JP2018004030A - Double eccentric valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the contact wear of a valve body and a valve seat by suppressing the vibration of the valve body even if a negative pressure fluid acts on the valve body at a valve-opening from a full-closed state, and to stabilize a fluid flow rate characteristic.SOLUTION: An EGR valve including a double eccentric valve comprises a valve seat 38, a valve body 39, a rotating shaft 40 and a flow passage. The flow passage is branched to an upstream-side flow passage 36A and a downstream-side flow passage 36B with the valve seat 38 as a boundary, and the valve body 39 is arranged at the downstream-side flow passage 36B. The valve body 39 includes a first side part 39A and a second side part 39B with a virtual face V1 extending in parallel with a direction in which an axial line L2 of the valve body 39 extends from an axial line L1 of the rotating shaft 40 as a boundary. When the valve body 39 turns to a valve-opening direction from the full-closed state, the first side part 39A turns to the upstream-side flow passage 36A, and the second side part 39B turns to the downstream-side flow passage 36B. In order to regulate the turn of the valve body 39 in the full-closed state to a valve-closing direction, a valve-closing stopper 65 is arranged at the first side part 39A so as to be lockable. A spring for turning and energizing the valve body 39 in the full-closed state to the valve-closing direction is arranged.SELECTED DRAWING: Figure 6

Description

  In the present invention, the axis of the rotary shaft, which is the center of rotation of the valve body, is arranged away from the sealing surface of the valve body (primary eccentricity), and is arranged away from the axis of the valve body (secondary eccentricity). It relates to a heavy eccentric valve.

  Conventionally, as this type of technology, for example, a double eccentric valve described in Patent Document 1 below is known. This double eccentric valve is configured to improve the sealing performance when fully closed and to prevent wear due to drag between the valve body and the valve seat when the valve body rotates. That is, this double eccentric valve has a valve seat including a valve hole and a seat surface formed at an edge of the valve hole, a valve body having a seal surface corresponding to the seat surface formed on the outer periphery, and a valve body. A rotating shaft to be moved, a driving mechanism for rotating the rotating shaft, and a bearing for supporting the rotating shaft are provided, and the valve seat and the valve body are arranged in a flow path through which fluid flows. The flow path is divided into an upstream flow path and a downstream flow path with respect to the flow of the fluid with the valve seat as a boundary, and the valve element is disposed in the upstream flow path. Here, the double eccentric valve is configured such that a biasing force is applied to the drive mechanism side of the rotary shaft in order to press the valve body and the valve body side of the rotary shaft toward the valve seat with the bearing as a fulcrum. Is done. Then, in order to prevent foreign matter from being caught between the valve body and the valve seat when fully closed and the rotating shaft is locked, the rotating shaft is cantilevered by the housing, Some bearing play is allowed between the seats. Further, in order to prevent gas leakage from between the valve body and the valve seat when fully closed, a bearing back is utilized and the valve body is brought into contact with the valve seat and sealed by a drive mechanism.

International Publication No. 2016/002599

  Here, the double eccentric valve described in Patent Document 1 is employed as a configuration of an exhaust gas recirculation valve (EGR valve) that adjusts the flow rate of exhaust gas recirculation gas (EGR gas) in the exhaust gas recirculation passage (EGR passage) of the engine. be able to. In this case, when the EGR valve opens from the fully closed state, if the intake negative pressure acts on the valve body from the downstream side flow path, the valve body is pulled toward the valve seat. At this time, the valve body vibrates in a predetermined small opening range, and the valve body comes into contact with the valve seat along with the vibration, and there is a possibility that the valve seat and the valve body are worn. Further, the opening degree of the valve body becomes unstable as much as the valve body vibrates, and the EGR gas flow rate characteristic may become unstable. These problems are considered to be particularly prominent in a minute opening range of the EGR valve (for example, a range around “0 to 5 °”).

  The present invention has been made in view of the above circumstances, and its purpose is to suppress the vibration of the valve body even when negative pressure fluid acts on the valve body when the valve is opened from the fully closed state. An object of the present invention is to provide a double eccentric valve capable of suppressing contact wear between a body and a valve seat and stabilizing fluid flow characteristics.

