JP2011127552A - Common rail type fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a common rail type fuel injection device including a common rail storing fuel pressurized by a high-pressure pump, an injector injecting the fuel stored in the common rail, and a control device controlling operation of the high-pressure pump and the injector, and reducing an amount of foreign matter such as metal pieces and a metal powder entering the injector. <P>SOLUTION: The common rail type fuel injection device includes the common rail storing the high-pressure fuel pressurized by the high-pressure pump, the injector injecting the fuel stored in the common rail into the combustion chamber of an engine, and the control device controlling the operation of the high-pressure pump and the injector. The common rail type fuel injection device includes a magnet body for attracting the foreign matter by magnetic force in the common rail or in a flow passage from the common rail to the injector and at a position where the high-pressure fuel stagnates. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a common rail that stores high-pressure fuel pressurized by a high-pressure pump, an injector that injects fuel stored in the common rail into a combustion chamber of an engine, and a control device that controls operations of the high-pressure pump and the injector. In particular, the present invention relates to a common rail fuel injection device capable of reducing the amount of foreign matter such as metal pieces and metal powder entering the injector.

  A common rail fuel injection device is known as one of fuel injection devices for diesel engines. A common rail type fuel injection device stores high pressure fuel in a container called a common rail, and supplies the high pressure fuel from the common rail to an injector provided for each cylinder of the engine.

  In a common rail type fuel injection device, fuel stored in a fuel tank is pressurized by a high pressure pump, the pressurized fuel is sent to a common rail and stored in a high pressure state, and an engine control unit (Engine Control Unit: hereinafter referred to as ECU). When the nozzle of the injector that needs to inject fuel is opened and closed according to an instruction from, the fuel stored in the common rail is injected from the injector.

  By using a common rail fuel injection system, the injection pressure and injection timing, which are important elements of fuel injection, are independently controlled without depending on the engine speed, and the fuel injection amount and injection rate can be set arbitrarily. It is possible to adjust, and multiple injections in one combustion cycle are also possible. Furthermore, it is possible to atomize the fuel by injecting at a high pressure and improve the mixing property of the fuel and air.

  However, when using the common rail type fuel injection device, there is a possibility that metal pieces or metal powder generated due to peeling or wear of parts on the sliding surface of the high pressure pump or the like flows into the injector together with the fuel. When the metal piece or metal powder flows into the injector, the injector may be clogged, or the sliding surface of the injector may be abnormally worn or fixed.

  Therefore, when using a common rail type fuel injection device, it is important to thoroughly manage the cleanliness of each component part during production, and even if the metal piece or metal powder is generated during operation, the metal piece or It is necessary to take measures to prevent metal powder from flowing into the injector.

  Therefore, Patent Document 1 discloses a fuel filter having a magnetic body that adsorbs foreign matter by magnetic force in a filter that removes foreign matter contained in fuel flowing into an injector that injects and supplies fuel. Yes.

JP 2006-336594 A

  However, in the technique disclosed in Patent Document 1, although the metal pieces and metal powder collected by the filter and the metal pieces and metal powder staying in the vicinity of the filter can be adsorbed and collected by the magnetic body, the fuel At the same time, it is difficult to adsorb and collect the metal pieces and metal powder that flow together with the magnetic material. Therefore, there is a possibility that a metal piece or metal powder may enter the injector. In particular, the fine metal powder that cannot be collected by the filter is likely to enter the injector together with the fuel.

  Therefore, in view of the problems of the prior art, the present invention controls a common rail that stores fuel pressurized by a high-pressure pump, an injector that injects fuel stored in the common rail, and operations of the high-pressure pump and the injector. It is an object of the present invention to provide a common rail fuel injection device that can reduce the amount of foreign matter such as metal pieces and metal powder entering the injector.

  In order to solve the above problems, in the present invention, a common rail that stores high-pressure fuel pressurized by a high-pressure pump, an injector that injects fuel stored in the common rail into a combustion chamber of an engine, and the high-pressure pump and the injector And a control device for controlling operation, wherein the magnet adsorbs foreign matter by magnetic force at the position where the high-pressure fuel stays in the common rail or in the flow path from the common rail to the injector. It has a body.

