JP2009013806A - Exhaust emission control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine, having high mountability and high conversion performance. <P>SOLUTION: This exhaust emission control device for the internal combustion engine includes an exhaust passage 100, a catalyst 230, and an injector 300 injecting urea water toward the catalyst 230. The exhaust passage 100 has a catalyst storage portion 160 storing the catalyst 230, a pipe portion 140 positioned forward of a vehicle with respect to the catalyst storage portion 160, and a cone portion 150 provided to taperingly enlarge the width of the exhaust passage 100 from the pipe portion 140 toward the catalyst storage portion 160. The catalyst storage portion 160, pipe portion 140 and cone portion 150 are linearly formed in a direction where exhaust gas flows (direction of arrow DR1). The pipe portion 140 is arranged in a position decentered from the catalyst storage portion 160. The injector 300 injects the urea water from a direction where the pipe portion 140 is decentered from the catalyst storage portion 160 toward the catalyst 230 stored in the catalyst storage portion 160. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust gas purification apparatus for an internal combustion engine, and more particularly to an exhaust gas purification apparatus for an internal combustion engine that purifies exhaust gas from the internal combustion engine.

2. Description of the Related Art An exhaust gas purification device for an internal combustion engine that purifies exhaust gas from the internal combustion engine is conventionally known.
For example, Japanese Patent Application Laid-Open No. 2004-197635 (Patent Document 1) describes an exhaust emission control device in which a fuel addition injector is attached to the outside in a bending direction of a bent portion upstream from an exhaust emission control catalyst.

  Similarly, JP-A-2005-127260 (Patent Document 2), JP-A-2005-76460 (Patent Document 3), JP-A-2006-77691 (Patent Document 4) and JP-A-2004-11463 ( Patent Document 5) describes an exhaust purification device in which an exhaust pipe is bent and an injector is attached to the bent portion.

Japanese Patent Laying-Open No. 2005-290993 (Patent Document 6) describes that part of the exhaust pipe is eccentric with respect to other parts.
JP 2004-197635 A JP 2005-127260 A JP-A-2005-76460 JP 2006-77691 A JP 2004-11463 A JP-A-2005-290993

  As described above, when the reducing agent is supplied from the injector into the exhaust pipe, it is required to uniformly supply the reducing agent injected from the injector to the exhaust purification catalyst in the exhaust pipe from the viewpoint of improving the purification performance.

  On the other hand, when the exhaust purification device as described above is mounted on a vehicle, it is necessary to provide an exhaust pipe through which exhaust gas flows while avoiding interference with other members. On the other hand, due to restrictions on the installation position of the exhaust purification catalyst, the installation position of the injector that supplies the reducing agent to the catalyst is also restricted. Under such circumstances, if a structure that bends the exhaust pipe of the injector mounting portion as in Patent Documents 1 to 5, it may be difficult to dispose the exhaust pipe.

  In addition, in the exhaust gas purification apparatus described in Patent Document 6, the position where the injector is attached is not described. Therefore, even in this apparatus, sufficient mountability and purification performance cannot always be achieved.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an exhaust purification device for an internal combustion engine having high mountability and purification performance.

  An exhaust purification device for an internal combustion engine according to the present invention includes an exhaust passage through which exhaust gas from an internal combustion engine mounted on a vehicle flows, an exhaust purification catalyst provided in the exhaust passage, and a reduction toward the exhaust purification catalyst. And an injector for injecting the agent. The exhaust passage includes a first part that houses the exhaust purification catalyst, a second part that is located upstream of the first part and that has a smaller width than the first part, and a second part to a first part. And a cone portion provided so as to increase the width of the exhaust passage in a tapered shape. The first portion, the second portion, and the cone portion are formed so as to be linearly arranged in the direction in which the exhaust gas flows, and the second portion is provided at a position that is eccentric with respect to the first portion. The injector is attached to the second part, and injects the reducing agent toward the exhaust purification catalyst housed in the first part from the direction in which the second part is eccentric with respect to the first part.

