JPH0687616U - Silencer - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a silencer having a simple structure and capable of reducing exhaust noise in the entire engine speed range. [Structure] An outer cylinder 1 having both end openings closed by end plates 3 and 5 is partitioned by partition plates 7 and 9, and an exhaust lead-out pipe is provided in a chamber 15 partitioned by the end plate 5 and a partition plate 9 adjacent thereto. 21 through the partition plate 9, two pipes 25 are respectively inserted into the partition plate 9, and the inside / outside of the one pipe 25 flows from the exhaust introduction pipe 17 attached to the end plate 3 to the middle and high rotation speeds of the engine. A first valve 33 that opens the flow path by the exhaust gas pressure in the area is provided, and a second valve 37 with a small hole 35 that is connected to the first valve 33 via the connecting member 41 is installed in the exhaust outlet pipe 21. Then, the second valve 37 is opened and closed in association with the opening and closing of the first valve 33 to open and close the exhaust gas outlet passage.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a silencer mounted on a vehicle exhaust system.

[0002]

[Prior art]

 In order to reduce the exhaust noise when the vehicle is running, a muffler has been conventionally installed in the vehicle exhaust system. Is muted.

By the way, recently, as disclosed in Japanese Utility Model Application Laid-Open No. 1-115816, a muffler of this type has been improved so that a small hole is formed in a resonance tube in a resonance chamber and the control can be freely moved to this portion. By providing a valve and moving the control valve in the area where small holes are provided according to the operating condition of the engine, it is possible to reduce the exhaust noise in a wide frequency range by adjusting the aperture ratio of the resonance tube. The muffler and the exhaust pipe of the vehicle exhaust system are dual type, one exhaust pipe is equipped with a control valve, and the exhaust gas flow is controlled by opening and closing the control valve according to the engine speed. One that aims to reduce exhaust noise from a low rotation range to a high rotation range of an engine, and further, a first exhaust pipe and a second exhaust pipe that are arranged in parallel as disclosed in Japanese Utility Model Laid-Open No. 3-6011. To each In the exhaust silencer with the silencer attached and the first exhaust pipe and the second exhaust pipe communicating with the upstream side of both silencers, at the low engine speed at the downstream side of the silencer of the first exhaust pipe. An exhaust muffler is known that is equipped with a control valve that is closed to reduce exhaust noise in the low engine speed range.

[0004]

[Problems to be solved by the device]

 Therefore, the above-described conventional silencer and exhaust silencer each have an extremely complicated structure because the engine information is input to the control means and the operation of the control valve is controlled by electronic control. Further, there is a drawback that the cost becomes high.

Of course, in the exhaust silencer disclosed in Japanese Utility Model Laid-Open No. 3-6011, only the damping effect of a specific frequency can be obtained, and it is disclosed in Japanese Utility Model Laid-Open No. 1-115816. Even in the muffler, since the muffling element is a resonator, the frequency range that can reduce exhaust noise was naturally limited.

The present invention was devised in view of such circumstances, and it is possible to reduce exhaust noise from a low rotation speed region of the engine to a medium / high rotation speed region. It is an object of the present invention to provide a silencer having a simple structure that does not require electronic control.

[0007]

[Means for Solving the Problems]

 In order to achieve such an object, the silencer according to the present invention divides an outer cylinder whose both ends are closed by end plates into a plurality of partition plates, and divides the downstream end plate and a partition plate adjacent to it. Exhaust gas exhaust pipe is penetrated into the partitioned chamber, two pipes are inserted into the partition plate, respectively, and flow into the inside of one pipe from the exhaust gas intake pipe attached to the upstream end plate. A first valve that opens the exhaust gas flow path by the exhaust gas pressure in the middle / high rotation range of the engine is provided, and a small hole that is connected to the first valve through a connecting member is provided in the exhaust outlet pipe. A second valve is attached, and the second valve opens and closes the exhaust gas outlet pipe flow path in conjunction with opening and closing of the first valve in the pipe.

[0008]

[Action]

 According to the present invention, since the flow rate of exhaust gas flowing into the silencer is small when the engine is running at low speed, the first valve in the pipe closes the flow path of the pipe, and similarly, in the exhaust outlet pipe. The second valve of is also closed and the exhaust gas passes through the small hole.

Therefore, since the chamber partitioned by the downstream end plate and the partition plate adjacent thereto functions as a common noise chamber, the exhaust noise is silenced by the resonance damping action of the chamber, and in addition, the exhaust gas is exhausted. Since the exhaust gas passes through the small hole of the second valve in the exhaust outlet pipe, the shape of the tube is narrowed, which helps reduce noise in the low frequency region when the engine is running at low speed. , It effectively functions as a measure against muffled noise to ensure quietness in the passenger compartment.

On the other hand, when the engine shifts to the middle / high speed region and the flow rate of exhaust gas into the silencer increases, the first valve in the pipe opens at the pressure of the exhaust gas to open the flow path of the pipe, Then, in conjunction with this, the second valve completely opens the flow path of the exhaust gas outlet pipe, so the above-mentioned chamber functioning as a resonance chamber becomes an expansion chamber, and as a result, exhaust energy is expanded and attenuated in that chamber. The sound is silenced by the action, and the noise reduction measures in the middle and high engine speed range of the engine are taken.

