JP3813290B2 - Exhaust muffler with built-in valve for automobile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of an automotive exhaust built-in exhaust muffler in which an exhaust pressure sensitive valve that opens and closes according to an exhaust pressure that fluctuates with an increase or decrease in the exhaust flow rate is provided in a tube in a muffler that communicates two chambers.
[0002]
[Prior art]
Conventionally, as an exhaust muffler with a built-in valve for an automobile having an exhaust pressure sensitive valve, for example, the muffler shown in FIG. 6 is known (FIGS. 1 to 3 and JP-A-5-81911 of JP-A-2-81911). No. 202729, Japanese Patent Laid-Open No. 5-98930, etc.).
[0003]
As shown in FIG. 6, when the exhaust pressure sensitive valve is closed, the exhaust muffler has an expansion chamber in the first chamber and a second chamber, a resonator chamber in the third chamber, and the resonator chamber is gradually opened when the valve starts to open. It is configured to move to an expansion room.
[0004]
In addition, the exhaust pressure sensitive valve is provided with a coiled spring that urges the valve shaft in the valve closing direction, and the valve is opened by the force of the exhaust pressure that overcomes the spring urging force.
[0005]
[Problems to be solved by the invention]
However, in the conventional exhaust muffler with built-in valve for a vehicle, since the valve is opened and closed only by the rotation operation around the spring shaft, any valve opening degree from the valve fully closed position to the valve fully opened position is determined. Even if the position is taken, the spring force is constant and has the following problems.
[0006]
(1) Since the spring force is constant at all valve opening positions, for example, when the exhaust pressure increases during acceleration travel, when the exhaust pressure reaches the pressure level that opens the valve, then gradually increase as the exhaust pressure increases. The valve opening / closing response is poor, such as when the valve opens.
[0007]
As a result, when trying to improve engine output at a certain exhaust pressure, the spring force must be set so that the valve starts to open at an exhaust pressure level long before that exhaust pressure is reached. The noise reduction effect in the low exhaust pressure range is sacrificed. On the other hand, if the setting is focused on the muffling effect, the engine output improvement effect is sacrificed.
[0008]
(2) When the exhaust pressure fluctuates at the exhaust pressure level where the valve begins to open after the valve is fully closed, the valve opens and closes repeatedly, causing flapping noise and vibration due to repeated collisions between the valve body and the seating surface. To do.
[0009]
In order to solve these problems, a device that uses an actuator as a motor, detects the engine speed and exhaust pressure, and controls the opening and closing of the valve by driving the actuator when the detected value reaches a set threshold value has been proposed. However (for example, FIGS. 4 and 5 of JP-A-2-81911), the addition of an electronic control system such as an actuator makes the system very expensive.
[0010]
An object of the present invention is to provide an exhaust muffler with a built-in valve for a vehicle that achieves a low-cost, yet silent switching with a highly responsive valve opening / closing operation and prevention of flapping noise and vibration in the valve fully closed region. There is.
[0011]
[Means for Solving the Problems]
(Solution 1)
According to a first aspect of the present invention for solving the above-described problem, an automotive valve in which an exhaust pressure sensitive valve that opens and closes by an exhaust pressure that fluctuates with an increase or decrease in the exhaust flow rate is provided in a tube in a muffler that communicates two chambers. In the built-in exhaust muffler,
The exhaust pressure sensitive valve,
A valve shaft set in a cam-like or elliptical cross-sectional shape in which three of the four directions perpendicular to the rotation center at which the valve body is supported are short in diameter and long in one direction;
The valve fully closed area is a stroke part that allows only a shaft stroke with a width that is slightly wider than the short axis of the shaft, and the valve fully open area that has a width that is slightly wider than the long diameter of the shaft and allows the shaft to rotate to a fully open angle. When,
A valve spring that applies a strong urging force to the valve shaft in the stroke region from the fully closed valve, and a weak urging force to the valve shaft in the rotation region where the valve opens and reaches a fully open angle;
It is set as the valve | bulb provided with.
