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 2006-01-1358 Investigation of the Effects of Wheel Slip on Vehicle Emissions and Fuel Economy Noelle D. Baker and Kate Presnell Ford Motor Company 2006 World Congress Detroit, Michigan April 3-6, 2006 Downloaded from SAE International by University of New South Wales, Sunday, August 26, 2018The 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 © 2006 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 USADownloaded from SAE International by University of New South Wales, Sunday, August 26, 2018ABSTRACT BACKGROUND Powertrain developers have suggested that slip at the vehicle tire and chassis dynamometer contact point for US06 emissions testing causes unmanageable variability. In order to counteract slip, some developers have been requesting their vehicles be strapped down tighter. Strapping a vehicle down tighter may lead to unrepresentatively low fuel economy and high emissions (many tests are run FTP/Hwy/US06 consecutively). EXPERIMENT A study was developed to investigate the effects of dynamometer roll surface roughness and vehicle restraint strap tension on fuel economy, emissions, and the amount of wheel slip. In addition, a correlation may be established between wheel slip and fuel economy and emissions. A three factor, two-level, full factorial design with three replicates was planned. The factors were dynamometer surface roughness, vehicle, and strap tension. DATA The data collected included dynamometer speed, vehicle speed, fuel economy, and emissions (HC, CO, NO x, CO 2) for FTP, Hwy, and US06 test cycles. The dynamometer roll surface roughness was measured for the two test cells used, and the strap tension was set at either a tight setting or 0 tension for each test (where tight represents the most a driver could reasonably tighten the straps by hand and 0 tension means no strap was used to secure the vehicle). The slip criterion was defined as the amount of time when the vehicle speed was more than 2mph different than the dynamometer speed. RESULTS Results from this experiment revealed the restraint condition was not well correlated to emissions, fuel economy, or the amount of slip. The dynamometer roll surface roughness had the largest impact on the amount of slip. A follow-up experiment was conducted with two additional vehicles that were known to have slip issues. Restraint was eliminated as a factor in this experiment. Results from this set of tests confirmed results from the first experiment; the dynamometer with the rougher roll surface showed the