Abstract
A 2013 6.7L Cummins ISB (209 kW) diesel engine was used to quantify the NO, NO2, and NOx storage and release performance of the diesel cold start catalyst (dCSC™). The NOx storage experiments were performed over a range of temperatures from 80 to 250°C and NOx release experiments were performed at temperatures from 200 to 450°C. A 2-D diesel cold start catalyst (d-CSC) model was developed to predict NO, NO2 storage, and release characteristics along with the temperature distribution within diesel cold start catalyst (d-CSC) and the pressure drop across the d-CSC. This d-CSC model was calibrated using eight runs of experimental data that consisted of storage temperatures ranging from 80 to 250°C and release temperatures ranging from 200 to 450°C. The validation results show that the new d-CSC model can predict 200-s NOx storage and total NOx release capacity with a maximum root mean square (RMS) error of 0.02 and 0.10 NO2 g/L of substrate, respectively. The NO2/NOx ratio RMS error was within 24%. The RMS temperature errors for storage and release phases were within 3°C and the pressure drop model error was within 0.2 kPa. It is found that the dCSC™ shows significant low temperature NOx storage capability with a peak storage occurring from 125 to 150°C. The rapid NOx release was observed at temperatures above 200°C which is well within the operating range of the aftertreatment system after cold start period.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- ANPR:
-
Advanced notice of proposed rule
- CARB:
-
California Air Resources Board
- CPF:
-
Catalyzed particulate filter
- CO:
-
Carbon monoxide
- CO2 :
-
Carbon dioxide
- CTI:
-
Clean Truck Initiative
- dCSC™:
-
Diesel cold start catalyst
- d-CSC:
-
Diesel cold start catalyst model (Johnson-Matthey)
- DOC:
-
Diesel oxidation catalyst
- DPF:
-
Diesel particulate filter
- ECU:
-
Electronic control unit
- EPA:
-
Environmental Protection Agency
- FTP:
-
Federal test procedure
- HC:
-
Hydrocarbons
- LLC:
-
Low load cycle
- MECA:
-
Manufacturers of Emission Controls Association
- MTU:
-
Michigan Technological University
- NO:
-
Nitrogen monoxide
- NO2 :
-
Nitrogen dioxide
- NOx:
-
Oxides of nitrogen
- O2 :
-
Oxygen
- OBD:
-
On-board diagnostics
- PM2.5:
-
Particulate matter of 2.5 micrometers and smaller
- PNA:
-
Passive NOx Adsorber
- RMC:
-
Ramp modal cycle
- RMS:
-
Root mean square
- SCAQMD:
-
South Coast Air Quality Management District
- SCR:
-
Selective catalytic reduction
- SCRF™:
-
SCR catalyst on a filter (Johnson-Matthey)
- SCR-F:
-
Selective catalytic reduction catalyst on a DPF
- SET:
-
Supplemental emission test
- SwRI:
-
Southwest Research Institute
- \(\Delta\) P:
-
Pressure drop
- 1-D:
-
One-dimensional
- 2-D:
-
Two-dimensional
- 3-D:
-
Three-dimensional
Abbreviations
- \({A}_{ads, NO}\) :
-
