JP4973549B2 - Exhaust device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust device for an internal combustion engine provided with a flow path switching valve.

  For the purpose of improving the exhaust performance of an internal combustion engine, a flow path switching valve that opens and closes an exhaust passage is provided, and when the valve is closed, for example, exhaust flows through a bypass passage. Thus, in the configuration in which the flow path switching valve is provided in the exhaust passage, since the high-temperature exhaust gas does not flow when the valve is closed, the temperature around the flow path switching valve is lowered, and moisture in the exhaust gas is condensed. Condensed water may be collected around the flow path switching valve. As a result, when the condensed water scatters and flows in the downstream direction when the flow path switching valve is opened, sensor components such as an air-fuel ratio sensor and a temperature sensor provided on the downstream side may be adversely affected.

Therefore, in Patent Document 1, a condensate water storage portion recessed downward in a cylindrical shape is provided around a valve seat portion on which a valve body of a flow path switching valve (control valve) is seated. And it is described that the condensed water generated when the valve is closed enters the storage part, and when the flow path switching valve is opened, the condensed water is not already attached to the valve body or the like.
JP, 2007-15496, A [0055] etc.

  However, according to research by the inventors, in particular, those with excellent sealing performance of the valve body, the temperature on the upstream side of the valve body did not rise when the valve was closed, and a considerable amount of condensed water adhered to the surface of the valve body, arm, etc. It has been found that the condensed water that has adhered may scatter and flow out when the valve body is opened, and may flow out to the downstream side of the valve body. In the above-mentioned conventional example, the scattering of condensed water when opening such a valve body is not considered.

  The present invention has been made in view of such problems. In other words, the exhaust system for an internal combustion engine of the present invention has a flow path switching valve that opens and closes a valve port through which exhaust flows from the vertical upper side to the vertical lower side, and the flow path switching valve is formed with the valve port. A valve housing, a rotary shaft rotatably supported by the valve housing, an arm extending in a radial direction from the rotary shaft, and a valve attached to a tip of the arm and seated on a seal surface surrounding the valve port when closed And having a body. In the valve housing, when the valve body is in an open posture in which the valve body rises upstream, a valve housing portion that houses the valve body, the arm, and the rotating shaft in the open posture is recessed in the port side wall portion of the valve port. In addition, a condensate reservoir is recessed at a position outside the flow path of the valve port and below the valve housing.

  When the valve is closed, the condensate generated upstream of the valve element is received by the reservoir, allowing the condensed water to gradually evaporate as the temperature rises. Even if the condensed water remaining due to adhering to the surface of the liquid flows out, the condensing part is recessed below the valve accommodating part accommodating the valve body, the arm and the rotating shaft in the open posture. Water can be received by the reservoir and can be prevented from flowing out to the valve port on the downstream side of the valve body.

  Hereinafter, an embodiment in which the present invention is applied as an exhaust system for an in-line four-cylinder internal combustion engine will be described in detail with reference to the drawings. Note that “upper” and “lower” used in the present specification basically means an upper direction and a lower direction in the vertical direction.

  FIG. 1 is an explanatory view schematically showing the intake / exhaust system of the internal combustion engine. First, the configuration of the exhaust system will be described with reference to FIG. In the cylinder head 1a of the internal combustion engine 1, exhaust ports 2 of cylinders # 1 to # 4 arranged in series are formed so as to open toward the side surfaces, respectively. In addition, the main passage 3 is connected. The four main passages 3 of the # 1 cylinder to the # 4 cylinder merge into one flow path, and the main catalytic converter 4 is disposed on the downstream side thereof. The main catalytic converter 4 has a large capacity arranged under the floor of the vehicle, and includes, for example, a three-way catalyst and an HC trap catalyst as the catalyst. The main passage 3 and the main catalytic converter 4 constitute a main passage through which exhaust flows during normal operation. In addition, a flow path switching valve 5 that opens and closes the main passages 3 at the same time is provided as a flow path switching means at the junction of the four main paths 3 from each cylinder. The flow path switching valve 5 is driven to open and close by an appropriate actuator 5a.

