Patent Grant
8137428
The invention relates to an exhaust gas control apparatus for an engine, which purifies exhaust gas.
Japanese Patent Application Publication No. 2001-289028 (JP-A-2001-289028) describes an exhaust gas control apparatus for an engine, which is mounted in a diesel engine and which traps particulate matter (PM) in exhaust gas. The exhaust gas control apparatus includes a ceramic filter, a case that houses the filter, and a mat that is wrapped around the filter. With this structure, particulate matter is trapped in a wall of the filter when the exhaust gas is passing through the filter. As a result, the exhaust gas is purified.
In the engine in which the above-described exhaust gas control apparatus is mounted, as the amount of PM accumulated in the filter increases, the pressure of the exhaust gas increases. Accordingly, if a great amount of PM is accumulated in the filter, the filter may be moved with respect to the case in the downstream direction by the pressure of the exhaust gas. When the case and the filter come into contact with each other due to the movement of the filter with respect to the case, chipping or cracking may occur in the filter. Accordingly, the possibility of contact between the case and the filter should be minimized. However, there have not been proposed any technologies for minimizing the possibility of such contact. Not only in the above-described exhaust gas control apparatus but also in any exhaust gas control apparatuses including a purification structural body that is arranged in a housing and that purifies the exhaust gas, the purification structural body may be deformed due to contact between the housing and the purification structural body. Accordingly, the possibility of contact between the housing and the purification structural body should be minimized, as in the above-described exhaust gas control apparatus.
The invention provides an exhaust gas control apparatus for an engine, which suppresses contact between a housing and a purification structural body due to a movement of the purification structural body with respect to the housing.
A first aspect of the invention relates to an exhaust gas control apparatus for an engine. The exhaust gas control apparatus for an engine includes a housing that has an internal space; a purification structural body that is arranged in the housing and that purifies exhaust gas; and a holding member that is arranged, in the compressed state, between the purification structural body and the housing. The purification structural body includes a main body that has an exhaust passage through which the exhaust gas flows and an assisting body that is provided on the outer peripheral face of the main body. The purification structural body is arranged in the housing with the holding member and the assisting body engaged with each other.
In the exhaust gas control apparatus for an engine according to the first aspect of the invention, the movement of the purification structural body with respect to the housing is restricted by engagement of the holding member with the assisting body. It is therefore possible to suppress contact between the housing and the purification structural body due to the movement of the purification structural body with respect to the housing.
A second aspect of the invention relates to an exhaust gas control apparatus for an engine. The exhaust gas control apparatus for an engine includes a housing that has an internal space; a purification structural body that is arranged in the housing and that purifies exhaust gas; and a holding member that is arranged, in the compressed state, between the purification structural body and the housing. The purification structural body includes a main body that has an exhaust passage through which the exhaust gas flows and an assisting body that is provided on the outer peripheral face of the main body. The purification structural body is arranged in the housing such that the holding member and the assisting body are engaged with each other when the purification structural body moves with respect to the housing.
In the exhaust gas control apparatus for an engine, when the purification structural body moves with respect to the housing, a further movement of the purification structural body with respect to the housing is restricted by engagement of the holding member with the assisting body. It is therefore possible to suppress contact between the housing and the purification structural body due to the movement of the purification structural body with respect to the housing.
In the exhaust gas control apparatus according to each aspect of the invention described above, the holding member and the assisting body may be engaged with each other when the downstream-side end face of the assisting body comes into contact with the holding member.
A third aspect of the invention relates to an exhaust gas control apparatus for an engine. The exhaust gas control apparatus for an engine includes a housing that has an internal space; a purification structural body that is arranged in the housing and that purifies exhaust gas; and a holding member that is arranged, in the compressed state, between the housing and the purification structural body. The purification structural body includes a main body that has an exhaust passage through which the exhaust gas flows and an assisting body that is provided on the outer peripheral face of the main body. The movement of the purification structural body is restricted by engagement of the holding member with the assisting body, when a force that moves the purification structural body with respect to the housing in the downstream direction is applied to the purification structural body.
In the exhaust gas control apparatus for an engine according to the third aspect of the invention, the movement of the purification structural body is restricted by engagement of the holding member with the assisting body. It is therefore possible to suppress contact between the housing and the purification structural body due to the movement of the purification structural body with respect to the housing.
