JP2004316564A - Muffler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a muffler for realizing miniaturization and improving a muffling function with a simple structure. <P>SOLUTION: The muffler is provided with at least an exhaust pipe directly or indirectly connected with an exhaust port of an internal combustion engine, a finisher arranged on an extension line of the exhaust pipe in a downstream side in a exhausting direction, and a muffling mechanism disposed between the exhaust pipe and the finisher. In the muffling mechanism, a plurality of cylindrical bodies with respectively different diameters are approximately concentrically disposed and bottom parts are provided for closing prescribed end faces to form exhaust passages and expansion spaces. An exhaust pressure control valve is provided on an end part of the exhaust pipe to easily regulate valve-opening pressure from a finisher side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a muffler for exhaust of an internal combustion engine mounted on an automobile or the like.
[0002]
[Prior art]
As a conventional technique relating to a muffler (silencer), Patent Document 1 discloses a casing, a gas suction pipe to the casing, a pipe incorporated in the casing, a diaphragm, a support elastic body, a piston rod, and a pressure connection portion. In a muffler comprising an overpressure vessel as an operating mechanism, a valve closing element attached to a piston rod, and a pressure conduit for transmitting a total pressure of gas to an overpressure side of the diaphragm, a plurality of operation vessels separated by a diaphragm are provided. Are disclosed in which each diaphragm is supported by an elastic body, each chamber has a pressure connection, and another pressure conduit carries static gas pressure to the low pressure side of the diaphragm. Therefore, according to Patent Document 1, it is described that a silencer having a variable attenuation characteristic curve can be provided without providing an external control device.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 9-166010
[Problems to be solved by the invention]
However, as shown in FIG. 1, the muffler disclosed in Patent Document 1 has a plurality of pipes 3 through which gas flows between the inside and outside of the casing 2 and between the three expansion chambers 21, 23, and 35. Since 1, 3.2, 3.3, and 3.4 are arranged in parallel, there is a problem that the entire apparatus becomes large. Further, since the exhaust pressure cannot be easily adjusted from the outside, it is not possible to match the driver's favorite state, and there is a problem that the driving must be continued while being uncomfortable.
[0005]
Accordingly, an object of the present invention is to provide a muffler that achieves downsizing and improves a muffling function with a simple structure.
[0006]
[Means for Solving the Problems]
Therefore, the present invention provides an exhaust pipe that is directly or indirectly connected to an exhaust port of an internal combustion engine, a finisher disposed on the extension line of the exhaust pipe on the downstream side in the exhaust direction, and the exhaust pipe and the finisher. A silencer with an exhaust pressure adjusting valve having at least a silencing mechanism provided between the exhaust pipe and a plurality of small exhaust holes formed in a peripheral edge of a downstream end portion of the exhaust pipe; A first cylindrical portion having a one-sided cylindrical shape having a downstream closed bottom surface portion fixed to the peripheral edge of the exhaust pipe on the downstream side in the exhaust direction of the exhaust small hole, and being substantially concentric with the exhaust pipe; A second cylindrical portion having an upstream closed bottom surface portion fixed to the peripheral edge of the exhaust pipe on the upstream side in the exhaust direction of the exhaust small hole, having a diameter larger than the first cylindrical portion by a predetermined value, and having an open cylindrical shape; Overlap with the first cylindrical part in a predetermined range A downstream end is connected to the finisher, and a third cylindrical portion having both ends open cylindrical and having a diameter smaller than the first cylindrical portion by a predetermined value, and a predetermined value smaller than the third cylindrical portion. An upstream enlarged diameter portion having a diameter and being internally provided in the third cylindrical portion and having a distal end fixed to an inner peripheral surface of the first cylindrical portion; and a distal end located on the inner peripheral surface of the finisher. A fourth cylindrical portion having a downstream enlarged-diameter portion to be fixed, a downstream exhaust hole formed in the downstream enlarged-diameter portion, and a silencer case externally provided to the second cylindrical portion. Wherein the muffling mechanism is defined by the first cylindrical portion and the second cylindrical portion, and a first exhaust passage communicating with the small exhaust hole, the second cylindrical portion and the muffler are provided. A first expansion space defined between the first cylindrical portion and the first cylindrical portion; A second exhaust passage defined by the third cylindrical portion and communicating with the first expansion space; and a second exhaust passage defined by the third cylindrical portion and the fourth cylindrical portion; A third exhaust passage communicating with the exhaust passage and the downstream exhaust hole, and a third exhaust passage defined inside the fourth cylindrical portion, wherein the downstream exhaust hole is open and communicates with the opening of the finisher. 2 expansion space.