  On the other hand, bypass passages 7 each having a smaller passage sectional area than the main passage 3 are branched from the main passages 3 of the respective cylinders as bypass passages. The branch point 6 that is the upstream end of each bypass passage 7 is set to a position on the upstream side of the main passage 3 as much as possible. The four bypass passages 7 merge into one flow path on the downstream side, and a bypass catalytic converter 8 using a three-way catalyst is interposed immediately after the junction. The bypass catalytic converter 8 has a small capacity as compared with the main catalytic converter 4, and preferably uses a catalyst excellent in low-temperature activity. The downstream end of the bypass passage 7 extending from the outlet side of the bypass catalytic converter 8 is connected to the main passage 3 at a junction 12 upstream of the main catalytic converter 4 in the main passage 3 and downstream of the flow path switching valve 5. ing. Air-fuel ratio sensors 10, 11, 13, and 14 are arranged at the inlet and outlet of the main catalytic converter 4 and at the inlet and outlet of the bypass catalytic converter 8, respectively.

  The internal combustion engine 1 includes a spark plug 21, and a fuel injection valve 23 is disposed in the intake passage 22. Furthermore, a so-called electronically controlled throttle valve 24 that is opened and closed by an actuator such as a motor is disposed upstream of the intake passage 22, and an air flow meter 25 that detects the intake air amount is provided downstream of the air cleaner 26. Yes. Further, a swirl control valve 30 for generating a swirl in the cylinder is provided in the vicinity of the intake port of the intake passage 22. The swirl control valve 30 is opened and closed via an appropriate actuator (not shown). When the swirl control valve 30 is closed, a part of the passage section of the intake passage 22 is shielded to generate a swirl. The swirl control valve 30 may be of various known types such as a butterfly valve type having a notch in a part of a plate-like valve body, or a type that opens and closes one of a pair of intake ports. Can be used. In addition, a tumble control valve that generates a tumble flow in the cylinder may be used as the intake control valve.

  Various control parameters of the internal combustion engine 1, for example, the fuel injection amount by the fuel injection valve 23, the ignition timing by the spark plug 21, the opening degree of the throttle valve 24, the open / close state of the flow path switching valve 5 and the swirl control valve 30, etc. Is controlled by the engine control unit 27. In addition to the sensors described above, the engine control unit 27 includes various sensors such as a coolant temperature sensor 28 and an accelerator opening sensor 29 that detects the opening (depression amount) of an accelerator pedal operated by a driver. Detection signal is input.

  In such a configuration, when the engine temperature or the exhaust temperature after the cold start is low, the flow path switching valve 5 is closed via the actuator 5a, and the main passage 3 is blocked. Therefore, the entire amount of exhaust discharged from each cylinder flows from the branch point 6 to the bypass catalytic converter 8 through the bypass passage 7. The bypass catalytic converter 8 is located upstream of the exhaust system, that is, at a position close to the exhaust port 2 and is small in size, so that it is activated quickly and exhaust purification is started at an early stage.

  On the other hand, if the engine warm-up progresses and the engine temperature or the exhaust temperature becomes sufficiently high, it is considered that the catalyst of the main catalytic converter 4 is activated as one of the trigger conditions, and the flow path switching valve 5 is opened. The Thus, the exhaust discharged from each cylinder mainly passes through the main catalytic converter 4 from the main passage 3. At this time, the bypass passage 7 side is not particularly cut off, but the bypass passage 7 side has a smaller passage cross-sectional area than the main passage 3 side and the bypass catalytic converter 8 is interposed. Due to the difference, most of the exhaust flow passes through the main passage 3 side and hardly flows into the bypass passage 7 side. Therefore, the thermal deterioration of the bypass catalytic converter 8 is sufficiently suppressed.

  Next, the flow path switching valve 5, which is a main part of the present embodiment, will be described with reference to FIGS. In this embodiment, the flow path switching valves 5 for four cylinders are integrated as one valve unit. The flow path switching valve 5 is mainly composed of a valve housing 31 formed integrally by casting. The valve housing 31 is formed with four valve ports 32 corresponding to the respective cylinders. These valve ports 32 are respectively formed in openings in two rows, that is, at the positions where the vertices of the squares are formed. In the in-vehicle state, these valve ports 32 are arranged so as to be substantially along the vertical direction, and are set so that the exhaust gas flows from the upstream side on the vertically upper side to the downstream side on the vertically lower side.

