WO2007119379A1

WO2007119379A1 - Exhaust pressure control valve

Info

Publication number: WO2007119379A1
Application number: PCT/JP2007/055272
Authority: WO
Inventors: Kimio Nemoto; Mitsuru Takeuchi; Yukihiro Harada; Koji Sakurai; Koichi Sugihara
Original assignee: Aisan Kogyo Kabushiki Kaisha
Priority date: 2006-03-15
Filing date: 2007-03-15
Publication date: 2007-10-25
Also published as: EP2003313B1; EP2003313A9; EP2003313A4; EP2003313A2

Abstract

Provided is an exhaust pressure control valve for controlling the pressure of an exhaust gas to be discharged from an engine. The exhaust pressure control valve reduces the unusual noises which will arise when a main valve is switched from a closed state to an open state. The exhaust pressure control valve (10) comprises a housing (11) having a main passage (12) and a bypass passage (28), a main valve (30) for switching a closed state to close the main passage (12) and an open state to open the main passage (12), and a bypass valve (26) for opening/closing the bypass passage (28). An inlet port (16) is formed in the inner wall face of the main passage (12) on the upstream side of the main valve. An outlet port (46) is formed in the inner wall face of the main passage (12) on the downstream side of the main valve. The upstream end of the bypass passage (28) is connected to the inlet port (16), and the downstream end of the bypass passage (28) is connected to the outlet port (46). The position of the outlet port (46) deviates in the circumferential direction from the position of that point on the circumferential edge of a valve member, at which the distance from the axis of the rotating shaft of the main valve to the circumferential edge of the valve member is the longest.

Description

Specification

Exhaust pressure control valve

Technical field

[0001] This application is filed with Japanese Patent Application No. 2006-70481 filed on March 15, 2006, Japanese Patent Application No. 2006-82528 filed on March 24, 2006, and 2006 Claims priority based on Japanese Patent Application No. 2006-84510 filed on March 27th. The entire contents of those applications are incorporated herein by reference.

The present invention relates to an exhaust pressure control valve that controls the pressure of exhaust gas exhausted from an engine.

Background art

[0003] An exhaust pressure control valve that controls the pressure of exhaust gas exhausted from the engine is used in order to improve the startability of the engine or purify exhaust gas from which engine power is also exhausted. International Publication No. 99Z41495 discloses a conventional exhaust pressure control valve.

This exhaust pressure control valve includes a housing provided with a main flow path and a bypass flow path. An inlet port and an outlet port are provided on the inner wall surface of the main channel. The upstream end of the binos passage is connected to the inlet port, and the downstream end of the binos passage is connected to the outlet port. A main valve for opening and closing the main channel is provided in the main channel. The main valve is disposed between the inlet port and the outlet port. The bypass channel is provided with a bypass nozzle that opens and closes the bypass channel. When the bypass valve is opened, the exhaust gas upstream of the main valve can flow downstream of the main valve through the nopass channel.

In this exhaust pressure control valve, the exhaust gas pressure increases when the opening of the main valve is reduced. When the exhaust gas pressure exceeds a predetermined value, the bypass valve opens. When the bypass valve opens, exhaust gas flows through the bypass flow path. As a result, the pressure increase of the exhaust gas is suppressed, and the pressure of the exhaust gas is maintained at a predetermined value. On the other hand, when the opening of the main valve is increased, the pressure of the exhaust gas decreases, the no-pass valve is closed and the bypass flow path is also closed. It is.

Disclosure of the invention

[0004] In recent years, the above-described exhaust pressure control valve can be applied to a diesel particulate filter system (hereinafter referred to as a DPF system! /) That purifies exhaust gas discharged from a diesel engine car. It is being considered. The DPF system is a system that collects particulates (particulate matter) and graphite contained in the exhaust gas of a diesel engine with a ceramic filter. In the DPF system, if the particulate matter (PM) mainly composed of soot collected by the filter exceeds a certain amount, the particulate matter (PM) mainly composed of soot collected by the filter is burned. Play the filter. An exhaust pressure control valve is used to regenerate this filter. That is, the exhaust pressure control valve is arranged upstream or downstream of the filter. When regenerating the filter, reduce the opening of the main valve and increase the pressure of the exhaust gas. When the exhaust gas pressure exceeds a predetermined value, the bypass valve opens and the exhaust gas flows through the no-pass passage. As a result, the pressure of the exhaust gas is maintained at a predetermined value. When the load on the engine increases due to increased exhaust gas pressure, the fuel supply to the engine increases. For this reason, the exhaust temperature is raised and the catalyst is activated, and a part of the fuel that is not burned by the engine is supplied to the acid catalyst upstream of the filter. The fuel supplied to the oxidation catalyst raises the exhaust gas temperature in the catalyst by an oxidation reaction, and burns particulate matter (PM) mainly composed of soot collected by the filter (that is, regenerates the filter). ) When the filter regeneration is complete, the main valve opens and the exhaust pressure drops to normal pressure. By controlling the exhaust gas pressure with the exhaust pressure control valve in this way, the filter can be regenerated using the fuel supplied to the engine.

However, when the exhaust pressure control valve is applied to the DPF system, the regeneration of the filter is terminated and the main valve is switched from the closed state (including the state where the main valve opening is reduced) to the open state. Exhaust gas rapidly flows from the upstream side to the downstream side of the main valve. As a result, there was a problem that unpleasant noise (squirting sound) was generated. In particular, vehicles equipped with diesel engines generate a lot of noise generated by large vehicles such as buses and trucks. For this reason, noise reduction has become a major issue.

[0005] An object of the present invention is to switch the main valve of the exhaust pressure control valve to a closed state force open state. It is an object to provide an exhaust pressure control valve that can reduce the noise generated during the operation.

[0006] In order to identify the cause of noise generated when the main valve is switched from the closed state to the open state, the present inventors performed a flow analysis simulation of the exhaust gas. As a result, when the main valve is switched from the closed state to the open state, the exhaust gas flowing at high speed from the upstream side to the downstream side of the main valve collides with the outlet port, generating a vortex in the exhaust gas in the outlet port. It was found that eddy currents contributed to noise.

Therefore, the exhaust pressure control valve of the present invention has a housing having a main flow path and a bypass flow path, a main valve for opening and closing the main flow path, and a bypass valve for opening and closing the bypass flow path. The main nozzle includes a throttle shaft that is rotatably supported by the housing, and a valve body that is attached to the throttle shaft. When the throttle shaft rotates, the valve body is switched between a closed state in which the main flow path is closed and an open state in which the valve body opens the main flow path. An inlet port to which the upstream end of the bypass channel is connected is provided on the inner wall surface of the main channel on the upstream side of the main valve. An outlet port to which the downstream end of the bypass flow path is connected is provided on the inner wall surface of the main flow path on the downstream side of the main valve. When the main valve is closed, the position of the outlet port and the axial force of the throttle shaft are shifted in the circumferential direction from the position of the point on the periphery of the valve body where the distance to the periphery of the valve body is the longest. Yes.

When the main valve is opened from the closed state, the axial force of the throttle shaft is at the point on the rim of the valve body where the distance to the rim of the valve body is the longest (that is, the point where the turning radius is the largest). The gap between the body periphery and the main channel is maximized, and the exhaust gas flow rate is also maximized. In this exhaust pressure control valve, the position of the outlet port and the position of the point on the peripheral edge of the valve body where the distance to the peripheral edge of the axial force valve body of the throttle shaft is longest are shifted in the circumferential direction. For this reason, the center of the high-speed exhaust gas flow that occurs when the main valve is closed deviates from the outlet port. As a result, noise generated when the main valve is closed can be suppressed.

[0007] In the exhaust pressure control valve described above, it is preferable that the position force in the circumferential direction of the outlet port substantially coincides with the position in the circumferential direction of the portion supporting the throttle shaft provided in the main flow path.

According to this configuration, since the exit port is disposed at a position away from the high-speed exhaust gas flow, the generated noise can be effectively suppressed. [0008] Further, the exhaust pressure control valve described above is housed in a through hole formed in the housing and supports one end of the throttle shaft, and one end of the throttle shaft on the side protruding from the through hole to the outside of the housing. It is preferable to further include an actuator that is attached to the shaft and rotationally drives the throttle shaft, and a seal member that seals between the throttle shaft and the inner wall surface of the through hole.

