Paul Spurk

Modeling of SCR DeNOx Catalyst - Looking at the Impact of Substrate Attributes

The present work intends to examine the selective NOx reduction efficiency of a current commercial Titanium-Vanadium washcoated catalyst and to develop a transient numerical model capable of describing the SCR process while using a wide range of inlet conditions such as space velocity, oxygen concentrations, water concentration and NO 2 /NO ratio. The concentrations of different components (NO, NO 2 , N 2 O, NH 3 , H 2 O and HNO 3 ) were analyzed continuously by a FT-IR spectrometer. A temperature range from 150°C up to 650°C was examined and tests were carried out using a model exhaust gas comparable to the real diesel exhaust gas composition. There is a very good correlation between experimental and calculated results with the given chemical kinetics.

Turbulent Flow Metal Substrates: A Way to Address Cold Start CO Emissions and to Optimize Catalyst Loading

Modern Diesel Engines equipped with Common-Rail Direct Injection and EGR are characterized by an increasingly high combustion efficiency. Consequently the exhaust gas temperature, especially during a cold start, is significantly reduced compared to typical values measured in previous engine generations. This leads to a potential problem with CO emission limit compliance. The present paper deals with an experimental investigation of turbulent-flow metal substrates, carried out on a vehicle roller bench using a production 1.3 Liter diesel engine equipped passenger car. The tested metal supported catalysts proved to yield extremely high conversion rates both during cold start and in warm operation phase. The improved mass transfer efficiency of the advanced metal substrates is related on one hand to the optimized coating technology and, on the other hand, to the enhanced flow performance in the single converter channels which is caused by structured metal foils. Additionally different cost saving scenarios have been analyzed by means of both catalyst volume reduction and decreased PGM loading.

Impacts of Diesel-HEVs on exhaust gas aftertreatment systems for future emission legislations

The ongoing electrification of Diesel powertrains along with the introduction of new test procedures by the European Union creates new challenges for the development of the next generation of exhaust gas aftertreatment systems. The electrification leads to changed operating conditions of the combustion engine resulting in temporarily higher engine-out emissions and simultaneously lowered exhaust gas temperatures. Additionally, the exhaust gas aftertreatment system will have to deal with higher exhaust gas mass flows, due to the upcoming new test procedures and real driving emission tests. Therefore the boundary conditions at Diesel-HEVs require a close coupled positioning especially of the DeNOx function to ensure high conversion rates over wide range of operating conditions and engine out emissions. The DeNOx potential of different exhaust gas aftertreatment systems for the use in Diesel-HEVs will be discussed in this paper. On the one hand, the applied testing methodology includes tests at the Engine-in-the- Loop (EiL) testbed. With the EiL testbed the simulation of different powertrain configurations is used to show the influence of these configurations on the thermal conditions in the exhaust gas aftertreatment system and to evaluate the emissions and their conversion. On the other hand, on road and vehicle dynamometer measurements with state of the art Diesel-HEVs are used to determine the NOx emissions and thermal conditions during real driving scenarios.

Innovative metal supported catalysts for EU V Diesel Engines

Future stringent emission levels for NOx and PM will lead to the introduction of innovative combustion processes for diesel engines, such as premixed combustion, with the results to enhance the engine out emission of HC and CO. Therefore very efficient oxidation catalyst will be needed to face this possible issue. This paper deals with the optimization of a EU IV exhaust system by means of innovative metal supported catalyst, as for example the Pre Turbo Catalyst and the Hybrid Catalyst in combination with dedicated catalyst coatings. Moreover a base study over the use of PMFilter Catalyst has been made, to show the efficiency of such a device with EU IV engine calibration. The second part of the paper deals with the turbulent like structured foils substrates to have an even more efficient diesel oxidation catalyst with very high volumetric efficiency.