JPH0420983Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an improvement of a collective exhaust pipe in which exhaust pipes of a multi-cylinder engine are connected.

[Prior art]

Some multi-cylinder engines employ collective exhaust pipes in order to improve the exhaust efficiency of the engine by utilizing reflected waves of exhaust gas flowing in each exhaust pipe, that is, exhaust pulsations, thereby improving the output of the engine.

By the way, in collective exhaust pipes, it is known that the engine speed range in which exhaust pulsations are matched differs depending on the length from the starting end of each exhaust pipe to the collective part. That is, in order to increase the exhaust efficiency in the high rotational speed range of the engine, each exhaust pipe 12, 1 is
4, 16, 18 starting ends 12a, 14a, 16
The length _L1 from a, 18a to the gathering part 20 is shortened, and in the low and medium rotation speed range of the engine,
In order to improve exhaust efficiency, each exhaust pipe 12, 14,
Each starting end 12a, 14a, 16a, 1 of 16, 18
Increase the length L ₂ from 8a to the gathering part 20 (L ₂ >
L ₁ ) It is necessary to take. In addition, Figures 5 and 6
In the figure, reference numeral 22 is a muffler, and 24 is a pipe connecting the muffler 22 and the connecting portion 20.

However, according to the conventional collective exhaust pipes 10 described above, each exhaust pipe 12, 14, 16, 18
Since the lengths from each starting end 12a, 14a, 16a, 18a to the gathering part 20 are fixed, the exhaust efficiency can be increased in a rotation speed range other than a specific engine rotation speed range, and the output of the engine can be improved. I couldn't do it.

[Purpose of invention]

In view of the above-mentioned problems, this invention provides a collective exhaust pipe that increases exhaust efficiency over a wide range of rotations, from low rotation to high rotation of a multi-cylinder engine, and improves engine output.

[Structure of the idea]

In order to achieve the above-mentioned purpose, this invention:
A communication means for communicating the exhaust pipes with each other is interposed between each starting end and the collecting part of the collective exhaust pipe, so that the length from the starting end of each exhaust pipe to the substantial collecting part is the same as that of the engine. It is designed so that it can be changed depending on the rotation speed range.

〔Example〕

Hereinafter, one embodiment of the collective exhaust pipe according to the present invention will be described in detail.

FIG. 1 is a perspective view showing a collective exhaust pipe 40 according to the present invention, showing a so-called 4in1 type collective exhaust pipe, and particularly shows one installed in a 4-stroke, 4-cylinder engine for a motorcycle. There is. Further, the same parts as in FIGS. 5 and 6 are indicated by the same reference numerals.

In this collective exhaust pipe 40, each exhaust pipe 12, 1
4, 16, 18 starting ends 12a, 14a, 16
The length L ₃ between a, 18a and the collecting portion 20 is set to be relatively long, and is set to improve exhaust efficiency in the low and medium rotational speed range of the engine. On the other hand, each starting end 12a, 14 of this collective exhaust pipe 40
A, 16a, 18a and the gathering part 20, that is, at a position a relatively short distance L ₄ (L ₄ <L ₃ ) from each of the starting ends 12a, 14a, 16a, 18a, each exhaust pipe 12, 14 is provided. , 16, 18 is provided with a communication means 50 that collects the exhaust gas flowing through the exhaust gases. This communication means 50 is connected to each of the exhaust pipes 12 and 1 which are divided into two parts, as shown in FIG.
4, 16, and 18, and a connecting member 52 rotatably supported in the center of the connecting member 52, and between the circumferential surfaces of the connecting member 52, each of the exhaust pipes 12,
A passage 54a that connects 14, 16, and 18 with each other
A cylindrical valve 54 is provided through the valve 54.

In addition, among the connecting members 52, the partition walls 90, which are disposed before and after the above-mentioned cylindrical valve 54 and rotatably support the cylindrical valve 54, gradually change as they approach the cylindrical valve 54. The plate thickness t is increased.

In the connecting member 52 of the gathering means 50, there are four independent passages 56, 58, 60, 62.
is formed (Fig. 4), and each end of the divided exhaust pipes 12, 14, 16, 18 is formed as shown in Fig. 2.
As shown in FIG. 3 showing the BB cross section, each end of each corresponding passage 56, 58, 60, 62 is fitted.

On the other hand, as shown in Fig. 4 showing the CC cross section of Fig. 2,
The passages 56, 58, 60, 62 facing the peripheral surface 54b of the cylindrical valve 54 are provided with holes 56a, 58.
The holes 56a, 58a, 60a, 62a are normally closed by the circumferential surface 54b of the valve 54. Then, when the valve 54 rotates by a predetermined angle, the valve 54 rotates by a predetermined angle.
4 and each hole 56a, 58a, 60a, 62a of each passage 56, 58, 60, 62 formed in the communication member 52 matches, so that each passage formed independently 56, 58, 6
0 and 62 are communicated with each other through the passage 54a of the valve 54. Therefore, in this case, the exhaust gas discharged through the passages 56, 58, 60, and 62 will be collected through the passage 54a of the valve 54.

Note that since the partition wall 90 that rotatably supports the cylindrical valve 54 is formed so that its plate thickness t increases as it approaches the cylindrical valve 54 (Fig. 2), the connecting member The exhaust gas passes through the connecting member 5 smoothly.
Attenuation of reflected waves (exhaust pulsation) of exhaust gas passing through the exhaust gas 2 is reduced as much as possible, and it becomes possible to effectively utilize exhaust pulsation to improve exhaust efficiency. Note that in FIG. 4, reference numerals 64 and 66 are bearings that rotatably support the valve 54, respectively.

