DE102018209099A1 - Internal combustion engine with adaptive injection behavior - Google Patents

Abstract

The present invention relates to an Otto internal combustion engine comprising a spark plug (6) and injector for injecting fuel directly into a combustion chamber (9) of the internal combustion engine, the injector comprising: a one-piece closure element (2), a valve body (3), a first injection-orifice arrangement (101) in the valve body (3) with at least one first injection hole (31), a second injection-injection arrangement (102) in the valve body (3) with at least one second injection hole (32), the first injection-injection arrangement (101) of the second injection-injection arrangement (102) is displaced in the axial direction of the injector by a predetermined distance (A), a first sealing seat (4) between the closing element (2) and the valve body (3), and a second sealing seat (5) between the closing element (2) and the valve body (3), which is arranged in the axial direction of the injector between the first and second spray hole arrangement (101, 102), wherein the second sealing seat (5) in the axial direction a cylindrical sealing surface having a predetermined length (L), in order to achieve a stepped injection of the fuel in the opening case of the injector, wherein the injector is arranged in the internal combustion engine such that a central axis (XX) of the injector at an acute angle (α) is arranged to a central axis (YY) of a cylinder (8) of the internal combustion engine, and wherein the acute angle (α) in a range of 30 ° ≤ α <90 °.

Description

State of the art

The present invention relates to an Otto internal combustion engine with an injector for the direct injection of fuel into a combustion chamber in a lateral installation position.

Injectors for internal combustion engines are known from the prior art in different embodiments. In Otto internal combustion engines, in which there are lower injection pressures compared to diesel internal combustion engines, injectors are known with a plurality of injection holes, which are usually in a plane perpendicular to a central axis of the injector. In this case, injection angles of the individual injection holes can be varied in order to produce different spray patterns. From the WO 2006/040283 A1 , of the DE 10 2015 223 437 or the DE 10 2010 063 355 A1 In each case, an injector for a diesel internal combustion engine is known in which injection holes are arranged one above the other in two spray-hole rows. In this case, only one sealing seat is present between a needle and a valve body. When the needle is opened from the sealing seat, fuel is injected through the two spray-hole rows. In this case, there is always a pairwise injection of fuel through the superposition arrangement of the injection holes of the two injection hole rows. Due to different angles of the injection holes of the two spray-hole rows, a higher penetration depth of the fuel spray jets into the highly compressed combustion chamber of the diesel internal combustion engine can be achieved. As a result, advantages can be obtained in the diesel combustion.

For conventional Otto engine combustion methods, an increased penetration depth is not expedient due to the comparatively lower back pressure, in particular during the intake stroke injection. In the application for gasoline engines, the goal is to avoid by a corresponding spray breakup and its interaction with the charge movement, wall contact of injected fuel and to achieve a homogeneous mixture composition as possible.

