JP6354693B2 - Exhaust system for multi-cylinder engine - Google Patents

Description

  The present invention relates to an exhaust device for a multi-cylinder engine.

  2. Description of the Related Art Conventionally, in an engine such as an automobile, an exhaust system for an engine that increases engine torque by promoting exhaust using the ejector effect has been developed.

  In an exhaust device that promotes exhaust using the ejector effect, for example, as described in Patent Document 1, the engine area can be increased more effectively by changing the flow passage area of the exhaust passage. There is what I did.

  The exhaust system of the engine described in Patent Document 1 is such that the flow area decreases toward the downstream side in order from the upstream side to the downstream side portion of the independent exhaust passage connected to each of the plurality of cylinders. And a constricted portion formed with a plurality of gas passages that communicate with each other independently, a tubular confluence portion where the exhaust gas that has passed through each gas passage merges, and a tubular shape in which the flow area increases toward the downstream side A diffuser unit is provided, and the flow channel area of each gas passage in the throttle unit can be changed.

  The throttle portion, the merging portion, and the diffuser portion constitute a so-called dynamic pressure exhaust system. That is, the dynamic pressure exhaust system raises the flow rate of the exhaust gas flowing in from the independent exhaust passage at the throttle part and causes the high-speed exhaust gas to flow into the merge part to generate a negative pressure in the merge part. The exhaust gas is sucked out (scavenged) from other independent exhaust passages.

  The structure of the aperture portion will be specifically described. The throttle part is composed of an inner pipe connected to the independent exhaust passage, and an outer pipe surrounding the peripheral surface of the inner pipe, the merging part, and a cylindrical movable part formed by integrating the diffuser part. ing. The diameter of the inner tube is reduced toward the downstream side, and an opening for communicating the inside of the inner tube with the outside of the inner tube is formed in the peripheral wall. The outer tube has a smaller diameter toward the downstream side. Between the inner pipe and the outer pipe, there is formed a flow path that guides the exhaust gas flowing out from the opening formed in the peripheral wall of the inner pipe to the junction. By displacing the outer pipe (movable part) along the flow direction of the exhaust gas with respect to the inner pipe, the flow area between the inner pipe and the outer pipe, and consequently the flow area of the gas passage in the throttle part is changed. Is done.

  As a method of displacing the movable part along the flow direction of the exhaust gas, for example, it is conceivable to displace the movable part by a link mechanism and an actuator. Specifically, for example, it is conceivable to connect, via a link mechanism, a pin protruding from the outer peripheral surface of the movable part and an actuator that performs a linear operation at a position away from the central axis of the movable part. When the actuator is operated, the link mechanism swings along the exhaust gas flow direction, and the movable part is displaced along the exhaust gas flow direction along with the swing.

JP2013-57255A

  However, since the movable portion receives a force in the direction from the exhaust gas toward the downstream side, in order to maintain the state in which the movable portion is displaced upstream, a large driving force that opposes the force that the movable portion receives from the exhaust gas is applied. As a result, there is a possibility that the actuator becomes large.

  The present invention has been made in view of the above circumstances, and the movable part is displaced upstream by the actuator while downsizing the actuator that displaces the movable part of the dynamic pressure exhaust system in the upstream and downstream directions. An object of the present invention is to provide an exhaust device for a multi-cylinder engine that can stably maintain a state.

  In order to solve the above-described problems, the present invention provides a plurality of independent exhaust passages that are independently connected to a plurality of cylinders of an engine having a plurality of cylinders, or a branching in the middle portion and the exhaust order is continuous. Nozzle portion formed with a plurality of internal passages extending from a plurality of independent exhaust passages including independent exhaust passages connected to a plurality of cylinders to which gas discharged from each of the independent exhaust passages flows independently And an inflow part into which the gas discharged from the nozzle internal passage flows in, and an aggregation part in which the gas that has passed through the inflow part gathers, and the gas flow is downstream of the nozzle part in the gas flow direction. Cylindrical movable which is provided so as to be displaceable in the upstream and downstream directions and reduces the flow area of the inflow portion when displaced upstream, and expands the flow area of the inflow portion when displaced downstream And the movable part A moving mechanism for displacing in the upstream / downstream direction, the moving mechanism having a rocking center at a position radially outside of the movable portion and provided so as to be rockable along the upstream / downstream direction. An operating portion provided in the movable portion, and an operated portion that displaces the movable portion in the upstream / downstream direction as the operating portion swings, and a position radially outside the movable portion. An eccentric cam, an actuator that applies a rotational force to the eccentric cam, a displacement portion that is displaced in the upstream / downstream direction with the rotation of the eccentric cam, a pivot portion that is disposed at the swing center, and the pivot A multi-cylinder engine exhaust system comprising: a pivot support portion that supports a portion; and a connecting portion that connects the displacement portion, the pivot portion, and the operation portion.

  According to the present invention, it is possible to reduce the driving force required for the actuator in order to maintain the state in which the movable part is displaced upstream, and thus it is possible to reduce the size of the actuator. More specifically, in order to maintain the state where the movable part is displaced upstream (the state where the flow path area of the inflow part is reduced), the movable part is not displaced downstream by the pressure of the exhaust gas. It is necessary to cause the actuator to generate a driving force in a direction that displaces the movable part upstream. In this configuration, the force that the movable part receives from the exhaust gas is transmitted to the actuator via the eccentric cam and the displacement part. Therefore, the force for rotating the eccentric cam by the exhaust gas (hereinafter referred to as “cam rotation by the exhaust gas”). Force ") is reduced between the eccentric cam and the displacement part, thereby reducing the driving force required for the actuator to counter the cam rotational force due to the exhaust gas.

  Further, according to this configuration, the force that the exhaust gas presses the movable portion downstream is transmitted to both the pivot support portion and the eccentric cam, so that the pressing force is distributed to the pivot support portion and the eccentric cam. The Thereby, the cam rotational force by exhaust gas is reduced, and as a result, the driving force required for the actuator can be reduced.

  In the present invention, the actuator applies a rotational force to the camshaft fixed to the eccentric cam, and when the movable portion is at the most upstream position in the movable region, the axis of the camshaft is the eccentricity. It is preferable that the cam is positioned in the vicinity of a reference line passing through the radial center of the cam and along the upstream and downstream directions.

  According to this configuration, the cam rotational force generated by the exhaust gas has a magnitude near zero, so that the driving force required for the actuator can be significantly reduced.

  In the present invention, the actuator applies a rotational force to a camshaft fixed to the eccentric cam, and the pivot support portion connects the pivot portion in a direction connecting the pivot portion and the camshaft. It is preferable that the support is slidable.

  According to this configuration, when the eccentric cam rotates, when the displacement portion is displaced in a predetermined direction connecting the pivot portion and the camshaft while being displaced in the upstream / downstream direction, the pivot portion is accompanied by the displacement of the eccentric cam. Since it is displaced in a predetermined direction, the movable part can be smoothly displaced in the upstream and downstream directions.

  In the present invention, the operation section includes a first surface made of a concave surface having an arcuate cross section on one side in the upstream / downstream direction, and a second surface made of a convex surface having an arcuate cross section on the other side in the upstream / downstream direction. The operated portion is provided on an outer peripheral portion of the movable portion, and has a convex surface along the first surface of the operating portion and a concave surface along the second surface of the operating portion. And a groove portion having an inner wall surface that supports the operation portion from both sides in the upstream and downstream directions so that the operation portion can be slid by a concave surface, and the movable portion slides within the groove portion as the operation portion swings. Is preferably displaced in the upstream / downstream direction.

  According to this structure, the 1st surface and 2nd surface of an operation part are supported by the inner wall surface of the groove part which an to-be-operated part has so that a slide is possible from both sides of an up-down direction. Since the operation part has a contact surface with the operated part formed in an arc shape in cross section, the contact area with the operated part becomes larger than in the case where the contact surface is not in an arc shape in cross section. Accordingly, since the first surface of the operation unit contacts the convex surface of the operated portion with a wide contact area, and the second surface of the operation unit contacts the concave surface of the operated portion with a wide contact area, the operation unit is operated. The occurrence of galling, sticking, and excessive wear due to contact with the part is suppressed, rattling is less likely to occur, and the generation of contact noise is also suppressed.

In the present invention, the actuator includes a rod and an actuator body that applies a rotational force to a camshaft fixed to the eccentric cam by reciprocating the rod, and the moving mechanism includes the rod It is preferable that a lever connected to the lever is further provided, and the camshaft is fixed to a position of the lever that is separated from a connecting portion between the lever and the rod.

