The Natural Choice

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The Natural Choice
G3300-G3500 Fuel Systems
December 2000

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gas
Carbureted Fuel Systems G3500 - G3300

• gas shut-off valve
• gas pressure regulator
• load adjustment valve
• carburetor

The Natural Choice
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Gas Shut-off Valve

• Provides positive shut-off of fuel supply
• Located at fuel supply connection

gas shut-off valve

The Natural Choice
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• Gas Shut-off Valve

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Gas Pressure Regulator
balance line

• Maintains a fixed pressure difference between
  carburetor air inlet and carburetor fuel supply

gas pressure regulator

The Natural Choice
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• Gas Pressure Regulator

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Mixture Adjustment Valve

• Adjusts air/fuel ratio at full load
• Located on or near carburetor

mixture adjustment valve

The Natural Choice
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• Mixture Adjustment Valve

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Carburetor
carburetor

• Mixes volume of fuel per volume of air
• Effective for a limited range of LHV's
• Requires a constant fuel supply pressure

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• Carburetor

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• Fuel System Operation

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high pressure gas fuel system
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low pressure gas fuel system
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Fuel System Operation

• Air supplied to carburetorturbo compressor
  provides boost for more power
• Fuel supplied to carburetorgas shut-off valve,
  regulator, balance line
• Air/fuel mixture supplied to cylindercarburetor,
  throttle
• Combustion cycle in cylindervalves, spark plug,
  piston
• Exhaust routed through turbochargerturbine uses
  exhaust energy to drive compressor

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• High vs. Low Pressure Gas

• Locates carburetor (mixer and throttle) after
  turbocharger
• Shorter fuel path means better transient response
• Turbo works less, aftercooler heat rejection is
  lower

high pressure gas fuel system layout
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• High vs. Low Pressure Gas

• Mixer located before turbocharger, throttle after
• Lower fuel pressure meets building code
• Aftercooler is exposed to fuel
• Inlet air temp can affect air/fuel ratio

low pressure gas fuel system layout
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Air-To-Fuel Heat Exchanger

• Equalizes air and fuel temperatures to maintain
  air/fuel ratio as ambient temperature changes
• Requires low pressure gas

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Air-To-Fuel Heat Exchanger

• Air to fuel heat exchanger

The Natural Choice
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• Air/Fuel Ratio Control

air/fuel ratio control

• Active control monitors engine operating
  parameters to maintain desired air/fuel ratio as
  conditions change
• Effective for a limited range of LHV's

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• Air/Fuel Ratio Control

• Active control reduces variability due to fuel
  and environment
• constant emissions with varying load
• lower emissions
• higher ratings
• Tightly controlled emissions levels allow
  catalyst operation without fouling
  (TA-stoichiometric engines with aftermarket AFRC)

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Air / Fuel Ratio Control G3500 High Pressure Gas
AFRC

• G3500 high pressure gas system layout

The Natural Choice
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Air / Fuel Ratio Control G3500 High Pressure Gas
AFRC

• Price list arr. for high pressure gas industrial
  G3516 LE and G3512 LE
• Maintains NOx at constant level from 100-50
  load and across lug range
• Effective for fuels 850-1275 btu/scf(33.4-50.1
  MJ/Nm )
• Electronic governoris integral to system

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The Natural Choice
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Optional Fuel Systems

• Vaporized propane
• Low energy biogas
• landfill gas
• digester gas
• Dual gas fuel systems

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• Optional Fuel Systems
• Fuel System Availability

std standard opt optional ser
special engineering request n/a not available
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Dual Gas Fuel System

• Dual gas regulators for high pressure gas TA or NA

secondary fuel regulator load adjustment
valve (high energy fuel)
primary fuel regulator (low energy fuel)

The Natural Choice
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Dual Gas Fuel System

• Provides backup fuel system to allow operation in
  the event of failure of the primary fuel system
• Engine configuration must be compatible for
  operation on either fuel
• Availability of dual gas systems from the factory
  depends on the engine family and fuel types
  please consult an applications engineer for help

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Dual Gas Fuel System

• High pressure/low pressure system(available on
  G3500 only)

The Natural Choice
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Dual Gas Fuel System

• Fuel switching equipment must be provided by the
  customer
• Ignition timing changes for different fuel must
  be accommodated
• Engine ratings must be determined for both fuels

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Fuel System Considerations

• Fuel pressure provided to the regulator must meet
  specifications(see chart or price list
  description)
• Gas pressure regulators require fuel temperatures
  between 150F to -20F
• Fuel filters are required to avoid potential
  engine damage
• particles
• liquids

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Fuel System Requirements
Gas Supply Pressure
psi
kPa

• G3300
• low pressure gas
• high pressure gas
• G3400
• low pressure gas
• high pressure gas
• G3500
• low pressure gas
• high pressure gas
• low emission (81)
• low emission (111)
• stoichiometric TA
• naturally aspirated

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Gas Engine 101

Agenda Gas Engine Basics 800am-Doug
Morse Fuels 900am-Doug Morse Fuel
Systems 930am-Doug Morse -G3300-G3500 -G36
00 Cooling Systems
1030am-Greg Nagel -G3300-G3500 -G3600 Emi
ssions 1130am-Doug Morse