THE IMPACT OF BIODIESEL FUEL BLENDS ON AFTERTREATMENT DEVICE PERFORMANCE IN LIGHT-DUTY VEHICLES Matthew Thornton NREL, Marek Tatur and Dean Tomazic FEV Engine Technology Inc. National Biodiesel Conference & Expo 2008 February 5 th 2008
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Project Overview One of several projects evaluating biodiesel future engine and emission control systems Collaboration between the National Biodiesel Board (NBB) and NREL (DOE) under a cooperative research and development agreement (CRADA) Evaluate the impact of biodiesel fuel blends on emission control system performance Includes two emission control systems and two fuel blends on a light-duty platform NAC/DPF and SCR/DPF systems 5% and 20 % biodiesel blends Optimization and performance over time CFD Modeling of SCR Engine teardown, oil dilution analysis, catalyst analysis Project duration approximately 2+ years
Fuel Comparison ULSD Base Fuel B20 Density (kg/dm 3 ) Cetane Number Carbon (wt%) Oxygen (wt%) Hydrogen (wt%) Kinematic Viscosity at 40 C [mm 2 /sec] 0.846 42.0 87.08 0.00 12.92 2.28 0.853 43.2 85.04 2.37 12.59 2.74
Hardware Overview SCR System
Hardware Overview NOx Adsorber System
Test Cell Set-up NOx Adsorber System DOC/NAC Engine Out Dual wall pipe DPF
Hardware Overview Test Vehicle Hardware
Hardware Overview Test Engine Hardware Power [kw] BMEP [bar] 120 110 100 90 80 70 60 50 40 30 20 10 400 350 300 250 200 150 22 100 20 18 16 14 12 10 8 6 4 3.5 3.0 2.5 2.0 1.5 1.0 0.5 500 1000 1500 2000 2500 3000 3500 4000 4500 0.0 5000 Speed [rpm] Torque [Nm] Smoke [FSN] Engine Power Peak torque Max engine speed Max. BMEP Number & Arrangement of Cylinders 113 kw @ 4000 rpm 360 Nm @ 2000 rpm 4700 rpm 21 bar 4 cylinder inline Firing order 1-3 - 4-2 Valve train Displacement 4 Valve DOHC 2.15 L Bore to stroke ratio 1.0034 Compression Ratio 18 Fuel injection system 2nd Generation Common- Rail DI
Engine-out Emission Optimization Base Euro 4 Calibration NEDC > 0.25 g/km NOx (0.4 g/mi) FTP75 < 0.7 g/mi NOx Replacement of stock ECU with development unit including RP capabilities Access to all engine/combustion parameters: Begin of injection, Pilot + Post injections, Railpressure, Boost pressure, EGR, Throttle, Swirl Steady-state optimization in 14 operating points Average reduction of all emissions over 50% Transient optimization in test cell and vehicle Average reduction of all emissions over 50% Implementation of emission control devices
Engine-out Emission Optimization 800 700 600 Base calibration Optimized calibration NOx emissions comparison in 14 calibration modes 500 NOx [ppm] 400 300 200 100 0 650 0.00 1000 1.80 1200 3.02 1425 1.61 1615 3.07 1750 6.30 2000 4.00 2060 6.40 2300 4.05 2050 1.46 2250 8.16 2650 6.69 1450 4.59 1750 4.59 Engine speed [rpm] / BMEP [bar]
Engine-out Emission Optimization Smoke emissions in 14 calibration modes 6 5 Base calibration Optimized calibration 4 Smoke [FSN] 3 2 1 0 650 0.00 1000 1.80 1200 3.02 1425 1.61 1615 3.07 1750 6.30 2000 4.00 2060 6.40 2300 4.05 2050 1.46 2250 8.16 2650 6.69 1450 4.59 1750 4.59 Engine speed [rpm] / BMEP [bar]
Emissions Results NAC System
NMHC [g/mile] PM [mg/mile] Test Results Vehicle Emission 11 10 9 8 7 6 5 4 3 2 1 0 Tests (at the U.S. EPA) Cold LA4 Hot LA4 Composite FTP 75 50,000 mile 120,000 mile 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 NOx [g/mile] 0.100 0.075 0.050 0.025 50,000 mile 120,000 mile 0.000 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 CO [g/mile]
