Performance Evaluation of the Delphi Non-Thermal Plasma ... · PDF fileDynamics & Propulsion...
Transcript of Performance Evaluation of the Delphi Non-Thermal Plasma ... · PDF fileDynamics & Propulsion...
Dynamics & Propulsion Innovation Center
Performance Evaluation of the Delphi Non-Thermal Plasma System Under Transient and Steady State Conditions
8th Diesel Engine Emission Reduction ConferenceSan Diego, CaliforniaAugust 25-29, 2002
Joseph V. Bonadies, Joachim Kupe, Galen B. Fisher, Craig L. DiMaggio, David A. Goulette, Thomas W. Silvis, Mark Hemingway, William J. LaBarge
Delphi Corporation
Darrell R. Herling, Monty R. Smith, John G. Frye, Mark A. GerberPacific Northwest National Laboratory
Dynamics & Propulsion Innovation Center
Acknowledgements
California Energy Commission Diesel Emissions Carl Moyer Demonstration Program
Jerry Wiens
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Test Vehicle ConfigurationNTP Assisted Catalyst Evaluation
u 2000 European production vehicle with 2.2 L common rail engine – Delphi development EMS– Production FIE– Euro 3 emission certification
u System Configuration – DPF + Reactor + Catalysts
u 20 Cell Parallel Plate NTP Reactor– 15.4cc active area
u 2.5 liter SiC DPF (non-catalyzed)
u DeNOx Catalyst (Stabilized)– Ag Al2O3 (1.67L) (Catalyst 1)– Ag Ba-Y-Z (3.35L) (Catalysts 2 & 3)– Pt oxidation (0.98L) (Catalyst 4)
u Power Supply – 220VAC – Power control based on Speed/Load– 15KHz Pulse Density Modulation (PDM)– Power supply efficiency 80% from wall to gas
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Pulse Density Modulation (PDM)Power Delivery Control
u Pulse density modulation power control– Fixed Amplitude (6kV peak)– Automatic resonant frequency control (Fc » 15 – 20 kHz)– Variable repetition rate based on speed/load
u US Patent 6,423,190 pulse density modulation for uniform barrier discharge in a non-thermal plasma reactor
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Vehicle Exhaust Configuration
56cm6689
99119127142158
Catalyst NTP DPF
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Time(sec)
NO
->N
O2
Co
nve
rsio
n (%
)
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Tem
per
atu
re (d
eg C
)
Reactor Efficiency
Reactor Inlet Temp
Vehicle Speed
NTP Reactor EfficiencyMVEG Cycle
• NO to NO2 conversion > 90% over ECE
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Net NTP ReactorNO Conversion Efficiency
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Time (s)
Cu
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lati
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O (
g)
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Wh
slp
d(k
ph
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NO Reactor In CumulativeNO Reactor Out CumulativeWhlspd
67%
80%
• 80% cumulative NO to NO2 conversion up to mid EUDC• 67% cumulative NO to NO2 overall
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Time(sec)
NO
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m),
NO
x(p
pm
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ehic
le S
pee
d(k
ph
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NO
NOx
HC
Vehicle Speed
In-cylinder Post Injection TimingNTP Reactor Outlet
• Transient control provides HCs from post injection that arrive at plasma and catalyst ahead of NOx spike
Post Injected HC
Modal NOx
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Time
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wer
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ts),
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icle
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eed
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h)
Avg Wall Power
Avg Reactor Power
Vehicle Speed
NTP Power Consumption
• Transient control of NTP power demonstrated• 350 Watt average over MVEG
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Fuel Economy Penalty
u Power Consumption– Fuel Economy Penalty: 5 %
u Post Injected HC– Fuel Economy Penalty: 3 %
u Total Fuel Economy Penalty = 8 %
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Time(sec)
NO
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Engine Out NOx
Tailpipe NOx
Catalyst Inlet Temp
Catalyst Outlet Temp
Vehicle Speed
Adsorption Desorption NOx Reduction
NOx Concentration ECE
Prep: 3 hot MVEG + cold soak
• NOx adsorption, desorption, and then reduction through ECE cycle
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Time(sec)
NO
x(p
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Engine Out NOx
Tailpipe NOx
Catalyst Inlet Temp
Catalyst Outlet Temp
Vehicle Speed
NOx Concentration EUDC
• Low NOx efficiencies during high speed portion of EUDC• Large NOx desorption during final deceleration
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Catalyst Bed TemperaturesC395 MVEG Run #470 Stabilized ABBP Catalyst - Run #1
