Patent Application
20190112970
The present disclosure relates to an exhaust system apparatus for an internal combustion engine.
The exhaust system apparatus described in Japanese Laid-Open Patent Publication No. 2004-124767 has an exhaust conduit, which is connected to the engine body of an internal combustion engine and allows exhaust gas flows to flow therethrough. The exhaust conduit is curved into a U-shaped. The exhaust conduit has one end connected to the front face of the engine body and extends from that end to the rear of the vehicle by passing the side of the engine body. The exhaust system apparatus described in the above publication has a heat shield plate, which covers the curved portion of the exhaust conduit. The heat shield plate includes an upper plate portion and a lower plate portion. The upper plate portion includes an upper body portion having a semicircular cross-sectional shape and a pair of upper flanges extending radially outward from the opposite ends in the circumferential direction of the upper body portion. The lower plate portion includes a lower body portion having a semicircular cross-sectional shape and a pair of lower flanges extending radially outward from the opposite ends in the circumferential direction of the lower body portion. With the upper flange and the lower flange abutting against each other, the outer circumferential surfaces of the upper plate portion and the lower plate portion are clamped with an annular band, so that a heat shield plate having a circular cross-sectional shape is provided.
In the exhaust system apparatus described in the above publication, the exhaust conduit is connected to the front face of the engine body, which is located on the front side in the front-rear direction of the vehicle. In contrast, if the exhaust conduit is connected to the rear face of the engine body, which is located on the rear side in the front-rear direction of the vehicle, it is necessary to take countermeasures against the heat different from those of the exhaust system apparatus described in the above-mentioned publication.
In accordance with one aspect of the present disclosure, an exhaust system apparatus for an internal combustion engine mounted on a vehicle is provided. The internal combustion engine includes an engine body having a rear face located on a rear side in a front-rear direction of the vehicle. The exhaust system apparatus includes an exhaust conduit member, which is configured to be connected to the rear face of the engine body and allow exhaust gas to flow inside, a heat shield member, which covers the exhaust conduit member. The exhaust conduit member includes a curved portion. A region on an inner peripheral side of the curved portion is an inner peripheral region. A region on an outer peripheral side of the curved portion is an outer peripheral region. The heat shield member has a curved-side body portion, which covers the curved portion, an inner flange portion, which extends from the curved-side body portion and is arranged in the inner peripheral region, and an outer flange portion, which extends from the curved-side body portion and is arranged in the outer peripheral region. An extending length of the inner flange portion in a direction away from the curved-side body portion is longer than an extending length of the outer flange portion in a direction away from the curved-side body portion.
Other aspects and advantages of the present disclosure will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating exemplary embodiments.
The disclosure may be understood by reference to the following description together with the accompanying drawings:
An exhaust system apparatus for an internal combustion engine according to one embodiment will now be described with reference to
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The compressor housing 31 is located at the left end (the left end as viewed in
An intake conduit 40, which is a component of the intake passage, is connected to the compressor housing 31. The intake conduit 40 has a tubular intake main conduit 41, through which intake air flows, and a connecting flange portion 42, which is provided at the end of the intake main conduit 41 on the downstream side in the intake flow (the right end as viewed in
The bearing housing 32 has a columnar outer shape that extends in the vehicle width direction. The bearing housing 32 has inside an accommodation space, which accommodates a bearing (not shown). The bearing rotationally supports a rotary shaft having a first end connected to the compressor. A lubricant supply tube 51 for supplying lubricant to the bearing is connected to the bearing housing 32. A coolant supply tube 52 for supplying coolant to the bearing housing 32 is connected to the bearing housing 32. The end of the lubricant supply tube 51 connected to the bearing housing 32 and the end of the coolant supply tube 52 connected to the bearing housing 32 are fitted in a single support plate 53. The support plate 53 is an elliptical plate extending in the up-down direction of the vehicle and is arranged along the outer circumferential surface of the bearing housing 32. The support plate 53 is fastened to the bearing housing 32 with fastening bolts 54, which are inserted through the opposite ends in the up-down direction of the support plate 53. This fixes the lubricant supply tube 51 and the coolant supply tube 52 to the bearing housing 32 so as not to be detached therefrom.
The turbine housing 33 is located to the right of the bearing housing 32 and has a right end portion, which is arranged across the first center line L1. The turbine housing 33 has a turbine accommodating portion 34, which is connected to the bearing housing 32, an exhaust discharge portion 35, which is provided on the downstream side in exhaust gas flow (the right side as viewed in
The turbine accommodating portion 34 is connected to the rear face of the engine body 21. The rear face of the engine body 21 is the surface of the engine body 21 that is located on the rear side (or facing rearward) in the vehicle front-rear direction. Exhaust gas discharged from the engine body 21 flows into the turbine accommodating portion 34. The turbine accommodating portion 34 is longer in the vehicle up-down direction than the bearing housing 32. In the vehicle up-down direction, the upper end of the turbine accommodating portion 34 is arranged at the same position as the upper end of the bearing housing 32, and the lower end of the turbine accommodating portion 34 is arranged below the lower end of the bearing housing 32. The turbine accommodating portion 34 has an accommodation space, which accommodates a turbine (not shown). A second end of the above-mentioned rotary shaft is connected to the turbine. The exhaust gas drawn in from the engine body 21 rotates the turbine. Since the turbine and the compressor are connected to each other by the rotary shaft, the compressor rotates as the turbine rotates.
The exhaust discharge portion 35 has a cylindrical shape that extends in the vehicle width direction. The left end of the exhaust discharge portion 35, which is adjacent to the turbine accommodating portion 34, has the same shape as the right end of the turbine accommodating portion 34, which is adjacent to the exhaust discharge portion 35. The exhaust discharge portion 35 has a diameter that decreases as the distance from the turbine accommodating portion 34 increases. The turbine large-diameter portion 36 includes a left flare portion 36A, which is adjacent to the exhaust discharge portion 35, a central large-diameter portion 36B, which is provided on the downstream side of the left flare portion 36A, and a right flare portion 36C, which is provided on the downstream side of the central large-diameter portion 36B. The outer diameter of the central large-diameter portion 36B is larger than the outer diameter at the right end of the exhaust discharge portion 35. Also, the outer diameter of the central large-diameter portion 36B is smaller than the outer diameter at the left end of the exhaust discharge portion 35. The left flare portion 36A has a diameter that increases toward the downstream side. The outer diameter of the left end of the left flare portion 36A is equal to the outer diameter at the right end of the exhaust discharge portion 35, and the outer diameter at the right end of the left flare portion 36A is equal to the outer diameter of the central large-diameter portion 36B. The right flare portion 36C has a diameter that decreases toward the downstream side. The outer diameter of the left end of the right flare portion 36C is equal to the outer diameter of the central large-diameter portion 36B, and the outer diameter at the right end of the right flare portion 36C is equal to the outer diameter at the right end of the exhaust discharge portion 35, that is, the outer diameter at the left end of the left flare portion 36A.
