JPH027225Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention provides for communication between the upstream ends of the exhaust passages of the exhaust manifold, and at least one pair of The present invention relates to an exhaust manifold for a multi-cylinder engine in which the exhaust passages are independent from each other and are integrally formed so as to share a part of their outer walls and intersect with each other.

Prior Art In a four-stroke multi-cylinder engine, for example, an in-line four-cylinder engine, in order to avoid exhaust interference in order to obtain high-speed performance, the ignition order is non-consecutive as shown in FIGS. 1 and 2. The upstream ends of the exhaust passages 03a and 03d of the exhaust manifold are communicated with the exhaust ports 02a and 02d of the cylinders 01a and 01d, respectively, and the exhaust passages 03
Gather the downstream ends of a and 03d together, and
Exhaust port 02 of No. 3 cylinder 01b, 01c
b, 02c are the exhaust manifold exhaust passages 03b,
The upstream ends of the exhaust passages 03c were communicated with each other, and the downstream ends of the exhaust passages 03b and 03c were brought together.

Problems to be solved by the invention In such an exhaust manifold, the first,
One of the fourth exhaust passages 03a and 03d always intersects with the second and third exhaust passages 03b and 03c.

Then, there is a gathering part 04a where the downstream ends of the exhaust passages 03a and 03d are gathered, and the exhaust passage 03b,
An exhaust manifold is integrally formed by casting or the like with no gap between the downstream ends of the downstream ends of the exhaust manifolds 04b and 04b. When connected together, when the outer wall of the exhaust passage is heated by the passage of high-temperature exhaust gas generated during engine operation and thermal expansion occurs,
Since the longest first exhaust passage 03a that intersects with the second and third exhaust passages 03b and 03c has a large thermal expansion, the stay mounting portion 05 moves in the X direction from the first exhaust port 02a toward the fourth exhaust port 02d. As it moves, the cross-sectional shape of the gathering portion 04 deforms into a parallelogram shape, and the stay 06 may be damaged by the force in the X direction due to this deformation.

Means and Effects for Solving the Problems The present invention relates to an improvement of the exhaust manifold for a multi-cylinder engine that overcomes the above-mentioned difficulties, and in which the upstream end of the exhaust passage is communicated with the exhaust port of each cylinder of the multi-cylinder engine. In an exhaust manifold for a multi-cylinder engine, the downstream ends of the exhaust passages are gathered together, and at least one pair of exhaust passages are independent of each other and are integrally formed so that the outer walls thereof partially share and intersect. By forming the outer shape of the cross section of the exhaust passage downstream end gathering part into a substantially rectangular shape and making the wall thickness of the corner part thicker than the wall thickness of the side part, the cross section of the exhaust passage downstream end gathering part is formed. It is possible to increase the shear rigidity along the surface and prevent its deformation as much as possible.

Embodiment An embodiment of the present invention illustrated in FIGS. 3 to 9 will be described below.

A cylinder block 1 of the illustrated four-stroke gasoline engine installed in a passenger car has four cylinders 2 arranged in series inside it, and each cylinder 2 has an exhaust port 4 provided in a cylinder head 3 at the top thereof. Each of the exhaust ports 4 is connected to four exhaust ports 5 through the exhaust port 4, and each exhaust port 4 is provided with an exhaust valve 6, and the downstream end opening 7 of the exhaust port 5 is open to the side surface of the cylinder head 3.

Further, the intervals between the downstream end openings 7a, 7b, 7c, and 7d of the exhaust port 5 in the cylinder head 3 are set at equal intervals, as shown in FIG.

Further, the exhaust manifold 10 is formed by casting FCD55S, and the upper part of the exhaust manifold 10 is brought into contact with the side surface of the cylinder head 3, and is inserted into the bolt hole 24 of the upper flange 23 of the exhaust manifold 10 and screwed into place. The upper part of the exhaust manifold 10 is integrally attached to the cylinder head 3 with bolts 25.

The branched upstream portions 12b and 12c of the second and third exhaust passages 11b and 11c communicating with the second and third downstream end openings 7b and 7c are curved in the direction of approaching each other, and then the partition wall 14a is bent. They are curved downward in a close and parallel state with each other separated by an intermediary,
The branched downstream portions 13b and 13c are merged at their downstream ends to form a merged portion 16a.

Further, the first exhaust passage 11a, in which the first branch upstream part 12a communicates with the first downstream end opening 7a, is located closer to the cylinder block 1 than the second and third exhaust passages 11b and 11c, and intersects them. The branched downstream portions 13a and 13d are curved toward the fourth exhaust passage 11d and curved downward, and the branched downstream portions 13a and 13d are closer to the fourth exhaust passage than the second and third branched downstream portions 13b and 13c.
are located near the cylinder 2d and are merged at the downstream end thereof to form a merge portion 16b.

Further, the branch peripheral wall 17a of the first exhaust passage 11a is connected to the second and third exhaust passages 11b and 11, as shown in FIGS. 3, 6, and 7.
It is integrally joined via the branch part peripheral walls 17b, 17c of c and the partition wall 14b, and
As shown in the figure and FIG. 5, the branch upstream portions 12a and 12b and 12c and 12d are integrally joined via branch reinforcement connecting portions 19a and 19b.

