JP2022030976A - Muffler with built-in valve - Google Patents

Abstract

To provide a muffler with a built-in valve in which installation space for a valve can be reduced and which furthermore enables reduction of exhaust sound in a low rotation area of an engine and also enables reduction of exhaust resistance in a high rotation area of the engine.SOLUTION: A muffler 1 with a built-in valve comprises: a separator 3 partitioning inside of a shell 2 into first and second muffler chambers S1, S2; and a valve 9 which is provided in the separator 3 and causes exhaust gas flowing from an inlet pipe 4 into the first muffler chamber S1 to flow through an inner pipe 6 to an outlet pipe 7, and is opened by an exhaust gas pressure of a predetermined value or higher for causing the exhaust gas from the first muffle chamber S1 to flow to the outlet pipe 7 while bypassing the inner pipe 6, the valve 9 including a valve element 9A for opening/closing a bypass passage 3f opened to the outlet pipe 7, a pressure receiving part 9B extending from the valve element 9A and arranged in opposition to the outlet of the inner pipe 6, and a coil spring (energizing means) 10 for energizing the valve element 9A to be closed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a valve built-in silencer having a built-in flow rate sensitive valve that opens and closes according to an exhaust gas flow rate (exhaust gas pressure).

In an internal combustion engine (hereinafter, simply referred to as "engine") that converts heat energy generated by combustion of an air-fuel mixture into kinetic energy, exhaust gas is discharged into the atmosphere via a catalytic converter or a silencer. .. Here, the silencer has a function of reducing the sound (exhaust sound) generated when the exhaust gas is discharged from the engine and adjusting the engine characteristics.

By the way, in a vehicle equipped with an engine as a drive source, it is required to increase the output of the engine in a high speed range in order to improve the performance during acceleration traveling and high-speed traveling. Further, in order to ensure high quietness when idling or traveling at low speed, it is required to reduce the exhaust noise as much as possible. That is, it is required to increase the output of the engine in the high rpm range and suppress the exhaust noise in the low rpm range.

Here, it is known that the engine output and the exhaust noise are greatly affected by the cross-sectional area of the exhaust passage constituting the exhaust system of the engine. Specifically, if the cross-sectional area of the exhaust passage is increased, the engine output can be increased by reducing the exhaust resistance, and conversely, if the cross-sectional area of the exhaust passage is reduced, the exhaust noise is suppressed by increasing the exhaust resistance. On the other hand, it is known that the engine output decreases due to the increase in exhaust resistance.

Therefore, for example, Patent Documents 1 and 2 have proposed a valve-built-in silencer provided with a flow rate-sensitive valve that increases or decreases the cross-sectional area of the exhaust passage according to the exhaust flow rate (exhaust pressure) proportional to the engine rotation speed.

That is, in Patent Document 1, the flow rate sensitive valve built in the silencer is a valve body arranged at the opening end of the silencer in the outlet pipe (exhaust output tube), and a valve that supports the valve body so as to be openable and closable. It has been proposed that the shaft and a flow rate sensing member (pressure receiving member) extending from the valve shaft in the direction opposite to the valve body and arranged at the outlet end of the inlet pipe (exhaust input tube). In this flow rate sensitive valve, the gravity action point of the flow rate sensing member is offset from the valve shaft, and the pressure receiving area of the flow rate sensing member is minimized when the valve is fully closed and gradually increases as the valve opening degree increases. It is set as.

Further, Patent Document 2 proposes a configuration in which a flow rate sensitive valve that opens when the exhaust gas pressure rises beyond a predetermined value is attached to a separator at an opening that is an exhaust gas bypass passage.

Japanese Patent No. 3748313 Japanese Patent No. 4025745

However, in the valve built-in type silencer proposed in Patent Document 1, a configuration is adopted in which the valve body of the flow rate sensitive valve and the valve shaft to which the flow rate sensing member is attached are supported by a shaft support bracket attached to the separator. Therefore, it is necessary to arrange the flow rate sensitive valve away from the separator, and there is a problem that the installation space of the flow rate sensitive valve in the silencer becomes large. Further, since the valve body of the flow rate sensitive valve opens against the direction in which the exhaust gas flows into the outlet pipe, there is a problem that the exhaust resistance becomes large and the engine performance is deteriorated.

