Vehicle power matching system with hydromechanical continuously variable transmission

Abstract

A vehicle power matching system with a hydraulic mechanical continuously-variable transmission can automatically adjust the transmission ratio of the transmission according to driving intentions of drivers and changes of an external load so that a driving system can provide enough power when in a transient state; during the transient state, an engine works at an optimal economical curve, and accordingly the system performance can be optimal. The vehicle power matching system has the advantages that the engine always works under the working conditions of optimal power performance and optimal economy; infinitely variable speeds are achieved rapidly and stably under the conditions of the driving intentions of the drivers and the changes of the external load; during the process, vibration noise is small, the overshoot is small, and offset is eliminated as far as possible; and the vehicle power matching system can meet the transient state power performance requirements and steady state economy requirements when a vehicle runs.

Description

technical field [0001] The invention relates to a power matching system, in particular to a vehicle power matching system with a hydromechanical stepless transmission. Background technique [0002] For a continuously variable transmission vehicle controlled by a traditional control strategy, once the economical or dynamic working mode is selected, the transmission ratio and throttle opening can only be changed according to the prescribed shifting rules, and cannot respond to changes in external loads and the driver's behavior in a timely manner. The operation intention can only reflect the control requirements of the transmission system itself. [0003] When the vehicle control strategy is the economy mode, when the driver wants to obtain better dynamics and depresses the accelerator pedal, the operating point corresponding to the engine accelerator opening is more economical than the dynamics. The dynamic performance cannot be realized; and when the vehicle control strateg...

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Problems solved by technology

[0002] For a continuously variable transmission vehicle controlled by a traditional control strategy, once the economical or dynamic working mode is selected, the transmission ratio and throttle opening can only be changed according to the prescribed shifting rules, and cannot respond to changes in external loads and the driver's behavior in a timely manner. The operation intention can only reflect the control requirements of the transmission system itself

[0003] When the vehicle control strategy is the economy mode, when the driver wants to obtain better dynamics and depresses the accelerator pedal, the operating point corresponding to the engine accelerator opening is more economical than the dynamics. The dynamic performance cannot be realized; and when the vehicle control strategy is the dynamic mode, although the transient dynamic requirements can be met, the economic efficiency of the vehicle in the steady state cannot be guaranteed.

[0004] When the vehicle control strategy is the economy mode, the external load changes suddenly, and the power provided by the engine is poor at this time, unable to provide power to overcome the external load, the vehicle speed drops suddenly, and even causes the engine to stall; while when the vehicle control strategy is the power mode Although it can meet the power performance requirements of the sudden change of external load, if the vehicle has been working under the dynamic control strategy, the economic performance of the vehicle cannot be guaranteed.

[0005] It can be seen that the pure economic control strategy and power control strategy cannot meet the power matching requirements of modern agricultural vehicles.

On the premise of ensuring the economy, it is difficult to meet the requirements of sudden changes in the external load during the operation of the vehicle

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