| After entering 21st century, because of the development of industry, the demand for the energy , such as petroleum , coal ,electricity etc of the whole world is increasing constantly. A lot of countries face the phenomenon of the energy shortage. Even more like this in our country, because of the energy deficiency, a lot of provinces have already begun to ration the power supply. It is obvious that it is an extremely urgent problem to implement the power-saving technology in national economy. And since reform and opening-up, with the development of our national economy and need of national economic construction, the demand of the hydraulic excavator is increasing constantly. Efficiency of domestic hydraulic excavator cannot compare with those have been produced by some known foreign enterprises because of unadvanced technique, so they waste more energy. In order to change the situation, we research and develop the energy- saving control system of the hydraulic excavator.When the hydraulic excavator works, diesel engine drive the hydraulic pump, handle the chief valveï¼›Hydraulic pump carry high-pressure oil to executive component, executive component drive relevant organ to work.Now, the domestic large-and-middle-scale hydraulic excavator generally adopts the diesel engine to urge the variable pump to carry on the work. When working, accelerograph' position of the diesel engine is set for by driver according to experience basically, which is seldom changed. This Cause the output power of the diesel engine in most instances to be greater than the real necessary power, and cause "the big horse to draw the little car ", wasting energy.In order to change this kind phenomenon of power wasting in mismatch of power of variable pump and diesel engine, this text has analyzed the full-load speed characteristic of the diesel engine,some load tempo characteristics and characteristics of variable pump at first, at the same time,Understand in-depth the brake characteristic the rotative system . Secondly, this text has analyzed in detail the characteristic of each operating status in a work cycle of hydraulic excavator. On the foundation of the above analysis, combining one's own characteristic of the hydraulic excavator and working environment, we design the power-saving control system of the hydraulic excavator. this System consists of accelerograph control cell,speed control cell and switching power control cell. The essence that the speed controls is to regulate the Displacement of variable pump according to the change of the speed of diesel engine caused by exterior load' changes. So we can make the speed of the diesel engine keep realizing under the establishing value,achieving speed closed loop control. Accelerograph control cell make throttle position basic stability according to windage between initialization and measure value. Switching power control pressure value of cell divide each work cycle into two pieces of course according to pressure value of pump and brake signal, course 1 is controlled back mainly, according to every parameter value under the selected mode, course 2 is controlled according to necessary power value in gyration course.In the analysis and design of the control system, we should set up systematic mathematics model firstly. The mathematics model of the control system is the mathematics expression formula to describe the physical quantities within the system. After receiving this mathematics expression formula, we can analyze about performance of the system. Systematic emulation can give experiment and practice instruct, it can also make people avoid detours in design work; revise each parameter of the system in time. Though, the emulation result can not at all accord with practicing, but provide direction in which the system revises theoretically. We have set up the mathematics model of the control module of the throttle control cell for this. Because of complicated physics , chemical change in the course of work of the diesel engine, it is very difficult to describe chara...
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