Partially Premixed Combustion

Home , Compression ratio, Cylinder (engine)

Arne Andersson Magnus Christensen

DEER 2011 Conference High Load Low Temperature Combustion - enabled by introduction of “new” fuels

RCCI PPC ´Reactivity Controlled CI´ Partially Premixed Combustion very high ON +very high CN in-between ON/CN i.e. neat ethanol + Diesel i.e. Naphtha or gasoline/diesel IMEP 17 bar w/o EGR reported IMEP 26 bar achieved

Low load

High load CETANE CETANE

OCTANE OCTANE Power density - a prerequisite for downsizing and transport efficiency

Volvo Technology Arne Andersson, DEER 2011 PPC use a gasoline type fuel

600 Single injection Prail = 2400bar Prail = 1500bar 500 • BSNOx ~ 0.5g/ Low Cetane 400  ignition delay reduce soot (more premix) 300  increase efficiency (faster heat release) 200

 Low load problems (noise, HC+CO) aRoHR [J/CAD] & Pcyl [bar] 100

330 340 350 360 370 380 390 400 • High volatility Crank Angle Position [edeg]  No wall wetting; Inject anytime!

• Low viscosity  A lubricity additive needed

Volvo Technology Arne Andersson, DEER 2011 CR requirement for ignition HCCI test for PRF blends

ignition becomes demanding for ON > 80 CR>17 needed for cold start?

Diesel is similar to PRF 30

Port injected PRF0 to PRF100

Volvo Technology Arne Andersson, DEER 2011 Controlling CO and HC at low load

uncooled EGR setting: Inlet Manifold Temp raised from 38 to 70 C

We must do more at lower loads!

Volvo Technology Arne Andersson, DEER 2011 Ways to improve temperature at TDC

50 1200 45 1100 40 1000 35 ε = 15.8 900 30 ε = 17.3 800 25 VVA 50°

Pcyl (bar) Pcyl trottle 20 (K) Tcyl 700 hot EGR

15 600

10 500

5 400 0 300 -90 0 90 -90 0 90 CAD CAD Influence on in cylinder temperature at TDC by: increased compression ratio, Miller, intake throttling and hot EGR Hot EGR still the best

Volvo Technology Arne Andersson, DEER 2011 Exhaust re-breathing is another way to increase in cylinder temperature

1600

1400

1200

1000

ref 800 T(K) rebreathing

600

400

200

0 -90 0 90 CAD In Cylinder temp with and without re-breathing

Re-breathing

Volvo Technology Arne Andersson, DEER 2011 PPC test results with single stage turbo boundary conditions

A load sweep from IMEP 8 to 21 bar From premixed to diffusion combustion

Volvo Technology Arne Andersson, DEER 2011 1200rpm/IMEP8, soot free combustion at very low NOx

1200rpm / IMEP 8 NOx/Soot trade-off Gross Indicated Efficiency 0.10 60 VSD Pinj: 2400bar ON87, build 1 0.08 ON87, build 1 ON87, build 2 55 ON87, build 2 0.06 ON87, build 3 ON87, build 4 50 ON87, build 3 0.04

ON87, build 4 Efficiency [%] Efficiency BSSoot [g/kWh] BSSoot 0.02 45

0.00 40 0.0 0.5 1.0 1.5 2.0 0.0 0.5 1.0 1.5 2.0 BSNOx [g/kWh] BSNOx [g/kWh]

Soot free due to premixing Note that diesel is injected at 2400 bar

Volvo Technology Arne Andersson, DEER 2011 …COMPARED TO VSD10 1200rpm/IMEP12, significant potential on soot and BSFC with gasoline type fuel

1200rpm / IMEP12 NOx/Soot trade-off Observed BSFC 0.12 VSD10 VSD10 2400bar 2400bar 0.10 ON87 1500bar 225 N 1 220 ON87 0.08 215 1500bar 0.06 210 0.04 205

BSFC [g/kWh] BSFC 200 BSSoot [g/kWh] BSSoot 0.02 195 0.00 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.5 1.0 1.5 2.0 2.5 BSNOx [g/kWh] BSNOx [g/kWh]

One reason for improved BSFC is shorter combustion duration

Volvo Technology Arne Andersson, DEER 2011 IMEP12 – Rate of Heat Release example

Diesel 2º CAD ignition delay Gasoline 8º CAD ignition delay

600 Single injection VSD10Prail = 2400bar 2400 (VSD10) bar Prail = 1500bar (ON87) 500 ON87 1500 bar BSNOx ~ 0.5g/kWh RoHR tail is identical!

400 The later part of the combustion is mixing controlled 300 Global mixing is still a major design target! 200 aRoHR [J/CAD] & Pcyl [bar]

100

330 340 350 360 370 380 390 400 410 420 Crank Angle Position [edeg]

Volvo Technology Arne Andersson, DEER 2011

1800rpm /IMEP21

EGR percentage Observed BSFC VSD10 35 VSD10 2000bar 220 ON87 2000bar ON87 1700bar 30 215 1700bar

Same

EGR [%] 210

25 EGR level 205

20 BSFC [g/kWh] BSFC 0.5 1.0 1.5 2.0 2.5 3.0 3.5 200 BSNOx [g/kWh] 195 1800rpm / 100% NOx/Soot trade-off 0.5 1.0 1.5 2.0 2.5 3.0 3.5 BSNOx [g/kWh] 0.30 VSD10 2000bar 0.25 ON87 1700bar Slightly improved BSFC

0.20

0.15 0.10 BSSoot [g/kWh] BSSoot 0.05 Still almost soot free at 2 g NOx! 0.00 0.5 1.0 1.5 2.0 2.5 3.0 3.5 BSNOx [g/kWh]

Volvo Technology

Arne Andersson, DEER 2011 C100 SST

Sum up of test results

With easy to achieve boundary conditions we can:

• Run almost soot free at all tested loads • Get biggest BSFC benefits at road load • Get very low NOx at road load

Volvo Technology Arne Andersson, DEER 2011 Transport system implications from “new” fuels need to be investigated

• Well To Tank analysis, WTT • Availability • Bio content capability • ….

Volvo Technology Arne Andersson, DEER 2011 Compression Ignition with Diesel/Gasoline Blends

Diesel 35% + Gasoline 65% = PRF 80 (ON)

Volvo Technology Arne Andersson, DEER 2011 Well To Tank efficiency GM/Argonne report using GREET (2001, 2005)

79.9%

86.4%

Naphtha 8% more Efficient!

Volvo Technology Arne Andersson, DEER 2011 Conclusions

• Potentially more than 10% lower CO2 foot print with PPC/Naphtha • Significant soot, NOx and efficiency gains from using PPC • Significant engine design changes needed to handle low load

Volvo Technology Arne Andersson, DEER 2011 Acknowledgements

This material is based upon work supported by – Department of Energy National Energy Technology Lab under Award Number DE-EE0004232 – Department of Energy National Energy Technology Lab under Award Number DE-FC26-07NT43222

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.

Volvo Technology Arne Andersson, DEER 2011