JP5057103B2 - Valve gear - Google Patents

Description

  The present invention relates to a valve gear for an internal combustion engine.

  As an internal combustion engine, an engine having a plurality of intake valves and a plurality of exhaust valves is known in order to optimally set intake and exhaust efficiency. In addition, a mechanism is provided that can appropriately set the opening / closing timings of the intake valve and the exhaust valve by changing the phase in the rotational direction of the camshaft according to the operating state of the internal combustion engine, that is, for each rotational speed of the internal combustion engine. An internal combustion engine is known (for example, see Patent Document 1).

In recent years, in the situation where the opening and closing timings of both the multiple intake valves and multiple exhaust valves are set, high reproducibility can be achieved without complicating the mechanism by comprehensively considering the flow of intake air and the return of exhaust gas Therefore, it has been required to improve output, improve fuel consumption, and reduce pumping loss.
JP 2008-25428 A

  The present invention has been made in view of the above circumstances, and is capable of operating a valve so as to optimally maintain the flow of intake air and the return of exhaust gas with high reproducibility without complicating the mechanism. An object is to provide a valve device.

In order to achieve the above object, a valve operating apparatus according to a first aspect of the present invention includes a pair of intake valves, a pair of exhaust valves, a first camshaft and a second camshaft that are rotated in synchronization with the drive rotation of the crankshaft. A camshaft, first lift means for operating the one side intake valve and the one side exhaust valve in conjunction with rotation of the first camshaft, and the other side intake valve and the other side exhaust by rotating the second camshaft. Second lift means for operating the valve in conjunction with the lift , and the first lift means is provided on the first auxiliary camshaft to which the rotation of the first camshaft is transmitted, and on the first auxiliary camshaft. A first intake cam that lifts the one-side intake valve, and a first exhaust cam that is provided on the first auxiliary camshaft and lifts the one-side exhaust valve. The second lift means includes a second auxiliary camshaft to which the rotation of the second camshaft is transmitted, a second intake cam provided on the second auxiliary camshaft to lift the other intake valve, The second auxiliary camshaft is provided with a second exhaust cam that lifts the other side exhaust valve .

In the first aspect of the present invention, the one-side intake valve and the one-side exhaust valve are lifted together via the first lift means by the rotation of the first camshaft, and the other-side intake valve is rotated by the rotation of the second camshaft. And the other side exhaust valve is lifted in conjunction via the second lift means. Accordingly, for example, a large swirl flow can be formed in a state where the return of the intake air (mixture) and the exhaust does not interfere between the opposed intake valve and exhaust valve, or the one-side intake valve The lift state of multiple intake valves and multiple exhaust valves so that there is an overlap between the exhaust valve and the other exhaust valve so that the flow of intake (air mixture) and the return flow of exhaust can be in the same direction Can be set mechanically. As a result, the valve can be operated to optimally maintain the flow of intake air and the return of exhaust gas with high reproducibility without complicating the mechanism.
Then, the rotation of the first camshaft is transmitted to the first auxiliary camshaft, the first intake cam and the first exhaust cam lift the one side intake valve and the one side exhaust valve, and the second camshaft rotates the second camshaft. By transmitting to the auxiliary camshaft and lifting the other side intake valve and the other side exhaust valve by the second intake cam and the second exhaust cam, the machine can maintain the flow of intake air and the return of exhaust gas optimally. The valve can be operated automatically.

Also, a valve apparatus of the present invention according to claim 2, in the valve operating device according to claim 1, wherein the first camshaft and the second camshaft is arranged in parallel with each other in one direction, the The first auxiliary camshaft and the second auxiliary camshaft are arranged in parallel to each other in a direction intersecting the first camshaft and the second camshaft, and the rotation transmission of the first camshaft and the first auxiliary camshaft. And transmission means for transmitting rotation of the second camshaft and the second auxiliary camshaft, respectively.

In the present invention according to claim 2 , the first auxiliary camshaft and the second auxiliary camshaft, which are arranged in a direction intersecting the first camshaft and the second camshaft, are rotated via the transmission means, and a plurality of intake air is introduced. The valve and the plurality of exhaust valves can be lifted.

According to a third aspect of the present invention, in the valve gear of the second aspect , the transmission means is a screw gear. According to a fourth aspect of the present invention, in the valve gear of the third aspect, the transmission means is a worm and a worm wheel.