As a result, at the position where the fuel stays, the fuel becomes stagnation, and foreign matters such as metal pieces and metal powder float in the stagnation fuel. Therefore, by having a magnet body that adsorbs foreign matter by the magnetic force at a position where the fuel stays, foreign matters floating in the fuel can be easily adsorbed and collected.
In addition, a magnet body can also be attached by affixing on the said common rail etc., and a part of common rail or the said flow path can also be comprised with a magnet body.

It is good to have the said magnet body in the component which can be removed from the said common rail.
Thereby, when the amount of foreign matter attracted and collected by the magnet body increases, the magnet body can be removed and cleaned or replaced. Therefore, it is possible to prevent the foreign matter collecting efficiency from being reduced due to an increase in the amount of foreign matter accumulated in the magnet body by adsorption and collection, and the foreign matter once collected from being separated from the magnet body. Furthermore, since the collected foreign matter can be removed simply by removing the magnet body and cleaning or exchanging the collected foreign matter, the collected foreign matter can be easily removed and maintenance can be improved.

Moreover, it is good to attach the said magnet body to the plug provided in the longitudinal direction edge part of the said common rail, or to form this plug with a magnet body.
The plug is also generally present in conventional common rail fuel injection devices, and without attaching the magnet body or using the plug as a magnet body, without increasing the number of parts that can be removed from the common rail. Implementation of the present invention becomes possible.

  In addition, a pipe connecting the common rail and the injector has a casing, a fuel outlet formed in the casing, and a hollow portion, and receives the pressure of the fuel flowing into the hollow portion from the common rail. A valve body that slides on the valve body, a valve seat that is formed in the casing and has a shape on which the valve body can be seated, and an elastic body that is disposed in the casing and presses the valve body away from the valve seat. A flow limiter having a communication hole that communicates the hollow portion provided in the valve body and the outflow port may be provided, and at least a part of the flow limiter may be formed of a magnet body.

  By forming at least a part of the flow limiter with a magnet body, foreign matters such as metal pieces and metal powder can be adsorbed and collected with high efficiency by the flow limiter. Thereby, since a foreign material can be collected with the flow limiter provided in piping which connects a common rail and an injector, the amount of foreign material which penetrates into the inside of an injector can be reduced significantly.

Furthermore, since the flow limiter is a part that can be removed from the common rail and replaced, when the amount of foreign matter such as metal pieces or metal powder collected and collected near the communication hole increases, the valve element or flow limiter Entire cleaning or replacement is possible.
Furthermore, as the number of foreign matter collected by the magnet body increases, the flow rate of the communication hole is narrowed by the foreign matter, and the injection performance from the injector is reduced. That is, it is possible to estimate the amount of foreign matter collected in the magnet body due to the decrease in the injection performance, and it is possible to determine the appropriate cleaning or replacement timing of the valve body or the flow limiter.

Moreover, it is good to form the part which comprises the communicating hole of the said valve body with a magnet body.
As a result, since foreign matter is collected in the vicinity of the communication hole, there is a correlation between the amount of foreign matter collected by the magnet body and a decrease in injection performance due to the communication hole becoming narrow due to the foreign matter. Get higher. Therefore, it is possible to determine a more appropriate cleaning or replacement timing of the valve body or the flow limiter.

Further, a differential pressure gauge for measuring a differential pressure between the pressure of the high pressure fuel stored in the common rail and the pressure of the high pressure fuel supplied to the injector may be provided.
If the amount of foreign matter collected by the magnet body increases, the presence of the foreign matter is expected to reduce the flow passage area of the flow passage of the high-pressure fuel from the common rail to the injector, thereby reducing the fuel injection performance from the injector. By measuring the differential pressure of the high-pressure fuel before and after passing through the flow path with the differential pressure gauge, it is possible to estimate the amount of foreign matter collected and accumulated in the magnet body that causes the deterioration of the injection performance. . Accordingly, by providing the differential pressure gauge and estimating the amount of foreign matter collected and accumulated in the magnet body, it is possible to determine the appropriate cleaning or replacement timing of the magnet body such as a valve body or a flow limiter.

