SAETECHNICALPAPERSERIES 970684 Development ofaNew 4WD System: All-Mode 4WD Toshiharu Takasaki, Kunihiko Suzuki, Shigeo Murata, Tomoyuki Hará, and Kouji Nishio Nissan Motor Co., Ltd. Reprinted from: 1997 Transmission andDriveline Systems Symposium: Transmission Systems, Components, Gears andFriction andFluid Materials (SP-1241) International Congress &ExpositionDetroit, Michigan February 24-27, 1997 400Commonwealth Drive, Warrendale, PA15096-0001 U.S.A. Tel:(412)776-4841 Fax:(412)776-5760 Downloaded from SAE International by Tsinghua University, Saturday, June 27, 2020Theappearance oftheISSN code atthebottom ofthispage indicates SAE's consent that copiesof thepaper maybemade for personalor internaluseofspecificclients.Thisconsent isgiven onthecondition however, thatthecopier paya$7.00 perarticle copyfeethrough theCopyright Clearance Center, Inc.Operations Center, 222Rosewood Drive, Danvers, MA01923for copyingbeyond that permittedby Sections 107or 108oftheU.S.Copyright Law.Thisconsentd snotextendtootherkindsofcopyingsuchascopyingforgeneral distribution, foradvertisingor promotional purposes, forcreating new collectiveworks,or forresale. SAE routinely stocks printed papers foraperiod ofthree years following date ofpublication. Direct yourorders to SAECustomer SalesandSatisfactionDepartment. Quantity reprint rates canbeobtained fromtheCustomer Sales andSatisfaction Depart ment. Torequest permission toreprint atechnical paper orpermission tousecopyrighted SAE publications inother works, contact theSAE Publications Group. Nopartofthispublication maybyreproduced inanyform, inanelectronic; retrieval system orotherwise, without thepriorwritten permission ofthepublisher. ISSN0148-7191 Copyright 1997 Society ofAutomotive Engineers, Inc. Positions andopinions advanced inthispaper arethose oftheauthor(s) andnotnecessarily those ofSAE. Theauthor issolely responsible forthecontent ofthepaper. Aprocess is available bywhich discussions willbeprinted withthepaper ifitispublished inSAE Transactions. Forpermission topublish thispaper infullorinpart, contact theSAE Publications Group. Persons wishing tosubmit papers tobeconsidered forpresentation orpublicationthrough SAEshould send themanuscript ora300word abstract ofaproposed manuscript to: Secretary, Engineering Meetings Board, SAE. Printed inUSA Downloaded from SAE International by Tsinghua University, Saturday, June 27, 2020970684 Development ofaNew 4WD System:All-Mode 4WD Toshiharu Takasaki, Kunihiko Suzuki, Shigeo Murata, Tomoyuki Hará, andKouji Nishio Nissan Motor Co., Ltd. Copyright 1997 Society ofAutomotive Engineers, Inc. ABSTRACT This paper presents anewelectronic torque split four- wheel-drive system called All-Mode 4WD, which hasbeen adopted inthelatest generation ofsport-utility vehicles (SUVs). Asatorque split system designed specifically for SUV use, itprovides stable driving performance matching thedriver's intentions under allsorts ofoperating con- ditions, from acompletely natural on-road driving feelto powerful traction foroff-road travel.INTRODUCTION The All-Mode 4WD isanew 4WD system which consists ofatransfer unitcontaining awetmultiplate clutch andahydraulic control system, andemploys front andrear speed sensors aswell asaacceleration sensor. The system enables SUVs tomeet therequirement forgood driving performance under both on-and off-road conditions. Interms ofon-road utility, rear-wheel-drive provides better performance than 4WD with respect tocornering, braking (ABS) andfueleconomy. Asforoff-road utility, 51 Downloaded from SAE International by Tsinghua University, Saturday, June 27, 2020rigid 4WD delivers better tractive performance. Designed around arear-wheel-drive layout, itauto matically distributes torque tothefront wheels toobtain the optimum torque distribution from rear-wheel-drive torigid 4WD. Thebesttorque split isdetermined according tothe roadconditions andvehicle status toprovide consistently high performance. HISTORICAL TREND IN4WD SYSTEMS FOR SUVS 4WD s