AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Exhaust PM Measurement Using Low Cost Monitors: What They Measure and How Well
MATTI MARICQ, Ford Motor Company
Abstract Number: 70 Working Group: Combustion
Abstract With world wide tightening of engine exhaust PM emissions standards, PM measurement is becoming pervasive throughout the development, testing, and certification phases of motor vehicle production, and is extending as well to on-board diagnostics. At the same time we have seen considerable growth in the variety of instruments and methods to measure PM emissions. Well known devices, such as the scanning mobility particle sizer, electrical low pressure impactor, and aerosol particle mass analyzer are beneficial in the research phase to provide detailed characterization of exhaust PM. But they are less suited for routine test cell operation where simpler less costly devices are needed for long uninterrupted operation harsh environments. High end instruments, such as the Dekati Mass Monitor and Photoacoustic Soot Sensor are available for test cell environments, but their cost and size limits their widespread use.
This work examines three particle monitors: Dust Trak, Pegasor PPS, and DiSC. The intent is not to be comprehensive, but rather to contrast three different strategies aimed at quantifying PM emissions: light scattering, escaping charge, and diffusion size classification. We compare these monitors using both vehicle emissions tests and controlled laboratory aerosols. These monitors show good correlations with the transient changes in PM along a drive cycle, as also previously observed for the Dust Trak in EPA's Kansas City study. However, closer examination with laboratory aerosols reveals significant differences in how these monitors respond to the size and composition of the particles. These responses in turn tell us how robust the PM monitors are to changes in the nature of exhaust PM across different fuels and engine technologies.