JP2016017407A - Exhaust mixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent formation of condensate by suppressing cooling of exhaust gas mixed with intake air during cold time.SOLUTION: An exhaust mixing device 19 introduces exhaust gas to intake air flowing through an intake passage so as to mix the intake air with the exhaust gas. The exhaust mixing device 19 includes an exhaust annular passage 55 annularly provided on an outer periphery of the intake passage so that the exhaust gas flows therethrough, an exhaust introduction passage 57 for introducing the exhaust gas to the exhaust annular passage 55, an exhaust introduction hole 59 provided on a passage wall 53 between the intake passage and the exhaust annular passage 55 and introducing the exhaust gas to a converging part 58 of the intake air and the exhaust gas which is constituted by an inner side of the passage wall 53, and a hot water passage 62 provided adjacently to the exhaust annular passage 55 so that hot water flows therethrough. A wall surface of the passage wall 53 on the side of the exhaust annular passage 55 is formed of metal, and a wall surface on the side of the converging part 58 is formed of a resin layer 61. A passage cross sectional area of the converging part 58 is set to be larger than a passage cross sectional area of the intake passage on the upstream side and the downstream side of the converging part 58. The exhaust introduction hole 59 is formed on the passage wall 53 so that the exhaust gas is introduced at right angles with respect to the flow of the intake air in the converging part 58.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an exhaust gas mixing device that introduces exhaust gas into intake air flowing through an intake passage to mix intake air and exhaust gas.

  Conventionally, as this type of technology, for example, an exhaust gas recirculation device described in Patent Document 1 below is known. This device is provided with a first passage through which exhaust gas flows to the side wall of the vaporizer. One end of the first passage opens into the intake passage between the venturi portion of the carburetor and the throttle valve, and the other end opens upstream of the carburetor. In addition, the intake manifold is provided with a second passage that has one end communicating with the exhaust passage of the engine and the lower end opening of the carburetor in the first passage. Further, the intake manifold is provided with an air passage having one end opened in the first passage and the other end opened in the intake passage upstream of the atmosphere or the venturi portion of the carburetor. And a cylindrical pipe | tube is mounted | worn with the 1st channel | path provided in the side wall of a vaporizer | carburetor through a heat insulation layer. This prevents deposits from accumulating in the first passage.

Japanese Utility Model Publication No. 53-128420

  However, in the apparatus described in Patent Document 1, when cold air flows through the carburetor during the cold, moisture in the exhaust gas may be condensed in the first passage to generate condensed water. When condensed water is generated in this way, there is a risk that the piping of the passage will rust.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an exhaust mixing device capable of preventing the generation of condensed water by suppressing the cooling of exhaust mixed with intake air when cold. It is to provide.

  In order to achieve the above object, an invention according to claim 1 is an exhaust gas mixing device that introduces exhaust gas into the intake air flowing through the intake passage and mixes the intake air and the exhaust gas, and is provided annularly on the outer periphery of the intake passage. The exhaust passage through which the exhaust flows, the exhaust introduction passage for introducing exhaust gas into the exhaust circulation passage, and the passage wall between the intake passage and the exhaust circulation passage are arranged inside the passage wall between the intake air and the exhaust. The merging portion is provided with an exhaust introduction hole for introducing exhaust gas into the merging portion, and a hot water passage provided adjacent to the exhaust circulation passage through which hot water flows, and a passage wall on the side of the exhaust circulation passage. It is intended that the wall surface is formed of a heat conductive material, and the wall surface on the side of the merging portion is formed of a heat insulating material.

  According to the configuration of the above invention, the exhaust gas flowing from the exhaust gas introduction path to the exhaust gas circulation path is introduced into the merging portion through the plurality of exhaust gas introduction holes and mixed with the intake air. Here, the wall of the passage is formed of a heat conductive material on the side of the exhaust ring and the wall of the side of the junction is formed of a heat insulating material. Therefore, even if low-temperature intake air flows through the junction, The inside of the road is hard to be cooled. In addition, since the hot water passage is provided adjacent to the exhaust circulation path, the exhaust circulation passage is warmed early by the hot water flowing through the warm water passage, and cooling of the exhaust gas when the exhaust gas starts flowing through the exhaust circulation passage is suppressed.