  The valve bodies 36 open and close these valve ports 32 from the upstream side. In the middle of the valve port 32, the sealing surface 35 of the valve seat portion with which the outer peripheral edge of the valve body 36 contacts is machined. The sealing surface 35 has an inclined surface / tapered surface that gradually decreases in diameter from the upstream side toward the downstream side. As shown also in FIG. 5, the upper end of the sealing surface 35 of each valve port 32 is connected to the lower end of the upstream port upstream portion 33 that forms a straight line. The lower end of the sealing surface 35 having a reduced diameter is connected to the upper end of the downstream port downstream portion 37 extending linearly. That is, the protrusion shape is not such that the periphery of the seal surface 35 partially protrudes inward, and the port downstream portion 37 has a linear shape narrower than the port upstream portion 33 due to the reduced diameter of the seal surface 35. It is said. For this reason, the flow of the exhaust gas becomes smooth, and the periphery of the seal surface 35 becomes thick, the heat capacity increases, and the distortion around the seal surface 35 can be suppressed.

  The four valve ports 32 are arranged in parallel to each other while being gathered and close to each other, and the port side wall portion 38 around the valve port 32 is substantially at a central thick portion 39 surrounded by the four valve ports 32. It is continuous and intersects in a cross shape. The central thick portion 39 is formed with a central hole 40 so that the thickness of the port side wall portion 38 in the vicinity of the seal surface 35 is uniform, and the sealing performance due to the variation of the thermal strain in the circumferential direction. Is suppressed. The valve housing 31 is integrally casted with an upstream flange 41 of a predetermined thickness projecting in the radial direction. The upstream flange 41 is bolted to a mounting flange of an exhaust manifold (not shown) by a plurality of bolts. It is fixed with.

  The valve body 36 is attached to the tip of an arm 44 that swings together with the rotating shaft 43, and the outer peripheral edge thereof has a tapered shape corresponding to the seal surface 35. The rotating shaft 43 is common to two cylinders, and two valve bodies 36 are attached to one rotating shaft 43. Therefore, the flow path switching valve 5 as a whole is provided with two rotating shafts 43. The two rotating shafts 43 are driven by the actuator 5a via an interlocking mechanism such as an appropriate link mechanism, and simultaneously open and close symmetrically. That is, the four valve bodies 36 open and close all at once. As shown also in FIG. 3, in order to rotatably support the rotating shaft 43, bearing portions 45 are integrally formed at three locations in the valve housing 31 with respect to each rotating shaft 43.

  The arm 44 has a plate shape extending in the radial direction from the rotation shaft 43 and swings about the rotation shaft 43. A support hole 48 in which a support pin 47 rising from the upper surface side of the valve body 36 is loosely fitted is formed at the tip of the arm 44. A stopper washer 49 is fixed to the tip of the support pin 47, and the gap between the washer 49 and the valve body 36 is set larger than the thickness of the arm 44. Therefore, the valve body 36 can rotate around the axis of the support pin 47 with respect to the arm 44, and, as shown in FIG. .

  As shown in FIG. 5, the valve side wall portion 38 in the port upstream portion 33 of the valve port 32 avoids the valve port flow path 33 </ b> A when the valve body 36 is in the open posture in which it rises upstream. The valve accommodating portion 50 for accommodating the valve body 36, the arm 44, and the rotating shaft 43 in an open posture is recessed so as to be retracted to a position outside the flow path 33A of the port upstream portion 33. That is, the port side wall portion 38 partially protrudes in a direction away from the valve port 32, and the valve accommodating portion 50 is formed therein. Here, the “flow path 33 </ b> A” of the port upstream portion 33 of the valve port 32 is a port upstream of the valve accommodating portion 50 in a section of the valve accommodating portion 50, as indicated by a one-dot chain line in FIG. 5. It means a cylindrical space continuous from the side wall 38.

  Further, a reservoir 51 that can temporarily store condensed water is provided in a recessed manner at a position that is laterally removed from the flow path 33A of the port upstream portion 33 and below the valve accommodating portion 50 and the rotary shaft 43. Has been. The valve accommodating part 50 and the storage part 51 are integrally formed in the port side wall part 38 at the time of casting as one smoothly continuous recessed part. In other words, the upper portion of one recess formed by projecting the port side wall portion 38 outward functions as the valve housing portion 50, and the lower portion functions as the storage portion 51. The storage unit 51 extends so as to cover at least the entire vertical lower range of the rotation shaft 43, and the volume and the rotation shaft 43 are arranged so that the stored condensed water does not reach the rotation shaft 43. Dimensions such as depth are set appropriately. That is, the storage part 51 is disposed obliquely below the seal surface 35.

