Advanced Vehicle Technology Episode 1 Part 10 docx

These valves are variable pressure reduction valves which are actu-ated by the appropriate solenoid valves, electronic pressure regulator valves, traction valves and shift valves and are

Clutch/brakes (CV-A, CV-B, CV-C, CV-D/BV-E,

BV-F and BV-G) (Fig 5.39) The clutch valves

control the engagement and disengagement of the

multiplate clutches and brakes These valves are

variable pressure reduction valves which are

actu-ated by the appropriate solenoid valves, electronic

pressure regulator valves, traction valves and shift

valves and are responsible for producing the

desired clutch pressure variations during each

gear shift phase Clutch valves CV-B, CV-C and

CV-F are influenced by modulation pressure which

resists the partial closure of the clutch valves, hence

it permits relatively high fluid pressure to reach

these multiplate clutches and brake when large

transmission torque is being transmitted

Retaining valves (RV-E and RV-G) (Fig 5.39) In

addition to the electronic pressure regulator valve

which actuates the clutch valves, the retaining

valves RV-E and RV-G modify the opening and

closing phases of the clutch valves in such a way as

to cause a progressive build-up or a rapid collapse

of operating multiplate clutch/brake fluid pressure

during engagement or disengagement respectively

Traction/coasting valve (T/C-V) (Fig 5.39) The

traction coasting valve T/C-V cuts out the

regulat-ing action of the traction valve TV (5±4) and shifts

the traction valve TV (4±5) into the shut-off

posi-tion when required

Traction valve (TV) (4±5) (Fig 5.39) The traction

valve TV (4±5) controls the main system fluid

pres-sure to the multiplate-clutch MPC-B via the

trac-tion valve TV (5±4) and clutch valve CV-B and

hence blocks the fluid pressure reaching the

multi-plate clutch CV-B when there is a upshift from

fourth to fifth gear

Traction valve (TV) (5±4) (Fig 5.39) The traction

valve TV (5±4) is another form of clutch valve, its

function being to supply system pressure to the

multiplate clutch MPC-B via clutch valve CV-B

when there is a downshift from fifth to fourth gear

Converter pressure valve (CPV) (Fig 5.39) The

converter pressure valve `CPV' supplies the torque

converter with a reduced system pressure to match

the driving demands, that is, driving torque under

varying driving conditions, it also serves as a

pres-sure limiting valve to prevent excessive prespres-sure

build-up in the torque converter if the system

pressure should become unduly high The valve in

addition vents the chamber formed on the

drive-plate side of the lock-up clutch when the torque converter pressure control valve is actuated Converter pressure control valve (CPCV) (Fig 5.39) The converter pressure control valve

`CPCV' is actuated by the electronic pressure reg-ulation valve `EPRV-4', its purpose being to pre-vent the converter pressure valve `CPV' from supplying reduced system pressure to the chamber formed between the drive-plate and lock-up clutch and to vent this space As a result the fluid pressure

on the torque converter side of the lock-up clutch is able to clamp the latter to the drive-plate

Converter lock-upclutch valve (CLCV) (Fig 5.39) The converter lock-up clutch valve

`CLCV' is actuated with the converter pressure control valve `CPCV' by the electronic pressure regulation valve `EPRV-4' The converter lock-up clutch valve `CLCV' when actuated changes the direction of input flow at reduced system pressure from the drive-plate to the turbine wheel side of the lock-up clutch Simultaneously the converter pres-sure valve `CPV' is actuated, this shifts the valve so that the space between the drive-plate and lock-up clutch face is vented As a result the lock-up clutch

is forced hard against the drive-plate thus locking out the torque converter function and replacing

it with direct mechanical drive via the lock-up clutch

Lubrication pressure valve (LPV) (Fig 5.39) The lubrication pressure valve `LPV' supplies fluid lubricant at a suitable reduced system pressure to the internal rubbing parts of the transmission gear train

5.10.8 Operating description of the electro/

hydraulic control unit

To simplify the various solenoid valve, clutch and brake engagement sequences for each gear ratio Table 5.6 has been included

Neutral and park position (Fig 5.39) With the selector lever in neutral or park position, fluid is delivered from the oil-pump to the selector position valve `SPV', modulation pressure valve `MOD-V', pressure reduction valves `PRV-1' and `PRV-2', shift valve `SV-1', traction/coasting valve `(T/C)V' and clutch valve `CV-G' Regulating fluid pressure

is supplied to the torque converter `TC' via the converter pressure valve `CPV' and to the lubrica-tion system by way of the lubricalubrica-tion pressure valve