[0012]
(Solution 2)
The invention according to claim 2 which solves the above-mentioned problem is the exhaust muffler with built-in valve for automobile according to claim 1,
A valve bearing is fixed as a component constituting the exhaust pressure sensitive valve as a unit, a support plate for supporting one end of a valve spring is added, and the support plate is fixed to a base plate on which a valve seat surface is formed. .
[0013]
(Solution 3)
The invention according to claim 3 for solving the above-mentioned problem is the exhaust muffler with built-in valve for automobile according to claim 2,
The base plate is a baffle plate that partitions the inside of the muffler into a plurality of chambers.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
First, the configuration will be described.
[0015]
The first embodiment corresponds to the first, second, and third aspects of the invention.
[0016]
FIG. 1 is a cross-sectional view of a main part showing an exhaust pressure sensitive valve of an exhaust muffler with a built-in valve for an automobile according to a first embodiment, and FIG. 2 is a perspective view of the main part showing an exhaust pressure sensitive valve of an exhaust muffler with a built-in automotive valve of a first embodiment. FIG. 3 is an overall cross-sectional view showing the exhaust muffler with built-in valve for automobile according to the first embodiment.
[0017]
3, A is an exhaust pressure sensitive valve, 10 is a muffler side plate, 11 is a front end plate, 12 is a rear end plate, 13 is a first baffle plate, 14 is a second baffle plate, 15 is an exhaust input tube, and 16 is a first end plate. 1 tube, 17 is a second tube, 18 is a third tube, 19 is an exhaust output tube, 20 is a first chamber, 21 is a second chamber, and 22 is a third chamber.
[0018]
The exhaust pressure sensitive valve A is a valve that opens and closes by an exhaust pressure that fluctuates as the exhaust flow rate increases and decreases, and is provided at the end of the third tube 18 in the muffler that communicates the first chamber 20 and the third chamber 22. It has been.
[0019]
The exhaust input tube 15 is connected to an exhaust tube from the engine, and introduces exhaust gas into the second chamber 21.
[0020]
The first tube 16 is provided on the second baffle plate 14, one end opening in the second chamber 21 and the other end opening in the third chamber 22.
[0021]
The second tube 17 is provided on the first baffle plate 13, and one end opens into the first chamber 20 and the other end opens into the second chamber 21.
[0022]
The third tube 18 is provided on the first baffle plate 13 and the second baffle plate 14, an exhaust pressure sensitive valve A is provided at one end, and the other end is open to the third chamber 22. When the atmospheric pressure sensitive valve A is opened, the first chamber 20 and the third chamber 22 communicate with each other.
[0023]
The exhaust output tube 19 is provided on the first baffle plate 13 and the second baffle plate 14, one end opening to the first chamber 20, and the other end opening to the outside air.
[0024]
When the exhaust pressure sensitive valve A is closed, the first chamber 20 and the second chamber 21 are expansion chambers, and the third chamber 22 is a resonator chamber. When the exhaust pressure sensitive valve A starts to open, the third chamber 22 gradually moves from the resonator chamber to the expansion chamber.
[0025]
1 and 2, A is an exhaust pressure sensitive valve, 1 is a valve body, 2 is a valve opening / closing arm, 3 is a valve shaft, 4 is a valve bearing hole (valve bearing), 5 is a valve spring, 6 is a support plate, 7 is a collision buffer, 13 is a first baffle plate (base plate), and 18 is a third tube.
[0026]
The valve body 1 is dish-shaped and has a valve seat surface 1a with a tapered surface. The valve seat surface 1a is brought into contact with a collision cushioning material 7 provided on the valve seat surface 13a formed on the first baffle plate 13 in the valve closed state, thereby ensuring close sealing performance and metal contact. I try to prevent hitting sound.
[0027]
The valve shaft 3 is a shaft on which the valve main body 1 is supported via the valve opening / closing arm 2, and is a deformed elliptical cross section in which three of the four directions perpendicular to the rotation center O are short in diameter and long in one direction. The shape is set.
