This paper demonstrates vehicle emission factor measurement using an on-board, on-road system and examines the effects of ambient temperature on those emission factors. Vehicle operating parameters, fuel consumption and emissions were measured on-road using a portable measurement system designed for ease of use with range of vehicles, drivers and driving situations. The results reported here come from repeated trips over a 17.4 km urban / suburban route with a particular driver and vehicle. As such, the emission factors developed here do not represent the current on-road fleet. However, they show the strong influence of actual operating conditions (particularly ambient temperature) and of the vehicle control system's response to non-standard conditions. This leads to an appreciation for on-road testing as a means to illustrate vehicle emission behaviour in real conditions and to highlight conditions which may require more detailed study. A series of trips over a one year period, (with an ambient temperature range of -25 to +20 deg C), were analysed to develop emission factor models with one, two or three emission factors. The results emphasize the inadequacy of using a single 'grams-per-mile' emission factor to model emissions of vehicle operating over a range of trip lengths and ambient conditions. A two-emission-factor model provides adequate information to accommodate short trip lengths and a three-emission-factor model can fit the detailed behaviour but is generally not required. The emission factors for the test vehicle were found to correlate with ambient temperature allowing the characterization of emission behaviour for cold start applications. Comparing the cold-start pre- and post-catalyst light-off emission factors, it was determined that typical magnitude increases of 100, 60 and 10 were calculated for HC, CO and NO(x) respectively over the temperature range of +20 deg C to -26 deg C.
Quantifying vehicle emission factors for various ambient conditions using an-road, real-time emissions system
2003
13 Seiten, 13 Bilder, 5 Tabellen, 32 Quellen
Aufsatz (Konferenz)
Englisch
Fahrzeugmotor , Fahrverhalten , Schadstoffemission , Umgebungseinfluss , Echtzeitsystem , Umgebungstemperatur , Betriebsdaten (technische Parameter) , Kraftstoffverbrauch , Steuerungs- und Regelungssystem , mathematisches Modell , Kennwert , Kaltstart , Kohlenwasserstoff , Kohlenmonoxid , Stickstoffoxid , Kraftwagen , Messung im Einsatz , Messtechnik
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