JP4073859B2 - Silencer - Google Patents

Description

  The present invention relates to a silencer that is connected to an exhaust system of an engine for vehicles or the like to reduce exhaust noise.

Conventionally, an exhaust pipe is provided in the silencer, and in the exhaust pipe, the exhaust gas flowing into the silencer is guided and muffled and discharged to the atmosphere. It is composed of a larger diameter exhaust pipe, and a small diameter exhaust pipe is housed inside a large diameter exhaust pipe, so that two exhaust pipes of small diameter and large diameter are combined into one silencer in the silencer. What gathered as a pipe is known (for example, refer to patent documents 1).
Japanese Patent Laid-Open No. 11-153019

  However, what is disclosed in Patent Document 1 is that the exhaust passage cross-sectional area of a large-diameter exhaust pipe is not a perfect circle, the passage resistance is increased as compared to a perfect circular pipe of the same cross-sectional area, and the output loss in a high engine speed range. There is a problem that leads to.

  In order to solve such a problem, it is conceivable that the large-diameter exhaust pipe and the small-diameter exhaust pipe are assembled in a single pipe in a parallel state. In this case, the cross-sectional shape of the aggregate portion of the single pipe is changed. There is another problem in that it is necessary to form it in a “gourd shape” and it takes time to form it, and the welding connection process with two parallel pipes in the “gourd shape” becomes complicated, resulting in an increase in cost.

  The present invention has been proposed in view of such a situation, and an object thereof is to provide a novel silencer that solves the above-described problems.

In order to achieve the above object, according to the first aspect of the present invention, a plurality of upstream exhaust pipes for guiding exhaust gas flowing into the silencer body are penetrated in parallel through a support plate provided in the silencer body. The downstream ends of these upstream exhaust pipes are surrounded by the upstream ends of the collecting pipes provided in the silencer body, and the upstream ends of the collecting pipes are spaced from at least a part of these upstream exhaust pipes. The support plate is hermetically fixed to the downstream end surface of the upstream exhaust pipe, and the downstream end of the collecting pipe is connected to the downstream exhaust pipe supported by the silencer body, and the plurality of upstream ends It is characterized in that the downstream end of the exhaust pipe is airtightly gathered in the collecting pipe while being in a parallel state.

According to the first aspect of the present invention, since the downstream ends of the plurality of upstream exhaust pipes are hermetically gathered in the collecting pipe in a parallel state, one exhaust pipe is accommodated in the other exhaust pipe. Compared to the above, the passage resistance of the exhaust gas flowing through the plurality of upstream exhaust pipes can be reduced. In addition, the plurality of upstream exhaust pipes are not directly assembled into a single pipe in a parallel state, but a plurality of pipes that guide the exhaust gas flowing into the silencer body to a support plate provided in the silencer body. The upstream exhaust pipes are supported in parallel, and the downstream ends of the upstream exhaust pipes are surrounded by the upstream ends of the collecting pipes provided in the silencer body, and the upstream ends of the collecting pipes are connected to the upstream exhaust pipes. And a downstream exhaust pipe in which the downstream end of the collecting pipe is supported by the silencer body and is airtightly fixed to a surface of the support plate on the downstream end side of the upstream exhaust pipe. Since it is connected to the pipe, there is no need for a troublesome welding and joining step between the pipes.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on examples of the present invention shown in the accompanying drawings.

  In the accompanying drawings, FIG. 1 is an overall perspective view of an automobile exhaust system equipped with the silencer of the present invention, FIG. 2 is a cutaway perspective view of a secondary silencer, and FIG. 3 is a view taken in the direction of arrow 3 in FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, FIG. 5 is an enlarged sectional view taken along line 5-5 in FIG. 3, and FIG. 6 is an exploded view of the valve body, valve spring and spring receiver of the valve device. FIG. 7 is a schematic view showing the operation of the secondary silencer.

  In FIG. 1, an exhaust system Ex is connected to an exhaust port of an automobile engine, and a primary silencer (prechamber) M1 and a secondary silencer M2 are connected in order from the upstream side to the downstream side of the exhaust system Ex. The exhaust gas flowing through the exhaust system Ex flows through the primary silencer M1 and is temporarily silenced, and further flows through the secondary silencer M2 and is secondarily silenced and discharged to the atmosphere.

  Next, the structure of the secondary silencer M2 according to the present invention will be described in detail with reference to FIGS.

