JPS61142325A - Valve drive mechanism in internal combustion engine exhaust system - Google Patents

Abstract

PURPOSE:To make it possible to arrange a valve drive mechanism in a narrow section, in an engine in which valves are incorporated in guide passages for guiding exhaust gas from exhaust ports into guide passages which guide exhaust gas in the direction orthogonal to the exhaust ports, by providing a drive mechanism including a solenoid for opening and closing the valves each belonging to each engine cylinder in synchronism with each other. CONSTITUTION:Guide passages 22a, 22b are opened at their lower ends to the upper surfaces of exhaust ports 12a, 12b of two engine cylinders 10a, 10b, and are connected at their upper ends with a common external connecting passage 26 through L-like shape deflecting passages 24a, 24b. Butterfly valves 16 are incorporated in the boundary sections between the guide passages 22a, 22b and the exhaust ports 12a, 12b, and are opened and closed by a drive mechanism 34 in which arms 42 fixed to the externally projected ends of rotary shafts 30 of the valves 16 are linked to both ends of a bellcrank 38 through rods 40a, 40b so that the valves 16 are opened and closed in association with the rotation of the bellcrank 38.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drive mechanism for opening and closing a valve in an exhaust system for an internal combustion engine in which a pressure propagation passage is opened and closed by a swinging valve such as a butterfly valve. It is something.

(Prior Art) The applicant has already developed and filed an application for an exhaust system for a two-stroke engine as shown in FIG.

This device includes a first cylinder 10a and a second cylinder 10b connected to each other with a phase difference of 180°, exhaust ports 12a and 12b are connected by a pressure propagation passage 14, and the exhaust ports 12a and 12b of the pressure propagation passage 14 are located near the exhaust ports 12a and 12b. Each butterfly valve 16 is opened and closed by a drive mechanism (not shown), for example, by a drive mechanism (not shown).
The structure is such that the 1M4 is operated at 700 rpm, the butterfly valve 16 is opened in the low speed range, and the butterfly valve 116 is closed in the high speed range.

According to the above device, at low speeds when the butterfly valve 16 is open, a positive pressure wave is applied to the exhaust ports 12a, 12b by the resonance action of the pressure propagation passage 14 and the mufflers 13a, 13b connected to the respective cylinders. The butterfly valve 1 can prevent the air-fuel mixture from blowing through to improve the output, and when the pressure propagation passage 14 is in communication as shown in the output curves 18c and 18d in FIG. 9, the butterfly valve 1 is
In order to improve output by closing valve 6, high output is achieved over the entire rotation speed range.

However, when mounting such a two-stroke engine exhaust system on a motorcycle body, for example, the drive mechanism that drives the butterfly valve 16 must be placed in a narrow cylinder area, and it is difficult to make the entire system compact. There is an issue of whether to summarize them into

(Objective of the Invention) An object of the present invention is to provide a valve drive mechanism in an exhaust system for an internal combustion engine that can be compactly attached to an internal combustion engine 1180.

(Structure of the Invention) The present invention provides a guide passage for guiding exhaust gas from an exhaust port of an internal combustion engine having at least two cylinders in a direction crossing the exhaust port, and an internal combustion engine equipped with a valve near the exhaust port of the guide passage. In an exhaust system for an engine, a rotating shaft of a valve projects toward one side of an internal combustion engine, an arm is attached to the projecting end, and a rotary solenoid is disposed on the one side of the internal combustion engine. A pulp in an exhaust system for an internal combustion relief system, characterized in that a bell crank is provided on the rotation shaft of the bell crank, and the bell crank and the arm are connected by an O-rad, so that the valves of each cylinder are opened and OFF in synchronization. It is a drive mechanism.

(Example) In FIG. 1 showing the case where the present invention is applied to a water-cooled in-line two-air n2-cycle engine for an over-the-air engine, parts given the same reference numerals as those in FIG. 8 indicate the same or equivalent parts.

FIG. 1 is a side view of the cylinder and cylinder head portion of the engine of the present invention, seen from the left side in the direction of travel of the V-bike, and this engine is shown in FIG. The cylinders are mounted on the vehicle body with the cylinder arrangement direction along the longitudinal direction of the vehicle body.

In the M1 diagram, the M1 cylinder 10a, the second cylinder 1
Cooling water hoses 20a are connected to each side of 0b, and cooling water is supplied from a cooling water pump (not shown) to the cooling water hoses 20a. The first cylinder 10a and the second cylinder 10b have exhaust ports 12a and 12, respectively.
b, the exhaust port 12a of the first cylinder 10a opens toward the front of the vehicle body, and the exhaust port 12a of the first cylinder 10a opens toward the front of the vehicle body.
The exhaust port 12b of 0b is open toward the rear.

