8.1.3. Electronic and hydraulic control system of 4-staged AT
Detailed information on the device and the principle of action of automatic transmissions is provided in the Guide to automatic transmissions of the ARUS series No. 179 (ISBN 5-89744-069-7).
The main objective of the transmission line is transfer of the torque developed by the engine to driving wheels of the car. The organization of the correct transfer relations in the AT reduktorny hubs allows to minimize power costs of the power unit of transfer of rotation due to maintenance of optimum turns.
Control of transmission is exercised in the hydraulic way according to the commands of the electronic module of management (TCM) developed on the basis of the analysis of the data arriving from various information sensors. TCM carries out the choice of the required transfer by activation of electromagnetic managing directors of the valves providing supply of hydraulic liquid a contour of the corresponding clutch coupling. Precision control of the operating pressure guarantees absence of stress of switchings and accuracy of definition of the moments of blocking of the hydrotransformer. The function chart of an electronic and hydraulic control system of AT — see an illustration the Function chart of an electronic and hydraulic control system of AT.
The scheme of placement on the car of components of an electric part of a control system of AT — see the illustration Scheme of Placement on the car of components of an electric part of a control system of AT.
The principles of functioning of a hydraulic part of a control system — see illustrations Design features of elements of a hydraulic path of a control system of AT and the Schematic diagram of functioning of a hydraulic contour of management of AT. The key TCM under control parameters are: switching moment; moment of blocking and moment of braking by the engine.
Also as well as the control system of the engine a control system of transmission is included in a chain of onboard system of self-diagnostics of OBD-II and in case of identification of any sort of violations the corresponding diagnostic code is brought in memory of TCM. An order of reading of codes of malfunctions — see Failure diagnostics of AT - the general information. The list of the main codes is provided in Specifications (see. Transmission line).