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Transcript of 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
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
• Describe the construction of the CVT. SKILL CHECK • Describe the the functions of the component parts of the CVT.
2
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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.
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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.
5
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
6
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
Excerpt from ESM/2006 Z50 for North America
8
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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)
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A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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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A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
11
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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.
14
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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)
Excerpt from ESM/2006 Z50 for North America
15
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
3) Circuit Diagram
Excerpt from ESM/2006 Z50 for North America
CHA0376
16
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
Lockup select solenoid valve
Line pressure solenoid valve
Secondary pressure 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)
Excerpt from ESM/2006 Z50 for North America
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.
17
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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.
18
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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.
19
CHA0379
Oil system
Electrical system
TCM
PNP switch
<Main input signal>
Accelerator pedal position
Primary pulley speed
Secondary pulley speed
Second position switch
Manual mode switch
Stepmotor
Line pressure
Shift control valve
Primary pulley
Mechanical system
Excerpt from ESM/2006 Z50 for North America
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
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
20
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
21
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
Accelerator pedal position
Primary pulley speed
Secondary pulley speed
CVT fluid temperature
PNP switchTorque converter lockup ON
Torque converter lockup OFF
Oil systemElectrical system
22
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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.
Excerpt from ESM/2006 Z50 for North America
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.
Excerpt from ESM/2006 Z50 for North America
The EEPROM erasing method is explained in the video program provided here.
Watch a video
23
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
24
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
Lockup select solenoid valve
Torque converterclutch solenoid
valve
Oil pump
Pressureregulator valve
Clutchregulator valve
Torqueconverter
regulator valve
Select switch valve
Select control valve
Excerpt from ESM/2006 Z50 for North America
26
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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
Secondary pressure solenoid valve
Line pressure solenoid valve
Step moto
27
r
Manual valve
Select control valve
Select switch valve & select switch solenoid
Lockup select solenoid valve
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
Excerpt from ESM/2006 Z50 for North America
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
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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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A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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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A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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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A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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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A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
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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A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
33
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.
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
34
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.
A/T DIAGNOSIS STEP 2 CHA ATTN0205AJ
COURSE INSTRUCTOR’S SIGNATURE
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Signature:
Name:
Date: / /
Technician
Name:
Number:
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