Real-Time Particulate Filter Soot and Ash Measurements via Radio Frequency Sensing

Transcription

1 Real-Time Particulate Filter Soot and Ash Measurements via Radio Frequency Sensing 19 th ETH Conference on Combustion Generated Nanoparticles Zurich, Switzerland June 29, 215 Alexander Sappok, Paul Ragaller, Leslie Bromberg 1

2 Challenge: Determination of Filter/Catalyst State 2 1 Stanton, D., "Systematic Development of Highly Efficient and Clean Engines to Meet Future Commercial Vehicle Greenhouse Gas Regulations," SAE Int. J. Engines 6(3): , 213 2

3 RF Sensors for Direct Measurement of DPF Loading Antenna (RF Probe), similar size to exhaust temperature sensor Stainless steel rod-type antenna (passive component) RF Control Unit DPF Loading 1. Amount 2. Type (PM vs. Ash) 3. Distribution Signal fullycontained in DPF housing Single or dual RF Antenna Fast response < 1 second DPF RF sensor responds to changes in DPF dielectric properties 3

4 RF System Measurement Methodology S12 Transmission Mode 1 Mode 2 Increasing Filter Contaminant Levels Antennas Mode 3 Mode 4 Mode 5 Filter Example: Two-antenna measurement system Frequency * Adam, Stephen, F., Microwave Theory and Applications, Prentice Hall, Inc., Engelwood Cliffs, New Jersey,

5 Single Probe RF Sensor Integration for DPF Control Hardware and System Setup MY 213 DD-13 diesel engine Stock controls and aftertreatment Open ECU M461 for RF-based control of regeneration HC dosing system upstream of DPF Single antenna RF sensor SAE

6 Single Probe RF Sensor Integration for DPF Control Stock aftertreatment system with 22.3 L DPF (27.73 kg base weight) DOC upstream of DPF (same can) and RF antenna mounted at DPF outlet Aftertreatment Loading Sample Set: 24 cycles PM Load Range: 6 g 126 g Regen Sample Set: 15 DPF cycles PM Load Range: 1 g 18 g +.68 g/l +.45 g/l DPF and SCR RF sensor validation over multiple loading and regeneration cycles Comparison with gravimetric, AVL MSS, BG3, and smoke meter measurements SAE

7 RF-Based Regeneration Management Regeneration Duration Test Procedure DPF loaded to three different levels of PM - High, medium, low load Stock ECU controlled regenerations carried out RF-controlled regenerations repeated at similar conditions Duration normalized to account for small differences in PM load and temperature Reduction in regeneration duration 15% - 3% relative to stock ECU control RF system directly monitors PM levels in DPF during regeneration and terminates HC dosing once oxidation is complete (vs. time-based ECU approach) SAE

8 RF System Transient Response Evaluation DPF DOC AVL GM 1.9L Engine Dynamometer Testing Testing on 1.9L GM turbo diesel engine Transient mode evaluation of RF response AVL MSS and TEOM measurements for comparison with RF and gravimetric PM RF Control Unit EGR Turbo DPF ΔP, T DPF: Cordierite, Catalyzed D 5.66 x 6 (2.47 L) DOC - AVL MSS - TEOM TEOM 8

9 Transient Response Well-Correlated with AVL MSS RF Sg Signal a ([RAW] ) EGR steps result in variation in engine-out PM measured by RF sensor MAF [kg/hr] RF AVL MSS Intergal TEOM RF Differential 5 12 AVL AVL MSS DPF DOC 1 11:54 11:57 12: 12:2 12:5 12:8 12:11 12:14 12:17 12: :54 11:57 12: 12:3 12:6 12:9 Time [hh:mm] RF slope change due to EGR steps 1 MAF (EGR) Torque RF Parameter Rate 6 11:54 11:57 12: 12:2 12:5 12:8 12:11 12:14 12:17 12:2 5 Time [hh:mm] RF AVL MSS TEOM PM [μg], AVL PM (integrated, mg) Torque [ft-lb] Testing on 1.9L GM turbo-diesel at ORNL Catalyzed cordierite DPF GM 1.9L 1 Hz sampling rate for AVL MSS and TEOM Soot [mg/m^3] 2.5 Hz sampling rate for RF sensor 9

