CVT speed ratio optimization and energy management method for plug-in four-wheel drive hybrid vehicle with CVT

Abstract

The invention discloses a CVT speed ratio optimization and energy management method for a plug-in four-wheel drive hybrid vehicle with a CVT. The CVT speed ratio optimization and energy management method comprises the steps of firstly dividing operation modes into a rear-wheel drive motor driving mode, a double-motor driving mode, a pure engine driving mode, a hybrid mode, a driving-charging modeand a braking mode, then taking the maximization of the total efficiency of a front-axle power transmission system as the optimization objective, utilizing an instantaneous optimization method to separately optimize CVT speed ratios in the double-motor driving mode, the pure engine driving mode, the hybrid mode and the driving-charging mode so as to obtain CVT target speed ratio MAP graphs of thecorresponding four operation modes, finally determining the operation mode of the whole vehicle according to the vehicle speed, required torque of the vehicle and a battery SoC value, and determiningthe torque of an engine, a rear-wheel drive motor and an ISG motor and a target speed ratio of the CVT according to the operation mode. The CVT speed ratio optimization and energy management method for the plug-in four-wheel drive hybrid vehicle with the CVT improves the efficiency of a CVT plug-in four-wheel drive hybrid power transmission system and reduces the fuel consumption and emissions ofthe whole vehicle.

Description

technical field [0001] The invention relates to the technical field of hybrid electric vehicles, and more specifically relates to a CVT speed ratio optimization and energy management method of a CVT plug-in four-wheel drive hybrid vehicle. Background technique [0002] There are not many plug-in four-wheel drive hybrid vehicles currently on the market, and the transmission systems equipped are mainly dual-clutch transmission (DCT) and electromechanical automatic transmission (AMT). Continuously variable automatic transmission (CVT) is rarely used in plug-in four-wheel drive hybrid vehicles, and only some parallel two-wheel drive plug-in hybrid vehicles use CVT as a transmission. Cars using CVT often use automatically controlled stepless shifting, which improves the fuel economy of the vehicle, and improves the power and ride comfort of the vehicle. [0003] Compared with CVT plug-in two-wheel drive hybrid vehicles, CVT plug-in four-wheel drive hybrid vehicles have more powe...

AI Technical Summary

Problems solved by technology

[0004] In view of this, the present invention provides a CVT speed ratio optimization and energy management method for a CVT plug-in four-wheel drive hybrid electric vehicle, to solve the CVT speed ratio optimization and energy management problems of a CVT plug-in four-wheel drive hybrid electric vehicle, and further improve the overall performance. Vehicle fuel economy and emissions issues

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