  In order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the passage cross-sectional area of the merging portion is greater than the passage cross-sectional area of the intake passage upstream and downstream of the merging portion. The purpose is that the exhaust introduction hole is formed in the passage wall so that the exhaust is introduced at a right angle or an angle close to a right angle with respect to the flow of the intake air at the junction.

  According to the configuration of the invention, in addition to the operation of the invention according to claim 1, the passage cross-sectional area of the merging portion is set larger than the passage cross-sectional area of the intake passage on the upstream side and the downstream side of the merging portion. The flow velocity of the intake air at the merging portion is reduced, and the exhaust gas is introduced at a right angle or an angle close to the right angle with respect to the intake air flow at the merging portion, so that the flow of the exhaust gas is directed toward the center of the intake air flow.

  In order to achieve the above object, according to a third aspect of the present invention, in the second aspect of the present invention, in the exhaust circulation path, a rectifying wall for regulating the flow of the exhaust around the exhaust introduction hole is provided. Is intended to be formed.

  According to the configuration of the invention described above, in addition to the operation of the invention according to claim 2, the flow of exhaust gas is more strongly directed by the rectifying wall toward the center of the flow of intake air at the junction. In addition, since the rectifying wall is located in the exhaust ring, the rectifying wall does not reduce the pressure loss at the junction.

  In order to achieve the above object, according to a fourth aspect of the present invention, there is provided an exhaust control valve for adjusting an exhaust flow at an inlet of the exhaust introduction passage in the invention according to any one of the first to third aspects. And an intake air introduction path for introducing intake air from the intake passage is connected between the merging portion and the exhaust control valve.

  According to the configuration of the invention described above, in addition to the operation of the invention according to any one of claims 1 to 3, even if the exhaust gas leaks from the exhaust control valve to the exhaust gas introduction path in the cold state, the leaked exhaust gas is Since it is diluted by the intake air introduced into the exhaust gas through the introduction path, the moisture ratio in the exhaust gas is reduced.

  According to the first aspect of the present invention, it is possible to suppress the cooling of the exhaust gas mixed with the intake air when cold, thereby preventing the generation of condensed water.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the flow velocity of the intake air at the junction can be reduced, and the mixing of the intake air and the exhaust at the junction is effective. Can be a thing.

  According to the third aspect of the invention, in addition to the effect of the second aspect of the invention, the mixing of the intake air and the exhaust gas can be made more effective, and an increase in pressure loss at the junction is prevented. can do.

  According to the invention described in claim 4, in addition to the effects of the invention described in any one of claims 1 to 3, it is possible to reduce the humidity in the exhaust, and in that sense, the junction, the exhaust circuit, and the exhaust The effect of preventing the generation of condensed water in the introduction path can be improved.

The schematic block diagram which shows the gasoline engine system with a supercharger which concerns on one Embodiment and contains a low pressure loop type EGR apparatus. The front view which concerns on one Embodiment and shows an exhaust-gas mixing apparatus. The left view which concerns on one Embodiment and shows an exhaust-gas mixing apparatus. The right view which concerns on one Embodiment and shows an exhaust-gas mixing apparatus. FIG. 3 is a cross-sectional view taken along line AA of FIG. 2 showing the exhaust gas mixing apparatus according to the embodiment. The expanded sectional view which shows the part of the channel | path wall of an exhaust-gas mixing apparatus concerning one Embodiment. The BB sectional drawing of FIG. 2 which concerns on one Embodiment and shows an exhaust-gas mixing apparatus. The CC sectional view taken on the line of FIG. 3 which shows an exhaust-gas mixing apparatus concerning one Embodiment.

  Hereinafter, an embodiment in which an exhaust gas mixing device according to the present invention is embodied as an exhaust gas recirculation device for an engine will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing a supercharged gasoline engine system including a low-pressure loop exhaust gas recirculation device (low-pressure loop EGR device) in this embodiment. This engine system includes a reciprocating engine 1. An intake passage 3 is connected to the intake port 2 of the engine 1, and an exhaust passage 5 is connected to the exhaust port 4. An air cleaner 6 is provided at the inlet of the intake passage 3. A supercharger 7 for boosting the intake air in the intake passage 3 is provided in the intake passage 3 downstream of the air cleaner 6 between the exhaust passage 5 and the intake passage 3.

