WO2008150024A1

WO2008150024A1 - Silencer

Info

Publication number: WO2008150024A1
Application number: PCT/JP2008/060730
Authority: WO
Inventors: Youhei Toyoshima
Original assignee: Calsonic Kansei Corporation
Priority date: 2007-06-06
Filing date: 2008-06-05
Publication date: 2008-12-11

Abstract

A silencer exhibiting excellent silence characteristics for damping the delivery sound over a wide range including the entire region of low frequency zone, intermediate frequency zone, and high frequency zone without increasing the muffler volume. In the silencer (1) where the inside space of a muffler shell (2) is partitioned into a first chamber (3) and a second chamber (4) and a control valve (14) opening/closing freely depending on the flow rate of exhaust gas is fixed to the outlet portion (6b) of an inlet pipe (6) by means of a torsion coil spring (15), the second chamber (4) is changed to a low frequency resonator chamber for dampingthe delivery sound in the low frequency zone, an intermediate frequency resonator chamber for damping the delivery sound in the intermediate frequency zone, and an expansion chamber for damping the delivery sound in the high frequency zone by varying the opening of the control valve (14) stepwise.

Description

Paper erase Technical field

The present invention relates to a silencer for reducing noise generated from an exhaust system of an automobile or the like. Background art

In Japanese Patent Laid-Open No. 2000-0 9 2 5 6, in a muffler for automobiles, in order to reduce exhaust noise, exhaust pressure (at the open end of the inner pipe provided in the muffler shell) Proposed with a control valve that opens and closes at the flow rate of the exhaust gas)

Disclosure of the invention

In the technique described in the above document, even if the flow path is controlled by a single control valve, it is acoustically ON (ON)-OFF (OFF) control, and there is a limit to finely control the silencing characteristics. .

In addition, even if the control with a single control valve is based on the silencing characteristics, it has been sufficient in terms of characteristics in the past, but in recent years there has been an increasing demand for further improvements in silencing and pressure loss performance. .

The reason for this is that the demand for quietness in the passenger compartment has become more stringent, and that hybrid vehicles that achieve optimal driving with both engines and motors have become popular. Hybrid vehicles have a quieter running sound than conventional vehicles. The demand for noise reduction for air noise is becoming stricter.

Therefore, when an internal exhaust system that has not been a problem in the past is applied to a hybrid vehicle, the noise contribution ratio of the exhaust system increases, and a reduction in exhaust noise is required. In this way, the low noise noise needs of the air system are becoming higher than before, but it is difficult to increase the muffler capacity further due to the vehicle layout (the noise can be reduced by increasing the muffler capacity) )

In such a situation, the present invention can attenuate the discharge sound over a wide range of low frequency, medium frequency and high frequency without increasing the muffler volume in order to solve the above-described problems. An object of the present invention is to provide a silencer having excellent silencing characteristics. A muffler according to an aspect of the present invention includes a cylindrical muffler shell, a kaffle that divides the inner space of the muffler shell into a first chamber and a second chamber, and a first small hole at a position corresponding to the first chamber. And having an outlet portion in the second chamber, an inlet pipe for introducing exhaust gas into the muffler shell, an intermediate pipe fixed to the baffle and communicating between the first chamber and the second chamber, and silenced in the muffler shell The first outlet pipe that discharges the exhaust gas to the outside and the second chamber are the low frequency type resonator chamber that attenuates the discharge sound in the low frequency range, the medium frequency type resonator chamber that attenuates the discharge sound of the medium frequency, and the high frequency A low noise structure that changes to an expansion room that attenuates the discharge sound of the area.

According to the silencer according to one aspect of the present invention, the muffler volume is increased by changing the second chamber into the low frequency type resonator chamber, the medium frequency type resonator chamber, and the expansion chamber by the noise reduction mechanism. It is possible to attenuate the discharge sound of a wide range of frequencies without hesitation. Brief Description of Drawings

FIG. 1 is a cross-sectional view of the silencer of the first embodiment. FIG. 2 (A) is an enlarged vertical cross-sectional view of the main part of the part where the control valve is provided. Figure 2 (

B) is an enlarged cross-sectional view of a main part of a portion where a control valve is provided.

Fig. 3 is a characteristic diagram showing the relationship between the valve position and the discharge sound level.

Fig. 4 (A) shows the flow of exhaust gas when the control valve is closed and the second chamber is a low-frequency resonator chamber. FIG. 4 (B) is a diagram showing the flow of exhaust gas when the control valve is slightly opened and the second chamber is used as an intermediate frequency resonator chamber. Fig. 4 (

C) is a diagram showing the flow of exhaust gas when the control valve is opened and the second chamber is used as an expansion chamber.

FIG. 5 is a cross-sectional view of the silencer of the second embodiment.

FIG. 6 is a cross-sectional view of the silencer of the third embodiment.

FIG. 7 (A) is a diagram showing the flow of exhaust gas when both the first and second control valves are closed and the second chamber is a low frequency type resonator chamber. FIG. 7 (B) is a diagram showing the flow of exhaust gas when the first control valve is opened, the second control valve is closed, and the second chamber is used as an intermediate frequency resonator chamber. FIG. 7 (C) is a diagram showing the flow of exhaust gas when both the first and second control valves are opened and the second chamber is used as an expansion chamber.

FIG. 8 is a cross-sectional view of the silencer of the fourth embodiment.

FIG. 9 is a cross-sectional view of the silencer of the fifth embodiment.

FIG. 10 (A) is a diagram showing the flow of exhaust gas when the control valve is closed and the second chamber is used as a low-frequency resonator chamber. FIG. 10 (B) is a diagram showing the flow of exhaust gas when the control valve is slightly opened and the second chamber is used as a medium frequency type resonator chamber. FIG. 10 (C) is a diagram showing the flow of exhaust gas when the control valve is opened and the second chamber is used as the expansion chamber.

FIG. 11 is a cross-sectional view of the silencer of the sixth embodiment.

FIG. 12 is a cross-sectional view of the silencer of the seventh embodiment. FIG. 13 (A) is an enlarged vertical cross-sectional view of the main part of the portion where the control valve of the seventh embodiment is provided. FIG. 13 (B) is an enlarged cross-sectional view of the main part of the portion where the control valve of the seventh embodiment is provided.

FIG. 14 (A) is a diagram showing the flow of gas when the control valve of the seventh embodiment is closed and the second chamber is a low-frequency resonator chamber. FIG. 14 (B) is a diagram showing the flow of exhaust gas when the control valve of the seventh embodiment is slightly opened and the second chamber is used as a medium frequency type resonator chamber. FIG. 14 (C) is a diagram showing the flow of exhaust gas when the control valve of the seventh embodiment is opened and the second chamber is used as an expansion chamber.

FIG. 15 is a cross-sectional view of the silencer of the eighth embodiment.

FIG. 16 is a cross-sectional view of the silencer of the ninth embodiment.

FIG. 17 is a cross-sectional view of the silencer of the 10th embodiment.