NMHC [g/mile] PM [mg/mile] Test Results Vehicle Emission 11 10 9 8 7 6 5 4 3 2 1 0 Tests (at the U.S. EPA) Composite ULSD Composite B20 Composite B5 50,000 mile 120,000 mile 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 NOx [g/mile] 0.100 0.075 0.050 0.025 50,000 mile 120,000 mile 0.000 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 CO [g/mile]
Test Results Vehicle Emission Tests (at the U.S. EPA) B20 = 11% ULSD = 10% B20 = 46% ULSD = 45% B20 = 43% ULSD = 45% Temperature [ C] Vehicle Speed [mph] 60 50 40 30 20 10 0 500 450 400 350 300 250 200 150 100 50 0 Engine Out - B20 Tail Pipe Out - B20 Engine Out - ULSD Tail Pipe - ULSD B20 - Temperature upstream LNT ULSD - Temperature upstream LNT 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 Time [s] 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 Accumulated NOx [g]
Test Results Durability Testing Durability Cycle 700 Duration Duration completed 750 = 107% Number of Desulfurization completed Number of DPF regeneration completed 0 100 200 300 400 500 600 700 Time [hr] 28 311 0 50 100 150 200 250 300 350 DeSOx Avg Temp in DPF [deg C] DeSOx Avg Temp in NAC [deg C] DPF Regen Avg Temp in DPF [deg C] DPF Regen Avg Temp in NAC [deg C] OP2 Avg Temp in DPF [deg C] OP2 Avg Temp in NAC [deg C] OP1 Avg Temp in DPF [deg C] OP1 Avg Temp in NAC [deg C] 460 471 468 503 625 651 612 628 0 100 200 300 400 500 600 700 800 Temperature [deg C]
NMHC [g/mile] PM [mg/mile] 12.00 10.00 8.00 6.00 4.00 2.00 Test Results Durability Testing 0 hr - FTP 75 composite Intermediate life - FTP 75 composite Full usefull life - FTP 75 composite 50,000 mile 120,000 mile 0.00 0.000 0.010 0.020 0.030 0.040 0.050 0.060 0.070 0.080 NOx [g/mile] 0.100 0.075 0.050 0.025 50,000 mile 120,000 mile 0.000 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 CO [g/mile]
NMHC [%] NMHC [%] 102 100 Test Results Durability 98 96 94 102 100 98 96 94 92 90 Testing Conversion Efficiency [%] 50 60 70 80 90 100 NOx [%] Conversion efficiency target 120,000; 50,000 miles 0 hr FTP composite Intermediate life FTP composite 50 60 70 80 90 100 CO [%]
Test Results Fuel Economy Impact Vehicle (FTP75) NOx [g/mile] 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.74 0.72 0.34 0.31 0.05 0.03 B20 ULSD 35.3 34.8 31.8 30.7 30.7 30.1 40.0 35.0 30.0 25.0 20.0 15.0 10.0 5.0 Fuel Economy [mpg] 0.0 Base EURO 4 T2B5 Feedgas T2B5 Tailpipe Base EURO 4 T2B5 Feedgas T2B5 Tailpipe 0.0
Test Results Fuel Economy Impact Vehicle (FTP75) B20 ULSD 35.3 34.8 37 36 35 31.8 30.7 30.7 30.1 34 33 32 31 30 29 28 Fuel Economy [mpg] 27 26 Base EURO 4 T2B5 Feedgas T2B5 Tailpipe 25
Summary and Conclusions Vehicle as well as test cell results indicate an increase in engine out NOx and decrease in PM using Biodiesel blends Tail pipe NOx emissions decreed using Biodiesel blends (for the NAC system which was calibrated for B20 operation) This NAC system achieved Tier 2 Bin 5 emission levels at simulated full useful life (120k mi) NOx adsorber regeneration control remains the same between petroleum based and Biodiesel blended fuel. Fuel economy impact using Biodiesel fuel was marginal using an integrated Tier 2 Bin 5 system. Durability investigations focusing on Biodiesel effects on engine and aftertreatment system are currently underway for the SCR system.
Acknowledgments DOE Office of FreedomCAR and Vehicle Technologies, Advance Petroleum Based and Non-Petroleum Based Fuels Activities: Stephen Goguen, Kevin Stork, and Dennis Smith, Technology Managers National Biodiesel Board: Steve Howell MECA: Joe Kubsh and Rasto Brezny EPA: Charles Schenk