The LS (load sensing) valve detects the load
and controls the pump delivery.
q This valve controls main pump delivery (Q)
according to differential pressure (EPLS)[=
PP – PLS], called the LS differential pressure
(the difference between main pump pressure
PP and control valve outlet port pressure PLS).
q Main pump pressure (PP), pressure (PLS)
(called the LS pressure) coming from the control
valve output, and pressure (PSIG) (called
the LS selector pressure) from the proportional
solenoid valve enter this valve.
q The relationship between the LS differential
pressure between the main pump pressure
(PP) and LS pressure (PLS) (EPLS) [= (PP) –
(PLS)] and the pump delivery (Q) changes as
shown in the diagram according to LS selector
current (ISIG) of the LS-EPC valve.
q As (ISIG) changes from 0 to 1A, setting force
of the spring also changes. As the result, the
specified median of the pump delivery selector
point changes in the range of 1.18 to 2.65 MPa