As shown in FIG. 3, the upper surface 1 of the exhaust ports 12a, 12b
The lower end portion of the guide passage 22a communicates with the portion facing the cylinder head 10C.

The guide passage 22a is formed within the wall thickness of the first cylinder 10a so as to rise toward the cylinder head 10c. Similarly, the second cylinder 10b has a guide passage 22b (
1 and 2) are provided.

The upper end of the guide passage 22a is continuous with one end of the direction change passage 24a, and the direction change passage 24a is formed within the thickness of the cylinder head 10c.

The direction change passage 24a is J: Sea urchin place f190 shown in FIG.
It is bent into an elbow shape, and the other end of the direction changing passage 24a extends toward the left side of the first cylinder 10a (FIG. 2). Also, the direction change passage 2 of the second cylinder 10b
4b is similarly formed, and the direction change passage 24b is 1
The second cylinder 10b along the outer periphery of the cylinder head 10C
It extends in a curved line toward the left side of the (Figure 2).

The direction change passages 24a and 24b are connected by an external connection passage Vs26 as shown in FIGS. 1 and 2, and the external connection passage 26 is connected to the cooling water outlet 20 along the left side of the engine.
It passes in the front-back direction so as to surround b. The pressure propagation passage 14 is formed by the external connection passage 26, the direction change passages 24a, 24b, and the guide passages 22a, 22b.

Note that the cooling water outlet 20b is connected to a radiator (not shown).

Near the exhaust ports 12a, 12b of the pressure propagation passage 14, that is, the guide passages 22a, 22b and the exhaust ports 12a, 12
As an example, a butterfly valve 16 (opening/closing valve) is provided at the boundary part b as shown in FIG. Although the details will be described later, when the butterfly valve 16 is closed, it has a curved surface that is substantially continuous with the inner surface 28 of the exhaust port 12.

The butterfly valve 16 has a rotating shaft 30 as shown in FIG.
The end of the rotating shaft 30 protrudes from the left side of the engine. Note that in FIGS. 3 and 4, 32a and 32b are cooling water jackets.

Next, the drive mechanism 34 for opening and closing the butterfly valves 16 of the guide passages 22a and 22b will be explained with reference to FIG. The drive mechanism 34 is formed from a rotary solenoid 36, a bell crank 38, rods 40a, b, an arm 42, etc., and is arranged below the external connection passage 26 on the left side of the engine.

The rotary solenoid 36 is fixed to the left side surface of the first cylinder 10a via seven flange 44a with a bolt 44b with a slight gap therebetween. A rotating shaft 46 of the rotary solenoid 36 protrudes into this gap, and the rotary solenoid 36 is fixed such that the rotating shaft 46 is perpendicular to the left side surface of the first cylinder 10a. Rotation @46
A bell crank 38 is fixed to the end of the bell crank 38. A rod 40a and a rod 40b are provided at both ends of the bell crank 38.
One end is rotatably supported.

The other end of the Orad 40a extends in front of the rotary solenoid 36 and is connected to an arm 42 of the butterfly valve 16 that opens and closes the guide passage 22a. The other end of the rod 40b extends rearward and is connected to an arm 42 of a butterfly valve 16 that opens and closes the guide passage 22b.

The rotary solenoid 36 is a control unit 48
By inputting from the control unit 48, the rotation shaft 46 is rotated in the direction of arrow A at a rotation angle of, for example, 67.5 degrees, and the arm 42 is connected to the
By rotating the butterfly valve 16, the butterfly valve 16 is turned. The rotary solenoid 36 is normally biased in the direction of the reverse arrow by the spring force of a built-in spring.

A rotation speed detection signal from the ignition device 50 is input to the control unit 48. For example, when the engine rotation speed reaches 700 rpm, the control unit 48
It has a function of outputting a drive current to the rotary solenoid 36 from the beginning.

As shown in FIG. 4, the arm 42 includes a rotating arm 52, a fixed arm 54, a holding spring 56, and the like. The fixed arm 54 overlaps the back surface of the rotating arm 52, is pressed against the rotating shaft 30, and is fitted so as to rotate together with the rotating shaft 30. The rotating arm 52 is tightened with a nut 60 via a collar 58, and the rotating arm 52 is rotatable about the rotating shaft 30, and a rod 40a is attached to the tip of the rotating arm 52. They fit together freely.