FIG. 18 (A) is an enlarged vertical sectional view of a main part of a portion where the control valve of the first embodiment is provided. FIG. 18 (B) is an enlarged cross-sectional view of the main part of the portion where the control valve of the first embodiment is provided. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

"First embodiment"

Fig. 1 is a cross-sectional view of the silencer of the first embodiment, Fig. 2 (A) is an enlarged vertical cross-sectional view of the main part where the control valve is provided, and Fig. 2 (B) is a main part of the part where the control valve is provided. Fig. 3 is a characteristic diagram showing the relationship between the valve position and the discharge sound level. Fig. 4 (A) shows the flow of exhaust gas when the control valve is closed and the second chamber is used as the low-frequency resonator chamber. Fig. 4 (B) shows a slightly open control valve and the second chamber in the medium frequency type resonator. FIG. 4 (C) is a diagram showing the flow of exhaust gas when the control valve is opened and the second chamber is used as an expansion chamber.

As shown in FIG. 1, a silencer (muffler) 1 according to the first embodiment includes a cylindrical muffler shell 2 and a buff nozzle 5 that partitions the inner space of the muffler shell 2 into a first chamber 3 and a second chamber 4. An inlet pipe 6 for introducing exhaust gas into the muffler shell 2, an intermediate pipe 7 for communicating the first chamber 3 and the second chamber 4, and a first outlet for discharging the exhaust gas silenced in the muffler shell 2 to the outside Pipe 8 and second outlet pipe 1 3 and second chamber 4 are divided into a low-frequency resonator chamber that attenuates low-frequency discharge sound, a medium-frequency resonator chamber that attenuates medium-frequency discharge sound, and a high frequency. And a low noise structure 9 that changes into an expansion room that attenuates the discharge sound in the area.

The interior of the muffler 2 is divided into two chambers, a first chamber 3 and a second chamber 4, by a baffle 5. The first chamber 3 is provided on the inlet side where the inlet pipe 6 is provided. The second chamber 4 is provided on the outlet side where the first outlet pipe 8 is provided.

The inlet pipe 6 is provided through the front end plate 10 of the muffler shell 2. Then, the inlet portion 6a of the inlet pipe 6 is opened to the outside of the muffler casing 2 and communicated with an engine (not shown) which is a sound source, and the outlet portion 6b passes through the baffle 5 and enters the second chamber 4. Is open. A first small hole 11 is formed in the inlet pipe 6 at a position corresponding to the first chamber 3.

The intermediate pipe 7 is provided through a baffle 5 that partitions the first chamber 3 and the second chamber 4, and is supported by the baffle 5. The intermediate pipe 7 has one end portion 7 a opened in the first chamber 3 and the other end portion 7 b opened in the second chamber 4.

The first outlet pipe 8 is provided through the rear end plate 12 2 and the baffle 5 of the muffler shell 2. It is supported. The first outlet pipe 8 has an inlet portion 8 a opened in the first chamber 3 and an outlet portion 8 b opened outside the muffler shell 2.

The second outlet pipe 13 is connected to the outlet portion 6 b of the inlet pipe 6 by connecting the inlet portion 13 a. The second outlet pipe 13 is provided through the rear end plate 12 2 and opens the outlet portion 13 b to the outside of the muffler shell 2. In addition, the second outlet pipe 13 has a larger diameter than the first outlet pipe 8.

Low noise, structure 9 is provided at the connection portion with the second outlet pipe 13 connected to the outlet portion 6 b of the inlet pipe 6 in the second chamber 4, and the exhaust gas flowing through the inlet pipe 6 A control valve 14 that opens and closes the outlet portion 6 b of the inlet pipe 6 according to the gas flow rate, a variable opening mechanism 15 that changes the opening degree of the control valve 14 stepwise, and a control valve 1 4 The second small hole 16 formed in the second outlet pipe 13 for allowing the exhaust gas to flow into the second chamber 4 according to the opening position of the second small hole 16 and force.

The control valve 14 is formed as an opening / closing lid that closes the opening of the outlet portion 6b of the inlet pipe 6, and the inlet pipe is opened and closed with an upper end portion as a fulcrum by a hinge mechanism (not shown). It is attached to the connection between 6 and the second outlet pipe 13.

The opening variable mechanism 15 is, for example, a coil panel, and the panel locking portion 15 a of the coin panel is locked and fixed to the control valve 14. The opening variable mechanism 15 is always urged in the direction to close the control valve 14 by the spring force of the coil panel, but according to the gas flow rate of the exhaust gas flowing through the inlet pipe 6 (exhaust pressure In response to change) Release control valve 14.

The second small hole 16 formed in the second outlet pipe 13 is formed at a position corresponding to the rotation range of the control valve 14. From this second small hole 1 6 the control valve 1 Exhaust gas flows into the second chamber 4 through the inlet pipe 6 only when it is opened to a certain angle.

The opening variable mechanism 15 changes the opening of the control valve 14 step by step. The step of opening the control valve 14 is based on the following experimental data. FIG. 3 is a characteristic diagram showing the relationship between the valve position of the control valve 14 and the discharge sound level. The middle line A (solid line) in Fig. 3 is a graph when the control valve 14 is in the closed position A as shown in Fig. 2 (A), and the line B (dashed line) is controlled as shown in Fig. 2 (A). Graph when valve 14 is in position B opened to the position where the second small hole 16 is released, line C is in position C where control valve 14 is widely open as shown in Fig. 2 (A) It is a graph of time.

From this characteristic chart, the engine speed is about 0 to: In the low frequency range below 1 00 0 0, the discharge sound is the lowest when the control valve 14 is in the closed position A, and the engine speed is about 1 0 0 0 to 4 0 0 0 In the middle frequency range of rotation, when the control valve 14 is in the position B opened to the position where the second small hole 16 is released, the discharge sound is the lowest, and the engine speed is In the high frequency range of about 400 to 70,000, the discharge sound is the lowest when the control valve 14 is at the position C where the valve 14 is greatly opened.

Based on the results of this experiment, the control valve 14 is set to a position A where the exhaust gas discharge sound frequency level is close to the outlet portion 6 b of the inlet pipe 6 in the low frequency range, and the second small hole in the middle frequency range. 1 Set the panel constant of the opening variable mechanism 15 to a position B where the opening 6 is to be released and set the outlet portion 6b to a position C where the outlet 6b is wide open in the high frequency range. Control the opening state.

Next, the silencing effect of the silencer 1 configured as described above will be described with reference to FIG.

If the engine speed is low (approx. 0 to 1 0 0 0), the control valve 1 is used when the flow rate of exhaust gas flowing into the inlet pipe 6 is small (when the exhaust pressure is low). As shown in FIG. 4 (A), the panel force of the opening variable mechanism 15 which is a coil spring that urges the control valve 14 4 is superior to the exhaust pressure, and the outlet portion 6 b of the inlet pipe 6 Block.