  As described above, according to the present invention, the common rail that stores the fuel pressurized by the high-pressure pump, the injector that injects the fuel stored in the common rail, and the control device that controls the operations of the high-pressure pump and the injector are provided. In the provided common rail fuel injection device, the amount of foreign matter such as metal pieces and metal powder entering the injector can be reduced.

1 is an overall configuration diagram of a common rail fuel injection device in Embodiment 1. FIG. It is one top view of the block which comprises the common rail in Example 1, Comprising: One part is shown with the cross section. FIG. 3 is a front view in the direction A in FIG. It is one front view of the block which comprises the common rail in Example 2, Comprising: One part is shown with the cross section. 6 is a cross-sectional view of a flow limiter in Embodiment 3. FIG. It is the B section enlarged view in FIG.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

First, the overall configuration of the common rail fuel injection device according to the first embodiment will be described with reference to FIGS. 1, 2, and 3.
FIG. 1 is an overall configuration diagram of a common rail fuel injection device according to a first embodiment.

  As shown in FIG. 1, the common rail type fuel injection device according to the first embodiment includes a fuel tank 12, a high pressure pump 10, a common rail 2, a flow limiter 4, an injector 6, an ECU 18, and the like.

  The suction side of the high-pressure pump 10 is connected to a fuel tank 12 by a low-pressure fuel pipe 11, and the low-pressure fuel pipe 11 is provided with a feed pump 14 and a filter 16 in order from the fuel tank 12 side.

  On the other hand, the discharge side of the high-pressure pump 10 is connected to the common rail 2. As shown in FIG. 1, the common rail 2 includes three blocks 2a, 2b, and 2c, and the discharge side of the high-pressure pump 10 is connected to the block 2a. Further, the block 2a and the block 2b are connected by a pipe 23b, and the block 2a and the block 2c are connected by a pipe 23c so that fluid (fuel) can freely flow between the blocks 2a, 2b, and 2c. In this embodiment, the common rail 2 is composed of three blocks 2a, 2b, and 2c, but can store fuel pressurized by the high-pressure pump 10 as will be described later. If it exists, it may be composed of one, two, or four or more blocks.

  One or a plurality of (six in FIG. 1) injectors 6 corresponding to engine cylinders (not shown) are connected to the common rail 2 by high-pressure fuel pipes 8. The first embodiment shows an example in which the engine has six cylinders and six injectors 6 are provided corresponding to the cylinders of the engine.

  In addition, a flow limiter 4 is provided in each of the high-pressure fuel pipes 8 connecting the common rail 2 and the injector 6. The flow limiter 4 shuts off the high-pressure fuel pipe 8 when the fuel leaks from the high-pressure fuel pipe 8 connecting the common rail 2 and the injector 6 or excessive fuel injection occurs from the injector 6. It is provided to stop the supply of fuel.

  An ECU 18 for controlling operations of the injector 6 and the high-pressure pump 10 is provided. The ECU 18 determines the fuel injection amount, the injection timing, and the like from the injector 6 based on output information such as the engine speed, the accelerator opening, the pressure in the common rail 2 and the like detected by a sensor (not shown). And feedback control of the operation of the high-pressure pump 10.

FIG. 2 is a plan view of one of the blocks (2c) constituting the common rail 2 in the first embodiment, and a part thereof is shown in cross section. FIG. 3 is a front view in the direction A in FIG. 2, and a part thereof is shown in cross section.
2 and 3, reference numeral 21 denotes a fuel inlet to the block 2c of the common rail 2, which corresponds to a connection portion between the block 2a shown in FIG. 1 and the block 2c of the pipe 23c connecting the block 2c. Reference numeral 22 denotes a pressure sensor for detecting the pressure in the block 2c, that is, in the common rail 2.

  The block 2 c constituting the common rail 2 has a substantially cylindrical storage space 25 formed therein, and the high-pressure fuel pumped by the high-pressure pump 10 is stored in the storage space 25.

  Further, a plug 23 is provided at an end portion in the longitudinal direction of the storage space 25, and there is no fuel circulation in the storage space 25 other than the high-pressure fuel pipe 8 connected via the fuel inlet 21 and the flow limiter 4. It is configured as follows. The plug 23 is removable when the operation of the entire common rail fuel injection device is stopped.

  Further, as a characteristic configuration of the present invention, a magnet 24 a is attached to the entire inner peripheral wall of the storage space 25 and attached.

