JP3862243B2 - Exhaust manifold for V8 engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust manifold for a V-type 8-cylinder engine.
In this specification, 1R refers to the rightmost cylinder frontmost cylinder of the V-type 8-cylinder engine, and 4L refers to the leftmost bank last cylinder. Accordingly, 2R, 3R, and 4R are the second, third, and fourth cylinders from the front on the right bank side, respectively, and 1L, 2L, and 3L are the first, second, and third cylinders from the front on the left bank side, respectively. It is.
[0002]
[Prior art]
Conventionally, exhaust systems of large vehicles such as trucks and buses have been fitted with cast iron exhaust manifolds that collectively send exhaust gas discharged from the engine to the downstream side, but the engine has a large capacity. Accordingly, V-type engines are widely adopted, and in such engines, exhaust manifolds are connected to the left and right banks, respectively.
[0003]
As shown in FIG. 4, conventionally, in this type of exhaust manifold 1, a plurality of branches 3, 5, 7, and 9 connected to the exhaust ports are arranged in parallel with the collector 11, and expansion due to heat is taken into consideration. Thus, the collector 3 is divided into two, and the fitting portion 13 can absorb the expansion due to heat.
By the way, in the V-type 8-cylinder engine, the firing order (explosion order) of each cylinder is set for the purpose of reducing engine vibration, and generally 1R-1L-4R-4L-3L-2R-2L-3R. The firing sequence is the most widely used.
[0004]
[Problems to be solved by the invention]
However, in the structure in which a plurality of branches 3, 5, 7, and 9 are arranged in series as in the exhaust manifold 1, the ignition in adjacent cylinders in the same bank is continuously performed due to the ignition order. If this is done, the exhaust gas is continuously discharged into the same exhaust manifold, causing backflow in the exhaust gas, and so-called exhaust gas interference such as poor exhaust gas flow. Was pointed out.
Therefore, recently, a dual type exhaust manifold 15 as shown in FIG. 5 has been proposed as an exhaust manifold to be mounted on the left bank of a V-type 8-cylinder engine.
[0005]
The exhaust manifold 15 includes a collector 17 and two connection pipes 19 and 21 connected to the collector 17.
The collector 17 includes branch portions 23 and 25 that are bifurcated from the collecting portion 17a, a 3L branch 27 that is integrally formed with one branch portion 23, and a 4L branch that is formed with the other branch portion 25. 29, annular fitting portions 31, 33 for connecting the connection pipes 19, 21 are formed at the ends of the branch portions 23, 25, respectively.
[0006]
The connection pipes 19 and 21 are connected to 1L and 2L exhaust ports via brackets 35, respectively, and annular fitting portions 37 and 39 connected to the fitting portions 31 and 33 are connected to the end portions. In this structure, short connecting pipes 41 are respectively fitted, and the connecting pipe 19 is connected to the branching portion 23 and the connecting pipe 21 is connected to the branching portion 25. Although not shown, seal members are attached to the outer circumferences of both ends of the connection pipe 41 so as to make the fitting portion airtight.
[0007]
Thus, according to the exhaust manifold 15, the exhaust gas interference is prevented as compared with the exhaust manifold 1 shown in FIG.
However, in the exhaust manifold 15, the two connection pipes 19 and 21 connected to the collector 17 and the branch parts 23 and 25 thereof , and the connection pipes 19 and 21 are connected to the branch parts 23 and 25. many parts since it takes two of the connecting pipe 41 which connects to, Thus also, it takes a fitting portion 31,33,37,39, which connects the two connecting pipes 19 and 21 to the collector 17, correspondingly The exhaust manifold 1 is bulky and the weight is also increased.
[0008]
The present invention has been devised in view of such circumstances, and an object of the present invention is to provide an exhaust manifold for a V-type 8-cylinder engine which prevents exhaust gas interference and reduces the weight.
