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Impact of Fuel Quality variation on DOC & DPF system Performance - A case
study using GT-SUITE After-treatment Simulation Model
Dibakar MahalanabishRobert Bosch Engineering & Business Solutions Pvt. Ltd.
GT Conference 2015, Pune
1
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Contents
Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
2
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reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
3
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Objective:
• To simulate the impact of fuel quality variation
(sulfur content of fuel) on the performance of
Exhaust After-treatment devices (DOC & DPF).
Adopted Methodology:
• Qualitative validation of GT SUITE after-treatment models through case study simulations
• Providing user-defined reactions for the DOC model to address additional sulfur poisoning reactions
• Simulation of DOC with user-defined reactions to analyze impact of sulfur poisoning on light-off temperature for HC and NOx
Introduction
4
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Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
5
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reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
6
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reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Location of Temperature
Measurement
Simulation Results for variation of Temperature inlet of DOC & DPF during post injection
7
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Retarding Post-injection increases exhaust gas temperature at the inlet of DOC.
Retarding post-injection to 75º after TDC increases DOC inlet temperature by approximately 50º C.
Comparing DPF inlet temperature (DOC outlet) it is observed that temperature at DPF inlet is slightly higher than DOC
inlet for all the cases. This can be attributed to exothermic reactions inside DOC.
Simulation Results for variation of Temperature inlet of DOC & DPF during post injection
DOC Inlet Temperature DPF Inlet Temperature
8
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reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
9
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Though, post-injection is one of the viable
solution for DPF active regeneration, it increases
the amount of unburnt hydrocarbon substantially.
Post-injection also has negative influence on
fuel economy.
Simulation Results for Effect of Post-Injection on HC Emission and BSFC
Simulation of Effect of Post-Injection on HC Emission
Simulation of Effect of Post-Injection on BSFC
10
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Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
11
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0
25
50
75
100
300 350 400 450 500 550 600 650 700
CO
Co
nvers
ion
Eff
icie
ncy (
%)
Temperature (K)
Active_Surface_Site_Density = 0.3 mol/m^3
Active_Surface_Site_Density = 0.06 mol/m^3
Active_Surface_Site_Density = 0.012 mol/m^3
0
25
50
75
100
400 450 500 550 600 650 700 750 800
HC
Co
nvers
ion
Eff
icie
ncy (
%)
Temperature (K)
Active_Surface_Site_Density = 0.3mol/m^3
Active_Surface_Site_Density = 0.06mol/m^3
Active_Surface_Site_Density =0.012 mol/m^3
One of the critical aspect related to performance of exhaust after-treatment devices is aging which is effectively reduction in
number of site elements on the washcoat material.
Though there is no specific parameter relating Aging of these devices in GT SUITE models, it is observed that reduction in
the active surface density can replicate performance of aged catalyst after suitable correlation.
Simulation Results for Performance of an Aged Catalyst
12
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Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
13
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0
2
4
6
8
10
12
14
0 5000 10000 15000
Pre
ssu
re D
rop
(K
Pa)
Time (s)
Clean Filter
Initial Soot Load = 22 g
Initial Soot Load = 44 g
Initial Soot Load = 64 g
Simulation of Pressure Drop across DPF with different initial soot Load
0
1
2
3
4
5
6
7
0 10 20 30 40 50 60 70
Pre
ssu
re D
rop
(K
pa)
Soot Loading (g)
Deep-Bed
Simulation of Pressure Drop Characteristics
Simulation Results for Pressure Drop Characteristics across DPF
14
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reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
15
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reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0 5000 10000 15000 20000
So
ot
Layer
Th
ickn
ess (
mm
)
Time (s)
At Location X = 0.0
At Location X = 0.25
At Location X = 0.5
At Location X = 0.75
At Location X = 1.0
Simulation of Growth of Soot Layer Thickness along DPF
Though theoretically four different soot distributions are
possible, the most common profile suggested in literature is
parabolic.
GT SUITE model also has reported parabolic soot distribution
along the length of DPF.
Simulation Results for Growth of Soot Layer Thickness along DPF
0.08
0.09
0.1
0.11
0.12
0 0.25 0.5 0.75 1
So
ot
Layer
Th
ickn
ess (
mm
)
Normalized DPF Length
SIMULATED SOOT LAYER THICKNESS DISTRIBUTION
16
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Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
17
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Impact on DOC Performance
1. Presence of sulfur in diesel fuel results in SO2 in exhaust
gas. The catalysts in DOC facilitate the oxidation of SO2
and produce SO3. This oxidation suppresses the
necessary reactions of the toxic components of exhaust
gas (CO, HC and PM).
2. SO2 increases light-off temperature of the catalyst
substantially.
3. SO2 reacts with the wash coat material of DOC and
creates stable sulfur compounds which reduces the
quantity of active site elements and in turn reduces the
DOC conversion efficiency.
