The Engineering Meetings Board has approved this paper for publicat ion. It has successfully completed SAE’s peer review process under the supervision of the session organizer. This process requires a minimum of three (3 ) reviews by industry experts. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form o r by any means, electronic, mechanical, photocopying, recording, or otherwi se, without the prior written permission of SAE. ISSN 0148-7191 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. SAE Customer Service: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: [email protected] SAE Web Address: http://www.sae.org Printed in USA ABSTRACT JATCO developed an all new 7-speed automatic transmission (AT) for front engine rear wheel drive medium and large vehicles. This transmission features high torque capacity, downsizing, and innovative technology to realize fuel economy improvement. In addition, it offers excellent driveability and shift responsiveness for maximum driver satisfaction and pleasibility. Specifically , the new lock-up system and adaptive shift controls add value in terms of “Joy of Driving” while providing a 7% improvement in fuel economy over the 5 speed AT it replaces. 1. INTRODUCTION With today’s increasing concern for the prevention of global warming, it is import ant we make adjustments to our daily lifestyle. A key com parison factor for “value” of a vehicle is determined by how much CO2 emissions are reduced. On the other hand, for customers buying / driving FR vehicles, driveability, performance, and handling are key factors that determine the value of a vehicle. To answer such various demands in a higher dimension, the new 7-speed AT for FR (RWD) was developed. This report provides an outline of the development from concept up to the final production product. 2. DEVELOPMENT OBJECTIVES When this new transmission was developed, the following three objectives were targeted: 1. Consideration of Global Environment (Technology to support fuel economy improvement) 2. Offering Products to Various Customers (An optimal balance between a wide range of applicable torque, performance, and cost) 3. Offering Customer-oriented Impressive Features (Technology supporting driving pleasure) 2.1. CONSIDERATION OF GLOBAL ENVIRONMENT - A target was set to improve fuel economy without sacrificing drivability and or performance. (Fig.1) Fig.1 Consideration of Global Environment 2.2. OFFERING PRODUCTS TO VARIOUS CUSTOMERS - Cost reduction was a major objective; to make the vehicle available to a larger population. (Fig.2) *9-2009-01-0512* 2009-01-0512 Development of All New 7-speed Autom atic Transmission for RWD Vehicles Kazuhiro Takatori , Shinichi Tazunegi and Naoki Takahashi JATCO Ltd. Copyright © 2009 SAE InternationalDownloaded from SAE International by American Univ of Beirut, Sunday, July 29, 2018 Fig.2 Offering Products to Various Customer 2.3. OFFERING CUSTOMER-ORIENTED IMPRESSIVE FEATURES - The key terms, "Sharpness" and "Richness" were introduced to the development process. These words were more customer friendly, and made it easier to express what driving pleasure was. Fig.3 shows the meaning of "Sharpness" and "Comfort". It aimed at the balance in a higher dimension though these two performance characteristics are completely opposite. (Fig.4) Fig.3 Key words “Sharpness” and “Richness” Fig.4 Offering Customer-oriented Impressive Features A development plan was set up to first meet the objective of "Offering cu stomer-oriented Impressive features.” Vehicle performance requir