Research Projects

This project characterizes the formation and growth of ultrafine particulates in the emissions from diesel engines under controlled but real-world conditions of dilution. A Class 8 tractor and trailer is operated on a dynamometer over standard driving cycles inside a large wind tunnel. Emissions are measured in the wind tunnel downstream of the vehicle with a variety of equipment including particle counting and sizing instruments, aerosol scattering and absorption coefficient measurements, criteria gas monitors, and toxic gas samplers. To investigate the development of the plume, the emissions are measured at multiple transverse and axial locations ranging from 0 to 180 feet downwind. The results will be used to evaluate the relationship between emissions measured using conventional constant volume sampling or partial flow sampling systems with emissions experienced under real-world dilution conditions such as near roadways. Measurement of the optical properties of diesel emissions will provide direct evidence for the investigation of climatic impact of diesel particles.