Impact on DPF Performance
1. Presence of sulfur increases the activation temperature of regeneration reaction and results in soot particles burning at higher
temperature.
2. SO3 reacts with water vapor of the exhaust gas and forms H2SO4 particles which emit through the exhaust path.
Problem Statement: Effect of Sulfur Poisoning on DOC and DPF
18
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Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
19
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DOC configuration in GT SUITE
To simulate sulfur poisoning effect, existing
GT model has to be reconfigured by adding
the additional reactions due to sulfur presence.
Reactions has to be
defined in this component
Activity Data Required
Sulfur
Poisoning
Simulation
Temperature of exhaust gas at the inlet & outlet of DOC
Exhaust mass flow rate
Composition of exhaust gas at the inlet of DOC (CO, NOx, SO2 , HC, O2 etc)
Geometrical characteristics of the catalyst: Length, Frontal Area, CPSI
Chemical characteristics of the catalyst: Site element used (PGM/ Zeolite),
Loading of site elements (g/cm3).
DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
20
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Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
21
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Trends in shift of light-off temperature is observed to be followed by initial simulation results.
This indicates that inclusion of sulfurpoisoning reactions has slowed downoxidation reactions inside DOC
(Junhui et al, 2013)
(Luo et al, 2010)
𝑻𝟓𝟎 = 𝟏𝟔𝟖º 𝑪
𝑻𝟓𝟎 = 𝟏𝟗𝟔º 𝑪
Initial Simulation Results on Sulfur Poisoning of DOC
22
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Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
23
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Comparison of HC Conversion
Efficiency (%)
Comparison of DOC Outlet
Temperature (º C)
DOC Inlet Temperature
Composition of Exhaust gas at DOC Inlet
Exhaust Volume flow rate
GT SUITE
DOC Model
Model tuning Approach
24
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reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
25
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350 ppm
50 ppm
The possible deviation may be due tothe variation of physical parametersof DOC (CPSI, frontal area etc.).
Maximum efficiency in simulation isfound to be lower than experiments.This may be due to assumptionsmade in the composition of NMHC(non-methane hydrocarbon).
Further fine tuning of the model withrespect to chemical kineticsparameters (activation energy, pre-exponent multiplier) will result inimproved accuracy.
50 ppm
350 ppm
Comparison of Simulation Results with Test Bench Data
26
Experiments are carried out on a 4-cylinder turbocharged engine
RBEI | 07/12/2015 | © Robert Bosch Engineering and Business Solutions Private Limited 2015. All rights reserved, also regarding any disposal, exploitation,
reproduction, editing, distribution, as well as in the event of applications for industrial property rights.
Introduction
Case Study Simulations:
• Variation of Temperature inlet of DOC & DPF during post injection
• Effect of Post-Injection on HC Emission and BSFC
• Performance of an Aged Catalyst
• Pressure Drop Characteristics across DPF
• Growth of Soot Layer Thickness along DPF
Sulfur Poisoning Simulations:
• DOC Configuration for Sulfur Poisoning Simulation in GT SUITE
• Initial Simulation Results on Sulfur Poisoning of DOC
• Model tuning Approach
• Comparison of Simulation Results with Test Bench Data
Conclusions
Contents
27
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Case Study Simulations:
GT-SUITE After-treatment models are capable of replicating true physical behaviours of after-treatment
devices.
Sulfur Poisoning Simulations:
GT-SUITE After-treatment models can be effectively used to simulate the impact of sulfur poisoning on the
performance of DOC and DPF.
In future findings of these simulations can be utilized in development of improved functionalities on ECU for
predicting performance deterioration of exhaust after-treatment devices due to fuel quality variations.
Conclusions
28
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I would like to thank the following people for their help during this work:
• Mr. Pradeep Kumar Keloth, Department Head, EEI, RBEI
• Mr. Aurobbindo Lingegowda, Project Manager, EEI4, RBEI
• Mr. Samrat G K, Expert, EEX, RBEI
Acknowledgements
29
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• Junhui, L., Kumar, A., Chen, X., Currier, N., Yezerets, A. (2013) Impact of Different Forms of Sulfur Poisoning on Diesel
Oxidation Catalyst Performance, SAE International doi:10.4271/2013-01-0514
• Luo, J., Kisinger, D., Abedi, A., Epling, W. (2010) Sulfur release from a model Pt/Al2O3 diesel oxidation catalyst:
Temperature-programmed and step-response techniques characterization, Appl. Catal. A: Gen. 383 (2010) 182-191
• Cabello, G. F., Laresea, C., Mariscala, R., Granadosa, M. L., Fierroa, J. L. G., Fernandez, R. R., Furio, M. (2004)
Deactivation on vehicle-aged diesel oxidation catalysts, Topics in Catalysis Vols. 30/31, July 2004.
References
30
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Thank You!
31