Method and system for controlling parking and downshift of automatic transmission

Abstract

The invention relates to the technical field of transmission control, in particular to a method and system for controlling parking and downshift of an automatic transmission. The method comprises the following steps: calling a shifting figure inquiring curve generated in advance, and obtaining the target gear of the current vehicle; monitoring and judging the deceleration of an output shaft of the transmission of the current vehicle or the deceleration of the whole vehicle; when the vehicle condition of emergent deceleration occurs, correcting the obtained target gear by calling a gear correction matrix, and thus obtaining the corrected target gear; according to the current gear of the vehicle and the corrected target gear, controlling the vehicle to execute gear shifting operation when a shifting delay time is achieved; when the vehicle condition without emergent deceleration occurs, continuing to execute the step of monitoring and judging the deceleration of the output shaft of the transmission of the current vehicle or the deceleration of the whole vehicle. Therefore, the shifting control for the automatic transmission in the parking and downshift process is realized, frequent shifting is effectively avoided, two-step shifting is switched into single-step shifting, the shifting time can be greatly shortened, and the shifting quality is improved.

Description

Technical field [0001] The invention belongs to the technical field of gearbox control, and in particular relates to a method and system for controlling the parking and downshifting of an automatic transmission. Background technique [0002] Clutch shift control and shift strategy are the core control technology of hydraulic automatic transmission, which affect the driving performance and shift quality of the vehicle. However, shift control at low gears and low vehicle speeds is the technical difficulty of automatic transmission control. This driving condition often occurs in crowded urban traffic conditions, which is prone to frequent shifts and shift shocks. Because in crowded urban conditions, the driver's driving intention is very unclear during the start-stop process, and the accelerator and brake will often change irregularly. Therefore, it is difficult to achieve exchange through signal processing such as accelerator acceleration and braking. The delay control of gears af...

AI Technical Summary

Problems solved by technology

The shift control at low gears and low vehicle speeds is also a technical difficulty in automatic transmission control. This driving condition often occurs in congested urban traffic conditions, which is prone to frequent shifts and shift shocks.

Because in crowded urban conditions, the driver's driving intention is very unclear during the process of starting and stopping, and the accelerator and brake will often change irregularly. Therefore, it is difficult to realize the exchange through signal processing such as accelerator acceleration and braking Gear delay control, thus affecting the normal shift strategy

[0003] In addition, the change of accelerator and brake will also cause the torque and speed of the engine to be unstable, which will also increase the difficulty of clutch control, which will easily cause shift shock and drag feeling, thus affecting the shift quality.

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