The Experts below are selected from a list of 6720 Experts worldwide ranked by ideXlab platform
J.w. Grizzle - One of the best experts on this subject based on the ideXlab platform.
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Fore-aft Oxygen Storage control
Proceedings of the 2002 American Control Conference (IEEE Cat. No.CH37301), 2002Co-Authors: G. Fiengo, J.a. Cook, J.w. GrizzleAbstract:This paper describes model-based, active control of an aftertreatment system for a spark ignition engine equipped with a three-way catalyst (TWC) and pre- and post-TWC Oxygen sensors. A controller is designed to manage the Oxygen Storage level in the TWC in order to maximize the simultaneous conversion efficiencies of oxides of nitrogen, NO/sub x/, unburned hydrocarbons, HC, and carbon monoxide, CO. Linear exhaust gas Oxygen sensors (UEGOs) are used to measure pre- and post-catalyst A/F. The pre-catalyst A/F measurement is assumed to be biased in addition to being corrupted by zero-mean noise, while the post-catalyst measurement is assumed to be only corrupted by zero-mean noise. A series controller configuration is adopted. The upstream controller provides relatively rapid response to disturbances, while the downstream controller uses an extended Kalman filter (observer) to estimate the relative Oxygen level. The estimated value of Oxygen Storage is then used to regulate the relative Oxygen level of the TWC to 50%. The performance and robustness of the proposed control system in the face of noise and model uncertainty are evaluated through extensive simulations.
Masahiro Sugiura - One of the best experts on this subject based on the ideXlab platform.
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Effect of ordered arrangement of Ce and Zr ions on Oxygen Storage capacity of ceria-zirconia solid solution
Journal of the Ceramic Society of Japan, 2020Co-Authors: Akihiko Suda, Kae Yamamura, Toshitaka Tanabe, Yoshio Ukyo, Hideo Sobukawa, Tsuyoshi Sasaki, Yasutaka Nagai, Masahiro SugiuraAbstract:The CeO 2 -ZrO 2 solid solution is the most important Oxygen Storage/release material for use in automobile catalysts. In particular, the ceria-zirconia solid solution with a pyrochlore structure exhibits the highest Oxygen Storage capacity (OSC). In this study, CeO 2 -ZrO 2 solid solutions containing Y 2 O 3 were synthesized and their OSCs were measured to clarify the influence of an ordered arrangement of Ce and Zr ions on the OSC. As a result of this study, it is concluded that an ordered arrangement of Ce and Zr ions markedly improves the OSC of CeO 2 -ZrO 2 solid solutions.
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Oxygen Storage materials for automotive catalysts ceria zirconia solid solutions
Catalysis Surveys From Asia, 2003Co-Authors: Masahiro SugiuraAbstract:This paper reviews progress in the development of Oxygen Storage materials for automotive exhaust catalysts. The research was mainly conducted as a study and development exercise in the author's laboratory in Japan.
G. Fiengo - One of the best experts on this subject based on the ideXlab platform.
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Fore-aft Oxygen Storage control
Proceedings of the 2002 American Control Conference (IEEE Cat. No.CH37301), 2002Co-Authors: G. Fiengo, J.a. Cook, J.w. GrizzleAbstract:This paper describes model-based, active control of an aftertreatment system for a spark ignition engine equipped with a three-way catalyst (TWC) and pre- and post-TWC Oxygen sensors. A controller is designed to manage the Oxygen Storage level in the TWC in order to maximize the simultaneous conversion efficiencies of oxides of nitrogen, NO/sub x/, unburned hydrocarbons, HC, and carbon monoxide, CO. Linear exhaust gas Oxygen sensors (UEGOs) are used to measure pre- and post-catalyst A/F. The pre-catalyst A/F measurement is assumed to be biased in addition to being corrupted by zero-mean noise, while the post-catalyst measurement is assumed to be only corrupted by zero-mean noise. A series controller configuration is adopted. The upstream controller provides relatively rapid response to disturbances, while the downstream controller uses an extended Kalman filter (observer) to estimate the relative Oxygen level. The estimated value of Oxygen Storage is then used to regulate the relative Oxygen level of the TWC to 50%. The performance and robustness of the proposed control system in the face of noise and model uncertainty are evaluated through extensive simulations.
Martin Votsmeier - One of the best experts on this subject based on the ideXlab platform.
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Impact of Test Conditions on the Oxygen Storage Capacity of Pd Loaded Cerium Zirconium Oxide
Topics in Catalysis, 2017Co-Authors: G. Keitl, Martin Votsmeier, J. Rink, Liesbet Jongen, Alexander Hofmann, A. Terfort, Jurgen GieshoffAbstract:An alternative method to determine the Oxygen Storage capacity (OSC) for powder materials is proposed in the current work. Dynamic and static OSC measurements were conducted at 510 °C using a thermally aged Pd loaded cerium zirconium oxide (30 wt% ceria, 1 wt% Pd). Particularly the influence of water and carbon dioxide in the gas feed on OSC determination was studied. The results demonstrate that the absence of H2O/CO2 and a static test procedure lead to overrated Oxygen Storage capacities. The method proposed here provides a simple, but not oversimplified method to determine the Oxygen Storage capacity under conditions closer to real applications by imitating the transient working mode of a gasoline engine and paying more attention to the exhaust gas composition.
