Peter Flörchinger

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.

DPF Regeneration-Concept to Avoid Uncontrolled Regeneration During Idle

Significant particulate emission reductions of diesel engines can be achieved using diesel particulate filters (DPFs). Ceramic wall flow filters with a PM efficiency of >90% have proven to be effective components in emission control. The challenge for the application lies with the development and adaptation of a reliable regeneration strategy. The main focus is emission efficiency over the legally required durability periods, as well as over the useful vehicle life. It will be shown, that new DPF systems are characterized by a high degree of integration with the engine management system, to allow for initiation of the regeneration and its control for optimum DPF protection. Using selected cases, the optimum combination and tuning will be demonstrated for successful regenerations, taking into account DPF properties. For example, high DPF durability, good DPF regenerability, and low system pressure drop are balanced with engine based parameters like air mass flow, exhaust gas temperature, and exhaust oxygen content. Advanced system control techniques, such as tuning and optimization will be presented and discussed. New possibilities of the application of new robust and cost effective DPF systems will be shown.

Prediction and validation of pressure drop for Catalyzed Diesel particulate filters

To meet the future emission targets for Diesel engines, one trend is the use of Catalyzed Diesel Particulate Filters (CDPF). Catalyzing the filter, however, alters filter behavior. In particular, alteration in filter permeability imparts a significant change in the filters performance. To understand the impact of the catalyst coating on a DPF, engine tests have been conducted to measure the pressure drop across DPFs with different catalyst coatings, cell densities, and soot loadings. The tests were performed over a range of engine speeds and loads, with a corresponding range in exhaust flow rates and temperatures. A pressure drop model based on previous work for uncatalyzed filters has been modified and validated for CDPFs. To achieve optimum design for DPFs, a parametric study comparing the influence of catalyst, cell density, wall thickness, filter length and diameter was done.

Druckverlustmodell für keramische Dieselpartikelfilter

Fur den Einsatz von Partikelfiltern bei der Dieselmotor-Abgasnachbehandlung ist die Kenntnis des Druckverlustverhaltens wahrend der Rusbeladung von grosem Interesse. Zum besseren Verstandnis der Stromungsverhaltnisse in einem keramischen Wabenfilter muss zunachst jedoch das Druckverlustverhalten eines unbeladenen Filters untersucht werden. Deshalb wurde bei Corning ein Programm entwickelt, mit dem sich der Druckverlust eines unbeladenen Diesel-Partikelfilters in guter Genauigkeit beschreiben lasst. Im Folgenden wird dieses Modell vorgestellt und gezeigt, wie es zur Beschreibung des Druckverlustes von leicht beladenen Filtern erweitert werden kann. In einer Parameterstudie wurde der Einfluss von Filtergeometrie und — lange auf das Druckverlustverhalten bei verschiedenen Durchflussraten fur un- und leicht beladene Filter untersucht.

Comparative analysis of different heavy duty diesel oxidation catalysts configurations

Diesel Oxidation Catalyst in conjunction with large frontal area substrates is a key element in HDV Diesel emission control systems. This paper describes and reviews tests on a set of various Diesel Oxidation Catalyst configurations (for example cell densities), all with the same catalyst coating. The Diesel Oxidation Catalyst specimens were subjected to the European Stationary Cycle (ESC), the European Transient Cycle (ETC), and the US heavy duty Federal Test Procedure (US FTP). The focus was to study relative emissions, pressure drop, and light-off perfor ance. All tests were conducted using the same Detroit Diesel Series 60 engine operating on ultra low sulfur diesel fuel. In addition to this, the exhaust was regulated so that the backpressure on the engine, upstream of the catalyst was also the same for all catalysts. The engine, the exhaust system, and the Diesel Oxidation Catalyst were properly instrumented to monitor incoming exhaust composition and final emissions, temperatures, mass flows, and pressure drop. Prior to the catalyst screening each catalyst was degreened by conducting two ESC and two US heavy-duty transient cycles in an alternate order back-to-back starting with the ESC to guarantee a proper seal between substrate, housing, and mat material. The test procedures will be explained in detail and the analysis of the data and conclusions for performance differences discussed.

Systeme zur Abgasnachbehandlung in Nutzfahrzeugen. Einsatz und Optimierung

Fur die Abgasnachbehandlung in Nutzfahrzeugen werden zurzeit verschiedene Technologien entwickelt oder stehen kurz vor ihrer Einfuhrung. Bei der Entwicklung mussen Randbedingungen wie Wirtschaftlichkeit und Transportleistung berucksichtigt werden. Dieser Beitrag der Corning GmbH stellt die heutigen Technologien und Auslegungskriterien fur die Abgasnachbehandlung im Nutzfahrzeug dar und zeigt Moglichkeiten fur eine zukunftige Optimierung dieser Systeme.

A concept for advanced DPF regeneration

Wall-flow, high-efficiency diesel particulate filters (DPF) have proven to significantly reduce the PM emissions of diesel engines and will be seen in rapidly increasing numbers of European diesel passenger cars. The challenges ahead for these “active” DPF systems are their enhanced cost-effectiveness while not compromising on vehicle/engine performance and emission safety.

Application and optimisation of emission control systems in commercial vehicles

At the present time, various technologies are being developed for emission control systems in commercial vehicles. Some of these will be introduced in the near future. In their development, basic constraints such as economic viability and performance must be taken into account. This article by Corning presents today’s technologies and design criteria for exhaust gas aftertreatment in commercial vehicles, and aims to provide an overview of the options available for the future optimisation of such systems.

High-performance ceramic substrates for catalytic converters

Higher performance requirements for exhaust gas aftertreatment systems for passenger cars have led to the development of high cell density substrates with walls thinner than a human hair. Whereas the majority of these substrates have a square cell geometry, the potential for further emission improvements has been predicted for hexagonal cell structures. In order to verify these predictions, Corning has developed a ceramic substrate that combines the features of high cell density, ultra-thin cell walls and hexagonal cell geometry. The emission tests were conducted by Volkswagen, who compared the new substrate concept with square cell ceramic substrates.