Exhaust Gas Aftertreatment in Mobile Systems: Status, Challenges, and Perspectives

Deutschmann, Olaf; Grunwaldt, Jan‐Dierk

doi:10.1002/cite.201200188

Cited by 90 publications

(49 citation statements)

References 153 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the future, efficient material screening will play an essential role in the achievement of step change improvements in exhaust gas aftertreatment technologies. This is enabled by knowledge-based robot-controlled preparation and dynamic models coupled with information from real operation [2].…”

Section: Introductionmentioning

confidence: 99%

High-Throughput Screening as a Supplemental Tool for the Development of Advanced Emission Control Catalysts: Methodological Approaches and Data Processing

Sundermann¹,

Gerlach²

2016

Catalysts

View full text Add to dashboard Cite

Abstract:A high-throughput (HT) screening platform developed at hte with the application focus on automotive catalysis is described. hte HT units are configured for performing steady-state testing, as well as dynamic tests with fast feed switches, such as lean/rich excursions for the evaluation of NO x storage capacity and efficiency of lean NO x traps (LNT), ammonia storage capacity for selective catalytic reduction (SCR), evaluation of oxygen storage capacity (OSC), as well as lambda sweep tests for screening of three-way catalysts (TWC). Even though catalysts are screened on a rather small scale (~100 mg powder), experience showed that dosing rather complex gas mixtures in concentrations close to that found in real exhaust for the given application is mandatory to generate relevant data. The objective of this work is to give additional insight into HT technology. In the industrial research laboratory, HT screening has matured to become a reliable approach for rapid screening of both reaction parameter spaces, as well as material properties relevant for exhaust gas catalyst development. Due to the speed of optimized screening involving 48 parallel reactors, automated handling of primary data is an imported requirement. Software for data reduction, like estimation of light-off temperature, needs to be robust and handle results for diverse sample libraries in an unattended fashion. In combination with the statistical design of experiment and multivariate data analysis, HT testing has become a valuable enhancement to automotive catalyst development.

show abstract

Section: Introductionmentioning

confidence: 99%

High-Throughput Screening as a Supplemental Tool for the Development of Advanced Emission Control Catalysts: Methodological Approaches and Data Processing

Sundermann¹,

Gerlach²

2016

Catalysts

View full text Add to dashboard Cite

show abstract

“…They consist of ceramic honeycomb monoliths, mostly of cordierite, with small channels that are coated with a so-called washcoat. A typical washcoat consists of carrier oxides of stabilized alumina, highly dispersed precious metals (Pt, Rh, and Pd) and an oxygen buffer of ceria zirconia solid solutions [3]. The washcoat provides specific surfaces in the range of 100 m 2 /g.…”

Section: Introductionmentioning

confidence: 99%

In operando Detection of Three-Way Catalyst Aging by a Microwave-Based Method: Initial Studies

2015

View full text Add to dashboard Cite

Initial studies on aging detection of three way catalysts with a microwave cavity perturbation method were conducted. Two physico-chemical effects correlate with the aging state. At high temperatures, the resonance frequencies for oxidized catalysts (λ = 1.02) are not influenced by aging, but are significantly affected by aging in the reduced case (λ = 0.98). The catalyst aging state can therefore potentially be inferred from the resonance frequency differences between reduced and oxidized states or from the resonance frequency amplitudes during lambda oscillations. Secondly, adsorbed water at low temperatures strongly affects the resonance frequencies. Light-off experiment studies showed that the resonance frequency depends on the aging state at temperatures below the oxygen storage light-off. These differences were attributed to different water sorption capabilities of differently aged samples due to a surface area decrease with proceeding aging. In addition to the aging state, the water content in the feed gas and the temperature affect the amount of adsorbed water, leading to different integral electrical material properties of the catalyst and changing the resonance properties of the catalyst-filled canning. The classical aging-related properties of the catalyst (oxygen storage capacity, oxygen storage light-off, surface area), agreed very well with data obtained by the microwave-based method. OPEN ACCESSAppl. Sci. 2015, 5 175

show abstract

“…The sensors were operated constantly at 300 • C as absolute sensor temperature. Readjusting for different flow rates is done by controlling the four-wire resistance in the heater structure to a constant value (Bischof et al, 1999;Wiegärtner et al, 2015). For data visualization, the temperature gradient ( T , concerning the sensor's front side) was calculated from the voltage signal and plotted over the gas flow rate.…”

Section: Measurements In Airmentioning

confidence: 99%

“…Automotive exhausts are particularly challenging for gas sensors (Deutschmann and Grunwaldt, 2013;Twigg, 2003). On the one hand, fast and detailed information about the actual (mostly low) concentration of a certain gas component is necessary for efficient after-treatment technologies.…”

Section: Introductionmentioning

confidence: 99%

A pathway to eliminate the gas flow dependency of a hydrocarbon sensor for automotive exhaust applications

Hagen

Harsch

Moos

2018

J. Sens. Sens. Syst.

View full text Add to dashboard Cite

Abstract. Gas sensors will play an essential role in future combustion-based mobility to effectively reduce emissions and monitor the exhausts reliably. In particular, an application in automotive exhausts is challenging due to the high gas temperatures that come along with highly dynamic flow rates. Recently, a thermoelectric hydrocarbon sensor was developed by using materials which are well known in the exhausts and therefore provide the required stability. As a sensing mechanism, the temperature difference that is generated between a catalytically activated area during the exothermic oxidation of said hydrocarbons and an inert area of the sensor is measured by a special screen-printed thermopile structure. As a matter of principle, this thermovoltage significantly depends on the mass flow rate of the exhausts under certain conditions. The present contribution helps to understand this cross effect and proposes a possible setup for its avoidance. By installing the sensor in the correct position of a bypass solution, the gas flow around the sensor is almost free of turbulence. Now, the signal depends only on the hydrocarbon concentration and not on the gas flow. Such a setup may open up new possibilities of applying novel sensors in automotive exhausts for on-board-measurement (OBM) purposes.

show abstract

Exhaust Gas Aftertreatment in Mobile Systems: Status, Challenges, and Perspectives

Cited by 90 publications

References 153 publications

High-Throughput Screening as a Supplemental Tool for the Development of Advanced Emission Control Catalysts: Methodological Approaches and Data Processing

High-Throughput Screening as a Supplemental Tool for the Development of Advanced Emission Control Catalysts: Methodological Approaches and Data Processing

In operando Detection of Three-Way Catalyst Aging by a Microwave-Based Method: Initial Studies

A pathway to eliminate the gas flow dependency of a hydrocarbon sensor for automotive exhaust applications

Contact Info

Product

Resources

About