The exhaust flow portion 37 has a cylindrical shape that extends in the vehicle width direction. The exhaust flow portion 37 has a funnel-like outer shape, the diameter of which decreases toward the downstream side. The upper end of the exhaust flow portion 37 is inclined so as to descend toward the downstream side.
The exhaust conduit connecting portion 38 is inclined with respect to the vehicle up-down direction so as to be progressively shifted to the left toward the upper end. The exhaust conduit connecting portion 38 includes a first flare portion 38A, which is arranged on the upstream side in exhaust gas flow, and a connecting annular portion 38B, which is provided on the downstream side in exhaust gas flow of the first flare portion 38A. The outer diameter of the connecting annular portion 38B is larger than the outer diameter of the central large-diameter portion 36B of the turbine large-diameter portion 36. The upper end of the connecting annular portion 38B is located above the upper end of the central large-diameter portion 36B, and the lower end of the connecting annular portion 38B is located below the lower end of the central large-diameter portion 36B. The first flare portion 38A has a diameter that increases toward the right end, which is adjacent to the connecting annular portion 38B. The outer diameter at the left end of the first flare portion 38A is equal to the outer diameter at the right end of the exhaust flow portion 37, and the outer diameter at the right end of the first flare portion 38A is equal to the outer diameter of the connecting annular portion 38B. An exhaust conduit 60 is connected to the end on the downstream side of the turbine housing 33.
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The turbine connecting portion 61 includes a tubular insertion portion 62 and a second flare portion 63. The second flare portion 63 includes an upstream annular portion 63A, which constitutes the end on the upstream side (the left side as viewed in
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The sensor mount 65 has a sensor large-diameter portion 71, which is provided on the downstream side of the sensor mount main portion 66. The sensor large-diameter portion 71 has a cylindrical shape that extends in the extending direction of the central axis L3. The outer diameter of the sensor large-diameter portion 71 is larger than the outer diameter of the sensor mount main portion 66.
The first catalyst support portion 75 has a cylindrical shape that extends in the extending direction of the central axis L3. The outer diameter of the first catalyst support portion 75 is smaller than the outer diameter of the sensor mount main portion 66 of the sensor mount 65. The first catalyst support portion 75 accommodates a catalyst (not shown) for purifying exhaust gas. The bracket 80 is fixed to the lower part of the first catalyst support portion 75. The bracket 80 has a plate-shape and includes a bracket base 81, which is connected to the first catalyst support portion 75, and a bracket connecting portion 82, which extends from the bracket base 81. The bracket connecting portion 82 extends rightward with respect to the bracket base 81. That is, the bracket 80 has an L-shape when viewed from the rear of the vehicle. The bracket connecting portion 82 an elliptic or oblong connecting hole 82A, which extends in the vehicle width direction, at the left end.
As shown in
When attaching the exhaust conduit 60 to the engine body 21, the second support pillar 148 of the second stay 146 is first inserted through the connecting hole 82A of the bracket 80. The center of gravity of the whole exhaust conduit 60 is present at a position different from the bracket 80. Thus, when the second support pillar 148 is inserted through the connecting hole 82A, so that the exhaust conduit 60 is supported by the second support pillar 148, the exhaust conduit 60 is inclined due to its own weight, so that the opening of the turbine connecting portion 61 faces the opening of the exhaust conduit connecting portion 38 of the turbine housing 33. By attaching the second nut 149 to the second support pillar 148, the bracket 80 is fastened to the second stay 146. As a result, the exhaust conduit 60 is attached to the engine body 21. The thickness of the bracket 80 is greater than that of the exhaust conduit 60.
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The inner diameter of the upstream end of the upstream flare portion 86A is equal to the outer diameter of the first catalyst support portion 75. When the right end of the first catalyst support portion 75 is inserted into the interior of the upstream flare portion 86A, the inner circumferential surface of the upstream flare portion 86A and the outer circumferential surface of the right end of the first catalyst support portion 75 come into contact. In this state, the curved shape portion 85 and the first catalyst support portion 75 are joined together, for example, by welding, so that the curved shape portion 85 and the first catalyst support portion 75 are connected to each other. The upper part of the outer circumferential surface of the upstream flare portion 86A is recessed downward, so that the upstream flare portion 86A has a shape the diameter of which decreases toward the downstream side. The first curved portion 86B is curved such that the end on the downstream side opens downward. That is, the first curved portion 86B causes exhaust gas flowing in the extending direction of the central axis L3 to flow downward.
The second support lug portion 87 extends upward from the outer circumferential surface on the upper side of the first curved portion 86B. The second support lug portion 87 has a cylindrical shape. The interior of the second support lug portion 87 communicates with the interior of the first curved portion 86B. As shown in
The cylindrical second curved conduit 88 includes a lower conduit portion 88A, which extends downward, a second curved portion 88B, which is provided on the downstream side of the lower conduit portion 88A, and a lateral conduit portion 88C, which is provided on the downstream side of the second curved portion 88B. The inner diameter of the lower conduit portion 88A is equal to the outer diameter of the end on the downstream side of the first curved portion 86B. When the end on the downstream side of the first curved portion 86B is inserted into the interior of the lower conduit portion 88A, the inner circumferential surface of the lower conduit portion 88A and the outer circumferential surface of the first curved portion 86B come into contact. In this state, the lower conduit portion 88A and the first curved portion 86B are joined together, for example, by welding, so that the second curved conduit 88 and the first curved conduit 86 are connected to each other. The second curved portion 88B is curved such that the end on the downstream side opens leftward. That is, the second curved portion 88B causes the exhaust gas flowing downward from the first curved portion 86B toward the lower conduit portion 88A to flow leftward in the vehicle width direction. The lateral conduit portion 88C has a cylindrical shape that extends in the vehicle width direction. The first curved conduit 86 and the second curved conduit 88 are arranged in the up-down direction. As described above, the curved shape portion 85 has a curved shape causes the flow of exhaust gas flowing through the first catalyst support portion 75 and rightward to flow downward first and then leftward. As shown in
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The catalyst accommodating portion 92 includes a cylindrical accommodating main conduit 104, which extends rearward, a first fixing lug 93, which extends from the outer circumferential surface of the accommodating main conduit 104, a second fixing lug 97, and a third fixing lug 105 shown in
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The first stay 140 includes a stay portion 150, which extends rearward from the rear end face of the first base 141, that is, from the rear end faces of the lower leg portion 142 and the connecting leg portion 144. The stay portion 150 has a triangular base 151, which has a triangular shape as viewed from the right side of the vehicle. The lower end of the triangular base 151 is located below the lower leg portion 142 of the first base 141. The lower end face of the triangular base 151 extends toward the rear of the engine body 21. The upper end face of the triangular base 151 is inclined so as to descend toward the rear end. The stay portion 150 has a columnar first support pillar 152, which extends rearward from the triangular base 151.
