JP2013256912A - Filter device of exhaust reflux device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter device of an exhaust gas reflux device, configured to remove foreign matter in an EGR gas without increasing a pressure loss in an EGR passage, and to protect a filtering part from deterioration caused by exhaust-condensed water.SOLUTION: A filter device of an exhaust gas reflux device comprises: a capacity chamber 31 interposed in the middle of a low-pressure EGR passage 26 and having a liquified pool 34 at its bottom; a first connector 35 for making the upstream side of the low-pressure EGR passage 26 communicate with the capacity chamber 31; a second connector 36 for making the downstream side of the low-pressure EGR passage 26 communicate with the capacity chamber 31; and a cylindrical filter 40 having a filtering part 40a at its periphery. The filter 40 is connected to the second connector 36 in a position in which the filter is offset toward an upper part of the liquified pool 34 in the capacity chamber 31.

Description

  The present invention relates to a filter device for an exhaust gas recirculation device interposed in an EGR passage that recirculates a part of exhaust gas branched from an exhaust passage to an intake passage.

  Conventionally, in an engine exhaust gas recirculation device (EGR device), a part of the exhaust gas branched from the exhaust passage downstream of the catalytic converter is recirculated as EGR gas to the intake passage upstream of the compressor. A low pressure EGR device (LP-EGR device) is known. Such a low pressure EGR device can perform a large amount of EGR in the supercharging region by introducing EGR gas into the intake air before being pressurized by the compressor.

  On the other hand, in this type of low-pressure EGR device, there is a risk that foreign matter composed of carbon coagulation and the like mixed in EGR gas may be refluxed upstream of the compressor, and for protecting the compressor from such foreign matter. Countermeasures are required. Therefore, for example, as disclosed in Patent Document 1, in the low-pressure EGR device, a filter device for collecting a solidified substance or the like is interposed in the EGR passage. In this case, generally, a mesh member in which a fine metal wire is knitted is used as the filtering part of the filter device, and this filtering part is interposed so as to cross the entire opening of the pipeline in the middle of the EGR passage.

JP-A-5-187329

  By the way, the exhaust gas (EGR gas) flowing through the exhaust passage and the EGR passage may be cooled and condensed by the EGR cooler and the intercooler to generate exhaust condensed water.

  For example, if exhaust condensate is generated in the EGR passage and adheres to the filtration portion of the filter device, the effective area of the filtration portion may be reduced and pressure loss in the EGR passage may be increased. Further, when a large amount of exhaust condensed water is generated in the EGR passage, there is a possibility that a part of the filtering part is immersed in the exhaust condensed water. Here, the exhaust condensate has a high acidity, and if a filtration part composed of thin metal wires is repeatedly immersed in such exhaust condensate, there is a risk of premature deterioration due to corrosion or the like.

  The present invention has been made in view of the above circumstances, and can remove foreign matters contained in the EGR gas without increasing the pressure loss in the EGR passage, and can protect the filtration unit from deterioration due to exhaust condensed water. It aims at providing the filter apparatus of an exhaust-gas recirculation apparatus.

  A filter device of an exhaust gas recirculation device according to an aspect of the present invention includes a volume chamber having a liquid reservoir at the bottom interposed in the middle of an EGR passage that recirculates part of the exhaust gas in the exhaust passage to the intake passage, A cylindrical filter having a first communication portion that communicates the upstream side of the EGR passage with the volume chamber, a second communication portion that communicates the downstream side of the EGR passage with the volume chamber, and a filtration portion at the peripheral portion The filter is connected to the second communication part at a position offset upward from the liquid reservoir in the volume chamber.

  According to the filter device of the exhaust gas recirculation device of the present invention, it is possible to remove foreign substances contained in the EGR gas without increasing the pressure loss in the EGR passage, and to protect the filtration unit from deterioration due to exhaust condensed water. it can.

