JP3715161B2 - Engine exhaust valve device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionEngine exhaust valve device for selectively switching engine exhaust gas to main exhaust gas passage and bypass exhaust gas passage having HC adsorbent, especially leading to each upstream end of main exhaust gas passage and bypass exhaust gas passageValve body,Inside the valve bodyA valve shaft that crosses the valve shaft, a valve body that is attached to the valve shaft within the valve body, and a bottomed cylindrical first member that is provided between the valve shaft and the valve body by fitting one end of the valve shaft in a rotatable manner. A sliding bearing, and a cylindrical second sliding bearing provided between the valve shaft and the valve body with the other end side of the valve shaft pivotably inserted, and the valve shaft protruding from the second sliding bearing. The present invention relates to an exhaust gas valve device for an engine in which an actuator for rotationally driving the valve shaft is connected to the other end.
[0002]
[Prior art]
    Conventionally, such an exhaust gas valve device is already known, for example, in JP-A-11-166428.
[0003]
[Problems to be solved by the invention]
  In such an exhaust gas valve device, one end of the valve shaft is supported by the valve body via a first sliding bearing having a bottomed cylindrical shape, so that exhaust gas leakage from between the valve shaft and the first sliding bearing is prevented. Although there is no worry, the other end of the valve shaft passes through the second slide bearing, so there is a risk of exhaust gas leakage between the valve shaft and the second slide bearing. A seal ring is provided between them to prevent leakage of exhaust gas to the outside.
[0004]
  However, with the above-described countermeasure against leakage by the seal ring or the like, it is difficult to suppress external leakage to almost “0” over a long period of time while ensuring the operation reliability of the valve shaft, that is, the valve body. In particular, exhaust gas valve devices used in exhaust gas purification devices for vehicle engines comply with increasingly strict exhaust gas regulations, for example, the exhaust gas leak is almost "0" regardless of whether the vehicle runs for 120K or 150K miles for a long time. However, the conventional exhaust gas valve device cannot meet such a demand.
[0005]
  The present invention has been made in view of such circumstances, and it has been made possible to reduce the exhaust gas leak to almost "0" over a long period of time while ensuring the operation reliability of the valve shaft with a simple structure. An object is to provide a valve device.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, the invention according to claim 1An exhaust gas valve device for an engine that selectively switches engine exhaust gas to a main exhaust gas passage and a bypass exhaust gas passage having an HC adsorbent, and communicates with upstream ends of the main exhaust gas passage and the bypass exhaust gas passage.Valve body,Inside the valve bodyA valve shaft that crosses the valve shaft, a valve body that is attached to the valve shaft within the valve body, and a bottomed cylindrical first member that is provided between the valve shaft and the valve body by fitting one end of the valve shaft in a rotatable manner. A sliding bearing, and a cylindrical second sliding bearing provided between the valve shaft and the valve body with the other end side of the valve shaft pivotably inserted, and the valve shaft protruding from the second sliding bearing. An actuator that rotationally drives the valve shaft is connected to the other end.thingThe exhaust gas reservoir for storing exhaust gas leaking from between the valve shaft and the second slide bearing is formed between the second slide bearing and the valve shaft or between the second slide bearing and the valve body.AndA sealing means is provided between the second sliding bearing or the valve body and the valve shaft outside the exhaust gas reservoir along the axial direction of the valve shaft.The actuator is a negative pressure actuator that operates using a negative pressure generated in the intake system of the engine as a power source, and the exhaust gas reservoir is connected to a negative pressure conduit connecting the negative pressure actuator and the intake system.It is characterized by that.
[0007]
  According to such a configuration, the exhaust gas leaking between the valve shaft and the second sliding bearing from the exhaust gas flow passage is temporarily stored in the exhaust gas reservoir, and the gas suction means(That is, a negative pressure conduit connecting the negative pressure actuator and the intake system)From the exhaust gas poolIn the intake systemSince it is sucked, the leakage of the exhaust gas to the outside is almost suppressed to “0”. As a result, the sealing means arranged outside the exhaust gas reservoir only needs to fulfill the function of suppressing the suction of air from the outside to the exhaust gas reservoir, and is required to have a sealing property that affects the operation of the valve shaft. Therefore, it is sufficient if it has a simple structure. Even if the sealing means deteriorates due to long-term use, the exhaust gas does not leak to the outside. In addition, the inner diameter of the second sliding bearing need not be set strictly in consideration of the exhaust gas leak. That is, a simple structure in which the gas suction means is simply connected to the exhaust gas reservoir formed between the second slide bearing and the valve shaft or between the second slide bearing and the valve body, while ensuring the operation reliability of the valve shaft. It is possible to suppress this leakage to almost “0” over a long period of time.Further, the exhaust gas leaking between the second slide bearing and the valve shaft is returned to the intake system of the engine, so that the number of parts for constituting the gas suction means can be reduced, and the exhaust gas reservoir is located at a position close to the exhaust gas reservoir. The increase in the number of parts can be further suppressed by sharing the negative pressure conduit of the negative pressure actuator arranged with the gas suction means.
