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Experience with SCR Technology for DieselExhaust Emission Control of Trucks in Asia,
Europe and North America
Gary Keefe and Raimund Mueller
Bangkok, February 1, 2001
Motivation for Diesel Engine Emission Control
Human health impact
Photochemical smog Acid rain Human health impact
Human health impact
Greenhouse gas - climate change
Photochemical smog
EngineEmissions
HC
NOx
PM
CO
CO2
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Why Reducing Nitrogen Oxides?
Nitrogen Dioxide (NO2)
from the Exhaust Gas
Ozone forms and is inhaled by persons
Sun effect
Nitrogen Monoxide
(NO)
Atomic Oxigen (O)
Molecular Oxigen (O2)
SCR Reactions with Reducing Agent -Urea
Hydrolysis-Reaction: (NH2) 2CO + H2O 2 NH3 + CO2
SCR-Reaction:
4 NH3 + 4 NO + O2 4 N2 + 6 H2O
8 NH3 + 6 NO2 7 N2 + 12 H2O
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Applications of SINOx Catalysts and Systems
Power Plant Truck
Greenhouse Fertilizer/CoGen
Incinerator
Marine Propulsion
Railroad Engine
Diesel Car
Stationary Diesel
SINOx -Catalysts
Future Emission Standards for Commercial Vehicles
and Market Requirements
Source: Moser et. al.NOx - g/kWh
0190
200
210
220
230
1 2 3 4 5 6 7
Marketrequirement
Legislative
requirement(NOx)
Trade -off with currenttechnology (EU3/US 98)
B S F C
- g / k W h
0
0,1
0,2
0,3
0,4
P a r
t i c u
l a t e s -
g / k W h
2007
2004/2005
2008
1998/2000EUUSJ
Worldwide exhaust emission standards for HD diesel engines beyond 2000
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Exhaust Emission Control Motivation: Diesel Trade-Off
NOx-Emissions [g/kWh]
98632100
1074 5
0,04
0,06
0,08
0,10,12
0,14
0,16
0,18
P M
- E m
i s s i o n s
[ g / k W h ]
0,02
NOx/PMDPF
EGR &Combustion
SINOx
E n g i n e ( P M - o p t )
NOx/BE
S p e c i
f i c
F u e l
C o n s u m p
t i o n
[ g / k W h ]
Emissions-Reduction Potential with SINOx System
Increase of engine-out NOxemission due tofuel efficienttuning, for lowPM emission
Improvement of
BSFC over EURO 3 engineattainable
Emission data in g/kWh
BSFC0
2040
60
80
100
120
140
160
180
200
NOx HC PM
R e l a t
i v e
E m
i s s i o n
i n %
E
5
9
1,8
0,660,6
0,12
0,1
0,03
0,02
80% NOx-reduction
80% HC-reduction
30% PM-reduction
SINOx Capability EURO 3 EnginePM & BSFC optimi zed engineOptimized engine w/ SINOx
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The SINOx System for Trucks
Urea Dosing Unit,Urea and Diesel tankintegrated in one unit
SCR-catalyst integratedin series silencer
base-metal catalyst ceramic monolith cat.volume 30 ltr.