Pre-exponential for NO adsorption [m3 gmol−1 s−1]
- \({A}_{{ads, NO}_{2}}\) :
-
Pre-exponential for
- \(N{\mathrm{O}}_{2}\) :
-
adsorption [m3 gmol−1 s−1]
- \({A}_{ads,y}\) :
-
Pre-exponential of species
- \(\mathrm{y}\) :
-
for adsorption [m3 gmol−1 s−1]
- \({A}_{des, NO}\) :
-
Pre-exponential for NO desorption [m3 gmol−1 s−1]
- \({A}_{{des, NO}_{2}}\) :
-
Pre-exponential for NO desorption [m3 gmol−1 s−1]
- \({A}_{des,y}\) :
-
Pre-exponential of species
- \(\mathrm{y}\) :
-
for desorption [m3 gmol−1 s−1]
- \({A}_{amb}\) :
-
Surface area of outer shell [m2]
- \({A}_{g}\) :
-
Geometric surface area [m2]
- \({Ar}_{i,j}\) :
-
Area normal to the heat transfer in the radial direction [m2]
- \(a\) :
-
Channel width [m]
- \({CFA}_{i,j}\) :
-
d-CSC frontal area at each zone [m2]
- \({C}_{{f}_{i,j}}\) :
-
Skin friction coefficient [-]
- \({c}_{f}\) :
-
Specific heat of d-CSC substrate material [J kg−1 K−1]
- \({C}_{{C}_{3}{H}_{6}}\) :
-
d-CSC inlet
- \({C}_{3}{H}_{6}\) :
-
concentration [mol m−3]
- \({C}_{CO}\) :
-
d-CSC inlet
- \(CO\) :
-
concentration [mol m−3]
- \({C}_{{H}_{2}O}\) :
-
d-CS inlet
- \({H}_{2}O\) :
-
concentration [mol m−3]
- \({C}_{NO}\) :
-
d-CSC inlet
- \(NO\) :
-
concentration [mol m−3]
- \({C}_{{NO}_{2}}\) :
-
d-CSC inlet
- \({NO}_{2}\) :
-
concentration [mol m−3]
- \({C}_{s,y}\) :
-
Solid phase concentration for the species
- \(y\) :
-
[mol m−3]
- \({C}_{s,NO}\) :
-
d-CSC substrate
- \({NO}\) :
-
concentration [mol m−3]
- \({C}_{s,NO2}\) :
-
d-CSC substrate
- \({NO}_{2}\) :
-
concentration [mol m−3]
- \({C}_{{O}_{2}}\) :
-
d-CSC inlet
- \({O}_{2}\) :
-
concentration [mol m−3]
- \({c}_{{p}_{i,j}}\) :
-
Specific heat of exhaust gas at each zone [J kg−1 K−1]
- \({C}_{s,y}\) :
-
d-CSC solid concentration along y direction [mol m−3]
- \({C}_{g,y}\) :
-
d-CSC gaseous concentration along y direction [mol m−3]
- \({D}_{h}\) :
-
Hydraulic diameter of the d-CSC channel [m]
- \({E}_{NO}\) :
-
Activation energy for
- \(\mathrm{NO}\) :
-
oxidation [J gmol−1]
- \({E}_{NO2}\) :
-
Activation energy for
- \({\mathrm{NO}}_{2}\) :
-
oxidation [J gmol−1]
- \({E}_{des,NO}\) :
-
Activation energy for
- \(\mathrm{NO}\) :
-
desorption [J gmol−1]
- \({E}_{{des,NO}_{2}}\) :
-
Activation energy for
- \(N{\mathrm{O}}_{2}\) :
-
desorption [J gmol−1]
- \({E}_{{des,NO}_{2}}\) :
-
Desorption activation energy for species
- \(\mathrm{y}\) :
-
[J gmol−1]
- \({G}_{4}\) :
-
Inhibition factor [-]
- \({h}_{amb}\) :
-
Ambient heat transfer coefficient [W m−2 K−1]
- \({h}_{g}\) :
-
Internal heat transfer coefficient [W m−1 K−1]
- \({K}_{i,j}\) :
-
Fanning friction factor [-]
- \(k\) :
-
Species reaction index [-]
- \({k}_{mtc,y}\) :
-
Mass transfer coefficient of species
- \(\mathrm{y}\) :
-
[m2 s−1]
- \({K}_{p}\) :
-
Equilibrium constant [-]
- L:
-
Length of the d-CSC [m]
- M:
-
Number of radial zones [-]
