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Control Strategy and Energy Recovery Potential for P2 Parallel Hybrid Step Gear Automatic Transmissions

Published April 2, 2019 by SAE International in United States
Control Strategy and Energy Recovery Potential for P2 Parallel Hybrid Step Gear Automatic Transmissions
Sector:
Citation: Robinette, D. and Orlando, J., "Control Strategy and Energy Recovery Potential for P2 Parallel Hybrid Step Gear Automatic Transmissions," SAE Int. J. Adv. & Curr. Prac. in Mobility 1(3):1364-1382, 2019, https://doi.org/10.4271/2019-01-1302.
Language: English

Abstract:

The purpose of this investigation is to present a control strategy and energy recovery potential for P2 parallel hybrid step gear automatic transmissions. The automatic transmission types considered for the investigation are rear wheel drive 8 speed dual clutch transmission and 8 speed planetary automatic equipped each equipped with an electric motor between the engine and transmission. The governing equations of clutch-to-clutch upshift controls are presented and are identical for each transmission type. Various strategies are explored for executing the upshift under a range of input torques, shift times and engine torque management approaches. The differences in energy recovery potential based upon control strategy is explored piecewise as well as through a DFSS study. On a comprehensive drive cycle consisting of FTP 75, US06 and HWFET test cycles, it is shown that upshift regen torque management can be equivalent to approximately 0.8% of the total fuel energy used. Additionally, it is shown that the utilization of the P2 electric motor is a further enabler to reduced shift times and improved shift quality at part throttle without compromise to net battery energy or fuel consumption.