Electro hydraulic proportional control has been applied in engineering machinery in the early 80's, to the presentalready in hydraulic excavator has been used in large scale. The electro-hydraulic proportional technology used in engineering machinery, eliminates the need for complex, large hydraulic signal transmission line, electric signal transmission hydraulic parameters, not only can speed up the system response, and the dynamic system of excavators control more convenient, flexible. After entering 90 age, along with the development of computer technology, electro-hydraulic proportional control more "intelligent", application of electro-hydraulic proportionalpump and the proportional valve is increasing, thus the emergence of the "intelligent hydraulic excavator". Thisintelligence is mainly reflected in the following aspects. First of all, the computer can run parameter automaticmonitoring of hydraulic system and diesel engine, such as pressure, engine speed, and can automatically control the excavator power system running in the high energy state according to these parameters. Secondly, to do somesemi automatic operation, such as the ground, slope trimming, reduce the required proficiency drivers, but the quality of work can be greatly improved. Third, to carry out fault diagnosis according to the operating parameters to monitor, maintenance is convenient for excavator. The occurrence of these features, the excavator performance can be greatly improved.
Electro-hydraulic proportional control