  According to this configuration, it is possible to reduce the driving force (tensile force or pressing force) required for the actuator (direct acting actuator) in order to keep the movable portion displaced upstream. More specifically, the cam rotational force due to the exhaust gas is transmitted to the rod through the lever. In order to counter this cam rotational force, the actuator body needs to apply a force in the direction of pulling or pressing the lever to the rod. According to this configuration, as described above, since the cam rotational force due to the exhaust gas is reduced, the driving force (tensile force or pressing force) required for the actuator can be reduced.

  As described above, according to the present invention, it is possible to reduce the size of the actuator that displaces the movable part of the dynamic pressure exhaust system in the upstream and downstream directions, and to stabilize the state in which the movable part is displaced upstream by the actuator. Can be held.

1 is a schematic configuration diagram of an exhaust device for a multi-cylinder engine according to a first embodiment of the present invention. 1 is a schematic side view of an exhaust device for a multi-cylinder engine according to a first embodiment of the present invention. 1 is a schematic front view of an exhaust device for a multi-cylinder engine according to a first embodiment of the present invention. It is a figure which shows the downstream end part of a nozzle part. It is a V direction arrow directional view in FIG. It is a fragmentary sectional view which shows the exhaust apparatus of a multicylinder engine when a movable part exists in a most upstream position. It is a fragmentary sectional view which shows the exhaust apparatus of the multicylinder engine shown in FIG. 6 in the state which cut | disconnected the moving mechanism along the upstream / downstream direction of a gas flow. It is a fragmentary sectional view which shows the exhaust apparatus of a multicylinder engine when a movable part exists in the most downstream position. It is a fragmentary sectional view which shows the exhaust apparatus of the multicylinder engine shown in FIG. 8 in the state which cut | disconnected the moving mechanism along the upstream / downstream direction of a gas flow. It is sectional drawing which shows a motion of the moving mechanism which concerns on 1st Embodiment, (a) is a figure which shows a state when a movable part exists in a most upstream position, (b) is a state when a movable part exists in a midstream position (C) is a figure which shows a state when a movable part exists in a most downstream position. It is a figure which shows the force which acts on the eccentric cam of the moving mechanism which concerns on 1st Embodiment, (a) is a figure which shows a state when a movable part exists in a most upstream position, (b) is a figure which shows a movable part in a midstream position. The figure which shows a state at a time, (c) is a figure which shows a state when a movable part exists in a most downstream position. It is a figure which shows the force which acts on the eccentric cam of the moving mechanism which concerns on 1st Embodiment, a pivot part, an operation part, and an actuator, and is a figure which shows a state when a movable part exists in a most upstream position. It is a figure which shows the force which acts on an operation part and an actuator when it fixes to a lever part and a rocking | fluctuation arm, and is a figure which shows a state when a movable part exists in a most upstream position. It is the figure which showed the driving | running state (operation area | region) of the engine in 1st Embodiment of this invention. In the exhaust system for a multi-cylinder engine according to the second embodiment of the present invention, it is a partial cross-sectional view showing a state when the movable portion is at the most upstream position. In the exhaust system for a multi-cylinder engine according to the second embodiment of the present invention, FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an exhaust device 100 for a multi-cylinder engine according to an embodiment of the present invention. FIG. 2 is a schematic side view of FIG. FIG. 3 is a schematic front view of FIG. In FIG. 1, illustration of a moving mechanism 90A described later is omitted.

  In the following description, the upstream side in the exhaust gas flow direction is “upstream side”, the downstream side in the exhaust gas flow direction is “downstream side”, the upstream end is “upstream end”, and the downstream side is The end portion is referred to as a “downstream end portion”, and the direction along the flow of the exhaust gas is referred to as an “upstream / downstream direction”.

  As shown in FIG. 1, an exhaust device 100 for a multi-cylinder engine in the present embodiment is attached to the engine 1. The engine 1 according to the present invention is an in-line four-cylinder four-cycle gasoline engine in which four cylinders 12a to 12d are arranged in the vehicle width direction. The cylinder head 9 of the engine 1 is formed with a first cylinder 12a, a second cylinder 12b, a third cylinder 12c, and a fourth cylinder 12d in order from the right side of the vehicle along the vehicle width direction.

  In the engine 1, the air-fuel mixture in the cylinder is ignited at a timing shifted by 180 ° C. in each of the cylinders 12 a to 12 d so that the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke are shifted by 180 ° A. It is configured. In the present embodiment, ignition is performed in the order of the first cylinder 12a → the third cylinder 12c → the fourth cylinder 12d → the second cylinder 12b, and the exhaust stroke and the like are performed in this order.

  As shown in FIG. 1, the cylinder head 9 of the engine 1 is provided with a spark plug 15 for igniting the air-fuel mixture at a position facing the combustion chamber of each cylinder 12.

  In the cylinder head 9, two intake ports 17 and two exhaust ports 18 are formed for each cylinder 12. The intake port 17 is for introducing intake air into each cylinder 12. The exhaust port 18 is for exhausting the exhaust from each cylinder 12. Each intake port 17 is provided with an intake valve 19 for opening and closing the intake port 17 to communicate or block the intake port 17 and the inside of the cylinder 12. Each exhaust port 18 is provided with an exhaust valve 20 for opening and closing the exhaust port 18 to communicate or block the exhaust port 18 and the inside of the cylinder 12. The intake valve 19 is driven by an intake valve drive mechanism 30 to open and close the intake port 17, and the exhaust valve 20 is driven by an exhaust valve drive mechanism 40 to open and close the exhaust port 18.

  The intake valve drive mechanism 30 includes an intake camshaft 31 connected to the intake valve 19 and an intake VVT (Valiable Valve Timing) 32. The intake camshaft 31 is connected to the crankshaft via a known power transmission mechanism such as a chain / sprocket mechanism, and rotates with the rotation of the crankshaft to open and close the intake valve 19. The intake VVT 32 changes the phase difference between the intake camshaft 31 and a predetermined driven shaft that is arranged coaxially with the intake camshaft 31 and is directly driven by the crankshaft. As a result, the intake VVT 32 changes the phase difference between the crankshaft and the intake camshaft 31, that is, the valve timing of the intake valve 19. As the intake VVT 32, a hydraulic type or an electromagnetic type is used.

  The exhaust valve drive mechanism 40 has substantially the same structure as the intake valve drive mechanism 30, and the exhaust camshaft 41 connected to the exhaust valve 20 and the crankshaft, and the phase difference between the exhaust camshaft 41 and the crankshaft. And an exhaust VVT 42 that changes the valve timing of the exhaust valve 20 by changing the above.

  Next, the configuration of the exhaust device 100 for a multi-cylinder engine according to the present embodiment will be described in detail.

  As shown in FIG. 1, an exhaust device 100 for a multi-cylinder engine includes four independent exhaust pipes 52 that are independently connected to the cylinders 12a to 12d of the engine 1 and bundled at their downstream ends, and independent exhaust pipes. 52, a dynamic pressure exhaust system 60A connected to the downstream end of 52, a downstream exhaust pipe 80 connected to the downstream end of the dynamic pressure exhaust system 60A, and a movable portion 62 (described later) of the dynamic pressure exhaust system 60A in the upstream and downstream directions. A moving mechanism 90A (see FIGS. 2 and 3) for displacement.

<Configuration of downstream side exhaust pipe 80>
The downstream exhaust pipe 80 is a substantially cylindrical member in which one passage is formed. As will be described later, the exhaust gas discharged from each cylinder 12 passes through each independent exhaust pipe 52 independently, then merges in the dynamic pressure exhaust system 60A, and then passes through the downstream exhaust pipe 80. It is discharged outside the exhaust device 100. A catalyst device, a muffler, and the like are arranged in the downstream side exhaust pipe 80.

<Configuration of independent exhaust pipe 52>
The independent exhaust pipe 52 is a member extending downstream from the exhaust port 18 of the cylinder 12 as shown in FIG. Each independent exhaust pipe 52 is formed with an independent exhaust passage 52a that guides the exhaust gas discharged from the cylinder 12 to the dynamic pressure exhaust system 60A. Each independent exhaust pipe 52 extends toward the upstream end of the dynamic pressure exhaust system 60A, is bundled near the upstream end of the dynamic pressure exhaust system 60A, and is connected to the upstream end of the dynamic pressure exhaust system 60A.

<Configuration of dynamic pressure exhaust system 60A>
The dynamic pressure exhaust system 60A increases the flow rate of the exhaust gas discharged from the independent exhaust pipe 52, generates a negative pressure with the high-speed exhaust gas, and sucks the exhaust gas from the other independent exhaust pipe 52 with the negative pressure. It is configured to (scavenge). As shown in FIG. 1, the dynamic pressure exhaust system 60 </ b> A as a whole has its flow path area gradually reduced toward the downstream side and then extended while maintaining a constant state, and then toward the downstream side. It has a shape that gradually increases.

