JP2018003633A - Passage selector valve for exhaust gas recirculation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change-over flow passages when functions are changed over between LPL and HPL without communicating a first downstream side EGR passage with a second downstream side EGR passage.SOLUTION: A three-way valve 27 is provided with an upstream side passage part 42 for use in feeding EGR gas; a first downstream side passage part 43 for feeding out EGR gas to the first downstream side EGR passage; and a second downstream side passage part 44 for use in feeding out EGR gas to the second downstream side EGR passage. The first downstream side passage part 43 is provided with a first valve body 45 that is oscillated around a first rotating shaft 46 and can be sat on a first valve seat 43a at the valve seat 43a, the second downstream side passage part 44 is provided with a second valve body 47 that is oscillated around a second rotating shaft 48 and can be sat on a second valve seat 44a at a downstream side of the valve seat 44a. There is provided a cooperative driving mechanism 50 constituted to include an operating state in which the first valve body 45 and the second valve body 47 are cooperated to each other and the second valve body 47 is closed when the first valve body 45 is opened and another operating state in which the first valve body 45 is closed when the second valve body 47 is opened.SELECTED DRAWING: Figure 11

Description

  The present invention is an exhaust gas recirculation device for flowing a part of exhaust discharged from an engine as an exhaust gas recirculation gas into an intake passage and recirculating it to the engine. The exhaust gas recirculation apparatus includes both a so-called high pressure loop type and a low pressure loop type. The present invention relates to an exhaust gas recirculation device configured to be switched and used as necessary, and more particularly to a flow path switching valve used for switching an exhaust gas recirculation gas flow path.

  Conventionally, as this type of technology, for example, a control device for an internal combustion engine described in Patent Document 1 below is known. This device is provided in an engine equipped with a supercharger, and includes a high-pressure loop type exhaust gas recirculation device (hereinafter referred to as “EGR device”) and a low-pressure loop type EGR device. In the high-pressure loop type EGR device, an EGR valve is provided in an EGR passage that connects an exhaust passage upstream of the turbine and an intake passage downstream of the compressor. The low pressure loop type EGR device is provided with an EGR valve in an EGR passage that connects an exhaust passage downstream of the turbine and an intake passage upstream of the compressor.

  In general, in a system using both a high-pressure loop type and a low-pressure loop type, high-pressure EGR with better responsiveness can be implemented by a high-pressure loop type in a low-rotation low-load region that is not supercharged. On the other hand, low-pressure EGR that allows EGR gas to be well mixed into the intake air can be implemented by the low-pressure loop type in a middle-rotation middle load range or high-rotation high-load range that is during supercharging. This is because, in the low pressure loop type, EGR gas flowing from the EGR passage to the intake passage is returned to the engine through a long route passing through the compressor, the throttle valve, and the intake manifold.

  However, in the control device described in Patent Document 1, an EGR valve must be provided for each of the high-pressure loop type and the low-pressure loop type, which not only complicates the configuration but also tends to increase the cost of the entire device. It was. Further, in order to meet the demand for a large flow rate of EGR, both of the two EGR valves need to be motorized valves that can cope with the large flow rate, and in this respect as well, the entire apparatus tends to be expensive.

JP2012-163209A

  Here, for the EGR, it is desired that a high-pressure loop type function and a low-pressure loop type function can be selectively implemented, and that the implementation can be realized at a relatively low cost. For this purpose, it is conceivable to configure the EGR device as follows. That is, one EGR valve is provided in the EGR passage, and the EGR passage downstream from the EGR valve is branched into the first downstream EGR passage and the second downstream EGR passage. The outlet of the first downstream EGR passage is connected to the intake passage downstream of the throttle valve, and the outlet of the second downstream EGR passage is connected to the intake passage upstream of the throttle valve. In addition, a flow path switching valve for switching the flow path is provided at a branch portion of the EGR path to selectively flow EGR gas flowing through the EGR path to the first downstream EGR path and the second downstream EGR path. Then, the high-pressure loop type function and the low-pressure loop type function are switched by switching the flow path switching valve.

  However, in the above-described flow path switching valve, when switching the flow path, the flow path to the other is opened before the flow path to one of the first downstream EGR passage and the second downstream EGR passage is closed. Sometimes. For this reason, there is a possibility that the first downstream EGR passage and the second downstream EGR passage communicate with each other. For example, when switching from a low pressure loop type function to a high pressure loop type function, fresh air may flow into the engine (combustion chamber) via the first downstream EGR passage, and the engine output may fluctuate. On the other hand, when switching from the high pressure loop type function to the low pressure loop type function, the EGR gas may be excessively introduced into the engine (combustion chamber) via the second downstream EGR passage and the intake passage, and the emission may be deteriorated. is there. Further, when the intake pressure rises due to supercharging during the high pressure loop type function, fresh air may flow from the first downstream EGR passage into the exhaust passage through the upstream EGR passage.