  According to the above configuration, by arranging the first portion, the second portion, and the cone portion so as to be linearly arranged in the direction in which the exhaust gas flows, the number of curved portions of the exhaust passage is reduced, and the exhaust purification device Mountability on the vehicle is improved. On the other hand, the second part is provided at a position eccentric to the first part, and the reducing agent is directed from the direction in which the second part is eccentric to the first part toward the exhaust purification catalyst housed in the first part. , It becomes easier to inject the reducing agent toward the center of the exhaust gas purification catalyst. As a result, the reducing agent is dispersed in a wider range of the exhaust purification catalyst, and the exhaust purification performance is improved. As described above, according to the present invention, an exhaust purification device having high mountability on a vehicle and high exhaust purification performance can be obtained.

  In the exhaust gas purification apparatus for an internal combustion engine, preferably, the second part is provided at a position eccentric to the outer side in the vehicle width direction with respect to the first part.

  According to the said structure, since an injector can be arrange | positioned in the position near the vehicle outer side where the flow of cooling air is good, the cooling performance of an injector can be improved.

  The exhaust gas purification apparatus for an internal combustion engine preferably further includes a bracket that is attached to a side frame provided so as to extend in the front-rear direction of the vehicle and supports the second portion.

  According to the above configuration, the second portion eccentric to the outer side in the width direction of the vehicle is supported by the bracket with respect to the first portion. Therefore, the arm length of the bracket is reduced, and the mass of the parts constituting the bracket is reduced. The increase can be suppressed.

  In the exhaust gas purification apparatus for an internal combustion engine, preferably, the bracket is provided so as to support a portion of the second portion to which the injector is attached from below.

  According to the said structure, it becomes possible to protect an injector from the flying object from below, such as a flying stone, with the bracket provided under the 2nd part of the exhaust passage.

  According to the present invention, in the exhaust gas purification apparatus for an internal combustion engine, both mountability and purification performance can be achieved.

  Embodiments of the present invention will be described below. Note that the same or corresponding portions are denoted by the same reference numerals, and the description thereof may not be repeated.

  Note that in the embodiments described below, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like unless otherwise specified. In the following embodiments, each component is not necessarily essential for the present invention unless otherwise specified. In addition, when there are a plurality of embodiments below, it is planned from the beginning to appropriately combine the configurations of the embodiments unless otherwise specified.

  FIG. 1 is a schematic top view showing the configuration of an exhaust gas purification apparatus for an internal combustion engine according to one embodiment of the present invention.

  Referring to FIG. 1, an exhaust purification device according to the present embodiment is a purification device for purifying exhaust gas from engine 1 mounted on a vehicle and then exhausting the exhaust gas. The exhaust passage 100 that flows in the direction of the arrow DR1, the catalysts 210, 220, and 230 provided in the exhaust passage 100, and an injector 300 that injects a reducing agent into the exhaust passage 100 are configured.

  The exhaust passage 100 includes catalyst storage portions 110 and 120, a cone portion 130, a pipe portion 140, a cone portion 150, and a catalyst storage portion 160. The catalyst storage sections 110 and 120, the cone section 130, the pipe section 140, the cone section 150, and the catalyst storage section 160 are arranged from the front side (left side in FIG. 1) to the rear side (right side in FIG. 1). They are arranged in order.

  Catalysts 210, 220, and 230 are stored in the catalyst storage units 110, 120, and 130, respectively. The cone part 130 is formed so as to narrow the width of the exhaust passage 100 in a tapered shape from the front to the rear of the vehicle. The cone part 130 has an asymmetric shape with respect to the longitudinal axis of the vehicle. The pipe part 140 is supported by a bracket 500 attached to the side frame 400 of the vehicle. The cone portion 150 provided between the pipe portion 140 and the catalyst storage portion 160 is formed so as to increase the width of the exhaust passage 100 in a tapered shape from the front to the rear of the vehicle. The cone portion 150 has an asymmetric shape with respect to the longitudinal axis of the vehicle. Exhaust gas that has passed through the catalyst 230 stored in the catalyst storage unit 160 flows in the direction of the arrow OUT and flows out of the vehicle.

  The exhaust purification apparatus according to the present embodiment can be applied to, for example, an exhaust purification apparatus that reduces NOx (nitrogen oxide) contained in exhaust gas of a diesel engine. The injector 300 injects urea water 600 toward the catalyst 230. Based on information from an engine control unit (not shown), an exhaust gas temperature sensor (not shown), etc., a dosing control unit (not shown) calculates a target addition amount of the urea water 600, Air is mixed and injected from the injector 300 into the exhaust passage 100.

