Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting Tier II Bin 5

Transcription

1 1 Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting Tier II Bin 5 DOE and Ford Motor Company Advanced CIDI Emission Control System Development Program (DE-FC26-01NT41103) Diesel Engine Emission Reduction Conference August 2003

2 2 Presentation Overview DOE Program Overview Vehicle Results SCR Functional Improvements Exhaust Gas Sensor Development CDPF Strategy Development Urea Program Future Work

3 3 Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting Tier II Bin 5 Program Overview

4 DOE Ultra-Clean Fuels Program Outline of Ford s program to achieve Tier II emission standards for 2007 using low sulfur diesel fuel as an enabler for a high efficiency aftertreatment system. 4 Primary Contractor Subcontractors Catalyst Suppliers Phase I - Initial build/test phase (12 mos.) Establish baseline emission control system Deliver engine dynamometer NOx and PM test results Demonstrate and deliver prototype vehicle NOx and PM test results Deliver urea delivery (infrastructure) prototype Phase II - System/component optimization phase (18 mos.) Define final system hardware components Deliver NOx and PM performance data Demonstrate emission control system (includes NOx and PM data) Phase III - Durability/Demonstration phase (18 mos.) Definition of durability test procedure Final NOx and PM emission levels Define fuel sulfur limits for emission control system Final report for the completed program

5 5 FEV Program Concept Design CFD Modeling including urea injection Engine Dynamometer Baseline and rapid warm-up testing Urea SCR/CDPF optimization Transient FTP/US06 testing Emission Control System Durability 5000 hours (~120k miles)

6 ExxonMobil Program Intellectual property discussion delayed program for 9 months; program was then accelerated to contain original objectives. SCR urea catalyst development Durable, high NOx conversion from 150 to 600 C with low N 2 O make. Urea program Co-fueling concept Low temperature urea solution Infrastructure studies Fuel development Make and use fuel, which will be typical of 2007 production with 15 ppm sulfur cap. 6

7 7 Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting Tier II Bin 5 Vehicle Results

8 8 LDT Exhaust System Turbo DOC Spray Deflector NOx sensor DOC SCR Catalyst aqueous urea Flow mixing plate

9 Diesel Fuel Properties ExxonMobil blended 14,000 gallon batch to represent typical 2007 ULSD. Uniform fuel over program duration. Stored and dispatched in drums. 9 Estimated Proposed Program Proposed 06 Diesel DOE Program Fuel 2007 Fuel Property Properties Min/Max Delivered Cert. Fuel Sulfur, ppm 15* 10 / / 15 Density, kg/m / / 865 Aromatics, vol. % / min Polyaromatics, wt. % 10 6 / no spec Cetane number / / 50 T50, C / / 282 T90, C / / 332 * As delivered to the vehicle

10 400 LDT Temperatures and Space Velocity FTP-75 Test Temperature ( C) Space Velocity (hr -1 ) urea on Time (seconds) Turbo Out DOC in SCR in SCR out Space Velocity 0

11 Weighted FTP-75 Emissions Bag 3 emissions 0.42 Bag 2 emissions (82%) 0.20 Bag 1 emissions Tier II Bin 5 Stds, 120k mi ( ) Catalyst efficiency (79%) grams/mile (82%) (94%) (93%) (96%) (97%) (52%) (52%) (82%) THC NMHC CO/10 NOx

12 12 Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting Tier II Bin 5 SCR Functional Improvements

13 Importance of NO 2 /NOx Ratio on Degreened Catalyst Performance 13 NOx Conversion (%) NO only 1:1 NO:NO Catalyst Temperature ( C)

14 Importance of NO 2 /NOx Ratio on Aged 14 Catalyst Performance NOx Conversion (%) HT aged, NO only HT aged, 1:1 NO:NO2 sulfated, NO only sulfated, 1:1 NO:NO Catalyst Temperature ( C)

15 Impact of Sulfur and Regeneration on SCR Performance NOx conversion (%) degreened 120k mi sulfated 10 after regen at 650 C Catalyst Temperature ( C)

16 Impact of HC on SCR performance NOx Conversion (%) Degreened Activity (250 C, 20% NO 2 in feed) Start HC Addition End HC Addition 500 C, 10 min Activity Regained % NOx Conv. Cum. HC's Cumulative HCs (g/l catalyst)

17 NOx Conversion [%] 100 Importance of Urea Mixing (Steady-State Engine Dyno Results) System target 25 A mm conv System target 150 B mm conv System mesh downstream C conv System mesh upstream D conv System target 25 A mm slip slip System target 150 B mm slip slip System mesh downstream C slip slip System mesh upstream D slip slip NH3 Slip / Engine Out NOx [%] NH3 / NOx Ratio [molar]