- \(\dot{m}\) :
-
Instantaneous exhaust mass flow rate [kg s−1]
- \({\dot{m}}_{i,j}\) :
-
Mass flow rate at each zone [kg s−1]
- N:
-
Number of axial zones [-]
- \({N}_{y,k}\) :
-
Stoichiometric coefficient [-]
- \({N}_{u}\) :
-
Nusselt number [-]
- \({P}_{in}\) :
-
d-CSC inlet gas pressure [kPa]
- \({P}_{r}\) :
-
Prandtl number [-]
- \({\dot{Q}}_{cond,axial}\) :
-
Axial conduction [W]
- \({\dot{Q}}_{cond,radial}\) :
-
Radial conduction [W]
- \({\dot{Q}}_{conv}\) :
-
Convection between channels gases and substrate wall [W]
- \({\dot{Q}}_{rad}\) :
-
Radiation between channel surfaces [W]
- \({\dot{Q}}_{reac}\) :
-
Exothermic reactions within d-CSC [W]
- \({rc}_{i}\) :
-
Radial distance of the nodes [m]
- \(R\) :
-
Universal gas constant [J mol−1 K−1]
- \({R}_{{e}_{i,j}}\) :
-
Reynolds number [-]
- \({R}_{ads,y}\) :
-
Adsorption rate of species
- \(y\) :
-
[mol m−3 s−1]
- \({R}_{ads,NO}\) :
-
Adsorption rate of NO [mol m−3 s−1]
- \({R}_{ads,NO2}\) :
-
Adsorption rate of NO2 [mol m−3 s−1]
- \({R}_{des,y}\) :
-
Desorption rate of species
- \(y\) :
-
[mol m−3 s−1]
- \({R}_{des,NO}\) :
-
Desorption rate of NO [mol m−3 s−1]
- \({R}_{des,NO2}\) :
-
Desorption rate of NO2 [mol m−3 s−1]
- \({R}_{mat 1}\) :
-
Thermal resistance of the inner mat [K/W]
- \({R}_{mat 2}\) :
-
Thermal resistance of the outer mat [K/W]
- \({R}_{nfz}\) :
-
Thermal resistance of the no flow zone [K/W]
- \({R}_{shell 1}\) :
-
Thermal resistance of the inner shell [K/W]
- \({R}_{shell 2}\) :
-
Thermal resistance of the outer shell [K/W]
- \({R}_{total}\) :
-
Total thermal resistance of the insulation material [K/W]
- \({R}_{y,k}\) :
-
Reaction rate of species
- \(y\) :
-
[mol m−3 s−1]
- \({T}_{amb}\) :
-
Ambient temperature [K]
- \({Ts}_{i,j}\) :
-
Solid phase temperature at each zone [K]
- \({Tg}_{i,j}\) :
-
Gas phase temperature at each zone [K]
- \({u}_{{g}_{i,j}}\) :
-
Exhaust gas velocity [m s−1]
- \({\dot{V}}_{i,j}\) :
-
Actual volumetric flow rate of the channel [m3 s−1]
- \({V}_{{e}_{i,j}}\) :
-
Empty volume (volume occupied by the exhaust gas) at each zone [m3]
- \({V}_{{s}_{i,j}}\) :
-
Substrate volume with washcoat at each zone [m3]
- \({t}_{ins+can}\) :
-
Thickness of the insulation + inner can [m]
- \({T}_{amb}\) :
-
Ambient temperature [K]
- \({T}_{{g}_{i,j}}\) :
-
d-CSC solid phase temperature at each zone [K]
- \({T}_{in}\) :
-
d-CSC inlet temperature [K]
- \({T}_{{s}_{i,j}}\) :
-
d-CSC solid phase temperature at each zone [K]
- \({T}_{w}\) :
-
d-CSC substrate temperature at each zone [K]
- \(z\) :
-
Axial zone length [m
- \({\Delta }_{i}\) :
-
Effective radial zone radius [m]
- \({\Delta }_{j}\) :
-
Effective axial zone length [m]
- \({\Delta L}_{i,j}\) :
-
axial length of the channel at each zone [m]
- \({\Delta P}_{i,j}\) :
-
Pressure drop across d-CSC at each zone [kPa]