  As shown in FIG. 1, the dynamic pressure exhaust system 60A includes a cylindrical outer shell 61 having an upstream end connected to the independent exhaust pipe 52 and a downstream end connected to the downstream exhaust pipe 80, and the outer shell 61 Each having a nozzle part 64, a movable part 62, and a diffuser part 63 accommodated therein. The nozzle part 64, the movable part 62, and the diffuser part 63 are arranged in this order from the upstream side.

<Configuration of nozzle part 64>
As shown in FIG. 7, the nozzle portion 64 is a tubular member extending in the upstream / downstream direction, and extends from the downstream end of the independent exhaust pipe 52 to the downstream side. The nozzle portion 64 is disposed at the upstream end portion in the outer shell 61. The nozzle portion 64 is formed with four in-nozzle passages 64a (see FIGS. 4 and 7) into which the exhaust discharged from the independent exhaust passages 52 flows independently. The four in-nozzle passages 64a are provided corresponding to the four independent exhaust passages 52, respectively. As shown in FIGS. 4 and 7, the nozzle passages 64 a have the same structure and are arranged at equal intervals (90 ° intervals) around the central axis X <b> 1 of the nozzle portion 64.

  As shown in FIG. 7, the nozzle part 64 has a nozzle side straight part 64b and a nozzle side reduced diameter part 64c.

  The nozzle-side straight portion 64b has a cylindrical shape that extends downstream from the downstream end of the independent exhaust pipe 52 while maintaining the same diameter. The in-nozzle passage 64a in the nozzle-side straight portion 64b extends linearly along the central axis X1 of the nozzle portion 64.

  As shown in FIGS. 7 and 9, an upstream buffer member 65 is provided at the lower end of the peripheral wall of the nozzle side straight portion 64 b. The upstream buffer member 65 is a ring-shaped member attached to the outer peripheral surface of the nozzle portion 64. The outer peripheral surface of the upstream buffer member 65 has a shape (a cross-sectional arc shape) along an inner peripheral surface of a curved portion 62 a described later in the movable portion 62. Specifically, the outer peripheral surface of the upstream buffer member 65 is formed so as to form a part of a first spherical surface C1 having a radius R1 centered on a point P1 on the central axis X1 of the nozzle portion 64. That is, when the upstream buffer member 65 is cut along a plane passing through the central axis X1, the outer edge of the cut surface (the edge opposite to the central axis X1) becomes an arc shape. The point P1 is located upstream of the upstream buffer member 65 on the central axis X1.

  Although the material of the upstream buffer member 65 is not particularly limited, for example, it can be configured by combining expanded graphite and a stainless mesh. Specifically, for example, a belt-shaped stainless steel mesh sheet overlapped with a belt-shaped expanded graphite sheet is wound into a ring shape, and the wound material is pressure-molded so that the outer peripheral surface has a circular arc shape in cross section. Thus, the upstream buffer member 65 can be manufactured. A ring-shaped member using expanded graphite is generally used as a seal ring such as a gasket. In the present embodiment, the cost for the upstream buffer member 65 can be reduced by using the seal ring that is generally used as described above for the upstream buffer member 65.

  As shown in FIG. 7, the upstream buffer member 65 includes a nozzle portion 64 and a movable portion 62 when the movable portion 62 is displaced in the upstream direction to a predetermined position (the most upstream position in the movable region of the movable portion 62 described later). It is arrange | positioned so that it may be pinched | interposed between. That is, the upstream buffer member 65 is disposed so as to contact the curved portion 62a of the movable portion 62 when the movable portion 62 is displaced to the predetermined position. By being arranged in this way, the upstream buffer member 65 prevents the movable portion 62 from being displaced in the upstream direction from the predetermined position. That is, the upstream buffer member 65 defines the most upstream position (upstream position) of the movable region of the movable portion 62.

  The nozzle-side reduced diameter portion 64c extends from the downstream end of the nozzle-side straight portion 64b to the downstream side, and has a substantially truncated cone shape that is reduced in diameter toward the downstream side. That is, the peripheral wall of the nozzle-side reduced diameter portion 64c is configured to incline toward the central axis X1 as it goes downstream. Accordingly, the flow passage area of the nozzle inner passage 64a in the nozzle side reduced diameter portion 64c is smaller than the flow passage area of the nozzle inner passage 64a in the nozzle side straight portion 64b. Specifically, the flow path area in the nozzle-side straight part 64b is constant over the entire upstream and downstream direction, and the flow path area in the nozzle-side reduced diameter part 64c decreases toward the downstream side. The inner diameter of the downstream end of the nozzle part 64 is set to, for example, about half of the inner diameter of the upstream end of the nozzle part 64.

  As shown in FIGS. 4 and 7, the peripheral wall of the nozzle-side reduced diameter portion 64c is formed with an opening 64d that allows the inside and outside of the nozzle passage 64a to communicate with each other. As shown in FIG. 4, the openings 64 d are provided at equal intervals (at intervals of 90 °) around the central axis X <b> 1 of the nozzle portion 64. As shown in FIG. 5, a part of the peripheral wall of the nozzle-side reduced diameter portion 64c is cut out in a substantially semicircular shape from the downstream end toward the upstream side to form an opening 64d. Here, since the peripheral wall of the nozzle-side reduced diameter portion 64c is inclined toward the central axis X1 toward the downstream side as described above, the opening portion 64d opens toward the downstream side.

<Configuration of movable portion 62>
The movable portion 62 is a tubular member that is coaxial with the nozzle portion 64 and the outer shell 61 and extends in the upstream and downstream directions. The central axis X2 of the movable portion 62 is the central axis of the nozzle portion 64 when the movable portion 62 is at the most upstream position of the movable region (see FIG. 7) and when it is at the most downstream position (see FIG. 9). X1 and the center axis X3 of the outer shell 61 coincide.

  One path is formed in the movable portion 62. The movable portion 62 is driven by the actuator 70 and is displaced in the upstream and downstream directions in order to change the flow path area of the passage through which the exhaust gas flowing into the nozzle passage 64a from the independent exhaust passage 52a passes.

  As shown in FIGS. 7 and 9, the downstream end portion of the movable portion 62 is displaced in the upstream and downstream directions within the diffuser portion 63.

  The movable part 62 includes a curved part 62a, a movable side reduced diameter part 62b, and a movable side straight part 62c. The curved portion 62a and the movable side reduced diameter portion 62b correspond to the “inflow portion” of the present invention. The movable straight portion 62c corresponds to the “aggregation portion” of the present invention.

  As shown in FIGS. 7 and 9, the bending portion 62 a is a cylindrical portion extending from the upstream end of the movable portion 62 to the downstream side. The inner peripheral surface of the curved portion 62a is formed so as to form a part of the first spherical surface C1 having a radius R1 with the point P1 on the central axis X2 of the movable portion 62 as the center. That is, when the curved portion 62a is cut along a plane passing through the central axis X2, the inner edge of the cut surface (the edge on the central axis X2 side) becomes an arc shape. The point P1 is located on the upstream side of the curved portion 62a on the central axis X2.

  The movable-side reduced diameter portion 62b is a cylindrical portion that extends from the downstream end of the curved portion 62a to the downstream side, and has a shape that extends along the nozzle-side reduced diameter portion 64c. That is, the movable-side reduced diameter portion 62b is configured to incline toward the central axis X2 side of the movable portion 62 toward the downstream side, and is formed in a truncated cone shape whose diameter decreases toward the downstream side. Along with this, the flow path area of the movable-side reduced diameter portion 62b becomes smaller toward the downstream side.

  The curved portion 62 a and the movable-side reduced diameter portion 62 b are disposed so as to cover the downstream end portion of the nozzle portion 64.

  Specifically, as shown in FIGS. 6 and 7, when the movable portion 62 is displaced to the most upstream position, the curved portion 62a and the movable-side reduced diameter portion 62b of the movable portion 62 are replaced with the nozzle-side straight portion 64b. The downstream end portion of the nozzle, the nozzle-side reduced diameter portion 64c, and the upstream-side buffer member 65. The inner peripheral surface of the curved portion 62 a is in contact with the outer peripheral surface of the upstream buffer member 65. In this state, the curved portion 62a, the movable-side reduced diameter portion 62b, and the nozzle-side reduced diameter portion 64c are not in contact with each other, but their distances are small and close to each other.

