JP4450257B2 - Exhaust purification device - Google Patents

Description

  The present invention relates to an exhaust purification device that purifies exhaust gas discharged from an engine.

  In exhaust gas exhausted from engines mounted on automobiles, especially diesel engines, carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and particulate matter (PM) ) Etc. are included. For this reason, in general, for example, a three-way catalyst for decomposing (reducing, etc.) the pollutants and a particulate filter for capturing PM in an exhaust passage through which exhaust gas discharged from the engine passes. Etc., so that the exhaust gas is discharged into the atmosphere as harmless as possible.

  In such a particulate filter, since PM accumulates in the filter and the passage resistance increases with use, it is necessary to perform a regeneration process as necessary. As such regeneration processing, a heating device is provided in the particulate filter, and PM is burned and removed by heating. However, fuel (light oil) is added to the oxidation catalyst provided upstream of the particulate filter. A method is also proposed in which a hydrocarbon-based liquid such as) is introduced to cause an exothermic reaction and the particulate filter is regenerated by this heat.

  In diesel engines, nitrogen oxides (NOx) are particularly likely to be generated. For this reason, in order to efficiently decompose NOx in exhaust gas, many so-called NOx trap catalysts that decompose and reduce NOx by repeatedly adsorbing and reducing NOx, for example, are often used in diesel engines. ing.

  Such a NOx trap catalyst needs to appropriately supply a reducing agent from the outside to the NOx trap catalyst in order to decompose (reduce) the adsorbed NOx. For this reason, in general, fuel (light oil) or the like is supplied as a reducing agent into the exhaust passage so as to be supplied to the NOx trap catalyst. For example, there is one in which a NOx reducing agent is injected toward a NOx trap catalyst by an injector provided in an exhaust pipe (see, for example, Patent Document 1).

JP-A-2005-214100 JP 2004-044483 A

  Thus, in the configuration in which the reducing agent (additive) such as fuel is injected from the injector into the exhaust passage, the tip end surface of the injector is exposed in the exhaust passage and exposed to high-temperature exhaust gas. For this reason, there exists a possibility that the temperature of an injector may exceed the heat-resistant temperature and a burning may generate | occur | produce. Further, when the temperature of the injector rises, the volatile component of the fuel adhering to the tip surface evaporates and the remaining component is altered and deposited as a deposit. In addition, the reducing agent attached to the tip surface of the injector becomes a binder, soot in the exhaust gas adheres, and gradually accumulates as deposits. Then, this deposit may clog the injector nozzle, making it impossible to supply the reducing agent to the exhaust passage, which may cause a problem that the exhaust gas cannot be purified.

  In order to solve such a problem, for example, a water jacket (cooling water channel) is formed around the injector, and cooling water is introduced into the water jacket and circulated to suppress an increase in the temperature of the injector. There are some (see, for example, Patent Document 2).

  By providing the cooling water channel in this way, the temperature rise of the injector can be suppressed to some extent, but there is a possibility that the injector cannot be sufficiently cooled simply by providing the cooling water channel around the injector. It is desired.

  The present invention has been made in view of such circumstances, and is capable of effectively cooling an injector that injects an additive into an exhaust passage and purifying exhaust gas well over a long period of time. An object is to provide a purification device.

A first aspect of the present invention that solves the above-described problems includes an exhaust purification catalyst interposed in an exhaust passage communicating with an engine, and an upstream side of the exhaust purification catalyst that is added to the exhaust passage. An injector for injecting the agent, and a mounting member having a mounting hole in which the injector is mounted, and an annular cooling water passage through which cooling water is introduced is provided around the mounting hole of the mounting member, The cooling water passage is connected to a supply passage for supplying cooling water and a discharge passage for discharging cooling water, and at least the supply passage extends along a tangential direction of the cooling water passage. the near the connecting portion between the supply path of the cooling water channel, a protrusion portion of the side wall in the circumferential direction of the cooling water channel is projected to a position impinging the cooling water introduced from the supply passage, the projecting portion By waterway Sometimes the exhaust purification device according to claim width and a constriction portion narrowed is provided.

