JP6097753B2 - Valve device and secondary air introduction device - Google Patents

Description

  The present invention relates to a secondary air introducing device for exhaust gas purification measures of, for example, a gasoline engine, and a valve device used therefor.

  2. Description of the Related Art A secondary air introduction device that supplies secondary air into exhaust gas and reburns unburned components contained in the exhaust gas is known as a countermeasure for exhaust gas purification of a gasoline engine. In the valve device used in such a secondary air introduction device, the reed valve is opened using the pulsation of the exhaust gas flow in the exhaust system to supply the secondary air.

  In the conventional secondary air introduction device, when there is a possibility of overheating of the exhaust system due to the supply of secondary air, such as during high-speed and high-load operation, regardless of the pulsation of the exhaust gas flow, The secondary air is not supplied. However, if no secondary air is supplied in this way, there will be no cooling effect due to the flow of secondary air, and the reed valve will be overheated due to the conduction and radiation of exhaust heat, resulting in poor durability, and emissions. It gets worse.

  Therefore, as shown in Patent Document 1 below, in order to prevent overheating of the reed valve, it has been proposed to provide a small hole through which a small amount of air constantly flows in the direction of the reed valve.

  However, such a conventional device is convenient for cooling the reed valve because air is constantly flowing even in a small amount, but in the situation where so-called afterburn is likely to occur, afterburn is effectively prevented. It was difficult to do.

  Further, as shown in Patent Document 2 and Patent Document 3, a secondary air control device having a valve structure that operates with a pressure cylinder on the secondary air supply side of a reed valve is known.

  However, in such a configuration, when the supply of secondary air is stopped and the exhaust gas flows backward, exhaust concentrated water accumulates near the reed valve, and the reed valve is corroded or already closed. There is a possibility that the seal portion is deteriorated in an attempt to further push up the valve portion. When the seal portion is deteriorated, the sealing performance is deteriorated, and there is a possibility that the air cleaner mounted on the secondary air supply side is corroded.

Japanese Utility Model Publication No. 57-17050 JP 2001-227506 A JP 2002-38938 A

  The present invention has been made in view of such a situation, and an object of the present invention is to reduce inconvenience due to the backflow of exhaust gas even if the exhaust gas flows backward when the supply of secondary air is stopped. It is to provide a valve device and a secondary air introduction device.

In order to achieve the above object, a valve device according to the present invention comprises:
An inlet port into which the main fluid is introduced, an outlet port through which the main fluid is discharged, and a casing having a communication flow path connecting the inlet port and the outlet port;
A reed valve portion provided on the outlet port side of the communication flow path inside the casing;
A valve device having a shut valve portion provided on the inlet port side of the communication flow path inside the casing,
The shut valve portion is
A drive rod having one end connected to the diaphragm and movable in the axial direction in accordance with a pressure difference between the first pressure chamber and the second pressure chamber partitioned by the diaphragm;
A shut valve main body fixed to the rod and moving in the axial direction together with the rod,
Inside the casing,
A first valve that fully closes the communication flow path when the first valve portion of the shut valve body abuts at a first closed position in which the drive rod has moved to the inlet port side to the maximum along the axial direction. Zodiac,
At the second closed position where the drive rod has moved to the second pressure chamber side to the maximum along the axial direction, the second valve portion of the shut valve body abuts and at least the main flow path of the communication flow path is completely removed. A second valve seat that is closed,
In the axial position of the drive rod located between the first closed position and the second closed position, the shut valve body is configured to fully open the communication flow path,
A through hole is formed in the casing to connect the communication flow path located on the reed valve portion side with respect to the second valve seat and the second pressure chamber;
When the drive rod is in the first closed position, fluid pressure from the outlet port acts on the second pressure chamber, and the drive rod can be forcibly moved to the second closed position. It is characterized by that.

  The valve device according to the present invention can be suitably used as a secondary air introduction device for exhaust gas purification measures. That is, when a relatively large amount of secondary air (an example of the main fluid) is sent from the outlet port to the exhaust gas system to promote exhaust gas purification, the drive rod is moved in the axial direction to fully open the shut valve body. To position.

  Further, when there is a high possibility that afterburning will occur in the exhaust system, the drive rod is moved in the axial direction to the first closed position, and the shut valve body is brought to the fully closed position. As a result, the supply of air to the exhaust system is completely shut off, and the possibility of afterburning can be greatly reduced.

