attn 0205 aj

A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ

Describe Functions of CVT

CHA0365

1

OBJECTIVE

PERFORMANCE: • Be able to describe the construction of the CVT (Continuously

Variable Transmission). • Be able to describe the functions of the component parts of the CVT.

RESOURCES: The following resources have been prepared for this module.

• NISSAN vehicle with CVT • ESM


• Describe the construction of the CVT. SKILL CHECK • Describe the the functions of the component parts of the CVT.

2


3

CONTENTS

1. FEATURES 1) Outline 2) Driving Force 3) Improvement of Fuel Consumption

2. MECHANICAL OUTLINE 1) Cross-Sectional View 2) System Configuration 3) Torque Converter 4) Forward/Reverse Gear Switching

Mechanism 5) Final Drive and Differential Gear 6) Fluid

3. BELT AND PULLEY 1) Cross-Sectional View 2) Mechanism 3) Steel Belt 4) Pulley

4. ELECTRONIC CONTROL

1) Control System Outline 2) Control System Diagram 3) Circuit Diagram 4) Control Items and Input/Output Signal List 5) Line Pressure and Secondary Pressure

Control 6) Shift Control 7) Lockup and Select Control 8) EEPROM Erasing 9) CVT Unit Removal and Installation

TARGET

Ability to describe the construction of the CVT

Ability to describe the

functions of the component parts of the CVT


4

CONTENTS

5. HYDRAULIC CONTROL SYSTEM 1) Outline 2) Function of Control Valve 3) Oil Pump

Here’s what you do . . . . (1) SKILL CHECK

TARGET

If you feel confident about your knowledge and skills of these tasks, you can proceed to the next module. Ask your course instructor for guidance.


1. FEATURES

1) Outline The CVT has achieved both “high driving performance” and “low fuel consumption” with a combination of the “torque converter” and the “continuously variable transmission with steel belt and pulley”. It automatically selects the optimum gear ratio continuously from the low gear to the overdrive gear according to the driving condition. Smooth driving without shocks during shift changing and a high response to the accelerator pedal as desired by a driver can be achieved. The CVT-M6 has the 6-speed gear ratios that provide the pleasure of driving with the manual shift feeling.

CHA0394

For 3.0 – 3.5LXtronic CVT Xtronic CVT-M6

Hyper CVT Hyper CVT-M6

N-CVT

For FF models

Genera

tion c

hange

1992

1997

2003

Extroid CVT

For 1.0 – 1.3L

For 1.0 – 2.0L

For 1.4 – 3.5L

For FR models NISSAN introduced the continuously variable transmission as N-CVT using a magnetic clutch. To expand the CVT equipped models, Hyper CVT is equipped with a torque converter covering 2.0-liter zone engines. Currently, Xtronic CVT expands the adopted models by covering 3.5-liter zone engines. Transmitting the high torque produced by a 3.5-liter engine requires the application of greater pressure to the pulleys that squeeze the steel belt. A belt with sufficiently high durability was developed to withstand the additional pulley pressure (RE0F09A type).

CAUTION:

Never tow the vehicle with the driving wheels on the ground due to the potential to damage the CVT.

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2) Driving Force

CHA0366

CVT has no loss of driving force without shift shock inside the hatched area.

CVT

CVT

4th speed

4th speed

3rd speed

3rd speed

2nd speed

2nd speed

1st speed

1st speed

A/T

A/T

Full opening of accelerator throttle

Vehicle speed

Vehicle speed

En

gin

e s

pe

ed

Dri

vin

g f

orc

e

The shift diagram on the right during wide open throttle shows that a conventional AT indicates changing steps of engine speed at a shift point while CVT increases the vehicle speed without steps. The driving force diagram on the right shows the maximum driving force during wide open throttle. The conventional A/T shows steps in the driving force because of the non-continuously variable transmission. In contrast, the CVT allows acceleration while maintaining the high engine output. The driving force varies smoothly. The CVT does not have loss of the driving force equivalent to the hatched area. Thus, smooth and shock-less driving is realized.

3) Improvement of Fuel Consumption

• Driving near the best fuel consumption rate has been achieved, resulting in improvement of the actual fuel consumption as shown in the diagram on the right.

