JPH08232635A - Control-type exhaust system - Google Patents

Abstract

PURPOSE: To contrive valve control in the low rotational range of an engine while providing an advantage in cost and space as well as to obtain smooth acceleration feeling and comfortable acceleration exhaust sound in the acceleration operation while achieving reduction of cost, miniaturization, and common use in a control-type exhaust system in which a valve member for controlling exhaust pressure and exhaust sound is provided on the exhaust system. CONSTITUTION: A control-type exhaust system is provided with a pressure conduit pipe (b) one end of which is opened in an exhaust tube (a) upstream of muffler of an exhaust system, a cylinder type actuator (e) with a cylinder chamber (c) to which the other end of the pressure conduit pipe (b) is connected, a fluctuation pressure regulating member (f) provided on the pressure conduit tube (b) for regulating the pressure fluctuation by narrowing the sectional area of a passage for exhaust gas flow to be introduced from the exhaust tube (a), and a control valve (h) connected to a piston rod (g) of the cylinder type actuator (e) and the valve opening of which is continuously changed according to the side of the piston stroke.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control type exhaust system system in which an exhaust system from an engine to a tail tube is provided with a valve member for controlling exhaust pressure and exhaust sound.

[0002]

2. Description of the Related Art Conventionally, as actuators for controlling opening / closing of valve members provided in an exhaust system, for example, the actuators listed below are known.

(1) Motor Actuator There is known an actuator that controls the opening / closing of a servomotor by rotating the servomotor to a valve shaft by means of a wire (Japanese Patent Laid-Open No. 3-185209, etc.).

(2) Diaphragm type positive pressure actuator An actuator is known in which the internal pressure of a muffler is introduced into a diaphragm chamber and a valve provided inside the muffler is opened / closed by the balance between the magnitude of exhaust pressure and the spring force. 4-
No. 124418).

(3) Diaphragm Negative Pressure Actuator There is known an actuator that guides engine intake pressure to a diaphragm chamber via a tank and a solenoid valve to open and close a valve provided upstream of a muffler (Japanese Patent Laid-Open No. 2-2).
59217).

[0006]

However, the actuators used in the conventional control type exhaust system system have the following problems.

(1) The motor actuator requires an electronic controller that outputs a control command in accordance with the engine speed and the like, and the servo motor itself is expensive, resulting in a high system cost. Further, also in the diaphragm type actuator, if a solenoid valve that is electronically controlled from the outside is provided, the cost similarly increases.

(2) In the diaphragm type positive pressure actuator and the diaphragm type negative pressure actuator, since it is necessary to secure a sufficient pressure receiving area, the actuator diameter becomes large, the system becomes large, and the layout is increased. It is difficult to use it for various vehicle models with different installation space.

Further, in the diaphragm type negative pressure actuator disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2-259217, since the negative pressure is taken out from the engine intake pressure, the muffler provided at the rear of the vehicle has To guide
It has the drawback of requiring long piping.

(3) Both the motor actuator and the diaphragm type actuator are turned on / off by fully opening or closing the valve, and, for example, exhaust static pressure and exhaust in the engine rotation region where the valve is switched from closed to open during acceleration operation. The sound exhibits a characteristic of temporarily lowering, a smooth acceleration feeling cannot be obtained, and an unnatural acceleration exhaust sound is produced.

The present invention has been made in view of the above problems, and a first object thereof is to provide a control type exhaust system system in which a valve member for controlling exhaust pressure and exhaust sound is provided in an exhaust system. While achieving cost reduction, downsizing, and common use, smooth acceleration feeling and comfortable acceleration exhaust noise are obtained during acceleration operation, and valve control in the low engine speed range is possible while achieving cost and space advantages. Especially.

A second object is to achieve the first object while increasing the dynamic pressure introducing efficiency.

[0013]

In order to achieve the above-mentioned first object, according to the invention described in claim 1, as shown in the claim correspondence diagram of FIG. 1, the exhaust pressure and the exhaust gas are supplied to the exhaust system from the engine to the tail tube. In a control type exhaust system system provided with a valve member for controlling sound, a pressure conduit b having one end opened to an exhaust tube a on an upstream side of a muffler of the exhaust system and guiding a positive pressure according to exhaust pressure; The other end of b is connected to the cylinder chamber c, a cylinder type actuator e having a piston d that strokes according to the pressure level of the cylinder chamber c, and the pressure conduit b is provided in the middle and introduced from the exhaust tube a. A fluctuating pressure regulating member f for regulating pressure variation by narrowing the flow passage cross-sectional area of the exhaust gas flow and a piston rod g of the cylinder type actuator e are connected to each other, Wherein the valve opening is provided with a control valve h is changed steplessly in accordance with the magnitude of the stroke.

