JP2017044074A - Thermal insulation member - Google Patents

Abstract

In a heat insulating member provided between an exhaust pipe and an accommodating member that accommodates an injection valve that injects an additive into an exhaust pipe of an internal combustion engine and is attached to the exhaust pipe, the heat is transmitted from the exhaust pipe to the accommodating member and the injection valve. Provided is a heat insulating member capable of further suppressing heat.
A heat insulating member is provided with a low heat conductive member, such as ceramics, having a lower thermal conductivity than an adapter as a housing member, and a part of the low heat conductive member is in contact with the outside air. And a high thermal conductive member 32 such as copper or aluminum having a higher thermal conductivity than the member 31. The high heat conductive member 32 is provided so as to penetrate the surface of the low heat conductive member 31 in the short direction of the low heat conductive member 31. Both end portions of the high heat conductive member 32 are in contact with the outside air. Sealing members 33 are provided on both surfaces 311 and 312 of the low heat conducting member 31 to prevent the exhaust gas from leaking to the outside. The seal member 33 is partially formed with a convex portion, and the convex portion is in contact with the exhaust pipe, the adapter, and the low heat conducting member 31.
[Selection] Figure 3

Description

  The present invention provides an injection valve for injecting an additive into an exhaust pipe of an internal combustion engine and is provided between a storage member attached to the exhaust pipe and the exhaust pipe, and heat from the exhaust pipe is applied to the storage member and the injection valve. The present invention relates to a heat insulating member that suppresses transmission.

  Conventionally, a urea SCR system (SCR: Selective Catalytic Reduction) is known as one of systems for purifying exhaust gas discharged from an internal combustion engine (see, for example, Patent Document 1). In this urea SCR system, a catalyst part for reducing and purifying NOx in exhaust gas is provided in an exhaust pipe of an internal combustion engine, and urea water (reductant) as an additive is provided upstream of the catalyst part. Is provided.

  Here, the exhaust gas is hot, and the nozzle tip of the injection valve in which the nozzle holes are formed is exposed to the high temperature exhaust gas. When the nozzle tip reaches a high temperature, foreign matter (PM (particulate matter), unburned fuel, lubricating oil, additive, or a substance produced by a chemical reaction thereof) contained in the exhaust gas is contained in the nozzle tip. It becomes easy to adhere as a deposit, and there is a risk of causing problems such as the clogging of the nozzle hole.

  In Patent Document 1, in order to protect the addition valve from being heated by the high-temperature exhaust gas, the addition valve is accommodated in a housing member (heat radiating member), and the heat of the addition valve is radiated to the outside through the housing member. Yes. The housing member of Patent Document 1 is attached to the exhaust pipe via a heat insulating gasket as a heat insulating member.

JP 2013-238167 A

  Since most of the heat transmitted to the injection valve is transmitted from the wall surface of the exhaust pipe, it is necessary to reduce the heat transfer amount from the exhaust pipe to the housing member and the injection valve as much as possible.

  Then, this invention makes it a subject to provide the heat insulation member which can suppress more the heat transfer from an exhaust pipe to a storage member or an injection valve in the heat insulation member provided between an exhaust pipe and a storage member.

In order to solve the above-mentioned problem, the heat insulating member of the present invention is provided between a housing member that houses an injection valve that injects an additive into an exhaust pipe of an internal combustion engine and is attached to the exhaust pipe, and the exhaust pipe.
A low thermal conductive member having a lower thermal conductivity than the housing member;
A part of the low thermal conductive member is provided so as to be in contact with the outside air, and a high thermal conductive member having a higher thermal conductivity than the low thermal conductive member,
It is characterized by providing.

  Conventional heat insulating members such as Patent Document 1 are composed of only a low heat conductive member having a low thermal conductivity, whereas the heat insulating member of the present invention is a high heat conductive member having a high thermal conductivity in the low heat conductive member. I have. This high heat conductive member has higher thermal conductivity than the low heat conductive member, and further, a part of the high heat conductive member is provided so as to be in contact with the outside air, so that the heat transmitted to the low heat conductive member can be dissipated through the high heat conductive member. it can. Thus, a heat dissipation function can be provided to a heat insulation member by providing a high heat conductive member. Thereby, it can suppress more that heat is transmitted from an exhaust pipe to an accommodation member or an injection valve via a heat insulation member.

