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 2007-01-3747 Vehicle Implementation of a GM RWD Six-Speed Integrated-Friction-Launch Automatic Transmission Farzad Samie, Chunhao Joseph Lee, Kumar Hebbale and Chi-Kuan Kao General Motors 14th Asia Pacific Automotive Engineering Conference Hollywood, California, USA August 5-8, 2007Downloaded from SAE International by Univ of Nottingham - Kings Meadow Campus, Sunday, August 12, 2018By mandate of the Engineering Meetings Board, this paper has been approved for SAE publication upon completion of a peer review process by a minimum of three (3) industry experts under th e supervision of the session organizer. All rights reserved. No part of this publication ma y be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electroni c, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. For permission and licen sing requests contact: SAE Permissions 400 Commonwealth DriveWarrendale, PA 15096-0001-USAEmail: permissions@sae.orgFax: 724-776-3036Tel: 724-772-4028 For multiple print copies contact: SAE Customer ServiceTel: 877-606-7323 (in side USA and Canada) Tel: 724-776-4970 (outside USA)Fax: 724-776-0790Email: CustomerService@sae.org ISSN 0148-7191Copyright © 2007 General Motors Global Technology Operations, Inc. Published by SAE International with permission. Positions and opinions advanced in th is paper are those of the autho r(s) and not necessarily those of SAE. The author is solely respo nsible 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. Persons wishing to submit pape rs to be considered for presentation or publication by SAE should send the manuscript or a 300 word abstract of a proposed ma nuscript to: Secretary, Eng ineering Meetings Board, SAE. Printed in USADownloaded from SAE International by Univ of Nottingham - Kings Meadow Campus, Sunday, August 12, 2018ABSTRACT Friction Launch transmissions use a wet multi-plate clutch to replace the torque converter in an automatic transmission. By using one of the range clutches inside the transmission, the benefits of this integrated friction launch technology (IFL), such as reduction in mass, packaging, and cost, can be enhanced. The availability of new automatic transmissions with higher number of speeds and wider ratio spreads makes IFL technology more viable than ever before. The new GM Rear-Wheel-Drive (RWD) six-speed transmission has paved the way for a full implementation of integrated friction launch technology in a GM full size Sport-Utility Vehicle (SUV). This project focuses on both hardware and control issues with the friction launch clutch. The hardware issues include designing the clutch for launch energy, cooling, and durability. The control issues include developing robust control algorithms for launch and creep, and providing damping to the driveline, when required, and ensuring acceptable vehicle drivability. This paper describes in detail the design of the clutch and the cooling system, and the development of the launch and creep control algorithms. Vehicle test data presented in this report show that High-Energy-Capacity Clutch (HECC) design as a friction-launch device can handle a wide-open throttle launch for a full-size truck application. The control strategy developed in this project significantly reduces the gap between the drivability of a starting clutch vehicle and a torque converter equipped vehicle. Also, vehicle fuel economy tests revealed promising fuel economy improvements over production intent 6-speed RWD transmission. INTRODUCTION A torque converter is a hydro-mechanical device that couples the engine with the transmission in an automatic transmission. The function of the torque converter is to launch the vehicle in