JPH0270919A - Exhaust controller - Google Patents

Abstract

PURPOSE:To increase output over the whole region of the high and low revolution regions by installing a valve mechanism in which the sectional area of an exhaust passage and the capacity of the communication part are increased and reduced by opening and closing a communication hole to each exhaust hole in a chamber member and suppressing the formation of the bottom part of the output in the low and intermediate revolution region. CONSTITUTION:In the high revolution region of an engine, the exhaust passages 3a-3d of each exhaust pipe 3 are allowed to communicate each other through a valve mechanism 7, and the passage sectional area of each exhaust passage 3a-3d and the capacity of the communication part can be increased. Therefore, the output can be increased by effectively utilizing the interference of exhaust, and the disposal of the increase of the exhaust quantity is permitted. Further, in the low or intermediate revolution region of the engine,the part between the exhaust passages 3a-3d of each exhaust pipe 3 can be cut off, or the number of communication can be reduced by the valve mechanism 7, and the passage sectional area of each exhaust passage 3a-3d and the capacity of the communication part can be reduced. Therefore, the negative effect due to the pulsation of exhaust can be reduced, and the output can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an exhaust control device provided in an exhaust pipe of a multi-cylinder engine mounted on a motorcycle or the like.

(Prior Art) Generally, in a multi-cylinder engine, an exhaust system is used in which a plurality of exhaust pipes led from each cylinder are collected and connected to an air silencer. In this system, the intake efficiency of the engine is improved by utilizing the pulsation of exhaust pressure that occurs in each exhaust pipe.
It is known that the output of the engine can be improved. Usually, motorcycles aim to improve output in the high rotation range, and the natural frequency of the exhaust pipe is set accordingly.

(Problem to be solved by the invention) However, when trying to improve the output in the high rotation range, the negative effect due to exhaust pulsation increases in the low and medium rotation range.
There is a drawback that there is a valley in the output.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an exhaust control device that can improve output over the entire high and low rotation range without producing a trough in the output in the low and medium rotation range. With the goal.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides an exhaust pipe in which a plurality of exhaust pipes led from each cylinder of a multi-cylinder engine are collected and connected to an exhaust muffler.
The exhaust pipes are arranged in parallel, and a cylindrical chamber member is connected to one side of these pipes so that their axes intersect with each other,
The chamber member is characterized in that a valve mechanism is provided within the chamber member to open and close communication holes with each of the exhaust pipes and to expand and contract the cross-sectional area of the exhaust passageway and the volume of the communicating portion.

(Function) According to the present invention, the cross-sectional area of the exhaust passage, the communication state, and the volume of the communication part of the exhaust pipe can be varied according to the engine speed or load, and the optimum exhaust state according to the operating state can be obtained. .

That is, in a high rotation range of the engine, the valve mechanism allows the exhaust passages of the exhaust pipes to communicate with each other, and expands the cross-sectional area of each exhaust passage and the volume of the communicating portion. Thereby, it is possible to improve the output by effectively utilizing the interference of the exhaust gas, and it is also possible to cope with an increase in the exhaust gas m.

In addition, in the low and medium speed range of the engine, the valve mechanism closes off or reduces the number of communicating water between the exhaust passages of each exhaust pipe, and reduces the cross-sectional area of the exhaust passage and the volume of the communicating portion. In addition, the negative effects caused by exhaust pulsation can be reduced and the output direction improved.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 3 shows the external appearance of a motorcycle equipped with the exhaust control device according to the present invention, and FIGS. 1, 2, and 4 to 9 illustrate the configuration and operation of the exhaust control device, FIG. 10 shows the engine output characteristics.

As shown in FIG. 3, in this embodiment, v
! Is it derived from each cylinder of the 4-cylinder 4-stroke engine 2? IJ number of exhaust pipes 3 are connected to an exhaust silencer 5.

As shown in FIG. 2, the exhaust pipes 3 are arranged in parallel in the lateral direction, and a cylindrical chamber member 5 is connected to the upper side of these pipes so that their axes intersect. And as shown in Figure 1,
A valve mechanism 7 is provided in the chamber member 5 and has a function of opening and closing the communication hole 6 with each exhaust pipe 3 and expanding and contracting the passage cross-sectional area of the exhaust passages 3a, 3b, 3c, and 3d and the volume of the chamber 5a as a communicating portion. has been established.

That is, the valve part 'II 7 has a drum 8 as a valve element that rotates within the chamber member 5. As shown in FIGS. 4 and 5, this drum 8 has a part of the peripheral wall 8a with a communication hole 6
A gate valve portion 9 is used to close the gate. Further, as shown in Figure 56 and Figure 7, the drum 8 has two exhaust passages 3b in other parts of the peripheral wall 8a.

3c and the other exhaust passage 3a.
, 3d has a concave constriction portion 11 that makes the concave portion 3d slightly constricted. Furthermore, as shown in FIGS. 8 and 9, the drum 8 has a second series of 3ffl windows 12 that communicate with all the exhaust passages 3a, 3b, 3c, and 3d. Note that the drum 8 is driven by a drive unit 1 such as a pulley provided on a shaft 13 at the end.
Rotationally driven by 4.

