Behavior of automobile exhaust catalysts with cycled feedstreams

Taylor, Kathleen C.; Sinkevitch, Robert M.

doi:10.1021/i300009a012

Cited by 54 publications

(16 citation statements)

References 4 publications

(13 reference statements)

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“…Since the beginning of the previous decade, it has been recognized that the three-way catalyst e$ciency is signi"cantly a!ected when the composition of the feed gas is oscillating with di!erent amplitudes and frequencies (Shulman et al, 1982;Herz et al, 1983;Taylor and Sinkevitch, 1983;Schlatter et al, 1983;Matsunaga et al, 1987). This behavior is mainly attributed to the ability of some washcoat components to be periodically oxidized and reduced depending on the exhaust gas redox environment.…”

Section: Introductionmentioning

confidence: 99%

Modeling dynamic phenomena in 3-way catalytic converters

Koltsakis

Stamatelos

1999

Chemical Engineering Science

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Mathematical modeling of 3-way catalytic converter (3WCC) operation is increasingly employed in automotive catalyst and converter systems optimization. The majority of the models employed in this direction employ a &quasi-steady' approach in the reaction kinetics computations. This approach is useful in predicting real-world performance of the catalyst. However, certain improvements, that are produced by the application of specially tuned redox oscillations, can not be predicted. This paper presents an approach embodying certain types of dynamic phenomena into an existing 3-WCC quasi-steady model. The dynamic model developed according to this approach is validated against literature data and results from experimental investigations. It is con"rmed, that the catalyst behavior under dynamic exhaust composition conditions signi"cantly di!ers from what is predicted under the quasi-steady-state assumption. More speci"cally, oxygen storage and the transient character of water gas shift reaction are shown to a!ect dynamic behavior. The results of this investigation encourage further application of mathematical modeling in areas like lambda control strategy optimization, which lied beyond the scope of traditional 3WCC models.

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Section: Introductionmentioning

confidence: 99%

Modeling dynamic phenomena in 3-way catalytic converters

Koltsakis

Stamatelos

1999

Chemical Engineering Science

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“…Large rate enhancements through cycling were demonstrated for CO oxidation over noble metal catalysts [53] and for the ammonia synthesis over ruthenium and osmium [ 1,71 ]. The presence of unintentional periodic operation in the noble metal catalytic mufflers used for automotive exhausts was identified and studied with conflicting results on the benefits of this mode [72,73]. During the 1980's, the emphasis in experimental studies began to shift towards complex reactions and questions of selectivity.…”

Section: Literature On Periodic Operationsmentioning

confidence: 99%

Periodic operation of catalytic reactors—introduction and overview

1995

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“…4,5 However, as real-world emissions are mainly transient, they show deviations there. [6][7][8][9] Thus, another part of global reaction models include oxygen storage and release reactions (oxidation and reduction of the ceria located in the washcoat) to improve model prediction under transient conditions. [10][11][12][13][14] These models are validated both under steady-state tests and in legislative driving cycles, and show good accuracy, which makes them suitable for optimization of TWC design.…”

Section: Introductionmentioning

confidence: 99%

A fleet-prediction oriented catalyst model for highly transient driving in cold and hot mode conditions

Weilenmann

Tsinoglou

2012

International Journal of Engine Research

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Various models for simulating catalytic converters are given in the literature. They deal with a wide range of different aspects. In addition to the type of catalytic converter (three-way catalytic converter, diesel oxidation catalytic converter, etc.), the aspect of complexity versus accuracy and speed can be tackled using different approaches. Moreover, the desired use has an influence on the model structure: optimization of catalyst design or prediction of emissions from real-world traffic situations or optimization of air-fuel ratio control?The model described here has been developed to predict emissions in arbitrary real-world driving patterns, both for hot driving as well as for cold-start situations. As these tests mainly last over 30 minutes (real time), the calculation effort should be small. The model should be easy to parameterize, as it should be applicable to vehicles from traffic.A model with a reduced set of chemical reactions has been developed with a particular focus on the thermal balance for cold-start cycles. Its outputs are the pollutant emissions at the tailpipe if the emissions, exhaust mass flow and temperature from the engine are given. It is applied to three-way catalytic converters. It models the chemical phenomena almost entirely based on oxygen storage and release reactions, which dominate highly transient situations. The model has been validated against a large database of measured driving cycles, carried out using different types of cars. It presents an acceptable degree of correlation between simulated and experimental results.

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Behavior of automobile exhaust catalysts with cycled feedstreams

Cited by 54 publications

References 4 publications

Modeling dynamic phenomena in 3-way catalytic converters

Modeling dynamic phenomena in 3-way catalytic converters

Periodic operation of catalytic reactors—introduction and overview

A fleet-prediction oriented catalyst model for highly transient driving in cold and hot mode conditions

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