`LPV' At the same time regulated constant fluid 172

`MV1, MV2 and MV3' via the pressure reduction

valve `PRV-1', and the electronic pressure

regulat-ing valves `EPRV-(1±4)' via the pressure reduction

valve `PRV-2' In addition controlling modulation

pressure is relayed to the spring chamber of clutch

valves `CV-B, CV-C and CV-D' and brake valve

`CV-F' via the modulation pressure valve

`MOD-PV' Neutral and parking position has the

follow-ing multiplate clutch solenoid valves and electronic

pressure regulator valves activated:

1 multiplate brake `MPB-G'

2 solenoid valves `MV1 and MV3'

3 electronic pressure regulating valves `EPRV-1

and EPRV-2'

First gear (Fig 5.41) Engagement of first gear is

obtained by applying the one way clutch `OWC' and

multiplate clutch and multiplate brake `MPC-B

and MPB-G' respectively This is achieved in the

following manner:

1 Moving selector position valve `SPV' into D drive

range Fluid pressure from the selector position

valve `SPV' then passes via the traction valves `TV

(4±5) and TV (5±4)' respectively to clutch valve

`CV-B', it therefore permits fluid pressure to

apply the multiplate clutch `MPC-B'

2 Energizing solenoid valves `MV1 and MV2' opens

both valves Solenoid valve `MV1' applies a

reduced constant fluid pressure to the left-hand

side of shift valves `SV-1 and SV-3' Shift valve

`SV-1' shifts over to the right-hand side against

the tension of the return spring blocking the fluid

pressure passage leading to clutch valve `CV-D',

however shift valve `SV-3' cannot move over

since a similar reduced constant pressure is

intro-duced to the spring end of the valve via solenoid

valve `MV2' Solenoid valve `MV2' applies

reduced constant pressure to the left-hand side

of shift valve `SV-2' and the right-hand side of

shift valve `SV-3'; this pushes the shift valve

`SV-2' to the right and so prevents shift valve

`SV-3' also being pushed to the right by fluid

pressure from solenoid valve `MV1' as

pre-viously mentioned

3 Electronic pressure regulator valve `EPRV-1'

supplies a variable regulated fluid pressure to

the modulation pressure valve `MOD-PV', this

pressure being continuously adjusted by the

elec-tronic transmission control unit `ETCU' to suit

the operating conditions Electronic pressure

regulating valve `EPRV-3 supplies a variable

controlling fluid pressure to brake and retaining

fluid pressure to apply the multiplate brake

`MPB-G'

Second gear (Fig 5.42) Engagement of second gear is obtained by applying multiplate clutch

`MPC-B' and the multiplate brakes `MPB-E and MPB-G' This is achieved in the following manner with the selector position valve in the D drive range:

1 Multiplate clutch and brake `MPC-B and MPB-G' respectively applied as for first gear

2 Solenoid valves `MV1 and MV2' are energized, thus opening both valves Fluid pressure from

`MV1' is applied to the left-hand side of both

`SV-1 and SV-3'; however, only valve SV-1 shifts over to the right-hand side At the same time fluid pressure from solenoid valve `MV2' shifts valve `SV-2' over against the return-spring tension and also pressurizes the spring end of shift valve `SV-3' This prevents shift valve

`SV-3' moving over to the right-hand side when fluid pressure from solenoid valve `MV-1' is simultaneously applied at the opposite end

3 The electronic pressure regulating valves

`EPRV-1 and EPRV-3' have their controlling current reduced, thereby causing an increase in line pressure to the modulation valve MOD-PV and to both brake and retaining valves `BV-G and RV-B' respectively Consequently line pres-sure continues to apply the multiplate brake

`MPB-G'

4 The electronic pressure regulating valve `EPRV-2' has its controlling current reduced, thus pro-gressively closing the valve, consequently there will be an increase in fluid pressure acting on the right-hand side of both brake and retaining valves `BV-E and RV-E' respectively As a result the brake valve `BV-E' opens to permit line pres-sure to actuate and apply the multiplate brake

`MPB-E'

Third gear (Fig 5.43) Engagement of third gear is obtained by applying the multiplate clutches

`MPC-B and MPC-D' and the multiplate brake MPB-E

The shift from second to third gear is achieved in the following manner with the selector position valve in the D drive range:

1 Multiplate clutch `MPC-B' and multiplate brake

`MPB-E' are applied as for second gear

2 Solenoid valve `MV2' remains energized thus keeping the valve open as for first and second gear

173

T TC P

S OWC

MPB E

MPC A

MPC B

MPC C

MPB F

MPB G

MPC D

CV-B

CV-C

TV (5-4)

CPV

CLCV

CPCV

to

LUB

LPV NRV

FIQ (torque)

TVP (acceleration)

SS engine/trans.

