Prediction of In-Use Emissions of Heavy-Duty Diesel Vehicles from Engine Testing

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• 作者：Janet Yanowitz ; Michael S. Graboski ; and Robert L. McCormick
• 刊名：Environmental Science & Technology
• 出版年：2002
• 出版时间：January 15, 2002
• 年：2002
• 卷：36
• 期：2
• 页码：270 - 275
• 全文大小：126K
• 年卷期：v.36,no.2(January 15, 2002)
• ISSN：1520-5851

文摘

A model of a heavy-duty vehicle driveline with automatictransmission has been developed for estimating engine speedand load from vehicle speed. The model has beenvalidated using emissions tests conducted on three dieselvehicles on a chassis dynamometer and then on theengines removed from the vehicles tested on an enginedynamometer. Nitrogen oxide (NO_x) emissions wereproportional to work done by the engine. For two of theengines, the NO_x/horsepower(HP) ratio was the same on theengine and on the chassis dynamometer tests. For thethird engine NO_x/HP was significantly higher from the chassistest, possibly due to the use of dual engine maps. Theengine certification test generated consistently less particulatematter emissions on a gram per brake horsepower-hourbasis than the Heavy Duty Transient and Central BusinessDistrict chassis cycles. A good linear correlation (r² =0.97 and 0.91) was found between rates of HP increaseintegrated over the test cycle and PM emissions for boththe chassis and the engine tests for two of the vehicles.The model also shows how small changes in vehicle speedscan lead to a doubling of load on the engine. Additionally,the model showed that it is impossible to drive a vehiclecycle equivalent to the heavy-duty engine federal testprocedure on these vehicles.