JP2007154907A - Valve opening and closing controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve loading property of an actuator for opening and driving a flap type valve 5 onto a vehicle such as an automobile by preventing increase of size of the actuator. <P>SOLUTION: A whole periphery flap part 93 is provided at the whole periphery of the flap type valve 5 by bending a peripheral fringe part of the flap type valve 5 stored in the inside of a housing 4 connected with an EGR cooler openably and closably onto a first seal face side. Consequently, since flow of EGR gas having high flow velocity occurs on a surface of the valve and flow of EGR gas having low flow velocity occurs on a rear surface of the valve when opening the flap type valve 5 by the negative pressure operation type actuator, difference between pressure on the front surface and pressure on the rear surface of the valve occurs and lift is generated in the direction for assisting in the direction of opening of the flap type valve 5. As a result, since required operation shaft force of the negative pressure operation type actuator can be reduced without enlarging diameter of a diaphragm, a loading space can be easily ensured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a valve opening / closing control device having a valve driving device for opening or closing a valve of an opening / closing valve or a switching valve, and in particular, using a displacement of a diaphragm of a negative pressure actuated actuator to provide two positions. The present invention relates to a valve opening / closing control device provided with a valve driving device for opening or closing a flap type valve of a switching valve.

[Conventional technology]
Conventionally, as a valve driving device that drives a valve of an on-off valve by using a displacement of a diaphragm of a negative pressure actuator, for example, a part of exhaust gas (exhaust gas recirculation gas: EGR gas) flowing out from the engine is A switching valve device (valve opening / closing control device) incorporated in an exhaust gas recirculation device that recirculates to an intake system is known (see, for example, Patent Document 1). As shown in FIG. 10, the housing 102 is connected to the inlet and outlet of a U-turn flow type EGR cooler 101 disposed in the middle of the exhaust gas recirculation pipe of the exhaust gas recirculation device. The two first and second butterfly valves 111 and 112 are opened and closed via the two first and second butterfly valves 111 and 112 accommodated in the housing 102 so as to be freely opened and closed, and the link mechanism 113. And a negative pressure actuated actuator 107.

  Inside the housing 102, a cooler side communication path (cooler inlet side communication path 103 and cooler outlet side communication path 104) for recirculating EGR gas to the intake passage of the engine via the EGR cooler 101, A bypass side communication path (bypass flow path) 105 for recirculating the EGR gas to the engine intake path by bypassing the EGR cooler 101 is disposed in parallel. The exhaust gas recirculation pipe 120 connected to the exhaust gas inlet 121 of the cooler inlet side communication passage 103 of the housing 102 and the exhaust gas inlet 122 of the bypass side communication passage 105 is upstream of the housing 102 in the EGR gas flow direction. It has a branch pipe that branches off. Further, the exhaust gas recirculation pipe 130 connected to the exhaust gas outlet 131 of the cooler outlet side communication passage 104 of the housing 102 and the exhaust gas outlet 132 of the bypass side communication passage 105 is located downstream of the housing 102 in the EGR gas flow direction. It has a merge pipe that merges.

[Conventional technical problems]
However, in the switching valve device of the conventional exhaust gas recirculation device, when the first butterfly valve 111 is disposed in the cooler fully open position and the second butterfly valve 112 is disposed in the bypass fully closed position, the housing 102 Because the high temperature EGR gas leaks from the gap between the bypass wall surface of the bypass side communication passage 105 and the second butterfly valve 112, the temperature of the low temperature EGR gas cooled by passing through the EGR cooler 101 increases. There has been a problem that pollutants (emissions of NOx and the like) in the exhaust gas discharged from the engine cannot be effectively reduced. In order to solve this problem, it is necessary to increase the size of the EGR cooler 101 and improve the cooling performance of the EGR gas. However, if this method is adopted, the mountability to a vehicle such as an automobile is deteriorated. Problems arise.

[Prior art]
Therefore, the inventor of the present application aims to reduce the amount of valve leakage at the bypass fully closed position of the first butterfly valve 111 and to prevent the EGR cooler 101 from being enlarged and mounted. (Application on November 11, 2005: Comparative Example 1) was filed. As shown in FIGS. 11 and 12, this is because the inside of the housing 4 of the switching valve device 3 coupled to the inlet and outlet of the U-turn flow type EGR cooler 2 and the inlet of the EGR cooler 2. The cooler inlet side communication path 201 that communicates, the cooler outlet side communication path 202 that communicates with the outlet portion of the EGR cooler 2, and the bypass that connects the cooler inlet side communication path 201 and the cooler outlet side communication path 202 by short-circuiting each other. A flow path 203 is formed. As a valve body of a two-position three-way switching valve that opens and closes the bypass passage 203, a flat flap valve 5 that is seated on the first valve seat 31 of the housing 4 and closes the bypass passage 203 is adopted. Yes.

  The bypass fully closed position of the flap type valve 5 of the two-position / three-way switching valve is disposed between the cooler inlet side communication path 201 and the cooler outlet side communication path 202, so that When the seal surface is seated on the first valve seat 31 and the bypass passage 203 is closed (when the bypass is fully closed), the pressure loss of the EGR gas flow passing through the inside of the EGR cooler 2 causes the flap type valve 5 to A pressure difference applied to the surface (differential pressure between the cooler inlet side communication passage 201 and the cooler outlet side communication passage 202) acts in a direction to press the seal surface on the back surface side of the flap type valve 5 against the first valve seat 31. . Thereby, the amount of valve leakage at the bypass fully closed position of the flap type valve 5 can be reduced, and the enlargement of the EGR cooler 2 and the deterioration of the mountability can be prevented.

[Defects of prior technology]
This comparative example 1 has a diaphragm that is displaced according to a pressure difference between a negative pressure chamber that communicates with a negative pressure source and an atmospheric pressure chamber that communicates with the atmosphere, and two positions and three directions are utilized by using the displacement of the diaphragm. A negative pressure actuated actuator 9 that drives the flap type valve 5 of the switching valve to two positions of a valve fully closed position and a cooler fully closed position is employed. As in the first comparative example, when the flap type valve 5 is fully closed by the bypass, the flap type is utilized by utilizing the pressure difference between the cooler inlet side communication path 201 and the cooler outlet side communication path 202 (the differential pressure across the flap type valve 5). In the structure in which the seal surface on the back surface side of the valve 5 is in close contact with the first valve seat 31, the required operating axial force of the negative pressure actuated actuator 9 increases in order to drive the flap valve 5 to open smoothly. When the required operating axial force increases in this way, it is necessary to increase the diameter of the diaphragm. However, this increases the size of the negative pressure operating actuator 9 and causes a problem that mountability deteriorates.

Here, the negative pressure supply amount introduced from the negative pressure source (for example, vacuum pump) to the negative pressure chamber of the negative pressure actuated actuator 9 tends to decrease in accordance with the engine system and high altitude specifications. However, a design that can reliably drive the flap type valve 5 of the two-position / three-way switching valve to the two positions of the valve fully closed position and the cooler fully closed position is required. In order to satisfy this requirement, it is necessary to increase the diameter of the diaphragm, but this causes a problem that the physique of the negative pressure actuated actuator 9 becomes large and mountability deteriorates.
European Patent No. 0987427 (pages 2-8, FIG. 1)

  An object of the present invention is to provide a valve opening / closing control device capable of smoothly driving a valve by reducing an operating axial force necessary for driving the valve. It is another object of the present invention to provide a valve opening / closing control device that can prevent the size of the actuator from increasing in size and improve the mountability.

  According to the first aspect of the present invention, the valve peripheral portion located on the outer peripheral side of the valve seal surface is bent to the seal surface side to provide the valve (the entire valve periphery, the entire circumferential direction of the valve peripheral portion, the valve peripheral portion Valve opening operation that opens the flow path hole by separating the valve from the opening peripheral edge of the flow path hole by the actuator by providing a flap part in the circumferential direction partially (only downstream in the flow direction of the fluid in the valve) Occasionally, the flow of fluid in the fluid flow path of the housing has a flow velocity difference in the flow on the front and back surfaces of the valve as compared to the flat front and back surfaces of the valve. In particular, since the valve peripheral edge of the valve is bent to the seal surface (back surface) side, a fluid with a high flow velocity is generated on the valve surface (opposite side to the seal surface side), and the valve back surface (seal surface) A fluid flow with a low flow velocity occurs on the side). As a result, a pressure difference is generated between the front and back surfaces of the valve, so that lift (operation assist force) can be obtained in the direction in which the valve is separated from the peripheral edge of the opening of the flow path hole, that is, in the valve operation direction.

  Therefore, even if the required operating axial force of the actuator is increased by improving the sealing performance of the valve with respect to the peripheral edge of the opening of the flow path hole, the valve is driven by the lift force (operation assist force) generated in the valve operating direction. Since the operating axial force required to do this can be reduced, the valve can be driven smoothly. Thereby, since the enlargement of the physique of an actuator can be prevented, the enlargement of the physique of the whole apparatus containing an actuator can be prevented. As a result, it is easy to secure a mounting space for the entire apparatus including the actuator, and thus the mounting performance of the entire apparatus including the actuator can be improved.

  According to the second aspect of the present invention, the flow path hole is formed in a direction substantially perpendicular to the flow direction of the fluid flowing inside the fluid flow path, so that the valve is seated on the opening peripheral edge of the flow path hole. Since the seal surface of is located substantially parallel to the flow direction of the fluid flowing inside the fluid flow path, the flow velocity difference of the fluid flowing on the front and back surfaces of the valve is increased, and the pressure difference generated on the front and back surfaces of the valve is increased be able to. That is, the lift force (operation assist force) generated in the valve operation direction can be increased.