  The present invention has been made in view of the above circumstances, and an object thereof is to switch the first downstream exhaust recirculation passage and the second downstream when switching their functions between the low pressure loop type and the high pressure loop type. An object of the present invention is to provide a flow path switching valve of an exhaust gas recirculation apparatus that can switch the flow path without communicating with the side exhaust gas recirculation passage.

  In order to achieve the above object, an invention according to claim 1 is an intake passage for introducing intake air into an engine, and an intake air amount adjusting valve provided in the intake passage for adjusting an intake air amount in the intake passage. In order to adjust the flow rate of the exhaust gas recirculation gas provided in the exhaust gas recirculation passage and the exhaust gas recirculation passage for flowing a part of the exhaust gas led out from the engine to the exhaust gas passage as the exhaust gas recirculation gas to the intake passage and recirculating to the engine The exhaust gas recirculation valve, the exhaust gas recirculation passage downstream from the exhaust gas recirculation valve are branched into a first downstream exhaust recirculation passage and a second downstream exhaust recirculation passage, and the first downstream exhaust recirculation passage is an intake air amount adjustment valve In the exhaust gas recirculation apparatus, the exhaust gas recirculation device is provided at a branch portion of the exhaust gas recirculation passage. The exhaust gas recirculation device includes a second downstream exhaust gas recirculation passage connected to an intake air passage upstream of the intake air amount adjustment valve. Is A flow path switching valve configured to switch a flow path so as to selectively flow exhaust gas recirculation gas flowing through an exhaust gas recirculation path to a first downstream exhaust recirculation path and a second downstream exhaust recirculation path, An upstream passage portion provided in the housing for introducing the exhaust gas recirculation gas flowing from the exhaust gas recirculation valve, and a first downstream side provided in the housing for deriving the exhaust gas recirculation gas to the first downstream exhaust recirculation passage A passage portion, a second downstream passage portion provided in the housing for leading exhaust recirculation gas to the second downstream exhaust recirculation passage; a first valve seat provided in the first downstream passage portion; In order to open and close the downstream side passage portion, a plate-like first plate is provided that can swing about the first rotation shaft and that can be seated on the first valve seat on the downstream side of the first valve seat. 1 valve body and a second provided in the second downstream passage portion In order to open and close the seat and the second downstream passage portion, it is provided so as to be swingable about the second rotation shaft, and is provided so as to be seated on the second valve seat on the downstream side of the second valve seat. The plate-shaped second valve body, the first valve body and the second valve body are opened and closed in conjunction with each other, and when the first valve body is opened, the second valve body is moved to the second valve seat. A first operation state in which the first valve body is seated on the first valve seat and the valve is closed when the second valve body is opened, It is intended to include an interlocking drive mechanism configured to switch between the first operation state and the second operation state.

  According to the configuration of the above invention, the interlocking drive mechanism interlocks the first valve body and the second valve body to open and close, and the second valve body is the first when the first valve body opens. A first operation state in which the two valve seats are seated and closed; and a second operation state in which the first valve body is seated on the first valve seat and the valve is closed when the second valve body is opened. And is configured to switch between a first operating state and a second operating state. Therefore, when one of the first valve body and the second valve body is opened, the other valve is closed. Therefore, when the valve is opened and closed, the first downstream passage section downstream from the first valve seat is used. And the second downstream passage portion downstream from the second valve seat do not communicate with each other. Further, in the first downstream passage portion of the flow path switching valve, a plate-shaped first valve body is provided so as to be able to swing around the first rotation shaft, and at the downstream side of the first valve seat. It is provided so as to be seated on the valve seat. Similarly, in the second downstream passage portion, a plate-like second valve body is provided so as to be swingable about the second rotation shaft, and is seated on the second valve seat downstream of the second valve seat. Provided possible. Therefore, when the first valve body is closed, the first valve body is moved to the first valve seat due to the pressure difference between the upstream side and the downstream side of the first downstream passage portion with the first valve seat as a boundary. Pressed against. Similarly, when the second valve body is closed, the second valve body is moved to the second valve due to a pressure difference between the upstream side and the downstream side of the second downstream passage portion with the second valve seat as a boundary. Pressed against the seat.

  In order to achieve the above object, the invention according to claim 2 is the invention according to claim 1, wherein the interlocking drive mechanism includes a first valve between the first operation state and the second operation state. It is intended to include a third operation state in which both the body and the second valve body are closed.

  According to the configuration of the invention, in addition to the operation of the invention according to claim 1, the interlocking drive mechanism is provided with the third operation state between the first operation state and the second operation state. At the time of switching between opening and closing of the first valve body and the second valve body, both the first valve body and the second valve body are once closed. Therefore, at the time of switching between valve opening and valve closing, the communication between the first downstream passage portion downstream from the first valve seat and the second downstream passage portion downstream from the second valve seat is reliably blocked.

  In order to achieve the above object, according to a third aspect of the present invention, in the first or second aspect of the present invention, the first rotating shaft is deviated from the flow of the exhaust gas recirculation gas in the first downstream passage portion. The second rotating shaft is arranged at a position shifted from the flow of the exhaust gas recirculation gas in the second downstream passage portion.

