CHARACTERIZATION OF ATMOSPHERIC DISPERSING EXHAUST PLUME DURING ON- ROAD OPERATION OF LATEST TECHNOLOGY HEAVY-DUTY TRUCKS

Transcription

1 CHARACTERIZATION OF ATMOSPHERIC DISPERSING EXHAUST PLUME DURING ON- ROAD OPERATION OF LATEST TECHNOLOGY HEAVY-DUTY TRUCKS Marc C. Besch, Arvind Thiruvengadam, Dan K. Carder, Pragalath Thiruvengadam, Saroj Pradhan, Berk Demirgok, Mridul Gautam West Virginia University, Morgantown, WV University of Reno Nevada, Reno, NV West Virginia University Benjamin M. Statler College of Engineering and Mineral Resources Department of Mechanical and Aerospace Engineering (MAE)

2 BACKGROUND AND MOTIVATION Full Flow Constant Volume Sampling System (CVS) Partial Flow Sampling System (PFSS) On-Road Chase or Dispersing Plume Studies Full Flow Windtunnel Dispersing Plume Studies 115ft 2

3 BACKGROUND AND MOTIVATION Assess the likelihood of reproducing real-world PM size distributions collected from the exhaust plume, by using two methodologies: CVS and Partial-Flow sampling Differences in dilution rates occurring in dispersing plume => enhancement/suppression of nucleation Importance of local turbulence intensity inside plume in enhancement of nucleation mode particle formation Impact of real-world background aerosols on particle formation/evolution in dispersing plume Compare PM development in real-world exhaust plume vs. full-scale windtunnel vs. full-flow CVS vs. partial flow sampling Compare PM morphology and composition via TEM/EDX analysis of PM samples obtained through plume and laboratory sampling 3

4 FROM ON-ROAD CVS EMISSIONS MEASUREMENT Particle size distributions and number concentrations measured in CVS were found to be dependent on engine technology DPF regeneration events increase TPM emissions SCR activity results in particles both in nucleation (e.g. sulfates) and accumulation mode particles Composition and the environmental impact (if any) from these accumulation mode particles is worth investigating Solid particles in the nucleation mode are observed in exhaust of natural gas vehicles a) Data from on-road CVS study suggests that lubrication oil contribution is prevalent even in engines with less miles b) Engine component ageing could potentially increase the PN count from natural gas engines 4

5 FROM FULL-FLOW WIND-TUNNEL STUDIES Experimental modeling work (Gautam et al., 23; Kim et al., 21) indicated that the most important events in PM nanoparticle formation and evolution occur within 2m from the exhaust stack. On-road chase studies (Rönkkö et al., 26) indicate no differences in PM after 5m from exhaust stack. Formation of nucleation mode particles depends upon EC/OC balance in raw exhaust and turbulence intensity (TI) surrounding the exhaust plume. Experimental and modeling work by Littera (214) found increased nucleation mode particle concentrations in areas within the plume with higher TI. Real-world background air, richer in solid nuclei than the HEPA-filtered air used in PFS or CVS systems, promote greater heterogenic nucleation. Dilution air conditions closer to atmospheric values led to better agreement between chase vs. chassis data (Rönkkö et al., 26) Comparison between in-plume and double dilution stage (ejector diluters) sampling from the stack (Brown, 25). Kinsey (26) presented a mobile laboratory for characterization of particulate emissions from heavy-duty diesel truck allowing for in-plume and raw exhaust sampling (partial flow) 5

6 METHODOLOGY Test Vehicles Vehicle Engine Model After Treatment System Vehicle 1 (MY 28) Cummins ISX 525 DPF only Vehicle 2 (MY 214) Detroit Diesel DDC15 DPF and SCR Vehicle 3 (MY 214) Cummins ISL-G 32 (Natural gas) Three-way catalyst Vehicle 1, MY 28, DPF only Vehicle 3, MY 214, Natural gas w/ TWC 6