According to this configuration, the rotation operation of the throttle shaft can be performed smoothly and the outflow of exhaust gas from the main flow path can be suppressed.

[0009] It is also preferable that the outlet port is provided with flow characteristic changing means for changing the flow characteristic of the exhaust gas. If the outlet port is provided with flow characteristic changing means, even if the high-speed exhaust gas flow from the closed state to the open state flows toward the outlet port, the exhaust gas in the outlet port is changed. Generation of vortex is suppressed. As a result, noise generated when the main valve is closed can be reduced.

The flow characteristic changing means can be a curved wall surface formed on the downstream side of the outlet port. That is, by forming the wall surface on the downstream side of the outlet port in a curved surface, it is possible to suppress the generation of vortex in the outlet port.

Alternatively, the flow characteristic changing means can be a rectifying member that is attached to the wall surface on the downstream side of the outlet port and rectifies the flow of the exhaust gas. The rectifying member can also suppress the generation of vortex in the outlet port.

[0010] When an exhaust pressure control valve is used in a DPF system, a gap may be formed between the periphery of the valve element and the inner wall surface of the main flow path. In this case, when the main flow path is closed, the high-pressure exhaust gas upstream of the main valve flows at high speed from the gap between the peripheral edge of the valve body and the inner wall surface of the main flow path, and an ejection noise is generated.

As a result of investigating the cause of this sound by flow analysis simulation, the cause of the sound is mainly due to the difference in flow velocity between the exhaust gas flowing at high speed from the upstream side of the valve and the surrounding exhaust gas (downstream of the valve). It turned out to be. Therefore, if the flow rate of the exhaust gas flowing out from the upstream side of the valve to the downstream side can be kept low, the flow rate difference will be reduced and the jet noise can be reduced.

In order to reduce this blowing noise, the communication hole (surface force (For example, JP-A-2005-299457). By providing the communication hole in the valve body, the flow rate of the exhaust gas flowing through the gap between the peripheral edge of the valve body and the inner wall surface of the exhaust passage is reduced, and noise can be reduced to some extent. However, in the conventional technique, the communication hole provided in the valve body extends in parallel with the direction in which the exhaust passage extends. For this reason, the outflow direction of the exhaust gas flowing out from the peripheral edge of the valve body and the outflow direction of the exhaust gas flowing out downstream from the communication hole are parallel (the same), and the flows of both are difficult to be mixed. It was. Therefore, the difference in flow rate between the exhaust gas flow flowing from the upstream side of the main valve at high speed and the surrounding exhaust gas is not sufficiently relaxed, and the generated sound cannot be sufficiently reduced.

Therefore, in the exhaust pressure control valve according to one aspect of the present invention, a gap is formed around the entire periphery of the valve body at the periphery of the valve body and the inner wall surface of the main flow path with the valve closed. A communication hole penetrating the back surface is provided. The communication hole is provided such that the exhaust gas flowing out through the communication hole force in a state where the main valve is closed is inclined with respect to the axial direction of the main flow path.

According to this configuration, the flow of the exhaust gas flowing from the peripheral edge of the valve body to the downstream side and the flow of the exhaust gas flowing out from the communication hole are not parallel, so that both are easily mixed. For this reason, the flow velocity of the exhaust gas flowing out from the upstream side of the valve body to the downstream side is decelerated. As a result, it is possible to reduce the noise generated when the main valve is closed.

[0011] This exhaust pressure control valve can be configured such that the surface of the valve element is inclined with respect to the axial direction of the main flow path in a state where the valve is closed. In this case, it is preferable that the communication hole is provided at a position on the downstream side of the throttle shaft on the surface of the valve body in a direction substantially perpendicular to the surface of the valve body.

According to this configuration, the exhaust gas that has also flowed out of the communication hole is directed toward the center of the exhaust passage. For this reason, since the exhaust gas diffuses and flows throughout the exhaust passage, the flow rate of the exhaust gas can be effectively reduced. As a result, the effect of reducing the ejection noise can be improved.

[0012] In the exhaust pressure control valve, the inner wall surface of the main flow path on the downstream side of the main valve In addition, it is preferable to provide a gas flow rate reduction means (for example, a wire mesh or the like) for reducing the flow rate of the exhaust gas near the inner wall surface. Since the flow velocity of the exhaust gas flowing downstream from between the peripheral edge of the valve body and the inner wall surface of the exhaust flow path is reduced, the ejection noise can be further reduced.

Furthermore, the present invention provides an exhaust pressure control valve that can reduce noise generated when the main valve is switched from the closed state to the open state. The exhaust pressure control valve includes a housing including a main flow path and a bypass flow path, a main valve that opens and closes the main flow path, a first valve opening and closing device that opens and closes the main valve, and opens and closes the bypass flow path. It has a bypass valve and a second valve opening / closing device that opens and closes the binos valve. The first valve opening / closing device is set so that the time until the main valve is closed and the force is opened is longer than the time until the main valve is opened and the valve is closed. . For this reason, when the main valve is changed from the closed state to the open state, the exhaust gas is prevented from flowing rapidly from the upstream side to the downstream side of the main valve. As a result, noise (spout sound) can be reduced. Further, since the time until the main valve is opened and closed is set short, the exhaust gas pressure can be raised to a desired value in a short time.

[0014] In the exhaust pressure control valve described above, the first valve opening / closing device is operated by, for example, a solenoid, air, hydraulic pressure, etc., and can be opened / closed according to the operating state of the engine. The second valve opening / closing device can use, for example, a diaphragm type actuator, and is opened / closed according to the pressure of the exhaust gas upstream of the main valve. In this case, the first valve opening / closing device includes a diaphragm type actuator that opens and closes the main valve, a supply / exhaust means for supplying / exhausting gas to / from the pressure chamber of the actuator, and pressures of the supply / exhaust means and the actuator. A pipe connecting the chambers, a first state provided in the middle of the pipe and having a large passage cross-sectional area of the gas, and a second state having a small passage cross-sectional area of the gas and a second passage It is possible to have a flow rate adjusting means for switching to. The actuator is set to close the main valve when the gas pressure in the pressure chamber exceeds a predetermined pressure, and to open the main valve when the pressure in the pressure chamber is lower than the predetermined pressure. The flow rate adjusting means is in the first state when the gas is exhausted from the pressure chamber, and is in the second state when the gas is supplied to the pressure chamber. According to this configuration, when the pressure in the pressure chamber exceeds a predetermined pressure by supplying gas to the pressure chamber of the diaphragm type actuator, the main valve is in the closed state force open state. When the gas is supplied to the pressure chamber, the flow rate adjusting means becomes a passage opening with a small gas passage cross-sectional area, so that the pressure chamber pressure is prevented from rapidly increasing. For this reason, the main solenoid slowly opens. On the other hand, when the pressure chamber pressure gas of the diaphragm type actuator is exhausted and the pressure in the pressure chamber falls below a predetermined pressure, the main valve changes from the open state to the closed state. When the gas is exhausted from the pressure chamber, the flow rate adjusting means becomes a passage port having a large gas passage cross-sectional area, so that the pressure in the pressure chamber rapidly decreases. For this reason, the main valve is quickly closed.

[0015] The second valve opening / closing device includes a movable member that moves linearly according to the pressure of the exhaust gas upstream of the main valve, and a link mechanism that converts the linear motion of the movable member into an opening / closing motion of the bypass valve. And prefer to have, and.

According to this configuration, a linear motion corresponding to the exhaust gas pressure of the movable member is transmitted to the bypass valve via the link mechanism. For this reason, even when the exhaust gas pressure pulsates, the pulsation is dulled by the buffering effect of the diaphragm, so that the behavior of the bypass valve can be stabilized. As a result, the pressure of the exhaust gas can be accurately controlled.

[0016] The second valve opening / closing device includes, for example, a storage chamber that houses a movable member, an introduction pipe that introduces exhaust gas upstream of the main valve into one of the storage chambers partitioned by the movable member, An urging means arranged on the other side of the chamber to urge the movable member toward one of the accommodation chambers can be provided.