  In such a first aspect, the cooling water introduced from the supply path into the cooling water path collides with the protrusions to generate a turbulent flow, thereby increasing the cooling effect of the injector. Further, the cooling water passes through the constricted portion, whereby the flow velocity is increased, and this also increases the cooling effect of the injector. Thereby, the injector is sufficiently cooled, and deposit accumulation is suppressed. Therefore, the exhaust gas can be purified well over a long period.

  According to a second aspect of the present invention, there is provided the exhaust gas purification apparatus according to the first aspect, wherein the supply path and the discharge path are respectively connected to the same position in the circumferential direction of the cooling water path.

  In the second aspect, the cooling water introduced from the supply path into the cooling water path is discharged from the discharge path after at least one round of the cooling water path, so that the injector can be efficiently cooled. Further, in such a configuration, a part of the cooling water hitting the protrusion flows backward in the supply path, collides with the main flow that has passed through the narrowed portion, and further turbulence is generated. This turbulent flow further improves the cooling efficiency of the injector.

  According to a third aspect of the present invention, the injector is held by the mounting member and a fixing member fixed to the mounting member, and the projecting portion fixes the fixing member to the mounting member. The exhaust purification apparatus according to the first or second aspect is characterized in that it constitutes a boss portion to which the fastening member is fastened.

  In the third aspect, the mounting member can be reduced in size by effectively using the protruding portion.

  According to a fourth aspect of the present invention, there is provided the exhaust emission control device according to any one of claims 1 to 3, wherein the narrowed portion is provided over a height direction of the cooling water channel.

  In the fourth aspect, the speed of the main flow of the cooling water is more reliably increased, and the cooling water reliably hits the protruding portion to increase the turbulent flow strength. Thereby, an injector can be cooled more effectively.

  In such an exhaust purification device of the present invention, the injector for injecting the additive into the exhaust passage is effectively cooled, so that it is possible to suppress the occurrence of problems such as clogging of the injector due to deposit accumulation accompanying the temperature rise of the injector. Can do. Therefore, the exhaust gas can be purified well over a long period.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a diagram showing a schematic configuration of an exhaust emission control device according to the present embodiment. As shown in FIG. 1, the exhaust purification device 10 has a plurality of exhaust purification catalysts and exhaust purification filters, and the plurality of exhaust purification catalysts and exhaust purification filters are installed in a vehicle. An exhaust pipe (exhaust passage) 12 of a cylinder diesel engine (hereinafter simply referred to as an engine) 11 is interposed.

  The engine 11 includes a cylinder head 13 and a cylinder block 14, and a piston 16 is accommodated in each cylinder bore 15 of the cylinder block 14 so as to be reciprocally movable. A combustion chamber 17 is formed by the piston 16, the cylinder bore 15, and the cylinder head 13. The piston 16 is connected to a crankshaft 19 via a connecting rod 18 so that the crankshaft 19 is rotated by the reciprocating motion of the piston 16.

  An intake port 20 is formed in the cylinder head 13, and an intake pipe (intake passage) 22 including an intake manifold 21 is connected to the intake port 20. The intake port 20 is provided with an intake valve 23, and the intake port 20 is opened and closed by the intake valve 23. An exhaust port 24 is formed in the cylinder head 13, and an exhaust pipe (exhaust passage) 12 including an exhaust manifold 25 is connected to the exhaust port 24. The exhaust port 24 is provided with an exhaust valve 26. Like the intake port 20, the exhaust port 24 is opened and closed by the exhaust valve 26. A turbocharger 27 is provided in the middle of the intake pipe 22 and the exhaust pipe 12, and an exhaust purification catalyst and an exhaust purification catalyst that constitute the exhaust purification apparatus 10 are disposed downstream of the turbocharger 27 of the exhaust pipe 12. A filter is installed.