  In order to achieve the above-mentioned object, the invention according to claim 1 is formed in an annular shape, a valve seat including an annular seat surface formed in the valve hole and the valve hole, a disc shape, and a seat surface. A valve body having a corresponding annular sealing surface formed on the outer periphery, a housing including a flow path through which a fluid flows, the valve seat and the valve body are disposed in the flow path, and the flow path with the valve seat as a boundary Divided into an upstream channel and a downstream channel, a valve body is disposed in the downstream channel, a rotating shaft for rotating the valve body, and a rotating shaft for rotatably supporting the rotating shaft in the housing The shaft of the valve body and the axis of the rotary shaft are arranged away from the sealing surface of the valve body, and the valve body is arranged away from the axis of the valve body, and the axis of the valve body extends from the axis of the rotary shaft. From the fully closed state in which the valve body is seated on the valve seat, including the first side and the second side with a virtual plane extending parallel to the direction as a boundary A double eccentric comprising: when the valve is pivoted in a direction, the first side is pivoted toward the upstream channel and the second side is pivoted toward the downstream channel; In the valve, a valve closing stopper provided to be engageable with the first side portion in order to restrict the rotation toward the valve closing direction opposite to the valve opening direction with respect to the fully closed valve body; Further, the present invention is intended to include rotation urging means for urging and energizing the fully closed valve body in the valve closing direction.

  According to the configuration of the above invention, the fully closed valve body seated on the valve seat is urged to rotate in the valve closing direction by the rotation urging means, but the first side portion of the valve body is closed. Since it engages with the stopper, further rotation in the valve closing direction is restricted, and the fully closed state is maintained. At this time, the valve body is urged to rotate in the valve closing direction with the engaging portion of the first side portion of the valve closing stopper as a fulcrum, and the valve body slightly moves, so that the sealing surface is the seat of the valve seat. Touch the surface. Further, even when negative pressure fluid acts on the downstream flow path and the fully closed valve body is pulled by the negative pressure fluid, the first side portion of the valve body is engaged with the valve closing stopper, Lifting from the body valve seat is restricted. On the other hand, when the negative pressure fluid acts on the downstream flow path and the valve body opens from the fully closed state, the valve body is pulled by the negative pressure fluid, and the first side portion thereof serves as the valve closing stopper. The valve begins to open while engaging.

  In order to achieve the above object, the invention according to claim 2 is the invention according to claim 1, in which the engagement portion with the first side portion of the valve closing stopper or the valve closing stopper of the first side portion is provided. The engagement portion forms a convex curved surface.

  According to the configuration of the above invention, in addition to the operation of the invention according to claim 1, in the minute valve opening region, the engagement portion between the first side portion of the valve body and the valve closing stopper moves along the convex curved surface. While the valve body starts to open.

  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 valve body is fully closed and a high negative pressure fluid acts on the downstream flow path. In some cases, another rotation biasing means for further biasing the valve body in the valve closing direction is further provided.

  According to the configuration of the above invention, in addition to the operation of the invention described in claim 1 or 2, when the valve body is in a fully closed state and the high negative pressure fluid acts on the downstream side flow path, The valve body is further urged to rotate in the valve closing direction by the moving urging means. Therefore, even when a high negative pressure fluid acts, the lift of the valve body from the valve seat is restricted, the valve body finely moves, and the seal surface comes into contact with the seat surface of the valve seat.

  According to the first aspect of the present invention, even when negative pressure fluid acts on the valve body when the valve is opened from the fully closed state, vibration of the valve body can be suppressed, and thereby contact between the valve body and the valve seat can be suppressed. Abrasion can be suppressed and the flow characteristics of the fluid can be stabilized. Further, when fully closed, the gap between the valve body and the valve seat can be sealed, and fluid leakage can be suppressed.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the load of the engaging portion between the valve body and the valve closing stopper can be distributed, and the valve body can be opened. You can start smoothly.

  According to the invention of the third aspect, in addition to the effect of the invention of the first or second aspect, even if the high negative pressure fluid acts on the valve body when fully closed, the gap between the valve body and the valve seat is not affected. Sealing can be ensured, and fluid leakage can be effectively suppressed.

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 an EGR valve. The perspective view which concerns on one Embodiment and shows a partially broken valve part in a fully-closed state. The perspective view which concerns on one Embodiment and shows the valve part in a fully open state partly broken. 1 is a plan sectional view showing an EGR valve in a fully closed state according to one embodiment. Sectional drawing which concerns on one Embodiment and shows the relationship between the valve seat in a fully closed state, a valve body, and a rotating shaft. FIG. 7 is a cross-sectional view taken along the line AA of FIG. The block diagram which concerns on one Embodiment and shows the electrical structure of another rotation energizing means. The flowchart which concerns on one Embodiment and shows the content of rotation bias control. The time chart which shows the behavior of throttle opening, engine speed, and intake pressure at the time of engine deceleration according to one embodiment. Sectional drawing which shows the relationship between a valve seat, a valve body, a rotating shaft, etc. when it concerns on one Embodiment and opens from a fully closed state. The fragmentary sectional view which shows the relationship between the valve seat in a fully closed state, a valve body, a valve closing stopper, etc. concerning one Embodiment. FIG. 4 is a partial cross-sectional view illustrating a relationship among a valve seat, a valve body, a valve closing stopper, and the like when a minute valve is opened according to an embodiment. The fragmentary sectional view which shows the relationship between the valve seat in a fully closed state, a valve body, a valve closing stopper, etc. concerning another embodiment.