  Here, the entire rotation shaft 43, including the large diameter portion 43 </ b> A (FIG. 3) connected to the arm 44, does not hinder the exhaust flow of the port upstream portion 33. Although arranged on the outer side and the side, the valve body 36 is arranged as close as possible to the seal surface 35 so as to make the rotation locus of the valve body 36 as small as possible. Specifically, the rotation shaft 43 is disposed obliquely above and directly outside the seal surface 35, and a part of the rotation shaft 43 enters below the upper end of the seal surface 35 (see FIG. 5). .

  In order to prevent the valve body 36 from shaking in the open posture, the abutting portion 52 to which the tip of the support pin 47 and the washer 49 in the valve body 36 in the open posture are abutted is set on the side wall of the valve housing portion 50. Has been. Here, the valve body 36 in the open posture is set to have a posture in which the downstream side is inclined in a direction away from the flow path 33A. Specifically, the abutting portion 52 is appropriately inclined. . And as shown in FIG. 6, it is set so that the lower end of the valve body 36 of an open posture may oppose the surface of the arm 44 through the slight clearance L1. That is, the condensed water adhering to the surface of the valve body 36 in the open posture is surely flown down to the storage portion 51 through the arm 44 and is not scattered to the downstream side of the valve port 32. The gap L1 is set appropriately.

  Further, when the valve body 36 is in the open posture, the condensed water stored in the storage portion 51 is caused by exhaust gas flowing in the valve housing portion 50 as indicated by arrows Y1 to Y3 in FIG. The gap L2 between the valve housing 31, more specifically, the upper surface of the valve housing 50 and the valve body 36 in the open position is set to be sufficiently small so that the port 32 is not scattered or swept out to the flow path 33A side. In addition, the gap L3 between the valve housing 31 and, more specifically, the upper edge of the reservoir 51 on the valve port side, and the rotary shaft 43 is set to be sufficiently small. In particular, in order to make the gap L2 small, as shown in FIGS. 3 and 4, the valve housing 31 has an appropriate built-up portion 53 so as to fill the gap with the valve body 36 in the open posture. Is provided.

  (A)-(D) of FIG. 7 has shown the modification examples 51A-51D of the storage part 51 mentioned above, respectively. Here, the shape of the valve housing 31 is simply shown. The shape of the reservoir is not particularly limited as long as the volume and depth are such that the condensed water is not immersed in the rotating shaft 43. For example, in the storage section 51A of (A), the bottom surface has a hemispherical curved shape. The reservoir 51B of (B) has a flat bottom surface. In the storage part 51C of (C) and the storage part 51D of (D), the bottom face is V-shaped. In addition, in the storage part 51D of (D), the V-shaped lower end part of the storage part 51D is connected to the valve port 32 in order to more reliably prevent the condensed water stored in the storage part 51D from splashing toward the valve port side. It is offset to the far side.

  Further, as shown in FIG. 7, each of the storage parts 51 (51 </ b> A to 51 </ b> D) has a water holding material 54 (54 </ b> A to 54 </ b> D) that can absorb or temporarily hold / trap the condensed water accumulated in the storage part 51. Is arranged. Specifically, as the water holding material 54, a porous material that is formed of a material having excellent heat resistance such as alumina and that can hold and trap moisture is used. Each of the water retaining members 54A to 54D preferably has a shape corresponding to the shape of the storage portions 51A to 51D (near the bottom thereof), and is stored by an appropriate fixing means using adhesion, locking, or a fixture. The parts 51A to 51D are fixed and held. By using such water-holding materials 54A to 54D, the condensed water accumulated in the storage unit 51 can be temporarily held, and scattering of the condensed water can be more reliably prevented.

  FIGS. 8-10 shows the example of the valve body side storage part 55 (55A-55C) and the water holding | maintenance material 56 (56A-56C) which are each provided in the said valve body 36, (B) is A- of (A). It is sectional drawing which follows A line. As shown in each figure, a valve body-side storage portion 55 that stores condensed water is recessed in the upper surface 36A of the valve body 36 that faces the upstream side of the port when the valve is closed. Further, similarly to the water holding material 54 described above, a water holding material 56 capable of temporarily holding condensed water is arranged in each valve body side storage portion 55. Each of the water retaining members 56A to 56C is set to have substantially the same shape and dimensions as the corresponding valve body side reservoirs 55A to 55C, and is fitted and held in the valve body side reservoirs 55A to 55C by appropriate fixing means.

