Mechanical type automatic transmission gear shifting method

Abstract

The invention relates to a mechanical type automatic transmission gear shifting method. The mechanical type automatic transmission gear shifting method includes the following steps that the current vehicle mass and the current slope are acquired; with the maximum acceleration which a vehicle can reach as a power performance index, a best power performance gear position under different vehicle speeds, different accelerations, different accelerator opening degrees, different masses and different slopes is calculated, and serves as a vehicle power performance gear shifting strategy; with the motor efficiency being an economic index, on the basis that the slope climbing requirement of the vehicle is met, a best economy gear position under different vehicle speeds, different accelerations, different accelerator opening degrees, different masses and different slopes is calculated, and serves as a vehicle economy gear shifting strategy; and the current power performance and economy requirements of the vehicle are judged, one of the vehicle power performance gear shifting strategy and the vehicle economy gear shifting strategy is selected to determine a gear shifting point. For different masses of the vehicle and different slopes of a road, an optimal gear shifting strategy is calculated; by means of a multi-target optimization method based on road condition information and a vehicle state, the gear shifting strategies are optimized, so that the intelligent level of gear shifting can be improved, frequent gear shifting is avoided, and power performance and economy of the vehicle become best.

Description

technical field [0001] The invention relates to the technical field of stepped automatic transmissions for automobiles, in particular to a gear shifting method for mechanical automatic transmissions of electric vehicles that integrates road gradient and vehicle quality identification. Background technique [0002] The shift strategy defines the control parameters of the gear decision and the shift timing determined by these parameters, which has an important impact on the vehicle's power, economy and other performances, and is one of the core technologies of the automatic transmission system. [0003] According to the difference of control parameters, the currently widely used shift strategies include the two-parameter shift strategy based on vehicle speed and accelerator opening and the three-parameter shift strategy based on vehicle speed, acceleration, and accelerator opening. and constant quality, but the road slope is constantly changing in actual operation, and the wei...

AI Technical Summary

Problems solved by technology

[0004] Shifting strategies are divided into power shifting and economical shifting. For different vehicle operating conditions and driver intentions, it is an inevitable requirement for the development of automatic shifting technology to select different shifting strategies in real time. At present, thresholds based on road gradients are mostly used. Carry out switching and shift strategy selection based on driver style judgment. Switching based on road gradient only considers road conditions, but does not take the driver and vehicle status into account. Shift strategy selection based on driver style judgment is difficult to meet changing requirements. Different needs of vehicles under working conditions

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