JP3874232B2 - Engine exhaust system support structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine exhaust system support structure. In particular, the stiffener can absorb the extension of the catalyst portion in the axial direction due to the thermal expansion of the exhaust manifold and the like, and can be tightened in one direction. The present invention relates to an exhaust system support structure for an engine that can be machined and can reduce the distance by which an operator moves a tool, thereby improving the assembly.
[0002]
[Prior art]
The engine includes a cylinder block, a cylinder head mounted on the upper surface of the cylinder block, and an oil pan mounted on the lower surface of the cylinder block. The cylinder head is provided with an intake manifold and an exhaust manifold, and an intake system and an exhaust system communicating with the combustion chamber of the engine are configured.
[0003]
An exhaust system support structure for the engine is disclosed in Japanese Patent Publication No. 6-102971. The exhaust system mounting apparatus in a vehicle disclosed in this publication is an exhaust system mounting structure in a vehicle in which an engine is mounted horizontally so that a plurality of exhaust ports are fluttered, and a plurality of pipes connected to the exhaust ports. An exhaust manifold with a catalytic converter is constructed by welding a branch pipe made of a material to the collective case containing the exhaust catalyst, and the exhaust pipe connected to the collective case is extended from the front of the engine to the rear through the lower side. The first stay is disposed between the front upper portion of the cylinder block of the engine and the engine facing surface of the collective case, and the collective case is connected and supported to the cylinder block by the first stay, and the exhaust pipe is connected to the back of the engine. It is supported by a second stay attached to the lower part.
[0004]
Further, there is one disclosed in JP-A-6-101462. An exhaust device for an internal combustion engine for a vehicle disclosed in this publication is a horizontal type exhaust gas pipe disposed on the output shaft side of an internal combustion engine for a vehicle having an output shaft parallel to a crankshaft, and an intermediate portion of the exhaust pipe. In the exhaust device provided with the catalyst, the catalyst is arranged above the output shaft and the flow direction of the exhaust gas passing through the catalyst is substantially parallel to the output shaft, and the weight of the support stay is increased. A reduction in engine room space efficiency is avoided.
[0005]
Further, there is one disclosed in JP-A-8-193514. The vehicle exhaust pipe connection structure disclosed in this publication is provided with an exhaust manifold connected to the exhaust side of an engine in a vehicle exhaust pipe that exhausts exhaust gas from an engine mounted on the vehicle to the outside through a catalyst. An exhaust pipe connected downstream of the exhaust manifold, a joint between the exhaust pipe and the catalyst, an engine mounted on a center member extending in the front-rear direction of the vehicle via a rear mount and a mound bracket, An exhaust pipe stiffener connected to the mount bracket is provided at a position upstream of the joint portion, facilitating assembly in the line, reducing the assembly time, and reducing the assembly failure.
[0006]
There is one disclosed in JP-A-11-159326. The exhaust system structure of the internal combustion engine disclosed in this publication is the exhaust system structure of the internal combustion engine, one of which is fixed to the clutch housing of the internal combustion engine and the other is fixed to any one of the first and second catalysts. While providing a stiffener, the stiffener is fixed to the clutch housing side, a second fixing portion for fixing any one of the catalysts, and a stiffener positioned between the first and second fixing portions. It has the structure which has the convex part which protrudes to an outer side, makes a convex part function as a heat insulation wall, and prevents that a harness is exposed to the high temperature from a catalyst.
[0007]
There is one disclosed in JP-A-11-229863. The engine exhaust system supporting structure disclosed in this publication is such that an exhaust manifold branch pipe is connected to an exhaust port of the engine body, a catalytic converter is connected to an assembly portion of the exhaust manifold, and an exhaust pipe is further connected to the catalytic converter. Then, both ends of the support member are connected to the bracket of the exhaust manifold and the bracket of the engine body so as to be rotatable by bolts to form a link mechanism, and the vibration of the catalytic converter is suppressed by the exhaust manifold and the support member, By forming a link mechanism with the support member and allowing the axial movement of the catalytic converter, the thermal expansion difference between the exhaust manifold and the catalytic converter and the engine body is absorbed, and damage due to thermal stress is prevented.