A fourth aspect of the invention relates to an exhaust gas control apparatus for an engine. The exhaust gas control apparatus for an engine includes a housing that has an internal space; a purification structural body that is arranged in the housing and that purifies exhaust gas; and a holding member that is arranged, in the compressed state, between the housing and the purification structural body. The purification structural body includes a main body that has an exhaust passage through which the exhaust gas flows and an assisting body that is provided on the outer peripheral face of the main body. The assisting body and the holding member face each other with a clearance left between the downstream-side end face of the assisting body and the holding member.
In the exhaust gas control apparatus for an engine according to the fourth aspect of the invention, when the purification structural body moves with respect to the housing, the holding member and the assisting body are engaged with each other. Accordingly, a further movement of the purification structural body with respect to the housing is restricted. It is therefore possible to suppress contact between the housing and the purification structural body due to the movement of the purification structural body with respect to the housing.
In the exhaust gas control apparatus according to the fourth aspect of the invention, the amount of the clearance left between the assisting body and the holding member may be set such that, when the purification structural body moves with respect to the housing in the downstream direction, the assisting body comes into contact with the holding member before the purification structural body comes into contact with the housing.
In the exhaust gas control apparatus for an engine according to any one of the first to fourth aspects of the invention, the assisting body may be provided at the upstream-side end portion of the purification structural body.
In this exhaust gas control apparatus for an engine, the holding member is less likely to be exposed to the exhaust gas, because the assisting body is provided at the upstream-side end portion of the purification structural body. It is therefore possible to suppress degradation of the holding member.
A fifth aspect of the invention relates to an exhaust gas control apparatus for an engine. The exhaust gas control apparatus for an engine includes a housing that has an internal space; and a purification structural body that is arranged in the housing and that purifies the exhaust gas. The purification structural body includes a main body that has an exhaust passage through which the exhaust gas flows and an assisting body that is provided on the outer peripheral face of the main body. The purification structural body is arranged in the housing with the holding member and the assisting body engaged with each other.
In the exhaust gas control apparatus for an engine according to the fifth aspect of the invention, the movement of the purification structural body with respect to the housing is restricted, because the purification structural body is arranged in the housing with the housing and the assisting body engaged with each other in advance. It is therefore possible to suppress contact between the housing and the purification structural body due to the movement of the purification structural body with respect to the housing.
In the exhaust gas control apparatus according to the fifth aspect of the invention, the housing and the assisting body may be engaged with each other when the downstream-side end face of the assisting body and a portion of the housing come into contact with each other.
The exhaust gas control apparatus for an engine according to the fifth aspect of the invention may further include a holding member that is arranged, in the compressed state, between the housing and the purification structural body.
In the exhaust gas control apparatus according to the fifth aspect of the invention, the assisting body may be provided at the upstream-side end portion of the purification structural body.
In the exhaust gas control apparatus for an engine thus structured, the holding member is less likely to be exposed to the exhaust gas, because the assisting body is provided at the upstream-side end portion of the purification structural body. It is therefore possible to suppress degradation of the holding member.
A sixth aspect of the invention relates to an exhaust gas control apparatus for an engine. The exhaust gas control apparatus for an engine includes a purification structural body that purifies exhaust gas; and a housing that stores the purification structural body. The purification structural body including a main body that has an exhaust passage through which the exhaust gas flows and an assisting body that is provided on the outer peripheral face of the main body is provided with a restricting member that restricts the movement of the purification structural body with respect to the housing in the downstream direction. The purification structural body is arranged in the housing with the restricting member and the assisting body engaged with each other.
In the exhaust gas control apparatus for an engine according to the sixth aspect of the invention, the movement of the purification structural body with respect to the housing is restricted by engagement of the restricting member with the assisting body. It is therefore possible to suppress contact between the housing and the purification structural body due to the movement of the purification structural body with respect to the housing.
In the exhaust gas control apparatus for an engine according to the sixth aspect of the invention, the restricting member and the assisting body may be engaged with each other, when the downstream-side end face of the assisting body and the restricting member come into contact with each other.
In the exhaust gas control apparatus for an engine according to the sixth aspect of the invention, the restricting member may be arranged so as not to block the exhaust passage formed in the main body of the purification structural body.