200 cpsi
12 l HD-Diesel engines 6-cylinder 400 hp class
diagnosis
SCR-Catalyst
NOx,O2
reducingagent
(NH2) 2CO
purifiedexhaust
N2,H2O
Urea-DosingUnit
exhaust
operatingdata
(NH2) 2COEDC
ECU DCU
engine
Characteristics of SINOx SCR Systems
Active emission control system integrated solution - Not just an Add-on communication between engine and urea dosing unit via CAN bus integration into the vehicle infrastructure (pressurized air, electrics)
Resources Diesel fuel with S < 0,15% 32,5% solution of urea as reducing agent
Temperature range of exhaust: gas 200...550C (without oxidation catalyst) no or slight increase of exhaust backpressure compared to standard silencer combination with particulate filter feasible if desired for special applications
Function
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Urea distribution infrastructure concept Industry Committee established with members including oilindustry, vehicle and engine manufacturers ureamanufacturers and Siemens:
Step 1- Refilling urea at truck home yard
Step 2 - Refilling urea at main truck stops locatedalong the major highways
Step 3 - Refilling urea at the gas stations Urea Pump Station
Urea Charateristics: non-hazardous, non-explosive, non-toxic released as a food-additive lowest water polluting classification
Reducing Agent Aqueous Urea
Urea - Applications
UREA
Agriculturefertilizer feed
Water industrynutritive substance for the biologicaltreatment of wastewater
Power industry
reducing agentfor exhaust gas
Chemical Industryraw material for:
UF-resinsUrethanesand many others Food processing
for chewing gumproduction
Medical andpharmaceutics for theproduction of:
barbituratesdiureticsspecial injury bandages
Other industriesauxiliaries in:
chipboard industrytextile industrycoolant lindustrycosmetics industry
There is no shortageof urea
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SINOx System - Field Demonstration
Total mileage: 21 trucks 6.099.000 kmMax. mileage of single vehicles: 524.000 km
(Status: 2000-03-27*)
*) 2nd roadtest finished1999-12-31. Some vehiclesareoperatedfurtherfor longtermtesting
Measurements
Investigations:
on the road (vehicle): NOx-reductionUrea consumptionmechanical durability
in lab reactor (SCR-catalyst): activity (NOx-reduction) = f (mileage)physico-chemical measurements(surface area, composition, etc.)
on the test bench (silencer): NOx-reduction at start (ESC, ETC)NOx-reduction at end (ESC, ETC)
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0
0,004
0,008
0,012
0,016
0,02
P M [ g / k W h ]
total PM soluable insoluable0
0,004
0,008
0,012
0,016
0,02
P M [ g / k W h ]
total PM soluable insoluable
PM and NOx emissions - ESC test w/12 ltr. HDE +
SINOx
0
2
4
6
8
10
12
N O x
[ g / k W h ]
NOx
Engine out emissions after SINOxEngine out emissions after SINOx
- 81%
PM and NOx Emissions - ETC test w/12 ltr. HDE+SINOx
0
0,0040,008
0,012
0,016
0,020,024
P M [ g / k W h ]
total PM soluable insoluable0
24
6
8
10
12
N O x
[ g / k W h ]
NOx
Engine out emissions after SINOx
0
0,0040,008
0,012
0,016
0,020,024
P M [ g / k W h ]
total PM soluable insoluable
- 86%
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On-board NOx-measurement on mixed highway
Time in seconds
Highway Section Bamberg Redwitz
N O x -
C o n c e n
t r a t
i o n
i n p p m
0200
400600800
100012001400160018002000
0 750 1500 2250 3000
NOx conversion: 71.2 %NOx conversion: 71.2 % NOx before Cat.
NOx after Cat.
NOx before Cat.
NOx after Cat.
Results of Measurements
Measurements were done and reported by TV Automotive, Germany
1st demonstration program: 0 km 130,000 km remark
NOx reduction on-road: 56% 54% constant within accurarcy
Urea consumption fleet average 4.1 % of diesel fuel consumption
2nd demonstration program: 0 km 272,000 km remark
NOx reduction ESC cycle: 65% 63% constant within accurarcy
NOx reduction ETC cycle: 70% 71% constant within accurarcy
NOx reduction on-road: 74% measured after 212,000 km
Urea consumption fleet average 5.5 % of diesel fuel consumption
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Catalyst activity during field demonstration
Catalyst Activity in accordance with predicted deterioration factor (over 500,000 km)Catalyst total specific surface area and active materials constant over test program Deposition of phoshate on catalyst surface in upstream face of catalyst
0 .6
0 .7
0 .8
0 .9
1
0 1 0 0 20 0 3 0 0 4 0 0 5 0 0 6 0 0
Driv ing Performance [1000 km]
N O x
C o n v e r s
i o n
P e r f .
( r e
l . )
SINOx Catalyst
Fuel optimized engine meeting EURO 4/2 with SCR
Engine modification to EURO III engine for best fuel economy (BSFC)
NOx & PM Emission below EURO 4/2 in ESC and ETC
Program by VROM, AVL, Deutz, Siemens(Source: AVL, Cartellieri et. al. )
0,0
2,0
4,0
6,0
8,0
10,0
12,0
Baseline Optimized w /SCR EUROIV/1
w/SCR EUROIV/2
N O x , P M * 1 0 0 i n
180
185
190
195
200
205
210
215
220
225
B S F C i n g
NOx
PM * 100
BSFC
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US truck SCR investigatio
