JP2009019531A - Engine lubrication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine lubrication device of dry sump lubrication system in which the bubble mix rate of the oil sucked into a feed pump is lowered. <P>SOLUTION: This engine lubrication device of dry sump lubrication system comprises an oil receiving part 155, a scavenging pump 170, and the feed pump 180 for supplying the oil into an engine. An oil return passage from the inside of the engine into an oil tank 165 is formed of a first passage extending through the scavenge pump 170 and a second passage extending through the oil return passage formed in a cylinder block 110. A gas-liquid separator 175 is disposed in the first passage on the downstream side of the scavenge pump 170. The outlet of the gas-liquid separator is connected to a pipe 176 opened near the suction hole of an oil strainer 181. An oil flow passage 200 is disposed at the lower side of the oil tank 165. The oil strainer 181 is disposed on the downstream side of the oil flow passage. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine lubrication device, and more particularly to an engine lubrication device employing a dry sump lubrication system.

  In general, a wet sump lubrication system and a dry sump lubrication system are known as engine lubrication systems.

  In the wet sump lubrication system, an oil pan that can store the total amount of lubricating oil supplied to the lubricated part and hydraulic operating part of the engine is installed at the bottom of the engine body, and the oil stored in this oil pan is oil pumped This is a method of supplying and lubricating to the lubricated part while sucking up. This wet sump lubrication system is used in many commercial vehicles because of its simple structure. However, in order to store the desired amount of lubricating oil, an oil pan having a predetermined depth is required, and the power generated by the engine crankshaft colliding with and stirring the lubricating oil surface stored in the oil pan. There are disadvantages such as loss and the fact that the lubrication of the oil surface in the oil pan caused by the acceleration / deceleration and turning of the vehicle causes the oil pump to lose lubrication due to poor suction. Yes.

  In response to these problems, the dry sump lubrication system has been developed especially for racing engines, etc. The dry sump lubrication system has an oil tank separately from the engine body and is provided at the bottom of the engine body. In this system, the oil in the oil pan (dry sump) is sucked up by a scavenge pump and stored in an oil tank, and the oil stored in the oil tank is supplied to a lubricated part by an oil feed pump and lubricated.

  As such a dry sump lubrication system, for example, a technique described in Patent Document 1 has been proposed. In the lubrication device for an internal combustion engine described in Patent Document 1, a pump housing portion is recessed in one corner of an oil pan that covers the lower surface of the crankcase of the engine in order to reduce the size of the dry sump lubrication device in the same manner as the wet sump type. At the same time, an oil tank portion having a relatively small volume whose upper surface is partitioned from the crankcase by a partition wall is formed on the lower surface side of the oil pan adjacent to the pump housing portion. A scavenge pump, a pressure pump (feed pump), and a gas-liquid separator are integrated in the pump housing portion, and a pump unit driven by a crankshaft is housed.

JP-A-4-246216

  By the way, the thing of patent document 1 sucks up all the lubricating oil (oil) which flowed down to the oil pan bottom face which covers the lower surface of the crankcase of an engine immediately with a scavenge pump, and an oil tank part passes through a gas-liquid separator. To be transferred to. Therefore, it is said that the number of bubbles contained in the oil transferred to the oil tank is very small.

  However, even when air bubbles are removed using a gas-liquid separator, the amount of oil discharged from the scavenge pump increases at the time of high engine rotation. The discharge speed is also increased, and there is a risk that bubbles will be re-entrained in the oil tank by the oil itself. In addition, the amount of oil that flows down to the bottom surface of the oil pan when the engine is running at a low speed is small, and the scavenge pump tends to suck up oil together with bubbles such as blow-by gas. In such a case, the particle size of the bubbles contained in the oil becomes large, and there is a possibility that the bubble removing action in the gas-liquid separator is not sufficiently performed. If oil containing such bubbles is supplied to the lubrication part of the engine or the hydraulic actuator by the feed pump, the lubrication part of the engine will be out of lubrication or the hydraulic actuator will malfunction, meaning that the dry sump lubrication system is adopted. I will not do it.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a dry sump lubrication system lubrication device that eliminates such conventional problems and can reduce the bubble mixing rate of oil sucked into the feed pump regardless of the engine rotation speed. There is to do.