According to this configuration, the position of the movable member changes according to the pressure of the exhaust gas. For this reason

The opening degree of the noisy valve can be changed according to the exhaust gas pressure. According to this

The pressure of the exhaust gas can be controlled with high accuracy.

[0017] Further, it is preferable that a connection port to which a DPF device can be connected is provided at the upstream end of the housing.

According to this configuration, the exhaust pressure control valve is arranged downstream of the DPF device. For this reason,

Exhaust gas from which particulate matter (PM) containing soot as the main component is removed is exhaust pressure. It will flow through the force control valve. Therefore, particulate matter (PM) containing soot as a main component is prevented from adhering to the isotropic exhaust pressure control valve, and deterioration of the controllability of the exhaust pressure control valve is prevented.

[0018] A flange portion to which an exhaust pipe is attached can be provided at the downstream end of the housing. In this case, it is preferable that the flange portion is flexibly coupled to the exhaust pipe.

By flexibly coupling the exhaust pressure control valve and the exhaust pipe, it is possible to prevent the vibration of the upstream device (for example, engine) from being transmitted to the exhaust pipe.

[0019] Further, it is preferable that the bypass valve is disposed at a position where the main flow path is also retracted at an intermediate portion of the non-pass flow path. The second valve opening / closing device includes a movable member that linearly moves according to the pressure of the exhaust gas upstream of the main valve, and a link mechanism that converts the linear motion of the movable member into the opening / closing motion of the no-pass valve. It is preferable. According to this configuration, since the bypass valve force S is provided in the middle portion of the bypass flow path (that is, the position where the main flow path force is also retracted), it is prevented that the pressure of the exhaust gas flowing through the main flow path directly acts on the binos valve. The The binos valve is opened and closed by linearly moving the movable member in accordance with the pressure of the exhaust gas upstream of the main valve and transmitting the linear motion of the movable member to the bypass valve via the link mechanism. For this reason, even if the exhaust gas flowing in the main flow channel pulsates and the pressure of the exhaust gas upstream of the main valve fluctuates, it is possible to prevent the bypass valve from being greatly affected. As a result, chattering of the bypass valve can be prevented, and the exhaust gas pressure can be stably controlled.

Brief Description of Drawings

FIG. 1 is a diagram showing a configuration of an exhaust system of a diesel engine equipped with an exhaust pressure control valve of a first embodiment.

FIG. 2 is a cross-sectional view showing a schematic configuration of an exhaust pressure control valve of the first embodiment.

FIG. 3 is a sectional view taken along line III-III in FIG.

[Fig. 4] To explain the circumferential position of the bearing part of the inlet port, outlet port and throttle shaft Figure for.

圆 5] A diagram schematically showing a schematic configuration of a device for opening and closing the main valve.

6] A diagram schematically showing a schematic configuration of a device for opening and closing a bypass valve.

圆 7] Diagram showing the state of the flow control valve when closing the main valve.

FIG. 8 is a diagram schematically showing temporal changes in the pressure chamber pressure of the three-way solenoid valve and the actuator and the opening of the main valve.

[9] FIG. 9 is a diagram showing an example of a result of measuring a change in exhaust pressure and a change in sound pressure of the ejection sound when the state force when the main valve is closed is also opened.

圆 10] A graph showing the relationship between the response time of the main valve (the time until the closing force is fully opened) and the sound pressure (maximum sound pressure) of the erupting sound.

FIG. 11 is a view showing a modified example of the mounting structure of the exhaust pressure control valve and the exhaust pipe.

12] A view showing a modified example of the exhaust pressure control valve of the first embodiment.

FIG. 13 is a view showing another modification of the exhaust pressure control valve of the first embodiment.

FIG. 14 is a view showing another modification of the exhaust pressure control valve of the first embodiment.

15 is an enlarged view showing an outlet port of the exhaust pressure control valve shown in FIG.

16] Partially cutaway perspective view of another exhaust pressure control valve of the present invention.

[17] FIG. 17 is a partially broken perspective view of the exhaust pressure control valve shown in FIG. 16 as seen from different directions.

[FIG. 18] Inlet port 116, outlet port 146 and throttle shaft of exhaust pressure control valve shown in FIG.

Fig. 132 is a view of the bypass channel side.

FIG. 19 is an enlarged view showing a connection portion between the inlet port 116 and the main flow path 112.

FIG. 20 is an exhaust pressure control valve force of the second embodiment. FIG. 20 shows only the main flow path and the main nove.

FIG. 21 is an enlarged view of the periphery of the valve body and the inner wall surface of the main flow path.

FIG. 22 is a view showing a flow simulation result of the exhaust pressure control valve of the second embodiment.

FIG. 23 is a diagram showing the result of flow simulation in a case where a communication hole is provided.

FIG. 24 is a diagram showing a flow simulation result of a modification of the second embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described. (Form 1) The exhaust pressure control valve is arranged in the exhaust passage of the diesel engine. A DPF device is connected upstream of the exhaust pressure control valve, and an exhaust pipe (muffler) is connected downstream.

(Form 2) The exhaust pressure control valve has a housing provided with a main flow path and a bypass flow path. The no-pass channel is provided adjacent to the main channel. In the main channel, an inlet port is provided on the upstream side of the main valve, and an outlet port is provided on the downstream side of the main valve. The upstream end of the bypass channel is connected to the main channel via the inlet port, and the downstream end is connected to the main channel via the outlet port. The binos valve is placed in the middle of the binos channel.

(Mode 3) An opening / closing device that opens and closes the bypass valve includes a diaphragm type actuator and a link mechanism that converts linear motion of the rod of the actuator into opening / closing motion of the bypass valve.

(Form 4) The opening / closing device that opens and closes the main valve is equipped with a diaphragm type actuator. The main valve opens when the pressure in the pressure chamber of the actuator exceeds a predetermined pressure, and closes when the pressure in the pressure chamber of the actuator falls below a predetermined pressure. The pressure chamber of the actuator is connected to the neutral port of the 3-way solenoid valve, one of the other two ports of the 3-way solenoid valve is connected to the suction pump, and the other is open to the atmosphere. A flow control valve is installed between the pressure chamber of the actuator and the three-way solenoid valve.

(Form 5) The flow control valve has a housing and a partition plate that partitions the inside of the housing into an actuator side and a three-way solenoid valve side. A plurality of orifices are formed in the partition plate, and some of the plurality of orifices are opened and closed by a valve body (valve). The valve body closes the orifice when air is introduced into the pressure chamber of the actuator, and opens the orifice when air is exhausted from the pressure chamber of the actuator.

(Form 6) The main valve has a throttle shaft and a valve body attached to the throttle shaft. Both ends of the throttle shaft are rotatably supported by the housing. By rotating the throttle shaft, the valve body is switched between a closed state in which the main flow path is closed and an open state in which the valve body opens the main flow path. When the main valve is closed, the valve body is inclined with respect to the axial direction of the main flow path. (Form 7) The circumferential position of the outlet port is the axial force of the throttle shaft. The circumferential position of the point on the periphery of the valve body where the distance to the periphery of the valve body is the shortest (that is, the support part that supports the throttle shaft) It becomes the same as the position. The downstream wall of the outlet port is chamfered into a curved surface (R shape).

(Form 8) A flow straightening member (shielding plate, fin, hard cam, etc.) is arranged on the downstream wall of the outlet port.

(Form 9) The inlet port is formed in parallel with the throttle shaft. The inlet port is provided at a position displaced in the circumferential direction of the supporting portion force that supports the throttle shaft. Part of the inlet port and the throttle shaft overlap in the axial direction of the main flow path.

(Mode 10) When the main valve is closed, a gap is formed between the periphery of the valve body and the inner wall surface of the main flow path, and the valve body extends in the axial direction of the main flow path. It is inclined with respect to it.

(Form 11) The exhaust pressure control valve includes a housing having a main flow path and a bypass flow path, a throttle shaft that is rotatably supported by a housing, and a valve body attached to the throttle shaft. The valve body has a main valve that switches between a closed state in which the valve body closes the main flow path and an open state in which the valve body opens the main flow path by rotating the shaft, and a bypass valve that opens and closes the bypass flow path. An inlet port to which the upstream end of the bypass channel is connected is provided on the inner wall surface of the main channel on the upstream side of the main valve. An outlet port to which the downstream end of the bypass channel is connected is provided on the inner wall surface of the main channel on the downstream side of the main nozzle. The outlet port is provided with flow characteristic changing means for changing the flow characteristic of the exhaust gas.