The third fixing lug 105, which is provided on the second catalyst support portion 90 extends downward from the accommodating main conduit 104. As shown in
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The connecting flange portion 162 has a flat plate shape the outer shape of which is the same as the outer shape of the exhaust pipe connecting portion 110. The thickness of the connecting flange portion 162 is equal to the thickness of the exhaust pipe connecting portion 110. The connecting flange portion 162 has a second abutting annular portion 163 and a pair of second extended flange portions 164, which are provided at the opposite ends in the vehicle width direction of the second abutting annular portion 163. The pair of second extended flange portions 164 includes a second right flange portion 164A, which extends rightward from the second abutting annular portion 163, and a second left flange portion 164B, which extends leftward from the second abutting annular portion 163. The second right flange portion 164A and the second left flange portion 164B are arranged at an angular interval of 180° in the circumferential direction. The second right flange portion 164A and the second left flange portion 164B have a shape that tapers as the distance from the second abutting annular portion 163 increases. Each of the second right flange portion 164A and the second left flange portion 164B has a second bolt insertion hole 168. The second abutting annular portion 163 contacts the first abutting annular portion 111, the second right flange portion 164A contacts the first right flange portion 112A, and the second left flange portion 164B contacts the first left flange portion 112B. Then, nuts (not shown) are screwed to the fastening bolts 115 inserted through the first bolt insertion holes 113 and the second bolt insertion holes 168 to fasten the exhaust pipe connecting portion 110 and the connecting flange portion 162 to each other, so that the front pipe 161 is connected to the exhaust conduit 60.
The diameter reduction pipe 165, which has a cylindrical shape, extends from the periphery of the opening in the second abutting annular portion 163 of the connecting flange portion 162. The diameter of the diameter reduction pipe 165 decreases toward the downstream side. The first pipe 166 has a cylindrical shape. The first pipe 166 has a constant outer diameter equal to that at the downstream end of the diameter reduction pipe 165. The first pipe 166 is arranged to descend toward the downstream side. The second pipe 167 has a cylindrical shape. The outer diameter of the second pipe 167 is equal to the inner diameter of the first pipe 166. When the upstream end the second pipe 167 is inserted into the interior of the first pipe 166, the inner circumferential surface of the first pipe 166 and the outer circumferential surface of the second pipe 167 come into contact with each other. In this state, the first pipe 166 and the second pipe 167 are joined to each other, for example, by welding. The upstream end of the second pipe 167 is located in the engine compartment 10, and the second pipe 167 extends outward from the engine compartment 10. The second pipe 167 extends to the bottom of the vehicle through under the dashboard (not shown). In the lower part of the vehicle, the downstream end of the second pipe 167 is connected to the center pipe. The downstream end of the center pipe is connected to the tail pipe. The tail pipe opens at the rear end of the vehicle. The exhaust gas discharged from the engine body 21 to the turbine housing 33 passes through the exhaust conduit 60 and the exhaust pipe 160 and is emitted to the outside of the vehicle.
In the present embodiment, the turbine housing 33 of the forced-induction device 30, the exhaust conduit 60, which is connected to the downstream end of the turbine housing 33, and the exhaust pipe 160 constitute the exhaust conduit member in the exhaust system apparatus of the internal combustion engine. Also, as shown in
In the rear view shown in
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The left-side wall cover 187 extends upward from the left end of the cover main body 182. The left-side wall cover 187 is provided continuously from the front end to the rear end of the cover main body 182. In the left-side wall cover 187, the height of the center portion extending upward from the boundary between the front body portion 183 and the middle body portion 184 is the lowest, and the height from the cover main body 182 increases toward the front side and thereafter side. That is, the left-side wall cover 187 is configured such that the upright height of the portion extending upward from the middle body portion 184 is lower than the upright height of the portion extending upward from the rear body portion 185 in the cover main body 182. The right-side wall cover 186 and the left-side wall cover 187 restrict the movement in the vehicle width direction of the relative wind flowing over the cover main body 182.
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The upper cover 190 includes a first horizontal cover portion 193, which extends horizontally rearward from the rear end of the first inclined cover portion 192, and a vertical cover portion 194, which extends downward from the rear end of the first horizontal cover portion 193. The lower end of the vertical cover portion 194 is arranged at the same position in the up-down direction as the upper end of the cover main body 182 in the air guide cover 181. The upper cover 190 has a second horizontal cover portion 195, which extends horizontally rearward from the lower end of the vertical cover portion 194. The lower end face of the second horizontal cover portion 195 is arranged at the same position in the up-down direction as the upper end of the cover main body 182. Also, the rear end of the second horizontal cover portion 195 is located rearward of the first catalyst support portion 75 of the exhaust conduit 60. The upper cover 190 includes a second inclined cover portion 196, which extends diagonally downward from the rear end of the second horizontal cover portion 195, and a third horizontal cover portion 197, which extends horizontally rearward from the rear end of the second inclined cover portion 196. The lower end of the third horizontal cover portion 197 is located above the rear body portion 185 of the cover main body 182.
A rear cover 200 has a plate shape that extends an adequate length in the vehicle width direction. The rear cover 200 is arranged rearward of the first catalyst support portion 75 of the exhaust conduit 60. The rear cover 200 includes a first upright cover portion 201, which extends in the up-down direction, a second upright cover portion 202, which is arranged below and rearward of the first upright cover portion 201 and extends in the up-down direction, and a rear inclined cover portion 203, which connects the rear end of the first upright cover portion 201 and the upper end of the second upright cover portion 202.
The upper end of the first upright cover portion 201 is located at the same position in the up-down direction as the lower end of the third horizontal cover portion 197 of the upper cover 190. Also, the first upright cover portion 201 is located below the second inclined cover portion 196 and is arranged forward of the third horizontal cover portion 197. The lower end of the first upright cover portion 201 is arranged at the same position in the up-down direction as the lower end of the rear body portion 185 of the cover main body 182. The rear inclined cover portion 203 is inclined so as to descend toward the rear end. The lower end of the rear inclined cover portion 203 is located below the upper end of the first catalyst support portion 75 of the exhaust conduit 60. The lower end of the second upright cover portion 202 is arranged between the first catalyst support portion 75 and the lateral conduit portion 88C of the exhaust conduit 60 in the up-down direction.
