DE102012223212A1 - Fuel injector for use in motor vehicles, has electrical connector that is configured for energizing actuator formed of laminated electro-active polymers - Google Patents

Abstract

The injector (10) has a pair of actuator (18,88) for actuating a needle-shaped valve element (30) and an electrical connector (12) for energizing the actuators. The actuators are formed of laminated electro-active polymers including conductive polymers, ionic metal-polymer composites and ionic gels dry electro-active polymers such as electrostrictive polymers, piezoelectric polymers and ferroelectric polymers from a stack structure. The actuators are rigidly connected to an actuator head or an actuator foot at the respective fastening points of an injector (14).

Description

State of the art

Most of the actuators currently used with individual fuel systems are either piezo actuators or solenoid valves. With such actuators needle-shaped valve elements, also referred to as a nozzle needle, directly or indirectly driven and switched.

US 2009/0250021 A1 refers to a control device for a fluid in which electroactive materials are used. At the US 2009/0250021 A known solution, a fluid control device comprises a valve seat. By means of an actuator made of electroactive polymers, a sleeve-shaped switching element is actuated, which changes a distance between one end of the sleeve and the valve seat.

Disclosure of the invention

The present invention has for its object, on the one hand to reduce the manufacturing cost of a fuel injector for injecting fuel and on the other hand to realize longer switching paths for a needle-shaped valve element and to shorten the switching times of such an actuator under certain circumstances. Furthermore, the injection course can be defined defined.

According to the invention, a fuel injector is proposed, which comprises an actuator for actuating a needle-shaped valve element, wherein the actuator has an electrical connection for energizing and the actuator for actuating the fuel injector is formed from electroactive polymers.

The electroactive polymer actuator can either be designed such that a number of electroactive polymers are stacked in a stacked arrangement, or the actuator is formed from electroactive polymers from a rolled or wound array of electroactive polymers. Among the electroactive polymers are ionic (wet) electroactive polymers, e.g. conductive polymers, ionic metal-polymer composites and ionic gels, etc., as well as electronic (dry) electroactive polymers such as e.g. electrostrictive polymers and piezoelectric polymers include ferroelectric polymers and dielectric elastomers / polymers, etc.

The inventively proposed production of the actuator of electroactive polymers, in contrast to piezoceramics, which expensive materials such. Lead zirconate titanate require relatively inexpensive polymers are used here. When using electroactive polymers for the production of actuators can be long switching paths for a direct control of the needle-shaped valve element realize, which is not possible with piezo actuators due to the small size. In a direct control of the needle-shaped valve element, the injection profile can be formed. This means that the movement speed and the direction of movement of the needle-shaped valve element during the entire movement can be controlled directly by controlling the driving voltage of the actuator of electroactive polymers. Furthermore, the use of electroactive polymers allows significantly shorter switching times of fuel injectors, compared to solenoid valves and resulting very low injection rates. The actuators made of electroactive polymers used according to the invention are soft, in contrast to piezoceramics, which are quite brittle. This feature offers tremendous benefits in a rugged environment. Furthermore, electroactive polymers are very easy to miniaturize, and can be switched silently. This eliminates disturbing Klackergeräusche a piezo or a Magnetinjektors, were previously operated with the fuel injectors for motor vehicles. Due to the fact that the electroactive polymers have elastic properties, the needle-shaped valve element can be pressed into the valve seat without destroying this component.

In a possible embodiment variant of the fuel injector proposed according to the invention, the actuator made of electroactive polymers can be enclosed by a heat-shrinkable tube, coated in a fuel-resistant manner or introduced into a metal sleeve. The actuator of electroactive polymers is optionally non-positively, material or positively connected to the actuator base of an attachment point with an injector of the fuel injector.

In the inventively proposed fuel injector, this extends through a free space on a low pressure side of the fuel injector, which is bounded by the injector to the outside. Between the actuator of electroactive polymers and the needle-shaped valve member, i. the nozzle needle of the fuel injector, on the one hand, a direct connection, for example in the form of a cohesive connection such as a welded joint exist; On the other hand, it is also possible that the needle-shaped valve element, i. the nozzle needle indirectly actuates the needle-shaped valve element via a coupler module by changing the pressure in a control chamber.