  As described above, since the valve body 36 is configured to be rotatable around the axis, the valve body side reservoirs 55A to 55C and the water holding members 56A to 56C fitted to the valve body side reservoirs 55A to 55C are temporarily disposed with respect to the center 57 of the valve body 36. If it is provided with an asymmetric shape, for example, eccentric in a certain direction, good rotation around the axis of the valve body 36 is hindered, and the effect of suppressing uneven wear due to rotation around this axis may be hindered. Therefore, in the valve body 36 of FIGS. 8 to 10, the valve body side storage portion 55 and the water retaining material 56 fitted thereto are set to have a symmetrical shape with the center 57 (center of gravity) of the valve body as the center.

  Specifically, in the example of FIG. 8, the valve body side storage portion 55 </ b> A is set in a cylindrical shape having a predetermined depth (thickness) centered on the valve body center 57. In the example of FIGS. 9 and 10, the valve body side storage portions 55 </ b> B and 55 </ b> C are set in a cross shape including two grooves 58 that intersect at the valve body center 57. Here, all the crossing angles α of both grooves 58 are set to the same angle, that is, 90 degrees, and the valve body side reservoirs 55B and 55C are set symmetrically with respect to the valve body center 57 as a whole. Furthermore, in the example of FIG. 10, tapered surface portions 59 whose bottom surfaces gradually become shallower toward the outer peripheral side are formed at both ends of each groove 58. By providing such a tapered surface portion 59, when opening the valve body 36, the condensed water can be favorably transmitted to the arm 44 side and guided to the storage portion 51 below the rotating shaft 43.

  11 and 12 show examples of the arm-side reservoir 60 (60A, 60B) and the arm-side water retaining member 61 (61A, 61B) provided in the arm 44, respectively, and (B) is an A of (A). It is sectional drawing which follows the -A line. An arm-side reservoir 60 is recessed in the upper surface 44A of the arm 44 that faces the upstream side of the port when the valve is closed, and the condensed water is temporarily stored in the arm-side reservoir 60 in the same manner as the water retaining material 54 described above. An arm-side water holding material 61 made of alumina or the like to be held is disposed. Further, when the valve body 36 is opened, the above-described arm-side storage is performed so that the condensed water held in the arm-side storage unit 60 is guided well without being scattered through the rotating shaft 43 to the storage unit 51 below. The portion 60 is extended to a connection portion with the rotation shaft 43, that is, a root portion to the rotation shaft 43. Furthermore, in the example of FIG. 12, the bottom surface is inclined so that the arm-side reservoir 60 </ b> B becomes deeper as the rotation shaft 43 is approached so that the condensed water is more reliably guided to the rotation shaft 43 side.

  Although not shown here, a slit, a groove or a hole connected to the arm-side reservoir 60 may be formed on the rotating shaft 43 side so as to guide the condensed water to the reservoir 51 more reliably. Good.

  FIGS. 13A to 13C show examples of cross-sectional shapes of the arm-side reservoir 60 and the arm-side water retaining member 61, respectively, and are cross-sectional corresponding views taken along line BB in FIG. As shown in the figure, the cross-sectional shapes of the arm-side reservoirs 60C to 60E and the water retaining members 61C to 61E are suitable according to performance and manufacturing requirements, such as rectangular, triangular (V-shaped) or hemispherical. Can be set to any shape.

  The characteristic configuration of the present embodiment as described above and the operation and effects thereof are listed below.

  (1) It has the flow-path switching valve 5 which opens and closes the valve port 32 through which exhaust flows from the vertically upper side to the vertically lower side. The flow path switching valve 5 includes a valve housing 31 in which a valve port 32 is formed, a rotating shaft 43 rotatably supported by the valve housing 31, an arm 44 extending in a radial direction from the rotating shaft 43, And a valve body 36 attached to the tip of the arm 44 and seated on a seal surface 35 surrounding the valve port 32 when closed. The valve housing 31 accommodates the valve body 36, the arm 44, and the rotating shaft 43 in the open position so that the valve body 36 is retracted from the flow path 33 </ b> A of the valve port 32 when the valve body 36 is in the open position in which the valve body 36 stands upstream. The valve housing portion 50 is recessed in the port side wall portion 38 of the valve port 32 and is located at a position deviated from the flow path 33A of the valve port 32 and below the valve housing portion 50. 51 is recessed.