(Mode 12) The exhaust pressure control valve includes a housing provided with an exhaust flow path, a rotating shaft rotatably supported by the housing, and a valve body attached to the rotating shaft, and rotates the rotating shaft. Thus, the valve body has a valve that switches between a closed state that closes the exhaust passage and an open state that opens the exhaust passage. The valve body is provided with a communication hole penetrating from the front surface to the back surface. The communication hole is provided so that the outflow direction of the exhaust gas flowing out of the communication hole force with the valve closed is inclined with respect to the axial direction of the exhaust passage. (Form 13) Exhaust pressure control valve has a housing provided with an exhaust flow path, and a housing. A rotating shaft that is rotatably supported and a valve body that is attached to the rotating shaft are provided. When the rotating shaft is rotated, the valve body closes the exhaust flow path and the open state opens the exhaust flow path. And a gas flow rate reduction means for reducing the flow rate of the exhaust gas near the inner wall surface, provided on the inner wall surface of the exhaust passage downstream from the valve.

(Form 14) The exhaust pressure control valve includes a housing including a main flow path and a bypass flow path, a main valve that opens and closes the main flow path, a first valve opening / closing device that opens and closes the main valve, and a bypass flow. A bypass valve that opens and closes the passage and a second valve opening and closing device that opens and closes the bypass valve are provided. The bypass valve is arranged at a position where the main channel force is also retracted in the middle of the nopass channel. The second valve opening / closing device includes a movable member that linearly moves in accordance with the exhaust gas pressure on the upstream side of the main valve, and a link mechanism that converts the linear movement of the movable member into an opening / closing motion of the bypass valve. Yes.

First Embodiment A first embodiment embodying the present invention will be described with reference to the drawings. First, the configuration of the exhaust system of the diesel engine 1 on which the exhaust pressure control valve 10 of this embodiment is mounted will be described.

As shown in FIG. 1, the exhaust system of the diesel engine 1 includes a DPF device 3 and an exhaust pressure control valve 10. The DPF device 3 has a filter (made of ceramic) that collects particulate matter (PM) mainly composed of soot contained in exhaust gas. A diesel engine 1 is connected to the upstream end of the DPF device 3 through an exhaust pipe 2. An exhaust pressure control valve 10 is connected to the downstream end of the DPF device 3 through an exhaust pipe 5. The exhaust pipe 2 is provided with a pressure sensor 2a. The pressure sensor 2a detects the pressure of the exhaust gas flowing through the exhaust pipe 2. The exhaust pipe 5 is provided with a pressure sensor 5a. The pressure sensor 5a detects the pressure of the exhaust gas flowing through the exhaust pipe 5. The exhaust gas pressure detected by the pressure sensors 2a and 5a is input to the ECU 4 (electronic control unit). The exhaust pressure control valve 10 controls the pressure of exhaust gas exhausted from the diesel engine 1. The downstream end of the exhaust pressure control valve 10 is connected to the muffler via the exhaust pipe 6! RU

The diesel engine 1 and the exhaust pressure control valve 10 are controlled by the ECU 4. The ECU 4 controls the intake air amount and the fuel supply amount to the diesel engine 1 according to the operation state of the diesel engine 1. ECU4 is detected by pressure sensors 2a and 5a. When the pressure difference between the pressures (that is, the pressure loss of the DPF device 3) exceeds a predetermined value, the main valve (described later) of the exhaust pressure control valve 10 is closed to regenerate the filter of the DPF device 3.

In the exhaust system described above, the exhaust gas exhausted from the diesel engine 1 flows to the DPF device 3 via the exhaust pipe 2. The DPF device 3 collects particulate matter (PM) mainly containing soot contained in the exhaust gas. The exhaust gas purified by the DPF device 3 is discharged from the muffler to the atmosphere through the exhaust pipe 5, the exhaust pressure control valve 10 and the exhaust pipe 6.

When particulate matter (PM) containing soot as a main component is collected in the DPF device 3 and the pressure loss of the DPF device 3 increases, the ECU 4 closes the main valve of the exhaust pressure control valve 10. As a result, the exhaust pressure of the diesel engine 1 increases, and the amount of fuel supplied to the diesel engine 1 increases in accordance with the increase of the exhaust pressure. For this reason, the gas containing unburned components is supplied to the 3D DPF device. Gas containing unburned components is supplied to the oxidation catalyst upstream of the filter. The unburned components supplied to the oxidation catalyst raise the gas temperature in the catalyst by an oxidation reaction. As a result, particulate matter (PM) mainly containing soot collected by the filter burns (that is, the filter of the DPF device 3 is regenerated). When regeneration of the filter of the DPF device 3 is completed, the ECU 4 opens the main valve of the exhaust pressure control valve 10 and returns to the normal operation state. The regeneration of the DPF device 3 is performed every time the pressure loss of the DPF device 3 exceeds a predetermined value.

Next, the exhaust pressure control valve 10 will be described. As shown in FIG. 2, the exhaust pressure control valve 10 includes a nosing 11 provided with a main flow path 12 and a bypass flow path 28, a main valve 30 that opens and closes the main flow path 12, and opens and closes the bypass flow path 28. A no-pass valve 26 is provided.

The nosing / housing 11 has a main flow path 12 and a binos flow path 28 (bypass chamber) provided adjacent to the main flow path 12. An exhaust pipe 5 is attached to the upstream end 14 of the main flow path 12. An exhaust pipe 6 is attached to the downstream end 66 of the main flow path 12 via a connecting pipe 70. An inlet port 16 and an outlet port 46 are formed on the inner wall surface of the main channel 12. The inlet port 16 is formed on the upstream end 14 side, and the outlet port 46 is formed on the downstream end 66 side. A main valve 30 is arranged between the inlet port 16 and the outlet port 46. The main valve 30 opens and closes the main flow path 12 between the inlet port 16 and the outlet port 46. [0026] The upstream end of the no-pass channel 28 is connected to the main channel 12 via the inlet port 16. The downstream end of the no-pass channel 28 is connected to the main channel 12 via the outlet port 46. A bypass valve 26 is accommodated in the bypass channel 28. The bypass valve 26 opens and closes an opening from the inlet port 16 to the bypass flow path 28. As is apparent from the figure, the bypass valve 26 is disposed at a position where the inner wall surface force of the main flow path 12 is also retracted.

[0027] As shown in FIG. 4, the throttle shaft 32 of the main valve 30 passes through the center (point O) of the main flow path 12, and both ends thereof are the wall surfaces of the main flow path 12 (point A of the nosing 11). Supported by C). As shown in FIG. 3, the circumferential position of the inlet port 16 is the same as the circumferential position of the bearing portion that supports one end of the throttle shaft 32 (point A or point C in FIG. 4). Similarly to the inlet port 16, the circumferential position of the outlet port 46 is the same as the circumferential position of the bearing portion that supports one end of the throttle shaft 32. Therefore, the main flow path 12 and the bypass flow path 28 extend substantially parallel (the axes are parallel)!

As shown in FIG. 3, the inlet port 16 has a circular cross section. By making the inlet port 16 circular in cross section, the inlet port 16 can be easily airtightly closed by a binos valve 26 (described later) (see Fig. 2). On the other hand, the outlet port 46 has a rectangular cross section. By making the outlet port 46 have a rectangular cross section, a large cross-sectional area of the outlet port 46 can be secured, and the exhaust gas can easily flow from the outlet port 46 to the main flow path 12. The inlet port 16 and the outlet port 46 are formed so as to be substantially orthogonal to the axis of the main flow path 12 (that is, the inlet port 16, the outlet port 46 and the throttle shaft 32 are parallel to each other). .)

Further, as shown in FIG. 2, the wall surface 48 on the downstream side of the outlet port 46 is chamfered in a curved surface shape (R shape) at the connection portion to the main flow path 12. As a result, the exhaust gas flowing through the main flow path 12 can easily flow to the downstream end 66 side.

