Actuator arrangement and fuel injector incorporating an actuator arrangement

Abstract: An actuator arrangement for use in a fuel injector of an internal combustion engine, including an inner core (40) comprising a collar (48) and a core region (44) having a plurality of laminates (140) stacked in the direction of a first lamination axis (LA) and a first outer pole (42) for receiving at least a part of the core region (44). An electromagnetic winding (52) is received within a first volume defined between the first outer pole (42) and the core region (44). The collar (48) is formed from at least two collar parts (48a, 48b) which are adjustable relative to one another to alter the separation between them so as to accommodate core regions (44) of different diameter. The collar (48) is formed from a plurality of laminates (1, 2, 3, 4, 5) having a second lamination axis (A) which is perpendicular to the first lamination axis (LA). (end of abstract)

Agent: Delphi Technologies, Inc. - Troy, MI, US
Inventors: Thomas W. Canepa-Anson, Anthony Thomas Harcombe
USPTO Applicaton #: #20060131448 - Class: 239533200 (USPTO)
Related Patent Categories: Fluid Sprinkling, Spraying, And Diffusing, Fluid Pressure Responsive Discharge Modifier* Or Flow Regulator*, Fuel Injector Or Burner

Actuator arrangement and fuel injector incorporating an actuator arrangement description/claims

The Patent Description & Claims data below is from USPTO Patent Application 20060131448, Actuator arrangement and fuel injector incorporating an actuator arrangement.

Brief Patent Description - Full Patent Description - Patent Application Claims

TECHNICAL FIELD

[0001] The present invention relates to an electromagnetic actuator arrangement. In particular, but not exclusively, the invention relates to an electromagnetic actuator arrangement for use in a fuel injector of an internal combustion engine. The invention also relates to a fuel injector incorporating an electromagnetic actuator arrangement.

BACKGROUND TO THE INVENTION

[0002] Referring to FIG. 1, it is known, for example from European Patent No EP 0987431 (Delphi Technologies Inc.), to provide a fuel injector 10 with two independently operable valve arrangements for controlling fluid pressure within the injector. The valve arrangements 12, 14 are arranged to control movement of a fuel injector valve needle 16 relative to a valve needle seating so as to control the delivery of fuel from the injector. Movement of the valve needle 16 away from the seating permits fuel to flow from an injector delivery chamber 17 through one or more outlet openings 18 of the injector into the engine or other combustion space. The injector delivery chamber 17 communicates with an injector supply passage 20 which, in turn, receives fuel from a high pressure pump chamber 23 forming part of the injector.

[0003] A first one of the valve arrangements is known as the control valve arrangement 12, or the nozzle control valve, and includes a control valve member which is movable between a first (open) position in which a communication path exists between an injector control chamber 22 at the back of the valve needle and a low pressure drain, and a second (closed) position in which the communication path is closed. The nozzle control valve is biased into the closed position by means of a spring. A second one of the valve arrangements takes the form of a spill or drain valve arrangement 14 which serves to control whether the pump chamber 23, and hence the fuel supply passage 20, communicates with the low pressure drain, or whether the communication path between the fuel supply passage 20 and the low pressure drain is closed. When the spill valve 14 is in a first (open) position the fuel supply passage 20 communicates with the low pressure drain and when the spill valve 14 is in the second (closed) position communication between the fuel supply passage 20 and the low pressure drain is closed. The spill valve is biased into the open position by means of the spring, which is shared with the nozzle control valve.

[0004] A surface associated with the valve needle 16 is exposed to fuel pressure within the control chamber 22 such that the pressure of fuel within the control chamber 22 applies a force to the valve needle 16 to urge the valve needle towards its seating, thereby closing the outlet openings 18. In this position, injection of fuel into the engine or other combustion space does not occur.

[0005] In order to commence injection, the nozzle control valve 12 is actuated such that the control valve member is moved into its open position, bringing the control chamber 22 into communication with a low pressure drain and causing fuel pressure within the control chamber 22 to be reduced. The force urging the valve needle 16 towards its seating is therefore reduced and, consequently, the valve needle 16 is caused to lift the valve needle 16 away from its seating due to the force of fuel pressure in the injector delivery chamber 17 to permit fuel to flow through the injector outlet openings 18.

[0006] In order to terminate injection, the nozzle control valve 12 may be de-actuated such that the control valve member is moved into its closed position, closing the connection between the control chamber 22 and the low pressure drain. The force acting on the valve needle 16 due to fuel pressure within the control chamber 22 is therefore increased, causing the valve needle 16 to be urged against its seating to terminate injection.

[0007] The nozzle control valve 12 thus operates to control the pressure differential between the fuel in the control chamber 22 and the fuel in the injector delivery chamber 17, that is to say the differential in the pressure acting to close the needle and the pressure serving to open it. In addition to the pressure of fuel in the control chamber 22 tending to urge the valve needle to close, a closing spring 21 is provided to assist the aforementioned closing force.

[0008] Another method of terminating injection is to use the spill valve arrangement 14. If the spill valve 14 is in the open position, fuel pressure within the fuel supply passage 20 (and hence the injector delivery chamber 17) is reduced so that the closing spring 21 urges the valve needle 16 against its seating, closing the outlet openings 18 in the injector body and terminating injection. If the spill valve 14 is in the closed position high pressure is re-established within the fuel supply passage 20 and the valve needle 16 is caused to lift against the spring force.