If the outlet portion 6 b of the inlet pipe 6 is blocked by the control valve 14, the exhaust gas and the exhaust sound flow out from the first small hole 11 formed in the inlet pipe 6 to the first chamber 3. At this time, the first chamber 3 acts as an expansion chamber, and the control valve 14 is closed, so that the second chamber 4 is discharged from the outlet portion 8b through the first outlet pipe 8. Is connected to the first chamber 3 only by the intermediate pipe 7 and functions as a low-frequency resonator chamber that attenuates the discharge sound in the low-frequency range. The resonator room is adopted for the purpose of attenuation in the low frequency range. If noise such as the muffled noise in the vehicle interior and the running noise cannot be completely silenced, the resonator room will attenuate the specific frequency. In this case, the attenuation frequency is determined by the diameter and length that determine the conductivity of the intermediate pipe 7 only (the ease of sound entry), so the attenuation frequency is also the capacity of the second chamber 4 However, it becomes a low-frequency resonator and starts running, and the low-frequency como sound can be significantly attenuated.

If the engine speed increases (as a guideline, about 1 0 0 0 to 4 0 0 0), and the exhaust gas flow into the inlet pipe 6 increases (if the exhaust pressure increases), the control valve 1 As shown in FIG. 4 (B), 4 is formed in the second outlet pipe 13 against the panel force of the opening variable mechanism 15 which is a coil spring for urging the control valve 14. Open the second small hole 16 to the position where it should be released. However, the opening position of this control valve 14 is the position where air gas and exhaust sound are not discharged from the outlet portion 1 3 b of the second outlet pipe 1 3 (however, the opening ratio of the valve portion is Even if it is not zero, if the hole area ratio is as small as 7% or less, there is an effect as a medium frequency resonator). As a result, the exhaust gas and the exhaust noise are discharged from the second small hole 16 formed in the second outlet pipe 13 into the second chamber 4. At this time, the second chamber 4 includes the conductivity of the second small hole 16 and the resonator pipe (the portion of the inlet pipe 6 facing the second chamber 4 from the rear of the small hole 11) and the conductive of the intermediate pipe 7. Attenuates a slightly higher frequency, which is a combined frequency. That is, the second chamber 4 functions as a medium frequency resonator chamber that attenuates the discharge sound in the medium frequency range. The exhaust gas discharged to the second chamber 4 is discharged to the first chamber 3 through the intermediate pipe 7 and then discharged to the outside of the muffler shell 2 through the first outlet pipe 8.

If the engine speed becomes higher (as a guideline, about 400 to 700 rpm), if the exhaust gas flow into the inlet pipe 6 further increases (if the exhaust pressure further increases) As shown in FIG. 4 (C), the control valve 14 opens largely against the panel force of the opening variable mechanism 15 which is a coil panel that urges the control valve 14. As a result, air gas and exhaust noise are discharged from the outlet portion 13 b of the second outlet pipe 13 to the outside of the muffler shell 2. At this time, the second chamber 4 changes from the middle frequency type resonator chamber to the expansion chamber, and attenuates a wide frequency range from the middle frequency to the high frequency range. The expansion chamber plays a role of silencing through the small hole 11 of the inlet pipe 6, expansion from the intermediate pipe 7 to the second chamber, and contraction to the outlet pipe 13. In this way, it is possible to mute the low frequency range to the high frequency range in one room according to changes in the exhaust gas flow rate.

As described above, it is necessary to set the panel constant of the coil panel that is the opening variable mechanism 15 so that the opening of the control valve 14 can be changed (controlled). According to the silencer 1 configured as described above, the two tail tubes exiting from the muffler shell 2 are connected to the outlet of the second outlet pipe 1 3 to which the control valve 1 4 is attached. While the diameter is increased, the diameter of the first outlet pipe 8 without the control valve 1 4 is set to be narrow, so when the control valve 14 is closed and the flow rate is low, the first outlet pipe 8 is thin. Since exhaust noise is discharged from the outlet pipe, the silencing effect from low to medium frequency is increased, and there is no increase in pressure loss because the flow rate is small.

Further, according to the silencer 1, when the exhaust gas flow rate is high, the force control valve 14 is opened to increase the contribution rate of the air flow noise, and the gas discharge area is increased, so that the pipe diameter is increased. The in-pipe flow velocity of the large second outlet pipe 1 3 also decreases, and problems such as an increase in airflow noise level and an increase in pressure loss level are solved.

Further, according to the silencer 1, the noise reduction mechanism 9 changes the second chamber 4 into a low frequency ¾ resonator room, a medium frequency ¾M resonator room, and an expansion chamber without increasing the muffler volume. It is possible to attenuate the discharge sound in a wide range of frequencies.

Further, according to the silencer 1, the control valve 14 can be opened and closed in stages by opening and closing the control valve 14 with the opening degree variable mechanism 15 according to the gas flow rate of the exhaust gas. The discharge sound in the targeted frequency band can be attenuated.

In addition, according to the silencer 1, since the control valve 14 is not opened and closed by using an actuator, but the control valve 14 is controlled to be opened by exhaust gas exhaust pressure, the cost of the apparatus is reduced. It can be simplified.

In addition, according to the silencer 1, a muffler structure using a single baffle 5 is used, and since a single control valve 14 is not used, a heavy * if is not added. In addition, according to the silencer 1, when using an actuator as in the conventional structure to achieve the same performance as a muffler that allows the control valve 14 to be opened and closed, the muffler capacity is 20-30% lower than that of the conventional structure. It can be downsized.

"Second Embodiment" FIG. 5 is a cross-sectional view of the silencer of the second embodiment. In the second embodiment, the structure of the noise reduction mechanism 9 comprising the control valve 14, the opening variable mechanism 15 and the second small hole 16 is the same as that of the first embodiment. The intermediate pipe 7 and the first outlet pipe 8 are connected by a substantially U-shaped pipe 17.

In this way, when the intermediate pipe 7 and the first outlet pipe 8 are connected by the substantially U-shaped pipe 17, the tail tube with a narrow pipe diameter becomes a so-called U-turn tube, and the muffler of low frequency to medium frequency is suppressed. The effect can be increased.

When this U-turn tube is lengthened, there is a phenomenon of tail tube resonance that is determined from the tube length, so a small hole 18 is opened at a site corresponding to the first chamber 3. By forming the small holes 18, the tail tube resonance phenomenon can be suppressed. As described above, the silencer 1 of the second embodiment has a structure in which the effect of the U-turn long tail is substantially utilized, but the influence is suppressed by dividing the tail tube resonance. In the silencer 1 of the first embodiment, if there is a concern about tail tube resonance due to the length of the first outlet pipe 8 in FIG. A small hole may be opened.

Further, according to the silencer 1 of the second embodiment, when the second chamber 4 is closed, the exhaust gas and the exhaust noise are discharged into the first chamber 3 from the first small hole 11 of the inlet pipe 6. Then, it flows into the inside of the first outlet pipe 8 from the small hole 18, but in this case, since the flow rate is small, the influence on the pressure loss and the air flow noise becomes small.

As described above, the conventional resonator structure attenuates the fixed frequency in the specific rotation speed range and is an unnecessary room in the other rotation speed ranges, but in the silencer 1 of the first and second embodiments, Because it changes in stages (in this example, 3 stages) according to the engine speed (gas flow rate of exhaust gas), it is necessary to attenuate the discharge sound in a wide frequency band such as low frequency, medium frequency, and high frequency. Can do. `` Third embodiment ''

Fig. 6 is a cross-sectional view of the silencer of the third embodiment, and Fig. 7 (A) shows the flow of exhaust gas when both the first and second control valves are closed and the second chamber is a low-frequency ¾M resonator chamber. Fig. 7 (B) is a diagram showing the flow of exhaust gas when the first control valve is opened and the second control valve is closed to make the second chamber a medium frequency ¾M resonator chamber, and Fig. 7 (C) is a diagram FIG. 6 is a diagram showing the flow of exhaust gas when both the first and second control valves are opened and the second chamber is an expansion chamber.

