Vehicle Specific Power Approach to Estimating On-Road NH₃ Emissions from Light-Duty Vehicles

Abstract

NH3 emissions from motor vehicles have been the subject of a number of recent studies due to their potential impact on ambient particulate matter (PM). Highly time-resolved NH3 emissions can be measured and correlated with specific driving events utilizing a tunable diode laser (TDL). It is possible to incorporate NH3 emissions with this new information into models that can be used to predict emissions inventories from vehicles. The newer generation of modal models are based on modal events, with the data collected at second-by-second time resolution, unlike the bag-based emission inventory models such as EMFAC and MOBILE. The development of an NH3 modal model is described in this paper. This represents one of the first attempts to incorporate vehicle NH3 emissions into a comprehensive emissions model. This model was used in conjunction with on-road driving profiles to estimate the emissions of SULEV, ULEV, and LEV vehicles to be 9.4 +/- 4.1, 21.8 +/- 5.2, and 34.9 +/- 6.0 mg/mi, respectively. We also implement this new NH3 model to predict and evaluate the NH3 emission inventory in the South Coast air basin (SoCAB).

Comparison of Flexible Fuel Vehicle and Life-Cycle Fuel Consumption and Emissions of Selected Pollutants and Greenhouse Gases for Ethanol 85 Versus Gasoline

“…38 -40 The VSP-based approach has been used in emissions modeling for conventional light-and heavy-duty vehicles. 38,40,[41][42][43] However, less attention has been devoted to FFVs because of a lack of second-by-second data.…”

Trends in on-road vehicle emissions of ammonia

“…Durbin et al (2002) reported an average ammonia emission factor of 34 mg km -1 for 39 recruited gasoline-powered vehicles on the Federal Test Procedure (FTP), with increased ammonia emissions on more aggressive driving cycles. In related efforts, Huai et al (2003 and2005) showed that ammonia emissions are primarily generated during acceleration events for modern technology vehicles. Recent laboratory dynamometer studies also showed that vehicles equipped with more advanced emissions control technologies demonstrated better ammonia emission control behavior (Durbin et al, 2002;Huai et al, 2003 and2005).…”

“…In related efforts, Huai et al (2003 and2005) showed that ammonia emissions are primarily generated during acceleration events for modern technology vehicles. Recent laboratory dynamometer studies also showed that vehicles equipped with more advanced emissions control technologies demonstrated better ammonia emission control behavior (Durbin et al, 2002;Huai et al, 2003 and2005).…”

Comparison of on-road emissions for B-0, B-10, and B-20 in transit buses

“…VSP is the instantaneous power per unit mass of the vehicle. Huai et al (2005) indicates that the advantages of using VSP as an independent variable for studying hot stabilized emissions are that specific power can be directly measured, it captures most of the dependence of emissions on engine operating parameters, and certification driving cycles can be specified in VSP.…”