SA E TECHNICAL PAPER SERIES Development of Automatic Transmission Fluid for Slip-Controlled Lock-Up Clutch Systems Takanori Kugimiya, Jun'ichi Mitsui, Narihiko Yoshimura, and Hiroyuki Kaneko Tonen Corp. Hideaki Akamatsu, Fumio Ueda, and Takanori Nakada Toyota Motor Corp. Shoji Akiyama Esso Sekiyu K.K. Reprinted from: Engine Lubricants (SP-1121) The Engineering Society Fuels & Lubricants mA=For Advancing Mobility Meeting & Exposition and Sea Air and Space, Toronto, Ontario INTERNATIONAL October 16-1 9,1995 400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (41 2)776-4841 Fax:(412)776-5760 Downloaded from SAE International by University of Michigan, Saturday, August 11, 2018The appearance of the ISSN code at the bottom of this page indicates SAE's consent that copies of the paper may be made for personal or internal use of specific clients. This consent isgiven on the condition, however, that the copier pay a $7.00 per article copy fee through the Copyright Clearance Center, Inc. Operations Center, 222 Rosewood Drive, Danvers, MA 01 923 for copying beyond that permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale. SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Customer Sales and Satisfaction Department. Quantity reprint rates can be obtained from the Customer Sales and Satisfaction Department. To request permission to reprint a technical paper or permission to use copyrighted SAE publications in other works, contact the SAE Publications Group. All SAE papers, standads, and selected books rare abstracted and indexed in the Globel IMbilily Database. No part of this publication may by reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. ISSN 0148-7191 Copyrlght 1995 Society of A~utomotive Engineers, Inc. Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible lor the content of the paper. A process is available by which discussions will be printed with the paper if it is published in SAE transactions. For permission to publish this paper in full or in part, contact the SAE Publications Group. Persons wishing to submit papers to be considered for presentation or publication through SAE should send the manuscript or a 300 word abstract of a proposed manuscript to: Secretary, Engineering Activity Board, SAE. Printed In USA ~O-IX)~D/PG Downloaded from SAE International by University of Michigan, Saturday, August 11, 2018Development of Automatic Transmission Fluid for Slip-Controlled Lock-Up Clutch Systems Takanori Kugimiya, Jun'ichi Mitsui, Narihiko Yoshimura, and Hiroyuki Kaneko Tonen Corp. Hideaki Akamatsu, Fumio Ueda, and Takanori Nakada Toyota Motor Corp. Shoji Akiyama Esso Sekiyu K.K. Copyright 1995 Society of Automotive Engineers, Inc. ABSTRACT Slip-controlled lock-up clutch systems are very efficient and greatly improve fuel economy. On the other hand, these systems can cause unstable vibrations including those known as "shudder vibrations" . In this study, the authors made a theoretical analysis of these unstable vibrations to clarify the fundamental frictional properties of automatic transmission fluids (ATFs) required for slip-controlled lock-up clutch systems. Based on this analysis, we established lubricant technology having a sufficient anti-shudder property and high torque capacity. Further, we developed a new test apparatus to evaluate the anti-shudder durability for lubricant development. INTRODUCTION Slip-controlled lock-up clutch systems were devised to improve fuel economy[l], [2]. In the case of normal lock-up clutch