It is sectional drawing which showed the state in which the adapter and the heat insulation member which accommodated the injection valve were attached to the exhaust pipe. It is a top view of a heat insulation member. It is sectional drawing when a heat insulation member is cut by the III-III line of FIG. It is an enlarged view of the A section of FIG. It is sectional drawing which showed the state in which the adapter and the heat insulation member which accommodated the injection valve were attached to the exhaust pipe, and was the figure which showed the movement of heat from exhaust gas to an exhaust pipe, a heat insulation member, and an adapter. It is sectional drawing when a heat insulation member is cut | disconnected by the VI-VI line of FIG. 5, and is the figure which showed the heat transfer from a low heat conductive member to a high heat conductive member, and the heat transfer from a high heat conductive member to external air. It is the figure which compared the amount of heat transfer to an adapter between the structure with a high heat conductive member and a convex part, and the structure without a high heat conductive member and a convex part. It is the figure which compared the amount of heat transfer to an adapter between the structure with a high heat conductive member and a convex part, and the structure without a high heat conductive member and a convex part. It is a figure corresponding to the A section of Drawing 1 at the time of using a heat insulation member which does not have a convex part. 10 is a plan view of a heat insulating member according to Modification 1. FIG. 10 is a plan view of a heat insulating member according to Modification 2. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the injection valve 2 is attached to an exhaust pipe 4 of an internal combustion engine such as a diesel engine mounted on a vehicle via an adapter 1 described later. The exhaust pipe 4 is disposed at a position exposed to the outside air under the vehicle floor. The injection valve 2 is formed in a shape that is long in one direction, and has a cylindrical nozzle body 21 on the distal end side in the longitudinal direction, and the distal end 22 of the nozzle body 21 is provided so as to be exposed in the exhaust pipe 4. It is done. The injection valve 2 injects urea water as an additive into the exhaust pipe 4 from an injection hole formed at the tip 22. The injection valve 2 is installed such that the axis L1 of the injection valve 2 is at right angles to the exhaust pipe 4, for example, but may be installed inclined toward the SCR catalyst (downstream side).

  An SCR catalyst that selectively reduces and purifies NOx in the exhaust gas is installed in the exhaust pipe 4 downstream of the injection valve 2. The urea water added from the injection valve 2 is hydrolyzed by the exhaust heat, thereby generating ammonia (NH3). The reduction reaction of ammonia and NOx is performed in the SCR catalyst, so that NOx is decomposed (purified) into water and nitrogen. Thus, the injection valve 2 constitutes a part of the urea SCR system.

  The injection valve 2 is accommodated in an adapter 1 as an accommodating member, and the adapter 1 is attached to the exhaust pipe 4. The adapter 1 is disposed outside the exhaust pipe 4 and has a main body portion 11 and a plurality of (in this embodiment) formed so as to protrude sideways from the lower portion of the main body portion 11 (the end portion on the exhaust pipe 4 side). The two flange portions 12 and the lower central portion of the main body portion 11 protrude in the axial direction of the adapter 1 (in the insertion direction of the injection valve 2 into the adapter 1 and in the axial direction of the accommodating space 13 described later). And a tip projecting portion 18 formed on the head.

  The main body 11 and the tip protrusion 18 are formed in a coaxial cylindrical shape. That is, a through hole 13 is formed in the main body 11 and the tip protrusion 18 so as to penetrate from the upper end of the main body 11 to the lower end (tip) of the tip protrusion 18. The through hole 13 is an accommodation space for accommodating the injection valve 2. In the accommodation space 13, a part from the tip 22 of the injection valve 2, specifically, the whole nozzle body 21 and a part of the upstream portion 23 from the nozzle body 21 are accommodated. A portion of the accommodation space 13 where the nozzle body 21 is disposed is formed to have the same diameter as the nozzle body 21. That is, the outer peripheral surface of the nozzle body 21 is in contact with the wall surface of the accommodation space 13. In addition, another member (for example, a member having high thermal conductivity) is interposed between the wall surface of the accommodating space 13 and the outer peripheral surface of the nozzle body 21, and the outer peripheral surface of the nozzle body 21 and the accommodating space 13 are interposed via the member. You may make a wall surface contact. Further, in the present embodiment, the tip 22 is disposed above the tip position of the tip protrusion 18 (on the main body 11 side), but may be disposed at a position that coincides with the tip of the tip protrusion 18. .

  A part from the upstream end of the injection valve 2 is accommodated in the cover member 52. The cover member 52 is attached to the upper end of the main body 11. The cover member 52 restricts the injection valve 2 from moving in the axial direction.

  The flange portions 12 are formed at two locations, and each flange portion 12 projects to the side in the opposite direction with the main body portion 11 interposed therebetween. Bolt holes 15 are formed in each flange portion 12. The exhaust pipe 4 is formed with an attachment portion 41 for attaching the adapter 1. The mounting portion 41 has a flat mounting surface 42 (outer surface). A bolt hole 44 is formed in the attachment portion 41. By inserting the bolts 51 into the bolt holes 15 and 44, the adapter 1 is attached to the attachment portion 41 (exhaust pipe 4) via the heat insulating member 3 described later.

  Moreover, the main-body part 11 and each flange part 12 have the end surface 16 which forms the same plane. The end surface 16 becomes a contact surface that comes into contact with the mounting surface 42 via the heat insulating member 3. The end surface 16 is arranged in a positional relationship (parallel positional relationship) facing the mounting surface 42 of the exhaust pipe 4. In addition, a concave portion 17 is partially formed on the end surface 16 in order to suppress a contact area with the heat insulating member 3 (exhaust pipe 4). The concave portion 17 is formed, for example, at a position between the tip protruding portion 18 and the bolt hole 15.

