hybrid 1039 Report post Posted November 28, 2010 The task of the adaptive transmission control is to adapt gear selection to the driving characteristics of the driver as well as to the current driving situation. The main arguments for the use of adaptive transmission control are: •Reduction in fuel consumption in conjunction with steady driving characteristics •Avoidance of frequent gearshifts •Optimisation of driving safety on slippery roads •Reduction in amount of necessary driver interventions The control unit transfers the shift pulses for upshifts and downshifts to the transmission selector unit (solenoid valves, pressure regulator) and decides when the torque converter lockup clutch is to be engaged, taking factors such as comfort and safety into consideration. For this purpose, it processes, in a computer program, input variables such as engine speed, output speed, turbine speed, injection signal, throttle (accelerator pedal) position, kick-down switch, drive program, selector lever position and oil sump temperature. Note The control unit is installed in the E-box in the engine compartment. Driver type evaluation The influencing factors which are used to classify the type of driver are described in the following. The result of driver type evaluation has an effect on the selection of the gearshift program. Approach evaluation The behaviour when approach driving (forced or more moderate) influences the selection of the gearshift program. Kick-fast evaluation A sporty, performance-oriented gearshift program is selected automatically from a low gearshift, consumption-oriented driving program by quickly depressing the accelerator pedal (kick-fast). This normally results in a downshift. Driving evaluation When driving with a constant accelerator pedal position, a consumption-oriented gearshift program is selected within a short space of time and the transmission shifts into a higher gear. Kick-down evaluation The sporty gearshift program is selected immediately by "kick-down". On completion of kick-down, the gear selection is still influenced for a certain period of time in the sporty direction. Braking evaluation Above average braking manoeuvres cause the system to change to the sports gearshift program with earlier downshifts. Gearshift program selection In addition to driver type evaluation, there are still further factors for selecting one of the four gearshift programs. These programs are classified from very comfort and consumption-oriented through to very sporty. Program selection button This button makes it possible for the driver to intervene in the driving program manually. Selection of the S-program (sports) leads directly and exclusively to the sports gearshift program. This program is not exited before the A-program (adaptive) is selected and the adaptive functions are activated once again. The A-program is always selected when the vehicle is started. Uphill driving/trailer detection A performance-oriented gearshift program is selected when negotiating extreme gradients or when driving with above-average load. This avoids frequent upshifts and downshifts. Winter detection The winter gearshift program is selected if the drive wheels slip through even at low acceleration. The program starts off in 2nd gear and ensures earlier upshifts. This driving situation is evaluated by way of the sensors of the antilock brake system (ABS). Different wheel speeds at the front and rear axle result in winter detection. The winter program is exited automatically as soon as a road surface with good grip in conjunction with high drive torque is detected for several seconds. In addition to automatic gear selection in accordance with the above-specified criteria for gearshift program selection, four special functions are provided to ensure special driving situations are detected. Downhill detection Upshifts are suppressed when driving downhill without pressing the accelerator. If the driver presses the brake pedal, the transmission shifts down by one gear to provide extra assistance. This ensures the braking effect of the engine is utilised more effectively. Fast-off detection An upshift is prevented when the accelerator pedal is taken back rapidly. As a result the braking effect of the engine is utilised more effectively in these driving situations (fast changeover from accelerator pedal to brake pedal). This function considerably reduces the gearshift frequency when driving with a more sporty style. Stop-and-go detection In this driving situation there is no downshift into 1st gear. The car starts off automatically in 2nd gear. This increases driving comfort, reduces fuel consumption and reduces the crawling tendency when the car is stationary. By depressing the accelerator pedal more intensively, a downshift can be triggered in order to utilise the full power potential. AGS interfaces AGS inputs and more, http://spaghetticoder.org/bmw/wds/zinfo/246010001.htm Quote Share this post Link to post Share on other sites
