Heat shielding structure for vehicle

Abstract

To protect a protection target mounted on a vehicle from radiation heat.SOLUTION: A heat shielding structure for a vehicle includes: catalysts 6, 7 disposed on the lateral side of an internal combustion engine body 3; a drive shaft 11 disposed below the catalysts 6, 7; a drive shaft boot 12 that covers a part of the drive shaft 11; a support member 14 that supports a downstream side catalyst 7; a drive shaft heat shielding plate 13 located between the catalysts 6, 7 and the drive shaft 11; and a wind shielding plate 15 located between the internal combustion engine body 3 and the downstream side catalyst 7 and fixed to the support member 14. The support member 14 and the wind shielding plate 15 are disposed so that positions thereof in a drive shaft axial direction are overlapped with the drive shaft boot 12. The wind shielding plate 15 is formed to close a gap between the internal combustion engine body 3 and the drive shaft heat shielding plate 13.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat insulating structure for a vehicle equipped with an internal combustion engine. [Background technology]

[0002] For example, Patent Document 1 discloses a vibration-damping bushing having a cylindrical outer tube member, a cylindrical inner tube member arranged on the inner periphery of the outer tube member, and an elastic rubber having one end vulcanization-bonded to the inner periphery of the outer tube member and the other end vulcanization-bonded to the outer periphery of the inner tube member.

[0003] The vibration-isolating bushing of Patent Document 1 has a heat shield plate integrally formed on the outer cylindrical member to protect the elastic rubber from radiant heat from the heat source. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2-118224 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there are cases where a heat shield cannot be integrally formed with a component that needs to be protected from radiant heat. For example, if the component that needs to be protected from radiant heat is a non-stationary object that moves, such as by rotation or translation, if a heat shield is integrally formed with the non-stationary component that needs to be protected, the heat shield will move together with the component to be protected, and there is a risk of problems due to the integral formation of the heat shield, such as interference with surrounding components.

[0006] That is, when the object to be protected from radiant heat is a moving object, there is room for further improvement in protecting the object from radiant heat. [Means for solving the problem]

[0007] The heat shield structure for a vehicle of the present invention includes an exhaust gas purification catalyst arranged on a side of an internal combustion engine body, a drive shaft arranged on the side of the internal combustion engine body and below the catalyst, a drive shaft boot covering a portion of the drive shaft, a support member supporting the catalyst on the internal combustion engine body, a heat shield plate located between the catalyst and the drive shaft and fixed to the internal combustion engine body, and a wind shield plate located between the internal combustion engine body and the catalyst and fixed to the support member. The support member and the wind shield plate are arranged so as to overlap with the drive shaft boot in the axial direction of the drive shaft. The wind shield plate is formed to close the gap between the internal combustion engine body and the heat shield plate. [Effects of the Invention]

[0008] According to the present invention, the flow of air from the catalyst side toward the drive shaft boot through the gap between the internal combustion engine body and the heat shield is suppressed, thereby suppressing the thermal impact on the drive shaft and drive shaft boot, which are the objects to be protected from radiant heat from the catalyst side. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram showing a schematic overview of a heat shield structure for a vehicle equipped with an internal combustion engine, as viewed from the side of the vehicle; [Figure 2] 1 is an explanatory diagram showing a schematic outline of a heat shield structure for a vehicle equipped with an internal combustion engine, as viewed from the front of the vehicle; DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will be described in detail below with reference to the drawings.

[0011] Figures 1 and 2 are explanatory diagrams that schematically show an outline of a heat insulating structure for a vehicle to which the present invention is applied. Figure 1 is an explanatory diagram that schematically shows an outline of the heat insulating structure for a vehicle equipped with an internal combustion engine when viewed from the side of the vehicle. Figure 2 is an explanatory diagram that schematically shows an outline of the heat insulating structure for a vehicle equipped with an internal combustion engine when viewed from the front of the vehicle. In Figure 1, the left side in the left-right direction is the front side of the vehicle, and the internal combustion engine is placed transversely relative to the vehicle.