[0011]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a silencer according to an embodiment of the present invention. In the figure, reference numeral 1 denotes an outer cylinder whose both ends are closed by end plates 3 and 5, and the inside of the outer cylinder 1 has two partition plates 7, Three chambers, that is, a first chamber 11, a second chamber 13, and a third chamber 15 are defined from the upstream end plate 3 side by 9.

An exhaust gas introduction pipe 17 is inserted into the upstream end plate 3 so as to penetrate both partition plates 7 and 9, and the exhaust gas introduction pipe 17 has an end portion on the insertion side that is located in the third chamber 15. In addition, a plurality of small holes 19 are formed in the peripheral wall located in the second chamber.

Similarly, an exhaust lead-out pipe 21 is inserted into the downstream end plate 5 so as to pass through both partition plates 7 and 9, and the exhaust lead-out pipe 21 has a first end on the insertion side. It opens into chamber 11. The partition plate 7 is provided with a pipe 23 that communicates the first chamber 11 and the second chamber 13, and the partition plate 9 is provided with a pipe 25 that communicates the second chamber 13 and the third chamber 15. Each is inserted coaxially.

Further, in the drawing, 27 is a flow path forming member that constitutes a part of the pipe 25 and the exhaust gas outlet pipe 21, and the flow path forming member 27 is a pair of half-split members 27 a as shown in FIG. , 27b in the middle to form two flow channels 29, 31 and have a cross-sectional spectacle shape. Then, as shown in FIG. 1, by connecting these in the middle of the pipe 23 of the pipe 23 of the third chamber 15 and the exhaust lead-out pipe 21, as shown in FIG. However, each of them is a part of the exhaust gas flow path of the pipe 25 and the exhaust outlet pipe 21.

As shown in FIG. 3, a first valve 33 that opens and closes the flow path of the pipe 25 is attached in the flow path 29 via a hinge 34, and is used in an engine with a large exhaust gas flow rate. At high rotation speed, the first valve 33 is opened by the pressure of the exhaust gas G introduced from the third chamber 15 through the exhaust introduction pipe 17 as shown in FIG. 4, and the flow path of the pipe 25 is opened. There is. On the other hand, a second valve 37 having a small hole 35 is also mounted in the flow path 31 forming a part of the exhaust gas outlet pipe 21 via a hinge 34.

As shown in FIG. 3, a connecting member insertion passage 39 is formed between the flow paths 29 and 31 by aligning the half-split members 27a and 27b in the middle. A connecting member 41 made of a wire is connected between the first and second valves 33 and 37 via the passage 39. Then, as described above, when the first valve 33 is opened by the exhaust gas pressure in the medium / high rotation region of the engine to open the flow path of the pipe 25, the second valve 37 connected by the connecting member 41 is interlocked with this. Then, the flow passage of the exhaust gas discharge pipe 21 is completely opened, and when the engine rotation shifts to the low rotation speed region and the exhaust gas flow rate decreases and the first valve 33 closes the flow passage of the pipe 25, it interlocks with this. Thus, the second valve 37 is closed so that the exhaust gas G passes through the small hole 35 as shown in FIG.

Therefore, when the first valve 33 opens the flow path of the pipe 25 as described above, the third chamber 15 functions as an expansion chamber together with the first chamber 11 and the second chamber 13, and the first valve 33 When the valve closes the flow path of the pipe 25, the third chamber 15 functions as a resonance chamber.

As described above, the second valve 37 is interlocked with the opening and closing of the first valve 33 via the connecting member 41, but when the first valve 33 is opened by the pressure of the exhaust gas G, the second valve 37 is opened. In 37, not only the pulling force of the connecting member 41 but also the pressure of the exhaust gas G flowing from the first chamber 11 into the exhaust outlet pipe 21 acts synergistically to open the flow path.

Since the silencer according to the present embodiment is configured in this way, the engine is driven, the exhaust gas G flows into the silencer through the exhaust introduction pipe 17, and the exhaust energy is silenced. Although it is propagated inside the reactor, the exhaust gas flow rate is low at low engine speed, so the first valve 33 closes the flow path of the pipe 25 as shown in FIG. Also, the exhaust gas G passes through the small hole 35.

Therefore, the exhaust energy propagated in the silencer is expanded by the expansion damping action in the second chamber 13 and the first chamber 11 functioning as the expansion chamber and the resonance damping action in the third chamber 15 functioning as the resonance chamber. In addition, the exhaust gas G is silenced and passes through the small hole 35 of the second valve 37 in the exhaust lead-out pipe 21, so that the tube diameter is narrowed, which also contributes to low engine speed. In the low frequency region, noise countermeasures will be taken, and it will effectively function as a muffled noise countermeasure to ensure quietness in the passenger compartment.

