In-use vehicle fuel consumption and emissions functions measurement

Fundamental accomplishment was achieved by development of an on-board and in-use fuel consumption and emissions measurement system adapted for easy transition from vehicle to vehicle. Instantaneous mass flow rates of fuel and emissions were measured and recorded by an ECM OBD-II scanner, a mass air flow meter, two emissions analyzers and a laptop computer on five typical mid-life vehicles representative of a significant fraction of the on-road fleet. From repeated tests in urban, highway and aggressive driving situations, on-road fuel consumption functions were developed to quantify the fuel economy and greenhouse gas CO2 emission impact of vehicle, road and traffic control changes. Comprehensive emission factors analysis for HC, CO and NOx was also illustrated to highlight that vehicle power-based emission factor could represent the influences from wide varieties of vehicle power demand and acceleration driving profiles. A basic in-use power-based model was developed for use in estimating cumulative fuel consumption and tailpipe emissions for vehicles experiencing real-world driving conditions with significant differences from the standard test sequences.