JPH05202730A - Valve unit in exhaust system of internal combustion engine - Google Patents

Abstract

PURPOSE:To have a valve unit giving priority to noise suppressing at the time of low load and giving priority to back pressure at the time of high load by projectingly forming an extension covering an outer circumference in the range where an opening/closing valve provided on a main body with a bimetal as fulcrum is tilted from perpendicular by a predetermined angle and by connecting the main body to an exhaust pipe. CONSTITUTION:At one end of a main body 17a made of a short pipe, a plate- state opening/closing valve 17b is provided by connected with a bimetal 19 at its part in capable of opening/closing with the bimetal 19 as fulcrum. And at one end of the main body 17a, an extension 17c is projectingly formed covering an outer circumference of the opening/closing valve 17b over the range where the opening/closing valve 17b is tilted outward by a predetermined angle from the perpendicular attitude against an axis of the main body 17a. The other end of the main body 17a so formed is connected to a predetermined exhaust pipe 13 in an exhaust system. By this, a valve unit can be manufactured without modifying the existing noise suppressing structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve unit in an exhaust system of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in an exhaust system of an internal combustion engine, as a means for opening / closing one of branch exhaust pipes or opening / closing a predetermined inner pipe in a silencer, a flat open / close valve is simply controlled to be opened / closed by a bimetal. (Actual exploitation 57-53013
Gazette), which controls the opening and closing of the on-off valve by transformation of a shape memory alloy (Japanese Utility Model Laid-Open No. 61-62225), and which controls the opening and closing of the on-off valve by an actuator provided outside the silencer (actual 60-110615).

[0003]

By the way, in a silencer for an internal combustion engine, an opening / closing valve is provided in a predetermined exhaust pipe in the silencer, and the opening / closing valve is opened to open the exhaust resistance when the engine is running at high rotation and high load. It has been known that the back pressure reduction priority type is achieved by reducing the above, and the engine is closed and changed to the noise reduction priority type when the engine is idling or at low rotation and low load.

If, for example, the above-mentioned conventional bimetal type (FIGS. 20 to 23) is applied as the opening / closing control means of the opening / closing valve in the exhaust pipe in such a silencer, the following problems occur.

That is, as shown in FIG. 21, the on-off valve 2
Is attached to the vertical end opening 1a of the exhaust pipe 1 in a vertical position at room temperature, the open / close valve 2 opens greatly as shown in FIG. Although its purpose is achieved,
Although the end opening 1a should be closed when the engine is in the idle state or in the low rotation and low load state, FIG.
As shown in FIG. 3, the on-off valve 2 is slightly opened, and the sound deadening priority type is not provided.

This is because the on-off valve 2 is assembled at room temperature, and the inside of the muffler is not at room temperature when the engine is rotating, but it is always above room temperature. Further, it is conceivable to apply a conventional type in which a shape memory alloy is used instead of the above bimetal, but under the present circumstances where the transformation temperature of the shape memory alloy is 100 ° C. or lower, opening / closing control is performed within the range of 100 ° C. or higher. In the muffler that must be done, it cannot be used in reality.

Further, when the means for opening and closing by the actuator is applied as shown in FIG. 24, in order to operate the opening / closing valve 5 from the outside of the silencer, a controller for controlling the drive source such as electricity and pneumatic pressure, the actuator 4 and the like. The means for protecting the operating shaft 6 and the operating shaft from high temperature, the means for preventing exhaust gas leakage from the penetrating portion of the operating shaft, and the means for protecting external parts such as actuators from flying stones are required. , Its control is complicated and expensive.
Further, as in the above-mentioned conventional muffler having an opening / closing valve directly in the exhaust pipe, the entire muffler or most of the structure has a dedicated design and cannot be easily changed from the conventional fixed muffler. In some cases, even a manufacturing facility is required exclusively, which hinders the commercialization of the muffler and is extremely expensive.

The present invention solves the above problems,
It is possible to manufacture a silencer that prioritizes noise reduction when the engine is idling or at low rotation and low load, and that prioritizes back pressure reduction when the engine is at high rotation and high load, without modifying the existing silencer structure. The purpose is to propose a valve unit.