  On the other hand, as shown in FIGS. 8 and 9, when the movable portion 62 is displaced to the most downstream position, the curved portion 62a and the movable-side reduced diameter portion 62b cover the nozzle-side reduced diameter portion 64c. In this state, the inner peripheral surface of the curved portion 62a is largely separated from the outer peripheral surface of the upstream buffer member 65.

  The raised portion 62d is provided at the downstream end of the movable-side reduced diameter portion 62b. As shown in FIGS. 6 to 9, the raised portion 62 d protrudes radially outward from the outer peripheral surface of the movable-side reduced diameter portion 62 b and is formed over the entire circumference of the movable-side reduced diameter portion 62 b. . The downstream portion of the raised portion 62d is cut out in a ring shape over the entire circumferential direction. A ring-shaped downstream buffer member 66 is attached to the notch.

  The outer peripheral surface of the downstream buffer member 66 has a shape (circular arc) along the inner peripheral surface (concave surface) of a bulging portion 61e of the outer shell 61 described later. Specifically, as shown in FIG. 9, the outer peripheral surface of the downstream buffer member 66 is a part of the second spherical surface C2 having a radius R2 centered on the point P2 on the central axis X2 of the movable portion 62. It is formed to make. That is, when the downstream buffer member 66 is cut along a plane passing through the central axis X2, the outer edge (edge opposite to the central axis X2) of the cut surface becomes an arc shape. The point P2 is located upstream of the downstream buffer member 66 on the central axis X2.

  The downstream buffer member 66 can be made of the same material as the upstream buffer member 65.

  As shown in FIGS. 8 and 9, the downstream buffer member 66 is movable with the outer shell 61 when the movable portion 62 is displaced in the downstream direction to a predetermined position (the most downstream position of the movable region of the movable portion 62 described later). It arrange | positions so that it may be pinched | interposed between the parts 62. That is, the downstream buffer member 66 is disposed so as to contact the inner peripheral surface of the bulging portion 61e of the outer shell 61 when displaced to the predetermined position. By being arranged in this manner, the downstream buffer member 66 prevents the movable portion 62 from being displaced in the downstream direction from the predetermined position. That is, the downstream buffer member 66 defines the most downstream position (most downstream position) of the movable region of the movable portion 62.

  As shown in FIGS. 6 and 7, when the movable portion 62 is displaced to the most upstream position, the movable-side reduced diameter portion 62b comes close to almost the entire nozzle-side reduced diameter portion 64c. As shown by the arrows, each opening 64d of the nozzle side reduced diameter portion 64c is substantially closed by the movable side reduced diameter portion 62b. Specifically, although there is a slight gap between the movable side reduced diameter part 62b and the nozzle part side reduced diameter part 64c, the gap is narrow, so the movable side reduced diameter part 62b and the nozzle part side reduced diameter part. The exhaust gas hardly flows into the space between 64c. Accordingly, the exhaust gas flowing into the nozzle inner passage 64a from the independent exhaust passage 52 passes through the nozzle inner passage 64a without flowing out of the nozzle portion 64 from the opening 64d, and flows downstream from the downstream end of the nozzle inner passage 64a. To go.

  On the other hand, as shown in FIGS. 8 and 9, when the movable part 62 is displaced downstream from the most upstream position and reaches the most downstream position, the movable side reduced diameter part 62b is moved from the nozzle part side reduced diameter part 64c. Largely spaced downstream. Accordingly, a passage is formed between the reduced diameter portions 62b and 64c, and each opening 64d is opened. For this reason, in a state where the movable portion 62 is displaced to the most downstream position, a part of the exhaust gas flowing from the independent exhaust passage 52 into the nozzle inner passage 64a is transferred to the movable side reduced diameter portion 62b and the nozzle portion side reduced diameter portion 64c. It flows downstream through a passage formed between them (hereinafter referred to as “external passage 64e”). That is, as indicated by an arrow in FIG. 9, the exhaust gas flowing from the independent exhaust passage 52 into the nozzle inner passage 64a passes through the external passage 64e in addition to the nozzle inner passage 64a.

  As described above, in the present embodiment, the position of the movable portion 62 is displaced to the most upstream position and the downstream position, so that the exhaust gas flowing into the nozzle internal passage 64a from the independent exhaust passage 52 can be reduced. The passages that pass through are switched to only the nozzle inner passage 64a, the nozzle inner passage 64a, and the external passage 64e, thereby switching the passage area of the passage through which the exhaust gas passes. That is, by setting the position of the movable portion 62 to the most upstream position, the flow passage area of the passage through which the exhaust gas passes is minimized, and the position of the movable portion 62 is further downstream than the most upstream position. This channel area is made larger than the minimum. And the speed of the exhaust discharged downstream from the nozzle passage 64a is switched along with the switching of the flow path area. Specifically, when the position of the movable portion 62 is the most upstream position and the passage area of the passage through which the exhaust gas passes is minimized, the speed at which this exhaust is discharged downstream from the nozzle inner passage 64a is Get higher. On the other hand, when the position of the movable portion 62 is the most downstream position and the flow passage area of the passage through which the exhaust passes is maximized, the speed at which the exhaust gas is discharged from the nozzle inner passage 64a to the downstream side can be kept low. .

  Here, each intra-nozzle passage 64a communicates with each independent exhaust passage 52 individually. Therefore, the exhaust in the nozzle passage 64a flows down without mixing with the exhaust in the other nozzle passage 64a. On the other hand, the space between the movable portion-side reduced diameter portion and the nozzle portion-side reduced diameter portion communicates with the entire circumference around the central axis X1. However, since the opening 64d is opened in the downstream direction as described above, the exhaust gas that has passed through the independent exhaust passage 52 and the nozzle inner passage 64a in the external passage 64e is also another independent exhaust passage 52, 64a. It flows down independently with little mixing with the exhaust that passed through.

  The movable straight portion 62c is discharged from each independent exhaust passage 52 and exhaust gas that has independently passed through the nozzle inner passage 64a or the nozzle inner passage 64a and the outer passage 64e, that is, exhausted from the cylinders 12a to 12d. This is where the exhaust gas merges.

  The movable straight portion 62c has a constant flow path area in the downstream portion so that exhausts discharged from the cylinders 12a to 2d merge, mix well, and are well rectified.

  In the present embodiment, the upstream portion of the movable straight portion 62c is configured such that the flow path area becomes smaller toward the downstream side, while the downstream portion extends downstream with a constant flow path area. Specifically, the upstream side portion of the movable side straight portion 62c has a substantially truncated cone shape whose diameter decreases toward the downstream side about the central axis X2, and the downstream side portion of the movable side straight portion 62c is It has a cylindrical shape with a constant diameter. The upstream portion of the movable straight portion 62c extends continuously from the downstream end of the movable reduced diameter portion 62b, and the downstream portion of the movable straight portion 62c has a constant flow area from the downstream end of the upstream portion. It extends in.

  A flange portion 62e that protrudes radially outward from the outer peripheral surface is provided on the outer peripheral surface of the downstream portion of the movable straight portion 62c. The flange part 62e is formed integrally with the movable side straight part 62c.

<Configuration of diffuser unit 63>
The diffuser portion 63 is a cylindrical portion that is configured so that the flow passage area increases toward the downstream side. Specifically, the upstream portion 63a of the diffuser portion 63 has a cylindrical shape with a constant diameter in the upstream and downstream directions. The portion 63b on the downstream side of the upstream portion 63a has a substantially truncated cone shape whose diameter increases toward the downstream side.

  Inside the diffuser portion 63, the downstream end portion of the movable straight portion 62c is inserted from the upstream side. The inner diameter of the upstream portion 63a of the diffuser portion 63 is set to be larger than the outer diameter of the downstream end portion of the movable-side straight portion 62c. Specifically, it is movable when the movable part 62 is in the most upstream position and in the most downstream position (see FIGS. 6 to 9, 10 (a), (c), 11 (a), (c)). The outer peripheral surface of the downstream end portion of the side straight portion 62 c is separated from the inner peripheral surface of the upstream portion 63 a of the diffuser portion 63, while the movable side straight portion 62 c is closest to the pivot support portion 82 as the eccentric cam 80 rotates. The upstream side portion of the diffuser portion 63 so that the outer peripheral surface of the downstream end portion of the movable side straight portion 62c abuts on the inner peripheral surface of the upstream portion 63a of the diffuser portion 63 (see FIG. 10B). The inner diameter of 63a is set. When the movable portion 62 is displaced, the downstream end portion of the movable straight portion 62 c moves in the radial direction of the diffuser portion 63 while moving in the upstream and downstream directions along the axial direction of the diffuser portion 63 in the diffuser portion 63. . The diffuser part 63 is fixed to the outer shell 61. In the present embodiment, the diffuser portion 63 is welded to the outer shell 61.