CHA0367

En

gin

e t

orq

ue

Best fuel consumption rate

Operation range of CVT

Engine speed

Operation range during constant driving

Operation range of A/T

• The lockup vehicle speed of the torque converter has been lowered (the lockup range is widened). The slippage loss has been reduced, and the fuel cut range during driving with the accelerator pedal released has been widened.

These efforts have contributed to the improvement of fuel consumption.

The features of the CVT are introduced in the video program provided here.

Watch a video

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2. MECHANICAL OUTLINE

1) Cross-Sectional View CHA0368

1. Converter housing 2. Oil pump 3. Forward clutch 4. Reverse brake 5. Planetary carrier

6. Primary pulley 7. Steel belt 8. Sun gear 9. Side cover

11. Secondary pulley 12. Final gear 13. Differential case14. Idler gear15. Reduction gear

16. Taper roller bearing17. Output gear18. Parking gear 19. Input shaft20. Torque converter

AWD model Differential

10. Internal gear

RE0F09A type

Excerpt from ESM/2006 Z50 for North America

7


2) System Configuration

CHA0369

Control valve

Wheel Final gearDifferentialgear

Parkingsystem

Belt andPulley

Forward andreversechange

Torqueconverter

Oil pump

Oil pressure control

Electrical controlPrimaryspeedsensorPNP

switch

Secondaryspeedsensor

Engine

Transaxle

Crankshaft position sensor (POS) and Camshaft position sensor (PHASE)

Control device

Acceleratorpedalpositionsensor

CAN communication

TCM

ECM

Unifiedmeter andA/C amp

ABS actuatorand electricunit(control unit)

AWD controlunit

Mechanical systemOil system

Electrical system

CAN communication

Second position indicator (Without manual mode)

Manual modeindicator(With manual mode)

Second position switch (Without manual mode)

Manual mode switch(With manual mode)

Wheel sensor

Stop lamp switch

CVT position indicator

CVT indicator lamp

Xtronic CVT


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3) Torque Converter

The torque converter increases the engine torque and transmits the torque to the transaxle, which is explained in the A/T Mechanical Fundamentals ATTN0201AJ module. It includes the lockup mechanism.

4) Forward/Reverse Gear Switching Mechanism

• The single planetary gear type forward/reverse switching mechanism is mounted between the torque converter and the primary pulley.

• The power from the torque converter is transmitted to the input shaft. The wet type multiple disc clutch is hydraulically operated to switch the forward/reverse gear.

CHA0370

Reverse brake (release) Reverse brake (release) Reverse brake (engagement)Planet carrier

Planet carrier (idling)

Planet carrier (idling) Planet carrier (fixed)

Internal gearInternal gear (clockwise)

Internal gear (clockwise) Internal gear (idling)

Forward clutch (release)

Forward clutch (release)

Forward clutch (engagement)

Sun gear

Sun gear (stop)

Sun gear (counter-clockwise)

Sun gear (counter-clockwise)

Sun gear (clockwise)

Sun gear

Primary pulley Input shaft

P and N ranges D and L ranges R range

Internal gear (clockwise)

9


5) Final Drive and Differential Gear

• The reduction gear consists of 2 stages: the 1st reduction area (pair with the output gear and the idler gear) and the 2nd reduction area (pair with the reduction gear and the final drive gear). Both gears use the helical gears.

6) Fluid

CHA0371

Type without viscous LSD (RE0F06A type) Type with viscous LSD (RE0F06V type)

Reduction gear

Final drive gear

Final drive gearOutput gear

2nd reduction area

1st reduction area

Idler gear

Differential case

Differential case

Viscous coupling

For optimum operation and lubrication of the CVT mechanism with large engine torque capacity, NISSAN CVT fluid NS-2 is specially designed.

• Use only Genuine NISSAN CVT fluid NS-2. Do not mix with other fluid. • Using CVT fluid other than Genuine NISSAN CVT fluid NS-2 will deteriorate

drivability and durability, and may damage the CVT, which is not covered by the warranty.