  Hereinafter, an embodiment in which a double eccentric valve of the present invention is embodied in an exhaust gas recirculation valve (EGR valve) of an exhaust gas recirculation device (EGR device) provided in an engine will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration diagram of a gasoline engine system of 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. Intake manifold 8 includes a surge tank 8 a and a plurality of branch passages 8 b that branch from surge tank 8 a to each cylinder of engine 1. The exhaust passage 3 is provided with a turbine 5b of the supercharger 5 and a first catalyst 9 and a second catalyst 10 arranged in series to purify the exhaust. 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 gasoline engine system includes an EGR device 21. This device 21 includes an EGR passage 22 for flowing a part of exhaust discharged from the engine 1 to the exhaust passage 3 as exhaust gas recirculation gas (EGR gas) to the intake passage 2 and returning it to each cylinder, and an EGR passage 22. An exhaust gas recirculation cooler (EGR cooler) 23 for cooling the EGR gas and an EGR valve 24 provided in an EGR passage 22 downstream from the EGR cooler 23 for adjusting the flow rate of the EGR gas are provided. The EGR passage 22 includes an inlet 22a and a plurality of outlets 22b. An EGR distribution pipe 25 having a plurality of outlets 22 b is provided on the downstream side of the EGR passage 22. The EGR distribution pipe 25 is provided in the branch passage 8 b of the intake manifold 8. In this embodiment, the inlet 22 a of the EGR passage 22 is connected between the two catalysts 9 and 10 in the exhaust passage 3. The plurality of outlets 22b of the EGR distribution pipe 25 communicate with each of the branch passages 8b. The plurality of outlets 22b communicate with the respective branch passages 8b in order to introduce EGR gas evenly into the respective cylinders through 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, a basic configuration of the electric EGR valve 24 including the double eccentric valve will be described below. FIG. 2 is a perspective view showing the EGR valve 24. The EGR valve 24 includes a valve unit 31 constituted by a double eccentric valve, a motor unit 32 incorporating a motor 42 (see FIG. 5), and a deceleration mechanism unit 33 incorporating a deceleration mechanism 43 (see FIG. 5). Prepare. The valve part 31 includes a pipe part 37 having a flow path 36 through which EGR gas flows. In the flow path 36, a valve seat 38, a valve body 39, and a distal end portion of the rotary shaft 40 are arranged. The rotating force of the motor 42 (see FIG. 5) is transmitted to the rotating shaft 40 via the speed reduction mechanism 43 (see FIG. 5). The EGR gas corresponds to an example of the fluid of the present invention.

  FIG. 3 is a partially cutaway perspective view of the valve portion 31 in the fully closed state in which the valve body 39 is disposed at the fully closed position where the valve body 39 is seated on the valve seat 38. FIG. 4 is a perspective view of the valve portion 31 in a fully opened state where the valve body 39 is farthest from the valve seat 38. As shown in FIGS. 3 and 4, a step 36 a is formed in the flow path 36, and a valve seat 38 is incorporated in the step 36 a. The valve seat 38 has an annular shape and has a valve hole 38a in the center. An annular seat surface 38b is formed at the edge of the valve hole 38a. The valve body 39 has a disk shape, and an annular seal surface 39a corresponding to the seat surface 38b is formed on the outer periphery thereof. The valve body 39 is fixed to the tip of the rotating shaft 40 and is rotated integrally with the rotating shaft 40. 3 and 4, the flow path 36 is divided into an upstream flow path 36A and a downstream flow path 36B with a valve seat 38 as a boundary. 3 and 4, the flow path 36 below the valve seat 38 indicates the upstream flow path 36A of the EGR gas flow, and the flow path 36 above the valve seat 38 is the downstream flow path of the EGR gas flow. 36B is shown. And the valve body 39 is arrange | positioned in the downstream flow path 36B. In this embodiment, the upstream flow path 36A is an “exhaust side” communicating with the exhaust passage 3 via the EGR passage 22, and the downstream flow path 36B is connected to the intake passage 2 (intake manifold 8) via the EGR passage 22. ) Leading to “intake side”.