18 100 Importance of Urea Mixing (Transient Vehicle Results) 18 Cumulative TP NOx (% EO NOx) Poor mixing Improved mixing test time (s)

19 30 Importance of Rapid Warmup 19 Cumulative TP NOx (% EO NOx) Model Model w/rapid warmup test time (s)

20 20 Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting Tier II Bin 5 Exhaust Gas Sensor Development

21 NOx sensor (NGK): Laboratory data: (~1cm DIA tube) 600 Vehicle data: V ppm NO ppm NH ppm NO baseline C 3 H 6 (ppm) ppm _06_03: 112:bags1_2 NO (FTIR) NO 2 (FTIR) NH 3 (FTIR) Sensor (ppm_no) time (sec)) S(NO) > S(NH 3 ) > S(NO 2 ) sensitivity For this test, the sensor was located downstream of SCR catalyst. As expected, the sensor responded to both NO and NH 3. Also, the tailpipe NOx was all NO.

22 NH 3 Sensor: Prototype sensors are under development by automotive suppliers. Vehicle data from one such sensor shown below (composition proprietary) : Selective NH 3 response. Some sensitivity to H 2 O. 22 Vehicle test: Comparison of NH 3 measured at the tailpipe using FTIR with that predicted by the sensor (after compensating for water) ppm _03_03: 561:bags1_2 FTIR sensor time (sec))

23 23 Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting Tier II Bin 5 CDPF Strategy Development

24 24 Future LDT Exhaust System Turbo DOC Spray Deflector NOx sensor DOC SCR Catalyst CDPF aqueous urea Flow mixing plate

25 Temperatures during DPF Regeneration 25 Exhaust Temperature [ C] Fuel Flow Time [min] TBDPF TDPF6 TDPF1 TDPF7 TDPF2 TDPF8 TDPF3 TDPF9 TDPF4 TADPF TDPF Fuel Flow [kg/h] dia x 10 L (229 x 254 mm) 7 L from rear of filter grid T# (mm) type complete complete 3 50 complete cent. side cent. side 6 50 cent. side corner corner 9 50 corner 4

26 Temperatures during DPF Regeneration 26 Exhaust Temperature [ C] T_BDPF T_DPF1 T_DPF2 T_DPF3 T_DPF4 T_DPF5 T_DPF6 T_DPF7 T_DPF8 T_DPF9 T_ADPF Fuel Flow Time [min] Fuel Flow [kg/h] dia x 10 L (229 x 254 mm) 7 L from rear of filter grid T# (mm) type complete complete 3 50 complete cent. side cent. side 6 50 cent. side corner corner 9 50 corner 4

27 27 Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting Tier II Bin 5 Urea Program

28 28 Urea Program Prototype Urea Co-fueling System Status Co-axial nozzle design chosen and improved for durability and reliability. Urea pumping unit designed and feasible for modern dispenser. Prototype system being built to evaluate co-fueling, including low temp. Vehicle modified with compatible fillneck and urea storage for demo.

29 29 Urea Program Low Temperature Urea Solution Use of aqueous urea can cause difficulty in cold climates. Urea at 32.5 wt% has the lowest freeze point at 12 F(-11 C) of any blend in water. Potential freeze point depressants investigated, but found to cause negative catalyst impact at Ford. Conclusion: Heated systems will be needed for colder climates.

30 30 Urea Program Study of Urea Supply Scenario Meeting with key urea suppliers to understand supply chain from production to service station. Using A. D. Little Study as baseline. Determining optimum supply case. - forecast urea volumes - estimate urea cost per gallon

31 31 Urea SCR and DPF System for Diesel Sport Utility Vehicle Meeting Tier II Bin 5 Future Work

32 32 Future Work Rapid warm-up strategy Choose final catalyst formulations/configuration Aging cycle development 5000 hrs Sensor development Continue urea infrastructure investigation

33 33 Acknowledgements Ford Brendan Carberry, Dick Chase, Bob Hammerle, Dave Kubinski, Paul Laing, Christine Lambert, Mike Levin, Cliff Montreuil, Rick Soltis, Devesh Upadhyay, Michiel van Nieuwstadt, Scott Williams FEV Erik Koehler, Dean Tomazic Exxon Mobil Joan Axelrod, Jeff Beck, Bill Blazowski, Owen Feeley, Rich Grosser, Mike Kerby, Marcus Moore, Mike Noorman, Charlie Schleyer