  An embodiment of an engine lubrication apparatus according to the present invention that solves the above problems includes an oil receiving portion formed in a lower portion of the engine, a scavenge pump that transfers oil in the oil receiving portion to an oil tank, and a storage in the oil tank. A dry sump lubrication system lubrication device comprising a feed pump for supplying the oil into the engine, wherein an oil return path from the engine to the oil tank is a first path through the scavenge pump And a second path passing through an oil return passage formed in the cylinder block or the chain cover, and a first defoaming means is disposed downstream of the scavenge pump in the first path, An outlet from the first defoaming means opens near the suction port of an oil strainer disposed in the oil tank. Is connected to a pipe, the bottom surface of the oil tank with the second defoaming means is arranged, wherein the oil strainer downstream of defoaming means the second is arranged.

  Here, both the feed pump and the scavenge pump are preferably driven in synchronism with the engine speed.

  The first defoaming means is preferably a centrifugal gas-liquid separator.

  Furthermore, it is preferable that the second defoaming means is constituted by an oil flow path defined by a partition wall provided upright on the bottom surface of the oil tank.

  According to one aspect of the engine lubrication apparatus of the present invention, when oil stored in an oil tank is supplied into the engine by a feed pump, the supplied oil passes through the first path through the scavenge pump. And an oil return path constituted by a second path passing through an oil return path formed in the cylinder block or the chain cover. The oil returned to the oil tank through the first path is transferred to the oil tank by the scavenge pump from the oil receiving portion formed in the lower part of the engine, and the first defoaming means disposed downstream of the scavenge pump; The oil is discharged to the vicinity of the suction port of the oil strainer through a pipe connected to the outlet and opened near the suction port of the oil strainer arranged in the oil tank. Accordingly, since the oil separated from the scavenge pump through the first defoaming means is led to the vicinity of the suction port of the oil strainer by the pipe, it is sucked by the feed pump without causing re-entrainment of bubbles.

  On the other hand, the oil returned to the oil tank through the second path passes through the second defoaming means disposed on the bottom surface of the oil tank from the oil return passage formed in the cylinder block or the chain cover without passing through the scavenge pump. Then, it is led to an oil strainer arranged downstream thereof. The oil returned to the oil tank through the second path is guided to the oil strainer relatively slowly without being influenced by the discharge force of the scavenge pump, so that natural defoaming occurs between them and the oil with less bubbles mixed therein. Will be sucked into the feed pump. Therefore, the bubble mixing rate of oil sucked by the feed pump as a whole can be suppressed.

  Here, in the above aspect, according to an aspect in which both the feed pump and the scavenge pump are driven in synchronism with the engine speed, mixing of bubbles of oil sucked into the feed pump regardless of the rotational speed of the engine The rate can be reliably lowered.

  In addition to the above aspect, the first defoaming means is a centrifugal gas-liquid separator, and the second defoaming means is defined by a partition wall standing on the bottom surface of the oil tank. According to the configuration constituted by the oil flow path, the centrifugal gas-liquid separator efficiently defoams at the time of high rotation of the engine having a large discharge amount from the scavenge pump, and the separation efficiency at the time of low engine rotation. Therefore, natural defoaming can be performed by the oil flow path defined by the partition wall.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic longitudinal sectional view showing an embodiment in which an engine lubrication device according to the present invention is integrated, and FIG. 2 is a schematic transverse sectional view.

  The engine body 100 according to the present embodiment is configured such that a crankcase 120 is attached to a lower portion of a cylinder block 110 and a cylinder head 130 and a head cover 140 are sequentially coupled to the upper portion of the cylinder block 110. The crankcase 120 includes a front wall 121 and a rear wall 122 that are orthogonal to the crankshaft axis, and part of both side portions (front side) parallel to the crankshaft axis are the inner wall 123 and the outer wall 124 and both of them. And a space 125 that is open at the bottom.

