AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
A New Device for Measuring Number Concentration of Solid Particulate Matter
AARON AVENIDO, Jason Johnson, Brian Osmondson, Hans-Georg Horn, TSI Incorporated
Abstract Number: 339 Working Group: Instrumentation and Methods
Abstract The significant reduction of particulate matter (PM) emissions from diesel engines since the introduction of diesel particulate filters (DPF) has made conventional mass based emissions measurement techniques impractical due to their inherently low sensitivity. To measure reduced PM emissions, a portable instrument capable of measuring the total number concentration of solid particles resulting from combustion sources has been developed.
The TSI Model 3795 Nanoparticle Emission Tester (NPET) consists of a sample dilution and conditioning system that removes condensation and large particles (greater than 1 micrometer) from the sample using a water trap and cyclone. Volatile particles are then removed using a built-in catalytic stripper (CS) and the resulting number concentration of solid particles is measured using an isopropanol based condensation particle counter (CPC). The instrument described here is capable of measuring number concentration from less than 1,000 to 5,000,000 particles per cubic centimeter; allowing for the measurement of solid PM number concentrations from engine configurations with, and to some extent, without DPF.
The built in CS volatile particulate removal efficiency has been determined to be greater than 99% by measuring the number concentration of 30nm geometric mean diameter tetracontane particles upstream of the CS using a TSI 3025A CPC and downstream of the CS using the built in isopropanol CPC of the NPET.
The instrument’s built in catalytic stripper and CPC have also been characterized by measuring exhaust particle emissions from a modern GM 2.0l turbocharged diesel engine and comparing NPET measurements to particulate size distributions with and without CS gathered by a TSI SMPS. In addition, NPET measured solid PM number concentrations have been compared to those as measured by a TSI 3790A engine exhaust CPC. The NPET performance characterization and comparison to 3790A CPC will be presented.