  The process of reducing nitrogen oxides in the exhaust gas (reducing nitrogen oxides to nitrogen) is described as follows.

The urea water 600 injected into the exhaust passage 100 is decomposed into ammonia and carbon dioxide in the catalyst housing 160, which is a catalyst-integrated muffler [Formula (1)].
CO (NH ₂ ) ₂ + H ₂ O → 2NH ₃ + CO ₂ ... (1)
Next, ammonia generated by decomposition from the urea water 600 chemically reacts with nitrogen oxides contained in the exhaust gas from the engine 1 to be decomposed into water and nitrogen [formula (2)].
2NH ₃ + NO + NO ₂ → 2N ₂ + 3H ₂ O (2)
As the catalyst 230, for example, a catalyst containing silicon can be used. In addition, fuel such as gasoline may be supplied to the catalyst 230 instead of the urea water 600 described above.

  The exhaust emission control device according to the present embodiment has one characteristic in the structure around the pipe part 140, the cone part 150, and the catalyst storage part 160.

  As shown in FIG. 1, the pipe part 140, the cone part 150, and the catalyst storage part 160 are formed so as to be arranged in a straight line in the direction in which the exhaust gas flows (the longitudinal direction of the vehicle). Further, the center 140C in the width direction of the pipe portion 140 is located on the outer side in the width direction of the vehicle with respect to the center 160C in the width direction of the catalyst storage portion 160. That is, the pipe part 140 is provided at a position eccentric to the outer side in the width direction with respect to the catalyst housing part 160. And the injector 300 attached to the pipe part 140 is inject | pouring the urea water 600 toward the catalyst 230 from the width direction outer side of a vehicle.

  In recent years, regulations regarding vehicle exhaust gas have become more stringent, and therefore, the catalyst provided in the exhaust passage tends to increase in size and the number of installed catalysts tends to increase. Therefore, there is a high need for improving the mountability of the exhaust purification device on a vehicle. On the other hand, from the viewpoint of improving the exhaust purification performance, it is necessary to distribute and supply the urea water 600 injected from the injector 300 in a wider range of the catalyst 230.

  According to the exhaust gas purification apparatus according to the present embodiment, as described above, the pipe section 140, the cone section 150, and the catalyst storage section 160 are arranged in a straight line in the front-rear direction of the vehicle. The number of 100 curved portions is reduced, and the mountability of the exhaust purification device on a vehicle can be improved. On the other hand, the pipe part 140 is provided at a position that is eccentric with respect to the catalyst storage unit 160, and the urea water 600 is injected from the eccentric side toward the catalyst 230 stored in the catalyst storage unit 160, thereby It becomes easy to inject the urea water 600 toward the center in the width direction. As a result, the urea water 600 is dispersed in a wider range of the catalyst 230, and the exhaust purification performance is improved.

  Further, as shown in FIG. 1, by providing the pipe portion 140 at a position eccentric to the outside in the width direction of the vehicle with respect to the catalyst housing portion 160, the injector 300 is positioned close to the outside of the vehicle where the flow of cooling air is good. Since it can arrange | position, the cooling performance of the injector 300 can be improved.

  In addition, since the pipe portion 140 eccentric to the outer side in the vehicle width direction with respect to the catalyst housing portion 160 is supported by the bracket 500 attached to the side frame 400 positioned at the width direction end portion of the vehicle, The arm length can be reduced, and an increase in the mass of the parts constituting the bracket 500 can be suppressed.

  2 is a cross-sectional view taken along the line II-II in FIG. Referring to FIG. 2, a bracket 500 that supports the pipe part 140 includes an arm 510 that is fixed to the side frame 400, a spacer 520 that is attached to the arm 510, and a spacer 520 that supports the pipe part 140. And a pedestal 530.

  As shown in FIG. 2, the bracket 500 is provided so as to support the pipe portion 140 from below. By doing so, the bracket 500 can be positioned below the injector 300 attached to the pipe portion 140. Therefore, it is possible to protect the injector 300 from flying stones when the vehicle is traveling.

  As a modification of the structure of the exhaust passage 100 located around the catalyst 230, for example, those shown in FIGS.

