Achates Magnum OP Engine Low NO X Engine-Aftertreatment System

Transcription

1 Achates Magnum OP Engine Low NO X Engine-Aftertreatment System ASME Fall ICE Achates OP Engine Symposium November 7, 2018 Christopher Sharp - SwRI Samrat Patil, Ahmad Ghazi, Fabien Redon, John Headly - Achates Power Advance Science. Applied Technology

2 Motivation Ozone nonattainment areas across the United States continue to grow Growth in population Continued tightening of ozone standard 2015 EPA rulemaking changed NAAQS for ozone to 70 ppb CARB Inventory shows on-road heavy-duty trucks are ~20% of all NO X emissions California requires more reduction in NO X emissions to meet the current NAAQS for ozone and PM The current 0.20 g/bhp-hr NO X standard isn t enough 2

3 Comparing 0.2g/hp-hr and 0.02 g/hp-hr ~0.06 g/hp-hr ~0.01 g/hp-hr Cold-FTP SAE Hot-FTP Aftertreatment NO X Conversion Efficiency, % Test Config FTP Transient Cold Hot Composite RMC-SET WHTC Baseline 75% 98.5% 95% 97% 97% Low NO X 98% 99.7% 99.5% 99.3% 99.4% Assumes ~ 3 g/hp-hr Engine-Out NO X 3

4 Final Stage 1 ARB Low NO X Configuration NO X Levels with Development Aged Parts, g/hp-hr Cold-FTP Hot-FTP Composite RMC-SET Engine-Out Tailpipe Volvo MD13TC Euro VI All catalysts are coated on 13 diameter substrates SCRF is 13 X 12 on high porosity filter substrate Remaining catalysts are 13 X 6 on thin wall, low thermal mass substrates All sensors shown are production-type 4

5 Questions from Stage 1 Demonstration With a more favorable engine platform, is a less complicated aftertreatment system possible? Primary goal = removal of supplemental heat With a more favorable engine platform, can the GHG impact be reduced or eliminated? Achates Magnum OP engine platform provides potential to address both of these concerns... 5

6 Current Achates OP Engine Test Platform Displacement 4.9L Arrangement Bore Total Stroke Inline 3-cyl OP 98.4 mm mm Stroke-to-Bore Ratio 2.2 Compression Ratio 15.4 : 1 Nominal Power (kw@ rpm) Max. Torque (Nm@rpm) Engine mode investigations on 4.9L 3-cyl OP engine platform Results scaled to planned 10.6L 3-cyl platform size for AT system simulations and planning 6

7 Achates OP Engine Catalyst Light-Off Mode OP Engine has greater flexibility to modify scavenging and trapped residuals while maintaining stable combustion Enables CLO mode to target very high exhaust enthalpy and low engine-out NO X Fuel economy advantage compromised for a limited time period released to normal mode after ~ 400 seconds overall cold-ftp BSFC still < conventional engine 7

8 Exhaust Temperature, degc Achates Magnum OP Engine Cold-Start FTP Exhaust Temperatures Achates OPS ARB Low NOx - Baseline CLO Mode ARB Low NOx - Final Normal Mode >200 C at 37 seconds Time, sec SAE

9 Achates Magnum OP Engine Cold-Start FTP Engine-Out NO X < 0.04 g/hp-hr before LO-SCR light-off SAE

10 LO- SCR DOC SCR SCR ASC Planned Magnum OP Engine Low NO X AT System = NO X Sensor = DEF Dosing = NH 3 Sensor = NH 3 Dosing = Temp Sensor Close-Coupled Unit (under-hood) Downstream Unit (under-floor) 13x6 13x5 13x8 13x4.5 13x4.5 CSF 13x4.5 Gaseous Mixer DEF Mixer Primary approach to Low NO X = close-coupled light-off SCR (LO- SCR) Requires dual dosing Gaseous NH 3 (ASDS) used upstream for demonstration program 10

11 LO- SCR DOC SCR ASC LO- SCR SCR SCR ASC Alternate AT System Choices Reduced thermal inertia zoned CSF instead of DOC/DPF Zoned- CSF Gaseous Mixer DEF Mixer Higher deno X performance SCRoF instead of DPF (if needed) SCRoF Gaseous Mixer DEF Mixer 11

12 Simulation Results * * Simulation results indicate potential to reach Low NO X Basic dosing strategy used for initial simulations * Improved dosing strategy for hot-start FTP should result in hot- FTP ~ 0.01g/hp-hr This will bring composite FTP < 0.02 g/hp-hr Engine mode test results indicate improved BSFC compared to conventional diesel platform 12

13 Advanced Model-Based SCR Controller with Mid-Bed NH 3 Sensor Feedback T In ṁ exh SCR Model Cell Thermal Model T In ṁ exh SCR Model Cell Thermal Model T In ṁ exh SCR Model Cell Thermal Model T In ṁ exh NO X T wall NO X T wall NO X T wall NO X NH 3 NO 2 / NO X Kinetic Model NH 3 NO 2 / NO X Kinetic Model NH 3 NO 2 / NO X Kinetic Model NH 3 NO 2 / NO X θ 1 θ 2 θ 3 Primary controls challenge is repeatable hot-start/warmed-up NO X < 0.01 g/hp-hr Separate coverage observer models for downstream SCR bricks (7 cells each) LO-SCR will use same approach but without NH 3 sensor feedback Primary calibration parameters are controller gains and coverage targets

14 Magnum OP Engine cclo-scr Package 13in X 6in LO-SCR Magnum OP engine profile allows for easier packaging of closecoupled LO-SCR package 14

15 Magnum OP Engine cclo-scr Package 15

16 Demonstration Vehicle Plans Achates Magnum OP Engine with Low NO X Aftertreatment system will be operating in demonstration vehicles in Southern California by end of 2019 Timeline Aftertreatment Controls for integration in Q Engine Dynamometer integration and calibration Q2/Q Vehicle integration Q