JP2005105918A - Engine exhaust gas noise suppressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to suppress a resonance noise without providing a resonance muffling chamber in a main muffler, to spare the resonance muffler in the main muffler so as to enlarge the volume of an expansion chamber contributed to noise deadening in the main muffler by the volume, and improve the sound-deadening characteristic of the main muffler, in an exhaust gas noise suppressor installing the main muffler at the downstream side of the exhaust pipe introducing the exhaust gas exhausted from the engine. <P>SOLUTION: The exhaust gas noise suppressor is connected to an exhaust gas port of the engine E, and the main muffler MM is connected to the downstream side of the exhaust gas pipe EP to introduce the exhaust gas exhausted from the engine E. A resonance muffler MR is installed in the exhaust pipe EP further upstream than the main muffler MM. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust silencer for an engine that suppresses exhaust noise generated from an exhaust pipe connected to an engine for automobiles or the like.

2. Description of the Related Art Conventionally, an exhaust silencer for an automobile engine has an exhaust pipe connected to the exhaust port of the engine extending in the front-rear direction below the vehicle body, and a silencer is provided downstream of the exhaust pipe so that the exhaust flowing through the exhaust pipe is exhausted. Gas exhaust noise is suppressed (for example, see Patent Document 1).
JP-A-2001-82139

  By the way, in an exhaust system for an automobile engine, in which the engine is mounted on the front part of the vehicle body, the exhaust pipe of the exhaust pipe device has its front end side, that is, the upstream side connected to the engine on the front part of the vehicle body. Since the lower part of the vehicle body is extended in the front-rear direction and the silencer is usually connected to the rear end side, that is, the downstream side, the length of the exhaust pipe extending from the engine to the silencer becomes longer.

  However, when the length of the exhaust pipe from the engine to the silencer becomes longer, the natural frequency of the exhaust pipe matches the frequency of the pulsation of the exhaust gas flowing through the exhaust pipe (engine speed). The frequency of the occurrence of the peak increases, and resonance tends to occur in this part, especially when the exhaust pipe is branched into two exhaust pipes in the middle and a silencer is provided for each of them. Since the two silencers are arranged apart from each other in the width direction of the vehicle body, the length of the exhaust pipe between the engine and the silencer is further increased, and the frequency of occurrence of the resonance phenomenon is increased at this portion. is there.

  The present invention has been proposed in view of such circumstances, and an object of the present invention is to provide a novel engine exhaust silencer that solves the above-described problems and can reduce exhaust noise as much as possible. .

  In order to achieve the above object, the invention of claim 1 is an exhaust silencer comprising a main silencer connected to an exhaust port of an engine and downstream of an exhaust pipe for guiding exhaust gas exhausted from the engine. In the above, a resonance type silencer is provided in the exhaust pipe upstream of the main silencer.

  In order to achieve the above object, the invention according to claim 2 is directed to an auxiliary muffler in order from an upstream side to a downstream side of an exhaust pipe that is connected to an exhaust port of an engine and guides exhaust gas discharged from the engine. An exhaust silencer for an engine, in which an air silencer and a main silencer are provided at an interval, is characterized in that a resonance silencer is provided in an exhaust pipe between the main silencer and the auxiliary silencer.

  In order to achieve the above-mentioned object, the invention according to claim 3 is directed to the left and right downstream exhausts via the branching portion on the downstream side of the exhaust pipe connected to the exhaust port of the engine and guiding the exhaust gas exhausted from the engine. In the exhaust silencer for an engine, the main silencer is provided in each of the left and right downstream exhaust pipes, and the resonance type silencer is provided in the upstream exhaust pipe upstream from the branch portion. It is characterized by that.

  In order to achieve the above object, the invention of claim 4 is characterized in that, in the invention of claim 3, an auxiliary silencer is provided in the upstream exhaust pipe upstream of the resonance silencer. Yes.

  In order to achieve the above object, the invention according to claim 5 is the invention according to claim 1, 2, 3, or 4, wherein the resonance silencer is a double pipe comprising an inner pipe and an outer pipe. The inner tube and the outer tube are communicated with each other, and an annular resonance type silencing chamber is formed between them.

