Hydraulic Control System

HYDRAULIC CONTROL SYSTEM











MANUAL VALVE

PRESSURE CONTROL VALVE A, B
Pressure control valve A, B regulate the pressure supplied to each clutch under the control of the pressure control solenoid valve A, B to eliminate shock at the time of shifting.





(1) pressure control valve A - Not operated

PRESSURE CONTROL VALVE A, B





(1) Pressure control valve A - Operation

PRESSURE CONTROL VALVE A, B





(2) Pressure control valve B - Not Operated

PRESSURE CONTROL VALVE A, B





(2) Pressure control valve B - Operation
The main function of this valve controls the rear clutch independently.

SHIFT CONTROL VALVE AND SOLENOID VALVE A, B. C
The line pressure acting upon the shift control valve is controlled by the two shift control solenoid valves (which are switch ON and OFF according to the shifting gear by the transaxle control module command), and the shift control valve is activated according to the shifting gear, thus switching the oil passages.





The relationship of the shifting gear and the ON-OFF switch of shift control solenoid valve "A", "B" and "C" are shown in the table below.

PRESSURE CONTROL VALVE A, B





Comparisons with A4AF2

CHANGED POINTS:
^ N-D valve has been eliminated.
^ PCSV-B has been added for Rear clutch pressure control independently.
^ Mechanical accumulator has been adopted.
^ E/C release control: PCV-A, Switching of SA: CSV E/C

Control Switch Valve & E/C valve





^ Function Switching the pressure of E/C and SA.

Control Switch Valve & E/C valve





^ 2nd. Gear
^ The 2nd. pressure is supplied to SA through CSV.
^ SCSV-C is OFF as well as 1st. gear.

Control Switch Valve & E/C valve





^ 2nd.-3rd. gear
^ SCSV-C maintains OFF as well as 2nd gear.
^ The E/C pressure from shift control valve is intercepted at the E/C valve during up-shifting from 2nd to 3rd gear.
^ SA pressure is supplied from 1-2 shift valve, but the front clutch and SR pressure is also supplied from the 2-3/4-3 shift valve, so the both SR and SA pressure will be set off.

Control Switch Valve & E/C valve





^ 3rd. gear
^ SCSV-C is changed from OFF to ON.
^ The E/C pressure is supplied from 1-2 shift valve at the CSV after finishing the up-shifting from 2nd to 3rd gear.
^ SA pressure is supplied from shift control valve, but the front clutch and SR pressure is also supplied from the 2-3/4-3 shift valve, so the both SR and SA pressure will be set off.

4-2 Skip shift





1. Operating elements
2. Controls
a. R/C engaging duty control
b. E/C releasing duty control
c. Continuous switching to SA
3. Description





a. R/C engaging duty control





b. E/C releasing duty control
4-2 SKIP shift only (SCSV-C ON)
When releasing the E/C clutch pressure, it is controlled by duty of PCSV-A only in case of 4--2 skip shift.
C. Continuous switching to SA From (SCV) to SA through (CSV)

Fail Safe Function
1. TOM fail when drive with 1st or 2nd speed.





Cutting off the E/C pressure by E/C valve.





^ F/C, SR: from 2-3/4-3 shift valve
^ R/C: from PCV-B
^ SA: from 1-2 shin valve

2. TCM when drive with 1st or 2nd speed.





If the hydraulic pressure is supplied to E/C and the F/C, SR pressure is delayed?





^ R/C, E/C, SA: Interlock

NOTE:
^ SA: Servo Apply pressure
^ TIC: Front Clutch pressure
^ TIC: Rear Clutch pressure
^ K/D: Kick Down
^ SCV: Shill Control Valve
^ CSV: Control Switch Valve
^ PCSV: Pressure Control Solenoid Valve
^ SCSV: Shill Control Solenoid Valve
^ PCV: Pressure Control Valve
^ RCEV: Rear Clutch Exhaust Valve