AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Online Analysis of Secondary Organic Aerosol Emissions from a Flexi-Fuel Gasoline Engine Operated with Gasoline-Ethanol Blends
JORMA JOKINIEMI, Mika Ihalainen, Petri Tiitta, Miika Kortelainen, Martin Sklorz, Benjamin Stengel, Laarnie Müller, Stefan Stanglmaier, Vesta Kohlmeier, Gert Jakobi, Pasi Yli-Pirilä, Anni Hartikainen, Thorsten Streibel, Ralf Zimmermann, Olli Sipppula, University of Eastern Finland, Kuopio, Finland
Abstract Number: 298 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Automotive engines generate substantial fine particle emissions to ambient air, which are known to induce globally significant adverse health and climate effects. It has been recently shown that while gasoline engines generate relatively low primary particle emissions, they generate substantial secondary organic aerosol emissions (Tkacik et al., 2014), an emission component which is not currently considered in legislation.
In this work, a recently developed photochemical flow tube reactor (PEAR) was applied to study the photochemical aging of bioethanol and gasoline fueled car engine emissions. The reactor flow dynamics were optimized based on CFD modeling. It is constructed from stainless steel tube (Ø 34 cm) with 254 nm UV lamps assembled at the inner walls. Ozone and water vapor are added into the reactor to produce OH radicals via photolytical decomposition of O3. The OH exposure times were estimated by measuring D9-butanol gas decay with PTR-MS during the experiments. Ozone concentration and lamp intensities were varied to achieve different OH exposure times, ranging from 1 to 8 days of atmospheric age.
The engine applied for the experiments was EURO5 AUDI turbo charged flexi-fuel gasoline engine and two different gasoline-ethanol fuel mixes (E5 and E85) were used. Both the New European Driving Cycle (NEDC) and selected steady state conditions were used in the emission study. Particulate emissions were measured using HR-AMS, SMPS and Aethalometer.
Using of E85 bioethanol fuel had both lower primary particle and SOA concentrations than E5 gasoline. Increasing of OH exposures gradually increased aerosol odixation states and SOA formation, reaching SOA/POA ratios of 4 and 5 at the highest OH exposure (8 days) for E5 and E85, respectively.