[0028]
The valve bearing hole 4 is formed in the support plate 6, the valve fully closed region is a stroke portion 4 a that is slightly wider than the short diameter of the valve shaft 3 and allows only the shaft stroke, and the valve fully open region is the long diameter of the valve shaft 3. This is a bearing hole that is a rotating portion 4b that allows shaft rotation to a fully open angle with a slightly wider width.
[0029]
The valve spring 5 is a plate spring having one end fixed to the support plate 6 and the other end pressed against the upper surface of the valve shaft 3, and applies a strong urging force to the valve shaft 3 in the stroke region from the fully closed valve. In the rotation region where the valve opens and reaches the full opening angle, a weak biasing force is applied to the valve shaft 3.
[0030]
The support plate 6 is added as a component when the exhaust pressure sensitive valve A is configured as a unit. The support plate 6 forms a valve bearing hole 4 and supports one end of the valve spring 5. The support plate 6 is fixed to the first baffle plate 13 on which the valve seat surface 13a is formed. That is, the first baffle plate 13 is also used as a base plate for fixing the support plate 6.
[0031]
Next, the operation will be described.
[0032]
[Valve opening and closing action]
When the valve is fully closed, as shown in FIG. 4 (a), the valve shaft 3 is strongly attached to the valve shaft 3 in the downward direction by the valve spring 5 while the valve shaft 3 is fitted in the stroke portion 4a of the valve bearing hole 4. Since force is given, the valve shaft 3 is closely fitted to the stroke portion 4a.
[0033]
Therefore, even if the exhaust pressure that fluctuates at a low pressure level from the third tube 18 acts on the valve body 1 when the valve is fully closed, the valve body 1 does not fluctuate or vibrate with the fluctuation of the exhaust pressure. .
[0034]
In the region where the valve opens from the fully closed state, as shown in FIG. 4 (b), a strong urging force is applied to the valve shaft 3, so that the valve shaft 3 strokes against this urging force. This is a stroke motion that linearly moves upward in the drawing along the portion 4a.
[0035]
Therefore, in the region where the valve opens from the fully closed state as the exhaust pressure increases, the valve starts to open due to the gentle stroke movement of the valve body 1.
[0036]
In the region where the valve is opened and has a full opening angle, the valve shaft 3 moves from the stroke portion 4a to the rotating portion 4b as shown in FIG. This is a rotational motion with O as the axial position. At this time, the valve spring 5 comes into contact along the minor axis of the valve shaft 3 with little displacement, so that the urging force (proportional to the displacement amount) applied to the valve shaft 3 is weak.
[0037]
Therefore, when the stroke motion ends with the increase of the exhaust pressure, the valve can be opened to the full open at once by a small increase of the exhaust pressure.
[0038]
Further, in the fully open position, the valve shaft 3 is subjected to the rotation restriction by the valve spring 5, and thus the fully open state is maintained.
[0039]
On the other hand, when the force applied to the valve body 1 is reduced due to the exhaust pressure, the operation from the valve fully open to the valve fully closed is closed at a stretch by the rotary motion, and then closes to the valve fully closed by a linear motion. And return.
[0040]
[Valve opening characteristics]
FIG. 5 shows a contrast characteristic between the valve opening characteristic (solid line) of the present invention and the conventional valve opening characteristic (dotted line) representing the change of the valve opening degree with respect to the change of the exhaust pressure.
[0041]
In the case of the present invention, the valve closing is first maintained until the exhaust pressure rises to P1, and when the exhaust pressure reaches P1, the slow motion starts, and when the exhaust pressure reaches P2, the stroke motion ends and the rotational motion starts. . Then, the exhaust pressure is slightly increased from P2 to P3, and the valve is fully opened. That is, the valve opening response time from the valve fully closed to the fully opened is T1.
[0042]
On the other hand, in the conventional case in which a coiled spring is provided on the valve shaft, the valve starts to open when the exhaust pressure reaches P0 (<P1), and then gradually increases as the exhaust pressure increases. When the opening degree increases and the exhaust pressure reaches P4 (> P3), the valve is fully opened. That is, the valve opening response time from the valve fully closed to the fully opened is T2 (> T1).
