Automatic transmission shift point control system and method of use
An automatic transmission control system for controlling gear shifting in an automatic transmission in a motor vehicle having an automatic transmission in a motor vehicle in operative communication with a transmission control unit, the transmission control unit has adaptive gearshift logic that operates to compensate for variations in vehicle conditions and road conditions, wherein the transmission control unit outputs at least one gearshift command to the transmission to control shifting of gears in accordance with the adaptive gearshift logic. A control method uses the adaptive gearshift logic to control gear shifting within the transmission in accordance with adaptive gearshift points that compensate for variations in vehicle conditions and road conditions.
1. Method for controlling gear shifting in a fixed input-output multi-ratio automatic transmission coupled to an engine in a motor vehicle, comprising:
providing a first gearshift map for controlling gear shifting in the fixed input-output multi-ratio automatic transmission, wherein the first gearshift map comprises a plurality of first gearshift points;
providing a second gearshift map for controlling gear shifting in the fixed input-output multi-ratio automatic transmission, wherein the second gearshift map comprises a plurality of second gearshift points;
monitoring acceleration of the motor vehicle;
determining an acceleration deviation from a nominal vehicle acceleration;
determining a gearshift point modifier value corresponding to the acceleration deviation;
generating a third gearshift map for controlling gear shifting in the fixed input-output multi-ratio automatic transmission based upon the gearshift point modifier value, the first gearshift map, and the second gearshift map, wherein the third gearshift map comprises a plurality of third gearshift points calculated from corresponding first and second gear shift points and the gearshift point modifier value; and
wherein each calculated third gearshift point has a value between and including the corresponding first and second gearshift points.
2. The method of claim 1 , further comprising:
determining a first up-shift point from a current gear position based upon the first gearshift map;
determining a second up-shift point from the current gear position based upon the second gearshift map; and,
generating an adaptive up-shift point from the current gear position based upon the first and second up-shift points and the gearshift point modifier value.
3. The method of claim 1 , further comprising:
determining a first down-shift point from a current gear position based upon the first gearshift map;
determining a second down-shift point from the current gear position based upon the second gearshift map; and,
generating an adaptive down-shift point from the current gear position based upon the first and second down-shift points and the gearshift point modifier value.
4. The method of claim 1 , further comprising providing the first gearshift map for controlling gear shifting in the fixed input-output multi-ratio automatic transmission corresponding to a plurality of shift points at which the engine operates most efficiently.
5. The method of claim 4 , further comprising providing the second gearshift map for controlling gear shifting in the fixed input-output multi-ratio automatic transmission corresponding to a plurality of shift points at which the engine operates at a maximum power condition.
6. The method of claim 1 , further comprising generating the third gearshift map for controlling gear shifting in the fixed input-output multi-ratio automatic transmission based upon the gearshift point modifier value, the first gearshift map, and the second gearshift map during a sampling time during ongoing operation of the vehicle.