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SI-Engine Control With Microwave-Assisted Direct Observation of Oxygen Storage Level in Three-Way Catalysts
IEEE Transactions on Control Systems Technology, 2014Co-Authors: Sebastian Schödel, Martin Votsmeier, Ralf Moos, Gerhard FischerauerAbstract:To realize existing emission standards with a reduced amount of noble metals, advanced control strategies for spark ignition (SI) engines are of absolute priority. Such control strategies require precise and accurate information about the actual Oxygen Storage level of the three-way catalyst needed to reduce emissions. This precision is out of reach for state-of-the-art Oxygen Storage models on available on-board hardware. A novel approach toward the solution of this problem is the direct determination of the Oxygen Storage level. This contribution shows how this can be achieved with a model-based microwave measurement system. The method is validated by numerical experiments. It is demonstrated how this approach can be implemented into a new SI engine control algorithm.
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is Oxygen Storage in three way catalysts an equilibrium controlled process
Applied Catalysis B-environmental, 2009Co-Authors: Roman Moller, Martin Votsmeier, Christopher H Onder, Lino Guzzella, Jurgen GieshoffAbstract:Abstract Existing reaction mechanisms for three-way catalysts ignore the oxidation of Ce2O3 by H2O or CO2 and therefore treat Oxygen Storage on ceria as a kinetically controlled non-equilibrium process. Such mechanisms do not correctly reproduce a number of practically important phenomena. Based on transient concentration step experiments, this paper demonstrates that the oxidation of reduced ceria by H2O or CO2 plays an important role for the understanding of the Oxygen Storage dynamics. The results of the step experiments are well reproduced by a simple three-reaction kinetic model that takes into account the equilibrium character of Oxygen Storage. There are a number of effects that cannot be understood based on the conventional non-equilibrium mechanisms: • The Oxygen Storage capacity is lowered by the presence of H2O and CO2. • The Oxygen Storage capacity depends on the amplitude of the lambda-oscillations. • Following a rich-lean step the catalyst emits CO/H2 when there is no CO/H2 in the inlet. • Delayed CO/H2 emissions in the so-called fuel cut-off scenario. • The capability of the Oxygen Storage to dump lambda-oscillations, even if the average lambda is slightly rich. All these effects are explained and quantitatively predicted by the equilibrium based Oxygen Storage model.
Kae Yamamura - One of the best experts on this subject based on the ideXlab platform.
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Effect of ordered arrangement of Ce and Zr ions on Oxygen Storage capacity of ceria-zirconia solid solution
Journal of the Ceramic Society of Japan, 2020Co-Authors: Akihiko Suda, Kae Yamamura, Toshitaka Tanabe, Yoshio Ukyo, Hideo Sobukawa, Tsuyoshi Sasaki, Yasutaka Nagai, Masahiro SugiuraAbstract:The CeO 2 -ZrO 2 solid solution is the most important Oxygen Storage/release material for use in automobile catalysts. In particular, the ceria-zirconia solid solution with a pyrochlore structure exhibits the highest Oxygen Storage capacity (OSC). In this study, CeO 2 -ZrO 2 solid solutions containing Y 2 O 3 were synthesized and their OSCs were measured to clarify the influence of an ordered arrangement of Ce and Zr ions on the OSC. As a result of this study, it is concluded that an ordered arrangement of Ce and Zr ions markedly improves the OSC of CeO 2 -ZrO 2 solid solutions.
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monodisperse ceo2 nanoparticles and their Oxygen Storage and release properties
Journal of Physical Chemistry C, 2011Co-Authors: Haruo Imagawa, Akihiko Suda, Kae YamamuraAbstract:Monodisperse polyhedral nanoparticles (NPs) and nanorods (NRs) of cerium dioxide, CeO2, were synthesized by thermal decomposition of ammonium cerium(IV) nitrate, (NH4)2Ce(NO3)6, at 180 °C in an organic solution of oleylamine (OAm) and/or oleic acid (OA). The 4 nm CeO2 NPs were synthesized in diphenyl ether solution of OAm and OA with the molar ratio of Ce/OAm/OA = 1:3:3, while the 6 nm CeO2 NPs were made in 1-octadecene solution of OAm with Ce/OAm = 1:6. The NRs were formed in 1-octadecene with Ce/OAm/OA = 1:3:1.5. The CeO2 NPs were assembled on γ-Al2O3 via polyvinylpyrrolidone and were annealed at 500 °C under air to remove organic coating. They were well-dispersed on Al2O3 and showed the increased Oxygen Storage capacity compared to the physical mixture of aggregated CeO2 and γ-Al2O3 powder. The reported CeO2 NPs are promising for Oxygen Storage and release applications.
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Extra-low-temperature Oxygen Storage capacity of CeO2 nanocrystals with cubic facets.
Nano Letters, 2011Co-Authors: Jing Zhang, Hitoshi Kumagai, Kae Yamamura, Satoshi Ohara, Akira Morikawa, Hirofumi Shinjoh, Kenji Kaneko, Tadafumi Adschiri, Seiichi Takami, Akihiko SudaAbstract:Herein we demonstrate the extra-low-temperature Oxygen Storage capacity (OSC) of cerium oxide nanocrystals with cubic (100) facets. A considerable OSC occurs at 150 °C without active species loading. This temperature is 250 °C lower than that of irregularly shaped cerium oxide. This result indicates that cubic (100) facets of cerium oxide have the characteristics to be a superior low-temperature catalyst.