  The turbocharger 27 has a turbine (not shown) and a compressor connected to the turbine. When exhaust gas flows from the engine 11 into the turbocharger 27, the turbine is rotated by the flow of the exhaust gas, and the rotation of the turbine. Along with this, the compressor rotates to suck air from the intake pipe 22a into the turbocharger 27 and pressurize it. The air pressurized by the turbocharger 27 is supplied to each intake port 20 of the engine 11 through the intake pipe 22b.

  The cylinder head 13 is provided with an electronically controlled fuel injection valve 31 that directly injects fuel into the combustion chamber 17 of each cylinder. The fuel injection valve 31 has a predetermined fuel pressure from a common rail (not shown). Controlled high pressure fuel is supplied.

  Here, in the present embodiment, a diesel oxidation catalyst (hereinafter simply referred to as an oxidation catalyst) 32 and a NOx trap catalyst 33 which are exhaust purification catalysts, an exhaust purification filter, and an exhaust pipe 12 downstream of the turbocharger 27. A diesel particulate filter (DPF: Diesel Particulate Filter: hereinafter referred to as DPF) 34 is arranged in order from the upstream side. As will be described in detail later, an injector 50 for injecting fuel (light oil) as a reducing agent (additive) into the exhaust pipe 12a is provided in the exhaust pipe 12a between the turbocharger 27 and the oxidation catalyst 32. ing.

The oxidation catalyst 32 is formed, for example, by supporting a noble metal such as platinum (Pt) or palladium (Pd) on a honeycomb structure carrier made of a ceramic material. In the oxidation catalyst 32, when exhaust gas flows, nitrogen monoxide (NO) in the exhaust gas is oxidized to generate nitrogen dioxide (NO ₂ ). In addition, in order for the oxidation reaction in the oxidation catalyst 32 to occur, the oxidation catalyst 32 needs to be heated to a predetermined temperature or higher. Therefore, the oxidation catalyst 32 may be disposed as close to the engine 11 as possible. preferable. This is because the oxidation catalyst 32 is heated by the heat of the engine 11 and the oxidation catalyst 32 can be heated to a predetermined temperature or higher in a relatively short time even when the engine is started.

In the NOx trap catalyst 33, for example, a noble metal such as platinum (Pt) or palladium (Pd) is supported on a honeycomb structure carrier made of aluminum oxide (AL ₂ O ₃ ), and barium (Ba) or the like is used as a trapping agent. An alkali metal or alkaline earth metal is supported. The NOx trap catalyst 33 temporarily traps NOx in the oxidizing atmosphere, that is, NO ₂ generated by the oxidation catalyst 32, or NO remaining in the exhaust gas without being oxidized by the oxidation catalyst 32, for example, In a reducing atmosphere containing carbon (CO), hydrocarbon (HC), etc., NOx is released and reduced to nitrogen (N ₂ ) or the like.

Most of the NO ₂ produced by the oxidation catalyst 32 is adsorbed / decomposed (reduced) by the NOx trap catalyst 33, and the remaining NO _{2 that} has not been adsorbed / decomposed is purified by the reaction in the DPF 34. Yes.

  Normally, most of the exhaust gas discharged from the engine 11 is occupied by NO and the amount of HC is very small. Therefore, the inside of the NOx trap catalyst 33 becomes an oxidizing atmosphere, and the NOx trap catalyst 33 only adsorbs NOx. NOx that has been released is not decomposed (reduced). For this reason, when a predetermined amount of NOx is adsorbed to the NOx trap catalyst 33, fuel (light oil) as an additive is injected from the injector 50 fixed to the exhaust pipe 12 a between the turbocharger 27 and the oxidation catalyst 32. It has become so. As a result, the exhaust gas mixed with fuel passes through the oxidation catalyst 32 and is supplied to the NOx trap catalyst 33. The inside of the NOx trap catalyst 33 becomes a reducing atmosphere, and the adsorbed NOx is decomposed (reduced).