CVT FLUID REPLACEMENT Normal usage: It is not necessary to replace fluid throughout the vehicle life. Towing trailers usage: You should check for CVT fluid deterioration every 96,000 km using CONSULT-II work support “CVTF DETERIORATION DATE”.

You should replace the fluid if the value is more than 210,000. The value has no unit and is just the factor calculated by various driving factors such as mileage, vehicle speed, engine speed, engine load, fluid temperature, number of warming up cycles, etc. You should reset the value after replacement of the CVT fluid.

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3. BELT AND PULLEY

1) Cross-Sectional View

CHA0372

Steel belt

Primary pulley (pulley at input shaft side)

Fixed pulley

Fixed pulley

Secondary pulley (pulley at output shaft side)

Movable pulley

Movable pulley

Secondary pulley chamber

Primary pulley chamber

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2) Mechanism

The unit consists of a pair of pulleys that allows free variation of the groove width in the axial direction and steel belts that are guided by continuous steel pieces and multi-layered steel rings on both sides. Shifting from the low gear (1st) to the high gear (overdrive) varies continuously without steps according to the winding diameter of the steel belt and the pulley. This groove width is controlled by the hydraulic pressure of the primary pulley and the secondary pulley.

3) Steel Belt

The belt consists of hundreds of steel pieces and two multi-layered steel rings. The feature of this steel belt is that the force is transmitted by compression of the steel pieces, instead of a rubber belt that transmits the force with tension.

CHA0373

Steel piecesSteel rings

22˚

12


4) Pulley

Both the primary and the secondary pulleys consist of the fixed pulleys with an inclined surface of 11° and the movable pulley. At the back of the movable pulley, the hydraulic chamber (primary and secondary chamber for each) is installed. The movable pulley slides on the shaft with the ball spine to change the pulley groove width. Input signals of the engine load (accelerator throttle opening), the primary pulley revolution and the secondary pulley revolution (vehicle speed) change the operation pressure of the primary and secondary pulleys to control the pulley groove width.

CHA0374

Primary pulley

Primary pulley

Fixed pulley

11˚

Fixed pulleyOverdrive gear condition Gear ratio r2/r1

1st gear condition Gear ratio r2/r1

Wide

Wide

Narrow

r2

r2

Pulley groove width

Narrow

Secondary pulley

Movable pulley

Secondary pulley

Movable pulley

Secondary pulley

Secondary pulley

r1

r1

13


4. ELECTRONIC CONTROL

1) Control System Outline

The major functions of the Transmission Control Module (TCM) are as follows.

• Receive input signals sent from various switches and sensors. • Determine the required line pressure, shifting point and lockup operation. • Send required output signals to the step motor and the respective solenoids. The CVT senses vehicle operation conditions through various sensors. It always controls the optimum shift position and reduces shifting and lockup shocks.

Sensors (or signals) TCM Actuators

PNP switch

Accelerator pedal position signal Closed throttle position signal CVT fluid temperature sensor Vehicle speed signal Manual mode signal Engine speed signal

Second position signal* Stop lamp switch signal Primary speed sensor Primary pressure sensor Secondary speed sensor Secondary pressure sensor

Shift control

Line pressure control Primary pressure control Secondary pressure control Lockup control Engine brake control Vehicle speed control

Fail-safe control Self-diagnosis CONSULT-ll communication lineDuet-EA control CAN system On board diagnosis

Step motor

Torque converter clutch solenoid valveLockup select solenoid valve Line pressure solenoid valve Secondary pressure solenoid valve Manual mode indicator Second position indicator*

CVT position indicator CVT indicator lamp Starter relay

*: Without manual mode.