[0012] The internal combustion engine of the embodiment is, for example, an in-line multi-cylinder internal combustion engine, and an internal combustion engine body 3 is formed by a metal cylinder block 1 and a metal cylinder head 2. In practice, the internal combustion engine of the embodiment has an oil pan (not shown) attached to the underside of the cylinder block 1.

[0013] An exhaust system component 5 such as an exhaust manifold that constitutes part of an exhaust passage 4 is connected to the cylinder head 2. An upstream catalyst 6 and a downstream catalyst 7 for purifying exhaust gas are arranged in series in the exhaust passage 4 downstream of the exhaust system component 5 (downstream in the exhaust flow direction).

[0014] More specifically, the upstream catalyst 6 and the downstream catalyst 7 are connected so as to form an overall L-shape when viewed from the side of the internal combustion engine body 3, as shown in FIG. 2 . That is, the exhaust passage 4 is bent 90 degrees at the portion consisting of the upstream catalyst 6 and the downstream catalyst 7, forming an L-shape. In other words, the exhaust passage 4 has, on the side (exhaust side) of the internal combustion engine body 3, a vertical side 8 extending along the vehicle vertical direction, which is the vertical direction in FIG. 2 , and a horizontal side 9 extending along the cylinder row direction of the internal combustion engine, which is the left-right direction in FIG. 2 (the crankshaft axial direction of the internal combustion engine). The vertical side 8 is mainly composed of the upstream catalyst 6. The horizontal side 9 is mainly composed of the downstream catalyst 7 and a portion of the exhaust passage 4 continuing downstream from the downstream catalyst 7. Note that in this specification, the vertical direction of the vehicle is synonymous with the cylinder axial direction, which is the axial direction of the cylinders of the internal combustion engine.

[0015] The upstream catalyst 6 and the downstream catalyst 7 are located on the sides of the internal combustion engine body 3 and are spaced apart from the side surfaces of the internal combustion engine body 3 by a predetermined distance.

[0016] The outer surfaces (outer periphery of the casing) of the upstream catalyst 6 and the downstream catalyst 7 are covered with a heat insulating cover 10. The heat insulating cover 10 suppresses heat transfer from the catalysts 6, 7, which are heat sources, to the outside.

[0017] The upstream catalyst 6 is made of, for example, a three-way catalyst, and is arranged upstream (upstream in the exhaust flow direction) of the downstream catalyst 7. The downstream catalyst 7 is, for example, a combination of a three-way catalyst and a GPF (Gasoline Particulate Filter), and has an internal structure in which the GPF is arranged in series downstream of the three-way catalyst.

[0018] A three-way catalyst purifies the three components of HC, CO, and NOx in the inflowing exhaust gas when the excess air ratio is approximately 1, that is, when the exhaust air-fuel ratio is approximately the stoichiometric air-fuel ratio. A GPF captures PM, which is particulate matter in the exhaust gas, and can then combust the captured PM (GPF regeneration process).

[0019] The vehicle has a metal drive shaft 11, a rubber or resin drive shaft boot 12 that covers a section of the drive shaft 11, a drive shaft heat shield 13 that suppresses the thermal effect from catalysts 6 and 7 on the drive shaft 11, a support member 14 that supports the downstream catalyst 7 on the cylinder block 1, and a wind shield 15 fixed to the support member 14.

[0020] The drive shaft 11 transmits the rotation of the crankshaft (not shown) of the internal combustion engine to drive wheels (not shown), and is disposed on the side of the internal combustion engine body 3. The drive shaft 11 is disposed at a predetermined distance from the side of the internal combustion engine body 3. The drive shaft 11 is disposed at a height position where it overlaps with the cylinder block 1 in the vertical direction of the vehicle, and is disposed below the upstream catalyst 6 and downstream catalyst 7 and spaced apart from these catalysts 6, 7 in the vertical direction of the vehicle.