[0009]

In order to solve the above-mentioned problems, the first invention is to provide a plate-like on-off valve (17b) at one end of a main body (17a) made of a short pipe,
A part of it is connected by a bimetal (19) so that it can be opened and closed with the bimetal (19) as a fulcrum, and an opening / closing valve (17b) is provided at one end of the main body (17a).
From the vertical position with respect to the axis of the body (17a) to the body (1
7a) has an extension (17c) projectingly formed so as to cover the outer circumference of the on-off valve (17b) over a range inclined by a predetermined angle, and the other end of the main body (17a) is connected to a predetermined exhaust pipe in the exhaust system. It is characterized by connecting to.

Further, in the second invention, an opening / closing valve (17b) is connected to one end of a main body (17a) made of a short pipe, a part of which is connected by a bimetal (19), and the bimetal (19) is used as a fulcrum. The open / close valve (17b) is formed by a valve plate (17g) and a flange (17h) provided on the outer periphery of the valve plate (17g) so that the flange (17h) can reach a predetermined high temperature from room temperature. ) Is set so as to be located in the main body (17a), and the other end of the main body (17a) is connected to a predetermined exhaust pipe in the exhaust system.

[0011]

In the first aspect of the invention, at the normal temperature when the engine is stopped, the open / close valve (17b) is in the vertical posture shown by the solid line A in FIG. 5 and closes the downstream portion of the exhaust pipe (13). ..

In the idling state of the engine or in the low rotation and low load state above the normal temperature and below the predetermined temperature, the bimetal (19) is deformed to open and close the open / close valve (17).
b) swings in the extension (17c). Therefore, in this range, the closed state of the downstream portion of the exhaust pipe (13) is maintained, and the function of the silencer with silence priority is exerted.

When the engine reaches a predetermined temperature or higher due to high rotation and high load conditions, the bimetal (19) is further deformed and the opening / closing valve (17b) is rotated to the outside of the extension portion (17c), so that the main body (17a). The front end side of the exhaust pipe, that is, the downstream portion of the exhaust pipe (13) is largely opened to increase the flow area. Therefore, in this range, the exhaust gas flow amount in the exhaust pipe (13) is increased, and the function as a silencer of the back pressure reduction priority type is exerted.

In the second aspect of the invention, at room temperature when the engine is stopped, as shown by the solid line A in FIG. 14, the collar (17h) is inside the main body (17a), and the exhaust pipe (1
The downstream part of 3) is blocked.

When the engine is in an idling state or a low rotation and low load state, that is, at room temperature or higher and at a predetermined temperature or lower, the valve plate (17g) swings in the opening direction due to the deformation of the bimetal (19). , A part of the brim (17h) is present in the main body (17a), and the closed state of the end portion of the main body (17a), that is, the downstream portion of the exhaust pipe (13) is maintained, and the silencer of silence priority type Exert the function of.

When the temperature becomes higher than a predetermined temperature due to the high rotation and high load condition of the engine, the bimetal (19) is further deformed and the opening / closing valve (17f) is further moved in the opening direction, and the collar (17) is moved.
h) escapes from the end of the body (17a) and
The end of a), that is, the downstream portion of the exhaust pipe (13) is largely opened to increase the flow area. Therefore, in this range, the exhaust gas flow amount in the exhaust pipe (13) is increased, and the function as a silencer of the back pressure reduction priority type is exerted.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention shown in FIGS. 1 to 3 will be described. In FIG. 1, 10 is a silencer main body for an internal combustion engine, 11 is an inlet pipe, 12 is an outlet pipe, 13 and 14 are a plurality of chambers 15a, 15b, 15
The exhaust pipes 16a and 16b communicating with c are partition walls.

A valve unit 17 is fitted and connected to the end of a specific exhaust pipe 13 of the exhaust pipes 13 and 14. The shape and assembly of the valve unit 17 will be described in detail.