[0007]
Further, at the downstream end of the exhaust pipe in the exhaust direction, an exhaust pressure adjusting valve for short-circuiting the exhaust pipe and the finisher when the pressure of the exhaust gas becomes equal to or higher than a predetermined value is provided. It is preferable that the exhaust pipe communicates with the opening of the finisher via the second expansion space by opening the valve.
[0008]
Further, a shield externally provided to the second cylindrical portion for shutting off the second exhaust passage and the first expansion chamber and connecting the first exhaust passage and the second exhaust passage. Preferably, a fifth cylindrical portion having a bottom portion and defining a fourth exhaust passage communicating between the first exhaust passage and the first expansion chamber is provided between the second cylindrical portion and the second cylindrical portion. .
[0009]
Furthermore, the exhaust pressure regulating valve opens and closes the end of the exhaust pipe, and presses the valve body toward the end of the exhaust pipe, the valve body having a convex shape protruding upstream in the exhaust direction. It is desirable to have a spring and a pressing force adjusting mechanism for adjusting the pressing force by the spring.
[0010]
Further, the pressing force adjusting device includes a holding unit that holds one end of the spring, and a rotating unit that adjusts the pressing force by moving the holding unit with respect to the valve body, and the rotating unit includes: Desirably, it is located on the extension line and is adjustable from the opening of the finisher.
[0011]
Further, it is preferable that the downstream exhaust holes are formed at predetermined intervals around a periphery of the downstream enlarged diameter portion of the fourth cylindrical portion. Further, the downstream exhaust hole may be a square hole that opens on the upstream side to the third exhaust passage, or a streamline hole that opens on the upstream side to the third exhaust passage. Good thing.
[0012]
Furthermore, a small expansion space is provided upstream of the first exhaust passage and between a downstream closed bottom surface of the first cylindrical portion and an upstream closed side surface of the second cylindrical portion. Is desirably formed.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
A muffler 1 shown in FIG. 1 includes an exhaust pipe 2 directly or indirectly connected to an exhaust port of an internal combustion engine (not shown), a finisher 3 disposed on an extension of the exhaust pipe 2 on the downstream side in the exhaust direction, A muffling mechanism 4 provided between the exhaust pipe 2 and the finisher 3; and a muffling mechanism 4 provided at a downstream end of the exhaust pipe 2 in the exhaust direction A. It is at least constituted by an exhaust pressure adjusting valve 5 for short-circuiting between the exhaust pipe 2 and the finisher 3.
[0015]
The muffler 1 is further disposed substantially concentrically with the exhaust pipe 2 and at a plurality of small exhaust holes 6 formed in the periphery of the exhaust pipe 2 near the exhaust pressure regulating valve 5. A first cylindrical portion 8 having a downstream closed bottom portion 7 fixed to the peripheral edge of the exhaust pipe 2 on the downstream side in the exhaust direction A of the hole 6 and having a cylindrical shape with one opening, and arranged substantially concentrically with the exhaust pipe 2. An upstream closed bottom surface portion 9 fixed to a peripheral edge of the exhaust pipe 2 on the upstream side in the exhaust direction A of the exhaust small hole 6, and having a diameter larger by a predetermined value than the first cylindrical portion 2. The second cylindrical portion 10 having an open cylindrical shape overlaps the first cylindrical portion 8 in a predetermined range, and a downstream end portion 11 is connected to the finisher 3, so that the second cylindrical portion 10 is smaller than the first cylindrical portion 8. A third cylindrical portion 12 having a smaller diameter by a predetermined value and having both ends open and cylindrical; An upstream-side enlarged portion 14 having a small diameter, which is provided inside the third cylindrical portion 12 and whose tip 13 is fixed to the inner peripheral surface 81 of the first cylindrical portion 8, A fourth cylindrical portion 18 having a downstream enlarged diameter portion 16 fixed to the inner peripheral surface 31 of the finisher 3, and a downstream exhaust hole 17 formed in the downstream enlarged diameter portion 16; At least a silencer case 19 provided outside the second cylindrical portion 10.