[0028] As shown in FIG. 2, the main valve 30 is a butterfly valve. The main valve 30 includes a throttle shaft 32 and a valve body 34 attached to the throttle shaft 32. As the throttle shaft 32 rotates, the valve body 34 is switched between a closed state in which the main flow path 12 is closed and an open state in which the valve body 34 opens the main flow path 12. Valve body 34 with main flow path 12 closed Then, the valve body 34 is inclined with respect to the axis (center axis) of the main flow path 12 (see FIG. 3). A clearance is formed between the peripheral edge of the valve body 34 and the inner wall surface of the main flow path 12. This clearance is provided so that the diesel engine 1 can be operated even when the main valve 30 is closed. The clearance is formed over the entire circumference of the valve body 34.

[0029] One end of the throttle shaft 32 is rotatably supported by a bearing 40. The bearing 40 is accommodated in a mounting hole 42 formed in the housing 11. The mounting hole 42 is provided between the inlet port 16 and the outlet port 46. A throttle shaft 32 is inserted into one end of the mounting hole 42 (the end on the main flow path 12 side). The other end of the mounting hole 42 is open to the bypass channel 28, and the opening is closed by a cap 36. By closing the opening of the mounting hole 42 with the cap 36, particulate matter (PM) mainly composed of exhaust gas soot is prevented from entering the mounting hole 42.

The other end of the throttle shaft 32 is rotatably supported by a bearing 54. The bearing 54 is accommodated in a mounting hole 52 formed in the housing 11. A throttle shaft 32 is passed through one end of the mounting hole 52 (the end on the main flow path 12 side). A seal ring 50 is disposed between the throttle shaft 32 and the mounting hole 52. The seal ring 50 prevents the exhaust gas in the main flow path 12 from flowing out. The other end of the mounting hole 42 is open to the outside, and the drive end 32b of the throttle shaft 32 projects outside from the opening. The drive end 32 b of the throttle shaft 32 is coupled to the rod 60 of the actuator 64 via the coupling piece 62. As the rod 60 extends, the throttle shaft 32 rotates.

Next, the opening / closing device 41 that opens and closes the main valve 30 will be described with reference to FIG.

As shown in FIG. 5, the opening / closing device 41 includes an actuator 64, a three-way solenoid valve 47, and a vacuum pump 43.

The actuator 64 is a diaphragm type actuator. The actuator 64 includes a rod 60 that is displaced according to the pressure in a pressure chamber (not shown). One end of a connecting piece 62 is rotatably attached to the tip of the rod 60. The drive end 32b of the throttle shaft 32 is attached to the other end of the connecting piece 62. When rod 60 is displaced, The rottle shaft 32 rotates, whereby the main valve 30 is switched between an open state in which the main flow path 12 is opened and a closed state in which the main flow path 12 is closed. That is, when the pressure in the pressure chamber of the actuator 64 exceeds a predetermined pressure, the main valve 30 opens the main flow path 12, and when the pressure in the pressure chamber of the actuator 64 becomes equal to or lower than the predetermined pressure, the main valve 30 opens the main flow path 12. Close.

[0031] The pressure chamber of the actuator 64 is connected to the neutral port 47c of the three-way electromagnetic valve 47 through the pipe 57a, the flow rate control valve 51, and the pipe 57b. One port 47a of the remaining two ports 47a, 47b of the three-way solenoid valve 47 is connected to the vacuum pump 43 via the check valve 45. The other port 47b of the three-way solenoid valve 47 is open to the atmosphere. The check valve 45 prevents the backflow of air from the vacuum pump 43 to the three-way solenoid valve 47 side.

The three-way solenoid valve 47 is controlled by the ECU 4. When the neutral port 47c and the port 47a are in communication with each other by closing the port 47b and the vacuum pump 43 is operated, the air pressure in the pressure chamber of the actuator 64 is exhausted (this causes the main valve 30 to close). O On the other hand, if the port 47a is closed and the neutral port 47c and the port 47b communicate with each other, the atmosphere is introduced into the pressure chamber of the actuator 64 (so that the main valve 30 is opened). Become).

A flow control valve 51 is interposed between the pressure chamber of the actuator 64 and the three-way solenoid valve 47. The flow control valve 51 includes a housing 51, a partition wall 53 provided in the middle of the housing 51, and a valve body 55 attached to the partition wall 53. One chamber 51a partitioned by the partition wall 53 communicates with the pressure chamber of the actuator 64 through a pipe 57a. The other chamber 51b partitioned by the partition wall 53 is connected to a neutral port 47c of the three-way solenoid valve 47 through a pipe 57b.

The partition wall 53 has a plurality of orifices (through holes) 53a. Some of the plurality of orifices 53 a are opened and closed by the valve body 55. That is, when air is introduced into the pressure chamber of the actuator 64 (when air flows from the three-way solenoid valve 47 to the actuator 64, the valve element 55 closes a part of the orifice of the partition wall 53. When the pressure chamber force of the actuator 64 also exhausts air (when air flows from the actuator 64 to the three-way solenoid valve 47), Then, the valve body 55 is deformed to open the orifice 53a of the partition wall 53 (the state shown in FIG. 7). Therefore, when air is introduced into the pressure chamber of the actuator 64, the cross sectional area of the air is reduced, and air is slowly supplied to the pressure chamber of the actuator 64. On the other hand, when the pressure chamber force air of the actuator 64 is exhausted, the cross-sectional area of the air passage is increased, and the air in the pressure chamber of the actuator 64 is exhausted quickly. Thus, the time until the main valve 30 is changed from the closed state to the open state is adjusted to be longer than the time until the main valve 30 is also set to the closed state.

The bypass valve 26 is a flapper valve. The bypass valve 26 has a valve body 24 and a bolt 22 for attaching the valve body 24 to the arm 20. As shown in FIG. 6, an opening / closing device 69 for opening and closing the bypass valve 26 includes an actuator 79 and a link mechanism (73, 20) for transmitting the motion of the actuator 79 to the bypass valve 26! /.

The actuator 79 is a diaphragm type actuator. The actuator 79 includes a cylinder 81 and a rod 75. The rod 75 has a partition wall portion 75a provided at the base end portion thereof and a rod portion 75b provided upright on the partition wall portion 75a. The partition wall 75a is movably accommodated in the cylinder 81, and divides the cylinder 81 into a pressure chamber 77 and a spring accommodation chamber 83. The pressure chamber 77 is communicated with the exhaust pipe 5 by the exhaust gas introduction pipe 23, and the exhaust gas flowing through the exhaust pipe 5 is introduced into the pressure chamber 77. A spring 85 is accommodated in the spring accommodating chamber 83 in a compressed state. The spring 85 urges the partition wall 75a toward the pressure chamber 77. The base end of the link 73 is rotatably attached to the tip of the rod portion 75b. One end of the arm 20 is fixed to the tip of the link 73. A bypass valve 26 is attached to the other end of the arm 20.

When the pressure of the exhaust gas introduced into the pressure chamber 77 is below a predetermined pressure, the biasing force that biases the partition wall 75a of the spring 85 by the force acting on the partition wall 75a from the exhaust gas in the pressure chamber 77 Is bigger. Therefore, the rod 75 is in the initial position, and the bypass valve 26 closes the bypass flow path 28. On the other hand, when the pressure of the exhaust gas introduced into the pressure chamber 77 exceeds a predetermined pressure, the rod 75 extends against the biasing force of the spring 85. As a result, the arm 20 rotates around the shaft 18, and the bypass valve 26 attached to the tip of the arm 20 opens the bypass flow path 28. The operation when the exhaust pressure control valve 10 described above opens and closes the main valve 30 will be described. First, the operation when the main knob 30 is changed from the open state to the closed state will be described. As is clear from the above description, the atmosphere is introduced into the pressure chamber of the actuator 64 when the main valve 30 is open.

Opening and closing of the exhaust pressure control valve 10 is controlled by the ECU 4. The ECU 4 first outputs a drive signal to the three-way electromagnetic valve 47, closes the port 47b, and makes the neutral port 47c and the port 47a communicate with each other. The port 47a communicates with the negative pressure generated by the vacuum pump 43. As a result, the air in the pressure chamber of the actuator 64 is exhausted, and the main valve 30 closes the main flow path 12. When the pressure chamber force of the actuator 64 is also exhausted, the valve body 55 of the flow control valve 51 opens the orifice 53a. For this reason, the air in the pressure chamber of the actuator 64 is quickly exhausted.