  According to the configuration of the above invention, in addition to the operation of the invention described in claim 1 or 2, in the first downstream passage portion, the first rotating shaft is disposed at a position deviated from the flow of the exhaust gas recirculation gas. In the downstream passage portion, the second rotation shaft is disposed at a position deviated from the flow of the exhaust gas recirculation gas, so that the first rotation shaft and the second rotation shaft are not easily exposed to the exhaust gas recirculation gas.

  In order to achieve the above object, the invention according to claim 4 is the first urging force for urging the first valve body in the valve closing direction in the invention according to any one of claims 1 to 3. The present invention further includes means and second urging means for urging the second valve body in the valve closing direction.

  According to the configuration of the invention, in addition to the operation of the invention according to any one of claims 1 to 3, the first valve body is urged in the valve closing direction by the first urging means, and the second valve body is It is urged in the valve closing direction by the second urging means. Therefore, when the valve is closed, each valve element is pressed against the corresponding valve seat by the urging force of each urging means.

  According to the first aspect of the invention, when the function is switched between the low pressure loop type and the high pressure loop type, the first downstream exhaust recirculation passage and the second downstream exhaust recirculation passage are not communicated with each other. The flow path can be switched. Moreover, the sealing performance between each valve body and each corresponding valve seat can be improved when the first valve body or the second valve body is closed.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, when the function is switched between the low pressure loop type and the high pressure loop type, the first downstream exhaust recirculation passage and the second Communication with the downstream exhaust gas recirculation passage can be reliably prevented.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, it is possible to prevent the condensed water and deposits from adhering to the first rotating shaft and the second rotating shaft. Corrosion and sticking of the shaft can be prevented.

  According to the invention of claim 4, in addition to the effect of the invention of any of claims 1 to 3, when the first valve body or the second valve body is closed, it corresponds to each valve body. The sealing performance between the valve seats can be improved.

1 is a schematic configuration diagram showing a gasoline engine system according to an embodiment. The perspective view which concerns on one Embodiment and shows a three-way valve. The front view which concerns on one Embodiment and shows a three-way valve. The rear view which concerns on one Embodiment and shows a three-way valve. The top view which concerns on one Embodiment and shows a three-way valve. The bottom view showing a three-way valve concerning one embodiment. The right view which concerns on one Embodiment and shows a three-way valve. The left view which concerns on one Embodiment and shows a three-way valve. FIG. 9 is a cross-sectional view taken along line AA of FIG. 8 illustrating one operation of the three-way valve according to the embodiment. FIG. 9 is a cross-sectional view taken along line AA of FIG. 8 illustrating another operation of the three-way valve according to the embodiment. Schematic which shows the 1st operation state of an interlocking drive mechanism, and the operation state of each valve body which fractures a part of housing, concerning one embodiment. The schematic diagram which concerns on one Embodiment and shows the 3rd operation state of an interlocking drive mechanism, and the operation state of each valve body by fracture | rupturing a part of housing. The schematic diagram which concerns on one Embodiment and shows the 2nd operation state of an interlocking drive mechanism, and the operation state of each valve body by fracture | rupturing a part of housing.

  Hereinafter, an embodiment in which a flow path switching valve of an exhaust gas recirculation apparatus in the present invention is embodied in a gasoline engine system will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration diagram of a gasoline engine system in this embodiment. A gasoline engine system mounted on an automobile includes a reciprocating engine 1. The engine 1 is provided with an intake passage 2 for introducing intake air into each cylinder and an exhaust passage 3 for deriving exhaust gas from each cylinder. A supercharger 5 is provided in the intake passage 2 and the exhaust passage 3. The intake passage 2 is provided with an air cleaner 4, a compressor 5 a of the supercharger 5, an intercooler 6, a throttle device 7, and an intake manifold 8. The throttle device 7 adjusts the amount of intake air in the intake passage 2 by opening and closing a butterfly throttle valve 7a. In this embodiment, the throttle device 7 corresponds to an example of an intake air amount adjustment valve of the present invention. The intake manifold 8 includes a surge tank 8a and a plurality of branch passages 8b that branch from the surge tank 8a to each cylinder. The exhaust passage 3 is provided with a turbine 5b of the supercharger 5 and a catalyst 10 for purifying exhaust gas. The engine 1 has a known configuration, combusts a mixture of fuel and intake air, and discharges the exhaust after combustion to the exhaust passage 3. In the supercharger 5, the turbine 5 b rotates by the flow of exhaust gas, and the compressor 5 a rotates in conjunction with the rotation of the turbine 5 b, thereby boosting the intake air in the intake passage 2.

