Soot and NOx Emissions Reduction in Diesel Engines via by variablepitch339

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									Soot and NOx Emissions Reduction in Diesel Engines via Spinspray Combustion
Mike Bergin, Rolf D. Reitz, Randy P. Hessel
Acknowledgement: Anonymous industry sponsor and DOE/Sandia
Non Road Engine Geometry and Operating Conditions
Bore Bore/Stroke Cylinder Head Combustion Chamber Displacement Injection system Engine Speed and SOI Approx. 225 (mm) 0.78
Normalized Pressure (P/Pmax)
0.3 0.2 0.1 0.0

Model Validation
Early SOI
0.3

Late SOI RPM 444
0.2 0.1 0.0 0.4

Genetic Algorithm Optimization
•The current (2006) non-road EPA emissions targets do not appear to require the use of aftertreatment or EGR •Fuel economy increases without exceeding emissions or changing engine geometry were sought Tiltxy 2 allowed to float from 15 to 45 degrees

4-valve low swirl Quiescent (bowl dia = 0.83*bore) Approx. 15.0 (L)/cyl Unit injector (8 holes) Case 1 444 RPM Early SOI Case 2 444 RPM Late SOI Case 3 888 RPM Early SOI Case 4 888 RPM Late SOI Case 5 1050 RPM Early SOI (baseline) Case 6 1050 RPM Late SOI

Optimization Parameters

0.4 0.3

The engine operated with two independent rows of injector holes
parameter fraction of sector fuel mass to hole 1 min 20% max 50%

0.3

0.2 0.1 0.0
1.0 0.8 0.6 0.4 0.2 0.0

RPM 888

0.2 0.1 0.0
1.0 0.8 0.6

injection velocity

300 (m/s) (700 Bar) -10 ATDC -10 ATDC 70 deg 70 deg 15 deg

550 (m/s) (1700 Bar) +10 ATDC +10 ATDC 80 deg 80 deg 45 deg

Tiltxy 1 fixed at 15 degrees from edge

SOI hole 1 SOI hole 2 tiltxz hole 1 tiltxz hole 2 tiltxy hole 2

RPM 1050 Baseline
-100 -50 0 50 100

0.4 0.2 0.0 -100 -50 0 50 100

Tiltxz 1 and 2 allowed to float from 70 to 80 degrees

Non Road engines used in construction mining and marine applications

100
Optimum of GA

Optimized Injection profile Note the peak in the middle (CA 7-12) which indicates both holes are injecting simultaneously

Combined sprays have greater penetration (group hole nozzle)

Steep temperature gradient

80 mass flow rate (g/s) 60 40 20 0

Generation Generation 51 51

Conclusions
•Spin-Spray Combustion demonstrated to reduce engineout soot by enhanced mixing (improved soot oxidation) •NOx reduction occurs through rapid convection of burned gas into evaporation region

SOI1
0

SOI2 EOI1
10

EOI2
20 30 40

Crank Angle (deg)

Bowl lip

NOx production curves of optimum and baseline cases
1.00

1.4

Baseline Merit=286

GA optimum Merit=382

R* Simulation/Target

0.75 Normalized NOx
Gen 51 Case 5

Optimum (Gen 51) show a marked change in slope at CA ~ 22

1.2

GA Optimum Retard injection timing Merit=354

Vortex formation is characteristic of “Spin Spray Combustrion”

Future Work
•Increase load. •Combine independent sprays with bowl geometry optimization. •Allow for more than 1 injection from one or both rows of holes.

1.0

•NOx reduced 14% •Soot reduced 51%

0.50

0.8

•gisfc improved 1%
0.6

0.25

0.00 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Crank Angle (deg)

University of Wisconsin Engine Research Center

NOx SOOT gisfc

0.4


								
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