IAV has developed a strategy for transmission ratio selection that serves AMT, ATs, CVTs and Hybrid drivetrains.
Since the power demand dependent strategy is applicable to all transmission types, it is possible to implement the same character of vehicle behavior. As a result, a manufacturer specific vehicle characteristic can be given to the complete range of powertrains.
This universal field of application is made possible by the choice of ratio being dependent on the drivers demand of traction power instead of the usual dependency concerning the accelerator position and the vehicle velocity. Therefore, as opposed to conventional shifting strategies, the selected transmission ratio guarantees the demanded traction power. In the case of insufficient power at the actual transmission ratio, the engine speed will be increased. The power dependent strategy makes a direct conversion of the demanded power into a target engine speed possible, which is essential for a transmission ratio strategy in CVTs. An additional ratio logic controls the course of engine speed so that it coincides with the drivers expectations.
This paper presents the basic concept of IAV's power optimized transmission ratio strategy GALOP. A survey of the signal flow is given to make the principle of operation and the possibilities for interaction with additional functions transparent. Finally, results of a feed-forward MATLAB/ SIMULINK simulation demonstrate the quality of the concept and the potential of optimized gearshift decisions compared to conventional shifting strategies.