In the present invention according to claim 3 , the plurality of intake valves and the plurality of exhaust valves can be lifted via the screw gears that can set the reduction ratio to 1: 1. In the present invention according to claim 5, a plurality of intake valves and a plurality of exhaust valves can be lifted via a worm and a worm wheel that can set a large reduction ratio.

  As the transmission means, in addition to the worm and the worm wheel, it is possible to apply a helical bevel gear, a spiral hook, or the like.

A valve operating device according to a fifth aspect of the present invention is the valve operating device according to any one of the second to fourth aspects, wherein the first lift means and the second lift means are the pair. The lash adjuster provided corresponding to each of the intake valve and the pair of exhaust valves, and the lash adjuster are supported by one end as a fulcrum and swingably supported, the other end abuts the valve side, and the middle part is a cam. And an arm pushed by the.

In the present invention according to claim 5 , the plurality of intake valves and the plurality of exhaust valves can be lifted while the valve clearance is properly maintained by the lash adjuster.

According to a sixth aspect of the present invention, the valve gear of the present invention is the valve gear according to the fifth aspect , wherein the first cam phase change for arbitrarily changing the phase in the rotational direction of the first intake cam and the first exhaust cam. And a second cam phase changing means for arbitrarily changing the phase in the rotational direction of the second intake cam and the second exhaust cam.

In the present invention according to claim 6 , the lift timing of one intake valve, the exhaust valve, the other intake valve, and the exhaust valve can be continuously changed by the first cam phase changing means and the second cam phase changing means. it can.

  The valve operating apparatus of the present invention can operate the valve so as to optimally maintain the flow of intake air and the return of exhaust gas with high reproducibility without complicating the mechanism.

  FIG. 1 is an external view of a camshaft equipped with a valve gear according to an embodiment of the present invention, FIG. 2 is a plan view of a main part in FIG. 1, and FIG. 3 is a line III-III arrow in FIG. FIG. 4 is a view taken along the line IV-IV in FIG. 2, FIG. 5 is a time chart of valve operation, and FIG. 6 shows a flow state in the cylinder (combustion chamber). FIG. 7 shows a flow state in the cylinder (combustion chamber) in a state where the intake air and the exhaust gas interfere with each other. FIG. 8 shows the external appearance of the main part of a camshaft provided with a valve gear according to another embodiment of the present invention.

  The main part of the internal combustion engine provided with the valve operating device will be described with reference to FIGS.

  As shown in FIG. 1, on the cylinder head side, a first camshaft 1 and a second camshaft 2 are arranged in parallel with each other along the cylinder arrangement direction (in one direction). Sprockets 3 and 4 are provided at the end of the second camshaft 2. A timing chain 7 is wound around the sprocket 3, 4 and the sprocket 6 on the crankshaft 5 side, and the power of the crankshaft 5 is transmitted to the first camshaft 1 and the first camshaft via the timing chain 7 and the sprockets 3, 4. 2 is transmitted to the camshaft 2.

  Each cylinder of the internal combustion engine is provided with intake valves 13F and 13R and exhaust valves 15F and 15R. The intake valve 13F and exhaust valve 15F on the side of the sprocket 3 and 4 are used as one side intake valve and exhaust valve, respectively. The intake valve 13R and the exhaust valve 15R on the opposite side are the other intake valve and exhaust valve.

  A first lift means 11 is provided across the first camshaft 1, the intake valve 13F and the exhaust valve 15F, and the intake valve 13F and the exhaust valve 15F are set in a predetermined manner via the first lift means 11 by the rotation of the first camshaft 1. The lift operation is performed at the lift timing and the lift amount. A second lift means 12 is provided across the second camshaft 2, the intake valve 13R and the exhaust valve 15R, and the intake valve 13R and the exhaust valve 15R are connected via the second lift means 12 by the rotation of the second camshaft 2. The lift operation is performed at a predetermined lift time and lift amount.

  The sprocket 3 at the end of the first camshaft 1 is provided with first cam phase changing means 51 as first cam phase changing means. In the first cam phase changing means 51, a rotor member integrated with the first camshaft 1 is rotatably arranged on the sprocket 3, and the rotor member is rotated with respect to the sprocket 3 by, for example, hydraulic pressure, so that the sprocket 3 On the other hand, the phase of the rotation direction of the first camshaft 1 is changed, and the lift timing of the intake valve 13F and the exhaust valve 15F is continuously changed.