  According to the first aspect of the present invention, since the resonance silencer is provided in the exhaust pipe upstream of the main silencer, resonance noise can be suppressed without providing a resonance silencer chamber in the main silencer. In addition, since it is not necessary to provide a resonance silencer in the main silencer, the volume of the expansion chamber contributing to the silence in the main silencer can be increased, and the silencer performance of the main silencer itself can be increased. In addition, the structure can be simplified.

  According to the second aspect of the present invention, since the resonance silencer is provided in the exhaust pipe between the main silencer and the auxiliary silencer, no resonance silencer chamber is provided in the main silencer and / or the auxiliary silencer. Therefore, the volume of the expansion chamber that contributes to the silencing in the main silencer and / or the auxiliary silencer can be increased, and the silencing performance can be increased, and the structure of the chamber can be simplified. Can be

  According to the third aspect of the present invention, the main silencer is provided in each of the left and right downstream exhaust pipes branched via the branch part on the downstream side of the exhaust pipe, and the upstream side upstream of the branch part. Since the resonance silencer is provided in the side exhaust pipe, the resonance noise can be suppressed without providing the resonance silencer in the main silencer, and it is not necessary to provide the resonance silencer in the main silencer. Therefore, the volume of the expansion chamber contributing to the silencing can be increased correspondingly, the silencing performance of the main silencer can be enhanced, and the structure thereof can be simplified.

  According to the fourth aspect of the present invention, since the auxiliary silencer is provided in the upstream exhaust pipe upstream from the resonance type silencer, the resonance silencer chamber is provided in the main silencer. Resonance noise can be suppressed without providing a noise reduction chamber, and it is not necessary to provide a resonance silencer chamber in the main silencer and / or the auxiliary silencer. The volume of the main silencer and / or the auxiliary silencer can be increased, and the structure thereof can be simplified.

  According to a fifth aspect of the present invention, in the first, second, third or fourth aspect, the silencer body of the resonance type silencer is a double pipe comprising an inner tube and an outer tube. The inner pipe and the outer pipe are communicated with each other, and an annular resonance type silencer chamber is formed between them. Therefore, when a resonance type silencer is provided in the exhaust pipe, the resonance type silencer It can be formed compactly and hardly interferes with its peripheral equipment.

  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.

  First, the first embodiment of the present invention will be described with reference to FIGS.

  1 is an overall plan view of an exhaust silencer for an engine of the present invention, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is an enlarged sectional view taken along line 3-3. is there.

  The first embodiment is a case where the present invention is applied to an exhaust system of a traveling engine E of an automobile. In FIG. 1, an exhaust port of the traveling engine E mounted on the front portion of the vehicle body B in FIG. A front end of an exhaust pipe EP for purifying, silencing and releasing the exhaust gas discharged from the engine E to the atmosphere is connected. The exhaust pipe EP is supported at the lower part of the vehicle body B of the automobile and extends long along the front-rear direction of the vehicle body B. The lower end of the exhaust pipe EP is opened to the atmosphere at the rear part of the vehicle body B.

  The exhaust pipe EP has an upstream end connected to an exhaust port of the engine E, extends in the front-rear direction of the vehicle body B and extends rearward, and a downstream end of the upstream exhaust pipe 1. The two left and right downstream exhaust pipes 2L and 2R are connected via a branch pipe 3 serving as a branch portion and are spaced apart in the width direction of the vehicle body B. The left exhaust pipe 2L is a right exhaust. It is formed longer than the tube 2R. A single upstream exhaust pipe 1 is provided with an exhaust catalyst CA and an auxiliary silencer MA (pre-chamber) in series at intervals from the upstream side to the downstream side, and further, the auxiliary silencer MA and the branch pipe 3 is provided with a resonance silencer MR (side branch silencer). The upstream ends of two main silencers MM and MM that make a pair are connected to the downstream ends of the left and right downstream exhaust pipes 2L and 2R, respectively. Are connected to tail pipes 5 and 5, respectively.

  The auxiliary silencer MA and the left and right main silencers MM, MM are elastically supported on the lower surface of the vehicle body B via front and rear support means SF, SR provided with elastic members.

  Note that the exhaust catalyst CA, the auxiliary silencer MA, and the left and right main silencers MM, MM are all conventionally known, and thus detailed description thereof is omitted.

