Combustion, Aftertreatment and Control Key Elements for Emission Reduction of US HSDI Diesel Engines ERC - 2005 Symposium, Madison Ulrich Pfahl AVL Powertrain Engineering Plymouth, MI, USA ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 1
Content Introduction Combustion Low NOx Strategy Low Load Low NOx Strategy High Load Aftertreatment Control Summary ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 2
LD FTP 75 & US 06 and HD emission limits / certification targets 0,1 TPM - g/kg fuel 0,09 0,08 0,07 0,06 0,05 0,04 0,03 0,02 US 06 0,14 PC SUV Due to high speed & load operation extremely difficult to achieve 0,25 0,4 0,6 gpm Full Size Pick Up FTP PC FTP Mid Size SUV 2007 Full Size Pick Up 2010 Full Size Pick Up US 06 0,01 0 0 1 2 3 4 5 6 NOx - g/kg fuel ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 3
Spec. Power vs. Peak Firing Pressure Speed Range: 3800-4200 rpm / Displacement per Cyl.: 0.4-0.6L Passenger car / LCV / SUV 65 Spec. Power [kw/l] 60 55 50 45 Base Variant Small HSDI =16.5 FIE 1800 bar Piezo Swirl Modulation Small HSDI 17.5 FIE 1600 bar Solenoid 55 48 Swirl fixed 40 35 30 110 120 130 140 150 160 170 180 190 Peak Firing Pressure [bar] ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 4
Compression Ratio Peak Firing Pressure - bar 220 210 200 190 180 170 160 150 140 130 120 110 Baseline ~17,5:1 T Exhaust ~780 C Development trend ~16.5:1 T Exhaust ~820 C 30 35 40 45 50 55 60 65 70 75 80 85 Rated Specific Power - kw/l PFP Reduction 90 ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 5
Combustion Low NOx Strategy Low Load Area ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 6
Area of Alternative Combustion VTG and Standard FIE 16 14 Load bar 12 10 8 6 Optimised Standard Combustion 4 2 Alternative Combustion HCLI, frühe Einspritzung 90196b-03 0 1000 1500 2000 2500 3000 Speed RPM 3500 ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 7
Potential and Challenge of Alternative Combustion Multicylinder engine (~0.5L/Cyl Class); 1500 rpm; 15% load 120 500 % -3% -93% -76% % 100 400 80 60 40 20 0 Conventional Combustion Alternative Combustion BSFC NOx Soot 300 200 100 0 +250% +350% HC CO ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 8
Alternative Combustion Emissions in Urban Cycle Part Multicylinder engine (~0.5L/Cyl Class) with Cylinder pressure guided Closed loop combustion control Conventional Combustion Alternative Combustion NOx Opacity ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 9
Combustion Low NOx Strategy Higher Load Area ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 10
Emission reduction with higher EGR Rates at increased boost pressures 2000 rpm; 45 mm3/stroke;swirl/intake temperature=const; Boost pressure/rail pressure/soi/egr-rate=variable; 0,7 bar 0.7 bar Relative Relative boost boost pressure pressure 1,9 bar 1.9 bar 50 EGR AGR Abgasrückführrate EGR Rate [%] [%] Emissionen Emissions pro Zylinder [g/h] [g/h] 40 30 20 10 Soot RUSS AGR EGR NOX Soot RUSS NOX 0 1,1 1,2 1,3 1,4 1,5 1,6 1,7 Lambda [-] ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 11
NOx, Soot - g/h 14 12 10 8 6 4 2 Effect of part load boosting on EGR, NOx and Soot at const. SCRE* test results NOx Soot EGR 2000rpm; IMEP=8bar; =1,4; Displ 0,533L Swirl / T intake / P rail / SOI Pilot & Main =const 45 40 35 30 25 20 15 EGR - % 0 10 0,4 0,6 0,8 1 1,2 1,4 cylinder Relative Intake Pressure - bar *) SCRE: single cylinder research engine ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 12
Boosting Concepts 2,40 ~2000 RPM, ~50% Load 2,20 2,00 Lambda 1,80 1,60 1,40 Base VTG Small VTG 2-stage TC or VTG with VGC NOx -35% 1,20 1,00 0 5 10 15 20 25 30 35 40 45 EGR-Rate - % ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 13
Boosting helps to improve emissions 12 SCRE* 0,5L/Cyl Class, 2000rpm, IMEP=13 bar, T intake =const 10 Soot - g/kg fuel 8 6 4 Increasing Rail Pressure Increasing EGR-Rate 2 0 0 5 10 15 20 25 30 35 *) SCRE: single cylinder research engine Increasing Boost Pressure NOx - g/kg fuel Basis ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 14