In the exhaust gas control apparatus for an engine thus structured, an increase in the pressure of the exhaust gas is suppressed. It is therefore possible to restrict the movement of the purification structural body using the restricting member and to suppress an increase in the pressure of the exhaust gas.
In the exhaust gas control apparatus for an engine according to the sixth aspect of the invention, the restricting member may be a retainer. Alternatively, the restricting member may be a portion of the housing.
The exhaust gas control apparatus for an engine according to the sixth aspect of the invention may further include a holding member that is arranged, in the compressed state, between the housing and the purification structural body.
In the exhaust gas control apparatus for an engine according to each aspect of the invention, the holding member may be a mat made of alumina fibers.
In the exhaust gas control apparatus for an engine according to each aspect of the invention, a clearance may be left between the outer peripheral face of the assisting body and the housing.
In the exhaust gas control apparatus for an engine thus structured, it is possible to suppress promotion of an abrasion and deformation of the assisting body due to contact between the housing and the assisting body. In the exhaust gas control apparatus for an engine according to each aspect of the invention, the assisting body may be a flange provided on the main body of the purification structural body.
The outer diameter of the assisting body may be larger than the inner diameter of the holding member.
A seventh aspect of the invention relates to an exhaust gas control apparatus for an engine. The exhaust gas control apparatus for an engine includes a housing that has an internal space; a purification structural body that is arranged in the housing and that purifies exhaust gas; and a holding member that is arranged, in the compressed state, between the housing and the purification structural body. A shock-absorbing member is provided on the downstream-side end face of the purification structural body.
In the exhaust gas control apparatus for an engine according to the seventh aspect of the invention, when the purification structural body moves with respect to the housing, the shock-absorbing member and the housing come into contact with each other. It is therefore possible to suppress contact between the housing and the purification structural body due to the movement of the purification structural body with respect to the housing.
In the exhaust gas control apparatus according to the seventh aspect of the invention, the purification structural body may include a main body that has an exhaust passage through which the exhaust gas flows and an assisting body that is provided on the outer peripheral face of the main body, the downstream-side end face of the assisting body may be the downstream-side end face of the purification structural body, and the shock-absorbing member may be provided to the assisting body.
In the exhaust gas control apparatus for an engine thus structured, the exhaust passage formed in the main body of the purification structural body is not blocked by the shock-absorbing member. It is therefore possible to suppress contact between the housing and the purification structural body using the shock-absorbing member and to suppress an increase in the pressure of the exhaust gas.
An eighth aspect of the invention relates to an exhaust gas control apparatus for an engine. The exhaust gas control apparatus for an engine includes a housing that has an internal space; a purification structural body that is arranged in the housing and that purifies exhaust gas; and a holding member that is arranged, in the compressed state, between the housing and the purification structural body. A shock-absorbing member is provided on the inner peripheral face of the housing, which faces the downstream-side end face of the purification structural body.
In the exhaust gas control apparatus for an engine according to the eighth aspect of the invention, when the purification structural body moves with respect to the housing, the shock-absorbing member and the housing come into contact with each other. It is therefore possible to suppress contact between the housing and the purification structural body due to the movement of the purification structural body with respect to the housing.
In the exhaust gas control apparatus for an engine according to the eighth aspect of the invention, the purification structural body may include a main body that has a passage through which the exhaust gas flows and an assisting body that is provided on an outer peripheral face of the main body, the downstream-side end face of the assisting body may be the downstream-side end face of the purification structural body, and the shock-absorbing member may be provided on the inner peripheral face of the housing, which faces the downstream-side end face of the assisting body.
In the exhaust gas control apparatus for an engine thus structured, the exhaust passage formed in the main body of the purification structural body is not blocked by the shock-absorbing member. It is therefore possible to suppress contact between the housing and the purification structural body and to suppress an increase in the pressure of the exhaust gas.
In the exhaust gas control apparatus for an engine according to each aspect of the invention, the purification structural body may remove a toxic substance in the exhaust gas using a catalyst.
In the exhaust gas control apparatus for an engine according to each aspect of the invention, the purification structural body may trap particulate matter in the exhaust gas.