- \(\Delta x\) :
-
Discretization length in axial direction [m]
- \(\varepsilon\) :
-
Void fraction [-]
- \({\varepsilon }_{r}\) :
-
Emissivity of the metal surface [-]
- \({\theta }_{1,NO}\) :
-
Fraction of sites covered with NO molecules [-]
- \({\theta }_{1,NO2}\) :
-
Fraction of sites covered with NO2 molecules [-]
- \({\theta }_{y}\) :
-
Fraction of sites covered with species
- \(y\) :
-
[-]
- \({\lambda }_{i,j}\) :
-
Thermal conductivity of the substrate [W m-1 K−1]
- \({\mu }_{{g}_{i,j}}\) :
-
Dynamic viscosity of exhaust gas [Ns m−2]
- \({\mu }_{i,j}\) :
-
Dynamic viscosity of exhaust gas at each zone [Ns m−2]
- \({\rho }_{f}\) :
-
d-CSC substrate density [kg m−3]
- \({\rho }_{{g}_{i,j}}\) :
-
Exhaust gas density [kg m−3]
- \(\sigma\) :
-
Stefan-Boltzman constant [W m-2 K−4]
- \({\tau }_{wall}\) :
-
Wall shear stress [N m−2]
- \({\Omega }_{1, NO}\) :
-
Total storage capacity of NO sites [gmol m−3]
- \({\Omega }_{1, NO2}\) :
-
Total storage capacity of NO2 sites [gmol m−3]
- \({\Omega }_{y}\) :
-
Total storage capacity of species
- \(y\) :
-
[gmol m−3
- i :
-
Radial Direction
- j :
-
Axial Direction
- y :
-
Species Index
- k :
-
Reactions Index
References
Mobile Source Control Division Staff.: California Air Resources Board staff current assessment of the technical feasibility of lower NOx standards and associated test procedures for 2022 and subsequent model year medium-duty and heavy-duty diesel engines, California Air Resources Board Staff White Paper, (2019). https://ww2.arb.ca.gov/sites/default/files/classic/msprog/hdlownox/white_paper_04182019a.pdf (last accessed 02/12/2022)
California Air Resource Board.: Notice of public hearing to consider the proposed heavy-duty engine and vehicle omnibus regulation and associated amendments, (2020). https://ww3.arb.ca.gov/regact/2020/hdomnibuslownox/notice.pdf (last accessed 12/27/2020)
Environmental Protection Agency.: Advanced Notice of Proposed Rulemaking, Federal Register, Vol. 85, No., (2020). https://www.govinfo.gov/content/pkg/FR-2020-01-21/pdf/2020-00542.pdf (last accessed on 12/27/2020)
Sharp, C.A., Webb, C.C., Neely, G.D, Smith, I.: “Evaluating Technologies and Methods to Lower Nitrogen Oxide Emissions from Heavy-Duty Vehicles”, Southwest Research Institute (SwRI) Project No. 19503 Final Report (2017).
Sharp, C.: Heavy-Duty low NOx demonstration programs at SwRI-CARB workshop Presentation, Southwest Research Institute, (2019). https://ww2.arb.ca.gov/sites/default/files/classic/msprog/hdlownox/files/workgroup_20190926/guest/swri_hd_low_nox_demo_programs.pdf (last accessed on 12/27/2020)
Chen, H., Mulla, S., Weigert, E., Camm, K., Ballinger, T., Cox, J., and Blakeman, P.: Cold start concept (CSCTM): a novel catalyst for cold start emissions control. SAE Int. J. Fuels Lubr. 6(2), (2013). 10.4271/2013-01-0535.
Chen, H., Liu, D., Weigert, E., Cumaranatunge, L., Camm, K., Bannon, P., Cox, J., Arnold, L., Durability assessment of diesel cold start concept(dCSCTM) technologies. SAE Int. J. Engines, 10(4), (2017). https://doi.org/10.4271/2017-01-0955
Mortimer, M., Taylor, P.: Chemical kinetics and mechanism, Royal Society of Chemistry, First edition, ISBN 0854046704, (2002).
Rajaram, R.R., Chen H.Y., and Liu, D., Cold start catalyst and its use in exhaust systems, US Patent Application Publication No. US2015/0158023 A1, 2015.
Chen, H., Collier, J.E., Liu, D., Mantarosie, L., Duran-Martin, D., Novak, V., Rajaram, R.R., Thompsett, D.: Low temperature NO storage of zeolite supported Pd for low temperature diesel engine emission control. Catal Lett 2016(146), 1706–1711 (2016). https://doi.org/10.1007/s10562-016-1794-6
Vu, A., Luo, J., Li, J., Epling, W.S.: Effects of CO on Pd/BEA passive NOx adsorbers. Catal Lett 2017(147), 745–750 (2017). https://doi.org/10.1007/s10562-017-1976-x
Surenahalli, H.S., Premchand, K., Johnson, J., Parker, G.: Modeling study of active regeneration of a catalyzed particulate filter using one-dimensional DOC and CPF models, SAE Technical Paper No. 2011-01-1242, (2011). https://doi.org/10.4271/2011-01-1242
Song, X.: A SCR model based on reactor and engine experimental studies for a Cu-zeolite catalyst, PhD Dissertation, Michigan Technological University, (2013).
Mahadevan, B.S., Johnson, J.H., Shahbakhti, M.: Predicting pressure drop, temperature and particulate matter distribution of a catalyzed diesel particulate filter using multi-zone model including cake permeability. J Emission Control Sci Technolol 3(2), 171–201 (2017). https://doi.org/10.1007/s40825-017-0062-6
Chundru, V.R., Mahadevan, B.S., Johnson, J.H., Parker, G.G., Shahbakhti, M.: Development of a 2D model of a SCR catalyst on a DPF. Emission Control Sci Technol 15(2), 133–171 (2019). https://doi.org/10.1007/s40825-019-00115-4
Sampara, C.S., Bissett, E.J., Assanis, D.: Hydrocarbon storage modeling for diesel oxidation catalysts. Chem Eng Sci 63, 5179–5192 (2008)
Sampara, C.: Global reaction kinetics for oxidation and storage in diesel oxidation catalysts, PhD Dissertation, University of Michigan, (2008).
Premchand, K.: Experimental and modeling study of the filtration and oxidation characteristics of a diesel oxidation catalyst and a catalyzed particulate filters, MS Thesis, Michigan Technological University, (2006).
Berndt, C.T.: An experimental study of a passive NOx adsorber (PNA) for the reduction of cold start diesel emissions, MS Thesis, Michigan Technological University, (2019).
Gustafson, E.: An experimental investigation into NO2 assisted particulate oxidation with and without urea and active regeneration of particulate matter in a SCR catalyst on a DPF, MS Thesis, Michigan Technological University, (2016).
Kadam, V.: An experimental investigation of the effect of temperature and space velocity on the performance of a Cu-Zeolite flow-through SCR and a SCR catalyst on a DPF with and without PM loading, MS Thesis, Michigan Technological University, (2016).
