Patent Grant
8244440
This application is a national stage completion of PCT/EP2007/051677 filed Feb. 21, 2007, which claims priority from German Application Serial No. 10 2006 011 805.7 filed Mar. 15, 2006.
The invention concerns a process and a device for actuating a shifting arrangement with electric actuators.
Electrically operable actuators, for example valves, are used in motor vehicles, in particular, for control functions in hydraulic circuits. There are basically two different types of designs. In the commonly utilized pilot operated valves, a magnet in a pilot operated system acts on a relief bore, which equalizes the pressure difference between the pressurized sides of a sealing element, wherein the sealing element on the valve seat is activated by the pressure medium itself. Magnetic valves of this kind have the advantage that they can control large flow volumes at high pressures with relatively low force and accordingly low current consumption. However, since they work according to the differential pressure principle, they require a constant specific minimum operating pressure.
Directly controlled valves do not require a minimum operating or differential pressure for their switching function so their operating range starts at zero bar and reaches a specific maximum operating pressure. This type of valve can have a particularly compact configuration, is suitable for practically any kind of installation position and is comparatively cost effective. In magnetic valves of this kind, the magnetic force is utilized directly to open or close the valve seat. The valve seat is generally closed by way of a spring force and the static pressure of the medium when it is disconnected. If the magnet or the magnetic coil is supplied with electric voltage, an armature is lifted against these forces from the valve seat and the valve is opened. Here the maximum operating pressure and the volume flow depend directly on the magnetic force. For this reason directly controlled valves consume, as a rule, more current than pilot operated valves. This can have as a consequence an unallowably high current load during operation in electric circuits with limited current supply.
From DE 199 04 902 A1 is known a proportional pressure control valve for actuating a clutch in an automatic motor vehicle transmission, which is configured as a directly controlled valve. The directly controlled valve has a proportional magnet, which is connected via an armature rod to a piston. The piston is pressed by a spring force into an initial position against a valve seat, whereby the valve is closed. The magnetic armature, and with it the armature rod with the piston, is moved against the spring force by a suitable current supply to the coil of the magnet, whereby the piston lifts from the valve seat and an inlet opening for the medium (hydraulic oil) is opened. When the inlet is fully open, the magnetic armature is seated on a spacer disk in a holding position and is held in this position via a corresponding current feed. This holding function can be adjusted via the coil current with allowance for the hydraulic pressure that acts against the piston, and can be used to control the pressure on a clutch cylinder.
Further, from DE 100 03 896 A1 a process is known for actuating proportional magnets in directly controlled valve design in the manner described in DE 199 04 902 A1, or in a pilot operated valve design, as can be seen in DE 199 04 901 A1, in which a holding position is realized. Means that detect the movements of the armature based on induced voltages with feedback effects on the coil current are provided therein. These feedback effects are in direct connection with the holding function and can be utilized to guide a controlled transition between a holding range (pressure range within the holding position) and a control range (pressure range outside of the holding position) of the valve.
Finally, a control arrangement is known from DE 195 36 697 A1 which controls the actuating current of a proportional directional valve in a hydraulic control section. The control arrangement is based on non-linearities in the hydraulic section, which cannot be sufficiently detected with conventional state monitors, and utilizes digitally detected sensor values from which estimated signals can be determined by an iteration process in a number of integration steps, which are then made available to the control arrangement for further processing. The process is also suitable for systems with pilot operated valves as well as for systems with directly controlled valves. In directly controlled valves a measured variable derived from the measured coil current can be used as an input variable for the control circuit.
A disadvantage of the known processes and devices for actuating proportional magnets is that, even though they control the actuation of individual proportional magnets, the proportional magnets are only viewed in isolation. The effects, which the relatively high current demand especially of directly controlled valves, can have in the shifting arrangement with a multitude of different consumers are for the most part not taken into consideration. This can impair the reliability of the affected system in a shifting arrangement with a limited total available current, as is common in motor vehicle electric circuits.
Considering this background, it is an object of the invention to disclose a method and a device for actuating a shifting arrangement, which reliably prevent a preset allowed current load, with a comparatively high current requirement of electric actuators or consumers, for example, directly controlled valves, from being exceeded.
The invention is based on the realization that exceeding an allowed current load in the shifting arrangement can be prevented with the aid of a monitoring function, which processes the shift requests after a test or sequentially.