  FIG. 5 is a plan view showing the EGR valve 24 in the fully closed state. As shown in FIG. 5, the EGR valve 24 includes a body 41, a motor 42, a speed reduction mechanism 43, and a return mechanism 44 in addition to the valve seat 38, the valve body 39 and the rotating shaft 40 as main components. The body 41 includes an aluminum valve housing 45 including a flow path 36 and a pipe portion 37, and a synthetic resin end frame 46 that closes an open end of the housing 45. The rotating shaft 40 and the valve body 39 are provided in the valve housing 45. That is, the rotating shaft 40 is provided with a pin 40a for attaching the valve body 39 to the tip thereof. The rotating shaft 40 has a distal end including the pin 40 a as a free end, and the distal end is disposed in the downstream flow path 36 </ b> B together with the valve body 39. In this embodiment, the valve body 39 and the tip of the rotary shaft 40 are disposed in the downstream flow path 36 </ b> B, and the valve body 39 is provided so as to be seated on the valve seat 38. The rotating shaft 40 has a base end portion 40b on the opposite side of the pin 40a, and is cantilevered by the valve housing 45 at the base end portion 40b. In addition, the base end portion 40 b of the rotating shaft 40 is rotatably supported by the valve housing 45 via two bearings arranged apart from each other, that is, a first bearing 47 and a second bearing 48. A rubber seal 61 is provided between the rotary shaft 40 and the valve housing 45 adjacent to the second bearing 48. The first bearing 47 and the second bearing 48 are each constituted by a ball bearing. The valve body 39 includes a protrusion 39b that protrudes upward (downstream flow path 36B) on its axis L2 (see FIG. 6), and a pin hole 39c is formed in the protrusion 39b. The valve body 39 is fixed to the rotating shaft 40 by press-fitting and welding a pin 40a into the pin hole 39c. In this embodiment, the rotating shaft 40 is cantilevered via the bearings 47 and 48 with respect to the valve housing 45 so that bearing backlash in the micron unit is allowed between the valve body 39 and the valve seat 38. It has become.

  In FIG. 5, the end frame 46 is fixed to the valve housing 45 by a plurality of clips (not shown). Inside the end frame 46, an opening degree sensor 49 that is disposed corresponding to the base end of the rotating shaft 40 and detects the opening degree (valve opening degree) of the valve body 39 is provided. A main gear 51 is fixed to the base end portion 40 b of the rotating shaft 40. A return spring 50 is provided between the main gear 51 and the valve housing 45 to urge the valve body 39 to rotate in the valve closing direction. As the urging force of the return spring 50, it is possible to assume about “100 kPa” that can be opposed to the differential pressure before and after the valve element 39 in the fully closed state is opened. The return spring 50 corresponds to an example of the rotation urging means of the present invention. A recess 51a is formed on the back side of the main gear 51, and the magnet 56 is accommodated in the recess 51a. The magnet 56 is pressed and fixed by a pressing plate 57 from above. Therefore, when the main gear 51 rotates integrally with the valve body 39 and the rotating shaft 40, the magnetic field of the magnet 56 changes, and the opening sensor 49 detects the change of the magnetic field as the valve opening. Yes.

  As shown in FIG. 5, the motor 42 is housed in a housing recess 45 a formed in the valve housing 45. The motor 42 is fixed to the valve housing 45 via the retaining plate 58 and the leaf spring 59 in the housing recess 45a. The motor 42 is drivingly connected to the rotary shaft 40 via the speed reduction mechanism 43 in order to open and close the valve body 39. That is, the motor gear 53 fixed on the output shaft (not shown) of the motor 42 is drivingly connected to the main gear 51 via the intermediate gear 52. The intermediate gear 52 includes a two-stage gear including a large diameter gear 52a and a small diameter gear 52b. The intermediate gear 52 is rotatably supported by the valve housing 45 via the pin shaft 54. A motor gear 53 is connected to the large diameter gear 52a, and a main gear 51 is connected to the small diameter gear 52b. In this embodiment, the gears 51 to 53 constitute the speed reduction mechanism 43. The main gear 51 and the intermediate gear 52 are formed of a resin material for weight reduction. A rubber gasket 60 is provided at the joint between the valve housing 45 and the end frame 46. The gasket 60 seals the inside of the motor unit 32 and the speed reduction mechanism unit 33 from the atmosphere.

  Therefore, as shown in FIG. 3, when the motor 42 operates and the motor gear 53 rotates from the fully closed state, the rotation is decelerated by the intermediate gear 52 and transmitted to the main gear 51. Thereby, the rotating shaft 40 and the valve body 39 are rotated against the urging force of the return spring 50, and the flow path 36 is opened. That is, the valve body 39 is opened. When the valve body 39 is closed, the motor 42 reverses the motor gear 53. Further, in order to hold the valve element 39 at a certain opening, a rotational force is generated in the motor 42 and the rotational force is transmitted to the rotary shaft 40 via the motor gear 53, the intermediate gear 52 and the main gear 51 as the holding force. . When this holding force is balanced with the urging force of the return spring 50, the valve body 39 is held at a certain opening.