  According to the invention of claim 3, when the sealing surface of the valve is seated on the peripheral edge of the opening of the flow path hole and the flow path hole is closed (sealed), the periphery of the open peripheral edge of the flow path hole Since the valve peripheral portion is bent so that the flap portion provided in the valve enters the inside of the annular space provided so as to surround the fluid, the fluid is separated from the flow path wall surface of the housing when the valve is opened by the actuator. It is difficult to flow on the back of the flap part of the valve. As a result, immediately after the valve opening operation of the valve is started by the actuator, a flow with a low flow velocity can be made to flow on the back surface of the valve, and lift (operation assist force) can be generated in the valve operation direction. The valve can be driven immediately by the axial force. Therefore, an actuator with excellent valve opening response can be configured.

According to the invention described in claim 4, as an actuator having a diaphragm that is displaced according to the pressure difference between the two first and second pressure chambers, a negative pressure lower than the atmospheric pressure from the negative pressure source to the first pressure chamber. Is introduced, a pressure difference is generated between the first pressure chamber communicating with the negative pressure source and the second pressure chamber communicating with the atmosphere, and the diaphragm is displaced according to the pressure difference, so that the valve A negative pressure actuated actuator is employed that generates an actuating axial force (driving force in the axial direction) that separates the sealing surface from the peripheral edge of the opening of the flow path hole.
Accordingly, if the negative pressure supply amount introduced from the negative pressure source into the first pressure chamber is the same as that in Comparative Example 1 (see FIGS. 11 and 12), the diaphragm diameter can be reduced. Thereby, since the physique of a negative pressure actuated actuator can be reduced in size, the physique of the whole apparatus containing a negative pressure actuated actuator can be reduced in size. As a result, it is easy to secure the mounting space for the entire apparatus including the negative pressure actuated actuator, and therefore the mountability of the entire apparatus including the negative pressure actuated actuator can be improved.

  In addition, since the required operating axial force of the negative pressure actuated actuator is reduced, even if the negative pressure supply amount of the negative pressure actuated actuator into the first pressure chamber is small, the valve seal surface is allowed to flow. It can be easily detached from the opening periphery of the passage hole. Thereby, the negative pressure consumption of a negative pressure source is securable. Here, if the negative pressure source is an electric negative pressure pump (for example, an electric vacuum pump) that generates negative pressure using electric energy, the valve can be driven with a small amount of power consumption.

  According to the fifth aspect of the present invention, the spring provided in the negative pressure actuated actuator applies a spring load to the diaphragm in a direction in which the seal surface of the valve is pressed against the peripheral edge of the opening of the flow path hole. . Thereby, valve leakage when the valve is fully closed can be prevented. According to the invention described in claim 6, when the diaphragm is displaced according to the pressure difference between the first and second pressure chambers of the negative pressure actuated actuator, the rod is displaced in the axial direction in conjunction with the diaphragm. . When the displacement in the axial direction of the rod is transmitted to the valve, the valve is driven. That is, the valve is released from the peripheral edge of the opening of the flow path hole and the flow path hole is opened.

  According to the seventh aspect of the present invention, when the diaphragm is displaced according to the pressure difference between the first and second pressure chambers of the negative pressure actuated actuator, the rod linearly moves in the axial direction in conjunction with the diaphragm. . Then, when the displacement in the axial direction of the rod is transmitted to the valve shaft via the motion direction conversion mechanism that converts the linear motion in the axial direction of the rod into the rotational motion of the valve shaft, the valve shaft rotates by a predetermined rotation angle. To do. Thereby, the valve is driven by the flap-type valve rotating around the axis of the valve shaft. That is, the valve is released from the peripheral edge of the opening of the flow path hole and the flow path hole is opened. According to the eighth aspect of the present invention, the valve is housed in the inlet portion of the exhaust gas cooler for cooling the exhaust gas flowing out from the internal combustion engine and recirculated to the intake system of the internal combustion engine so as to be opened and closed. The housing is joined. The valve is disposed upstream of the exhaust gas cooler in the exhaust gas flow direction.

  According to the ninth aspect of the present invention, when the valve is seated on the opening peripheral edge of the flow path hole and closes the flow path hole, the exhaust gas flowing into the housing passes through the exhaust gas cooler. Recirculated to the intake system of the internal combustion engine. In addition, when the valve is separated from the opening peripheral edge of the flow path hole to open the flow path hole, the exhaust gas flowing into the housing is recirculated to the intake system of the internal combustion engine, bypassing the exhaust gas cooler. The According to the invention described in claim 10, the valve constitutes a valve body of an on-off valve that opens and closes at least the bypass side communication path. According to the invention described in claim 11, the valve constitutes a valve body of a switching valve that switches between the cooler side communication path and the bypass side communication path.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention is to seal the valve peripheral portion located on the outer peripheral side of the valve sealing surface for the purpose of smoothly driving the valve without increasing the diaphragm diameter of the actuator. It was realized by reducing the operating axial force required to drive the valve by bending the surface side and providing a flap.

[Configuration of Example 1]
FIGS. 1 to 9 show Embodiment 1 of the present invention, FIG. 2 is a diagram showing the overall configuration of an exhaust gas recirculation device, and FIGS. 3 and 4 show the overall structure of a valve opening / closing control device. FIG. 5 is a view showing a negative pressure actuated actuator.

  As shown in FIG. 2, the EGR cooler module 1 of the present embodiment is an exhaust gas cooling device that cools exhaust gas by using an EGR cooler 2 as an exhaust gas cooler, for example, an internal combustion engine such as a diesel engine ( The engine is incorporated in an exhaust gas recirculation device that guides and recirculates part of the exhaust gas flowing out from the combustion chamber of E) to the intake system. This exhaust gas recirculation device is connected to an exhaust pipe (hereinafter referred to as engine exhaust pipe) 14 of engine E, and a part of exhaust gas flowing out from the combustion chamber of engine E (exhaust recirculation gas: hereinafter referred to as EGR gas) The exhaust gas recirculation pipes 16 and 17 for recirculation in the intake pipe (hereinafter referred to as the engine intake pipe) 15 of the engine E, and the exhaust gas formed in these exhaust gas recirculation pipes 16 and 17 An exhaust gas recirculation amount control valve (hereinafter referred to as an EGR control valve) 19 that continuously or stepwise adjusts the recirculation amount (EGR amount) of the EGR gas passing through the recirculation path is provided.

  Here, an exhaust passage through which exhaust gas flowing out from the combustion chamber of the engine E flows is formed inside the engine exhaust pipe 14. An intake passage is formed inside the engine intake pipe 15 through which intake air filtered by the air cleaner 20 and drawn into the combustion chamber of the engine E flows. Further, the EGR cooler module 1 is directly coupled in series between the exhaust gas recirculation pipes 16 and 17. The exhaust gas recirculation pipe 16 is connected to the exhaust manifold of the engine exhaust pipe 14. Further, the exhaust gas recirculation pipe 17 is connected to an intake manifold or a surge tank of the engine intake pipe 15. Further, the engine E is provided with an engine cooling water circuit (cooling water circulation path) for circulating and supplying engine cooling water to the EGR cooler module 1.

  The engine cooling water circuit includes a cooling water pipe 22 for circulating and supplying engine cooling water from a water jacket (not shown) of the engine E to a cooling water inlet pipe (hot water pipe) 21 of the EGR cooler module 1, and an EGR cooler module. A cooling water pipe 24 for circulating and supplying (returning) engine cooling water from a cooling water outlet pipe (hot water pipe) 23 to a water jacket of the engine E through a radiator (not shown), and an engine cooling water circuit A water pump (not shown) for generating a circulating flow of engine cooling water. In this embodiment, the engine coolant in the predetermined temperature range (for example, 75 to 80 ° C.) is returned to the water jacket of the engine E by exchanging heat between the engine coolant and the outdoor air (outside air) by the radiator. It is configured.

  The EGR cooler module 1 of this embodiment includes a U-turn flow type EGR cooler 2 that heat-exchanges high-temperature EGR gas with engine cooling water to cool the EGR gas, and is airtight at an inlet portion and an outlet portion of the EGR cooler 2. Is integrated with a valve opening / closing control device (hereinafter referred to as a switching valve device) 3, and part of the exhaust gas recirculation pipes 16 and 17 of the exhaust gas recirculation device and the cooling water piping of the engine cooling water circuit 22 and 24 are part of the configuration. Here, the switching valve device 3 includes a housing 4 in which a cooler-side communication path and a bypass-side communication path are formed, and is accommodated in the housing 4 so as to be freely opened and closed, and a bypass fully closed position and a cooler fully closed position. And a two-position three-way switching valve driven in two positions. The housing 4 has a block 13 in which first and second communication holes 11 and 12 are formed.

  The EGR cooler 2 cools the EGR gas below a desired exhaust temperature by exchanging heat between the high-temperature EGR gas introduced from the housing 4 of the switching valve device 3 and the low-temperature engine cooling water flowing from the cooling water pipe 22. It is a water-cooled exhaust gas cooler. The EGR cooler 2 accommodates a plurality of heat exchange tubes (not shown) inside, and has a cooling water passage (not shown) through which engine cooling water circulates around these heat exchange tubes. Yes. Inside the EGR cooler 2, a partition wall 25 is provided that partitions a first exhaust gas flow path group into which the EGR gas flows from the housing 4 and a second exhaust gas flow path group from which the EGR gas flows into the housing 4. It has been.

