WO2018046191A1

WO2018046191A1 - Fluid injector for a motor vehicle

Info

Publication number: WO2018046191A1
Application number: PCT/EP2017/069542
Authority: WO
Inventors: Janos Radeczky; Vincent Dian
Original assignee: Continental Automotive Gmbh
Priority date: 2016-09-06
Filing date: 2017-08-02
Publication date: 2018-03-15
Also published as: DE102016216871A1

Abstract

The invention relates to a fluid injector (1) for a motor vehicle, comprising an actuator (3), a nozzle needle (9), and a throttle plate (5) with a first, second, and third recess (51, 52, 53) which are hydraulically coupled together. The first recess (51) is equipped with a piston (7) which is coupled to the actuator (3) in order to convert a movement of the actuator into a movement of the nozzle needle (9) by interacting with a lifting element (10). The third recess (53) is equipped with a control valve (20) which closes a hydraulic path (55) in the throttle plate (5) and prevents a flow of fluid through the path (55) in a first state and otherwise releases the flow of fluid. The lifting element (10) is arranged within the throttle plate (5) and extends from the first recess (51) to the third recess (53) through the second recess (52) such that the first and the second state of the control valve (20) can be adjusted in a specified manner by means of the actuator (3) and the lifting element (10).

Description

description

Fluidinj ector for a motor vehicle The invention relates to a Fluidinj ector for a motor vehicle, which is inexpensive to manufacture and provide an ^¬ reliable operation and a precise metering of fluid possible. Internal combustion engines are often designed to produce high torques requiring large injection quantities. On the other hand, legal regulations regarding the permissible pollutant emissions of internal combustion engines, which are arranged in motor vehicles, require various measures to be taken by which pollutant emissions are kept low. One

The starting point here is to be able to meter a fluid required as fuel as accurately as possible and to reduce the pollutant emissions generated by the internal combustion engine. The reduction of pollutant emissions from internal combustion engines and accurate metering of a metered fluid are in the construction of Fluidinj injectors a great challenge. It is necessary to take into account a variety of parameters in order to enable reliable and precise operation of the fluid injector.

It is an object of the invention to provide a Fluidinj ector for a motor vehicle, which is inexpensive to produce and which allows reliable operation and precise metering of fluid and which helps to minimize pollutant emissions in an internal combustion engine ^¬ . The problem is solved by the features of independent Pa ^¬ tentanspruchs. Advantageous embodiments are specified in the subclaims. According to a first aspect of the invention, a fluid injector for a motor vehicle comprises an actuator which is designed to axially move a nozzle needle relative to a longitudinal axis of the fluid injector. The Fluidinj ektor further includes a

Throttle plate having a first, a second and a third recess, which are hydraulically coupled to each other. Within the first recess of the throttle plate, a piston is arranged, which is coupled in cooperation with a lever element for translating a movement of the actuator in a movement of the nozzle needle with the actuator. In addition, the fluid injector comprises a control valve which is disposed within the third recess of the throttle plate and which is adapted to close in a first state a hydraulic path in the throttle plate and to prevent fluid flow through the hydraulic path and in a second state Fluid flow through the hydraulic path release. In addition, the fluid injector comprises the lever element, which is arranged within the throttle plate and extends from the first recess through the second recess into the third recess. The lever element couples the piston to the control valve, so that by means of the actuator and the lever element of the first and second state of the control valve is preset adjustable.

The described Fluidinj ector allows reliable operation and precise metering of fluid in a combustion chamber of an internal combustion engine and contributes to

Keep pollutant emissions in the engine low. Due to the design and arrangement of the control valve and the lever element in the throttle plate, additional components be saved nents, so that the described structure of the fluid injector is economically feasible.

For example, it is possible to dispense with the use of an additional valve plate with pressure limiting valve, which requires further follow-up costs as an actuator. A beneficial pressure control and pressure limiting function is integrated by the interaction of the lever member and the control valve in the throttle plate, so that a space-saving design of the described Fluidinj ector can be realized.

By means of the fluid injector, a reliable system and injection performance can be achieved with reduced design costs since it is possible to dispense with separate pressure regulating and pressure limiting valves. Such additional AK- tuatoren cause associated component costs in a construction of a Fluidinj ector and require additional investment ^¬ titionen among other things due to a required expanded leakage line, an associated control electronics and a corresponding electrical connection to a respective control device. By means of the described structure of the fluid injector, such costs can be avoided in a design of the fluid injector. The lever element is integrated in the throttle plate and acts with a leverage on the control valve, so that a space-saving and beneficial valve function can be realized, which can contribute to a reliable and accurate operation of the fluid injector. The lever element is inserted, for example, in a predetermined bore of the throttle plate, so that in a construction of the fluid injector, the design of the throttle plate takes place in coordination with the lever element. Relative to a pivot point of the lever member allows the interaction of the actuator on one side of the lever member and the control valve on the other side of the lever member an advantageous pressure control and pressure limiting the fluid pressure within the fluid injector. The at least one pivot point of the lever element provides a degree of freedom with respect to the interpretation of force relationships and allows the formation of a predetermined force to act on the control valve. The lever element acts on both sides of the cooperating components due to the pivot point, so that a force component which acts in the control pressure chamber on the control valve is transmitted to the actuator.

The control pressure chamber or control pressure range is located inter alia in the third recess of the throttle plate, while the high-pressure chamber is located, inter alia, in the region of the nozzle needle. In addition, a low-pressure space of the fluid injector is usually formed in the region of the actuator. By means of the described Fluidinj ector and the two-sided power transmission through the lever element, which extends from the first to the third recess of the throttle plate, adaptation methods can be used beneficially, for example, allow reliable detection of a closing time ^¬ point of the nozzle needle. Thus, the lever member further contributes to an advantageous of the fluid injector.

Thus, by means of the described construction of the fluid injector, in particular the lever element and control valve integrated in the throttle plate, a reliable and space-saving

Pressure control and pressure limiting function feasible and it is contributed to a cost-effective design of the Fluidinj ectors. According to one embodiment of the fluid injector, the he ^¬ belelement has a pivot point, in the region of the He ^¬ belelement is formed so that it seals the first recess against the third recess of the throttle plate.

In this way, by means of a predetermined configuration of the lever element in the region of its pivot point, the space between the control valve and the actuator can be reliably sealed in order to contribute to an advantageous operation of the fluid injector. The area of the pivot point is located for example in the second recess of the throttle plate and adapted in its shape and its material for a reliable sealing against an adjoining ^¬ wall of the throttle plate, so that this area is given the first and the third recess of the throttle plate from each other. A possible mating clearance between this sealing region of the lever element and the facing, inner wall of the throttle plate is for example about 10 ym. Thus, a controlled leakage can be anticipated and it is counteracted pressure waves that arise when an opening of the control valve and a

Bottom plate of the piezoelectric actuator can meet. Thus, a contribution to an improved quality of the sensor ability of the piezo-electric actuator ^¬ can be done by means of targeted training of the lever member.

According to a further development of the fluid injector, the control valve is arranged and designed such that it is apparent with respect to a longitudinal axis of the hydraulic path in a direction from a first axial end of the hydraulic path to a second axial end of the hydraulic path. In this case, the first axial end of the nozzle needle faces and faces away from the second axial end of the hydraulic path of the nozzle needle. According to one embodiment, the fluid injector comprises a biasing element which is arranged in the first recess of the throttle plate and is coupled to the piston with the He ^¬ belelement opposite. The biasing element exerts a predetermined force on the lever element in the direction of the piston, so that when the actuator is not actuated, the first state of the control valve is formed so that the control valve is realized in a closed position. According to a further development of the fluid injector, the biasing element comprises a spring. For example, the fluid injector is formed as a servo-piezoelectric fluid injector in which the control valve is closed in a non-driven state of the piezoelectric actuator. In such a closed state of the control valve is a

Avoid permanent leakage, which can cause an unwanted pressure equalization between the high pressure area in which the nozzle needle is arranged, and the control pressure range in which the control valve is arranged.

By means of the biasing element, such a closed state of the control valve can be realized by the pre ^¬ clamping element is designed and arranged so that it exerts a predetermined force on the control valve and it drives to take its closed position. The piezoelectric actuator thus opens the control valve according to the ^¬ be written arrangement against the force of the biasing member, wherein emanating from a storage chamber fluid pressure medium-supportive through associated sealing surfaces of the control valve.

A coil spring realizes a simple and inexpensive possibility of a biasing member to exert a constant force on the lever member and thereby to the control valve transfer. The biasing element is designed as a closing spring, for example, so that in an error case, the fluid pressure within the fluid injector is limited. Such Def ^¬ Hi or may be represented as unwanted, continuous delivery of a fluid pump, for example, which is coupled to supply the ector ector Fluidinj with fluid at the Fluidinj. In such a case, the control valve described limits the fluid pressure by the control valve is pressed against the spring force of the closing spring, thus allowing a distribution of the built-up fluid pressure. Such Druckbegren ^¬ limiting function of the control valve is characterized ^¬ it enables in particular, that the control valve opens in a direction facing away from the nozzle needle or the high pressure region. In this way, by means of the control valve integrated in the throttle plate, a separate pressure limiting valve can be saved in the fluid injector, which additionally requires additional electronic control and connections.

According to a further embodiment of the fluid injector, the lever element has a first lever arm and a second lever arm, wherein the first lever arm is coupled to the piston and the second lever arm to the control valve. In further embodiments, one or more further lever arms may be arranged between the first and the second lever arm, so that a lever system is formed with a plurality of pivot points, which allows a useful pressure control of the fluid pressure in the fluid injector.

According to a development of the fluid injector, a third state of the control valve is adjustable by means of the actuator, which forms a defined partial lift of the control valve between the closed, first state and the open second state. Such a controlled trained Teilhub can be beneficial to a pressure balance between affect the various pressure ranges and beneficially affect the functionality of the Fluidinj ectors.

By opening the control valve to a predetermined partial lift fluid from the high-pressure region, which is coupled to the nozzle needle, are selectively controlled. After the CONT ^¬ erventil is opened to a predetermined partial stroke, the pressing force on the control valve breaks down. As a result, the actuator experiences an increased counterforce, thereby setting a stable state of the lever member and the control valve and reducing a risk of an uncontrollably large pressure reduction of the fluid pressure in the control space. In this way it is possible to use the fluid injector for the controlled pressure reduction of the fluid pressure in the entire working range without inadvertently injecting fluid into a combustion chamber of an internal combustion engine. The described Fluidinj ector thus enables a robust and reliable operation and realizes a precise metering of fluid even at relatively high fluid pressures, for example, above 800 bar.

Embodiments of the invention are explained in more detail below with reference to the schematic drawings. Show it:

1 shows an embodiment of a fluid injector in a schematic sectional view,

FIG. 2 shows a detailed view of a section of the fluid injector according to FIG. 1, FIG. 3 shows a further detailed view of the section of the fluid injector according to FIG. 1.

Elements of the same construction or function are identified across the figures with the same reference numerals. Out For reasons of clarity, not all of the illustrated elements may be identified in associated figures with associated reference numerals. Figure 1 illustrates in a schematic sectional view of an embodiment of a fluid injector 1, which comprises an injector 63 and a nozzle body 68 which is coupled to the injector 63. Within a recess of the injector body 63, which is bounded along a longitudinal axis L of the fluid injector 1 by a wall of the injector body 63, a piezoelectric actuator 3 is arranged, which is coupled to a nozzle needle 9 to move them relative to the longitudinal axis L axially and in a closed position of the nozzle needle 9 to prevent fluid flow through the fluid injector 1 and otherwise release.

The piezoelectric actuator 3 is coupled to an electrical connection 60 of the fluid injector 1, which is designed for the energetic supply and control of the actuator 3. The fluid injector 1 further comprises a throttle plate 5, within which a lever member 10 and the control valve 20 are integrated.

As will be explained with reference to the following FIGS. 2 and 3, by means of the lever element 10 and control valve 20 a reliable and safe operation of the fluid injector 1 as well as precise metering of fluid in a combustion chamber of an internal combustion engine can be realized. In addition, by means of the fluid injector 1, a contribution is made to a cost-effective design and low emissions of pollutant emissions in an internal combustion engine.

In addition, a high-pressure bore 64 of the Fluidinj ector 1 is illustrated, which is the Fluidinj ektor 1 with a memory or Rail space coupled and allows supplying the Fluidinj ector 1 with fluid.

Figure 2 illustrates in a schematic sectional view of an enlarged view of the dashed bounded Be ^¬ realm of Fluidinj ector 1 of Figure 1 comprising the Dros ^¬ selplatte 5 with the lever member 10 and the control valve 20th On the basis of this schematic representation of the throttle concept of Fluidinj ector 1 can be seen, which comprises the outwardly opening control valve 20 which allows in cooperation with the lever member 10 and the actuator 3 a reliable and beneficial operation of the fluid injector 1 ector.

The throttle plate 5 has first, second and third recesses 51, 52 and 53 coupled together for fluid communication. The actuator 3 is coupled to a first lever arm 11 of the lever element 10 by means of a piston 7 which extends into the first recess 51. On a side of the first lever arm 11 opposite the piston 7, a biasing element 24 is arranged in the first recess 51 and exerts a predetermined force on the lever element 10. The pre ^¬ clamping element 24 is realized as a helical spring and acts with a constant spring force in the z direction on the lever member 10th

The lever element 10 extends from the first recess 51 through the second recess 52 into the third recess 53 of the throttle plate 5. In the second recess 52, the lever element 10 has a pivot point 14. The lever element 10 further has a second lever arm 12, which extends from the pivot point 14 into the third recess 53 and is coupled to the control valve 20. In this way, by means of the lever member 10, a force transmission between the actuator 3 and the biasing member 24 on the one hand and the control valve 20th on the other hand educable. In this way, an advantageous pressure control and pressure limitation of the fluid pressure within the Fluidinj ectors 1 can be realized, which can be beneficial effect on the injection performance of the fluid injector 1 and a precise metering of fluid.

The control valve 20 has a valve element 22 and is arranged in the third recess 53 of the throttle plate 5. In a first state, the control valve 20 is closed and prevents fluid flow through a hydraulic path 55 in the throttle plate 5. The valve element 22 acts with a valve seat, which is formed, for example, as a part of the inner wall of the throttle plate 5, and closes the hydraulic path 55 in the direction of the nozzle needle 9. In a second state, the control valve 20 is opened and a

Fluid flow through the hydraulic path 55 is released. In addition, if appropriate, one or more intermediate states can also be formed, in which the control valve 20 is partially opened and realizes a predetermined partial stroke. The states of the control valve 20 are predetermined by means of the actuator 3 and the lever member 10 adjustable.

In a non-controlled state of the piezoelectric actuator 3, the control valve 20 is closed due to the outgoing spring force from the biasing member 24. In the closed, first state of the control valve 20, a permanent leakage is avoided, which can cause an unwanted pressure equalization between the high pressure region in which the nozzle needle 9 is arranged, and the control pressure region in which the control valve 20 is arranged. When the piezoelectric actuator 3 is activated, the control valve 20 opens according to the illus ^¬ trated embodiment against the spring force of the pre ^¬ clamping element 24, wherein the fluid pressure in the high pressure region assisting cooperates and the control valve 20 still opens up or outside.

In this context, the term "top" or "outside" denotes an opening direction of the control valve 20, which faces away from the nozzle needle 9. Stated another way, the control valve 20 is referred to as outwardly opening, since the opening direction is oriented with respect to a longitudinal axis A of the hydraulic channel 55 in the direction from a first axial end 551 to a second axial end 552 of the hydraulic channel 55. Stömungstechnisch the first axial end 551 of the SI ^¬ nozzle needle 9 is facing and facing away from the second axial end 552 of the nozzle needle. 9 The biasing member 24 realizes a simple and cost ^¬ favorable possibility to exert a constant force on the He ^¬ belelement 10 and thereby to the control valve 20th In this way, the fluid pressure within the fluid injector 1 can be limited by means of a configuration of the biasing element 24 and of the lever element 10 and of the valve body 22. Such a pressure limiting function is useful, for example in an error case, if an unwanted, continuous promotion of a fluid pump for supplying the Fluidinj ector 1 with fluid. The control valve 20 limits the fluid pressure in that the control valve 20 against the

Spring force biasing member 24 is pressed, thus allowing a distribution of the built-up fluid pressure. Such a pressure-limiting function of the control valve 20 is made possible, in particular, by the control valve 20 opening in the described direction upwards or outwards. Thus, a separate pressure relief valve, which is placed for example in a common rail system on the rail or storage space, as well as an additionally required elekt ^¬ ronic controls and connections can be saved, as the described Fluidinj ektor 1 has such functionality on ^¬ .

Moreover, the space between the control valve 20 and the actuator can be reliably sealed from 3 ^¬ means of predetermined configuration of the lever member 10 in the region of its pivot point 14, to further contribute to an advantageous operation of the Fluidinj ector. 1 The region of the pivot point 14 is in the second recess 52 of the throttle plate 5 so adapted to an adjacent inner wall of the throttle plate 5, that a reliable sealing of the spring chamber, in which the pre ^¬ clamping element 24 is arranged, from the control room, in which Control valve 20 is arranged. In this way, a controlled leakage between the first and third recesses 51 and 53 are vorgehsehen and it is counteracted pressure waves that arise when opening the control valve 20 and can meet the piezoelectric actuator 3. By means of a targeted design of the lever element 10, a contribution can therefore be made to an improved sensor capability of the piezoelectric actuator 3.

The Fluidinj ektor 1 allows due to the described structure and in particular the integrated in the throttle plate 5 lever member 10 and control valve 20, a reliable and space-saving pressure control and pressure limiting function and also contributes to a cost-effective design and reliable operation of the fluid injector 1 at. For example, it requires no separate valve plate and no additional actuators to realize appropriate valve functions.

FIG. 3 illustrates in a further schematic

A detailed view of the dashed in Figure 1 region of the fluid injector 1, which shows, for example, a view that is rotated to the view shown in Figure 2 by 90 °. Figure 3 shows Thus, a schematic sectional view along the throttle bores, in particular along the longitudinal axis A of the hyd ^¬ raulischen path 55. On the basis of this view, inter alia, the hydraulic coupling between the third recess 53 and the high pressure region of the nozzle needle 9 can be seen, by means of the lever member 10 and Control valve 20 and the actuator 3 and the biasing member 24 can be selectively influenced.

Reference sign list

1 fluid injector

3 actor

5 throttle plate

51 first recess of the throttle plate

52 second recess of the throttle plate

53 third recess of the throttle plate

55 hydraulic path of throttle plate

551 first axial end of the hydraulic path

552 second axial end of the hydraulic path

57 further recess of the throttle plate

7 pistons

9 nozzle needle

10 lever element

11 first lever arm

12 second lever arm

14 pivot point of the lever element

20 control valve

22 valve element

24 biasing element

60 electrical connection

63 Inj ector body

64 high pressure bore

68 nozzle body

A longitudinal axis of the hydraulic path

L longitudinal axis of the fluid injector

Claims

claims

Fluid injector (1) for a motor vehicle, comprising:

an actuator (3) which is designed to move a nozzle needle (9) axially relative to a longitudinal axis of the fluid injector (1),

- A throttle plate (5) which has a first, a second and a third recess (51, 52, 53), which are hydraulically ^¬ coupled to each other, wherein

- Within the first recess (51) a piston (7) is arranged, which coupled in cooperation with a lever element (10) for translating a movement of the actuator (3) in a movement of the nozzle needle (9) with the actuator (3) is

- Within the third recess (53) a control valve (20) is arranged, which is adapted to close in a first state, a hydraulic path (55) in the throttle plate (5) and a fluid flow through the hydraulic path (55) to stop and in a second state to release a fluid flow through the hydraulic path (55), and

- The lever member (10) within the throttle plate (5) is arranged and extending from the first recess (51) through the second recess (52) into the third recess (53) and the piston (7) with the control valve ( 20) coupled, so that by means of the actuator (3) and the lever element (10) of the first and second state of the control valve (20) is preset adjustable.

2. Fluidinj ector (1) according to claim 1, wherein the lever element (10) has a pivot point (14), in whose region the lever element (10) is formed so that it is the first Recess (51) against the third recess (53) of the throttle plate (5) seals.

A fluid injector (1) according to claim 1 or 2, wherein the control valve (20) is arranged and configured to be relative to a longitudinal axis (A) of the hydraulic path

(55) in a direction from a first axial end (551) of the hydraulic path (55) to a second axial end

(552) of the hydraulic path (55) is apparent, the first axial end (551) facing the nozzle needle (9) and the second axial end (552) facing away from the nozzle needle (9).

Fluid injector (1) according to one of claims 1 to 3, comprising

a biasing member (24) disposed in the first recess (51) of the throttle plate (5) and coupled to the lever (10) opposite the piston (7) and applying a predetermined force to the lever member (10) in the direction of Plunger (7) exerts, so that when not driving the actuator (3) of the first state of the control valve (20) is formed.

A fluid injector (1) according to claim 4, wherein the biasing member (24) comprises a spring.

Fluid injector (1) according to one of claims 1 to 5, wherein the lever element (10) has a first lever arm (11) and a second lever arm (12), wherein the first lever arm (11) with the piston (7) and the second lever arm (12) is coupled to the control valve (20).

Fluid injector (1) according to one of claims 1 to 6, wherein by means of the actuator (3), a third state of the control valve (20) is adjustable, which between the closed, first state and the open second state forms a defined partial lift of the control valve (20).