  Here, in the fully closed state shown in FIG. 3, an intake negative pressure may act on the downstream flow path 36 </ b> B from the intake passage 2. For example, an intake negative pressure of about “−50 to −65 kPa” can be assumed as an example when the engine 1 is idling on a flat ground, and about “−60 to −85 kPa” is an example when the engine 1 is decelerated. Intake negative pressure can be assumed. In this case, the valve body 39 is pulled by the intake negative pressure and floats from the valve seat 38, and EGR gas leaks into the downstream flow path 36 </ b> B and flows into the intake passage 2, which may cause misfire or the like in the engine 1. In this embodiment, the lift of the valve body 39 is such that the rotary shaft 40 is supported by the valve housing 45 via two bearings 47 and 48, and the bearings 47 and 48 are structurally provided with bearing backlash in units of microns. It can happen by doing. Therefore, the EGR valve 24 is provided with a configuration for preventing the valve body 39 from being lifted by the action of the intake negative pressure when fully closed.

  FIG. 6 is a sectional view showing the relationship between the valve seat 38, the valve body 39, and the rotating shaft 40 in the fully closed state. In FIG. 6, the axis (main axis) L <b> 1 of the rotary shaft 40 is disposed away from the seal surface 39 a of the valve body 39 and is disposed away from the axis L <b> 2 of the valve body 39. Here, the axis (secondary axis L3) of the pin 40a of the rotating shaft 40 extends in parallel to the main axis L1 and is offset from the main axis L1 in the radial direction of the rotating shaft 40. The valve body 39 is a first side portion 39A (a part indicated by hatching (紗) in FIG. 6) with a virtual plane V1 extending in parallel with the direction in which the axis L2 of the valve body 39 extends from the main axis L1. ) And the second side portion 39B (the portion not shaded in FIG. 6). When the valve body 39 is rotated from the fully closed state to the valve opening direction (clockwise direction in FIG. 6) F1 around the main axis L1 of the rotating shaft 40, the first side portion 39A is in the upstream side flow. The second side 39B is rotated toward the channel 36A, and the second side 39B is rotated toward the downstream channel 36B. When the valve element 39 is closed from the open state to the fully closed state, the valve element 39 is rotated in the valve closing direction (counterclockwise in FIG. 6) opposite to the valve opening direction F1.

  Assuming the positional relationship among the valve seat 38, the valve body 39, and the rotary shaft 40, the valve seat 38 has a valve opening direction F1 with respect to the fully closed valve body 39, as shown in FIGS. Is provided with a valve closing stopper 65 for restricting the rotation toward the valve closing direction opposite to the above. The valve closing stopper 65 is provided to be engageable with the upper surface of the first side portion 39A of the valve body 39. The valve closing stopper 65 has an L shape, and its short side portion 65a is fixed to the upper surface of the valve seat 38, and the long side portion 65b is disposed so as to be engageable with the upper surface of the first side portion 39A. Here, the valve closing stopper 65 can be fixed to the valve seat 38 by welding, for example. FIG. 7 shows the valve seat 38, the valve body 39, and the like by a cross-sectional view taken along line AA of FIG. As shown in FIGS. 6 and 7, a convex portion 65 c having a hemispherical convex curved surface is integrally formed at the engaging portion of the valve closing stopper 65 with the first side portion 39 </ b> A. In this embodiment, when the valve body 39 is in the fully closed state, the return spring 50 urges the valve body 39 to rotate in the valve closing direction, so that the upper surface of the first side portion 39A becomes the valve closing stopper 65. It engages with the convex portion 65c.

  Further, in this embodiment, in addition to the return spring 50, another rotation urging means for further urging the fully closed valve body 39 in the valve closing direction is provided. FIG. 8 is a block diagram showing the electrical configuration of the rotation urging means. As shown in FIG. 8, in this embodiment, a controller 70 for controlling the opening and closing of the EGR valve 24 and a throttle sensor 71 for detecting the opening (throttle opening) TA of the throttle valve 7a (see FIG. 1). ), An intake pressure sensor 72 (see FIG. 1) for detecting the intake pressure PM in the surge tank 8a, and an atmospheric pressure sensor 73 for detecting the atmospheric pressure PA. A throttle sensor 71, an intake pressure sensor 72, an atmospheric pressure sensor 73, and an EGR valve 24 are connected to the controller 70. Then, the controller 70 performs the following rotation urging control on the EGR valve 24. In this embodiment, the motor 42, the speed reduction mechanism 43, the controller 70, and the like of the EGR valve 24 correspond to an example of another rotation urging unit of the present invention.

  FIG. 9 is a flowchart showing the contents of the rotation bias control. When the process proceeds to this routine, the controller 70 takes in the throttle opening TA based on the detection value of the throttle sensor 71 in step 100.

  Next, in step 110, the controller 70 determines whether or not the deceleration EGR fully closed control is being performed. The controller 70 can make this determination based on the content of the previous opening / closing control of the EGR valve 24 and the throttle opening degree TA. If the determination result is affirmative, the controller 70 proceeds to step 120. If the determination result is negative, the controller 70 proceeds to step 190.