  Here, the engine cooling water that has flowed from the cooling water pipe 22 into the hot water pipe 21 connected to the housing 4 of the switching valve device 3 is a cooling water passage (for example, around the shaft 6) formed inside the housing 4. (Not shown) to the outlet of the cooling water passage. Then, the engine cooling water is led to the cooling water pipe 24 from the hot water pipe 23 provided in the housing 4 of the switching valve device 3. Each of the plurality of heat exchange tubes is, for example, a U-shaped tube so that EGR gas flows in a U-shape from the inlet of the EGR cooler 2 toward the outlet.

  The housing 4 is coupled to an inlet portion (EGR gas inlet side) and an outlet portion (EGR gas outlet side) of the EGR cooler 2. The housing 4 is integrally formed in a predetermined shape by a metal material (for example, iron-based casting (cast iron), aluminum casting, aluminum die casting, or the like). Further, as shown in FIGS. 1, 3 and 4, the housing 4 is fastened with a screw or the like to a flange portion (not shown) provided at the downstream end of the exhaust gas recirculation pipe 16 in the EGR gas flow direction. The inlet port side flange portion 26 that is tightened and fixed using a tool, and the flange portion (not shown) provided at the upstream end in the EGR gas flow direction of the exhaust gas recirculation pipe 17 are tightened using a fastener such as a screw. A fixed outlet port side flange portion 27 is provided. Further, the housing 4 is provided with an EGR cooler side flange portion 29 that is fastened and fixed to a flange portion (not shown) provided at an inlet portion and an outlet portion of the EGR cooler 2 using a fastener such as a screw. .

  Here, an annular space 30 is formed in the housing 4 of the present embodiment by denting the flow path wall surface of the block 13 so as to surround the periphery of the opening peripheral edge of the first communication hole 11. Moreover, the housing 4 of the present embodiment has two first and second valve seats 31 and 32 on which a valve body (a flap type valve 5) of a two-position / three-way switching valve can be seated. The first and second valve seats 31 and 32 are first and second cylindrical bodies integrally formed in a cylindrical shape by a metal material having excellent heat resistance and corrosion resistance (for example, stainless steel such as SUS303). (First and second cylindrical bodies). After the first and second valve seats 31 and 32 are manufactured separately from the housing 4, the first and second valve seats 31 and 32 are press-fitted into the hole wall surfaces of the first and second communication holes 11 and 12 provided in the block 13.

  An annular first end surface of the first valve seat 31 on the one axial side (upstream side in the EGR gas flow direction) can be seated on the first seal surface 91 on the back side of the flap valve 5. One valve seat portion 33 is provided. The first valve seat portion 33 corresponds to the opening peripheral portion of the flow path hole (first communication hole 11) of the present invention, and is used as a restricting portion that restricts the rotational operation range of the flap valve 5. . Accordingly, when the first seal surface 91 on the back surface side of the flap type valve 5 is seated on the first valve seat portion 33 of the first valve seat 31, one side in the further rotational direction of the flap type valve 5 (first side) The rotational movement to the side that closes the communication hole 11) is restricted. The first valve seat portion 33 of the first valve seat 31 has a seat contact area with the first seal surface 91 on the back surface side of the flap type valve 5 to reduce the contact surface of the flap type valve 5 and the first valve seat. You may provide the annular | circular shaped convex part for improving the sealing surface pressure with the close_contact | adherence surface of 31. FIG. The annular space 30 is circumferentially arranged around the first valve seat portion 33 of the first valve seat 31 between the outer periphery of the first valve seat portion 33 of the first valve seat 31 and the flow path wall surface of the block 13. It is formed so as to surround.

  In addition, an annular second end surface on the one side in the axial direction of the second valve seat 32 (upstream side in the EGR gas flow direction) on which the second seal surface 92 on the surface side of the flap type valve 5 can be seated. Two valve seats 34 are provided. The second valve seat portion 34 corresponds to the opening peripheral portion of the flow path hole (second communication hole 12), and is used as a restricting portion that restricts the rotational operation range of the flap valve 5. Thus, when the second seal surface 92 on the front surface side of the flap type valve 5 is seated on the second valve seat portion 34 of the second valve seat 32, the flap type valve 5 on the other side in the further rotational direction (second side). The rotational movement to the side that closes the communication hole 12 is restricted.

  At the upstream end of the housing 4 in the exhaust gas flow direction, an inlet port (exhaust gas inlet and fluid inlet of the housing 4) 35 is opened, and at the downstream end of the housing 4 in the exhaust gas flow direction, An outlet port (exhaust gas outlet, fluid outlet of the housing 4) 45 is opened. The inlet port 35 is connected to the downstream opening end of the exhaust gas recirculation pipe 16, and the outlet port 45 is connected to the upstream opening end of the exhaust gas recirculation pipe 17.

  In addition, two cooler-side and bypass-side communication paths are formed for one inlet port 35 inside the housing 4, that is, between the outer wall portion of the housing 4 and the block 13. The cooler-side communication passage has a cooler inlet-side communication passage that communicates with the inlet portion of the EGR cooler 2 and a cooler outlet-side communication passage that communicates with the outlet portion of the EGR cooler 2, and EGR gas that has flowed into the interior from the inlet port 35 Is a fluid flow path (exhaust gas flow path) for recirculating EGR gas to the intake system of the engine E via the EGR cooler 2.

  The cooler inlet side communication passage extends from the inlet port 35 toward the inlet portion of the EGR cooler 2 and extends straight in a direction perpendicular to the axial direction of the bypass side passage hole 42 and the bypass passage 43. The exhaust gas passage 36, the cooler side passage hole 37, and the cooler inlet side communication port 39. The cooler outlet side communication passage is an L-shaped channel bent at a substantially right angle (for example, 90 °) in the middle from the outlet portion of the EGR cooler 2 toward the outlet port 45, and includes a cooler outlet side communication port 40, The exhaust gas passages 41 and 44 are configured. Here, the cooler side flow path hole 37 is formed inside the second valve seat 32 to form a second flow path hole. The cooler inlet side communication port 39 communicates with the inlet side end portions of the plurality of heat exchange tubes of the EGR cooler 2. The cooler outlet side communication port 40 communicates with the outlet side end portions of the plurality of heat exchange tubes of the EGR cooler 2.

  The bypass-side communication path has a bypass-side channel hole 42 and a bypass channel 43 that communicate with each other by short-circuiting (cooling) the cooler inlet-side communication path and the cooler outlet-side communication path, and flows into the interior from the inlet port 35. This is a fluid flow path (exhaust gas flow path) that recirculates EGR gas to the intake system of the engine E by bypassing EGR gas from the EGR cooler 2. The bypass side communication path is an L-shaped channel bent at a substantially right angle (for example, 90 °) in the middle from the inlet port 35 toward the outlet port 45, and includes an exhaust gas channel 36, a bypass side channel hole. 42, a bypass channel 43 and an exhaust gas channel 44. Further, the bypass side communication path constitutes a second linear flow path extending straight from the exhaust gas flow path 36 toward the outlet port 45 in the axial direction of the bypass side flow path hole 42 and the bypass flow path 43. Here, the bypass-side passage hole 42 is formed inside the first valve seat 31 to form a first passage hole, and branches in the middle of the cooler inlet-side communication passage (exhaust gas passage, fluid passage). A flow path hole is formed.

  Here, a block 13 is integrally formed in the housing 4 so as to partition the cooler inlet side communication passage and the cooler outlet side communication passage in an airtight manner. A shaft housing hole 46 extending in the valve axial direction (axial direction of the shaft 6) is provided inside the block 13, and a two-position / three-way switching valve is provided via a bearing component (not shown) such as a bushing. A cylindrical valve bearing portion is provided to support the shaft 6 slidably in the rotational direction. For this reason, the shaft 6 of the two-position / three-way switching valve is rotatably accommodated in the block 13 by a valve bearing provided in the shaft accommodation hole 46.

  The outer wall portion of the housing 4 located on one end side in the axial direction of the block 13 is open at one end side in the axial direction of the shaft receiving hole 46 of the valve bearing portion. A plug 47 for hermetically closing the opening of the shaft housing hole 46 is hermetically press-fitted and fixed to the housing 4. Further, hot water pipes 21 and 23 are press-fitted and fixed in a liquid-tight manner at the inlet and outlet of the cooling water passage of the housing 4. In addition, a bracket 49 for attaching a negative pressure actuated actuator 9 to be described later is fastened and fixed to the housing 4 using a fastener such as a screw 50.

  Further, between the inner periphery of the shaft housing hole 46 of the block 13 and the outer periphery of the shaft 6 of the two-position / three-way switching valve, there is a seal part (not shown) such as a gas seal in addition to a bearing part such as a bushing. It is installed. Further, the gas seal is integrally formed in a cylindrical shape by a rubber-based elastic body, and in the EGR gas in the gap between the valve bearing portion provided in the shaft housing hole 46 of the block 13 and the shaft 6. It is a sealing part such as a rubber seal that prevents foreign matter from entering.

