JPH08232636A - Control-type exhaust system - Google Patents

Abstract

PURPOSE: To realize smooth acceleration feeling by continuously changing the valve opening by a cylinder-type actuator housing a piston to be stroked in the valve opening direction according to the pressure level in a cylinder chamber, in an exhaust system in which a valve member for controlling exhaust pressure and exhaust sound is provided. CONSTITUTION: When exhaust gas is allowed to flow from an engine in traveling, pressure corresponding to the exhaust pressure from a muffler inlet tube 4 is trapped by a dynamic guide member 13 and guided into a cylinder chamber 11a of a cylinder-type actuator 11 through a pressure conduit 10. Since a piston 11b is stroked in the cylinder chamber 11a according to the pressure level, a control valve 12 connected to a piston rod 11d of the actuator 11 changes the valve opening continuously according to the amount of the piston stroke. In this case, since the cylinder inner surface is taken as a resin coating surface 11f, the smooth piston operation having no stick slip is obtained.

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 sharing, a smooth acceleration feeling and a comfortable acceleration exhaust sound are obtained during acceleration operation, and the piston built-in pressure adjustment function and valve fail-safe function are provided in the spring built into the actuator. It is to have it together.

A second object of the present invention is to secure a smooth piston operation and prevent pressure leakage while maintaining the first object.
To achieve the purpose of.

[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, one end is opened to an exhaust tube a or a muffler b of the exhaust system, and a pressure conduit c for guiding exhaust pressure by positive pressure or negative pressure; The other end of c is connected to the cylinder chamber d, and a piston e that strokes in the valve opening direction according to the pressure level of the cylinder chamber d
And a cylinder type actuator g having a built-in spring f for urging the piston e in the valve closing direction, and a valve opening / closing member i directly connected to a piston rod h of the cylinder type actuator g, depending on the size of the piston stroke. Control valve j whose valve opening is changed steplessly
And characterized in that:

In order to achieve the above-mentioned second object, in the invention of claim 2, as shown in the claim correspondence diagram of FIG. 1, in the control type exhaust system system of claim 1, the piston of the cylinder type actuator g is The inner surface of the cylinder on which e slides is a resin coated surface k that reduces the piston sliding friction.

[0015]

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

During traveling, the positive pressure or negative pressure corresponding to the exhaust pressure from the exhaust tube a or the muffler b of the exhaust system due to the exhaust gas from the engine enters the cylinder chamber c of the cylinder type actuator g through the pressure conduit c. Be guided. Then, since the piston e makes a stroke in the cylinder chamber c according to this pressure level, the control valve j connected to the piston rod h of the cylinder type actuator g has a valve opening degree according to 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 j 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 g having an outer diameter 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.

In the valve opening / closing drive control, the exhaust pressure when the piston e starts the stroke and the control valve j shifts from the valve closed to the valve open is the spring force of the spring f built in the cylinder type actuator g. It is set by determining the size of. That is, the spring f
Has a piston working pressure adjusting function.

On the other hand, since the valve opening / closing member i is directly connected to the piston rod h of the cylinder type actuator g, the spring force of the spring f directly acts on the control valve j, and the urging force of the spring f is exerted. Is applied in the valve closing direction, so that in the event of a pressure leak failure due to damage to the pressure conduit c, the control valve j is forcibly closed by the biasing force of the spring f. That is, the spring f has a valve fail-safe function of ensuring valve closing, which is the safe side when a failure occurs, in addition to the piston operating pressure adjusting function.

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

In the valve opening / closing drive control, the piston e of the cylinder type actuator g slides back and forth according to the magnitude of exhaust pressure. At this time, the piston e and the inner surface of the cylinder are in contact with each other, and the inner surface of the cylinder is the resin coating surface k that reduces the sliding friction of the piston. Therefore, smooth piston operation without stick slip is ensured. In addition, wear and damage on the inner surface of the cylinder due to friction with the piston e can be suppressed to a small level, and pressure leakage from the sliding portion between the piston e and the inner surface of the cylinder can be prevented.

[0025]

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 an embodiment of the present invention, FIG. 3 is an enlarged view of a main part of the control type exhaust system system according to an embodiment of the present invention, and FIG. FIG.

2 and 3, 1 is an exhaust muffler (corresponding to the muffler b), 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, 1
0 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, and 16 is a valve opening / closing lever (corresponding to the valve opening / closing operation member i).

The exhaust muffler 1 has a front end plate 1a and a rear end plate 1b. The front end plate 1a passes through a muffle linelet tube 4 into which exhaust gas from an engine (not shown) enters and the inside of the muffler. A first muffler outlet tube 5 for discharging exhaust gas is connected, and a second muffler outlet tube 6 for adjusting exhaust gas discharge by controlling opening / closing of the control valve 12 is connected to the rear end plate 1b.