In the silencer with a built-in valve proposed in Patent Document 2, a flow rate sensitive valve is attached to the separator, but the valve opens only when the pressure in the silencer chamber partitioned by the separator rises beyond a predetermined value. Exhaust gas that has flowed out to another muffling chamber through this valve and has spread flows into a small-diameter outlet pipe and is discharged into the atmosphere. Therefore, when the valve is opened, the exhaust gas is throttled twice when it passes through the valve and when it flows into the outlet pipe, so that there is a problem that the exhaust resistance becomes large and the engine performance deteriorates.

The present invention has been made in view of the above problems, and an object of the present invention is to keep the installation space of the valve small, to suppress the exhaust noise in the low speed range of the engine in which the valve closes, and to keep the height of the engine in which the valve opens. The purpose of the present invention is to provide a silencer with a built-in valve that can improve engine performance by suppressing exhaust resistance in the rotation range to a small value.

In order to achieve the above object, the invention according to claim 1 divides the inside of the shell into at least the first and second muffling chambers by a separator, and injects the exhaust gas flowing from the inlet pipe into the first muffling chamber. A valve that flows out to the outlet pipe through the pipe and opens a bypass passage by an exhaust gas pressure equal to or higher than a predetermined value to allow the exhaust gas of the first muffling chamber to bypass the inner pipe and flow to the outlet pipe. A valve built-in silencer provided in a separator, wherein the valve has a valve body that opens and closes a bypass passage that opens in the outlet pipe, and a pressure receiving body that extends from the valve body and is arranged to face the outlet of the inner pipe. The first feature is that the portion and the urging means for urging the valve body to the closing side are included.

In the invention according to claim 2, in addition to the first feature, the outlet of the inner pipe opens to the outlet pipe having an inlet opening to the separator, and the pressure receiving portion is from the outlet of the inner pipe. It is arranged on the downstream side in the flow direction of the exhaust gas, and when the valve is in the closed state, a predetermined gap is formed in the flow direction of the exhaust gas between the pressure receiving portion and the outlet of the inner pipe. The second feature is.

In the invention according to claim 3, in addition to the first or second feature, the bypass passage opened and closed by the valve body is formed in the separator, and the bypass passage surrounds the separator. A third aspect is that the outlet pipe is opened by the surrounding portion, and the bypass passage is opened and closed by the valve body so that the first muffling chamber and the outlet pipe are selectively communicated with each other. It is a feature.

In the invention according to claim 4, in addition to the third feature, the surrounding portion is integrally formed with the outlet pipe, and the inlet cross-sectional area of the surrounding portion is the outlet cross-sectional area of the outlet pipe. The fourth feature is that it is set to be larger than.

The fifth feature of the fifth aspect of the present invention is that, in addition to the first to fourth features, the pressure receiving portion is arranged so as to be inclined at a predetermined angle with respect to the bypass passage. And.

According to the sixth aspect of the present invention, in addition to the above-mentioned first to fifth features, the portion of the separator in which the bypass passage is formed constitutes a seating portion on which the valve body is selectively seated. The sixth feature is that the seating portion is inclined with respect to the general surface of the separator.

In the invention according to claim 7, in addition to the feature according to any one of the first to sixth aspects, a part of the separator forms a porous portion provided with a large number of small holes, and the porous portion is formed. The seventh feature is that the first muffling chamber and the second muffling chamber adjacent thereto communicate with each other and the second muffling chamber is filled with a sound absorbing material.

According to the first aspect of the present invention, since the valve is provided in the separator, the installation space of the valve in the silencer can be kept small. Further, since the valve body of the valve opens and closes the bypass passage by the exhaust gas pressure in the first muffling chamber and the exhaust gas pressure acting on the pressure receiving portion, the opening and closing timing of the valve can be adjusted with high accuracy. Performance (flow rate sensitive performance) can be efficiently brought out. Since the opening of the valve changes linearly with the increase and decrease of the exhaust gas pressure by the urging means such as a coil spring, the exhaust noise in the low speed range of the engine is suppressed to a low level to ensure high quietness. It is possible to secure a high engine output by suppressing the exhaust resistance in the high speed range of the engine to a low level.