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2) Control System Diagram

CHA0375

CVTassembly

Line pressure solenoid valve

Secondary pressure solenoid valve

Torque converter clutch solenoid valve

Lockup select solenoid valve

Secondary speed sensor

Primary speed sensor

ECMCAN communication

ABS actuatorand electric unit

(control unit)

Unified meterand A/C amp

CVT fluid temperature sensor

Secondary pressure sensor

Primary pressure sensor

Secondarypulley

Primarypulley

Belt

Shift link

Step motor

PNP switch

TCM

Manual mode indicator(With manual mode)

Second position indicator(Without manual mode)

Second position switch(Without manual mode)

Manual mode switch(With manual mode)

CVT indicator lamp

Stop lamp switch

CVT position indicator

Wheel sensor

Accelerator pedalposition sensor

Crankshaft position sensor (POS) and Camshaft positionsensor (PHASE)


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3) Circuit Diagram


CHA0376

16


4) Control Items and Input/Output Signal List

CHA0377

Control item

Input

Output

*1: Input by CAN communication. *2: If these input and output signals are different, the TCM triggers the fail-safe function. *3: Without manual mode.

Fluid pressure control

X

X

X

X

X

X

X

X

X

X

X

X

X

X X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

Step motor

TCC solenoid valve




PNP switch

Accelerator pedal position signal (*1)

Closed throttle position signal (*1)

Engine speed signal (*1)

CVT fluid temperature sensor

Manual mode signal (*1) (*3)

Second position signal (*1)

Stop lamp switch signal (*1)

Primary speed sensor

Secondary speed sensor

Primary pressure sensor

Secondary pressure sensor

TCM power supply voltage signal

X

X

X

X

X

X

X

X

X

X

XX

X

X

X

X

X

X

Select control

Shift control

Lockup control

CAN com-munication

control

Fail-safe function

(*2)


CAN COMMUNICATION To control the CVT to be optimum for the driving condition, TCM receives various information through the CAN (Controller Area Network) communication. The information received is common to engine control, ABS, combination meter, etc.

5) Line Pressure and Secondary Pressure Control

• When the engine drive force signal is sent from the ECM to the TCM, the TCM precisely

controls the line pressure solenoid valve and secondary pressure solenoid valve to reduce the friction and to improve the fuel consumption.

• This line pressure solenoid controls the pressure regulator valve as the signal pressure and adjusts the pressure of the operating oil discharged by the oil pump to the line pressure that is most appropriate to the driving state. Secondary pressure is controlled by decreasing the line pressure.

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CHA0378

Pressure regulator valve TCM

Engine speed

Accelerator pedal position

Primary pulley speed

Secondary pulley speed

Line pressuresolenoid valve

Line pressure

Oilpump

<Main input signal>

Oil systemElectrical system

Secondaryvalve

Secondarypressuresolenoid valve

Secondary pressure

NORMAL CONTROL Optimize the line pressure and secondary pressure, depending on the driving conditions, on the basis of such conditions as the throttle position, the engine speed, the primary pulley (input) revolution speed, the secondary pulley (output) revolution speed, the brake signal, the PNP switch signal, the lockup signal, the voltage, the target gear ratio, the fluid temperature and the fluid pressure.

FEEDBACK CONTROL OF SECONDARY PRESSURE When controlling the normal fluid pressure and the selecting fluid pressure, the secondary pressure can be set more accurately by the feedback control detecting the pressure of the secondary fluid pressure.

PRESSURE CONTROL SOLENOID VALVE Xtronic CVT uses a linear solenoid valve to control the line pressure and secondary pressure. A linear solenoid valve controls the pressure proportionally to the applied

CHA0518

Normal high pressure

Normal low pressure

0

0

Current

Current

electric current volume. Thus, these solenoid valve circuits do not have a parallel dropping resistor circuit. A linear solenoid valve has two types: one is normal high that is the maximum pressure when the current is zero, and the another is normal low that is zero pressure when the current is zero. The line pressure and secondary pressure solenoids are the normal high type.

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6) Shift Control

In order to select the gear ratio that can obtain the driving force in accordance with driver's intention and the vehicle condition, TCM monitors the driving conditions, such as the vehicle speed and the throttle position to determine the gear change steps for the optimum gear ratio. Then, it sends a command to the step motor and controls the inflow/outflow of the line pressure to determine the position of the movable pulleys of the primary and secondary pulleys and then controls the gear ratio.

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CHA0379

Oil system

Electrical system

TCM

PNP switch

<Main input signal>




Second position switch

Manual mode switch

Stepmotor

Line pressure

Shift control valve

Primary pulley

Mechanical system


The step motor controls the shift control valve and primary pulley using a unique linkage. If you are interested in learning more about this, see the textbook provided here.

