1.Negative flow control
This system is designed to eliminate the throttling loss caused by the valves are used. The specific method is to set up a flow detection device on the median return line of the six-way valve, and use this signal to control the displacement of the hydraulic pump so that the flow rate through the median return tank is always kept at a very small constant value. Thus, the median return power loss can be greatly reduced or even basically eliminated.
2.Pressure cut
The function of pressure cut is to eliminate the overflow loss when the system is overloaded, The pressure cut function enables the pump to further reduce the displacement when approaching the overflow pressure of the system, maintain the system pressure at the so-called cut off pressure, slightly lower than the overflow pressure, and avoid the overflow loss.
3.Positive Flow Control System
Positive flow control is the direct control of pump displacement by using the pilot pressure of the control handle, and the speed and direction of the hydraulic cylinder are controlled by six-way multi-way valve. The maximum pilot pressure needs to be selected through the shuttle valve group to control the displacement of hydraulic pump.
4.Load sensing control system
In the load sensing system, single pump oil supply can be used to simplify the design of hydraulic system, but the structure of load sensing valve is complex and the cost is high. Although the excavator is more manipulative, it is at the cost of power loss on the pressure compensator, so some foreign excavators can change the set value of the pressure compensation valve according to the specific working conditions. To meet the working habits of some skilled drivers, reduce losses.