Overview and Development of Energy saving Technologies for Hydraulic Systems in Construction Machinery

1. Energy saving technology for hydraulic system of construction machinery
1.1 Energy saving technologies for hydraulic systems
The energy-saving of hydraulic systems in construction machinery requires the use of energy-saving hydraulic components. The energy consumption of energy-saving hydraulic components is generally concentrated in areas such as oil leakage and internal friction, where there are losses in flow rate and pressure. The common energy conversion components in hydraulic systems of construction machinery include hydraulic pumps, hydraulic motors, and hydraulic cylinders. The energy loss of these components is relatively high, while some other components have relatively low energy consumption. The current optimization from energy-saving hydraulic components is to replace the gear structure with a blade structure, and after a series of developments and advancements, form a plunger structure. The improvement is not only in load speed, but also in volumetric efficiency and mechanical efficiency. The commonly used energy-saving component in industrial production is the plunger pump, which can greatly reduce energy consumption caused by friction. In this process, special materials are applied to the surfaces of some inclined plates, plungers, and cylinder bodies to achieve the goal of reducing energy consumption. Another aspect is the optimization and improvement of hydraulic pumps, which enriches the variable control methods of hydraulic pumps.
In addition, power matching technology for hydraulic systems has also improved the energy-saving effect of construction machinery. This technology largely solves the coordination problem between the output power of the hydraulic system and the load characteristic curve, reduces the loss of flow and pressure, and improves the energy utilization efficiency of the hydraulic system. Although the power matching technology of hydraulic systems is still in the stage of development and improvement, its prospects are very broad. The control technology for positive and negative flow is also constantly improving. Positive flow mainly relies on the pilot control pressure of the main control valve core, while negative flow is controlled by the hydraulic pump to achieve displacement control. The energy-saving technology of hydraulic systems in construction machinery is also reflected in the development and improvement of load sensing control systems. Load sensing control systems can provide feedback on load flow and pressure, which can be achieved through electro-hydraulic signals, promoting the adaptation and matching between load pressure and system flow. In addition, the prominent energy-saving technology in hydraulic systems of construction machinery is diesel engine injection control, as diesel engines are the power source of hydraulic systems in construction machinery. Electronic fuel injection control technology can improve the sequential quantity of the fuel injection pump and ensure that the speed does not affect the operation of the fuel injection pump, greatly improving work efficiency.
1.2 Recycling and reusing energy technology
The technology of energy recovery and reuse is closely related to engines. *The engine will output and load energy during operation, thereby achieving the recovery and reuse of energy. This technology is applied in energy-saving technology for hydraulic systems in construction machinery, and has a positive effect on reducing mechanical energy load and negative power input forms. This technology can effectively prevent various mechanical equipment damage caused by high system temperatures. Specifically, the excess kinetic energy generated by the engine can be effectively utilized, and not only that, the mechanical energy of the load during engine operation can also be recovered and utilized. For example, common ones in real life include cranes, hydraulic elevators, etc. Generally, the hydraulic pump will only be driven and rotated by the engine when the energy required by the load during the operation of the hydraulic system is relatively small compared to the output energy of the engine. During this process, the kinetic energy output by the engine is surplus and can be converted into hydraulic energy for storage for other purposes. Regarding the recovery and reuse of load kinetic energy, emphasis is placed on the walking mechanism and the rotating mechanism, which have a positive effect on the rotating load. The hydraulic control system adopts a left-right symmetrical design, which is conducive to energy recovery and reuse, especially when the rotary brake is used, the energy recovery and reuse effect will be better, and energy-saving effect can be achieved.
Development direction of energy-saving technology for hydraulic systems of construction machinery
From many practical experiences and scientific research, it can be found that there is a connection between the energy-saving level of hydraulic systems and the energy recovery and reuse of hydraulic systems. In order to ensure energy-saving effects, optimization and improvement are carried out for energy-saving hydraulic components. Currently, there are still some technical difficulties in the power matching technology and energy recovery technology of the grandfather system, which need to be continuously improved in future development. Specifically, the use of energy-saving hydraulic components can produce energy-saving effects, but the effect is small and the development speed is not fast. In addition, the power matching technology of hydraulic systems is relatively weak and cannot meet the energy-saving requirements of hydraulic systems in construction machinery. The most common problem is local power matching, which has a wide range of applications. From the perspective of energy recovery, the development prospects of energy-saving technology for hydraulic systems in construction machinery rely on pumps for energy storage in terms of components. However, China currently does not have the technical conditions to produce pumps and needs to continuously purchase technical products from other countries. In addition, in terms of system control, although there is already an energy recovery and reuse hydraulic system, the control strategy is relatively single and cannot meet the complex energy utilization requirements. So in the future, the development direction is still to achieve fuel consumption reduction and improve energy management efficiency. In the future, we can start with the use of energy-saving hydraulic components to accelerate development, improve the component structure of hydraulic systems, and reduce energy consumption. We should actively improve the power matching technology of hydraulic systems, take optimization measures for load sensing control systems, and continuously increase the technological content.
3 Conclusion
In the future development of the world economy, the concept of energy conservation and emission reduction will become more deeply rooted in people's hearts and penetrate into all aspects of industrial development. The continuous improvement of energy-saving technology for engineering machinery hydraulic systems is also a basic guarantee to ensure the continuous advancement of the concept of energy conservation and emission reduction. There is still a big gap between China's economic development and that of developed countries, which requires China to continuously optimize its development methods and engineering machinery and equipment in order to narrow it. It is necessary to absorb advanced experience from other countries and improve China's industrial development level.