JPH0656100B2 - Exhaust system for multi-cylinder engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for a multi-cylinder engine, and more particularly to the shape of an exhaust passage extending from each cylinder of a multi-cylinder engine.

[Prior Art] A major factor that determines engine performance is the shape of an exhaust passage extending from a cylinder of an engine. In particular,
In many multi-cylinder engines, the exhaust passages of the respective cylinders merge at the exhaust merging passage. In this case, the length from the exhaust port of each cylinder to the exhaust merging passage greatly affects the performance of the engine.

Here, in the related art, since the exhaust merging passage is formed in the cylinder body, it is extremely difficult to appropriately change the length from the exhaust port to the exhaust merging passage according to the required engine performance. .

[Problems to be Solved by the Invention] That is, in the related art, since the exhaust passage including the exhaust merging passage is integrally molded in the cylinder body, the length from the exhaust port to the exhaust merging passage is changed according to the engine performance. There is a problem that it is difficult to change it appropriately, and thus it is difficult to obtain desired engine performance.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to easily adjust or change the length from the exhaust port of each cylinder to the exhaust merging passage in a multi-cylinder engine. An exhaust system for a multi-cylinder engine is provided.

[Means for Solving the Problems] The present invention is provided with a plurality of cylinders, and the exhaust ports of the respective cylinders are joined together in at least one exhaust merging passage, and the respective cylinders are formed so as to form a substantially V shape on the left and right. In an exhaust system for a multi-cylinder engine arranged, an exhaust merging passage is formed in an exhaust cover attached to a cylinder body, and the exhaust merging passage is configured to communicate with an exhaust port of each cylinder. The exhaust cover is provided between the cylinders arranged in the substantially V shape, and the exhaust passages are arranged so as to intersect with each other.

[Operation] With this configuration, the exhaust merging passage is formed not inside the cylinder body but inside the exhaust cover. Therefore, by changing the shape and position of the exhaust merging passage in the exhaust cover, the exhaust merging passage can be easily removed from each cylinder. The distance to the exhaust merging passage can be changed, and since the exhaust cover is provided between the cylinders arranged in the substantially V shape, even if the exhaust merging passage is lengthened, the entire engine Can be miniaturized.

Furthermore, since the exhaust passages are arranged so as to intersect with each other, the length from the exhaust port of each cylinder to the exhaust merging passage can be made longer in a small space, thereby achieving desired engine performance. The optimum length of the exhaust passage can be obtained.

[Examples] The present invention will be described below based on Examples shown in the drawings.

First, FIGS. 1 to 5 schematically show a first embodiment of the present invention, in which the engine is a 6-cylinder V-type 2-cycle engine.

Reference numeral 10 denotes a cylinder body, and six cylinders are formed and arranged so that three cylinders each have a substantially V shape on the left and right. 12
Is a cylinder head, 14 is a crankcase, 16 is an intake manifold, 18 is a carburetor, 20 is an intake silencer,
22 is a cowling. An exhaust cover 24 is mounted on the outer wall of the cylinder body 10 at a position between the V-shaped portions of the cylinder body 10, and an exhaust merging passage described later is formed in the exhaust cover 24. Reference numeral 26 in FIG. 4 is a flywheel magnet.

As shown schematically in FIGS. 2 and 3 for the sake of clarity, three cylinders 28, 30, 32 are arranged horizontally on one side of the cylinder body 10 divided into V-shapes, that is, a bank. From the exhaust ports of these cylinders, that is, the exhaust ports 29, 31, 33, the exhaust passages 34, 3 are respectively provided.
6 and 38 extend, and these exhaust passages are connected to the cylinder body 1
There is an opening at the end face of 0. The exhaust cover 24 is mounted on the end surface of the cylinder body 10. An exhaust merging passage 40 is integrally formed in the exhaust cover 24, and the exhaust receiving passages 42, 4 of the exhaust merging passage 40 are formed.
4, 46 are connected to the exhaust passages 34, 36, 38.

Similarly, for the other V-shaped bank of the cylinder body 10, the exhaust ports 49, 5 of the three cylinders 48, 50, 52 are also provided.
Exhaust passages 54, 56, 58 extend from 1, 53 and are connected to exhaust receiving passages 62, 64, 66 of an exhaust merging passage 60 different from the exhaust merging passage 40 of the exhaust cover 24, respectively.