[0008]
There is one disclosed in Japanese Utility Model Publication No. 7-5224. The balancer shaft overheat prevention device for an internal combustion engine disclosed in this publication is arranged so that the balancer shaft extending parallel to the crankshaft is close to the outer surface of one side of the cylinder block along the direction orthogonal to the axis of the crankshaft. In an internal combustion engine that is rotatably supported and in which an exhaust manifold is disposed at an outer position close to the outer surface, a heat shield is disposed between the outer surface of the cylinder block and the exhaust manifold, and from the exhaust manifold. The adverse effect of heat radiation is prevented from reaching the balancer shaft, ensuring smooth rotation of the balancer shaft.
[0009]
[Problems to be solved by the invention]
In the conventional engine exhaust system support structure, the stiffener 124 for fixing the exhaust manifold 114 to a cylinder block (not shown) is fastened to the cylinder block and the exhaust manifold 114 by a plurality of tightening bolts 140 as shown in FIG. Yes.
[0010]
However, as is apparent from FIG. 9, the tightening direction of the tightening bolt 140 is two or more, and there is an inconvenience that the amount of tool movement by the operator is large, which is disadvantageous in practice.
[0011]
When the stiffener is fastened to the cylinder block, it is necessary to process the block side stiffener boss in the cylinder block, which increases the number of processing steps, increases the cost, and is disadvantageous economically. is there.
[0012]
Further, depending on the type of vehicle, the stiffener shape may be complicated. For example, as shown in FIG. 10, there is a two-piece structure including first and second stiffeners 224-1 and 224-2.
[0013]
However, with this two-piece structure, it is difficult to achieve a shape that takes into account both the stiffener effect and the absorption of the thermal expansion of the exhaust manifold, and the manufacturing cost of the stiffener is increased, which is economically disadvantageous. There is an inconvenience.
[0014]
[Means for Solving the Problems]
Accordingly, the present invention is to eliminate the above disadvantages, and a collection portion to assemble the downstream side of the branch pipe portion and these branch pipe portion in the exhaust manifold of an engine mounted on the cylinder head is provided, of the exhaust manifold the catalyst portion is provided directly under the collecting part, the catalyst unit in the exhaust system support structure being fixed to the engine via a stiffener formed by a plate-like member while being disposed on the side of the cylinder block, the engine to the stiffener and a connection step portion to contact the side mounting surface and catalyst-side mounting surface and these provided the same direction by the position so as to intersect perpendicularly and the engine side mounting surface and the catalyst mounting surface with respect to the axial direction of the catalyst unit thereby forming was directed bending between the engine side mounting surface and the catalyst mounting surface to form the connection step portion in the cylinder of the engine side mounting surface It is attached to the lower surface of the lock and the catalyst side mounting surface is attached to the exhaust pipe mounting flange of the catalyst unit, the lower surface of the cylinder block and the mounting direction to the exhaust side pipe mounting flange are matched, and the lower surface of the cylinder block and the exhaust side pipe The mounting height positions of the mounting flanges are different from each other, and the connection stepped portions are formed in a crank shape corresponding to the difference in the mounting height positions of the stiffeners. A bent portion and an extending portion extending in the axial direction of the catalyst portion are provided .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
As a result of the invention as described above, when the exhaust manifold is attached to the cylinder block of the engine with a stiffener, the engine-side mounting surface and the catalyst-side mounting surface of the stiffener are made perpendicular to the axial direction of the catalyst portion. Absorbed by a stiffener with a simple configuration, the catalyst portion is extended in the axial direction due to thermal expansion of the exhaust manifold, etc., and the engine side mounting surface and the catalyst side mounting surface of the stiffener are in the same direction. As a result, the tightening direction is set to one direction, the simultaneous machining is possible, the distance that the operator moves the tool is reduced, and the assembling property is improved.
[0016]
【Example】
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0017]
1 to 6 show an embodiment of the present invention. In FIG. 1, 2 is an engine.