  A flange 123f for attaching a first oil pan member as an oil receiving member, which will be described later, is formed at the lower end portion of the inner wall 123. Similarly, a flange for attaching an oil tank, which will be described later, is formed at the lower end portion of the outer wall 124. 124f is formed. In the present embodiment, on the rear side of the crankcase 120 to which a transmission or the like is attached, both lower ends of the inner walls 123 on both sides of the crankcase 120 are connected together with the rear wall 122 by the bottom wall 127 as an integral structure. The oil receiving portion is formed and the rigidity is ensured. The remaining part of the crankcase 120 excluding the bottom wall 127 forms an opening 129 surrounded by the first oil pan member mounting flange 123f.

  The first oil pan member 150 having a substantially flat bottom surface and a shallow bottom is attached to the lower surface of the flange 123f of the inner wall 123 of the crankcase 120 by a bolt (not shown) or the like via the flange 150f. A receiving portion 155 is formed. The first oil pan member 150, the front wall 121, the rear wall 122, the inner wall 123, and the bottom wall 127 define the inside of a crankcase that houses a rotating body such as the crankshaft 112 and the pair of balance shafts 114. Yes.

  The piston 116 is accommodated in the bore in the cylinder block 110 so as to be able to reciprocate. The connecting rod 118 converts the reciprocating motion of the piston 116 into the rotational motion of the crankshaft 112. In addition, a combustion chamber is formed in the cylinder head 130 and is connected to an intake port and an exhaust port (not shown) of the combustion chamber, respectively, and an intake manifold and an exhaust manifold (both not shown) are connected. The intake port and the exhaust port are opened and closed by an intake valve and an exhaust valve, respectively, and these intake / exhaust valves are driven by an intake / exhaust camshaft (not shown). In the present embodiment, as will be described later, a variable intake valve timing mechanism VVT-i for changing the operation timing of the intake valve is provided, and the operation oil supplied to the variable intake valve timing mechanism VVT-i is switched. An oil control valve OCV is also disposed in the cylinder head 130 and the head cover 140. Reference numeral 119 denotes an oil return passage formed in the cylinder block 110 for returning a part of the oil supplied to the cylinder head 130 to an oil tank 165 described later. Further, a timing chain is wound between a sprocket 117 provided at the extreme end of the crankshaft 112 and a sprocket (not shown) provided on each of the intake / exhaust camshafts described above, and covers these. The chain cover 111 is attached to the cylinder block 110.

  Furthermore, in the engine main body 100 according to the present embodiment, the second oil pan member 160 is also bolted to the lower surface of the flange 124f of the outer wall 124 of the crankcase 120 and the flange 111f of the chain cover 111 via the flange 160f. It is attached with. The second oil pan member 160 is attached in such a manner that it is deeper than the shallow first oil pan member 150 and covers from below while having a predetermined distance including the entire surface. Thus, the oil tank 165 is configured together with the space 125 of the crankcase 120 described above. The oil tank 165 includes a second oil pan member 160 having a substantially flat bottom surface, a space between the flat bottom surface and the lower surface of the first oil pan member 150, a front wall 121 of the crankcase 120, The space between the chain cover 111 and the space 125 between the inner wall 123 and the outer wall 124 on both sides of the crankcase 120 is included as an internal volume, and the axis of the crankshaft 112 of the engine body 100 is included. It is substantially symmetrical with respect to the center plane. In the oil tank 165, the internal volume is determined such that the oil surface OL when the engine is stopped is above the lower surface of the mounting flange 123f of the first oil pan member 150.

  In the present embodiment, a scavenge pump 170 that transfers oil collected in the main oil receiving portion 155 to the oil tank 165 is provided inside the crankcase so as to be driven by one of the pair of balance shafts 114. ing. The feed pump 180 that supplies the oil stored in the oil tank 165 into the engine body 100 is also disposed inside the crankcase so as to be driven by the other of the pair of balance shafts 114.

  The driven gear 113 provided on one of the pair of balance shafts 114 is driven by the drive gear 115 press-fitted into the counterweight of the crankshaft 112. As is well known, the pair of balance shafts are rotated in opposite directions in synchronization with each other by a driven gear (not shown) that meshes with each other.

  The suction port of the scavenge pump 170 is connected to an oil strainer 171 opened close to the upper surface of the first oil pan member 150 forming the main oil receiving portion 155 via the suction pipe 172, and the scavenge pump The discharge port 170 is connected to the first discharge pipe 174. Further, the first discharge pipe 174 is connected to the inlet of a centrifugal gas-liquid separator 175 as a first defoaming means, and an oil strainer disposed in the oil tank 165 is connected to the outlet of the gas-liquid separator 175. A second discharge pipe 176 serving as a later-described pipe that opens near the suction port 181 is connected.