Disclosure of the invention

The internal combustion engine according to the invention with an injector for injecting fuel with the features of claim 1 has the advantage that a combustion process of the internal combustion engine can be significantly improved, in particular less gaseous raw emissions (HC, CO and NOx raw emissions) as well Particulate emissions (soot) can be achieved. Particular advantages are achieved for combustion processes in which the ignition mechanisms are improved by means of ignition-coupled injection. This is inventively achieved in that the injector comprises a one-piece closing element and a valve body, are formed in which injection holes. In this case, a first injection-molding arrangement is provided in the valve body with at least one first injection hole, and a second injection-injection arrangement is provided in the valve body with at least one second injection-hole. The special arrangement of the injection holes is such that the first injection nozzle arrangement is offset from the second injection nozzle arrangement in the axial direction of the injector by a distance A. Furthermore, a first sealing seat and a second sealing seat is formed between the one-piece closing element and the valve body. In this case, the second sealing seat is arranged in the axial direction of the injector between the first spray-hole arrangement and the second spray-hole arrangement. The second sealing seat has in the axial direction of the injector on a cylindrical sealing surface with a predetermined length in order to achieve a stepped injection of the fuel in the opening case of the valve. As a result of the cylindrical sealing surface on the second sealing seat, when the closing element is opened, the first spray-hole arrangement is first released, so that fuel can be injected into a combustion chamber via the injection holes of the first injection-molding arrangement, and after the predetermined length at the second sealing seat has been replaced by the closing element that opens, the injection-holes become the second spray hole arrangement released and is injected via the injection holes of the second spray hole arrangement in the combustion chamber. Thus, a stepped injection can be achieved, wherein all the injection holes are preferably released only after a predefined stroke, in particular a full stroke of the one-piece closing element. Here, the injector is arranged in the internal combustion engine, that a central axis of the injector is arranged at an acute angle α to a central axis of the cylinder, wherein the acute angle α is greater than 30 °. This results in a lateral mounting position of the injector to the combustion chamber, whereby a completely different spray pattern than in comparison with the prior art, in which the injector is arranged substantially parallel to the central axis of the cylinder, is achieved. In particular, the lateral installation position makes it possible to provide a flammable, lean mixture in the combustion chamber and, in conjunction with the special injector according to the invention, an exact setting of an ignitable fuel mass in the region of the spark plug. Thus, it can be achieved that only the required fuel mass, which is necessary for the current load state, is injected. In addition to a fuel saving, this results in particular a significant reduction of raw emissions with corresponding advantages in the exhaust aftertreatment. It should be noted that in closed state of the first sealing seat completely seals. In the opening case, the second sealing seat is not quite tight due to the cylindrical guide. Since an axial length of the second sealing seat becomes smaller and smaller as the opening stroke continues, the second sealing seat acts like a variable throttle. Thus, the second sealing seat may also be referred to as a variable throttle seat. In the opening case leakage over the second sealing seat with increasing opening travel is always greater until then no radial overlap between the valve body and the cylindrical guide of the second sealing seat is more present and the second sealing seat opens completely.

The dependent claims show preferred developments of the invention.

The acute angle between the center axis of the cylinder and the center axis of the injector is preferably in a range of 45 ° to 87 °, in particular 60 ° to 80 °.

More preferably, at least one injection hole of the first spray hole arrangement is directed to a spark plug of the internal combustion engine. As a result, a flammable mixture can be reliably provided in the region of the spark plug. In particular, the amount of fuel can be provided via the at least one injection hole of the first spray hole arrangement only by a partial stroke of the injector, wherein the second injection nozzle arrangement decoupled via the second sealing seat does not participate in the injection and still remains closed.

According to a particularly preferred embodiment of the invention, all the injection holes of the first spray hole arrangement are directed to the spark plug.

More preferably, a number of spray holes of the first spray hole arrangement is smaller than a number of spray holes of the second spray hole arrangement. As a result, the main injection of fuel can take place via the second spray-hole arrangement. The first spray hole arrangement preferably serves to provide a flammable mixture in the region of the spark plug.

Preferably, the number of spray holes of the second spray hole arrangement is twice as large as the number of spray holes of the first spray hole arrangement. Preferably, the second spray hole assembly includes exactly six spray holes, and the first spray hole assembly includes exactly three spray holes.

Preferably, all spray holes of the first spray hole arrangement are arranged such that their spray hole axes intersect a ball having a diameter of 50 mm, wherein a center of the ball is located between a center electrode and a ground electrode of the spark plug. This ensures safe ignition of the mixture in the combustion chamber.

More preferably, the lateral mounting position of the injector is such that the injector, starting from a central axis of a cylinder of the internal combustion engine is disposed radially outside of intake valves and exhaust valves of the internal combustion engine. The injector is particularly preferably arranged laterally on a cylinder head of the internal combustion engine.

Preferably, the internal combustion engine further comprises a control unit, which is configured to carry out a lean burn process with an air ratio λ ≥ 1, preferably λ ≥ 2. The lean burn process is preferably carried out with a suction stroke injection and a compression stroke injection, wherein the compression stroke injection is preferably deposited only via the injection holes of the first spray hole assembly to provide an ignitable mixture at the spark plug.

Particularly preferably, a multiple injection takes place in the suction stroke and / or in the compression stroke.

In order to achieve a uniform distribution of the fuel in the combustion chamber, preferably the injection holes of the first spray hole arrangement in a first plane E1 arranged perpendicular to a central axis of the injector and the second injection holes of the second spray hole arrangement in a second plane E2 arranged perpendicular to the central axis of the injector. The first plane is spaced from the second plane by the distance A.

