400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 SAE TECHNICAL PAPER SERIES 980819 Honda’s 4 Speed All Clutch To Clutch Automatic Transmission Tatsuyuki Ohashi, Syouji Asatsuke and Hiroshi Moriya Honda R&D Co.,LTD. Thomas R. Noble Honda R&D Americas,Inc. Reprinted From: 1998 Transmission and Driveline Systems Symposium: New Developments and Advanced Concepts in Systems and Components (SP-1324) International Congress and Exposition Detroit, Michigan February 23-26,1998Downloaded from SAE International by University of Liverpool, Sunday, September 09, 2018The appearance of this 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 is given 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 01923 for copying beyond that permitted by Sec-tions 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such ascopying 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. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior wr itten permission of the publisher. ISSN 0148-7191 Copyright 1998 Society of Automotive 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 for the content of the paper. A process is available by which discussions will be printed with the paper if it is p ublished 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 3 00 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE. Printed in USAAll SAE papers, standards, and selected books are abstracted and indexed in the Global Mobility DatabaseDownloaded from SAE International by University of Liverpool, Sunday, September 09, 20181980819 Honda’s 4 Speed All Clutch To Clutch Automatic Transmission Tatsuyuki Ohashi, Syouji Asatsuke and Hiroshi Moriya Honda R&D Co.,LTD. Thomas R. Noble Honda R&D Americas,Inc. Copyright © 1998 Society of Automotive Engineers, Inc. ABSTRACT Honda has developed a new lightweight, compact 4 speed automatic transmission (AT) with electronic controlfor the 1997 Prelude, Acura CL 3.0 and 1998 Accord.The new AT eliminates the 1-2 one-way clutch and 1stgear holding clutch. The two functions of improving shiftquality and fail safe at high speed were formerly depen-dent on conventional one-way clutches. However, newtechnology has been developed which guarantees thesefunctions using three alternate methods (centrifugalhydraulic cancellation mechanism, direct hydraulic con-trol system and new shift logic hydraulic circuit). INTRODUCTION Honda has utilized its original constant mesh type AT withtwo parallel shafts for passenger cars since the develop-ment of its 7 position, 3 speed AT in 1968. A three paral-lel shaft type AT was developed in 1989 with the aim ofshortening the overall AT length. In 1996, further refine-ment lead to the development of a 4 speed all clutch toclutch AT which further shortened the overall AT lengthand reduced the number of parts used. This paper pre-sents the new te