Slip at vehicle transmission system with hydrokinetic converter in the urban test cycle

The study concentrated on slip phenomenon occurring at hydrokinetic converter in passenger car transmission system. Optimization of modern automatic transmission systems aims, on the one hand, to further increase the comfort of use, and on the other hand to improve the efficiency and reliability operation of individual components, in such a way as to ultimately result in lowering fuel consumption and also harmful emissions. One of the important factors affecting the mentioned transmissions properties as a whole system is the slip phenomenon occurring between the pump and the hydrokinetic converter turbine. The study presents the results of research on ZF 4HP20 and Fuji Hyper M6 gearboxes operating in vehicle transmission systems. The tests were carried out using the MAHA MSR 500 chassis dynamometer during driving at chosen test cycles. The research covered the transmission systems operating according to selected control algorithms affecting not only the gear shifting strategy but also the operation of the lock up clutch causing the transmissions slip values. As shown by the conducted research, the algorithm controlling the operation of the torque converter can have a significant influence on their operating indexes. The conducted analyses indicate the possibilities of improving the transmission operating indexes, especially in urban driving cycles.