As easily shown in FIGS. 1, 4, and 5, the exhaust passages 34, 36, 38 of one bank are arranged so as to intersect the exhaust passages 54, 56, 58 of the other bank. Here, the two exhaust passages are arranged so as not to interfere with each other, and for example, the exhaust passage 54 passes through the space between the adjacent exhaust passages 34, 36 of the other bank at the intersection. The exhaust passage at this intersection is just at the joining position between the cylinder body 10 and the exhaust cover 24, but it is not limited to this, and the intersection may be provided on the cylinder body 10 side or the exhaust cover 24 side. It goes without saying that it is good.

According to the embodiment having such a structure, the exhaust merging passages 40 and 60 are separate from the cylinder body 10 and are attached to the cylinder body 10.
Since it is formed in No. 4, the passage length from the exhaust port of each cylinder to the exhaust merging passage 40 or 60 can be made longer than in the conventional case, and when adjusting the passage length. Can be easily performed only by adjusting the positions of the exhaust merging passages 40 and 60 formed in the exhaust cover 24. Further, according to this embodiment, since the exhaust passage of one bank is arranged so as to intersect with the exhaust passage of the other bank, the length from the exhaust port of each cylinder to the exhaust merging passage should be made longer. Is possible. Therefore, it is possible to obtain the optimum exhaust passage length according to the desired performance of the engine.

Next, FIGS. 6 and 7 show a second embodiment of the present invention, in which the same or corresponding parts as those of the embodiment shown in FIGS. 1 to 5 are designated by the same reference numerals, and these parts are shown. The detailed description of is omitted.

The second embodiment differs from the first embodiment described above in that the exhaust passages 34, 36, 38 of one bank and the exhaust passages 54, 56, 58 of the other bank are arranged in parallel with each other without intersecting each other. Is.

Also in this embodiment, since the exhaust merging passages 40 and 60 are formed in the exhaust cover 24 which is separate from the cylinder body 10, the distance from the exhaust port of each cylinder to the exhaust merging passages 40 and 60 is different from the conventional one. It can be made longer in comparison, and its distance can be easily adjusted.

Next, FIG. 8 shows a third embodiment of the present invention, which is an engine in which a plurality of cylinders are arranged in a line, unlike the case of the above-described embodiment. The exhaust cover 24 is attached to the side surface of the cylinder body 10, and only one exhaust merging passage 68 is provided in the exhaust cover 24.
There is no difference from the above-mentioned embodiment except that it is provided in the. That is, the exhaust merging passage 68 is formed in the exhaust cover 24, and the distance between the exhaust port 29 on the cylinder body 10 side and the exhaust merging passage 68 can be made long. Therefore, this embodiment also has substantially the same effects as the above-mentioned embodiment.

[Effects] As described above, according to the present invention, the exhaust merging passage is formed in the exhaust cover which is separate from the cylinder body, and the exhaust cover is arranged in a substantially V-shape formed in each cylinder. Since it is provided between the cylinders, the overall size of the engine is reduced and the length from the cylinder exhaust port to the exhaust confluence passage, which is a major factor in determining engine performance, is changed according to the desired engine performance. It has an excellent effect that it becomes easy to do.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an embodiment of an exhaust system for a multi-cylinder engine according to the present invention, FIG. 2 is a schematic sectional view taken along the line II-II of FIG. 1, and FIG. 5 is a schematic cross-sectional view taken along the line III-III in FIG. 4, FIG. 4 is a schematic left side view of FIG. 1, and FIG.
FIG. 6 is a schematic sectional view taken along the line VV of FIG. 4, FIG. 6 is a schematic cutaway plan view showing a second embodiment of the present invention, and FIG. 7 is a schematic left side view of FIG. FIG. 8 is a cutaway plan view showing only the essential parts of the third embodiment of the present invention. 10 ... Cylinder body 24 ... Exhaust cover 28, 30, 32, 48, 50, 52 ... Cylinder 29, 31, 33, 49, 51, 53 ... Exhaust port 40, 60, 68 ... Exhaust merging passage

Claims (1)

[Claims] 1. Exhaust gas of a multi-cylinder engine comprising a plurality of cylinders, wherein the exhaust ports of the respective cylinders merge at at least one exhaust merging passage, and the respective cylinders are formed so as to form a substantially V shape on the left and right sides. In the device, an exhaust merging passage is formed in an exhaust cover attached to a cylinder body, and the exhaust merging passage is configured to communicate with an exhaust port of each cylinder. Further, the exhaust cover is formed into the substantially V-shape. An exhaust system for a multi-cylinder engine, characterized in that it is provided between the cylinders arranged in the above, and each exhaust passage is arranged so as to intersect with each other.