Further, the communication means 50 is provided with a driving means 70 for driving the valve 54, as shown in FIG. The driving means 70 includes an arm 72 connected to one end of the valve 54, as shown in FIG.
, a return spring 74 that biases the valve 54 in the closing direction, a servo motor 76 , a wire 80 connecting the arm 72 and a pulley 78 fixed to the shaft end of the servo motor 76 , and the servo motor 76 . It is composed of a controller 82.

According to the above-mentioned driving means 70, when the engine is started and its rotational speed is in the low-medium rotational speed range, the exhaust gas passing through each exhaust pipe 12, 14, 16, 18 is directed to the collecting section located at the rear. Since they gather only at 20, the exhaust efficiency in the low and medium rotational speed range of the engine increases, and the output of the engine in that rotational speed range improves. On the other hand, the engine speed is detected by the controller 82, and when the value reaches a high speed range (for example, 8000 rpm or more), the servo motor 76 is driven. Then, the rotating arm 72 is rotated by a predetermined angle via the wire 80, and the passage 54a of the valve 54 is connected to each passage 56,
Holes 56a, 58 formed in 58, 60, 62
a, 60a, and 62a. Therefore, the exhaust gases passing through each of the exhaust pipes 12, 14, 16, and 18 are collected in the connecting member 52 of the collecting means 50, increasing the exhaust efficiency in the high rotation range, and increasing the engine speed in that rotation range. The output will be improved.

Although the above embodiment describes a 4-in-1 collective exhaust pipe 40 installed in a 4-stroke, 4-cylinder engine, the present invention is of course not limited to the above-mentioned embodiment, and can be applied to, for example, a 2-stroke, multi-cylinder engine. Alternatively, the present invention may be applied to a collective type exhaust pipe in which two of a plurality of exhaust pipes are combined. Furthermore, although the above embodiment describes a collective exhaust pipe installed in a motorcycle engine, the present invention is of course not limited to the above embodiment, and may also be applied to a collective exhaust pipe for automobiles. good. Further, in the above embodiment, a case has been described in which one collecting means is interposed between the starting end of each exhaust pipe and the collecting part, but the present invention is of course not limited to the above embodiment, and can achieve desired engine output characteristics. In response to the,
A plurality of collecting means may be interposed at different positions, and the length of the portion where the exhaust gas collects may be changed in multiple stages. Further, in the above embodiment, the connecting member 52 of the communication means 50 is connected to each exhaust pipe 12, 1.
4, 16, and 18, the present invention is of course not limited to the above embodiments, and the connecting member 52
may be formed integrally with each exhaust pipe 12, 14, 16, 18.

[Effect of idea]

As explained above, in this invention, a plurality of exhaust pipes arranged independently for each cylinder of a multi-cylinder engine are extended to the vicinity of the entrance of the silencer, and the exhaust pipes are arranged near the entrance of the silencer. In a collective type exhaust pipe in which multiple exhaust pipes are assembled at the same time, between the starting end of each exhaust pipe and the collective part near the entrance of the muffler,
A communication means is provided to change the length between the starting end and the collecting part of each exhaust pipe according to the engine speed,
This communication means allows the length between the starting end and the converging part of each exhaust pipe to change depending on the engine speed, thereby effectively utilizing exhaust pulsation over a wide range of engine speeds to increase exhaust efficiency. , the output of the engine can be increased.

Further, a communication means for changing the length between the starting end and the gathering part of each exhaust pipe according to the engine speed is provided with a cylindrical valve, and is arranged before and after the cylindrical valve to partition each of the exhaust passages. It is a partition wall,
Since the partition wall is formed so that the plate thickness becomes thicker as it approaches the cylindrical valve, the passage of exhaust gas becomes smoother, and the effective use of reflected waves to improve exhaust efficiency is further promoted. can be done.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a collective exhaust pipe according to the present invention, Fig. 2 is an enlarged AA sectional view of Fig. 1, Fig. 3 is a BB sectional view of Fig. 2, and Fig. 4 is a sectional view of Fig. 2. The CC sectional view, FIGS. 5 and 6 are perspective views showing conventional collective exhaust pipes, respectively. 12, 14, 16, 18...exhaust pipe, 40...
Collective exhaust pipe, 50...communication means, 54...valve, 54a...passage, 56a, 58a, 60a,
62a... hole.

Claims (1)

[Claims for Utility Model Registration] A plurality of exhaust pipes arranged independently for each cylinder of a multi-cylinder engine are extended to the vicinity of the inlet of the muffler 22, and the plurality of exhaust pipes are arranged in the vicinity of the inlet of the muffler 22. In a collective type exhaust pipe in which a plurality of exhaust pipes are assembled together at the same time, a communication means 50 disposed between a starting end and a terminal end of the plurality of independent exhaust pipes, Rotatably interposed between the exhaust pipes,
A cylindrical valve 54 having a passage 54a for communicating the exhaust pipes with each other in a direction perpendicular to its rotation axis, and partition walls disposed before and after the cylindrical valve 54 to partition the exhaust pipes. a communication means 50 having at least a partition wall 90 whose plate thickness increases as it approaches the cylindrical valve 54; The passage 54a of the valve is rotated to a position where it communicates with each of the plurality of independent exhaust pipes, and the plurality of independent exhaust pipes are simultaneously brought together at the location where the communication means 50 is provided, and the lower part of the engine is - In the middle rotation speed range, the cylindrical valve 54 is rotated around the circumferential surface 5 of the valve excluding the passage 54a.
4b to a position where the plurality of independent exhaust pipes are prevented from communicating with each other, and a driving means 70 that simultaneously collects the plurality of independent exhaust pipes near the entrance of the muffler 22. A collective exhaust pipe featuring: