Solid Particle Number and Mass Emissions from Lean and Stoichiometric Gasoline Direct Injection Engine Operation

Noah Bock, Joonho Jeon, David B Kittelson, William Northrop

Research output: Contribution to journalConference articlepeer-review

17 Scopus citations


In this work, engine-out particle mass (PM) and particle number (PN) emissions were experimentally examined from a gasoline direct injection (GDI) engine operating in two lean combustion modes and one stoichiometric mode with a fuel of known properties. Ten steady state operating points, two constant speed load steps, and an engine cold start were examined. Results showed that solid particles emitted from the engine under steady state stoichiometric conditions had a uniquely broad size distribution that was relatively flat between the diameters of 10 and 100 nm. In most operating conditions, lean homogenous modes can achieve lower particle emissions than stoichiometric modes while improving engine thermal efficiency. Alternatively, lean stratified operating modes resulted in significantly higher PN and PM emissions than both lean homogeneous and stoichiometric modes with increased efficiency only at low engine load. Stoichiometric load steps showed minimal soot emissions while ash-mode emissions spike dramatically due to oil consumption caused by piston ring adjustment. Correlation of PN to PM for steady state stoichiometric cases was in good agreement with that reported from multiple prior studies for both diesel and stoichiometric GDI engines. However, the lean cases resulted in higher PN to PM ratios indicating more small particles per unit mass. High ash particle concentration, especially in lean operation illustrates that oil control is important for mitigating impacts on downstream gasoline particulate filters (GPF) from which ash particles are cannot be removed during filter regeneration. Further research is necessary to elucidate the origin and composition of sub-23 nm particles from GDI engines and their effect on aftertreatment technology if lean homogeneous modes are to be employed.

Original languageEnglish (US)
JournalSAE Technical Papers
StatePublished - 2018
Event2018 SAE World Congress Experience, WCX 2018 - Detroit, United States
Duration: Apr 10 2018Apr 12 2018

Bibliographical note

Funding Information:
This material is based upon work supported by the Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE), under Award Number DE-EE0007217.

Publisher Copyright:
© 2018 SAE International. All Rights Reserved.


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