Furthermore, the merging portion 16a is connected to the cylinder block 1.
It is curved in the direction approaching the confluence part 1.
6b is bent in a direction away from the cylinder block 1, and the merging portions 16a, 16b are arranged in a direction parallel to the arrangement direction of the cylinders 2, as shown in FIG. 5, and as shown in FIG. like,
The merging section is partitioned via a partition wall 20.

Further, as shown in FIG. 9, the merging portions 16a and 16d also have a cross-sectional shape close to a rectangular cross-section,
Merging portion peripheral walls 21a, 21 of merging portions 16a, 16b
The radius of curvature of the outer peripheral surface of the merging peripheral wall corner portions 22a, 22b at b is smaller than the radius of curvature of the inner peripheral surface thereof, and the wall thickness of the merging peripheral wall corner portions 22a, 22b is smaller than that of the merging peripheral wall corner portions 21a, 21b. The wall thickness is set to be thicker than the side wall thickness.

Furthermore, the lower flange 26 of the exhaust manifold 10
, an exhaust pipe (not shown) is integrally connected, and an upper portion 30 of a substantially L-shaped stay 29 is integrally attached to a boss 27 protruding toward the engine side of the confluence portion 16 of the exhaust manifold 10 with a bolt 28. , the lower part 31 of the stay 29 is integrally attached to the cylinder block 1 by a bolt 32,
The inertia force and vibration force acting on the exhaust manifold 10 are firmly fixed and supported at the upper and lower parts thereof.

Since the embodiments shown in FIGS. 3 to 9 are configured as described above, when the engine starts operating, high-temperature exhaust gas generated in the combustion chamber flows out from the exhaust port 4 to the exhaust port 5. It passes through the exhaust passage 11 of the exhaust manifold 10, and the exhaust manifold 10 is heated to a high temperature and expands.

In this case, the exhaust passage 11a communicating with the first downstream end opening 7a in the cylinder head 3 is connected to the second,
Located closer to the cylinder block 1 than the third exhaust passages 11b and 11c and in contact with the third exhaust passages 11b and 11c,
Since it is curved to cross this and face the fourth exhaust passage 11d, when the exhaust manifold 10 is heated and expanded, the exhaust passage opens in the Y direction as shown in FIGS. 5 and 9. 11a expands, and the amount of expansion is such that the exhaust passage 11a is different from the other exhaust passage 1.
Because it is longer than 1b, 11c, and 11d,
As a result, the merging portion peripheral wall 21 of the merging portion 16
is about to cause a torsional deformation as shown by the broken line in FIG. However, as mentioned above, the peripheral wall 2 of the confluence part
In No. 1, the wall thickness of the corner portions 22a, 22b of the merging peripheral wall is thicker than the wall thickness of the side portions of the merging portion peripheral walls 21a, 21b, and the rigidity against this torsional deformation is large, so that the aforementioned torsional deformation is prevented.

For this reason, the Y applied to the stay 29 from the boss 27
The force in this direction is small, and damage to the stay 29 is prevented.

Further, the branching part peripheral wall 17 and the merging part peripheral wall 21 of the exhaust manifold 10 are made thick only in necessary parts and thin in other parts, so that the exhaust manifold 10 is light and can be manufactured at low cost.

Effects of the invention As described above, in the exhaust manifold of this invention,
By making the wall thickness at the corner of the cross section of the downstream end gathering portion of the exhaust passage thicker than the wall thickness at the side thereof, the collection along the cross section can be made thicker without increasing the overall wall thickness of the manifold. By increasing the shear rigidity of the section and preventing its deformation, it is possible to prevent damage to the stay connected to the boss of the gathering section near the engine.

[Brief explanation of the drawing]

Fig. 1 is a schematic front view of a conventional exhaust manifold that avoids exhaust interference and improves high-speed performance, Fig. 2 is a view taken from - arrow in Fig. 1, and Fig. 3 is an exhaust of a multi-cylinder engine according to the present invention. FIG. 4 is a perspective view of an embodiment of the manifold, FIG. 5 is a front view showing the exhaust passage and boss of the exhaust manifold in dotted lines, and FIGS. 6 and 7 are FIG. of-
8 is a horizontal cross-sectional view taken along the line - in FIG. 5, and FIG. 9 is a cross-sectional view taken along the line - in FIG. 6. 1... Cylinder block, 2... Cylinder, 3... Cylinder head, 4... Exhaust port, 5... Exhaust port, 6
...exhaust valve, 7...downstream end opening, 10...exhaust manifold, 11...exhaust passage, 12...branch upstream section, 13...
Branch downstream part, 14...partition wall, 15...edge, 16...
Merging portion, 17... Branching portion surrounding wall, 18... Branching surrounding wall corner, 19... Branching portion reinforcing connection portion, 20... Merging portion partition wall, 21... Merging portion surrounding wall, 22... Merging surrounding wall corner, 2
3... Upper flange, 24... Bolt hole, 25... Bolt, 26... Lower flange, 27... Boss, 28... Bolt, 29... Stay, 30... Upper part, 31... Lower part,
32...Bolt.

Claims (1)

[Scope of utility model registration request] The upstream ends of the exhaust passages communicate with the exhaust ports of each cylinder of the multi-cylinder engine, and the downstream ends of the exhaust passages are brought together, and at least one pair of exhaust passages are independent of each other and intersect by sharing a part of their outer walls. In the exhaust manifold for a multi-cylinder engine integrally formed as shown in FIG. An exhaust manifold for a multi-cylinder engine that is characterized by being thicker than it is thick.