  Moreover, in the valve device according to the present invention, in order to stop the inflow of the secondary air from the inlet port, when the drive rod is in the first closed position, the backflow of exhaust gas from the outlet port has occurred. In addition, the fluid pressure from the outlet port acts on the second pressure chamber through the through hole, forcibly moving the drive rod to the second closed position.

  As a result, inflow of secondary air, which is the main fluid from the inlet port, can be prevented, but in the process in which the drive lot moves from the first closed position to the second closed position, the valve is opened, and the secondary air, which is the main fluid. Allowed to flow into the outlet port. Therefore, it is possible to reduce the concentration of exhaust gas that flows backward from the outlet port, and to expect the effect of pushing back the backward flow.

  Therefore, according to the valve device of the present invention, even if a backflow of exhaust gas or the like occurs from the outlet port, corrosion of the reed valve can be prevented in order to reduce the concentration of exhaust gas. Further, since the communication between the inlet port and the outlet port is shut off after the exhaust gas is pushed back, the seal portion is hardly deteriorated, has excellent sealing properties, and does not corrode the air cleaner connected to the inlet port.

In the present invention, inside the casing, in the middle of the communication flow path from the inlet port to the reed valve portion, a main opening constituting the main flow path and an opening area smaller than the main opening. A sub-opening that constitutes the sub-channel may be provided,
In the position where the second valve portion of the shut valve main body abuts on the second valve seat, the flow of fluid from the inlet port to the lead portion is allowed through the sub flow path of the sub opening. Also good.

  With this configuration, there is a possibility that afterburn may occur in the exhaust system, but if this is not possible, or if the temperature of the reed valve part exceeds the set temperature, the drive rod is moved to the second closed position. It is possible to move the shut valve main body to a small flow position by moving it in the axial direction. This makes it possible to flow a small amount of air in the direction of the reed valve, and it is easy to prevent overheating of the reed valve.

  Preferably, a second valve seat is formed outside the main opening.

FIG. 1A is a schematic cross-sectional view of a valve device according to an embodiment of the present invention, showing a fully open position of the shut valve. FIG. 1B shows a first closed position of the shut valve body in the valve device shown in FIG. 1A. FIG. 1C shows a second closed position of the shut valve body in the valve device shown in FIG. 1A. FIG. 1D shows a second closed position of the shut valve body in a valve device according to another embodiment of the present invention. FIG. 2 shows a secondary air introduction device in which the valve device shown in FIG. 1A is used.

First Embodiment Hereinafter, the present invention will be described based on the embodiments shown in the drawings.
The valve device 2 shown in FIGS. 1A to 1C is used as a secondary air introduction device 100 for purifying exhaust gas in the exhaust system piping 64 of the gasoline engine 60 shown in FIG. An intake system pipe 62 is connected to an intake port 61 of an engine 60 mounted on a vehicle or the like, and an exhaust system pipe 64 is connected to the exhaust port 63.

  The valve device 2 has an inlet port 6 and an outlet port 8, and the outlet port 8 is connected to an exhaust system pipe 64 through a secondary air supply pipe 70. The outside air purified by an air cleaner (not shown) is introduced into the valve device 2 from the inlet port 6, and the valve operation of the valve device 2 causes the outlet port 8 according to the exhaust pulsation in the exhaust system pipe 64. The secondary air is selectively supplied into the exhaust system pipe 64 through the through hole.

  As shown in FIGS. 1A to 1C, the valve device 2 includes a casing 4 that internally configures a communication flow path 10 extending from the inlet port 6 to the outlet port 8. The casing 4 includes a casing main body 4a having a communication channel 10 formed therein, an inlet port cover 4b that is attached to the casing main body 4a and forms the inlet port 6, and an outlet port cover 4c that forms the outlet port 8. And a pressure chamber cover 4d constituting a pressure chamber 14 which is distinguished from the communication flow path 10.

  In the present embodiment, the communication channel 10 is provided so that the axis of the inlet port 6 and the axis of the outlet port 8 are substantially orthogonal. A reed valve portion 12 is provided in the vicinity of a connection portion where the outlet port cover 4c constituting the outlet port 8 is attached to the casing body 4a. In the communication flow path 10 between the reed valve portion 12 and the inlet port 6, A shut valve portion 16 is provided.