  The supercharger 7 includes a compressor 8 disposed in the intake passage 3, a turbine 9 disposed in the exhaust passage 5, and a rotating shaft 10 that connects the compressor 8 and the turbine 9 so as to be integrally rotatable. The supercharger 7 rotates the turbine 9 by the exhaust gas flowing through the exhaust passage 5 and integrally rotates the compressor 8 via the rotary shaft 10 to boost the intake air in the intake passage 3, that is, perform supercharging. It is like that.

  An exhaust bypass passage 11 that bypasses the turbine 9 is provided in the exhaust passage 5 adjacent to the supercharger 7. A waste gate valve 12 is provided in the exhaust bypass passage 11. By adjusting the exhaust gas flowing through the exhaust bypass passage 11 by the waste gate valve 12, the exhaust gas flow rate supplied to the turbine 9 is adjusted, the rotational speeds of the turbine 9 and the compressor 8 are adjusted, and supercharging by the supercharger 7 is performed. The pressure is adjusted.

  In the intake passage 3, an intercooler 13 is provided between the compressor 8 and the engine 1. The intercooler 13 cools intake air that has been pressurized by the compressor 8 to a high temperature to an appropriate temperature. A surge tank 3 a is provided in the intake passage 3 between the intercooler 13 and the engine 1. An electronic throttle device 14 which is an electric throttle valve is provided in the intake passage 3 downstream from the intercooler 13 and upstream from the surge tank 3a. The electronic throttle device 14 detects a butterfly throttle valve 21 disposed in the intake passage 3, a DC motor 22 for opening and closing the throttle valve 21, and an opening (throttle opening) of the throttle valve 21. The throttle sensor 23 is provided. The electronic throttle device 14 is configured such that the opening degree of the throttle valve 21 is adjusted by the throttle valve 21 being opened and closed by a DC motor 22 in accordance with the operation of an accelerator pedal (not shown) by the driver. . The exhaust passage 5 downstream of the turbine 9 is provided with a catalytic converter 15 having an exhaust catalyst for purifying exhaust gas.

  The engine 1 is provided with an injector 25 for injecting and supplying fuel to the combustion chamber 16. Fuel is supplied to the injector 25 from a fuel tank (not shown). The engine 1 is provided with a spark plug 29 corresponding to each cylinder. Each spark plug 29 is ignited by receiving a high voltage output from the igniter 30. The ignition timing of each spark plug 29 is determined by the high voltage output timing from the igniter 30. The spark plug 29 and the igniter 30 constitute an ignition device.

  In this embodiment, the engine 1 is provided with a low-pressure loop EGR device. The EGR device includes an exhaust gas recirculation passage (EGR passage) 17 for flowing a part of the exhaust gas discharged from the combustion chamber 16 of the engine 1 into the exhaust passage 5 as EGR gas to the intake passage 3 and returning it to the combustion chamber 16; An exhaust gas recirculation valve (EGR valve) 18 for adjusting the flow of EGR gas in the passage 17 is provided. The EGR passage 17 is provided between the exhaust passage 5 downstream from the catalytic converter 15 and the intake passage 3 upstream from the compressor 8. That is, the EGR passage 17 has an inlet connected to the exhaust passage 5 downstream from the turbine 9 and the catalytic converter 15, and an outlet connected to the intake passage 3 upstream from the compressor 8 via the EGR valve 18 and the exhaust mixing device 19. Is done. The EGR passage 17 is provided with an EGR cooler 20 for cooling the EGR gas flowing through the passage 17. The EGR valve 18 is disposed in the EGR passage 17 downstream from the EGR cooler 20.

  In this embodiment, the EGR valve 18 is configured as a poppet valve and as an electric valve. Moreover, in order to implement | achieve mass EGR, as for the EGR valve 18, the opening area of the valve seat 33 is expanded compared with the prior art, and the valve body 32 is enlarged according to it.