  The suction port of the feed pump 180 is connected to the above-described oil strainer 181 opened close to the second oil pan member 160 constituting the oil tank 165 via the suction pipe 182. Further, the discharge port of the feed pump 180 is connected to a supply passage for lubrication or hydraulic oil formed in the crankcase 120 or the cylinder block 110, and to a discharge pipe (not shown) communicating with an oil filter (not shown) in this figure. ing. Reference numeral 190 denotes a bottom surface of the oil tank 165, in other words, a partition wall provided upright on the second oil pan member 160, which defines the oil flow path 200 as will be described later.

  Therefore, a second discharge pipe 176 connected to the oil flow path 200 defined by the partition wall 190 and the outlet of the gas-liquid separator 175 and opened near the suction port of the oil strainer 181 and the oil strainer 181 of the feed pump 180 are provided. A configuration relating to the arrangement of the suction ports will be described with reference to FIGS. 3 and 4.

  FIG. 3 is a perspective view of the second oil pan member 160 in a state where the second oil pan member 160 constituting the lower portion of the oil tank 165 is removed from the crankcase 120 and the chain cover 111. FIG. 4 is a bottom view of the crankcase 120 in a state where only the second oil pan member 160 is removed with the first oil pan member 150 attached.

  In this embodiment, the four corners of the oil tank 165 whose basic shape is substantially rectangular in plan view are curved inward, and a recess 166 for attaching the oil filter 195 is formed evenly. The partition wall 190 includes a first partition wall 190A disposed substantially parallel to the central surface including the axis of the crankshaft 112, a second partition wall 190B and a second partition wall 190B intersecting at substantially right angles with both ends thereof. The first partition wall 190C and the third partition wall 190C have bent portions 190Ba and 190Ca that are bent inward, respectively, and have a substantially C shape in plan view. Has been. The free end portions of the second partition wall 190B and the third partition wall 190C are disposed leaving a gap between the above-described recessed portion 166 and the inner wall of the even-numbered curved portion, respectively. An inlet 204 to the storage chamber 202 in which the oil strainer 181 of the feed pump 180 is disposed is formed between the bent portions 190Ba and 190Ca of the second partition wall 190B and the third partition wall 190C. A second discharge pipe 176 is connected to the first partition wall 190 </ b> A, and an outlet thereof is opened near the suction port of the oil strainer 181.

  Note that the upper ends of the three first partition walls 190 </ b> A to 190 </ b> C are in contact with the lower surface of the first oil pan member 150 when the second oil pan member 160 is attached to the crankcase 120. Thus, the oil flow path 200 is formed with the solid arrow in FIG. 3 as the main stream line and the above-described storage chamber 202 as the downstream end.

  Next, the oil circulation system in the present embodiment will be described with reference to FIG. In the present embodiment, first, oil sucked from the oil tank 165 by the feed pump 180 via the oil strainer 181 is pressure-fed to the main oil hole 210 formed in the cylinder block 110 via the oil filter 195. A supply passage is formed in the crankcase 120 as much as possible. As a first supply system, oil is sent from the main oil hole 210 to the cylinder head 130 via a supply passage formed in the cylinder block 110, and the intake / exhaust camshaft journal 220 and the variable intake valve timing mechanism VVT. -I oil control valve OCV230. At the same time, the oil is sent from the main oil hole 210 through the cylinder head 130 to the chain tensioner 240 and at the same time to the oil jet 250 formed in the cylinder block 110 and supplied to the timing chain 117.

  On the other hand, as a second supply system, the oil is sent from the main oil hole 210 to the journal 260 of the crankshaft 112 in the cylinder block 110, and to the crankpin 270 which is a connecting portion with the connecting rod 118 via the journal. Supplied. At the same time, it is sent to the oil jet 280 through the journal 260 of the crankshaft 112 and is supplied to the lower surface of the piston 116 by injection. After the oil sent to the second supply system is used for lubrication of the respective supply points, the oil naturally falls on the bottom wall 127 and the main oil receiving portion 155 at the lower part of the crankcase 120, and finally Is recovered by the main oil receiving portion 155 formed of the first oil pan member 150.