  In Step 120, the controller 70 determines whether or not the fully closed duty up flag XDTU is “0”. The flag XDTU is set to “1” when the fully closed duty up control described later is stopped, and set to “0” when the execution of the control is allowed. If this determination result is affirmative, the controller 70 proceeds to step 130, and if this determination result is negative, the controller 70 proceeds to step 180.

  In step 130, the controller 70 executes fully closed duty up control. In this control, when the valve body 39 is in the fully closed state for the EGR valve 24, the motor 42 is duty-controlled in order to further bias the valve body 39 in the valve closing direction in addition to the biasing force of the return spring 50. It is to be. Since the motor 42 is duty-controlled, the valve body 39 is urged to rotate in the valve closing direction, and high-frequency vibration is applied.

  Next, in step 140, the controller 70 takes in the intake pressure PM and the atmospheric pressure PA based on the detection values of the intake pressure sensor 72 and the atmospheric pressure sensor 73.

  Next, in step 150, the controller 70 calculates the intake negative pressure MPE by subtracting the atmospheric pressure PA from the intake pressure PM.

  Next, in step 160, the controller 70 determines whether or not the intake negative pressure MPE is smaller than a predetermined value P1. The predetermined value P1 means a reference value for determining a high negative pressure at which the fully closed duty up control is to be executed. That is, the high negative pressure means a negative pressure larger than the predetermined value P1. As this predetermined value P1, for example, “−80 kPa” can be applied. If this determination result is affirmative, the controller 70 returns the process to step 100, and if this determination result is negative, the controller 70 proceeds to step 170.

  In step 170, since the intake negative pressure MPE is not a high negative pressure, the controller 70 sets the fully closed duty up flag XDTU to “1” in order to stop the fully closed duty up control, and the process proceeds to step 100. return.

  On the other hand, in step 180 after shifting from step 120, the controller 70 stops the fully closed duty up control and returns the process to step 100.

  In Step 190 after shifting from Step 110, the controller 70 executes normal opening / closing control for the EGR valve 24.

  Next, in step 200, the controller 70 sets the fully closed duty up flag XDTU to “0” and returns the process to step 100.

  According to the rotation urging control, the controller 70 causes the valve body 39 to be fully closed for the EGR valve 24, and the intake negative pressure MPE having a high negative pressure greater than the predetermined value P1 is applied to the downstream flow path 36B. When operating, the fully closed duty up control is executed so as to further urge the valve body 39 in the valve closing direction. In this control, since there is a concern about the response delay of the rotation bias control when the engine 1 is decelerated, the controller 70 uniformly executes the fully-closed duty up control during the deceleration EGR fully-closed control. The control is released according to the change in the pressure MPE.

  FIG. 10 is a time chart showing the behavior of the throttle opening degree TA, the engine speed NE, and the intake pressure PM when the engine 1 is decelerated. In FIG. 10, when the throttle opening degree TA decreases rapidly between times t1 and t2 and the engine 1 starts decelerating, the engine speed NE starts to decrease and reaches the idle speed at time t3. At this time, the intake pressure PM starts to decrease between times t1 and t2, and becomes lower than the atmospheric pressure PA. After that, the intake pressure PM once decreases to a high negative pressure of about “−85 kPa” after the time t2, but thereafter, the intake pressure PM is about “−70 kPa” at the time t4 when the idle rotation speed of the engine 1 starts to stabilize. After returning to the negative pressure state, the degree of the negative pressure becomes constant with idle operation. The degree of the negative pressure that becomes constant decreases as the vehicle moves to a high altitude, the electric load of the vehicle increases, or the outside air decreases in temperature. Therefore, in this embodiment, the fully closed duty up control is executed only when the intake negative pressure MPE becomes a high negative pressure smaller than “−80 kPa” in order to further bias the valve body 39 in the valve closing direction. It has become so.

  According to the EGR valve 24 including the double eccentric valve of this embodiment described above, the fully closed valve body 39 seated on the valve seat 38 is urged to rotate by the return spring 50 in the valve closing direction. Since the first side portion 39A of the valve body 39 engages with the valve closing stopper 65, further rotation in the valve closing direction is restricted, and the fully closed state is maintained. At this time, the valve body 39 is urged to rotate in the valve closing direction with the first engagement portion E1 of the first side portion 39A of the first side portion 39A and the valve closing stopper 65 as a fulcrum, so that the valve body 39 is finely moved. The sealing surface 39a contacts the seat surface 38b of the valve seat 38. Further, even if the intake negative pressure acts on the downstream flow path 36B and the fully closed valve body 39 is pulled by the intake negative pressure, the first side portion 39A of the valve body 39 is engaged with the valve closing stopper 65. Therefore, the lift of the valve body 39 from the valve seat 38 is restricted. For this reason, when fully closed, the space between the valve body 39 and the valve seat 38 can be sealed, and EGR gas leakage can be suppressed. As a result, it is possible to prevent the EGR gas from leaking into the intake passage 2 and causing misfire or the like in the engine 1.