In the former alternative, the actuator is firmly connected with a coupler piece or the actuator head connected to the needle-shaped valve element, wherein the connection is rigid.

The actuator of electroactive polymers may be supported via a spring element at the bottom of a cavity of the fuel injector.

The needle-shaped valve element itself, or a coupler piece of the coupler module can be guided in an intermediate disc, on which in turn a closing spring is supported, which forms the needle-shaped valve element i. the nozzle needle is acted upon in the closing direction. The mentioned closing spring can act in an advantageous embodiment of the inventively proposed fuel injector on a shim, which is provided for adjusting the opening force on the needle-shaped valve member. The actuator of electroactive polymers can be embedded in a filler, which is located in a metal sleeve. This sleeve is closed by a membrane or a bellows, so that the filler or the filling material remains within the free space between the actuator of electroactive polymers and the inside of the metal sleeve of the actuator module. The actuator module is located in the injector housing of the fuel injector.

In a further advantageous embodiment of the fuel injector proposed according to the invention, the actuator made of electroactive polymer can be surrounded by a plastic coating, in particular fluorosilicone, fluororubber and / or parylene and / or a heat-shrinkable tube. The actuator made of electroactive polymers may be rigidly joined to its actuator head at a connection either with an end face of the needle-shaped valve element directly or with an end face of the coupling piece.

Advantages of the invention

Preferably, the inventively proposed actuator is formed of electroactive polymers in a stacked arrangement, wherein a plurality of thin layers formed are stacked. An advantage of the electroactive polymer actuator proposed according to the invention is the fact that the direction of movement of such an actuator in a stacked arrangement is the same as the opening direction of the needle-shaped valve element, i. the nozzle needle. Therefore, it is possible to dispense with coupler modules or valves for otherwise necessary reversal of the direction of movement. The inventively proposed actuator of electroactive polymers contracts when energized. On the one hand, in the solution proposed according to the invention, it is possible to connect the needle-shaped nozzle element directly to the actuator module in order to obtain a direct switch. This eliminates the need for an additional valve to control. It can be realized with such a trained actuator relatively large strokes, which has an extremely low noise level during operation. Furthermore, the actuator proposed according to the invention can be formed encapsulated from electroactive polymers, also a coating or the use of a shrink tube are possible. Furthermore, the inventively proposed actuator of electroactive polymers is more elastic than actuators, which are made of piezoceramic; Therefore, a seat damage by hitting the needle-shaped valve element in the valve seat is not to be feared.

The activation of the inventively proposed actuator made of electroactive polymers is carried out by a control device which controls or regulates the voltage and thus the speed of movement of the needle-shaped valve element during the entire opening and closing movement of the needle-shaped valve element. With the inventively proposed actuator of the electroactive polymer pressures up to 100 MPa can be generated. An actuator designed as a wound actuator could also be used in existing systems that are operated for example by piezoelectric actuators, and replace them which would entail a cost advantage.

Brief description of the drawings

With reference to the drawing, the invention will be described below in more detail.

It shows:

1 the illustration fuel injector for injecting fuel, with wound actuator of electroactive polymers in the low pressure region,

2 a section through a further embodiment of the fuel injector with indirect control of the needle-shaped valve element, by a high-pressure side arranged actuator of electroactive polymers,

3 a further embodiment variant of the fuel injector proposed according to the invention, in which the needle-shaped valve element is directly actuated by the high pressure actuator made of electroactive polymers,

4 A further embodiment variant of a fuel injector, with a separate high-pressure bore in the injector housing, in which the needle-shaped valve element is actuated directly by a low pressure actuator made of electroactive polymers,

5 an embodiment variant of the fuel injector proposed according to the invention, in which the high-pressure actuator made of electroactive polymers is supported in a free space by means of a spring,

6 an embodiment variant of the fuel injector proposed according to the invention, in which a low-pressure actuator made of electroactive polymers is coupled directly to the needle-shaped valve element without the interposition of a supporting spring element and the injector housing is traversed by a feed guide,