  The DPF 34 is, for example, a filter having a honeycomb structure formed of a ceramic material. In the DPF 34, an exhaust gas passage 38 having an upstream end opened and a downstream end closed, and a downstream end are provided. Exhaust gas passages 39 opened and closed at the upstream end are alternately arranged. The exhaust gas first flows into the exhaust gas passage 38 whose upstream end is opened, and the exhaust whose downstream end is opened from the porous wall surface provided between the adjacent exhaust gas passages 39. The gas flows into the gas passage 39 and flows downstream, and in this process, particulate matter (PM) in the exhaust gas collides with the wall surface or is adsorbed and captured.

The trapped PM is oxidized (combusted) by NO ₂ in the exhaust gas and discharged as CO ₂ , and NO ₂ remaining in the DPF 34 is decomposed into N ₂ and discharged. That is, the DPF 34 can purify the exhaust gas and greatly reduce PM and NOx emissions. Moreover, the performance of the DPF 34 is regenerated to some extent by burning PM.

Here, since NOx is normally adsorbed by the NOx trap catalyst 33 as described above, the amount of NO _{2 in} the exhaust gas supplied to the DPF 34 is small, and PM is gradually deposited on the DPF 34. When a predetermined amount of PM accumulates in the DPF 34, a predetermined amount of fuel is injected from the injector 50 fixed to the exhaust pipe 12a. As described above, when the fuel is mixed with the exhaust gas, the NOx trapped by the NOx trap catalyst 33 is reduced, so that NOx (NO ₂ ) contained in the exhaust gas is not absorbed by the NOx trap catalyst 33. To the DPF 34. As a result, PM combustion in the DPF 34 is promoted.

  An exhaust temperature sensor 40 is provided in the vicinity of the upstream side of the oxidation catalyst 32, the NOx trap catalyst 33 and the DPF 34, and in the vicinity of the downstream side of the DPF 34, respectively. The temperature of the exhaust gas flowing into the NOx trap catalyst 33 and the DPF 34 and the temperature of the exhaust gas discharged from the oxidation catalyst 32, the NOx trap catalyst 33 and the DPF 34 are detected. Further, an oxygen concentration sensor 41 for detecting the oxygen concentration in the exhaust gas is provided in the vicinity of the upstream side of the oxidation catalyst 32 and the DPF 34. The vehicle is provided with an electronic control unit (ECU) (not shown). The ECU includes an input / output device, a storage device for storing a control program and a control map, a central processing unit, a timer and a counter. There is a kind. The ECU performs comprehensive control of the engine 11 and the exhaust purification device 10 based on information from the sensors.

  2 is a cross-sectional view of the mounting member according to the present embodiment, FIG. 3 is a cross-sectional view taken along line AA ′ of FIG. 2, and FIG. 4 is a cross-sectional view taken along line BB ′ of FIG. As shown in FIGS. 2 to 4, the injector 50 for injecting fuel as a reducing agent (additive) is arranged in a direction substantially orthogonal to the exhaust pipe 12 a in this embodiment, and the exhaust pipe 12 a. Are held by a mounting member 60 fixed to the mounting member 60 and a fixing member 70 fixed to the mounting member 60.

  The mounting member 60 is formed with a mounting hole 61 which is a through hole into which the injector 50 is mounted at the center thereof. The injector 50 mounted in the mounting hole 61 is in a state where the tip surface 52 where the nozzle 51 opens is exposed in the exhaust pipe (exhaust passage) 12a, that is, in a state where the tip is exposed to the exhaust gas. The fixing member 70 is fixed to the mounting member 60. For example, in this embodiment, the fixing member 70 is fixed to the mounting member 60 by a fastening member 75 such as a bolt.