Textbook


D POSITION Shifts over all of the ranges of gear ratios from the lowest to the highest.

CHA0381

Prim

ary

pulle

y sp

eed

Gea

r ra

tio :

low

est

Gear ratio : highest

Vehicle speed

Shift area

S POSITION Use this position for improved engine braking.

CHA0382

Prim

ary

pulle

y sp

eed

Gea

r ra

tio :

low

est

Gear ratio : h

ighest

Vehicle speed

Shift area

L POSITION By limiting the gear range to the lowest position, the strong driving force and the engine brake can be secured. M POSITION When the selector lever is put in the manual shift gate, the fixed changing gear line is set. By moving the selector lever to the + side or - side, the manual mode switch is changed over, and a shift change like M/T becomes possible following the changing gear set line step by step. If the vehicle speed is lower than the intended gear ratio, additional upshift is inhibited by the CVT control module to prevent engine stall. When the vehicle stops, the system controls the gear setting to the 1st speed. If the vehicle speed is higher than the intended gear ratio, additional downshift is inhibited to prevent excessive engine revolution. At full acceleration, automatic upshift occurs without manual shifting when exceeding the specified engine revolution.

CHA0383

Prim

ary

pulle

y sp

eed

Vehicle speed

1st

2nd

3rd 4t

h5th

6th

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DOWNHILL ENGINE BRAKE CONTROL (AUTO ENGINE BRAKE CONTROL)

When a downhill slope is detected with the accelerator pedal released, the engine brake will be strengthened by downshifting so as not to accelerate the vehicle unnecessarily.

Engine brake cancel If a customer strongly requires the cancellation of the engine brake, it is possible to cancel the engine brake. But from the viewpoint of the safety, you should not cancel the engine brake. It is a safety function. To cancel the engine brake, use CONSULT-II work support ENGINE BRAKE ADJ. 0: Normal setting with

engine brake.

OFF: Engine brake is deactivated.

+1, -1, -2: Menu will appear but is not available. Do not set to these values, otherwise irregular drivability may occur. CHA0393

ADJ MONITOR

ENGINE BRAKE ADJ.

MODE BACK

UP DOWN

LIGHT COPY

0

+10-1 -2

OFF

ENGINE BRAKE LEVEL

UP or DOWN

Choose only 0 or OFF

ACCELERATION CONTROL According to vehicle speed and a change of the accelerator pedal angle, a driver's request for acceleration and the driving situation are judged. This function assists with improvement in the acceleration feeling by making the engine speed proportionate to the vehicle speed. Also, a shift map that can gain a larger driving force is available for compatibility of drivability and low fuel consumption. PNP SWITCH A PNP switch is installed on the control valve of Xtronic CVT. The PNP switch consists of 5 digital logic switches working in combination as shown below.

SW1 SW2 SW3 SW4 SW3 MONP OFF OFF OFF OFF OFF R ON OFF OFF ON OFF N ON ON OFF OFF OFF D ON ON ON ON ON

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7) Lockup and Select Control

• The torque converter clutch piston in the torque converter is engaged to eliminate torque converter slip to increase power transmission efficiency.

• The torque converter clutch control valve operation is controlled by the torque converter clutch solenoid valve, which is controlled by a signal from TCM. The torque converter clutch control valve engages or releases the torque converter clutch piston.

• When shifting between N (P) ↔ D (R), the torque converter clutch solenoid controls the engagement power of the forward clutch and reverse brake.

• The lockup applied gear range was expanded by locking up the torque converter at a lower vehicle speed than that for conventional A/T models.