Main body 17a of the valve unit 17
Is formed in a cylindrical shape whose axial length L is short.
An open / close valve 17b is provided at a downstream end of the open / close valve 17b by a connecting plate 18 made of a flexible metal material and fixed between the bottom of the open / close valve 17b and the bottom of the main body 17a.
b swings in the axial direction of the main body 17a with the connecting plate 18 as a fulcrum. Further, a bimetal 19 is attached to the outer surface of the connecting plate 18, and when the opening / closing valve 17b is assembled at room temperature, the opening / closing valve 17b is attached.
The temperature of the bimetal 19 is set so that is perpendicular to the axis of the main body 17a.

The outer peripheral shape of the opening / closing valve 17b is formed so that a slight gap is formed between the opening / closing valve 17b and the main body 17a, and the amount of exhaust gas leaking from this gap is reduced.

At the downstream end, which is one end of the main body 17a,
An extension portion 17c having an inner wall surface along the outer peripheral surface movement locus of the on-off valve 17 is formed in a range in which the on-off valve 17b inclines from the vertical state to the downstream side of the main body 17a by a predetermined angle with the bimetal 19 as a fulcrum. There is. That is, the end surface 17d of the extension portion 17c has the bimetal 19
The part protrudes forward from the vertical line by a predetermined angle θ, and the upper part of the extension part 17c is bent slightly downward as it extends forward.

An upstream end 17e which is the other end of the main body 17a
Is formed to have an inner diameter that fits on the outer peripheral surface of the downstream end 13a of the exhaust pipe 13. The operation of this embodiment will be described.

The upstream end 17e of the valve unit 17
Is fitted and connected to the outer periphery of the downstream end 13a of the exhaust pipe 13 in the silencer having no ordinary valve shown in FIG. 4 as shown in FIG. 1, and is fixed by welding or the like to assemble the valve unit 17. wear.

In this assembled state, at room temperature when the engine is stopped, the opening / closing valve 17b is in the vertical state as shown by the solid line A in FIG. When the engine is idling or at low rotation and low load, at a temperature higher than room temperature and lower than a predetermined temperature, the bimetal 19 is deformed by a predetermined amount in proportion to the temperature, and the opening / closing valve 17b is changed from A to B in FIG. It swings within the range, that is, within the extension portion 17c. Therefore, the opening / closing valve 1 is provided at the downstream portion of the exhaust pipe 13.
It is kept closed by 7b. Therefore, in the muffler as shown in FIG. 1, the function as the muffling priority type muffler in which the muffling effect is increased is exhibited.

Next, when the inside of the silencer reaches a temperature higher than the predetermined temperature due to the high rotation and high load condition of the engine, the bimetal 19 is further deformed in proportion to the temperature, and the opening / closing valve 17b is changed from B in FIG. In the range of C, it swings in proportion to the temperature. Therefore, in the high rotation and high load state, the downstream portion of the exhaust pipe 13 is largely opened. Therefore, in the silencer as shown in FIG. 1, the function as a silencer of the back pressure reduction priority type that reduces exhaust resistance is exerted.

The valve unit 17 and the exhaust pipe 13
The connection with the main body 17a side of the valve unit 17 is performed by fitting the outer peripheral surface of the exhaust pipe 13 as shown in FIG.
As shown in FIG. 6, a structure in which both are fitted as a straight pipe, a structure in which the main body 17a side is expanded and fitted as shown in FIG. 6, and a structure in which the exhaust pipe 13 side is narrowed and fitted as shown in FIG. ..

Further, as a method of fitting the main body 17a side to the inner peripheral surface of the exhaust pipe 13, a structure in which both of them are fitted as a straight pipe as shown in FIG. 8, and a main body 17a side is squeezed and fitted as shown in FIG. The structure may be such that the exhaust pipe 13 side is expanded and fitted as shown in FIG.

FIG. 11 shows a second embodiment of the present invention, in which the outer peripheral shape of the opening / closing valve 17b is changed to that of the opening / closing valve 1b.
Between the 7b and the extension portion 17c, a predetermined amount of exhaust gas flow area 2
The diameter is made considerably smaller than the inner diameter of the extension portion 17c so that 0 occurs.

