CLEERS Workshop April 28, 2015

Transcription

1 Real-Time Particulate Filter Soot and Ash Measurements, Optimized Control, and Diagnostics via Radio Frequency Sensing CLEERS Workshop April 28, 2015 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): ,

3 Measurement of Aftertreatment State Variables Conventional Exhaust Sensors Measure properties of exhaust gas directly Temperature, Pressure Gas Composition, Particle Content Provide only indirect indication of DPF state Often require complex models or calibration to estimate state of aftertreatment device RF Based Exhaust Sensing RF signal propagates through ceramic media Must be non-conducting Responds to changes in dielectric properties of aftertreatment device Provides a direct measure of the aftertreatment device s loading state 3

4 Many Factors Impact DPF Loading State Determination m in m ox m out Soot and Ash Plugging Image: SAE Source: K. Aravelli DPF Loading State and Current Approach Pressure drop ( P) and model based controls to estimate loading Low-exhaust flow (idle), transients, regeneration, non-uniform soot distribution and oxidation in the wall pores are challenging for P Loading state of filter continually changing with ash over lifetime Accurate sensing required to optimize fuel consumption and filter life 4

5 RF Measurement System Configuration and Operation 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 5

6 Resonance Measurements and Spatial Sensitivity Transmission [S12] * Adam, Stephen, F., Microwave Theory and Applications, Prentice Hall, Inc., Engelwood Cliffs, New Jersey, Frequency 6

7 Motivation: Aftertreatment Controls Optimization Motivation: Enable reduced energy consumption, cost, and increased durability of particulate filter systems through improved sensing and controls. Total FEP (Ref) Fuel Penalty Regeneration Total FEP P RF Sensing Advanced Controls Regeneration Interval DPF Materials Concept: Apply inexpensive radio frequency (RF) technologies to directly monitor DPF soot and ash levels and distribution with low- P DPF materials. Direct measure of loading state advanced feedback controls. Additional advantages with alternative fuels and advanced combustion Adaptive controls as system ages (ash accumulation) ATS Controller RF Sensors ECU Applications for OBD DPF DOC 7

8 Technical Highlights: Parallel Testing Activities Technical Focus Areas Performance Metrics Develop RF sensors Sensor calibration PM/Ash loading Advanced DPF materials Mercedes engine test (LD) Navistar engine test (HD) AVL benchmarking TEOM benchmarking Fuels& adv. combustion Pressure drop (OE) Gravimetric PM Gravimetric Ash P + Models AVL micro-soot Gravimetric PM/Ash AVL micro-soot, TEOM Pressure drop Gravimetric PM/Ash Controls development DDC engine platform aftertreatment Stock OEM controls ( P + Model) Gravimetric PM/Ash On-road fleet test Volvo/Mack trucks ( 09 & 13) 24 Months total, up to 4 trucks Stock Volvo/Mack DPF controls On-road durability 8

9 Single Probe RF Sensor Integration for DPF Control Hardware and System Setup MY 2013 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

10 Single Probe RF Sensor Integration for DPF Control Stock aftertreatment system with 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 g/l 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

11 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% - 30% 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

12 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 12

13 RF Signal (RAW) [RAW] MAF [kg/hr] Transient Response Well-Correlated with AVL MSS :54 11:57 12:00 12:02 12:05 12: :11 12:14 12:17 12: Fast transient response to small changes in engine-out PM RF AVL MSS Intergal TEOM RF slope change due to EGR steps 1 MAF (EGR) Torque RF Parameter Rate 60 11:54 11:57 12:00 12:02 12:05 12:08 12:11 12:14 12:17 12: Time [hh:mm] RF 1 RF Differential AVL MSS AVL MSS 2 11:54 11:57 12:00 12:03 12:06 12:09 Time [hh:mm] TEOM PM [µg], AVL PM (integrated, mg) Torque [ft-lb] 4 Testing on 1.9L GM turbo-diesel at ORNL Catalyzed cordierite DPF DPF DOC 5 AVL GM 1.9L Hz sampling rate for AVL MSS and TEOM 2.5 Hz sampling rate for RF sensor 13 0 Soot [mg/m^3]

14 RF (Derivative) Throttle [%] RF Signal [Raw] Transient Response Details of Throttle Tip-In Events 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 TEOM PM [ug], [µg], AVL AVL MSS (Integrated, mg) 14

15 Ash Distribution Impacts Performance Over DPF Life Ash distribution and deposit characteristics may result in very different P measurements for same ash level in DPF. ~2X Passive Active Source: SAE Source: SAE

16 DPF Soot Load Measurements with Ash RF Soot [g/l], dp Soot [g/l] PM Load [g/l] RF 3 g/l PM Comparison dp Ash Load [g/l] Gravimteric Soot [g/l] RF and dp ( P) measurements both scaled to 0 g/l ash case to develop simple calibration function g/l RF soot load measurements unaffected by ash unlike P RF_Ash 0g RF_Ash 10g RF_Ash 20g RF_Ash 30g RF_Ash 40g RF_Ash 50g 1:1 dp_ash 0g dp_ash 10g dp_ash 20g dp_ash 30g dp_ash 40g dp_ash 50g +0.5 g/l -0.5 g/l 16

17 Sensing System Fleet Testing on Urban Cycles (NYC) Generation 1 Generation 2 RF System Configuration (Mack MP-7) DSNY Fleet MY 2009 and MY 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 17

18 Fleet Vehicle Data Shows Frequent Regenerations RF sensor measurement data for 150 hr period with stock 2009 Volvo/Mack DPF regeneration control system. RF Soot [%] 100% 90% 80% 70% 60% 50% 40% 30% Regeneration at low PM load. RF-DPF [%] T_avg [C] Self-calibration based only on max observed soot load Temperature [C] 20% % 100 0% Time [min] Data from 150 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

19 RF Measured Soot Oxidation to End Regeneration RF measurements can provide direct feedback control to end regeneration. 100% 90% 19.2 min Regen DPF Soot Load [% Target] 80% 70% 60% 50% 40% 30% 20% 10% 16.8 min Regen Regeneration Complete 30 min Unnecessary Regeneration Average DPF Temperature [C] 0% 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 19

20 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 380,000 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 20

21 Acknowledgements This material is based upon work supported by the Department of Energy DE-EE 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. 21