  According to the low-pressure loop EGR device described above, negative pressure is generated in the intake passage 3 upstream of the compressor 8 when the engine 1 is in operation and the supercharger 7 operates. At this time, when the EGR valve 18 is opened, a part of the exhaust discharged from the combustion chamber 16 to the exhaust passage 5 becomes EGR gas from the compressor 8 via the EGR passage 17, the EGR valve 18 and the exhaust mixing device 19. It flows to the upstream intake passage 3, further flows through the compressor 8 and the intake passage 3, and is returned to the combustion chamber 16. Here, the exhaust mixing device 19 is provided in the intake passage 3 in order to introduce EGR gas into the intake passage 3 through which intake air flows and to mix it effectively with intake air.

  Next, the configuration of the exhaust mixing device 19 will be described in detail. FIG. 2 is a front view of the exhaust mixing device 19. FIG. 3 is a left side view of the exhaust mixing device 19. FIG. 4 is a right side view of the exhaust mixing device 19. FIG. 5 shows the exhaust mixing device 19 by a cross-sectional view taken along line AA of FIG. FIG. 6 is an enlarged sectional view showing a portion of the passage wall 53 of the exhaust mixing device 19. FIG. 7 shows the exhaust mixing device 19 by a cross-sectional view taken along line BB in FIG. FIG. 8 shows the exhaust mixing device 19 by a cross-sectional view taken along the line CC of FIG.

  As shown in FIG. 2, the exhaust mixing device 19 includes two metal pipe blocks 31 and 32, and the pipe blocks 31 and 32 are fastened with bolts 33 to form a single unit. The two pipe blocks 31 and 32 are made of, for example, stainless steel or aluminum. 2 and 8, the first pipe block 31 positioned on the left side includes a first pipe 41 connected to the intake passage 3 and a first flange 42. The second pipe block 32 located on the right side includes a second pipe 51 connected to the intake passage 3 and a second flange 52. The two pipe blocks 31 and 32 are fastened by bolts 33 at the first flange 42 and the second flange 52. As shown in FIG. 8, a rubber packing 70 is provided between the first flange 42 and the second flange 52 for sealing. These two pipes 41 and 51 constitute a part of the intake passage 3 by being connected to the intake passage 3.

  As shown in FIG. 8, the second pipe block 32 has a double-pipe structure in the portion continuing to the upstream side of the second pipe 51. As shown in FIGS. 5 and 8, the inside of the double pipe is an annular passage wall 53 that constitutes the intake passage 3, and the outside of the double pipe is an annular ring that is disposed with a space from the passage wall 53. Of the outer peripheral wall 54. The second flange 52 is formed continuously on the outer peripheral wall 54. Between the passage wall 53 and the outer peripheral wall 54, an exhaust circulation passage 55 is formed in an annular shape through which EGR gas flows. 2 and 8, a third pipe 56 extending downward is formed on the lower side of the outer peripheral wall 54. Inside the third pipe 56 is an exhaust introduction passage 57 for introducing EGR gas into the exhaust circulation passage 55. An EGR valve 18 corresponding to an example of the exhaust control valve of the present invention is connected to the inlet of the exhaust introduction passage 57.

  As shown in FIGS. 5 and 8, the passage wall 53 has a plurality of (four) for introducing EGR gas into the merged portion 58, where the inside of the passage wall 53 is a merged portion 58 of intake air and EGR gas. The exhaust introduction holes 59 are provided at equiangular intervals. The passage sectional area of the merging portion 58 is set larger than the passage sectional area of the first pipe 41 that is the intake passage 3 upstream of the merging portion 58 and the second pipe 51 that is the intake passage 3 downstream. The plurality of exhaust introduction holes 59 are formed in the passage wall 53 so that the EGR gas is introduced at a right angle or an angle close to a right angle with respect to the flow of intake air at the merging portion 58. As shown in FIGS. 5 and 8, a rectifying wall 60 for adjusting the flow of EGR gas is formed around each exhaust introduction hole 59. The rectifying wall 60 is disposed in the exhaust circulation passage 55 and is formed to protrude outward in the radial direction of the passage wall 53.