7 a variant of the present invention proposed fuel injector without supporting spring element analogous to 5 but without

Support of the spring element, with high pressure actuator made of electroactive polymers,

8th an embodiment of the actuator of electroactive polymers embedded in a filler or a sealant in a metal sleeve,

9 an actuator of electroactive polymers, in a wound embodiment,

10 a variant of an actuator of electroactive polymers in a stacked arrangement with a plurality of electroactive polymer elements, which is enveloped by a fuel-resistant coating or by a shrink tube and

11 a wound arrangement of an actuator of electroactive polymers, enclosed by a fuel-resistant coating or a shrink tube.

variants

The representation according to 1 is to take a schematic view of a section through a fuel injector.

The in 1 illustrated fuel injector 10 includes an electrical connection 12 with which one in an injector housing 14 arranged actuator of electroactive polymers 18 is controlled. At the actor 18 For example, it is either a rolled or a wound actuator 88 according to a variant according to 9 or 11 , With these actors 88 These are those that lengthen when energized in the axial direction. The injector housing 14 also includes a return port 16 , is returned via the return amount in a fuel tank. Furthermore, the in 1 illustrated fuel injector 10 a high pressure inlet 20 that goes through the injector housing 14 extends, on a coupler module 22 over to a switching valve 24 , The switching valve 24 is a throttle plate 26 , The throttle plate 26 is located above a nozzle module 28 in which a needle-shaped valve element 30 , that is, the nozzle needle is arranged.

The nozzle module 28 is by means of a nozzle retaining nut 32 via a threaded connection with the injector housing 14 together.

2 shows a section through an embodiment of the present invention proposed fuel injector actuated by an actuator in a stacked arrangement of electroactive polymers, with indirect actuation of a needle-shaped closure element.

Out 2 it turns out that the fuel injector 10 an electrical connection 12 and an injector housing 14 includes, in which the actor 18 from electroactive polymers. This is applied in the in 2 illustrated embodiment a coupler piston 34 , The coupler piston 34 is by a coupler spring 38 supported, in turn, on a coupler sleeve 36 supporting the coupler piston 34 surrounds. Below the coupler sleeve 36 is the washer 26 or the throttle plate, in which a throttle 40 arranged and a high pressure inlet bore are executed. When opening the throttle 40 becomes a control room 42 relieved of pressure, leaving an end face of the control room 42 protruding needle-shaped valve element 30 depressurized and the needle-shaped valve element, ie the nozzle needle 30 a valve seat at the combustion chamber end of a nozzle body 46 releases and therefore fuel can be injected into the combustion chamber of the internal combustion engine.

Below the washer 26 there is a spring plate 44 , The spring plate 44 limited with the washer 26 the control room 42 , On the spring plate 44 a nozzle closing spring is supported 48 from which the needle-shaped valve element, ie the nozzle needle 30 acted upon in the closing direction, so that when not energized the actuator 18 from electroactive polymers, the needle-shaped valve element 30 That is, the nozzle needle remains permanently seated, the injection openings therefore remain closed and no fuel is injected into the combustion chamber of the internal combustion engine.

In the embodiment according to 2 is the needle-shaped valve element 30 in a first needle guide 70 and a second needle guide 72 guided. It is possible, the needle-shaped valve element 30 also lead only in a single needle guide.

In contrast to 2 shows 3 a direct actuation of a needle-shaped valve element by an actuator of electroactive polymers.

From the illustration according to 3 it turns out that the fuel injector 10 the actor 18 from electroactive polymers. In the in 3 illustrated embodiment is the actuator 18 of electroactive polymers from a shrink tube 58 enclosed. The actor 18 comprises a number of layered elements of electroactive polymers stacked together 60 are arranged. The actor 18 from the electroactive polymers, enclosed here by a shrink tube 58 , controls the needle-shaped valve element 30 ie the nozzle needle directly on, because actuator 18 from electroactive polymers 18 via a coupler piece 50 directly with the needle-shaped valve element, ie the nozzle needle 30 is coupled. Instead of the jacket of the actuator 18 through the stocking hose 58 There is also the possibility of this with a fuel-resistant coating 92 to be provided or encapsulated by a metallic component. This means that a longitudinal movement, ie a contraction of the actuator 18 from electroactive polymers when energized directly in the axial direction in an opening movement of the needle-shaped valve element 30 can implement, ie, the injection openings at the combustion chamber end of the fuel injector 10 be opened.

