Excavator hydraulic system having engine start/stop function and adopting active pressure-adjusted type pressure common rail

Abstract

The invention discloses an excavator hydraulic system having an engine start / stop function and adopting an active pressure-adjusted type pressure common rail. The excavator hydraulic system comprises a hydraulic pressure control system and an executing mechanism, wherein the hydraulic pressure control system comprises a controller, a main pump, a variable oil cylinder and a servo valve; the controller servo valve is used for controlling the displacement of the variable oil cylinder; the variable oil cylinder directly drives a tilting tray of the main pump to rotate to finish the control over the displacement of the main pump so as to control the pressure of a high pressure pipeline. According to the excavator hydraulic system disclosed by the invention, aiming at the problem that the real-time efficiencies of various hydraulic elements have relatively large difference under different working conditions, a hydraulic executing element can be adjusted to work in an optimal efficiency combination manner because the freedom degree of pressure change of the high pressure pipeline is increased, and thus the purpose of improving the efficiency of the whole hydraulic system is achieved; furthermore, the engine can be paused when the excavator is at a standby state by controlling a start / stop mode of the engine, and thus the energy can be further saved.

Description

technical field [0001] The invention relates to an excavator hydraulic system, in particular to a hydraulic system of a pressure common rail-based hydraulic hybrid excavator with an active pressure regulation function. Background technique [0002] In recent years, under the background of energy shortage and increasing environmental pollution, research on energy saving and emission reduction of hydraulic systems, which generally have the disadvantages of low efficiency and poor emissions, has become a hot spot. Although the existing energy-saving methods for hydraulic systems have played an important role in improving efficiency, they still have obvious disadvantages. For example, the use of hydraulic valve-controlled throttling speed regulation systems results in low work efficiency due to the inevitable throttling loss ( The hydraulic system efficiency of the excavator is mostly below 30%), and it is difficult to recover energy; in addition, the system that uses pump contr...

AI Technical Summary

Problems solved by technology

However, in practical applications, this ideal constant pressure oil source is difficult to achieve, especially in the field of mobile construction machinery to which excavators belong, or in other words, providing an ideal oil source requires a high cost, or even impossible, of the general application system. Tolerated cost (requiring high-power pump and large-capacity hydraulic accumulator); in addition, because the efficiency of the axial piston variable element used in the system varies greatly with the working state, for example, the axial piston of 18ml / r Under the premise of the same pressure difference and speed, the volumetric efficiency of the full displacement hydraulic pump / motor will drop from 0.92 to 0.31 at 50% displacement, and under the condition of the same output torque, "constant pressure" will limit The degree of freedom to adjust the working range of the components, so "constant voltage" will inevitably cause the components to sometimes work in the low-efficiency area and affect the energy consumption of the whole machine

Images