In the silencer 1 of the third embodiment, unlike the first embodiment, the second outlet pipe 13 is made independent of the inlet pipe 6 and provided on the extension line of the inlet pipe 6, and the second outlet The second control valve 19 is provided at the inlet portion 1 3 a of the pipe 1 3. The control valve provided at the outlet portion 6b of the inlet pipe 6 is referred to as a first control valve 14 in the third embodiment.

As in the first embodiment, the first control valve 14 and the second control valve 19 are both connected to the inlet pipe 6 by the first opening variable mechanism 15 and the second opening variable mechanism 20 made of a coil panel. The outlet portion 6 b and the inlet portion 13 a of the second outlet pipe 13 are configured to change the opening stepwise according to the gas flow rate of the exhaust gas. In the third embodiment, the first and second control valves 14 and 19 are in two stages: a position where the opening is closed and a position where the opening is opened.

Since the silencer 1 of the third embodiment has the same configuration as that of the first embodiment except for the above-described differences, the description of the same components is omitted.

Next, the silencing action by the silencer 1 of the third embodiment will be described with reference to FIG.

If the engine speed is low (approx. 0 to 100 rpm as a guideline), if the exhaust gas flowing into the inlet pipe 6 is small (if the exhaust pressure is low), the first control valve 7 (A), the panel force of the first opening variable mechanism 15 which is a coil panel for energizing the first control valve 14 is superior to the exhaust pressure, as shown in FIG. Block 6 outlet 6 b.

If the outlet portion 6 b of the inlet pipe 6 is blocked by the control valve 14, the exhaust gas and the exhaust sound flow out from the first small hole 11 formed in the inlet pipe 6 to the first chamber 3. At this time, the first control valve 14 and the second control valve 19 are closed, so that the second chamber 4 is It functions as a low-frequency resonator room that attenuates low-frequency discharge sound. In this case, the attenuation frequency of the resonator chamber is determined by the conductivity of the intermediate pipe 7 alone, so the attenuation frequency depends on the capacity of the second chamber 4, but it becomes a low-frequency resonator, and the low frequency «como Can be greatly attenuated.

If the engine speed becomes higher (as a guideline, about 1 0 0 0 to 4 0 0 0), if the flow rate of the exhaust gas flowing into the inlet pipe 6 increases (if the exhaust pressure increases), the first control As shown in FIG. 7 (B), the valve 14 is piled on the panel force of the first opening variable mechanism 15 that is a coil spring that urges the first control valve 14, and the outlet portion of the inlet pipe 6 6 Open b. On the other hand, the second control valve 19 has an inlet portion 1 3 a of the second outlet pipe 1 3 in order to overcome the panel force S of the second opening degree variable mechanism 20 in this engine speed range. Will remain closed.

As a result, the exhaust gas and the exhaust noise are discharged from the outlet portion 6 b of the inlet pipe 6 to the second chamber 4. The exhaust gas discharged into the second chamber 4 flows to the first chamber 3 through the intermediate pipe 7, and then is discharged to the outside of the muffler shell 2 through the first outlet pipe 8. At this time, the second chamber 4 includes the part of the first control valve 14 and the inlet pipe 6 including the first small hole 11 and the inlet pipe 6 and the resonator pipe portion. Attenuates the slightly higher frequency range (the part of the inlet pipe 6 facing the second chamber 4) and the intermediate pipe 7's conductivity. In other words, the second chamber 4 functions as an intermediate frequency resonator chamber that attenuates the discharge sound of the intermediate frequency.

If the engine speed becomes higher (as a guideline, about 400 to 700 rpm), if the exhaust gas flow into the inlet pipe 6 further increases (if the exhaust pressure further increases) As shown in FIG. 7C, the first control valve 14 and the second control valve 19 are both coil panels that energize the first control valve 14 and the second control valve 19. The opening variable mechanism 15 and the second opening variable mechanism 20 open greatly against the panel force.

As a result, the exhaust gas and the exhaust noise are discharged from the outlet portion 13 b of the second outlet pipe 13 to the outside of the muffler shell 2. At this time, the second chamber 4 changes from the medium frequency i¾ resonator chamber to the expansion chamber, and attenuates a wide frequency range from the medium frequency to the high frequency. In this way, it is possible to mute the low frequency range to the high frequency range in one room according to the change in the exhaust gas flow rate.

According to the silencer 1 configured as described above, the second chamber 4 is changed into a low-frequency type resonator room, a medium-frequency type resonator room, and an expansion room, like the silencer 1 of the first embodiment. By doing so, the discharge sound of a wide frequency can be attenuated without increasing the volume of the muffler.

Further, according to the silencer 1 of the third embodiment, since the two control valves 14 and 19 of the exhaust pressure sensitive type are provided, it is possible to attenuate discharge sound in a wider frequency range.

"Fourth embodiment"

FIG. 8 is a cross-sectional view of the silencer of the fourth embodiment. In the fourth embodiment, the first and first 2 Control valves 1 4 and 1 9 and 1st and 2nd opening variable mechanisms 1 5 and 2 0 The noise low Wm 9 structure is the same as in the third embodiment. 7 and the first outlet pipe 8 are connected by a substantially U-shaped pipe 21.

In this way, when the intermediate pipe 7 and the first outlet pipe 8 are connected by the substantially U-shaped pipe 21, the tail tube with a narrow pipe diameter is a so-called U-turn type, similar to the silencer 1 of the second embodiment. It becomes a tube, and the silencing effect from low frequency to medium frequency can be increased.

When the U-turn tube is lengthened, there is a phenomenon of tail tube resonance that is determined from the tube length. Therefore, a small hole 22 is opened at the site corresponding to the first chamber 3. By forming the small holes 2 2, the tail tube resonance phenomenon can be suppressed. As described above, the silencer 1 of the fourth embodiment has a structure in which the effect of the U-turn long tail is substantially utilized while the influence of the tail tube resonance is divided to suppress the influence.

Further, according to the silencer 1 of the fourth embodiment, when the second chamber 4 is closed, the exhaust gas and the exhaust sound are discharged from the first small hole 11 of the inlet pipe 6 to the first chamber 3. The small hole 22 2 force flows into the first outlet pipe 8, but in this case, since the flow rate is small, the influence on pressure loss and airflow noise is small.

As described above, according to the silencer 1 of the fourth embodiment, the first control valve 14 and the second control valve 19 are stepped (in this example, 2 according to the engine speed (gas flow rate of exhaust gas)). In other words, it is possible to attenuate the discharge sound in a wide frequency band such as a low frequency ¾¾, a medium frequency ¾¾, and a high frequency range.