[0035] When the main valve 30 closes the main flow path 12, the pressure of the exhaust gas increases, so the pressure of the exhaust gas introduced into the pressure chamber 77 of the actuator 79 that drives the bypass valve 26 also increases. When the pressure of the exhaust gas in the pressure chamber 77 exceeds a predetermined value, the rod 75 extends against the biasing force of the spring 85. As a result, the bypass valve 26 opens the bypass passage 28. The valve opening of the bino-nos lev 26 is determined by the pressure of the exhaust gas in the exhaust pipe 5, and the pressure of the exhaust gas in the exhaust pipe 5 increases as the pressure of the exhaust gas in the exhaust pipe 5 increases. The lower the value, the smaller. As a result, the pressure of the exhaust gas in the exhaust pipe 5 is maintained substantially constant.

Note that since the binos valve 26 is disposed at a position where the inner wall surface force of the main flow path 12 is also retracted, the exhaust pressure of the exhaust gas flowing through the main flow path 12 does not act directly. The bypass valve 26 is opened and closed by transmitting the linear motion of the actuator 79 to the arm 20 through the link mechanism. For these reasons, even when the exhaust gas flowing through the exhaust pipe 5 pulsates, the behavior of the bypass valve 26 is stabilized and the chattering of the bypass valve 26 can be prevented. As a result, the controllability of the exhaust pressure is enhanced.

Next, the operation when the main valve 30 is changed from the closed state to the opened state will be described. When changing the main valve 30 from the closed state to the open state, the ECU4 A drive signal is output to the valve 47, and the port 47a is closed so that the neutral port 47c and the port 47b communicate with each other. As a result, the atmosphere is also introduced into the pressure chamber of the actuator 64 on the side of the three-way solenoid valve 47, and the main valve 30 opens the main flow path 12. When air is introduced into the pressure chamber of the actuator 64, the valve body 55 of the flow control valve 51 closes some of the orifices 53a. For this reason, air is slowly introduced into the pressure chamber in the actuator 64, and the main nanoreb 30 is slowly opened.

[0037] FIG. 8 shows changes in the state of the three-way solenoid valve 47 when the main valve 30 is changed from the closed state to the open state, the pressure change in the pressure chamber of the actuator 64, and the valve of the main valve 30. It is a figure which shows the change of an opening degree typically.

As shown in FIG. 8, first, the three-way solenoid valve 47 is switched to the negative pressure state (the state where the actuator 64 and the vacuum pump 43 are connected), and the force is also switched to the atmospheric state (the state where the actuator 64 is opened to the atmosphere). . When the three-way solenoid valve 47 is switched to the atmosphere open state, the pressure chamber of the actuator 64 gradually shifts from the negative pressure state to the atmospheric pressure state. The main valve 30 begins to open gradually after a slight delay t after the timing force when the three-way solenoid valve 47 is switched to the open state. Then, when the time tO has elapsed since the timing of switching to the atmospheric release state, the main valve 30 is fully opened.

[0038] When the main valve 30 changes from the closed state to the open state, the exhaust gas flows from the upstream side to the downstream side of the main valve 30. Here, at the initial stage when the main valve 30 starts to open, the size of the gap between the peripheral edge of the valve body 34 and the inner wall surface of the main flow path 12 is from the axis of the throttle shaft 32 to the valve body 34 (peripheral point). Is proportional to the distance (rotation radius). That is, the axial force of the throttle shaft 32 also has the largest gap at points B and D where the distance to the valve body 34 (peripheral point) is the longest (see FIG. 4). Conversely, the gap is the smallest at points A and C where the distance to the axial force valve body 34 (peripheral point) of the throttle shaft 32 is the shortest. For this reason, the flow rate of the exhaust gas from which the main valve 30 also flows is the fastest at points B and D, and the slowest at points A and C. The outlet port 46 is provided at a point A (or a point C), and is arranged at a position shifted from a position where high-speed exhaust gas flows out. For this reason, the exhaust gas flowing out rapidly when the main valve 30 is opened is prevented from generating a vortex in the outlet port 46, and noise is prevented. Also, the downstream wall 48 of the outlet port 46 is curved. Thus, the exhaust gas flowing out from the main valve 30 can flow smoothly toward the downstream end 66. This also prevents the generation of vortex in the outlet port 46 and suppresses the generation of noise. Furthermore, since the main valve 30 is opened slowly, the exhaust gas is prevented from flowing out to the downstream side of the main valve 30 abruptly. This also suppresses the generation of noise.

When the main valve 30 opens the main flow path 12, the pressure of the exhaust gas flowing through the exhaust pipe 5 also decreases. For this reason, the no-pass valve 26 closes the bypass passage 28.

[0039] Further, in this embodiment, the flow control valve 49 is provided in the opening / closing device 41 that opens and closes the main valve 30, so that the main valve 30 gradually shifts from the closed state to the opened state. . As a result, the sound pressure of the generated noise (spout sound) is reduced.

FIG. 9 shows an example of the results of measuring the change in exhaust pressure and the change in sound pressure of the ejection sound when the main valve 30 is closed and the state force is also open. FIG. 9 also shows, as a comparative example, a change in the exhaust pressure when the flow control valve 49 is not applied and the force is applied. As can be seen from FIG. 9, when the flow control valve 49 is installed, the exhaust gas pressure change (Δ P / dt) is more gradual than when the flow control valve 49 is not used. Therefore, the time required for the state force when the main valve 30 is closed to the fully open state (so-called response time) also becomes longer. Also, as is clear from the comparison of the waveform of the exhaust gas pressure change and the sound pressure change waveform of the jet sound, there is a correlation between the magnitude of the exhaust gas pressure change and the sound pressure of the jet sound (the amplitude of the sound pressure). is there. Therefore, by making the pressure change of the exhaust gas moderate, the noise is reduced. That is, in the present embodiment, the ejection noise can be reduced by increasing the response time of the main valve 30.

FIG. 10 is a diagram showing the relationship between the response time of the main valve 30 (the time until the closed state force is also fully opened) and the sound pressure of the ejection sound (maximum sound pressure). As is apparent from the figure, by increasing the response time of the main valve 30, the maximum sound pressure of the ejected sound is reduced.

In the exhaust pressure control valve 10 of this embodiment, the circumferential position of the outlet port 46 and the circumferential position of the bearing portion of the throttle shaft 32 are the same, and the downstream wall surface 48 of the outlet port 46 is curved. Is formed. As a result, the generation of vortex in the exhaust gas in the outlet port 46 is suppressed, and the generation of noise can be effectively prevented. Further, by providing the flow control valve 49 in the opening / closing device 42 that opens and closes the main valve 30, the response time until the main noble 30 is changed from the closed state to the open state is lengthened. For this reason, the ejection sound when the main valve 30 is changed from the closed state to the open state is reduced. On the other hand, since the time until the main valve 30 is opened and closed is set short, the filter regeneration of the DPF device 3 can be performed without a time delay.

The bypass valve 26 is disposed at a position retracted from the main flow path 12, and the expansion / contraction motion of the rod of the actuator 79 is converted into the opening / closing operation of the bypass valve 26 by a link mechanism. Since the pulsation pressure is reduced by the buffering effect of the diaphragm of the actuator, even if the exhaust gas in the exhaust pipe 5 pulsates, the bypass valve 26 is prevented from chattering, and the exhaust pressure is kept within a predetermined pressure range. It becomes possible to control. In addition, since the opening of bino solenoid 26 changes in accordance with the change in exhaust gas pressure, the filter regeneration of DPF device 3 can be performed even when the vehicle is running (exhaust gas flow rate (pressure) changes). Can do.

In the above-described embodiment, the force transmitted from the movement of the actuator 79 to the binos valve 26 via the link mechanism is not limited to such a form. For example, the motion of the actuator may be converted into the opening / closing motion of the bypass valve using a rack and pion mechanism. Even with such a configuration, the opening degree of the bypass valve can be adjusted according to the exhaust pressure.

