400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 Web: www.sae.org SAE TECHNICAL PAPER SERIES 2003-01-0056 NVH Optimization of the New 2.5L HSDI Diesel Engine with Common Rail Taeik Kim, Insoo Jung, Douck-Han Bae and Seung-Dong Yeo Hyundai Motor Company 2003 SAE World Congress Detroit, Michigan March 3-6, 2003Downloaded from SAE International by University of Auckland, Sunday, August 05, 2018All 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]: 724-772-4891Tel: 724-772-4028 For multiple print copies contact: SAE Customer ServiceTel: 877-606-7323 (inside USA and Canada)Tel: 724-776-4970 (outside USA)Fax: 724-776-1615Email: [email protected] ISSN 0148-7191Copyright © 2003 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 discussionswill be printed with the paper if it is published in SAE Transactions. Persons wishing to submit papers to be considered fo r presentation or publication by SAE should send the manuscript or a 300 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE.Printed in USADownloaded from SAE International by University of Auckland, Sunday, August 05, 2018 Taeik Kim, Insoo Jung, Douck-Han Bae and Seung-Dong Yeo Hyundai Motor Company Copyright © 2003 SAE International ABSTRACT This paper presents NVH optimization procedure for the 2.5L I4 common rail diesel engine. Distinctive design feature is the low noise timing chain system which realized by chain case modification and meshing noise improvement. The former was effective for reduction of sound level and the later was for sound quality. Combustion excitation force, vibration transmission in engine structure were also improved and countermeasured to achieve powerful and comfortable Sports Utility Vehicle. INTRODUCTION As adoption of diesel engines are expanding from RV to passenger cars, diesel engine noise has been an matter of concern for automobile manufactures. This paper presents NVH optimization procedure of a 2.5L, 33Kg-m max torque, BOSCH common rail system equipped direct injection diesel engine which was installed into the SUV “SORENTO” and VAN “STAREX” from 2002. NVH optimization was performed on 1) Timing chain 2) combustion excitation and 3) Excitation transfer path. With the sprocket meshing and chain guide contact, timing chain noise is inferior to timing belt noise. For the high speed diesel engines, fuel injection is the key components which control combustion noise, emission and engine torque. So best injection variable should be determined. Best injection variables were choosen from injection swing test in acoustic test benches and checked in vehicle drive test. Engine cylinder head was improved to decrease transfer of combustion excitation force to noise radiation. Fig.1 2.5L I4 common rail diesel engine. TIMING CHAIN NOISE IMPROVEMENT The engine was equipped with timing belt system at the initial stage of development but replaced by chain system for durability and reduction of engine size. As a result, engine front noise became worse by 3~5.0dBA. Fig.2 Front 1m noise at initial stage 1000 1500 2000 2500 3000 3500 4000 ENG RPM Belt Chain 4 dBA SPL(dBA) Diesel Engine with Common Rail NVH Optimization of the New 2.5L HSDI 2003-01-0056 Downloaded from SAE International by University of Auckland, Sunday, August 05, 2018 To improve chain noise, two kinds of noise s