  The sprocket 4 at the end of the second camshaft 2 is provided with second cam phase changing means 52 as second cam phase changing means. In the second cam phase changing means 52, a rotor member integral with the second camshaft 2 is rotatably arranged on the sprocket 4, and the rotor member is rotated with respect to the sprocket 4 by, for example, hydraulic pressure. On the other hand, the phase of the rotation direction of the second camshaft 2 is changed, and the lift timing of the intake valve 13R and the exhaust valve 15R is continuously changed.

  The lift timing of the intake valve 13F, the exhaust valve 15F, the intake valve 13R, and the exhaust valve 15R is fixed to a predetermined state without providing the first cam phase changing means 51 and the second cam phase changing means 52. It is also possible to do.

  Based on FIGS. 2-4, the structure of the site | part of a cylinder head is demonstrated concretely. FIG. 3 is a sectional view of the intake valve 13R and the exhaust valve 15R, but the configurations of the intake valve 13F and the exhaust valve 15F are the same.

  A surface forming the upper wall of the combustion chamber 22 is formed on the lower surface of the cylinder head 21, and two intake openings 24 of the intake port 23 and two exhaust openings 26 of the exhaust port 25 are formed on the surface forming the upper wall. Is provided. The intake valve 13R is arranged to communicate and block the intake opening 24 and the combustion chamber 22, and the exhaust valve 15R is arranged to communicate and block the exhaust opening 26 and the combustion chamber 22.

  The intake valve 13R includes an umbrella portion 13a formed in accordance with the opening shape of the intake opening portion 24, and a stem portion 13b is provided at an upper portion of the central portion of the umbrella portion 13a. A cylindrical stem guide 27 is press-fitted into the cylinder head 21, and a stem portion 13b of the intake valve 13R is slidably supported by the stem guide 27.

  A disc-shaped retainer 29 is connected to the upper end of the stem portion 13b via a cotter 28, and a spring 31 is provided between the lower surface of the retainer 29 and the seat 30 on the cylinder head 21 side. That is, the stem portion 13 b is biased upward by the spring 31 via the retainer 29, and the intake valve 13 is biased in the valve closing direction (the direction in which the intake opening 24 and the combustion chamber 22 are blocked).

  A cylindrical valve lifter 14 is arranged on the upper portion of the stem portion 13b, and the inner side of the upper end surface of the valve lifter 14 is attached to the upper portion of the stem portion 13b, so that the outer side of the spring 31 is covered with the cylindrical surface of the valve lifter 14. Has been. A shim 32 is provided on the outer side (upper surface) of the upper end surface of the valve lifter 14, and a tip of an arm 56 described later is in contact with the upper surface of the shim 32.

  Similarly, the exhaust valve 15 includes an umbrella portion 15 a, a stem portion 15 b, and a valve lifter 16, and is supported by the cylinder head 21 with the same configuration as the intake valve 13. For this reason, the description which attaches | subjects the same code | symbol with respect to a supporting member, and overlaps is abbreviate | omitted.

  The intake valve 13 and the exhaust valve 15 are lifted by the first lift means 11 in conjunction with the one intake valve 13F and the exhaust valve 15F (one side intake valve, one side exhaust valve). The intake valve 13R and the exhaust valve 15R (the other side intake valve, the other side exhaust valve) are lifted together. The first lift means 11 and the second lift means 12 will be described.

  A first worm 41 is provided as a transmission means on the first camshaft 1 at a position corresponding to one of the intake valves 13F and the exhaust valve 15F. A first auxiliary camshaft 42 is rotatably supported on the cylinder head 21 side orthogonal to the first camshaft 1, and a first worm wheel 43 is provided as a transmission means at the base end portion of the first auxiliary camshaft 42. ing. The first worm wheel 43 meshes with the first worm 41 of the first camshaft 1, and the rotation of the first camshaft 1 is transmitted to the first auxiliary camshaft 42 via the first worm 41 and the first worm wheel 43. . The first auxiliary cam shaft 42 is provided with a first intake cam 45 and a second exhaust cam 46.