In the above-described embodiment, the connecting pipe 70 (exhaust pipe 6) is attached to the downstream end 66 of the main flow path 12 so as not to be displaceable. However, the present invention is not limited to such a form. For example, as shown in FIG. 11, an exhaust pipe 96 may be attached to the downstream end 93 of the main flow path in a flexible state (a state in which the exhaust pipe 96 can move relative to the downstream end 93). That is, the flange 94c is provided at the downstream end of the housing 90. The exhaust pipe 96 is also provided with a flange 87. The flange 94c and the flange 87 are connected by a bolt 89b and a weld nut 89d! A seal ring 89a is arranged between the flange 94c and the flange 87. A spring 89c is arranged in a compressed state between the flange 87 and the head of the bolt 89b. For this reason, the flange 87 is biased toward the flange 94c by the spring 89c, whereby the seal ring 89a is sandwiched between the flange 87 and the flange 94c. Seal ring 89a is graphite It has a certain degree of elasticity (deformability). Therefore, when a force acts between the housing 90 and the exhaust pipe 96, the seal ring 89a is deformed, and the position of the exhaust pipe 96 can be changed relative to the housing 90 (the downstream end 33 of the main flow path). . According to this configuration, the vibration of the device upstream of the exhaust pressure control valve (engine 1) is suppressed from being transmitted to the exhaust pipe 96, and the exhaust pipe 96 and the muffler can be prevented from vibrating.

Further, in the above-described embodiment, the force in which the wall surface 48 on the downstream side of the outlet port 46 is formed in a curved shape. The present invention is not limited to such a form. For example, as shown in FIG. 12, a hard cam 74 may be disposed in the opening 78 of the outlet port 46. By arranging the her cam 74 in the opening 78 of the outlet port 46, it is possible to prevent the vortex flow from being generated in the exhaust gas in the outlet port 46. Further, as shown in FIG. 13, a shielding plate 80 that covers the outlet port 46 may be provided so that the exhaust gas flow does not directly collide with the opening 82 of the outlet port 46. Alternatively, as shown in FIGS. 14 and 15, fins 84 may be provided on the wall surface 48 on the downstream side of the outlet port 46. Providing the fins 84 can also prevent eddy currents from occurring in the exhaust gas in the outlet port 46.

In the above-described embodiment, the bearing portions of the inlet port 16, the outlet port 46, and the throttle shaft 32 are arranged at the same position in the circumferential direction, but the present invention is not limited to such a form. For example, as shown in FIGS. 16 to 19, the bearing portions of the inlet port 116 and the throttle shaft 132 can be shifted in the circumferential direction.

In this case, as shown in FIGS. 16 to 18, it is preferable to arrange the bearing portions of the inlet port 116 and the throttle shaft 132 so as to overlap in the axial direction of the main flow path. By overlapping the inlet port 116 and the bearing portion of the throttle shaft 132 in the axial direction, the exhaust pressure control valve can be made compact. Further, as shown in FIG. 19, it is preferable to provide the inlet port 116 so as to protrude outward from the inner wall surface 112a of the main channel 112. Even if the bearings of the inlet port 116 and the throttle shaft 132 overlap in the axial direction, the inlet port 116 protrudes to the outside of the main channel 112 (lower side in FIG. 19). A sufficient road cross-sectional area can be secured.

Second Embodiment An exhaust pressure control valve according to the second embodiment will be described with reference to the drawings. Second implementation The exhaust pressure control valve in the example is configured in the same manner as the exhaust pressure control valve in the first embodiment, and differs from the first embodiment in that a communication hole is formed in the valve body of the main valve. Here, only the differences from the first embodiment will be described.

As shown in FIGS. 20 and 21, the valve body 237 force of the main valve 230 S When the main flow path 234 is closed, the valve body 237 is inclined with respect to the axis (center axis) C of the main flow path 234. Yes. A clearance 234d is formed between the peripheral edge of the valve element 237 and the inner wall surface of the main flow path 234. The clearance 234d is formed over the entire circumference of the valve body 237. The clearance 234d is preferably 0.5 mm or less. This is because if the clearance exceeds 234d force .5mm, the effect of increasing the exhaust pressure cannot be fully exhibited.

The valve body 237 is formed with one communication hole 237a that penetrates the surface force of the valve body 237 by directing it toward the back surface. The communication hole 237a is formed on the downstream side of the rotary shaft (throttle shaft) 238 when the valve body 237 closes the main flow path 234. The communication hole 237a is provided substantially perpendicular to the surface of the valve body 237.

Further, a wire mesh 290 is disposed on the inner wall surface of the main flow path 234 at a position downstream of the main valve 236. The wire mesh 290 is arranged over the entire circumference of the inner wall surface of the main flow path 234.

When the main valve 230 chain flow path 234 is closed, the exhaust gas upstream of the main valve 230 has a clearance 234d between the peripheral edge of the valve body 237 and the inner wall surface of the main flow path 234 and the valve body 237. It flows out from the communication hole 237a to the downstream side of the main valve 230. At this time, the exhaust gas flowing out from the clearance 234d flows out in parallel with the axial direction C of the main flow path 234. The exhaust gas flowing out from the communication hole 237a flows out toward the center of the main flow path 234 (that is, flows out in a direction inclined with respect to the axial direction C). For this reason, the exhaust gas flowing out from the clearance 234d and the exhaust gas flowing out from the communication hole 237a are mixed efficiently, and the flow velocity is reduced.

Further, the exhaust gas flowing out from the communication hole 237a flows toward the center of the main flow path 234, and the diameter of the communication hole 237a is increased by using one communication hole 237a. It flows out from the communication hole 237a. For this reason, the exhaust gas flowing out from the communication hole 237a is easily diffused throughout the main flow path 234, and the flow velocity is reduced. Further, a wire mesh 290 is arranged on the inner wall surface of the main flow path 234 on the downstream side of the main valve 230. For this reason, the flow velocity of the exhaust gas flowing out from the clearance 234d is reduced by the wire mesh 290.

As a result, the noise generated when the main flow path 234 is closed by the main valve 230 is suppressed to a low level.

FIG. 22 shows the result of simulating the flow state of the exhaust gas when the main valve 230 is closed for the exhaust pressure control valve of the present embodiment. FIG. 23 shows the result of simulating the flow state of exhaust gas when the main valve is closed by the exhaust pressure control valve with a communication hole provided in the valve body of the main valve.

As is clear from the comparison between FIGS. 22 and 23, in the exhaust pressure control valve of the present embodiment, the exhaust gas flows out of the main flow path 234 by the exhaust gas flowing out from the communication hole 237a, and the clearance 234d It can be seen that the flow rate of the exhaust gas flowing out is kept low.

[0048] In the exhaust pressure control valve of the second embodiment, when the main valve 230 is closed, the exhaust gas flowing out from the clearance 234d and the exhaust gas flowing out from the communication hole 237a are mixed efficiently, and the flow velocity is kept low. . Further, the exhaust gas flowing out from the communication hole 237a into the main flow path 234 flows out toward the center of the main flow path 234 and spreads over the entire main flow path 234. For this reason, the flow velocity of the exhaust gas flowing out from the communication hole 237a can be kept low. Furthermore, the flow rate of the exhaust gas flowing out from the clearance 234d is kept low by the metal mesh 290 provided on the inner wall surface of the main flow path 234. As a result, the difference in flow velocity between the gas flow flowing out from the clearance 234d and the gas flow flowing out from the communication hole 237a and the surrounding exhaust gas is reduced, and the jet noise can be reduced.

[0049] In the embodiment described above, there is only one communication hole 237a provided in the valve body 237. The present invention is not limited to such a form. For example, a plurality of communication holes provided in the valve body can be provided. By providing a plurality of communication holes, exhaust gas can be diffused throughout the main flow path, and the flow velocity difference can be reduced. When providing a plurality of communication holes, it is preferable to reduce the diameter of each communication hole. By reducing the communication hole, it is possible to keep the exhaust gas flow rate from the communication hole low while keeping the exhaust gas leakage flow rate constant. Fig. 24 shows the simulation results of the flow state when a plurality of communication holes are provided in the valve body. As can be seen from FIG. 24, even when a plurality of communication holes are provided in the valve body, the exhaust gas diffuses throughout the main flow path, and the flow velocity is kept low. In the example shown in FIG. 24, the downstream end side of the communication hole is chamfered, and the downstream end side of the peripheral edge of the valve body is chamfered. This makes it easier for the exhaust gas flowing out of the upstream side of the main nozzle to diffuse, contributing to a reduction in the flow velocity.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of purposes at the same time, and attaining one of the purposes itself has technical usefulness.