  This engine system includes an exhaust gas recirculation device (EGR device) 21. This device 21 includes an exhaust gas recirculation passage (EGR passage) 22 for flowing a part of exhaust discharged from each cylinder to the exhaust passage 3 as exhaust gas recirculation gas (EGR gas) to the intake passage 2 and recirculating it to each cylinder. The exhaust gas recirculation cooler (EGR cooler) 23 provided in the EGR passage 22 for cooling the EGR gas, and the exhaust gas recirculation valve provided in the EGR passage 22 downstream of the EGR cooler 23 for adjusting the flow rate of the EGR gas. (EGR valve) 24. The EGR passage 22 includes an upstream EGR passage 22A upstream from the EGR valve 24, and a portion downstream from the EGR valve 24 includes a first downstream exhaust recirculation passage (first downstream EGR passage) 22B and a second downstream exhaust. The flow is branched to the reflux passage (second downstream EGR passage) 22C. The first downstream EGR passage 22B is connected to the intake passage 2 (intake manifold 8) downstream from the throttle device 7. The second downstream EGR passage 22C is connected to the intake passage 2 upstream of the throttle device 7 and the compressor 5a. The EGR passage 22 includes a reflux inlet 22a that opens to the upstream end of the upstream EGR passage 22A, a reflux first outlet 22b that opens to the downstream end of the first downstream EGR passage 22B, and a downstream of the second downstream EGR passage 22C. And a reflux second outlet 22c opening at the end. The recirculation inlet 22a communicates with the exhaust passage 3 downstream from the catalyst 10, and the recirculation first outlet 22b communicates with the intake passage 2 (each branch passage 8b of the intake manifold 8) downstream from the throttle device 7, The outlet 22c communicates with the intake passage 2 upstream from the compressor 5a. In this embodiment, the downstream portion of the first downstream EGR passage 22B is a distribution pipe 26 including four reflux first outlets 22b for distributing the EGR gas flowing through the passage 22B to each branch passage 8b. . The reason why the plurality of first reflux outlets 22b communicate with the respective branch passages 8b is to introduce the EGR gas evenly into the respective branch passages 8b.

  In this embodiment, the EGR valve 24 is configured by an electrically operated valve having a variable opening. The EGR valve 24 desirably has characteristics of a large flow rate, high response, and high resolution. Therefore, in this embodiment, as a structure of the EGR valve 24, for example, a “double eccentric valve” described in Japanese Patent No. 5759646 can be adopted as a basic configuration. This double eccentric valve is configured for large flow control. Here, detailed description of the EGR valve 24 is omitted.

  In this embodiment, a three-way valve 27 is provided at the branch portion of the EGR passage 22. The three-way valve 27 is configured to switch the flow path so that the EGR gas flowing through the upstream EGR passage 22A selectively flows into the first downstream EGR passage 22B and the second downstream EGR passage 22C. The three-way valve 27 includes a first port 27a, a second port 27b, and a third port 27c. One end of the upstream EGR passage 22A is connected to the first port 27a, one end of the first downstream EGR passage 22B is connected to the second port 27b, and one end of the second downstream EGR passage 22C is connected to the third port 27c. Connected to. When the three-way valve 27 is turned on / off, the flow of the EGR gas led out from the upstream EGR passage 22A to the first port 27a is changed to the first downstream EGR passage 22B and the second downstream EGR passage 22C. Are selectively switched between. That is, by turning off the three-way valve 27, the third port 27c is shut off, the first port 27a and the second port 27b are communicated, and the EGR gas flowing into the upstream EGR passage 22A from the reflux inlet 22a It flows from the first reflux outlet 22b to each branch passage 8b (a so-called high-pressure loop type function, hereinafter referred to as an “HPL function” for convenience). On the other hand, when the three-way valve 27 is turned on, the second port 27b is shut off, the first port 27a and the third port 27c are communicated, and the EGR gas flowing into the upstream EGR passage 22A from the reflux inlet 22a It flows from the recirculation second outlet 22c to the intake passage 2 upstream of the compressor 5a (a so-called low-pressure loop type function; hereinafter referred to as “LPL function” for convenience). That is, the EGR device 21 has an HPL function that allows EGR gas to flow from the exhaust passage 3 downstream of the catalyst 10 to the intake passage 2 (each branch passage 8b of the intake manifold 8) downstream of the throttle device 7, and the catalyst 10 It also has an LPL function that allows EGR gas to flow from the exhaust passage 3 downstream from the throttle device 7 and the compressor 5 a to the intake passage 2 downstream from the air cleaner 4. In this embodiment, the three-way valve 27 corresponds to an example of the flow path switching valve of the present invention.

  Next, the configuration of the three-way valve 27 will be described in detail below. FIG. 2 is a perspective view of the three-way valve 27. FIG. 3 is a front view of the three-way valve 27. FIG. 4 shows the three-way valve 27 in a rear view. FIG. 5 shows the three-way valve 27 in a plan view. FIG. 6 shows the three-way valve 27 in a bottom view. FIG. 7 is a right side view of the three-way valve 27. FIG. 8 is a left side view of the three-way valve 27. FIG. 9 shows an operation of the three-way valve 27 by a cross-sectional view taken along line AA in FIG. FIG. 10 shows another operation of the three-way valve 27 by a cross-sectional view taken along line AA in FIG. As shown in FIGS. 2 to 10, the three-way valve 27 is provided inside the housing 41 and the housing 41, and introduces EGR gas from the EGR passage 22 (upstream EGR passage 22 </ b> A) upstream from the EGR valve 24. Provided in the housing 41, the first downstream passage portion 43 for leading the EGR gas to the first downstream EGR passage 22B, the housing 41, And a second downstream passage portion 44 for deriving EGR gas to the downstream EGR passage 22C. The inlet of the upstream passage portion 42 is the first port 27a, the outlet of the first downstream passage portion 43 is the second port 27b, and the outlet of the second downstream passage portion 44 is the third port 27c.