When the engine shifts to the medium / high speed region and the flow rate of exhaust gas into the silencer increases, the first valve 33 opens at the pressure of the exhaust gas G to open the pipe 25 as shown in FIG. Is opened, and in conjunction with this, the second valve 37 completely opens the flow passage of the exhaust outlet pipe 21, so that all of the first chamber 11, the second chamber 13, and the third chamber 15 are opened. It functions as an expansion chamber, and the exhaust energy is silenced by the expansion damping action, which makes it possible to mitigate noise in the middle and high engine speed regions of the engine.

FIG. 6 shows the discharge sound calculation result when the valve is closed and the discharge sound calculation result when the valve is open. The horizontal axis represents the engine speed, and the vertical axis represents the discharge sound level. ing.

Thus, according to this embodiment, by opening and closing the first valve 33 according to the engine rotation state, the third chamber 15 as a muffling element is switched between the expansion chamber and the resonance chamber, and Also, since the opening and closing of the first and second valves 33 and 37 is performed by using the pressure of the exhaust gas G instead of the conventional electronic control, a simple structure as shown in FIG. It has become possible to take measures to muffle the target frequency according to the rotation speed.

The present invention is not limited to the structure of the above-described embodiment, and for example, as shown in FIG. 7, the first valve 33 is moved into the pipe 25 through the hinge 34 at the pipe end of the pipe 25. The small chamber 43 is provided outside the end plate 5, and the second valve 37 is also attached inside the exhaust lead-out pipe 21 via the hinge 34.

In the small chamber 43, the guide roller 45 of the connecting member 41 that connects the valves 33 and 37 is slidably arranged in the groove 47. As shown in FIG. When the 1-valve 33 closes the exhaust gas flow path of the pipe 25, the second valve 37 also closes so that the exhaust gas G passes through the small hole 35. Then, when the engine shifts to the middle / high speed region and the exhaust gas flow rate increases and the first valve 33 opens at that pressure to open the flow path, the guide roller 45 causes the groove 47 to move as shown by the chain double-dashed line. The inside is slid, and in conjunction with this, the second valve 37 completely opens the exhaust gas discharge pipe 21.

Therefore, according to the present embodiment as well, similar to the above-described embodiments, the third chamber 15 as a muffling element can be switched between the expansion chamber and the resonance chamber according to the rotation state of the engine. At the same time, since both valves 33 and 37 are opened and closed by using the pressure of the exhaust gas G, the intended purpose can be achieved.

Although a wire is used as the connecting member 43 for connecting the first and second valves 33, 37 in each of the above-described embodiments, the connecting member 43 is not limited to a wire, and a link mechanism or the like may be used. You may use the connection member of.

Further, in each of the above embodiments, the exhaust introduction pipe 17 is penetrated through the partition plates 7 and 9, and one of the two pipes 25 inserted into the partition plate 9 is also used as the exhaust introduction pipe 17. However, it is also possible to open the insertion side end of the exhaust gas introduction pipe to the second chamber 13 and then insert another pipe 25 coaxially with the partition plate 9 in this case. The first valve 33 may be provided on the pipe 25 side.

[0029]

[Effect of device]

 As described above, according to the muffler of the present invention, the chamber as a muffling element is switched between the expansion chamber and the resonance chamber by opening and closing the first valve according to the engine rotation condition. Since the first and second valves are opened and closed by using the pressure of the exhaust gas instead of the conventional electronic control, a simple structure is used to reduce the noise at the target frequency according to the engine speed. Became possible.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a silencer according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an enlarged sectional view of a mounting portion of a valve.

FIG. 4 is a sectional view of a mounting portion of the valve showing an open state of the valve.

FIG. 5 is a cross-sectional view of a mounting portion of the valve showing an open state of the valve.

FIG. 6 is a graph showing a discharge sound calculation result according to the present embodiment.

FIG. 7 is a cross-sectional view of essential parts in another embodiment of the present invention.

[Explanation of symbols]

 1 Outer Cylinder 3,5 End Plate 7,9 Partition Plate 11 First Chamber 13 Second Chamber 15 Third Chamber 17 Exhaust Inlet Pipe 19,35 Small Hole 21 Exhaust Outlet Pipe 23,25 Pipe 27 Channel Forming Member 29,31 Flow path 33 First valve 37 Second valve 41 Connecting member 43 Small chamber

Claims (1)

[Scope of utility model registration request] 1. An outer cylinder (1) having both end openings closed by end plates (3, 5) is partitioned by a plurality of partition plates (7, 9) and is adjacent to a downstream end plate (5). An exhaust gas outlet pipe (2) is provided in a chamber (15) partitioned by the partition plate (9).
1) is penetrated and two pipes (2
5) each of which is inserted into the pipe (25) of the engine, and exhaust gas in the middle and high rotation regions of the engine which flows from the exhaust introduction pipe (17) which is inserted into the upstream end plate (3). A first valve (33) for opening the exhaust gas flow path by pressure is provided, and the first valve (33) is provided in the exhaust outlet pipe (21).
A second valve (37) having a small hole (35) connected to the valve (33) via a connecting member (41) is mounted, and the second valve (37) is connected to the first valve in the pipe (25). A silencer characterized in that an exhaust gas outlet pipe flow path is opened and closed in conjunction with opening and closing of a valve (33).