The first plane and the second plane are defined in such a way that all centers of the first injection holes at the entry location of the first injection holes are preferably in the first plane and all centers of the second injection holes at the entry location of the second injection holes are preferably in the second plane.

Preferably, the first sealing seat is a tapered sealing seat, in particular a conical sealing seat.

More preferably, the injector is an inwardly opening injector. That is, the closing member of the injector is retreated toward the injector interior to release the injection ports for the injection of fuel.

The gasoline engine preferably has injection pressures of 200 to 2000 × 10 ⁵ Pa, in particular 300 to 350 × 10 ⁵ Pa.

list of figures

• 1 eine schematische Schnittansicht eines Injektors gemäß einem ersten Ausführungsbeispiel der Erfindung mit einer Detailvergrößerung,
• 2 eine schematische Schnittansicht einer Brennkraftmaschine gemäß dem ersten Ausführungsbeispiel mit dem Injektor von 1,
• 3 eine schematische Ansicht der Brennkraftmaschine von 2, mit einem Zielbereich für einen Spraykegel der ersten Spritzlochanordnung,
• 4 ein schematisches Diagramm, welches ein Magerbrennverfahren der Brennkraftmaschine von 2 mit der eingespritzten Kraftstoffmenge M über einem Kurbelwinkel K zeigt,
• 5 eine schematische Teilschnittansicht einer Brennkraftmaschine gemäß einem zweiten Ausführungsbeispiel der Erfindung,
• 6 eine Draufsicht auf das Spraybild des Injektors von 4, und
• 7 eine schematische Darstellung des Spraybilds des Injektors von 6 bei geöffneter erster und zweiter Spritzlochanordnung in einer Ebene im Bereich einer Zündkerze.

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawing is:

• 1 a schematic sectional view of an injector according to a first embodiment of the invention with an enlarged detail,
• 2 a schematic sectional view of an internal combustion engine according to the first embodiment with the injector of 1 .
• 3 a schematic view of the internal combustion engine of 2 , with a target area for a spray cone of the first spray hole arrangement,
• 4 a schematic diagram showing a lean burn process of the internal combustion engine of 2 with the amount of fuel injected M above a crank angle K shows,
• 5 a schematic partial sectional view of an internal combustion engine according to a second embodiment of the invention,
• 6 a plan view of the spray image of the injector of 4 , and
• 7 a schematic representation of the spray pattern of the injector of 6 with open first and second spray hole arrangement in a plane in the region of a spark plug.

Preferred embodiments of the invention

The following is with reference to the 1 to 4 an internal combustion engine 100 with an injector 1 according to a first preferred embodiment of the invention described in detail. How out 1 and the detail enlargement of 1 can be seen, includes the injector 1 a one-piece closure element 2 , which is provided in the form of a needle.

The injector 1 further comprises a valve body 3 , wherein between the one-piece closing element 2 and the valve body 3 a first sealing seat 4 and a second sealing seat 5 is trained. How out 1 can be seen, are the first and second sealing seat 4 . 5 in the axial direction XX of the injector by a distance A spaced.

The first sealing seat 4 is a conical sealing seat between closing element and valve body and the second sealing seat 5 is a cylindrical sealing seat between closing element and valve body.

The injector 1 further includes a first spray hole arrangement 101 with first spray holes 31 and a second spray hole arrangement 102 with second spray holes 32 , In 1 is schematically only one injection hole of the two spray hole arrangements 101 . 102 located. As in detail, however, from the 2 can be seen includes the first spray hole arrangement 101 this embodiment less spray holes 31 as the second spray hole arrangement 102 ,

How out 2 can be seen, includes the spray hole arrangement 101 exactly one injection hole 31 which is a first spray club 11 generated. The second spray hole arrangement 102 includes two spray holes 32 and creates two spray lobes 21 . 22 ,

As in 1 shown is the spray hole 31 the first injection hole arrangement 101 in a first level E1 arranged. The spray holes 32 the second injection hole arrangement 102 are in a second level E2 arranged. How out 1 it can be seen, is the first spray hole arrangement 101 in this case by a distance A from the second spray hole arrangement 102 in the direction of the central axis XX spaced apart from the injector. The first and second levels E1 and E2 lie in each case in centers of the first and second injection holes on an inner side of the valve body 3 perpendicular to the central axis XX ,

How further from the 2 it can be seen, the injection directions of the injection holes of the first and second spray hole arrangement 101 and 102 each different. This results in no overlap of the spray lobe 11 the first spray hole arrangement and the spray lobes 21 . 22 the second injection hole arrangement 102 in top view of the spray image.