  In addition to the bolt hole 44, a through hole 43 that penetrates between the attachment surface 42 and the inner wall surface of the exhaust pipe 4 is formed in the attachment portion 41. The through hole 43 is formed to have a diameter larger than that of the tip protruding portion 18, and the tip protruding portion 18 is partially disposed in the through hole 43 on the tip side. As a result, the tip 22 of the injection valve 2 is exposed in the exhaust pipe 4.

  Inside the adapter 1 (main body part 11), a pipe line 14 is formed through which a coolant for cooling the injection valve 2 circulates. In this pipe line 14, cooling water of the internal combustion engine flows as a coolant. The pipe line 14 is formed so as to surround the nozzle body 21 at the height position of the nozzle body 21.

  The adapter 1 has a role of attaching the injection valve 2 to the exhaust pipe 4 and a role of cooling the injection valve 2 (a role of radiating heat of the injection valve 2). Therefore, the adapter 1 is formed of a material having high thermal conductivity so as to be efficiently cooled by the coolant circulating in the conduit 14, and specifically, for example, formed of aluminum (for example, aluminum die casting such as ADC12). . The thermal conductivity of the adapter 1 is, for example, 100 W / m · K or more.

  A cylindrical plate member 6 is provided so as to surround the periphery of the tip protrusion 18. A flange portion 62 is formed at the base of the plate member 6 so as to protrude radially outward. The plate member 6 is fixed by sandwiching the flange portion 62 between the adapter 1 and the heat insulating member 3. An opening 61 is formed at the tip of the plate member 6, and the tip 22 of the injection valve 2 is exposed from the opening 61. A gap is formed between the inner peripheral surface of the plate member 6 and the outer peripheral surface of the tip protrusion 18. This gap suppresses the transfer of high-temperature heat to the tip protrusion 18 and the nozzle body 2. The material of the plate member 6 can be made of stainless steel, for example. Thereby, the corrosion resistance with respect to the injected urea water and the heat resistance with respect to high temperature exhaust gas can be provided.

  Between the adapter 1 and the exhaust pipe 4 (attachment part 41), the heat insulation member 3 for suppressing heat transfer from the exhaust pipe 4 to the adapter 1 and the injection valve 2 is disposed. The heat insulating member 3 is formed in a plate shape, and when viewed in a plan view of FIG. 2, the cross-sectional shape of the adapter 1 at a position where the flange portion 12 of the adapter 1 is formed (perpendicular to the axial direction of the accommodation space 13). The cross-sectional shape of the adapter 1 when it is cut by a plane to be cut) is formed. That is, the heat insulating member 3 includes a central portion 3a formed in the same planar view shape as the main body portion 11 of the adapter 1 and a flange portion of the adapter 1 that is located on the opposite side of the central portion 3a. 12 and two side parts 3b formed in a plan view shape similar to FIG.

  The central portion 3 a is disposed at a position facing the main body portion 11. A through hole 341 having a circular shape in plan view is formed in the central portion 3a so as to penetrate in the thickness direction of the heat insulating member 3 (a direction perpendicular to the paper surface of FIG. 2; the vertical direction of FIG. 3). In the through hole 341, the tip protrusion 18, a part from the tip 22 of the injection valve 2, and the plate member 6 are arranged.

  A through hole 342 having an elliptical shape in plan view that penetrates in the thickness direction of the heat insulating member 3 is formed in the side portion 3b. The side portion 3 b is disposed at a position facing the flange portion 12 so that the through hole 342 coincides with the bolt hole 15 of the flange portion 12 and the bolt hole 44 of the exhaust pipe 4. And the bolt 51 for fixing the adapter 1 to the exhaust pipe 4 is also inserted into the through hole 342, so that the heat insulating member 3 is fixed between the exhaust pipe 4 (mounting portion 41) and the adapter 1. .

  As shown in FIG. 3, the heat insulating member 3 includes a low heat conductive member 31, a high heat conductive member 32, and a seal member 33. The low heat conductive member 31 is a member constituting most of the heat insulating member 3, and is formed in a shape equivalent to the overall shape of the heat insulating member 3. That is, the low heat conductive member 31 is formed in a plate shape and a shape having a central portion 3a and two side portions 3b (see FIG. 2). Further, the outer shape (outer shape shown in FIG. 6) of the low thermal conductive member 31 in plan view has the same shape as the outer shape (outer shape shown in FIG. 2) of the heat insulating member 3 as a whole. Further, the outer shape of the low heat conducting member 31 in the sectional view shown in FIG. 3 is also substantially the same shape as the outer shape in the sectional view of the entire heat insulating member 3 (strictly, the same shape as the outer shape of the heat insulating member 3 excluding the seal member 33). Have Moreover, both the plate | board surface which faced the end surface 16 side of the adapter 1 and the plate | board surface which faced the attachment surface 42 side of the exhaust pipe 4 of the low heat conductive member 31 are formed in the plane.