  The second camshaft 2 at a position corresponding to the other intake valve 13R and exhaust valve 15R is provided with a second worm 40 as a transmission means. A second auxiliary cam shaft 47 is rotatably supported on the cylinder head 21 side perpendicular to the second cam shaft 2, and a second worm wheel 48 is provided as a transmission means at the base end portion of the second auxiliary cam shaft 47. ing. The second worm wheel 48 meshes with the second worm 40 of the second cam shaft 2, and the rotation of the second cam shaft 2 is transmitted to the second auxiliary cam shaft 47 via the second worm 40 and the second worm wheel 48. . The second auxiliary cam shaft 47 is provided with a second intake cam 49 and a second exhaust cam 50.

  The cylinder head 21 includes lash adjusters 55 corresponding to the intake valves 13F and 13R and the exhaust valves 15F and 15R. The lash adjuster 55 and the valve lifters 14 of the intake valves 13F and 13R and the valve lifters 16 of the exhaust valves 15F and 15R are provided. An arm 56 is provided. One end of the arm 56 is supported by the cylinder head 21 by a lash adjuster 55 so as to be swingable, and the other end (tip) is in contact with the upper surface of the shim 32 of the valve lifter 14 or the valve lifter 16.

  A roller 57 is provided in the middle of the arm 56, and the first intake cam 45 and the second exhaust cam 46 (second intake cam 49 and second exhaust cam 50) are in contact with the roller 57. As the first auxiliary camshaft 42 (second auxiliary camshaft 47) rotates, the first intake cam 45 and the second exhaust cam 46 (second intake cam 49 and second exhaust cam 50) rotate, and the cam surface. Accordingly, the roller 57 is pushed and the arm 56 swings with the lash adjuster 55 as a fulcrum.

  When the arm 56 swings around the lash adjuster 55 as a fulcrum, the valve lifter 14 (valve lifter 16) is pushed on the other end side of the arm 56. Thereby, one intake valve 13F and the exhaust valve 15F and the other intake valve 13R and the exhaust valve 15R are lifted together.

  In the valve operating device described above, the power of the crankshaft 5 is transmitted to the first camshaft 1 and the second camshaft 2 to rotate. The rotation of the first camshaft 1 causes the first auxiliary camshaft 42 to rotate via the first worm 41 and the first worm wheel 43, and the rotation of the first intake cam 45 and the second exhaust cam 46 causes one intake valve to rotate. 13F and the exhaust valve 15F are lifted in conjunction with each other. At the same time, the rotation of the second camshaft 2 causes the second auxiliary camshaft 47 to rotate via the second worm 40 and the second worm wheel 48, and the rotation of the second intake cam 49 and the second exhaust cam 50 causes the other The intake valve 13R and the exhaust valve 15R are lifted together.

  Therefore, with high reproducibility by a mechanical mechanism without complicating the mechanism, one intake valve 13F and the exhaust valve 15F are operated in conjunction with each other, and the other intake valve 13R and the exhaust valve 15R are operated in conjunction with each other. The lift operation can be performed, and the valve can be operated to optimally maintain the flow of intake air and the return of exhaust gas.

  The state of the lift timing of the intake valves 13F and 13R and the exhaust valves 15F and 15R will be described based on FIG.

  By the rotation of the first auxiliary camshaft 42 and the second auxiliary camshaft 47, the one intake valve 13F and the exhaust valve 15F and the other intake valve 13R and the exhaust valve 15R are lifted together. The lift timing of the intake valves 13F, 13R and the exhaust valves 15F, 15R is set as follows, for example, depending on the state of the first intake cam 45, the second exhaust cam 46, the second intake cam 49, and the second exhaust cam 50. ing.

  That is, it is set so that no overlap occurs at the lift timing of one intake valve 13F and the exhaust valve 15F. The lift end timing of one intake valve 13F and the exhaust valve 15F (see the solid line in FIG. 5) is set earlier than the lift end timing of the other intake valve 13R and the exhaust valve 15R (see the dotted line in FIG. 5). Also, the lift timing of the other intake valve 13R and exhaust valve 15R is set so that no overlap occurs.

  The opening timing of one intake valve 13F is set earlier than the closing timing of the other exhaust valve 15R. That is, an overlap is formed between one intake valve 13F and the other exhaust valve 15R.