`` Fifth embodiment ''

FIG. 9 is a cross-sectional view of the silencer of the fifth embodiment, and FIG. 10 (A) is a diagram showing the flow of exhaust gas when the control valve is closed and the second chamber is a low-frequency resonator chamber. (B) is an exhaust when the control valve is slightly opened and the second chamber is a medium frequency resonator chamber. FIG. 10 (C) is a diagram showing the flow of exhaust gas when the control valve is opened and the second chamber is used as the expansion chamber.

The fifth embodiment is not a double tail tube silencer with two outlet pipes as in the first to fourth embodiments, but a so-called single tail tube silencer with a single outlet pipe. In the fifth embodiment, only parts different from the silencer 1 shown in FIG. 1 of the first embodiment will be described, and the same parts will be described. Is omitted.

In the silencer 1 of the fifth embodiment, the noise reduction mechanism 9 is provided in the hollow pipe 23 connected to and connected to the outlet portion 6 b of the inlet pipe 6 in the second chamber 4. A control valve 14 that opens and closes the outlet portion 6 b of the inlet pipe 6 according to the gas flow rate of the flowing exhaust gas, and a variable opening mechanism 15 that changes the opening degree of the control valve 14 stepwise. It consists of a second small hole 16 formed in the hollow pipe 23 that allows exhaust gas to flow into the second chamber 4 according to the opening position of the control valve 14.

The hollow pipe 23 is mounted so as to be connected to the outlet portion 6 b of the inlet pipe 6 and is formed as a cylindrical pipe having a hollow inside. In the hollow pipe 23, a second small hole 16 is formed at a position corresponding to a rotation range of the control valve 14 that allows the outlet portion 6b to be opened and closed. The control valve 14 and the opening variable mechanism 15 have the same configuration as in the first embodiment, and the mounting structure is also the same.

In the silencer 1 of the fifth embodiment, the opening of the inlet portion 8 a of the first outlet pipe 8 is made larger than the other portions. Specifically, the shape of the inlet portion 8a of the first outlet pipe 8 is a funnel shape, and the flare is such that the opening area gradually becomes larger from the inlet toward the back. By making the inlet portion 8a of the first outlet pipe 8 into a flare shape, the exhaust gas flowing into the inlet portion 8a can be separated. It is possible to prevent and allow smooth inflow.

In the silencer 1 of the fifth embodiment, the sound absorbing member 24 is provided so as to surround the outer periphery of the first outlet pipe 8 provided in the first chamber 3. The sound absorbing member 24 is made of glass wool, for example, and is rubbed against the first outlet pipe 8 to enhance the sound absorbing effect.

Further, in the silencer 1 of the fifth embodiment, a plurality of third small holes 25 are formed in a portion corresponding to the second chamber 4 of the first outlet pipe 8. The powerful third small hole 25 is opened so as to be 10% or less with respect to the surface area of the entire outlet pipe. If the third small hole 25 is formed in the first outlet pipe 8 with an aperture ratio of 10% or less, the influence of the third small hole 25 is small in the low frequency range (100 Hz or less), so that it acts as a resonator chamber. The Moreover, at the medium frequency (100 Hz to 150 Hz), the silencing effect of both the resonator room and the expansion chamber can be obtained, and at the high frequency (150 Hz or more), the effect as an expansion chamber can be obtained.

In other words, the third small hole 25 opening to the second chamber 4 has an opening ratio of 10% or less, so that the small hole 25 is not recognized in the low frequency range, and the second chamber 4 functions as a resonator chamber. In the high frequency range, the small hole 25 is recognized, and the second chamber 4 functions as an expansion chamber. When the aperture ratio exceeds 10%, the resonator room does not change to the expansion room, and it becomes an expansion room from the beginning.

If the engine speed is low (approx. 0 to 1000 rpm as a guide), and the exhaust gas flowing into the inlet pipe 6 is small (if the exhaust pressure is low), the control valve 14 is shown in Fig. 10 (A). As shown, the panel force of the opening degree varying mechanism 15 which is a coil panel for energizing the control valve 14 overcomes the exhaust pressure, and the outlet portion 6 b of the inlet pipe 6 Occlude.

If the outlet portion 6 b of the inlet pipe 6 is blocked by the control valve 14, the exhaust gas and the exhaust sound flow out from the first small hole 11 formed in the inlet pipe 6 to the first chamber 3. Discharged through the first outlet pipe 8 from the outlet part 8 b to the outside o

At this time, the first chamber 3 functions as an expansion chamber and the control valve 14 is in a closed state, so that the second chamber 4 functions as a low frequency type resonator chamber that attenuates discharge sound in a low frequency range. In this case, the resonance frequency of the resonator chamber is determined by the diameter and length that determine the conductivity of the intermediate pipe 7 only (the ease of sound entry), so the attenuation frequency depends on the capacity of the second chamber 4. It becomes a low frequency type resonator and starts running. Low frequency and como sound can be greatly attenuated.

If the engine speed increases (as a guideline, about 1 0 0 0 to 4 0 0 0), the exhaust gas flowing into the inlet pipe 6 increases (if the exhaust pressure increases), control is performed. As shown in FIG. 10 (B), the valve 14 is piled on the panel force of the opening degree varying mechanism 15 that is a coil panel that urges the control valve 14, and is formed in the hollow pipe 23. Open 2 small holes 1 6 to release position.

As a result, the exhaust gas and the exhaust noise are discharged from the second small hole 16 formed in the hollow pipe 23 into the second chamber 4. At this time, the second chamber 4 includes the conductivity of the second small hole 16 and the resonator pipe (the portion of the inlet pipe 6 facing the second chamber 4 from the rear of the small hole 11) and the intermediate pipe 7 Attenuates the slightly higher frequency range, which is the frequency range where the conductivity is combined. That is, the second chamber 4 functions as a medium frequency type resonator chamber that attenuates the discharge sound of anyone at medium frequency.

The exhaust gas discharged to the second chamber 4 is discharged to the first chamber 3 through the intermediate pipe 7, and then discharged to the outside of the muffler shell 2 through the first outlet pipe 8. The

If the engine speed increases further (as a guideline, about 400 to 700 rpm), if the exhaust gas flow into the inlet pipe 6 further increases (if the exhaust pressure further increases) As shown in FIG. 10 (C), the control valve 14 opens largely against the panel force of the opening variable mechanism 15 that is a coil panel that urges the control valve 14. As a result, a large amount of exhaust gas and exhaust noise is exhausted from the second small hole 16 formed in the hollow pipe 23 and the rear opening to the second chamber 4. Therefore, the second chamber 4 changes from the middle frequency resonator chamber to the expansion chamber, and attenuates a wide frequency range from the middle frequency to the high frequency range. Thus, in the silencer 1 of the fifth embodiment, it is possible to mute the low frequency range to the high frequency range in one room according to the change in the exhaust gas flow rate.

According to the silencer 1 configured as described above, as in the silencer 1 of the first embodiment of the double tail tube type, the second chamber 4 is divided into a low frequency type resonator room, a medium frequency type resonator room, By changing to the expansion chamber, this single tail tube type can attenuate the discharge sound of a wide frequency without increasing the volume of the muffler.

Further, according to the silencer 1 of this embodiment, the first outlet pipe 8 is formed with the third small hole 25 that opens to the second chamber 4, so that the third outlet hole 8 is formed in the high frequency range. By recognizing the small hole 25, the second chamber 4 can be changed to an expansion chamber.