The foregoing and further objects, features, and advantages of the invention will become apparent from the following description of example embodiments with reference to the accompanying drawings, wherein the same or corresponding portions will be denoted by the same reference numerals and wherein:
Hereafter, a first embodiment of the invention will be described with reference to
First, the structure of an exhaust system of the engine 1 will be schematically described with reference to
The structure of the exhaust gas control apparatus 2 will be schematically described with reference to
The inner structure of the exhaust gas control apparatus 2 will be described with reference to
A heat-proof mat 5, which is made of alumina fibers, is wrapped around the filter 4. The mat 5 is arranged between the filter case 3 and the filter 4 with an outer peripheral face 5C of the mat 5 kept in contact with an inner peripheral face 31D of the first case 31 and with an inner peripheral face 5D of the mat 5 kept in contact with an outer peripheral face of the filter 4 (an outer peripheral face 41C of a filter body 41). Namely, the mat 5 is arranged, in the compressed state, between the filter case 3 and the filter 4. With this structure, a force is applied from the mat 5 to the filter 4 because the mat 5 attempts to return to its original shape before compression. As a result, the position of the filter 4 with respect to the filter case 3 is maintained. The mat 5 has the function of providing sealing between the filter case 3 and the filter 4 in addition to the above-described function of maintaining the position of the filter 4.
An annular retainer 6 (a restriction element) that restricts the movement of the filter 4 with respect to the filter case 3 and the mat 5 in the downstream direction is provided at a position downstream of the filter 4. The retainer 6 is fitted to the inner peripheral face 31D of the first case 31. The retainer 6 is arranged so as to be in contact with the filter 4.
The structure of the filter 4 will be described with reference to
Multiple plugs 44C are provided, in the hound's tooth check pattern, at upstream-side openings (exhaust gas inlets 44A) of the grid body 42. Namely, the plugs 44C are arranged such that the exhaust gas inlets 44A of the cells 44 are alternately closed. In addition, other plugs 44C are provided, in the hound's tooth check pattern, at downstream-side openings (exhaust gas outlets 44B) of the grid body 42. Namely, the plugs 44C are arranged such that the exhaust gas outlets 44B of the cells 33 are alternately closed. In each cell 44, one of the exhaust gas inlet 44A and the exhaust gas outlet 44B is closed by the plug 44C. Thus, the exhaust gas that enters the filter 4 reliably passes through the partition walls 43 of the grid body 42. As a result, the filter 4 traps the PM with a higher degree of efficiency.
When the exhaust gas is passing through the partition walls 43, the PM in the exhaust gas is trapped in the partition walls 43. NOx in the exhaust gas is absorbed in the NOx catalyst when the air-fuel ratio of the exhaust gas is lean. The absorbed NOx is reduced to hydrocarbon (HC) and carbon monoxide (CO) when the air-fuel ratio of the exhaust gas is rich. The PM trapped in the partition walls 43 is oxidized by active oxygen that is produced when the NOx is absorbed. The PM trapped in the partition walls 43 may be oxidized by increasing the temperature of the filter 4.
The structure of the first flange 45 will be described with reference to
In the exhaust gas control apparatus 2, the filter 4 is arranged in the filter case 3 with a downstream-side end face 45B of the first flange 45 kept in contact with an upstream-side end face 5A of the mat 5. In other words, the filter 4 is arranged in the filter case 3 with the first flange 45 engaged with the mat 5. A clearance is left between the outer peripheral face 45C of the first flange 45 and the inner peripheral face 31D of the first case 31.
The structure of the second flange 46 will be described with reference to
In the exhaust gas control apparatus 2, the filter 4 is arranged in the filter case 3 with the second flange 46 engaged with the retainer 6, namely, with the downstream-side end face 46B of the second flange 46 kept in contact with an upstream-side end face 6A of the retainer 6. In other words, the filter 4 is arranged in the filter case 3 with the second flange 46 engaged with the retainer 6. The mat 5 is wrapped around the filter 4 with an upstream-side end face 46A of the second flange 46 kept in contact with a downstream-side end face 5B of the mat 5. A clearance is left between the outer peripheral face 46C of the second flange 46 and the inner peripheral face 31D of the first case 31. The upstream-side end face 6A of the retainer 6 is in contact with the downstream-side end face 46B of the second flange 46 but is not in contact with the filter body 41 (a portion of the filter 4, in which the cells 44 are formed).
As described above in detail, the exhaust gas control apparatus 2 for an engine according to the first embodiment of the invention produces the following effects.
