In the past few years, considerable effort has been
made to improve the power efficiency of electrohydraulic
systems; many energy saving strategies have been
successfully developed and used. However, most of them can only be useful in specific applications. For instance, displacement control and secondary control only focus on those systems in which the efficiency concerns are more important. Although these systems have very high efficiency,
they are not designed for applications in which the flow rate is varied during the duty cycle. Compared with pump controlled systems and other energy efficient systems, the valve controlled system demonstrates good dynamic performance and controllability especially for inertia
dominated loads but at the expense of power efficiency. For electrohydraulic circuits which employ load-sensing systems for example, the design objective has been made to combine the advantages of high dynamic performance with better energy utilization. However, this high efficiency can only be obtained under particular operating conditions, such as single-load or multi-loads with similar load pressure requirements. No one approach is available for general system design where both good dynamic performance and high-power efficiency are important.
The objective of the present paper is to highlight the different technological processes used for improving the performance of efficient electro-hydraulic circuit in energy saving.