R R Final Update on APBF-DEC EGR/DPF/SCR Demonstration Project at SwRI Final Update on APBF-DEC EGR/DPF/SCR Demonstration Project at SwRI Chris Sharp, Magdi Khair - Southwest Research Institute Ralph McGill – Sentech DEER Conference - Chicago, IL - August, 2005 Chris Sharp, Magdi Khair - Southwest Research Institute Ralph McGill – Sentech DEER Conference - Chicago, IL - August, 2005 Southwest Research Institute Southwest Research Institute R R
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Final Update on APBF-DEC EGR/DPF/SCR Demonstration Project … · 2014. 3. 10. · Nitrous oxide--Nitrous oxide--Steady-State & Transient --At the 6000-hour PointSteady-State & Transient
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Final Update on APBF-DEC EGR/DPF/SCR Demonstration Project
at SwRI
Final Update on APBF-DEC EGR/DPF/SCR Demonstration Project
at SwRI
Chris Sharp, Magdi Khair - Southwest Research InstituteRalph McGill – Sentech
DEER Conference - Chicago, IL - August, 2005
Chris Sharp, Magdi Khair - Southwest Research InstituteRalph McGill – Sentech
DEER Conference - Chicago, IL - August, 2005
Southwest Research Institute
Southwest Research Institute
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ObjectivesObjectivesTo Demonstrate The Low Emissions Performance of Advanced Diesels+Urea SCR+DPF (2 Different Systems)
To Determine The Regulated And Unregulated Emissions W. &W/O Emission Controls
To Examine The Emission Control System Durability over 6,000 hours
To Sample Toxic Emissions For Analysis By Outside Lab
To Evaluate Sensitivities of The Control System Performance To Fuel Variables
System A NOSystem A NOxx apparent apparent degradation through 4000 hours, degradation through 4000 hours, performance restored at 6000 performance restored at 6000 hourshours
System B NOSystem B NOxx apparent apparent degradation at 6000 hour pointdegradation at 6000 hour point
Higher PM levels for ESC due to Higher PM levels for ESC due to high temperatures at DPF inlet high temperatures at DPF inlet (sulfate production)(sulfate production)
NONOxx
PMPM**
**PrePre--2007 Type PM Measurement System2007 Type PM Measurement System
System A NOx Diagnostics- ESC, 6000-Hr PointSystem A NOx Diagnostics- ESC, 6000-Hr Point
Gradual Loss of NOGradual Loss of NOxx Conversion with each test (similar behavior seen at Conversion with each test (similar behavior seen at 20002000--hr and 4000hr and 4000--hr test points)hr test points)
Recovery of conversion following highRecovery of conversion following high--NONOxx burnburn--outout
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System A NOx Diagnostics- ConclusionsSystem A NOx Diagnostics- Conclusions
SCR Catalyst deactivation was real (though apparently reversible) and present on both legs equally at 2000-Hr and 4000-Hr points
Catalyst deactivation was reversed at start of 6000-Hr point
During test episodes, progressive loss of conversion from test to test observed following initial stable period
Overall NH3-to-NOx ratio is ~ 1.02 for ESC calibrationDeactivation reversed at high temperature (> 400 C) with excess NOx(NH3:NOx < 0.5)
Recovery during 4000-6000 durability during a period of high engine-out NOx following an EGR cooler problem (major hint)Recovery during deliberate experiment at 6000-Hr point
Temporary deactivation of SCR catalyst during periods of excess NH3dosing*
No apparent thermal degradation of SCR catalysts after 6000 Hours
* Matches with contents of invited talk by Oliver * Matches with contents of invited talk by Oliver KroecherKroecher, Paul , Paul ScherrerScherrer Institute,Institute,CLEERS Symposium, Dearborn, MI, May 2005CLEERS Symposium, Dearborn, MI, May 2005
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System B Backpressure - Durability Engine, ESC Mode 10System B Backpressure - Durability Engine, ESC Mode 10
Loss of Passive Loss of Passive Regeneration on LeftRegeneration on Left--Side Side DPFDPF
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System B NOx Diagnostics- ConclusionsSystem B NOx Diagnostics- Conclusions
Left-side DPF appears to have lost passive regeneration during aging
Increased backpressure on left-side branch caused flow imbalance with more exhaust on right side
Right side → Not enough ammonia → lower conversionLeft side → Too much ammonia → Ammonia slip (to NOx in CUC*)Dual legs are a problem again
Increased engine backpressure resulted in higher catalyst temperaturesSCR temperatures in Modes 3-7 up from 490 C to 520 CLower NOx conversion due to higher temperatures (no effect on transient)
Loss of conversion related to DPF problem
No apparent thermal degradation of SCR catalysts after 6000 hours
** CUC =CUC = CleanClean--up Catalystup Catalyst
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Nitrous oxide--Steady-State & Transient --At the 6000-hour PointNitrous oxide--Steady-State & Transient --At the 6000-hour Point
4.4
6.5
2.1
4.5
0.0
2.0
4.0
6.0
8.0
10.0
Ave
rage
Raw
N2O
, ppm
System A System B
Transient ESC
0.0300.036
0.017
0.032
0.00
0.02
0.04
0.06
0.08
N2O
, g/h
p-hr
System A System B
Transient ESC
Tailpipe NTailpipe N22O levels are roughly O levels are roughly 10% of tailpipe NO10% of tailpipe NOxx levellevel
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Ammonia Slip--Steady-State & Transient --At the 6000-hour PointAmmonia Slip--Steady-State & Transient --At the 6000-hour Point
0.5 0.4 0.9
6.0
0.0
2.0
4.0
6.0
8.0
10.0
Ave
rage
Raw
NH
3, p
pm
System A System B
Transient ESC
0.002 0.002 0.003
0.015
0.00
0.01
0.02
0.03
0.04
NH
3, g
/hp-
hr .
System A System B
Transient ESCNHNH33 levels are roughly levels are roughly equivalent to DPFequivalent to DPF--out out
particulate levelsparticulate levels
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Transient BSFC increase of roughly 1-2% vs Base Engine*
ESC BSFC increase of roughly 4-5% vs Base Engine*
Most, if not all of the increase is due to EGR+DPF
Urea Consumption as percentage of fuel consumptionSystem A ~ 1.8% transient and ~ 3.8% ESC (all +/- 0.2%)System B ~ 1.4% transient and ~ 3.2% ESC (all +/- 0.2%)
Fuel and Urea ConsumptionFuel and Urea Consumption