  The mounting member 60 is provided with an annular cooling water channel 62 around the mounting hole 61. A supply path 81 for supplying cooling water to the cooling water path 62 and a discharge path 91 for discharging cooling water circulated through the cooling water path 62 are connected to the cooling water path 62. That is, a supply pipe 80 having a supply path 81 and a discharge pipe 90 having a discharge path 91 are connected to the mounting member 60, and the supply path 81 (supply pipe 80) and the discharge path 91 (discharge pipe 90) are annular. The cooling water passage 62 extends in the tangential direction. In the present embodiment, the supply path 81 and the discharge path 91 are respectively connected to the same position in the circumferential direction of the cooling water path 62. In the axial direction of the mounting hole 61, the supply path 81 is more injector than the discharge path 91. 50 is arranged on the base end side.

  In such a configuration, the cooling water supplied from the supply path 81 circulates through the cooling water path 62 and is discharged from the discharge path 91, whereby the injector 50 is cooled. In the present embodiment, since the supply path 81 and the discharge path 91 are respectively connected to the same position in the circumferential direction of the cooling water path 62 as described above, the cooling water introduced from the supply path 81 to the cooling water path 62 is Since it is discharged from the discharge passage 91 after at least one round of the cooling water passage 62, the injector 50 can be efficiently cooled by the cooling water.

  Further, in the present invention, the width of the water channel is increased by the protruding portion 63 in which a part of the side wall of the cooling water channel 62 protrudes in the vicinity of the connection portion of the cooling water channel 62 with the supply channel 81, that is, in the vicinity of the outlet of the supply channel 81. Since the narrowed constricted portion 62a is provided, the injector 50 can be effectively cooled.

  As shown in FIG. 3, the protruding portion 63 according to the present embodiment is provided so as to protrude in a semicircular shape up to a position where a part of the side wall of the cooling water passage 62 collides with the cooling water introduced from the supply passage 81. And the narrow part 62a in which the width | variety of the cooling water channel 62 was narrowed by such a protrusion part 63 is formed. Further, in the present embodiment, the protruding portion 63 is provided so as to protrude only in a part in the depth direction of the cooling water passage 62 (the axial direction of the mounting hole 61), that is, only in a region facing the supply passage 81 (FIG. 2). ).

  In such a configuration, the cooling water introduced into the cooling water passage 62 from the supply passage 81 collides with the protrusion 63 and a turbulent flow is generated, so that the cooling effect of the injector 50 is improved. Specifically, as shown by arrows in FIG. 3, the flow of the cooling water is a main flow (forward flow) that passes through the constricted portion 62a and circulates through the cooling water channel 62. Further, a part of the cooling water hitting the protruding portion 63 flows backward and collides with the main flow that has passed through the narrowed portion 62a. Then, turbulent flow is generated by this collision, and the heat transfer coefficient of the portion where the turbulent flow is generated is improved. Further, since the cooling water passes through the constricted portion 62a, the flow velocity of the main flow increases, and accordingly, the turbulent flow intensity due to the collision increases, so that the heat transfer coefficient is further improved. Furthermore, the cooling effect in the narrowed portion 62a is enhanced by the increase in the flow rate of the cooling water in the narrowed portion 62a. Thereby, the injector 50 is cooled effectively. Therefore, occurrence of problems such as burning of the injector 50 or clogging of the nozzle 51 is suppressed, and the exhaust gas can be purified well over a long period of time.

  The position where the turbulent flow due to the collision of the cooling water occurs is preferably an area on the opposite side across the injector 50 of the constricted portion 62a. By generating turbulent flow at such a position, the injector 50 can be cooled more effectively. The position where the turbulent flow is generated in the cooling water channel 62 can be set to a desired position by adjusting the shape of the protruding portion 63, the protruding amount, and the like.