  In this embodiment, the EGR valve 24 is integrally fixed to the three-way valve 27. That is, as shown in FIGS. 2 to 10, the housing 31 of the EGR valve 24 is fixed to the first port 27 a of the housing 41. A valve seat 32 is provided in the flow path 31 a in the housing 31, and a valve body 33 provided so as to be able to be seated on the valve seat 32 is provided so as to be rotatable about a rotation shaft 34. 9 and 10, the EGR valve 24 shows a closed state in which the valve element 33 is seated on the valve seat 32.

  As shown in FIGS. 9 and 10, the first downstream passage portion 43 is provided with a first valve seat 43a, and a plate-like first valve body 45 corresponding to the first valve seat 43a is provided. Provided. The first valve body 45 is provided so as to be swingable about the first rotation shaft 46 in order to open and close the first downstream passage portion 43, and at the downstream side of the first valve seat 43a, the first valve seat 45a is provided. 43a is provided so that it can be seated. The first valve seat 43 a is formed obliquely in the first downstream passage portion 43. In the first downstream passage portion 43, the first rotation shaft 46 is disposed at a position deviated from the flow of EGR gas, that is, at a position away from the center of the first downstream passage portion 43.

  As shown in FIGS. 9 and 10, the second downstream passage portion 44 is provided with a second valve seat 44a, and a second valve body 47 having a plate shape corresponding to the second valve seat 44a. Provided. The second valve body 47 is provided so as to be able to swing around the second rotating shaft 48 in order to open and close the second downstream passage portion 44, and at the downstream side of the second valve seat 44a, the second valve seat 44a. 44a is slidably provided. The second valve seat 44 a is formed obliquely in the second downstream side passage portion 44. In the second downstream passage portion 44, the second rotation shaft 48 is disposed at a position deviated from the flow of EGR gas, that is, at a position away from the center of the second downstream passage portion 44.

  As shown in FIGS. 2 to 10, the three-way valve 27 includes an interlocking drive mechanism 50 for opening and closing the first valve body 45 and the second valve body 47 in conjunction with each other. As shown in FIG. 10, the interlock drive mechanism 50 includes a first operation state in which the second valve body 47 is seated on the second valve seat 44a and closed when the first valve body 45 is opened, As shown in FIG. 9, when the second valve body 47 opens, the first valve body 45 sits on the first valve seat 43a and closes, and the first operation state And the second operating state. That is, the interlocking drive mechanism 50 is configured such that when one of the first valve body 45 and the second valve body 47 is opened, the other is closed. In addition, in this embodiment, the interlocking drive mechanism 50 is a third valve that closes both the first valve body 45 and the second valve body 47 between the first operation state and the second operation state. It is configured to include an operating state.

  The configuration of the interlocking drive mechanism 50 will be described in detail. 2-10, the both ends of the 1st rotating shaft 46 are rotatably supported by the housing 41 via the 1st bearing 51. As shown in FIG. Further, both end portions of the second rotating shaft 48 are rotatably supported by the housing 41 via the second bearing 52. The interlocking drive mechanism 50 includes a diaphragm actuator (hereinafter simply referred to as “actuator”) 56 that operates by receiving a negative pressure, a link 57 and a first lever 58 fixed to one end of the first rotating shaft 46. The second lever 59 is fixed to one end of the second rotating shaft 48, and the connecting cam 60 is rotatably supported at the tip of the second lever 59.

  The actuator 56 is supported with respect to the housing 41 via a bracket 61. The actuator 56 has a well-known structure, and when the negative pressure is introduced from the negative pressure port 56a to the inside, the operating rod 56b contracts, and when the introduction of the negative pressure to the inside is interrupted, the operating rod 56b is It is designed to stretch. In this embodiment, the negative pressure generated in the intake passage 2 is used as the negative pressure for operating the actuator 56. The introduction and interruption of the negative pressure with respect to the actuator 56 is controlled by turning on / off a predetermined VSV (not shown).

  The link 57 has a first end portion 57a and a second end portion 57b, and is fixed to the first rotating shaft 46 at a substantially central portion. The first lever 58 is fixed to the first rotation shaft 46 outside the link 57. The first end 57a of the link 57 is rotatably connected to the tip of the operating rod 56b. The tip of the first lever 58 is disposed so as to be engageable with the tip of the operating rod 56b. The connecting cam 60 has a long hole 60 a and one end thereof is connected to the tip of the second lever 59 so as to be rotatable. Further, the second end 57b of the link 57 is slidably connected to the long hole 60a. A first spring 62 for biasing the first valve body 45 in the valve closing direction is provided between the first rotating shaft 46 and the housing 41. The first spring 62 corresponds to an example of the first urging means of the present invention. Between the 2nd rotating shaft 48 and the housing 41, the 2nd spring 63 for urging | biasing the 2nd valve body 47 in the valve closing direction is provided. The second spring 63 corresponds to an example of the second urging means of the present invention.