(1) In the exhaust gas control apparatus 2 according to the first embodiment of the invention, the filter 4 is arranged in the filter case 3 with the second flange 46 of the filter 4 engaged with the retainer 6. With this structure, the movement of the filter 4 with respect to the filter case 3 and the mat 5 in the downstream direction is restricted. As a result, it is possible to suppress contact between the filter case 3 and the filter 4.
(2) In an exhaust gas control apparatus according to related art (for example, an exhaust gas control apparatus described in JP-A-2001-289028), the filter is maintained at a predetermined position only by an elastic force of a mat. Accordingly, if the pressure of the exhaust gas is excessively increased by, for example, accumulation of a great amount of PM in a filter, the filter moves with respect to a filter case. In contrast, the exhaust gas control apparatus 2 according to the first embodiment of the invention has the structure in which the filter 4 is supported from the downstream side by the retainer 6 and the retainer is fitted to the filter case 3. Accordingly, even if the pressure of the exhaust gas is excessively increased as described above, it is possible to appropriately suppress the movement of the filter 4 with respect to the filter case 3 and the mat 5.
(3) In the exhaust gas control apparatus 2 according to the first embodiment of the invention, the filter 4 is arranged in the filter case 3 with the upstream-side end face 6A of the retainer 6 kept in contact with the downstream-side end face 46B of the second flange 46. Accordingly, the following effects are produced. The effects will be described based on the comparison between the exhaust gas control apparatus 2 according to the first embodiment of the invention and a virtual exhaust gas control apparatus 9, shown in
In the exhaust gas control apparatus 9, although the movement of a filter 92 with respect to a filter case 91 is restricted by the retainer 93, the retainer 93 blocks some of exhaust gas outlets 95 of cells 94, which increases the pressure of the exhaust gas. In order to effectively restrict the movement of the filter 92 using the retainer 93 while suppressing an increase in the pressure of the exhaust gas, the area at which the retainer 93 contacts the filter 92 may be decreased to minimize the area in which the exhaust gas outlets 95 are blocked by the retainer 93, as shown in
In contrast to the virtual exhaust gas control apparatus 9, in the exhaust gas control apparatus 2 according to the first embodiment of the invention, the second flange 46 is engaged with the retainer 6 but the filter body 41 is not in contact with the retainer 6. As a result, the retainer 6 does not block the exhaust gas outlets 44B of the cells 44. With this structure, it is possible to suppress an increase in the pressure of the exhaust gas due to blockage of the cells 44 caused by the retainer 6. As a result, the fuel efficiency of the engine 1 improves. Also, a sufficient area at which the second flange 46 is in contact with the retainer 6 is obtained by making the second flange 46 in contact with the retainer 6. With this structure, it is possible to suppress occurrence of chipping and cracking in the filter 4. The outer diameter of the filter body 41 may be substantially equal to that in the related art. Therefore, it is possible to suppress a cost increase due to increases in the sizes of the exhaust gas control apparatus 2 and the mat 5.
(4) In the exhaust gas control apparatus 2 according to the first embodiment of the invention, the filter 4 is arranged with the downstream-side end face 45B of the first flange 45 kept in contact with the upstream-side end face 5A of the mat 5. Thus, the movement of the filter 4 with respect to the filter case 3 and the mat 5 is restricted by the first flange 45 in addition to the retainer 6. As a result, it is possible to more appropriately suppress contact between the filter case 3 and the filter 4.
(5) The first flange 45 is engaged with the mat 5. Accordingly, even if the pressure of the exhaust gas is excessively increased as described above in (2), it is possible to more reliably restrict the movement of the filter 4 with respect to the filter case 3 and the mat 5.
(6) In addition, because the first flange 45 is engaged with the mat 5, the pressure applied to the second flange 46 is decreased. As a result, it is possible to suppress occurrence of chipping and cracking in the second flange 46 due to contact between the second flange 46 and the retainer 6.
(7) Because the first flange 45 is arranged at a position upstream of the upstream-side end face 5A of the mat 5, the upstream-side end face 5A is less likely to be exposed to the exhaust gas. As a result, it is possible to suppress degradation of the mat 5. In the exhaust gas control apparatus 2, if the upstream-side end face 5A is exposed to the exhaust gas, the fibers forming the mat 5 may come out of the upstream-side end face 5A and be carried away with the exhaust gas.