  The block 13 surrounds the shaft 6 of the two-position / three-way switching valve in the circumferential direction so that the high-temperature EGR gas and the low-temperature EGR gas do not directly hit the shaft 6 of the two-position / three-way switching valve. It is arranged. As a result, the block 13 protects the shaft 6 of the two-position / three-way switching valve, the valve bearing that supports the shaft 6, and the gas seal installed on the shaft 6 from the heat of the high-temperature EGR gas. And the function of protecting the shaft 6 of the two-position / three-way switching valve and the valve bearing portion against an adhesive substance (for example, viscous carbon) contained in the low-temperature EGR gas.

  The two-position / three-way switching valve of the switching valve device 3 is housed in the housing 4 (exhaust gas passage 36) so as to be freely openable / closable (rotatable). A folding flap valve 5 that selectively opens and closes, a cylindrical shaft (valve shaft) 6 that is rotatably supported (supported) by a valve bearing portion of a block 13 of the housing 4, a flap valve 5, A valve lever 7 having a V-shaped cross section for connecting the shaft 6 is formed.

  Here, the valve drive device for driving the valve body (flap type valve 5) of the two-position / three-way switching valve to the two positions of the bypass fully closed position and the cooler fully closed position using the displacement of the thin film diaphragm 8 is as follows. As shown in FIGS. 3 to 5, an electric vacuum pump (not shown) as a negative pressure source that is rotationally driven by the driving force (motor torque) of the electric motor, and an air suction port of the electric vacuum pump An electromagnetic or electric negative pressure control valve (not shown) arranged in the middle of the communicating air flow path pipe, and a negative pressure lower than atmospheric pressure from the electric vacuum pump via this negative pressure control valve Is provided with a negative pressure actuated actuator 9 that generates an actuating axial force in the axial direction.

  The negative pressure actuated actuator 9 includes a rod 51 that reciprocates (displaces) in the axial direction in conjunction with the diaphragm 8, a cylindrical holder 53 in which an air opening hole 52 that extends in the axial direction is formed, and the holder A diaphragm seat 54 disposed at the upper end of the figure 53, and two casings 56 and 57 for accommodating the diaphragm 8 and the coil spring 55 in an elastically deformable manner are provided. The diaphragm 8 is a rubber-based elastic body, and is folded between the outer peripheral edge portions of the casing 57 in a U-shape while being sandwiched between the flange portions of the two casings 56 and 57, so that the outer peripheral edge of the diaphragm 8. The portion is held and fixed between the flange portions of the two casings 56 and 57.

  Here, an internal space (diaphragm chamber) surrounded by the two casings 56 and 57 is hermetically partitioned into two first and second pressure chambers 61 and 62 by the diaphragm 8. The first pressure chamber 61 constitutes a negative pressure chamber communicating with the air suction port of the electric vacuum pump via a negative pressure control valve. The second pressure chamber 62 constitutes an atmospheric pressure chamber communicating with the atmosphere via the atmosphere opening hole 52. The rod 51 is bent in an L-shape at one end side in the axial direction, and the tip of the L-shaped portion is engaged with a fitting hole on the input side of the link plate 63. Further, the other end portion in the axial direction of the rod 51 (the upper end portion shown in FIG. 5) is disposed so as to sandwich the diaphragm 8 in a state of being fitted in a hole provided in the central portion of the diaphragm 8. It is connected to the diaphragm 8 through the plates 64 and 65. Here, the link plate 63 constitutes a motion direction conversion mechanism for converting the linear motion of the rod 51 in the axial direction into the rotational motion of the shaft 6, and constitutes a link mechanism together with the shaft 6 and the rod 51. Further, the axial end portion of the shaft 6 that protrudes to the outside from the plug 47 is fixed to the fitting hole on the output side of the link plate 63.

  The holder 53 of the negative pressure actuated actuator 9 is fixed to the shelf-like seat portion of the bracket 49 and holds the negative pressure actuated actuator 9. The coil spring 55 is spring loaded in the direction in which the flap type valve 5 is pressed against the diaphragm 8 against the first valve seat portion 33 of the first valve seat 31 (the valve closing direction, the bypass side passage hole 42 closing side). Spring load applying means for applying (biasing force). One end in the axial direction of the coil spring 55 is held by a spring seat 66 positioned on the diaphragm side, and the other end in the axial direction of the coil spring 55 is on the ceiling of the casing 56 positioned on the opposite side to the diaphragm side. Held on the wall. The casing 56 is connected to a negative pressure introduction pipe 67 for introducing a negative pressure from the electric vacuum pump into the first pressure chamber 61 via a negative pressure control valve.

  The upper end of the diaphragm seat 54 is illustrated by the diaphragm load due to the spring load (biasing force) of the coil spring 55 when the negative pressure supply from the electric vacuum pump to the negative pressure actuated actuator 9 is stopped (negative pressure introduction cut). It is used as a restricting portion (stopper) that restricts the displacement amount (default position) of the diaphragm 8 when displaced downward. Thereby, when the back surface side of the diaphragm 8 contacts the diaphragm seat portion 54, further displacement of the diaphragm 8 is restricted. That is, the position of the diaphragm 8 is the default position.

  Here, 69 is a plug (stopper) for airtightly closing the opening portion opened by the ceiling wall of the casing 56 and restraining the stroke of the diaphragm 8. The lower end of the plug 69 in the axial direction has a diaphragm 8 in accordance with the pressure difference between the two first and second pressure chambers 61 and 62 when negative pressure is supplied from the electric vacuum pump to the negative pressure actuated actuator 9. It is used as a restricting portion (stopper) that restricts the displacement amount (full lift position, full lift amount) of the diaphragm 8 when displaced upward in the figure. Thereby, when the surface side of the diaphragm 8 contacts the plug 69, the further displacement of the diaphragm 8 is restricted. That is, the position of the diaphragm 8 is the full lift position.

  The negative pressure actuated actuator 9 overcomes the combined force of the spring load (SPG load) of the coil spring 55 and the external force (engine external force: vibration, pressure) received from the engine E when the flap valve 5 is opened. 5 is designed to open. In other words, the operating axial force of the negative pressure actuated actuator 9 using the diaphragm 8 is determined by “diaphragm diameter × applied negative pressure”, and this “diaphragm diameter × applied negative pressure” is determined by “engine external force (vibration, pressure) + It is designed to exceed the “spring load (SPG load)”. The negative pressure actuated actuator 9 designed in this way utilizes the pressure difference between the two first and second pressure chambers 61 and 62 to cause the diaphragm 8 to resist itself against the spring load of the coil spring 55. By displacing (upward in the drawing) in the plate thickness direction (upward and downward in the drawing in FIG. 5), the rod 51 linked to the diaphragm 8 is displaced upward in the axial direction in the drawing. When the axial upward displacement of the rod 51 is transmitted to the shaft 6 via the link plate 63, the shaft 6 rotates by a predetermined rotation angle (operation angle θ: for example 40 to 50 °). . Accordingly, the two-position three-way switching valve is driven to two positions, that is, a bypass fully closed position of the flap type valve 5 and a cooler fully closed position of the flap type valve 5.

  Here, the electric vacuum pump and the negative pressure control valve are configured to be energized and controlled by an engine control unit (hereinafter referred to as ECU) 10. The negative pressure control valve is configured to switch the amount of negative pressure supplied to the inside of the first pressure chamber 61. Here, the ECU 10 is configured to include functions of a CPU that performs control processing and arithmetic processing, a storage device (memory such as ROM and RAM) that stores various programs and data, an input circuit, an output circuit, and the like. A microcomputer having a structure is provided. The ECU 10 is configured to electronically control the valve opening degree of the flap valve 5 based on a control program and a map 70 stored in the memory when an ignition switch (not shown) is turned on (IG / ON). Yes. The ECU 10 is configured to forcibly terminate the above-described control based on the control program stored in the memory when the ignition switch is turned off (IG / OFF).

  The sensor signals from the various sensors are A / D converted by an A / D converter and then input to a microcomputer built in the ECU 10. The microcomputer includes a crank angle sensor, an accelerator opening sensor, a coolant temperature sensor, an air flow meter that indirectly detects the amount of EGR flowing through the exhaust gas recirculation pipes 16 and 17, and an intake into the combustion chamber of the engine E. The intake air temperature sensor (intake air temperature detection means) 71 for detecting the temperature of intake air to be discharged (intake air temperature detection means) and the temperature of EGR gas that flows out of the EGR cooler module 1 and recirculates to the engine intake pipe 15 are detected. An exhaust temperature sensor (exhaust temperature detection means) 72 and the like are connected.

  The flap type valve 5 of the two-position / three-way switching valve of the present embodiment is formed in a predetermined bent shape by a metal material (for example, stainless steel such as SUS304) having excellent heat resistance and corrosion resistance. The flap type valve 5 is formed by placing a flat metal plate on a die and pressing it into a hole of the die with a punch slightly smaller than the outer diameter of the flap type valve 5 to form a bottomed product (for example, deep drawing) Manufactured). As shown in FIGS. 1, 6, and 7, the flap-type valve 5 is seated on and disengaged from the first valve seat 31 of the housing 4 on one end surface in the plate thickness direction. A first sealing surface 91 that closes and opens the hole 42 is provided. The first seal surface 91 corresponds to the seal surface of the present invention, and is provided on the back side opposite to the surface of the flap valve 5. Further, as shown in FIGS. 1, 6, and 8, the flap-type valve 5 is seated on and disengaged from the second valve seat 32 of the housing 4 on the other end surface in the thickness direction of the flap-type valve 5. A second sealing surface 92 that closes and opens the hole 37 is provided. The first and second sealing surfaces 92 of the flap valve 5 are circular flat surfaces.