[0008]
  And claims2The invention of claim 11In addition to the configuration of the invention described above, the first and second sliding bearings are separated from the valve body while surrounding an outer peripheral surface of the valve shaft.Of exhaust gas insideThe overhanging cylinder portion that projects to the flow passage side is provided integrally, and according to such a configuration, even if the rust generated on the inner surface of the valve body falls, the rust is caused by the first and second sliding bearings and the valve. It is possible to prevent the valve shaft from being adversely affected by being caught between the shafts and to ensure the operation of the valve shaft more reliably.
[0009]
  Further claims3The invention of claim 11 orIn addition to the configuration of the invention described in 2,The conduit connecting the negative pressure conduit and the exhaust gas reservoir is provided with a check valve that allows only the flow from the exhaust gas reservoir to the intake system side. According to this configuration, the check valve opens so as to allow only the flow to the intake system side when the intake negative pressure in the intake system is equal to or greater than a predetermined value, and the flow of air from the intake system to the exhaust gas reservoir side Therefore, the backflow of the intake air can be prevented while eliminating the need for an electrically controlled valve or the like, and the exhaust gas leaking into the exhaust gas reservoir can be prevented only when the intake negative pressure is a predetermined value or more. It is possible to effectively recirculate to the intake system.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings. 1 to 4 show a first embodiment of the present invention. FIG. 1 is a schematic view showing an intake system and an exhaust system of an engine, FIG. 2 is a longitudinal sectional view of an exhaust gas valve device, and FIG. FIG. 4 is a sectional view taken along the line 3-3 in FIG.
[0011]
  First, in FIG. 1, an intake system 11 of a multi-cylinder engine E includes an intake pipe 12 having an upstream end connected to an air cleaner (not shown), a surge tank 13 connected to the downstream end of the intake pipe 12, and the intake air of each cylinder. An intake manifold 15 that connects the port 14 and the surge tank 13 is provided, and a fuel injection valve 16 is attached in the vicinity of the intake port 14 of the intake manifold 15. A bypass pipe 18 is connected to the intake pipe 12 so as to bypass the throttle valve 17 provided in the intake pipe 12, and an air control valve 19 is provided in the bypass pipe 18.
[0012]
  The exhaust system 20 of the engine E includes an exhaust manifold 22 whose upstream end is connected to an exhaust port 21 of each cylinder, a first exhaust pipe 23 commonly connected to the downstream end of the exhaust manifold 22, and a first exhaust pipe 23. A catalytic converter 24 connected to the downstream end of the catalyst, a second exhaust pipe 25 that forms a main exhaust passage 27 that can guide the exhaust gas that has passed through the catalytic converter 24, and a bypass exhaust passage 28 that is in parallel with the main exhaust passage 27. In addition, an exhaust gas case 26 that contains an HC adsorbent 29 and covers the second exhaust pipe 25, and an exhaust gas valve device that selectively switches the exhaust gas from the catalytic converter 24 to the main exhaust gas passage 27 and the bypass exhaust gas passage 28. 30A, and the exhaust gas flowing through the main exhaust gas passage 27 and the bypass exhaust gas passage 28 is connected to an exhaust muffler (not shown). It is discharged to the outside Te.
[0013]
  The HC adsorbent 29 is disposed at the intermediate portion of the bypass exhaust gas passage 28 so that the inner and outer periphery are supported by the outer surface of the intermediate portion of the second exhaust pipe 25 and the inner surface of the intermediate portion of the exhaust gas case 26. The exhaust gas introduced into the exhaust gas passage 28 flows through the HC adsorbent 29. Further, the second exhaust pipe 25 is provided with a plurality of communication holes 31, 31... Communicating with the downstream end of the bypass exhaust gas passage 28 on the downstream side of the arrangement position of the HC adsorbent 29. Excess exhaust gas flows from the communication holes 31, 31... To the exhaust muffler side through the downstream end of the main exhaust gas passage 27.
