Control method for full-power power shifting of hydraulic-mechanical stepless transmission

Abstract

The invention provides a control method for full-power power range shifting of hydro-mechanical stepless transmission. The control method comprises the following steps: a hydro-mechanical controller monitors key state parameters such as the rotating speed, the pressure and the like of the current range in real time; a ratio of the rotating speed of a constant-displacement hydraulic component to an input rotating speed is taken as a criterion of ideal timing for range shifting; a clutch in a target range engages at the ideal range shifting timing, hydraulic machinery enters a previous stable range from the current range; the controller predicts the working state of the target range according to the key state parameters of the current range and plans a displacement regulation process in a power transition process; pressure release and pressure building processes on high-pressure and low-pressure sides of a closed hydraulic circuit are controlled actively by regulating the displacement of the constant-displacement hydraulic component according to the planned displacement regulation process in a power transition range, and power transition is realized; after completion of power transition, range shifting enters a later stable range; finally, a clutch in the current range disengages, range shifting is completed, and the hydraulic machinery enters the target range. With adoption of the range shifting control method, range shifting of the hydraulic machinery is completed in combination and overlapping of the two clutches, and stable transition from the current range to the target range is realized; power can be transmitted normally during range shifting, and full-power power range shifting is realized.

Description

technical field [0001] The invention relates to the technical field of hydraulic mechanical stepless transmission, in particular to a method for controlling full-power power shift of hydraulic mechanical stepless transmission. technical background [0002] The hydromechanical stepless transmission is a transmission form composed of mechanical transmission and hydraulic transmission, such as figure 1 As shown, it consists of four parts: power splitting mechanism D, mechanical transmission mechanism M, hydraulic transmission mechanism H, and power converging mechanism C. This transmission method has the outstanding advantages of high efficiency of mechanical transmission and stepless transmission of hydraulic transmission, and is suitable for use in high-power vehicles. [0003] The segment change process of hydromechanical stepless transmission is a transition process in which two adjacent segments alternate. During the section change, the load of the hydraulic transmission...

AI Technical Summary

Problems solved by technology

During the section change, the load of the hydraulic transmission mechanism is reversed, the power flow of the hydraulic circuit is reversed, the functions of the hydraulic components are interchanged, and the high and low pressure sides of the hydraulic circuit are interchanged, resulting in a sudden change in the speed of the constant displacement hydraulic components, causing fluctuations in the output speed, and causing power interruption

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