  In this state, by arbitrarily operating the first cam phase changing means 51 and the second cam phase changing means 52, the lift timing of one intake valve 13F and the exhaust valve 15F, and the other intake valve 13R and the exhaust valve 15R The lift time can be changed arbitrarily and continuously according to the driving state of the vehicle.

  By setting the lift timing of the intake valves 13F, 13R and the exhaust valves 15F, 15R as described above, for example, the volume efficiency is increased to improve the output, or the intake valve 13F is connected to the exhaust valves 15F, 15R. The amount of overlap of the valve opening timing of 13R is changed to optimize the internal EGR amount, thereby improving the fuel consumption and reducing the pumping loss, thereby reducing the fuel consumption. In addition, the intake air inflow time can be changed.

  That is, as shown in FIG. 6A, immediately after the opening of one intake valve 13F, the opposing exhaust valve 15F is closed and the intake opening 24 on the other intake valve 13R side is closed. Then, the state immediately before the exhaust opening 26 on the exhaust valve 15R side is closed (open state) is set. That is, an overlap is formed by one intake valve 13F and the other exhaust valve 15R.

  The air-fuel mixture inside the combustion chamber 22 forms a large swirl flow S1 from the side of one intake valve 13F in the left-turned state in the figure. Further, the exhaust return flow forms a swirl flow from the other exhaust valve 15R side in the left-turned state in the figure. Since the swirl flow S1 of the air-fuel mixture and the swirl flow returning from the exhaust gas are in the same direction, they grow into a larger swirl flow. Since the air-fuel mixture flows from the intake valve 13F on one side, the flow of the air-fuel mixture does not weaken due to interference on the exhaust valves 15F and 15R side. Further, there is no interference with the return of the exhaust.

  When the intake valves 13F and 13R and the exhaust valves 15F and 15R are opened and closed in the same phase, and the intake valve 13 and the exhaust valve 15 are overlapped, as shown in FIG. At the same time, the air-fuel mixture flows in from the 13F and 13R sides in opposite directions, and at the same time, the exhaust flows in from the exhaust valves 15F and 15R in the opposite directions. For this reason, the inflowing air-fuel mixture and the returned exhaust gas interfere with each other to cancel the flow, and the turbulence in the cylinder flow is attenuated. By setting the lift timing of the intake valves 13F, 13R and the exhaust valves 15F, 15R as described above, the flow of the mixture does not interfere with the returned exhaust gas and the flow is not canceled out.

  Returning to FIG. 6A, after that, the air-fuel mixture flows from the intake opening 24 on the other intake valve 13R side, but the large swirl flow S1 is maintained until the latter half of the compression stroke.

  As shown in FIG. 6B, the intake opening 24 on the other intake valve 13R side is open immediately before the closing of one intake valve 13F (timing to shift to the compression stroke). Blowback increases at the intake opening 24 on the other intake valve 13R side, and the inside of the combustion chamber 22 forms a large swirl flow S2 toward the other intake valve 13R side in the left-turned state in the figure. The swirl flow S2 having a large blowback from one side prevents the air-fuel mixture from interfering and weakening on the intake valves 13F and 13R side.

  As shown in FIG. 6C, when the intake opening 24 on the intake valve 13R side is closed with a delay and the piston reaches top dead center (immediately before ignition), the swirl flow S is strongly disturbed in the vicinity of the spark plug 60. To change. Thereby, the combustion reaction after ignition can be accelerated | stimulated.

  By setting the lift end timing of one intake valve 13F and the exhaust valve 15F earlier than the lift end timing of the other intake valve 13R and exhaust valve 15R, interference between intake air and interference between return of intake air and exhaust gas is prevented. Therefore, a large swirl flow can be formed inside the combustion chamber 22. As a result, a strong turbulence can be generated immediately before ignition, and combustion can be promoted to achieve low fuel consumption by improving combustion.

  For this reason, it is possible to optimally maintain the flow of intake air and the return of exhaust gas without impairing the characteristics of the variable valve mechanism.

  Further, by forming an overlap between one intake valve 13F and the other exhaust valve 15R, the internal EGR amount (exhaust gas return amount) is optimized without hindering swirl formation inside the combustion chamber 22, It is possible to improve fuel consumption and reduce pumping loss.

