b'Engineer Innovation | AutomotiveHow toSet-up and calibrate the after treatment of system modelsThe implementation of continuously evolving regulations, toward a drastic reduction of vehicle emissions, raises new engineering challenges and the need to more widely deploy exhaust system simulation over the development cycle. This cannot be done without a strong combination of modeling capabilities and methodologies supported by application-specific tools since after-treatment simulation remains as combustion, a hot topic involving complex cross-coupled phenomena.The benefits of using system simulation, to support the development of exhaust lines including pollutant abatementFigure 1: Simcenter Amesim Exhaust calibration tool is an interactive interface with a step by devices as well as their evaluation in astep workflowvehicle context, have been documented and demonstrated on many occasions.the conversion process is to be definedUser-defined species and reactions can However, the physical modeling of theand the associated chemical reactionsbe added to ensure more flexibility in catalytic converters using 0D/1Das well. In addition, changes incase of the reaction scheme is already approaches remains a delicate taskemissions regulations impact designsdefined.which, in most cases, requires specificand loadings which tend to increase the competences hardly compatible with acomplexity of the pollutant conversionOnce a kinetic scheme is determined, large deployment.chemistry. Hence, developing the rightthe actual model calibration process kinetic scheme becomes a challenge,can start. The first step is related to the The modeling capabilities of Simcenterespecially for non-experts. handling of the available test data.Amesim are leveraged by an application-oriented tool, the which supports andTo make this step more accessible forThe experimental data needed for the guides the user in the set-up andbroader user profiles, predefinedexhaust model calibration can be calibration of the aftertreatment systemchemical schemes for main knowngenerated either by a synthetic gas test models, toward an easier adoption byapplications are provided in the tool inbench or by engine/chassis non-experts. Indeed, as soon as thethe form of a database of chemicaldynamometers. They are uploaded in studied exhaust configuration isreactions (three-way catalyticthe tool and will be used as reference sketched with determined location ofconverter, diesel oxidation catalyst,for the actual model parameter tuning monoliths, pipes, gas analyzer andselective catalytic converter). step. Their quality and consistency are sensors, a well-structured methodologya trigger point for an efficient model can be applied. These predefined sets of reactions arecalibration. Hence, the test data should provided with their rate law formulasbe analyzed and pre-processed carefully After fixing the monolith geometry in(Langmuir Hinshelwood) which can beto ensure the calibration pertinence.terms of number of cells, wall thicknesscustomized according to the studied and monolith apparent density, thecase. Default values are given for theThe experimental data required are kinetic scheme involved in each of thetwo Arrhenius parameters mainly mass flow rates, temperatures monoliths is to be defined. This is a(pre-exponential factor and activationand species concentrations as a complex process for several reasons.energy) and can be used as a startingfunction of time. According to gas First, the list of species to be tracked inpoint for the calibration study.analyzers operation, a gas sample is 36'