In order to achieve the above second object, in the invention according to claim 2, as shown in the claim correspondence diagram of FIG. 1, in the control type exhaust system system according to claim 1, the exhaust tube of the pressure conduit b. The side opening is provided with a dynamic pressure guide member i facing the exhaust gas flow of the exhaust tube a and taking in the exhaust dynamic pressure.

[0015]

The operation of the first aspect of the present invention will be described.

During traveling, a positive pressure corresponding to the exhaust pressure is introduced from the exhaust tube a of the exhaust system by the exhaust gas from the engine into the cylinder chamber c of the cylinder type actuator e through the pressure conduit c. Then, since the piston d strokes in the cylinder chamber c in accordance with this pressure level, the control valve h connected to the piston rod g of the cylinder type actuator e has a valve opening degree in accordance with the magnitude of this piston stroke. It is changed steplessly.

Therefore, for example, when the pressure level of the exhaust pressure rises as the engine speed increases during acceleration operation, the control valve h changes steplessly from the valve closed to the valve open and the valve open. Therefore, there is no temporary decrease in exhaust static pressure and exhaust noise as in the case of switching from valve closed to valve open at a predetermined engine speed, and the exhaust static pressure characteristic and exhaust noise characteristic increase linearly. The characteristics are shown.

As a result, a smooth feeling of acceleration and a comfortable acceleration exhaust sound can be obtained during the acceleration operation performed in the engine rotation region where the valve is closed and the valve is opened.

When the control type exhaust system is applied to a vehicle, an actuator driven by exhaust pressure is used as an actuator for controlling opening / closing of a valve member provided in the exhaust system. Therefore, a motor actuator or a solenoid is used. The cost of the system can be significantly reduced as compared with the system that is electronically controlled by using.

In addition, since the cylinder type actuator e whose outer diameter is smaller than that of the diaphragm type actuator is used as the actuator, the system can be downsized, and with this downsizing, various layouts and installation spaces are required. The system can be shared among various vehicle types.

When the exhaust pressure is introduced through the pressure conduit b,
The exhaust gas flows through the exhaust tube while the gas pressure fluctuates in a cycle according to the number of engine cylinders and the number of revolutions. Therefore, when it is guided to the cylinder chamber c of the cylinder type actuator e as it is, the piston stroke fluctuates due to the pulsating pressure, and the opening / closing operation of the control valve h fluctuates.

On the other hand, since the fluctuating pressure regulating member f is provided in the middle of the pressure conduit b, the flow passage cross-sectional area of the exhaust gas flow accompanied by the pulsation introduced from the exhaust tube a is narrowed and the amplitude of the pulsation is reduced. Is smoothed. That is, since the fluctuating pressure regulating member f exerts a pressure regulating action, fluctuations in the opening / closing operation of the control valve h are suppressed, and this pressure regulating action allows valve control particularly in a low engine speed region where pulsation is severe. It will be possible.

A means using a surge tank for converting dynamic pressure into static pressure is conceivable as means for suppressing this pressure fluctuation, but when this surge tank is adopted, it is disadvantageous in terms of space and cost.

The operation of the second aspect of the present invention will be described.

When the exhaust pressure is guided by the pressure conduit c, a dynamic pressure guide member i for taking in the exhaust dynamic pressure is provided at the opening on the exhaust tube side so as to face the exhaust gas flow of the exhaust tube a. The efficiency of introducing the dynamic pressure of exhaust gas is increased as compared with the configuration in which the pressure conduit c is simply branched from the.

Therefore, the pressure for driving the cylinder type actuator e is (exhaust gas static pressure + exhaust gas dynamic pressure), and the pressure level is higher than in the case where only the exhaust gas static pressure is used as the driving pressure. Even if the die actuator e is used, the piston stroke drive is reliable and stable.

[0027]

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

First, the structure will be described.

FIG. 2 is a view showing a control type exhaust system system according to the embodiment of the present invention, FIG. 3 is an enlarged view of a main part of the control type exhaust system system according to the embodiment of the present invention, and FIG. 4 is a cylinder type actuator according to the embodiment of the present invention. FIG. 5 is a partial cross-sectional view of the variable pressure regulating member shown in FIG.

