A control method for mode switching of a single-motor parallel hybrid electric vehicle

Abstract

The invention discloses a single-motor parallel hybrid vehicle mode switching control method. According to the control method, the overall mode switching process is divided into four stages which are respectively an engine start stage, an engine-motor rotating speed synchronization stage, a clutch engagement stage and an engine-rotor torque adjustment stage; in each stage, vehicle longitudinal impact caused by dynamic torque of an engine or a clutch can be inhibited by active control of a motor; active control of the motor adopts a composite control method based on combination of feedforward-linear secondary feedback control and robust compensation control; the feedforward-linear secondary feedback control is mainly used for controlling a nominal linear system; the robust compensation control is mainly used for inhibiting influences of indeterminate factors such as uncertainty of vehicle parameters, engine / clutch torque fluctuation and changes of vehicle running resistance and the like. The method disclosed by the invention is capable of improving the longitudinal driving performance of the vehicle during a mode switching process and reducing abrasion of clutch members, and is also relatively high in robustness.

Description

technical field [0001] The invention belongs to the field of control of hybrid electric vehicles, and in particular relates to a control method for a single-motor parallel hybrid vehicle from a pure electric drive mode to a hybrid drive / engine drive / engine drive and charging mode switching process. Background technique [0002] When a single-motor parallel hybrid vehicle is running at a low speed in pure electric mode, if the driver suddenly steps on the accelerator pedal or the power battery is low, the vehicle will switch from pure electric drive mode to hybrid drive / engine drive / engine drive and charging mode . For a single-motor parallel hybrid vehicle, it is necessary to start the engine by engaging the clutch, and quickly synchronize the engine and the motor to achieve mode switching. The entire mode process includes a series of transient processes such as engine start, clutch engagement, and sharp changes in engine and motor torque, which can easily lead to sudden ch...

AI Technical Summary

Problems solved by technology

[0004] In the control method described in this patent, when the engine is ignited and started to gradually synchronize with the motor speed, the clutch is always in a slipping state, and the slipping work will increase. Especially in urban working conditions, hybrid vehicles frequently switch between such modes It will further aggravate the wear of the clutch and affect the service life of the clutch

Secondly, due to the strong nonlinear characteristics of the clutch friction torque and the dynamic torque of the engine, the control method described in this patent only considers the steady-state components of the dynamic torque of the engine and the clutch, ignoring the dynamic torque The fluctuation component will make the dynamic torque estimation of the engine and the clutch inaccurate, and the drive motor cannot accurately compensate the dynamic torque of the engine and the clutch, which will affect the actual effect of the coordinated control of mode switching

In addition, the control method described in this patent does not consider the influence of vehicle parameter changes (such as vehicle mass, gear position) and external driving resistance changes on the coordinated control performance, and the robustness of the coordinated control method is poor

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