A Modular Numerical Simulation Tool Predicting Catalytic Converter Light-Off by Improved Modeling of Thermal Management and Conversion Characteristics

Büchner, S.; Lardies, S. Santos; Degen, Alf; Donnerstag, A.; Held, Wolfgang

doi:10.4271/2001-01-0940

Cited by 22 publications

(7 citation statements)

References 11 publications

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“…The thermal model simulates the heat transfers occurring in the DOC monolith and is used to predict the temperatures of both the solid and the gas. The thermal model is based on the work presented in the studies by Lubesky 19 and Buechner et al 20 and is a quasi-steady-state model, since it is based on the assumption that the characteristic time constant of the flow rate and temperature is much higher than the residence time of the flow. The convective heat transfer rate is calculated from the average gas temperature across the j th element (the DOC can be divided into four or five bricks, depending on the specific case) and the average solid temperature during the i th computational time step (Figure 6).…”

Section: The Doc Modelmentioning

confidence: 99%

Modeling of diesel oxidation catalysts for calibration and control purpose

Mallamo

Longhi

Millo

et al. 2013

International Journal of Engine Research

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An approach to the analysis of the performance of the diesel oxidation catalysts is presented in this article. A modeling methodology is proposed, whose main characteristics are the usage of a limited set of input data for the execution of the simulations, the minimal effort required for the preliminary calibration of the models and the reduced computational time. The developed diesel oxidation catalyst model structure is described, and its predictive capability is shown by means of a comparison with experimental measurements. The model is based on quasi-zero-dimensional and quasisteady-state approaches, which ensure a reasonable compromise between practicality of usage (including faster than real-time computational time) and quality of the results. Thanks to the quick execution and the accuracy of the results, the proposed modeling approach can be used not only for the development of the diesel powertrains but also for the optimization of the related control and calibration strategies. This process is particularly effective when the models for the aftertreatment systems are coupled with models for the prediction of the engine-out quantities and with software tools for the virtual calibration of the main engine and exhaust system control parameters. A specific example of the effectiveness of this kind of analysis is also given in this article, with focus on the assessment of the system robustness.

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Section: The Doc Modelmentioning

confidence: 99%

Modeling of diesel oxidation catalysts for calibration and control purpose

Mallamo

Longhi

Millo

et al. 2013

International Journal of Engine Research

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“…Based on the methodology outlined by Konstantinidis et al [3] and Buchner et al [4], a model was developed to solve non-steady conduction within metal pipe sections.…”

Section: Brief Model Overviewmentioning

confidence: 99%

“…In addition, the energy flows associated with conduction to the head and adjacent pipe section, with radiation and convection to the surroundings on the outer wall, and with convective heat transfer between the gas and inner wall of the section are included and solved via an energy balance including an energy storage term. Published relationships for free and forced convection to the surroundings [3][4][5] were included in the model. The degree of forced convection is dependent on the velocity of the air flowing over the pipe section as well as its wetted area.…”

Section: Brief Model Overviewmentioning

confidence: 99%

An empirical approach to predicting heat transfer within single- and twin-skin automotive exhaust systems

Bannister

Brace

Taylor

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part D:

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This paper describes the further development of an exhaust system model based on the experimental characterisation of heat transfer in a series of different pipe sections. Building on previous work published in this journal by the authors, this study was undertaken to improve the operating range, accuracy and usability of the original model as well as introducing the ability to model twin skin exhaust sections with an air gap. Convective heat transfer relationships for nine stainless steel exhaust bend sections of varying wall thicknesses and radiuses were experimentally characterised over a range of steady state conditions. In each case a correlation between observed Reynolds number (Re) and Nusselt number (Nu) was developed. Based on measured experimental data, a generic model was built using Matlab/Simulink capable of predicting the relationship between Nusselt number and Reynolds number for previously unseen pipe geometries falling within the experimental design range. To further develop the usefulness of the model, fifteen twin skin test sections, intended to represent a range of geometries applicable to production automotive gasoline exhaust systems, were also fabricated and characterised. Within the model, both skins of each pipe section were split into five axial and radial elements with the inner and outer skins linked via the modelling of free convection and radiation between them. The predicted Reynolds-Nusselt relationships for each bend section and twin skin configuration were validated using transient experimental data over a portion of the US06 drive cycle. The final model demonstrated improved accuracy of exhaust gas temperature predictions, compared with previous model iterations, with typical errors of less than ±1% and a mean error over the US06 cycle of +0.2%.

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“…Based on the methodology outlined by Konstantinidis et al [3] and Buchner et al [4] a new model was developed to solve non-steady conduction within flanges and thick-walled sections but, because of the minimal impact on computation time, this approach was applied to all sections within the model regardless of wall thickness.…”

Section: Thick-walled Sections and Flangesmentioning

confidence: 99%

The use of multi-variate models for the prediction of heat transfer in vehicle exhaust systems

Bannister

Brace

Taylor

et al. 2009

Proceedings of the Institution of Mechanical Engineers, Part D:

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This paper describes the development of an exhaust system model based on the characterization of heat transfer in a series of 11 test sections designed to represent a range of configurations seen in production exhaust systems. These sections include variations in the wall thickness, diameter, bend angle, and radius. This work is part of a larger activity aimed at the accurate modelling of heat transfer and subsequent catalyst light-off in production exhaust systems consisting of similar geometries.For each section a range of steady state tests was performed on a dynamic test cell using a port injected gasoline engine. In each case a correlation between the observed Reynolds number Re and the Nusselt number Nu was developed. A model of the system was implemented in MATLAB-Simulink in which each pipe element was split into 25 subelements by dividing the pipe into five, both axially and radially. After each individual section had been characterized, a generic model was built that was capable of determining the relationship between the Nusselt number and the Reynolds number for previously unseen pipe geometries. Complex exhaust systems can be constructed from smaller elements of defined geometry. The modelling approach was validated using experimental data gathered from vehicle testing on a chassis dynamometer.The steady state relationship between Re and Nu allows heat transfer in the test section to be predicted over transient test cycles and demonstrates good agreement with relationships in the literature.

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A Modular Numerical Simulation Tool Predicting Catalytic Converter Light-Off by Improved Modeling of Thermal Management and Conversion Characteristics

Cited by 22 publications

References 11 publications

Modeling of diesel oxidation catalysts for calibration and control purpose

Modeling of diesel oxidation catalysts for calibration and control purpose

An empirical approach to predicting heat transfer within single- and twin-skin automotive exhaust systems

The use of multi-variate models for the prediction of heat transfer in vehicle exhaust systems

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