Candidate: Tiago Simino Macedo
Program: UFSC / POSMEC
Date: November, 2017
Advisor: Victor Juliano De Negri
Abstract: It is well known that the application of automatic transmissions in passenger car have a considerable growing in the world since its beginning in mid’s 1940. In some countries, as United States of America, more than 90% of the vehicles produced are equipped with automatic transmissions. In Brazil, for instance, the number does not reach this level, however the rise of the production numbers are considerably expressive, besides that, there are already many different concepts of automatic transmissions models at the market. The hydraulic circuit on a conventional automatic transmission plays the major role due to its main functions: lubrication and actuation. The actuation function can include the pressure control, the shift timing control, the shift quality and, consequently, the drivability, passenger and drivers comfort, and fuel save. Due to the relevance of the hydraulic circuit in these systems, a significant part of transmission failures is related to a fault on its components. In this work a Matlab/Simulink modelling of the hydraulic circuit of the conventional automatic transmission is introduced. The objective of this study is to reproduce, with the dynamic modelling, the behavior of the hydraulic system and the component movements inside it, to observe the features of the system working in perfect circumstance and compare with the effects of the model with faults inserted. There are considered three groups of faults that can be related to: electric, hydraulic circuit and faults due to the fluid. Is possible to notice effects that are different from the standard behavior of the transmission changing parameters as viscosity and blocking the spool shifting valves, for instance. Differently from other studies, which objective of modelling the transmission is to improve its control system during the shifting process, this present work aims to develop a tool that helps the fault detection, besides the knowledge about the hydraulic system and its behavior.
Key-words: Automatic transmissions. Modelling. Hydraulic circuit. Failures.
Reference: Macedo, T. S. Modelagem e simulação do circuito hidráulico de uma transmissão automática convencional para análise de falhas. 2017. 189 p. Dissertação (Mestrado em Engenharia Mecânica). Universidade Federal de Santa Catarina, Florianópolis.
