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 2008-01-2578 A New Method of Inertia Simulation in Brake Dynamometer Testing JiLin University 26th Annual Brake Colloquium & Exhibition San Antonio, Texas October 12-15, 2008Jijie Ma, Boda Wu, Xiaoyu Liu and Jingyang Sun Downloaded from SAE International by University of Auckland, Saturday, August 04, 2018The Engineering Meetings Board has approved this pap er for publication. It has successfully completed SAE's peer review process under th e 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 or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior writ ten permission of SAE. For permission and licen sing 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 • 2008 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 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 to Secr etary, Engineering Meetings Board, SAE.Downloaded from SAE International by University of Auckland, Saturday, August 04, 2018ABSTRACT A new method of inertia simulation (named the energy compensation method) using work of electromotor for energy compensation during brake application is presented in this paper, where advantages and disadvantages of three common inertia simulating methods are compared at first. Mathematical model is described. Consequent orthogonal experiment unfolds the rule of some key factors of energy compensation including working period of electromotor, start point and ending condition of compensation. Limitations as well as corresponding solutions are discussed in the end. Energy compensation method is shown to be an effective way of simulating target inertia in brake dynamometer testing. INTRODUCTION The inertia dynamometer is an authoritative tool in evaluating friction behavior of ve hicle brake. A typical format of this machine usually contains an inertia section for simulating vehicle inertia, a test section for mounting the brake assembly, and a central control section. This paper will present a new method of inertia simulation in brake dynamometer testing. Three common inertia simulating methods will be compared at first. A direct means of inertia simulation named mechanical inertia is to mount disks on a shaft driven by a motor. The inertia disks are often arranged in geometric progression or arithmetic progression. Once disk arrangement is determined, inertia adjustment is riveted to be in discrete steps. Since each vehicle size requires different amount of inertia, the number of disks must be large enou gh to meet the inertia setting precision requirement however length of the shaft limits thenumber of inertia disks. Another serious defect of mechanical inertia lies in the deficiency of self-adjusting capability of the inertia. It has no way to correct in ertia error confirmed by central controller . The alternative approach is electric inertia using the motor inserting or absorbing power during brake application. Electric inertia is usually im plemented through controlling torque or speed of elec