TORQUE CONVERTER CLUTCH AND SELECT CONTROL VALVE CONTROL Lockup and Select Control System Diagram

CHA0384

Thr

ottle

ope

ning

“CVT” lockup area

“A/T” lockup area

Vehicle speed (km/h)

100%

0%50 100

CHA0385

Line pressure

Select control valve

Torque converter clutch control valve

Select switch valve Torque converter clutch solenoid valve

Lockup and select solenoid valve

Manual valveForward clutch

Reverse brake

Torque converter

regulator valveTCM

<Main input signal>

Engine speed




CVT fluid temperature

PNP switchTorque converter lockup ON

Torque converter lockup OFF

Oil systemElectrical system

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LOCKUP RELEASED In the lockup released state, the torque converter clutch control valve is set into the unlocked state by the torque converter clutch solenoid and the lockup apply pressure is drained. In this way, the torque converter clutch piston is not coupled.

LOCKUP APPLIED In the lockup applied state, the torque converter clutch control valve is set into the locked state by the torque converter clutch solenoid and lockup apply pressure is generated. In this manner, the torque converter clutch piston is pressed and coupled.

SELECT CONTROL When shifting between N (P) ↔D (R), optimize the operating pressure on the basis of the throttle position, the engine speed and the secondary pulley (output) revolution speed to lessen the shift shock.


8) EEPROM Erasing

When replacing a CVT, the TCM must be “matched” with the new transmission. The EEPROM of TCM reads the connected CVT unit data just the 1st time (default state) and keeps it. If only the CVT unit is replaced, the EEPROM of TCM needs to be erased and needs to read the new CVT unit data.

EEPROM ERASING PATTERNS CVT assembly TCM Erasing EEPROM in TCM Remarks

Replaced Replaced Not required Not required because the EEPROM in the TCM is in the default state. (CVT assembly must replaced first.)

Not replaced Replaced Not required Not required because EEPROM is in the TCM default state.

Replaced Not replaced Required Required because data has been written in the EEPROM in the TCM and

because the TCM cannot write data from the ROM assembly in the transmission.


The EEPROM erasing method is explained in the video program provided here.

Watch a video

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9) CVT Unit Removal and Installation

The CVT torque converter has studs instead of welded nuts in order to shorten the entire length of the engine and CVT unit. When you install the CVT to the engine, initially you should put on a guide tool to the converter to align the studs to the drive plate holes. Otherwise, the drive plate might be damaged by a stud. The drive plate has 4 small holes for converter tightening and 2 big holes as a guide tool. The drive plate guide hole should be at the bottom when you install the CVT to the engine.

CHA0386

CHA0387

Drive plate location guide (31197 CA000)

Excerpt from Z50 GOM new model training

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25

PARTS REPLACEMENT As of the end of 2005, NISSAN does not recommend reassembly of any of the CVT components for the following reasons.

• CVT unit will not operate properly if there is any contamination in it. Thus, a sufficiently

clean room is necessary for reassembly, which is impossible for a normal workshop. • Assembling the bearing on the pulley shaft needs a special assembling machine. • Assembling the belt on the pulley needs another special assembling machine. For the above reasons, only the outside parts are replaceable, as listed below.

• CVT fluid cooler valve • Differential side oil seal


5. HYDRAULIC CONTROL SYSTEM

1) Outline

The hydraulic control system consists of the oil pump, the hydraulic control valve unit and the actuators such as torque converter, pulleys, clutches and brakes. The oil pump is directly operated by the engine, and the generated hydraulic pressure is transmitted to the control valve unit. The control valve unit controls and delivers the hydraulic pressure to the actuators by means of the transmission control module signals.

The relationship of each component is shown below.

CHA0388

Lubrication & cooling system

Forward clutch

Reverse brake

Torque converterlockup ON

Torque converterlockup OFF

Stepmotor

Shift controlvalve

Control valve

Secondaryvalve

Primarypulley

Secondarypulley

Manualvalve

Torque converterclutch control

valve

Input signal system

Primarypulley speed

Secondarypulley speed

Enginespeed

Throttleposition

CVT fluid temperature

PNP switch

Oil system

Electrical systemMechanical system

TCM

Secondarypressure

solenoid valve

Line pressuresolenoid

valve


Torque converterclutch solenoid

valve

Oil pump

Pressureregulator valve

Clutchregulator valve

Torqueconverter

regulator valve

Select switch valve



26


2) Function of Control Valve

CHA0389

Torque converter regulator valve

Pressure regulator valve

TCC control valve

TCC solenoid valve

Shift control valve

Secondary valve

Clutch regulator valve



Step moto

27

r

Manual valve


Select switch valve & select switch solenoid


Optimizes the supply pressure for the torque converter depending on driving conditions.

Name

Optimizes the discharge pressure from the oil pump depending on driving conditions.

Activates or deactivates the lockup.

Locks up smoothly by opening lockup operation excessively.

Controls flow-in/out of line pressure from the primary pulley depending on the stroke difference between the stepping motor and the primary pulley.

Controls the TCC control valve or select control valve.

Controls the line pressure from the secondary pulley depending on operating conditions.

Adjusts the clutch operating pressure depending on operating conditions.

Controls the secondary valve.

Controls the line pressure control valve.

Controls the pulley ratio.

Transmits the clutch operating pressure to each circuit in accordance with the selected position.

Engages forward clutch, reverse brake smoothly depending on select operation.

Switches torque converter clutch solenoid valve control pressure use to torque converter clutch control valve or select control valve.

Controls the select switch valve.

Function


3) Oil Pump

The trochaic type oil pump with the flow control valve that is directly operated by the engine is used to obtain sufficient discharge from the pump in the low engine speed range and to optimize discharge from the pump in the high engine speed range. Fluid pressure discharged from the oil pump is sent to the control valve. It is used for hydraulic fluid and lubrication oil of the primary and secondary pulleys, brakes and clutches.

There is an extra CVT fluid cooler that is adopted for the model Z50 Xtronic CVT. If you are interested in learning more about this, see the textbook provided here.

Textbook


Here’s what you do . . . . (1)

1. Some features of the CVT are described below. Put a check ” ” in the box that has an appropriate statement.

� Smooth driving without shock in shift change in response to the accelerator pedal

action as desired can be achieved.

� CVT allows acceleration while maintaining the high engine output. This feature

eliminates loss of driving force when shifting.

� Driving in the good fuel consumption range can be achieved, resulting in improvement

of the actual fuel consumption.

� The same as a conventional A/T vehicle, the CVT equipped vehicle must not be towed

with the driving wheels on the ground due to the potential to damage the CVT. 2. Mechanisms of the CVT are described below. Put a check ” ” in the box that has an

appropriate statement.

� The lockup vehicle speed has been lowered, so the slippage loss of the torque

converter has been reduced.

� The forward/reverse switching mechanism consists of a planetary gear and a wet type

multiple disc clutch that is hydraulically operated like a conventional A/T.

� The primary pulley and secondary pulley rotate in the same direction, so the idler gear

is adopted to transmit the power to the final drive.

� When you install the CVT to the engine, initially you should put on a guide tool to the

converter to align the studs to the drive plate holes. Otherwise, the drive plate might be damaged.

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3. Fluid of the CVT is described below. Put a check ” ” in the box that has an appropriate statement.

� For optimum operation and lubrication of the CVT mechanism with the large engine

torque capacity, NISSAN CVT fluid NS-2 is specially designed.

� Using CVT fluid other than Genuine NISSAN CVT fluid NS-2 will deteriorate drivability

and durability, and may damage the CVT, which is not covered by the warranty.

� If the vehicle is used under a heavy load, such as towing a trailer, you should check for

CVT fluid deterioration every 96,000 km using CONSULT-II WORK SUPPORT “CVTF DETERIORATION DATE”.

� You should replace the fluid if the CVT fluid deterioration value is more than 210,000.

And you should delete the value with CONSULT-II after changing the CVT fluid.

4. When replacing a CVT assembly, the TCM must be “matched” with the new transmission. Erasing EEPROM of TCM operation is required in some replacement patterns. Choose the specified pattern from the three patterns shown below.

CVT assembly TCM

� (1) Replaced Replaced

� (2) Not replaced Replaced

� (3) Replaced Not replaced

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5. Choose sensors and switches that TCM uses to control the CVT including CAN communication. Put a check ” ” in the box.

