Analysis of energy saving control development
efficiency, more importaIn the field of energy saving control of hydraulic excavator, the aim is not only to improve fuel nt is to obtain a series of lower cost effect. Data shows, construction machinery failure nearly 40% from thehydraulic system, about 15% of the failures come from engine. The application of energy saving technology, which can improve the utilization rate of engine power, reduce the power loss of hydraulic system, the power system with load required power better matching, reduces the work intensity of engine and hydraulic components, and improves the reliability of equipment in use.
From the domestic and international development situation, the energy-saving control of hydraulic excavator has the following trends:
1) electro-hydraulic proportional control
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.
2) electronic fuel injection control
In the mechanical speed diesel traditional machine, the fuel cycle, fuel pump, fuel injection advance angle are speed influence, to further improve the performance of the diesel engine. Application of electronic control on diesel engine,can make the pump cycle fuel quantity and injection advance angle is no longer affected by speed, so that theexcavator can always work in the best condition, and speed up the response. Development of electronic fuel injection controller is an important link of improving energy efficiency of excavator.
3) load sensing control will continue to develop
Load sensing control from twentieth Century 70 time began to rise, manufacturers of hydraulic engineering machinery have launched a series of related products. This system has a good energy-saving and maneuverability,even unskilled operators can quickly adapt to. Appear proportional flow distribution valve and further promote theapplication of load sensing technology in excavator, excavator control to further improve, the western countries due to the lack of skilled drivers problems. Therefore, the demand of load sensing control excavator in developed countries will continue to rise.
4) the six way multiple valve continue to exist
Although the load sensing system using four way valve to provide accurate operation, but not all occasions needprecise operation, and skilled drivers can complete precise operation non load sensing system for excavator. More important is, the higher price of load sensing system, limit its application in developing countries. At present, many of the world's famous excavator manufacturers, their products in both load sensing control excavator using four valve,also use the six way valve hydraulic system such as negative control, positive rate of excavator. Mature manufacturing technology and low prices will make the six way multiple valve continues to play a role.
5) to further improve the energy-saving control valve control
In the hydraulic system of the six way multiple valve, there are still many improvements, such as operation, energy saving, so far the excavator factory are still in research.
6) multi function combination
In order to improve the performance of excavator, combined with a variety of energy-saving measures will be more and more extensive. In the former system, the hydraulic pump has integrated a variety of functions, but due to various limitations, generally not more than three. Such as hydraulic pump as shown in Figure 14, is integrated with the pressure off, positive flow control and power restriction function, all kinds of hydraulic pump schematic diagram is very popular on the market, are integrated with multiple functions. With the development of hydraulic technology,has the potential to integrate more functions on the pump.
7) variable parameter control
In order to better meet the requirements of excavator load under various conditions, set the parameters of powersystem of internal control elements will no longer be a fixed value, but can change along with the specific working conditions of excavator. For example, EX series excavator in Hitachi construction machinery production, pressure compensator load sensing valve pressure setting on the change with working conditions, enhance the adaptability of the excavator work. Can be predicted, in the dynamic system of excavators in the future, there will be more control parameters can be adjusted, so that the work efficiency is more high, more easy to manipulate the excavator.
8) pump engine matching control will further "intelligent"
With the help of computer control technology, matching control pump and the engine will achieve "intelligent" further,the combination of the two will be more closely, to realize the integration of control. In this control, the controller canroot