A dashboard 210 is provided on the rear side of the air guide cover 181, the upper cover 190, and the rear cover 200. The dashboard 210 separates the engine compartment 10 and the passenger compartment 240 from each other. The dashboard 210 has a partition wall portion 211, which extends in the up-down direction. The partition wall portion 211 extends from a position above the upper cover 190 to a position of the same height as the lower end of the first catalyst support portion 75 of the exhaust conduit 60. The dashboard 210 has a first inclined wall 212, which extends obliquely downward from the lower end of the partition wall portion 211. The first inclined wall 212 is inclined so as to be progressively shifted to the front toward the lower end. The dashboard 210 has a first upright wall 213, which extends downward from the lower end of the first inclined wall 212. The first upright wall 213 extends to a position below the first catalyst support portion 75. The dashboard 210 has a second inclined wall 214, which extends downward from the lower end of the first upright wall 213. The second inclined wall 214 is inclined so as to be progressively shifted to the front toward the lower end. The dashboard 210 has a second upright wall 215, which extends downward from the lower end of the second inclined wall 214. The second upright wall 215 extends to a position below the rear cover 200. The dashboard 210 has a third inclined wall 216, which extends downward from the lower end of the second upright wall 215. The third inclined wall 216 is inclined so as to be progressively shifted to the front toward the lower end. The third inclined wall 216 extends to a position forward of the rear end face of the second upright cover portion 202 of the rear cover 200. The dashboard 210 has a fourth inclined wall 217, which extends downward from the lower end of the third inclined wall 216. The fourth inclined wall 217 is inclined so as to be progressively shifted to the rear toward the lower end. The dashboard 210 has a cylindrical wall portion 218, which protrudes from the lower end of the fourth inclined wall 217 toward the passenger compartment 240. The cylindrical wall portion 218 includes a flare tube portion 218A, the diameter of which increases toward the passenger compartment 240, and a flare tube portion 218B, which extends from the flare tube portion 218A such that the diameter decreases toward the passenger compartment 240.
The dashboard 210 has a first curved wall 219, which extends downward in a curved manner from the lower end of the cylindrical wall portion 218. The first curved wall 219 is curved so as to protrude toward the engine compartment 10, and the lower end of the first curved wall 219 is located rearward of the upper end of the first curved wall 219. The first curved wall 219 extends to a position below the lateral conduit portion 88C of the exhaust conduit 60. The dashboard 210 has a second curved wall 220, which extends downward in a curved manner from the lower end of the first curved wall 219, and a third curved wall 221, which extends downward in a curved manner from the lower end of the second curved wall 220. The second curved wall 220 is curved so as to protrude toward the engine compartment 10, and the lower end of the second curved wall 220 is located rearward of the upper end of the second curved wall 220. Also, the third curved wall 221 is curved so as to protrude toward the engine compartment 10, and the lower end of the third curved wall 221 is located rearward of the upper end of the third curved wall 221. A floor panel 222 extends rearward from the lower end of the third curved wall 221. The exhaust pipe 160 described above passes under the floor panel 222 and extends rearward.
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As indicated by the arrows in
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The rear split part 266 includes a rear covering portion 267, which is curved along the outer circumferential surface of the rear semicircular portion of the exhaust conduit 60 to cover the rear semicircular portion, and an outer rear flange 268, which extends from the rear covering portion 267 toward the outer peripheral region of the exhaust conduit 60. The rear split part 266 also has an inner rear flange 269, which extends from the rear covering portion 267 toward the inner peripheral region R of the exhaust conduit 60. As shown in
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In such a state, the upstream insulator 261 is constituted by causing by joining the outer front joint portions 264A and the outer rear joint portions 268A to each other and joining the inner front joint film portions 265A and the inner rear joint portions 269A to each other. The proximal ends of the outer front joint portions 264A and the outer rear joint portions 268A are crimped together, and the distal ends are spot-welded together, so that the joint portions 264A and 268A are joined together. The extending lengths of the outer front joint portions 264A and the outer rear joint portions 268A are set to lengths required to join the front split part 262 and the rear split part 266 to constitute the upstream insulator 261. Likewise, the proximal ends of the inner front joint film portion 265A and the inner rear joint portions 269A are crimped together, and the distal ends are welded together, so that the inner front joint film portion 265A and the inner rear joint portions 269A are joined together. The extending length of the outer front joint portions 264A is set to a length required to join the front split part 262 and the rear split part 266 to constitute the upstream insulator 261. Also, the extending length of the inner front joint film portion 265A is set to be longer than the required length.
In the upstream insulator 261, the front covering portion 263 and the rear covering portion 267 constitute a curved-side body portion 280, which covers the curved portion. In the upstream insulator 261, the inner front flange 265 and the inner rear flange 269 constitute an inner flange portion 285, which extends from the curved-side body portion 280 and is arranged in the inner peripheral region R. As shown in
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The second upper flange 304 is located on the right side at the downstream end of the upper covering portion 302 and extends forward along the support flare portion 108 and the catalyst accommodating portion 92. The front portion of the second upper flange 304 extends in the vehicle width direction along the exhaust inflow portion 91. The second upper flange 304 has a second upper joint portion 304A at the front end and the rear end. The extending length of each second upper joint portion 304A in a direction away from the upper covering portion 302, that is, the protruding length from the upper covering portion 302 is partially increased.
The lower split part 305 has a lower covering portion 306, which is curved along the outer circumferential surface of the lower semicircular portion of the exhaust conduit 60 to cover the lower semicircular portion. As shown in
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The turbine-side insulator 320 has a first body portion 321, which covers the turbine accommodating portion 34 and the exhaust discharge portion 35, and a second body portion 322, which is provided to the right of the first body portion 321 and covers the turbine large-diameter portion 36. The turbine-side insulator 320 also has a third body portion 323, which is provided to the right of the second body portion 322 and covers the exhaust flow portion 37, a fourth body portion 324, which is provided to the right of the third body portion 323 and covers the exhaust conduit connecting portion 38 and the turbine connecting portion 61. Further, the turbine-side insulator 320 has a fifth body portion 325, which is provided to the right of the fourth body portion 324 and covers the sensor mount 65 of the exhaust conduit 60.
The first body portion 321 has a shape that is curved along the outer circumferential surfaces of the turbine accommodating portion 34 and the exhaust discharge portion 35. The first body portion 321 has a contact flange portion 321A, which extends behind the bearing housing 32. The left end of the contact flange portion 321A is arranged to the right of the left end of the bearing housing 32 and covers the right end of the bearing housing 32. The front end face of the contact flange portion 321A is in contact with the outer circumferential surface of the bearing housing 32. The contact flange portion 321A is fastened to the bearing housing 32 with a first fixing bolt 350. The contact flange portion 321A is shaped and arranged so as not to cover the support plate 53, which is fixed to the bearing housing 32, and is arranged in the lower portion of the first body portion 321. The first body portion 321 is thus unlikely to interfere with the lubricant supply tube 51 or the coolant supply tube 52, which are fixed to the support plate 53. The first body portion 321 has an upper covering flange portion 321B, which extends to cover the top of the bearing housing 32. The left end of the upper covering flange portion 321B is located to the right of the left end of the bearing housing 32 and to the left of the left end of the contact flange portion 321A.