[0009]
[Means for Solving the Problems]
In order to achieve such an object, an exhaust manifold for a V-type 8-cylinder engine according to claim 1 is a V-type 8-cylinder engine having an ignition sequence of 1R-1L-4R-4L-3L-2R-2L-3R . the cast-iron exhaust manifold connected to the left bank, a collection section bifurcation bifurcated, 2L to one branch portion, and a collector branch is provided which is connected to the exhaust ports of 4L, the collector is fitted and connected to the end of the other branch portion, fitting 1L, composed of the connection pipe branch is provided which is connected to the exhaust ports of 3L, the connection pipe to the end portion of the branch portion A fitting portion to be connected is provided between 3L and 4L, and a partition wall that partitions the 1L and 3L exhaust gas flow paths and the 2L and 4L exhaust gas flow paths is provided in the collector.
[0010]
(Function)
According to the first aspect of the present invention, when the engine is driven, the exhaust gas flows from the 1R through the branch through the branch according to the preset ignition sequence, and then the exhaust gas from the 1L flows through the branch. Then, the exhaust gas passages flow down, and the exhaust gases from 4R, 4L, 3L, 2R, 2L, and 3R sequentially flow down through the respective exhaust gas passages through the respective branches.
[0011]
And it, a partition wall provided in the collector of d Kizo strike manifold, to prevent interference of the exhaust gas flowing down the exhaust gas passage.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the invention according to claim 1 will be described in detail with reference to the drawings.
[0013]
Figure 1 shows a cast iron exhaust manifold hold of which is connected to the 1R-1L-4R-4L- 3L-2R-2L-3R right bank of the V-type 8-cylinder engine which is a firing order of the figure, 43 Is a collector integrally provided with branches 45 and 47 connected to the exhaust ports of 3R and 4R, and 49 is a connection pipe fitted and connected to an annular fitting portion 51 provided at an end of the collector 43. The connection pipe 49 is integrally provided with branches 53 and 55 connected to the exhaust ports 1R and 2R. And the exhaust manifold 59 for right banks is comprised by fitting the annular fitting part 57 provided in the edge part of the connection pipe 49 in the said fitting part 51. As shown in FIG.
[0014]
In the collector 43, a partition wall 65 that divides the 3R and 4R exhaust gas passages 61 and the 1R and 2R exhaust gas passages 63 is provided with a connection flange 67 formed from the base of the branch 45. 43 is provided over the exhaust gas deriving portion 43a, and the partition wall 65 prevents the exhaust gas interference from the cylinders adjacent in the ignition order.
[0015]
2 and 3 show a cast iron exhaust manifold according to an embodiment of the present invention connected to a left bank of a V-type 8-cylinder engine. The exhaust manifold 69 is connected to a collector 71 and the exhaust manifold 69. And one connection pipe 73.
Thus, the collector 71 has two long and short branch portions 77 and 79 branched from the gathering portion 71a where the connection flange 75 is formed, and 2L and 4L of one long branch portion 79 is formed. Two branches 81 and 83 connected to the respective exhaust ports are integrally provided.
[0016]
An annular fitting portion 85 for fitting the connection end of the connection pipe 73 is formed at the end of the other branch portion 77. As shown in the figure, the fitting portion 85 has 3L and 4L. It is arrange | positioned in the substantially intermediate part. The connection pipe 73 is integrally provided with branches 87 and 89 connected to the 1L and 3L exhaust ports. Also, in the collector 71, the partition wall 95 for partitioning the exhaust gas passage 93 of the exhaust gas passage 91 and 2L and 4L of 1L and 3L are exhaust gas outlet portion of the collector 71 from the branch portion of the branch portion 77, 79 The partition wall 95 prevents exhaust gas interference from cylinders adjacent in the ignition order.
[0017]
The exhaust manifold hold 69 of the present embodiment, since the exhaust manifold 59 connected to the right bank of the engine is configured to, when the engine is driven in accordance with the ignition order set in advance, first, the 1R Exhaust gas flows down the exhaust gas flow path 63 through the branch 53, then exhaust gas flows down from 1L through the branch 87 through the exhaust gas flow path 91, and 4R, 4L, 3L, 2R, 2L, 3R From the exhaust gas flow through the exhaust gas passages 61, 63, 91, 93 sequentially through the branches 47, 83, 89, 55, 81, 45, respectively.
