-A The Engineering Society For Advancing Mobility Jr(lt and Sea Air and Space, INTERNATIONAL^" 400 COMMONWEALTH DRIVE, WARRENDALE, PA 15096-0001 USA. Transmission Modulating Valve Simulation and Simulation Verification Hugh C. Morris Caterpillar Inc. MAY 3 1990 Sku LIBRARY 41st Annual Earthmoving Industry Conference Peoria, Illinois April 3-5, 1990 Downloaded from SAE International by University of Wisconsin - Madison , Sunday, September 09, 2018The appearance of the ISSN code at the bottom of this page indicates SAE's consent that copies of the paper may be made for personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay a $5.00 per article copy fee through the Copyright Clearance Center, Inc., Operations Center, 27 Congress St., Salem, MA 01 970 for copying beyond that permitted by Sections 107or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale. SAE routinely stocks printed papers for a period of three years following date of publication. Direct your orders to SAE Customer Service Department. To obtain quantity reprint rates, permission to reprint a technical paper or permission to use copyrighted SAE publications in other works, contact the SAE Publications Group. - -- - - -- - - --=-=- 7 - -- - - - -- A - - -. -- - -- - - --_ -- - --. - -- - .= All SAE papers are -- - - - . - - - - - -- abstract& and &ex& In - - - - - --- - - -- - - - .- tim SAEGW M&CtyOat.base. -- - --- - -- -- --- . .-- -- . ------. - -- -- - ----- ----- -- - -- - . - - - - . - - - - - - . . - - - - - - SAE QLO(UL MOBILITV DATABASE No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior writ- ten permission of the publisher. ISSN 0148-7191 Copyright 1990 Society of Automotive Engineers, Inc. Positions and opinions advanced in this paper are those of the Persons wishing to submit papers to be considered for presen- author(s)and not necessarily thoseof SAE. Theauthor issolely tation or publication through SAE should send the manuscript responsible for the content of the paper. A process is available or a300 word abstract of a proposed manuscript to: Secretary, by which discussions will be printed with the paper if it is Engineering Activity Board, SAE. published in SAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Division. Printed In USA Downloaded from SAE International by University of Wisconsin - Madison , Sunday, September 09, 2018Transmission Modulating Valve Simulation and Simulation Verification Hugh C. Morris Caterpillar Inc. ABSTRACT This paper presents a response to the question: Simulation - mathematical manipulation or useful design tool? A mathematical model of a modulating valve in a transmission control system was developed to predict clutch pressure modulation characteristics. The transmission control system was previously reported in SAE Paper 850783 - "Electronic/Hydraulic Transmission Control System for Off-Highway Vehi- cles". The comparison of simulation predictions with test data illustrates the effectiveness of simulation as a design tool. THE EVOLUTION OF COMPUTER hardware and simulation software has resulted in increased interest and usage of simulation for dynamic analysis of hydraulic systems. Most commercially available soft- ware is relatively easy to learn to use. The application of such software and the modeling techniques involved require a longer learning curve. Learning these tech- niques and becoming effective in simulation application is significantly enhanced by correlation of simulation results with actual system test results. SIMULATION ANALYSIS The simulation process