(8) In the exhaust gas control apparatus 2 according to the first embodiment of the invention, the flange outer diameter R1 is set such that a clearance is left between the outer peripheral face 45C of the first flange 45 and the inner peripheral face 31D of the first case 31. Thus, it is possible to suppress occurrence of chipping and cracking in the first flange 45 due to contact between the first case 31 and the first flange 45.
(9) In the exhaust gas control apparatus 2 according to the first embodiment of the invention, the flange outer diameter R2 is set such that a clearance is left between the outer peripheral face 46C of the second flange 46 and the inner peripheral face 31D of the first case 31. Thus, it is possible to suppress occurrence of chipping and cracking in the second flange 46 due to contact between the first case 31 and the second flange 46.
A second embodiment of the invention will be described with reference to
As described above in detail, the exhaust gas control apparatus 2 for an engine according to the second embodiment of the invention produces the effects (1) to (3) and (9) described in the first embodiment of the invention.
A third embodiment of the invention will be described with reference to
As described above in detail, the exhaust gas control apparatus 2 according to the third embodiment of the invention produces the following effects in addition to the effects (4) to (8) described in the first embodiment.
(10) In the exhaust gas control apparatus 2 according to the third embodiment of the invention, the exhaust gas outlets 44B of the cells 44 are not blocked by the retainer 6. Accordingly, it is possible to suppress an increase in the pressure of the exhaust gas due to blockage of the cells 44. In addition, it is possible to improve the fuel efficiency of the engine 1.
(11) Also, the outer diameter of the filter body 41 may be substantially equal to that in the related art. Accordingly, it is possible to suppress a cost increase due to increases in the sizes of the exhaust gas control apparatus 2 and the mat 5.
A fourth embodiment of the invention will be described with reference to
The structure of the fourth case 34 and the third flange 47 will be described with reference to
The third flange 47 is formed as an element (an assisting body) that is engaged with the fourth case 34 to restrict the movement of the filter 4 with respect to the filter case 3 and the mat 5 in the downstream direction. More specifically, the third flange 47 is provided on the outer peripheral face 41C, at the upstream-side end of the filter body 41. The third flange 47 is formed integrally with the filter body 41, and projects in the radial direction AR. The third flange 47 is formed such that an upstream-side end face 47A of the third flange 47 and the upstream-side end face 41A of the filter body 41 are in substantially the same plane. In addition, the third flange 47 is formed so as to be coaxial with the filter body 41. Further, the third flange 47 is formed such that an outer peripheral face 47C of the third flange 47 is positioned further outward than an inner peripheral face 34D of the small-diameter portion 34A (the outer peripheral face 5C of the mat 5) in the radial direction AR. Namely, the flange outer diameter R3 is larger than each of the inner diameter of the small-diameter portion 34A (the case inner diameter RC) and the outer diameter of the mat 5 (a mat outer diameter RD). The flange outer diameter R3 is smaller than the inner diameter of the large-diameter portion 34B (a large-diameter portion inner diameter RE). In the exhaust gas control apparatus 2, the case inner diameter RC and the mat outer diameter RD are substantially equal to each other.
In the exhaust gas control apparatus 2, the filter 4 is arranged in the filter case 3 with the third flange 47 engaged with the fourth case 34, namely, with a downstream-side end face 47B of the third flange 47 kept in contact with a downstream-side end face 34C of the large-diameter portion 34B. In other words, the filter 4 is arranged in the filter case 3 with the third flange 47 engaged with the fourth case 34. A clearance is left between the downstream-side end face 47B of the third flange 47 and the upstream-side end face 5A of the mat 5. In addition, a clearance is left between the outer peripheral face 47C of the third flange 47 and the inner peripheral face 34D of the large-diameter portion 34B. In the fourth embodiment of the invention, the structure in which a clearance is left between the downstream-side end face 47B of the third flange 47 and the upstream-side end face 5A of the mat 5 is employed. Instead of this structure, the structure in which the downstream-side end face 47B is in contact with the upstream-side end face 5A may be employed.
As described above in detail, the exhaust gas control apparatus 2 for an engine according to the fourth embodiment of the invention produces the effects (1) to (7) described in the first embodiment of the invention.
