400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 SAE TECHNICAL PAPER SERIES 2002-01-1252 Development of a New Clutch-to-Clutch Shift Control Technology Shushan Bai, Robert L. Moses, Todd Schanz and Michael J. Gorman GM Powertrain, General Motors Corp. R eprinted From: Transmission and Driveline Systems Symposium 2002 (SP–1655) SAE 2002 World Congress Detroit, Michigan March 4-7, 2002Downloaded from SAE International by Swinburne Univ Of Technology, Thursday, August 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 per article copy fee through the Copyright Clearance Center, Inc. OperationsCenter, 222 Rosewood Drive, Danvers, MA 01923 for copying beyond that permitted by Sections 107 or108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such as copying forgeneral distribution, for advertising or promotional purposes, for creating new collective works, or forresale. 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 © 2002 Society of Automotive Engineers, Inc. Positions and opinions advanced in this paper are those of the aut hor(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 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 consi dered for presentation or publication through SAE should send the manuscript or a 3 00 word abstract of a proposed manuscript to: Se cretary, Engineering M eetings Board, SAE. Printed in USAAll SAE papers, standards, and selected books are abstracted and indexed in the Global Mobility DatabaseDownloaded from SAE International by Swinburne Univ Of Technology, Thursday, August 09, 20182002-01-1252 Development of a New Clutch-to-Clutch Shift Control Technology Shushan Bai, Robert L. Moses, Todd Schanz and Michael J. Gorman GM Powertrain, General Motors Corp. Copyright © 2002 Society of Automotive Engineers, Inc. ABSTRACT The non-freewheeler shift control technology (clutch-to-clutch shift) is the key enabler for a compact, low mass and low cost automatic transmission design,especially when the transmission has an extendednumber of speeds. For the past two decades, a varietyof non-freewheeler shift control technologies have beendeveloped. The Allison Transmission LCT, the SaturnMP7 and the Chrysler 42LE can be considered asrepresentatives of those technologies. All of thosetechnologies (traditional) use two independent pressurecontrol valves to control the oncoming and the off-goingclutches. The synchronization of these two clutches isaccomplished by means of electronic controls. Due tothe variation of the system parameters and the difficultyof detecting the oncoming clutch fill, the consistencyand robustness have always been the issues, even afteryears of development. To improve the consistency androbustness of the control systems, the authors havedeveloped a new non-freewheeler shift controltechnology. This new technology uses a hydraulicwashout technique to control the synchronization of theoncoming and the off-going clutches. The test resultsshow that this new technology greatly improves the shiftquality, consistency and system robustness, andreduces the calibration work over the traditional clutch-to-clu