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The reduction of particulate emissions from diesel engines is of major interest, considering the strict emission standards posed by the legislation worldwide. Although the technology of particulate filters has been under development for more than 20 years, considerable technological challenges remain regarding effectiveness and durability. The emergence of the continuous regenerating trap (CRT) in conjunction with the availability of low-sulfur diesel fuel represents a promising solution, especially for heavy-duty engines. In the present paper, a modeling approach for the combined catalyst and diesel particulate filter system is presented. The model is used to understand the main behavior trends of the oxidation catalyst and the NO 2 regenerated trap individually and as a system. Illustrative model applications are also presented for the case of a modern heavy-duty engine and operating conditions corresponding to the European testing procedures. Although the model is based on global reaction schemes, it is useful in explaining the parameters affecting the CRT system behavior in the real world. Such engineering models are expected to support the selection and design of CRT systems, minimizing the testing effort.

The diesel particulate filter (DPF) technology with the use of fuel additives as regeneration aids is a promising technology for modern and future low-emissions diesel engines. The development of efficient and reliable DPF systems requires understanding of the regeneration process. Although the role of mathematical models in this respect has been widely recognized, few attempts to model the fuel-additive-assisted regeneration have been presented. In this work, a previously developed simplified authors' model is extended, to allow deeper investigation of the process. The 1D mathematical model of the catalytic regeneration in the channel of the particulate filter is based on a dynamic oxygen storage/release mechanism of additive action, coupled to the transport phenomena occurring in the filter. A previously published set of fullscale measurements is employed to validate the model in a wide range of possible regeneration modes. The advantages of the present 1D model over the previous 0D model are illustrated. It is concluded that, at the present stage, the model can sufficiently describe and explain the main features of the regeneration process. The minor deviations of the model results from reality are attributed to the uncertainties of the reaction kinetics and to nonuniformities regarding flow distribution and soot deposition. The possible explanations are discussed, and directions for future work are suggested.

Pressure drop modelling is a subject of special Due to the fuel penalty resulting from the increased backpressure of the loaded filter, it is necessary interest for the design and control of diesel particulate for the filter to be regenerated. This regeneration filters. Based on previous experience, an improved pressure involves oxidation of the accumulated particulate, drop model is presented. Special emphasis is given on the which may be periodical or continuous, during soot permeability properties and its dependence on temregular engine operation. The initiation and control perature and pressure. With the assumption of uniform of the regeneration process is the main issue in diesel wall flow distribution throughout the channel length, it filter technology, as regeneration should be as safe is possible to derive an analytic expression for pressure as possible to avoid excessive thermal stresses and drop calculation. The main difference with previously profailure of the filter material. Regeneration systems posed analytic expressions lies in the inclusion of gas are based on the use of catalysts (catalytic coatings density dependence on local pressure, which necessitates or fuel-borne catalysts) to lower the reaction teman iterative calculation procedure. The importance of this perature and/or engine measures (e.g. post-injection) improvement is illustrated parametrically. The new model or electrical heating to increase the exhaust gas is validated against experimental data on an engine bench, temperature. using a double filter configuration to ensure constant filter Understanding the flow phenomena contributing soot loading throughout the test.to the pressure drop in particulate filters is of great importance for the emissions engineer. On the one Key words: diesel engine, after-treatment technology, hand, filter design should target the minimization of exhaust emissions, mathematical modelling, pressure drop pressure drop in real-world conditions by careful selection of filter geometry (volume, cell density, wall thickness, porosity). On the other hand, the

Stricter emission control legislation for diesel use has been increasing interest in highly

Mathematical modeling of three-way catalytic converter (3WCC) operation is increasingly employed in automotive catalyst and converter systems optimization. Oxygen storage is known to strongly affect catalytic converter operation under real world transient operating conditions. This paper presents a modeling approach embodying a comprehensive oxygen storage and release submodel into an existing 3WCC quasi-steady model. The dynamic model developed according to this approach is validated against previously published experimental data. The model sensitivity to each of the oxygen storage parameters is examined. The results of this investigation encourage further application of mathematical modeling in areas such as air-to-fuel (A/F) ratio control strategy optimization, which lie beyond the scope of traditional kinetic 3WCC models.

The diesel particulate filters (DPFs) technology has impressively advanced especially during the last years, driven by the interest in the reduction of automobile particulate emissions. This paper is concerned with the effect of NO 2 as an active oxidation agent in the regeneration process of the soot accumulated in the particulate filter. Experiments at realistic conditions using a diesel engine equipped with a standard oxidation catalyst and a particulate filter are carried out at a wide range of operating conditions. These results are used to validate an already available mathematical model of the NO 2 -assisted regeneration phenomena in the particulate filter. The combined use of experimental and modeling results provides interesting conclusions regarding the significance and the chemistry of the reaction of soot with NO 2 . The advantages and drawbacks of such an approach compared to standard laboratory synthetic gas studies are discussed. The agreement between experimental and simulation results in terms of engineering interest (rate of soot accumulation or depletion) is quite satisfactory and indicates that such a type of model could be a promising design tool.