Method for controlling speed ratio of hybrid electric vehicle in driving process

Abstract

A method for controlling the speed ratio of a hybrid electric vehicle in the driving process comprises the steps that S1, a signal related to speed ratio control is received; S2, an efficiency graph of an engine and an efficiency graph of a motor are measured through experiments and optimal economical curves of the graphs are made respectively; S3, the optimal economical rotating speed of the engine under the required power and the optimal economical rotating speed of the motor under the required power are respectively calculated; S4, considering the required power ratios of the engine and the motor and influence, caused by the rotating speed, on the efficiency, the target rotating speed is calculated; S5, the target speed ratio is calculated through the target rotating speed, the vehicle speed and the main speed reducing ratio; S6, the target speed ratio is sent to a speed ratio control actuator to be executed. According to the method for controlling the speed ratio of the hybrid electric vehicle in the driving process, when the vehicle is driven in a hybrid mode, the ratios of work of the engine and work of the motor and different influences, caused by the rotating speed, on the efficiency of the engine and the efficiency of the motor are fully considered, so that the optimized target speed ratio is obtained, and the method enables the economical efficiency of the vehicle to be improved.

Description

technical field

[0001] The present application relates to the technical field of vehicle drive control, in particular to a speed ratio control method and system for parallel strong hybrid vehicles (including plug-in strong hybrid vehicles). Background technique

[0002] With the global energy shortage and environmental pollution caused by automobile emissions becoming more and more serious, it has become the consensus of all walks of life to promote new energy vehicles with low energy consumption and low emissions. Hybrid vehicles are the first choice for large-scale industrialization at present. With the increasing demand for performance and comfort, it is necessary to develop hybrid vehicles with automatic transmissions, especially continuously variable transmissions. Compared with manual transmissions or stepped automatic transmissions, continuously variable transmissions have greatly improved driving comfort and power. The main reason is that the speed ratio of the conti...

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