In this embodiment, when the engine is idling or when the engine speed is low and the engine load is low, a small amount of exhaust gas is discharged through the exhaust pipe 13, and when the engine is in a high engine speed and high load, the on-off valve 17b is to be fully opened. Applicable in case.

FIG. 12 shows the third embodiment of the present invention. In the first embodiment (FIG. 11), the shape of the extension portion 17c is reduced to a smaller diameter toward the front, and the end face 1 thereof is formed.
The inner diameter of 7d is close to the outer circumference of the opening / closing valve 17.

According to the present embodiment, the exhaust flow area 20 is gradually reduced as the temperature rises in the range of the engine idling state or the low rotation and low load state, and the open / close valve 17 is increased in the high rotation and high load state. Can be applied to the case where it is desired to fully open and exhaust a large amount of exhaust gas through the exhaust pipe 13.

FIG. 13 shows a fourth embodiment of the present invention. The main body 17a and its extension 1 in the first embodiment are shown.
7c, the opening / closing valve 17b is a semi-cylindrical type in which the side on the side of the opening / closing valve 17b, which is the swing fulcrum, is a straight line. It should be noted that the shape other than the semi-cylindrical shape may be square or the like.

FIG. 14 shows a fifth embodiment of the present invention. In the present embodiment, the main body 17a of the valve unit 17 is formed in a cylindrical shape having a short axial length L, and the downstream end 17e thereof is cut and formed perpendicularly to the axial center of the main body 17a. An open / close valve 17f is provided at a downstream end of the open / close valve 17f by a connecting plate 18 made of a metallic flexible material fixed between the bottom of the open / close valve 17f and the bottom of the main body 17a. It is designed to swing as. Further, the connecting plate 18
A bimetal 19 for opening and closing the opening / closing valve 17f according to the temperature rise is attached to the outer surface of the.

The open / close valve 17f includes a valve plate 17g,
The outer peripheral portion of the valve plate 17g includes a flange portion 17h provided on a portion other than the attachment portion of the connecting plate 18. The valve plate 17f has the outer peripheral shape of the main body 17
It is formed of a disk having a diameter slightly smaller than the inner peripheral surface of the downstream end portion of a.

As for the collar portion 17h, the valve plate 17g is shown in FIG.
As shown in FIG. 4, in a state of being inclined from the downstream end 17e of the main body 17a into the main body 17a by a predetermined angle θ,
It is formed in a shape that covers the inner peripheral surface of the exhaust pipe between the valve plate 17g and the downstream end 17e of the exhaust pipe.

The outer peripheral surface of the collar portion 17h has a curved surface similar to the curved surface drawn by the outer peripheral surface of the valve plate 17g when the valve plate 17g swings back and forth around the connecting plate 18 and the bimetal 19. The collar portion 17h is formed so that the main body 1
It does not interfere with the inner peripheral surface of 7a.

The opening / closing valve 17f is attached by a connecting plate 18 and a bimetal 19 so that the valve plate 17g is inclined inward from the downstream end 17e of the main body 17a by a predetermined angle θ at room temperature. This inclination angle θ is
The angle θ is set so that the valve plate 17g reaches the downstream end 17e due to the deformation of the bimetal 19 when the temperature is raised to a predetermined temperature immediately before the downstream end of the main body 17a should be opened.

When the temperature is raised above the predetermined temperature,
Due to the deformation of the bimetal 19, the opening / closing valve 17f swings further forward, and the downstream end 17e of the main body 17a is opened.

The operation of this embodiment will be described. Open / close valve 17f at room temperature when the engine is stopped
As shown by the solid line A in FIG. 14, the valve plate 17g is in a state of being inclined inward.

In a temperature range above normal temperature and below a predetermined temperature, such as when the engine is idling or under low rotation and low load conditions, the bimetal 19 is raised or lowered by that temperature.
The opening / closing valve 17f is changed from A to B in FIG.
It swings within the range of, that is, within the angle θ of FIG. Therefore, the downstream portion of the exhaust pipe 13 is maintained in a closed state by the valve plate 17g of the opening / closing valve 17f and the flange portion 17h. Therefore, in the muffler as shown in FIG. 1, the function as the muffling priority type muffler in which the muffling effect is increased is exhibited.

