JP2009215942A - Muffler for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a muffler for a vehicle can achieve the requirements for a reduction in the noise and the back pressure of the exhaust at a high level by flexibly changing the flow pattern of the exhaust using an electronic control valve. <P>SOLUTION: This muffler for a vehicle includes an inlet pipe 4 branched from a main pipe 3 on the upstream side of the exhaust and introducing the exhaust gas into a muffler body 2; a through pipe 5 branched from the main pipe 3, extending through the muffler body 2, and having small holes 5a for exhausting the exhaust gas in the muffler body 2 at the intermediate part; a valve V1 installed in the through pipe 5 on the outside of the muffler body 2; and an ECU 18 for controllably opening and closing the valve V1 according to the operating conditions of an engine. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a muffler for a vehicle.

2. Description of the Related Art Conventionally, a technique for providing a pressure-exhaust-sensitive control valve or an electronic control valve in a silencer body is known (see Patent Documents 1 and 2).
JP 2006-291719 A JP-A-2005-139918

However, since the conventional exhaust pressure sensitive control valve opens and closes according to the exhaust pressure, there is a problem that it cannot be opened and closed at an arbitrary timing like the electronic control valve.
On the other hand, when the electronic control valve is provided in the silencer body, it is difficult to secure an installation space, and the sealing performance and assembly / maintenance performance of each part are also deteriorated.

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to make it possible to variously change the flow mode of exhaust using an electronic control valve, and to reduce the noise and back pressure of the exhaust. It is providing the silencer for vehicles which can achieve the demand of this at a high level.

  In the first aspect of the present invention, the inlet pipe is branched from the main pipe on the exhaust upstream side and introduces exhaust gas into the silencer main body. A through pipe having a discharge portion for discharging exhaust gas in the silencer body, an electronic control valve provided outside the silencer body on the exhaust upstream side of the through pipe, and an electronic control valve according to the operating state of the engine It is characterized by comprising control means for performing opening / closing control.

According to the first aspect of the present invention, the control means controls the opening and closing of the electronic control valve in accordance with the operating state of the engine.
Thus, when the electronic control valve is closed, exhaust flows from the inlet pipe into the through pipe through the silencer body, and then a flow path is formed. On the other hand, when the electronic control valve is opened, the exhaust passes through the through pipe. In this way, a flow path for directly discharging is formed, whereby at least two or more exhaust gas flow modes can be formed.
Therefore, the flow mode of the exhaust gas can be changed in various ways using the electronic control valve, and the demand for low exhaust gas noise and low back pressure can be achieved at a high level.
In addition, since the electronic control valve is provided at the position outside the silencer body in the through pipe, it is not necessary to secure a space for installing the electronic control valve in the silencer body, ensuring easy sealing, assembly, maintenance, etc. It is easy to adopt in practice.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1 will be described below.
FIG. 1 is a plan view showing a muffler for a vehicle according to the first embodiment, FIG. 2 is a diagram for explaining the inside of the muffler for a vehicle according to the first embodiment, and FIG. 3 is a flowchart for explaining the opening / closing control of the valve according to the first embodiment. 4-7 is a figure explaining the effect | action of the silencer for vehicles of Example 1. FIG.

First, the overall configuration will be described.
As shown in FIGS. 1 and 2, the vehicle silencer 1 according to the first embodiment includes a silencer body 2, a main pipe 3, an inlet pipe 4, a through pipe 5, and the like.

The silencer main body 2 is sealed inside by a cylindrical shell 6 and substantially vessel-shaped end plates 7 and 8 that close both open ends of the shell 6.
The shell 6 is formed in a cylindrical shape by winding a flat base material in multiple layers, and is fixed by a plurality of spot welds X1 in which a winding direction start end portion and a termination end portion are provided along the axial direction. ing.
Further, the open end portions of the corresponding end plates 7 and 8 are overlapped inside the open end portion of the shell 6, and both of them are fixed by welding (not shown) over the entire circumference.