As further from the sectional view according to 3 shows, the actuator extends 18 from electroactive polymers - here, for example, enclosed by the shrink tube 58 - through a hollow or free space 76 , Via a fuel connection 20 Under system pressure, fuel enters the free space 76 and flows over in a washer 26 executed fuel bores 56 a nozzle body 46 to. At the combustion chamber end of the nozzle body 46 are the injection openings, which is injected with appropriate release by the needle-shaped valve element, under system pressure standing fuel in the combustion chamber of the internal combustion engine.

How out 3 goes on, this is the shrink tube 58 enclosed actuator 18 of electroactive polymers at an attachment site 62 with the injector housing 14 of the fuel injector 10 connected. The actuator attachment 62 is rigid, so the actuator 18 from electroactive polymers with appropriate current through the electrical connection 12 performs a contraction movement such that upon contraction of the actuator 18 from electroactive polymers through the coupler piece 50 in the washer 26 guided needle-shaped valve element 30 ascends in the vertical direction and at the combustion chamber end of the nozzle body 46 trained injection ports are free. As 3 it can be seen further, the leadership of the coupler piece takes place 50 through a highly accurate hole formed in the washer 26 is executed. Instead of the shrink tubing 58 can also be a fuel-resistant coating 92 or a metallic encapsulation of the actuator 18 be made. Also in the embodiment according to 3 is the needle-shaped valve element 30 in a first needle guide 70 and a second needle guide 72 guided. Of course, there is also the possibility of the needle-shaped valve element 30 only in a needle guide in the nozzle body 46 respectively.

The representation according to 4 is a variant of the present invention proposed fuel injector refer to, in which the injector has a housing formed in a channel high-pressure bore which extends through the injector.

Also in the embodiment according to 4 is the actuator 18 from electroactive polymers in the free space 76 passing through the injector housing 14 is limited. Also in the illustration according to 4 is the actor 18 of electroactive polymers in a stacked arrangement 60 formed and in this embodiment of a shrink tube 58 surround. The energization of the actuator 18 made of electroactive polymers via the electrical connection 12 at the top of the fuel injector 10 , The open space 76 by the actor 18 from electroactive polymers, furthermore has a system-related return connection 16 from a low pressure area.

As 4 can be further removed, is the shrink tube 58 enclosed actuator 18 from electroactive polymers by a spring element 64 supported. The spring element 64 supported on the one hand on the actuator head 66 on the other hand on the floor of the open space 76 coming from the injector housing 14 is enclosed. In the embodiment according to 4 form the actor 18 from electroactive polymers, the coupler piece 50 , which at the Aktorkopf 66 is fixed, and the needle-shaped valve element 30 ie the nozzle needle, an interconnected unit. In the embodiment according to 4 can the coupler piece 50 and the actuator head 66 For example, be materially joined together, as well the facing end faces of the coupler piece 50 and the needle-shaped valve element 30 ie the nozzle needle. The upper portion of the needle-shaped Ventilementes 30 is in the washer 68 led, which is essentially the washer 26 the embodiment according to the 2 and 3 equivalent.

The needle-shaped valve element 30 is in the embodiment according to 4 in a first needle guide 70 and a second needle guide 72 led in 4 are indicated only schematically. The two needle guides 70 respectively. 72 are in the nozzle body 46 educated. Instead of in 4 shown first needle guide 70 and the second needle guide 72 There is also the possibility here, the needle-shaped valve element 30 only in a single, in the nozzle body 46 to guide provided needle guide. Also in the embodiment according to 4 has the free space 76 who is essentially the actor 18 from electroactive polymers, via a return port 16 , The actor 18 of electroactive polymers may instead of a shrink tube 58 also with a fuel-resistant coating 92 or a metallic component. An actuator base 80 is at an attachment point 63 this embodiment by a press fit / sealing seat in the injector 14 added. Although the needle-shaped valve element 30 in this embodiment in 2 needle guides 70 respectively. 72 is guided, there is also the possibility that needle-shaped valve element 30 in a single needle guide in the nozzle body 46 respectively.