<Configuration of outer shell 61>
The outer shell 61 includes a nozzle part 64, a movable part 62, a diffuser part 63, an upstream buffer member 65, a downstream buffer member 66, an operation part 75, an operated part 92, an eccentric cam 80, an outer ring part 81a, and a swinging part. This is a tubular member that houses the arms 81b and 81c and the pivot portion 81d. As shown in FIGS. 6 and 7, the outer shell 61 includes a first portion 61a, a second portion 61b, a third portion 61c, and a fourth portion 61d in order from the upstream.

  The first portion 61a surrounds (covers) the upstream portion of the movable portion 62, the nozzle portion 64, and the upstream buffer member 65, and extends in a cylindrical shape toward the downstream side while maintaining the same diameter in the upstream and downstream directions. ing.

  The second portion 61b surrounds the upstream side portions of the movable-side reduced diameter portion 62b, the raised portion 62d, the downstream-side buffer member 66, and the straight portion 62c of the movable portion 62, and extends downstream. The second portion 61b is configured to incline toward the central axis X2 as it goes downstream, and is formed in a truncated cone shape that decreases in diameter toward the downstream side.

  A bulging portion 61e bulging outward is formed at the downstream end of the second portion 61b in the upstream / downstream direction over the entire circumferential direction. The bulging part 61e is formed over a predetermined length in the upstream / downstream direction. Specifically, the length of the bulging portion 61e in the upstream / downstream direction is substantially the same as the length of the downstream buffer member 66 in the upstream / downstream direction. The inner peripheral surface of the bulging portion 61e is formed in a shape (circular arc shape) along the outer peripheral surface of the downstream buffer member 66. Specifically, as shown in FIG. 9, the inner peripheral surface of the bulging portion 61 e is a part of the second spherical surface C <b> 2 having a radius R <b> 2 centered on the point P <b> 2 on the central axis X <b> 3 of the outer shell 61. It is formed to make. That is, when the bulging portion 61e is cut along a plane passing through the central axis X3, the inner edge (edge on the central axis X3 side) of the cut surface becomes an arc shape. The point P2 is located on the upstream side of the bulging portion 61e on the central axis X3.

  The third portion 61c surrounds the cylindrical downstream portion of the movable straight portion 62c, the operating portion 75, the operated portion 92, the eccentric cam 80, the outer ring portion 81a, the swinging arms 81b and 81c, and the pivot portion 81d. Yes.

  The third portion 61c includes a cover portion 61f that accommodates the eccentric cam 80 and the outer ring portion 81a, and a pivot support portion 82 that supports the pivot portion 81d.

  The cover portion 61f is a portion that bulges radially outward on the downstream side of the bulging portion 61e in the outer shell 61. The cover portion 61f rotatably supports the shaft 73A via a cylindrical bush (not shown).

  The pivot support portion 82 is a portion that bulges outwardly in the radial direction on the downstream side of the bulging portion 61 e in the outer shell 61. The pivot support portion 82 is formed on the side opposite to the cover portion 61 f in the outer shell 61 in the radial direction. The pivot support portion 82 has a cylindrical slide support surface 82a (see FIGS. 6 to 10 and 12) extending radially outward on the inside thereof. The slide support surface 82a supports a spherical pivot portion 81d, which will be described later, so as to be slidable in a direction A (see FIG. 10) connecting the pivot portion 81d and the shaft 73A.

  The fourth portion 61 d surrounds the diffuser portion 63 and is formed in a substantially truncated cone shape along the outer shape of the diffuser portion 63. The diffuser portion 63 is fixed to the fourth portion 61d.

<Configuration of moving mechanism 90A>
A moving mechanism 90A for displacing the movable part 62 will be described.

  As shown in FIGS. 2 and 3, the moving mechanism 90 </ b> A in this embodiment includes an actuator 70, a lever portion 94, a shaft 73 </ b> A (corresponding to a “camshaft” of the present invention), and swing arms 81 a and 81 b. (Refer to FIGS. 6 to 10 and 12), an operating portion 75, an operated portion 92, an eccentric cam 80, a pivot portion 81d, a pivot support portion 82, and an outer ring portion 81a. The outer ring portion 81a, the swing arms 81b and 81c, the operation portion 75, and the pivot portion 81d are integrally formed.

  The lever portion 94 is a plate-like member that connects the rod 72 and the shaft 73. One end portion of the lever portion 94 is swingably connected to the tip portion of the rod 72 (the end portion on the side opposite to the actuator body 71). As the rod 72 is displaced (advanced and retracted), the lever portion 94 swings along the upstream / downstream direction about the shaft 73A.

  The shaft 73 </ b> A is a cylindrical member, and extends from the lever portion 94 toward the outer shell 61. The end of the shaft 73 </ b> A on the lever portion 94 side is fixed to the lever portion 94. As the lever portion 94 swings, the shaft 73A rotates (rotates) around its axis Q (see FIGS. 6 and 8).

  As shown in FIGS. 6 to 10 and 12, the eccentric cam 80 is a disc-shaped cam provided at a position radially outside the movable side straight portion 62 c of the movable portion 62, and is located at the eccentric position. The shaft 73A is fixed, and rotates with the rotation of the shaft 73A. A radial center C of the eccentric cam 80 (see FIGS. 6, 8, and 11) is a direction A that connects the axis Q of the shaft 73A and the pivot portion 81d while being displaced in the upstream and downstream direction as the shaft 73A rotates. (Refer to FIG. 10).

  Specifically, in a state where the center C in the radial direction of the eccentric cam 80 is located upstream of the axis Q of the shaft 73A (see FIGS. 6, 7, 10 (a), 11 (a)), the shaft 73A 6 rotates counterclockwise (counterclockwise) in FIG. 6, and the center C of the eccentric cam 80 is aligned at the same position in the upstream / downstream direction with respect to the axis Q of the shaft 73A (FIG. 10B). , 11 (b)), the state shifts to a state where the center C of the eccentric cam 80 is located downstream of the shaft center Q of the shaft 73A (see FIGS. 8, 9, 10 (c), 11 (c)). To do.

  In a state where the center C in the radial direction of the eccentric cam 80 is located downstream of the axis Q of the shaft 73A (see FIGS. 8, 9, 10 (c), 11 (c)), the shaft 73A is in FIG. In the clockwise direction (clockwise direction), the center C of the eccentric cam 80 is aligned at the same position in the upstream and downstream directions with respect to the axis Q of the shaft 73A (FIGS. 10B and 11B). )), The center C of the eccentric cam 80 transitions to a state (see FIGS. 6, 7, 10 (a), 11 (a)) located upstream of the axis Q of the shaft 73A.

  In a state where the center C of the eccentric cam 80 is located on the most upstream side (see FIGS. 6 and 7), the axis Q of the shaft 73A passes through the center C of the eccentric cam 80 and extends along the upstream and downstream directions. It is located in the vicinity of X4 (see FIG. 11A). That is, the distance S3 between the reference line X4 and the axis Q of the shaft 73A is a value near zero. A straight line X5 in FIG. 11A is a line that passes through the axis Q of the shaft 73A and is parallel to the reference line X4. Further, in FIG. 11A, the distance S3 is shown to be about the radius of the shaft 73A for easy understanding of the drawing, but actually, the distance S3 is set smaller than the radius of the shaft 73A.

  In this state, the position of the movable portion 62 is the most upstream position (see FIGS. 6 and 7), and as a result, the passage through which the exhaust gas flowing into the nozzle passage 64a from the independent exhaust passage 52 passes is only the nozzle passage 64a. It becomes. As a result, the passage area of the passage through which the exhaust gas passes is minimized.

  On the other hand, in a state where the center C of the eccentric cam 80 is located on the most downstream side (see FIGS. 8 and 9), the shaft center Q of the shaft 73A passes through the center C of the eccentric cam 80 and extends in the upstream / downstream direction. It is located in the vicinity of the reference line X4 (see FIG. 11C). That is, the distance S4 between the reference line X4 and the axis Q of the shaft 73A is a value near zero. A straight line X5 in FIG. 11C is a line that passes through the axis Q of the shaft 73A and is parallel to the reference line X4. Further, in FIG. 11C, the distance S4 is shown to be about the radius of the shaft 73A in order to make the drawing easier to see, but actually, the distance S4 is set smaller than the radius of the shaft 73A.