  The reed valve portion 12 opens according to the pulsation of the exhaust gas flow in the exhaust system pipe 64 shown in FIG. 2, and the secondary air taken in from the inlet port 6 passes through the outlet port 8 and the secondary air supply pipe 70 to the exhaust system. Supply to the pipe 64. The shut valve portion 16 will be described later.

  Inside the casing body 4a, a partition wall 4f for forming the main opening 10a is formed in the middle of the communication flow path 10 from the inlet port 6 to the outlet port 8.

  The center of the main opening 10a substantially coincides with the axis of the drive rod 30 and also substantially coincides with the axis of the inlet port 6, and the drive rod 30 is disposed inside the communication channel 10 including the main opening 10a. Is mounted by a bearing 32 so as to be movable in the axial direction. The bearing 32 is fixed to a partition wall 4e provided integrally within the casing body 4a. The partition wall 4e partitions the pressure chamber 14 and the communication channel 10.

  The central portion of the disk-shaped diaphragm 20 is fixed to the first end portion 30 a in the axial direction of the drive rod 30 together with the central portions of the pair of disk-shaped retainers 18 that sandwich the diaphragm 20. The outer edge of the diaphragm 20 is fixed to a connecting portion where the pressure chamber cover 4d is attached to the upper end of the casing body 4a. The diaphragm 20 separates the pressure chamber 14 into a first pressure chamber 14a and a second pressure chamber 14b. It is.

  A connecting pipe 16 is connected to the pressure chamber cover 4d provided to cover the first pressure chamber 14a. A throttle hole 18 is formed at the tip of the connecting pipe 16. The throttle hole 18 of the connection pipe communicates with the intake system pipe 62 shown in FIG. 2 through a pipe (not shown), and the internal pressure of the intake system pipe 62 is introduced into the first pressure chamber 14a, and the second pressure Due to the pressure difference with the chamber 14b, the diaphragm 20 is deformed as shown in FIGS. 1A to 1C, and the drive rod 30 is moved in the axial direction.

  The throttle hole 18 may be connected to a fluid pressure control device or the like instead of the intake system pipe 62 shown in FIG. The second pressure chamber 14b is a sealed space in the present embodiment, but may be communicated with atmospheric pressure.

  As shown in FIGS. 1A to 1C, a central portion of a disc-shaped shut valve main body 40 constituting the shut valve portion 16 is fixed to the second end portion 30 b which is the lower end of the drive rod 30. The shut valve body 40 is fixed to the second end portion of the drive rod 30 by a pair of retainers 41, and the lower end of the coil spring 34 is in contact with the upper retainer 41. The upper end of the spring 34 is in contact with the lower surface of the partition wall 4e of the casing body 4a, and the spring force of the spring 34 causes the valve body 40 to move downward together with the drive rod 30 in the axial direction relative to the casing body 4a. It can be pressed.

  A ring-shaped first convex portion 42 as a first valve portion is formed on the outer peripheral side lower surface of the valve body 40. As shown in FIG. 1B, when the pressure in the first pressure chamber 14a is maximized compared to the pressure in the second pressure chamber 14b, and the drive rod 30 is moved to the lowest end position in the axial direction, The ring-shaped first convex portion 42 of the valve body 40 is in pressure contact with the first valve seat 52 formed on the inner surface of the inlet port cover 4b, and completely blocks the communication between the inlet port 6 and the communication flow path 10 ( Fully closed at the first closed position).

  A ring-shaped second convex portion 44 as a second valve portion is formed on the outer peripheral side upper surface of the valve body 40. As shown in FIG. 1C, in a state where the pressure in the first pressure chamber 14a is maximally smaller than the pressure in the second pressure chamber 14b and the drive rod 30 is moved to the uppermost end position in the axial direction, The ring-shaped second convex portion 44 of the valve body 40 is in pressure contact with the second valve seat 54 formed on the lower surface of the partition wall 4f constituting the main opening 10a described above, and closes the main flow path of the main opening 10a. (Fully closed at the second closed position).

  As shown in FIG. 1A, in the state where the pressures of the first pressure chamber 14a and the second pressure chamber 14b are balanced, the valve body 40 of the drive rod 30 connected to the diaphragm 20 has the first valve seat 52 and It is located at an intermediate position with respect to the second valve seat 54. Therefore, the valve body 40 opens the main opening 10a and also opens the inlet port 6. The air taken in from the inlet port 6 is exhausted from the outlet port 8 as shown in FIG. The secondary air can be supplied into the system pipe 64 at the maximum flow rate.