  The flap-type valve 5 is divided into a bypass fully closed position (default position, operating angle θ = 0 °: see FIG. 7) and a cooler fully closed position (full lift position, operating angle θ = 40-50 °: see FIG. 8). It is configured to be driven to a position. The bypass fully closed position means that when the bypass is fully closed, the first seal surface 91 on the back surface side of the flap type valve 5 is seated (contacted) on the first valve seat 31 to open the cooler side passage hole 37 (fully open). And the valve seat position of the flap-type valve 5 that closes (fully closes) the bypass side passage hole 42. Further, the cooler fully closed position means that when the cooler is fully closed, the second seal surface 92 on the surface side of the flap type valve 5 is seated (contacted) on the second valve seat 32 to close the cooler side passage hole 37 ( This is the valve seat position of the flap type valve 5 that is fully closed) and that opens (fully opens) the bypass side passage hole 42.

  Further, as shown in FIGS. 6 and 7, the flap type valve 5 is an average of EGR gas (fluid) flowing through the exhaust gas flow path (fluid flow path) 36 of the housing 4 when the bypass is fully closed. The axial direction of the flow and the perpendicular direction (the surface direction of the first and second seal surfaces 91 and 92) perpendicular to the axial direction of the flap type valve 5 are arranged substantially in parallel. The flap-type valve 5 bends the valve peripheral portion located on the outer peripheral side (outer diameter side) in the radial direction with respect to the first seal surface 91 to the first seal surface side (lower side in the drawing) by a predetermined inclination angle, An all-around flap portion 93 capable of obtaining a high lift is provided as necessary. Further, in the present embodiment, the valve peripheral portion of the flap type valve 5 is bent so that the entire peripheral flap portion 93 enters the inside of the annular space 30 when the bypass of the flap type valve 5 is fully closed. Therefore, in this embodiment, the entire circumference flap portion 93 is provided on the entire circumference of the valve (entirely in the circumferential direction of the valve peripheral portion of the flap type valve 5) to form the folded flap type valve 5, as shown in FIG. As described above, in the valve opening operation by the negative pressure operation type actuator 9 (when switching from the bypass fully closed position to the cooler fully closed position), the valve opening direction of the flap valve 5 is assisted (valve operating direction). ) Generates lift (operation assist force).

  The shaft 6 of the two-position / three-way switching valve of the present embodiment is integrally formed of a metal material excellent in heat resistance and corrosion resistance (for example, stainless steel such as SUS304). The shaft 6 is supported on the inner periphery of the shaft accommodation hole 46 of the block 13 so as to be slidable in the rotational direction via a bearing part and a seal part. A cylindrical lever fixing portion 94 that holds and fixes the fixed end of the valve lever 7 is fixed to the outer periphery of the shaft 6. One end portion of the shaft 6 in the shaft direction protrudes from the plug 47 to the outside of the housing 4.

  The valve lever 7 is integrally formed in a predetermined shape (for example, a V shape) with a metal material (for example, stainless steel such as SUS304) having excellent heat resistance and corrosion resistance. The valve lever 7 has a fixed end fixed at one end to the outer periphery of the lever fixing portion 94 of the shaft 6 by using a fixing means such as welding, and the other end is a second end on the back side of the flap type valve 5. 1 It has the free end which fixes 91 sealing surfaces (illustration lower end surface).

  The fixed end of the valve lever 7 is formed in an arc shape (or a cylindrical shape) corresponding to the columnar shape of the valve holding portion of the shaft 6, and is formed on a part of the circumferential surface of the outer peripheral surface of the valve holding portion of the shaft 6, for example. It is held and fixed using fixing means such as welding. The free end of the valve lever 7 is formed in a shape corresponding to the hole shape in the central part of the flap type valve 5, and the central part of the first seal surface 91 on the back side of the flap type valve 5 is welded, for example. It is held and fixed using the fixing means. Therefore, the flap type valve 5 selectively opens and closes the cooler-side channel hole 37 and the bypass-side channel hole 42 on the free end side of the valve lever 7 by a rotation operation starting from the fixed end side of the valve lever 7 1. It constitutes a single valve body.

[Operation of Example 1]
Next, the operation of the exhaust gas recirculation device of the present embodiment will be briefly described with reference to FIGS.

  For example, when the engine E such as a diesel engine is started and the intake valve of the intake port formed in the cylinder head of the engine E is opened, the intake air filtered by the air cleaner 20 is changed into the engine intake pipe 15, the throttle body, It is distributed to the intake manifold of each cylinder through the surge tank, and is sucked into the combustion chamber of each cylinder of the engine E. In the engine E, air is compressed until it reaches a temperature higher than the temperature at which the fuel burns, and high pressure fuel is sprayed from the injector there, and combustion is performed.

  Then, the combustion gas burned in the combustion chamber of each cylinder of the engine E is discharged from an exhaust port formed in the cylinder head of the engine E, and is discharged through the exhaust manifold and the engine exhaust pipe 14. Here, when the negative pressure control valve and the electric vacuum pump are not energized, the spring load (biasing force) of the coil spring 55 provided in the casings 56 and 57 of the negative pressure actuated actuator 9 is used. Since the diaphragm 8 is pressed against the diaphragm seat 54, the rod 51 of the negative pressure actuated actuator 9 is positioned below the figure (see FIGS. 3 and 5). In this case, as shown in FIG. 7, the first seal surface 91 on the back surface side of the flap type valve 5 is maintained at the valve seat position where the first valve seat portion 33 of the first valve seat 31 is seated. Accordingly, the valve seat position of the flap type valve 5 is maintained at the bypass fully closed position where the cooler side channel hole 37 is opened (fully opened) and the bypass side channel hole 42 is closed (fully closed).

  Therefore, the high-temperature EGR gas (for example, the exhaust temperature of 450 to 600 ° C.) flowing into the housing 4 (exhaust gas flow path 36) from the exhaust gas recirculation pipe 16 via the inlet port 35 is shown in FIG. As described above, it flows straight through the cooler side passage hole 37 and the cooler inlet side communication port 39, and flows into the EGR cooler 2 from the cooler inlet side communication port 39. The high-temperature EGR gas that has flowed into the EGR cooler 2 is cooled by exchanging heat with engine cooling water (for example, a cooling water temperature of about 80 to 90 ° C.) when passing through the plurality of heat exchange tubes. (For example, an exhaust temperature of about 100 ° C.). Then, the low-temperature EGR gas flows again into the housing 4 (exhaust gas passage 41) from the cooler outlet side communication port 40, and after the flow direction is bent by about 90 ° in the exhaust gas passage 44, the outlet port 45 And flows out of the housing 4. The low-temperature EGR gas that has flowed out of the housing 4 is recirculated (refluxed) to the engine intake pipe 15 via the exhaust gas recirculation pipe 17.

  On the other hand, the valve seat position of the flap type valve 5 of the switching valve device 3 is set to the cooler fully closed position where the valve seat position of the second valve seat 32 is seated and the cooler side passage hole 37 is closed. When the negative pressure control valve and the electric vacuum pump are energized, positive pressure is generated at the air discharge port of the electric vacuum pump and negative pressure is generated at the air suction port. Since the air in the pressure chamber 61 is sucked, the inside of the first pressure chamber 61 of the negative pressure actuated actuator 9 is in a negative pressure state, and between the second pressure chamber 62 and the first pressure chamber 61 communicating with the atmosphere. A pressure difference is generated.

  As a result, the diaphragm 8 is displaced upward in the drawing in accordance with the pressure difference between the two first and second pressure chambers 61 and 62 against the spring load (biasing force) of the coil spring 55, so that the rod 51 is moved in the axial direction. Move in the direction. The link plate 63 rotates about the axis of the shaft 6 along with the linear movement of the rod 51 in the axial direction, and the shaft 6 fixed to the link plate 63 rotates along with the rotation of the link plate 63. Rotate around. As a result, the flap type valve 5 rotates about the axis of the shaft 6, so that it is separated from the first valve seat portion 33 of the first valve seat 31 and the second valve seat portion 34 of the second valve seat 32. Sit on. Therefore, the valve seat position of the flap type valve 5 is a cooler fully closed position in which the cooler side flow path hole 37 is closed (fully closed) and the bypass side flow path hole 42 and the bypass flow path 43 are opened (fully opened). .

  Therefore, the high-temperature EGR gas that has flowed into the exhaust gas passage 36 of the housing 4 via the inlet port 35 from the exhaust gas recirculation pipe 16 passes through the exhaust gas passage 36 as shown in FIG. Of the second valve seat 32 and the first seal surface 91 on the back surface side of the flap type valve 5 seated on the second valve seat portion 34 of the second valve seat 32. At this time, since the first seal surface 91 on the back surface side of the flap valve 5 is inclined at a predetermined inclination angle (for example, about 40 to 50 °) with respect to the axial direction of the linear flow path, the flap valve 5 The flow direction of the high-temperature EGR gas that has collided with the first seal surface 91 on the back surface side of the rear side is changed to the axial direction of the bypass-side passage hole 42 and the bypass passage 43. The high-temperature EGR gas that has passed through the bypass-side channel hole 42 and the bypass channel 43 flows straight in the axial direction of the bypass-side channel hole 42 and the bypass channel 43, and enters the exhaust gas channel 44 of the housing 4. It flows in and flows out from the outlet port 45 to the outside of the housing 4. The high-temperature EGR gas that has flowed out of the housing 4 is recirculated (refluxed) to the engine intake pipe 15 via the exhaust gas recirculation pipe 17.

