Automatic Transaxle System
AUTOMATIC TRANSAXLE SYSTEMDESCRIPTION
The new small sized automatic transaxle (A4CF2) is for gasoline 2.0 engine.
The transaxle (A4CF2) is improved on the durability, fuel consumption and efficiency by the new main features as followed.
The new main features
1. The hydraulic centrifugal oil pressure balance piston.
2. The full line pressure variable control system.
3. The long travel damper clutch.
4. The disc type return spring.
5. The ultra flat torque converter.
FUNCTIONS
TRANSAXLE STRUCTURE
Transaxle Structure:
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.
^ 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 110 to 180 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 loose the weight and selects the parachoid type to improve the processing and the capacity efficiency at the low RPM range.
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 at the 1st speed.
^ 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 overdrive sun gear is held on the transaxle case by the second brake at the 2nd speed.
CLUTCH
The multiple clutches and the one way clutch are used as the transaxle device.
The retainer of each clutch is composed of the precision sheet metal parts to realize the productivity and the light weight.
The hydraulic centrifugal oil pressure balance device places inside the clutch assembly. Generally the oil remained in the piston oil pressure chamber pushes the piston by the centrifugal force. But to prevent the piston from being pushed, the oil filled in between the piston and the return spring retainer occurs the centrifugal force and both of the power is offset so that the piston don't move. In result, it improves the durability and the shift control ability.
1. UNDERDRIVE CLUTCH
The underdrive clutch is engaged at 1st, 2nd and 3rd speed.
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.
2. REVERSE CLUTCH AND OVERDRIVE CLUTCH
The reverse clutch is engaged at the reverse and delivers the driving force of input shaft to the reverse sun gear.
The overdrive clutch is engaged at the 3rd and 4th speed and 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 overdrive clutch retainer and it has the whole overdrive clutch moved to deliver into the hub via retainer.
STRUCTURE OF THE REVERSE AND THE OVERDRIVE CLUTCH
Structure Of The Reverse And The Overdrive Clutch:
PARKING SYSTEM
The parking system for A4CF2 model is the cam type. The roller type installed to the existing new generation AT needs the support to move the roller when operating the parking system and is so complicated. But the cam type for A4CF2 model doesn't need the support and the structure is simply. It only needs the guide to prevent from moving the cam idly.
POWER TRAIN
OPERATION
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 4.5 bar to 10.5 bar according to throttle open angle and shift range to improve the fuel consumption and shift ability.
And the reducing valve which is installed in the valve body makes the solenoid control pressure using the reducing pressure instead of the line pressure like the HIVEC transaxle.
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.
STRUCTURE OF HYDRAULIC CIRCUIT
ELECTRONIC CONTROL SYSTEM
SENSOR AND ACTUATOR FUNCTION
TCM
The TCM which is adapted to the new small sized automatic transaxle (A4CF2) is integrated into the ECM and deliver information via CAN communication.
^ TLE6288 current control chip
The TLE6288 current control chip is installed into the TCM to regulate the solenoid control current and control the oil pressure securely according to the change of the temperature and voltage. In this case, the control signal of solenoid valve is divided into the Peak signal and the Hold signal.
1. Peak: The 12 voltage signal applied to move the solenoid plunger quickly.
2. Hold: The signal applied to keep holding the pulled solenoid valve.
FPC (FLEXIBLE PRINTED CIRCUIT) HARNESS
The FPC (Flexible Printed Circuit) harness is composed of the thin and flat copper in the insulating film like electric wire.
CAN COMMUNICATION
LAYOUT
ECM-TCM CAN COMMUNICATION ERROR MANAGEMENT
