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原文传递 Very Low PM Mass Measurements Phase 2: Evaluation of Partial Flow Dilution, Executive Summary

题名：	Very Low PM Mass Measurements Phase 2: Evaluation of Partial Flow Dilution, Executive Summary
作者：	Johnson, K.; Kittelson, D.
关键词：	Light duty vehicles (LDV)##Emissions##Particulate matter (PM)##Partial flow dilution (PFD)##Low-emission vehicle (LEV)##Filter face velocity (FFV)##Decreasing dilution factor (DF)##Constant volume sampling (CVS)##Exhaust flow##
摘要：	Present motor vehicle particulate matter (PM) emissions measurement regulations (Code of Federal Regulations [CFR] 40, Parts 1065 and 1066) require gravimetric determination of PM collected onto filter media. There have been discussions about whether current sampling and measurement practices are sufficiently accurate in quantifying PM at the upcoming 3 mg/mi standards, and even more so at the 1 mg/mi PM emissions standards for low-emission vehicle (LEV) III light-duty vehicles. Although PM mass measurement methodologies were improved considerably with the application of 40 CFR Part 1065 to the 2007 PM standards for heavy-duty engines, there is a need to improve the understanding of and the confidence in mass measurements for light-duty vehicles given the potential for significant impact on the automotive industry. CRC’s E-99 Phase 1 project was launched to investigate long-standing questions about the measurement of particulate matter (PM2.5) emissions from motor vehicle exhaust at very low levels. E-99 phase 1 evaluated the impacts of increasing filter face velocity (FFV), decreasing dilution factor (DF), and collecting cumulative filters on PM filter measurements. Two of these, increased FFV and single filter, have been included in EPA Part 1066 regulations. The resulting increase in signal to noise of filter weighing eases concerns about measurement variability at 3 mg/mi; however, these concerns remain at 1 mg/mi. The purpose of E-99 Phase 2 (E-99-2) is to evaluate commercially available partial flow dilution (PFD) devices, particularly in regard to their equivalency with the standard CVS tunnel method and ability to provide reproducible measurements at low PM emission levels. This project is designed to address a number of open questions about the application of PFDs for light duty vehicles (LDV) exhaust emissions testing, including: (1) whether partial flow units show equivalency to full flow constant volume sampling (CVS), (2) what the noise sources for PFD versus CVS sampling are, (3) what is needed to “condition” or “manage contamination” for PFD and CVS sampling systems, (4) how sensitive PFD performance is to exhaust flow measurement, and (5) what improvements can provide more efficient and accurate partial flow system performance in light-duty chassis dynamometer testing at Tier 3 PM standard levels. To answer these questions, a series of tests were conducted with different PFDs and exhaust flow meters (EFMs), with and without vehicle exhaust. Initial tests were conducted to evaluate the accuracy, response, and proportionality of both the EFMs and PFDs. The main PFD comparison was then conducted with one gasoline direct injection vehicle over different combinations of FTP and US06 tests. Additional tests were conducted to evaluate sources of contamination (PM absorption and desorption) to the raw exhaust transfer line and sample system walls for CVS and PFD systems. These tests were performed on three commercially available PFDs (Horiba, Sierra, and AVL) and four EFMs (Sick, Horiba, Sierra, and AVL).
总页数：	9
报告类型：	科技报告