Abstract: A hybrid electric powertrain includes an electric machine delivering torque to an engine in an engine start event having initial cranking and transition phases. In response to a request for an engine start event, a controller commands delivery of the motor torque to the crankshaft. In the initial cranking phase the controller regulates crankshaft acceleration from zero speed up to a target cranking speed in a closed-loop manner via a predetermined fixed profile. In the transition phase, the crankshaft accelerates from the target cranking speed to a target idle speed using a feed-forward torque value blended, using a calibration table, from a predetermined engine drag torque to a reported engine torque. In the transition phase the controller periodically adjusts a speed trajectory of the crankshaft, with the magnitude and frequency of adjustment based on combustion of the engine and calibration of the feed-forward torque.

Abstract: A hybrid electric powertrain includes an electric machine delivering torque to an engine in an engine start event having initial cranking and transition phases. In response to a request for an engine start event, a controller commands delivery of the motor torque to the crankshaft. In the initial cranking phase the controller regulates crankshaft acceleration from zero speed up to a target cranking speed in a closed-loop manner via a predetermined fixed profile. In the transition phase, the crankshaft accelerates from the target cranking speed to a target idle speed using a feed-forward torque value blended, using a calibration table, from a predetermined engine drag torque to a reported engine torque. In the transition phase the controller periodically adjusts a speed trajectory of the crankshaft, with the magnitude and frequency of adjustment based on combustion of the engine and calibration of the feed-forward torque.

Abstract: A powertrain assembly includes a transmission, an engine, first and second motor/generators and a controller. The controller includes a processor and memory on which is recorded instructions for executing a method for controlling engine pulse torque cancellation commands. The controller is programmed to determine an engine pulse torque (TP). The controller is programmed to calculate a first motor torque pulse command (TA) for the first motor/generator as a product of a first gear factor (G1), the engine pulse torque (TP) and a first ratio (IA/IE) of a predetermined first moment of inertia (IA) for the first motor/generator and a predetermined engine moment of inertia (IE). Similarly, the controller is programmed to calculate a second motor torque pulse command (TB) for the second motor/generator. The controller is programmed to control the first and second motor/generators in response to the first and second motor torque pulse commands, respectively.

Abstract: A powertrain assembly includes a transmission, an engine, first and second motor/generators and a controller. The controller includes a processor and memory on which is recorded instructions for executing a method for controlling engine pulse torque cancellation commands. The controller is programmed to determine an engine pulse torque (TP). The controller is programmed to calculate a first motor torque pulse command (TA) for the first motor/generator as a product of a first gear factor (G1), the engine pulse torque (TP) and a first ratio (IA/IE) of a predetermined first moment of inertia (IA) for the first motor/generator and a predetermined engine moment of inertia (IE). Similarly, the controller is programmed to calculate a second motor torque pulse command (TB) for the second motor/generator. The controller is programmed to control the first and second motor/generators in response to the first and second motor torque pulse commands, respectively.