Simulation of the Unsteady Gas Flow through a Three-way Automotive Catalyst

Geoffrey McCullough, Martin McMackin, A.P.N. McDowell

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


This paper describes a model of a 1.8-litre four-cylinder four-stroke gasoline engine fitted with a close-coupled three-way catalyst (TWC). Designed to meet EURO 3 emissions standards, the engine includes some advanced emission control features in addition to the TWC, namely: variable valve timing (VVT), swirl control plates, and exhaust gas recirculation (EGR). Gas flow is treated as one-dimensional (1D) and unsteady in the engine ducting and in the catalyst. Reflection and transmission of pressure waves at the boundaries of the catalyst monolith are modelled. In-cylinder combustion is represented by a two-zone burn model with dissociation and reaction kinetics. A single Wiebe analysis of measured in-cylinder pressure data is used to determine the mass fraction burned as a function of crank angle (CA) at each engine speed. Measured data from steady-state dynamometer tests are presented for operation at wide open throttle (WOT) over a range of engine speeds. These results include CA-resolved traces of pressure at various locations throughout the engine together with cycle-averaged traces of gas composition entering the catalyst as indicated by a fast-response emissions analyser. Simulated engine performance and pressure wave action throughout the engine are well validated by the measured data.
Original languageEnglish
Pages (from-to)1175-1185
Number of pages11
JournalSAE 2006 Transactions - Journal of Fuels and Lubricants
Volume115 (4)
Publication statusPublished - Sep 2005

Bibliographical note

Journal Name: 9780768018363

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