  The low heat conductive member 31 is formed of a material (heat insulating material) having a lower thermal conductivity than the adapter 1 and the exhaust pipe 4 (for example, stainless steel). Specifically, the low thermal conductive member 31 is made of ceramics, for example. The thermal conductivity of the low thermal conductive member 31 is preferably as low as possible, preferably 10 W / m · K or less, more preferably 1 W / m · K or less.

  The high heat conductive member 32 is formed of a material (for example, copper or aluminum) having a higher thermal conductivity than the low heat conductive member 31. The thermal conductivity of the high thermal conductive member 32 may be equal to the thermal conductivity of the adapter 1, may be lower than the thermal conductivity of the adapter 1, or may be higher than the thermal conductivity of the adapter 1.

  The high heat conductive member 32 is provided in the low heat conductive member 31 in such a manner that a part thereof is exposed from the low heat conductive member 31. Specifically, the high heat conductive member 32 is formed in a thin plate shape that is thinner than the plate thickness of the low heat conductive member 31. The high heat conductive member 32 has a low heat so that one plate surface of the high heat conductive member 32 forms the same plane as the surfaces 311 and 312 (surfaces facing the adapter 1 side and the exhaust pipe 4 side) of the low heat conductive member 31. Provided in the conductive member 31. That is, grooves 313 (see FIG. 4) having the same thickness and the same shape as the plate thickness of the high heat conductive member 32 are formed on the surfaces 311 and 312 of the low heat conductive member 31 and are press-fitted into the grooves 313. A high heat conducting member 32 is provided. Further, as shown in FIG. 3, the plate thickness direction of the high heat conduction member 32 is the plate thickness direction of the low heat conduction member 31, in other words, the direction from the attachment surface 42 of the exhaust pipe 4 toward the end surface 16 of the adapter 1 (attachment surface 42. , The normal direction of the end face 16).

  Furthermore, the direction of the line (III-III line in FIG. 2) passing through the center of the both side portions 3b of the low heat conducting member 31 is perpendicular to both the longitudinal direction and the thickness direction (vertical direction in FIG. 3). When the direction is the short direction (vertical direction in FIG. 2), the high heat conductive member 32 is formed in a shape extending in the short direction of the low heat conductive member 31. Specifically, the high heat conductive member 32 has a length penetrating between both ends of the low heat conductive member 31 in the short direction of the low heat conductive member 31. That is, as shown in FIG. 6, the high thermal conductive member 32 has a length that occupies the entire range from one end 314 located in the short direction of the low thermal conductive member 31 to the other end 315. At this time, the short direction (the vertical direction in FIG. 6) of the low heat conductive member 31 is the longitudinal direction of the high heat conductive member 32, and the long direction (the horizontal direction in FIG. 6) of the low heat conductive member 31 is the short direction of the high heat conductive member 32. Then, both end portions 321 in the longitudinal direction of the high heat conducting member 32 are not projected with respect to both end portions 314 and 315 of the low heat conducting member 31, that is, form the same plane as the both end portions 314 and 315.

  Thus, as shown in FIG. 6, one plate surface 322 of the high heat conductive member 32 and both end portions 321 in the longitudinal direction are exposed from the low heat conductive member 31 (not in contact with the low heat conductive member 31), and the other The plate surface and both ends 323 in the short direction are in contact with the low heat conducting member 31.

  As shown in FIG. 3, the high heat conductive members 32 are arranged at four locations in the low heat conductive member 31. Here, the heat insulating member 3 is formed in a symmetric shape with respect to the plane 100 perpendicular to the thickness direction (vertical direction in FIG. 3), and both the plane 100 and the line III-III in FIG. It is formed in a symmetrical shape with respect to the plane 101 perpendicular to the plane. The plane 100 is a plane that passes through the center position in the thickness direction of the low thermal conductive member 31. The plane 101 is a plane that passes through the center of the central through hole 341. Therefore, the four high heat conducting members 32 are formed in the same shape or symmetrical shape with each other, and are disposed at positions symmetrical with respect to the planes 100 and 101. That is, the high heat conductive member 32 is disposed on both surfaces 311 and 312 of the low heat conductive member 31, and is between the central through hole 341 and the right through hole 342, and between the central through hole 341 and the left through hole. 342 between both. At this time, the high heat conductive member 32 disposed on one surface 311 and the high heat conductive member 32 disposed on the other surface 312 are in a positional relationship equidistant to the plane 100. Further, the high heat conductive member 32 disposed on the right side of the central through hole 341 and the high heat conductive member 32 disposed on the left side are in a positional relationship equidistant with respect to the plane 101.

  Further, the two high heat conductive members 32 arranged on the right side of the central through hole 341 are in a positional relationship facing each other with a space therebetween. Similarly, the two high heat conductive members 32 arranged on the left side of the central through hole 341 are in a positional relationship facing each other with a space therebetween. Further, the thickness of the low heat conductive member 31 is larger than the total thickness of the two high heat conductive members 32, and therefore, the low heat conductive member 32 is disposed between the two high heat conductive members 32 opposed in the thickness direction. 31 is interposed.