  Next, the relationship between the operation of the interlock drive mechanism 50 and the opening / closing operations of the first valve body 45 and the second valve body 47 will be described. FIG. 11 is a schematic view showing a first operation state of the interlocking drive mechanism 50 and operation states of the valve bodies 45 and 47 with a part of the housing 41 broken away. FIG. 12 is a schematic view showing a third operation state of the interlocking drive mechanism 50 and the operation states of the valve bodies 45 and 47 with a part of the housing 41 broken away. FIG. 13 is a schematic view of the second operation state of the interlocking drive mechanism 50 and the operation states of the valve bodies 45 and 47 with a part of the housing 41 broken away. First, when the supply of negative pressure to the actuator 56 is interrupted, the interlocking drive mechanism 50 enters the first operation state as shown in FIG. That is, the operating rod 56b of the actuator 56 extends to the maximum extent. At this time, the link 57 rotates counterclockwise around the first rotation shaft 46 and tilts obliquely upward to the right. Further, the second lever 59 rotates clockwise together with the second rotation shaft 48 via the link 57 and the connecting cam 60, but the second end portion 57 b of the link 57 is engaged with the upper end of the long hole 60 a of the connecting cam 60. When combined, the movement of the interlocking drive mechanism 50 stops. As a result, the first valve body 45 is opened and the second valve body 47 is closed. Since the first valve body 45 is opened, the EGR gas that has flowed into the upstream passage portion 42 from the EGR valve 24 flows toward the first downstream passage portion 43 as indicated by a thick arrow. As a result, the EGR device 21 has an HPL function that allows EGR gas to flow from the exhaust passage 3 downstream of the catalyst 10 to the intake passage 2 (each branch passage 8b of the intake manifold 8) downstream of the throttle device 7.

  When negative pressure starts to be supplied to the actuator 56 from the first operation state, the interlocking drive mechanism 50 enters the third operation state as shown in FIG. In this state, the operating rod 56b of the actuator 56 starts to contract, and the link 57 starts to rotate clockwise about the first rotation shaft 46. Then, the second end portion 57b of the link 57 slides to the lower end along the long hole 60a of the connection cam 60, and the torque of the link 57 is not transmitted to the connection cam 60 during the slide. The second lever 59 is urged to rotate clockwise along with the second rotating shaft 48 by the second spring 63. Thereby, both the 1st valve body 45 and the 2nd valve body 47 close. Thus, the period during which both valve bodies 45 and 47 are closed is determined by the length of the long hole 60 a of the connecting cam 60. Since both valve bodies 45 and 47 are closed, the upstream side passage portion 42, the first downstream side passage portion 43 downstream from the first valve seat 43a, and the second downstream side downstream from the second valve seat 44a. Communication with the passage portion 44 is blocked.

  Thereafter, when further negative pressure is supplied to the actuator 56, the interlocking drive mechanism 50 enters the second operation state as shown in FIG. In this state, the operating rod 56b of the actuator 56 contracts to the maximum extent. At this time, the link 57 further rotates clockwise about the first rotation shaft 46, and the second lever 59 rotates together with the second rotation shaft 48 counterclockwise via the link 57 and the connecting cam 60. . As a result, the first valve body 45 is closed and the second valve body 47 is opened. Since the second valve body 47 is opened, the EGR gas flowing from the EGR valve 24 into the upstream passage portion 42 flows toward the second downstream passage portion 44 as indicated by a thick arrow. As a result, the EGR device 21 has an LPL function capable of flowing EGR gas from the exhaust passage 3 downstream from the catalyst 10 to the throttle device 7 and the intake passage 2 upstream from the compressor 5a.

  According to the configuration of the three-way valve 27 of the EGR device 21 in this embodiment described above, the interlocking drive mechanism 50 opens and closes the first valve body 45 and the second valve body 47 in conjunction with each other, and A first operating state in which the second valve body 47 is seated on the second valve seat 44a and closed when the one valve body 45 is opened, and the first valve body 47 is opened when the second valve body 47 is opened. 45 includes a second operation state in which the first valve seat 43a is seated and closed, and is configured to switch between the first operation state and the second operation state. Accordingly, when one of the first valve body 45 and the second valve body 47 is opened, the other valve is closed. Therefore, when the valve is opened and closed, the first downstream of the first valve seat 43a is downstream. The side passage portion 43 and the second downstream passage portion 44 downstream from the second valve seat 44a do not communicate with each other. For this reason, when the function is switched between the LPL type and the HPL type, the flow path can be switched without causing the first downstream EGR passage 22B and the second downstream EGR passage 22C to communicate with each other. As a result, at the time of switching from the LPL function to the HPL function, it is possible to prevent the fresh air from flowing into the engine 1 (combustion chamber) through the first downstream EGR passage 22B and changing the output of the engine 1. . On the other hand, when switching from the HPL function to the LPL function, it is possible to prevent the EGR gas from being excessively introduced into the engine 1 (combustion chamber) via the second downstream EGR passage 22C and the intake passage 2 to deteriorate the emission. Can do.

