400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-0790 Web: www.sae.org SAE TECHNICAL PAPER SERIES 2008-01-0538 Adaptive nth Order Lookup Table used in Transmission Double Swap Shift Control Hussein Dourra and Ali Mourtada Chrysler LLC 2008 World Congress Detroit, Michigan April 14-17, 2008Downloaded from SAE International by American Univ of Beirut, Tuesday, July 31, 2018By mandate of the Engin eering Meetings Board, th is paper has been approved for SAE publication upon completion of a peer review process by a minimum of three (3) industry experts under the supervision of the session organizer. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise,without the prior written permission of SAE. For permission and licensing requests contact: SAE Permissions 400 Commonwealth DriveWarrendale, PA 15096-0001-USAEmail: [email protected]: 724-772-4028Fax: 724-776-3036 For multiple print copies contact: SAE Customer ServiceTel: 877-606-7323 (inside USA and Canada)Tel: 724-776-4970 (outside USA)Fax: 724-776-0790Email: Customer [email protected] ISSN 0148-7191Copyright © 2008 SAE InternationalPositions 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 pap er if it is publishe d in SAE Transactions. Persons wishing to submit papers to be considered for presentation or publication by SAE should send themanuscript or a 300 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE. Printed in USADownloaded from SAE International by American Univ of Beirut, Tuesday, July 31, 20181 The new Chrysler six-speed transaxle makes use of an underdrive assembly to extend a four-speed automatic transmission to six-speed. It is achieved by introducing double-swap shifts. During double-swap shift, learning the initial clutch torque capacity of the underdrive assembly’s subsystem has a direct impact on the shift quality. A new method is proposed to compute and learn the initial clutch torque capacity of the releasing element. In this paper, we will outline a new mathematical method to compute and learn the accurate starting point of the clutch torque capacity for double swap shift control. The performance of the shift is demonstrated and the importance of the adaptation to shift quality is highlighted. An nth order lookup table is presented; this table contains n rows and m columns. Every row defines a relationship between the dependent variable such as actuator duty cycle and one independent variable such as transmission oil temperature, input torque or battery voltage. For given values of the independent variables, one dependent variable is computed as a function of weighted linear combination of n different interpolations. An example is given to calculate the initial duty cycle based on two independent variables (transmission oil temperature and the input torque). Based on shift results, this method is demonstrated to be effective, and accurate. Introduction Electronic clutch-to-clutch control in automatic transmissions was introduced by Chrysler Corporation in 1988, and is widely used by the industry now. The challenge in this control is the transfer of clutch torque from the releasing to the applying clutch without producing undesired output torque transients. The releasing and applying clutches are called shift elements. Precise shift control requires precise timing of the releasing and applying shift elements, and therefore, shift adaptation is of great importance to produce excellent and consistent shift quality. The new six-speed transmission design at Chrysler LLC consists of a main-box asse