Mahadevan, B.S., Johnson, H.J., and Shahbakhti.: Experimental and simulation analysis of temperature and particulate matter distribution for a catalyzed diesel particulate filter, J. Emission Control. Sci. Technol. 1(4), 255-283 (2015). https://doi.org/10.1007/s40825-015-0022-y
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Appendices
Appendix 1 Thermocouple Layout and Thermal Insulation Arrangement
Figs. 12
dCSC™ thermocouple layout
12,
Illustration of the dCSC™ thermal insulation arrangement
Appendix 2 Additional d-CSC Submodel Equations
2.1 Solid and Gas Phase Temperature Solver
In the substrate temperature submodel in Equation (1), \({\dot{Q}}_{cond.radial}\) at the outermost zone of the d-CSC model is calculated accounting for the multilayers of thermal insulation shown in Fig. 13. The \({\dot{Q}}_{cond.radial}\) at the outermost radial zone is give as
where, \({\lambda }_{i,j}\) is the thermal conductivity of the substrate, \({Ar}_{i,j}\) is the area normal to the heat transfer in the radial direction, \({Ts}_{i,j}\) is the substrate temperature,\({rc}_{i}\) is the radial distance of the nodes, \({T}_{amb}\) is the ambient temperature, \({R}_{total}\) is the total thermal resistance of the insulation materials shown in Fig. A 2, \({R}_{nfz}\) is the thermal resistance of the no flow zone of the d-CSC, \({R}_{mat 1}\) is the thermal resistance of the inner mat, \({R}_{shell 1}\) is the thermal resistance of the inner shell, \({R}_{mat 2}\) is the thermal resistance of the outer mat , \({R}_{shell 2}\) is the thermal resistance of the outer shell, \({h}_{amb}\) is the ambient heat transfer coefficient, , \({A}_{amb}\) is the surface area of outer shell , \({\varepsilon }_{r}\) is the emissivity of the metal surface, and \(\sigma\) is the Stefan-Boltzman constant
2.2 d-CSC Species Solver Equations
Table
8 shows the summary of the chemical reactions and rate expressions used in the d-CSC species solver model.
Table 8
where \({R}_{ads,NO}\) is the adsorption rate of NO, \({R}_{ads,NO2}\) is the adsorption rate of NO2, \({R}_{des,NO}\) is the desorption rate of NO, \({R}_{des,NO2}\) is the desorption rate of NO2, \({A}_{ads,NO}\) is the NO adsorption pre-exponential, \({A}_{ads,NO2}\) is the NO2 adsorption pre-exponential, \({C}_{s,NO}\) is the sold phase concentration of NO, \({C}_{s,NO2}\) is the solid phase concentration of NO2, \({\theta }_{1,NO}\) is the fraction of sites covered with NO molecules, \({\theta }_{1,NO2}\) is the fraction of sites covered with NO2 molecules, \({\Omega }_{NO}\) is the total storage capacity of NO sites, \({\Omega }_{NO2}\) is the total storage capacity of NO2 sites, \({E}_{des,NO}\) is the activation energy for the NO desorption, \({E}_{des,NO2}\) is the activation energy for the NO2 desorption, \({A}_{NO}\) is the NO oxidation pre-exponential, \({A}_{NO2}\) is the NO2 oxidation pre-exponential, \({E}_{NO}\) is the activation energy for the NO oxidation reaction, \({E}_{NO2}\) is the activation energy for the NO2 oxidation reaction, \({C}_{O2}\) is the gaseous O2 concentration (gaseous concentration is used instead of solid phase concentration to reduce computational complexity and is available in excess in diesel exhaust), \({K}_{p}\) is the equilibrium constant, \(R\) is the universal gas constant, \({G}_{4}\) is the inhibition factor and \(Ts\) is the solid phase temperature of the d-CSC. The detailed formulation of terms used in Table 8 for NO oxidation equations are available in reference [18].
