Chrysler laser 1990 Technical Information Manual page 223

WHEN OIL PUMP OPERATES AT LOW SPEED
A part of the fluid discharged from the oil pump
passes through the pilot port and hydraulic pressure
is applied to the rear surface of the plunger, but,
because this hydraulic pressure is weak, the plunger
is pushed toward the left as a result of the force
applied by the plunger's spring, thus opening the
WHEN OIL PUMP OPERATES AT MEDIUM
SPEED (1 ,OOm,OOO RPM)
When the engine speed increases and the pump's
speed also increases, the hydraulic pressure of the
fluid discharged from the pump becomes higher,
overcoming the plunger spring's force, and causing
the plunger to move toward the right. As a result of
this action, one of the variable orifices closes. At the
POWER STEERING - Oil Pump
Plunger
Variable orifice
From oil pump
Variable orifice
Pilot port
Variable orifice
Plunger
Variable &iflce
variable orifices. As a result of this action the fluid
passes through the variable and fixed orifices, and is
sent, by way of the plunger, to the gear box. The
amount of discharge to the gear box at this time is
almost maximum, with the result that an extremely
To oil pump
Fixed orifice
same time, the flow-control valve also is pressed
toward the right, the bypass port opens more, and
the surplus fluid is returned back to the oil pump. In
this way, the amount of discharge flow to the gear
box is reduced, thus resulting in a somewhat
"heavier" steering effort.
Flow-control valve
Fixed yrifice
Bypass 'Lrl
.