The interior of the silencer body 2 is divided by three plate-like baffle plates 9, 10, thereby forming three chambers R 1 to R 3 in the silencer body 2.
The outer peripheral parts of the baffle plates 9 and 10 are fixed to the shell 6 by spot welding (not shown).

  A flange 3 a connected to a connection pipe on the engine side (not shown) is fixed to the exhaust upstream end of the main pipe 3, while the exhaust downstream side is branched into an inlet pipe 4 and a through pipe 5.

The inlet pipe 4 is bent in a state of branching in the direction perpendicular to the axis of the main pipe 3, and is further disposed in a state of passing through the end plate 7 and the baffle plates 9, 10, and the exhaust downstream side end thereof is a chamber R3. It is communicated to.
A plurality of small holes 4a communicating with the chamber R1 and a plurality of small holes 4b communicating with the chamber R2 are formed in the middle portion of the inlet pipe 4.
The total opening area of the small holes 4a is smaller than that of the small holes 4b, and the total opening area of the small holes 4b is set to be larger than the opening end of the inlet pipe 4.

  The through pipe 5 is bent in a substantially L shape along the axial direction of the main pipe 3, and is further disposed in a state of passing through the end plates 7 and 8 and the baffle plates 9 and 10, and the exhaust downstream side end thereof The part communicates with the outside.

A butterfly valve V1 is built in the through pipe 5 at a position outside the silencer body 2 as an electronic control valve.
The valve V1 is provided so that it can be opened and closed by rotating a rotary shaft 12 fixed to a disc-like valve body 11 around the axis, and the rotary shaft is driven to rotate by an actuator 13 that simplifies the illustration. ing.
Further, a plurality of small holes 5a (corresponding to the discharge portion in the claims) formed in the middle portion of the through pipe 5 are formed in communication with the chamber R1.

Further, a communication pipe 14 and a communication pipe 15 are disposed through the baffle plates 9 and 10.
Both ends of the communication pipe 14 communicate with the chambers R1 and R3, and a plurality of small holes 14a communicated with the chamber R2 are formed in the middle.
The total opening area of the small holes 14 is set to be larger than the opening end portion of the communication pipe 14.
The communicating pipe 15 has both open ends communicating with the chambers R1 and R3, and an end facing the chamber R1 is provided with a valve V2 as an exhaust pressure sensitive control valve.
The valve V2 is composed of a disc-like valve body 17 that is urged in a direction to close the open end of the communication pipe 15 by the urging force of the spring 16, and the exhaust pressure in the communication pipe 15 becomes a predetermined value or more. When this occurs, the valve body 17 opens against the urging force so that the chambers R1 and R3 are in communication.
In addition, the penetration part of the end plates 7 and 8 and the baffle plate in each of the pipes 4, 5, 14, and 15 is fixed by welding (not shown) over the entire circumference.

The drive control of the actuator 13, that is, the opening / closing control of the valve V1, is performed by an ECU 18 (Engine Control Unit, corresponding to the control means in the claims) that detects and controls the operating state of the engine from the detection results of the various sensors 19. It has become.
In addition, all the structural members of the vehicle silencer of the first embodiment are made of metal.

Next, an example of opening / closing control of the valves V1, V2 by the ECU 18 will be described based on the flowchart of FIG.
In the first embodiment, the ECU 18 performs opening / closing control of the valve V <b> 1 using the detection result of an existing engine speed sensor that is one of the various sensors 19.
Note that an existing accelerator opening sensor, intake air amount sensor, or the like may be used instead of the rotational speed sensor, or a sensor for detecting the operating state of the engine may be newly provided.
The control described below is processing that is repeatedly performed by the ECU 18 at predetermined time intervals from the start to the end of the engine.

  First, in step S1, the engine speed N is detected.

