AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Impact of Exhaust Aftertreatment on Primary and Secondary Particulate Emissions of a Non-Road Diesel Engine
PANU KARJALAINEN, Leonidas Ntziachristos, Pauli Simonen, Kimmo Teinilä, Hilkka Timonen, Henna Saveljeff, Mika Lauren, Matti Happonen, Pekka Matilainen, Teuvo Maunula, Jukka Nuottimäki, Topi Rönkkö, Jorma Keskinen, Tampere University of Technology
Abstract Number: 265 Working Group: Combustion
Abstract The new Stage V for non-road mobile machinery (NRMM) calls for the introduction of diesel particle filters (DPFs) as a result of the decision to regulate particle number on top of particle mass. Stage V goes several steps beyond Stage IV, for which only deNOx aftertreatment was enough to reach required emission levels. With Stage V, understanding the potential of different aftertreatment technologies to bring real world reductions in NOx and PM emissions is required.
Recent research suggests that vehicles contribute to atmospheric PM concentrations not just through their direct (primary) PM emissions measured at the tailpipe but also through photo-oxidation and gas-to-particle processes of initially gaseous exhaust components (secondary PM). To understand the health and environmental effects of exhaust emissions, both primary particulate emission and secondary formation need to be characterized. In this study we used a comprehensive set of measurements to characterize both particulate types produced by a modern nonroad engine equipped with the most relevant exhaust aftertreatment systems.
Two fuel grades, one typical diesel fuel oil (DFO) and one so-called renewable diesel – hydro-treated vegetable oil (HVO) were used in the testing. Primary emissions were measured following raw exhaust sampling with a porous tube dilutor. Secondary particle formation was initiated using a Potential Aerosol Mass (PAM) chamber to simulate secondary aerosol formation in the atmosphere.
Our results suggest that advanced aftertreatment seems to satisfactorily decrease both primary and secondary PM emissions. In particular DPF efficiency is above 90% for both particle types. A well operating selective catalytic reduction (SCR), combined with a diesel oxidation catalyst, also leads to significant PM and NOx reductions. Excess ammonia events (NH3 slip) may lead to disproportional increase of secondary PM and have to be carefully controlled and avoided.