Here, since the valve body of the valve does not open in the inflow direction of the exhaust gas into the outlet pipe and does not obstruct the inflow of the exhaust gas into the outlet pipe, the flow resistance of the exhaust gas is suppressed to a low level. Further, when the valve is opened in the high rotation range of the engine, the exhaust gas in the first muffling chamber is throttled only once in the bypass passage, so that the exhaust resistance is suppressed to a small value and the decrease in the engine output is also suppressed to a low level.

According to the second aspect of the present invention, when the valve is in the closed state, a predetermined gap is formed between the pressure receiving portion of the valve and the outlet of the inner pipe in the flow direction of the exhaust gas. Exhaust gas flowing out from the outlet of the inner pipe in the low speed range of the engine passes through the gap between the pressure receiving part and the outlet of the inner pipe and flows into the outlet pipe, and the valve is kept closed and the exhaust noise is heard. Is kept low. When the pressure receiving part of the valve receives high exhaust pressure in the high speed range of the engine, the valve body opens the bypass passage and a large amount of exhaust gas bypasses the inner pipe and flows directly to the outlet pipe, resulting in exhaust resistance. It is kept low and the engine output is increased.

According to the invention of claim 3, since the bypass passage formed in the separator is opened to the outlet pipe by the surrounding portion surrounding the bypass passage, the bypass passage is opened from the first muffling chamber when the valve is opened. Exhaust gas flowing into the outlet pipe does not spread to the surroundings, and all of it efficiently flows into the outlet pipe, so that the exhaust resistance in the high speed range of the engine is further suppressed and the engine output is increased.

According to the fourth aspect of the present invention, since the inlet cross-sectional area of the surrounding portion integrally formed with the outlet pipe is set to be larger than the outlet cross-sectional area of the outlet pipe, the adhesion between the outlet pipe and the separator is improved. It can be increased and the number of parts can be reduced.

According to the fifth aspect of the present invention, since the pressure receiving portion of the valve is arranged so as to be inclined at a predetermined angle with respect to the opening, it is easy to set the closed state of the valve and switch from the closed state to the open state. Can be set.

According to the invention of claim 6, since the seating portion where the bypass passage of the separator is formed is inclined with respect to the general surface of the separator, the exhaust gas is straightened to the outlet pipe when the valve is opened. It can flow, the exhaust efficiency is improved, the exhaust resistance is kept low, and the engine output is increased.

According to the invention of claim 7, a part of the exhaust gas that has flowed from the first muffling chamber through the porous portion of the separator to the second muffling chamber is filled in the second muffling chamber. After being absorbed by passing through the sound absorbing material, it passes through the porous portion of the separator, flows into the first sound deadening chamber, and flows into the inner pipe. Since the exhaust gas that has flowed into the second muffling chamber is absorbed by passing through the sound absorbing material, the exhaust sound is effectively suppressed to a low level and the quietness is further improved.

It is a vertical sectional view which shows the basic structure of the valve built-in type silencer which concerns on this invention. It is a perspective view which shows the internal structure of the valve built-in type silencer which concerns on this invention. It is a perspective view which shows the arrangement relation of the separator, the valve, the inner pipe and the outlet pipe of the valve built-in type silencer which concerns on this invention. It is a partial perspective view which shows the closed state of the valve of the valve built-in type silencer which concerns on this invention. It is a partial perspective view which shows the open state of the valve of the valve built-in type silencer which concerns on this invention. It is an exploded perspective view of the valve part of the valve built-in type silencer which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a vertical cross-sectional view showing the basic configuration of the valve built-in silencer according to the present invention, FIG. 2 is a perspective view showing the internal structure of the valve built-in silencer, and FIG. 3 is a separator of the valve built-in silencer. A perspective view showing the arrangement relationship of the valve, the inner pipe and the outlet pipe, FIG. 4 is a partial perspective view showing the closed state of the valve of the silencer with a built-in valve, and FIG. 5 is an open state of the silencer with a built-in valve. FIG. 6 is a partial perspective view showing an exploded perspective view of a valve portion of the silencer with a built-in valve.