2 and 3, 1 is an exhaust muffler, 4 is a muffle linelet tube (corresponding to the exhaust tube a), 5 is a first muffler outlet tube, 6 is a second muffler outlet tube, 10 is a pressure conduit, 11
Is a cylinder type actuator, 12 is a control valve, 13
Is a dynamic pressure guide member, 14 is an actuator mounting bracket, 15 is a valve shaft, 16 is a valve opening / closing lever,
Reference numeral 17 is a fluctuating pressure regulating member. The exhaust muffler 1 is
A mufflerlet tube 4 which has a front end plate 1a and a rear end plate 1b, into which exhaust gas from an engine (not shown) enters the front end plate 1a, and a first muffler which exhausts exhaust gas through the inside of the muffler. The outlet tube 5 is connected to the rear end plate 1b, and the rear end plate 1b is provided with a control valve 12, and a second muffler outlet tube 6 is connected to control the opening / closing of the control valve 12 to adjust the exhaust gas discharge.

One end of the pressure conduit 10 is opened in the muffle linelet tube 4, and a tapered dynamic pressure is provided at the open end so as to face exhaust gas flow from the muffle line tube 4 and take in exhaust gas dynamic pressure. A guide member 13 is provided. The other end of the pressure conduit 10 is connected to the cylinder type actuator 11 (cylinder chamber 11a). Thus, the pressure conduit 10 is configured as a pipe that guides the positive pressure corresponding to the exhaust static pressure and the exhaust dynamic pressure to the cylinder type actuator 11.

The cylinder type actuator 11 is attached to the rear end plate 1b of the exhaust muffler 1 via an actuator attachment bracket 14, and its piston rod 11 is attached.
d is connected to a valve opening / closing lever 16 for rotating a valve shaft 15 of a butterfly valve type control valve 12.

The concrete structure of the cylinder type actuator 11 will be described with reference to FIG. 4. The cylinder type actuator 11 has a cylinder chamber 11 to which the pressure conduit 10 is connected.
a, a cup-seal type piston 11b that strokes according to the positive pressure level of the cylinder chamber 11a,
It has a spring 11c for urging the piston 11b in the valve fully closing direction, a piston rod 11d connected to the control valve 12, and a stopper 11e for restricting the stroke of the piston 11b.

The spring 11c is set so as to start moving when an exhaust pressure at an engine speed of about 1500 rpm or more acts on the cylinder chamber 11a.

The fluctuating pressure regulating member 17 is the pressure conduit 10
5 and its specific structure will be described with reference to FIG. 5. The one shown in FIG. 5 (a) is the orifice type variable pressure regulating member 17a, and the one shown in FIG. 5 (b) is the collar type. The fluctuating pressure regulating member 17b, the venturi type fluctuating pressure regulating member 17c shown in FIG. 5 (c), and the bead type fluctuating pressure regulating member 17d shown in FIG. 5 (d).

Next, the operation will be described.

[Valve opening / closing operation] When exhaust gas flows from the engine during traveling, the muffle line tube 4
A positive pressure corresponding to the exhaust pressure is introduced into the cylinder chamber 11a of the cylinder type actuator 11 via the pressure conduit 10. Then, since the piston 11b strokes in the cylinder chamber 11a according to this pressure level, the control valve 12 connected to the piston rod 11d of the cylinder type actuator 11 has a valve opening degree depending on the magnitude of this piston stroke. It is changed steplessly.

Here, the relationship between the pressure in the cylinder chamber 11a and the piston stroke is as shown in FIG. 7, due to internal friction of the cylinder type actuator 11 and the like.
There is a hysteresis characteristic when the pressure in 1a rises and the piston 11b advances, and when the pressure in the cylinder chamber 11a falls and the piston 11b returns.

Therefore, when the pressure in the cylinder chamber 11a fluctuates in a small width, the hysteresis pressure width becomes a dead zone, the piston stroke is held, and the opening / closing hunting of the control valve 12 is prevented.

Further, when the exhaust pressure is guided by the pressure conduit 10, a dynamic pressure guide member 13 for taking in the exhaust dynamic pressure is provided at the opening end on the muffle line tube side so as to oppose the flow of the exhaust gas flow. The pressure for driving the actuator 11 is (exhaust gas static pressure + exhaust gas dynamic pressure) (FIG. 6), and the pressure level is higher than in the case where only the exhaust gas static pressure is used as the driving pressure. Even if it is used, the piston stroke drive becomes reliable and stable.

