Abstract: A vehicle powertrain includes an engine, transmission, torque converter assembly, and controller. The controller includes recorded lumped inertia models of the powertrain and instructions for executing a clutch-to-clutch shift using these models. The models collectively reduce powertrain dynamics to two or three degrees of freedom. The controller executes a method to estimate clutch torques using the models. The models may include a first primary inertia block describing engine inertia and inertia of a torque converter pump, and a second primary inertia model describing the inertia of the turbine and transmission as reflected to the input member. The second primary inertia model includes bulk inertia models for each fixed gear state and each possible shift maneuver. The controller derives a required output torque value as a closed-loop target value using the lumped inertia models and a requested input torque, and uses the estimated clutch torque to achieve the target value.

Abstract: A vehicle powertrain includes an engine, transmission, torque converter assembly, and controller. The controller includes recorded lumped inertia models of the powertrain and instructions for executing a clutch-to-clutch shift using these models. The models collectively reduce powertrain dynamics to two or three degrees of freedom. The controller executes a method to estimate clutch torques using the models. The models may include a first primary inertia block describing engine inertia and inertia of a torque converter pump, and a second primary inertia model describing the inertia of the turbine and transmission as reflected to the input member. The second primary inertia model includes bulk inertia models for each fixed gear state and each possible shift maneuver. The controller derives a required output torque value as a closed-loop target value using the lumped inertia models and a requested input torque, and uses the estimated clutch torque to achieve the target value.

Abstract: A control system for a powertrain includes an energy determination module and a speed control module. The energy determination module determines a rotational energy input to the powertrain during a first period of a negative lash event of the powertrain. The speed control module selectively limits an increase in a rotational speed of the engine to a first predetermined rate based on the rotational energy during a second period of the negative lash event following the first period. The rotational energy is based on an acceleration rate of the rotational speed, and the speed control module limits the increase when the acceleration rate is greater than a predetermined acceleration rate. The speed control module further selectively increases the rotational speed at a second predetermined rate during a third period beginning at an end of the second period. A related method is also provided.

Abstract: A control system for a powertrain includes an energy determination module and a speed control module. The energy determination module determines a rotational energy input to the powertrain during a first period of a negative lash event of the powertrain. The speed control module selectively limits an increase in a rotational speed of the engine to a first predetermined rate based on the rotational energy during a second period of the negative lash event following the first period. The rotational energy is based on an acceleration rate of the rotational speed, and the speed control module limits the increase when the acceleration rate is greater than a predetermined acceleration rate. The speed control module further selectively increases the rotational speed at a second predetermined rate during a third period beginning at an end of the second period. A related method is also provided.