Modeling Study of Active Regeneration of a Catalyzed Particulate Filter Using One-Dimensional DOC and CPF Models Michigan Technological Univ

Format:

Conference/Event

Author/Creator:

Surenhalli, Surenhalli, author.

Contributor:

Johnson, John H.

Parker, Gordon

Premchand, Kiran

Conference Name:

SAE 2011 World Congress & Exhibition (2011-04-12 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

The catalyzed particulate filter (CPF), used in conjunction witha diesel oxidation catalyst (DOC) is an important aftertreatmentdevice used to meet Environmental Protection Agency (EPA)heavy-duty diesel emission standards for particulate matter (PM).Numerical modeling of these exhaust after-treatment devicesdecreases the time and cost of development involved. Modeling CPFactive regeneration gives insight into the PM oxidation kinetics,which helps in reducing the regeneration fuel penalty. As seen fromexperimental data, active regeneration of the CPF results in asignificant temperature increase into the CPF (up to 8°C/sec) whichaffects the oxidation rate of particulate matter (PM). PM oxidationduring active regeneration was determined to be a function offilter PM loading, inlet temperature and inlet hydrocarbonconcentration.This paper focuses on the development and calibration of a1-dimensional, MATLAB/Simulink DOC model and its use with a CPFmodel appropriate for studying active regeneration strategies. TheDOC model accurately captures DOC behavior when the exhaust gas HCconcentration is at the elevated levels observed during CPF activeregeneration. Experimental data were used to calibrate the DOCmodel during CPF active regeneration using a numerical optimizationapproach. The DOC model is used to predict the time-varying outletHC concentrations which are then used as input to a 1-D CPFmodel.The CPF model is an improved version of the model described inPremchand and others, with several important differences including: HCand CO oxidation, reversible NO oxidation/NO2 dissociationreaction, PM cake layer permeability, PM cake layer density,improvements in the filtration model, wall and gas temperatureprediction and time-varying HC concentration into the CPF.The CPF modeling effort focuses on using the DOC outlet HCconcentration and calibrating the sub-models that have asignificant effect on the active regeneration pressure drop acrossthe CPF, including: HC oxidation, PM cake permeability, substratewall PM and PM cake oxidation and filtration. Comparisons are madebetween simulated and experimental values of the pressure dropacross the CPF and the PM oxidized during loading, regeneration andpost-loading, CPF outlet temperatures and CPF outlet gaseousemission concentrations for the selected load cases. Anoptimization has been done using the reaction rate from the CPFmodel to find thermal PM activation energy and pre-exponentialfactors.Active regeneration experimental data acquired by Chilumukuru etal., with a 2007 production Cummins regenerative particulate filterhas been used for this study. The experimental matrix consists ofthree CPF inlet temperatures (525, 550 and 600°C), three filterloadings (1.1, 2.2 and 4.1 g/l) and PM oxidation levels of 40 and70% of the PM retained at the end of loading. Accurate estimates ofthe DOC inlet HC levels are critical for accurate DOC and CPF modeltemperature predictions. A combined direct/indirect HC measurementapproach was used. Emission FID HC measurements were adjusted usinga DOC/CPF energy balance based on DOC and CPF inlet and outlettemperature measurements

Notes:

Vendor supplied data

Publisher Number:

2011-01-1242

Access Restriction:

Restricted for use by site license