  2 and 3, only the block 2c that constitutes the common rail 2 has been described, but the blocks 2a and 2b that constitute the common rail 2 also have a substantially cylindrical shape that stores the high-pressure fuel therein, as in the block 2c. A storage space is formed, and a magnet is attached to the entire inner peripheral wall of the storage space.

  Next, the operation of the common rail fuel injection device according to the first embodiment will be described with reference to FIGS. 1, 2, and 3.

  The fuel stored in the fuel tank 12 is sucked by the feed pump 14. The fuel sucked by the feed pump 14 is sent to the high pressure pump 10 via the low pressure fuel pipe 11. The fuel sent to the high-pressure pump 10 is compressed by the high-pressure pump 10 to be increased in pressure, and is sent into the common rail 2 by pressure.

The fuel pumped into the common rail 2 is stored in the common rail 2 in a high pressure state.
The high pressure fuel stored in the common rail 2 is distributed to the plurality of injectors 6 through the flow limiter 4 and the high pressure fuel pipe 8 under the control of the ECU 18. The injector 6 injects the high-pressure fuel into an engine combustion chamber (not shown) at a timing controlled by the ECU 18.
With the above operation, the high-pressure fuel independently controls the injection pressure, the fuel injection amount, the injection timing, the injection rate, etc., which are important elements of the fuel injection, without depending on the engine speed, under the control of the ECU 18. It becomes possible.

  Here, the high-pressure fuel stored in the common rail 2 includes metal pieces and metal powder generated due to peeling and wear of parts at the sliding portion of the high-pressure pump 10, and metal pieces generated due to rust in the fuel tank 12. Or metal powder may be mixed.

  The high-pressure fuel in which the metal pieces and metal powder are mixed is stored in the common rail 2 until it is distributed to the injector 6 under the control of the ECU 18 and injected into the combustion chamber of the engine as described above. At the time of the storage, the metal pieces and the metal powder are floating in the stored high-pressure fuel.

Metal pieces and metal powder that float in the high-pressure fuel stored in the common rail 2 are attached to the magnet attached to the entire inner peripheral wall of the storage space in each block 2a, 2b, 2c of the common rail 2. It is attracted and collected by adsorption. In particular, in the present invention, since the magnet is provided in the storage space 25 of the common rail 2 in which high-pressure fuel stays, the collection efficiency of the metal pieces and metal powder by the magnet is high.
As a result, the amount of foreign matter that passes through the high-pressure fuel pipe 8 and enters the injector 6 can be greatly reduced.

  The overall configuration of the common rail fuel injection device according to the second embodiment is the same as that of the common rail fuel injection device described with reference to FIG. 1 in the first embodiment. It will be used as a configuration diagram and its description will be omitted.

  FIG. 4 is a front view of one of the blocks (2c) constituting the common rail 2 in the second embodiment, and a part thereof is shown in cross section. In FIG. 4, the same reference numerals as those in FIGS. 1 to 3 represent the same items, and the description thereof is omitted.

In FIG. 4, instead of the magnet 24a shown in FIG. 3, a magnet 24b is attached and attached to the entire surface of the plug 23 facing the storage space 25.
Since the plug 23 is provided at the longitudinal end of the storage space 25, the magnet 24 b is provided at the longitudinal end of the storage space 25.

  In FIG. 4, only the block 2 c constituting the common rail 2 has been described, but the blocks 2 a and 2 b constituting the common rail 2 are also plugs provided at the longitudinal ends of the storage space 25 in the same manner as the block 2 c. A magnet is attached to the entire surface facing the storage space 25.

By providing the magnet 24b, the metal pieces and metal powder that float in the high-pressure fuel stored in the common rail 2 are provided in the longitudinal ends of the storage spaces of the blocks 2a, 2b, and 2c of the common rail 2. It is attracted and collected by the magnet 24b attached to the plug. In particular, since the magnet 24b is located in the storage space 25 of the common rail 2 where high-pressure fuel stays, recovery efficiency of the metal pieces and metal powder by the magnet is high.
Thereby, the amount of foreign matter that passes through the high-pressure fuel pipe 8 and enters the injector 6 can be greatly reduced.