The silencer with a built-in valve (hereinafter, simply referred to as “silencer”) 1 according to the present embodiment reduces the sound (exhaust sound) of exhaust gas discharged from an engine which is a drive source of a vehicle, for example, and at the same time, reduces the sound (exhaust sound). It functions to adjust the engine characteristics, and as shown in FIG. 1, it has a hollow container-shaped shell 2. Inside the shell 2, a first muffling chamber S1 is provided by a vertically standing separator 3. It is divided into a second muffling room S2 and a second muffling room S2.

The shell 2 is configured as a monaca-shaped hollow container by fitting the peripheral edges of the openings of the bottomed cup-shaped shell halves 2A and 2B divided into two on the left and right to each other and welding the fitting portions. There is. In the present embodiment, the shell 2 has a left-right two-divided structure, but an upper-bottom two-divided structure may be used. Further, the shell halves 2A and 2B are obtained by press-molding a metal plate such as SUS304 or SUS316L having high heat resistance and corrosion resistance. Here, in the silencer 1, the directions indicated by the arrows in FIGS. 1 and 2 are the "front-back", "left-right", and "up-down" directions, respectively.

Further, as shown in FIG. 1, an inlet pipe 4 penetrates through the lower part of the front end of the shell half body 2B of the shell 2 and is introduced into the first sound deadening chamber S1. Specifically, as shown in FIG. 2, a circular hole 2a is formed in the lower part of the front end of the shell half body 2B on the left side, and the inlet pipe 4 penetrates the circular hole 2a to form a first muffling chamber S1. Has been introduced in.

Here, as shown in FIG. 2, two circular holes 3a, 3b and 3c, 3d are formed at the right end portion and the left end portion of the separator 3, respectively, and the left end of the circular hole 3a of the separator 3 is formed. , A seating portion 3A on which the valve body 9A (see FIGS. 4 to 6) of the valve 9 described later is selectively seated is formed. The portions of the separator 3 except for the two circular holes 3a, 3b and 3c, 3d on the left and right and the periphery of the seating portion 3A are configured as a porous portion (punching metal) in which a large number of circular small holes 3e are formed. Has been done. Therefore, the first muffling chamber S1 and the second muffling chamber S2 in the shell 2 communicate with each other through a large number of small holes 3e formed in the porous portion of the separator 3, and in the present embodiment, the first muffling chamber S1 and the second muffling chamber S2 communicate with each other. As shown in FIG. 1, the second sound deadening chamber S2 is filled with a sound absorbing material (roving material) 5 such as a glass fiber.

By the way, the rear end of the portion introduced into the first sound deadening chamber S1 in the shell 2 of the inlet pipe 4 is inserted into and fixed to the circular hole 3d formed in the left end portion of the separator 3. It is open as an exit to the muffling room S2. Here, a perforated pipe 4A having a large number of circular circular holes 4a is attached to the rear end portion of the inlet pipe 4 near the separator 3. In the present embodiment, the perforated pipe 4A is configured separately from the inlet pipe 4 and connected to the rear end of the inlet pipe 4, but a large number of pipes are connected to the rear end of the inlet pipe 4. The small hole 4a may be directly formed.

Further, as shown in FIGS. 1 to 3, an inner pipe 6 which is bent twice in a U-shape in a side view to form a square ring in a side view is housed in the shell 2. The inner pipe 6 is inserted and fixed in the circular holes 3a, 3b, 3c formed in the separator 3. Specifically, the first horizontal portion 6A at the right end of the inner pipe 6 penetrates the circular hole 3b formed at the right end of the separator 3, and one end thereof is the first muffling chamber in the shell 2. It opens to S1 as an entrance. An enlarged diameter portion 6a is formed at the inlet end of the inner pipe 6.

Then, in the inner pipe 6, the rear end portion of the first horizontal portion 6A is bent at a substantially right angle in the second muffling chamber S2 and extends to the left, and the first vertical portion 6B of the first vertical portion 6B. The second horizontal portion 6C whose left end is bent forward and extends horizontally to the left end portion in the shell 2 and the front end portion of this second horizontal portion 6C are bent at a substantially right angle to turn the first muffling chamber S1 to the right. A second vertical portion 6D extending toward the direction and a third horizontal portion 6E extending horizontally toward the rear are formed by bending the right end of the second vertical portion 6D at a substantially right angle.