In contrast to the embodiment according to 4 , in which the inlet bore through the injector housing 14 extends, is in the embodiment according to 5 the high pressure inlet 20 at the top of the injector housing 14 and flows into the open space 76 , In this is the actor 18 encapsulated from electroactive polymers and optionally coated, or with a shrink tube 58 Mistake. Also in the embodiment according to 5 is located on the actuator head 66 the spring element 64 to which the actor 18 supported by electroactive polymers. The representation according to 5 is an attachment of the actuator 18 from electroactive polymers through the compound 63 , For example, given a press / seal connection.

The actor 18 of electroactive polymers is in the embodiment according to 5 exposed to the pressurized fuel in the cavity 76 through the high pressure inlet 20 flows.

Also in the embodiment according to 5 can instead of two needle guides 70 respectively. 72 , only a needle guide in the nozzle body 46 be provided.

In the embodiment according to 5 it is an actor 18 of electroactive polymers, in layered arrangement 60 is executed. At the actuator head 66 is the coupler piece 50 absorbed by material.

The needle-shaped valve element 30 is in the first needle guide 70 and the second needle guide 72 of the nozzle body 46 at the combustion chamber end of the fuel injector 10 guided. The washer 68 , at which the spring element 64 is supported, with one or more fuel passage holes 56 Mistake. At the open space 76 of the fuel injector 10 is a return connection 16 provided over which any leaking minor leakage quantities are discharged into the low-pressure part of the fuel injection system, which is not absolutely necessary.

6 shows a variant of the present invention proposed fuel injector in which it lacks a spring element to support the actuator in the free space.

As shown in the illustration 6 is apparent, is the actor 18 from electroactive polymers to the actuator attachment 62 of the injector housing 14 added. The actor 18 of electroactive polymers extends substantially through the space 76 , which has a return connection 16 for possibly occurring small leakage quantities. The leakage quantities reach via the return connection 16 in the low pressure part of the fuel injection system. The energization of the actuator 18 made of electroactive polymers via the electrical connection 12 , Through the injector housing 14 extends a high-pressure inlet channel, which in the washer 68 opens and from there the cavity of the nozzle body 46 pressurized with system pressurized fuel. In the nozzle body 46 is beyond that the closing spring 48 picked up, located at the bottom of the washer 68 supported and on the other hand at the periphery of the needle-shaped valve element 30 arranged shim 74 , Analogous to the in 4 and 5 illustrated embodiments of the present invention proposed fuel injector, the needle-shaped valve element 30 in the first needle guide 70 or additionally a second needle guide 72 led, both in the nozzle body 46 of the fuel injector 10 are formed.

In the embodiment according to 6 is the actuator head 66 of the actor 18 of electroactive polymers fixed to the coupler piece 50 connected in turn, which in turn via a cohesive connection with the on the coupler piece 50 opposite end face of the needle-shaped valve element 30 is coupled. When energizing the actuator 18 of electroactive polymers in a stacked arrangement 60 over the electrical connection 12 the actor pulls himself 18 composed of electroactive polymers, so following this contraction movement, both the coupler piece 50 and the associated needle-shaped valve element 30 perform an axially upward movement and the combustion chamber end of the nozzle body 46 release arranged injection openings. The actor 18 is about a screw connection 62 with the injector housing 14 rigidly connected to the actuator 18 supporting spring element 64 deleted for this reason.

As shown in 7 a variant of the fuel injector is shown, which essentially according to the embodiment according to 6 equivalent.

