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Title: Modeling On-Road Particle Number Emissions from a Hybrid Diesel–Electric Bus:
Exploratory Econometric Analysis
Accession Number: 01042526
Record Type: Component
Record URL: Availability: Transportation Research Board Business Office 500 Fifth Street, NW Find a library where document is available Abstract: The purpose of this econometric analysis is to model the concentration of particle number emissions from a hybrid diesel–electric bus in terms of operating characteristics. Particle number concentrations are modeled instead of particle mass, and the emissions are recorded by using on-board instrumentation in real-world driving conditions. The operating characteristics included in the final models are two engine parameters (fuel rate and engine speed) and two vehicle parameters (velocity and acceleration). The emissions data possess properties that frequently cause problems in regression analysis: nonstationarity, multicollinearity, heteroscedasticity, and autocorrelation. Methods for overcoming and minimizing the effects of these properties are implemented. Aggregation is used to reduce the nonstationarity of the data, and one of the potential operating characteristics is removed to decrease the multicollinearity. The Newey–West autocorrelation consistent covariance estimator is implemented by using ordinary least squares to produce a model that accounts for heteroscedasticity and autocorrelation, without requiring assumptions to be made about the structure of the model disturbances. A first-order autoregressive process is used with feasible generalized least squares as a comparative model. The two models have similar coefficients, fit, and predictive capability. However, the models are specific in scope to typical freeway driving conditions. In future studies, the researchers anticipate applying econometric analysis to model particle number emissions among different routes, bus technologies, aftertreatments, and atmospheric conditions.
Monograph Title: Monograph Accession #: 01083340
Language: English
Authors: Sonntag, Darrell BruceGao, H OliverHolmen, Britt APagination: pp 40-48
Publication Date: 2007
ISBN: 9780309104371
Media Type: Print
Features: Figures
(6)
; References
(10)
; Tables
(5)
TRT Terms: Uncontrolled Terms: Subject Areas: Data and Information Technology; Energy; Environment; Highways; Public Transportation; Vehicles and Equipment; I15: Environment; I91: Vehicle Design and Safety
Files: TRIS, TRB, ATRI
Created Date: Feb 8 2007 7:50PM
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