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 2007-01-4122 Hybrid Transmission Development for AWD Luxury Cars Masatoshi Ito, Masatoshi Adachi and Hiroatsu Endo Toyota Motor Corp. Akira Isogai, Kenji Omote and Tatsuki Uchida AISIN AW CO., LTD. Powertrain & Fluid Systems Conference & Exhibition Rosemont, Illinois October 29-November 1, 2007The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE's peer review process under th e supervision of the session organi zer. 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 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]: 724-772-4028 Fax: 724-776-3036 For multiple print copies contact: SAE Customer Service Tel: 877-606-7323 (inside USA and Canada)Tel: 724-776-4970 (outside USA)Fax: 724-776-0790Email: [email protected] ISSN 0148-7191 Copyright © 2007 SAE International 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 th e 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 publicat ion by SAE should send the manuscript or a 300 word abstract to Secretary, Engineering Meetings Board, SAE. Printed in USA2007-01-4122 Hybrid Transmission Development for AWD Luxury Cars Toyota Motor Corp. AISIN AW CO., LTD. Copyright © 2007 SAE International ABSTRACT A new hybrid transmission has been developed for all- wheel-drive (AWD) cars, and is used in the new Lexus LS600h and LS600hL for its first application. It has a compact layout consisting of a power-split device, generator, high-output electric motor, and a two-stage speed reduction device. Combined with a 5-liter V-8 engine, it achieves power performance rivaling 6-liter engine vehicles, the fuel efficiency of a medium-class vehicle, and outstanding quietness. This paper describes the structure, performance, and shift control technology of this hybrid transmission. INTRODUCTION Global warming caused by atmospheric greenhouse gases such as CO2 and the worsening of urban air quality have created a demand for more improvements and innovations in technology to reduce vehicle emissions and improve fuel efficiency. Hybrid powertrain systems that combine an internal combustion engine with an electric motor have proven to be effective in minimizing environmental impact, and increasing oil prices continue to stimulate interest in hybrid vehicles. The Toyota Hybrid System (THS) made its debut in the first-generation Toyota Prius. Released in 1997 as the world’s first mass-produced hybrid vehicle, the Prius achieved much higher fuel efficiency than conventional gasoline-engine vehicles. Since then, application of the technology has spread to heavy SUVs and large-engine luxury vehicles, with continual improvements in power, quietness, and fuel efficiency. Figure 1 shows how the sales of Toyota hybrid vehicles have been expanding year by year. In 2007, the L110F hybrid transmission was introduced in the AWD Lexus LS600h and LS600hL. The L110F is based on the L110 transmission for rear-wheel drive vehicles used in the Lexus GS450h. It has been adapted for use with AWD systems and higher engine and motor outputs, and offers a level of refinement and quietness worthy of Lexus’ flagship models.’98/1 ’00/1 ’02/1 ’04/1 ’06/1 ’08/10200,000400,000600,000800,0001,000,0001,200,000 Calen