  In this state, the position of the slide portion 62 is the most downstream position (see FIGS. 8 and 9), whereby the passage through which the exhaust gas flowing from the independent exhaust passage 52 into the nozzle passage 64a passes is the nozzle passage 64a and It becomes the external passage 64e. As a result, the flow passage area of the passage through which the exhaust gas passes becomes larger than in the case of FIGS.

  As shown in FIGS. 6 to 10 and 12, the outer ring portion 81 a (corresponding to the “displacement portion” of the present invention) is an annular member that is rotatably fitted on the outer periphery of the eccentric cam 80. As the eccentric cam 80 rotates, the outer ring portion 81a is displaced in the direction A (see FIG. 10) connecting the shaft center Q of the shaft 73A and the pivot portion 81d while being displaced in the upstream / downstream direction. That is, the outer ring portion 81 a is displaced in accordance with the movement of the center C of the eccentric cam 80. In the state shown in FIG. 10B, that is, when the movable portion 62 is at the center position between the most upstream position and the most downstream position, the outer ring portion 81 a and the movable side straight portion 62 c are closest to the pivot support portion 82. To do.

  The swing arms 81b and 81c are rod-shaped members corresponding to the “connecting portion” of the present invention. 6 to 10 and 12, the swing arm 81b connects the outer ring portion 81a and the operation portion 75, and the swing arm 81c connects the operation portion 75 and the pivot portion 81d. The swing arm 81b and the swing arm 81c each extend in a direction connecting the outer ring portion 81a and the pivot portion 81d, and these are arranged on the same straight line.

  As the shaft 73A rotates, the swing arms 81b and 81c swing along the upstream / downstream direction with the pivot portion 81d as the center (see FIGS. 6 to 10). That is, the swing arms 81b and 81c swing around the swing center N with the center N of the pivot portion 81d as the swing center.

  7 and 9, a point K is an intersection of a straight line L1 connecting the axis Q of the shaft 73A and the center N of the pivot portion 81d and the central axes X1 and X2, and a point M is the eccentric cam 80. This is an intersection of a straight line L2 connecting the center C and the center N of the pivot part 81d and the central axes X1 and X2.

  The pivot portion 81d is a spherical portion provided at the tip of the swing arm 81c. The pivot portion 81d slides and displaces in a direction A (see FIG. 10) connecting the pivot portion 81d and the shaft 73A while contacting the slide support surface 82a of the slide support portion 82.

  In the example shown in FIGS. 2 and 3, the actuator 70 is a direct-acting diaphragm type actuator. The actuator 70 includes a rod 72 and an actuator main body 71 that incorporates a diaphragm (not shown) and reciprocates the rod 72. The rod 72 extends from the actuator body 71 in a direction inclined with respect to the central axis X3 of the outer shell 61. When the actuator main body 71 is operated, the rod 72 is linearly displaced in a direction in which it is in contact with or separated from the actuator main body 71 (advance toward the downstream side and retreat toward the upstream side).

  As shown in FIG. 2, one end portion (end portion on the movable portion 62 side) of the lever portion 94 is swingably connected to the tip portion of the rod 72, and the other end portion (counter-movable portion 62) of the lever portion 94. Side end) is fixed to the shaft 73A. The connecting portion between the lever portion 94 and the rod 72 is located closer to the central axis X3 side of the outer shell 61 than the connecting portion (fixed portion) between the lever portion 94 and the shaft 73A.

  In the present embodiment, the eccentric cam 80 rotates with the rotation of the shaft 73A, so that the position of the slide portion 62 is the most upstream position (see FIGS. 6 and 7) and the downstream position (see FIG. 8). , 9), thereby switching the flow path area of the passage through which the exhaust gas passes.

  The rod 72, the lever portion 94, and the shaft 73A constitute a link mechanism that converts the linear motion of the rod 72 into the rotational motion of the shaft 73A. The eccentric cam 80, the outer ring portion 81a, the swinging arms 81a and 81b, the pivot portion 81d, The pivot support portion 82 constitutes a cam mechanism for converting the rotational motion of the shaft 73A into the swing motion of the swing arms 81a and 81b.

  6-9, the operation part 75 is provided between the swing arm 81b and the swing arm 81c. The operation unit 75 is formed of a truncated cone-shaped peripheral wall whose diameter decreases toward the downstream side, and the outer peripheral surface and the inner peripheral surface of the peripheral wall are curved in a spherical shape. The upstream end portion of the operation portion 75 is formed integrally with the end portion on the movable portion 62 side of the swing arm 81b and the end portion on the movable portion 62 side of the swing arm 81c. The thickness of the operation unit 75 is constant throughout.

  The operating portion 75 swings around the center N of the pivot portion 81d along with the swing arms 81b and 81c along the upstream / downstream direction.

  When the operating portion 75 is viewed from the upstream side or the downstream side, the operating portion 75 has a ring shape that has an inner diameter larger than the outer diameter of the movable straight portion 62c and surrounds the movable straight portion 62c. An insertion hole 75a (see FIGS. 6 and 8) through which the movable-side straight portion 62c is inserted is formed at the center of the operation portion 75. The diameter of the insertion hole 75a is larger than the outer diameter of the movable straight portion 62c and smaller than the outer diameter of the first operated portion 78 described later.

  The operation unit 75 has a first surface that is an inner peripheral surface of the operation unit 75 on the upstream side, and a second surface that is an outer peripheral surface of the operation unit 75 on the downstream side.

  The first surface of the operation unit 75 is a concave surface having an arcuate cross section. Specifically, the first surface of the operation unit 75 is configured by a part of a third spherical surface C3 having a radius R3 with the point P3 on the central axis X2 of the movable unit 62 as the center.

  A center point P3 when the movable portion 62 is at the most upstream position of the movable region (hereinafter referred to as “center point P3 of the most upstream position”) and a position when the movable portion 62 is at the most downstream position of the movable region. The center point P3 (hereinafter referred to as “the center point P3 at the most downstream position”) is a straight line L1 (a perpendicular line extending from the shaft 73A to the center axis X2) connecting the axis Q of the shaft 73A and the center N of the pivot portion 81d. ) And the center axis X2 of the movable portion 62 is located upstream of the intersection K (see FIGS. 7 and 9).

  When the movable portion 62 is at the most upstream position of the movable region, the intersection point M is on the central axis X2 of the movable portion 62, the central axis X1 of the nozzle portion 64, and the central axis X3 of the outer shell 61 and from the intersection point K. Located upstream (see FIG. 7). On the other hand, when the movable portion 62 is at the most downstream position of the movable region, the intersection point M is on the central axis X2 of the movable portion 62, the central axis X1 of the nozzle portion 64, and the central axis X3 of the outer shell 61 and the intersection point K. It is located on the downstream side (see FIG. 9).

  The distance between the intersection K and the intersection M when the movable part 62 is at the most upstream position (see FIG. 7) is the distance between the intersection K and the intersection M when the movable part 62 is at the most downstream position (see FIG. 9). be equivalent to.

  The second surface of the operation unit 75 is a convex surface having an arcuate cross section. Specifically, the second surface of the operation unit 75 is configured by a part of a fourth spherical surface C4 having a radius R4 with the center point P3 of the third spherical surface C3 as the center.

  6-9, the to-be-operated part 92 is provided in the outer peripheral surface of the downstream part of the movable side straight part 62c. The operated portion 92 includes a groove portion 93 (see FIGS. 7 and 9) having an inner wall surface that supports the operating portion 75 from both sides in the upstream and downstream directions in a slidable manner. The inner wall surface of the groove 93 is formed by a convex surface along the first surface of the operation unit 75 and a concave surface along the second surface of the operation unit 75.

  The operated portion 92 includes a first operated portion 78 having the convex surface, and a second operated portion 76 having the concave surface and separate from the first operated portion 78. The groove portion 93 is formed between the convex surface of the first operated portion 78 and the concave surface of the second operated portion 76. The width of the groove 93 (the interval between the convex surface and the concave surface) is substantially the same as the thickness of the operation unit 75. The 1st to-be-operated part 78 and the 2nd to-be-operated part 76 are formed in the ring shape along the perimeter of the outer peripheral surface of the movable side straight part 62c.

  The first operated portion 78 is disposed on the upstream side of the second operated portion 76. The 1st to-be-operated part 78 is arrange | positioned so that the convex surface may face the downstream. The upstream surface of the first operated portion 78 is in contact with the downstream surface of the flange portion 62 e of the movable portion 62. The first operated portion 78 can be made of the same material as that of the upstream buffer member 65.

  The convex surface of the first operated portion 78 has an arcuate cross section. Specifically, the convex surface of the first operated portion 78 is constituted by a part of a third spherical surface C3 (which may be a spherical surface having a radius slightly smaller than the radius R3). That is, the convex surface of the first operated portion 78 is along the first surface of the operating portion 75 and is in contact with the first surface of the operating portion 75. The first surface of the operation unit 75 is slidable with respect to the convex surface of the first operated unit 78.