[0018]
The engine 2 includes a cylinder block 4, a cylinder head 6 placed on the upper surface 4 a of the cylinder block 4, a cylinder head cover 8 placed on the upper surface 6 a of the cylinder head 6, and a lower surface 4 b of the cylinder block 4. And an oil pan 10 to be mounted.
[0019]
A crankshaft 12 extending in the longitudinal direction of the engine 2 is disposed below the cylinder block 4.
[0020]
The cylinder head 6 is provided with an intake manifold and an exhaust manifold 14 (not shown), and an intake system and an exhaust system that communicate with a combustion chamber (not shown) of the engine 2 are configured.
[0021]
As shown in FIG. 5, the exhaust manifold 14 includes a cylinder head mounting flange 16 provided on the upstream side, a plurality of branch pipe portions 18 connected to the cylinder head mounting flange 16 on one upstream side, and these And a collecting portion 20 for collecting the downstream side which is the other end of the branch pipe portion 18.
[0022]
And the catalyst part 22 is provided in the downstream of this gathering part 20. FIG. As shown in FIG. 1, the catalyst portion 22 is disposed on the side of the cylinder block 4 and is fixed to the engine 2 via a stiffener 24.
[0023]
At this time, the stiffener 24 is bent by a plate-like member, and an engine-side mounting surface 26 and a catalyst-side mounting surface 28 are provided, and the engine-side mounting surface 26 and the catalyst-side mounting surface 28 are connected to the catalyst portion 22. It is configured to be positioned substantially parallel to a plane perpendicular to the axial direction and to be directed in the same direction.
[0024]
More specifically, as shown in FIGS. 2 and 3, the stiffener 24 is bent by a plate-like member to form two engine side mounting surfaces 26 and catalyst side mounting surfaces 28 having different mounting height positions. . The connecting step portion 30 that connects the engine-side mounting surface 26 and the catalyst-side mounting surface 28 is arbitrarily set in the step amount, the connecting distance, or the directing direction depending on the mounting state of the catalyst portion 22 to the cylinder block 4. It is what is done.
[0025]
The oil pan mounting surface 32 for the oil pan 10 formed on the lower surface 4b of the cylinder block 4 is for tightening the stiffener at a position on the same plane as the oil pan mounting surface 32 and close to the oil pan 10. An internal thread 34 is provided, and the engine side mounting surface 26 of the stiffener 24 is mounted on the lower surface 4 b of the cylinder block 4 using the internal thread 34 for tightening the stiffener.
[0026]
Further, the catalyst side mounting surface 28 of the stiffener 24 is mounted on an exhaust pipe mounting flange 36 for connecting the catalyst portion 22 and an exhaust pipe (not shown) as shown in FIG.
[0027]
The stiffener 24 has a projection 38 for preventing erroneous assembly at the end of the catalyst side mounting surface 28 located on the opposite side to the engine side mounting surface 26.
[0028]
Reference numeral 40 denotes a tightening bolt used for the stiffener 24, 42 denotes a first attachment hole formed in the engine-side attachment surface 26 of the stiffener 24, and 44 denotes a catalyst-side attachment surface 28 of the stiffener 24. A second mounting hole 46 is a stiffener mounting hole formed on the lower surface of the cylinder block 4, and a mounting surface 48 is formed on the cylinder block 4 such as a transmission case.
[0029]
Here, when the exhaust pipe mounting flange 36 is additionally described, the exhaust pipe mounting flange 36 has, for example, two exhaust pipe mounting first and second mounting portions projecting in the manifold row direction as shown in FIG. 2 holes 36-1 and 36-2 are provided, and between these first and second holes 36-1 and 36-2 is extended in the manifold row direction to provide a substantially triangular extension 51, and this extension A stiffener mounting hole 36-3 is provided in the portion 51.
[0030]
Next, the operation will be described.
[0031]
When the exhaust manifold 14 is attached to the cylinder block 4 of the engine 2 by the stiffener 24, the exhaust manifold 14 is provided on the same surface as the oil pan mounting surface 32 of the lower surface 4b of the cylinder block 4 and in a position close to the oil pan 10. As shown in FIG. 1, the engine side mounting surface 26 of the stiffener 24 is attached to the lower portion of the cylinder block 4 with a fastening bolt 40 using the stiffener fastening female screw 34.