  As shown clearly in FIGS. 2 and 3, a resonance silencer MR (side branch silencer) according to the present invention includes a hollow cylindrical inner tube 10 having both ends opened and the inner tube 10 concentrically. A hollow cylindrical outer tube 11 which is also open at both ends and is surrounded by a double tube, and between the inner tube 10 and the outer tube 11, an annular resonance silencer chamber having a dead end on the downstream side between the inner tube 10 and the outer tube 11. 12 is formed. The outer pipe 11 has a larger diameter than the upstream exhaust pipe 1. The front and rear ends of the upstream exhaust pipe 1 are airtightly welded to the outer peripheral surfaces of the upstream half 1u and the downstream half 1d of the upstream half. In addition, the inner tube 10 has a pair of communication ports 13 formed at positions facing the front in the radial direction, and the inner tube 11 communicates with the resonance silencer chamber 12 through the communication holes 13. Further, the front end or upstream end of the inner pipe 11 communicates with the upstream half 1 u of the upstream exhaust pipe 1 and the resonance silencer chamber 12, and the rear end or downstream end thereof is the downstream half of the upstream exhaust pipe 1. 1d, and is overlapped with the upstream end of the downstream half 1d and the downstream end of the outer tube 11, and is hermetically welded. The outer peripheral surface of the upstream end of the inner tube 10 is slidably fitted to the inner peripheral surface of the upstream end of the outer tube 11 via a mesh ring 14 provided in the resonance silencer chamber 12. Heat extension with respect to the pipe 11 can be allowed, and a part of the exhaust gas flowing through the upstream side exhaust pipe 1 flows around the resonance silencer chamber 12 through the communication port 13. .

  The inner tube 10 may be provided with a plurality of small holes such as punching holes in place of the communication port 13, and when the inner tube 10 is short, a means for absorbing thermal elongation. Is unnecessary.

  Next, the operation of the first embodiment will be described.

  Now, according to the operation of the engine E, the exhaust gas discharged therefrom flows into the exhaust pipe EP. The exhaust gas flowing through the exhaust pipe EP flows to the exhaust catalyst CA, the auxiliary silencer MA, and the resonance type silencer MR, and further flows through the branch pipe 3 and is divided into a pair of left and right main silencers MM and MM. It is discharged to the atmosphere via the tail pipes 5 and 5. In the exhaust catalyst CA, harmful components such as HC, CO, and NOx contained in the exhaust gas are purified and removed, and in the auxiliary silencer MA, the exhaust noise is supplementarily primarily silenced. As will be described in detail later, the silencer MR effectively attenuates the resonance vibration generated in the long exhaust pipe EP, and further the main silence of the exhaust sound is performed in the pair of main silencers MM and MM.

  By the way, the exhaust pipe EP extends long in the front-rear direction of the vehicle body B from the engine E at the front part of the vehicle body B to the main silencer MM, MM at the rear part of the vehicle body B, and has a long pipe length. Since devices such as CA and auxiliary silencer MA are connected, the long exhaust pipe EP between the engine E and the main silencer MM is likely to resonate, that is, the natural frequency of the exhaust pipe EP and the exhaust pipe. The frequency of exhaust gas flowing through the EP matches the frequency of exhaust gas, and the frequency at which the exhaust noise reaches a peak increases. As a result, exhaust noise tends to increase. Silencer) By diverting a part of the exhaust pipe gas flowing through the MR into the resonance silencer chamber 12, the resonance vibration can be attenuated, and the resonance noise of the exhaust gas flowing through the exhaust pipe EP is suppressed as much as possible. be able to.

  In particular, as shown in the first embodiment, the exhaust pipe EP branches from the single upstream exhaust pipe 1 into two left and right downstream exhaust pipes 2L and 2R, and these downstream exhaust pipes When the main silencers MM and MM are respectively provided in 2L and 2R, the pair of main silencers MM and MM are disposed apart from each other in the width direction of the vehicle body B, so that the engine E and the main silencer MM, The length of the exhaust pipe EP leading to the MM becomes longer and resonance easily occurs in this portion. In such a case, the effect of suppressing the exhaust noise due to the damping action of the resonance vibration becomes more prominent.

  By the way, if each main silencer MM itself forms a resonance silencer chamber in the main silencer MM in order to suppress resonance noise, the expansion chamber in the main silencer MM (the larger the volume, the more the silencer performance). However, according to the first embodiment, the main silencer MM is not provided with a resonance silencer chamber. In both cases, since the resonance noise can be suppressed, the inconvenience can be solved, and the exhaust noise can be largely suppressed as a whole, and the increase in size and cost of each main silencer MM can be reduced.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  3 is an overall plan view of the exhaust silencer device of the engine E, and FIG. 4 is an enlarged cross-sectional view taken along line 4-4 of FIG. 3, in which the same elements as those of the first embodiment are the same. A sign is attached.

