Electricity: electrical systems and devices – Control circuits for electromagnetic devices – For relays or solenoids
Reexamination Certificate
2000-03-29
2001-09-18
Leja, Ronald W. (Department: 2836)
Electricity: electrical systems and devices
Control circuits for electromagnetic devices
For relays or solenoids
C361S206000
Reexamination Certificate
active
06292345
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a method for controlling an electromechanical actuator, in particular, to an actuator for controlling an internal combustion engine.
An actuator is described in German Published, Non-Prosecuted Patent Application 195 26 683A1 corresponding to U.S. Pat. No. 5,691,680 to Schrey et al. The actuator has an actuating element in the form of an inlet and/or outlet valve, and an actuating drive. The actuating drive has two electromagnets between which, and, in each case against the force of a resetter, an armature plate can be moved by switching off the coil current to the holding electromagnet and switching on the coil current to the capturing electromagnet. The coil current to the respective capturing electromagnet is kept constant at a predetermined capture value I_MAX for a predetermined time period, is then switched off for a predetermined switched-off time, and is then regulated at a holding value by a two-point regulator with hysteresis. The time response of the coil current during the switched-off time is used to identify bouncing of the armature plate against the respective electromagnet, and to correct the capture value appropriately. However, the coil current cannot be set to the corrected capture value until the next capture process. Thus, the armature plate may move so far away from the capturing electromagnet during the switched-off time that the holding current can no longer apply sufficient force to move the armature plate into contact with the capturing electromagnet.
Another actuator is described in U.S. Pat. No. 5,650,909 to Remele et al. The actuator has an actuating element in the form of an injection valve, and an actuating drive. The actuating drive has an electromagnet, an armature, and a resetter. When current flows through a coil of the electromagnet, the armature plate can be moved against the force of the resetter into contact with the electromagnet. The actuating drive has an associated regulator, whose controlled variable is the current through the coil of the electromagnet. In order to move the armature from a first position to make contact with the electromagnet, a maximum value is predetermined as a set value of the current through the coil until the armature starts to move. An opening value is then predetermined as the set value, which is less than the maximum value. When the armature is in contact with the electromagnet, a holding value is predetermined as the set value, which is less than the opening value. Choosing the opening value to be low, as is advantageous in order to keep the power consumption low, may lead to the armature plate dropping and not coming into contact with the electromagnet.
European published, non-prosecuted patent application no. EP 07 24 067 A1, corresponding to U.S. Pat. No. 5,752,478 to Sono et al. and U.S. Pat. No. 5,765,514 to Sono et al., discloses another actuator having an actuating element in the form of an inlet and/or outlet valve. A position sensor is provided to detect the position of the inlet and/or outlet valve.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method for controlling an electromechanical actuator that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that is simple and ensures capture of the armature plate.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a method for controlling an electromechanical actuator, including providing an actuator having an actuating element and an actuating drive, the actuating drive having at least one electromagnet with a coil, a movable armature plate, a regulator having current through the coil as a controlled variable, and at least one resetter prestressing the armature plate into a predetermined rest position with the actuating drive, predetermining a first capture value as a set value of the current through the coil, defining a holding value, predetermining a second capture value as a set value when a predetermined first condition is satisfied, the second capture value being greater than the holding value, and predetermining the holding value as a set value when a predetermined second condition is satisfied.
The solution of the invention has the advantage that the capture value can be predetermined to produce a desired speed profile for the armature plate, and such that the second capture value can be set to ensure reliable capture of the armature, thus preventing the armature from dropping into a rest position.
In accordance with another mode of the invention, a position sensor is provided for determining a position of the armature plate and the predetermined first condition is satisfied when a magnitude of the position of the armature plate exceeds a predetermined threshold value.
In accordance with a further mode of the invention, the second capture value is a function of a speed of the armature plate before the predetermined threshold value was exceeded.
In one preferred refinement of the invention, the second capture value depends on the speed of the armature plate before the threshold value is exceeded. The dependency has the advantage that the second capture value can be predetermined, on one hand, to achieve low heat losses and, on the other hand, to reliably capture the armature plate.
In accordance with an added mode of the invention, the second capture value is defined to be greater than the first capture value.
In accordance with an additional mode of the invention, the predetermined first condition is satisfied when the magnitude of the position of the armature plate exceeds a further threshold value that is longer than a predetermined time period, and a magnitude of the further threshold value is defined to be less than a magnitude of the predetermined threshold value.
In a further advantageous refinement of the invention, the second capture value is predetermined as a set value when the position of the armature plate exceeds a further threshold value whose magnitude is less than the threshold value K0, K5, for longer than a predetermined further time period. The predetermining ensures that the armature plate is reliably captured when the force caused by the first capture value is not sufficient for the position of the armature plate to exceed the threshold value K0, K5.
In accordance with yet another mode of the invention, the second condition is satisfied when a further time period is predetermined as a set value for the second capture value.
In accordance with yet a further mode of the invention, the further time period is a function of a speed of the armature plate before the predetermined threshold value was exceeded.
In accordance with a concomitant mode of the invention, the first capture value is corrected as a function of a speed of the armature plate before the predetermined threshold value was exceeded.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method for controlling an electromechanical actuator, it is nevertheless not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
REFERENCES:
patent: 4029068 (1977-06-01), Jones et al.
patent: 5650909 (1997-07-01), Remele et al.
patent: 5818680 (1998-10-01), Schmitz et al.
patent: 195 18 056 A1 (1996-11-01), None
patent: 195 26 683 A1 (1997-01-01), None
patent: 196 05 974 A1 (1997-08-01), None
patent: 0 376 716 (1990-07-01), None
patent: 0 566 281 A1 (1993-10-01), None
patent: 0 662 697 A1 (1995-07-0
Koch Achim
Muller Nikolaus
Greenberg Laurence A.
Leja Ronald W.
Lerner Herbert L.
Siemens Aktiengesellschaft
Stemer Werner H.
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