Gm Global Technolgoy Operations, Inc.

Michael D Potts

Paul S Lombardo

Shaochun Ye

Anthony L Christman

Jeffrey R Aldrich

Anthony Burt

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.

Powertrain with engine start function using resettable engine speed profile

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 (T). The controller is programmed to calculate a first motor torque pulse command (T) for the first motor/generator as a product of a first gear factor (G), the engine pulse torque (T) and a first ratio (I/I) of a predetermined first moment of inertia (I) for the first motor/generator and a predetermined engine moment of inertia (I). Similarly, the controller is programmed to calculate a second motor torque pulse command (T) 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.

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South Lyon, MI, United States of America

Michael D Potts