Automatic Transmission/Transaxle: Description and Operation

Description





Functions






Mechanical system

Function

Torque Converter










Oil Pump










Brakes














Clutch









1. Underdrive Clutch









2. Reverse clutch and overdrive clutch






Structure Of The Reverse And The Overdrive Clutch










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.






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 4.5bar 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.





Electronic Control System




Sensor And Actuator Function






CAN Communication

Layout




ECM- TCM CAN Communication error management