  Further, a magnet 24b is attached by being attached to a plug 23 that is removable from the common rail 2. Therefore, it is possible to remove the plug 23 from the magnet 24b and remove foreign matter such as metal pieces and metal powder that have been attracted and collected by the magnet 24b. When the amount of foreign matter such as metal pieces and metal powder collected by the magnet 24b increases, the metal accumulated in the magnet 24b is removed by removing the plug 23 and removing the metal pieces and metal powder accumulated in the magnet 24b. It is possible to prevent a piece or metal powder from leaving the magnet 24 b and passing through the high-pressure fuel pipe 8 and entering the injector 6. Furthermore, since the foreign matter collected by cleaning or exchanging the magnet 24b can be removed simply by removing the plug 23, the collected foreign matter can be easily removed.

  In the second embodiment, the magnet 24b is attached and attached to the plug 23. However, the same effect can be obtained even if the plug 23 itself is formed of a magnet body.

FIG. 5 is a cross-sectional view of the flow limiter 4 in the third embodiment.
As shown in FIG. 5, the flow limiter 4 is formed in a casing 41, an outlet 42 that is formed in the casing 41 and guides fuel inside the flow limiter to the high-pressure fuel pipe 8, and is stored in the casing 41 and flows into the hollow portion 47 from the common rail 2. The valve body 43 is slid by receiving the pressure of the fuel, the valve seat 44 is formed in the casing 41 and has a shape on which the valve body 43 can be seated, and the valve body 43 disposed in the casing 41 is moved away from the valve seat 44 It comprises a spring 45 that presses against.

  The valve body 43 is formed in a shape that can be fitted to the valve seat 44 at the tip. In addition, a communication hole 46 that allows the hollow portion 47 and the space outside the valve body 43 to communicate with each other is formed in a portion of the valve body 43 that is closer to the tip of the hollow portion 47.

  In the flow limiter 4, when high-pressure fuel from the common rail 2 flows into the hollow portion 47, the high-pressure fuel moves the valve body 43 toward the valve seat 44 against the pressing force of the spring 45, and communicates from the hollow portion 47. It flows into the injector 6 through the hole 46 and the outlet 42 and the high-pressure fuel pipe 8.

In the flow limiter 4, the valve body 43 is in contact with the seat portion 48 as shown in FIG. 5 when the fuel supplied from the common rail 2 is not supplied or is extremely small.
Further, when the pressure of the fuel supplied from the common rail 2 becomes a predetermined value or more, the tip of the valve body 43 is fitted and seated on the valve seat 44, and the fuel supply to the injector 6 is stopped. ing.

  In the flow limiter 4 configured as described above, the valve body 43 is formed of a magnet body as a characteristic configuration of the present invention.

  FIG. 6 is an enlarged view of a portion B in FIG. As shown in FIG. 6, by forming the valve body 43 with a magnet body, the foreign matter 100 such as the metal piece or metal powder can be adsorbed and collected in the vicinity of the communication hole 46 with high efficiency. The amount of foreign matter that passes through 8 and enters the inside of the injector 6 can be greatly reduced.

  Further, the flow limiter 4 is a component that can be removed from the common rail 2 and replaced. Therefore, when the amount of foreign matter 100 such as metal pieces or metal powder collected and collected near the communication hole 46 is increased and the fuel flow is obstructed to deteriorate the injection performance, the common rail 2 to the flow limiter 4 Replacing can restore the injection performance. Moreover, it is possible to prevent the foreign matter 100 once collected from passing through the high-pressure fuel pipe 8 and entering the injector 6 together with the flow of the high-pressure fuel. Further, since the collected foreign matter can be removed simply by exchanging the flow limiter 4, it is easy to remove the collected foreign matter.

  Further, as the number of foreign matter collected near the communication hole 46 as shown in FIG. 6 increases, the flow path of the communication hole 46 is narrowed by the foreign matter, and the injection performance from the injector is reduced. That is, by using the valve body 46 as a magnet body, it is possible to estimate the amount of foreign matter collected by the magnet body due to a decrease in the injection performance, and it is possible to determine the appropriate replacement timing of the valve body or the flow limiter. . If only the portion of the valve body 43 where the communication hole 46 is formed is used as a magnet body instead of the entire valve body 43, foreign matters such as metal pieces and metal powder are concentrated in the vicinity of the communication hole 46 and collected. For this reason, there is a high correlation between the amount of foreign matter collected by the magnet body and a decrease in injection performance caused by the communication hole becoming narrow due to the foreign matter. Accordingly, it is possible to determine a more appropriate time for replacement of the valve body or the flow limiter.

