Estimation of Transport Efficiency for Brake Emissions Using Inertia Dynamometer Testing 2018-01-1886
Even though there is vast literature and peer-reviewed methods to estimate losses during aerosol sampling, there are no current models for laboratory measurement of brake emissions. The paper presents calculation for transport losses using three different models (Particle Loss Calculator from the Max Planck Institute, SAE AIR6504 for calculation of non-volatile particulate matter penetration, and the AeroCalc from the United States Center for Disease Control and Prevention). In addition to explaining the main elements and boundary conditions for each model, the results (using numerical examples) include additional factors to better estimate losses during: a) conceptual design and assessment of the feasibility of the initial system layout with emphasis on the influence of duct design, dimensions and isokinetics; b) validation (prior to actual testing) of a given system; and c) actual testing, with proper corrections for air humidity, elevation, and poly-disperse coagulation. The methods proposed are agnostic to the brake dynamometer design, brake type or size, or the specific Particle Measurement System (PMS). In order to cover meaningful ranges for duct size, airflow in the duct, and airflow in the sampling lines, the assessments follows a Renard series (ISO 3:1973 Preferred numbers -- Series of preferred numbers). This work contributes to the industry efforts (led by the JRC on behalf of the UNECE/GRPE/PMP) to develop a robust and harmonized set of test methods and measurements to characterize, and report automotive brake emissions using inertia dynamometer testing.
Carlos Agudelo, Ravi Teja Vedula, Tyler Odom