A fifth embodiment of the invention will be described with reference to
The structure of the fifth case 35 and the fourth flange 48 will be described with reference to
The fourth flange 48 is formed as an element (an assisting body) that is engaged with the fifth case 35 to restrict the movement of the filter 4 with respect to the filter case 3 and the mat 5 in the downstream direction. More specifically, the fourth flange 48 is provided on the outer peripheral face 41C of the filter body 41, at the downstream-side end of the filter body 41. Also, the fourth flange 48 is formed integrally with the filter body 41, and projects from the outer peripheral face 41C in the radial direction AR. The fourth flange 48 is formed such that a downstream-side end face 48B of the fourth flange 48 and the downstream-side end face 41B of the filter body 41 are in substantially the same plane. The fourth flange 48 is formed so as to be coaxial with the filter body 41. Also, the fourth flange 48 is formed such that an outer peripheral face 48C of the fourth flange 48 is positioned further outward than an inner peripheral face 35D of the small-diameter portion 35A (the outer peripheral face 5C of the mat 5) in the radial direction AR. Namely, the flange outer diameter R4 is larger than each of the case inner diameter RC and the mat outer diameter RD. Also, the flange outer diameter R4 is smaller than the inner diameter of the large-diameter portion 35B (the large-diameter portion inner diameter RE).
In the exhaust gas control apparatus 2, the filter 4 is arranged in the filter case 3 with the fourth flange 48 engaged with the fifth case 35, namely, with the downstream-side end face 48B of the fourth flange 48 kept in contact with a downstream-side end face 35C of the large-diameter portion 35B. In other words, the filter 4 is arranged in the filter case 3 with the fourth flange 48 engaged with the fifth case 35. A clearance is left between an upstream-side end face 48A of the fourth flange 48 and the downstream-side end face 5B of the mat 5. Also, a clearance is left between the outer peripheral face 48C of the fourth flange 48 and the inner peripheral face 35D of the large-diameter portion 35B. The downstream-side end face 35C of the large-diameter portion 35B is in contact with the downstream-side end face 48B of the fourth flange 48 but is not in contact with the filter body 41 (the portion of the filter 4, in which the cells 44 are formed). In the fifth embodiment of the invention, the structure in which a clearance is left between the upstream-side end face 48A of the fourth flange 48 and the downstream-side end face 5B of the mat 5 is employed. Instead of this structure, the structure in which the upstream-side end face 48A is in contact with the downstream-side end face 5B may be employed.
As described above in detail, the exhaust gas control apparatus 2 for an engine according to the fifth embodiment of the invention produces the above-described effects (1) to (9) in the first embodiment of the invention.
A sixth embodiment of the invention will be described with reference to
As shown in
As described above in detail, the exhaust gas control apparatus 2 for an engine according to the sixth embodiment of the invention produces the following effects.
(1) In the exhaust gas control apparatus 2 according to the sixth embodiment of the invention, the filter 4 is arranged in the filter case 3 such that the downstream-side end face 45B of the first flange 45 faces the upstream-side end face 5A of the mat 5 with a clearance left therebetween. With this structure, when the filter 4 moves with respect to the filter case 3 and the mat 5, the movement of the filter 4 is restricted by engagement of the first flange 45 with the mat 5. Accordingly, it is possible to suppress contact between the filter case 3 and the filter 4, which is caused by the movement of the filter 4.
(2) Also, it is possible to suppress occurrence of chipping and cracking in the filter 4, which is caused by contact between the filter 4 and the filter case 3. (3) In addition, because the first flange 45 is arranged at a position upstream of the upstream-side end face 5A of the mat 5, the upstream-side end face 5A is less likely to be exposed to the exhaust gas. As a result, it is possible to suppress degradation of the mat 5.
(4) In the exhaust gas control apparatus 2 according to the sixth embodiment of the invention, the flange outer diameter R1 is set such that a clearance is left between the outer peripheral face 45C of the first flange 45 and the inner peripheral face 31D of the first case 31. Thus, it is possible to suppress occurrence of chipping and cracking in the first flange 45, which is caused by contact between the first case 31 and the first flange 45.
A seventh embodiment of the invention will be described with reference to
As shown in
As described above in detail, the exhaust gas control apparatus 2 for an engine according to the seventh embodiment of the invention produces the following effects.
