System and method for controlling an automatic transmission

A system for controlling an automatic transmission of a vehicle, the vehicle including an internal combustion engine operatively coupled to the automatic transmission, an axle operatively coupled to the automatic transmission, and an electric motor-generator, the automatic transmission including a plurality of clutches, the system comprising:

• a pressure source;
• a plurality of valves, each valve being in fluid communication with the pressure source and at least one of the clutches;
• and
• a controller in electronic communication with the pressure source and the plurality of valves, the controller being configured to:
• determine an initial gear ratio of the automatic transmission based on a gear shift map while the vehicle is solely driven by the electric motor-generator;
• identify potential clutches of the plurality of clutches based on the initial gear ratio, each of the potential clutches being configured to shift between a disengaged state and an engaged state, each of the potential clutches having a fill time;
• determine a temperature of the transmission fluid;
• determine which of the potential clutches has a largest fill time based at least in part on the temperature of the transmission fluid in order to identify at least one of a plurality of target clutches;
• determine a target gear ratio of the automatic transmission based on the at least one identified target clutch;
• and
• send an activation command to the pressure source to turn on the pressure source;
• and
• before the internal combustion engine is started, send pressure commands to the valves that are in fluid communication with the potential clutches used to select the target gear ratio in order to transfer sufficient transmission fluid to the at least one target clutch to reach a pressure threshold in the target clutches in order to minimize a time necessary to transfer torque from the internal combustion engine to the axle through the automatic transmission once the internal combustion engine is started.

A vehicle, comprising:

• an automatic transmission including a plurality of clutches, each of the clutches being configured to shift between a disengaged state and an engaged state, each of the clutches having a fill time;
• an internal combustion engine operatively coupled to the automatic transmission;
• a first axle operatively coupled to the internal combustion engine and the automatic transmission;
• a second axle;
• an electric motor-generator operatively coupled to the second axle;
• a pressure source in fluid communication with the plurality of clutches;
• a plurality of valves, each valve being in fluid communication with the pressure source and at least one of the clutches;
• and
• a controller in electronic communication with the pressure source and the plurality of valves, the controller being configured to:
• determine an initial gear ratio of the transmission based on a gear shift map while the vehicle is solely driven by the electric motor-generator;
• identify potential clutches of the plurality of clutches based on the initial gear ratio;
• determine a temperature of the transmission fluid;
• determine which of the potential clutches has a largest fill time based at least in part on the temperature of the transmission fluid in order to identify at least one of a plurality of target clutches;
• determine a target gear ratio of the transmission based on the at least one identified target clutch;
• and
• send an activation command to the pressure source to turn on the pressure source;
• and
• before the internal combustion engine is started, send pressure commands to the valves that are in fluid communication with the potential clutches used to select the target gear ratio in order to transfer sufficient transmission fluid to the at least one identified target clutch to reach a pressure threshold in the at least one identified target clutch to thereby minimize a time necessary to transfer torque from the internal combustion engine to the first axle through the automatic transmission once the internal combustion engine is started.