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Catalyzed diesel particulate filter systems have now been successfully introduced and implemented in Europe. In the meantime, automotive manufacturers are working on the second generation of catalytic filters with the aim of reducing the overall system costs. In particular savings in precious metal costs are focussed by the use of highly-active catalysts which are stable at high temperatures. A possible approach here is the implementation of oxidation catalysts and catalytically coated filters based on platinum and palladium. In this context, the functio-nality of platinum/palladium-based, catalyzed filters was investigated by numerous measurements on a synthetic gas and an engine bench as well as by vehicle tests on a roller dynamometer. The HC/CO oxidation activity, the poisoning resistance towards sulfur and the desulfurization capability, the exothermic behaviour due to the conversion of subsequently injected hydrocarbons and the NO2 formation potential were examined in detail.

The reduction of diesel emissions will remain a major challenge in the near future. Based on the expected emissions legislation for Europe and NAFTA, respectively, two main routes to approach this challenge are possible. Especially for the NAFTA market the use of a NOx emission control system is highly probable due to the established low limit for NOx emissions. From today's point of view only two systems - the NOx storage catalyst and the SCR catalyst system - have the potential to reach these limits. In Europe the expected Euro5 NOx limit can most likely be reached by engine measures only. Nevertheless both markets have the common understanding that besides the further improvement by internal engine measures the diesel oxidation catalyst (DOC) as well as the catalysed diesel particulate (DPF) filter will play an essential role in diesel emissions reduction.

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.

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 PM-Filter 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.

Several diesel passenger car manufacturers in the European Union recently announced the future use of catalyzed diesel particulate filter systems on their vehicles. The major technical challenge is the periodical regeneration of the filters loaded with the retained diesel particulates. In order to promote filter regeneration, catalytic activation of the accumulated soot is advantageous. Therefore, the first serial application of diesel particulate filter systems uses catalytically active fuel additives. These systems were introduced about four years ago. Since that time, other systems, using a dedicated catalytically activated diesel particulate filter combined with an upstream diesel oxidation catalyst, have been introduced as well. This allows filter regeneration without extra fuel additives. In the past, adding catalytic coating to a filter substrate has often resulted in increasing the pressure drop over the filter to an unacceptable level.

This paper describes a study of ternary V2O5/WO3/TiO2 SCR catalysts coated on standard Celcor® and new highly porous cordierite substrates. At temperatures below 275°C, where NOx conversion is kinetically limited, high catalyst loadings are required to achieve high conversion efficiencies. In principle there are two ways to achieve high catalyst loadings: 1. On standard Celcor® substrates the washcoat thickness can be increased. 2. With new highly porous substrates a high amount of washcoat can be deposited in the walls. Various catalyst loadings varying from 120g/l to 540 g/l were washcoated on both standard Celcor® and new high porosity cordierite substrates with standard coating techniques. Simulated laboratory testing of these samples showed that high catalyst loadings improved both low temperature conversion efficiency and high temperature ammonia storage capacity and consequently increased the overall conversion efficiency.

The regeneration of a loaded particulate filter is one of the biggest challenges in the development of filter systems. The reason is under certain conditions the exhaust gas temperature does not reach the required minimum regeneration temperature for a longer period of time. This paper describes results achieved with a catalytically coated filter alone and in combination with engine parameters, which are used to increase the exhaust gas temperature. The activity of the catalytically coated filter was evaluated by using the well-known balance temperature test. The soot-burning rate was determined at different exhaust gas temperatures. The investigated engine control parameters included intake air throttling and a control of lambda. A special low-temperature transient test was designed to evaluate the regeneration efficiency of the catalytically coated filter and the described engine control parameters under more realistic conditions.

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 NO2/NO ratio. The concentrations of different components (NO, NO2, N2O, NH3, H2O and HNO3) 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.

The LEV II and EURO V legislation in 2007/2008 require a high conversion level for nitrogen oxides to meet the emission levels for diesel SUVs and trucks. Therefore, U.S. and European truck manufacturers are considering the introduction of urea SCR systems no later than model year 2005. The current SCR catalysts are based mainly on systems derived from stationary power plant applications. Therefore, improved washcoat based monolith catalysts were developed using standard types of formulations. These catalysts achieved high conversion levels similar to extruded systems in passenger car and truck test cycles. However, to meet further tightening of standards, a new class of catalysts was developed. These advanced type of catalytic coatings proved to be equivalent or even better than standard washcoat formulations. Results will be shown from ESC, MVEG and US-FTP 75 tests to illustrate the progress in catalyst design for urea SCR.

This paper describes the function and application of the preoxidation, hydrolysis and SCR catalysts individually and as a combined system for urea SCR both in model gas and engine bench tests. Using the basic system and a non-optimized urea injection strategy 45% NOx conversion was achieved in the ESC engine test. Adding a preoxidation catalyst significantly improved the NOx conversion in the low temperature region of the engine mapping. NOx conversions over 75% can be achieved in the ESC test using this improved system. With a 50% reduced SCR catalyst volume still a NOx conversion of over 65% could be achieved. Tests after 200 hours engine aging show that the activity of the system is stable.