Further, according to the silencer 1 of this embodiment, the noise of the exhaust gas flowing into the muffler can be increased by making the opening of the inlet portion 8 a of the first outlet pipe 8 larger than the opening of other portions. And pressure loss can be reduced.

Further, according to the silencer 1 of this embodiment, since the sound absorbing member 24 is provided so as to surround the outer periphery of the first outlet pipe 8 provided in the first chamber 3, at the upstream portion of the muffler. High-frequency sounds such as generated airflow sounds and high-frequency sounds such as expansion, contraction, and turbulent sound generated when passing through valves can be absorbed before discharge.

"Sixth embodiment"

FIG. 11 is a cross-sectional view of the silencer of the sixth embodiment. In the sixth embodiment, the structure of the noise structure 9 comprising the control valve 14, the opening variable mechanism 15 and the second small hole 16 is the same as that of the fifth embodiment, but the first chamber 3 has In this structure, the intermediate pipe 7 and the first outlet pipe 8 are connected by a substantially U-shaped pipe 26. The other end portion 7b of the intermediate pipe 7 that opens to the second chamber 4 has a flare shape.

In this way, when the intermediate pipe 7 and the first outlet pipe 8 are connected by the substantially U-shaped pipe 26, the tail tube with a narrow pipe diameter becomes a so-called U-turn tube, and a silencing effect from low to medium frequencies is achieved. Can be increased.

When this u-turn tube is lengthened, there is a phenomenon of tail tube resonance determined from the tube length, so a small hole 18 is opened at a site corresponding to the first chamber 3. By forming the small holes 18, the tail tube resonance phenomenon can be suppressed. Thus, the silencer 1 of the sixth embodiment has a structure in which the effect of the U-turn mouthtail is substantially utilized, but the influence is suppressed by dividing the tail tube resonance. If the aperture ratio of the small hole 18 opened in the first chamber 3 is set to 10% or less, the tail tube resonance frequency is divided with respect to the sound of 20 Hz or higher which is the tail tube resonance low frequency range. I can refuse.

Further, the structure of the silencer 1 is such that when the second chamber 4 is closed, the exhaust gas is exhausted from the first small hole 11 formed in the inlet pipe 6 to the first chamber 3, and then the middle It flows into the U-shaped pipe 26 through the small hole 18 formed in the pipe 7, but since the amount of the inflow is small, the effect on pressure loss and airflow noise is small.

As described above, the conventional resonator structure reduces the fixed frequency in the specific rotation speed range. Although it is an unnecessary room in the other rotational speed range, in the silencer 1 of the fifth embodiment and the sixth embodiment, in stages (in this example, depending on the engine rotational speed (gas flow rate of exhaust gas)) (3 steps), it is possible to attenuate the discharge sound in a wide frequency band such as low frequency, medium frequency and high frequency.

"Seventh embodiment"

Fig. 12 is a cross-sectional view of the silencer of the seventh embodiment, Fig. 13 (A) is an enlarged vertical cross-sectional view of the main part where the control valve is provided, and Fig. 13 (B) is provided with the control valve. FIG.

In the control of the seventh embodiment, the noise reduction mechanism 9 is configured to close the second small hole 16 when the control valve 14 is closed. In the seventh embodiment, only parts different from the silencer 1 shown in FIG. 1 of the first embodiment will be described, and description of the same parts will be omitted.

The surface of the control valve 14 is curved with respect to the gas flow direction. More specifically, when the control valve 14 is in the closed state, it has a curved shape that slightly protrudes from the upper end portion toward the lower end portion on the side opposite to the exhaust gas flow direction. Further, as will be described later, when the control valve 14 is in the position C where it is wide open (see FIG. 13 (A)), the control valve 14 is configured so that the surface facing the exhaust gas flow is convex. The That is, at this time, the control valve 14 has its convex surface facing in a direction perpendicular to the flow of exhaust gas.

The outlet portion 6 b of the inlet pipe 6 is adapted to match the curvature of this control valve 14 It is configured in shape. As a result, when the control valve 14 is in the closed position A (see FIG. 13 (A)), the outlet portion 6 b of the inlet pipe 6 is blocked, and the exhaust gas flows from the inlet pipe 6 to the outlet pipe 1 3. To be discharged.

Further, the control valve 14 is configured to close the second small hole 16 provided in the outlet pipe 13 when the control valve 14 is closed. As a result, when the control valve 14 is in the closed position A (see FIG. 13 (A)), the control valve 14 closes the second small hole 16 and the exhaust gas flows into the second chamber. Limit the discharge from 4 to the exit pipe 1 3.

If the engine speed is low (approx. 0 to 1 0 0 0 as a guideline), the exhaust valve flowing into the inlet pipe 6 has a small flow rate (when the exhaust pressure is low). As shown in (A), the outlet force force S of the variable opening mechanism 15 which is a coil panel for energizing the control valve 14 is superior to the exhaust pressure S, and the outlet portion 6 b of the inlet pipe 6 is closed.

If the outlet portion 6 b of the inlet pipe 6 is blocked by the control valve 14, the exhaust gas and the exhaust sound flow out from the first small hole 11 formed in the inlet pipe 6 to the first chamber 3. At this time, the first chamber 3 acts as an expansion chamber and the control valve 14 is in a closed state, so that the second chamber 4 is discharged from the outlet portion 8b through the first outlet pipe 8. Is connected to the first chamber 3 only by the intermediate pipe 7 and functions as a low-frequency resonator chamber that attenuates the discharge sound in the low-frequency range. In this case, the resonance frequency of the resonator chamber is determined by the diameter and length that determine the conductivity of the intermediate pipe 7 only (the ease of sound entry). However, it becomes a low-frequency type resonator and starts running, so that the low-frequency como sound can be significantly attenuated.

The exhaust gas and the exhaust sound flow out from the first small hole 11 formed in the inlet pipe 6 to the first chamber 3, and pass through the first outlet pipe 8 to the outside from the outlet portion 8b. Is issued. Here, as in the first embodiment (FIG. 1) described above, when the control valve 14 is in front of the second small hole 16, a part of the exhaust gas flowing out into the first chamber 3 is Then, it passes through the intermediate pipe 7 and is discharged from the second small hole 16 to the second outlet pipe 13. This may reduce the silencing effect of the resonator room.

In contrast, in the seventh embodiment, as shown in FIG. 14 (A), the second small hole 16 is closed when the control valve 14 is in the closed state. The sound is discharged only from the outlet pipe 8 without flowing out from the second chamber 4 to the outlet pipe 13. As a result, the second chamber 4 will surely function as a low-frequency resonator chamber, and the engine speed will be high (as a guideline, about 100 to 400 rpm), the exhaust gas flowing into the inlet pipe 6 When the flow rate increases (when the exhaust pressure increases), as shown in Fig. 14 (B), the control valve 14 is a variable opening mechanism that is a coil panel that urges the control valve 14. 1 Open the second small hole 16 formed in the second outlet pipe 1 3 against the panel force of 5 to the position to release it.