Then, the drum 8 is rotated by a predetermined angle, and the exhaust passages 3a, 3b, 3c of each exhaust pipe 3 are opened as shown in FIG.

3d, the communication cross-sectional area of all the exhaust passages 3a, 3b, 3c, and 3d is narrowed and the communication hole 6 is enlarged. In this case, as shown by curve a in FIG. 10, an output characteristic is obtained in which the output is high in the low rotation range.

In addition, as shown in FIG. 7, the exhaust passages 3b, 3 of the two exhaust pipes 3
13131115110 of drum 8 is placed in c
When the state is set to 1, the two exhaust passages 3b.

3C communicates with each other, and the other exhaust passages 3a and 3d are made independent so that the cross-sectional area of the passages is narrowed. In this case, the first
As shown by the curve tab in Figure 0, an output characteristic with high output in the middle rotation range is obtained.

Furthermore, as shown in FIG. 9, all exhaust passages 3 of exhaust ff13
When the second communication windows 12 of the drum 8 are arranged in the a, 3b, 3c, and 3d, all the exhaust passages 3a, 3b
, 3c', and 3d communicate with each other via the chamber 5a. In this case, the same condition as when the length of the exhaust pipe is shortened occurs, and as shown by curve C in FIG. 10, an output characteristic with high output in the high rotation range is obtained.

Therefore, by controlling the rotation of the drum 8 to the state shown in FIG. 5 in the low engine speed range, the state shown in FIG. 7 in the medium speed range, and the state shown in FIG. 9 in the high engine speed range by a control unit (not shown), the first
As shown by curve A in Figure 0, only outputs higher than the intersections of curves a, b, and c can be obtained.

According to the configuration of the above embodiment, in the high rotation range of the engine, the valve mechanism 7
, 3d are communicated with each other, and each exhaust passage 3a,
By increasing the cross-sectional area of the passages 3b, 3c, and 3d and the volume of the communicating portion, it is possible to effectively utilize the interference of exhaust gas to improve the output and cope with an increase in the amount of exhaust gas.

In addition, in the low and medium speed range of the engine, the valve mechanism 7 shuts off or reduces the number of exhaust passages 3a, 3b, 3c, and 3d of each exhaust pipe 3, and
By reducing the cross-sectional area of the passages 3c and 3d and the volume of the communicating portion, it is possible to reduce the negative effects caused by exhaust pulsation and improve the output. In other words, as shown by curve A in Fig. 10, the output characteristics a, b, and c of low, medium, and high-speed rotation types are shown.
A synthetic characteristic of is obtained, and the valley part of the output can be removed. Therefore, the cross-sectional area of the exhaust passage of the exhaust pipe 3, the communication state, and the volume of the communication portion can be varied according to the engine speed or load, and the optimum exhaust state according to the operating state can be obtained.

Note that the number of exhaust pipes, the number of exhaust pipes connected by the valve mechanism, etc. are not necessarily limited to those in the above embodiments, and can of course be changed in various ways.

〔Effect of the invention〕

As described above, according to the exhaust control device of the present invention, the cross-sectional area of the exhaust passage of the exhaust pipe, the communication state, and the volume of the communication part can be varied according to the engine speed or load, and the optimal exhaust gas can be adjusted according to the communication state. condition can be obtained, and it is possible to prevent the occurrence of output valleys in the low and medium speed range of the engine.
The effect is that the output can be improved throughout the high and low speed range.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal (gi) view showing an embodiment of the exhaust fiIJI8 device according to the present invention, Fig. 2 is a perspective view from below showing the same embodiment, and Fig. 3 is an exhaust control device according to the same embodiment. Figure 4 is a side view of a motorcycle equipped with a valve body;
Fig. 5 is a sectional view taken along line V-v in Fig. 4 showing the position of the valve body in the low rotation range, Fig. 6 is a sectional view showing the valve body at a different angle from the state shown in Fig. 4, and Fig. 7. is a sectional view taken along the ■-VI line in Fig. 6 showing the position of the intermediate valve body, Fig. 8 is a sectional view showing the valve body at a different angle from the state in Fig. 4, and Fig. 9 is a high rotation A sectional view taken along the line II-IN in FIG. 8, not showing the position of the valve body in the area,
FIG. 10 is a characteristic diagram showing the effect. 2...Engine, 3...Exhaust pipe, 3a, 3b, 3G
, 3d...exhaust passage, 4...exhaust silencer, 6...
Communication hole, 7... Valve mechanism, 8... Drum (valve body). 3a (JA, Jc, 3d) Fig. μ-7-子ゝ3α (31, 3c, 3d) J

Claims (1)

[Claims] In a system in which a plurality of exhaust pipes led from each cylinder of a multi-cylinder engine are assembled and connected to an exhaust silencer, the exhaust pipes are arranged in parallel, and a cylindrical shape is formed with the axes intersecting on one side of the exhaust pipes. A valve mechanism is provided in the chamber member that has the function of opening and closing the communication hole with each of the exhaust pipes and expanding and contracting the cross-sectional area of the exhaust passageway and the volume of the communication portion. An exhaust control device featuring: