KR20210089667A - Fluid metering valve - Google Patents

Abstract

In particular, the fluid metering valve 1 used as a fuel injection valve for directly injecting fuel into a combustion chamber of an internal combustion engine includes a valve needle 15 and an electromagnetic actuator 2, wherein the electromagnetic actuator 2 is a solenoid coil. (3), and an armature (4) disposed on the valve needle (15), wherein the solenoid coil (3) is wound around a coil carrier (63). The coil carrier 63 is formed at least substantially of at least one metallic material.

Description

Fluid metering valve

FIELD OF THE INVENTION The present invention relates to valves for metering fluids, in particular fuel injection valves for internal combustion engines. In particular, the present invention relates to the field of injectors for fuel injection systems of motor vehicles, in which fuel is preferably injected directly into the combustion chamber of an internal combustion engine.

DE 103 60 330 A1 is known from a fuel injection valve for a fuel injection system of an internal combustion engine. A known fuel injection valve comprises a valve needle cooperating with a valve seat surface to form a sealing seat, and an armature connected to the valve needle, the armature acting in a closing direction by a return spring and cooperating with a solenoid coil. The solenoid coil is encapsulated in a coil housing and wound around a coil carrier, the coil carrier being seated on an inner pole. An electrical plug contact surrounded by a molded plastic coating on the inner pole is provided on the solenoid coil.

A valve according to the invention with the features of claim 1 has the advantage that improved design and function are possible. In particular, the spraying behavior can be improved.

A desirable improvement of the valve presented in claim 1 is possible by means of the measures presented in the dependent claims.

In a preferred embodiment of the valve, the electromagnetic actuator is provided with an armature connected to the valve needle, said armature not being fixedly connected to the valve needle, but rather mounted in an overhang manner between two stops provided on the valve needle. In this case, an axial play is specified between the armature and the two stops, which is called the armature free travel distance. Since the armature can be held at the combustion chamber-side stop by the armature free-moving spring at rest, it is preferable that when the actuator is subsequently activated and the armature is actuated, the total armature free travel distance can be used as the acceleration distance.

This embodiment with the armature free travel has a number of advantages. Due to the impact of the armature during opening, the valve needle can be reliably opened even at a higher fuel pressure with the same magnetic force, indicating a mechanical boost. Also, because the moving mass can be separated so that the stopping force is split into two pulses, seat wear is reduced. Also, using a valve that is very dynamic by the separation of the mass can lower the bounce tendency.

The valve is preferably used for metering a liquid fluid, in particular a liquid fuel. Gasoline or mixtures comprising such gasolines are particularly suitable as fuel. Here, the expression fuel should be understood generically, and in particular, the fuel may have a specific moisture content. The embodiments and advantages described in relation to fuel are correspondingly shown in the case of fluids as well. The fuel is preferably injected directly into the combustion chamber of the internal combustion engine. Fuel may be supplied through an inlet connection, where the fuel first passes through the inlet channel and then into the armature space. After the fuel has passed through the armature space, the fuel reaches a sealing seat formed between the valve seat face and the valve closing body, which can be actuated by the valve needle.

In a preferred development according to claim 2, a housing part is provided which can be connected, for example, to the inlet connection. In this case, the inlet channel can extend partly through the inlet connection and partly through the housing part. The liquid fuel passing through the inlet channel forms a heat sink. The heat generated by the solenoid coil during operation can be dissipated to the heat sink via the coil carrier which is a good heat conductor.

Thus, malfunction can be prevented even if significant energy loss in the form of heat in the solenoid coil occurs. In particular, melting of the insulating varnish of the wire of the solenoid coil can be prevented. Also, the solenoid coil is usually partially surrounded by plastic, in particular a plastic encapsulation. Since heat can be dissipated through the coil carrier, plastic damage, for example due to premature aging, can also be avoided. Thus, the sealing of the solenoid coil can be ensured during its service life, in particular water cannot penetrate into the solenoid coil. As a result, the desired protection against possible corrosion and/or frost damage is achieved.

Thus, on the one hand, the function of the actuator is maintained during its service life. But on the other hand, the heat dissipation through the coil carrier in the respective application allows for heavy loading of the solenoid coil. For example, a solenoid coil can be excited with a higher current to achieve a higher magnetic force. Due to this, a further increase in the magnetic force and thus the opening force acting on the valve needle can be achieved. This allows in particular higher system pressures, in particular higher fuel pressures.

A preferred embodiment of the housing part is possible according to claim 3 . In this case, the inner electrode may be connected to the inlet connection. An inlet channel may extend through the inlet connection and the inner pole to lead to the armature space. Also, the valve needle may be guided at the inner pole. A preferred implementation of thermal contact between the coil carrier and the housing part is possible according to the improvement according to claims 4 and/or 5 . However, in a variant embodiment, indirect contact of the coil carrier to the housing part is also possible, for example by means of heat-conducting means. According to a preferred improvement according to claim 6, a reliable fixation of the coil carrier and a favorable heat transfer can be achieved.

According to a preferred development according to claim 7, heat can be dissipated from the coil carrier into the fluid through the one or more housing parts. In this case, the heat can optionally be first released from one housing part to another housing part and then to the fluid, in particular the fuel.

A preferred embodiment of the housing part, in particular a further housing part, is possible according to claim 8 . According to an improvement according to claim 9, heat can be dissipated into the fuel as it passes through the armature space. A preferred implementation of the coil carrier is presented in claim 10 . This allows the heat loss of the solenoid coil to be effectively dissipated into the cooler fuel. Also, the solenoid coil may be partially surrounded by a plastic encapsulation. Such plastic capsules are generally highly heat resistant. However, with the proposed coil carrier, the energy loss can be dissipated and thus damage to the plastic capsule can be prevented. In this case, the coil wire is wound on a metal coil carrier in an appropriate manner. Then, for example, a plastic capsule can be molded into a metal coil carrier. A thermal bridge to the fuel remains through the metal coil carrier, resulting in effective coil cooling. The coil carrier can be adjusted for each contact part, in particular for the inner pole and/or the separating ring.

Preferred embodiments of the present invention are explained in more detail in the following description with reference to the accompanying drawings.

1 is a partial schematic cross-sectional view of a valve according to a preferred embodiment of the present invention;

1 shows a valve 1 for metering a fluid according to a preferred embodiment in a partial schematic cross-sectional view. The valve 1 can in particular be designed as a fuel injection valve 1 . A preferred application is a fuel injection system in which the fuel injection valve 1 is designed as a high-pressure injection valve 1 and is used to inject fuel directly into the corresponding combustion chamber of an internal combustion engine. The design of the valve 1 is particularly suitable for liquid fluids, in particular for liquid fuels such as gasoline or diesel, a liquid mixture with at least one fuel and, if necessary, a water component can also be used.

The valve 1 comprises an electromagnetic actuator 2 , which comprises a solenoid coil 3 , an armature 4 and an inner pole 5 . When the solenoid coil 3 is energized, the magnetic circuit 6 is closed via the inner pole 5 , as a result of which the armature 4 opens along the longitudinal axis 8 of the housing (valve housing) 9 . It is operated in direction (7). Here, the housing 9 includes a valve seat body 10 and housing portions 11 to 14 . The housing part 13 forms the inner electrode 5 in this embodiment.

The armature 4 is arranged on the valve needle 15 , in this embodiment the armature 4 is mounted on the valve needle 15 in an overhang manner. For this purpose, stops 16 , 17 are provided on the valve needle 15 , said stops 16 , 17 being fixedly arranged on the valve needle 15 . The stops 16 , 17 can be designed as parts 16 , 17 connected to the valve needle 15 and/or integrally with the valve needle 15 . Stop faces 18 , 19 facing the armature 4 are formed at the stops 16 , 17 , so that the stop faces 18 , 19 are fixedly arranged relative to the valve needle 15 .