[0014]
  The HC adsorbent 29 is, for example, a crystalline aluminosilicate, specifically a mixture of ZSM-5 zeolite and a catalyst element. When the temperature of the exhaust gas is in a low temperature state of, for example, less than 100 ° C., the unburned HC component in the exhaust gas is removed. It adsorbs and desorbs the adsorbed unburned HC component at 100 ° C to 250 ° C. The unburned HC component adsorption / desorption temperature varies depending on the HC component.
[0015]
  The unburned HC component desorbed from the HC adsorbent 29 is returned to the intake system 11 between the bypass exhaust gas passage 28 upstream of the HC adsorbent 29 and the downstream side of the throttle valve 17 of the intake system 11. A pipe 32 is provided, and a return control valve 33 is provided in the middle of the return pipe 32. The return control valve 33 opens after reaching the temperature at which the HC adsorbent 29 desorbs the unburned HC component after the engine E is started. .
[0016]
  In the exhaust gas valve device 30A, the unburned HC component is discharged to the outside due to the fact that the catalyst in the catalytic converter 24 has not reached the activation temperature until the predetermined time has elapsed after the engine E is started. In order to prevent this, the exhaust gas from the catalytic converter 24 is guided to the bypass exhaust gas passage 28, and the exhaust gas flow is switched so that the exhaust gas from the catalytic converter 24 is guided to the main exhaust gas passage 27 after the predetermined time has elapsed. .
[0017]
  2 to 4, the exhaust gas valve device 30 </ b> A is attached to the valve shaft 35 within the valve body 34, a valve body 34 made of cast iron material, a valve shaft 35 that is rotatably supported by the valve body 34. Valve bodies 36 and 37 to be provided.
[0018]
  The valve body 34 is branched from an intermediate portion of the main flow passage 38 and a main flow passage 38 that passes the upstream end to the downstream end of the catalytic converter 24 and passes the downstream end to the upstream end of the main exhaust gas passage 27. A bypass flow passage 39 communicating with the upstream end of the bypass exhaust gas passage 28 is formed, and an upstream flange portion 40 provided integrally with the valve body 34 so as to open the upstream end of the main exhaust gas passage 38 is a catalyst. Fastened to the converter 24, the downstream end portions of the main exhaust gas passage 38 and the bypass exhaust gas passage 39 are opened independently of each other, and the downstream flange portion 41 provided in the valve body 34 is fastened to the second exhaust pipe 25 and the exhaust gas case 26. Is done.
[0019]
  An annular valve seat 42 is provided on the inner surface of the valve body 34 in the middle of the main flow passage 38 on the downstream side of the branch position of the bypass flow passage 39, and the valve body 36 has a peripheral portion on the valve seat 42. It is formed in a disk shape so as to be seated and to block the main flow passage 38. The valve body 34 is provided with an annular valve seat 43 at an opening position to the main flow passage 38 at the upstream end of the bypass flow passage 39, and the valve body 37 has a peripheral edge seated on the valve seat 43. It is formed in a disc shape so as to block the bypass flow passage 39. In addition, both valve bodies 36 and 37 are in a state in which the valve body 37 opens the bypass flow path 39 in a state where the main flow path 38 is blocked by the valve body 36, and the valve body 37 blocks the bypass flow path 39. In the state, the valve bodies 36 are connected to each other by the connecting member 44 so as to open the main flow passage 38.
[0020]
  A concave portion 39 a that is recessed toward the main flow passage 38 is formed at the upstream end of the bypass flow passage 39, and the valve shaft 35 is disposed so as to cross the concave portion 39 a of the bypass flow passage 39 and is fastened to the valve shaft 35. The valve body 37 is fastened to the arm 45 to be operated. As a result, the valve bodies 36 and 37 rotate around the axis of the valve shaft 35 in response to the rotation of the valve shaft 35, and the valve body 37 blocks the main flow passage 38 and the valve body 37 passes the bypass flow passage 39. The open state and the state in which the valve body 37 blocks the bypass flow passage 39 and the valve body 36 opens the main flow passage 38 are alternatively switched.
[0021]
  In the valve body 34 corresponding to the valve shaft 35, support holes 46 and 47 extending between the inside and the outside of the valve body 34 are provided coaxially with the valve shaft 35, and these support holes 46 and 47 are bypassed. Large-diameter holes 46b and 47b are coaxially connected to the small-diameter holes 46a and 47a on the flow passage 39 side with a step.