[0032]
Further, the catalyst side attachment surface 28 of the stiffener 24 is attached to an exhaust pipe attachment flange 36 that connects the catalyst portion 22 and an exhaust pipe (not shown) with a fastening bolt 40.
[0033]
At this time, when the engine side attachment surface 26 of the stiffener 24 is attached to the lower portion of the cylinder block 4, if the catalyst side attachment surface 28 is mistakenly attached to the lower portion of the cylinder block 4, as shown in FIG. A protrusion 38 formed on the end of the catalyst side mounting surface 28 of the 24 contacts the oil pan 10 and is formed on the catalyst side mounting surface 28 of the stiffener 24 in a stiffener mounting hole 46 formed on the lower surface of the cylinder block 4. The second mounting hole 44 does not match and cannot be mounted, thereby preventing erroneous assembly.
[0034]
As a result, the engine-side mounting surface 26 and the catalyst-side mounting surface 28 of the stiffener 24 are positioned substantially parallel to the plane perpendicular to the axial direction of the catalyst portion 22, and the catalyst due to thermal expansion of the exhaust manifold 14 or the like. The axial extension of the portion 22 can be absorbed by the stiffener 24 having a simple configuration, which is practically advantageous.
[0035]
In addition, since the engine side mounting surface 26 and the catalyst side mounting surface 28 of the stiffener 24 are oriented in the same direction, the tightening direction of the tightening bolt 40 can be set to one direction, and simultaneous processing is possible. Thus, the distance that the operator moves the tool can be reduced, and the assemblability can be improved.
[0036]
Furthermore, since both ends of the stiffener 24 can be attached to the lower portion of the cylinder block 4 adjacent to the oil pan 10 and the exhaust pipe mounting flange 36, it is not necessary to newly provide a bracket on the engine body or the catalyst portion 22. There is no possibility of increasing the number of parts, the cost can be kept low, and the dead space on the side of the oil pan 10 can be used effectively, which is practically advantageous.
[0037]
Furthermore, the stiffener 24 is provided with a projection 38 for preventing erroneous assembly at the end of the catalyst-side mounting surface 28 located on the opposite side of the engine-side mounting surface 26. Further, the projection 38 comes into contact with the oil pan 10 and cannot be attached, so that erroneous assembly can be reliably prevented.
[0038]
Further, the stiffener 24 is bent so as to have flexibility with respect to the thermal expansion of the exhaust manifold 14 (Z-axis direction in FIG. 5), and also in the front-rear and left-right directions (X-axis and Y-axis directions in FIG. 5). ) And a high stiffener effect.
[0039]
Further, by providing the stiffener tightening female screw 34 on the same surface with respect to the oil pan mounting surface 32, the stiffener tightening female screw 34 can be processed when the oil pan mounting female screw is processed. The stiffener fastening female thread 34 can be easily formed, which is practically advantageous.
[0040]
The present invention is not limited to the above-described embodiments, and various application modifications are possible.
[0041]
For example, in the embodiment of the present invention, the stiffener is formed by a plate-like member. However, when the stiffener 52 is formed, a special configuration in which the reinforcing bead portion 54 is formed at the outer peripheral portion can be used. is there.
[0042]
That is, as shown in FIGS. 7 and 8, the convex reinforcing bead portion 54 is formed on the outer peripheral portion of the stiffener 52.
[0043]
Then, even if the stiffener 52 is formed by a plate-like member, sufficient rigidity can be ensured by the reinforcing bead 54, and the elastic range of the stiffener 52 in the axial direction of the catalyst portion can be expanded. This is advantageous.
[0044]
In addition, when forming the stiffener, one side is an engine side mounting surface and the other side is a catalyst side mounting surface, and each mounting surface is determined, but a special configuration that can share both mounting surfaces and It is also possible to do.
[0045]
That is, the size of the hole on each mounting surface is made to be the same, and the fear of incorrect assembly is eliminated.
[0046]
When fine adjustment is required in the holes on each mounting surface, one of the holes can be formed in a long hole shape to enable fine adjustment.