The turbine-side insulator 320 has a first upper flange portion 326, which extends upward from the first body portion 321. The first upper flange portion 326 is provided continuously from the right end to the left end of the first body portion 321. The position of the upper end of the first upper flange portion 326 ascends from the left end toward the right end of the first upper flange portion 326 and is constant in a section above the turbine accommodating portion 34. Further, the position of the upper end of the first upper flange portion 326 is a step higher in a section above the exhaust discharge portion 35. The first upper flange portion 326 is fastened to the engine body 21 with a second fixing bolt 351 in a section above the boundary between the turbine accommodating portion 34 and the exhaust discharge portion 35.
The turbine-side insulator 320 has a first lower flange portion 331, which extends downward from the first body portion 321. The first lower flange portion 331 is provided continuously from the right end of the first body portion 321 to a middle position of the contact flange portion 321A. The lower end of the first lower flange portion 331 is located above the position of the upper end of the second catalyst support portion 90.
The second body portion 322 has a shape that is curved along the outer circumferential surface of the turbine large-diameter portion 36. The second body portion 322 has a larger diameter than that of the right end of the first body portion 321. The second body portion 322 constitutes a protrusion that protrudes further rearward than the right end of the first body portion 321 and extends in the up-down direction.
The turbine-side insulator 320 has a second upper flange portion 327, which extends upward from the second body portion 322. The second upper flange portion 327 is provided continuously from the right end to the left end of the second body portion 322. The upper end of the second upper flange portion 327 is at the same height as the upper end at the right end of the first upper flange portion 326 and extends horizontally. Also, the turbine-side insulator 320 has a second lower flange portion 332, which extends downward from the second body portion 322. The second lower flange portion 332 is provided continuously from the right end to the left end of the second body portion 322. The position of the lower end of the second lower flange portion 332 ascends from the left end toward the right end of the second lower flange portion 332 and is constant in a center portion of the second body portion 322.
The third body portion 323 has a shape that is curved along the outer circumferential surface of the exhaust flow portion 37. The third body portion 323 has a smaller diameter than that of the right end of the second body portion 322.
The turbine-side insulator 320 has a third upper flange portion 328, which extends upward from the third body portion 323. The third upper flange portion 328 is provided continuously from the right end to the left end of the third body portion 323. The position of the upper end of the third upper flange portion 328 is a step lower than the position of the upper end at the right end of the second upper flange portion 327 and is the same as the position of the upper end of the portion of the first upper flange portion 326 that is located above the turbine accommodating portion 34. Also, the turbine-side insulator 320 has a third lower flange portion 333, which extends downward from the third body portion 323. The third lower flange portion 333 is provided continuously from the right end to the left end of the third body portion 323. From the position corresponding to the right end of the second lower flange portion 332, the lower end of the third lower flange portion 333 descends toward the right end of the third lower flange portion 333.
The fourth body portion 324 has a shape that is curved along the outer circumferential surfaces of the exhaust conduit connecting portion 38 and the turbine connecting portion 61. The fourth body portion 324 has a larger diameter than that of the right end of the third body portion 323. The fourth body portion 324 constitutes a protrusion that protrudes further rearward than the third body portion 323 and extends in the up-down direction. The protruding amount of the fourth body portion 324 with respect to the third body portion 323 is greater than the protruding amount of the second body portion 322 with respect to the third body portion 323. As shown in
The turbine-side insulator 320 has a fourth upper flange portion 329, which extends upward from the fourth body portion 324. The fourth upper flange portion 329 is provided continuously from the right end to the left end of the fourth body portion 324. The position of the upper end of the fourth upper flange portion 329 is the same as the position of the upper end of the third upper flange portion 328. Also, the turbine-side insulator 320 has a fourth lower flange portion 334, which extends downward from the fourth body portion 324. The fourth lower flange portion 334 is provided continuously from the right end to the left end of the fourth body portion 324. From the left end of the fourth lower flange portion 334, the lower end of the fourth lower flange portion 334 descends toward the right end of the fourth lower flange portion 334. As shown in
The fifth body portion 325 has a shape that is curved along the outer circumferential surface of the turbine connecting portion 61 of the exhaust conduit 60. The fifth body portion 325 has an insertion hole for attaching the first sensor 171 to the first support lug portion 67. The insertion hole is provided in an upper part of the fifth body portion 325 and at a position corresponding to the first support lug portion 67. The fifth body portion 325 has a smaller diameter than that of the fourth body portion 324. In the vehicle width direction, the position of the right end of the fifth body portion 325 is the same as the position of the upstream end in the upstream insulator 261. In the right side view of the vehicle shown in
The turbine-side insulator 320 has a fifth upper flange portion 330, which extends upward from the fifth body portion 325. The fifth upper flange portion 330 is provided continuously from the right end to the left end of the fifth body portion 325. The position of the upper end at the left end of the fifth upper flange portion 330 is the same as the position of the upper end of the fourth upper flange portion 329. The position of the upper end of the fifth upper flange portion 330 descends toward the right end in a section above the sensor mount main portion 66, and then becomes constant. The position of the upper end at the right end of the fifth upper flange portion 330 is the same as the position of the upper end of of the left end of the first upper flange portion 326. The fifth upper flange portion 330 is fastened to the engine body 21 with a third fixing bolt 352 at a position above the sensor mount main portion 66.
The turbine-side insulator 320 has a fifth lower flange portion 335, which extends downward from the fifth body portion 325. The fifth lower flange portion 335 is provided continuously from the right end to the left end of the fifth body portion 325. From the left end of the fifth lower flange portion 335, the lower end of the fifth lower flange portion 335 descends toward the right end of the fifth lower flange portion 335. The fifth lower flange portion 335 has a lower cutout 335A in the upper part at the right end. The fifth lower flange portion 335 is fastened to the engine body 21 with a fourth fixing bolt 353 at a position below the portion in which the lower cutout 335A is provided. The fifth lower flange portion 335 is arranged in the inner peripheral region R of the exhaust conduit 60. In the up-down direction, a clearance exists between the fifth lower flange portion 335 and the downstream insulator 300. Also, in the vehicle width direction, a clearance exists between the fifth lower flange portion 335 and the bracket 80. The fifth lower flange portion 335 extends to a position below the bracket 80. The lower end of the fifth lower flange portion 335 is located below the upper end of the left end of the upstream insulator 261 in the inner flange portion 285.
In the turbine-side insulator 320, the first body portion 321, the second body portion 322, the third body portion 323, the fourth body portion 324, and the fifth body portion 325 constitute a turbine-side body portion 340, which covers the turbine housing 33. Also, in the turbine-side insulator 320, the first upper flange portion 326, the second upper flange portion 327, the third upper flange portion 328, the fourth upper flange portion 329, and the fifth upper flange portion 330 constitute a turbine-side upper flange portion 341A, which extends upward from the turbine-side body portion 340. The turbine-side upper flange portion 341A is arranged below the upper end face of the engine body 21. Also, in the turbine-side insulator 320, the first lower flange portion 331, the second lower flange portion 332, the third lower flange portion 333, the fourth lower flange portion 334, and the fifth lower flange portion 335 constitute a turbine-side lower flange portion 341B, which extends downward from the turbine-side body portion 340. The turbine-side upper flange portion 341A and the turbine-side lower flange portion 341B constitute a turbine-side flange portion 341, which extends from the turbine-side body portion 340. The fifth lower flange portion 335 in the turbine-side lower flange portion 341B is arranged in the inner peripheral region R of the exhaust conduit 60. That is, the turbine-side flange portion 341 is arranged in the inner peripheral region R of the exhaust conduit 60.