  On the other hand, the oil returned to the oil tank 165 of the oil pumped by the feed pump 180 in this way is collected in the main oil receiving portion 155 as described above, and is pumped up from there by the scavenge pump 170 and the air. A first return path for returning to the oil tank 165 via the liquid separator 175, and a second return path for returning the oil supplied to the cylinder block 110 or the cylinder head 130 of the engine body 100 directly to the oil tank 165. have. The second return path will be described in more detail. In the present embodiment, an oil return passage 300 formed in the chain cover 111 through which the oil supplied to the chain tensioner 240 and the timing chain 117 circulates is described. One of them is configured. The other of the second return paths is an oil return passage 119 formed in the cylinder block 110 for returning the oil from the cylinder head 130 by natural fall, and a crankcase 120 for communicating with the oil return passage 119. The communication path 128 is formed in the upper portion so as to open to the space 125.

  Here, the operation of the present embodiment configured as described above will be described. During the operation of the engine 100, the oil in the oil tank 165 is sucked up through the oil strainer 181 by the feed pump 180 driven in synchronization with the engine speed by the crankshaft 112, and the oil filter 195 and the main oil hole Via 210, the crankcase 120 or the cylinder block 110 is supplied to a supply passage. The oil supplied to the lubricated part or the hydraulic operation part is connected to the first path through the scavenge pump 170, the oil return path 119 formed in the cylinder block 110, and the communication path 128 formed in the crankcase 120. Alternatively, the oil is returned to the oil tank 165 through an oil return path formed by a second path that passes through the oil return path 300 formed in the chain cover 111. The oil returned to the oil tank 165 through the first path is transferred to the oil tank 165 by the scavenge pump 170 from the oil receiving portion 155 formed in the lower part of the engine. The liquid is discharged through the liquid separator 175 and the second discharge pipe 176 to the storage chamber 202 in which the oil strainer 181 is disposed. Therefore, the oil defoamed from the scavenge pump 170 through the gas-liquid separator 175 is guided to the vicinity of the suction port of the oil strainer 181 by the second discharge pipe 176, and therefore, the feed pump 180 is not re-entrained. Will be sucked.

  On the other hand, the oil returned to the oil tank 165 through the second path does not pass through the scavenge pump 170, the oil return path 119 formed in the cylinder block 110 and the communication path 128 formed in the crankcase 120, or The oil naturally falls from the oil return passage 300 formed in the chain cover 111 to the oil tank 165. Then, it flows through the oil flow path 200, reaches the storage chamber 202 through the inlet 204, and is guided to the oil strainer 181 disposed there. The oil that is returned to the oil tank 165 through this second path is guided to the oil strainer 181 relatively slowly without being influenced by the discharge momentum of the scavenge pump 170. Oil with less contamination is sucked into the feed pump 180. Therefore, the bubble mixing rate of oil sucked by the feed pump 180 as a whole can be suppressed.

  Thus, the degassing is efficiently performed by the centrifugal gas-liquid separator 175 when the engine 100 having a large discharge amount from the scavenge pump 170 is rotated at a high speed, and the centrifugal efficiency is decreased when the engine 100 is rotated at a low speed. By reducing the dependence on the liquid separator 175 and performing natural defoaming by the oil flow path 200 defined by the partition wall 190, the oil sucked into the feed pump 180 regardless of the rotational speed of the engine 100 is obtained. The bubble mixing rate can be reliably lowered.