  Here, for example, during normal operation, the valve seat position of the flap type valve 5 is set so that the first seal surface 91 on the back side of the flap type valve 5 is seated on the first valve seat portion 33 of the first valve seat 31 and the bypass side flow is established. As shown in FIG. 7, the total flow rate of the EGR gas introduced into the EGR cooler module 1 from the exhaust gas recirculation pipe 16 is set to the bypass fully closed position for closing (fully closing) the passage hole 42 as shown in FIG. When the interior of the cooler 2 is passed through and recirculated (refluxed) to the engine intake pipe 15, the high temperature EGR gas is sufficiently cooled inside the EGR cooler 2. As a result, the low temperature EGR gas having a low temperature and a low density is mixed with the intake air in the intake passage of the engine intake pipe 15, so that the output of the engine E is not reduced and each cylinder of the engine E is reduced. The combustion temperature of the fuel in the combustion chamber decreases, and the generation of pollutants (emissions such as NOx) in the exhaust gas discharged from the engine E can be effectively reduced.

  Further, for example, during cold weather, the valve seat position of the flap type valve 5 is set so that the second seal surface 92 on the surface side of the flap type valve 5 is seated on the second valve seat portion 34 of the second valve seat 32 and the cooler side flow path. As shown in FIG. 8, the total flow rate of the EGR gas introduced into the EGR cooler module 1 from the exhaust gas recirculation pipe 16 is set to the bypass side. If the air is passed through the passage hole 42 and the bypass passage 43 and is recirculated (refluxed) to the engine intake pipe 15, the EGR gas is recirculated with a relatively high temperature. As a result, a sufficient warming effect on the intake air can be obtained, the combustibility of the engine E is improved, and pollutants (emissions such as HC) and white smoke are generated in the exhaust gas discharged from the engine E. Can be prevented.

  In addition, when the temperature of the intake air is lowered by cooling the EGR gas, the NOx emission amount tends to decrease. However, under relatively low engine speed and low load operating conditions, the EGR gas is reduced. Cooling increases HC emissions. Therefore, by controlling the flap valve 5 to an appropriate valve opening (rotation angle, operating angle θ) according to the operating state of the engine E, the temperature of the EGR gas is changed to an optimum temperature. Further, the NOx emission amount and the HC emission amount can be simultaneously reduced.

[Features of Example 1]
As described above, in the switching valve device 3 of the EGR cooler module 1 incorporated in the exhaust gas recirculation device of the present embodiment, the first seal surface 91 on the back surface side of the flap type valve 5 is the first valve seat 31 of the first valve seat 31. 1 Pressure when EGR gas passes through the EGR cooler 2 when the bypass side passage hole 42 is closed (sealed) by sitting on the valve seat 33 (when the bypass of the flap valve 5 is fully closed) Due to the loss, the differential pressure between the first and second seal surfaces 91 and 92 of the flap type valve 5 causes the first seal surface 91 on the back side of the flap type valve 5 to move to the first valve seat portion 33 of the first valve seat 31. It works greatly in the pressing direction to improve the sealing performance of the flap type valve 5 in the bypass fully closed position of the flap type valve 5 and to effectively reduce the valve leakage amount in the bypass fully closed position of the flap type valve 5. Thereby reducing.

  In the case of such a structure of the EGR cooler module 1, the required operating axial force of the negative pressure actuated actuator 9 increases, and the diameter of the diaphragm 8 of the negative pressure actuated actuator 9 needs to be increased. There is a problem that the physique of the actuating actuator 9 becomes large and the mountability deteriorates.

Here, generally, the required operating axial force (Example 1 = α, Comparative Example 1 = β) of the negative pressure operating actuator 9 using the diaphragm 8 is received from the engine E as shown in FIG. The fluid force (Example 1 = α2, Comparative Example 1 = β2) of the flap type valve 5 is added to the resultant force (γ) of the external force (engine external force: vibration, pressure, for example) and the spring load (SPG load) of the coil spring 55. A working axial force greater than the added value is required.
This is expressed by the following equation (1).
[Equation 1]
“Necessary operating axial force for negative pressure actuators”
≥ "Engine external force (vibration, pressure) + SPG load + flap type valve fluid force"
In particular, the fluid force of the flap-type valve 5 is a positive value (the load opposite to the valve operation direction: a so-called load) between the flow direction of the EGR gas (fluid) and the operation direction of the negative pressure actuator 9. Or a negative value (load in the direction of assisting with respect to the valve operating direction: so-called assist force).

In addition, the negative pressure supply amount to the inside of the first pressure chamber 61 of the negative pressure actuated actuator 9 tends to decrease along with the engine system and the high altitude specification. There is a need for a design that can smoothly open the valve without increasing the size of the negative pressure actuator 9.
In this case, the operating axial force of the negative pressure actuated actuator 9 greater than the external force (engine external force) received from the engine E is required, and the operating axial force of the negative pressure actuated actuator 9 is “diaphragm diameter × applied negative Since it is necessary to satisfy the “pressure-spring load of the coil spring 55 (SPG load)”, if the negative pressure supply amount into the first pressure chamber 61 of the negative pressure actuated actuator 9 decreases, the negative pressure actuated type The operating axial force of the actuator 9 is reduced. In order to cover this, it is necessary to enlarge the diameter of the diaphragm 8, but this causes a problem that the physique of the negative pressure actuated actuator 9 becomes large and mountability deteriorates.

  Therefore, for the purpose of preventing the deterioration of the mountability due to the increase in the size of the negative pressure actuated actuator 9, in this embodiment, instead of the flat-plate-shaped flap-type valve 5 of Comparative Example 1, a bent-shaped flap is used. The mold valve 5 is adopted. Specifically, the entire periphery of the flap type valve 5 is provided with an entire periphery flap part 93 for bending the valve peripheral part of the flap type valve 5 to the first seal surface side to obtain a high lift as required. Thus, the flap type valve 5 is bent around the entire circumference.

  Therefore, when the valve opening operation for switching the valve seat position of the flap type valve 5 from the bypass fully closed position to the cooler fully closed position is performed by introducing a negative pressure into the first pressure chamber 61 of the negative pressure operating actuator 9. The EGR gas flow flowing into the exhaust gas flow path 36 from the port 35 has a flow velocity difference in the flow on the front and back surfaces of the valve, as compared with Comparative Example 1 having a flat valve front and back surfaces. In particular, since the valve peripheral portion of the flap type valve 5 is bent toward the first seal surface (back surface), as shown in FIG. 6, the valve surface (second side opposite to the first seal surface side). A flow of EGR gas having a high flow velocity is generated on the seal surface 92), and a flow of EGR gas having a low flow velocity is generated on the back surface (first seal surface side) of the valve. As a result, a pressure difference is generated between the front and back surfaces of the valve. Therefore, as shown in FIGS. 1 and 6, the direction in which the flap type valve 5 is detached from the first valve seat portion 33 of the first valve seat 31, that is, the flap type is used. Lift force can be obtained in the valve opening direction (valve operating direction) of the valve 5. This lift acts as an operation assist force that assists the operation axial force in the valve operation direction.

  That is, the EGR gas flow along the valve surface flows fast, and the EGR gas flow along the valve back surface flows slowly. In particular, since the valve peripheral portion of the flap type valve 5 is bent toward the first seal surface (back surface), the difference in the flow rate of the EGR gas on the front and back surfaces of the valve becomes more remarkable. As shown in FIG. 6, the pressure is low at a portion where the EGR gas flow is fast, and the pressure is high at a portion where the EGR gas flow is slow. Thereby, the pressure on the valve surface side becomes lower than the pressure on the valve back surface side. This pressure difference acts and the flap type valve 5 is pushed up from the back surface of the valve, and valve lift is generated as shown in FIGS. In particular, since the valve peripheral portion of the flap type valve 5 is bent toward the first seal surface (back surface), a high lift is obtained in the valve opening assist direction.

  Therefore, the negative pressure supply amount to the inside of the first pressure chamber 61 of the negative pressure actuated actuator 9 is reduced with the engine system and the high altitude specification, and the pressure difference between the two first and second pressure chambers 61 and 62 is reduced. If the driving force in the axial direction of the rod 51 of the negative pressure actuated actuator 9 using the diaphragm 8 (actuating axial force) decreases, or the sealing performance of the flap valve 5 is improved as in this embodiment. Even if the required operating axial force of the negative pressure operating actuator 9 is increased by this, as shown in FIG. 9, the operating axial force (negative pressure) required for opening the flap valve 5 is opened. Necessary operating axial force of the actuating actuator 9) can be reduced from β to α.

  Here, when the fluid force acting on the folded flap valve 5 of the first embodiment is α2, the resultant force of the engine external force (vibration, pressure) and the SPG load is γ, and the resultant load is α1, The composite load (α1) in Example 1 is (γ + α2). Further, when the fluid force acting on the flat flap valve 5 of the comparative example 1 is β2, the resultant force of the engine external force (vibration, pressure) and the SPG load is γ, and the resultant load is β1, the comparative example The combined load (β1) of 1 is (γ + β2). Therefore, the required operating axial force (α) of the first embodiment can be reduced by the difference in fluid force (β2−α2) than the required operating axial force (β) of the comparative example 1 (see FIG. 9). The flap type valve 5 can be smoothly opened by the negative pressure actuated actuator 9 without increasing the diameter of the diaphragm. Thereby, since the enlargement of the physique of the negative pressure action type actuator 9 can be prevented, the enlargement of the physique of the whole apparatus (EGR cooler module 1) including the negative pressure action type actuator 9 can be prevented. As a result, it becomes easy to secure a space for mounting the EGR cooler module 1 on a vehicle such as an automobile, so that the mountability of the EGR cooler module 1 can be improved.