[0021] The drive shaft 11 has a first shaft 11a and a second shaft 11b connected via a joint 11c in a portion located below the downstream catalyst 7. The drive shaft 11 has a section (predetermined section) located below the downstream catalyst 7 that is defined by the joint 11c.

[0022] The drive shaft boot 12 is a cylindrical member made of, for example, rubber or resin, and covers the entire circumference of the joint 11c of the drive shaft 11. In other words, the drive shaft boot 12 covers the entire circumference of a predetermined section of the drive shaft 11 that is located below the downstream catalyst 7.

[0023] The drive shaft heat shield 13 corresponds to a heat shield, and is disposed between the drive shaft 11 and the catalysts 6, 7 in the vertical direction of the vehicle. More specifically, the drive shaft heat shield 13 is set to a length that can cover the portion of the exhaust passage 4 that is close to the drive shaft 11 and the drive shaft boot 12 in the cylinder row direction of the internal combustion engine (for example, the vertical side portion 8 and the horizontal side portion 9).

[0024] The drive shaft heat shield 13 is formed by bending a member made of a metal material such as iron by press working, etc. The drive shaft heat shield 13 has a generally arc-shaped cross section extending along the cylinder row direction of the internal combustion engine, and is positioned so that the inside of the arc faces the upper portions of the outer surfaces of the drive shaft 11 and drive shaft boot 12 at a predetermined distance.

[0025] The drive shaft heat shield 13 has a one-end fixing point 16 located at one end in the direction of cylinder alignment of the internal combustion engine, fixed to a side surface of the cylinder block 1 of the internal combustion engine body 3. The drive shaft heat shield 13 has a other-end fixing portion (not shown) located at the other end in the direction of cylinder alignment of the internal combustion engine, which is fixed to, for example, a structure (such as a transmission housing) arranged adjacent to the internal combustion engine. The drive shaft heat shield 13 may be configured so that the other-end fixing point is fixed to the cylinder block 1. The drive shaft heat shield 13 is a double-supported component whose both end portions are fixed to the cylinder block or the like in the direction of cylinder alignment of the internal combustion engine.

[0026] In addition, the drive shaft heat shield 13 is formed so that the portions other than the fixed points, such as the fixed point on one end side, in the drive shaft axial direction (direction of the cylinder row of the internal combustion engine), which is perpendicular to the plane of the paper in Figure 1, are separated from the side of the cylinder block 1 of the internal combustion engine main body 3. Furthermore, the drive shaft heat shield 13 is formed so that the portions other than the fixed points such as the fixed point on the one end side in the drive shaft axial direction (direction of the cylinder row of the internal combustion engine), which is perpendicular to the plane of the paper in Figure 1, have a predetermined gap 17 between them and the side of the cylinder block 1 of the internal combustion engine main body 3.

[0027] The support member 14 is formed by bending a metal material such as stainless steel by press working or the like, and is fixed to the side of the internal combustion engine body 3. The support member 14 has a first fixing portion 18 fixed to the cylinder block 1 of the internal combustion engine body 3, a second fixing portion 19 fixed to the downstream catalyst 7, and a main body portion 20 located between the first fixing portion 18 and the second fixing portion 19 to connect them.

[0028] The first fixing portion 18 has, for example, a rectangular plate shape and is fixed to a boss portion 22 of the cylinder block 1 by a bolt 21. The boss portion 22 is, for example, a portion with a circular cross section that protrudes from the cylinder block 1 and is relatively thick. The front surface of the first fixing portion 18 faces the gap between the downstream catalyst 7 and the drive shaft 11, and the back surface faces the tip of the boss portion 22 or the side surface of the cylinder block 1 that forms the side surface of the internal combustion engine main body 3. The first fixing portion 18 is bent at a predetermined angle in the left-right direction of FIG. 1 (the front-rear direction of the vehicle) with respect to the main body portion 20.