10 Transient Response Details of Throttle Tip-In Events RF (Derivative) Throttle [%] RF Signal [Raw] Derivative of RF signal compared to AVL MSS for throttle tip-in events RF AVL RF AVL TEOM Throttle Position Torque Raw RF signal vs. TEOM and AVL (Integrated) 11:38 11:41 11:44 11:47 11:49 11:52 Time [hh:mm] AVL MSS [mg/m^3] Torque [ft-lb] TEOM [μg], AVL (Integrated, mg) 1

11 Frequency Shift Well-Correlated to DPF Ash Levels Pressure Drop Delta_P [kpa] Images: SAE R 2 =.984 Frequency Shift [MHz] Ash Level [g/l] Δf ~ 2 MHz with 6 g/l of ash 4 2 R 2 =.98 Δf Ash Load [g/l] Ash loading level equivalent to ~ 38, miles of on-road accumulation Frequency shift at resonance well-correlated to ash level in DPF 11

12 DPF Soot Load Measurements with Ash RF Soot [g/l], ΔP Soot [g/l] ΔP PM Load [g/l] g RF 3 g/l PM Comparison Ash Load [g/l] 4g dp 3g Gravimteric Soot [g/l] RF and dp (ΔP) measurements both scaled to g/l ash case to develop simple calibration function 2g +.5 g/l RF_Ash g RF_Ash 1g RF_Ash 2g RF_Ash 3g RF_Ash 4g RF_Ash 5g 1:1 dp_ash g dp_ash 1g dp_ash 2g dp_ash 3g dp_ash 4g dp_ash 5g +.5 g/l -.5 g/l ΔP regeneration frequency increases with ash (over-estimate PM load) 12

13 Sensing System Fleet Testing on Urban Cycles (NYC) Generation 1 Generation 2 RF System Configuration (Mack MP-7) DSNY Fleet MY 29 and MY 21+ vehicles over two year (24 months) Antennas mounted directly into DPF assembly Control unit mounted external to aftertreatment system Real-time monitoring and logging of DPF loading state System operation with stock OEM controls 13

14 Fleet Vehicle Data Shows Frequent Regenerations RF sensor measurement data for 15 hr period with stock 29 Volvo/Mack DPF regeneration control system. RF Soot [%] 1% 9% 8% 7% 6% 5% 4% 3% Regeneration at low PM load. RF-DPF [%] T_avg [C] Self-calibration based only on max observed soot load Temperature [C] 2% 2 1% 1 % Time [min] Data from 15 hours with 21 regenerations, avg. 18 min per regeneration OEM control triggers regenerations (~ every 7.1 hrs) at low soot loads Vehicles spends 4% - 5% of operating time in regeneration SAE

15 RF Measured Soot Oxidation to End Regeneration RF measurements can provide direct feedback control to end regeneration. 1% 9% 19.2 min Regen 8 7 DPF Soot Load [% Target] 8% 7% 6% 5% 4% 3% 2% 1% 16.8 min Regen Regeneration Complete Unnecessary Regeneration Average DPF Temperature [C] % Time [min] SAE Back-to-back regenerations occasionally observed due to vehicle shut-down Real-time measurement of soot load can end regeneration when complete 15

16 Summary and Technical Highlights Demonstrated direct measurement of DPF soot and ash levels via RF sensing in test cell and vehicle applications. Technical Highlights Developed single antenna RF system and demonstrated high level of accuracy for DPF soot level measurements Demonstrated combined DPF soot AND ash measurements RF transient response well-correlated with AVL micro-soot sensor Demonstrated fast sensor response < 1 second Evaluated RF performance over 38, mile equivalent DPF aging Fuel savings potential via extend regeneration interval and reduced regeneration duration relative to stock OEM controls Outlook and Additional Applications Current work focused on controls optimization and sensor validation in a range of light-duty and heavy-duty applications with project partners. Additional opportunities for GPF and catalyst applications to monitor gas species adsorbed on catalysts. 16

17 Acknowledgements This material is based upon work supported by the Department of Energy DE-EE5653. Roland Gravel, Ken Howden, and Gurpreet Singh from the DOE Ralph Nine, Trevelyn Hall, and David Ollett from NETL Commercial and National Laboratory Project Partners Corning Incorporated Oak Ridge National Laboratory Daimler Trucks NA / Detroit Diesel FEV DSNY Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. 17