Quantifying the Emission Benefits of Opacity Testing and Repair of Heavy-Duty Diesel Vehicles

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• 作者：Robert L. McCormick ; Michael S. Graboski ; Teresa L. Alleman ; Javier R. Alvarez ; and K. G. Duleep
• 刊名：Environmental Science & Technology
• 出版年：2003
• 出版时间：February 1, 2003
• 年：2003
• 卷：37
• 期：3
• 页码：630 - 637
• 全文大小：93K
• 年卷期：v.37,no.3(February 1, 2003)
• ISSN：1520-5851

文摘

The objective of this study was to begin to quantify thebenefits of a smoke opacity-based (SAE J1667 test) inspectionand maintenance program. Twenty-six vehicles exhibitingvisible smoke emissions were recruited: 14 pre-1991vehicles and 12 1991 and later model year vehicles. Smokeopacity and regulated pollutant emissions via chassisdynamometer were measured, with testing conducted at1609 m above sea level. Twenty of the vehicles were thenrepaired with the goal of lowering visible smoke emission,and the smoke opacity testing and pollutant emissionsmeasurements were repeated. For the pre-1991 vehiclesactually repaired, pre-repair smoke opacity averaged 39%and PM averaged 5.6 g/mi. NO_x emissions averaged 22.1g/mi. After repair, the average smoke opacity had declinedto 26% and PM declined to 3.3 g/mi, while NO_x emissionsincreased to 30.9 g/mi. For the 1991 and newer vehiclesrepaired, pre-repair smoke opacity averaged 59% and PMaveraged 2.2 g/mi. NO_x emissions averaged 12.1 g/mi.After repair, the average opacity had declined to 30% andPM declined to 1.3 g/mi, while NO_x increased slightly to14.4 g/mi. For vehicles failing the California opacity test at>55% for pre-1991 and >40% for 1991 and later modelyears, the changes in emissions exhibited a high degreeof statistical significance. The average cost of repairs was$1088, and the average is very similar for both the pre-1991 and 1991+ model year groups. Smoke opacity wasshown to be a relatively poor predictor of driving cycle PMemissions. Peak CO or peak CO and THC as measuredduring a snap-acceleration were much better predictorsof driving cycle PM emissions.