One end of the pressure conduit 10 is opened in the exhaust muffler 1, and a tapered dynamic pressure guide for taking in exhaust dynamic pressure is provided at the opening end so as to face the flow of the exhaust gas flow from the muffle linelet tube 4. A 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 mounting bracket 14, and its piston rod 11 is attached.
d is directly connected via a pin to a valve opening / closing lever 16 for rotating the valve shaft 15 of the 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,
A spring 11c for urging the piston 11b in the valve fully closing direction, a piston rod 11d connected to the control valve 12, a stopper 11e for restricting the stroke of the piston 11b, and a resin coating surface 11f for reducing piston sliding friction are provided. It is configured to have.

The spring force of the spring 11c is set so that the spring 11c starts to move when an exhaust pressure of about 1500 rpm or more acts on the cylinder chamber 11a.

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. 5, 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), and the pressure level is higher than in the case where only the exhaust gas static pressure is used as the driving pressure, and even if a compact, low pressure type cylinder actuator 11 is used. The piston stroke drive becomes reliable and stable.

[Pressure Control Function] Exhaust gas flows through the muffle linelet tube 4 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 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, the pressure conduit 10 is connected to the exhaust muffler 1.
The exhaust gas introduced from the muffle line tube 4 into the exhaust muffler 1 expands at the same time as it is introduced into the exhaust muffler 1 because the exhaust pressure is guided from the internal chamber of Due to this, a pressure regulating action is exhibited in the exhaust muffler 1. This pressure regulating action suppresses fluctuations in the opening / closing operation of the control valve 12, and in particular,
Valve control is possible in the low engine speed range where pulsation is severe. When the inner diameter of the pressure conduit 10 is set to be small, the pulsation having an amplitude larger than the inner diameter is regulated by the contraction flow, and the pulsation pressure is smoothed by the double pressure regulation action by the expansion and contraction flow.

[Operation of control valve during acceleration operation] When the pressure level of the exhaust pressure rises as the engine speed increases during acceleration operation by depressing 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. 6, in the conventional on / off control of the valve fully open or valve fully closed (solid line), the engine rotation is switched from the valve closed to the valve open during the 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.

Further, since the cylinder type actuator 11 installed on the rear end plate 1b of the exhaust muffler 1 is adapted to introduce the exhaust pressure from the exhaust muffler 1, the pipe length of the pressure conduit 10 is shortened. As is clear from 2 and FIG. 3, the control valve system is compactly housed in the rear position of the exhaust muffler 1, and the system can be further downsized.

[Spring Function] In the valve opening / closing drive control, the exhaust pressure when the piston 11b starts the stroke and the control valve 12 shifts from the valve closed to the valve open is the spring built in the cylinder type actuator 11. It is set by determining the magnitude of the spring force of 11c. That is, the spring 11c has a function of adjusting the piston operating pressure according to the vehicle type and the like.

On the other hand, since the valve opening / closing lever 16 is directly connected to the piston rod 11d of the cylinder type actuator 11, the spring force of the spring 11c is controlled by the control valve 1.
2 also acts directly on the spring 2, and the biasing force of the spring 11c is applied in the valve closing direction.
The control valve 12 is forcibly closed by the urging force of 1c.

That is, the spring 11c has a valve fail-safe function for ensuring valve closing, which is the safe side in the event of a failure, in addition to the piston operating pressure adjusting function.

Since the spring 11c is built in the cylinder type actuator 11, it is protected without the need for a spring cover.

On the other hand, in the case of an actuator for controlling the opening / closing of a servomotor by rotating the servomotor with a wire (Japanese Patent Laid-Open No. 3-185209, etc.), the return spring for ensuring the valve closure is the control valve. Located on the valve shaft, the servomotor only functions to provide the force to open the valve. Therefore, it is necessary to provide two springs, a servo motor built-in spring and a return spring, and a spring cover is required to protect the return spring.

[Piston Sliding Action] In the valve opening / closing drive control, the piston 11b of the cylinder type actuator 11 slides back and forth according to the magnitude of exhaust pressure. At this time, the piston 11b and the inner surface of the cylinder serve as a contact sliding surface, but since the inner surface of the cylinder is the resin coating surface 11f that reduces the piston sliding friction, a smooth piston operation without stick slip is ensured. In addition, wear and damage on the inner surface of the cylinder due to friction with the piston 11b is suppressed to a small level, and leakage of pressure from the sliding portion between the piston 11b and the inner surface of the cylinder is prevented.