Increase of EGR and Rail pressure RAIL [bar] NOXS [g/kg] 2200 2000 1800 1600 1400 1200 1000 50 40 30 20 10 0 2000rpm - V FUELSTR = 45mm 3 /str Increase of EGR and Railpressure 6-hole Nozzle 1,1 1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0,0 SOOT [g/kg] Lambda [-] EGR [%] 2,8 2,6 2,4 2,2 2,0 1,8 1,6 35 30 25 20 15 10 5 0 201 200 199 198 197 196 195 194 0,9 0,8 0,7 0,6 0,5 0,4 ISFC [g/kwh] HC [g/kg] ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 15
NOx * Smoke 350 300 250 200 150 100 50 0 Efficient EGR cooling improves Emission significantly NOx*Smoke=ppm*BSU ~1000 rpm ~ 2 bar ~1600 rpm ~ 4 bar ~1600 rpm ~ 7 bar 0 50 100 150 200 250 300 350 Exhaust Temperature Drop in EGR Cooler - C ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 16
Aftertreatment ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 17
NOx-Catalysts Conversion efficiency 120 NOx - Conversion - % 100 80 60 40 20 0 FTP 75 Focal Area US 06 Focal Area 100 150 200 250 300 350 400 450 500 550 600 Catalyst Temperature - C NOx - Ads 1 NOx - Ads 2 SCR-Cat 4Way - Cat ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 18
Durability performance of aftertreatment technologies 100 Conversion - % 90 80 70 60 50 40 30 20 10 0 DPF UREA SCR NOx Adsorber 0 30.000 60.000 90.000 120.000 Driving Distance - miles ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 19
Exhaust Aftertreatment for HSDI Diesel DPF (> 90 % < 99%) PM Mass/Number Reduction DPF as must for future NOx Reduction Separator (> 40% < 50%) UREA SCR NOx adsorber NOx application scenario: If > 55 / 60% after 120.000 miles, then SCR. However EPA, Infrastructure and some OEM s reluctance If < 50% after 120.000 miles then NOx-Adsorber. However yet not proven ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 20
The use of EAS and it s type of operation asks for further raw emission reduction NOx increase in % DPF loading time / DPF regeneration time 40 60 80 100 16 14 12 10 8 6 4 2 0 4 to 10% 1 2 3 4 5 6 7 NOx emission during regeneration / standard NOx emission ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 21
Control ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 22
Cylinder Pressure guided EMS Development Environment Calibration PC ETK EMS Start and Duration of Injection (Cyl.1 Cyl.n) (Ethernet) VNT, EGR, Swirl,... EGR-Coolerbypass Actuators ES1000 AFS, RPS, Pedal,... Sensors MFB50% Cyl.1 (CAN) MicroAuto Box Signal- Interface Pressure sensor Charge- Amplifier 60-2 Trigger One Lead-cylinder Example ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 23
Alternative Combustion. In Vehicle Noise Assessment on Acoustic Chassis Dyno Multicylinder engine (~0.5L/Cyl Class) with Cylinder pressure guided Closed loop combustion control 70 km/h Engine Speed - rpm 100 km/h 120 km/h Time - sec Conventional Combustion Alternative Combustion Sound Pressure - dba Time - sec Sound Pressure - dba 1 khz Frequency - Hz ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 24
Benefits of Closed Loop Combustion Control Stability over Lifetime (Tolerances, Emissions) Other sensors can be simplified or even deleted Reduced Application effort Enabling highest Power-density (PFP Monitoring) OBD Compensation of Fuel quality influence Torque feedback and control Improved cold-startability and engine warm-up (Monitoring) Enabling new combustion concepts ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 25
Summary ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 26
Conclusions For passenger cars the main challenge will be the US06 driving cycle with the high load areas. For heavier SUVs the lower loaded FTP75 will be the main focus, since heavier SUVs have higher NOx limitations in the US06 cycle, while the values for the FTP75 are the same as for PC. Main Fields of Combustion Development: Combustion (Conventional, Alternative) - Charge Management (Boosting, EGR, Charge/EGR Cooling) - Injection (Pressure, Nozzle, Architecture) Control (Model based, Cylinder / Combustion guided, Multivariable Controller, Tolerances, Long Term Stability) DPF will be mandatory. Necessity and definition of NOx aftertreatment dependents on engine / vehicle combination. ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 27
Thank you for your attention! ERC - 2005 SYMPOSIUM June 8 th, 2005 Page - 28