  In this embodiment, the first return path and the second return path described above are used for the purpose of reducing the bubble mixing rate of the oil sucked into the feed pump 180 over the entire rotation region of the engine 100 as described above. The flow rate ratio of the oil returned to the oil tank 165 is set to be about 7 to 3. That is, the flow resistance of the first supply system sent from the main oil hole 210 to the cylinder head 130 and the oil jet 250 and the flow resistance of the second supply system in the cylinder block 110 are set. The discharge capacities of the feed pump 180 and the scavenge pump 170 are set. Specifically, the oil supplied to the first supply system is returned to the oil tank 165 by natural fall through the second return path as described above, and the oil supplied to the second supply system is the crankcase. 120 naturally falls on the bottom wall 127 of the lower part of 120 and the main oil receiving part 155 and is collected in the main oil receiving part 155, and finally returned to the oil tank 165 by the scavenge pump 170 via the first return path. The discharge capacity of the scavenge pump 170 is about 70% of the discharge capacity of the feed pump 180. In other words, the rated discharge capacity ratio between the scavenge pump 170 and the feed pump 180 is about 0.7. According to this embodiment, the power for driving the scavenge pump 170 can be reduced as compared with the conventional dry sump system in which the total amount of oil supplied into the engine is returned to the oil tank 165 by the scavenge pump 170. 100 fuel efficiency can be improved.

  Here, in the present embodiment, the second return path is formed in the chain cover 111 so as to open to the space 125 in the oil return passage 300 and / or the crankcase 120 formed from the cylinder head. A communication path 128 is formed in the cylinder block 110 and communicates with the oil return path 119 from the cylinder head 130. As a result, oil can be returned directly to the oil tank 165 by using gravity without using the scavenge pump 170, and the power loss for driving the scavenge pump 170 can be effectively reduced. . Therefore, the power for driving the scavenge pump 170 in the low-speed rotation region of the engine having a relatively small oil stirring resistance while enjoying the advantages of the dry sump lubrication method in the high-speed rotation region of the engine in which the power loss due to the oil stirring resistance is larger. The fuel consumption performance of the engine can be improved by reducing the loss. Furthermore, the discharge capacity of the scavenge pump 170 may be smaller than the discharge capacity of the feed pump 180, which is advantageous in terms of cost.

It is a longitudinal cross-sectional schematic diagram which shows embodiment in which the engine lubricating device which concerns on this invention was integrated. 1 is a schematic cross-sectional view showing an embodiment in which a lubricating device for an engine according to the present invention is integrated. In the embodiment of the engine lubrication device according to the present invention, it is a perspective view showing a state before the second oil pan member constituting the lower portion of the oil tank is attached. FIG. 5 is a bottom view of the crankcase in a state in which only the second oil pan member is removed with the first oil pan member attached in the embodiment of the engine lubrication apparatus according to the present invention. It is a block diagram which shows the circulation system of the oil in embodiment of the lubricating apparatus of the engine which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Engine main body 110 Cylinder block 111 Chain cover 112 Crankshaft 113 Driven gear 114 Balance shaft 115 Drive gear 116 Piston 118 Connecting rod 119 Oil return path 120 Crankcase 121 Front wall 122 Rear wall 123 Inner side wall 124 Outer side wall 125 Space part 127 Bottom wall 129 Opening portion 130 Cylinder head 140 Head cover 150 First oil pan member 155 Main oil receiving portion 160 Second oil pan member 165 Oil tank 170 Scavenge pump 171 Oil strainer 174 First discharge pipe 175 Gas-liquid separator 176 Second discharge Pipe 180 Feed pump 181 Oil strainer 190 Partition wall 200 Oil flow path

Claims (4)

A dry sump lubrication system comprising an oil receiving portion formed at a lower portion of an engine, a scavenge pump for transferring oil in the oil receiving portion to an oil tank, and a feed pump for supplying oil stored in the oil tank into the engine. An engine lubrication device,
An oil return path from the engine to the oil tank is composed of a first path passing through the scavenge pump and a second path passing through an oil return path formed in the cylinder block or chain cover,
A first defoaming means is disposed downstream of the scavenge pump in the first path, and an outlet from the first defoaming means is in the vicinity of a suction port of an oil strainer disposed in the oil tank. Connected to the pipe that opens to
An engine lubrication device, wherein a second defoaming means is disposed on the bottom surface of the oil tank, and the oil strainer is disposed downstream of the second defoaming means.   The engine lubrication device according to claim 1, wherein both the feed pump and the scavenge pump are driven in synchronization with an engine speed.   3. The engine lubrication device according to claim 1, wherein the first defoaming means is a centrifugal gas-liquid separator.   The said 2nd degassing means is comprised by the oil flow path defined by the partition wall standingly arranged by the bottom face of the said oil tank, The Claim 1 thru | or 3 characterized by the above-mentioned. Engine lubrication device.

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