Dependence of pollutant emission factors and fuel consumption on driving conditions and gasoline vehicle types

Abstract

Vehicle types, technologies, and driving conditions are key factors affecting emission factors and fuel consumption. In this study, we measured the hydrocarbon (HC), carbon monoxide (CO), and nitrogen oxide (NOx) emission factors, and fuel consumption of vehicles with a (1) carburetor (CVs), (2) multipoint injection technology and three-way catalyst (MTVs), and (3) multipoint injection technology, three-way catalyst, and exhaust gas recirculation device (MTEVs) under real driving conditions using an OBS-2200 portable emission measurement system. The results showed that both the distance- and fuel-based HC, CO, and NOx emission factors of CVs were 2.7–6.6 times higher than those of MTVs and MTEVs. The average incomplete fuel conversion rates (IFCRs) of CVs were 3.8 and 4.4 times higher than those of MTVs and MTEVs, respectively. The molar ratios of the CO/HC pollutants were 7.6, 5.6, and 2.8 for CVs, MTVs, and MTEVs. Furthermore, the correlation between the vehicle-specific power and fuel consumption rate was significant. The exhaust gas recirculation (EGR) system could improve the fuel combustion efficiency and reduce vehicle emissions, particularly under high-speed and acceleration conditions.