[Pressure regulating action] Exhaust gas flows through the muffle linelet tube 4 while the gas pressure fluctuates at a cycle according to the number of engine cylinders and the number of revolutions. Therefore, when it is guided to the cylinder chamber 11a of the cylinder type actuator 11 as it is, the piston stroke fluctuates due to the pulsating pressure, and the opening / closing operation of the control valve 12 fluctuates. In particular, when a small-sized, low-pressure cylinder type actuator 11 is used, even if there is some pressure fluctuation, it responds to this, which makes it difficult to control the fluctuation of the opening / closing operation of the control valve 12.

On the other hand, since the fluctuating pressure regulating member 17 is provided in the middle of the pressure conduit 10, the flow passage cross-sectional area of the exhaust gas flow introduced from the muffle line tube 4 accompanied by the pulsation is narrowed, and the pulsation is reduced. The amplitude is smoothed. That is, since the pressure regulating action is exerted in the fluctuating pressure regulating member 17,
Fluctuations in the opening / closing operation of the control valve 12 are suppressed, and this pressure regulating action enables valve control particularly in a low engine speed region where pulsation is severe.

A means using a surge tank for converting dynamic pressure into static pressure is conceivable as means for suppressing this pressure fluctuation, but if this surge tank is adopted, it is disadvantageous in terms of space and cost.

[Control valve action during acceleration operation] When the pressure level of the exhaust pressure rises as the engine speed increases during the acceleration operation by stepping on the accelerator, the control valve 12 is gradually closed as described above. Since the valve opening is increased and the valve is continuously opened, a smooth feeling of acceleration and a comfortable acceleration exhaust sound can be obtained.

That is, as shown in the exhaust gas static pressure characteristic of FIG. 8, in the conventional valve on / off control (solid line), the engine speed is switched from valve closed to valve open during acceleration operation. In the region, the exhaust static pressure temporarily decreases, and a smooth feeling of acceleration cannot be obtained. However, in this embodiment (broken line), the control valve 12 has no valve opening according to the size of the piston stroke. As the engine speed is changed to the stage, the exhaust static pressure linearly increases as the engine speed increases, and the exhaust resistance gradually decreases to provide a smooth acceleration feeling. It should be noted that if the valve is completely closed (the one-dot diagonal line), the exhaust resistance becomes high in the high engine speed region, and the feeling of acceleration is insufficient.

Similarly, as shown in the exhaust sound characteristic of FIG.
The conventional valve full-open or full-valve on / off control (broken line) shows a characteristic that exhaust noise is temporarily reduced in the engine rotation region where the valve is switched from closed to open during acceleration operation. Although the acceleration exhaust noise is generated, in the present embodiment (solid line), the valve opening of the control valve 12 is continuously changed according to the size of the piston stroke, so that the exhaust noise is linear according to the engine speed. Increased,
You can get a comfortable acceleration exhaust sound. It should be noted that if the valve is completely closed (the one-dot diagonal line), the sound pressure in the high engine speed range becomes high and the acceleration exhaust sound becomes too high.

[When the system is applied to a vehicle] When the control type exhaust system is applied to a vehicle, a cylinder type actuator 11 driven by exhaust pressure is used as an actuator for controlling valve opening / closing provided in the exhaust system. Therefore, the cost of the system can be significantly reduced as compared with a system in which electronic control is performed using a motor actuator or a solenoid.

In addition, since the cylinder type actuator 11 having a smaller outer diameter than that of the diaphragm type actuator is used as the actuator, the system can be downsized, and with this downsizing, various layouts and installation spaces are required. The system can be shared among various vehicle types.

Next, the effect will be described.

(1) One end of the muffle linelet tube 4 of the exhaust system is opened, the pressure conduit 10 for guiding the exhaust pressure and the other end of the pressure conduit 10 are connected to the cylinder chamber 11a.
Cylinder type actuator 11 having piston 11b that strokes according to the pressure level of cylinder chamber 11a
And a control valve 12 which is connected to the piston rod 11d of the cylinder type actuator 11 and in which the valve opening is changed steplessly according to the size of the piston stroke. While achieving common use, it is possible to obtain a smooth feeling of acceleration and a pleasant acceleration exhaust sound during acceleration operation, and at the same time, it is possible to control valves in the low engine speed region while achieving cost and space advantages.

(2) Since the fluctuating pressure regulating member 17 is provided in the middle of the pressure conduit 10, it is possible to perform valve control in a low engine speed region while being advantageous in terms of cost and space that does not require a surge tank. be able to.

(3) Since the tapered dynamic pressure guide member 13 that takes in the exhaust gas dynamic pressure is provided at the opening end of the pressure conduit 10 on the muffle line tube side, the introduction efficiency of the exhaust gas dynamic pressure is provided. Therefore, even if the small-sized low-pressure type cylinder actuator 11 is used, the piston stroke drive can be made reliable and stable.

