Cleaner, Higher Efficiency Vehicles Using Plasmatrons †

1. Cleaner, Higher Efficiency Vehicles Using Plasmatrons† Daniel R. Cohn Plasma Science and Fusion Center Massachusetts Institute of Technology Presentation to Fusion Power Associates Meeting Washington, D.C., Nov. 21, 2003 †Research supported by Dept. of Energy Office of FreedomCAR and Vehicle Technologies and by ArvinMeritor

2. Team • MIT PLASMA SCIENCE AND FUSION CENTER • L. Bromberg • D.R. Cohn • A. Rabinovich • K Hadidi • N. Alexeev • A. Samokhin • J. Palaia • MIT SLOAN AUTOMOTIVE LABORATORY • J. Heywood • J. Goldwitz • N. Margarit • G. Ziga • ARVINMERITOR • Major US automotive and heavy truck components manufacturer • Commercializing technology licensed from MIT • R. Smaling et. al.

3. Lower Emission, Higher Efficiency Gasoline Engine Gasoline (e.g. 25%) Hydrogen-rich gas (H2+CO) Onboard PlasmatronFuelConverter Ultra lean Burn Gasoline engine Fuel Tank Gasoline (e.g. 75%) • Reduced pollutants (NOx) • Increased efficiency

4. Uses of Onboard Hydrogen Generation  Gasoline Engine Cars And Other Light Duty Vehicles  Hydrogen combusted along with gasoline in engine  Lower emissions (from ultra lean operation)  Higher efficiency (from ultra lean operation, higher compression ratio, strong turbocharging)  Diesel Engine Trucks and Buses  Use in exhaust aftertreatment system  Facilitates attractive exhaust aftertreatment system for reduction of NOx (nitrogen oxides are a primary source of smog)

5. Plasmatron Reformer  Compact (e.g. 2 liter) device for onboard reforming of hydrocarbon fuels (gasoline, diesel, bio-oils, other fuels) into hydrogen-rich gas  Reforming promoted by special electrical discharge

6. Production of Hydrogen Rich Gas From Partial Oxidation Reforming • Add sufficient oxygen from air to bind all carbon in fuel as CO; • For iso-octane (representative of gasoline): C8H18 + 4 (O2 + 3.8 N2) --> 8 CO + 9 H2 + 15.2 N2 • Reaction is mildly exothermic • ~ 15% of energy released in the reformation process • Relatively slow reaction • Difficult to provide effective reforming under transient conditions

7. Plasmatron Reformer • Provides continuous volumetric initiation of reforming reactions • Use of a special low current, high voltage distributed plasma • Advantages • Rapid startup and transient response • Relaxation or elimination of reforming catalyst requirements (conventional reformer catalyst vulnerability has been a major impediment) • Inhibits soot production • Compact • Efficient • Applicable to a wide range of fuels including difficult to process fuels (diesel, bio-oils)

8. Low current gasoline plasmatron Power W 250 Plasma current A 0.1 - 0.4 2 Volume liter Weight kg 3 H2 flow rate slpm 10-200

9. Plasma created in the a gas flow • Gas flow stretches the plasma • Plasma extinguishes and re-establishes (1 kHz) • Discharge over a large volume END VIEW

10. Plasmatron Hydrogen Enhanced Turbocharged Gasoline Engines Moderate fraction (20% - 30%) of gasoline converted into hydrogen-rich gas Addition of hydrogen-rich gas improves both combustion stability resistance to knock (undesired detonation or “pinging”) Increased knock resistance allows high compression ratio and strong turbocharging Net efficiency increase of up to 30% Engine efficiency can be substantially increased by Ultra lean burn (high air/fuel ratio) High compression ratio Strong turbocharging (allows for engine downsizing)

11. Gasoline engine testing at MIT • Hydrogen enhanced combustion stability allows very lean burn (high air to fuel ratio) without misfire • Naturally aspirated (no turbocharging) with conventional compression ratio • Ultralean operation increases efficiency 15% and decreases NOx by a factor of 50 Leaner operation Lambda Leaner operation SAE-2003-01-0630 Lean burn characteristics of a gasoline engine enriched with hydrogen rich gas from a plasmatron fuel reformer E. Tully and J.B. Heywood MIT Dept. of Mechanical Engineering and Sloan Automobile Laboratory Lambda

12. High Compression Ratio, High Boosted Operation through Improved Knock Resistance • Recent experimental studies at MIT Sloan Automobile laboratory show that knock resistance is substantially improved by addition of hydrogen rich gas to gasoline • Octane rating number (ORN) has been increased by 20 ORN when 25% of fuel energy is from hydrogen-rich gas (for reference, the octane rating number difference between regular and premium gasoline is 6) • The combination of enhanced knock resistance and enhanced combustion stability are projected to increase gross engine efficiency by a factor of up to 1.4 and net efficiency by up to 1.3

13. Plasmatron Hydrogen Enhanced Turbocharged Gasoline EnginesRough Projections

14. Status and Prospects Plasmatron hydrogen enhanced turbocharged gasoline engines • Tests on engines in the laboratory • Ultimate goal is up to 30% increase in net efficiency with further decreased emissions from already low emissions • Could be economically attractive: • Additional cost projected to be around $1,000 including the cost of the turbocharger • Pay back time from fuel savings significantly less than life of vehicle • Next step involves vehicle tests by ArvinMeritor team

15. Diesel Engine Emissions Aftertreatment Concept Normal Operation Regeneration Small side stream of diesel fuel Exhaust from engine (Oxygen rich) Hydrogen rich gas NOx Absorber Catalyst Plasmatron Reformer Absorber Catalyst Clean exhaust Clean exhaust Advantages of regeneration with H2-rich gas: • Greater operating temperature range (down to about 130 C) • Greater regeneration effectiveness (fuel penalty decreased by a factor of 2) • Reduced sulfur effects on system

16. H2-Assisted NOx Trap: Test Set-up Power Air Fuel Reformer Fuel Reformate NOx Trap A To Tailpipe Brake Valve Engine NOx Trap B Switching Valve

17. NOx Adsorption Comparison – Bus Road Load Same Fuel Penalty Plasmatron hydrogen regeneration Diesel regeneration

18. Bus H2-Assisted NOx Trap Installation Fuel Reformer Box NOx Trap: 21L/leg Access Door

19. Prospects Diesel Exhaust Treatment • EPA requirements demand implementation of effective exhaust aftertreatment system in heavy trucks and buses in 2007-2010 time frame • Present heavy vehicles use no exhaust aftertreatment • Plasmatron hydrogen enhanced NOx trap aftertreatment is one of the most promising technologies to meet this need

20. Summary • Onboard plasmatron hydrogen generation could improve efficiency and reduce emissions of both gasoline and diesel engine vehicles • The environmental and economic attractiveness of plasmatron enhanced turbocharged gasoline engine vehicles could facilitate widespread use. Widespread use could result in a significant impact on average fuel efficiency • If average fuel efficiency of US fleet of cars and light duty vehicles is increased by 20%, yearly fuel savings would be 25 billion gallons of gasoline (equivalent to 70% of oil presently imported from the Middle East)

21. Summary (continued) • Use of onboard hydrogen generation for improving internal combustion engine vehicles could provide substantial impact much sooner than use of hydrogen fuel cells • Could be first step towards longer term vision of hydrogen fuel cell vehicles. Next step could be use of a small amount of stored hydrogen.