Development of the IM147: An alternative inspection/maintenance mass-emission transient test to address vehicle preconditioning concerns

作     者：Joy, RW Heirigs, PL Torgerson, GD St Denis, M Austin, TC Gordon, J Tefft, B Lindner, J 

作者机构：Sierra Res Inc Sacramento CA USA Gordon Darby Inc Louisville KY USA US EPA Ann Arbor MI USA 

出 版 物：《JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION》 (空气与废物管理协会会志)

年 卷 期：2004年第54卷第3期

页      面：269-285页

核心收录：

学科分类：0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 0706[理学-大气科学] 

主　　题：composite algorithm Vehicle operations CONCERNS second phase Hydrocarbons vehicle Software algorithms Testing Procedures Pretreatment 

摘      要：A series of studies was performed to develop an alternative to the U.S. Environmental Protection Agency s gold standard IM240 mass-based emission test. The new IM147 test was based on the second phase of the IM240 that consists of 147 sec of transient vehicle operation. Paired IM240/IM147 tests were conducted on vehicles ranging from 1981 to 1996 to determine IM147 cutpoints and excess emissions were identified. Additionally, an optimized test procedure was developed that combined possible triplicate IM147s with improved drive trace quality control, fast-pass, and retest methods. The optimized procedure was found to provide improved vehicle preconditioning with a relatively minor decrease in excess emissions identification. Resulting identification rates ranged from 96 to 100% for hydrocarbons (HC), 93-100% for CO, and 93-100% for NO., depending on cutpoint selection, while false failures caused by lack of vehicle preconditioning were reduced to essentially zero. Significant vehicle throughput improvements were achieved through the development of software algorithms involving modal fast-pass and retest procedures. Modal drive trace variation limits also were developed to improve test accuracy. The combination of the algorithms reduced average IM147 test times by nearly 60%.