Komatsu ecot3 PC300LC-8 Shop Manual page 277

10 Structure, function and maintenance standard
1) LS control function
q Depending on the operation condition of
the actuator, this function changes the
pressure output from the LS-EPC valve to
LS valve to change the change point (LS
set differential pressure (DLS)) of the
pump discharge in the LS valve.
By this operation, the start-up time of the
q
pump discharge is optimized and the com-
posite operation and fine control perfor-
mance is improved.
2) Cut-off function
This function increases PC-EPC current
q
(J) to reduce the flow rate in the relief
state, improving fuel consumption.
Operating condition for turning on cut-off function
When the average value of the front and rear pressure
sensors is above 27.9 MPa {285 kg/cm
maximizing function off.
The cut-off function does not work, however, while the
machine is travelling in P mode, swing lock switch is in
the "ON" position.
PC300, 350-8
3)
Operating condition for turning on
2-stage relief function
• During travel
• When swing lock switch is turned to
• When boom is lowered
• When power maximizing function is
• When L mode is operated
2
} with the power
2-stage relief function
q The relief pressure in the normal work is
34.8 MPa {355 kg/cm
relief function is turned on, however, the
relief pressure rises to about 37.2 MPa
2
{380 kg/cm }. By this operation, the
hydraulic force is increased further.
the ON position
turned on
SEN01998-05
2
}. If the 2-stage
Relief pressure
34.8 MPa
2
{355 kg/cm }
O
37.2 MPa
2
{380 kg/cm }
19