(1) In the exhaust gas control apparatus 2 according to the seventh embodiment of the invention, the shock-absorbing member 36 is provided on the inner peripheral face 33D of the third case 33 that faces the downstream-side end face 46B of the second flange 46. Accordingly, it is possible to suppress contact between the filter case 3 and the filter 4, which is caused by the movement of the filter 4.
(2) In addition, when the filter 4 comes into contact with the shock-absorbing member 36, the cells 44 are not blocked by the shock-absorbing member 36. Accordingly, it is possible to suppress an increase in the pressure of the exhaust gas. Also, it is possible to suppress reduction in the fuel efficiency of the engine 1.
An eighth embodiment of the invention will be described with reference to
As shown in
As described above in detail, the exhaust gas control apparatus 2 according to the eighth embodiment of the invention produces the following effects.
(1) In the exhaust gas control apparatus 2 according to the eighth embodiment of the invention, the shock-absorbing member 36 is provided on the downstream-side end face 46B of the second flange 46. Accordingly, it is possible to suppress contact between the filter case 3 and the filter 4, which is caused by the movement of the filter 4.
(2) Because the second flange 46 is formed on the filter 4, the shock-absorbing member 36 is provided to the filter 4 without blocking the cells 44. Accordingly, it is possible to suppress an increase in the pressure of the exhaust gas. In addition, it is possible to suppress reduction in the fuel efficiency of the engine 1.
Each of the embodiments described above may be modified as follows. In each embodiment described above, the filter 4 is formed such that the upstream-side end face 41A of the filter body 41 and the upstream-side end face 45A of the first flange 45 (or the upstream-side end face 47A of the third flange 47) are in substantially the same plane. Alternatively, a level difference may be made between the upstream-side end face 41A and the upstream-side end face 45A (or the upstream-side end face 47A), as shown in
In each embodiment described above, the filter 4 is formed such that the downstream-side end face 41B of the filter body 41 and the downstream-side end face 46B of the second flange 46 (or the downstream-side end face 48B of the fourth flange 48) are in substantially the same plane. Alternatively, a level difference may be made between the downstream-side end face 41B and the downstream-side end face 46B (or the downstream-side end face 48B), as shown in
In each embodiment described above, the first flange 45 (or the third flange 47) is provided at a position upstream of the filter body 41, as an assisting body that is engaged with the mat 5 (or the filter case 3) to restrict the movement of the filter 4. However, such assisting body provided at a position upstream of the filter body 41 is not limited to a flange. For example, as shown in
In each embodiment described above, the second flange 46 (or the fourth flange 48) is provided at a position downstream of the filter body 41, as an assisting body that is engaged with the retainer 6 (or the filter case 3) to restrict the movement of the filter 4. However, such assisting body provided at a position downstream of the filter body 41 is not limited to a flange. For example, as shown in
The embodiments described above may be combined with each other as needed. In each embodiment described above, the mat 5 formed of alumina fibers is employed. However, the material of the mat 5 may be changed as needed.
Each embodiment of the invention described above is applied to the exhaust gas control apparatus 2 in which the NOx catalyst is supported by the filter 4. Alternatively, each embodiment of the invention described above may be applied to an exhaust gas control apparatus in which a NOx catalyst is not provided.
Each embodiment of the invention described above is applied to the exhaust gas control apparatus 2 that purifies the exhaust gas by trapping PM. Alternatively, each embodiment of the invention may be applied to an exhaust gas control apparatus in which PM is not trapped, namely, the exhaust gas is purified using only a catalyst.
Each embodiment of the invention described above is applied to the exhaust gas control apparatus 2 for a diesel engine. Alternatively, each embodiment of the invention may be applied to an exhaust gas control apparatus for another type of engine. In other words, each embodiment of the invention may be applied to any types of exhaust gas control apparatuses in which a toxic substance in the exhaust gas is removed so as not to be discharged to the outside using a purification structural body stored in a case.
While the invention has been described with reference to what are considered to be example embodiments thereof, it is to be understood that the invention is not limited to the described embodiments or constructions. On the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the described invention are shown in various combinations and configurations, which are example, other combinations and configurations, including more, less or only a single element, are also within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-177079 | Jun 2006 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2007/001747 | 6/26/2007 | WO | 00 | 12/8/2008 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2008/001197 | 1/3/2008 | WO | A |
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