  The secondary silencer M2 includes a silencer body 1, an exhaust introduction pipe 10, a first upstream exhaust pipe 21, a second upstream exhaust pipe 22, and a downstream exhaust pipe 40.

  The silencer main body 1 constitutes a main part of the secondary silencer M2, an outer cylindrical shell 2 having open front and rear end faces, and a front end plate that is airtightly fixed to the front opening of the outer shell 2. 3 and a rear end plate 4 which is airtightly fixed to the rear surface of the opening. The front end plate 3 is located on the front side of the vehicle.

  Inside the silencer body 1, a partition plate 5 is provided substantially in parallel with the front and rear end plates 3, 4, and an upstream chamber U is also provided between the partition plate 5 and the rear end plate 4. A downstream chamber D is defined between the plate 5 and the front end plate 3, and the upstream chamber U has a larger volume than the downstream chamber D. The upstream chamber U is divided into a first chamber U1 and a second chamber U2 by a support plate 6 parallel to the partition plate 5. A plurality of communication holes 7 are opened in the support plate 6, and the first chamber U1 and the second chamber U2 are communicated with each other through the communication holes 7, and between the first chamber U1 and the second chamber U2. Then, the free flow of the exhaust gas can be allowed through the plurality of communication holes 7... And the first chamber U1 and the second chamber U2 substantially function as one upstream chamber U.

  The front end plate 3 and the partition plate 5 are supported by an exhaust introduction pipe 10 extending in the front-rear direction of the silencer body 1 across the front end plate 3 and the partition plate 5. Opened to the outside of the silencer body 1 and connected to an exhaust system that communicates with the exhaust port of the engine E, and the rear end of the exhaust introduction pipe 10 communicates with the first chamber U1 of the upstream chamber U. . Therefore, the exhaust gas discharged by the operation of the engine E flows into the exhaust introduction pipe 10 from the exhaust system Ex, and is led from there to the upstream chamber U in the silencer body 1.

  In the upstream chamber U of the silencer body 1, two first and second upstream exhaust pipes 21 and 22 are accommodated in a parallel state. The first upstream exhaust pipe 21 is bent in a U shape along the axial direction of the silencer body 1, and both end portions thereof are supported by the support plate 6. The upstream half 21u of the first upstream exhaust pipe 21 is disposed so that the inside of the silencer main body 1 is close to the inner surface of the outer shell 2, and the opening end thereof is expanded and opened in the second chamber U2. The downstream half 21d of the first upstream exhaust pipe 21 extends in the front-rear direction in the radial center of the silencer body 1, and its open end is airtightly connected to the inlet of the collective pipe 30, which will be described later. Yes. The upstream half 21u of the first upstream exhaust pipe 21 is supported by a stay 24 that is fixed to the partition plate 5 and extends in a cantilever manner. Further, the second upstream exhaust pipe 22 is formed in a straight shape, and extends in the front-rear direction in the radial center in the silencer body 1 substantially in parallel with the first upstream exhaust pipe 21. The front end is supported by the partition plate 5 and the opening front end communicates with the downstream chamber D. The rear end is supported by the support plate 6 and the opening rear end is a collecting pipe which will be described later. Thirty inlets are connected in an airtight manner.

  A rear end portion, that is, a free end portion of the exhaust introduction pipe 10 and an intermediate portion of the second upstream exhaust pipe 22 are integrally connected by a connecting piece 26 and are reinforced with each other.

  A collective pipe 30 is disposed along the front-rear direction in the central portion in the radial direction of the second chamber U2 of the upstream chamber U. The collective pipe 30 faces the front end, that is, the upstream end, as shown in FIG. The cross-sectional area of the passage is gradually widened and the front end of the opening is airtightly fixed to the rear surface of the support plate 6 by spot welding 31. Further, the rear end, that is, the downstream end, is penetrated and supported by the rear end plate 4 of the silencer body 1 and is airtightly fixed to the rear end plate 4 together with a downstream exhaust pipe 40 described later by bead welding 41. As shown in FIG. 4, the downstream ends of the first and second exhaust pipes 21 and 22 that remain in parallel are communicated with the inlet of the collecting pipe 30, that is, the upstream end thereof. The exhaust gas flowing through the second exhaust pipes 21 and 22 is merged in the collecting pipe 30.

  The communication hole 7 is not formed inside the spot weld 31 of the support plate 6.