  In this embodiment, the material of each member which comprises the valve apparatus 2 is not specifically limited, It is comprised with a metal, rubber | gum, a synthetic resin, etc. However, preferably, the diaphragm 20 is made of a flexible member such as a thin metal plate, synthetic resin or rubber, the valve body 40 is made of an elastic member such as synthetic resin or rubber, and the covers 4b, 4c and 4d are It is made of metal.

  In the present embodiment, the partition wall 4e provided integrally inside the casing body 4a has a communication channel 10 located near the reed valve portion 12 between the second valve seat 54 and the reed valve portion 12. And a second pressure chamber 14b of the pressure chamber 14 is formed. The through hole 50 may be single or plural, but the inner diameter of the through hole 50 is preferably 1.6 to 8.6% of the hole diameter of the reed valve portion.

  The valve device 2 according to the present embodiment can be suitably used as the secondary air introduction device 100 for exhaust gas purification countermeasures shown in FIG. That is, when a relatively large amount of secondary air is sent from the outlet port 8 to the exhaust system pipe 70 to promote purification of exhaust gas, an intermediate pressure is introduced into the first pressure chamber 14a, as shown in FIG. 1A. The pressure in the first pressure chamber 14a and the second pressure chamber 14b is balanced to bring the shut valve body 40 into the fully open position.

  Further, when there is a high possibility of afterburning in the exhaust system pipe 64 shown in FIG. 2, a pressure higher than the intermediate pressure is introduced into the first pressure chamber 14a. As a result, as shown in FIG. 1B, the diaphragm 20 is pushed down from the first pressure chamber 14a toward the second pressure chamber 14b, the drive rod 30 is moved in the axial direction, and the shut valve body 40 is moved to the first closed position (all Close). As a result, the inlet port 6 is completely blocked, the supply of air to the exhaust system pipe 64 through the outlet port 8 is completely shut off, and the possibility of afterburning can be made extremely low.

  In this state, even if a backflow of the exhaust gas from the outlet port 8 through the reed valve portion 12 to the inside of the casing 4 occurs, the fluid pressure based on the backflow of the exhaust gas from the outlet port 8 passes through the through hole 50. Acting on the second pressure chamber 14b, the drive rod 30 is forcibly moved to the second closed position as shown in FIG. 1C. Therefore, the ring-shaped second convex portion 44 of the valve body 40 is in pressure contact with the second valve seat 54 formed on the lower surface of the partition wall 4f constituting the main opening 10a, and closes the main flow path of the main opening 10a. (Fully closed at the second closed position).

  As a result, inflow of secondary air, which is the main fluid, from the inlet port 6 can be prevented, but the shut valve opens and is the main fluid in the process in which the drive rod 30 moves from the first closed position to the second closed position. Allow the secondary air to flow into the outlet port 8. Therefore, it is possible to reduce the concentration of exhaust gas and the like flowing backward from the outlet port 8 and to expect the effect of pushing back the backward flow.

  Therefore, according to the valve device 2 of the present embodiment, even if a backflow of exhaust gas or the like occurs from the outlet port 8, corrosion of the reed valve 12 can be prevented in order to reduce the concentration of exhaust gas. Further, since the communication between the inlet port 6 and the outlet port 8 is interrupted after the backflow of the exhaust gas is pushed back, the ring-shaped second convex portion 44 that is a seal portion is less deteriorated and has excellent sealing properties. Do not corrode connected air cleaners.

Second Embodiment As shown in FIG. 1D, in this embodiment, the partition 4f for forming the main opening 10a has a sub-opening 10b in addition to the main opening 10a. Except being formed in the outer peripheral position, it is the same as that of 1st Embodiment, and there exists the same effect except being shown below. The sub-opening 10b formed in the partition wall 4f has an opening area that is 1/28 to 1/34 of the opening area of the main opening 10a, and is sufficiently smaller than the main opening 10a. There is no need for a single sub-opening 10b, and a plurality of sub-openings 10b may be formed. In addition, the opening area of the sub-opening 10 b is preferably smaller than the through hole 50.