  Further, by arbitrarily operating the first cam phase changing means 51 and the second cam phase changing means 52, the lift timing of the intake valves 13F, 13R and the lift timing of the exhaust valves 15F, 15R are determined according to the vehicle operating state (engine rotation). Number, load, etc.) can be arbitrarily changed continuously. For this reason, output improvement and fuel consumption improvement can be aimed at.

  In the above-described embodiment, the example using the first worm 41, the first worm wheel 43, the second worm 40, and the second worm wheel 48 as the transmission means has been described. However, other means are used. Is possible. That is, as shown in FIG. 8, screw gears 101 and 102 are used instead of the first worm 41 and the first worm wheel 43, and screw gears 103 and 102 are used instead of the second worm 40 and the second worm wheel 48. 104 can be used.

  By using the screw gears 101 and 102 and the screw gears 103 and 104, the reduction ratio can be set to 1: 1. Further, it is possible to reduce the size of the rotation transmission mechanism between the first camshaft 1 and the first auxiliary camshaft 42 and the rotation transmission mechanism between the second camshaft 2 and the second auxiliary camshaft 47.

  The present invention can be used in the field of valve operating devices for internal combustion engines.

1 is an external view of a camshaft provided with a valve operating device according to an embodiment of the present invention. It is a principal part top view in FIG. It is the III-III arrow directional view in FIG. It is the IV-IV line arrow directional view in FIG. It is a time chart of valve operation. It is a conceptual diagram showing the flow condition in a cylinder (combustion chamber). It is a conceptual diagram showing the flow condition in a cylinder (combustion chamber). It is a principal part external view of the camshaft provided with the valve | bulb operation | movement apparatus which concerns on the other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st camshaft 2 2nd camshaft 11 1st lift means 12 2nd lift means 13 Intake valve 15 Exhaust valve 21 Cylinder head 22 Combustion chamber 42 1st auxiliary camshaft 45 1st intake cam 46 1st exhaust cam 47 1st 2 Auxiliary camshaft 49 Second intake cam 50 Second exhaust cam 101, 102, 103, 104 Screw gear

Claims (6)

A pair of intake valves and a pair of exhaust valves;
A first camshaft and a second camshaft that are rotated in synchronization with the drive rotation of the crankshaft;
First lift means for performing a lift operation in conjunction with one side intake valve and one side exhaust valve by rotation of the first camshaft;
Second lift means for performing a lift operation in conjunction with the other side intake valve and the other side exhaust valve by the rotation of the second camshaft ;
The first lift means includes
A first auxiliary camshaft to which the rotation of the first camshaft is transmitted, a first intake cam provided on the first auxiliary camshaft for lifting the one side intake valve, and provided on the first auxiliary camshaft. A first exhaust cam for lifting the one side exhaust valve;
The second lift means includes
A second auxiliary camshaft to which rotation of the second camshaft is transmitted; a second intake cam provided on the second auxiliary camshaft for lifting the other side intake valve; and provided on the second auxiliary camshaft. A valve operating device comprising a second exhaust cam for lifting the other side exhaust valve . The valve gear according to claim 1,
The first camshaft and the second camshaft are arranged in parallel with each other along one direction, and the first auxiliary camshaft and the second auxiliary camshaft intersect the first camshaft and the second camshaft. Arranged parallel to each other,
A valve operating system comprising transmission means for transmitting rotation of the first camshaft and the first auxiliary camshaft and transmitting rotation of the second camshaft and the second auxiliary camshaft, respectively. apparatus. The valve gear according to claim 2,
The valve operating device characterized in that the transmission means is a screw gear . The valve gear according to claim 3,
The valve operating device characterized in that the transmission means is a worm and a worm wheel . In the valve gear as described in any one of Claims 2-4,
The first lift means and the second lift means are:
A lash adjuster respectively provided corresponding to the pair of intake valves and the pair of exhaust valves;
A valve operating apparatus comprising: an arm that has one end as a fulcrum and is supported by the lash adjuster so as to be swingable, the other end abutting against the valve side, and an intermediate portion being pushed by a cam . The valve gear according to claim 5 ,
First cam phase changing means for arbitrarily changing the phase in the rotational direction of the first intake cam and the first exhaust cam;
And a second cam phase changing means for arbitrarily changing the phase of the second intake cam and the second exhaust cam in the rotational direction .

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