[0022]
  A bottomed cylindrical first sliding bearing 48 having a closed outer end is fitted and fixed to the large-diameter hole portion 46b of the support hole 46, and a cylindrical second slide is formed in the large-diameter hole portion 47b of the support hole 47. The bearing 49A is fitted and fixed. One end of the valve shaft 35 is rotatably fitted to the first sliding bearing 48, and the other end of the valve shaft 35 penetrates the second sliding bearing 49A so as to be rotatable. In addition, the double slide bearings 48 and 49A extend from the inner surface of the valve body 34 to the bypass flow passage 39 side through the small diameter holes 46a and 47a of the support holes 46 and 47 while surrounding the valve shaft 35. The parts 50 and 51 are provided integrally.
[0023]
  In the second slide bearing 49A, a small-diameter hole 52, a medium-diameter hole 53 larger in diameter than the small-diameter hole 52, and a large-diameter hole 54 larger in diameter than the medium-diameter hole 53 are coaxially arranged in this order from the bypass flow passage 39 side. And penetrates through the second sliding bearing 49A.Valve stemAn intermediate portion 35 is provided with a flange portion 35 a that opposes the outer peripheral surface to the inner surface of the medium diameter hole 53.
[0024]
  The other end of the valve shaft 35 protrudes outward from the second slide bearing 49A, and the other end of the valve shaft 35 has a disk shape that projects outward in the radial direction from the outer peripheral surface of the valve shaft 35. The link plate 55 is fixed. A coiled return spring 56 is provided between the link plate 55 and the valve body 34, and this return spring 56 is linked in a direction in which the valve body 37 is seated on the valve seat 43 and the bypass flow passage 39 is blocked. The plate 55 and the valve shaft 35 are urged to rotate.
[0025]
  Sealing means 57 is provided between the second sliding bearing 49A and the valve shaft 35 on the outer side of the flange 35a. The seal 57 is in contact with the outer surface side of the flange 35a and forms a medium diameter hole 53. A ring-shaped sealing member 58 to be inserted, a pressing member 59 formed in a ring shape so as to sandwich the sealing member 58 between the flange portions 35a, and inserted into the medium-diameter hole 53; Each of which has a plurality of packings 60 slidably contacting the outer surface of the valve shaft 35, and a seal press 85 that holds each packing 60 and is inserted into the large-diameter hole 54, and is sandwiched between the link plate 55 and the flange portion 35a. Is done.
[0026]
  In the sealing means 57, the outer surface of the sealing member 58 compressed in the axial direction is in sliding contact with the inner surface of the medium-diameter hole 53, and each packing 60 is in sliding contact with the outer surface of the valve shaft 35. The space between the second slide bearings 49A is sealed.
[0027]
  In addition, the link plate 55 is formed to have a sufficiently large diameter so as to cover the sealing means 57 from the outside, and as much as possible to prevent the valve shaft 35 and the sealing means 57 from being contaminated by muddy water or dust scattered as the vehicle travels. By avoiding this, the operation reliability of the valve shaft 35 can be ensured.
[0028]
  A connecting pin 61 is implanted in the link plate 55 at a position eccentric from the axis of the valve shaft 35, and a rod of a negative pressure actuator 62 that drives the valve shaft 35 to rotate against the spring force of the return spring 56. 63 is connected to the connecting pin 61.
[0029]
  The negative pressure actuator 62 includes a casing 64 and a diaphragm 67 whose peripheral portion is sandwiched between the casing 64 so as to partition the inside of the casing 64 into a negative pressure chamber 65 and an atmospheric pressure chamber 66. 64 is provided with a connecting pipe 68 communicating with the negative pressure chamber 65, and the rod 63 connected to the connecting pin 61 of the link plate 55 is connected to the central portion of the diaphragm 67 from the atmospheric pressure chamber 66 side.
[0030]
  Referring to FIG. 1, the connection pipe 68 and the downstream side of the throttle valve 17 in the intake system 11 are connected via a negative pressure conduit 69, and the engine E is in the middle of the negative pressure conduit 69. A negative pressure control valve 70 is provided that closes after a predetermined time has elapsed since the start. Therefore, when the negative pressure control valve 70 is opened, intake negative pressure is introduced into the negative pressure chamber 65, and the diaphragm 67 is bent toward the negative pressure chamber 65 so that the rod 63 rotates the link plate 55 in the axial direction. Will work. That is, the negative pressure actuator 62 operates using a negative pressure generated in the intake system 11 of the engine E as a power source, and operates until a predetermined time elapses after the engine E is started to open the bypass flow passage 39. Then, the valve shaft 35 is rotationally driven to a position where the main flow passage 38 is blocked.