[0016]
Further, as shown in FIGS. 2A and 2B, the downstream enlarged diameter portion 16 located inside the finisher 3 is provided at the predetermined distance along the circumferential direction of the outer peripheral surface. Each of the downstream exhaust holes 17 is formed in a substantially rectangular shape, and is projected outward in the radial direction such that an opening 17a is opened on the third exhaust passage 23 side. It is formed as follows. As a result, the struck portion serves as the guide portion 17b so that the air can be efficiently exhausted to the rear of the finisher 3.
[0017]
With the above configuration, the muffling mechanism 4 is defined by the first cylindrical portion 8 and the second cylindrical portion 10, the first exhaust passage 20 communicating with the small exhaust hole 6, and the second exhaust passage 20. A first expansion space 21 defined between the cylindrical portion 10 and the silencer case 19 and opening the first exhaust passage 20; the first cylindrical portion 8 and the third cylindrical portion 12; , And a second exhaust passage 22 communicating with the first expansion space 21, and the second exhaust passage defined by the third cylindrical portion 12 and the fourth cylindrical portion 18. A third exhaust passage 23 that communicates with the downstream-side exhaust hole 17, and an inside of the fourth cylindrical portion 18, wherein the downstream-side exhaust hole 17 is opened and the opening of the finisher 3 is opened. 32 and communicates with the exhaust pipe 2 by opening the exhaust pressure regulating valve 5. It constituted by a second expansion space 24.
[0018]
Accordingly, when the exhaust pressure regulating valve 5 is closed, the exhaust gas that has reached the exhaust pipe 2 flows from the exhaust small hole 6 to the small expansion space 25 formed on the upstream side of the first exhaust passage 20. , Where the first expansion is performed. Then, the second expansion is performed by being discharged from the first exhaust passage 20 to the first expansion space 21, and further, passes through the second and third exhaust passages 22 and 23 to form a wake. The third expansion is performed by being released from the side exhaust hole 17 to the second expansion space 24 and the external space. As described above, since the expansion can be performed a plurality of times, the exhaust gas is efficiently silenced.
[0019]
The exhaust pressure regulating valve 5 opens and closes an end of the exhaust pipe 2, and has a convex valve body 51 protruding in the upstream direction in the exhaust direction A; It is constituted by a spring 52 that presses toward the end, and a pressing force adjusting mechanism 60 that adjusts the pressing force by the spring 52.
[0020]
Further, the pressing force adjusting mechanism 60 includes a holding portion 61 that holds one end of the spring 52, and a rotating portion 62 that moves the holding portion 61 with respect to the valve body 51 to adjust the pressing force. Since the rotating portion 62 is positioned on an extension of the center line of the silencer 1, the rotating portion 62 can be rotated from the opening 32 of the finisher 3, and the pressing force can be adjusted. Is what you do. Thereby, the valve opening pressure of the exhaust pressure adjusting valve can be adjusted.
[0021]
More specifically, an example will be described. A frame body 63 for fixing a rod 64 to which the rotating portion 62 is screwed is fixed inside the exhaust pipe 2, and the valve body 51 and the bottomed cylindrical shape are fixed to the rod 64. Is slidably fitted. Then, a spring 52 is arranged between the valve body 51 and the holding part 61, and the holding part 61 is fixed to the rod 64 by a nut serving as a rotating part 62.
[0022]
Accordingly, when the exhaust pressure applied to the valve body 51 becomes higher than the pressing force determined by the spring 52, the valve body 51 is separated from the end of the exhaust pipe 2, and the exhaust pipe 2 and the finisher 3 are separated from the second expansion space. Short-circuited through the wire 24 reduces the airflow resistance.