w/ NTP & w/ Diesel Post InjectionCatalyst Temperatures
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Catalyst INCatalyst OutVehicle SpeedCat 1Cat 2Cat 3Cat 4
• Catalyst bed temperatures stay below 300° C until last 100 s of MVEG• Emphasizes the performance of the low temperature zeolite catalyst
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Catalyst Temperature (C)
NO
x R
edu
ctio
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ffic
ien
cy (%
)
SGB Concentration200 ppm NO500 ppm C3H610% O25% H2O7% CO2Balance N2
Test ConditionWith NTP at a constant 150CSV = 38k/h for each brick or
19k/h total
Synthetic Gas Bench (SGB) Catalyst Performance
NOx Reduction Efficiency of Ag-alumina + Ag-Ba-Y-zeolite Catalyst(1 washcoated brick of the alumina followed by 1 brick of the zeolite)
• Synthetic gas bench (SGB) testing used to identify candidate catalysts
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Engine Dyno Steady State PerformanceC3H6 vs Post Injection - 150°C
Stabilized Catalyst1200 RPM, 27Nm, 97ppm NO, 150ppm NOx
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Ag Al2O3 Ag Ba Y Zeolite
NO
x C
on
vers
ion
(%)
w/ 500 ppm C3H6 w/NTP stabilized
w/ Post Injection w/NTP stabilized
Performance with C3H6agrees with SGB testing
Space VelocityAg Al2O3 40k/hrAg BaYZ 20k/hr
• With HC from post-injection, <20% NOx conversion • 50% NOx conversion similar on dyno and SGB with 500 ppm propene• Near 15% with only propene & no NTP
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Engine Dyno Steady State PerformanceC3H6 vs Post Injection - 350°C
Dyno TestingStabilized Catalyst
2000 RPM, 68Nm, 200ppm NO, 200 ppm NOx
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Ag Al2O3 Ag Ba Y Zeolite
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Performance with C3H6 < half of SGB testing at 38 K h-1
w/ 500 ppm C3H6 w/NTP stabilized
w/ Post Injection w/NTP stabilized
Space VelocityAg Al2O3 100k/hrAg BaYZ 50k/hr
• With HC from post-injection, negative NOx conversion • NOx conversion @ 100 K h-1 SV expected to be less than SGB data @ 38 K h-1
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NTPR Acetaldehyde ProductionEngine Dyno Steady State
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NTP inlet Temp (C)
CH
3CH
O P
rod
uct
ion
(p
pm
)
PostInject
Propene
Acetaldehyde is the most efficient reductant used by these NOx catalysts
• With post injection, insufficient appropriate HC species exist in the exhaust to yield sufficient acetaldehyde
[97 ppm EO NO] [200 ppm EO NO]
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u 15 % NOx total system efficiency over MVEG cycle – 30 % ECE, 3% EUDC– NOx adsorption and desorption affected catalyst efficiencies– Ag Al2O3 catalyst not fully exercised due to low exhaust temperature
u Reactor exhibits good NO->NO2 conversionuGreater than 85% HC and 62% CO efficiency on cold
MVEG with low temperature oxidation catalyst as rear bricku Diesel post injection calibration improved reactor efficiency
during transientsuModest power levels are seen at low speed/load steady
state operating points
Vehicle Test Summary
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DP
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p (
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t Loa
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NTP-DPF DPF only NTP-DPF Soot DPF only Soot
26.6 gms
38.1 gms
11.0 kPa
6.7 kPa
7.3
9.5
30.1
20.2
12.8 14.6 17.719.1
21.7 24.2
EO NOx: 347 ppm EO NO: 301 ppm EO HC: 22 ppm
Speed / Load: 2000 RPM / 85 Nt m Engine Flow: 43 gm/sec
EO PM: 1.7 gm/hr No EGR DPF (Type / Size): SiC / 4.1 liter
Reactor Power: 600 Watts Reactor NO2 Efficiency: 16.2%
DPF Regeneration305 C DPF Inlet Temperature
• Continuous regeneration occurs at 305 C with ~100 ppm NO2 in exhaust • DPF backpressure and soot loading reduced with NTP compared to DPF only
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DPF RegenerationSummary
u NTP reactor reduces exhaust PM mass 20% to 30%
u Continuous regeneration of a non-catalyzed DPF was demonstrated with the NTP reactor
u Three-way interaction exists between:– Soot loading– DPF inlet temperature– NO2 concentration
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Conclusions
u NTP Reactor & Power Supply performance is acceptable– Potential to reduce power consumption with short pulse power supply
u NTP assisted catalysis has low NOx performance over transient MVEG emission cycle
– Catalysts tested are too selective for the hydrocarbon species present in the exhaust
– NOx adsorption and desorption is a major challenge– Catalyst durability and performance requires much more development
resources
u NTP has the potential to enable continuous regeneration of a non-catalyzed DPF, given the proper levels of temperature, soot loading, and NO2