Processes for the operating or for the control of automatic vehicle gears are known already from the following publications:
(1) DE 19 32 966 C3 PA1 (2) DE 32 05 767 C2 PA1 (3) EP 0 176 750 B2 PA1 (4) EP 0 435 372 B1 PA1 (5) DE 30 25 054 A1
It is a known practice in automatic vehicle gears to adjust the pressure of the working medium, which serves for the actuation of the friction elements of the gear, in dependence on various operating parameters of the motor vehicle. In the process disclosed in DE 19 32 966 C3, the pressure adjustment occurs via an electronic control over predetermined pressure characteristic curves. A compensation for parameter changes in consequence of series scatterings or aging effects cannot thereby be achieved. Friction values of lamellae, characteristic curves of pressure regulators or springs as well as the moment given off by the motor, however, are constantly subject to these scatterings, whereby, on the one hand, shift quality fluctuations are evoked, but, on the other hand, high demands are placed on the tolerances of the parts used or employed. This works out very unfavorably in respect to costs.
In the mode of execution disclosed in DE 32 05 767 C2, therefore, closed regulating circuits were used. These have the disadvantage, however, that a regulating magnitude taking the necessary dynamics into account is required. Basically, in the regulating stretch motor-to-gear, in consequence of the down times present, stability problems are to be expected in the entire operating line, and for this reason clear regulating deviations have to be accepted into the bargain before the regulation can engage with correcting effect, which results in a poor shifting comfort.
From DE 30 25 054 A1 there is known a pressure regulator for an automatic gear control for vehicles, in which for the gear shifting in dependence on the load, a desired shifting time is set. The actually occurring shifting time is measured and compared with the stored desired shafting time. If deviations arise here, a correction value is deposited in a correction register which, in a shifting of gears, is added to the pressure characteristic curves which are deposited originally in a storage and serve the purpose of controlling the pressure during the gear change.
In a process for the electronic control of an automatic vehicle gear such as is described in EP 0 176 750 B2, correction values are calculated and deposited in dependence on the load and turning rate, so that there can occur an exact adaptation to different load/turning rate ratios. The desired and the actual values for the characterizing magnitude as well as the correction values formed are deposited in load turning rate fields, in which the actual values are formed by mean-value formation of individual values from several shifting processes, so that until the conclusion of the mean-value formation the previous correction value remains preserved and after execution of the correction the actual values are set to the desired values for the mean-value formation, by alteration of the correction value.
In EP 0 435 372 B1 there is described a process for the control of the change, in an automatic gear of a vehicle, from a reduced-torque transmitting fluid-pressure driven torque transmission device, which is allocated to a lower speed ratio, to a fluid- pressure torque transmission arrangement, which is allocated to an increasing torque-transmitting fluid pressure driven torque transmission arrangement which is assigned to a higher speed ratio when the motor choke is substantially closed. The off-going torque transfer device there is brought out of engagement simultaneously or substantially simultaneously with the engagement of the up-coming torque transfer device. The gear has an input, an output and a turbine which is coupled over the input with the drive machine. The process described in this publication comprises the steps mentioned in the following.
The filling pressure is applied to the up-coming torque transmission device for a filling time, in order substantially to fill the upcoming torque transmission device with operating fluid. The turbine speed increase is detected by reason of an initial slippage of the torque transfer device transmitting less torque, a synchronization of the upcoming torque transmission device on the basis of the turbine speed and the starting speed is established, and the change is completed when a synchronization is proved. There, on the off-going torque transmitting device for a time span shorter than the filling time, a lower pressure is applied and then the off-going torque transfer arrangement is emptied of operating fluid. If a turbine speed increase is detected, there takes place a run-through of a control loop. In this run-through a slippage profile is set up, which represents the desired slippage during the run-through. The slippage of the upcoming torque transfer device is measured and controlled, in order to control the slippage of the upcoming torque transfer device on the basis of the slippage speed profile.
In all these forms of executions for the influencing of the shifting courses, especially of the shifting times, by influencing the control pressure for action, for example, on the lamellae, it is known to adapt this pressure adaptively to the concrete circumstances and to adjust it. In automatic gears, despite influencing the control or regulating pressure in dependence on the ascertained travelling characteristic values, in respect to the quality only partially satisfactory shifting results are achieved, which arise sporadically in shiftings.