  In addition, if the turbulent flow can be generated at a desired position in this way, the protruding amount, shape, and the like of the protruding portion 63 are not particularly limited. For example, in the present embodiment, the protruding portion 63 is provided to protrude only in a region facing the supply path 81, but is not limited to this. For example, as shown in FIG. May be provided continuously.

  In the present embodiment, the protruding portion 63 is protruded in a substantially semicircular shape, and the end surface of the protruding portion 63 is configured by a curved surface. Thereby, the flow of the cooling water becomes relatively smooth. However, the end surface of the protruding portion 63 is not necessarily a curved surface. For example, as shown in FIG. 6, the protruding portion 63 may be formed so that the cross section has a substantially triangular shape, and the end surface thereof may be a flat surface.

  Furthermore, in the configuration in which the protrusion 63 is provided as described above, the width of the cooling water channel 62 is gradually changed before and after the constriction 62a. For example, as shown in FIG. An edge portion 63a may be provided in a portion opposite to the supply channel 81, and the width of the cooling water channel 62 in the wake of the narrowed portion 62a may be increased rapidly. In this case, as indicated by an arrow in FIG. 7, a flow (vortex) along the edge portion 63 a is generated on the downstream side of the protruding portion 63. The heat transferability is also improved by this cooling water flow (vortex), so that the injector 50 can be cooled more satisfactorily.

  Incidentally, the fixing member 70 for fixing the injector 50 is fixed to the mounting member 60 by the fastening member 75 as described above. And in this embodiment, the protrusion part 63 mentioned above comprises the boss | hub part which has the fastening hole 65 to which this fastening member 75 is fastened. Thus, by effectively using the protruding portion 63 provided on the mounting member 60 as a boss portion, it is not necessary to separately secure a region for providing the boss portion in the mounting member 60. That is, by providing the mounting member 60 with the protruding portion 63, there is an effect that the mounting member 60 can be downsized.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment. For example, in the above-described embodiment, the supply path 81 and the discharge path 91 are connected to the same position in the circumferential direction of the cooling water path 62, but of course, the present invention is not limited to this, and the supply path 81 and the discharge path 91 are The cooling water passage 62 may be connected to different positions in the circumferential direction. Furthermore, in the above-described embodiment, the configuration in which each of the supply path 81 and the discharge path 91 is extended along the tangential direction of the cooling water path 62 is exemplified, but at least the supply path 81 is along the tangential direction of the cooling water path 62. The extending direction of the discharge path 91 is not particularly limited.

  Further, for example, in the above-described embodiment, as the exhaust purification device 10, the exhaust pipe (exhaust passage) 12 includes the oxidation catalyst 32 and the NOx trap catalyst 33 that are exhaust purification catalysts, and the DPF 34 that is an exhaust purification filter. Although an example in which the oxidation catalyst 32, the NOx trap catalyst 33, and the DPF 34 are arranged in this order from the upstream side is given, the arrangement and types of the exhaust purification catalyst and the exhaust purification filter are not particularly limited. For example, as shown in FIG. 8A, the NOx trap catalyst 33, the oxidation catalyst 32, and the DPF 34 may be arranged in this order in the exhaust pipe 12 on the downstream side of the turbocharger 27. Further, for example, as shown in FIG. 8B, the NOx trap catalyst 33 and the DPF 34 may be sequentially arranged in the exhaust pipe 12 on the downstream side of the turbocharger 27 without providing the oxidation catalyst 32. . Further, for example, as shown in FIG. 8C, a configuration may be adopted in which only the DPF 34A having a catalytic function is provided without providing the exhaust purification catalyst. That is, only the DPF 34A, which is an exhaust purification filter that also serves as an exhaust purification catalyst, may be provided. In any case, the present invention can be adopted as long as it has an injector for injecting an additive such as fuel upstream of the exhaust purification catalyst or the exhaust purification filter.