  Furthermore, each high heat conductive member 32 is disposed at a position where at least a part thereof faces the concave portion 17 (see FIG. 1) of the adapter 1. As a result, the contact area between the end surface 16 of the adapter 1 and the high heat conductive member 32 via the seal member 33 is reduced. Thus, in order to suppress heat transfer from the heat insulating member 3 to the adapter 1, it is preferable that the low heat conductive member 31 is brought into contact with the end surface 16 via the seal member 33.

  The shape (size, thickness) and number of each high heat conductive member 32 can be set as appropriate, but if the proportion of the high heat conductive member 32 in the thickness direction of the heat insulating member 3 is excessively large, the exhaust pipe 4 There is a possibility that the amount of heat transfer from to the adapter 1 increases. Therefore, it is preferable that the total thickness of a plurality (two in the present embodiment) of the high heat conductive members 32 opposed to each other in the thickness direction is, for example, half or less of the thickness of the low heat conductive member 31. Further, when the high heat conductive member 32 is formed in a size that is somewhat wide in a direction perpendicular to the thickness direction (in-plane direction of the paper in FIG. 6), the low heat conductive member 31 to the high heat conductive member 32. Can promote heat transfer to. However, even if the high heat conductive member 32 is too large in the in-plane direction of the paper surface of FIG. 6, the amount of heat transfer from the high heat conductive member 32 to the adapter 1 increases. Therefore, it is preferable that the high heat conductive member 32 has a size as wide as possible in the in-plane direction of the paper surface of FIG. 6 as much as possible in a portion that does not contact the end face 16 of the adapter 1 (specifically, a position facing the concave portion 17).

  The seal member 33 is attached to the low heat conductive member 31 by, for example, rivets on both surfaces 311 and 312 of the low heat conductive member 31. The seal member 33 is formed in a thin plate shape that is thinner than the low heat conductive member 31, for example, and has a plan view similar to the planar view shape (see FIG. 6) of the low heat conductive member 31 when viewed from the plan view of FIG. It is formed in a shape (a shape having a central portion 3a and two side portions 3b). FIG. 2 shows a plan view shape of the seal member 33.

  The seal member 33 is a member that suppresses the exhaust gas flowing through the exhaust pipe 4 from leaking to the outside through the gap between the exhaust pipe 4 and the heat insulating member 3 or the gap between the heat insulating member 3 and the adapter 1. Specifically, the seal member 33 is formed of a material (for example, a metal such as stainless steel) having a smaller surface roughness than the low thermal conductive member 31 and excellent heat resistance. Thus, the leakage of the exhaust gas can be effectively suppressed by interposing the seal member 33 having a small surface roughness between the exhaust pipe 4 and the low heat conductive member 31 and between the low heat conductive member 31 and the adapter 1. .

  As shown in FIG. 4, the surface 331 of the seal member 33 disposed on the surface 311 facing the adapter 1 of the low heat conducting member 31 is in contact with the end face 16 of the adapter 1. The surface 331 of the seal member 33 disposed on the surface 312 of the low heat conducting member 31 facing the exhaust pipe 4 is in contact with the mounting surface 42 of the exhaust pipe 4. At this time, in order to reduce the contact area between the seal member 33, the adapter 1, and the exhaust pipe 4, a convex portion 332 is partially formed on the surface 331 of the seal member 33. The convex portion 332 is formed at a position where the seal member 33 contacts the adapter 1 and the exhaust pipe 4. Specifically, as shown in FIG. 2, the protrusions 332 are formed at three locations around the central through hole 341 and around the two left and right through holes 342. In FIG. 2, the convex portion 332 of the seal member 33 disposed on the upper side is shown, but the convex portion 332 is formed around the three through holes 341 and 342 also in the lower seal member 33.

  As a result, as shown in FIG. 4, the convex portion 332 of the sealing member 33 disposed on the upper side and the end surface 16 of the adapter 1 are in contact with each other, and other than the convex portion 332 is not in contact with the end surface 16. Similarly, the convex portion 332 of the seal member 33 arranged on the lower side and the attachment surface 42 of the exhaust pipe 4 are in contact with each other, and the portions other than the convex portion 332 are not in contact with the attachment surface 42.

  Further, a convex portion 334 is partially formed on the back surface 333 of the seal member 33 which is a surface that contacts the surfaces 311 and 312 of the low thermal conductive member 31. In the present embodiment, the convex portion 334 is formed only at one location around the central through hole 341. The convex portion 334 is preferably formed in the vicinity of the high heat conductive member 32 so that the air layer 35 is formed between the high heat conductive member 32 and the seal member 33. In the present embodiment, the convex portion 334 is formed at a portion of the back surface 333 where the opposed position of the high heat conductive member 32 is removed, but may be formed at the opposed position of the high heat conductive member 32. In this case, the convex portion 334 contacts the high heat conductive member 32.

  In this way, the convex portion 334 is also formed on the back surface 333 of the seal member 33, so that the convex portion 334 comes into contact with the surfaces 311 and 312 of the low heat conductive member 31, and the seal member 33 and the low heat conductive member 31 or high heat An air layer 35 is partially formed between the conductive members 32. In addition, in the position away from the convex part 334, the back surface 333 of the sealing member 33 and the surfaces 311 and 312 of the low heat conductive member 31 are in direct contact.