  Further, in the switching valve device 3 of the present embodiment, the bypass side passage hole 42 is directed to the flow direction of the EGR gas flow that flows through the inside of the cooler inlet side communication passage (fluid passage) including the exhaust gas passage 36. It is formed in a substantially right angle direction. Thus, the EGR gas flow in which the first seal surface 91 on the back surface side of the flap valve 5 seated on the first valve seat portion 31 of the first valve seat 31 flows inside the cooler inlet side communication passage (fluid flow path). Therefore, the difference in the flow velocity of the fluid flowing on the front and back surfaces of the flap type valve 5 is increased, and the pressure difference generated on the front and back surfaces of the flap type valve 5 can be further increased. it can. That is, the lift force (operation assist force) generated in the valve opening operation direction of the flap valve 5 can be increased.

  Further, in the switching valve device 3 of the present embodiment, the flap type valve 5 is arranged so that the entire circumferential flap portion 93 of the flap type valve 5 enters the inside of the annular space 30 when the bypass of the flap type valve 5 is fully closed. When the flap type valve 5 is opened by the negative pressure actuated actuator 9, the EGR gas flow is caused to flow through the wall surface of the flow path of the block 13 and the back surface of the entire circumference flap part 93 of the flap type valve 5. It is difficult to flow into. As a result, negative pressure is introduced into the first pressure chamber 61 of the negative pressure actuated actuator 9 from the electric vacuum pump, and the flap type valve 5 is opened using the operating axial force of the negative pressure actuated actuator 9. Immediately after starting the operation, a flow having a low flow velocity can be caused to flow on the back surface of the flap type valve 5, and lift can be generated in the direction of assisting the valve opening operation of the flap type valve 5. Thus, the flap valve 5 can be driven to open immediately. Therefore, the valve drive device including the negative pressure actuated actuator 9 having excellent valve opening response can be configured.

  Further, if the negative pressure supply amount introduced into the first pressure chamber 61 of the negative pressure actuated actuator 9 from the electric vacuum pump is the same as that in Comparative Example 1 (see FIGS. 11 and 12), the diaphragm diameter is It is possible to reduce the diameter. Thereby, since the physique of the negative pressure actuated actuator 9 can be reduced in size, the entire apparatus including the negative pressure actuated actuator 9 (the switching valve device having the negative pressure actuated actuator 9 externally attached to the outer wall surface of the housing 4). 3, and further, the size of the EGR cooler module 1) in which the EGR cooler 2 and the switching valve device 3 are integrated can be reduced in size. As a result, it becomes easy to secure a space for mounting the EGR cooler module 1 on a vehicle such as an automobile, so that the mountability of the EGR cooler module 1 can be further improved.

  Further, by adopting the bent flap valve 5 that can obtain a high lift during the valve opening operation, the required operating axial force of the negative pressure actuator 9 is reduced. Even if the negative pressure supply amount to the inside of the first pressure chamber 61 is small, the first seal surface 91 on the back surface side of the flap valve 5 can be easily detached from the first valve seat portion 33 of the first valve seat 31. it can. Thereby, since the negative pressure consumption of the electric vacuum pump can be reduced, the flap-type valve 5 can be driven to open with less power consumption (power saving).

  Further, in the negative pressure actuated actuator 9 of the present embodiment, a flap type is provided with respect to the diaphragm 8 in the inner space (diaphragm chamber) surrounded by the two casings 56 and 57, particularly in the first pressure chamber 61. A coil spring 55 that houses a spring load in a direction in which the first seal surface 91 on the back surface side of the valve 5 is pressed against the first valve seat portion 33 of the first valve seat 31 is accommodated. As a result, when the bypass of the flap type valve 5 is fully closed, even if external force (engine external force: vibration, pressure) received from the engine E is transmitted from the valve bearing portion of the block 13 of the housing 4 to the flap type valve 5, Since the first seal surface 91 on the back surface side of the flap type valve 5 is pressed against the first valve seat portion 33 of the first valve seat 31 by the spring load of the coil spring 55, the flap type valve 5 is attached to the first valve seat 31. Occurrence of chattering phenomenon that repeatedly opens and closes the first valve seat portion 33 with a minute lift can be suppressed. Therefore, the amount of valve leakage at the bypass fully closed position of the flap type valve 5 can be effectively reduced, so that the reliability of the switching valve device 3 of the EGR cooler module 1 can be improved.

[Modification]
In this embodiment, as an actuator, a negative pressure lower than the atmospheric pressure is introduced into the first pressure chamber 61, and the second pressure chamber 62 communicating with the atmosphere and the first pressure chamber 61 communicating with the negative pressure source are provided. Although a negative pressure actuated actuator 9 configured to displace the diaphragm 8 using a pressure difference is adopted, a positive pressure higher than atmospheric pressure is introduced into the second pressure chamber 62 as an example of another actuator. Then, the diaphragm 8 may be displaced using a pressure difference between the first pressure chamber 61 communicating with the atmosphere and the second pressure chamber 62 communicating with the pump. As the pump in this case, an air pump is used in which the air sucked from the air suction port is pressurized and discharged from the air discharge port, and the air discharged from the air discharge port is supplied to the second pressure chamber 62. Further, the valve urging of a coil spring 55 or the like that urges the flap type valve 5 of the two-position / three-way switching valve of the switching valve device 3 in the valve closing direction (the side closing the bypass side channel hole 42 and the bypass channel 43). The means may be installed inside the housing 4 of the switching valve device 3.

  Further, in this embodiment, the valve driving device for opening (or closing) the flap type valve 5 of the two-position / three-way switching valve of the switching valve device 3 is provided with a negative pressure control valve and an electric vacuum pump. Although constituted by the negative pressure actuated actuator 9, a valve drive device that opens (or closes) the valve body (valve) of the two-position / three-way switching valve of the switching valve device includes an electric motor and a power transmission mechanism ( For example, an electric actuator including a gear reduction mechanism) or an electromagnetic actuator may be used.

  In the present embodiment, an example in which the flap type valve 5 rotating around the shaft center of the shaft 6 is applied as the valve body of the 2-position 3-way switching valve has been described. Other valves such as a plate type valve and a rotary type valve may be used. Further, the switching valve device is configured to change the valve operating angle between the bypass fully closed position and the cooler fully closed position continuously or stepwise, and the exhaust gas flow rate (low temperature EGR gas amount) passing through the EGR cooler 2 The EGR gas temperature (exhaust gas temperature) recirculated to the intake system of the engine E by adjusting the mixing ratio with the exhaust gas flow rate (high temperature EGR gas amount) passing through the bypass flow path hole 42 and the bypass flow path 43 It may be used as an exhaust gas temperature control valve for controlling. Further, the valve may be a valve body of a channel opening / closing valve that opens and closes only the bypass side channel hole 42.

  In the present embodiment, the example in which the present invention is applied to the two-position three-way switching valve that selectively opens and closes the cooler-side channel hole 37 and the bypass-side channel hole 42 has been described. A plurality of exhaust gas passages having different cooling performances may be provided, and it may be used as a switching valve for switching a plurality of cooler side communication passages respectively communicating with these exhaust gas passages. Further, the valve end face of the two-position / three-way selector valve (the first seal face 91 on the back side of the flap valve 5) is spherical (or arcuate) so that the EGR gas gently changes its flow direction when the cooler is fully closed. ) May be curved.

  In the present embodiment, the present invention is applied to an exhaust gas cooling device (EGR cooler module 1) provided with a U-turn flow type EGR cooler (exhaust gas cooler) 2 in which EGR gas (exhaust gas) flows in a U shape inside. However, the present invention may be applied to an exhaust gas cooling device (EGR cooler module) including an exhaust gas cooler in which EGR gas (exhaust gas) flows in an S shape or an I shape inside. In this case, the outlet tank portion of the exhaust gas cooler and the cooler outlet side communication port 40 of the housing 4 are connected by an exhaust gas pipe having no heat exchange function.

  In the present embodiment, the first valve seat portion 33 on which the first seal surface 91 on the back side of the valve body (flap type valve 5) of the two-position / three-way switching valve is seated is press-fitted into the block 13 of the housing 4. The first valve seat portion on which the valve body (valve) of the two-position / three-way switching valve is seated is provided on the block 13 of the housing 4. You may provide directly in the opening peripheral edge of a communicating hole. In this case, the first valve seat portion is formed integrally with the housing 4. Further, the second valve seat portion 34 on which the second seal surface 92 on the surface side of the valve body (flap type valve 5) of the two-position / three-way switching valve is press-fitted and fitted into the linear flow path of the housing 4. Although provided on the annular end surface of the cylindrical second valve seat 32, the second valve seat portion on which the valve body (valve) of the two-position three-way switching valve is seated is provided in the linear flow path of the housing 4. You may provide directly in the opening peripheral edge of 2 communicating holes. In this case, the second valve seat portion is formed integrally with the housing 4.