The invention is accordingly based on a process for actuating a shifting arrangement with electric actuators with directly controlled valves of an electrohydraulic, electropneumatic, electromagnetic or electromotor transmission control of a motor vehicle. In order to attain the object, the invention provides that a current monitoring function for limiting a current load in the shifting arrangement is present which comprises at least the following steps:
The current monitoring function, according to the invention, makes it advantageously possible to use directly controlled valves with an increased current requirement in an electrohydraulic transmission control and ensures at the same time that a maximum current load of the transmission control is maintained. This is achieved by detecting the shift requests and subjecting these to a priority test. If there is danger of exceeding a previously determined total available current, positively tested shift requests are executed based on their priority. Conversely, negatively tested shift requests are initially blocked until their processing is possible and are then executed.
This process can basically be used arbitrarily on any corresponding circuits, wherein the respective current limits can be freely applied. This produces very flexible application possibilities. Direct control magnetic valves can be used in this way as actuators, in particular in motor vehicles, in order to convert the signals processed in a transmission control device to initiate a gear change into an actuation of the corresponding shift valves to operate at least one clutch.
Here it is advantageous to prioritize the requested valve feeds depending on their respective function as a shift element, possibly in an active shift phase, and on the type of shift request, wherein with respect to the type of shift request, a distinction can be made at least between the functions of engagement, change, and confirmation, since different current loads occur therein. The result is that preferential safety-relevant valve operations are always carried out immediately and, at the same time, an effective sequence of shifting procedures is ensured.
It can additionally be provided that the total available current is determined based on a total effective current, preset limit currents, and predetermined reserved currents for shift elements that are still to be engaged, wherein it can be provided in addition that the effective total current is determined based on a permanent current load of the shifting arrangement and an effective current requirement of the active shift elements, and that a distinction is made, with regard to the limit currents, between long-term current loads and short-term current loads.
By taking into consideration permanent, instantaneous and expected current loads, an effective limit value for the actual total current available under the respective operating conditions is obtained, which allows effective utilization of the current potential so that deferred shifting procedures are only delayed for as long as is absolutely necessary.
In order to determine the effective current requirement of the active shift elements as well as the limit currents for long-term and/or short-term current loads, it is advantageous to make use of the characteristics of the respective electric fuses, which are generally present in any case. These data are retrievable at any time as benchmark data to determine the total available current.
An even more accurate determination of the total available current can be achieved in that, as can also be provided, the current requirement of the active shift elements and/or the limit currents for long-term and/or short-term current is obtained using a learning algorithm, which can be or is derived from previous actuations.
It is also possible to determine a maximum allowed long-term current and a short-term maximum available current from the determined total available current. Because it is usually harmless to allow short-term overloads at the corresponding fuses of electric consumers, it is advantageous not to block short-term shifting procedures that exceed the permanent current load. It is practical for this purpose to take into consideration an expected duration of a respective actuation when the shifting requests are tested.
It is another object of the invention to create a device for actuating a shifting arrangement, which reliably prevents the preset allowed current load from being exceeded when there is a comparatively high current requirement of the electric actuators or consumers, for example, directly controlled valves.
Further, the invention is therefore based on a device for actuating a shifting arrangement with electric actuators, for example, having directly controlled valves of an electrohydraulic, electropneumatic, electromagnetic, or electromotor transmission control of a motor vehicle. The invention also attains the object by providing control and detection means, such that a current monitoring function can be generated in order to limit the current flow in the shifting arrangement.
It can also be provided that the control and detection means feature at least one processor unit, in which instantaneous, permanent and expected electric current flows can be detected and further processed in a time-resolved manner, in which shift requests can be detected and can be further processed in a priority test in a time-resolved manner, in which the processed current flows can be compared with the processed shift requests and through which output signals for initiating current-limiting measures in the shifting arrangement can be generated based on the processed current flows.
With this arrangement, it can be advantageously achieved that consumers with high current consumption, for example directly controlled valves, can be utilized in transmission controls, wherein the danger of exceeding a preset maximum current load is simultaneously prevented.
The invention will now be described, by way of example, with reference to the accompanying drawings in which:
A simplified block diagram of an electronic transmission control of a motor vehicle is accordingly shown in
The transmission control unit 1 also has a processor unit 3 in which electric current and voltage data can be detected and processed in a time-resolved manner by way of suitable software, whereby a current monitoring function is made available. Via output data of the transmission control unit 1, the shift elements of the hydraulic circuit 5 can be actuated which, in turn, control a transmission and/or clutch arrangement 4.
In an electronic transmission control, a driver request is converted into signals, for example, for gear selection, converter lockup or clutch operation, by way of a gear selector I position, a driving program switch, a kickdown switch and/or throttle flap position in the transmission control unit 1. The associated control valves in the hydraulic circuit 5, which operate the corresponding shift valves, are actuated for this reason.