Next, in step S2, it is determined whether or not the engine speed N detected in step S1 is a preset low speed range (for example, 1000 rpm ≦ N), and if it is a low speed range, the process proceeds to step S3. If not in the low rotation range, the process proceeds to step S4.
In step S4, it is determined whether or not the engine speed N detected in step S1 is a preset intermediate rotation range (for example, 1000 rpm <N ≦ 5000 rpm). If the rotation speed is in the intermediate rotation range, the process proceeds to step S5. If it is not in the middle rotation range, the process proceeds to step S6.
In step S6, it is determined whether or not the engine speed N detected in step S1 is a preset high engine speed range 1 (for example, 5000 rpm <N <6000 rpm). If the engine speed is high, the process proceeds to step S7. On the other hand, if it is not the high rotation region 1, the process proceeds to step S8.
In step S8, it is determined whether or not the engine speed N detected in step S1 is a preset high engine speed range 2 (eg, 6000 rpm <N). If the engine speed is high, the process proceeds to step S9. If it is not the rotation range 2, the process is terminated.
In the first embodiment, if it is determined in step S8 that it is not in the high rotation range 2, the process is terminated, and the process is performed again after a predetermined time when the process is repeated, but the predetermined time has elapsed. You may make it return to step S1 before.

In step S3, the valve V1 is closed and the process is terminated.
In step S5, the valve V1 is closed and the process is terminated.
In step S7, the valve V1 is opened and the process is terminated.
In step S9, the valve V1 is opened and the process is terminated.

Next, the operation will be described.
<About muffling action>
In the vehicle silencer 1 configured as described above, the ECU 18 detects the engine speed N when the engine starts (step S1).

<At low engine speed>
When the engine speed N is a preset low speed range, the valve V1 is closed as shown in FIG. 4 (step S2 → step S3).

As a result, the entire amount of exhaust gas (shown by broken line arrows) discharged from the engine flows into the chamber R2 through the small hole 4b of the inlet pipe 4.
At this time, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R2, and the chamber R2 functions as an expansion chamber.
Further, when the engine is running at a low speed, the exhaust pressure of the communication pipe 15 communicating with the inlet pipe 4 and the chamber R3 does not reach the valve opening pressure of the valve V2, so that the valve V2 is closed, whereby the inlet pipe 4 The noise energy of the exhaust gas enters the room R3 (specifically including the communication pipe 15 in detail) and can be silenced by resonance, and the room R3 functions as a resonator room.
Next, the exhaust gas flowing into the chamber R2 flows into the small hole 14a of the communication pipe 14, and then flows into the chamber R1.
At this time, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R1, and the chamber R1 functions as an expansion chamber.
Next, the exhaust gas flowing into the chamber R1 flows into the small hole 5a of the through pipe 5 and is then discharged out of the silencer body 2.

  Accordingly, the chambers R1 and R2 can function as an expansion chamber and the chamber R3 can function as a resonator chamber, so that the noise reduction required at the time of low engine rotation can be realized.

<During engine rotation>
When the engine speed N is in the middle speed range, as shown in FIG. 5, the valve V1 is closed (step S4 → step S5).

  As a result, the entire amount of exhaust gas (shown by broken line arrows) discharged from the engine flows into the inlet pipe 4.

Further, the communication pipe 15 communicated with the inlet pipe 4 and the chamber R3 reaches the opening pressure of the valve V2 to open the valve V2, and a part of the exhaust of the inlet pipe 4 flows into the chamber R3, and then the communication pipe 15 Through the chamber R1.
At this time, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R3, and the chamber R4 functions as an expansion chamber.
Similarly, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R1, and the chamber R1 functions as an expansion chamber.
Next, the exhaust gas flowing into the chamber R1 flows into the small hole 5a of the through pipe 5 and is then discharged out of the silencer body 2.

On the other hand, a part of the exhaust from the inlet pipe 4 or a part of the exhaust from the chamber R3 flows into the chamber R2 through the small hole 4b.
At this time, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R2, and the chamber R2 functions as an expansion chamber.
Next, the exhaust gas flowing into the chamber R2 flows into the small hole 14a of the communication pipe 14, and then flows into the chamber R1.
At this time, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R1, and the chamber R1 functions as an expansion chamber.
Next, the exhaust gas flowing into the chamber R1 flows into the small hole 5a of the through pipe 5 and is then discharged out of the silencer body 2.

