Cleaner, Higher Efficiency Vehicles Using Plasmatrons

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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

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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

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Lower Emission, Higher Efficiency Gasoline Engine
Gasoline (e.g. 25)
Hydrogen-rich gas (H2CO)
Onboard PlasmatronFuelConverter
Ultra lean Burn Gasoline engine
Fuel Tank
Gasoline (e.g. 75)

• Reduced pollutants (NOx)
• Increased efficiency

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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)

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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

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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) --gt 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

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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)

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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
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• 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
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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)

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• 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
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
Leaner operation
Lambda
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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

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Plasmatron Hydrogen Enhanced Turbocharged
Gasoline EnginesRough Projections
Concept Average fraction of fuel reformed Net Efficiency increase Emissions Reduction in gasoline use Comments
Ultra lean operation with conventional powertrain 30 1.3 Extremely low 21 Turbocharged with high compression ratio
Ultra lean operation with hydrid powertrain 30 1.7 Extremely low 40 Increased cost for powertrain
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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

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Diesel Engine Emissions Aftertreatment Concept
Normal Operation
Regeneration
Small side stream of diesel fuel
Exhaust from engine (Oxygen rich)
Hydrogen rich gas
NOx
Plasmatron Reformer
Absorber Catalyst
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

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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
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NOx Adsorption Comparison Bus Road Load Same
Fuel Penalty
Plasmatron hydrogen regeneration
Diesel regeneration
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Bus H2-Assisted NOx Trap Installation
Fuel Reformer Box
NOx Trap 21L/leg
Access Door
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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

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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)

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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.