負荷敏感控製LS和與負載無關的LUDV液壓多路換向閥

Linde LSC 同步控製係統與負流量以及正流量控製係統的比較

 1. Main Control Philosophy

主要設計理念：

Load Sensing: all consumers are linked by a joint load sensing line. Generated by external loads, the highest LS pressure signal is selected, which is fed to the pump's controller. The controller keeps the pump pressure at [highest LS-signal plus delta p LS].

All controls operate load-independent, i.e. changing loads do not have to be compensated by the operator. In case of excessive power demand, all consumer speeds are reduced proportionally and simultaneously to match the available maximum power. Exceptions (priority functions) are feasible.

負荷傳感：林德LSC、力士樂LUDV、小鬆CLSS係統。選出的執行元件的工作壓力，並將其反饋到泵控製器 ，調節泵的排量，使主閥口兩端壓差保持的設定值。

各執行動作與載荷無關。換句話說，駕駛員不需要頻繁調節手柄以適應執行元件載荷變化。如果執行元件需求流量超出泵能提供的流量，流入各執行元件的流量按主閥開口量大小進行分配。可以很方便地實現流量優先功能。

Negative Flow Control: a permanent purge flow through an orifice behind all consumers is kept constant by monitoring the corresponding pressure drop across the orifice, which is signalled to the pump controller.

負流量控製：主泵輸出流量除了供給各個用戶外，多餘的流量經過一個固定阻尼孔，由此在阻尼孔兩端產生的壓差反饋給泵控製器，泵控製器根據該壓差大小來調節泵的排量

Any combined movements or changing loads will require the operator to trim speeds by joystick adjustment.

缺點：複合動作時，各執行元件相互影響；載荷變化時，執行元件動作亦受影響。需駕駛員再行調節。

Positive Flow Control: similar to NFC technology with a constant purge flow, however, without measuring orifice. By cascading all control pressures through a complex grid of counterbalance valves, the system constantly selects the highest individual control pressure prevailing and passes it to the pump controller. Pump displacement is adjusted by relating any control pressure to defined displacement angles.

正流量控製：邏輯閥篩選出執行元件中的先導控製壓力，並將其反饋給泵的變量控製機構，實現泵排量調節（參考A8VO）中的液壓行程限製控製方式——正常情況下先導壓力決定泵的排量，一旦功率超出事先設定的功率，功率限製器起作用）。