| Energy-saving has been a key subject due to now worldly energy crisis. Hydraulic excavator, a high-power construction machinery, requires higher efficiency in energy using and transition. By introducing more and more electronic technology to hydraulic excavator system, electronic control for energy-saving has become leading direction in hydraulic excavator developing.The existing foreign hydraulic excavators have witnessed obvious energy-saving especially by equipped with different electronic control systems respectively, the famous systems that have improved energy-saving for different extent are as following: PMS system of O&K Company of Germany, CAPS system of Link-Belt; OLSS system of KOMATSU and EPOS system of Korean DAEWOO.Energy-saving of Hydraulic system has been titled as one of the key technologies listed in "Significant Assignment of Science & Technology Developing And Outline of Key Technologies" during the Ninth Five-Year Plan. Hydraulic excavator has been paid more and more attention for its importance among construction machineries.Computer Controlling System has been at exploring and in starting period in now China.Hydraulic excavator robot developed in Zhejiang University has controlled perfectly by incorporating Negative Flux Control, Positive Flux Control, Cross Power Control and Pressure Cut Off together.WY20-YC size hydraulic excavator, made in Guangxi Yuchai Limited Company, features electronic power regulating and three levels power pre-selecting but for high cost in producing which makes it difficult to be popularized.So energy-saving control research on domestic hydraulic excavator is of great significance both theoretical and experimental in strengthening competition. The dissertation, tied with the project (96250404) specially funded for excellent talents, analyzes present energy-saving technology on domestic hydraulic excavator and its primary energy-losing firstly, and then investigates energy-saving by incorporating the engine, variable pump and load to a dynamic system. The dissertation comes with advanced fuzzy control theory, introduces new way in energy-saving controlling as well as develops energy-saving fuzzy controller. The innovations in this dissertation are as following: 1. The dissertation analyzes present research situation of hydraulic excavator, comes with working principle of several advanced hydraulic excavator energy-saving control system as well as points out the research direction and developing trend of hydraulic excavator energy-saving, explains the purpose and significance of research on hydraulic excavator energy-saving control.2. Energy-losing and energy-saving control theory analysis (1) Analysis of hydraulic excavator energy-losingThe dissertation has put forward various ways of hydraulic excavator energy-losing when working via analyzing control circuits on hydraulic excavator. The primary energy-losing is through power matching between engine and pump as well as pressure causing flux loss arose by matching between hydraulic system and load, the rest loss is shared by the mechanic losing, kinetic energy-losing and potential energy-losing, pressure losing of pipeline and low efficiency of pump. (2) Analysis of hydraulic excavator energy-saving control theoryBy analyzing Universal Characteristic Curve and Speed Adjusting Curve of diesel engine, we know the maximum power point and the minimum oil consuming are at different rotation speed when the engine is at the same accelerator position, so it is important to set the engine rotation speed according to load. From Rotation Speed-Oil Consumption Curve, the oil consuming will see rising sharply when the rotation speed waves. The above analysis proves that steady rotation is of great importance to energy-saving. hydraulic excavator energy-saving can be realized via controlling on hydraulic pressure system and power system. The key to energy-saving is to control the flux of hydraulic system according to load regardless of which of the following has been chosen: Posit...
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