Below a process for actuating a shifting arrangement with directly controlled valves of a motor vehicle electrohydraulic transmission control, such as this will be explained with reference to the current diagram shown in
Here “permanent current loads,” for example, the permanent supply of an electronic control unit, are detected first and the instantaneous “current of active elements” is determined based on their fuse. From this, a total effective current is obtained. “Reserved currents” for the elements to be subsequently shifted are added to it during further processing. A fixed “consumer current” is calculated therefrom.
Subsequently the limits currents I_max_fuse_short for short-term and I_max_fuse_long for long-term loads on the corresponding fuses are determined on the basis of the fuse specifications and the previous actuation. The differences between the “consumer current” and the limit currents make the “current available for further consumers” for short-term or long-term loads. From the limit currents and the total effective current, as well as the reserved currents, the total available current of the system for short-term or long-term loads is obtained.
Based on this determined total available current, all shift requests present at a point in time are tested regarding the available electric currents, the duration of actuation to be expected and preset priorities. The requested valve feeds are classified, according to the type and function of the respective shift element in the hydraulic circuit, according to the instantaneous shift phase and according to the types of shift requests, for example, gear change, possibly with counter-pulse, engagement, or confirmation.
Subsequently, the valve feeds determined to have priority are immediately connected and other possible current feeds are not connected until it is possible, that is, only when the maximum available current is not exceeded thereby.
If the test shows that the total available current is sufficient for all currently available shift requests, all of the shift requests can, of course, be processed without time limitations.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 011 805 | Mar 2006 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2007/051677 | 2/21/2007 | WO | 00 | 9/25/2008 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2007/104630 | 9/20/2007 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4724502 | Kawahira et al. | Feb 1988 | A |
| 5370320 | Sofer | Dec 1994 | A |
| 5465757 | Peters | Nov 1995 | A |
| 5730509 | Eith et al. | Mar 1998 | A |
| 5742467 | Schmitz | Apr 1998 | A |
| 5749349 | Detweiler et al. | May 1998 | A |
| 5749350 | Bender | May 1998 | A |
| 5810330 | Eith et al. | Sep 1998 | A |
| 5829335 | Ewald et al. | Nov 1998 | A |
| 5832777 | Weilant | Nov 1998 | A |
| 5992590 | Harries | Nov 1999 | A |
| 5993354 | Winks | Nov 1999 | A |
| 6209408 | DeJonge et al. | Apr 2001 | B1 |
| 6301528 | Bertram et al. | Oct 2001 | B1 |
| 6504699 | Rader et al. | Jan 2003 | B1 |
| 6532980 | Langeveld | Mar 2003 | B1 |
| 6591704 | Kamiya et al. | Jul 2003 | B2 |
| 6592493 | Loeffler et al. | Jul 2003 | B2 |
| 6607176 | Mayr et al. | Aug 2003 | B1 |
| 6619615 | Mayr et al. | Sep 2003 | B1 |
| 6657846 | Philipp et al. | Dec 2003 | B1 |
| 6694803 | Klik et al. | Feb 2004 | B2 |
| 6705175 | Klatt | Mar 2004 | B1 |
| 6815625 | Leopold et al. | Nov 2004 | B1 |
| 6891710 | Mayr et al. | May 2005 | B2 |
| 6897710 | Pasotti et al. | May 2005 | B2 |
| 7011379 | Rader et al. | Mar 2006 | B2 |
| 7021603 | Wygnaski | Apr 2006 | B2 |
| 7252619 | Tabata et al. | Aug 2007 | B2 |
| 7430936 | Petzold et al. | Oct 2008 | B2 |
| 7878084 | Petzold et al. | Feb 2011 | B2 |
| 20030173825 | Rader et al. | Sep 2003 | A1 |
| 20080197698 | Gehring et al. | Aug 2008 | A1 |
| 20090093935 | Ingenbleek et al. | Apr 2009 | A1 |
| Number | Date | Country |
|---|---|---|
| 195 36 697 | Apr 1997 | DE |
| 198 57 916 | Jun 2000 | DE |
| 199 04 901 | Aug 2000 | DE |
| 199 04 902 | Aug 2000 | DE |
| 100 03 896 | Aug 2001 | DE |
| 10341907 | Sep 2003 | DE |
| 1375979 | Jan 2004 | EP |
| 1 626 322 | Feb 2006 | EP |
| WO-02087053 | Oct 2002 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20090093935 A1 | Apr 2009 | US |