As further from the enlargement of 1 can be seen, the second sealing seat 5 in the direction of the central axis XX an axial length L on. Furthermore, the second sealing seat 5 as a cylindrical sealing surface in the direction of the central axis XX provided so that when opening the closing element 2 the closing element immediately from the first sealing seat 4 , which is designed as a tapered, in particular conical sealing seat lifts, but first still on the cylindrical second sealing seat 5 remains and seals there. Here, the cylindrical second sealing seat acts 5 as a cylindrical guide for the one-piece closing element 2 , Here is the second sealing seat 5 not completely tight, but some slight leakage occurs on the cylindrical inner circumference of the valve body 3 on, leaving the second sealing seat 5 is a kind of variable throttle seat.

As a result, the flow path for the fuel at first only for the first spray hole arrangement 101 with the first spray holes 31 Approved. Only after covering a predetermined path of the closing element is the second sealing seat 5 fully released and fuel will also flow through the spray holes 32 the second injection hole arrangement 102 , Only then does this result in 2 shown spray pattern with all spray lobes of the first and second spray hole arrangement. As long as a seal on the second sealing seat 5 takes place, results in a spray pattern only with the first spray lobe 11 , because only fuel through the spray hole 31 the first injection hole arrangement 101 in the combustion chamber 9 is injected. A leak over the second sealing seat can be neglected. The release of the second spray holes 32 can choose about an axial length of the tip of the sealing seat 5 complementary cylindrical end portion of the closing element 2 be set.

How out 2 is apparent, is the injector 1 on the internal combustion engine 100 directly to a combustion chamber 9 arranged. Furthermore, schematically are a piston 7 and a cylinder 8th and an inlet valve 15 and an exhaust valve 16 shown.

Here, the injector points 1 a lateral mounting position, in which a central axis XX of the injector at an acute angle α to a central axis YY of the cylinder 8th is. How out 2 can be seen, the acute angle α = 83 °.

The lateral installation position outside of a diameter, which includes the inlet valve and the outlet valve, now allows an injection of the fuel such that via the first injection nozzle arrangement 101 a sprayclaw 11 up to an ignition device in the form of a spark plug 6 enough. The spark plug 6 is centered in a cylinder head 80 the internal combustion engine 100 arranged.

The spray clubs 21 . 22 the second injection hole arrangement 102 are in the interior of the combustion chamber 9 directed, wherein a wall wetting of the cylinder or the cylinder head 80 is avoided.

By the orientation of the spray lobe 11 the injection hole 31 the first injection hole arrangement 101 is thus in the range of the spark plug 6 generates an ignitable mixture. As in 3 shown is a centerline ZZ the spray club 11 aligned so that the center line ZZ the spray club 11 a spherical area 60 around a center 61 cuts, with the midpoint 61 between a center electrode 62 and a ground electrode 63 the spark plug 6 lies. This will ensure that in the area of the spark plug 6 an ignitable mixture is present. A diameter of the ball 60 is about 50 mm.

2 shows the fully opened state of the injector 1 in which both the first and the second spray hole arrangement 101 . 102 is open.

Because the injector 1 also can only be partially opened, leaving only the first spray hole arrangement 101 is open, so targeted only one injection of an ignitable mixture for the area around the spark plug 6 be provided around. In this case, for example, first a main injection with fully opened injector 1 be made and shortly before an ignition an ignition injection with only partially opened injector 1 so only the spraycloth 11 is produced. In this way, in particular a very efficient lean burn process with an air ratio of λ> 1 can be realized.

Particular preference is given here in a compression stroke of the internal combustion engine via the first spray hole arrangement 101 only the fuel injected, which is active to improve ignition conditions in the area of the spark plug 6 leads. Thus, the first spray hole arrangement 101 provide ignition coupled spray cone.