  According to the configuration of the three-way valve 27 in this embodiment, in the first downstream-side passage portion 43, the plate-shaped first valve body 45 is provided so as to be able to swing around the first rotation shaft 46, and the first It is provided so as to be seated on the first valve seat 43a on the downstream side of the valve seat 43a. Similarly, in the second downstream passage portion 44, a plate-shaped second valve body 47 is provided so as to be swingable about the second rotation shaft 48, and at the second downstream side of the second valve seat 44a. It is provided so as to be seated on the valve seat 44a. Therefore, when the first valve body 45 is closed, the first valve body 45 is caused by the pressure difference between the upstream side and the downstream side of the first downstream passage portion 43 with the first valve seat 43a as a boundary. It is pressed against the first valve seat 43a. Similarly, when the second valve body 47 is closed, the second valve body 47 is caused by a pressure difference between the upstream side and the downstream side of the second downstream passage portion 44 with the second valve seat 44a as a boundary. Is pressed against the second valve seat 44a. For this reason, when the valve bodies 45 and 47 are closed, the sealing performance between the valve bodies 45 and 47 and the corresponding valve seats 43a and 44a can be improved. That is, when the first valve body 45 is closed, the sealing performance between the first valve body 45 and the first valve seat 43a can be improved. In addition, when the second valve body 47 is closed, the sealing performance between the second valve body 47 and the second valve seat 44a can be improved.

  For example, as shown in FIG. 9, during the LPL function, the second valve body 47 is opened and EGR gas (shown by a shaded arrow) is derived from the second downstream passage portion 44. Even if the intake pressure (indicated by a white arrow) rises due to the supply, the first valve body 45 is pressed against the first valve seat 43a, so that the intake air is drawn from between the first valve body 45 and the first valve seat 43a. Will not leak. In addition, it is possible to prevent intake air (fresh air) from flowing into the exhaust passage 3 from the first downstream passage portion 43 via the upstream passage portion 42 and the upstream EGR passage 22A. On the other hand, as shown in FIG. 10, in the HPL function, the first valve body 45 is opened, and EGR gas (indicated by a shaded arrow) is derived by the negative pressure acting on the first downstream passage portion 43. However, negative pressure (indicated by a white arrow) acts on the second valve body 47, and the second valve body 47 is pressed against the second valve seat 44a. For this reason, intake air does not leak from between the second valve body 47 and the second valve seat 44a. Here, even if each valve body 45, 47 or each valve seat 43a, 44a is provided with a seal member, when the valve body 45, 47 is opened or closed, each valve body 45, 47 has a corresponding valve seat 43a, 44a. Since it does not slide, the open / close response of the valve bodies 45 and 47 is not affected.

  According to the configuration of the three-way valve 27 in this embodiment, the interlocking drive mechanism 50 is provided with the third operation state between the first operation state and the second operation state. When the second valve body 47 is opened and closed, both the first valve body 45 and the second valve body 47 are once closed. Therefore, when the valve is opened and closed, the communication between the first downstream passage portion 43 downstream from the first valve seat 43a and the second downstream passage portion 44 downstream from the second valve seat 44a is reliably blocked. The For this reason, when the function is switched between the LPL type and the HPL type, communication between the first downstream EGR passage 22B and the second downstream EGR passage 22C can be reliably prevented.

  According to the configuration of the three-way valve 27 in this embodiment, the first rotary shaft 46 is disposed at a position shifted from the flow of the EGR gas in the first downstream passage portion 43, and the second downstream passage portion 44 has the first Since the two rotation shafts 48 are disposed at positions deviated from the flow of the EGR gas, the first rotation shaft 46 and the second rotation shaft 48 are not easily exposed to the EGR gas. For this reason, it is possible to prevent the condensed water and deposits from adhering to the rotary shafts 46 and 48 and the bearings 51 and 52, and to prevent the rotary shafts 46 and 48 and the bearings 51 and 52 from corroding and sticking. .

  According to the configuration of the three-way valve 27 in this embodiment, the first valve body 45 is biased in the valve closing direction by the first spring 62, and the second valve body 47 is biased in the valve closing direction by the second spring 63. The Therefore, when the valve is closed, the valve bodies 45 and 47 are pressed against the corresponding valve seats 43a and 44a by the urging force of the springs 62 and 63. For this reason, when the 1st valve body 45 or the 2nd valve body 47 closes, the sealing performance between each valve body 45 and 47 and each valve seat 43a, 44a corresponding can be improved.

  According to the configuration of the three-way valve 27 in this embodiment, since the EGR valve 24 is provided integrally, the three-way valve 27 and the EGR valve 24 can be handled as one assembly, and the three-way valve 27 and the EGR valve 24 The assembling work for the EGR passage 22 can be simplified.