Next, the effect will be described.

(1) A pressure conduit 10 having one end opened to the exhaust muffler 1 of the exhaust system to guide the exhaust pressure, and the pressure conduit 10
The other end of the cylinder chamber 11a is connected to the cylinder chamber 11a.
A cylinder type actuator 11 having a piston 11b that strokes in the valve opening direction according to the pressure level of a.
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 comfortable acceleration exhaust sound during acceleration operation.

(2) Since the pressure conduit 10 is a pipe which opens at one end into the inner chamber of the exhaust muffler 1 and guides the exhaust pressure, a surge tank is not required and the pressure regulating action is exerted in the exhaust muffler 1. The fluctuation in the opening / closing operation of the control valve 12 is suppressed, and valve control is possible even in the low engine speed region.

(3) Since the cylinder type actuator 11 for introducing the exhaust pressure from the exhaust muffler 1 is attached to the exhaust muffler 1 via the bracket 14, the pipe length of the pressure conduit 10 is shortened and the system is further miniaturized. Can be achieved.

(4) At the exhaust muffler side opening end of the pressure conduit 10, there is provided a tapered dynamic pressure guide member 13 that opposes the flow of the exhaust gas flow from the muffle linelet tube 4 and takes in the exhaust dynamic pressure. The introduction efficiency of dynamic pressure has increased,
Even if the compact, low-pressure type cylinder actuator 11 is used, the piston stroke drive can be made reliable and stable.

(5) The cylinder type actuator 11 has a spring 1 for urging the piston 11b in the valve closing direction.
A cylinder type actuator 11 with a built-in 1c
Since the valve opening / closing lever 16 is directly connected to the piston rod 11d, the spring 11c built in the actuator 11 can have both the piston working pressure adjusting function and the valve fail-safe function.

(6) Since the inner surface of the cylinder, which is the sliding contact surface with the piston 11b, is the resin coating surface 11f that reduces the piston sliding friction, it is necessary to ensure smooth piston operation and prevent pressure leakage. You can

Although the embodiments have been described above with reference to the drawings, the specific configuration 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 example of the cylinder type actuator 11 which operates by positive exhaust pressure is shown, but it is also applicable to a system using a cylinder type actuator which operates by negative exhaust pressure.

In the embodiment, one end of the pressure conduit is opened in the exhaust muffler, but it may be opened in the exhaust tube.

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, an 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.

[0065]

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 or muffler of the exhaust system, and a pressure conduit for guiding exhaust pressure by positive pressure or negative pressure is provided. The other end of the pressure conduit is connected to a cylinder chamber, a piston that strokes in the valve opening direction according to the pressure level of the cylinder chamber, and a cylinder type actuator that incorporates a spring that biases the piston in the valve closing direction, Since the valve opening / closing member is directly connected to the piston rod of the cylinder-type actuator, and the control valve that changes the valve opening steplessly according to the size of the piston stroke is provided, the cost is reduced and the size is reduced. ， Achieves common use while obtaining a smooth acceleration feeling and comfortable acceleration exhaust sound while accelerating. Effect that the piston working pressure adjusting function spring that is built with the valve fail-safe function can be provided together on.

According to a second aspect of the present invention, in the control type exhaust system system according to the first aspect, a resin for reducing the piston sliding friction is provided on the inner surface of the cylinder on which the piston of the cylinder type actuator slides. Since the surface is coated, the above effect can be obtained while ensuring smooth piston operation and preventing pressure leakage.

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

FIG. 7 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 muffler c pressure conduit d cylinder chamber e piston f spring g cylinder type actuator h piston rod i valve opening / closing member j control valve

Claims (2)

[Claims] 1. In a control type exhaust system system in which a valve member for controlling exhaust pressure and exhaust sound is provided in an exhaust system from an engine to a tail tube, one end is opened to an exhaust tube or a muffler of the exhaust system, and a positive pressure is applied. Alternatively, a pressure conduit that guides exhaust pressure due to negative pressure, the other end of the pressure conduit is connected to a cylinder chamber, and a piston that strokes in the valve opening direction according to the pressure level of the cylinder chamber, and the piston is attached in the valve closing direction. A cylinder type actuator having a built-in spring, and a control valve in which a valve opening / closing member is directly connected to the piston rod of the cylinder type actuator, and the valve opening is continuously changed according to the size of the piston stroke. A controlled exhaust system that is equipped. 2. The controlled exhaust system according to claim 1, wherein an inner surface of the cylinder on which the piston of the cylinder actuator slides is a resin coating surface that reduces piston sliding friction. System.