Schematic configuration diagram of the engine Side view showing main parts of exhaust passage and EGR passage piping Disassembled perspective view of filter disposed in filter device Vertical section of filter device Cross-sectional view along line VV in FIG. Longitudinal sectional view showing a modification of the filter device Cross-sectional view along line VII-VII in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of an engine, FIG. 2 is a side view showing a main part of piping of an exhaust passage and an EGR passage, and FIG. 3 is a filter disposed in a filter device. 4 is an exploded perspective view, FIG. 4 is a longitudinal sectional view of the filter device, and FIG. 5 is a transverse sectional view taken along line VV of FIG.

  An engine 1 shown in FIG. 1 is, for example, a diesel engine with a supercharger mounted on a vehicle such as an automobile. In the present embodiment, a horizontally opposed four-cylinder engine is shown. Cylinder heads 3 are crowned on both the left and right banks of the cylinder block 2 of the engine 1, and each cylinder head 3 has an intake port 3a and an exhaust port 3b for each cylinder.

  Each intake port 3 a is gathered in an air chamber 6 via an intake manifold 5. An intake passage 8 is connected to the upstream side of the air chamber 6 via a throttle body 7 incorporating an electronically controlled throttle valve 7a, for example. An intercooler 9 is interposed in the intake passage 8, and a compressor 10 a of the turbocharger 10 is interposed on the upstream side of the intercooler 9. Further, an air cleaner 11 is connected to the intake passage 8.

  On the other hand, the exhaust ports 3 b are gathered downstream via the exhaust manifold 15 and connected to the exhaust passage 16. A turbine 10b of the turbocharger 10 is interposed in the exhaust passage 16, and a diesel particulate filter (DPF: Diesel Particulate Filter) 17 is interposed downstream of the turbine 10b. Further, a muffler 18 is interposed in the exhaust passage 16 on the downstream side of the DPF 17. Here, as is well known, the DPF 17 is composed of PM (particulate matter: particulate matter = mainly black smoke (SOOT), unburned fuel and lubricant components called SOF, sulfate, (Including components generated from the sulfur content in light oil fuel called)) to suppress these emissions into the atmosphere.

  In such an intake and exhaust system of the engine 1, a high-pressure exhaust gas recirculation device (high-pressure EGR device) that recirculates a part of the exhaust gas discharged from each cylinder to the exhaust passage 16 downstream from the compressor 10a. 20 and a low-pressure exhaust gas recirculation device (low-pressure EGR device) 25 that recirculates upstream of the compressor 10a.

  The high pressure EGR device 20 includes, for example, a high pressure EGR passage 21 that communicates the exhaust passage 16 upstream of the turbine 10b and the downstream side of the throttle valve 7a. The high pressure EGR passage 21 is provided with a high pressure EGR control valve 22 that controls the flow rate of exhaust gas (EGR gas) that recirculates as EGR gas through the high pressure EGR passage 21, and an EGR cooler 23 that cools the EGR gas. ing.

  The low pressure EGR device 25 includes, for example, a low pressure EGR passage 26 that connects the exhaust passage 16 downstream of the DPF 17 and the intake passage 8 upstream of the compressor 10a. The low pressure EGR passage 26 is provided with a low pressure EGR control valve 27 that controls the flow rate of exhaust gas (EGR gas) that recirculates as EGR gas through the low pressure EGR passage 26, and an EGR cooler 28 that cools the EGR gas. ing. Further, on the low pressure EGR passage 26, a filter device 30 is interposed on the upstream side of the EGR cooler 28.

  As shown in FIGS. 2, 4, and 5, the filter device 30 has a volume chamber 31 interposed in the middle of the low pressure EGR passage 26. In the present embodiment, the volume chamber 31 is made of, for example, a highly corrosion-resistant stainless alloy or the like, and includes a first case half body 32 positioned on the upstream side with respect to the flow direction of the EGR gas, and a downstream side. And the second case half 33 located at the center.

  As shown in FIG. 2, a first connector portion 35 as a first communication portion is provided at the upstream end portion of the first case half 32, and the low pressure EGR passage is provided in the first connector portion 35. An upstream pipe 26a of 26 is connected. On the other hand, a second connector portion 36 as a second communication portion is provided at the downstream end portion of the second case half body 33, and the second connector portion 36 is provided on the downstream side of the low pressure EGR passage 26. The pipe 26b is connected.