  In this embodiment, exhaust gas (EGR gas) flowing out from the engine E is applied as the fluid flowing in the exhaust gas flow path (fluid flow path) 36 of the housing 4, but it flows in the fluid flow path of the housing. As fluid, not only vaporized fuel (evaporative gas) volatilized in the fuel tank, intake air (new intake air) sucked into the cylinder of the engine E, vaporized refrigerant (refrigerant gas) used in the refrigeration cycle, etc. Alternatively, a liquid such as an engine coolant, a liquefied refrigerant used in a refrigeration cycle, or a gas-liquid two-phase refrigerant used in a refrigeration cycle may be used.

  In this embodiment, the flap type valve 5 is housed in a housing 4 in which a cooler side communication path and a bypass side communication path are formed. The flap type valve 5 can be freely opened and closed, but one inlet port (fluid inlet, exhaust gas inlet ) May be housed in a T-shaped branch pipe (housing) having two first and second outlet ports (fluid outlet, exhaust gas outlet). In this case, the linear flow path that extends straight from the inlet port toward the first outlet port forms a fluid flow path, and branches from the middle of the straight flow path to extend toward the second outlet port. The flow path forms a flow path hole. The valve is accommodated in the linear flow path so as to be opened and closed.

  Further, it can be freely opened and closed inside a T-shaped junction pipe (housing) having one outlet port (fluid outlet, exhaust gas outlet) with respect to the two first and second inlet ports (fluid inlet, exhaust gas inlet). A valve may be accommodated. In this case, a straight flow path that extends straight from the first inlet port toward the outlet port forms a fluid flow path, and a merging flow that flows from the second inlet port and joins in the middle of the straight flow path. The path forms a channel hole. The valve is accommodated in the linear flow path so as to be opened and closed.

  In this embodiment, a housing 4 in which a flap-type valve 5 is housed in an openable / closable manner is coupled to an inlet portion of an EGR cooler (heat exchanger) 2 so that the exhaust gas (fluid) flows in a flow direction more than the EGR cooler 2. A flap type valve 5 is arranged on the upstream side. A housing in which the valve is housed in an openable / closable manner is connected to the outlet portion of the heat exchanger so that the fluid flow direction is more downstream than the heat exchanger. A valve may be provided. Moreover, the housing does not necessarily have to be coupled to the inlet or outlet of a heat exchanger such as the EGR cooler 2. Moreover, you may abolish heat exchangers, such as EGR cooler 2. FIG.

  In this embodiment, the valve peripheral portion of the flap type valve 5 is bent at a predetermined inclination angle to the first seal surface side (downward in the figure), and the entire peripheral flap portion 93 is provided on the entire periphery of the flap type valve 5. The valve peripheral portion of the flap type valve 5 is bent toward the first seal surface, and is inclined with respect to the average flow axis of the EGR gas flowing into the exhaust gas passage 36 from the inlet port 35 when the bypass is fully closed. In this way, the flap portion may be partially provided in the flap type valve 5. Further, the size of the flap portion is larger on the downstream side than the upstream side of the EGR gas flowing into the exhaust gas flow path 36 from the inlet port 35, or the inside of the exhaust gas flow path 36 from the inlet port 35. A flap portion may be provided in an arc shape only on the downstream side of the EGR gas flowing into the gas.

(Example 1) which is the explanatory view which showed the valve opening operation of the flap type valve. 1 is a configuration diagram showing the overall configuration of an exhaust gas recirculation device (Example 1). FIG. It is the perspective view which showed the whole structure of the switching valve apparatus (Example 1). It is the perspective view which showed the whole structure of the switching valve apparatus (Example 1). (Example 1) which is sectional drawing which showed the negative pressure action type actuator. (A), (b) is sectional drawing which showed the flap type valve, (c) is the perspective view which showed the flap type valve (Example 1). (Example 1) which is the explanatory view which showed the bypass fully closed position of a flap type valve. It is explanatory drawing which showed the cooler fully closed position of a flap type valve | bulb (Example 1). It is the graph which showed the load and the fluid force with respect to the required operating axial force of a negative-pressure actuated actuator (Example 1). It is sectional drawing which showed the whole structure of the EGR cooler module (conventional technique). It is sectional drawing which showed the whole structure of the switching valve apparatus (comparative example 1). It is explanatory drawing which showed the bypass fully closed position of a flap type valve (comparative example 1).

Explanation of symbols

E engine (internal combustion engine)
1 EGR cooler module (exhaust gas cooling device)
2 EGR cooler (exhaust gas cooler)
3. Switching valve device (valve open / close control device)
4 Housing 5 Flap type valve (2-position 3-way switching valve)
6 Shaft (Valve shaft, valve shaft of 2-position 3-way switching valve)
7 Valve lever (connecting part of 2-position 3-way switching valve)
8 Diaphragm 9 Negative pressure actuated actuator 11 First communication hole (flow path hole)
12 Second communication hole 13 Block (housing)
30 blocks of annular space (annular space of housing)
31 1st valve seat 32 2nd valve seat 33 1st valve seat part of the 1st valve seat (opening peripheral part of a channel hole)
34 Second valve seat portion of second valve seat (opening peripheral edge portion of flow path hole)
35 Housing inlet port (fluid inlet)
36 Exhaust gas flow path (cooler side communication path, bypass side communication path)
37 Cooler side passage hole (cooler side communication passage)
39 Cooler inlet side communication port (cooler side communication passage)
40 Cooler outlet side communication port (cooler side communication passage)
41 Exhaust gas passage (cooler side communication passage)
42 Bypass side passage hole (Bypass side communication passage)
43 Bypass channel (Bypass side communication path)
44 Exhaust gas flow path (cooler side communication path, bypass side communication path)
45 Housing outlet port (fluid outlet)
51 Negative pressure actuated actuator rod 55 Negative pressure actuated actuator coil spring 61 First pressure chamber of negative pressure actuated actuator 62 Second pressure chamber of negative pressure actuated actuator 63 Link plate (motion direction conversion mechanism, link mechanism) )
91 1st sealing surface of flap type valve 92 2nd sealing surface of flap type valve 93 Flap portion (flap portion) of flap type valve

Claims (11)

(A) a housing in which a fluid channel through which a fluid flows and a channel hole that branches or merges in the middle of the fluid channel;
(B) a valve which is accommodated inside the housing so as to be openable and closable, and seats on and disengages from the opening peripheral edge of the flow path hole to close and open the flow path hole;
(C) In a valve opening / closing control device comprising an actuator for driving the valve,
The valve has a seal surface on the back side opposite to the front surface, which is seated on the peripheral edge of the opening of the flow path hole and closes the flow path hole, and is located on the outer peripheral side of the seal surface. A valve opening / closing control device characterized in that a valve peripheral portion is bent toward the seal surface side and a flap portion is provided in the valve. In the valve opening and closing control device according to claim 1,
The valve opening / closing control device according to claim 1, wherein the flow path hole is formed in a direction substantially perpendicular to a flow direction of the fluid flowing in the fluid flow path. In the valve opening and closing control device according to claim 1 or 2,
The housing has an annular space so as to surround the periphery of the opening periphery of the flow path hole, and the valve periphery is bent so that the flap portion enters the inside of the annular space. A valve opening / closing control device. The valve opening / closing control device according to any one of claims 1 to 3, wherein the actuator includes a first pressure chamber communicating with a negative pressure source, a second pressure chamber communicating with the atmosphere, and these Having a diaphragm that is displaced according to the pressure difference between the two first and second pressure chambers;
When a negative pressure lower than the atmospheric pressure is introduced into the first pressure chamber, the negative pressure actuated actuator generates an actuation axial force that separates the seal surface of the valve from the opening peripheral edge of the flow path hole. A valve opening and closing control device characterized by the above. In the valve opening and closing control device according to claim 4,
The negative pressure actuated actuator has a spring that applies a spring load to the diaphragm in a direction in which the seal surface of the valve is pressed against the peripheral edge of the opening of the flow path hole. Control device. In the valve opening and closing control device according to claim 4 or 5,
The negative pressure actuated actuator has a rod that moves in the axial direction in conjunction with the diaphragm,
The valve opening and closing control device, wherein the rod drives the valve. In the valve opening and closing control device according to claim 6,
The valve has a valve shaft that is rotatably supported by the housing, and is a flap-type valve that rotates around the axis of the valve shaft,
A valve opening / closing control device characterized in that a motion direction conversion mechanism for converting linear motion of the rod into rotational motion of the valve shaft is interposed between the rod and the valve shaft. The valve opening / closing control apparatus according to any one of claims 1 to 7, wherein the housing cools exhaust gas that flows out of the internal combustion engine and is recirculated to the intake system of the internal combustion engine. Connected to the inlet of the gas cooler,
The valve opening and closing control device according to claim 1, wherein the valve is disposed upstream of the exhaust gas cooler in the flow direction of the exhaust gas. The valve opening / closing control device according to claim 8,
Inside the housing, a cooler-side communication path for recirculating exhaust gas to the intake system of the internal combustion engine via the exhaust gas cooler, and exhaust gas to the intake system of the internal combustion engine by bypassing the exhaust gas cooler A bypass-side communication path for recirculation is formed,
The fluid flow path constitutes a part of the cooler side communication path,
The valve opening / closing control device, wherein the flow path hole constitutes a part of the bypass side communication path. In the valve opening and closing control device according to claim 9,
The valve opening / closing control device, wherein the valve constitutes a valve body of an opening / closing valve that opens and closes at least the bypass side communication path. In the valve opening and closing control device according to claim 9,
2. The valve opening / closing control apparatus according to claim 1, wherein the valve constitutes a valve body of a switching valve that switches between the cooler side communication path and the bypass side communication path.

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