Line-Pressure Shifting Control - Subaru SVX 1992 Manual

AUTOMATIC TRANSMISSION AND DIFFERENTIAL [rv122®51 3- 2
5 . LINE-PRESSURE SHIFTING CONTROL
Oil pressure which engages shift clutches (to provide
1st through 4th speeds) is electronically controlled to
meet varying operating conditions .
In other words, line pressure decreases to match the
selected shift position, minimizing shifting shock .
Line pressure (Clutch operating pressure)
I
Shift clutches
I
Transient oil pressure
to operate clutches
( Shift select valve
Shift valve
Manual shift valve `,
C
operated through
'
Manual valve
select lever
Pilot pressure
Signal pressure to
control line pressure)
® Throttle pressure
and shift
Valve
® Accumulator control pressure
(switching
Accumulator
Solenoids 1
.
an
-
d
-
2
Accumulator control
pressure
I
Accumulator control valve
I
Drain
Line pressure optimally r - 1
regulated for clutch operation
I Duty solenoid A I
-------- -------- ----------
__j'(Line-pressure) I
Pressure regulator valve
Throttle pressure (also ® .°' I
I serves as a signal to optimally
c I
1 -° I
I Line pressure
regulate line pressure under
.
1 built up by t
varying operating conditions) '
oil pump
Drain o
I t Pilot pressure t \ o I
1
c
I
I Oil pump Pilot pressure
I r Orifice
I
I
I Suction I
I TCU I
I I
4 I
Oil tank I
~1
Throttle position,)
l L--------------- .-----------------
-
accelerator pedal I
t` ~~ j depressing speed,
etc. I
I
I
I I
L-------J
B3-516
Fig. 62
e Electronic control of clutch oil pressure in summary
a. Solenoids activate through the TCU which receives
various control signals (throttle signal, etc .)
b. Control signals are converted into throttle pressure,
which is transmitted to the pressure regulator valve .
c. The pressure regulator valve optimally regulates line
pressure (built-up by oil pump) in response to throttle
pressure, matching varying operating conditions .
85