For the armature 4 , the armature free travel distance 20 is specified. When the armature 4 is actuated, the armature 4 first passes the armature free travel 20 until the armature 4 touches the stop surface 19 . The armature 4 then takes the valve needle 15 in the opening direction 7 . Consequently, a larger opening pulse can be used to open the valve 1 . When the valve 1 is opened, the valve closing body 21 connected to the valve needle 15 is raised from the valve seat surface 22 formed on the valve seat body 10, so that the valve closing body 21 and the valve seat surface The sealing sheet 23 formed between 22 is opened. Then, the fuel can be injected from the inner space 24 of the housing portion 11 of the valve housing 9 to the combustion chamber of the internal combustion engine or the like through the nozzle holes 25 and 26 formed in the valve seat body 10. have.

When the valve 1 is opened, the armature 4 strikes the stop face 27 formed in the housing part 13 , ie the inner pole 5 in this embodiment. The stop face 27 limits the movement of the armature 4 relative to the valve housing 9 . To close the valve 1 , the power to the solenoid coil 3 is cut off, and the valve needle 15 is moved back to the starting position shown in FIG. 1 by a closing spring (return spring) 30 . Here, the armature 4 is moved opposite the opening direction 7 through the stop 17 by the valve needle 15 . In the closed state, the starting position shown in FIG. 1 of the armature 4 , in which the armature 4 rests on the stop surface 18 , is ensured via the armature free-moving spring 31 .

Thus, the valve needle 15 can be actuated against the force of the return spring 30 by the actuator 2 to open the valve 1 . In this case, the valve needle 15 is guided. A valve needle guide 32 is provided on the valve seat body 10 . Further guidance can also be provided, for example, by means of a stop 17 , which is guided in the bore 33 of the housing part 13 , ie the inner pole 5 . A plurality of through openings 34 are provided in the valve needle guide 32 , the through openings 34 being illustratively shown in FIG. 1 . A plurality of through openings 35 are provided in the stop 17 used as a valve needle guide, the through openings 35 being illustratively shown in FIG. 1 .

The valve 1 has an inlet connection 40 connected to a housing 9 . The inlet connection 40 has an axial bore 41 . The valve 1 has an inlet channel 42 formed in part by a bore 41 and partly by a bore 33 . The fuel supplied through the inlet connection 40 flows into the armature space 43 through the inlet channel 42 , and the fuel passes through the stop 17 at the through opening 35 . The fuel may pass through the armature space 43 through a plurality of armature bores 44 and annular gaps 45 formed in the armature 4 , the annular gap 45 forming the armature 4 and the housing 9 . is formed between the inner (inner wall) 46 of the After the armature space 43 , the fuel enters the interior space 24 . Accordingly, when the sealing sheet 23 is opened, fuel can be supplied, as shown by the flow arrows 50 to 53, among which the flow arrows 50 to 53 are illustratively shown. have. The fuel is thus guided in particular along the bore 33 of the housing part 13 and the inner side 46 of the housing 9 .

The housing part 12 connected to the housing part 11 is designed as a separating ring 60 . Here, the inner side 46 defining the armature space 43 is partially formed in the separating ring 60 . A thermal contact 61 is created between the separating ring 60 and the inner pole 5 , said thermal contact 61 being realized, for example, via a contact surface 62 , preferably designed in the form of a cylinder jacket. . The solenoid coil 3 is wound on a coil carrier 63 . The coil carrier 63 is formed from one or more metallic materials having at least substantially high thermal conductivity. The coil carrier 63 , the separating ring 60 and the inner pole 5 have thermal contacts 64 , 65 between the coil carrier 63 and the inner pole 5 or between the coil carrier 63 and the separating ring 60 . are designed to be formed on and placed on each other. The thermal contacts 64 , 65 can be implemented, for example, via contact surfaces 66 , 67 each preferably designed in the form of a cylinder jacket. With respect to the longitudinal axis 8 , the contact surfaces 62 , 66 , 67 extend axially and preferably completely circumferentially. In this embodiment, the coil carrier 63 is arranged partly on the inner pole 5 and partly on the separating ring 60 . Here, the coil carrier 63 may be pressed against the inner pole 5 and/or the separation ring 60 . Thus, there is a possibility of forming a direct contact between the coil carrier 63 and the inner pole 5 or the separating ring 60 . However, in a variant embodiment, contact means with high thermal conductivity may also be used.