  Therefore, the chambers R1 to R3 can function as expansion chambers, and the noise reduction required during the middle rotation of the engine can be realized.

<At high engine speed>
When the engine speed N is in the high engine speed range 1, the valve V1 is opened as shown in FIG. 6 (step S6 → step S7).

As a result, the exhaust discharged from the engine (illustrated by a broken arrow) branches from the main pipe 3 to the inlet pipe 4 and the through pipe 5.
Further, since the pressure of the communication pipe 15 communicated with the inlet pipe 4 and the chamber R2 does not reach the valve opening pressure of the valve V2, the valve V2 is closed.
Therefore, the noise energy of the exhaust gas can be made to enter the chambers R2 and R3 through the small holes 4b and the opening ends of the inlet pipe 4, respectively, and can be silenced by the resonance action, and the chambers R2 and R3 function as a resonator chamber.
The exhaust from the inlet pipe 4 flows into the chamber R1 through the small hole 4a.
At this time, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R1, and the chamber R1 functions as an expansion chamber.
Next, the exhaust gas flowing into the chamber R1 flows into the small hole 5a of the through pipe 5 and is then discharged out of the silencer body 2.

  On the other hand, the exhaust gas flowing into the through pipe 5 merges with the exhaust gas in the chamber R1 flowing in from the small hole 5a and is discharged out of the silencer body 2.

Therefore, the chamber R1 can function as an expansion chamber, and the chambers R2 and R3 can function as a resonator chamber, so that noise reduction at high engine speed can be realized.
Further, since the through pipe 5 has the same diameter as the main pipe 3 and has a shape along the exhaust flow direction of the main pipe 3, a large amount of exhaust gas is introduced into the through pipe 5 to the outside of the silencer body 2. It can be discharged and the low back pressure required at high engine speeds can be achieved.

<At high engine speed>
When the engine speed N is in the high engine speed range 2, as shown in FIG. 7, the valve V1 is opened (step S8 → step S9).

As a result, the exhaust discharged from the engine (illustrated by broken line arrows) branches into the inlet pipe 4 and the through pipe 5.
Further, the pressure of the communication pipe 15 communicated with the inlet pipe 4 and the chamber R2 reaches the valve opening pressure of the valve V2, the valve V2 opens, and a part of the exhaust of the inlet pipe 4 flows into the chamber R3 and then communicates with it. It flows into the chamber R1 through the pipe 15.
At this time, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R3 from the inlet pipe 4, and the chamber R3 functions as an expansion chamber.
Similarly, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R1 from the communication pipe 15, and the chamber R1 functions as an expansion chamber.

On the other hand, a part of the exhaust from the inlet pipe 4 flows into the chamber R2 from the small hole 4b and then flows into the small hole 14a of the communication pipe 14.
At this time, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R2, and the chamber R2 functions as an expansion chamber.
Next, it flows into the chamber R <b> 1 from the communication pipe 14 and further flows into the small hole 5 a of the through pipe 5, and is then discharged out of the silencer body 2.
At this time, the sound can be silenced by the expansion / contraction action of the exhaust gas flowing into the chamber R1, and the chamber R1 functions as an expansion chamber.

  On the other hand, the exhaust gas flowing into the through pipe 5 merges with the exhaust gas in the chamber R1 flowing in from the small hole 5a and is discharged out of the silencer body 2.

Therefore, the chambers R1 to R3 can function as expansion chambers, and a reduction in noise during high engine rotation can be realized.
Further, since the through pipe 5 has the same diameter as the main pipe 3 and has a shape along the exhaust flow direction of the main pipe 3, a large amount of exhaust gas is introduced into the through pipe 5 to the outside of the silencer body 2. It can be discharged and the low back pressure required at high engine speeds can be achieved.