In contrast to the representation according to 6 has the fuel injector 10 according to the execution in 7 not over yourself through the injector housing 14 consistently up to the washer 68 extending high-pressure inlet 20 , Rather, the high pressure feed opens 20 in the open space 76 of the fuel injector 10 from the injector housing 14 is formed and enclosed. Via the return connection 16 If necessary, small leakage quantities are diverted to the low-pressure side of the fuel system. Analogous to the representation according to 6 it lacks in the embodiment according to 7 also on a spring element which the Aktorfuß 66 of the actor 18 supported by electroactive polymers. In the in 7 illustrated embodiment is the actuator 18 from electroactive polymers not by a spring element 64 supported, but in the upper part of the injector 12 either by means of the screw connection 62 attached, or there alternatively via a material connection to the injector 18 connected. In the case of energization, the actuator pulls 18 composed of electroactive polymers, so that with the interposition of the coupler piece 50 the opening of the needle-shaped valve element 30 he follows.

The actuator head 66 is with a coupler piece 50 connected, which in turn connected to the upper end face of the needle-shaped valve element 30 communicates. In the washer 68 the upper part of the needle-shaped valve element is guided, while its lower part in the first needle guide 70 and the second needle guide 72 of the nozzle body 76 is guided. The the combination of actuator 18 from electroactive polymers, coupler piece 50 and needle-shaped valve element 30 acting closing spring 48 pushes the composite in the valve seat to the combustion chamber end of the nozzle body 46 so that formed there injection ports are closed. Only with energization and corresponding contraction of the actuator 18 from electroactive polymers drives the needle-shaped valve element 30 from his seat, gives the combustion chamber end of the nozzle body 46 trained injection ports freely, so that fuel can be injected into the combustion chamber of the internal combustion engine. Also in the embodiment according to 7 can instead of two needle guides 70 respectively. 72 only a needle guide in the nozzle body 46 be provided.

In the 8th . 9 . 10 and 11 are further embodiments of the actuator of electroactive polymers 18 shown without the fuel injector 10 , in which the actuator of electroactive polymers is used, is shown. Regarding the fuel injector 10 is based on those already described above 1 - 7 directed.

The representation according to 8th is an embodiment of an actuator module of electroactive polymers refer to, which is surrounded by a metal sleeve and embedded in a filler or a sealant, such as silicone.

With reference number 82 is a filler or a sealant such as silicone called, in the free space, by the metallic sleeve 84 is limited, is included. The injector housing 14 includes the electrical connection 12 for actuating the actuator 18 from electroactive polymers. The actuator foot 80 is with the metal sleeve 84 cohesively connected, for example, welded. At the the Aktorfuß 80 opposite end, ie the actuator head 66 , is a membrane or a bellows 86 that the filler 82 or the sealant 82 encapsulates. In the embodiment according to 8th is the actuator of electroactive polymers of several thin electrode layers in a stacked arrangement 60 built up. The metallic sleeve 84 can the electrical elastomers and the filler 82 enclose, in which the thin electrode layers of the stack assembly 60 of the actor 18 are embedded from electroactive polymers. Preferably, the membrane is 86 or the bellows 86 with the actuator head 66 and the sleeve 84 cohesively connected, so for example welded.

9 shows a further embodiment of the inventively proposed actuator of electroactive polymers, wherein the actuator is wound from a dielectric elastomeric film and expands when energized in the longitudinal direction.

A coiled or rolled actuator 88 from electroactive polymers, as in 9 shown is, is made of dielectric elastomeric film 90 educated. Also in the embodiment according to 9 is a lot of a filler 82 or a sealant 82 such as silicone included. The metal sleeve 84 is already related to that 8th mentioned bellows 86 or the membrane 86 capsuled. At the top of the metallic sleeve 84 is the electrical connection 12 , which is the energization of the actuator 18 . 88 from electroactive polymers according to the embodiment in 9 serves. With the actuator foot 80 is the actor 88 made of wound dielectric elastomeric film 90 with the metallic sleeve 84 rigidly connected, and may, for example, advantageously in the fuel injector according to 1 be used.

The representations according to the 10 and 11 are taken from wound or stacked trained actuators of electroactive polymers, which are enclosed by a fuel-resistant coating and / or a shrink tube.

So shows, for example 10 an actuator made of electroactive polymers 18 that of a fuel-resistant coating 92 and / or a shrink tube 58 can be enclosed. The actor 18 of electroactive polymers as shown in FIG 10 is in stacking arrangement 60 executed. The actuator foot 80 opposite is the actuator head 66 , At the upper end, ie at the actuator base 80 of the actor 18 from electroactive polymers, is the electrical connection 12 , When energizing the actuator 18 of electroactive polymers, this pulls together and operated - as already explained above - with the interposition of the coupler piece 50 the needle-shaped valve element 30 either directly or indirectly.