[0029] The second fixing portion 19 has a fixing piece 19a that is fixed to the outer peripheral surface of the downstream catalyst 7, for example, by welding, and a connecting piece 19b that is bent from the fixing piece 19a and continues to the main body portion 20, and has a generally L-shape as a whole. The fixing piece 19a and the connecting piece 19b each have, for example, a rectangular plate shape. The heat insulating cover 10 has a fixing hole 10a formed by cutting out a portion of the outer peripheral surface of the downstream catalyst 7 where the fixing piece 19a is to be fixed, so that the fixing piece 19a can be directly fixed to the outer peripheral surface of the downstream catalyst 7. The fixing hole 10a is, for example, a hole with a rectangular outline.

[0030] The fixing piece 19a of the second fixing part 19 has a front surface facing the outer peripheral surface of the downstream catalyst 7 and a back surface facing the side surface of the cylinder block 1 that constitutes the side surface of the internal combustion engine body 3. The connecting piece 19b of the second fixing part 19 is arranged so that the front and back surfaces are perpendicular to the crankshaft of the internal combustion engine body 3. In other words, the fixing piece 19a of the second fixing part 19 is bent from the connecting piece 19b so as to be approximately parallel to the main body part 20. The connecting piece 19b of the second fixing part 19 is bent from the main body part 20 so as to be perpendicular to the main body part 20.

[0031] The main body 20 has, for example, a rectangular plate shape and is continuous with the connecting pieces 19b of the first fixed part 18 and the second fixed part 19 while being inclined at a predetermined angle to each other. The main body 20 is located between the downstream catalyst 7 and the cylinder block 1, with its front surface facing the downstream catalyst 7 and its back surface facing the side surface of the cylinder block 1 that constitutes the side surface of the internal combustion engine body 3.

[0032] The windshield 15 is formed by bending a member made of a metal material such as stainless steel by press working or the like, and is fixed to the support member 14. The windshield 15 has a central portion 15a fixed to the support member 14, and upper and lower end portions 15b and 15c connected above and below the central portion 15a.

[0033] The central portion 15a has, for example, a rectangular plate shape, overlaps the main body portion 20 of the support member 14, and is fixed to the main body portion 20 of the support member 14.

[0034] The upper end portion 15b has, for example, a rectangular plate shape and is continuous with the upper end of the central portion 15a in the vehicle vertical direction. The upper end portion 15b extends a predetermined length upward from the central portion 15a so that high-temperature air heated by the exhaust system components 5, the exhaust passage 4, the internal combustion engine body 3, the downstream catalyst 7, etc. is less likely to pass between the support member 14 and the cylinder block 1 of the internal combustion engine body 3 and flow into the drive shaft boot 12. In other words, the upper end portion 15b extends a predetermined length upward from the central portion 15a so that the distance D between the tip of the upper end portion 15b and the cylinder block 1 is reduced. In other words, the upper end portion 15b is configured to block the flow of air passing between the support member 14 and the internal combustion engine body 3 and flowing into the drive shaft boot 12.

[0035] In other words, the windshield 15 is formed to have an upper end 15b that is located closer to the cylinder head of the internal combustion engine body 3 than the support member 14, so as to block the flow of wind that passes between the support member 14 and the internal combustion engine body 3 and turns around to the drive shaft boot 12.

[0036] The lower end portion 15c has, for example, a rectangular plate shape, and is continuous with the lower end of the central portion 15a in the vehicle up-down direction.

[0037] The lower end portion 15c is formed to close the gap 17 between the cylinder block 1 of the internal combustion engine body 3 and the drive shaft heat shield 13, and extends downward from the central portion 15a. More specifically, the lower end portion 15c is bent with respect to the central portion 15a so as to overlap the end portion of the drive shaft heat shield 13 on the internal combustion engine body side in the left-right direction in FIG. 1 (the vehicle front-rear direction), and is set to extend downward from the central portion 15a as a whole.