Thus, in the first embodiment, four exhaust flow modes can be formed according to the engine speed, that is, the engine operating state, depending on the open / closed state of the valves V1 and V2.
In addition, it is required in the case of high rotational speed and low noise required when the engine speed is in the low rotational range, low noise and low back pressure required in the middle rotational range. The low back pressure can be realized, and the demand for low exhaust noise and low back pressure can be achieved at a high level.

<Changes in room functions>
Further, the chambers R2 and R3 can be made to function as an expansion chamber and a resonator chamber depending on the open / closed state of the valves V1 and V2, and the characteristics (capacity) of the expansion chamber and the resonator chamber can be changed without providing a new chamber. Can be changed.

<Valve installation position>
Moreover, since the valve V1 is provided at a position outside the silencer body 2 of the through pipe 5, it is easier to ensure installation space and sealability, assembling and maintenance than in the case where the valve V1 is provided in the silencer body 2. Easy to adopt in practice.

Next, the effect will be described.
As described above, in the invention of the first embodiment, the main pipe 3 is branched from the exhaust upstream side, and is branched from the inlet pipe 4 for introducing the exhaust into the silencer body 2 and the main pipe 3 on the exhaust upstream side. The through pipe 5 is provided in the middle of the silencer body 2 and has a small hole 5a for exhausting the exhaust gas in the silencer body 2 in the middle, and the silencer body 2 outside the exhaust pipe upstream of the through pipe 5 And the ECU 18 that controls the opening and closing of the valve V1 in accordance with the operating state of the engine. Therefore, it is possible to variously change the flow mode of the exhaust using the electronic control valve, and to reduce the noise and the height of the exhaust. The demand for pressure can be achieved at a high level.

  Further, since the valve V1 is provided in the through pipe 5 at a position outside the silencer body 2, it is not necessary to secure a valve installation space in the silencer body 2, and ensuring sealing performance, assembling and maintenance are easy. It is easy to adopt in practice.

  Moreover, since the valve V2 capable of changing the flow mode of the exhaust gas is disposed in the silencer body 2, an exhaust flow mode can be further formed.

Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and design changes and the like within the scope not departing from the gist of the present invention are included in the present invention.
For example, the specific structure within the silencer body can be set as appropriate.
Further, the valve V1 can be opened and closed in a multistage or continuous manner.

It is a top view which shows the silencer for vehicles of Example 1. It is a figure explaining the inside of the silencer for vehicles of Example 1. It is a flowchart explaining the opening / closing control of the valve | bulb of Example 1. FIG. It is a figure explaining the effect | action of the vehicle silencer of Example 1. FIG. It is a figure explaining the effect | action of the vehicle silencer of Example 1. FIG. It is a figure explaining the effect | action of the vehicle silencer of Example 1. FIG. It is a figure explaining the effect | action of the vehicle silencer of Example 1. FIG.

Explanation of symbols

R1, R2, R3 Chamber V1 valve (electronic control valve)
V2 valve (exhaust pressure sensitive control valve)
X1 spot welding 1 vehicle silencer 2 silencer body 3 main pipe 3a flange 4 inlet pipe 4a, 4b small hole 5 through pipe 5a small hole 6 shell 7, 8 end plate 9, 10 baffle plate 11 valve body 12 rotating shaft 13 Actuator 14, 15 Communication pipe 14a Small hole 16 Spring 17 Valve element 18 ECU
19 Various sensors (rotational speed sensor)

Claims (2)

An inlet pipe branched from the main pipe upstream of the exhaust and introducing exhaust into the silencer body;
A through pipe branched from the main pipe and disposed through the silencer body, and having a discharge part for discharging exhaust gas in the silencer body in the middle part;
An electronic control valve provided outside the silencer body on the exhaust upstream side of the through pipe;
A vehicle silencer comprising control means for performing opening / closing control of an electronic control valve in accordance with an operating state of an engine. The muffler for a vehicle according to claim 1,
A silencer for a vehicle, characterized in that an exhaust pressure sensitive control valve capable of changing a flow mode of exhaust gas in the silencer body is disposed in the silencer body.

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