7 METHODOLOGY - On-Road Plume Sampling Heated manifold (47±5ºC) maintain constant flow through probe split sample to different instruments attach sample holder for TEM grids Exhaust Plume Sample Extraction Cart Adjustable Probe Holder Solenoid Valves Manifold Exhaust Plume Sample Probe Raw Exhaust Sample TSI EEPS SPCS, Horiba TEM Grid Holder CPC,TSI EAD,TSI FTIR Analyzer MFC DMM, Dekati Aethalometer TSI EEPS Ambient Sample Pitot-tube flowmeter Horiba OBS-22 + Horiba OBS-TRPM Semtech-DS Sensors Inc. CPC TSI TSI EEPS Tpost-SCR Double dilution Partial-Flow System Dry, Ambient Temperature, Compressed HEPA Filtered Air Supply Ppost-SCR Ppre-DPF Tpre-DPF Engine ECU Data via J1939 SCR DPF

8 METHODOLOGY - On-Road Plume Sampling Heated and insulated Tygon tube Solenoid Valves Heated Manifold Exhaust stack Hotwire anemometer Enclosure with controls and miniature NDIR sensors 5 sampling probes with adjustable probe position Plume sample probe Each probe is equipped with Extraction probe for miniature NDIR CO2 sensor Thermocouple Continuous CO2 measurement via dedicated NDIR sensor Anemometer for wind speed measurements (center probe only) Sampling lines were characterized for particle losses using AVL APG 8

9 METHODOLOGY - On-Road Plume Sampling Pos. I Pos. II Pos. III Pos. IV Exhaust stack Test Matrix: Nr. Speed / Route Sampling Mode Sampling Valve Direction Pos Time [sec] order 1 SAC to Test Site I - - c and t 2 2mph I Northbound 3 c-t-r-b-l-c 3 2mph II Southbound 3 c-t-r-b-l-c 4 35mph I Northbound 18 c-t-r-b-l-c 5 35mph II Southbound 18 c-t-r-b-l-c 6 35mph III Northbound 18 c-t-r-b-l-c 7 45mph I Southbound 12 c-t-r-b-l-c 8 45mph II Northbound 12 c-t-r-b-l-c 9 45mph III Southbound 12 c-t-r-b-l-c 1 45mph IV Northbound 12 c-t-r-b-l-c 11 Test Site to SAC IV - - c and t Center probe location w.r.t. exhaust stack: Pos Distance Exh. to Height above center probe center I 4 in center II 16 in center III 3 in 24 in IV 6 in 35 in Raw exhaust partial flow sampling system: Parameter 1 st Stage 2 nd Stage Diluter Type Ejector Diluter (AirVac TD11-H) Ejector Diluter (AirVac TD11-H) Dilution Air Temperature ~15 C ~2-25 C Dilution Air Condition Dry, HEPA filtered air Dry, HEPA filtered air Residence Time ~.6sec ~.4sec Dilution Ratio ~7 ~11 9

10 METHODOLOGY Test Route and Matrix Two vehicle operating conditions => engine load conditions Transient vehicle operation Highway (I-5) and urban driving => Depot Park facility (SW Sacramento, CA) to Robbins (NW of Sacramento, CA) Steady-state vehicle operation Reclamation Road located ~39 miles north of Sacramento, CA Steady-state 25 mph Steady-state 35 mph Steady-state 45 mph Test route characteristics Length: ~1.1 miles Average grade ~.4% (peak ~1.6%) North Sacramento ~39 miles 32ft 16ft 1

11 METHODOLOGY - Data Processing PM metrics Total particle number concentration via CPC (TSI Inc.); i) raw exhaust, ii) plume Total particle number concentration compliant with UNECE PMP method via SPCS- 21 (Horiba Inc.); plume Particle active surface information via EAD (TSI Inc.); plume Particle mass information via AVL MSS (AVL GmbH) and DMM (Dekati); plume PM black carbon information via aethalometer AE33 (Magee Scientific); plume Particle number and size distribution via EEPS, model 39 (TSI Inc.); i) ambient air, ii) plume Raw gaseous emissions (Semtech-DS) used to monitor engine/after-treatment activity (i.e., DPF regeneration) and to compute local dilution ratio based on CO 2 with gaseous concentration in plume measured via FTIR (mks 23) TEM grids containing PM samples will be analyzed at the West Virginia University Shared Research Facilities using a JEOL JEM-21 LaB6 Transmission Electron Microscope to analyze particle morphology An Energy-Dispersive X-ray analysis will also be performed to obtain information about PM composition on a particle basis