[0038] The heat shielding structure of the vehicle in the above-described embodiment is formed so that the windshield 15 blocks the portion of the gap 17 along the drive shaft axial direction that occurs between the internal combustion engine body 3 and the drive shaft heat shield 13, which overlaps with the position where the drive shaft boot 12 is positioned in the drive shaft axial direction.

[0039] Therefore, the vehicle can suppress the flow of air passing through the gap 17 between the internal combustion engine body 3 and the drive shaft heat shield plate 13 from the downstream catalyst 7 side toward the drive shaft boot 12 side.

[0040] In particular, air that may be significantly affected by heat from the downstream catalyst 7 and become hot as it passes through the front surface of the fixing hole 10a of the heat shield cover 10 can be prevented from passing through the gap 17 between the internal combustion engine body 3 and the drive shaft heat shield plate 13 and reaching the drive shaft boot 12 side.

[0041] This makes it possible to suppress the thermal influence on the drive shaft 11 and the drive shaft boot 12, which are objects to be protected from the radiant heat from the downstream catalyst 7 side.

[0042] The upper end 15b of the windshield 15 is set so as to block the flow of air that passes between the support member 14 and the internal combustion engine body 3 and turns around to the drive shaft boot 12. Therefore, at the position where the windshield 15 is arranged, the amount of air flowing between the windshield 15 and the downstream catalyst 7 (thick arrow in FIG. 1) is greater than the amount of air flowing between the windshield 15 and the internal combustion engine body 3 (thin arrow in FIG. 1).

[0043] As a result, the vehicle can promote the introduction of air between the downstream catalyst 7 and the drive shaft heat shield 13 through the action of the windshield 15, reducing heat stagnation between the downstream catalyst 7 and the drive shaft heat shield 13 and improving the heat shielding effect on the drive shaft 11 and drive shaft boot 12.

[0044] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention. [Explanation of symbols]

[0045] 1...Cylinder block 2...Cylinder head 3...Internal combustion engine body 4...Exhaust passage 6...Upstream catalyst 7...Downstream catalyst 10...Heat-shielding cover 10a…Fixing hole 11...Drive shaft 12...Drive shaft boot 13...Drive shaft heat shield 14...Support member 15...Wind shielding board 15a...Central part 15b...Top end 15c…lower end 17...Gap 18...First fixed part 19…Second fixed part 20...Main body

Claims

1. an exhaust gas purification catalyst disposed on a side of the internal combustion engine body; a drive shaft disposed on a side of the internal combustion engine body and below the catalyst; a drive shaft boot covering a portion of the drive shaft; a support member that supports the catalyst on the internal combustion engine body; a heat shield plate located between the catalyst and the drive shaft and fixed to the internal combustion engine body; a windshield located between the internal combustion engine body and the catalyst and fixed to the support member, the support member and the windshield are arranged so as to overlap with the drive shaft boot in the axial direction of the drive shaft, The heat shielding structure for a vehicle is characterized in that the windshield is formed so as to close a gap between the internal combustion engine body and the heat shield.

2. The heat-shielding structure for a vehicle as described in claim 1, characterized in that the windshield is formed to have a portion located closer to the cylinder head of the internal combustion engine body than the support member so as to block the flow of wind passing between the support member and the internal combustion engine body and circulating around the drive shaft boot.

3. the support member has a first fixing portion fixed to the internal combustion engine body, a second fixing portion fixed to the catalyst, and a main body portion located between the first fixing portion and the second fixing portion and connecting them together, The windshield plate has a central portion fixed to the main body portion of the support member and overlapping with the main body portion, an upper end portion connected to an upper end of the central portion and extending upwardly, and a lower end portion connected to a lower end of the central portion and closing a gap between the internal combustion engine main body and the heat shield plate, 2. The heat insulating structure for a vehicle according to claim 1, wherein the lower end portion is set to overlap the heat insulating plate.

4. The heat-shielding structure for a vehicle as described in claim 3, characterized in that the upper end of the windshield is configured to block the flow of wind passing between the support member and the internal combustion engine body and circulating around the drive shaft boot.

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