Furthermore, as shown in FIG. 1, a differential pressure gauge 30 capable of measuring a differential pressure between the pressure of the high-pressure fuel supplied to the injector 4 and the pressure of the high-pressure fuel in the common rail 2 can be provided. When the amount of the foreign matter 100 collected in the vicinity of the communication hole 46 is increased, the flow area of the fuel passing through the communication hole 46 is narrowed due to the presence of the foreign matter 100, and the fuel injection performance from the injector 6 is expected to deteriorate.
Therefore, the amount of foreign matter 100 accumulated in the vicinity of the communication hole 46 can be estimated by measuring the differential pressure of the high-pressure fuel before and after passing through the communication hole 46 with the differential pressure gauge.

An appropriate replacement time for the flow limiter 4 can be determined by providing the differential pressure gauge and estimating the amount of the foreign matter 100.
Also, the differential pressure value measured by the differential pressure gauge 30 is taken into the ECU 18, and an alarm (not shown) is issued in response to an instruction from the ECU 18 when the differential pressure value exceeds a certain value. Can be surely informed.
The differential pressure gauge measures not only the pressure of the high-pressure fuel stored in the common rail 2 and the pressure of the high-pressure fuel supplied to the injector, but also the first embodiment and the first embodiment. The same applies to the embodiment according to Example 2.

  In addition, although embodiment based on Example 3 shown using FIG.5 and FIG.6 can also be implemented independently, it uses together with embodiment based on embodiment based on Example 1 or Example 2. FIG. You can also

  In a common rail fuel injection device comprising a common rail that stores fuel pressurized by a high-pressure pump, an injector that injects fuel stored in the common rail, and a control device that controls the operation of the high-pressure pump and the injector. The present invention can be used as a common rail fuel injection device that can reduce the amount of foreign matter such as metal pieces and metal powder that enter the injector.

2 Common rail 4 Flow limiter 6 Injector 8 High-pressure fuel pipe (flow path from common rail to injector)
10 High Pressure Pump 12 Fuel Tank 18 ECU (Control Device)
23 Plug 24a, 24b Magnet 41 Casing 42 Outlet 43 Valve body 44 Valve seat 45 Spring 46 Communication hole 47 Hollow part

Claims (6)

A common rail that stores high-pressure fuel pressurized by a high-pressure pump; an injector that injects fuel stored in the common rail into a combustion chamber of an engine; and a control device that controls operations of the high-pressure pump and the injector. In the common rail fuel injection device,
A common rail fuel injection device comprising a magnet body that adsorbs foreign matter by magnetic force at a position in the common rail or in a flow path from the common rail to the injector, where the high-pressure fuel stays.   The common rail type fuel injection device according to claim 1, wherein the magnet body is provided in a part removable from the common rail.   3. The common rail fuel injection device according to claim 2, wherein the magnet body is attached to a plug provided at a longitudinal end portion of the common rail, or the plug is formed of a magnet body. For piping connecting the common rail and the injector,
A casing, a fuel outlet formed in the casing, a valve body that has a hollow portion and receives pressure of the fuel flowing into the hollow portion from the common rail, and slides in the casing; and formed in the casing A valve seat having a shape in which the valve body can be seated, an elastic body arranged in the casing and pressing the valve body away from the valve seat, and the hollow portion provided in the valve body, Providing a flow limiter having a communication hole communicating with the outlet;
4. The common rail fuel injection device according to claim 2, wherein at least a part of the flow limiter is formed of a magnet body.   The common rail type fuel injection device according to claim 4, wherein a portion constituting the communication hole of the valve body is formed of a magnet body.   5. The common rail fuel injection according to claim 1, further comprising a differential pressure gauge for measuring a differential pressure between a pressure of the high pressure fuel stored in the common rail and a pressure of the high pressure fuel supplied to the injector. apparatus.

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