Method of determining initial transmission calibration
View Patent ↗A process for learning the pressure and volume characteristics for a given torque-transmitting mechanism is established on the final assembly line wherein a powertrain incorporating the desired transmission learning is installed within a vehicle. During the test process, the vehicle speed is generally maintained at Idle and the vehicle shift mechanism is maintained in Park, thereby mechanically locking the transmission output shaft. The torque-transmitting mechanisms to be learned are then engaged and disengaged in a predetermined sequence and the volume of the torque-transmitting mechanisms and the pressure characteristics of the controlling solenoid are learned.
1. A method of determining an initial transmission calibration of at least two torque-transmitting mechanisms installed in a vehicle on an assembly line' said method comprising the steps of:
determining if the vehicle is on the assembly line with the engine at Idle and the transmission in Neutral or Park;
fully engaging a first of the torque-transmitting mechanisms;
beginning engagement of a second of the torque-transmitting mechanisms to determine a fill-time and apply chamber volume for the second torque-transmitting mechanism by monitoring a speed of a torque converter turbine in said transmission;
recording the fill-time and volume;
determining the pressure characteristic for the second torque-transmitting mechanism by fully applying both of said torque-transmitting mechanisms, reducing the pressure at the second torque-transmitting mechanism until a first predetermined slip speed occurs at the torque converter, recording the pressure, further reducing the pressure at the second torque-transmitting mechanism until a second predetermined slip speed occurs at the torque converter, recording the pressure; and
placing the recorded time, volume, and pressures in the directive cells in the transmission.
2. The method of determining an initial transmission calibration of at least two torque-transmitting mechanisms installed in a vehicle on an assembly line defined in claim 1 , said method further comprising the steps of:
repeating the process with the second torque-transmitting mechanism fully engaged and controlling the first torque-transmitting mechanism to learn the characteristics thereof.
3. The method of determining an initial transmission calibration of at least two torque-transmitting mechanisms installed in a vehicle on an assembly line defined in claim 1 , said method further comprising the steps of:
placing a transmission control in Park;
fully engaging and disengaging a third torque-transmitting mechanism for a plurality of cycles;
fully engaging said second torque-transmitting mechanism;
determining the fill-time and volume of the third torque-transmitting mechanism;
determining the pressure characteristics of the third torque-transmitting mechanism.