Next, when the inside of the silencer reaches a temperature higher than the predetermined temperature due to the high rotation and high load condition of the engine, the opening / closing valve 17f is opened as indicated by B in FIG. 14 due to the deformation of the bimetal 19.
To the position of C. Therefore, in the high rotation and high load state, the downstream side of the exhaust pipe 13 is largely opened, and the muffler as shown in FIG. 1 exhibits a function as a back pressure reduction priority muffler that reduces exhaust resistance.

FIG. 15 shows a sixth embodiment of the present invention, in which a valve plate 17g and a collar 17 of an opening / closing valve 17f are provided.
The h is formed to have a diameter considerably smaller than the inner diameter of the exhaust pipe 3 so that a somewhat large flow area 20 is formed between the outer peripheral surface thereof and the inner peripheral surface of the main body 17a.

In this embodiment, a small amount of exhaust gas is discharged through the exhaust pipe 13 when the engine is idling or when the engine speed is low and the load is low, and the open / close valve 17f is fully opened when the engine is high speed and high load. It can be applied when a large amount of exhaust gas is to be discharged through the exhaust pipe 13.

FIG. 16 shows a seventh embodiment of the present invention. In the fifth embodiment (FIG. 14), when the valve plate 17g is inclined inward of the main body 17a,
The collar 17h is formed so as to be parallel to the axis of the main body 17a.

According to the present embodiment, a slight amount of exhaust gas is circulated at the initial temperature (solid line state in FIG. 16) in the idling state of the engine or the low rotation and low load state, and the valve plate is increased as the temperature rises. When the outer peripheral end of the 17g portion approaches the inner peripheral surface of the main body 17a, the amount of exhaust gas exhausted through the exhaust pipe 13 is gradually reduced, and the open / close valve 17f is fully opened to exhaust a large amount of exhaust gas under high rotation and high load conditions. It can be applied when you want to discharge through.

FIG. 17 shows an eighth embodiment of the present invention, in which the main body 17a and the opening / closing valve 17f in the fifth embodiment (FIG. 14) are straight on the side of the opening / closing valve 17f which is the swing fulcrum. It is the one that is shaped like a swordfish. still,
The shape other than the semi-cylindrical shape may be square or the like.

FIG. 18 shows a ninth embodiment of the present invention, which is a flange 17h of the opening / closing valve 17f in the above embodiment.
Is formed on the upstream side (inside) of the main body 17a. FIG. 19 shows a tenth embodiment of the present invention in which the valve plate 17g of the on-off valve 17f and the flange 17h are formed as separate parts, and the flange 17h is fixed to the valve plate 17g later. is there.

In each of the above embodiments, the valve unit of the present invention is applied to the exhaust pipe in the muffler, but in addition, the muffler is provided with two main and sub outlet pipes.
It may be applied to other exhaust system pipes such as connecting the valve unit of the present invention to the sub outlet pipe.

[0049]

As described above, according to the present invention, when the engine is in the idling state or in the low rotation and low load state, the end of the exhaust pipe is closed or a certain amount of flow area is surely controlled to give priority to noise reduction. Further, when the engine is in a high rotation and high load state, the distribution area of the exhaust pipe can be increased and the function of back pressure reduction priority can be exhibited. Therefore, for example, when the valve unit of the present invention is mounted on the current fixed muffler, there is an effect that the output is extremely low, quieter than the current one at low speed and low load, and equivalent to the current output at high speed and high load.

Since the opening / closing control structure of the opening / closing valve having such a function is a structure in which the opening / closing valve is simply provided with an extension at the end of the exhaust pipe and the connection by the bimetal, Compared with the conventional control by the actuator, the structure is extremely simple and can be manufactured at low cost, and since no control parts are provided outside the muffler, there is no risk of damage to the control parts of the on-off valve due to the external environment such as stepping stones. The protective means is unnecessary, and the silencer capacity can be maximized for the vehicle space.