  With such a configuration, when the valve is closed, the condensed water generated upstream of the valve body 36 can be received by the storage portion 51, and when the valve body 36 is opened, it adheres to the surfaces of the valve body 36 and the arm 44. Even if the condensed water flows out, it can be received by the storage portion 51 that is recessed below the valve accommodating portion 50 that accommodates the valve body 36, the arm 44, and the rotating shaft 43 in the open posture. It is possible to prevent the condensed water from flowing out to the path 33A. The water stored in the storage part 51 will quickly evaporate as the temperature rises due to the heat of the exhaust gas flowing through the valve port 32 after the valve is opened.

  (2) Since the valve housing portion 50 and the storage portion 51 are recessed in the port side wall portion 38 of the valve housing 31 as a single concave portion that smoothly continues, as shown in FIG. The shape is also relatively simple and compact, and the valve housing part 50 and the storage part 51 can be easily formed by casting, for example.

  (3) Preferably, as shown in FIGS. 8 to 10, the reservoir 55 is also recessed in the upper surface 36 </ b> A of the valve body 36 that faces the upstream side of the valve port 32 when the valve body 36 is closed. Thereby, the condensed water adhering to the upper surface of the valve body 36 can be positively received in the storage portion 55. The condensed water stored in the storage unit 55 is guided to the storage unit 51 below the valve storage unit 50 through the arm 44 and the rotating shaft 43 when the valve body 36 is opened.

  (4) The valve body 36 is rotatably supported at the tip of the arm 44. This is because the contact position between the valve body 36 and the seal surface 35 is changed in the circumferential direction so that the valve body 36 is uniformly worn in the circumferential direction to prevent uneven wear. For this reason, if the reservoir 51 has an asymmetric shape with respect to the valve body center 57, the above-described good rotation of the valve body 36 is hindered, which may cause uneven wear. Therefore, as shown in FIGS. 8 to 10, the storage portion 55 of the valve body 36 is symmetrical with respect to the valve body center 57.

  (5) More preferably, as shown in FIGS. 11 and 12, the arm-side reservoir 60 is also recessed in the upper surface 44A of the arm 44 facing the upstream side of the valve port 32 when the valve body 36 is closed. Yes. As a result, the condensed water adhering to the upper surface of the arm 44 can be positively received in the arm-side reservoir 60. The condensed water stored in the arm-side storage unit 60 is received by the storage unit 51 below the valve housing unit 50 through the rotating shaft 43 when the valve body 36 is opened.

  (6) Preferably, the reservoir 60 of the arm 44 is connected to the rotary shaft 43, that is, the rotary shaft 43 side so that the condensed water is reliably guided to the reservoir 51 through the rotary shaft 43. It extends to the base part of.

  (7) By providing the water retaining materials 54, 56, 61 capable of temporarily holding condensed water in the storage parts 51, 55, 60, the storage parts are caused by the exhaust gas flow or the like when the valve is opened. It is possible to suppress / avoid the condensate accumulated in the water from being scattered or taken out. Condensed water retained by the water retaining material will gradually evaporate as the temperature rises due to exhaust heat and the like, and condensate remains in the reservoirs 55 and 60 when the valve body 36 is opened. However, it is received by the storage part 51 below the valve accommodating part 50 through the arm 44 and the rotating shaft 43 and does not flow out to the exhaust passage on the downstream side of the valve body.

  (8) For the water retaining materials 54, 56, 61 described above, for example, a porous material used in a filter or the like can be applied. This porous material is formed of alumina or the like having excellent heat resistance, and has a porous shape that can temporarily hold and trap moisture.

  (9) In the case where a sensor component such as the air-fuel ratio sensor 10 is disposed in the exhaust passage downstream of the valve body 36, if moisture flows out to the downstream side of the valve body and scatters on the sensor component, the sensor component may fail. Since there is a risk of incurring, the above-described embodiment is extremely useful.

  (10) Typically, the bypass passage 7 is provided in parallel with the upstream portion of the main passage 3 provided with the main catalytic converter 4 on the downstream side, and the bypass catalytic converter 8 is provided in the bypass passage 7. The flow path switching valve 5 is provided in the upstream portion of the main passage 3 and closes the main passage 3. Immediately after the cold start, the flow path switching valve 5 is closed, the exhaust gas is guided to the bypass passage 7 side, and exhaust purification is performed.