  The rear end plate 4 of the silencer body 1 is integrally supported in a cantilever manner with the front end, that is, the upstream end of the straight downstream exhaust pipe 40 communicating with the downstream end of the collecting pipe 30. As shown in FIG. 4, the downstream end of the collecting pipe 30, the upstream end of the downstream exhaust pipe 40, and the rear end plate are airtightly fixed by the bead welding 41 as described above. The downstream exhaust pipe 40 extends outward from the rear end plate 4 of the silencer main body 1, and its downstream end, that is, the rear end, is open to the atmosphere. Therefore, the exhaust gases flowing through the first and second upstream exhaust pipes 21 and 22 are merged in the collecting pipe 30 and then released to the atmosphere through the downstream exhaust pipe 40.

  As shown in FIGS. 2, 3, and 5, the partition plate 5 is provided with an opening 50 that communicates the first chamber U <b> 1 of the upstream chamber U and the downstream chamber D, and this opening 50 is a valve provided therein. The device V is controlled to open and close. Since this valve device V is known in the art (see Japanese Patent No. 3383254) and is not the gist of the present invention, the valve device V will be briefly described as the structure of the valve device V. The exhaust valve is configured to open when the exhaust pressure rises in the high-speed rotation region of E. As shown in FIGS. 5 and 6, the first of the upstream chamber U is fixed to the partition plate 5. A cylindrical valve housing 56 communicating with the chamber U1 and the downstream chamber D, a valve body 51 mounted on the valve housing 56, and a valve spring 52 for biasing the valve body 51 toward the closing side are provided.

  As shown in FIG. 6, the valve body 51 is configured by engaging a pair of spiral plates 51 a and 51 a and joining the semicircular central portions 51 b and 51 b, and the outer peripheral portion thereof is formed. It is seated on the valve seat portion 56 a of the valve housing 56. One spring receiver 54 is provided at the center of the valve body 51. The valve spring 52 is formed of a coil spring, and the body 52 a is supported by one spring receiver 54. Further, the two arm portions 52 b and 52 b of the valve spring 52 are slidably engaged with another spring receiver 55 provided integrally with the valve housing 56, and the valve body 51 is arm portions 52 b and 52 b of the valve spring 52. Is biased toward the valve closing side by the bending reaction force. The valve device V is opened when the exhaust pressure becomes equal to or higher than the valve opening set pressure corresponding to the set load of the valve spring 52 in the valve closing state.

  Thus, when the exhaust gas pressure in the upstream chamber U is below a predetermined value, the valve body 51 is closed by the elastic force of the valve spring 52, and the first upstream chamber U1 and the downstream chamber D are in a shielded state. When the exhaust gas pressure in the upstream chamber U exceeds a predetermined value, the valve body 51 is opened against the elastic force of the valve spring 52, and the first upstream chamber U1 and the downstream side are opened. The room D is maintained in communication.

  As shown in FIG. 2, the front end plate 3 of the silencer body 1 has a portion facing the valve device V bulging outward, and the exhaust gas flows around the device V with little resistance. Therefore, a flow gap is formed.

  Next, the operation of this embodiment will be described.

  Exhaust gas generated by the operation of the engine E flows to the exhaust system Ex. The exhaust gas flowing through the exhaust system Ex is guided to the secondary silencer M2 according to the present invention through the primary silencer M1, and after being silenced, is discharged to the atmosphere.

  By the way, in the low speed operation region including the idling operation and the start operation of the engine E, as shown in FIG. 7A, the combustion pressure of the engine E is low and the pressure of the exhaust gas discharged therefrom is also low. Since the pressure of the exhaust gas flowing into the upstream chamber U through the pipe 10 is weaker than the valve closing spring force of the valve spring 52 of the valve device V, the valve device V maintains the closed state. Therefore, as shown by the arrow in FIG. 7A, all the exhaust gas flowing into the second silencer M2 flows from the exhaust introduction pipe 10 into the upstream chamber U, from the first chamber U1 to the second chamber U2, Thereafter, it flows into the first upstream exhaust pipe 21 formed in a U-shape, passes through the first upstream exhaust pipe 21, passes through the collecting pipe 30 and then passes through the downstream exhaust pipe 40 at the downstream end of the second silencer M2 and is discharged to the atmosphere. Is done. When the exhaust gas flows through the second silencer M2 as described above, the upstream chamber U functions as an expansion chamber, and the exhaust gas is a U-shaped first upstream exhaust pipe. As a result of the flow through 21, the flow path area is reduced and the flow through a long path is made, so that the silencing effect by the second silencer M2 in the low speed rotation region of the engine E can be enhanced.