[0031]
  The casing 64 of the negative pressure actuator 62 is supported by a support plate 71 fastened to the valve body 34. In addition, the support plate 71 is provided with a circular opening 72 in which the link plate 55 is disposed.
[0032]
  A support frame 73 is fastened to the support plate 71 so as to cover the link plate 55, and an opening degree sensor 74 is fixed to the support frame 73. The opening sensor 74 incorporates a detection plate 75 having a rotational axis coaxial with the valve shaft 35, and a detected shaft 76 provided on the link plate 55 at a position eccentric from the axis of the valve shaft 35. It is engaged with a protrusion 75 a provided on the outer periphery of the detection plate 75. As a result, the detection plate 75 rotates according to the rotation of the valve shaft 35, and the rotation position of the valve shaft 35 is detected by the opening sensor 74.
[0033]
  In addition, the support plate 71 covers the negative pressure actuator 62 and the opening sensor 74 from below so as to prevent pebbles and the like that have jumped as the vehicle travels from colliding with the negative pressure actuator 62 and the opening sensor 74. The cover 84 is fixed.
[0034]
  According to the present invention, the annular exhaust gas reservoir 77A for storing exhaust gas leaking from between the valve shaft 35 and the second slide bearing 49A is provided with an annular recess on the inner surface of the intermediate portion of the small diameter hole 52 in the second slide bearing 49A. Thus, the second slide bearing 49A and the valve shaft 35 are formed.
[0035]
  The gas accumulated in the exhaust gas reservoir 77A is sucked by the gas suction means 78A. The gas suction means 78A is configured by connecting an exhaust gas reservoir 77A to the intake system 11 downstream of the throttle valve 17, and includes a passage 79 provided in the second sliding bearing 49A through the exhaust gas reservoir 77A, A connection pipe 80 provided in the valve body 34 through the passage 79, a portion of the negative pressure conduit 69 closer to the intake system 11 than the negative pressure control valve 70, a conduit 81 connecting between the connection pipes 80, and a connection position of the conduit 81 The exhaust gas reservoir 77 </ b> A is connected to the intake system 11 through a negative pressure conduit 69 extending from the intake system 11 to the intake system 11. In addition, the connecting pipe 80 is provided with a throttle 82, and the conduit 81 is provided with a check valve 86. Thus, the check valve 86 is opened to allow only the flow to the intake system 11 when the intake negative pressure of the intake system 11 downstream of the throttle valve 17 is equal to or higher than a predetermined value. Is to block the flow of air from the exhaust gas to the exhaust gas reservoir 77A side. This makes it possible to prevent backflow of the intake air while eliminating the need for a valve or the like that is particularly electrically controlled, and exhaust gas leaking from between the valve shaft 35 and the second slide bearing 49A only when the intake negative pressure is greater than or equal to a predetermined value. Can be effectively recirculated to the intake system 11.
[0036]
  Next, the operation of the first embodiment will be described. In the exhaust gas valve device 30A, an exhaust gas reservoir 77A for storing exhaust gas leaking from between the valve shaft 35 and the second slide bearing 49A is replaced by the second slide bearing 49A and the valve shaft 35. A gas suction means 78A is connected to the exhaust gas reservoir 77A, and a sealing means 57 is provided between the valve shaft 35 and the valve body 34 outside the exhaust gas reservoir 77A along the axial direction of the valve shaft 35. It has been.
[0037]
  Therefore, the exhaust gas leaking from the bypass flow passage 39 through the valve shaft 35 and the second sliding bearing 49A is temporarily stored in the exhaust gas reservoir 77A and is sucked from the exhaust gas reservoir 77A by the gas suction means 78A. Leakage of the exhaust gas to the outside is almost suppressed to “0”. As a result, the sealing means 57 disposed outside the exhaust gas reservoir 77A only needs to fulfill the function of suppressing the suction of air from the outside to the exhaust gas reservoir 77A, and requires a sealing property that affects the operation of the valve shaft 35. Therefore, it is sufficient if it has a simple structure. Even if the sealing means 57 is deteriorated by long-term use, the exhaust gas does not leak to the outside. In addition, the inner diameter of the second slide bearing 49A need not be set strictly in consideration of the exhaust gas leak. That is, a simple structure in which the gas suction means 78A is simply connected to the exhaust gas reservoir 77A formed between the second sliding bearing 49A and the valve shaft 35, and long-term exhaust gas leakage is ensured while ensuring the operation reliability of the valve shaft 35. It becomes possible to suppress to almost “0” over the period.