  Further, as described above, since the heat insulating member 3 is formed symmetrically with respect to the planes 100 and 101 (see FIG. 3), the seal member 33 is formed symmetrically with respect to the planes 100 and 101. That is, the seal member 33 disposed on the upper side and the seal member 33 disposed on the lower side are formed in the same shape, and specifically, convex portions 332 and 334 are formed at symmetrical positions with respect to the plane 100. Yes. In addition, each seal member 33 has convex portions 332 and 334 formed at symmetrical positions with respect to the plane 101.

  In addition, since the sealing member 33 is disposed so as to cover the surfaces 311 and 312 of the low heat conductive member 31, the surface 322 of the high heat conductive member 32 (see FIG. 6; see FIG. 6). The surface exposed to 31) is not exposed to the seal member 33. On the other hand, both end portions 321 (see FIG. 6) of the high heat conductive member 32 are exposed to both the low heat conductive member 31 and the seal member 33. As described above, since the exhaust pipe 4 is disposed at a position exposed to the outside air under the floor of the vehicle, the portion of the heat insulating member 3 that is not in contact with the adapter 1 or the exhaust pipe 4 is in contact with the outside air. That is, both end portions 321 of the high heat conductive member 32 are in contact with the outside air.

  Next, the effect of this embodiment is demonstrated with reference to FIG. 5, FIG. The wavy arrows in FIGS. 5 and 6 indicate heat transfer. High-temperature exhaust gas flows through the exhaust pipe 4, and the exhaust gas contacts the wall surface of the exhaust pipe 4, so that the temperature of the wall surface of the exhaust pipe 4 becomes high. Specifically, for example, the temperature of the attachment portion 41 to which the heat insulating member 3 is attached is about 150 to 300 ° C. (see FIG. 5).

  In this embodiment, the adapter 1 is not directly attached to the high temperature attachment part 41, but the heat insulating member 3 is interposed therebetween. Since most of the heat insulating member 3 is formed of the low heat conducting member 31, heat transfer from the high temperature mounting portion 41 to the adapter 1 can be suppressed. In addition, a high heat conductive member 32 is disposed in the heat insulating member 3 (in the low heat conductive member 31). The high heat conductive member 32 has a higher thermal conductivity than the low heat conductive member 31, and a part 321 is in contact with the outside air. Therefore, the heat of the low heat conductive member 31 can be radiated to the outside air via the high heat conductive member 32 (see FIGS. 5 and 6). That is, the heat transferred from the exhaust pipe 4 to the low heat conductive member 31 is transferred to the high heat conductive member 32 in contact with the outside air. The heat transmitted to the high heat conductive member 32 is radiated from the both ends 321 to the outside air, and the temperature rise of the high heat conductive member 32 is suppressed. The temperature of the high heat conductive member 32 is, for example, about 50 ° C. to 100 ° C. (see FIG. 6), and can be lower than the temperature of the mounting portion 41 (for example, about 150 ° C. to 300 ° C.). By suppressing the temperature rise of the high heat conductive member 32, heat transfer from the low heat conductive member 31 to the high heat conductive member 32 is promoted, and heat is transferred to the high heat conductive member 32, so that the heat is transferred from the low heat conductive member 31 to the adapter 1. The amount of heat can be reduced.

  Moreover, the high heat conductive member 32 is provided in a shape penetrating both ends in the short direction of the low heat conductive member 31, and all the both ends 323 (see FIG. 6) in the short direction of the high heat conductive member 32 are the low heat conductive member. Therefore, heat transfer from the low heat conductive member 31 to the high heat conductive member 32 can be promoted. Furthermore, since the high heat conductive member 32 is in contact with the outside air at two positions, heat dissipation to the outside air can be promoted.

  Furthermore, the high heat conductive members 32 are arranged at four locations in the heat insulating member 3, specifically, on the left and right sides of the central through hole 341, and further below the heat insulating member 3. Since it is also arranged on the side (exhaust pipe 4 side) and the upper side (adapter 1 side), that is, on each of the upper, lower, left and right parts of the heat insulating member 3, heat can be radiated in each part of the heat insulating member 3.

  Further, convex portions 332 and 334 are partially formed on the front surface 331 and the back surface 333 of the seal member 33, and the mating surfaces (the end surface 16 of the adapter 1, the attachment of the exhaust pipe 4 are formed by the convex portions 332 and 334. Since the surface 42 and the surfaces 311 and 312) of the low thermal conductive member 31 are brought into contact with each other, the contact area between the seal member 33 and the mating surface is reduced as compared with the configuration having no projection as shown in FIG. be able to. And a contact surface pressure which is a contact pressure with the sealing member 33 and the other party surface can be increased because a contact area reduces. Therefore, it is possible to effectively prevent the exhaust gas from leaking to the outside from between the exhaust pipe 4 and the heat insulating member 3, between the heat insulating member 3 and the adapter 1, or between the low heat conducting member 31 and the seal member 33. The sealing performance of 33 can be improved.