[0047]
【The invention's effect】
As described above in detail, according to the present invention, the engine-side mounting surface and the catalyst-side mounting surface of the stiffener are positioned substantially parallel to a plane perpendicular to the axial direction of the catalyst portion, so that the heat of the exhaust manifold can be obtained. The extension in the axial direction of the catalyst portion due to expansion or the like can be absorbed by a stiffener having a simple configuration, which is practically advantageous. In addition, since the engine side mounting surface and the catalyst side mounting surface of the stiffener are oriented in the same direction, the tightening direction can be set to one direction, enabling simultaneous processing, and the operator can use the tool. The distance moved can be reduced, and the assembling property can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view of a stiffener attachment state according to an embodiment of the present invention.
FIG. 2 is an enlarged plan view of a stiffener.
FIG. 3 is an enlarged front view of a stiffener.
FIG. 4 is a bottom view of a cylinder block.
FIG. 5 is a perspective view showing an assembled state of the stiffener.
FIG. 6 is a schematic enlarged explanatory view showing a state when stiffeners are misassembled.
FIG. 7 is an enlarged plan view of a stiffener showing another embodiment of the present invention.
8 is an enlarged cross-sectional view taken along line 8-8 in FIG.
FIG. 9 is a perspective view showing an assembled state of a stiffener showing the first prior art of the present invention.
FIG. 10 is a perspective view showing an assembled state of a stiffener showing a second prior art of the present invention.
[Explanation of symbols]
2 Engine 4 Cylinder block 10 Oil pan 14 Exhaust manifold 16 Cylinder head mounting flange 18 Branch pipe portion 20 Collecting portion 22 Catalyst portion 24 Stiffener 26 Engine side mounting surface 28 Catalyst side mounting surface 30 Connection step portion 32 Oil pan mounting surface 34 Stiffener Tightening female thread 36 Exhaust pipe mounting flange 38 Protrusion 40 Tightening bolt 42 First mounting hole 44 Second mounting hole 46 Stiffener mounting hole

Claims (3)

And a branch pipe portion in the exhaust manifold of an engine mounted on the cylinder head and the collecting portion to assemble the downstream side of the branch pipe part is provided, the catalyst portion is provided directly under the collecting part of the exhaust manifold, the catalyst unit cylinder the exhaust system support structure that is fixed to the engine via a stiffener formed by a plate-like member while being disposed on the side of the block, connecting to communication with the engine side mounting surface and the catalyst mounting surface them in the stiffener A step portion is formed, the engine side mounting surface and the catalyst side mounting surface are formed so as to be perpendicular to the axial direction of the catalyst portion and oriented in the same direction, and the engine side mounting surface and the catalyst The connection step portion is formed by bending with the side mounting surface, and the engine side mounting surface is mounted on the lower surface of the cylinder block and the catalyst side mounting surface Installed on the exhaust pipe mounting flange of the catalyst unit, and the mounting direction of the lower surface of the cylinder block and the exhaust side pipe mounting flange is made to be the same while the mounting direction of the lower surface of the cylinder block and the exhaust side pipe mounting flange is different The connecting stepped portion is formed in a crank shape corresponding to the difference in the mounting height position of the stiffener, and extends in the connecting stepped portion in the axial direction of the two bent portions with respect to each mounting surface and the catalyst portion. An exhaust system support structure for an engine characterized by comprising an extending portion . 2. The exhaust system support structure for an engine according to claim 1, wherein a lower surface of the cylinder block is formed on the same plane as an oil pan mounting surface . Exhaust pipe mounting first and second holes are provided at portions of the exhaust pipe mounting flange projecting in the manifold row direction, and the space between the first and second holes extends in the manifold row direction to form a substantially triangular shape. The extension part is provided with a stiffener attachment hole, and the stiffener attached to the extension part has a catalyst side attachment surface that protrudes away from the engine side attachment surface. And the distance from the first mounting hole provided on the engine side mounting surface to the oil pan mounting surface is set smaller than the distance from the second mounting hole provided on the catalyst side mounting surface to the projection. The exhaust system support structure for an engine according to claim 1.

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