  As shown in FIGS. 5, 6, and 8, the passage wall 53 is formed of a metal (the same material as the second pipe block 32), which is a heat conductive material, on the side of the exhaust circulation passage 55. The side wall surface is formed of a resin layer 61 that is a heat insulating material. That is, the wall surface of the passage wall 53 on the side of the merging portion 58 is covered with the resin layer 61 formed of a resin material. In this embodiment, as an example, when the thickness of the passage wall 53 is “1 to 2 (mm)”, the thickness of the resin layer 61 can be “1 (mm)”.

  As shown in FIGS. 7 and 8, the second pipe block 32 is provided with a hot water passage 62 through which hot water flows adjacent to the exhaust circulation passage 55. The hot water passage 62 is formed so as to surround the merging portion 58 in a U shape. As shown in FIGS. 2, 4, and 7, pipe joints 63 and 64 are provided at the inlet and the outlet of the hot water passage 62, respectively. These pipe joints 63 and 64 are connected to pipes (not shown) for flowing warm water (engine cooling water) warmed by the engine.

  As shown in FIGS. 2, 3, and 8, in order to introduce the intake air from the intake passage 3 into the exhaust introduction passage 57 between the junction 58 and the EGR valve 18 and immediately downstream of the EGR valve 18. An outlet 66a of an intake air introduction path 66 composed of the pipe 65 is connected. An inlet 66 b of the intake air introduction path 66 is connected in communication with the first pipe 41 of the first pipe block 31 so that intake air is introduced into the intake air introduction path 66.

  According to the exhaust mixing device 19 of this embodiment described above, the EGR gas flowing from the exhaust introduction passage 57 to the exhaust circulation passage 55 is introduced into the merging portion 58 through the plurality of exhaust introduction holes 59 and mixed with the intake air. Is done. Here, the passage wall 53 is formed of a metal that is a heat conduction material on the wall surface on the exhaust circulation passage 55 side, and is formed of a resin layer 61 that is a heat insulating material on the wall surface on the merge portion 58 side. Even if a low-temperature intake air flows through 58, the inside of the exhaust circulation passage 55 is not easily cooled. Further, since the hot water passage 62 is provided adjacent to the exhaust circulation passage 55, the exhaust circulation passage 55 is warmed early by the hot water flowing through the hot water passage 62, and the exhaust gas is cooled when the exhaust gas begins to flow through the exhaust circulation passage 55. It can be suppressed. For this reason, it is possible to suppress the cooling of the EGR gas mixed with the intake air when cold, thereby preventing the generation of condensed water.

  According to this embodiment, the passage sectional area of the merging portion 58 is set larger than the passage sectional areas of the intake passages (the first pipe 41 and the second pipe 51) on the upstream side and the downstream side of the merging portion 58. Since the flow velocity of the intake air at the merging portion 58 is reduced and the EGR gas is introduced at a right angle or an angle close to the right angle with respect to the intake air flow at the merging portion 58, the flow of the EGR gas toward the center of the intake air flow. Will be oriented. For this reason, the flow velocity of the intake air at the merging portion 58 can be reduced, and mixing of the intake air and the EGR gas in the merging portion 58 can be made effective.

  According to this embodiment, the flow of EGR gas is more strongly directed by the rectifying wall 60 toward the center of the flow of intake air at the merging portion 58. Further, since the rectifying wall 60 is located in the exhaust gas circulation line 55, the rectifying wall 60 does not reduce the pressure loss in the joining portion 58. For this reason, mixing of intake air and EGR gas can be made even more effective, and an increase in pressure loss at the merging portion 58 can be prevented.

  According to this embodiment, even if the EGR gas leaks from the EGR valve 18 to the exhaust introduction path 57 during the cold time, the leaked EGR gas is diluted by the intake air introduced into the EGR gas by the intake introduction path 66. Therefore, the moisture ratio in the EGR gas is reduced. For this reason, the humidity in the EGR gas can be reduced, and in this sense, the effect of preventing the generation of condensed water in the merging portion 58, the exhaust circulation passage 55, and the exhaust introduction passage 57 can be improved.

  In addition, this invention is not limited to the said embodiment, A part of structure can also be changed suitably and implemented in the range which does not deviate from the meaning of invention.