The rotating arm 52 and the fixed arm 54 are connected to the rotating shaft 3.
End 62 of retaining spring 56 wrapped around 0
They are biased in the circumferential direction of the rotating shaft 30 so that they overlap each other.

Next, details of the butterfly valve 16 will be explained. The butterfly valve 16 is connected to the guide passage 2 as shown in FIG.
Guide passages 22a, 22b are formed in close contact with the inner surfaces of 2a, 22b.
A substantially disc-shaped valve body 70 that closes the valve body 70 and a protruding portion 72 that protrudes from the lower surface of the valve body 70 facing the exhaust ports 12a and 12b.
It consists of

The valve body 70 and the protrusion 72 are integrally molded from a sintered metal. As shown in FIG.
protrudes from the lower surface of the valve body 70 except for the portion where it is fixed, and the diameter D2 of the protrusion 72 is set to be slightly smaller than the diameter D1 of the valve body 70. Two holes 74 are provided in the center of the valve body 70 for fixing the rotation shaft 30 with screws.

The shape of the lower surface 76 of the protrusion 72 is shown in a cross-sectional view taken along the center line 78 in FIG. Certain Figures 7 and 7a to 7
As shown in figure d, radius R ~ radius R4 (R1<R2<R3
According to R4), the exhaust port 12 is formed into a substantially continuous curved surface on the inner surface 28 of the exhaust port 12. Note that the center line 78 in FIG. 5 forms an angle of 24° with the center line 80 orthogonal to the rotation axis 30.

Next, the effect will be explained. The pressure propagation passage 14 is a guide passage 22
a, 22b1, direction change passage 24a, 24b1, and external connection passage 26, so that a space for arranging the drive mechanism 34 is secured on the left side of the engine. Further, the guide passages 22a and 22b are formed within the wall thickness of the first cylinder 10a and the second cylinder 10b, and the direction change passage 24a,
24b is formed within the thickness of the cylinder head 10C, so the structure is simple and the guide passage 22a122b and the fixed arms 54a, b can be easily connected.

Furthermore, the external connection passage 26 is arranged along the left side of the engine.
Therefore, a space for fixing the Ll-tally solenoid 36 to the first cylinder 10a below the external connection passage 26 is secured. Therefore, the pressure propagation passage 14 and the drive mechanism 34 are concentrated on the left side of the engine.

The drive mechanism 34 has an engine rotation speed of, for example, 700Qr.
pm, the spring force of the spring built into the rotary solenoid 36 holds the butterfly valve 16 in an open state to improve the output of the engine at low speeds. On the other hand, when the engine speed is, for example, 7000 rpm or higher, the rotary solenoid 36 rotates in the six directions of the arrows by the output current from the control unit 48 to simultaneously close the butterfly valves 16 in the guide passages 22a and 22b. Improve output.

When the butterfly valve 16 is closed, the holding spring 56 of the arm 42 uses its own elastic force to displace the fixed arm 54 and the rotating arm 52 in the circumferential direction of the rotating shaft 30, thereby guiding the valve body 70 of the butterfly valve 16. Passages 22a, 22b
This prevents excessive load from being applied to the valve body 70.

The drive mechanism 34 is a rotary solenoid 36 that connects the guide passage 2.
Since the butterfly valves 16 provided at 2a and 22b are opened and closed, only one rotary solenoid 36 is required.
The two butterfly valves 16 are opened and closed via the bell crank 38 and the rods 4Qa and b. Therefore, only one electric circuit is required to operate the rotary solenoid 36, which is suitable for motorcycles with limited battery capacity.

Moreover, compared to using a linearly operated solenoid, the rotary solenoid 36 and butterfly valve 1
Since the number of members interposed between 6 and 6 is reduced, the structure of the drive mechanism 34 is simplified, and the rotary solenoid 36 is
The rotation is transmitted to the butterfly valve 16 without causing play.

Since the protruding portion 72 of the butterfly valve 16 has a smaller diameter than the valve body 70, the butterfly valve 16 is connected to the guide passage 22a,
22b, the protrusion 72 and the guide passage 22a,
22b is separated from the inner surface of the protruding portion 7 by a gap δ as shown in FIG.
2 collide with the inner surfaces of the guide passages 22a, 22b and prevent the rotation of the butterfly valve 1'6.