The lateral mounting position of the injector in this case has the particular advantage that an area between the inlet valve 15 and the exhaust valve 16 is loaded with a component less, namely the injector, since in particular by the trend of downsizing of internal combustion engines, the space is getting smaller, especially in this area. Nevertheless, in this area still the spark plug 6 to be ordered.

By the possible stepped injection of fuel, different combustion methods can now be realized by means of the injector according to the invention.

4 shows an example of a diagram representing the injected amount of fuel M over the crank angle K. In 4 means the abbreviation OT "top dead center", where in 7 A distinction is made between the LOT (charge change upper dead center) and the ZOT (ignition upper dead center). UT means "bottom dead center".

For clarity, in the diagram of 4 two spray pictures S1 and S2 shown with differently opened closing element. After LOT, the injector is fully opened 1 so that the one-piece closing element 2 both from the first sealing seat 4 as well as from the second seal seat 5 is lifted off. This results in the spray image shown above the left part of the diagram S1 with spraycloths 11 . 21 . 22 , This is a first amount of fuel M1 injected. Here, an injection of fuel takes place almost to the bottom dead center UT, almost over the entire intake stroke.

4 shows a lean burn process with an air ratio of λ ≥ 2. Internal combustion engine is a 4-stroke engine, the intake stroke extends to bottom dead center UT. Subsequently, the compression stroke, wherein before reaching the ignition top dead center ZOT first a second fuel injection with a second amount of fuel M2 only over the spray hole 31 the first injection hole arrangement 101 takes place and then an ignition at the ignition Z , both before the ZOT. At the second injection time, only the first injection pattern will be used 101 open, leaving the second amount of fuel M2 significantly smaller than the first fuel quantity M1 , Subsequently, in a known manner, the power stroke and a Ausschiebetakt, which are no longer shown in the diagram for reasons of clarity.

Thus, in the lean burn process by means of a spark-coupled injection, the ignition conditions can be significantly improved. Furthermore, a targeted enrichment of the spark plug near area with fuel to improve the ignition conditions can be achieved.

To 4 It should be noted that in this case also a multiple injection is possible. This is in the 4 in the compression stroke by the reference numeral M2 ' indicated. So can in the 4 shown lean burn operation, for example, before and after the ignition Z one or more additional injections M2 ' be made. More preferably, the multiple injection in the intake stroke is possible.

According to an alternative method, a homogeneous combustion method with an air ratio of λ = 1 can also be realized. In this case, in particular, an adjustment of the quantity of injected fuel by a complete opening (eg at full load) or at an idling or lower part load range only by opening the first spray hole arrangement 101 be achieved.

The 5 to 7 show an injector 1 and an internal combustion engine 100 according to a second embodiment of the invention. In contrast to the first embodiment, the internal combustion engine 100 of the second embodiment, a number of spray holes 32 the second injection hole arrangement 102 which is larger than a number of the injection holes 31 the first injection hole arrangement. Exactly how out 7 it can be seen has the first spray hole arrangement 101 three spray holes 31 on, leaving three spray lobes 11 . 12 . 13 when opening the first spray hole arrangement 101 result. The second spray hole arrangement 102 has exactly six spray holes, so that six spray lobes 21 . 22 . 23 . 24 . 25 . 26 result. 7 shows a section in a plane in the region of the spark plug 6 which schematically shows the spray cones generated in a fully opened injector 1 clarified.

Thus, the second spray hole arrangement 102 twice as many spray holes as the first spray hole arrangement 101 ,

The 5 and 6 show schematically the propagation of the spray lobes in the combustion chamber 9 with fully opened injector 1 , Here is in 5 and 6 the intake stroke shown, with the intake valve 15 is open. The arrows B indicate the intake of combustion air into the combustion chamber 9 on. The three spray lobes 11 . 12 . 13 get into the area of the spark plug 6 whereas the six spray lobes 21 . 22 . 23 . 24 . 25 . 26 in the main area of the combustion chamber 9 extend. The lateral installation position of the injector 1 in the cylinder head 80 Thus, as in the first embodiment allows an active improvement of the ignition conditions in the region of the spark plug 6 by special, ignition-coupled spray lobes of the first spray hole arrangement 101 , This allows a targeted provision of a flammable lean mixture to the spark plug 6 be achieved.