  (1) In the above-described embodiment, the passage cross-sectional area of the merging portion 58 is set larger than the passage cross-sectional areas of the upstream side and downstream side intake passages (the first pipe 41 and the second pipe 51) of the merging portion 58. It is also possible to set the passage sectional area of the merging portion and the passage sectional area of the intake passage upstream and downstream of the merging portion to be the same.

  (2) In the above embodiment, the exhaust introduction hole 59 is formed in the passage wall 53 so that the EGR gas is introduced at a right angle or an angle close to a right angle with respect to the flow of the intake air in the merge portion 58. The exhaust introduction hole may be formed in the passage wall so that the exhaust gas is introduced obliquely with respect to the flow.

  (3) In the above embodiment, the rectifying wall 60 for adjusting the flow of the EGR gas is formed around the exhaust introduction hole 59. However, the rectifying plate 60 may be omitted.

  (4) In the above-described embodiment, the intake air introduction passage 66 for introducing the intake air from the intake passage 3 is connected to the exhaust introduction passage 57 immediately downstream of the EGR valve 18. However, the intake air introduction passage 66 may be omitted. it can.

  (5) In the embodiment described above, the outlet 66a of the intake air introduction path 66 is connected to the exhaust gas introduction path 57 immediately downstream of the EGR valve 18. The connection position of the outlet 66a is between the junction 58 and the EGR valve 18. Any location can be used.

  (6) In the above embodiment, the inlet 66 b of the intake introduction path 66 is connected to the first pipe 41, but the inlet 66 b of the intake introduction path 66 is connected to the intake passage 3 at a position other than the exhaust mixing device 19. It can also be connected.

  The present invention can be used for an intake passage of a gasoline engine or a diesel engine, and can be used particularly for an engine equipped with an EGR device.

3 Intake passage 18 EGR valve (exhaust control valve)
19 Exhaust mixing device 41 1st pipe (intake passage)
51 Second pipe (intake passage)
53 Passage wall 55 Exhaust ring 57 Exhaust introduction path 58 Junction part 59 Exhaust introduction hole 60 Rectification wall 61 Resin layer (heat insulation material)
62 Hot water passage 65 Pipe 66 Air intake passage

According to this embodiment, the flow of EGR gas is more strongly directed by the rectifying wall 60 toward the center of the flow of intake air at the merging portion 58. Further, since the baffle wall 60 is located within the exhaust gas recirculation passage 55, never baffle wall 60 causes deleted loss of pressure in the combined unit 58. For this reason, mixing of intake air and EGR gas can be made even more effective, and an increase in pressure loss at the merging portion 58 can be prevented.

Claims (4)

An exhaust gas mixing device for introducing exhaust gas into intake air flowing through an intake passage to mix the intake air and the exhaust gas,
An exhaust ring provided annularly on the outer circumference of the intake passage, through which the exhaust flows;
An exhaust introduction path for introducing the exhaust into the exhaust ring;
The passage wall between the intake passage and the exhaust circulation path is provided with an exhaust introduction hole for introducing the exhaust into the junction where the inside of the passage wall serves as a junction of the intake and the exhaust. Being able to
A hot water passage provided adjacent to the exhaust ring and through which hot water flows;
The exhaust mixing device according to claim 1, wherein the passage wall includes a wall surface on the exhaust circulation side made of a heat conductive material and a wall surface on the merge portion side made of a heat insulating material.   A passage cross-sectional area of the merging portion is set to be larger than a passage cross-sectional area of the intake passage on the upstream side and the downstream side of the merging portion, and the exhaust is at a right angle or near a right angle with respect to the flow of the intake air in the merging portion. The exhaust mixing device according to claim 1, wherein the exhaust introduction hole is formed in the passage wall so as to be introduced at an angle.   The exhaust mixing device according to claim 2, wherein a rectifying wall for adjusting the flow of the exhaust is formed around the exhaust introduction hole in the exhaust circulation path. An exhaust control valve for adjusting the flow of the exhaust is provided at the inlet of the exhaust introduction path,
The exhaust gas mixture according to any one of claims 1 to 3, wherein an intake air introduction path for introducing the intake air from the intake passage is connected between the merging portion and the exhaust gas control valve. apparatus.

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