� PNP switch � Manual mode switch or second position switch

� Accelerator pedal position sensor � Primary speed sensor

� Closed throttle position switch � Secondary speed sensor

� Engine speed signal � Primary pressure sensor

� CVT fluid temperature sensor � Secondary pressure sensor

� Vehicle speed sensor � Third pressure sensor

� Stop lamp switch

� Parking brake switch

6. The engine brake function can be canceled using CONSULT-II “work support” mode. You can select the following items shown below on the “ENGINE BRAKE ADJ” screen. Put a check ” ” in the box that has an appropriate statement.

� Mode of +1, 0, -1, -2 and OFF can be selected.

� Mode of 0 and OFF can be selected.

� Mode of +1, -1 and -2 can be selected.

7. The line pressure control solenoid valve is controlled by TCM using two circuits at the conventional AT and Hyper CVT, one is directly connected and another is connected with a dropping resistor.

� The line pressure control solenoid valve is controlled by two circuits at the Xtronic CVT,

the as same as the conventional AT and Hyper CVT.

� The line pressure control solenoid valve is controlled by one circuit without a dropping

resistor at the Xtronic CVT. This is because a linear solenoid valve is adopted for the line pressure control solenoid valve.

Self-check

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At this point, if you feel confident about your knowledge and skills of these tasks, you can proceed to the next page for the skill check for this module.

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Describe Functions of CVT

SKILL CHECK

• Answer the following questions.

• Complete the skill check within 20 minutes. Tell your course instructor when you are ready to start. Your course instructor will time you accordingly.

Put a check ” ” in the box that has an appropriate statement. 1. In the same manner as the conventional A/T vehicle, the CVT equipped

vehicle must not be towed with the driving wheels on the ground due to the potential to damage the CVT.

� Because the torque converter clutch will be engaged to the engine.

� Because the CVT will not be lubricated without the engine running.

2. When you install the CVT to the engine, initially you should put on a guide

tool to the converter.

� To align the studs of the converter to the drive plate holes.

� To align the weld nuts of the converter to the drive plate holes.

3. CVT fluid must be Genuine NISSAN CVT fluid NS-2

� Other fluid may damage the CVT, which is not covered by the warranty.

� Other fluid will deteriorate drivability and durability, which is covered by the

warranty.

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4. CVT fluid deterioration can be checked using CONSULT-II work support

“CVTF DETERIORATION DATE”.

� You should check it every 96,000 km, even when the vehicle is used normally.

� You should check it every 96,000 km, if the vehicle is used under a heavy

load, such as towing a trailer. 5. Erasing EEPROM of TCM operation is required in some replacement patterns.

Choose the specified pattern from the three patterns shown below.

CVT assembly TCM

� (1) Replaced Replaced

� (2) Not replaced Replaced

� (3) Replaced Not replaced

6. To erase EEPROM of TCM, which function of CONSULT-II is required?

� “SELF-DIAG RESULTS” mode for “TRANSMISSION”

� “WORK SUPPORT” mode for “TRANSMISSION”

7. The engine brake function can be adjusted using the CONSULT-II “WORK

SUPPORT” mode. You can select 0 and OFF on the “ENGINE BRAKE ADJ” screen. But the mode of +1, -1 and -2 cannot be selected.

� If the +1 or -1 or -2 is selected, it needs extra setting by CONSULT-II.

� If the +1 or -1 or -2 is selected, it might cause irregular drivability.

8. The TCM precisely controls the line pressure solenoid valve and the

secondary pressure solenoid valve to the line pressure and the secondary pressure that are the most appropriate for the driving state.

� Secondary pressure is controlled by decreasing the line pressure.

� Secondary pressure is controlled by decreasing the pressure of the operating

fluid generated by the oil pump directly.


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9. When a downhill slope is detected with the accelerator pedal released, the

engine brake will be strengthened.

� By engaging the lockup clutch so as not to accelerate the vehicle.

� By downshifting so as not to accelerate the vehicle.

10. To control the gear ratio, the diameters (widths) of the primary and secondary

pulleys are adjusted using their movable pulleys by the following method.

� TCM sends the command to the step motor and controls the inflow/outflow of

the line pressure.

� TCM sends the command to the shift solenoids A & B and controls the

inflow/outflow of the line pressure.


COURSE INSTRUCTOR’S SIGNATURE

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Technician

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