  The second operated portion 76 is arranged such that the concave surface faces the upstream side. The second operated portion 76 is a cylindrical fixed portion 76b fixed to the outer peripheral surface of the movable straight portion 62c, and extends from the upstream end of the fixed portion 76b to the upstream side to support the second surface of the operating portion 75. Supporting part 76a. The support portion 76a is a frustoconical peripheral wall whose diameter increases toward the upstream side. The upstream surface of the support portion 76 a is the concave surface of the second operated portion 76.

  The concave surface of the second operated portion 76 has an arcuate cross section. Specifically, the concave surface of the second operated portion 76 is constituted by a part of a fourth spherical surface C4 (a spherical surface having a radius slightly larger than the radius R4). That is, the concave surface of the second operated portion 76 is along the second surface of the operating portion 75 and is in contact with the second surface of the operating portion 75. The second surface of the operation unit 75 is slidable with respect to the convex surface of the second operated unit 76.

  In the moving mechanism 90A configured as described above, when the rod 72 is displaced by the drive of the actuator body 71, the lever portion 94 swings around the shaft 73A, and accordingly, the shaft 73A is centered on the axis Q. Rotate (turn). As the shaft 73A rotates, the eccentric cam 80 rotates and the outer ring portion 81a is displaced in the upstream and downstream direction. As a result, the swing arms 81b and 81c and the operation portion 75 swing around the pivot portion 81d. As the operating unit 75 swings, the operated unit 92 displaces the movable unit 62 in the upstream / downstream direction while sliding the operating unit 75 in the groove 93 (see FIGS. 7 and 9).

  Next, the force which acts on the structural member of the moving mechanism 90A will be described with reference to FIGS. 11A and 12 show the state of the eccentric cam 80 when the movable portion 62 is at the most upstream position of the movable region, and FIG. 11B shows the movable portion 62 at the middle position of the movable region. FIG. 11C shows the state of the eccentric cam 80 when the movable portion 62 is at the most downstream position of the movable region. In FIG. 12, it is assumed that the forces are balanced in the entire moving mechanism 90A.

  Inside the movable part 62, exhaust gas flows toward the downstream side. For this reason, as shown in FIG. 12, the movable portion 62 receives a pressing force F <b> 1 in the direction toward the downstream side from the exhaust gas, and the pressing force F <b> 1 is transmitted to the operating portion 75 via the operated portion 92. A part of the force F6 of the pressing force F1 received by the operation unit 75 is transmitted to the outer ring portion 81a via the swing arm 81b, and a force F4 obtained by subtracting the force F6 from the force F1 is transmitted via the swing arm 81c. It is transmitted to the pivot part 81d. That is, the magnitude of the force F1 is equal to the sum of the magnitude of the force F4 and the magnitude of the force F6. Then, a force F6 directed in the downstream direction is transmitted from the outer ring portion 81a to the eccentric cam 80, and a force F4 directed in the downstream direction is transmitted from the pivot portion 81d to the pivot support portion 82 (see FIG. 12). .

  The eccentric cam 80 that receives the force F6 from the outer ring portion 81a applies a force F2 (reaction force) directed in the upstream direction to the outer ring portion 81a (see FIGS. 11A and 12). The force F2 is a force component in the clockwise direction in FIGS. 11A and 12 that opposes the force with which the exhaust gas tries to rotate the eccentric cam 80 (hereinafter referred to as “cam rotational force due to exhaust gas”). ) F22 and a component force (force toward the upstream side) f21 that opposes the force of the exhaust gas pressing the shaft 73A downstream. The component force f22 is a force obtained from the driving force F3 of the actuator 70 (see FIG. 12). A straight line L3 in FIGS. 11 and 12 is an action line of the force f21, and is a straight line passing through the action point of the force f21 and the axis Q of the shaft 73A. The straight line L4 is a line of action of the force f22 and is a straight line parallel to the direction in which the rod 72 of the actuator 70 advances and retreats.

  In order to apply the component force f22 to the eccentric cam 80, the actuator 70 may pull the rod 72 with a force F3 having the same direction as the component force f22 and a magnitude based on the component force f22. The actuator main body 71 of the actuator 70 can hold the position in the upstream / downstream direction of the movable portion 62 by pulling the rod 72 with the force F3. Note that the force f31 in FIG. 12 is a component force in the upstream and downstream direction of the force F3, and the force f32 is a component force in a direction parallel to the straight line L3.

  As can be seen from FIGS. 11A to 11C, in the state shown in FIG. 11A, the component force f22 is much smaller than in the states shown in FIGS. 11B and 11C. Yes. This is because the cam rotation force by the exhaust gas (the same force as the component force f22 and the opposite direction force) is reduced between the eccentric cam 80 and the outer ring portion 81a. This is because it is most reduced when it is at the most upstream position of the movable region (see FIG. 11A). That is, the smaller the angle θ formed by the force F6 and the straight line L3 at the point of action of the force F6 (in FIG. 11, the upstream end portion of the eccentric cam 80), in other words, the smaller the distance S3, Becomes smaller. From this, it can be seen that the movable portion 62 can be kept in the most upstream position only by generating a small tensile force F3 in the actuator 70.

  On the other hand, as shown in FIG. 13, when the lever portion 94 is fixed to the swing arm 74 via a shaft 73 (supported rotatably by an outer shell not shown), Since the force by which the gas tries to rotate the shaft 73 is not reduced between the swing arm 74 and the lever portion 94, the actuator 70 generates a driving force (tensile force) F7 larger than the force F3 in this embodiment. It is necessary to let A force f71 in FIG. 13 is a component force in the upstream and downstream direction of the force F7, and a force f72 is a component force in the direction along the lever portion 94 of the force F7.

<Control system configuration>
Next, a control system of the exhaust device 100 according to the present embodiment will be described. Each part of the exhaust device 100 of this embodiment is centrally controlled by an ECU (Electronic Control Unit) (not shown). The ECU is a microprocessor that includes a CPU, a ROM, a RAM, and the like.

  The actuator body 71 is ON / OFF controlled by the ECU so that the position of the rod 72 is switched between two positions, a first position and a second position. Accordingly, the movable part 62 is at its maximum position. Switching is possible between two positions, an upstream position and a most downstream position. For example, when the actuator 70 is turned on, the movable portion 62 is at the most upstream position, and when it is turned off, the movable portion 62 is at the most downstream position.

  This will be specifically described below. The ECU inputs the driving state of the vehicle from a sensor (not shown) that detects the driving state (driving region) of the vehicle, performs various determinations and calculations based on the driving state, and controls each part of the exhaust device 100. Control.

  In the present embodiment, as shown in FIG. 14, as operating regions, a low-speed and high-load region (first region) A1 where the engine speed is low and the engine load is high, and a low-speed and low-load region where the engine speed is low and the engine load is low. (Second area) A2 and a high speed area (third area) A3 where the engine speed is high and the engine load is high are set.

  Hereinafter, the control content implemented in each operation area | region is demonstrated.

(Control in the low speed and high load area A1)
In the low speed and high load region A1, the actuator 70 is controlled by the ECU so that the movable portion 62 is displaced to the most upstream position. Specifically, in the low speed and high load region A1, the ECU performs control to turn on the actuator 70.

  This control is performed mainly for the purpose of enhancing the ejector effect and promoting scavenging in each of the cylinders 12a to 12d by the ejector effect to ensure engine torque.

(Control in low speed and low load area A2)
In the low speed and low load region A2, the actuator 70 is controlled by the ECU so that the movable portion 62 is displaced to the most downstream position. Specifically, in the low speed and low load region A2, the ECU performs control to turn off the actuator 70.

  This control mainly secures the amount of residual gas in the cylinders 12a to 12d, suppresses the pumping loss of the intake air, suppresses the combustion temperature, and suppresses the increase of the cooling loss, thereby achieving an appropriate engine torque. It is implemented for the purpose of ensuring.

(Control in high speed area A3)
In the high speed region A3, the actuator 70 is controlled by the ECU so that the movable portion 62 is displaced to the most downstream position. Specifically, in the high speed region A3, the ECU performs control to turn off the actuator 70.

  This control is mainly performed for the purpose of keeping the back pressure low, thereby improving the scavenging performance and ensuring high engine torque.

