Speciation of Nitrogen Compounds in the Tailpipe Emissions from a SI Car under Real World Driving Conditions

Abstract

The tailpipe exhaust emissions were measured using a EURO4 emissions compliant SI car equipped with on-board measurement systems such as a FTIR system for gaseous emission, a differential GPS for velocity, altitude and position, thermal couples for temperatures, and a MAX fuel meter for transient fuel consumption. Various nitrogen species emissions (NO, NO2, NOx, NH3, HCN and N2O) were measured at 0.5 Hz. The tests were designed and employed using two real world driving cycles/routes representing a typical urban road network located in a densely populated area and main crowded road. Journeys at various times of the day were conducted to investigate traffic conditions impacts such as traffic and pedestrian lights, road congestion, grade and turning on emissions, engine thermal efficiency and fuel consumption. The time aligned vehicle moving parameters with Nitrogen pollutant emission data and fuel consumption enabled the micro-analysis of correlations between these parameters. The average data for journeys such as thermal efficiency, emissions and fuel consumption were determined. Traffic events and vehicle transient movements' impact on emissions were studied. Engine power output has been calculated by using vehicle specific power (VSP). The analysis result of tailpipe emissions and their relation to real world driving profile improved understanding of urban area nitrogen compound emissions, which will be useful for controlling of urban air quality.