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

For a power-split plug-in hybrid electric vehicle (PS-PHEV), the control system cannot effectively reduce jerks under some engine-starting conditions due to the pulsating torque of the engine, elastic characteristics of the transmission, battery power limitations, and the limitation of the maximum torque of the motor. To solve this problem, a dynamic torque-coordinated control method considering engine starting conditions (DTCC-ESC) is proposed in this paper. The proposed DTCC-ESC mainly includes three parts: the engine segment active control before and after engine ignition to minimize the impact of the engine ripple torque on the shocks of the powertrain system; the feedforward control of the engine starting conditions and the feedback control of the engine’s optimal target speed; and the active damping feedback compensation control for system resonance to reduce system vibrations. The results show that the proposed DTCC-ESC can effectively improve driving comfort under different engine starting conditions.

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Coordinated Torque, Energy and Clutch Control Strategy for Downshifts in P2 Parallel xHEV Powertrains

Robinette¹

2021

SAE Int. J. Adv. & Curr. Prac. in Mobility

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<div class="section abstract"><div class="htmlview paragraph">This paper describes a methodology for investigating the controls coordination of clutch and propulsion torque sources relative to clutch energy, electrification energy consumption and output torque profile for offgoing controlled downshifts in P2 parallel xHEV powertrain configurations. The focus is on an 8 speed planetary automatic transmission, but the approach is equally applicable to any powerflow design with clutch-to-clutch shifting. The modeling technique is for an overall control strategy relative to achieving a targeted transmission input speed profile. A reduced order model of the transmission system is presented that accounts for input shaft acceleration and compensation of inertial contributions to offgoing clutch torque and transmission output torque. The coordinated control of offgoing clutch, engine and P2 electric motor torques are explored in the context of power on and off downshifts for clutch energy, P2 energy consumption and output torque trajectory that directly translates to responsiveness and/or perceived shift quality. The presence of a torque converter and lockup clutch and the influence of the lockup clutch state control on downshifting coordination and torque disturbance is also incorporated in the analysis. Potential improvements in downshift response, clutch controllability and output torque trajectory are provided for the particular 8 speed transmission powerflow considered. The methodology presented can easily be applied to any clutch-to-clutch transmission architecture and powerflow, whether planetary, dual clutch or other.</div></div>

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

Cited by 6 publications

References 33 publications

Upshift optimization control of dedicated hybrid transmission with P2 configuration

Upshift optimization control of dedicated hybrid transmission with P2 configuration

Dynamic Torque Coordinated Control Considering Engine Starting Conditions for a Power-Split Plug-In Hybrid Electric Vehicle

Coordinated Torque, Energy and Clutch Control Strategy for Downshifts in P2 Parallel xHEV Powertrains

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