[0038]
  Further, since the gas suction means 78A is constructed by connecting the intake system 11 of the engine E to the exhaust gas reservoir 77A, the exhaust gas leaking between the second sliding bearing 79A and the valve shaft 35 is returned to the intake system 11 of the engine E. Therefore, the number of parts for constituting the gas suction means 78A can be reduced.
[0039]
  Moreover, the negative pressure actuator 62 operates using a negative pressure generated in the intake system 11 of the engine E as a power source, and an exhaust gas reservoir 77A is connected to a negative pressure conduit 69 connecting the intake system 11 and the negative pressure actuator 62. Therefore, by sharing the negative pressure conduit 69 of the negative pressure actuator 62 disposed at a position close to the exhaust gas reservoir 77A with the gas suction means 78A, the increase in the number of parts can be further suppressed.
[0040]
  Further, the first and second sliding bearings 48 and 49A are integrally provided with overhanging cylindrical portions 50 and 51 that project from the valve body 34 toward the bypass flow passage 39 while surrounding the outer peripheral surface of the valve shaft 35. Even if the rust generated on the inner surface of the valve body 34 made of cast iron falls, the overhanging cylinder portions 50 and 51 allow the rust to be caught between the first and second sliding bearings 48 and 49A and the valve shaft 35. Therefore, it is possible to prevent the biting of rust from adversely affecting the rotational operation of the valve shaft 35 and to ensure the operation of the valve shaft 35 more reliably.
[0041]
  FIG. 5 shows a second embodiment of the present invention, and parts corresponding to the first embodiment are given the same reference numerals.
[0042]
  In the exhaust gas valve device 30B, a cylindrical second slide bearing 49B is fitted and fixed in a large-diameter hole portion 47b of a support hole 47 provided in the valve body 34, and the bearing 35 penetrating the second slide bearing 49A. A link plate 55 is fixed to the other end. In addition, the valve shaft 35 is provided with a flange 35a having an outer peripheral surface facing the inner surface of the large-diameter hole 47b in the support hole 47. The second slide bearing 49B and the valve body are disposed outside the flange 35a. 34 is provided with a sealing means 57.
[0043]
  An annular exhaust gas reservoir 77B for storing exhaust gas leaking from between the valve shaft 35 and the second slide bearing 49B is provided with an annular recess on the outer surface of the intermediate portion of the second slide bearing 49B, so that the second slide bearing 49B and the valve body are provided. 34 is formed between the flange 35a of the valve shaft 35 and the exhaust gas reservoir 77B, and leaks to the flange 35a side between the valve shaft 35 and the second slide bearing 49B on the outer surface of the second slide bearing 77B. Are provided with a plurality of communication grooves 83 for guiding the exhaust gas to the exhaust gas reservoir 77B.
[0044]
  The gas accumulated in the exhaust gas reservoir 77B is suctioned by the gas suction means 78B. The gas suction means 78B communicates with the exhaust gas reservoir 77A and is connected to a connecting pipe 80 provided in the valve body 34 and a negative pressure conduit 69 (see FIG. 1) and a conduit 81 (see FIG. 1) connecting the portion closer to the intake system 11 than the negative pressure control valve 70 and the connection pipe 80, and a negative pressure conduit 69 from the connection position of the conduit 81 to the intake system 11. The exhaust gas reservoir 77A is connected to the intake system 11 downstream of the throttle valve 17 via the.
[0045]
  According to the second embodiment, the same effect as that of the first embodiment can be obtained.
[0046]
  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is.
[0047]
【The invention's effect】
  As aboveBookAccording to the present invention, it is possible to suppress the leakage of exhaust gas to almost “0” over a long period of time while ensuring the operation reliability of the valve shaft.Further, the exhaust gas leaking between the second slide bearing and the valve shaft is returned to the intake system of the engine, so that the number of parts for constituting the gas suction means can be reduced, and the exhaust gas reservoir is located at a position close to the exhaust gas reservoir. The increase in the number of parts can be further suppressed by sharing the negative pressure conduit of the negative pressure actuator arranged with the gas suction means.