  Here, when the engine 1 is decelerating or idling, the intake negative pressure acting on the EGR valve 24 becomes smaller as the operating environment of the engine 1 becomes higher (the higher the sea level), and becomes the highest on flat ground. For this reason, if it can cope with the intake negative pressure on the flat ground, the countermeasure on the high ground will not be a problem. The urging force of the return spring 50 can keep the valve body 39 in a fully closed state corresponding to up to “100 kPa” as the differential pressure across the valve body 39. Accordingly, the intake negative pressure on the flat ground is normally “−60 to −85 kPa” during the deceleration operation of the engine 1 and “−50 to −65 kPa” during the idle operation. Even if not, the valve body 39 can be kept in the fully closed state against the intake negative pressure. On the other hand, when the engine 1 is supercharged, the supercharging pressure acting on the EGR valve 24 acts in the direction in which the valve body 39 is seated on the valve seat 38, so there is no problem with keeping the valve body 39 in a fully closed state. . Further, since the vibration of the engine 1 transmitted to the EGR valve 24 increases as the supercharging pressure increases, the valve seat 38 and the valve body 39 are superior to vibration resistance wear when fully closed.

  In addition, according to the configuration of this embodiment, when the intake negative pressure having a high negative pressure larger than the predetermined value P1 is applied to the downstream flow path 36B when fully closed (for example, at the early stage of deceleration of the engine 1), By the rotation urging control by the controller 70, the valve body 39 is further urged to rotate in the valve closing direction. Accordingly, even when a high negative intake air pressure acts on the valve body 39 when fully closed, the valve body 39 is prevented from being lifted from the valve seat 38, the valve body 39 is finely moved, and the sealing surface 39a is It contacts the seat surface 38b of the seat 38. For this reason, there is some variation in the urging force of the return spring 50, and even when a high negative pressure greater than the predetermined value P1 acts on the valve body 39 when fully closed, the gap between the valve body 39 and the valve seat 38 is ensured. The EGR gas leakage can be effectively suppressed. As a result, it is possible to prevent the EGR gas from leaking into the intake passage 2 and causing misfire or the like in the engine 1. Since this rotation bias control is only performed at the early stage of deceleration of the engine 1, the fuel consumption of the engine 1 is hardly deteriorated by energizing the motor 42 in this control.

  On the other hand, according to the configuration of this embodiment, when the intake negative pressure acts on the downstream flow path 36B and the valve element 39 is opened from the fully closed state, as shown in the sectional view of FIG. The valve body 39 is pulled by the intake negative pressure MPE, and the first side portion 39A starts to open while being engaged with the valve closing stopper 65 at the first engagement portion E1. For this reason, even if intake negative pressure acts on the valve body 39 when the valve is opened from the fully closed state, vibration of the valve body 39 can be suppressed, and thereby contact wear between the valve body 39 and the valve seat 38 can be suppressed. The EGR gas flow rate characteristics can be stabilized. In particular, in this embodiment, as shown in FIG. 11, in addition to the first engagement portion E1 between the first side portion 39A and the valve closing stopper 65, the outer periphery of the rotary shaft 40 is the inner periphery of the bearings 47 and 48. The valve element 39 starts to open in a state of being engaged by the second engaging portion E2 at the upper part of 47a, 48a, that is, in a state of being engaged at two locations. In this sense, the vibration of the valve body 39 can be effectively suppressed, whereby the contact wear between the valve body 39 and the valve seat 38 can be effectively suppressed, and the EGR gas flow rate characteristic can be further stabilized. it can.

  According to the configuration of this embodiment, since the first engagement portion E1 with the first side portion 39A of the valve closing stopper 65 forms the convex curved surface of the convex portion 65c, in the minute valve opening region of the valve body 39, The valve element 39 starts to open while the engaging portion E1 moves along the convex curved surface. That is, in the fully closed state, as shown in FIG. 12, the first side portion 39A of the valve body 39 and the convex portion 65c of the valve closing stopper 65 are engaged by the first engaging portion E1. Thereafter, when the valve body 39 is slightly opened, the first engaging portion E1 moves to the left in FIG. 13 as shown in FIG. For this reason, while being able to disperse | distribute the load of the 1st engaging part E1 of the valve body 39 and the valve closing stopper 65, the valve opening of the valve body 39 can be started smoothly. Even when the valve body 39 is pulled by the negative intake pressure in such a state, the valve body 39 is in contact with the first engagement portion E1 and the second engagement portion E2 (the outer periphery of the rotating shaft 40). The position of the valve body 39 can be stabilized without variation by being supported at two places (engagement portions with the inner circumferences 47a, 48a of the bearings 47, 48).