[0023]
The pressing force of the spring 52 is increased by rotating the rotating portion (nut) 62 screwed to the rod 64 to move the holding portion 61 to the valve body 51 side. It can be lowered by moving 61 in the direction away from valve body 51. As described above, the strength of the spring 52 that presses the valve body 51 can be changed by rotating the rotating part (nut) 62, so that the exhaust pressure required for opening the valve by the valve body 51 changes. That can be done.
[0024]
The silencer 1 according to the second embodiment is, for example, the one shown in FIG. The silencer 1 is provided outside the second cylindrical portion 10 to shut off the second exhaust passage 22 and the first expansion chamber 21, and to connect the first exhaust passage 20 to the first A fourth exhaust passage having a shielding bottom portion 40 connecting the second exhaust passage 22 and the first exhaust passage 20 and the first expansion chamber 21 between the second exhaust passage 22 and the second cylindrical portion 10; A fifth cylindrical portion 41 defining 43 is provided. Further, a branch space 42 to the second exhaust passage 22 and the fourth exhaust passage 43 is defined at the outlet end of the first exhaust passage 20.
[0025]
Thus, the silencer 1 according to the first embodiment is a simple expansion type, whereas the muffler 1 according to the second embodiment is different from the first expansion space in the first embodiment. This is a resonance tube type having a resonance space 21. In the second embodiment, the same portions as those in the first embodiment or portions having similar effects are denoted by the same reference numerals, and description thereof is omitted.
[0026]
In the downstream enlarged diameter portion 16 shown in FIGS. 4A and 4B, the shape of the downstream exhaust holes 17 arranged at predetermined intervals along the circumferential direction of the outer peripheral surface is formed in a streamlined manner. It is characterized by the following. As a result, the portion projected outward in the radial direction becomes the streamlined guide portion 17d, and the exhaust gas flowing from the opening portion 17c opened toward the third exhaust passage 23 can be exhausted to the rear of the finisher 3 more efficiently. It is something that will be.
[0027]
【The invention's effect】
As described above, according to the present invention, the silencing mechanism provided between the exhaust pipe and the finisher is configured such that a plurality of cylindrical cylinders having different diameters are arranged substantially concentrically and a predetermined end surface is closed. By providing the bottom to define the exhaust passage and the expansion space, the muffler itself can be reduced in size and the muffling effect can be improved.
[0028]
Further, since the exhaust pressure regulating valve is provided at the end of the exhaust pipe and at a position facing the opening of the finisher, the valve opening pressure of the exhaust pressure regulating valve can be easily adjusted from the opening side of the finisher. Is what you can do.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a muffler according to a first embodiment of the present invention.
FIGS. 2A and 2B are explanatory views of a downstream enlarged diameter portion of a fourth cylindrical portion provided inside a finisher, wherein FIG. 2A is a front view and FIG.
FIG. 3 is a sectional view of a muffler according to a second embodiment of the present invention.
4A and 4B are explanatory views of a downstream enlarged diameter portion of a fourth cylindrical portion according to another embodiment, wherein FIG. 4A is a front view thereof, and FIG. 4B is a sectional view thereof.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Muffler 2 Exhaust pipe 3 Finisher 4 Muffler 5 Exhaust pressure control valve 6 Exhaust small hole 7 Downstream shielding bottom 8 First cylindrical part 9 Upstream shielding bottom 10 Second cylindrical part 12 Third cylindrical part 14 Upstream Side enlarged diameter portion 16 Downstream enlarged diameter portion 17 Downstream exhaust hole 18 Fourth cylindrical portion 19 Silencer case 20 First exhaust passage 21 First expansion space 22 Second exhaust passage 23 Third exhaust passage 24 Second expansion space 40 Shielding bottom 41 Fifth cylindrical part 42 Branch space 43 Fourth exhaust passage 51 Valve body 52 Spring 60 Pressing force adjusting mechanism 61 Holding part 62 Rotating part (nut)
63 Frame 64 Rod

Claims (9)

An exhaust pipe connected directly or indirectly to an exhaust port of an internal combustion engine, a finisher disposed on the extension of the exhaust pipe on the downstream side in the exhaust direction, and a silencing mechanism provided between the exhaust pipe and the finisher And a silencer with an exhaust pressure regulating valve having at least
A plurality of exhaust holes formed in the periphery of the downstream end of the exhaust pipe,