  Further, the contact area between the heat insulating member 3 and the exhaust pipe 4 can be reduced by the convex portion 332 formed on the lower seal member 33. By reducing the contact area, heat transfer from the exhaust pipe 4 to the heat insulating member 3 can be suppressed, and consequently heat transfer from the exhaust pipe 4 to the adapter 1 and the injection valve 2 can be suppressed. Similarly, the contact area between the heat insulating member 3 and the adapter 1 can be reduced by the convex portion 332 formed on the upper seal member 33. By reducing the contact area, heat transfer from the heat insulating member 3 to the adapter 1 and the injection valve 2 can be suppressed.

  Further, since the air layer 35 having a low thermal conductivity is formed between the seal member 33 and the low heat conductive member 31 by the convex portion 334 formed on the back surface 333 of the seal member 33, It is possible to suppress the heat transmitted to the seal member 33 from being transmitted to the low heat conductive member 31. Similarly, heat transfer from the low heat conductive member 31 to the upper seal member 33 can be suppressed. As described above, the air layer 35 is interposed in the thickness direction of the heat insulating member 3, so that heat can be prevented from being transmitted in the thickness direction, and hence heat transfer from the exhaust pipe 4 to the adapter 1 and the injection valve 2 can be suppressed. it can. In particular, since the high heat conduction member 32 is disposed on the surfaces 311 and 312 of the low heat conduction member 31 and the air layer 35 is formed at a position in contact with the high heat conduction member 32, the contact area between the high heat conduction member 32 and air is reduced. The temperature increase of the high heat conductive member 32 can be effectively suppressed.

  Further, since at least a part of the high heat conductive member 32 is disposed at a position facing the concave portion 17 (see FIG. 1), the heat transferred to the high heat conductive member 32 is transferred to the end face 16 of the adapter 1. Can be suppressed.

  Moreover, since the heat insulation member 3 is formed vertically symmetrical (symmetric with respect to the plane 100 in FIG. 3), it can be assembled regardless of which surface of the heat insulation member 3 is on the adapter 1 side. Furthermore, since the heat insulation member 3 is formed symmetrically (symmetric with respect to the plane 101 in FIG. 3), it can be assembled regardless of which of the two side portions 3 b of the heat insulation member 3 is on the right side. Thus, the assembly property of the heat insulation member 3 can be improved because the heat insulation member 3 is formed in a vertically and laterally symmetrical shape.

  Here, FIG. 7 and FIG. 8 show experimental results showing the effects of the present embodiment. Specifically, FIG. 7 shows the amount of heat transfer to the adapter 1 when the heat insulating member 3c (see FIG. 9) having a configuration in which the convex portions 332 and 334 are omitted from the heat insulating member 3 of the present embodiment is used. The amount of heat transfer to the adapter 1 in the case where a heat insulating member having a configuration in which the high heat conductive member 32 is further omitted from the heat insulating member 3c of FIG. 9 is used is shown on the right side. As shown in FIG. 7, the heat transfer amount is 100 W when there is no high heat conduction member 32, whereas the heat transfer amount is reduced to 77.5 W when there is the high heat conduction member 32.

  Further, FIG. 8 shows the amount of heat transfer to the adapter 1 on the left side when the heat insulating member 3 (with the high heat conduction member 32 and with the protrusions 332 and 334) of the present embodiment is used. The amount of heat transfer to the adapter 1 in the case where a heat insulating member having a configuration in which both of the convex portions 332 and 334 are omitted is shown on the right side. As shown in FIG. 8, when both the high heat conduction member 32 and the convex portions 332 and 334 are not provided, the heat transfer amount is 100 W, whereas both the high heat conduction member 32 and the convex portions 332 and 334 are provided. The heat transfer amount is reduced to 66.3W. Further, comparing the result on the left side of FIG. 7 with the result on the left side of FIG. 8, the heat transfer amount is reduced from 77.5 W to 66.3 W by providing the convex portions 332 and 334.

(Modification)
In addition, this invention is not limited to the said embodiment, A various change is possible to the limit which does not deviate from description of a claim. For example, in the said embodiment, although the example which attaches an adapter and a heat insulation member to an exhaust pipe in two places was shown, you may attach to an exhaust pipe in what places.

  FIG. 10 shows a plan view of a heat insulating member 3d in which attachment portions to the exhaust pipe are formed at three locations. In FIG. 10, the same reference numerals are given to the same parts as those in the above embodiment. The heat insulating member 3d is formed in a substantially triangular shape in plan view. Near the center of the heat insulating member 3d, a tip protruding portion of the adapter, a part on the tip side of the injection valve, and a through hole 341 in which the plate member is disposed are formed. Bolt insertion holes 342 for attaching to the exhaust pipe are formed in the vicinity of each vertex in the triangle of the heat insulating member 3d. That is, bolt insertion holes 342 are formed at three locations.