Here, as shown in FIGS. 2 and 3, the second horizontal portion 6C of the inner pipe 6 penetrates the circular hole 3c formed at the left end portion of the separator 3 from the second sound deadening chamber S2 in the shell 2. It is introduced into the first muffling chamber S1, and the third horizontal portion 6E is inserted and fixed to the circular hole 3a formed at the right end portion of the separator 3, and the end portion serves as an outlet as described later. It is open to the outlet pipe 7.

Further, as shown in FIGS. 1 and 3, an outlet pipe 7 is attached to the rear surface of the right end portion of the separator 3 via a tapered cylindrical surrounding portion 8, and the entrance of the surrounding portion 8 is the separator 3. It is open to. Here, the outlet pipe 7 is arranged coaxially with the third horizontal portion 3E of the inner pipe 3, and extends horizontally toward the outside of the shell 2 and opens into the atmosphere. Therefore, the outlet of the third horizontal portion 6E of the inner pipe 6 is open to the surrounding portion 8 and is connected to the outlet pipe 7 via the surrounding portion 8.

The surrounding portion 8 is integrally formed with the outlet pipe 7, has a diameter reduced from the separator 3 toward the outlet pipe 7, and its rear end is connected to the outlet pipe 7. Therefore, the inlet cross-sectional area of the surrounding portion 8 is set to be larger than the outlet cross-sectional area of the outlet pipe 7.

By the way, as shown in FIGS. 1 and 2, the seating portion 3A formed on the separator 3 is inclined by a predetermined angle with respect to the vertical general surface of the separator 3 (specifically, from the general surface of the separator 3). (Inclined diagonally downward toward the front), and as shown in FIG. 5, a rectangular hole-shaped bypass passage 3f that opens into the surrounding portion 8 (outlet pipe 7) is formed in the seating portion 3A. ..

Therefore, a valve 9 for opening and closing the bypass passage 3f formed in the seating portion 3A is provided at the portion where the seating portion 3A of the separator 3 is formed. This valve 9 is a flow rate sensitive valve, and is an inner valve body 9A that opens and closes the bypass passage 3f according to the exhaust gas pressure (exhaust gas flow rate), that is, the engine rotation speed, and the inner valve body 9A extending integrally from the valve body 9A. It is configured to include a pressure receiving portion 9B arranged to face the outlet of the third horizontal portion 6E of the pipe 6 and a coil spring 10 as an urging means for urging the valve body 9A to the closing side.

Here, as shown in FIGS. 4 to 6, the valve body 9A is a rectangular plate-shaped member having a flat seating surface 9a formed around it, and a fulcrum bracket 9b standing up at the front end thereof is a separator. By engaging with the inside of the convex portion 3g (see FIG. 6) projecting from the seating portion 3A of 3, the support is rotatably supported up and down around the engagement point of the fulcrum bracket 9b. Further, the central portion of the valve body 9A (a portion other than the surrounding seating surface 9a) constitutes a pressure receiving surface 9c that protrudes in a chevron shape, and a rectangular through hole 9d is formed in the pressure receiving surface 9c. ing.

As shown in FIG. 6, the coil spring 10 is configured by connecting and integrating two left and right coils 10A, and the rectangular locking ring 10a extending from the center of the left and right coils 10A is shown in FIGS. 4 and 5. As shown in the above, the spring retainer 11 is locked in the locking groove 11a of the spring retainer 11 erected in the seating portion 3A of the separator 3. Further, linear engaging bars 10b extend from the left and right coils 10A of the coil spring 10, and these engaging bars 10b are engaged with the lower surfaces of the left and right ends of the valve body 9A, respectively. Therefore, the valve body 9A is constantly urged by the coil spring 10 in the direction of closing the bypass passage 3f (the closing direction of the valve 9).

Further, as shown in FIGS. 3, 4 to 6, a stay-shaped pressure receiving portion 9B extends rearward from the central portion of the valve body 9A of the valve 9 in the width direction, and the pressure receiving portion 9B is integrally extended toward the rear. Is arranged on the downstream side in the flow direction of the exhaust gas (on the right side in FIG. 1) from the outlet of the third horizontal portion 3E of the inner pipe 6 as shown by the solid line in FIG. 1, and when the valve 9 is in the closed state, A predetermined gap δ is formed between the pressure receiving portion 9B and the outlet of the third horizontal portion 3E of the inner pipe 6 in the flow direction of the exhaust gas. Here, the pressure receiving portion 9B is arranged so as to be inclined by a predetermined angle with respect to the bypass passage 3f formed in the seating portion 3A of the separator 3.