As shown in
As shown in
In
As shown in
The present embodiment has the following advantages.
(1) As indicated by the arrows in
When flowing around the exhaust conduit member or the heat shield member 250, the air receives heat from these components, which raises the temperature of the air. The air of the increased temperature flows and thus contributes to the temperature rise of the devices arranged around the exhaust conduit member. As shown by the arrow of long dashed short dashed line in
In the present embodiment, the heat shield member 250 (specifically, the upstream insulator 261) includes the inner flange portion 285, which is arranged in the inner peripheral region R, and the outer flange portion 290, which is arranged in the outer peripheral region of the curved portion. The inner flange portion 285 and the outer flange portion 290 function to combine and integrate the front split part 262 and the rear split part 266, which constitute the upstream insulator 261. In the upstream insulator 261, the extending length of the inner flange portion 285 is longer than the extending length of the outer flange portion 290. That is, the extending length of the inner flange portion 285 is longer than the length required to join the front split part 262 and the rear split part 266. The long extending length of the inner flange portion 285 hinders the air flowing around the exhaust conduit member from flowing to the inner peripheral region R. It is thus possible to positively cause the air flowing between the engine body 21 and the exhaust conduit 60 to flow downward. Thus, by setting a flow path for the air flowing around the exhaust conduit member in this manner, favorable countermeasures against heat, for example, suppression of heat input to the joint bushing 232 are provided. Therefore, in the configuration in which the exhaust conduit member is connected to the rear face of the engine body 21, it is possible to contribute to optimization of the countermeasure against heat.
Also, since the heat shield member 250, which suppresses heat transfer from the exhaust conduit member to the surrounding devices, is provided with the function of defining the air flow path, the number of components is reduced as compared to a case in which additional members are provided instead of the heat shield member 250.
(2) In the present embodiment, at the inner flange portion 285 of the upstream insulator 261, the opposite ends in the direction of the extending length of the portion arranged below the upstream flare portion 86A are supported by the curved-side body portion 280. Therefore, the vibration of the inner flange portion 285 is suppressed as compared with a configuration in which only one end in the extending direction of the inner flange portion 285 is supported by the curved-side body portion 280.
(3) The bracket 80, which is used to attach the exhaust conduit 60 to the engine body 21, is arranged in the inner peripheral region R of the exhaust conduit 60. Therefore, the bracket 80 hinders the air flowing around the exhaust conduit 60 from flowing into the inner peripheral region R. In this way, the bracket 80 and the inner flange portion 285 define the flow path of the air flowing around the exhaust conduit member. Accordingly, in the configuration in which the exhaust conduit member is connected to the rear face of the engine body 21, the present embodiment adds to the flexibility of the countermeasures against heat.
(4) In the present embodiment, the turbine-side flange portion 341 in the turbine-side insulator 320 is arranged in the inner peripheral region R in the exhaust conduit 60. Therefore, the turbine-side flange portion 341 hinders the air flowing around the exhaust conduit 60 from flowing into the inner peripheral region R. In this manner, in addition to the bracket 80 and the inner flange portion 285, the turbine-side flange portion 341 defines the flow path of the air flowing around the exhaust conduit member. Since the proportion occupied by one member can be reduced by employing a configuration in which three members are arranged in the inner peripheral region R, it is possible to suppress the generation of the vibration of the bracket 80, the inner flange portion 285, and the turbine-side flange portion 341.
(5) In the present embodiment, being arranged on different planes, the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341 are unlikely to contact each other. In a case of employing a configuration for countermeasures against heat by using the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341, the design constraints required for arranging these members in the same plane is relaxed. Therefore, when defining a path through which the air flowing around the exhaust conduit member is caused to flow, it is possible to widen the tolerance such as the dimensions and arrangements of the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341, which adds to the flexibility in design.
(6) In the turbine-side insulator 320, the first lower flange portion 331, the second lower flange portion 332, the third lower flange portion 333, the fourth lower flange portion 334, and the fifth lower flange portion 335 constitute a turbine-side lower flange portion 341B, which extends downward from the turbine-side body portion 340. This makes it difficult for air to flow not only in the inner peripheral region R of the exhaust conduit 60 but also in the region to the left of the inner peripheral region R that is arranged between the turbine housing 33 and the exhaust conduit 60. Therefore, by defining a flow path for the air flowing between the turbine housing 33 and the exhaust conduit 60 by the turbine-side insulator 320, it is possible to take countermeasures against heat for the devices arranged around the exhaust conduit member.
The above-illustrated embodiment may be modified as follows. The following modifications may be combined as necessary.
In the above-described embodiment, the turbine-side insulator 320 defines a flow path for the air flowing between the turbine housing 33 and the exhaust conduit 60. However, the manner of defining such a flow path can be changed as necessary. For example, at least one of the first lower flange portion 331, the second lower flange portion 332, the third lower flange portion 333, the fourth lower flange portion 334, and the fifth lower flange portion 335 may be omitted so that the shape of the turbine-side lower flange portion 341B in the turbine-side insulator 320 is changed. This allows for adjustment of the flow rate of the air flowing between the turbine housing 33 and the exhaust conduit 60. When the fifth lower flange portion 335 is omitted, the fourth lower flange portion 334 is extended rightward, for example. This achieves a configuration in which the turbine-side flange portion 341 is arranged in the inner peripheral region R of the exhaust conduit 60.
In the above-described embodiment, the turbine-side upper flange portion 341A is constituted by the first upper flange portion 326, the second upper flange portion 327, the third upper flange portion 328, the fourth upper flange portion 329, and the fifth upper flange portion 330. However, this configuration may be changed as necessary. For example, at least one of the first upper flange portion 326, the second upper flange portion 327, the third upper flange portion 328, the fourth upper flange portion 329, and the fifth upper flange portion 330 may be omitted. Further, the shape of the turbine-side upper flange portion 341A can be changed as necessary. For example, to facilitate the inflow of air guided to the space above the engine body 21 by the air guide plate 180 to between the turbine housing 33 and the turbine-side insulator 320, a turbine-side upper flange portion 341A may be extended upward beyond the upper end face of the engine body 21.