The heat loss that occurs when the solenoid coil 3 is energized is at least substantially absorbed by the coil carrier 63 and dissipated through the inner pole 5 and the separating ring 60 to the fluid used as a heat sink. Here, heat transfer to the fluid takes place in the region of the inlet channel 42 and in the region of the armature space 43 .

Because the coil carrier 63 circumferentially surrounds the inner pole 5 and the separating ring 60 , large contact surfaces 66 , 67 are achieved which enable optimized heat dissipation. By pressing the coil carrier 63 against the inner pole 5 and/or the separating ring 60 , additional contact surfaces can be avoided, thus reducing the effective thermal resistance between the coil carrier 63 and the fluid. Since the fluid flows through the housing 9 upon actuation of the valve 1 , the desired tracking of the fuel acting as a coolant is made upon actuation of the valve needle 15 . A plastic capsule 68 for the solenoid coil 3 is molded into the coil carrier 63 .

The invention is not limited to the described embodiments.

1: valve
2: Actuator
3: Solenoid coil
12, 13: housing part
15: valve needle
42: inlet channel
43: armature space
60: separation ring
63: coil carrier
66: contact surface
68: plastic capsule

Claims (10)

A valve for fluid metering (1), in particular a fuel injection valve for directly injecting fuel into a combustion chamber of an internal combustion engine, comprising a valve needle (15) and an electromagnetic actuator (2), said electromagnetic actuator (2) comprising a solenoid coil ( 3), and an armature (4) arranged on the valve needle (15), wherein the solenoid coil (3) is wound on a coil carrier (63), wherein:
A valve, characterized in that the coil carrier (63) is formed at least substantially of at least one metallic material. The method of claim 1,
At least one housing part (12, 13) is provided, the coil carrier (63) is at least partially arranged in the housing part (12, 13), an inlet channel (42) is provided, the fluid is provided during operation Passing through the inlet channel (42), the coil carrier (63), during operation, the cooling of the coil carrier (63) through the housing (12, 13) to the fluid passing through the inlet channel (42) A valve, characterized in that it is arranged in the housing part (12, 13) so as to be made possible by 3. The method of claim 2,
At least one housing part 13 is designed as the inner pole 5 of the actuator 2 and/or the coil carrier 63 circumferentially surrounds the housing part 13 and/or the inlet channel ( 42) is formed at least partially in said housing portion (13). 4. The method according to claim 2 or 3,
The valve, characterized in that the coil carrier (63) sits directly on the housing part (13) at the contact surface (66). 5. The method of claim 4,
Said contact surface (66) extends circumferentially along and about said longitudinal axis (8) and/or said contact surface (66) is at least partially designed in the form of a cylinder jacket valve to. 6. The method according to any one of claims 2 to 5,
and the coil carrier (63) is pressed or welded to the housing (12, 13). 7. The method according to any one of claims 2 to 6,
A further housing part (12) is provided, on which the coil carrier (63) is arranged at least partially, the further housing part (12) being, during operation, the housing part (13) and characterized in that it partially circumferentially surrounds the housing part (13) such that cooling of the coil carrier (63) through the further housing part (12) is made possible by the fluid passing through the inlet channel (42). valve. 8. The method according to any one of claims 2 to 7,
A valve, characterized in that at least one housing part (12) is designed, at least in part, as a separating ring (60). 9. The method of claim 8,
An inner wall (46) defining an armature space (43) is formed at least in part in the housing part (12) designed as a separating ring (60), the fluid passing through the armature space (43) during operation valve to. 10. The method according to any one of claims 1 to 9,
The coil carrier 63 is at least substantially formed of a preferably non-ferromagnetic material having high thermal conductivity and/or the coil carrier 63 is at least partly a copper-based metal material and/or at least partly an aluminum-based metal. A valve, characterized in that the solenoid coil (3) is partially surrounded by a plastic capsule (68) formed of a material and/or connected to the coil carrier (63).

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