SAE TECHNICAL PAPER SERIES Fundamental Studies on ATF Friction I. C. D. Tipton and E. A. Schiferl Lubrizol Corp. Reprinted from: Automotive Lubricants and Lubrication (SP-1273) MAY 0 8 1997 LIBRARY The Engineering Society Advancing Mobmy mo and Sea Air and Space, INTERNATIONAL International Spring Fuels & Lubricants Meeting Dearborn, Michigan Mav 5-8.1997 400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (412)776-4841 Fax:(412)776-5760 Downloaded from SAE International by University of New South Wales, Wednesday, September 19, 2018isgivenonthemndilion however, thatthecopierpay a$7.00perarticlewpyfeethrough meCo~MlohtCleamnceCenter. Inc. OwrationsCenter. 222 Rceewood Drive. Danveffi. .. - . Law. ~hismnsentdoesnote~endtootherkiridsofco~yin~suchasm~yin~for&n& distribution,foradvertisingorpromotio~lpurposes,forcre~ngnewcollectiveworks,or forresale. SAE routinely stocks printed papers for a period of three years following date of publication. DirectyourorderstoSAECustorner SalesandSaMaction Department. Cluantilvreorint ratescan beobtainedfromlheCustomer Sales and Satisfaction Deoart To requestpermissiontoreprintatechnicalpaperorpenissiontousempyrightedSAE publicationsin otherworks,contacttheSAEPublicationsGmup. All SAEpapers, standards, and selected booksareahstradsdandindexedmtkSAE Glabalhfck@yDa&base. Nopartofthb:publcationmaybyreproducedinanyfo~,inandedronic~trievalsystem orothemrise, withoutthe priorwritten perrnissionoflhepublkher. Pcsibomandopinionsadvancedin~spaperare~of~e~or(s)andndnecess~ly thoseof SAE. Theauthorissdelvreswnsibleforthecontentoftheoaoer. A~rccessis available by which discussions kill de pnnted with the paper if it is iublishedin SAE Transactions. Forperrn r in full or in part, contact the SAE PuMicationsGroup. ' 1 Personswishingtosubmitpaperstobe~ideredforprese~onorpl~1cati~1through SAE shouldsendthemanuscript ora300wordabstractof a proposed manuscript to: Printed in USA Downloaded from SAE International by University of New South Wales, Wednesday, September 19, 2018Fundamental Studies on ATF Friction I. C. D. Tipton and E. A. Schiferl Lubrizol Corp. Copyright 1997 Society of Automotive Engineers. Inc. ABSTRACT Automatic transmission clutches are complex tribo- logical systems. Frictional performance is controlled by the interaction of base fluids, additive components, com- position clutches, and steel reaction plates with varying energy inputs and thermal stresses in an oxidizing envi- ronment. This paper, rather than addressing fully formu- lated fluid performance in such a system, takes a more fundamental approach where the number of system vari- ables is reduced and the relative effects of formulation variables on system performance can be better examined. Relationships among observed friction performance, sys- tem oxidation, friction member condition, and representa- tive performance additives are explored using a synthetic base fluid and a conventionally refined mineral base fluid. 1. INTRODUCTION Designers of automatic transmissions and other types of power transmission systems containing wet clutches are concerned with the performance and durability of these devices. Power transmission systems are often designed to work with an existing fluid that is in use in similar equip- ment made by that manufacturer. Design variables such as friction material, clutch surface areas, operating tem- peratures, apply pressures, etc. are chosen to give the required durability and performance. However, the chem- istry of the original equipment fluid may be quite different from some approved service fluids for that equipment. Moreover, a change in the fluid used at a factory can lead to unexpected performance changes. Similarly, designers of clutch materials are often asked to develop materials for a given application that have im- proved durability, lower or higher static friction, higher energy capacity, and higher engagement tor