A first cylindrical portion having a one-sided cylindrical shape, which is disposed substantially concentrically with the exhaust pipe and has a downstream closed bottom surface portion fixed to a peripheral edge of the exhaust pipe on the downstream side in the exhaust direction of the exhaust small holes;
The exhaust pipe has an upstream closed bottom surface that is substantially concentric with the exhaust pipe and is fixed to a peripheral edge of the exhaust pipe on the upstream side in the exhaust direction of the exhaust small hole, and has a diameter larger than the first cylindrical part by a predetermined value. A second cylindrical part having a one-sided cylindrical shape,
A third cylindrical portion which is overlapped with the first cylindrical portion in a predetermined range, has a downstream end connected to the finisher, and has a both-end open cylindrical shape having a smaller diameter than the first cylindrical portion by a predetermined value; When,
An upstream enlarged diameter portion having a diameter smaller than the third cylindrical portion by a predetermined value, being provided in the third cylindrical portion, and having a tip fixed to an inner peripheral surface of the first cylindrical portion; A fourth cylindrical portion having a downstream enlarged diameter portion whose tip is fixed to the inner peripheral surface of the finisher, and a downstream exhaust hole formed in the downstream enlarged diameter portion;
A muffler case externally provided on the second cylindrical portion,
A first exhaust passage that is defined by the first cylindrical portion and the second cylindrical portion and communicates with the small exhaust hole; and a first exhaust passage defined between the second cylindrical portion and the silencer case. And a first expansion space defined by the first and third cylindrical portions, the first expansion space being open to the first exhaust passage, and a first expansion space communicating with the first expansion space. A second exhaust passage, a third exhaust passage defined by the third cylindrical portion and the fourth cylindrical portion, and communicating with the second exhaust passage and the downstream exhaust hole; 4. A silencer defined inside the cylindrical portion of No. 4 and comprising a second expansion space which is open to the downstream exhaust hole and communicates with the opening of the finisher. At the downstream end of the exhaust pipe in the exhaust direction, an exhaust pressure adjusting valve for short-circuiting the exhaust pipe and the finisher when the pressure of exhaust gas becomes equal to or higher than a predetermined value is provided. The muffler according to claim 1, wherein the exhaust pipe and the opening of the finisher communicate with each other through the second expansion space by a valve. A shielding bottom that is provided outside the second cylindrical portion and that blocks the second exhaust passage and the first expansion chamber and that connects the first exhaust passage and the second exhaust passage; And a fifth cylindrical portion defining a fourth exhaust passage communicating the first exhaust passage and the first expansion chamber between the second cylindrical portion and the second cylindrical portion. The muffler according to claim 1 or 2, wherein The exhaust pressure regulating valve opens and closes the end of the exhaust pipe, a valve body having a convex shape protruding upstream in the exhaust direction, and a spring pressing the valve body toward the exhaust pipe end. 4. The muffler according to claim 1, further comprising a pressing force adjusting mechanism for adjusting the pressing force of the spring. The pressing force adjusting device includes a holding unit that holds one end of a spring, and a turning unit that adjusts the pressing force by moving the holding unit with respect to the valve body. The muffler according to claim 4, wherein the muffler is located on a line and can be adjusted from an opening of the finisher. The exhaust according to any one of claims 1 to 5, wherein the downstream exhaust holes are formed at predetermined intervals around a periphery of the downstream enlarged diameter portion of the fourth cylindrical portion. Silencer with pressure adjustment valve. The muffler with an exhaust pressure adjusting valve according to any one of claims 1 to 6, wherein the downstream exhaust hole is a square hole whose upstream side is open to the third exhaust passage side. . The muffler according to any one of claims 1 to 6, wherein the downstream exhaust hole is a streamlined hole whose upstream side opens to the third exhaust passage. vessel. A small expansion space is formed upstream of the first exhaust passage and between a downstream closed bottom surface of the first cylindrical portion and an upstream closed side surface of the second cylindrical portion. The muffler with an exhaust pressure adjusting valve according to any one of claims 1 to 8, wherein:

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