Therefore, the bypass passage 3f formed in the seating portion 3A of the separator 3 and the valve 9 provided in the separator 3 are surrounded by the surrounding portion 8. That is, the bypass passage 3f is open in the surrounding portion 8 (that is, the outlet pipe 7), and the valve 9 is housed in the surrounding portion 8.

Next, the operation of the silencer 1 configured as described above will be described.

Exhaust gas discharged from an engine (not shown) is introduced from the inlet pipe 4 to the silencer 1 as shown by an arrow in FIG. That is, a part of the exhaust gas introduced into the inlet pipe 4 flows into the first muffling chamber S1 from a large number of small holes 4a formed in the perforated pipe 4A, and the inner pipe 6 from the first muffling chamber S1. Inflow to. Then, the exhaust gas flowing into the inner pipe 6 directs the first horizontal portion 6A, the first vertical portion 6B, the second horizontal portion 6C, the second vertical portion 6D, and the third horizontal portion 6E of the inner pipe 6. It flows sequentially while changing, flows from the outlet of the third horizontal portion 6E to the outlet pipe 7 via the surrounding portion 8, and is finally discharged into the atmosphere.

Here, in the low rotation range where the engine rotation speed is equal to or less than the set value, the total of each pressing force due to the exhaust gas pressure acting on the pressure receiving surface 9c and the pressure receiving portion 9B of the valve 9 is larger than the urging force of the coil spring 10. When it is small, as shown by the solid line in FIG. 1 and FIG. 4, the valve 9 is in the closed state, and the valve body 9A of the valve 9 closes the bypass passage 3f formed in the seating portion 3A of the separator 3. There is. Therefore, the exhaust gas of the first muffling chamber S1 does not flow to the outlet pipe through the bypass passage 3f, and the exhaust gas flowing out from the outlet of the third horizontal portion 6E of the inner pipe 6 is the third horizontal portion. It flows into the surrounding portion 8 through the gap δ formed between the outlet of 6E and the pressure receiving portion 9B of the valve 9, and is discharged to the atmosphere through the outlet pipe 7.

Further, the other part of the exhaust gas flowing through the inlet pipe 4 and the part of the exhaust gas flowing from the small hole 4a of the perforated pipe 4A into the first sound deadening chamber S1 are the outlet of the inlet pipe 4 and the perforated separator 3. Sound is absorbed by flowing into the second sound deadening chamber S2 from a large number of small holes 3e formed in the portion and passing through the sound deadening material 5 filled in the second sound deadening chamber S2. Then, the exhaust gas absorbed by the sound deadening material 5 passes through the small holes 3e formed in the porous portion of the separator 3 and flows into the first sound deadening chamber S1 from the first sound deadening chamber S1 to the inner pipe 6. It flows in and is finally discharged into the atmosphere via the same route as described above.

As described above, when the engine speed is in the low speed range, the exhaust gas pressure is relatively low, and the exhaust gas flow rate is small, the exhaust gas repeatedly expands and contracts in the shell 2 of the silencer 1. As the noise energy is attenuated, the sound is absorbed by the sound absorbing material 5, so that the exhaust noise is suppressed to a low level and the noise is reduced.

On the other hand, when the engine rotation speed is in the high rotation range exceeding a predetermined value, both the pressure and the flow rate of the exhaust gas discharged from the engine are large, and the exhaust gas acting on the pressure receiving surface 9c and the pressure receiving portion 9B of the valve 9, respectively. When the sum of the pressing forces due to the pressure exceeds the urging force of the coil spring 10, the valve 9 opens the bypass passage 3f formed in the seating portion 3A of the separator 3. Specifically, as shown in the chain line of FIG. 1 and FIG. 5, the valve body 9A of the valve 9 rotates clockwise around the engagement point of the fulcrum bracket 9b against the urging force of the coil spring 10. Open the bypass passage 3f.

