Particle Size Distribution Measurements from Early to Late Injection Timing Low Temperature Combustion

Transcription

1 Particle Size Distribution Measurements from Early to Late Injection Timing Low Temperature Combustion Christopher Kolodziej, Jesús Benajes, Ricardo Novella, Simon Arthozoul CMT Motores Térmicos Universidad Politécnica de Valencia 1

2 Background Experimental Setup Combustion Results Particle Emissions Results Conclusions 2

3 Introduction Premixed, Diesel Low Temperature Combustion (LTC) can greatly reduce NOx and particulate matter (PM) emissions HC and CO emissions optimization required PM emissions possible at minimum opacity-based detection limits through early or late injection timing What are the differences between particle size distributions below opacity-based minimum detection limit? How does PM mass (opacitybased) and number correlate? 3

4 Objectives Find a low PM, NOx, CO, and HC HD-Diesel engine operating regime with minimal intake pressure, EGR cooling, and EGR rate requirements Correlate emissions of particle sizes and numbers to calculated in-cylinder combustion values Provide LTC particle size and number emissions information to combustion as well as after-treatment researchers 4

5 1 Effect of Inj. Timing on Particulate Matter.8 PM Opacity [g/kg_f]

6 Conv. Diesel Particulate Matter (PM) Kittelson Model The nuclei mode typically contains 1-2% of the particle mass and more than 9% of the particle number. Kittelson, J. Aerosol Sci., 1998 Typical Distribution Engine Exhaust Gas Kawai Model Hypothetical model for Diesel nano-particle distribution. Montajir, Kawai, Goto, Odaka, SAE dn / d log Dp Distribution of Volatile Fraction (H 2 O vapor + HC) Distribution of Core Distribution of Solid Particles Log D p 6 1 nm 3 nm 1 nm 1 nm

7 Background Experimental Setup Combustion Results Particle Emissions Results Conclusions 7

8 Experimental Equipment Research Engine Exhaust Dilution Opacity-Based PM Particle Size Dist. 1.8L Single-Cylinder, 14.4:1 CR Dekati FPS-4, Heated Prim. and Ambient Sec. Dilution AVL 415 Smokemeter TSI SMPS 3936 (38L Long DMA, CPC 31) 8

9 Schematic of Dilution System Engine Exhaust Primary Diluter Perforated Tube Probe Pre-probe Secondary Diluter Ejector Flow Divider Primary Dilution Air (from valve unit) Dilution Air Heaters Secondary Dilution Air (from valve unit) T3 T4 Primary Probe Heater T1 Pressure Transducers AVL 415 Smoke Meter Gas Analyzer SMPS 9

10 Dilution Conditions Case 1 2 Intake O2 [%] Exhaust T [C] Probe T [C] 3 29 PDT Setpt. [C] 3 PDT [C] SDT [C] 28 TDR [-] 4 4, 65 Intake O2 = Engine Intake Oxygen Concentration (Volumetric) Exhaust T = Exhaust Sample Point Temperature Probe T = Heated Diluter Sample Probe Temperature PDT Setpt. = Primary Dilution Temperature Heater Setpoint PDT = Actual Primary Dilution Temperature SDT = Secondary Dilution Temperature TDR = Total Dilution Ratio 1

11 Engine Operating Conditions Case Speed [RPM] IMEP [bar] m fuel [mg/cycle] Inj. Command [ atdc] Mech. Inj. Delay [CAD] P injection [bar] Intake O2 [%_vol] Equivalence Ratio [-] T intake [ C] P intake [bar] T exhaust [ C] P exhaust [bar] ~

12 Background Experimental Setup Combustion Results Particle Emissions Results Conclusions 12

13 Max. Adiabatic Flame T [K] Flame Temperature and NOx Emissions NOx [g/kg_f]

14 12 CO and HC Emissions 1 CO [g/kg_fuel] HC [g/kg_f]

15 Background Experimental Setup Combustion Results Particle Emissions Results Conclusions 15

16 1 PM Zones Legend PM Opacity [g/kg_f]

17 Ignition Delay [CAD] In-Cylinder Pre-Mixing and Oxidation Injection Duration 8.25 PM Opacity [g/kg_f] % Burn Adiab. Flame T [K]

18 Concentration [#/cc] 1.E+9 1.E+8 1.E+7 1.E+6 1.E+5 Particle Size Distributions Case Concentration [#/cc] 1.E+9 1.E+8 1.E+7 1.E+6 1.E+5 Case E Diameter [nm] 1.E Diameter [nm] 1 PM Opacity [g/kg_f]

19 Particle Size Distributions Concentration [#/cc] 1.E+9 1.E+8 1.E+7 1.E+6 1.E+5 Case 1 Pivot Point Concentration [#/cc] 1.E+9 1.E+8 1.E+7 1.E+6 1.E+5 Case 2 Pivot Point E Diameter [nm] 1.E Diameter [nm] 1 PM Opacity [g/kg_f]

20 Concentration [#/cc] 1.E+9 1.E+8 1.E+7 1.E+6 1.E+5 Particle Size Distributions Case 1 Case E E+8 Concentration [#/cc] 1.E+7 1.E+6 1.E E Diameter [nm] 1.E Diameter [nm] 1 PM Opacity [g/kg_f]

21 Concentration [#/cc] 1.E+9 1.E+8 1.E+7 1.E+6 1.E+5 Early vs. Late Minimum PM Injection Case Concentration [#/cc] 1.E+9 1.E+8 1.E+7 1.E+6 1.E+5 Case E Diameter [nm] 1.E Diameter [nm] 1 PM Opacity [g/kg_f]

22 Accumulation Mode (>5nm) 1.8 PM Opacity [g/kg_f] Total Concentration [#/cc] 1.E+9 1.E+8 1.E %O2 Accumulation Mode [#/cc] 1.E+1 1.E E+6 1.E+8

23 Nucleation Mode [nm] 1.E+11 1.E+1 1.E+9 Nucleation Mode (<5nm) Total Concentration [#/cc] 1.E+9 1.E+8 1.E+7 1.E %O2 HC [g/kg_f] E+8

24 Background Experimental Setup Combustion Results Particle Emissions Results Conclusions 24

25 Conclusions Within, PM mass and number emissions increased rapidly with advancing injection timing (due mostly to decreasing ignition delay) In, PM mass and number emissions decreased with injection timing advance (due to increased ignition delay and 85% burned adiabatic flame temperature) Strong trade-off between accumulation and nucleation modes existed in (pivot point) 1 PM Opacity [g/kg_f]

26 Conclusions (Cont.) showed increased PM mass and number in both accum. and nucl. modes with injection timing advance, but much greater nucleation mode increase than accumulation mode Since HC emissions also dramatically increased from -3 atdc to -33 atdc, spray-combustion chamber impingement is suspected as primary cause of increased PM Though minimum-pm injection timings had similar accumulation modes, later injection timings had higher nucleation modes, accompanied by higher HC emissions 1 PM Opacity [g/kg_f]

27 Acknowledgements Spanish Ministry of Education Universidad Politécnica de Valencia Gabriel Alcantarilla Rogério Jorge Amorim Sara Goska Thank You for Your Kind Attention Questions? 27 Christopher Kolodziej