12 RESULTS Dilution Ratios DR PFS => 1 st stage ~7, 2 nd stage ~11 => DR tot 81 DR CVS => ~1 on average during cruise operation Vehicle 1 -DPF only Vehicle 2 -DPF-SCR 2mph 2mph Pos #1 Pos #2 Pos #3 Pos #4 Pos #1 Pos #2 Pos #3 Pos #4 Center Top Right Bottom Left mph 35mph Pos #1 Pos #2 Pos #3 Pos #4 Pos #1 Pos #2 Pos #3 Pos #4 Center Top Right Bottom Left mph 45mph Pos #1 Pos #2 Pos #3 Pos #4 Pos #1 Pos #2 Pos #3 Pos #4 Center Top Right Bottom Left DPF regeneration event occurring

13 1 RESULTS Plume Identification w/ NDIR Vehicle 1-2mph, Pos #1 Vehicle 1-45mph, Pos #1 Top Top CO2 [ppm] 5 Temp [C] 2 1 CO2 [ppm] 5 Temp [C] Left 3 1 Left 3 CO2 [ppm] 5 Temp [C] 2 1 CO2 [ppm] 5 Temp [C] Bottom 3 1 Bottom 3 CO2 [ppm] 5 Temp [C] 2 1 CO2 [ppm] 5 Temp [C] Right 3 1 Right 3 CO2 [ppm] 5 Temp [C] 2 1 CO2 [ppm] 5 Temp [C]

14 EEPS [#/cm3] CPC [#/cm3] CPC [#/cm3] MSS [mg/m3] SPCS [#/cm3] 1 5 EAD [mm/cm3] DMM [/mug/cm3] RESULTS Vehicle 1, Pos #1, 2 vs 45mph C T R B L 2mph Not corr. for DR PFS EEPS [#/cm3] CPC [#/cm3] MSS [mg/m3] SPCS [#/cm3] 4 2 EAD [mm/cm3] CPC [#/cm3] DMM [/mug/cm3] x mph Not corr. for DR PFS

15 EEPS [#/cm3] 4 x 16 2 T T C RESULTS Transient Test T C T DPF regeneration event during portions of route EAD [mm/cm3] 4 1 x Not corr. for DR PFS SPCS [#/cm3] DMM [/mug/cm3] MSS [mg/m3] CPC [#/cm3] 2 x CPC [#/cm3] => Total particle number concentration via doublestage dilution PFS system Vehicle 1 Transient operation => extra urban and highway driving ~39 miles from test site to Depot Park facility (Sacramento, CA)

16 RESULTS Vehicle 2, 35mph, 3 diff. Pos. EEPS [#/cm3] EEPS [#/cm3] EAD [mm/cm3] 1 1 x EAD [mm/cm3] CPC CPC [#/cm3] [#/cm3] DMM [/mug/cm3] DMM [/mug/cm3] MSS MSS [mg/m3] [mg/m3] SPCS SPCS [#/cm3] [#/cm3] x x CPC [#/cm3] 16 Change measurement plane form 1, 2, to 3 Onset of regeneration event during measurement on second plane

17 CONCLUSIONS Design of exhaust plume sample extraction cart allowing to sample at different locations (axially and radially) within the dispersing exhaust plume. Three test vehicles, i) DPF only (US-EPA 27 compliant; ii) DPF-SCR (US- EPA 21 compliant); iii) stoichiometric natural gas with TWC (US-EPA 21 compliant) Steady-state (2,35, and 45mph) and transient vehicle operating conditions Particle instruments to characterize number, active surface, mass, and black carbon. Additional sample collection on TEM grids for morphology analysis via transmission electron microscopy. Miniature NDIR sensors and thermocouples aided in locating boundaries of dispersing plume Significantly increased particle number concentration in exhaust plume during DPF regeneration event Decoupling of number concentration in raw exhaust and plume at start and end of DPF regeneration event => In-depth data analysis and TEM grid analysis started and currently on-going 17

18 THANK YOU FOR YOUR ATTENTION Marc C. Besch - Marc.Besch@mail.wvu.edu Arvind Thiruvengadam - Arvind.Thiruvengadam@mail.wvu.edu Daniel K. Carder - Daniel.Carder@mail.wvu.edu Mridul Gautam - mgautam@unr.edu Center for Alternative Fuels, Engines and Emissions ACKNOWLEDGEMENT 18