When the bypass passage 3f is opened as described above, the first muffling chamber S1 and the outlet pipe 7 communicate with each other via the surrounding portion 8, so that a part of the exhaust gas flowing into the first muffling chamber S1 is released. As shown by the broken line arrow in FIG. 1, the flow flows from the bypass passage 3f to the outlet pipe 7 via the surrounding portion 8 by bypassing the inner pipe 6. That is, when the engine rotation speed is in the high rotation range and the flow rate (pressure) of the exhaust gas discharged from the engine is large, the exhaust gas flowing from the inlet pipe 4 to the first muffling chamber S1 is an inner. It is discharged into the atmosphere via a path leading to the outlet pipe 7 via the pipe 6 and a path directly reaching the outlet pipe 7 by bypassing the inner pipe 6. Therefore, when the engine speed is in the high speed range, a large amount of exhaust gas flows smoothly in the shell 2 of the silencer 1, so that the flow resistance of the exhaust gas is suppressed to a low level and the engine output is increased.

As described above, in the silencer 1 according to the present embodiment, since the valve 9 is provided in the separator 3, the installation space of the valve 9 in the silencer 1 can be suppressed to a small size. Further, since the valve body 9A of the valve 9 opens and closes the bypass passage 3f by the exhaust gas pressure in the first muffling chamber S1 and the exhaust gas pressure acting on the pressure receiving portion 9B, the opening / closing timing of the valve 9 is adjusted with high accuracy. It is possible to efficiently bring out the performance (flow rate sensitive performance) of the valve 9. Here, since the opening degree of the valve 9 changes linearly with the increase and decrease of the exhaust gas pressure by the coil spring 10 which is an urging means, the exhaust noise in the low speed range of the engine is suppressed to a low level and high quietness is achieved. At the same time, it is possible to secure high engine output by suppressing the exhaust resistance in the high speed range of the engine to a low level.

Further, since the valve body 9A of the valve 9 opens in the inflow direction of the exhaust gas into the outlet pipe 7 and does not obstruct the inflow of the exhaust gas into the outlet pipe 7, the flow resistance of the exhaust gas is suppressed to a low level. Then, when the valve 9 is opened in the high rotation range of the engine, the exhaust gas of the first muffling chamber S1 is throttled only once in the bypass passage 3f, so that the exhaust resistance is suppressed to a small value and the decrease in the engine output is also suppressed to a low level. Will be.

Further, in the present embodiment, when the valve 9 is in the closed state, a predetermined gap δ (see FIG. 1) is provided between the pressure receiving portion 9B of the valve 9 and the outlet of the inner pipe 6 in the flow direction of the exhaust gas. ) Is formed, so that the exhaust gas flowing out from the outlet of the inner pipe 6 in the low rotation range of the engine passes through the gap δ between the pressure receiving portion 9B of the valve 9 and the outlet of the inner pipe 6 and passes through the outlet pipe. The gas flows into the valve 9, the closed state of the valve 9 is maintained, and the exhaust noise is suppressed to a low level. Then, when the pressure receiving portion 9B of the valve 9 receives a high exhaust pressure in the high rotation range of the engine, the valve body 9A opens the bypass passage 3f, and a large amount of exhaust gas bypasses the inner pipe 6 and directly to the outlet pipe 7. Since it flows, the exhaust resistance is kept low and the engine output is increased.

Further, in the present embodiment, the bypass passage 3f formed in the seating portion 3A of the separator 3 is opened to the outlet pipe 7 by the surrounding portion 8 surrounding the bypass passage 3f, so that when the valve 9 is opened. Exhaust gas flowing into the outlet pipe 7 from the first muffling chamber S1 does not spread to the surroundings, and all of the exhaust gas efficiently flows into the outlet pipe 7. Therefore, the exhaust resistance in the high speed range of the engine is further suppressed and the engine output is increased.

Further, in the present embodiment, since the inlet cross-sectional area of the surrounding portion 8 integrally formed with the outlet pipe 7 is set to be larger than the outlet cross-sectional area of the outlet pipe 7, the outlet pipe 7 and the separator 3 are combined. Adhesion can be improved and the number of parts can be reduced.