  Further, according to the configuration of this embodiment, the valve body 39 and the distal end portion of the rotating shaft 40 are disposed in the downstream flow path 36 </ b> B, and the valve body 39 is provided so as to be seated on the valve seat 38. Therefore, when fully closed, the supercharging pressure acting on the downstream flow path 36B acts in the direction in which the valve body 39 is seated on the valve seat 38. For this reason, when fully closed, the EGR valve 24 can be more reliably sealed using the supercharging pressure, and intake leakage from the valve 24 to the exhaust passage 3 can be effectively prevented.

  In addition, according to the configuration of this embodiment, the distal end portion of the valve body 39 and the rotary shaft 40 is disposed in the downstream side flow path 36B, and therefore the distal end portion of the valve body 39 and the rotary shaft 40 is EGR when fully closed. There is no exposure to gas. In this sense, it is possible to suppress deposits and adhesion of moisture at the distal end portions of the valve body 39 and the rotating shaft 40.

  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, as shown in FIG. 6, the valve closing stopper 65 is provided with a convex portion 65 c having a convex curved surface, and is configured to engage with the first side portion 39 </ b> A of the valve body 39. As shown in a sectional view in FIG. 14, the first side portion 39 </ b> A of the valve body 39 may be provided with a convex portion 39 d having a convex curved surface so as to be engaged with the valve closing stopper 65. Also in this case, the same operations and effects as those of the above embodiment can be obtained.

  (2) In the above embodiment, the controller 70 controls the EGR valve 24 to control the valve only when the valve element 39 is fully closed and a high negative pressure larger than the predetermined value P1 is applied to the downstream flow path 36B. The body 39 is further urged to rotate in the valve closing direction. On the other hand, whenever the valve body is in the fully closed state, the controller can be configured to control the EGR valve to further urge the valve body in the valve closing direction.

  (3) In the above-described embodiment, the double eccentric valve of the present invention is embodied as the EGR valve 24. However, the present invention is not limited to the EGR valve, and may be applied to various flow control valves as long as the flow rate of the fluid is adjusted. A double eccentric valve can be embodied.

The present invention can be used, for example, for an EGR valve of an EGR device mounted on an engine.

36 Flow path 36A Upstream flow path 36B Downstream flow path 38 Valve seat 38a Valve hole 38b Seat surface 39 Valve element 39A First side 39B Second side 39a Seal surface 40 Rotating shaft 42 Motor (another rotation) Energizing means)
43 Deceleration mechanism (another rotation urging means)
45 Valve housing 47 First bearing 48 Second bearing 50 Return spring (rotating biasing means)
65 Valve closing stopper 65c Convex part 70 Controller (another rotation urging means)
L1 axis (main axis)
L2 axis (valve)
V1 Virtual plane F1 Valve opening direction E1 First engagement portion

Claims (3)

A valve seat having an annular shape and including a valve hole and an annular seat surface formed in the valve hole;
A disc having a disc shape and an annular sealing surface corresponding to the seat surface formed on the outer periphery;
A housing including a flow path through which fluid flows;
The valve seat and the valve body are disposed in the flow path;
The flow path is divided into an upstream flow path and a downstream flow path with the valve seat as a boundary, and the valve element is disposed in the downstream flow path;
A rotating shaft for rotating the valve body;
A bearing for rotatably supporting the rotating shaft in the housing;
The axis of the rotary shaft is disposed away from the sealing surface of the valve body, and is disposed away from the axis of the valve body;
The valve body includes a first side and a second side with a virtual plane extending in parallel with a direction in which the axis of the valve body extends from the axis of the rotation shaft as a boundary, and the valve body includes the valve seat. When the first side part is rotated toward the upstream flow path and the second side part is directed toward the downstream flow path when rotating in the valve opening direction from the fully closed state seated on A double eccentric valve with rotating
A valve closing stopper provided to be engageable with the first side portion in order to restrict rotation of the valve body in the fully closed state in a valve closing direction opposite to the valve opening direction. When,
A double eccentric valve comprising: a rotation urging means for urging and urging the valve body in the fully closed state in the valve closing direction.   The engagement portion of the valve closing stopper with the first side portion or the engagement portion of the first side portion with the valve closing stopper forms a convex curved surface. Heavy eccentric valve.   When the valve body is in the fully closed state and a high negative pressure fluid acts on the downstream side flow path, the valve body is provided with another rotation for further biasing the valve body in the valve closing direction. The double eccentric valve according to claim 1 or 2, further comprising a biasing means.

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