[0043]
That is, according to the present invention, the valve opening response time can be greatly shortened as compared with the conventional valve, and a highly responsive valve opening / closing operation can be obtained.
[0044]
As a result, it is possible to perform an optimum setting that achieves both a silencing effect in the low exhaust pressure range and an engine output improvement effect in the high exhaust pressure range by switching the silencing mode on and off by a highly responsive valve opening / closing operation.
[0045]
Next, the effect will be described.
[0046]
(1) A valve in which the exhaust pressure sensitive valve A is set to have a deformed elliptical cross-sectional shape in which three of the four directions perpendicular to the rotation center O on which the valve body 1 is supported are short in diameter and long in one direction. The shaft 3 and the valve fully closed region have a stroke portion 4a that allows only a shaft stroke with a width slightly wider than the short axis of the valve shaft 3, and the valve fully open region has a shaft rotation with a width slightly wider than the long diameter of the valve shaft 3. In the stroke region from the valve fully closed, a strong biasing force is applied to the valve shaft 3 in the stroke region from the valve fully closed, and the valve shaft 3 is weakly applied in the rotation region where the valve is opened to the full open angle. The valve spring 5 is designed to provide power, so that it is low-cost compared to the electronic control system, but the mute mode switching by the highly responsive valve opening / closing operation and the entire valve It is possible to provide a motor vehicle built-in valve exhaust muffler to achieve prevention of fluttering sound or vibration at frequency.
[0047]
(2) A valve bearing hole 4 is formed as a component constituting a unit of the exhaust pressure sensitive valve A and a support plate 6 for supporting one end of the valve spring 5 is added, and the support plate 6 is formed with a valve seat surface 13a. Since the first baffle plate 13 is fixed, the valve unit can be widely shared regardless of the tube diameter of the third tube 18 that is sensitively changed in the silencing characteristic tuning when the vehicle type or the applied engine model is changed.
[0048]
(3) Since the base plate for fixing the support plate 6 is the first baffle plate 13 that partitions the inside of the muffler into the first chamber 20 and the second chamber 21, the base plate for fixing the support plate 6 is provided separately. Compared to the case, an increase in the weight of the exhaust muffler can be suppressed.
[0049]
(Other embodiments)
In the first embodiment, the valve shaft has a deformed elliptical cross-sectional shape. However, the valve shaft may have a cam shape corresponding to the bearing.
[0050]
In the first embodiment, an example of a valve bearing hole formed in the support plate as the valve bearing is shown, but it may be a valve bearing groove or the like, and is formed separately from the support plate and fixed to the support plate. It may be an example to do.
[0051]
In the first embodiment, a leaf spring is used as an example of the valve spring. However, a strong biasing force is applied to the valve shaft in the stroke region from the fully closed valve, and the valve shaft is applied to the valve shaft in the rotational region where the valve opens and has a fully opened angle. The spring is not limited to a leaf spring as long as it provides a weak biasing force.
[0052]
【The invention's effect】
According to the first aspect of the present invention, the exhaust valve built-in exhaust for automobiles is provided with an exhaust pressure sensitive valve that opens and closes by an exhaust pressure that fluctuates with an increase or decrease in the exhaust flow rate, provided in a tube in a muffler that communicates two chambers In the muffler, the exhaust pressure sensitive valve is a valve shaft having a cam-shaped or elliptical cross-sectional shape in which three of the four directions perpendicular to the rotation center at which the valve body is supported are short in diameter and one is long. The valve fully closed region is a stroke part that allows only a shaft stroke with a width slightly wider than the short axis of the shaft, and the valve fully open region is a rotating part that allows a shaft rotation to a fully open angle with a width slightly wider than the long axis of the shaft. A valve bearing and a valve that applies a strong urging force to the valve shaft in the stroke region from the fully closed valve, and a weak urging force to the valve shaft in the rotating region where the valve opens to a fully open angle. A valve equipped with a spring provides an exhaust muffler with a built-in valve for automobiles that achieves low-cost, but is able to switch the mute mode with a highly responsive valve opening and closing operation and prevent the generation of flapping noise and vibration in the valve fully closed area Can be
[0053]
According to a second aspect of the present invention, in the exhaust muffler with a built-in valve for an automobile according to the first aspect, a support for fixing a valve bearing and supporting one end of a valve spring as a component constituting the exhaust pressure sensitive valve as a unit. Since the plate is added and the support plate is fixed to the base plate on which the valve seat surface is formed, in addition to the effect of the invention of claim 1, when the vehicle type or the applied engine model is changed, the tube is sensitively changed in the silencing characteristic tuning The valve unit can be widely shared regardless of the diameter.