Transmission program

ETCU GCPS

MV3

PRV-1 SV-1 SV-2 SV-3

1

MPV

SPV

P

EPRV-1

TV (4-5)

MOD-PV

PRV-2

EPRV-2

EPRV-3

EPRV-4

Y NRV

Fig 5.41 Hydraulic/electronic transmission control system ± first gear

TC P T S OWC

MPB E

MPC A

MPC B

MPC C

MPB F

MPB G

RV-E

BV-E

RGV

CV-C

RV-G

BV-G

BV-D

CPV

CLCV

CPCV

LPV

CV-B

TV (5-4)

MPC D

NRV

to

LUB

FIQ (torque)

TVP (acceleration)

SS engine/trans.

Transmission program

ETCU

GCPS

Y

P

SPV 2

MPV

EPRV-4 EPRV-3 EPRV-2

EPRV-1

PRV-2 MOD-PV

TV (4-5)

MV3

PRV-1 SV-1 SV-2 SV-3

Fig 5.42 Hydraulic/electronic transmission control system ± second gear

T TC P

S OWC

MPB E

MPC A

MPC B

MPC C

MPB F

MPB G

MPC D

RGV

BV-D

CV-B

CV-C

Y

(T/C)V

TV (5-4)

CPV

CLCV

CPCV

to

LUB

LPV

PRV NRV

FIQ (torque)

TVP (acceleration)

SS engine/trans.

Transmission program

ETCU GCPS

MV3

PRV-1 SV-1 SV-2 SV-3

1

MPV

SPV

P

EPRV-1

TV (4-5)

MOD-PV

PRV-2

EPRV-2

EPRV-3

EPRV-4 Y

3

NRV

Fig 5.43 Hydraulic/electronic transmission control system ± third gear

T TC P

S OWC

MPB E

MPC A

MPC B

MPC C

MPB F

MPB G

MPC D

RGV

BV-D

CV-B

CV-C

(T/C)V

TV (5-4)

CPV

CLCV

CPCV

LPV

Y

BV-F

to

LUB

PRV NRV

FIQ (torque)

TVP (acceleration)

SS engine/trans.

Transmission program

ETCU GCPS

MV3

PRV-1 SV-1 SV-2 SV-3

1

MPV

SPV

P

EPRV-1

TV (4-5)

MOD-PV

PRV-2

EPRV-2

EPRV-3

EPRV-4 Y

4

Fig 5.44 Hydraulic/electronic transmission control system ± fourth gear

T TC P

S OWC

MPB E

MPC A

MPC B

MPC C

MPB F

MPB G

MPC D

RGV

BV-D

CV-B

CV-C

Y

(T/C)V

TV (5-4)

CPV

CLCV

CPCV

to

LUB

LPV

PRV NRV

FIQ (torque)

TVP (acceleration)

SS engine/trans.

Transmission program

ETCU GCPS

MV3

PRV-1 SV-1 SV-2 SV-3

5

MPV

SPV

P

EPRV-1

TV (4-5)

MOD-PV

PRV-2

EPRV-2

EPRV-3

EPRV-4

Y NRV

Fig 5.45 Hydraulic/electronic transmission control system ± fifth gear

T TC P

S OWC

MPB E

MPC A

MPC B

MPC C

MPB F

MPB G

MPC D

RGV

BV-D

CV-B

CV-C

Y

(T/C)V

TV (5-4)

CPV

CLCV

CPCV

to

Lub

LPV

PRV NRV

FIQ (torque)

TVP (acceleration)

SS engine/trans.