As a result, the exhaust gas and the exhaust noise are discharged from the second small hole 16 formed in the second outlet pipe 13 into the second chamber 4. At this time, the second chamber 4 is connected to the conductivity of the second small hole 16 and the resonator pipe (the portion of the inlet pipe 6 facing the second chamber 4 from the rear of the first small hole 11) and the middle. Attenuates the slightly higher frequency range, which is the combined frequency range of pipe 7. That is, the second chamber 4 functions as a medium frequency type resonator chamber that attenuates the discharge sound in the medium frequency range. The

The exhaust gas discharged to the second chamber 4 is discharged to the first chamber 3 through the intermediate pipe 7 and then discharged to the outside of the muffler shell 2 through the first outlet pipe 8.

When the engine speed becomes higher (as a guideline, about 400 to 700 rpm) When the flow rate of the exhaust gas flowing into the inlet pipe 6 further increases (when the exhaust pressure further increases) As shown in FIG. 14 (C), the control valve 14 opens greatly against the panel force of the opening degree varying mechanism 15 which is a coil panel that urges the control valve 14. As a result, the exhaust gas and the exhaust noise are discharged from the outlet portion 13 b of the second outlet pipe 13 to the outside of the muffler shell 2. At this time, the second chamber 4 changes from the medium frequency type resonator chamber to the expansion chamber, and attenuates a wide frequency range from the medium frequency ^^ to the high frequency range. The expansion chamber plays a role of silencing through the first small hole 11 of the inlet pipe 6 and the expansion from the intermediate pipe 7 to the second chamber and the contraction of the outlet pipe 13. In this way, it is possible to mute the low frequency to high frequency range in one room according to changes in the exhaust gas flow rate.

In particular, in the seventh embodiment, the control valve 14 is provided with a curved shape that is slightly convex with respect to the exhaust gas flow. With this shape, when the control valve 14 is in the open state, the flow of exhaust gas near the surface of the control valve 14 becomes difficult to separate, and airflow noise can be reduced. In addition, this shape generates lift due to the blade effect when the exhaust pressure increases, so that the control valve 14 can be opened larger by piled on the panel force, and the pressure loss of the exhaust gas can be reduced.

According to the silencer 1 configured as described above, as in the first embodiment, the second chamber 4 is changed into a low-frequency type resonator chamber, a medium-frequency type resonator chamber, and an expansion chamber. Reduces discharge noise over a wide range of frequencies without increasing Can be attenuated.

Further, according to the silencer 1 of the seventh embodiment, when the control valve 14 is in the closed state, the second small hole 16 is closed, so that the silencing effect of the low frequency type resonator chamber can be further enhanced. Can do.

Further, according to the silencer 1 of the seventh embodiment, since the control valve 14 is slightly curved with respect to the exhaust gas flow direction, the flow noise of the exhaust gas can be reduced. Furthermore, when the exhaust gas has a high flow rate, lift due to the blade effect is generated and the opening can be made large, so that the pressure loss of the exhaust gas can be reduced.

`` Eighth embodiment ''

FIG. 15 is a cross-sectional view of the silencer of the eighth embodiment. As in the fourth embodiment shown in FIG. 8, the eighth embodiment has a structure in which the intermediate pipe 7 and the first outlet pipe 8 are connected by a substantially U-shaped pipe 21 in the first chamber 3.

Furthermore, as in the seventh embodiment shown in FIG. 12, the control valve 14 is curved, and the second small hole 16 is closed when the control valve 14 is in the closed state. Configured.

In this way, when the intermediate pipe 7 and the first outlet pipe 8 are connected by the substantially U-shaped pipe 21, the tail tube with a narrow pipe diameter is a so-called U-turn type, similar to the silencer 1 of the fourth embodiment. It becomes a tube, and the silencing effect in the low to medium frequency range can be increased.

In the silencer 1 of the eighth embodiment, the sound absorbing member 28 is provided so as to surround the outer periphery of the first outlet pipe 8 provided in the second chamber 4. The sound absorbing member 28 is made of glass wool, for example, and is wound around the first outlet pipe 8 to enhance the sound absorbing effect.

As described above, according to the silencer 1 of the eighth embodiment, as in the fourth embodiment, By changing the first control valve 14 and the second control valve 19 stepwise (in this example, two steps) according to the engine speed (exhaust gas flow rate), low frequency, medium frequency «, high frequency And the discharge sound in a wide frequency band can be attenuated.

Further, according to the silencer 1 of the eighth embodiment, when the control valve 14 is closed, the second small hole 16 is closed, so that the silencing effect of the low frequency type resonator chamber can be further enhanced. Can do.

Further, according to the silencer 1 of the eighth embodiment, since the control valve 14 is slightly curved with respect to the flow direction of the exhaust gas, the flow noise of the exhaust gas can be reduced. Furthermore, when the exhaust gas flow rate is high, lift due to the blade effect is generated and can be opened largely, so that the pressure loss of the gas gas can be reduced.

"Ninth embodiment"

FIG. 16 is a cross-sectional view of the silencer of the ninth embodiment. As in the fifth embodiment shown in FIG. 9, the ninth embodiment is an example in which the noise reduction mechanism of the present invention is provided in a so-called single tail tube silencer having a single outlet pipe.

Thus, in the silencer 1 of the ninth embodiment, the single tail tube type silencer 1 is the same as the double tail tube silencer 1 of the first embodiment, as in the fifth embodiment. By changing the two chambers 4 into a low-frequency resonator chamber, a medium-frequency resonator chamber, and an expansion chamber, it is possible to attenuate the discharge sound of a wide frequency without increasing the volume of the muffler.

Further, according to the silencer 1 of the ninth embodiment, when the control valve 14 is closed In addition, since the second small hole 16 is closed, the silencing effect of the low-frequency resonator chamber can be further enhanced.

Further, according to the silencer 1 of the ninth embodiment, since the control valve 14 is slightly curved with respect to the flow direction of the exhaust gas, the flow noise of the exhaust gas can be reduced. Furthermore, when the exhaust gas flow rate is high, lift due to the blade effect is generated and can be opened greatly, so that the pressure loss of the exhaust gas can be reduced.

"First Embodiment"

FIG. 17 is a cross-sectional view of the silencer of the 10th embodiment. In the 10th embodiment, as in the sixth embodiment shown in FIG. 11, the intermediate pipe 7 and the first outlet pipe 8 are connected to the first chamber 3 by a substantially U-shaped pipe 26. The structure is made to be. The other end portion 7 b of the intermediate pipe 7 that opens to the second chamber 4 has a flare shape.

Further, similarly to the seventh embodiment shown in FIG. 12, the control valve 14 is curved, and the second small hole 16 is closed when the control valve 14 is closed. .

Thus, in the 10th embodiment, as in the 6th embodiment, the single tail tube silencer 1 is also stepwise (in this example, 3) according to the engine speed (gas flow rate of exhaust gas). Therefore, it is possible to attenuate the discharge sound in a wide frequency range such as low frequency range, medium frequency range, and high frequency range.

Further, according to the silencer 1 of the 10th embodiment, the second small hole 16 is closed when the control valve 14 is in the closed state, so that the silencing effect of the low frequency type resonator chamber is obtained. Can be increased.

