Catalytic automotive exhaust aftertreatment

http://www.mie.uth.gr/labs/ltte/grk/pubs/comb_flame.pdf

Thermogravimetric analysis of soot emitted by a modern diesel engine run on catalyst-doped fuel

Comprehensive kinetic characterization of the oxidation and gasification of model and real diesel soot by nitrogen oxides and oxygen under engine exhaust conditions: Measurement, Langmuir–Hinshelwood, and Arrhenius parameters

Oxidation of carbon by NOx, with particular reference to NO2 and N2O

One-dimensional automotive catalyst modeling

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 NO2 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 NO2-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 NO2. 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...

Diesel Soot Oxidation with NO2: Engine Experiments and Simulations

Pressure drop modelling is a subject of special interest for the design and control of diesel particulate filters. Based on previous experience, an improved pressure drop model is presented. Special emphasis is given on the soot permeability properties and its dependence on temperature and pressure. With the assumption of uniform wall flow distribution throughout the channel length, it is possible to derive an analytic expression for pressure drop calculation. The main difference with previously proposed analytic expressions lies in the inclusion of gas density dependence on local pressure, which necessitates an iterative calculation procedure. The importance of this improvement is illustrated parametrically. The new model is validated against experimental data on an engine bench, using a double filter configuration to ensure constant filter soot loading throughout the test.

Diesel particulate filter pressure drop Part 1: modelling and experimental validation

The advent of stricter U.S. and European exhaust emissions regulations has increased the need for reliable 3-way catalytic converter models supporting the design of demanding exhaust systems for low-emitting vehicles. Although a number of tunable models have been presented in the literature, their efficient performance in actual 3-way applicaions requires further development and validation. The major difficulties posed in such modeling efforts arise from the complexities in the reaction schemes and the respective rate expressions for the multitude of currently used catalyst formulations. This paper addresses the details of tuning and real world application of a two-dimensional catalytic converter model, which accounts for the HC (hydrocarbons) and CO oxidation, as well as NO reduction reactions. The model features a number of innovations regarding the catalyst transient behaviour modelling and the reaction kinetics scheme. The advanced oxygen storage submodel presented is capable of accounting fo...

Three-way catalytic converter modeling and applications

Computer aided engineering (CAE) methodologies are increasingly being applied to assist the design of spark-ignition (SI) engine exhaust aftertreatment systems in view of the stage III and IV emissions standards. Following this trend, the design of diesel exhaust aftertreatment systems is receiving more attention owing to the capabilities of recently developed mathematical models. The design of diesel exhaust systems must cope with three major aftertreatment categories: diesel oxidation catalysts, diesel particulate filters and de-NOx catalytic converters. An integrated CAE methodology that could assist the design of all these classes of systems is described in this paper. It employs the following computational tools: a computer code for modelling transient exhaust system heat transfer, a computer code for modelling the transient operation of a diesel oxidation or a de-NOx catalytic converter, a database containing chemical kinetics data for a variety of oxidation and de-NOx catalyst formulations ...

Computer aided engineering in diesel exhaust aftertreatment systems design

Initiation of the regeneration of porous ceramic diesel particulate filters at low exhaust gas temperatures and the subsequent control of the soot oxidation rate is necessary in order to allow a wide applicability of filter systems in diesel-powered vehicles. The use of catalysts in this respect, in particular catalytic fuel additives, has been proven to be successful, leading to a minimization of the system's cost and additional fuel consumption. Better understanding and modeling of the catalytic activity at low temperatures necessitates that one takes into account the oxidation not only of dry particulate but also of the volatile hydrocarbons adsorbed on the particulate. In this paper, the oxidation of the hydrocarbons adsorbed on the particulate is modeled, to allow a better understanding of the filter regeneration behavior at very low temperatures (150−300 °C). A simplified reaction scheme and tunable kinetics are employed in the description of adsorbed hydrocarbon oxidation. The mechanism is incorpor...

I. P. Kandylas

Papers

Diesel Soot Oxidation with NO2: Engine Experiments and Simulations

Diesel particulate filter pressure drop Part 1: modelling and experimental validation

Three-way catalytic converter modeling and applications

Computer aided engineering in diesel exhaust aftertreatment systems design

Modeling Catalytic Regeneration of Diesel Particulate Filters, Taking into Account Adsorbed Hydrocarbon Oxidation