  This second embodiment is different from the first embodiment in the configuration of a resonance silencer (side branch silencer) MR. The resonance silencer MR is composed of a T-shaped pipe 100, and is connected to a midway of the upstream side exhaust pipe 1, and a straight portion 100a, and an upright portion 100b that stands up at a substantially right angle from the middle of the straight portion 100a. The free end of the upright portion 100b is sealed. The straight portion 100 a constitutes a part of the upstream side exhaust pipe 1, and the upright portion 100 b functions as the resonance silencer chamber 12.

  A part of the exhaust gas flowing through the upstream side exhaust pipe 1 flows around the resonance silencer chamber 12 of the resonance silencer MR, whereby the auxiliary silencer MA and the pair of main silencers MM are the same as in the first embodiment. The resonance vibration generated in the long upstream exhaust pipe 1 connecting the two can be attenuated, and the exhaust noise caused by the resonance can be effectively suppressed.

  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 applied to an exhaust system of an automobile engine has been described. However, it is needless to say that the present invention can also be applied to an exhaust system of another engine. Although a case where a pair of main silencers is provided in the pipe has been described, a single main silencer may be provided in the exhaust pipe, and in the embodiment, the resonance silencer is provided in the exhaust pipe. Although one auxiliary silencer is provided on the upstream side, a plurality of auxiliary silencers may be provided or omitted. Further, the resonance silencer formed in the resonance silencer may be formed in any shape as long as it has an intended function.

Overall plan view of exhaust silencer device for engine E (first embodiment) FIG. 1 is an enlarged sectional view taken along line 2-2 of FIG. 1 (first embodiment). Expanded sectional view taken along the second line 3-3 (first embodiment) Overall plan view of exhaust silencer device for engine E (second embodiment) FIG. 4 is an enlarged sectional view taken along line 5-5 (second embodiment).

Explanation of symbols

1... Upstream exhaust pipes 2L, 2R... Left and right downstream exhaust pipes 3... Branch part (branch pipe)
10 .... Inner pipe 11 ... Outer pipe 12 ... Resonance silencer chamber E ... Engine EP ... Exhaust Tube MA ····· Auxiliary silencer MM ···················································

Claims (5)

  In the exhaust silencer, which is connected to the exhaust port of the engine (E), and is provided with a main silencer (MM) on the downstream side of the exhaust pipe (EP) for guiding the exhaust gas exhausted from the engine (E), An exhaust silencer for an engine, characterized in that a resonance silencer (MR) is provided in an exhaust pipe (EP) upstream of the main silencer (MM). An auxiliary muffler (MA) and a main silencer are connected to an exhaust pipe (EP) connected to an exhaust port of the engine (E) and leading to exhaust gas discharged from the engine (E) from the upstream side to the downstream side. In an engine exhaust silencer that is provided with a silencer (MM) at an interval,
An exhaust silencer for an engine, wherein a resonance silencer (MA) is provided in an exhaust pipe (EP) between the main silencer (MM) and the auxiliary silencer (MA). Connected to the exhaust port of the engine (E), the downstream side of the exhaust pipe (EP) that guides the exhaust gas discharged from the engine (E) is connected to the left and right downstream side exhaust pipes (2L) via the branch part (3). , 2R), and an exhaust silencer for an engine, in which a main silencer (MM) is provided in each of the left and right downstream exhaust pipes (2L, 2R),
An exhaust silencer for an engine, characterized in that a resonance silencer (MR) is provided in an upstream exhaust pipe (1) upstream of the branch part (3).   The engine exhaust silencer according to claim 3, wherein an auxiliary silencer (MA) is provided in the upstream exhaust pipe (1) upstream of the resonance silencer (MR). The resonance muffler (MR) is composed of a double pipe composed of an inner pipe (10) and an outer pipe (11), and the inner pipe (10) and the outer pipe (11) communicate with each other, The engine exhaust silencer according to claim 1, 2, 3, or 4, wherein an annular resonance silencer (12) is formed between them.

Images