[0054]
In the invention according to claim 3, in the exhaust muffler with built-in valve for automobile according to claim 2, since the base plate is a baffle plate that partitions the inside of the muffler into a plurality of chambers, in addition to the effect of the invention according to claim 2 As compared with the case where the base plate for fixing the support plate is provided separately, an increase in the weight of the exhaust muffler can be suppressed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part showing an exhaust pressure sensitive valve of an exhaust muffler with a built-in valve for an automobile according to Embodiment 1;
FIG. 2 is a perspective view of a main part showing an exhaust pressure sensitive valve of the exhaust muffler with a built-in valve for an automobile according to the first embodiment.
FIG. 3 is an overall cross-sectional view showing an exhaust muffler with a built-in valve for an automobile according to Embodiment 1;
4 is a valve opening / closing action explanatory view of an exhaust pressure sensitive valve according to Embodiment 1. FIG.
FIG. 5 is a diagram showing a contrast characteristic between a valve opening characteristic (solid line) of the present invention and a conventional valve opening characteristic (dotted line), which represents a change in valve opening degree with respect to a change in exhaust pressure.
FIG. 6 is an overall sectional view showing a conventional exhaust muffler with a built-in valve for an automobile.
[Explanation of symbols]
A Exhaust pressure sensitive valve 1 Valve body 2 Valve open / close arm 3 Valve shaft 4 Valve bearing hole (valve bearing)
5 Valve spring 6 Support plate 7 Collision buffer 13 First baffle plate (base plate)
18 Third tube

Claims (3)

In an exhaust muffler with a built-in valve for an automobile, an exhaust pressure sensitive valve (A) that opens and closes by an exhaust pressure that fluctuates with an increase or decrease in the exhaust flow rate is provided in a tube (18) in a muffler that communicates two chambers.
The exhaust pressure sensitive valve (A),
A valve shaft (3) set in a cam-like or elliptical cross-sectional shape in which three of the four directions perpendicular to the rotation center at which the valve body (1) is supported are short in diameter and long in one direction;
The valve fully closed area is a stroke part (4a) that allows only a shaft stroke with a width slightly wider than the short axis of the shaft, and the valve fully open area is a rotating part that allows a shaft rotation to a fully open angle with a width slightly wider than the long diameter of the shaft ( 4b) a valve bearing (4),
A valve spring (5) that applies a strong urging force to the valve shaft (3) in the stroke region from the fully closed valve, and a weak urging force to the valve shaft (3) in the rotation region where the valve opens and has a full opening angle;
An exhaust muffler with a built-in valve for automobiles, characterized in that the valve has a valve. The exhaust muffler with a built-in valve for automobiles according to claim 1,
As a component constituting the exhaust pressure sensitive valve (A) as a unit, a valve bearing (4) is fixed and a support plate (6) supporting one end of a valve spring (5) is added, and the support plate (6) is connected to the valve. An exhaust muffler with a built-in valve for automobiles, wherein the exhaust muffler is fixed to a base plate on which a seat surface is formed. The exhaust muffler with built-in valve for automobiles according to claim 2,
An exhaust muffler with a built-in valve for an automobile, wherein the base plate is a baffle plate (13) dividing the inside of the muffler (A) into a plurality of chambers (20), (21).

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