Thermally Stable Pt/Rh Catalysts

Zhang, G.; Hirota, T.; Hosokawa, Y; Muraki, Masayoshi

doi:10.4271/972909

Cited by 7 publications

(1 citation statement)

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“…The deposition techniques of PGM especially in relevance to the ceria particles position are well known to enhance catalytic performance [ 171 ]. Depending on the precious metal and the precious metal content, different amounts and/or compositions of washcoat are necessary to keep the chemical balance between active sites and surface area in the desired range [88].…”

Section: A Short Reference To the Scope And The Aims Of The Applicationsmentioning

confidence: 99%

Development and application of a computer aided engineering methodology supporting the design optimization of automotive exhaust treatment systems

Konstantas¹

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O p t i m i z a t i o n o f A u t o m o t i v e E x h a u s t T r e a t m e n t S y s t e m sTHESIS submitted in partial fulfillment of the requirements for the degree of D o c t o r o f P h i l o s o p h y i n M e c h a n i c a l E n g i n e e r i n g of the D e p a r t m e n t o f M e c h a n i c a l a n d I n d u s t r i a l E n g i n e e r i n g -3 - Since the core of almost every automotive exhaust aftertreatment system is some kind of catalytic converter, intensive research activity is devoted to the various scientific and technical aspects of catalytic technology. These aspects vary from practical research on new materials and novel techniques to improve catalyst microstructure, to theoretical contributions of detailed descriptions of chemical phenomena inside the converters and proposals of mechanistic reaction schemes.Nevertheless, the extremely high efficiencies that are expected from any modern catalyst cannot be attained without simultaneously optimizing aftertreatment device performance, engine design and the control system that drives the whole system. Thus, from a mechanical engineer's point of view, the exhaust treatment complexity is expressed as a strong interaction between these three fields: powertrain operation, engine management characteristics and exhaust treatment device operation.In general, the composition of exhaust gas depends on the engine type, the operating point of the engine, the ambient temperature, the transmission system and miscellaneous characteristics of each system. Thus, the engine management holds a key role in the behavior of the catalytic converter, since it affects both its input as well as the temperature range under which it operates. Moreover, exhaust line design, involving exhaust manifold heat capacity, insulated pipes and positioning of the devices, is strongly connected with the catalytic converter operation. Furthermore, catalysts with the same chemical composition may behave quite differently, depending on the actual procedures that were employed during catalyst preparation.The complexity of the automotive exhaust treatment systems quickly became apparent in the industry. Mathematical modeling tools are continuously developed, in order to complement the experimental efforts and provide guidance for areas that needed improvement. In the last 30 years, many models have appeared in the literature [2] . Their approaches and their scope were diverse, but in general they were rather focused on the individual devices than on the whole aftertreatment system. -6 -Specifically for the catalytic converter modeling: most kinetic studies so far resulted in models that are valid for the specific combination of engine and catalyst status at that moment (usually fresh catalysts). Although valuable for a specific engineering problem, such modeling results could only partially be extended in different systems, and only with great caution. Indeed, successful extension of the results of a specific case to another one is rare in the literature [1] . As a characteristic example...

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Section: A Short Reference To the Scope And The Aims Of The Applicationsmentioning

confidence: 99%