  In the example of FIG. 3, the center 140C in the width direction of the pipe portion 140 is shifted to the outside in the width direction of the vehicle relative to the center 160C in the width direction of the catalyst storage portion 160, but compared with the example of FIG. The center 140C in the width direction 140 is slightly shifted inward in the width direction of the vehicle.

  In the example of FIG. 4, the axial center 140 </ b> C of the pipe part 140 is shifted to the inner side in the vehicle width direction than the axial center 160 </ b> C of the catalyst storage part 160. In such a case, although the arm length of the bracket 500 that supports the pipe portion 140 becomes long, the urea water 600 is installed in the same manner as the example of FIG. 1 by attaching the injector 300 to the inside of the pipe portion 140 in the vehicle width direction. Can be easily supplied toward the center of the catalyst 230 in the width direction.

  The above contents are summarized as follows. That is, the exhaust gas purification apparatus for an internal combustion engine according to the present embodiment includes an exhaust passage 100 through which exhaust gas from the engine 1 that is an “internal combustion engine” flows, and an “exhaust purification catalyst” provided in the exhaust passage 100. And an injector 300 that injects urea water 600 that is a “reducing agent” toward the catalyst 230. The exhaust passage 100 is located on the upstream side (front side of the vehicle) with respect to the catalyst storage unit 160 as a “first portion” that stores the catalyst 230 and is narrower than the catalyst storage unit 160. The pipe portion 140 as the “second portion” and the cone portion 150 provided so as to increase the width of the exhaust passage 100 in a tapered shape from the pipe portion 140 toward the catalyst housing portion 160. The catalyst storage unit 160, the pipe unit 140, and the cone unit 150 are formed so as to be linearly arranged in the direction in which the exhaust gas flows (arrow DR1 direction), and the pipe unit 140 is eccentric with respect to the catalyst storage unit 160. It is provided in the position to do. The injector 300 is attached to the pipe portion 140, and urea water is directed from the direction in which the pipe portion 140 is eccentric to the catalyst storage portion 160 (that is, the upper side in FIG. 1) toward the catalyst 230 stored in the catalyst storage portion 160. Inject 600.

  Although the embodiments of the present invention have been described above, the embodiments disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic top view showing a configuration of an exhaust gas purification apparatus for an internal combustion engine according to one embodiment of the present invention. It is II-II sectional drawing in FIG. FIG. 3 is a view showing one modification of the structure around the exhaust purification catalyst in the exhaust purification apparatus shown in FIG. 1. FIG. 7 is a view showing another modification of the structure around the exhaust purification catalyst in the exhaust purification apparatus shown in FIG. 1.

Explanation of symbols

  1 engine, 100 exhaust passage, 110, 120, 160 catalyst housing part, 130, 150 cone part, 140 pipe part, 210, 220, 230 catalyst, 300 injector, 400 side frame, 500 bracket, 510 arm, 520 spacer, 530 Pedestal, 600 urea water.

Claims (4)

An exhaust passage through which exhaust gas from an internal combustion engine mounted on the vehicle flows;
An exhaust purification catalyst provided in the exhaust passage;
An injector for injecting a reducing agent toward the exhaust purification catalyst,
The exhaust passage includes a first portion that houses the exhaust purification catalyst, a second portion that is located upstream of the first portion and that is smaller in width than the first portion, and the second portion. A cone portion provided so as to increase the width of the exhaust passage in a tapered shape toward the first portion;
The first portion, the second portion, and the cone portion are formed so as to be linearly arranged in a direction in which the exhaust gas flows, and the second portion is eccentric with respect to the first portion. Provided in
The injector is attached to the second portion, and injects the reducing agent from the direction in which the second portion is eccentric with respect to the first portion toward the exhaust purification catalyst housed in the first portion. An exhaust purification device for an internal combustion engine.   2. The exhaust gas purification apparatus for an internal combustion engine according to claim 1, wherein the second portion is provided at a position eccentric to the outer side in the vehicle width direction with respect to the first portion.   The exhaust emission control device for an internal combustion engine according to claim 2, further comprising a bracket attached to a side frame provided to extend in the front-rear direction of the vehicle and supporting the second portion.   4. The exhaust gas purification apparatus for an internal combustion engine according to claim 3, wherein the bracket is provided so as to support a portion of the second portion to which the injector is attached from below.

Images