A phenomenological model for soot formation and oxidation in direct-injection diesel engines

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:186851

Li, X ^[1]; Wallace, J S ^[2]

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1. National Research Council Canada, Ottawa, Ontario (Canada)
2. Univ. of Toronto, Ontario (Canada)

The concentration of carbonaceous particulate matter in the exhaust of diesel engines depends on the rates of formation and oxidation of soot in the combustion chamber. Soot forms early in the combustion process when local fuel-rich areas exist, whereas soot oxidation occurs later when more air is entrained into the fuel spray. Based on this understanding, a phenomenological combustion model is established. In the model, the cylinder volume is divided into four zones: a rich fuels spray core, a premixed-burning/burned gas zone, a mixing controlled burning zone and a lean air zone. Soot formation takes place in the mixing controlled burning zone where the local C/O ratio is above the critical value. Soot oxidation occurs in the premixed-burning/burned gas zone as air is entrained. By using a quasi-global chemical reaction scheme, the oxidation of soot particles by different species can be investigated. The model predictions were compared with the measured cylinder pressure and exhaust emission data. A reasonably good agreement was observed. A number of oxidation rates cited in the literature were tested in this model. It was found that the oxidation rate established by Nagle and Strickland-Constable adequately accounted for the apparent soot oxidation rate under diesel engine conditions. 37 refs., 10 figs., 3 tabs.

• OSTI ID: 186851
• Report Number(s): CONF-9510144--; ISBN 1-56091-707-5
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
COMBUSTION KINETICS
DIESEL ENGINES
OXIDATION
SOOT
SYNTHESIS