Mechanical System
Function
Torque Converter
The torque converter, as the power plant which delivers the power of engine to the automatic transaxle, consists of 3 elements, 2 phases and 1 stage type.
Scheme 55
- The flowing section form of the torque converter changes the round type to the flat type to reduce the length of the torque converter.
- The maximum operating degree of the damper clutch installed inside the transaxle increases from 11° to 18° to improve the engine revolution change reduction capability and the fuel consumption.
Oil Pump
The oil pump is made of the aluminum (the reaction shaft support) to lose the weight and selects the parachoid type to improve the processing and the capacity efficiency at the low RPM range.
Scheme 56
Brakes
The automatic transaxle (A4CF2) uses the low and reverse brake and the second brake. The low and reverse brake is fixed by the low and reverse annulus gear and overdrive planetary carrier.
- The disc type return spring is applied to the low and reverse brake and it minimizes the slip of the friction material from the uniform spring operation power to improve the durability and reduce the length.
The reverse sun gear is held on the transaxle case by the second brake.
Scheme 57
Scheme 58
Clutch
The multiple clutches and the one way clutch are used as the transaxle device.
The retainer of each clutch is composed of precision sheet metal parts to help in production and light weight.
The hydraulic centrifugal oil pressure balance device is placed inside the clutch assembly.
Generally, the oil remains in the piston oil pressure chamber unless the piston is pushed by centrifugal force. Sometimes the oil is filled in between the piston and the return spring retainer which causes the centrifugal force and return spring retainer to offset power so that the piston won't move. As a result, it improves the durability and the shift control ability.
Scheme 59
Scheme 60
- Underdrive Clutch The driving force of input shaft is delivered to the underdrive sun gear. The operating oil pressure in the underdrive clutch components operates between the piston and the retainer and pushes the piston to the clutch discs to deliver the driving force from the retainer to the hub.
- Reverse Clutch And Overdrive Clutch The reverse clutch delivers the driving force of input shaft to the reverse sun gear. The overdrive clutch delivers the driving force of input shaft to the overdrive planetary carrier and the low and reverse annulus gear. The operating oil pressure of the reverse clutch operates between the reverse clutch retainer and reverse clutch piston and it has the whole overdrive clutch moved to deliver through the hub splines.
Structure Of The Reverse And The Overdrive Clutch
Scheme 61
Parking System
The parking system for A4CF2 model is the cam type.
The original roller type parking system installed in the existing generation AT needs support to move the roller when operating.
This new cam type A4CF2 model doesn't need the support and is simple in structure. It only needs the guide to prevent the cam from moving idly.
Scheme 62
Hydraulic Control System
Main Features
The VFS (Variable Force Solenoid) installed in the valve body is applied to transaxle (A4CF2). VFS varies the line pressure from 4.5bar to 10.5bar according to throttle open angle and shift range to improve the fuel consumption and shift ability.
The reducing valve installed in the valve body makes the solenoid control pressure using the reduced pressure instead of the line pressure.
The material of spool valve in the valve body is changed from the steel to aluminum to reduce the oil leakage by the thermal expansion between the valve body and spool valve at the high temperature.
The switch valve, the solenoid valve and the fail safe valve are operated to drive the vehicle at the 3rd speed and reverse even thought the malfunction of the electronic control parts occur.
Scheme 63
Scheme 64
Sensor And Actuator Function
| Item | Function |
|---|---|
| Input speed sensor | Detect the input shaft RPM (TURBINE RPM) at the OD/RVS retainer |
| Output speed sensor | Detect the output shaft RPM (T/F DRIVEN GEAR RPM) at the T/F driven gear |
| Engine RPM signal | Receive the engine RPM via CAN communication with ECM |
| Fluid temperature sensor | Detect the temperature of ATF through the thermistor |
| Brake switch | Detect the brake operation at the contact switch of the brake pedal |
| ON/OFF solenoid valve (SCSV-A) | Control the hydraulic passage for the shift control |
| VFS solenoid valve | Change the line pressure from 4.5 bar to 10.5 bar according to throttle open angle and shift ranges |
| PCSV-A (SCSV-B) | Control the OD or L/R hydraulic pressure to the pressure control valve for shift control |
| PCSV-B (SCSV-C) | Control the 2/4 or REV hydraulic pressure to the pressure control valve for shift control |
| PCSV-C (SCSV-D) | Control the UD hydraulic pressure to the pressure control valve for shift control |
| PCSV-D (DCCV) | Control the hydraulic pressure for the damper clutch control |
| Cluster | Send the signal of the current position of shift lever and vehicle speed |
SENSOR AND ACTUATOR FUNCTION CHART
CAN Communication
Layout
Scheme 65
ECM-TCM CAN Communication Error Management
| No. | Item | Error management |
|---|---|---|
| 1 | Engine RPM | 3,000 RPM |
| 2 | Engine torque | 80% |
| 3 | Vehicle speed | 0 km/h |
| 4 | A/C Switch | OFF |
| 5 | Engine coolant temperature | 70°C |
| 6 | TPS | 50% |
| 7 | Shift range hold signal | OFF |
ECM-TCM CAN COMMUNICATION ERROR MANAGEMENT CHART