[0048]
  And especially claims2According to the invention, it is possible to prevent the rust from being caught between the first and second sliding bearings and the valve shaft and adversely affecting the rotational operation of the valve shaft, thereby ensuring the operation of the valve shaft more reliably. it can.
[0049]
  In particular, according to the invention of claim 3, the above-mentionedA check valve that allows only the flow from the exhaust gas reservoir to the intake system side is interposed in the conduit connecting the negative pressure conduit and the exhaust gas reservoir, and this check valve has an intake negative pressure of the intake system of a predetermined value. At the above time, the valve is opened so as to allow only the flow to the intake system side, and the flow of air from the intake system to the exhaust gas reservoir side can be shut off. Thus, the backflow of the intake air can be prevented, and the exhaust gas leaking between the second slide bearing and the valve shaft can be effectively recirculated to the intake system only when the negative intake pressure is equal to or higher than a predetermined value.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an intake system and an exhaust system of an engine.
FIG. 2 is a longitudinal sectional view of an exhaust gas valve device.
3 is a cross-sectional view taken along line 3-3 of FIG.
4 is a view taken in the direction of arrow 4 in FIG.
FIG. 5 is a cross-sectional view corresponding to FIG. 3 of the second embodiment.
[Explanation of symbols]
11 ... Intake system
20 ... Exhaust system
27 ... Main exhaust gas passage
29 ... HC adsorbent
28 ... Bypass exhaust gas passage
30A, 30B ... Exhaust gas valve device
34 ... Valve body
35 ... Valve stem
36, 37 ... Valve body
39: Bypass passage
48 ... first sliding bearing
49A, 49B ... second sliding bearing
50, 51 ... Overhang tube
57... Sealing means
62 ... Negative pressure actuator
69 ... Negative pressure conduit
77A, 77B ... exhaust gas reservoir
78A, 78B ... Gas suction means
81 ... Conduit
86 ... Check valve
E ... Engine

Claims (3)

An engine exhaust gas valve device for selectively switching engine exhaust gas to a main exhaust gas passage (27) and a bypass exhaust gas passage (28) having an HC adsorbent (29),
A main exhaust gas passage (27) and valve body leading to the upstream end of the bypass exhaust gas passage (28) (34), and its valve body (34) in the valve shaft transverse to (35), the valve shaft in the valve body (34) A bottomed cylinder provided between the valve shaft (35) and the valve body (34) by fitting the valve body (36, 37) attached to the (35) and one end of the valve shaft (35) in a rotatable manner. A cylindrical first sliding bearing (48) and a second cylindrical sliding provided between the valve shaft (35) and the valve body (34) through the other end of the valve shaft (35) so as to be rotatable. And an actuator (62) for rotating the valve shaft (35) is connected to the other end of the valve shaft (35) protruding from the second sliding bearing (49A, 49B). in those that,
An exhaust gas reservoir (77A, 77B) for storing exhaust gas leaking from between the valve shaft (35) and the second slide bearing (49A, 49B) is provided between the second slide bearing (49A) and the valve shaft (35) or the second slide. bearings (49B) and valve body (34) is formed between Rutotomoni, reservoir exhaust gas along the axial direction of the valve shaft (35) (77A, 77B) a second slide bearing (49A) at the outside than or valve body Sealing means (57) is provided between (34) and the valve stem (35) ;
The actuator is a negative pressure actuator (62) that operates using a negative pressure generated in the intake system (11) of the engine (E) as a power source, and between the negative pressure actuator (62) and the intake system (11). An exhaust gas valve device for an engine , wherein the exhaust gas reservoir (77A, 77B) is connected to a negative pressure conduit (69) connecting the two . An overhang cylinder that projects from the valve body (34) to the exhaust gas flow passage (39) side of the first and second sliding bearings (48; 49A, 49B) while surrounding the valve shaft (35). The exhaust gas valve device for an engine according to claim 1 , wherein the parts (50, 51) are provided integrally. Only the flow from the exhaust gas reservoir (77A, 77B) to the intake system (11) side is allowed to the conduit (81) connecting the negative pressure conduit (69) and the exhaust gas reservoir (77A, 77B). An exhaust valve device for an engine according to claim 1 or 2, characterized in that a check valve (86) is interposed .

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