Transmission program

ETCU GCPS

MV3

PRV-1 SV-1 SV-2 SV-3

R

MPV

SPV

P

EPRV-1

TV (4-5)

MOD-PV

EPRV-2

EPRV-3

EPRV-4 Y

PRV-2

NRV

Fig 5.46 Hydraulic/electronic transmission control system ± reverse gear

3 Solenoid valve `MV3' is in the de-energized state,

it therefore blocks line pressure reaching traction/

coasting valve `(T/C)V' via passage `Y-Y'

4 Electronic pressure regulating valves `EPRV-1

and EPRV-2' de-energized, this closes the valves

and increases their respective regulating fluid

pressure as for second gear

5 Electronic pressure regulating valve `EPRV-3'

control current is increased, this causes the

valve to open and the regulating fluid pressure

to collapse The returning spring now moves the

clutch and retaining valves `CV-G and RV-G'

respectively over to the right-hand side Brake

valve `BV-G' now blocks the line pressure

reach-ing the multiplate clutch MPB-G and releases

(exhausts) the line pressure imposed on the

annular shaped brake piston; the multiplate

brake `MPB-G' is therefore disengaged

6 Solenoid valve `MV1' is de-energized, this

per-mits the shift valve `SV-1' to return to the

left-hand side Subsequently line pressure now passes

via the shift valve `SV-1' to the clutch valve `CV-D'

and hence applies the multiplate clutch `MPC-D'

Fourth gear (Fig 5.44) Engagement of fourth

gear is obtained by applying the multiplate clutches

`MPC-B, MPC-C and MPC-D'

The shift from third to fourth gear is achieved in

the following manner with the selector position

valve in the D drive range:

1 Multiplate clutches `MPC-B and MPC-D'

applied as for third gear

2 Solenoid valves `MV1 and MV3' de-energized

and closed as for third gear

3 Electronic pressure regulating valve `EPRV-1'

de-energized and partially closed, whereas

`EPRV-3' remains energized and open, both

valves operating as for third gear

4 Electronic pressure regulating valve `EPRV-2'

now progressively energizes and opens, this

removes the control pressure from brake and

retaining valves `BV-E and RV-E' respectively

Line pressure to brake valve `BV-E' is now

blocked causing the release (exhausting) of fluid

pressure via the brake valve `BV-E' and the

dis-engagement of the multiplate brake `MPB-E'

5 Fluid pressure now passes though to the

multi-plate clutch `MPC-C' via shift valves `SV-1 and

SV-2', and clutch-valve `CV-C' Subsequently,

the multiplate clutch `MPC-C' is applied to

complete the gear shift from third to fourth gear

6 Electronic pressure regulating valve `EPRV-4'

de-energizes and progressively closes Control

pressure now shifts converter pressure control

valve `CPCV' to the left-hand side and converter lock-up clutch `CLCV' to the right-hand side Fluid pressure is thus supplied via the converter lock-up clutch valve `CLCV' to the torque con-verter `TC', whereas fluid pressure reaching the left-hand side of the torque converter lock-up clutch chamber is now blocked by the converter lock-up clutch valve `CLCV' and exhausted by the converter pressure valve `CPV' As a result fluid pressure within the torque converter pushes the lock-up clutch hard against the impeller rotor casing Subsequently the transmission drive, instead of passing via fluid media from the impeller-rotor casing to the turbine-rotor output shaft, is now diverted directly via the lock-up clutch from the impeller-rotor casing to the turbine-rotor output shaft

Fifth gear (Fig 5.45) Engagement of fifth gear is obtained by applying the multiplate clutches

`MPC-C and MPC-D' and the multiplate brake

`MPB-E'

The shift from fourth to fifth gear is achieved in the following manner with the selector position valve `SPV' in the D drive range:

1 Multiplate clutches `MPC-C and MPC-D' applied as for fourth gear

2 Solenoid valve `MV2' de-energized as for fourth gear

3 Solenoid valve `MV3' is energized, this allows fluid pressure via passage `Y-Y' to shift trac-tion/coasting valve `(T/C)V' over to the right-hand side As a result fluid pressure is released (exhausts) from the spring side of the traction valve `TV (5±4)', hence fluid pressure acting on the left-hand end of the valve now enables it to shift to the right-hand side

4 Solenoid valve `MV1' is energized, this pres-surizes the left-hand side of the shift valves `SV-1 and SV-3' However, `SV-1' cannot move over due to the existing fluid pressure acting on the spring end of the valve, whereas `SV-3' is free to shift to the right-hand end Fluid pressure from the clutch valve `CV-E' now passes via shift valve

`SV-3' and traction/coasting valve `(T/C)V' to the traction valve `TV (4±5)' causing the latter

to shift to the right-hand side Consequently traction valve `TV (4±5)' now blocks the main fluid pressure passing through the clutch valve

`CV-B' and simultaneously releases the multi-plate clutch `MPC-B' by exhausting the fluid pressure being applied to it

5 Electronic pressure regulating valve `EPRV-2' de-energized and partially closed Controlled 186