  Also in this embodiment, even if a backflow of exhaust gas from the outlet port 8 through the reed valve portion 12 to the inside of the casing 4 occurs, the fluid pressure based on the backflow of exhaust gas from the outlet port 8 passes through the through hole 50. Acting on the second pressure chamber 14b, as shown in FIG. 1D, the drive rod 30 is forcibly moved to the second closed position. Therefore, the ring-shaped second convex portion 44 of the valve body 40 is in pressure contact with the second valve seat 54 formed on the lower surface of the partition wall 4f constituting the main opening 10a, and closes the main flow path of the main opening 10a. (Second closed position).

  However, in this state, the sub-opening 10b formed in the partition wall 4f is formed outside the main opening 10a (and outside the valve main body 40), so that it is not blocked by the valve main body 40, and the sub-opening. Communication of the communication flow path 10 from the inlet port 6 toward the reed valve 12 is ensured through the portion 10b.

  As a result, in the present embodiment, only the sub-opening 10b is opened, and the shut valve main body 40 is set to the small flow position. As a result, a small amount of air can flow from the inlet port 6 to the reed valve portion 12 through the sub-opening portion 10b, and it is easy to prevent the reed valve portion 12 from being overheated.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.
For example, the valve device 2 according to the present invention can be applied not only to the secondary air introduction device 100 shown in FIG. 2 but also to other devices.

  The valve device according to the present invention is used, for example, as a secondary air introduction device for purifying exhaust gas in exhaust system piping of a gasoline engine.

DESCRIPTION OF SYMBOLS 2 ... Valve apparatus 4 ... Casing 4a ... Casing main body 4b ... Inlet port cover 4c ... Outlet port cover 4d ... Pressure chamber cover 4f ... Partition 6 ... Inlet port 8 ... Outlet port 10 ... Connecting flow path 10a ... Main opening 10b ... Sub Opening portion 12 ... Reed valve portion 14 ... Pressure chamber 14a ... First pressure chamber 14b ... Second pressure chamber 16 ... Shut valve portion 20 ... Diaphragm 30 ... Drive rod 34 ... Spring 40 ... Shut valve body 50 ... Through hole 52 ... First 1 valve seat 54 ... 2nd valve seat 60 ... engine 62 ... intake system piping 64 ... exhaust system piping 70 ... secondary air supply piping 100 ... secondary air introduction device

Claims (4)

An inlet port into which the main fluid is introduced, an outlet port through which the main fluid is discharged, and a casing having a communication flow path connecting the inlet port and the outlet port;
A reed valve portion provided on the outlet port side of the communication flow path inside the casing;
A valve device having a shut valve portion provided on the inlet port side of the communication flow path inside the casing,
The shut valve portion is
A drive rod having one end connected to the diaphragm and being movable in the axial direction according to the pressure of the first pressure chamber and the second pressure chamber partitioned by the diaphragm;
Anda shutoff valve body to move axially with said drive rod is fixed to the drive rod,
Inside the casing,
A main opening that constitutes a main flow path in the middle of the communication flow path from the inlet port to the reed valve portion, and a sub flow path that is disposed outside the main opening and has a smaller opening area than the main opening. A partition wall provided with a sub-opening that constitutes
The first valve portion of the shut valve body abuts against the inner surface of the inlet port at the first closed position where the drive rod has moved to the inlet port side along the axial direction to the maximum extent, and the communication flow path is entirely A first valve seat to be closed;
The second valve portion of the shut valve main body abuts against the partition wall at the second closed position where the drive rod has moved to the second pressure chamber side to the maximum along the axial direction, and the main flow path of the main opening portion And a second valve seat that does not close the sub-opening ,
In the position where the shut valve main body abuts on the second valve seat, fluid flow from the inlet port to the reed valve portion is allowed through the sub flow path of the sub opening,
In the axial position of the drive rod located between the first closed position and the second closed position, the shut valve body is configured to fully open the communication flow path,
A through hole is formed in the casing to connect the communication flow path located on the reed valve portion side with respect to the second valve seat and the second pressure chamber;
When the drive rod is in the first closed position, fluid pressure from the outlet port acts on the second pressure chamber, and the drive rod can be forcibly moved to the second closed position. A valve device characterized by that. 2. The valve device according to claim 1, wherein the sub-opening formed in the partition has an opening area of 1/28 to 1/34 of an opening area of the main opening . Wherein Ri main opening of and the outside second valve seat formed tare, the second valve seat valve according the to claim 1 or 2 sub opening is formed in said partition wall positioned outside apparatus.   The secondary air introduction apparatus which has the valve apparatus in any one of Claims 1-3.

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