  As described above, according to the present embodiment, the driving force (tensile force) required for the actuator 70 (direct acting actuator) to maintain the state in which the movable portion 62 is displaced upstream is reduced. Accordingly, the actuator 70 can be reduced in size. More specifically, in order to maintain the state where the movable portion 62 is displaced upstream (the state where the flow path area of the movable-side reduced diameter portion 62b is reduced), the movable portion 62 is moved downstream by the pressure of the exhaust gas. In order not to displace, it is necessary to cause the actuator 70 to generate a driving force (tensile force) F3 in a direction that displaces the movable portion 62 upstream. In this embodiment, since the eccentric cam 80 and the outer ring portion 81a that is displaced in the upstream / downstream direction with the rotation of the eccentric cam 80 are interposed between the actuator 70 and the movable portion 62, the cam rotation by the exhaust gas is performed. The force is reduced between the eccentric cam 80 and the outer ring portion 81a, whereby the driving force F3 required for the actuator 70 to counter the cam rotational force caused by the exhaust gas is reduced.

  In addition, according to the present embodiment, the force that the exhaust gas presses the movable portion 62 downstream is transmitted to both the pivot support portion 82 and the eccentric cam 80, so that the pressing force is eccentric with the pivot support portion 82. Distributed to the cam 80 (force F4 and force F6). Thereby, the cam rotational force by exhaust gas is reduced, and as a result, the driving force F3 required for the actuator 70 can be reduced.

  Further, according to the present embodiment, when the movable portion 62 is at the most upstream position in the movable region, the shaft center Q of the shaft 73A passes through the radial center C of the eccentric cam 80 and in the upstream / downstream direction. Since it is located in the vicinity of the reference line X4 along, the cam rotational force due to the exhaust gas has a magnitude near zero. Thereby, the driving force F3 (refer FIG. 12) required for the actuator 70 can be reduced significantly.

  Further, according to the present embodiment, the pivot support portion 82 supports the pivot portion 81d so as to be slidable in the direction A (see FIG. 10) connecting the pivot portion 81d and the shaft 73A. Can be smoothly displaced in the upstream and downstream directions.

  Further, according to the present embodiment, the first surface and the second surface of the operation portion 75 are supported by the inner wall surface of the groove portion 93 of the operated portion 92 with a wide contact area from both sides in the upstream and downstream directions. The occurrence of galling, sticking, and excessive wear due to the contact of the portion 75 with the operated portion 92 is suppressed, rattling is less likely to occur, and the generation of contact sound is also suppressed.

  In the above-described embodiment, all the cylinders 12a to 12d are connected to the independent exhaust passages 52 independently (each individually), whereby the number of independent exhaust passages 52 connected to the engine 1 is four. However, it is not limited to this. For example, among the cylinders 12, the first cylinder 12a and the fourth cylinder 12d are independently connected to the independent exhaust passages 52, 52, while the exhaust strokes are not adjacent to each other and the second cylinder 12b does not have a continuous exhaust sequence. The third cylinder 12c may be connected to one independent exhaust passage 52 that is bifurcated in the middle. Specifically, the independent exhaust passage 52 connected to the second cylinder 12b and the third cylinder 12c branches into two passages from the downstream side to the upstream side in the middle portion, and one of the branch passages The second cylinder 12b may be connected to the other, and the third cylinder 12c may be connected to the other branch passage. By adopting such a configuration, the number of independent exhaust passages 52 connected to the engine 1 is three, and the structure of the exhaust device is simplified.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, about the structure similar to 1st Embodiment, the same referential mark is attached | subjected and the description is abbreviate | omitted.

  As shown in FIGS. 15 and 16, in the second embodiment, a slit portion 81e extending linearly along the longitudinal direction of the swing arm 81d is provided at the center of the swing arm 81d. The slit portion 81 e is a long hole that opens at least toward the movable portion 62. In the example shown in FIGS. 15 and 16, the slit portion 81 e opens toward the movable portion 62 and the non-movable portion 62. The swing arm 81d connects the outer ring portion 81a, the pivot portion 81d, and the slit portion 81e. The slit portion 81e corresponds to the “operation portion” of the present invention.

  Further, a protrusion 62f that protrudes from the outer peripheral surface toward the slit portion 81e is provided on the outer peripheral surface of the movable-side straight portion 62c. The protrusion 62f is slidably in contact with the inner wall surface of the slit 81e while being inserted into the slit 81e, and is slidable along the longitudinal direction in the slit 81e.

  In the second embodiment, as the shaft 73A rotates, the swing arm 81d swings along the upstream / downstream direction about the pivot portion 81d. And with this rocking | fluctuation, the projection part 62f slide-displaces the inside of the slit part 81e along the longitudinal direction. Since the projecting portion 62f receives a force in the upstream / downstream direction from the inner wall surface of the slit portion 81e from the swing arm 81d, the movable portion 62 is displaced in the upstream / downstream direction (see FIGS. 15 and 16).

  Also in the second embodiment, similarly to the first embodiment, it is possible to reduce the driving force required for the actuator and reduce the size of the actuator.

1 Engine 12a to 12d Cylinder 52a Independent exhaust passage 62 Movable part 62b Movable side reduced diameter part (inflow part)
62c Movable side straight part (aggregation part)
62f, 92 Operated portion 64 Nozzle portion 64a Nozzle passage 70 Actuator 73A Shaft (camshaft)
75, 81e Operation part 80 Eccentric cam 81a Outer ring part (displacement part)
81b, 81c Swing arm (connecting part)
81d Pivot part 82 Pivot support part 90A Movement mechanism 93 Groove part C Center of eccentric cam N Center of oscillation Q Center axis of shaft

Claims (5)

A plurality of independent exhaust passages that are independently connected to the plurality of cylinders of an engine having a plurality of cylinders, or independent exhaust passages that are branched in the middle and connected to a plurality of cylinders whose exhaust order is not continuous A nozzle portion extending from a plurality of independent exhaust passages and formed with a plurality of nozzle internal passages into which gas discharged from each of the independent exhaust passages independently flows;
An inflow portion into which the gas discharged from the nozzle passage flows in, and a collecting portion into which the gas that has passed through the inflow portion gathers, and the upstream and downstream of the gas flow on the downstream side of the nozzle portion in the gas flow direction A cylindrical movable portion that is provided so as to be displaceable in a direction, and that reduces the flow area of the inflow portion when displaced upstream and expands the flow area of the inflow portion when displaced downstream; ,
A moving mechanism for displacing the movable part in the upstream and downstream directions,
The moving mechanism is
An operation portion provided with a swing center at a position radially outside of the movable portion and swingable along the upstream and downstream directions;
An operated portion that is provided in the movable portion and displaces the movable portion in the upstream and downstream directions in accordance with the swinging of the operation portion;
An eccentric cam provided at a position radially outside of the movable portion;
An actuator for applying a rotational force to the eccentric cam;
A displacement portion that is displaced in the upstream / downstream direction along with the rotation of the eccentric cam;
A pivot portion disposed at the swing center;
A pivot support part for supporting the pivot part;
An exhaust system for a multi-cylinder engine, comprising: a connecting portion that connects the displacement portion, the pivot portion, and the operation portion. The actuator applies a rotational force to a camshaft fixed to the eccentric cam;
When the movable portion is at the most upstream position in the movable region, the camshaft has an axial center passing through the radial center of the eccentric cam and in the vicinity of a reference line along the upstream and downstream directions. The exhaust system for a multi-cylinder engine according to claim 1, wherein The actuator applies a rotational force to a camshaft fixed to the eccentric cam;
The exhaust device for a multi-cylinder engine according to claim 1 or 2, wherein the pivot support portion supports the pivot portion so as to be slidable in a direction connecting the pivot portion and the camshaft. The operating portion includes a first surface formed of a concave surface having an arc-shaped cross section on one side in the upstream / downstream direction, and a second surface formed of a convex surface having an arc-shaped cross section on the other side in the upstream / downstream direction,
The operated portion is provided on an outer peripheral portion of the movable portion, and has a convex surface along the first surface of the operating portion and a concave surface along the second surface of the operating portion. A groove portion having an inner wall surface that slidably supports the operation portion from both sides in the upstream / downstream direction, and the movable portion is slid in the groove portion while the operation portion is slid in the groove portion as the operation portion swings. The exhaust device for a multi-cylinder engine according to any one of claims 1 to 3, wherein the exhaust device is displaced in a downstream direction. The actuator includes a rod, and an actuator body that applies a rotational force to a camshaft fixed to the eccentric cam by reciprocating the rod.
The moving mechanism further includes a lever rotatably connected to the rod;
The exhaust device for a multi-cylinder engine according to any one of claims 1 to 4, wherein the camshaft is fixed at a position apart from a connecting portion of the lever and the rod in the lever.

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