Komatsu ecot3 PC300LC-8 Shop Manual page 286

SEN01998-05
1) Pump control function during travel
q If the machine travels in a work mode
other than P mode, the work mode and
the engine speed are kept as they are and
the pump absorption torque is increased.
q For details, see "Engine and pump com-
posite control function."
28
10 Structure, function and maintenance standard
2) Travel speed change function
1] Manual change with travel speed switch
If one of Lo, Mi and Hi is selected with the
travel speed switch, the pump controller
controls the pump capacity and motor
capacity at each gear speed as shown
below to change the travel speed.
Travel speed switch
Pump capacity (%)
Motor capacity
Travel speed (km/h)
2] Automatic change by engine speed
If the fuel control dial is used to set the
engine speed to less than 1,200 rpm, the
travel speed changes to Lo when the
machine is travelling in Mi or Hi, and the
travel speed will not change to Mi or Hi.
3] Automatic change by pump discharge
pressure
When traveling with the travel speed
s w i t c h s e t t o H i o r M i , i f t h e l o a d
increases, such as when travelling uphill,
and the travel pressure goes above 32.3
MPa {330 kg/cm
the travel motor capacity will automatically
change to low speed (equivalent to Lo).
(The travel speed switch will stay at Hi or
Mi.)
If the load decreases, such as when trav-
elling on level ground or travelling down-
hill, and the travel pressure goes below
18.6 MPa {190 kg/cm
sec, the travel motor capacity will auto-
matically change and will return to Hi or
Mi.
Lo Mi
(Low (Medium (High
speed) speed) speed)
90 82
Max. Min.
3.2 4.5
2
} for more than 0.5 sec,
2
} for more than 0.5
PC300, 350-8
Hi
100
Min.
5.5