective view which shows another example of a form of this invention. It is sectional drawing which looked at the conventional example from the side. It is sectional drawing of the VI-VI arrow of FIG.

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

  FIG. 1 and FIG. 2 show an example of an embodiment for carrying out the present invention. In this embodiment, the intake pipe 1 is partly detachably divided, and the intake pipe 1A on the upstream side of the divided portion is separated. The inner diameter of the intake pipe 1B on the downstream side is relatively large with respect to the inner diameter, and the upstream intake pipe 1A and the downstream intake pipe 1B are connected to each other by flanges 1a and 1b provided at opposite ends. Are fastened to the most upstream portion of the intake pipe 1B on the downstream side, gradually toward the flow direction of the intake air 2 (the direction from right to left in FIG. 1). A cone-shaped venturi part 10 (see FIG. 2) is arranged to expand the diameter so that the flow path of the upstream intake pipe 1A is continuous with the flow path of the downstream intake pipe 1B without any step, and the venturi part 10 The flange 10a provided at the upstream end of the Intake pipe 1A, the flange 1a of 1B, by bolting in fastened in between the 1b each other are as fixed of the venturi part 10 can be reduced.

  Further, by arranging the venturi part 10 at the most upstream part of the intake pipe 1B on the downstream side, an annular chamber 11 is defined on the outer periphery of the venturi part 10, and the exhaust side of the annular chamber 11 is arranged on the exhaust side. The EGR pipe 6 that extracts and guides a part of the exhaust gas 5 from the exhaust pipe 5 is connected, and slits 12 are opened at a plurality of locations in the circumferential direction of the venturi part 10, and the annular chamber 11 passes through the slits 12. The exhaust gas 5 is introduced into the flow of the intake air 2 in the venturi part 10.

  Particularly in the present embodiment, the slit 12 in the venturi part 10 extends from the upstream end of the slit 12 toward the downstream side, and gradually slits from the upstream side toward the downstream side. A baffle plate 13 is provided so as to be separated from the inside of the venturi part 10 from 12, so that the flow of the intake air 2 does not go to the slit 12 by the baffle plate 13.

  That is, if such a baffle plate 13 is provided, a part of the intake air 2 flowing in the venturi part 10 forms a flow along the inner peripheral surface of the venturi part 10 particularly in an operation region where the flow velocity of the intake air 2 is high. However, the flow of the intake air 2 is diverted by the baffle plate 13 so as not to go to the respective slits 12, and the possibility that the exhaust gas 5 is easily sucked can be avoided.

  Here, when the venturi part 10 is made of a metal material, as shown in FIG. 3, the slit 12 is opened by making a cut in a portion corresponding to the slit 12 of the venturi part 10 and folding it inward. It is possible to use the baffle and the portion folded inward as the baffle plate 13. In this case, the depth of folding the baffle plate 13 inward is set to the downstream side of the flow path of the upstream intake pipe 1A. If it is set so shallow that it does not fall within the extended range (the range below the two-dot chain line in FIG. 3), it is possible to avoid an increase in intake resistance and obtain a good venturi effect.

  Thus, the exhaust gas 5 guided to the annular chamber 11 by the EGR pipe 6 is dispersed from a plurality of locations in the circumferential direction through the slits 12 of the venturi component 10 and flows into the intake pipe 1. In addition, a pressure drop occurs in the inner peripheral portion of the venturi component 10 due to the flow of the intake air 2 that is going to flow straight from the upstream intake pipe 1A, and the exhaust gas 5 in the annular chamber 11 is vented to the venturi component. 10 is easily sucked into the exhaust gas 10, so that a large amount of the exhaust gas 5 can be well mixed with the flow of the intake air 2 in the same manner as the conventional EGR gas mixing device already proposed. .

  In addition, since the venturi structure for mixing the exhaust gas 5 recirculated from the exhaust side into the intake air 2 is constituted by a separate venturi part 10, when apportioning or the like accumulates, It is possible to remove the venturi part 10 from the inside by separating the intake pipe 1B on the downstream side and easily clean the inside of each intake pipe 1 and the venturi part 10.

  Therefore, according to the above-described embodiment, the internal cleaning can be easily performed by appropriately disassembling when necessary, so that the soundness of the EGR gas mixing device can be maintained well over a long period of time, and maintenance work can be performed. The time labor can be greatly reduced, and a part of the intake air 2 flowing in the venturi part 10 forms a flow along the inner peripheral surface of the venturi part 10 particularly in an operation region where the flow velocity of the intake air 2 is high. However, the flow of the intake air 2 can be diverted by the baffle plate 13 so as not to go to the slits 12, and the possibility that the exhaust gas 5 is easily sucked can be avoided.

  FIG. 4 shows another embodiment of the present invention. When the venturi part 10 is molded from a resin material, the baffle plate 13 can be freely moved without being restricted by the opening shape of the slit 12. Since the guide fins 14 for turning the flow of the intake air 2 are attached to one side of the baffle plate 13, the intake air can be sucked by the guide fins 14. 2 is swirled, and the exhaust gas 5 can be introduced into the swirl flow of the intake air 2 from a plurality of locations in the circumferential direction to effectively stir, so that the mixing of the intake air 2 and the exhaust gas 5 is significantly promoted. can do.

  At this time, the portion of the guide fin 14 may be formed of a relatively soft resin different from the venturi part 10 and the baffle plate 13, and in this way, when the flow velocity of the intake air 2 is high, the guide fin 14. By bending and escaping, the flow of the intake air 2 is not forcedly blocked and an excessive increase in intake resistance can be avoided.

  In addition, the EGR gas mixing apparatus of this invention is not limited only to the above-mentioned example, Of course, various changes can be added within the range which does not deviate from the summary of this invention.

Reference Signs List 1 intake pipe 1A upstream intake pipe 1B downstream intake pipe 2 intake 5 exhaust gas 6 EGR pipe 10 venturi parts 11 annular chamber 12 slit 13 baffle plate 14 guide fin

Claims (3)

  The middle of the intake pipe is detachably divided, and the inner diameter of the intake pipe on the downstream side is relatively larger than the inner diameter of the intake pipe on the upstream side of the divided part, and the intake air is drawn into the most upstream part of the intake pipe on the downstream side. A cone-shaped venturi part is arranged to gradually increase the diameter in the flow direction so that the flow path of the upstream intake pipe is continuous with the flow path of the downstream intake pipe without any step, and annular around the venturi part EGR gas mixing characterized by partitioning the chamber, connecting an EGR pipe for extracting and guiding a part of the exhaust gas from the exhaust side to the annular chamber, and opening slits in a plurality of circumferential directions of the venturi parts apparatus.   A baffle plate is provided so as to extend from the upstream end of the slit toward the downstream side and gradually move away from the slit to the inside of the venturi part from the upstream side to the downstream side, and the flow of intake air is slit by the baffle plate. The EGR gas mixing device according to claim 1, wherein the EGR gas mixing device is configured so as not to go to the center.   3. The EGR gas mixing device according to claim 2, wherein a guide fin for imparting a swirl to the flow of the intake air is attached to one side portion of the baffle plate.

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