In the above-described embodiment, the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341 are arranged so as not to overlap with each other when viewed from the rear of the vehicle. The arrangement of the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341 is not limited thereto, and these members may be arranged so as to overlap with each other when viewed from the rear of the vehicle. For example, it is also possible to increase the length in the up-down direction at the left end of the inner flange portion 285 so that the left end of the inner flange portion 285 overlaps with the bracket 80. In addition, the inner flange portion 285 may be extended in the vehicle width direction so that the inner flange portion 285 overlaps with the bracket 80. It is also possible to arrange the inner flange portion 285 so as to overlap only with the turbine-side flange portion 341 without overlapping with the bracket 80.
Further, the bracket 80 may be arranged to overlap with at least one of the inner flange portion 285 and the turbine-side flange portion 341. In this case, it is also possible to cause the bracket 80 to overlap with at least one of the inner flange portion 285 and the turbine-side flange portion 341 by lengthening the bracket 80 in the left-right direction length or the up-down direction. Further, the turbine-side flange portion 341 may be arranged so as to overlap with at least one of the inner flange portion 285 and the bracket 80. In this case, it is also possible to cause the turbine-side flange portion 341 in the above embodiment to overlap with at least one of the inner flange portion 285 and the bracket 80 by changing the shape of the turbine-side flange portion 341 to extend rightward. The turbine-side flange portion 341 may overlap with only the inner flange portion 285 without overlapping with the bracket 80. Furthermore, the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341 may be arranged such that all of these overlap with one another when viewed from the rear of the vehicle.
In this way, when viewed from the rear of the vehicle, the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341 overlap with each other while being separated from each other in the longitudinal direction of the vehicle, so that a flow path is defined in which the air flowing in from the front of the vehicle is changed so as to flow in the vehicle width direction temporarily, and thereafter flows toward the rear of the vehicle. Therefore, air is unlikely to flow through the inner peripheral region R of the exhaust conduit 60, and the amount of air passing through the inner peripheral region R is further limited. Also, it is possible to cause the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341 to overlap with each other when viewed from the rear of the vehicle, while causing these to contact each other in the vehicle front-rear direction.
Other members may be arranged in the inner peripheral region R of the exhaust conduit 60 in addition to the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341. For example, a flange extending upward from the outer circumferential surface of the upper split part 301 of the downstream insulator 300 may be provided, and the flange may be arranged in the inner peripheral region R of the exhaust conduit 60.
The inner flange portion 285, the bracket 80, and the turbine-side flange portion 341 are arranged in different planes, but it is also possible to arrange at least two of these members in the same plane. The phrase “in the same plane” refers to a case in which at least a part of one member is arranged between the front end face and the rear end face of another member in the front-rear direction of the vehicle. For example, the inner flange portion 285 and the bracket 80 can be said to be “in the same plane” when, in the front-rear direction of the vehicle, the rear end face of the inner flange portion 285 is arranged between the front end face and the rear end face of the bracket 80, and the front end face of the inner flange portion 285 is arranged forward of the front end face of the bracket 80. The inner flange portion 285 may be arranged in the same plane as the turbine-side flange portion 341, the bracket 80 may be may be arranged in the same plane as the turbine-side flange portion 341, and the inner flange portion 285, the bracket 80, and the turbine-side flange portion 341 may be all arranged in the same plane.
The portion of the exhaust conduit 60 to which the bracket 80 is connected is not limited to the first catalyst support portion 75. For example, the bracket 80 may be connected to the first curved conduit 86 or the second curved conduit 88 of the curved shape portion 85. Alternatively, the bracket 80 may connected to the exhaust inflow portion 91 of the second catalyst support portion 90.
In the above-described embodiment, the turbine-side flange portion 341 in the turbine-side insulator 320 is arranged in the inner peripheral region R in the exhaust conduit 60. Instead of such a configuration, a configuration may be employed in which the turbine-side insulator 320 is omitted so that the turbine-side flange portion 341 is not arranged in the inner peripheral region R. This modification only requires that the shape of the inner flange portion 285 or the bracket 80, which are arranged in the inner peripheral region R, be appropriately determined from the viewpoint of countermeasures against heat of the devices arranged around the exhaust conduit member. For example, the left end of the bracket 80 may be extended leftward so that the bracket 80 is arranged below the sensor mount 65 of the exhaust conduit 60. It is also possible to extend the inner flange portion 285 leftward so that the inner flange portion 285 is arranged below the sensor mount 65 of the exhaust conduit 60.
In the above-described embodiment, the bracket 80, which is used to attach the exhaust conduit 60 to the engine body 21, is arranged in the inner peripheral region R of the exhaust conduit 60. Instead of such a configuration, it is also possible to employ a configuration in which the bracket 80 is not arranged in the inner peripheral region R. That is, the bracket 80 may be arranged in the outer peripheral region of the exhaust conduit 60. Alternatively, the bracket 80 may be omitted from the exhaust conduit 60. This modification only requires that the shapes of the inner flange portion 285 and the turbine-side flange portion 341, which are arranged in the inner peripheral region R, be appropriately determined from the viewpoint of countermeasures against heat of the devices arranged around the exhaust conduit member. For example, the length in the up-down direction at the left end of the inner flange portion 285 may be increased, so that the upper end of the left end is arranged at a position close to the first catalyst support portion 75. Also, the length in the vehicle width direction of the inner flange portion 285 may be increased, so that the left end of the inner flange portion 285 is arranged at a position close to the right end of the turbine-side flange portion 341. It is also possible to extend the turbine-side flange portion 341 rightward so that the turbine-side flange portion 341 is arranged below the first catalyst support portion 75.
In the above-described embodiment, the inner flange portion 285 of the exhaust conduit-side insulator 260 is provided continuously from the inside of the upstream flare portion 86A of the curved shape portion 85 to the inside of the lateral conduit portion 88C in the flow direction of exhaust gas, so that the right end of the inner peripheral region R of the exhaust conduit 60 is blocked. The shape of the inner flange portion 285 is not limited to this. For example, a configuration may be employed in which the inner flange portion 285 is provided to bridge, in the up-down direction, the inside of the upstream flare portion 86A of the curved shape portion 85 and the inside of the lateral conduit portion 88C, and the inner flange portion 285 is not provided in the inside from the first curved portion 86B to the second curved portion 88B in the flow direction of exhaust gas. In this configuration, an opening through which air can pass is provided in a part of the inner peripheral region R of the exhaust conduit 60 that is to the right of the portion in which the inner flange portion 285 is arranged.
In the above-described embodiment, the inner flange portion 285 is configured such that the proximal end (upper end) and the distal (lower end) in the extending direction (up-down direction) are connected to the curved-side body portion 280 in a portion arranged below the upstream flare portion 86A. The configuration of the inner flange portion 285 is not limited to this. For example, the inner flange portion 285 may have a configuration in which the distal end in the extending direction is not connected to the curved-side body portion 280 in a portion arranged below the upstream flare portion 86A. Also, the inner flange portion 285 may have a cutout.