[0018]
And the partition wall 65 provided in the exhaust manifold 59 prevents the interference of the exhaust gas flowing down the exhaust gas passages 61, 63. Similarly, the partition wall 95 provided in the exhaust manifold 69 is provided with the exhaust gas passage 91, The interference of the exhaust gas flowing down 93 is prevented.
As described above, the present embodiment is configured so that the exhaust gas from the adjacent cylinders in the ignition order does not continuously flow through the same exhaust gas flow path, so that interference of the exhaust gas can be reliably prevented. As a result, the engine output and fuel consumption can be improved, and smoke can be reduced.
[0019]
Further, in the present embodiment, the fitting portion between the branch portion 77 and the connection pipe 73 in the exhaust manifold 69 is set between 3L and 4L, so that the exhaust manifold 69 as a whole can be reduced in weight.
That is, instead of the structure of the exhaust manifold 69, the branch portion 77 on the collector 71 side is extended between 2L and 3L, a thick annular fitting portion 85 is provided at the end, and 3L If the branch 89 is integrally formed with the branch part 77, when the collector 71 is cast, there is a waste between the branch 89 and the branch 81 on the other branch part 79 side.
[0020]
Therefore, as described above, in the present embodiment, the fitting portion between the branch portion 77 of the collector 71 and the connection pipe 73 is set between 3L and 4L, and the branch 89 is provided on the connection pipe 73 side. The generation of meat can be prevented.
[0021]
Therefore, according to the present embodiment, the weight can be reduced as compared with such a structure, and the weight is reduced compared with the conventional example shown in FIG.
In addition, the number of parts is reduced as compared with the conventional example of FIG. 5, and the conventional example of FIG. 5 has thick fitting portions 31 , 33 , 37 , 39 addressed to the top and bottom. Since the exhaust manifold 69 according to the present embodiment has only one fitting portion 85, the exhaust manifold 69 is not bulky as compared with the conventional example, and the thickness can be reduced, and the weight can be reduced. Is possible.
[0022]
【The invention's effect】
As described above, according to the exhaust manifold for a V-type 8-cylinder engine according to claim 1, exhaust gas interference can be surely prevented, and the number of parts can be reduced and the weight can be reduced as compared with the prior art. It became.
[Brief description of the drawings]
1 is a decomposition front view of Rue Kizo strike manifold is connected to the right bank of the V-type 8-cylinder engine.
FIG. 2 is a front view of an exhaust manifold according to one embodiment of the present invention connected to a left bank of a V-type 8-cylinder engine.
FIG. 3 is a plan view of the exhaust manifold shown in FIG. 2;
FIG. 4 is a front view of a conventional exhaust manifold.
FIG. 5 is a front view of another conventional exhaust manifold.
[Explanation of symbols]
43, 71 Collector 45, 47, 53, 55, 81, 83, 87, 89 Branch
49, 73 Connection pipes 59, 69 Exhaust manifolds 61, 63, 91, 93 Exhaust gas passages 65, 95 Partition wall 71a Collecting portion
77, 79 branch

Claims (1)

An exhaust manifold (69) made of cast iron connected to the left bank of the V-type 8-cylinder engine , which has been ignited in order of 1R-1L-4R-4L-3L-2R-2L-3R, is bifurcated from the collecting portion (71a). a collector (71) for branching part (77, 79) is branched, 2L to one branch portion (79), the branch which is connected to the exhaust ports of 4L (81 and 83) are provided in the collector (71 And a connecting pipe (73) provided with branches (87, 89) connected to the end portions of the other branch portion (77) of 1) and 3L and connected to the exhaust ports of 1L and 3L. fitting portion for fitting connecting the connection pipe (73) to the end of the branch portion (77) to (85) 3L, provided between 4L, in the collector (71), an exhaust gas passage of 1L and 3L (91) and 2L and 4L exhaust gas passages (93 V-type 8-cylinder exhaust manifold for an engine, characterized in that a partition wall (95) for partitioning and.

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