Thus, by both embodiments described selectively only the fuel can be injected into the combustion chamber, which is required for a combustion process depending on the respective load condition. As a result, fuel is saved and also the raw emissions of the internal combustion engine can be significantly reduced. The advantages can be transferred to all Brennverfahrens aspects in which a spark-coupled injection is provided / necessary. These include u.a. the lean burn processes shown, stratified combustion processes, homogeneous compression ignition ignition assist and catalyst heating operation.

Furthermore, by the application of the invention, the support of the cylinder inner flow and charge movement is possible. For this purpose, the arrangement of the injector would preferably be mounted on the inlet side in order to promote a tumble flow.

It should also be noted for all described embodiments that Otto engine combustion method in conjunction with the injector according to the invention 1 can be significantly improved. In particular, in a gasoline engine, a higher injection pressure up to 2000 × 10 ⁵ Pa can be used.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2006/040283 A1 [0002]
• DE 102015223437 [0002]
• DE 102010063355 A1 [0002]

Claims (11)

Otto internal combustion engine, comprising a spark plug (6) and an injector for injecting fuel directly into a combustion chamber (9) of the spark-ignition internal combustion engine, the injector comprising: a one-piece closure element (2), a valve body (3), a first injection-molding arrangement (101) in the valve body (3) with at least one first injection hole (31), a second injection-orifice arrangement (102) in the valve body (3) with at least one second injection hole (32), wherein the first spray-hole arrangement (101) is offset from the second spray-hole arrangement (102) in the axial direction of the injector by a predetermined distance (A), - A first sealing seat (4) between the closing element (2) and the valve body (3), and a second sealing seat (5) between the closing element (2) and the valve body (3), which is arranged in the axial direction of the injector between the first and second injection-orifice arrangement (101, 102), - wherein the second sealing seat (5) in the axial direction has a cylindrical sealing surface with a predetermined length (L) in order to achieve a stepped injection of the fuel in the opening case of the injector, - wherein the injector is arranged in the Otto internal combustion engine such that a central axis (X-X) of the injector at an acute angle (α) to a central axis (Y-Y) of a cylinder (8) of the Otto internal combustion engine is arranged, and - wherein the acute angle (α) in a range of 30 ° ≤ α <90 °. Otto internal combustion engine after Claim 1 , wherein the acute angle (α) is in a range of 45 ° to 87 °. Otto internal combustion engine according to one of the preceding claims, wherein at least one spray hole (31) of the first spray hole arrangement (101) is directed in the direction of the spark plug (6). Otto internal combustion engine after Claim 3 , Wherein all the injection holes (31) of the first spray-hole arrangement (101) are directed in the direction of the spark plug (6). Otto internal combustion engine according to one of the preceding claims, wherein a number of spray holes of the first spray hole arrangement (101) is smaller than a number of spray holes (32) of the second spray hole arrangement (102). Otto internal combustion engine after Claim 5 , wherein the number of spray holes of the second spray hole arrangement (102) is twice as large as the number of spray holes of the first spray hole arrangement (101). Otto internal combustion engine after one of Claims 3 to 6 , wherein all spray holes of the first spray hole arrangement (101) are arranged in such a way that spray hole axes (ZZ) of the spray cones (11, 12, 13) generated by the first spray holes comprise a sphere (60) with a diameter of 50 mm about a center point (61). the ball intersect, the midpoint (61) between a center electrode (62) and a ground electrode (63) of the spark plug (6). Otto internal combustion engine according to one of the preceding claims, wherein the injector (1), starting from a central axis (Y-Y) of the cylinder (8) is arranged radially outside of an intake valve (15) and radially outside of an exhaust valve (16). Otto internal combustion engine according to one of the preceding claims, further comprising a control unit, which is configured to perform a lean burn process with an air ratio of λ ≥ 1, in particular λ ≥ 2, perform. Otto internal combustion engine after Claim 9 wherein the control unit is set up to open the injector (1) in such a way that during a suction stroke the injection holes of the first and second spray-hole arrangement (101, 102) are opened and only the spray-holes (31) of the first spray-hole arrangement (101) during a compression stroke are open. Otto internal combustion engine after Claim 10 wherein the control unit is configured to open the injector such that only the injection holes of the first injection nozzle arrangement are opened before and / or after ignition (Z) by the spark plug (6).

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