  In addition, this invention is not limited to the said embodiment, A part of structure can also be changed suitably and implemented in the range which does not deviate from the meaning of invention.

  (1) In the above embodiment, the interlock drive mechanism 50 of the three-way valve 27 is configured to include the first operation state, the second operation state, and the third operation state, but the third operation state is omitted. be able to.

  (2) In the above embodiment, the interlocking drive mechanism 50 of the three-way valve 27 is configured to be driven by the diaphragm actuator 56, but it can also be configured to be driven by a motor instead of the diaphragm actuator 56.

  (3) In the above embodiment, the EGR valve 24 is provided integrally with the three-way valve 27. However, the EGR valve may be provided separately from the three-way valve.

  The present invention can be applied to an EGR apparatus that includes both a so-called high-pressure loop type and a low-pressure loop type, and is configured to switch both types as necessary.

1 Engine 2 Intake passage 3 Exhaust passage 7 Throttle device (intake air amount adjustment valve)
21 EGR device (exhaust gas recirculation device)
22 EGR passage (exhaust gas recirculation passage)
22A Upstream EGR passage (Upstream exhaust recirculation passage)
22B First downstream EGR passage (first downstream exhaust recirculation passage)
22C Second downstream EGR passage (second downstream exhaust recirculation passage)
24 EGR valve (exhaust gas recirculation valve)
27 Three-way valve (flow path switching valve)
41 Housing 42 Upstream passage portion 43 First downstream passage portion 43a First valve seat 44 Second downstream passage portion 44a Second valve seat 45 First valve body 46 First rotating shaft 47 Second valve body 48 Second rotation Shaft 50 Interlocking drive mechanism 62 First spring (first biasing means)
63 Second spring (second biasing means)

Claims (4)

An intake passage for introducing intake air into the engine;
An intake air amount adjusting valve provided in the intake passage for adjusting the intake air amount in the intake passage;
An exhaust gas recirculation passage for causing a part of the exhaust gas led out from the engine to the exhaust air passage to flow into the intake air passage as exhaust gas recirculation gas and recirculate to the engine;
An exhaust gas recirculation valve provided in the exhaust gas recirculation passage for adjusting the flow rate of the exhaust gas recirculation gas;
The exhaust gas recirculation passage downstream from the exhaust gas recirculation valve is branched into a first downstream exhaust recirculation passage and a second downstream exhaust recirculation passage;
The first downstream exhaust recirculation passage is connected to the intake passage downstream from the intake air amount adjustment valve, and the second downstream exhaust recirculation passage is connected to the intake passage upstream from the intake air amount adjustment valve. The exhaust gas recirculation device is provided at a branch portion of the exhaust gas recirculation passage, and the exhaust gas recirculation gas flowing through the exhaust gas recirculation passage is supplied to the first downstream exhaust recirculation passage and the second downstream exhaust recirculation passage. A flow path switching valve configured to switch flow paths for selective flow,
A housing;
An upstream passage portion provided in the housing for introducing the exhaust gas recirculation gas flowing from the exhaust gas recirculation valve;
A first downstream passage portion provided in the housing for leading the exhaust recirculation gas to the first downstream exhaust recirculation passage;
A second downstream passage portion provided in the housing for leading the exhaust recirculation gas to the second downstream exhaust recirculation passage;
A first valve seat provided in the first downstream passage portion;
In order to open and close the first downstream passage portion, it is provided so as to be swingable around a first rotating shaft, and is provided so as to be seated on the first valve seat on the downstream side of the first valve seat. A plate-shaped first valve body;
A second valve seat provided in the second downstream passage portion;
In order to open and close the second downstream passage portion, it is provided so as to be swingable about the second rotation shaft, and is provided so as to be seated on the second valve seat on the downstream side of the second valve seat. A plate-shaped second valve body;
The first valve body and the second valve body are opened and closed in conjunction with each other, and when the first valve body is opened, the second valve body is seated on the second valve seat and closed. A first operating state in which the valve is operated, and a second operating state in which the first valve body is seated on the first valve seat and is closed when the second valve body is opened. A flow path switching valve for an exhaust gas recirculation apparatus, comprising: an interlocking drive mechanism configured to switch between the operation state and the second operation state.   The interlock drive mechanism includes a third operation state in which both the first valve body and the second valve body are closed between the first operation state and the second operation state. The flow path switching valve of the exhaust gas recirculation apparatus according to claim 1, wherein the flow path switching valve is configured.   In the first downstream passage portion, the first rotation shaft is disposed at a position shifted from the flow of the exhaust gas recirculation gas. In the second downstream passage portion, the second rotation shaft is disposed in the exhaust gas recirculation gas. The flow path switching valve of the exhaust gas recirculation apparatus according to claim 1 or 2, wherein the flow path switching valve is disposed at a position deviated from the flow of the exhaust gas.   A first urging means for urging the first valve body in the valve closing direction; and a second urging means for urging the second valve body in the valve closing direction. The flow path switching valve of the exhaust gas recirculation apparatus according to any one of claims 1 to 3.

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