Although the embodiments have been described above with reference to the drawings, the specific structure is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, the butterfly valve type is shown as the control valve, but a shutter type valve or the like may be used as long as the valve opening can be changed steplessly.

In the embodiment, the example in which the cylinder type actuator is attached to the exhaust muffler is shown, but the mounting position of the cylinder type actuator is not limited to the position of the embodiment.

In the embodiment, an example in which a dynamic pressure guide member is provided is shown. For example, in the case where the pressure conduit is branched from the bent portion of the exhaust tube in the direction of the exhaust gas flow or with a slight inclination. Need not necessarily be provided with a dynamic pressure guide member.

[0057]

According to the first invention of claim 1,
In a control type exhaust system system in which a valve member for controlling exhaust pressure and exhaust sound is provided in the exhaust system, one end is opened to an exhaust tube on the upstream side of the muffler of the exhaust system, and a pressure conduit that guides a positive pressure according to the exhaust pressure. And a cylinder type actuator having the other end of the pressure conduit connected to the cylinder chamber and having a piston that strokes according to the pressure level of the cylinder chamber, and exhaust gas introduced in the middle of the pressure conduit and introduced from an exhaust tube. It is connected to a fluctuating pressure regulating member that regulates pressure fluctuation by narrowing the flow passage cross-sectional area, and the piston rod of the cylinder type actuator, and the valve opening is changed steplessly according to the size of the piston stroke. Since the control valve and the control valve are installed, cost reduction, downsizing, and sharing can be achieved while smooth acceleration feeling and comfortable addition during acceleration operation. Together with obtaining the exhaust sound, cost,
It is possible to obtain the effect that it is possible to enable valve control in the low engine speed region while making space advantages.

According to a second aspect of the present invention, in the controlled exhaust system according to the first aspect, the exhaust tube side opening of the pressure conduit is opposed to the exhaust gas flow of the exhaust tube. Since the apparatus is provided with the dynamic pressure guide member that takes in the exhaust dynamic pressure, the above effect can be obtained while increasing the dynamic pressure introduction efficiency.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a controlled exhaust system of the present invention.

FIG. 2 is a plan view showing a controlled exhaust system according to an embodiment.

FIG. 3 is an enlarged view of a main part of a control type exhaust system system according to an embodiment.

FIG. 4 is a partial cross-sectional view showing a cylinder type actuator of the embodiment system.

FIG. 5 is a diagram showing various modes of the variable pressure regulating member of the embodiment system.

FIG. 6 is a diagram comparing the static pressure + dynamic pressure characteristics with respect to the engine speed of the controlled exhaust system of the embodiment with the static pressure characteristics.

FIG. 7 is a stroke characteristic diagram showing the relationship between the pressure in the cylinder chamber and the piston stroke of the controlled exhaust system according to the embodiment.

FIG. 8 is an exhaust static pressure characteristic diagram showing the relationship between the engine speed and the exhaust static pressure of the control type exhaust system system of the embodiment.

FIG. 9 is an exhaust sound characteristic diagram showing the relationship between the engine speed and the exhaust sound of the controlled exhaust system of the embodiment.

[Explanation of symbols]

 a exhaust tube b pressure conduit c cylinder chamber d piston e cylinder type actuator f fluctuating pressure regulating member g piston rod h control valve

Claims (2)

[Claims] 1. A control type exhaust system system in which a valve member for controlling exhaust pressure and exhaust noise is provided in an exhaust system from an engine to a tail tube, wherein one end is opened to an exhaust tube on an upstream side of a muffler of the exhaust system, A pressure conduit that guides a positive pressure according to exhaust pressure, the other end of the pressure conduit is connected to a cylinder chamber, and a cylinder type actuator having a piston that strokes according to the pressure level of the cylinder chamber; A variable pressure regulating member which is provided and regulates pressure fluctuation by narrowing the flow passage cross-sectional area of the exhaust gas flow introduced from the exhaust tube, and is connected to the piston rod of the cylinder type actuator, and has a piston stroke size of A control type exhaust system system comprising: a control valve whose valve opening is continuously changed according to the control valve. 2. The controlled exhaust system according to claim 1, wherein a dynamic pressure guide member is provided at an opening of the pressure conduit on the exhaust tube side so as to face exhaust gas flow of the exhaust tube and take in exhaust gas dynamic pressure. A controlled exhaust system system characterized by the following.