Further, since the contact interference between the control operating shaft of the on-off valve, the sliding portion, and the parts can be eliminated, the reliability of the on-off valve can be improved and interference noise due to vibration can be prevented.

Further, since the bimetal is used for the opening / closing control, it can be actually used at high temperature as compared with the conventional shape memory alloy. Further, according to the present invention, the main body and the on-off valve are formed as a unit with a component different from the exhaust pipe and are connected to the exhaust pipe, so that the structure of the existing silencer is not modified. The above-mentioned effects can be exhibited by connecting to an ordinary exhaust pipe. Therefore, for example, when the valve unit of the present invention is mounted on the current stationary muffler, there is an effect that the output is extremely low, quieter than the current one at low speed and low load, and equivalent to the current output at high speed and high load.

[Brief description of drawings]

FIG. 1 is a side sectional view of a silencer to which a valve unit according to a first embodiment of the present invention is connected and mounted.

FIG. 2 is a side sectional view showing the valve unit according to the first embodiment of the present invention.

FIG. 3 is a perspective view of the same.

FIG. 4 is a side sectional view of the muffler without the valve unit according to the present invention attached thereto.

FIG. 5 is a side sectional view showing a first example of a connection system.

FIG. 6 is a side sectional view showing a second example of the connection system.

FIG. 7 is a side sectional view showing a third example of the connection system.

FIG. 8 is a side sectional view showing a fourth example of the connection system.

FIG. 9 is a side sectional view showing a fifth example of the connection system.

FIG. 10 is a side sectional view showing a sixth example of the connection system.

FIG. 11 is a side sectional view showing a second embodiment of the present invention.

FIG. 12 is a side sectional view showing a third embodiment of the present invention.

FIG. 13 is a side sectional view showing a fourth embodiment of the present invention.

FIG. 14 is a side sectional view showing a fifth embodiment of the present invention.

FIG. 15 is a sectional side view showing a sixth embodiment of the present invention.

FIG. 16 is a side sectional view showing a seventh embodiment of the present invention.

FIG. 17 is a side sectional view showing an eighth embodiment of the present invention.

FIG. 18 is a side sectional view showing a ninth embodiment of the present invention.

FIG. 19 is a side sectional view showing a tenth embodiment of the present invention.

FIG. 20 is a side sectional view showing a conventional structure.

FIG. 21 is a side sectional view showing the conventional structure at room temperature.

FIG. 22 is a side sectional view showing a state at the same high temperature.

FIG. 23 is a side sectional view showing the same idling state.

FIG. 24 is a side sectional view showing another conventional structure.

[Explanation of symbols]

 13 Exhaust pipe 17a Main body 17b, 17f Open / close valve 17c Extension part 17g Valve plate 17h Tsuba

Claims (2)

[Claims] 1. A plate-shaped on-off valve (17b) is connected to one end of a main body (17a) made of a short pipe, and a part of the valve is connected by a bimetal (19).
9) is provided as a fulcrum so that it can be opened and closed, and the main body (17
An open / close valve (17b) is provided at one end of (a) with a main body (17b).
The opening / closing valve (17) extends from the vertical posture with respect to the axis of (a) to the outside of the main body (17a) by a predetermined angle.
A valve unit for an internal combustion engine, characterized in that an extension (17c) covering the outer periphery of (b) is formed in a projecting manner, and the other end of the main body (17a) is connected to a predetermined exhaust pipe in the exhaust system. 2. An open / close valve (17b) is connected to one end of a main body (17a) made of a short pipe, and a part of the open / close valve (17b) is connected by a bimetal (19) so as to be openable and closable with the bimetal (19) portion as a fulcrum. The on-off valve (17b)
Is a valve plate (17g) and a collar (17h) provided on the outer periphery thereof.
The flange (17h) is formed in the swing range of the valve plate (17g) from room temperature to a predetermined high temperature.
A valve unit in an exhaust system of an internal combustion engine, wherein the valve unit is set to be located in a) and the other end of the main body (17a) is connected to a predetermined exhaust pipe in the exhaust system.