Further, since the pressure receiving portion 9B of the valve 9 is arranged so as to be inclined by a predetermined angle with respect to the bypass passage 3f, it is possible to easily set the closed state of the valve 9 and the switching from the closed state to the open state. can. Further, since the seating portion 3A on which the bypass passage 3f of the separator 3 is formed is inclined with respect to the general surface of the separator 3, the exhaust gas may flow straight to the outlet pipe 7 when the valve 9 is opened. can. Therefore, the exhaust efficiency is improved, the exhaust resistance is suppressed to a low level, and the engine output is increased.

Although the present invention has been described above with respect to the valve built-in type silencer 1 in which the inside of the shell 2 is partitioned into two silence chambers S1 and S2 by one separator 3, the present invention describes the present invention. The same applies to a silencer with a built-in valve in which the inside of the shell is divided into three or more silence chambers by two or more separators.

Further, the present invention can be similarly applied to any other valve built-in type silencer having an internal structure different from the internal structure of the valve built-in type silencer in the above embodiment.

Further, although the present invention has been described above with respect to a form in which the present invention is applied to a silencer with a built-in valve for reducing the sound (exhaust sound) of exhaust gas discharged from the engine of a vehicle, the present invention has a form other than the engine. It can also be applied to a silencer with a built-in valve for reducing the noise (exhaust noise) of exhaust gas discharged from any device.

In addition, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of claims and the technical ideas described in the specification and drawings. Of course.

1 Valve built-in silencer 2 Shell 3 Separator 3A Separator seating part 3f Separator bypass passage 4 Inlet pipe 5 Sound absorbing material 6 Inner pipe 7 Outlet pipe 8 Surrounding part 9 Valve 9A Valve valve body 9B Valve pressure receiving part 10 Coil spring (Means of urging)
S1 1st anechoic chamber S2 2nd anechoic chamber δ Gap between inner pipe outlet and valve pressure receiving part

Claims (7)

The inside of the shell is divided into at least the first and second muffling chambers by a separator, and the exhaust gas flowing from the inlet pipe into the first muffling chamber is discharged to the outlet pipe through the inner pipe and exhaust of a predetermined value or more. A valve-built-in silencer having a valve provided in the separator for opening a bypass passage by gas pressure and allowing the exhaust gas of the first muffling chamber to bypass the inner pipe and flow to the outlet pipe.
The valve is
A valve body that opens and closes the bypass passage that opens in the outlet pipe,
A pressure receiving portion extending from the valve body and arranged to face the outlet of the inner pipe,
A valve built-in type silencer including a urging means for urging the valve body to the closed side. The outlet of the inner pipe opens to the outlet pipe whose inlet opens to the separator.
The pressure receiving portion is arranged on the downstream side in the exhaust gas flow direction from the outlet of the inner pipe, and when the valve is in the closed state, the exhaust gas flow direction is between the pressure receiving portion and the outlet of the inner pipe. The silencer with a built-in valve according to claim 1, wherein a predetermined gap is formed in the silencer. The bypass passage opened and closed by the valve body is formed in the separator, the bypass passage is opened to the outlet pipe by a surrounding portion surrounding the bypass passage, and the bypass passage is opened and closed by the valve body. The valve built-in type silencer according to claim 1 or 2, wherein the first silencer chamber and the outlet pipe are configured to selectively communicate with each other. The third aspect of the present invention, wherein the surrounding portion is integrally formed with the outlet pipe, and the inlet cross-sectional area of the surrounding portion is set to be larger than the outlet cross-sectional area of the outlet pipe. Silent with built-in valve. The valve built-in type silencer according to any one of claims 1 to 4, wherein the pressure receiving portion is arranged so as to be inclined at a predetermined angle with respect to the bypass passage. The portion of the separator in which the bypass passage is formed constitutes a seating portion on which the valve body is selectively seated, and the seating portion is characterized in that the seating portion is inclined with respect to the general surface of the separator. The silencer with a built-in valve according to any one of claims 1 to 5. A part of the separator forms a porous portion provided with a large number of small holes, and the first muffling chamber and the second muffling chamber adjacent thereto communicate with each other through the porous portion. The valve built-in type silencer according to any one of claims 1 to 6, wherein the second silencer chamber is filled with a sound absorbing material.

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