Further, according to the silencer 1 of the tenth embodiment, since the control valve 14 is slightly curved with respect to the exhaust gas flow direction, the flow noise of the exhaust gas can be reduced. Furthermore, when the exhaust gas flow rate is high, lift due to the blade effect is generated and greatly increased. Since it can be opened, the pressure loss of the exhaust gas can be reduced. "First Embodiment 1"

Fig. 18 (A) is an enlarged vertical sectional view of the main part where the control valve of the first embodiment is provided, and Fig. 18 (B) is the main part of the part where the control valve of the first embodiment is provided. FIG.

In the first embodiment, as in the seventh to tenth embodiments described above, the control valve 14 has a curved shape, and the second small hole 16 is closed when the control valve 14 is closed. It was configured to do so.

Furthermore, the angle of the tip portion (edge) of the control valve 14 is configured to be small. More specifically, as shown in FIG. 18 (B), when the control valve 14 is in the wide open position C, the edge 14 4 a force that becomes the tip of the exhaust gas flow direction Exhaust gas flow The shape gradually becomes acute as it goes in the direction. As described above, in the first embodiment, the effect of the seventh to 11th embodiments is remarked, and the angle of the edge 14 a which is the tip portion of the control valve 14 is directed in the exhaust gas flow direction. Therefore, the occurrence of air flow separation near the surface of the control valve 14 is suppressed. As a result, even when the exhaust gas flow rate is large and the control valve 14 is in the position C where it is greatly opened with respect to the outlet pipe 13, airflow noise generated by the control valve 14 is reduced.

While specific embodiments to which the present invention is applied have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

For example, the silencer of this embodiment can be used as a silencer for an automobile equipped with a normal internal combustion engine, a silencer for a hybrid car that combines an engine and an electric motor, or hydrogen and oxygen. It can also be used as a silencer for fuel cell vehicles powered by the power generated by the reaction. Further, the silencer 1 of the fifth embodiment has a flare structure in which the opening of the inlet part 8a of the first outlet pipe 8 is larger than the opening of other parts, but the noise during the inflow of exhaust gas If the pressure loss does not contribute significantly, it is not necessary to adopt the flare structure.

Further, in the silencer 1 of the fifth embodiment, the sound absorbing member 24 is provided so as to surround the outer periphery of the first outlet pipe 8 provided in the first chamber 3, but the contribution rate of the airflow generated sound is small. ^ Does not require the sound absorbing member 24.

In the seventh to tenth embodiments, the control valve 14 is curved, but any shape can be used as long as the second small hole 16 can be closed when the control valve 14 is closed. . For example, as long as the airflow noise generated in the control valve 14 is negligible, it may be flat as in the first embodiment (FIGS. 1 and 2).

In addition, the control valve 14 does not have a uniform thickness, and the second small hole 16 around the thin plate-shaped control valve 14 is closed so that the second small hole 16 is closed when the control valve 14 is closed. A flange may be provided at the corresponding position.

Further, the surface of the control valve 14 may be provided with a groove-shaped unevenness process (so-called vortex generator) so as to reduce airflow noise.

This application is a patent application filed with the Japan Patent Office on June 6, 2007. 0 0 7-1 5 0 4 8 1, 2 0 0 August 10, 2010 The Japan Patent Office 2 0 0 7-2 0 9 8 6 0 and 2 0 0 Patent application filed with the Japan Patent Office on May 8, 2008 2 0 0 8-1 2 2 2 2 2 Claims priority based on. The entire contents of these applications are incorporated herein by reference.

Claims

The scope of the claims

1. A cylindrical muffler shell (2),

A partition structure (5) that divides the internal space of the self-muffler shell (2) into the first chamber (3) and the second chamber (4);

The first chamber (3) has a first hole (11) at a position corresponding to the first chamber (3), an outlet portion (6b) is provided in the second chamber (4), and exhaust gas is introduced into the muffler shell (2). The entrance passage (6)

An intermediate passage (7) fixed to the partition structure (5) and connecting the first chamber (3) and the second chamber (4);

A first outlet passage (8) for discharging the exhaust gas silenced in the muffler shell (2) to the outside;

The second chamber (4) includes a low frequency resonator chamber for attenuating low frequency discharge sound, a medium frequency type resonator chamber for attenuating medium frequency discharge sound, and an expansion chamber for attenuating high frequency discharge sound. A silencer equipped with a low noise level, structure (9).

2. A silencer according to claim 1,

The low noise structure (9)

In the second chamber (4), a connection portion between the inlet passage (6) and the second outlet passage (13) connected to and connected to the outlet portion (6b) of the inlet passage (6) A control valve (14) provided to open and close the outlet portion (6 b) of the inlet passage (6) according to the flow rate of the exhaust gas flowing through the inlet passage (6);

An opening variable mechanism (15) for changing the opening of the control valve (14) stepwise; A second hole (13) formed in the second outlet passage (13) for allowing exhaust sound and exhaust gas to flow into the second chamber (4) according to the opening position of the control vanolev (14). 1 6) and power

Silencer.

3. The silencer according to claim 1,

The low noise structure (9)

The outlet portion (6b) of the inlet passage (6) is opened and closed according to the gas flow rate of the exhaust gas flowing in the inlet passage (6). The first control valve (14)

A first opening variable mechanism (15) for changing the opening of the first control valve (14) stepwise;

On the extension line of the inlet passage (6), the inlet portion (13) of the second outlet passage (13) provided through the end plate (12) on the rear end side of the muffler shell (2). The first control valve (14) is opened to open a second $ lJ control that opens and closes the inlet portion (13a) according to the gas flow rate of the exhaust gas flowing into the second chamber (4) when the first control valve (14) is opened. No Nolev (1 9),

And a second opening variable mechanism (2 0) for changing the opening of the second control valve (1 9) stepwise.

Silencer.

4. A silencer according to claim 1,

The low noise structure (9)

The second chamber (4) is connected to the outlet portion (6b) of the inlet passage (6). A control valve (14) provided in the hollow passage (23) for opening and closing the outlet portion (6b) of the inlet passage (6) according to the gas flow rate of the exhaust gas flowing through the inlet passage (6),

A variable opening mechanism (15) for changing the opening degree of the control valve (14) stepwise, and exhaust sound and exhaust gas to the second chamber (4) according to the opening position of the control valve (14). A second hole (16) formed in the hollow passage (23) through which water flows.

Silencer.

5. The silencer according to any one of claims 2 to 4,

In the first chamber (3), the intermediate passage (7) and the first outlet passage (8) are connected by a substantially U-shaped passage (17, 21, 26).

Silencer.

6. A silencer according to claim 4,

The first outlet passage (8) is formed with a third hole (25) that opens into the second chamber (4).

Silencer.

7. A muffler according to claim 2,

The second hole (16) is provided in the outlet passage (13) at a position closed by the control valve (14) when the control valve (14) is in a closed state.

Silencer.

8. A silencer according to claim 2,

The control valve (14) has a curved shape with a convex surface facing the flow of exhaust gas when opened.

Silencer.

9. A silencer according to claim 8,

The control valve (14) is formed to have an acute angle when the control valve (14) is in the open state as it moves toward the downstream side of the exhaust gas flow.

Silencer.