  The first and second case halves 32 and 33 are formed, for example, at the opening end formed at the downstream end of the first case half 32 and the upstream end of the second case half 33. The open end portion thus formed is fitted to each other and welded to form a hollow volume chamber 31 communicating with the middle of the EGR passage 26.

  Here, for example, as shown in FIG. 4, the bottom of the volume chamber 31 is set as a liquid reservoir 34, and this liquid reservoir 34 is formed when exhaust condensed water flows into the volume chamber 31 together with the EGR gas. In addition, the exhaust condensed water can be stored.

  Further, the first connector portion 35 is disposed at a position biased downward in the upstream end portion of the first case half 32. As a result, the pipe 26a on the upstream side of the EGR passage 26 is communicated with the bottom of the piping 26a at substantially the same height as the bottom of the volume chamber 31, and the exhaust condensed water stored in the liquid reservoir 34 is accelerated when the vehicle travels. Therefore, it can be easily discharged to the exhaust passage 16 side.

  On the other hand, the second connector portion 36 is disposed at a position offset upward from the first connector portion 35 (for example, a position offset by about 20 to 25 mm above the first connector portion 35). Thereby, the piping 26b on the downstream side of the EGR passage 26 is communicated at a position offset upward from the liquid reservoir 34, and the inflow of the exhaust condensed water to the downstream side (EGR cooler 28 side) is prohibited.

  In the volume chamber 31, a filter 40 is provided for collecting foreign substances made of carbon coagulum mixed in the EGR gas. For example, as shown in FIG. 3 to FIG. 5, the filter 40 includes a cylindrical filter body 41, a filter medium 42 wound around the outer periphery of the filter body 41, and a distal end portion of the filter body 41. The lid body 43 is configured to be configured.

  More specifically, the filter body 41 is formed of a cylindrical sheet metal member made of, for example, a highly corrosion-resistant stainless alloy, and a plurality of vent holes 41a are formed in the periphery of the filter body 41 by punching or the like. It is open. In this case, for example, by setting the length of the filter main body 41 to a sufficient length with respect to the pipe diameter of the pipe 26b of the EGR passage 26, the total opening area by each vent hole 41a is the opening of the pipe 26b. It is set to be sufficiently larger than the area.

  The filter medium 42 is configured by a mesh-like member knitted with a metal thread made of, for example, a highly corrosion-resistant stainless alloy having a wire diameter of about 0.1 mm. Then, the filter medium 42 is wound around the outer peripheral surface of the filter body 41 and covers the vent hole 41 a, thereby forming a filter part 40 a on the peripheral part of the filter body 41.

  In addition, the lid body 43 is made of a disk-shaped member made of, for example, a highly corrosion-resistant stainless alloy or the like. The lid 43 closes the tip of the filter body 41 by being fitted and welded to the inner periphery of the tip of the filter body 41.

  The filter 40 configured as described above is held in the volume chamber 31 by, for example, connecting the base end portion of the filter main body 41 to the second connector portion 36. At this time, as described above, the second connector portion 36 is set at a position spaced above the bottom surface of the volume chamber 31 by a predetermined height, so that the filter 40 is located above the liquid reservoir portion 34. It is disposed in the volume chamber 31 at a position offset to.

  In such a configuration, when EGR gas flows into the volume chamber 31 from the pipe 26 a on the upstream side of the EGR passage 26, the EGR gas flows downstream through the filtration unit 40 a provided in the peripheral portion of the filter 40. To the side pipe 26b. At that time, foreign matter such as carbon coagulum mixed in the EGR gas is collected in the filtration part 40a.