  On the other hand, when the combustion of the engine E is in a complete explosion state and reaches the high-speed operation range, the combustion pressure increases, and the pressure of the exhaust gas discharged from the engine E also increases, so as shown in FIG. In addition, the pressure of the exhaust gas flowing into the upstream chamber U through the exhaust introduction pipe 10 becomes higher than the valve closing spring force of the valve spring 52 of the valve device V, and the valve device V is maintained in the valve open state. It reaches. Therefore, as shown by an arrow in FIG. 7B, a part of the exhaust gas flowing into the first chamber U1 of the upstream chamber U from the exhaust introduction pipe 10 passes through the plurality of communication holes 7 of the support plate 6. The second chamber U2 of the upstream chamber U and from there flows into the first upstream exhaust pipe 21 while its remaining part flows into the downstream chamber D through the valve device V of the partition plate 5, and from there 2 into the upstream exhaust pipe 22. The exhaust gas that has passed through the first and second upstream exhaust pipes 21 and 22 merges in the collecting pipe 30, and the combined exhaust gas passes through the downstream exhaust pipe 40 and is discharged to the atmosphere. When the exhaust gas flows through the second silencer chamber M2 as described above, the upstream chamber U and the downstream chamber D function as expansion chambers, and the exhaust gas is the first and second upstream exhaust gases. By flowing through the pipes 21, 22, the flow area is large and a part of the flow passes through a short path, so that the exhaust resistance of the silencer in the high-speed rotation region of the engine E can be reduced.

As described above, since the downstream ends of the first and second upstream exhaust pipes 21 and 22 are airtightly gathered in the collecting pipe 30 in a parallel state, as shown in Patent Document 1, one upstream side The passage resistance of the exhaust gas flowing through the upstream exhaust pipe can be greatly reduced as compared with the exhaust pipe that is housed in the other upstream exhaust pipe. The first and second upstream exhaust pipes 21 and 22 are not directly assembled into a single pipe in a parallel state, but are attached to the support plate 6 provided in the silencer body 1 in the silencer body 1. A plurality of upstream exhaust pipes 21 and 22 that guide exhaust gas flowing into the pipe are supported in parallel, and downstream ends of the upstream exhaust pipes 21 and 22 are provided in the silencer body 1. Surrounding by the upstream end, the upstream end of the collecting pipe 30 is spaced from at least a part of the upstream exhaust pipes 21, 22, on the downstream end side of the upstream exhaust pipes 21, 22 in the support plate 6. Since the downstream end of the collective pipe 30 is connected to the downstream exhaust pipe 40 supported by the silencer body 1, it is not necessary to perform a troublesome welding joining process between the pipes. .

  As mentioned above, although the Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the scope of the present invention.

  For example, in the above-described embodiment, the case where the present invention is implemented in the second silencer M2 has been described. However, this may be implemented in the first silencer M1, and in the above-described embodiment, upstream sides that are parallel to each other. Although the case where the exhaust pipe is configured by the first and second upstream exhaust pipes 21 and 22 each having been described has been described, it may be configured by a plurality of each.

Overall perspective view of an automobile exhaust system equipped with the silencer of the present invention Broken perspective view of secondary silencer 3 arrow view of FIG. Sectional view along line 4-4 in FIG. Enlarged sectional view taken along line 5-5 in FIG. Exploded perspective view of valve body, valve spring and spring receiver of valve device Schematic showing the operation of the secondary silencer

Explanation of symbols

1 ... silencer body 6 ... support plate 21 upstream exhaust pipe (first upstream exhaust pipe)
22: Upstream exhaust pipe (second upstream exhaust pipe)
30 ... Collective pipe 40 ... Downstream exhaust pipe

Claims (1)

A plurality of upstream exhaust pipes (21, 22) for guiding the exhaust gas flowing into the silencer body (1) are passed through and supported in a support plate (6) provided in the silencer body (1). The downstream ends of the upstream exhaust pipes (21, 22) are surrounded by the upstream end of the collecting pipe (30) provided in the silencer body (1), and the upstream end of the collecting pipe (30) And at least a part of the side exhaust pipe (21, 22), and is airtightly fixed to the downstream end surface of the upstream side exhaust pipe (21, 22) in the support plate (6) , and the collecting pipe The downstream end of (30) is connected to the downstream exhaust pipe (40) supported by the silencer body (1), and the downstream ends of the plurality of upstream exhaust pipes (21, 22) remain in a parallel state. It is characterized in that the assembly pipe (30) is assembled in an airtight manner. Vessel.

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