In the above-described embodiment, the inner front flange 265 of the front split part 262 includes the inner front joint film portion 265A, and the inner rear flange 269 of the rear split part 266 includes the inner rear joint portions 269A. However, the inner front flange 265 may have the inner rear joint portions 269A, and the inner rear flange 269 may have the inner front joint film portion 265A.
In the above-described embodiment, the shape of the inner front joint film portion 265A of the inner front flange 265 and the shape of the inner rear joint portions 269A of the inner rear flange 269 are different from each other. Instead of such a configuration, the inner rear joint portions 269A and the inner front joint film portions 265A may have the same shape and be stacked and joined together to constitute the inner flange portion 285. Since the thickness of the inner flange portion 285 is increased as compared with the above embodiment, this modification is suitable for increasing the stiffness of the inner flange portion 285. In this configuration, in which the inner rear joint portions 269A and the inner front joint film portion 265A are stacked to increase the thickness of the inner flange portion 285, the thickness of only the inner flange portion 285 can be increased without changing the thickness of the curved-side body portion 280. Therefore, it is possible to increase the stiffness of the inner flange portion 285 while suppressing the increase in weight, as compared with a configuration in which the thickness of the entire upstream insulator 261 is increased to increase the thickness of the inner flange portion 285. In this way, from the viewpoint of increasing the stiffness of the inner flange portion 285, it is also possible to appropriately change the thickness of the inner front joint film portion 265A and the thickness of the inner rear joint portions 269A.
A protrusion may be provided on the front side surface of the inner flange portion 285. In this configuration, the protrusion increases the stiffness of the inner flange portion 285 and also adjusts the direction of air flow.
In the above-described embodiment, the exhaust conduit 60 is curved into a U-shape such that the flow of the exhaust gas flowing rightward in the vehicle width direction is directed downward and then leftward in the vehicle width direction. The shape of the exhaust conduit 60 is not limited to this. For example, the exhaust conduit 60 may be curved into a U-shape such that the flow of the exhaust gas flowing leftward in the vehicle width direction is directed downward and then rightward in the vehicle width direction. Further, the exhaust conduit 60 may have a curved shape other than a U-shape. In this case, for example, the exhaust conduit 60 may be curved into an L-shape such that the flow of exhaust gas flowing rightward in the vehicle width direction is directed rearward. In this case, if the extending length of the inner flange portion arranged in the inner peripheral region of the curved portion of the exhaust conduit having such an L shape is set to be longer than the extending length of the outer flange portion arranged in the outer peripheral region of the curved portion of the exhaust conduit, the air flowing about the exhaust conduit member is unlikely to flow to the inner peripheral region. The flow path of the air can be defined accordingly. However, if the space between the engine body 21 and the dashboard 210 is narrow in the engine compartment 10, the exhaust conduit is desirably curved into a U-shape in order to ensure a sufficient passage length of the exhaust passage.
Although the above-described embodiment provides a configuration in which the heat-resistant mat is sandwiched between the exhaust conduits 60 and the set of the upstream and the downstream insulators 261, 300, the heat-resistant mat is not necessarily required. That is, it is possible to omit the heat-resistant mat. If the heat-resistant mat is omitted, the upstream insulator 261 can be supported by exhaust conduit 60 in the following manner, for example. That is, a support portion for supporting the upstream insulator 261 on the exhaust conduit 60 is provided on the inner circumferential surface of the upstream insulator 261. By connecting this support portion to the outer circumferential surface of the exhaust conduit 60, the upstream insulator 261 is attached to the exhaust conduit 60 in a state separated from the exhaust conduit 60. This configuration is applicable to the downstream insulator 300.
In the upstream insulator 261 of the above-described embodiment, the outer front joint portions 264A and the outer rear joint portions 268A are joined together by crimping and welding, and the inner front joint film portions 265A and the inner rear joint portions 269A are joined together by crimping and welding. These joining methods can be changed as necessary. For example, these members may be joined together by welding only or by crimping only. It is also possible to construct the upstream insulator 261 by joining the above members using a joining method different from welding or crimping, such as adhesion. This configuration is applicable to the downstream insulator 300.
The upstream insulator 261 in the above-described embodiment is constituted by the two members, which are the front split part 262 and the rear split part 266. However, the upstream insulator 261 may be constituted by three or more members. This configuration also only requires that two or more flange portions, which include an inner flange portion and an outer flange portion, be used to join the multiple members, and that the extending length of the inner flange portion arranged in the inner peripheral region of the exhaust conduit be made longer than the extending length of the outer flange portion arranged in the outer peripheral region of the exhaust conduit.
The downstream insulator 300 in the above-described embodiment is constituted by the two members, which are the upper split part 301 and the lower split part 305. However, the downstream insulator 300 may be constituted by three or more members. This configuration also only requires that two or more flange portions, which include an inner flange portion and an outer flange portion, be used to join the multiple members, and that the extending length of the inner flange portion arranged in the inner peripheral region of the exhaust conduit be made longer than the extending length of the outer flange portion arranged in the outer peripheral region of the exhaust conduit.
In the exhaust conduit-side insulator 260 of the above-described embodiment, the upstream insulator 261 and the downstream insulator 300 are separately constructed. However, these can be constituted as a single member.
The shape of each of the first fixing lug 93, the second fixing lug 97, and the third fixing lug 105 can be changed as necessary. For example, the second front wall portion 101 of the second fixing lug 97 may be omitted so that the second fixing lug 97 has an opening facing forward.
The position and shape of the rib 314, which is provided in the downstream insulator 300 in the above-described embodiment, may be changed as necessary. For example, two or more ribs may be provided in the downstream insulator 300. In order to increase the stiffness, the upstream insulator 261 or the turbine-side insulator 320 may have a rib as necessary.
In the above-described embodiment, the downstream insulator 300 has the recess the recess 315, so that the turbine-side flange portion 341 and the downstream insulator 300 are prevented from contacting each other while arranging the turbine-side flange portion 341 of the turbine-side insulator 320 at a position close to the downstream insulator 300. The recess 315 does not necessarily have to be provided. It is also possible to determine the size and shape of the turbine-side flange portion 341 such that the turbine-side flange portion 341 contacts the downstream insulator 300.
The number of catalysts accommodated in the exhaust conduit 60 and the number of attached sensors can be changed as necessary. Also, the accommodation position of the catalyst and the attachment position of the sensor can be changed. For example, a catalyst may be accommodated in the curved shape portion 85. For early warm-up of the catalyst, it is desirable to place the catalyst on the upstream side in the flow of exhaust gas.
The shape of the turbine housing 33 is not limited to that of the above-described embodiment but may be changed as necessary.
In the above-described embodiment, the forced-induction device 30 is provided in the internal combustion engine 20. However, the forced-induction device 30 is not necessarily required. That is, the upstream end of the exhaust conduit 60 may be connected to the engine main body without the turbine housing 33 in between.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-201137 | Oct 2017 | JP | national |