  Further, even when the exhaust gas condensate is contained in the EGR gas, most of the exhaust gas condensate is dropped before the EGR gas passes through the filtering unit 40 a and stored in the liquid storage unit 34. That is, the filter 40 has a configuration in which the tip portion facing the first connector portion 35 is closed by the lid body 43, and the filtration portion 40a is set only in the cylindrical peripheral portion. It flows into the filtration part 40a while wrapping around the periphery, and most of the exhaust condensed water contained in the EGR gas is efficiently separated into gas and liquid and dropped into the liquid storage part 34 due to the turbulence of the airflow in the process. Is done.

  Further, even if the exhaust condensate that remains without being dropped is dropped in the filtering part 40a, the total opening area of the filtering part 40a (vent hole 41a) is sufficiently larger than the opening area of the pipe 26b. Therefore, the pressure loss in the filtration part 40a is suppressed.

  Furthermore, since the filter 40 is offset upward with respect to the liquid reservoir 34, the filter 40 is not immersed in the exhaust condensed water stored in the liquid reservoir 34, and the filter 40 a is filtered by the exhaust condensed water. A significant reduction in the effective area, early deterioration of the filtration unit 40a, and the like are suppressed.

  According to such an embodiment, the volume chamber 31 having the liquid reservoir portion 34 interposed in the middle of the low pressure EGR passage 26 and the first connector communicating the upstream side of the low pressure EGR passage 26 with the volume chamber 31. Part 35, a second connector part 36 communicating with the volume chamber 31 on the downstream side of the low-pressure EGR passage 26, and a cylindrical filter 40 having a filtration part 40 a on the peripheral part. By connecting to the second connector portion 36 at a position offset upward from the liquid reservoir portion 34 in the inside, the foreign matter contained in the EGR gas is removed without increasing the pressure loss in the EGR passage 26. The filtration part 40a can be protected from deterioration due to the exhaust condensed water.

  In addition, this invention is not limited to each embodiment described above, A various deformation | transformation and change are possible, and they are also in the technical scope of this invention. For example, in the above-described embodiment, an example in which the volume chamber 31 is configured using the first and second case halves 32 and 33 divided in the front and rear direction with respect to the flow direction of the EGR gas has been described. The present invention is not limited to this. For example, as shown in FIGS. 6 and 7, the first and second case halves 50 and 51 divided into two along the flow direction of the EGR gas are flange-joined. The volume chamber 31 can also be configured.

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Cylinder block 3 ... Cylinder head 3a ... Intake port 3b ... Exhaust port 5 ... Intake manifold 6 ... Air chamber 7 ... Throttle body 7a ... Throttle valve 8 ... Intake passage 9 ... Intercooler 10 ... Turbocharger 10a Compressor 10b Turbine 11 Air cleaner 15 Exhaust manifold 16 Exhaust passage 17 Diesel particulate filter 18 Muffler 20 High pressure exhaust gas recirculation device 21 High pressure EGR passage 22 High pressure EGR control valve 23 EGR cooler 25 Low pressure Exhaust gas recirculation device 26 ... low pressure EGR passage 26a ... piping 26b ... piping 27 ... low pressure EGR control valve 28 ... EGR cooler 30 ... filter device 31 ... volume chamber 32 ... first case half 33 ... second Case half 34 ... liquid reservoir 35 ... first connector portion (first communicating section)
36 ... 2nd connector part (2nd communication part)
DESCRIPTION OF SYMBOLS 40 ... Filter 40a ... Filtration part 41 ... Filter main body 41a ... Air hole 42 ... Filter medium 43 ... Lid 50 ... 1st case half 51 ... 2nd case half

Claims (2)

A volume chamber having a liquid reservoir at the bottom and interposed in the middle of the EGR passage for returning a part of the exhaust gas in the exhaust passage to the intake passage;
A first communication portion that communicates the upstream side of the EGR passage with the volume chamber;
A second communication portion that communicates the downstream side of the EGR passage to the volume chamber;
A cylindrical filter having a filtration part on the periphery,
The filter device for an exhaust gas recirculation device, wherein the filter is connected to the second communication portion at a position offset upward from the liquid reservoir in the volume chamber.   2. The filter device for an exhaust gas recirculation apparatus according to claim 1, wherein the second communication portion is set at a position offset upward from the first communication portion.

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