  In the above-described embodiment, the NOx trap catalyst that decomposes (reduces) NOx using fuel (light oil) as a reducing agent is exemplified as the exhaust gas purification catalyst that decomposes (reduces) NOx, but is not limited thereto. For example, a so-called SCR (Selective Catalytic Reduction) that selectively adsorbs NOx in exhaust gas to a catalyst and injects ammonia or urea as a reducing agent from an injector to decompose (reduce) NOx may be used.

  In the above-described embodiment, the example in which the reducing agent is added as the additive has been described. However, the additive is not limited to the purpose of the reducing action, and if it is added to the exhaust system, for example, by combustion A fuel for the purpose of raising the temperature may be used.

  Furthermore, in the above-described embodiment, an example of the configuration of an intake / exhaust system including a turbocharger as a supercharger is shown. However, the present invention is not particularly limited thereto. For example, the supercharger is not necessarily provided. Further, a cooling exhaust gas recirculation device having a cooling exhaust gas recirculation passage between the exhaust passage and the intake passage, that is, a so-called EGR device may be provided.

It is a figure showing the schematic structure of the exhaust-air-purification device concerning one embodiment. It is sectional drawing of the mounting member with which the injector which concerns on one Embodiment is mounted | worn. It is sectional drawing of the mounting member with which the injector which concerns on one Embodiment is mounted | worn. It is sectional drawing of the mounting member with which the injector which concerns on one Embodiment is mounted | worn. It is sectional drawing which shows the modification of the mounting member which concerns on one Embodiment. It is sectional drawing which shows the modification of the mounting member which concerns on one Embodiment. It is sectional drawing which shows the modification of the mounting member which concerns on one Embodiment. It is a schematic block diagram which shows the modification of an exhaust gas purification apparatus.

Explanation of symbols

10 Exhaust purification device 11 Engine 12 Exhaust pipe (exhaust passage)
13 Cylinder Head 14 Cylinder Block 15 Cylinder Bore 16 Piston 17 Combustion Chamber 18 Connecting Rod 19 Crankshaft 20 Intake Port 21 Intake Manifold 22 Intake Pipe 23 Intake Valve 24 Exhaust Port 25 Exhaust Manifold 26 Exhaust Valve 27 Turbocharger 31 Fuel Injection Valve 32 Oxidation Catalyst 33 NOx trap catalyst 34 DPF
40 exhaust temperature sensor 41 oxygen concentration sensor 50 injector 51 nozzle 52 distal end surface 60 mounting member 61 mounting hole 62 cooling water path 62a constricted part 63 projecting part 63a edge part 65 fastening hole 70 fixing member 75 fastening member 81 supply path 91 discharge path

Claims (4)

An exhaust purification catalyst interposed in an exhaust passage communicating with the engine, an injector provided upstream of the exhaust purification catalyst and injecting an additive into the exhaust passage, and a mounting in which the injector is attached A mounting member having a hole,
An annular cooling water channel into which cooling water is introduced is provided around the mounting hole of the mounting member. The cooling water channel has a supply channel for supplying cooling water and a discharge channel for discharging the cooling water. Are connected to each other, and at least the supply channel extends along a tangential direction of the cooling water channel,
Wherein in the vicinity of the connecting portion between the supply path of the cooling water channel, a protrusion portion of the side wall in the circumferential direction of the cooling water channel is projected to a position impinging the cooling water introduced from the supply passage, the projecting portion exhaust gas purification apparatus characterized by a constriction width of the channel is narrowed is provided.   The exhaust purification apparatus according to claim 1, wherein the supply path and the discharge path are connected to the same position in the circumferential direction of the cooling water path.   The injector is held by the mounting member and a fixing member fixed to the mounting member, and the protruding portion has a boss portion to which a fastening member for fixing the fixing member to the mounting member is fastened. The exhaust emission control device according to claim 1, wherein the exhaust purification device is configured.   The exhaust purification apparatus according to any one of claims 1 to 3, wherein the narrowed portion is provided over a height direction of the cooling water channel.

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