Pressure Modulation

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To provide a high level of shift comfort and durability, the hydraulic pressure in the shift related friction elements of the transmission must be matched very accurately to the transmission input torque. This hydraulic pressure is composed of a hydraulically pre-set basic pressure and a controlling pressure that is set by one of the electro-hydraulic pressure regulators.

The transmission input torque can be directly calculated from the following operating parameters: engine torque signals, engine speed or any signals transmitted from the ECM by CAN, and converter slip. Separate pressure characteristics for each gear change make it possible to adapt precisely to the particular shift operation. A further improvement in shift comfort is achieved by individual treatment of special cases, such as manual shifts.