Claims

The scope of the claims

[1] Engine power An exhaust pressure control valve for controlling the pressure of exhaust gas to be exhausted, a housing including a main flow path and a bypass flow path,

A throttle shaft rotatably supported by the housing and a valve body attached to the throttle shaft are provided. When the throttle shaft is rotated, the valve body closes the main flow path and the valve body is the main flow path. A main valve that switches to an open state that opens,

A no-pass valve that opens and closes the no-pass flow path, and

An inlet port to which the upstream end of the bypass channel is connected is provided on the inner wall surface of the main channel upstream of the main valve.

An outlet port to which the downstream end of the bypass flow path is connected is provided on the inner wall surface of the main flow path on the downstream side of the main valve.

When the main valve is closed, the position of the outlet port and the position of the point on the rim of the valve body where the distance from the axis of the throttle shaft to the rim of the valve body is the longest and the exhaust pressure deviated in the circumferential direction. Control valve.

[2] The exhaust pressure control valve according to claim 1, wherein the position force in the circumferential direction of the outlet port substantially coincides with the position in the circumferential direction of the portion supporting the throttle shaft provided in the main flow path.

[3] A bearing that is accommodated in a through hole formed in the housing and supports one end of the throttle shaft, and an actuator that is attached to one end of the throttle shaft that protrudes outside the through hole force housing and rotates the throttle shaft The exhaust pressure control valve according to claim 1 or 2, further comprising: a seal member that seals between the throttle shaft and the inner wall surface of the through hole.

[4] The outlet port is provided with flow characteristic changing means for changing the exhaust gas flow characteristic.

V, the exhaust pressure control valve of any one of claims 1 to 3.

5. The exhaust pressure control valve according to claim 4, wherein the flow characteristic changing means is a curved wall surface formed on the downstream side of the outlet port.

6. The exhaust pressure control valve according to claim 4, wherein the flow characteristic changing means is a rectifying member that is attached to a wall surface on the downstream side of the outlet port and rectifies the flow of the exhaust gas.

[7] When the main valve is closed, a gap is formed around the entire circumference of the periphery of the valve body and the inner wall surface of the main flow path. The valve body is provided with a communication hole that penetrates from the front surface to the back surface. The communication hole is configured so that the direction of exhaust gas flowing out when the main valve is closed is the axis of the main flow path. The exhaust pressure control valve according to any one of claims 1 to 6, wherein the exhaust pressure control valve is provided to be inclined with respect to a direction.

[8] When the main valve is closed, the surface of the valve body is inclined with respect to the axial direction of the main flow path, and the communication hole is located at a position downstream of the throttle shaft on the surface of the valve body. The exhaust pressure control valve according to claim 7, wherein the exhaust pressure control valve is provided in a direction substantially perpendicular to the surface of the valve body.

[9] The exhaust pressure control valve according to any one of claims 1 to 8, further comprising a gas flow rate reducing means provided on an inner wall surface of the main flow channel downstream of the main valve, for reducing the flow rate of the exhaust gas in the vicinity of the inner wall surface. .

10. The exhaust pressure control valve according to claim 9, wherein the gas flow velocity reducing means is a wire mesh.

[11] Engine power An exhaust pressure control valve for controlling the pressure of exhaust gas to be exhausted, comprising a housing having a main flow path and a bypass flow path,

A no-pass valve that opens and closes the no-pass flow path, and

An exhaust pressure control valve provided with flow characteristic changing means for changing the flow characteristic of the exhaust gas at the outlet port.

[12] Engine power An exhaust pressure control valve for controlling the pressure of exhaust gas to be exhausted, a housing provided with an exhaust flow path,

A rotating shaft that is rotatably supported by the housing and a valve body attached to the rotating shaft are provided. By rotating the rotating shaft, the valve body force exhaust passage is closed and the exhaust passage is opened. A valve that switches to a state, The valve body is provided with a communication hole penetrating from the front surface to the back surface. The communication hole is configured so that the exhaust gas flowing out of the communication hole force is in the axial direction of the exhaust flow path when the valve is closed. An exhaust pressure control valve provided so as to be inclined with respect to the exhaust pressure control valve.

[13] Engine power An exhaust pressure control valve for controlling the pressure of exhaust gas to be exhausted, a housing provided with an exhaust flow path,

A rotating shaft that is rotatably supported by the housing and a valve body attached to the rotating shaft are provided. By rotating the rotating shaft, the valve body force exhaust passage is closed and the exhaust passage is opened. A valve that switches to a state,

An exhaust pressure control valve having gas flow rate reducing means provided on the inner wall surface of the exhaust flow channel downstream of the valve and reducing the flow rate of exhaust gas in the vicinity of the inner wall surface.

[14] Engine power An exhaust pressure control valve that controls the pressure of exhaust gas to be exhausted, a housing including a main flow path and a bypass flow path;

A main valve that opens and closes the main flow path;

A first valve opening / closing device that opens and closes the main valve;

A noisy valve that opens and closes the noisy flow path,

A first valve opening / closing device that opens and closes the noisy valve, and the first valve opening / closing device closes the main valve and opens the main valve. An exhaust pressure control valve that is set to be longer than the time it takes to reach a state.

[15] The first valve opening and closing device

A diaphragm type actuator that opens and closes the main valve;

Supply / exhaust means for supplying / exhausting gas to / from the pressure chamber of the actuator;

Piping connecting the air supply / exhaust means and the pressure chamber of the actuator;

A flow rate adjusting means is provided in the middle of the pipe and switches between a first state where the gas passage cross-sectional area is a large passage port and a second state where the gas passage cross-sectional area is a small passage port. And

The actuator is set to close the main valve when the gas pressure in the pressure chamber exceeds a predetermined pressure, and to open the main valve when the pressure in the pressure chamber is lower than the predetermined pressure. The

15. The exhaust pressure control valve according to claim 14, wherein the flow rate adjusting means is in a first state when exhausting gas from the pressure chamber and in a second state when supplying gas to the pressure chamber.

[16] The second valve opening / closing device includes a movable member that linearly moves according to the pressure of the exhaust gas upstream of the main valve, and a link mechanism that converts the linear motion of the movable member into the opening / closing motion of the bypass valve. The exhaust pressure control valve according to claim 14 or 15, further comprising:

[17] The second valve opening / closing device includes a storage chamber that houses the movable member, an introduction pipe that introduces exhaust gas upstream of the main valve into one of the storage chambers partitioned by the movable member, and the other of the storage chambers. The exhaust pressure control valve according to claim 16, further comprising: an urging means arranged to urge the movable member toward one side of the accommodation chamber.

[18] The exhaust pressure control valve according to claim 16 or 17, wherein a connection port to which a DPF device can be connected is provided at the upstream end of the wing.

[19] The flange further includes a flange portion provided at the downstream end of the housing to which the exhaust pipe is attached. The flange portion is configured so that the flange portion and the exhaust pipe are flexibly coupled. The exhaust pressure control valve according to any one of claims 14 to 18.

[20] Engine power An exhaust pressure control valve for controlling the pressure of exhaust gas to be exhausted, comprising a housing having a main flow path and a bypass flow path,

A main valve that opens and closes the main flow path;

A first valve opening / closing device that opens and closes the main valve;

A noisy valve that opens and closes the noisy flow path,

A second valve opening / closing device that drives the opening and closing of the noisy valve, and the noisy valve is disposed at a position retracted from the main channel force in the middle of the binos channel,

The second valve opening / closing device includes a movable member that linearly moves according to the exhaust gas pressure upstream of the main valve, and a link mechanism that converts the linear motion of the movable member into an opening / closing motion of the bypass valve. Exhaust pressure control valve.