[0009] An actuator arrangement is provided to control both the nozzle control valve and the spill valve. The actuator includes first and second windings 24, 26 to which a current is supplied to control movement of first and second armatures, 28, 30 respectively. The first armature 28 is coupled to the nozzle control valve 12 so that energisation of the first winding 24 causes the first armature 28, and hence the nozzle control valve 12, to move between its closed and open positions. Energisation of the actuator causes the nozzle control valve 12 to move into the open position, whilst de-energisation of the actuator causes the nozzle control valve 12 to move into the closed position under the influence of the spring.

[0010] The second armature 30 is coupled to the spill valve 14 so that energisation of the second winding 26 causes the second armature 30, and hence the spill valve 14, to move between its open and closed positions. Energisation of the actuator causes the spill valve 14 to move into the closed position, whilst de-energisation of the actuator causes the spill valve 14 to move into the open position under the influence of the spring.

[0011] In other injector designs, the nozzle control valve 12 is not present so that only a spill valve 14 is provided. It is known in such arrangements to provide an electromagnetic actuator having a single winding to control operation of the spill valve.

[0012] In the injector shown in FIG. 1, each of the valves 12, 14 are controlled by means of a double pole actuator (i.e. the actuator arrangement takes the form of a twin, double pole actuator arrangement). In another known injector, such as that described in EP 1120563 A (Delphi Technologies, Inc.), two valves 12, 14 are provided but the nozzle control valve is controlled by means of a single pole actuator. The actuator part of an injector of this type is shown in FIG. 2. As in EP 0987431, the spill valve 14 is controlled by means of a double pole actuator. Like parts to those shown in FIG. 1 are identified with like reference numerals in FIG. 2.

[0013] It is desirable to reduce the eddy current effects that exist in the actuator cores of the injectors of the aforementioned type. There is also a requirement to improve the flux density capability. One way to achieve this is to provide the actuator with an inner core which is formed from a plurality of laminates, with a unitary outer pole of annular form receiving a part of the inner core. The winding of the actuator is received within the volume defined between the outer pole and the inner core. The combination of these features provides benefits for the magnetic performance of the actuator and also structural rigidity.

[0014] As the inner core is formed from a plurality of laminates, any deviation in the nominal thickness of the laminate sheet from which the layers are stamped will be compounded in the final core structure, resulting in a degree of ellipticity. This gives rise to manufacture and assembly problems, as not all nominally identical parts then fit conveniently with other parts of the actuator and/or actuator tooling parts. In particular, the winding bobbin by which the winding is wound onto the inner core requires a circular diameter inner core. It is an object of the present invention to address this problem.

SUMMARY OF THE INVENTION

[0015] According to a first aspect of the present invention, there is provided an actuator arrangement for use in a fuel injector of an internal combustion engine, the actuator arrangement including an inner core comprising a collar and a core region having a plurality of laminates stacked in the direction of (i.e. stacked along) a first lamination axis. A first outer pole receives at least a part of the core region, and an electromagnetic winding is received within a volume defined between the outer pole and the core region. The collar is formed from at least two collar parts which are adjustable relative to one another to alter the separation between them, thereby to accommodate core regions of different diameter.

[0016] Preferably, therefore, at least one of the laminates of the core region will be different in outer profile to its neighbouring laminate or laminates.

[0017] In a preferred embodiment, the collar is also formed from a plurality of laminates stacked in the direction of a second lamination axis which is perpendicular to the first lamination axis. Preferably, the first lamination axis is perpendicular to the actuator axis.

[0018] Lamination of the inner core of the actuator provides benefits for the magnetic performance of the actuator. It is particularly advantageous to laminate the core region of the actuator as this part is of reduced diameter, so the cross section viewed in the direction of eddy currents is relatively large. Thus, the invention enables eddy current effects to be reduced. Furthermore, as the collar is comprised of two parts which are movable relative to one another, it is readily compatible with core regions having different diameters. The diameter of the core region can vary if the thickness of its laminates differs from the nominal thickness, because in such circumstances it is necessary to adjust the layer profile to ensure the outer profile of the core region always has a circular outer periphery.

[0019] According to a second aspect of the invention, an actuator arrangement for use in a fuel injector of an internal combustion engine includes an inner core comprising a collar and a core region having a plurality of laminates stacked in the direction of a first lamination axis. A first outer pole receives at least a part of the core region, and an electromagnetic winding is received within a first volume defined between the first outer pole and the core region. The collar is formed from a plurality of laminates stacked in the direction of (i.e. stacked along) a second lamination axis which is perpendicular to the first lamination axis. In this aspect of the invention, the adjustability of the collar is only a preferred and/or optional feature.

[0020] In a preferred embodiment, the inner core comprises an upper core region (i.e. the afore-mentioned core region is an upper core region) which defines, together with the outer pole, the winding volume. In an injector application, the upper core region thus defines a pole of a double pole actuator for the spill valve of the injector.

[0021] Whereas lamination of the inner core of the actuator provides benefits for the magnetic performance of the actuator, the use of a unitary outer pole (for the upper core region in particular) provides structural rigidity. A combination of the two features is therefore particularly advantageous.

Brief Patent Description - Full Patent Description - Patent Application Claims
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Fuel injection valve
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