Adaptive transmission control: Notes

In the same way as the automatic transmissions used to date, this 6-speed-automatic transmission also offers a choice between a comfort program and sport program.

The adaptive transmission control (component of the electronic transmission control) adapts the shift characteristics of the comfort program and sport program to the driver's demand and the driving situation.

In each of the two programs, the adaptive transmission control switches on request from a basic characteristic map into a performance-oriented characteristic map:

• Comfort program at selector-lever position "D"

  The comfort program is based on various characteristic maps: e.g. the characteristic map "XE" (extreme economy) and the characteristic map "E" (economy). The EGS control module normally chooses the economical characteristic map "XE" (= basic characteristic map). With special requirements (e.g. load requirement), a switch is made to the performance-oriented characteristic map "E". If the input signals change towards "more moderate driving style", there is a switch back to the economical characteristic map "XE".

• Sport program at selector-lever position "M/S"

  The Sport program implements dynamic sports shift characteristics. In the sport program, there are various characteristic maps, e.g. the basic characteristic map "S" (sport) and the performance-oriented characteristic map "XS" (extreme sport). With a very dynamic driving style, there is a switch from the basic characteristic map "S" to the performance-oriented characteristic map "XS".

The adaptive transmission control takes account of the following requirements:

Adaptation to the driver type 

The adaptation to the driver type runs via the following values:

• Kick fast

  When the accelerator pedal is pressed down quickly, the shift program is changed accordingly. Here, the determined accelerator-pedal value is compared with threshold values in the EGS control module. The result of this comparison is that one of the two possible programs is proposed (e.g. with comfort program "XE" or "E", with sport program "S" or "XS").

• Cornering detection

  The cornering detection reacts to the lateral acceleration of the vehicle with an indirect adaptation to the driver type.

  The lateral acceleration is regarded as an indirect statement on the preferred dynamism and does not lead to an immediate gearshift reaction (gearshifts in bends can negatively influence driving stability).

  The lateral acceleration is calculated from the signals of the wheel-speed sensors as well as the yaw rate and driving speed.

• Brake assessment

  The brake assessment is similar to the process for assessment of "kick fast".

  The braking deceleration is determined and compared with threshold values in the EGS control module. The result of this comparison is that one of the two possible programs is proposed (e.g. with comfort program "XE" or "E", with sport program "S" or "XS").

The adaptation to the driver type is restarted every time the vehicle drives off from a standstill.