11 finally shows the actor 88 in rolled or wound training. The rolled or wound trained actuator 88 of electroactive polymers, for example a dielectric elastomeric film 90 , can also be a fuel-resistant coating 92 and / or a shrink tube 58 include and is also by one at the Aktorfuß 80 arranged electrical connection 12 energized. When energizing the actuator 18 from electroactive polymers in rolled or wound construction 88 The actor lengthens himself 18 in the axial direction and operated as related to 1 already described, a switching valve or a rocker or the like to the direction of movement in an opening movement of the actuator 18 to reverse in a direction opposite to the opening of injection ports.

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

• US 2009/0250021 A1 [0002]
• US 2009/0250021 A [0002]

Claims (15)

Fuel injector ( 10 ), an actor ( 18 . 88 ) for actuating a needle-shaped valve element ( 30 ), with an electrical connection ( 12 ) for energizing the actuator ( 18 . 88 ), characterized in that the actuator ( 18 . 88 ) is formed from electroactive polymers. Fuel injector ( 10 ) according to claim 1, characterized in that the actuator ( 18 ) from a stack arrangement ( 60 ) layered electroactive polymers is formed. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 88 ) is formed from a rolled or wound arrangement of electroactive polymers. Fuel injector ( 10 ) according to any one of the preceding claims, characterized in that electroactive polymers, ionic (wet) electroactive polymers, such as conductive polymers, ionic metal polymer composites and ionic gels, dry electroactive polymers, such as electrostrictive polymers, piezoelectric polymers, ferroelectric polymers, dielectric Elastomers / polymers include. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 18 . 88 ) of electroactive polymers on the actuator head ( 66 ) or on the actuator base ( 80 ) at a first attachment point ( 62 ) with an injector housing ( 14 ) of the fuel injector ( 10 ) is rigidly connected, or at a second attachment point ( 63 ) with the injector housing ( 14 ) is connected as a press, shrink or sealing seat. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 18 . 88 ) by a free space ( 76 ) on a low pressure side of the fuel injector ( 10 ), wherein the injector housing ( 14 ) a high-pressure inlet ( 20 ) having. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 18 . 60 . 88 ) by a free space ( 76 ) on a high-pressure side of the fuel injector ( 10 ) and a fuel feed ( 20 ) into the open space ( 76 ) opens. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 18 . 88 ) with the needle-shaped valve element ( 30 ) by means of a connection ( 50 ) 78 ) is directly connected, or the needle-shaped valve element ( 30 ) indirectly via a coupler ( 34 ) by changing the pressure in a control room ( 42 ). Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 18 . 88 ) via a spring element ( 64 ) at the bottom of the free space ( 76 ) is supported. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the needle-shaped valve element ( 30 ) or a coupler piece ( 50 ) in a washer ( 68 ) are guided, at which a closing spring ( 48 ) is supported. Fuel injector ( 10 ) according to the preceding claim, characterized in that the closing spring ( 48 ) on a shim ( 74 ), which is used to adjust the opening force on the needle-shaped valve element ( 30 ) is provided. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 18 . 88 ) of electroactive polymers into a filler ( 82 ) embedded in the open space ( 76 ) within a metal sleeve ( 84 ), which through a membrane or a bellows ( 86 ) is closed. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 18 . 88 ) of electroactive polymers from a fuel-resistant coating ( 92 ), in particular of fluorosilicone, fluororubber and / or parylene, and / or of a heat-shrinkable tube ( 58 ) is surrounded. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 18 . 88 ) on its actuator head ( 66 ) on a connection ( 78 ) rigid either with an end face of the needle-shaped valve element ( 30 ) or an end face of the coupling piece ( 50 ) is joined cohesively. Fuel injector ( 10 ) according to one of the preceding claims, characterized in that the actuator ( 18 . 88 ) is inversely or bipolar operable.

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