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes without departing from the spirit of the present invention. . For example, in the above embodiment, the description has been given by taking the four-cylinder internal combustion engine as an example. However, the present invention is not limited to this, and the present invention can be applied to other multi-cylinder internal combustion engines such as a V-type cylinder and six cylinders. In the above embodiment, the valve port 32 extends substantially linearly along the vertical direction. However, the present invention is not limited to this, and the valve port 32 may be curved or inclined according to specifications and requirements.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration explanatory diagram of an intake and exhaust system of an internal combustion engine to which an exhaust device according to an embodiment of the present invention is applied. The perspective view which shows the flow-path switching valve of a present Example. The partially broken perspective view which shows the said flow-path switching valve. Sectional drawing which shows the said flow-path switching valve. The principal part sectional view in the valve opening attitude | position of the said flow-path switching valve. The principal part enlarged view of FIG. Sectional drawing which shows simply the example of a shape (A)-(D) of the storage part below a valve accommodating part, and a water holding member. The top view (A) and sectional drawing (B) which show an example of the storage part provided in a valve body, and a water holding material. The top view (A) and sectional drawing (B) which show the other example of the storage part provided in a valve body, and a water holding material. The top view (A) and sectional drawing (B) which show the other example of the storage part provided in a valve body, and a water holding material. The top view (A) and sectional drawing (B) which show an example of the storage part provided in an arm, and a water holding material. The top view (A) and sectional drawing (B) which show the other example of the storage part provided in an arm, and a water holding material. Sectional drawing which follows the BB line of FIG. 12 which shows the cross-sectional shape example (A)-(C) of the storage part provided in an arm, and a water holding material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Main passage 4 ... Main catalytic converter 5 ... Flow path switching valve 7 ... Bypass passage 8 ... Bypass catalytic converter 31 ... Valve housing 32 ... Valve port 33A ... Flow path 35 ... Sealing surface 36 ... Valve body 38 ... Port side wall 43 ... Rotary shaft 44 ... Arm 50 ... Valve storage part 51,55,60 ... Storage part 54,56,61 ... Water holding member

Claims (10)

It has a flow path switching valve that opens and closes a valve port through which exhaust flows from the vertically upper side to the vertically lower side,
This flow path switching valve
A valve housing in which the valve port is formed;
A rotating shaft rotatably supported by the valve housing;
An arm extending in a radial direction from the rotation axis;
A valve body attached to the tip of the arm and seated on a sealing surface surrounding the valve port when closed,
In the valve housing, when the valve body is in an open posture in which the valve body stands upstream, a valve housing portion that houses the valve body, the arm, and the rotating shaft in the open posture is recessed in the port side wall portion of the valve port. With
An exhaust system for an internal combustion engine, characterized in that a condensate reservoir is recessed at a position deviating from the flow path of the valve port and below the valve housing.   2. The exhaust system for an internal combustion engine according to claim 1, wherein the valve housing part and the storage part are formed in the valve housing as one concave part that smoothly continues.   The exhaust device for an internal combustion engine according to claim 1 or 2, wherein a condensate reservoir is recessed on an upper surface of the valve body facing the upstream side of the valve port when the valve body is closed. . The valve body is rotatably supported at the tip of the arm,
The exhaust device for an internal combustion engine according to claim 3, wherein the storage part of the valve body has a symmetrical shape with respect to the center of the valve body.   The internal combustion engine according to any one of claims 1 to 4, wherein a condensate reservoir is recessed in the upper surface of the arm facing the upstream side of the valve port when the valve body is closed. Exhaust system.   6. The exhaust system for an internal combustion engine according to claim 5, wherein the storage part of the arm extends to a connection part with the rotating shaft.   The exhaust device for an internal combustion engine according to any one of claims 1 to 6, wherein a water holding material is provided in the storage part.   The exhaust device for an internal combustion engine according to claim 7, wherein the water retaining material is a porous material having a porous shape.   The exhaust device for an internal combustion engine according to any one of claims 1 to 8, wherein a sensor component is disposed in an exhaust passage downstream of the valve port. A bypass passage is provided in parallel with the upstream portion of the main passage provided with the main catalytic converter on the downstream side, and the bypass catalytic converter is provided in the bypass passage,
The exhaust device for an internal combustion engine according to any one of claims 1 to 9, wherein the flow path switching valve is provided in an upstream portion of the main passage and closes the main passage.

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