  Except for the number of bolt insertion holes 342, the present embodiment is the same as the above embodiment. That is, the high heat conduction member 32 is disposed between each bolt insertion hole 342 and the central through hole 341. A convex portion 332 is partially formed on the surface of the seal member 33. The convex portion 332 is formed around each of the through holes 341 and 342 as in the above embodiment. The adapter also has a plan view shape similar to that of the heat insulating member 3d. Also by this, the same effect as the above embodiment can be obtained.

  Moreover, like the heat insulation member 3e shown in FIG. 11, the high heat conductive member 36 may be provided so that a part 361 may protrude from the low heat conductive member 31. The high heat conductive member 36 has protrusions 361 that penetrate both ends of the low heat conductive member 31 in the short direction of the low heat conductive member 31 and protrude further laterally from the both ends. Each protrusion 361 is in contact with the outside air. According to this, since the part in contact with the outside air of the high heat conductive member can be increased, the heat insulating member can be radiated more easily.

  In the above embodiment, the example in which the high heat conductive member is disposed on the surface of the low heat conductive member has been described. However, even if the high heat conductive member is inserted into the low heat conductive member so that both surfaces of the high heat conductive member are not exposed. good. Also in this case, if a part of the high thermal conductivity member is brought into contact with the outside air, the same effect as the above embodiment can be obtained.

  Moreover, in the said embodiment, in order to make a heat insulation member into a symmetrical shape, although the high heat conductive member and the convex part were symmetrically arranged, the heat insulation member may be a shape asymmetric with respect to up and down, right and left, that is, The high heat conductive member and the convex portion may be arranged asymmetrically. Moreover, the high heat conductive member should just be arrange | positioned at at least one place. In addition, the shape of the high heat conductive member does not need to be a plate shape as described above, and may be any shape such as a round bar shape.

  Moreover, although the example which provided the convex part in the sealing member was demonstrated in the said embodiment, you may abbreviate | omit a convex part. Even in this case, the amount of heat transfer to the adapter can be reduced as compared with the conventional configuration without a high heat conducting member (see FIG. 7). Moreover, a seal member can be easily manufactured by omitting the convex portion.

  Furthermore, the convex portion may be formed on the surface of the mating surface that contacts the seal member, that is, the convex portion is formed on the mounting surface of the exhaust pipe, the end surface of the adapter, the surface of the low heat conductive member or the high heat conductive member. May be. This can also improve the seal surface pressure and reduce the contact area between the heat insulating member and the exhaust pipe or adapter.

1 Adapter (housing member)
2 Injection valve 3, 3c, 3d, 3e Heat insulation member 4 Exhaust pipe 31 Low heat conduction member 32, 36 High heat conduction member

Claims (8)

An exhaust valve (2) for injecting an additive into an exhaust pipe (4) of an internal combustion engine, and is provided between the exhaust pipe and a housing member (1) attached to the exhaust pipe;
A low thermal conductivity member (31) having a lower thermal conductivity than the housing member;
A part of the low heat conductive member (321, 361) is provided so as to be in contact with the outside air, and a high heat conductive member (32, 36) having a higher thermal conductivity than the low heat conductive member;
A heat insulating member (3, 3c, 3d, 3e) characterized by comprising:   Seal members (33) disposed on both the surface (311) facing the housing member side and the surface (312) facing the exhaust pipe side of the low heat conduction member and suppressing leakage of exhaust gas to the outside. The heat insulating member according to claim 1, wherein the heat insulating member is in contact with the housing member and the exhaust pipe.   The seal member has a convex portion (332) on a surface (331) facing the accommodating member or the exhaust pipe, and the convex portion contacts the accommodating member or the exhaust pipe. The heat insulating member (3, 3d, 3e) according to claim 2.   The said sealing member has a convex part (334) in the surface (333) which faced the said low heat conductive member side, The convex part contacts the said low heat conductive member or the said high heat conductive member, It is characterized by the above-mentioned. Item 4. The heat insulating member (3, 3d, 3e) according to item 2 or 3. A recess (17) is formed on a surface (16) of the housing member facing the heat insulating member,
The heat insulating member according to claim 1, wherein at least a part of the high heat conductive member is provided at a position facing the concave portion. The direction between the surface of the heat insulating member facing the exhaust pipe and the surface facing the housing member is the thickness direction,
The said high heat conductive member was provided in the form penetrated between the both ends (314,315) of the said low heat conductive member in the direction orthogonal to the said thickness direction, The any one of Claims 1-5 characterized by the above-mentioned. The heat insulating member according to item.   The said high heat conductive member (36) is provided so that a part (361) may protrude from the said low heat conductive member, The part is in contact with external air, The any one of Claims 1-6 characterized by the above-mentioned. The heat insulating member (3e) described in 1. The direction between the surface of the heat insulating member facing the exhaust pipe and the surface facing the housing member is the thickness direction,
The said heat insulation member was formed in the shape symmetrical with respect to the plane (100) orthogonal to the said thickness direction, The heat insulation member of any one of Claims 1-7 characterized by the above-mentioned.

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