When the butterfly valve 16 is closed, the lower surface 76 of the protrusion 72 is substantially continuous with the inner surface 28 as shown in FIG. the exhaust port 12a,
The output of the engine is improved by smoothing the flow of exhaust gas discharged to 12b.

(Effects of the Invention) As explained above, the valve drive mechanism in the exhaust system for internal combustion 81 according to the present invention is a guide for guiding exhaust gas from the exhaust port of an internal combustion engine having at least two cylinders in a direction intersecting the exhaust port. In an exhaust system for an internal combustion engine, which has a passage and a valve near the exhaust port of the guide passage, the rotating shaft of the valve protrudes toward one side of the internal combustion engine, and an arm is attached to the protruding end. One rotary solenoid is arranged on the one side of the figure, a bell crank is provided on the rotating shaft of the rotary solenoid, and the bell crank and the arm are connected with a rod to open and close the valves of each cylinder synchronously. As a result, the following effects can be achieved.

Since the rotary solenoid 36 is fixed to the left side surface of the first cylinder 10a below the external connection passage 26, the driver jIIJ34 can be placed in a narrow cylinder section of the engine. This gives the motorcycle a beautiful appearance with the engine part exposed to the outside.

Since a single rotary solenoid can open and close valves installed in multiple locations simultaneously, the entire device becomes more compact, and the synchronization of each valve becomes more accurate, reducing variations in performance. Ideal for multi-cylinder engines.

In addition, compared to the case where a linearly operating solenoid is used, there are fewer members interposed between the rotary solenoid and the valve, which simplifies the structure of the drive mechanism.
0 - The rotation of the rotary solenoid can be efficiently transmitted without causing any play in the valve, and less electricity is required to operate the rotary solenoid, so it is suitable for motorcycles where the capacity of the on-board battery is limited. suitable for

(Another Embodiment) (1) The present invention is applicable not only to the two-stroke engine of the embodiment, but also to the case where an exhaust chamber is provided at the exhaust port of a four-stroke engine, etc.
It can also be applied to A.

(2) The rotary solenoid 36 is not limited to the case where the rotation shaft 46 is fixed to the left side of the engine in a perpendicular position as in the embodiment; It can also be fixed in other positions.

(3) The swing valve (IFII closing valve) may be a butterfly valve, a notched cylindrical valve, a notched disc valve, or the like.

[Brief explanation of drawings]

Fig. 1 is a partial side view of a two-stroke engine to which the present invention is applied, Fig. 2 is a view taken in the direction of the ■ arrow in Fig. 1, and Fig. 3 is a partial view of the two-stroke engine in Fig. 2.
-■ Partial cross-sectional view, Figure 4 is a cross-sectional view of IV-TV in Figure 3,
Fig. 5 is a plan view of the butterfly valve, Fig. 6 is a view in the direction of the ■ arrow in Fig. 5, Fig. 7 is a sectional view taken along the -■ line in Fig. 5, and Fig. 7a is a sectional view taken along the line a-C in Fig. 7. , Figure 7b is a sectional view taken along line bb in Figure 7, Figure 7C is a sectional view taken along line CC in Figure 7, and Figure 7d is a sectional view taken along line 7 in Figure 7.
FIG. 8 is a structural diagram showing a conventional example, and FIG. 9 is a graph showing engine output. 1゜a...
First cylinder, iob...Second cylinder, 12a, 1
2b...Exhaust port, 14-...Pressure propagation passage, 16
...Butterfly valve, 22a122b...Guide passage, 24a, 24b...Direction change passage, 26...External connection passage, 28...Inner surface, 3o...Rotation shaft, 34
... Drive mechanism, 36 ... Rotary solenoid, 3
8... Bell crank, 40a, b... Rod, 42
...Arm, 70...Valve body, 72...Protrusion, 7
6...Bottom patent applicant: Kawasaki Chuo Kogyo Co., Ltd. Figure 3, 1st sinong

Claims (1)

[Claims] In an exhaust system for an internal combustion engine having a guide passage for guiding exhaust gas from an exhaust port of an internal combustion engine having at least two cylinders in a direction crossing the exhaust port, the guide passage has a valve near the exhaust port. A shaft is provided by protruding to one side of the internal combustion engine and an arm is attached to the protruding end, one rotary solenoid is arranged on the one side of the internal combustion engine, and a bell crank is provided on the rotating shaft of the rotary solenoid. A valve drive mechanism in an exhaust system for an internal combustion engine, characterized in that a bell crank and the arm are connected by a rod to open and close valves of each cylinder in synchronization.