2.3 Pressure Drop Model
The pressure drop across the d-CSC is calculated using the fully developed laminar flow equations for a square channel from the previous research [18] and it is given as
where \({\Delta P}_{i,j}\) is the pressure drop across the channel at each zone \((i,j)\), \({\varepsilon }_{i,j}\) is the void fraction representing open frontal area at each zone, \({\mu }_{{g}_{i,j}}\) is the exhaust gas viscosity, \({K}_{i,j}\) is the fanning friction factor, \({\Delta L}_{i,j}\) is the axial length of the channel at each zone, \({\dot{V}}_{i,j}\) is the actual volumetric flow rate of the channel, \({CFA}_{i,j}\) is the frontal area at each zone, \({D}_{h}\) is the hydraulic diameter of the channel, \({C}_{{f}_{i,j}}\) is the skin friction coefficient, \({R}_{{e}_{i,j}}\) is the Reynolds number, \({\tau }_{wall}\) is the wall shear stress, \({\rho }_{{g}_{i,j}}\) is the gas density, \({u}_{{g}_{i,j}}\) is the exhaust gas velocity, \({D}_{h}\) is the hydraulic diameter of the channel and \({\mu }_{{g}_{i,j}}\) is the exhaust gas viscosity.
Appendix 3 d-CSC Model Calibration Parameters Summary
Tables
9,
10,
Appendix 4 Model Discretization Study – 3 × 3, 4 × 4 and 5 × 5 Models
The d-CSCTM temperature varies axially and radially as shown in Figure 14
Experimental temperature distribution for S250/R350 experiment at 108 min (2 min after the start of Phase IV)
14 for S250/R350 experiment. The experimental axial temperature variation is upto 12°C and the radial temperature variation is about 8°C. The simulation of axial and radial temperature distribution is necessary to accurately capture the storage and release charecterstics of the d-CSC. Based on the experimental data presented in Section 5 of this work, the 20°C variation in temperature could alter the 200-second storage capacity by 0.06 gNO2/L.sub (in 200-250°C storage temperature range) and release capacity by 0.08 gNO2/L.sub (comparing S080/R300 and S150/R200 experiments). Hence, in order to capture the temperature dependent storage and release charecterstics accurately, axial and radial distribution modelling is necessary. However, the higher level of model discretization increases the computational time. From earlier research by same authors, the computational time varies linearly with the number or elements used in the model [22]. In case of an 1-D 3x1 model (3 elements in total), with 3 axial discretization and 1 radial discretization, the computation time is 1/3rd of the 3x3 2-D model with 3 axial and 3 radial discretization (9 elements in total). Comparing 2-D 3x3 discretization with 2-D 10x10 discretization, 10x10 discretization will be 11 times slower than 3x3 model. The 3x3 d-CSC model used in this work for S250/R350 experiment took 70 hours to simulate 1.3 hours of test data. Hence, considering the accuracy and the computational time, the 3x3 axial and radial discretization was selected for 2-D d-CSC modeling presented in this research. The comparison of experimental and model temperature distribution for S250/R350 experiment at 3x3,4x4 and 5x5 discretization levels are shown in Figs. 14,
Model temperature distribution for S250/R350 experiment at 108 min (2 min after the start of Phase IV) – 3 × 3 Discretization
15,
Model temperature distribution for S250/R350 experiment at 108 min (2 min after the start of Phase IV) – 4 × 4 Discretization
16 and
Model temperature distribution for S250/R350 experiment at 108 min (2 min after the start of Phase IV) – 5 × 5 Discretization
17, respectively. The model discretization plots in Figs. 15, 16 and 17 shows that the 3x3 model is able to capture axial and radial distribution similar that of 5x5 model. Comparing 3x3, 4x4 and 5x5 models, the maximum temperature difference is about 8°C at the outer most radius (dCSCTM length of 122 mm and dCSCTM radius of 124 mm) between 3x3 and 5x5 models. The max difference in 200-second NOx storage capacity is about 0.07 gNO2/L.sub and the total NOx release capacity is about 0.02 gNO2/L.sub compared to 3x3 model.
Rights and permissions
About this article
Cite this article
Mahadevan, B.S., Berndt, C.T., Johnson, J.H. et al. Experimental and Modeling Study of NO and NO2 Storage and Release Characteristics of a Diesel-Cold Start Catalyst. Emiss. Control Sci. Technol. 8, 41–62 (2022). https://doi.org/10.1007/s40825-022-00208-7
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s40825-022-00208-7