Low Emission Three-way Catalyst and OSC Material Development for OBD Diagnostics

Maunula, Teuvo; Vakkilainen, A.; Lievonen, Ari; Torkkell, Keijo; Niskanen, K.; Härkönen, Matti

doi:10.4271/1999-01-3625

Cited by 11 publications

(5 citation statements)

References 6 publications

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“…Pretreatment for the SSA measurement consisted of holding the sample in vacuum at 350 8C for 16 h. For the dispersion measurement the pretreatment was done with hydrogen at 300 8C for 30 min after which the sample was held in vacuum at 350 8C for 30 min. Total oxygen storage capacity (OSC) was measured with the laboratory equipment using a quartz reactor and a ceramic furnace [11]. The storage capacity (ml), oxygen in washcoat (g) was calculated/measured from the difference between totally CO-adsorbed and O 2 -adsorbed catalyst surface.…”

Section: Characterization Methodsmentioning

confidence: 99%

“…Engine ageing for the prototype samples was made with a Chevrolet V-8 5.0 dm 3 engine using rapid ageing hot (RAH) test schedule [11][12][13]. The ageing procedure consists of both rich, stoichiometric and lean air/fuel ratio modes which is repeated once in a minute.…”

Section: Ageing and Testingmentioning

confidence: 99%

“…The ageing procedure consists of both rich, stoichiometric and lean air/fuel ratio modes which is repeated once in a minute. The ageing time has been 40 h. Prototype samples were tested with a Fiat Seicento 1.1 dm 3 engine using the MVEG-B test (motor vehicle emission group) [11], European stage four drive cycle, which consists of four similar cycle simulating the driving in city area and one cycle simulating the driving in motor way, the test is also called as CVS-test (constant volume sampling). Ageing simulations in laboratory were made in an IR-furnace which enables rapid temperature changes.…”

Section: Ageing and Testingmentioning

confidence: 99%

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Laboratory scale simulation of three-way catalyst engine ageing

Kallinen¹,

Suopanki²,

Härkönen³

2005

Catalysis Today

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Section: Characterization Methodsmentioning

confidence: 99%

Section: Ageing and Testingmentioning

confidence: 99%

Section: Ageing and Testingmentioning

confidence: 99%

See 1 more Smart Citation

Laboratory scale simulation of three-way catalyst engine ageing

Kallinen¹,

Suopanki²,

Härkönen³

2005

Catalysis Today

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“…The performances of automotive pollution control catalysts have been shown to somehow correlates with the OSC of these solids. In fact, the OSC measurement has been considered as a potential indication of the catalyst state -active or inactive -for on-board diagnostic (OBD) applications [10][11][12][13][14]. However, up to now, OSC measurements have been carried out under ideal conditions, in a continuous mode [1,7].…”

Section: Introductionmentioning

confidence: 99%

Oxygen storage capacity measurements of three-way catalysts under transient conditions

Descorme¹,

Taha²,

Mouaddib-Moral³

et al. 2002

Applied Catalysis A: General

103

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Oxygen storage capacity (OSC) measurements at 450 • C were carried out on 10 different alumina and ceria-alumina supported Pd, Pt, Rh, PdRh and PtRh catalysts. Experiments were performed under both transient (0.5 and 1 Hz) and stationary reaction conditions using a mass spectrometer for the gas phase analysis every 100 ms. OSC was shown to be strongly dependent on the metal nature -oxidized or reduced. Rh appeared to be the best OSC promoter. Furthermore, ceria addition to the alumina support strongly enhances the OSC. In fact looking at the OSC values, a factor of 3 was evidenced between Pt/Al 2 O 3 and Rh/Al 2 O 3 and an additional factor of about 12 between Rh/Al 2 O 3 and Rh/CeO 2 -Al 2 O 3 . The metal oxides relative stability as well as the metal electronic configuration were shown to be strongly influent on the overall reactivity of the catalyst. Additional kinetic studies showed that the oxide reduction rate under CO is slower than the oxide oxidation rate under O 2 . Finally a general scheme for the oxygen storage process is proposed and discussed.

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“…The total OSC was measured with a laboratory equipment using a quartz reactor and a ceramic furnace [3]. The storage capacity of oxygen (O 2 ml) on the washcoat (g) was calculated from the difference between a totally CO-adsorbed and O 2 -adsorbed catalyst surface [2].…”

Section: Catalyst Characterisationmentioning

confidence: 99%

The effect of La2O3 on dynamic OSC over the Pd/OSC/Al2O3-based catalysts

2007

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In this study, fresh and aged Pd/(OSC-Al 2 O 3 ) and Pd/(Al 2 O 3 -OSC-La 2 O 3 ) metallic monoliths (OSC material Ce 0.75 Zr 0.25 O 2 ) were used to find out the effect of La 2 O 3 on the catalyst behaviour in dynamic oxygen storage capacity (OSC) measurements. In addition, the interaction of CO, NO and O 2 reaction compounds over the studied catalysts was investigated in order to understand the effect of La 2 O 3 in the oxidation and reduction reactions in lean automotive exhaust gas conditions. A FT-IR gas analyser was used to analyse the product gas composition. The presence of La 2 O 3 on fresh and aged catalysts had negative effect on both the dynamic OSC and the activity of the catalyst. The reason for this is the different washcoat compositions between the studied catalysts which could explain the differences in BET surface areas.

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Low Emission Three-way Catalyst and OSC Material Development for OBD Diagnostics

Cited by 11 publications

References 6 publications

Laboratory scale simulation of three-way catalyst engine ageing

Laboratory scale simulation of three-way catalyst engine ageing

Oxygen storage capacity measurements of three-way catalysts under transient conditions

The effect of La2O3 on dynamic OSC over the Pd/OSC/Al2O3-based catalysts

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