Shifting fork control method during DCT (Dual Clutch Transmission) speed changer downshift process

Abstract

The invention discloses a shifting fork control method during a DCT (Dual Clutch Transmission) speed changer downshift process. The shifting fork control method during the DCT speed changer downshiftprocess comprises the steps: (1) after a TCU receives signals from the accelerograph opening, the vehicle acceleration and the vehicle speed, the TCU sends a downshift command signal to a hydraulic system, the hydraulic system loads oil pressure on a hydraulic cylinder on the downshift starting side, and a shifting fork moves from the downshift starting side to a neutral position under the actionof the oil pressure; (2) when the shifting fork moves to an optimal oil pressure unloading position, the TCU sends a command signal, so that the hydraulic cylinder on the downshift starting side unloads the oil pressure; and (3) the shifting fork moves to the neutral position under the action of inertia so as to accomplish downshift operation. According to the shifting fork control method during the DCT speed changer downshift process provided by the invention, during the downshift process, the inertia displacement of the shifting fork is compensated through unloading the oil pressure at an advanced position, so that the problems that the downshift quality is poor and even the downshift operation is failed since the shifting fork cannot accurately move to the neutral position through shifting fork inertia during the downshift process are solved.

Description

technical field [0001] The invention belongs to the technical field of transmission gear removal control methods, and in particular relates to a shift fork control method in the gear removal process of a DCT transmission. Background technique [0002] For the single-side hydraulic cylinder pressure control system for transmission shifting, if the oil pressure of the hydraulic cylinder is too high when the gear is removed, the shift fork will move faster. It will continue to move for a certain distance by virtue of inertia, causing the shift fork to over-shift, and in severe cases, it will also cause the shift fork to enter another gear, resulting in failure of shifting and affecting the safety performance of shifting; if the oil pressure of the hydraulic cylinder is too small, it will As a result, the moving speed of the shift fork is too slow, and the shifting time is longer, which affects the shifting quality. In order to improve the above problems, it is necessary to des...

AI Technical Summary

Problems solved by technology

[0003] The present invention proposes a shift fork control method for unloading oil pressure in advance at a proper position in a DCT transmission. The problem of poor quality or even failure to remove gears, and at the same time solve the problem of excessive gear removal due to inertia, and improve the quality of gear removal

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