Driving force control system for a vehicle

A transmission control system for a vehicle having an engine with an output shaft, a torque converter connected to said output shaft of the engine and having an output shaft, a stepped automatic transmission mechanism connected to said output shaft of the torque converter, said stepped automatic transmission mechanism having an output shaft and a clutch for engaging and disengaging a plurality of gear shafts and input/output shafts to change a shift change ratio according to different changing modes, each of said changing modes comprising a chance between a particular pair of shift chance ratios, and a driving axle connected to said output shaft of the stepped automatic transmission mechanism, comprising:

• shift signal output means for delivering a shift signal which indicates a shift change ratio of said stepped automatic transmission mechanism;
• input torque detecting means for detecting an input torque of said stepped automatic transmission mechanism;
• shift start recognition means for recognizing an actual mechanical shift start timing of said stepped automatic transmission mechanism;
• engaging pressure control means for changing an engaging pressure of said clutch in accordance with a manipulation variable inputted thereto;
• input torque-manipulation variable relationship storing means for storing, for every changing mode of said shift change ratios, an input torque-manipulation variable relationship between said input torque and said manipulation variable for a shift change ratio indicated by every shift signal;
• and
• manipulation variable calculation means operative when said shift signal from said shift signal output means changes and said actual mechanical shift start timing is recognized by said shift start recognition means, for calculating a manipulation variable under shifting corresponding to said input torque during a period from when said shift signal changes until said shift start timing, by utilizing said input torque-manipulation variable relationship corresponding to a changing mode of the shift change ratio indicated by the shift signal, so as to deliver the manipulation variable under shifting to said engaging pressure control means.