AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Implications for the Sampling System in Extending Automotive Particle Regulations Below 23 nm. First Results of the DownToTen Project
PANU KARJALAINEN, Jorma Keskinen, Markus Bainschab, Alexander Bergmann, Athanasios Mamakos, Jonathan Andersson, Barouch Giechaskiel, Leonidas Ntziachristos, Zissis Samaras, Tampere University of Technology
Abstract Number: 255 Working Group: Instrumentation and Methods
Abstract We present the objectives, the impacts and first experimental results of the Horizon 2020 Green Vehicle project “DownToTen”. This project is developing a robust methodology that will enhance the regulatory approach towards particle number emissions in the sub-23 nm region. The focus is on the newest generations of direct injection gasoline and diesel engines under real world conditions. Based on detailed investigations of the nature and characteristics of these particles, DownToTen is evaluating a variety of sub-23 nm PN measurement instruments and sampling approaches, using rigorous criteria under conditions of challenging aerosol from a variety of sources. The objective is a PN-Portable Emission Measurement System (PEMS) demonstrator with high efficiency in determining PN emissions of current and future engine technologies in the real world, including the sub-23 size fraction.
The first direction of research is to design a sampling system with minimized losses for nanometre-sized particles and the potential to be used for on-board measurements. Important factors like robustness against artefacts (re-nucleation, growth of subcut particles), losses of (solid) particles, storage/release effects of gas phase compounds are assessed in detail by multiphysical simulations and laboratory-scale experiments. Special attention is drawn to losses of secondary aerosol precursors within the primary dilution stage.
This paper presents the selection of the setup’s components (primary and secondary dilution stage, conditioning system, mixing elements, measurement devices) in order to meet the aforementioned criteria are based on experimental and theoretical data. The success in meeting these criteria is evaluated by comparing the sampling setup to commercial PMP reference system. Critical components are discussed in detail. CFD simulations and particle penetration optimizations based on the simulation results are also presented.