Natural Gas Engine Maintenance

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Natural Gas Engine Maintenance

• Daniel Polo
• 02.20.09

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Overview

• Natural Gas Fuel Nearly perfect fossil fuel
• Constituents of Natural Gas
• LNG CNG
• Comparison Natural gas vs. Diesel
• Engine Operation, ISL G
• Feedback from End-Users
• Specifications ISL G vs. L Gas Plus
• Maintenance Intervals, ISL G
• Daily Maintenance Procedures
• Maintenance Procedures at 500, 1000, 1500 and
  2000 engine hours

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What is Natural Gas ?

• Nearly perfect fossil fuel
• Clean burning less damaging to environment
• Its constituents are
• Methane or CH4 (70-90)
• Major constituent of Natural Gas
• Octane Rating of 140
• Burns at higher temperature (1300 F)
• Resistant to Pre-ignition
• To maintain this octane rating the methane
  content of natural gas must have a 90
  concentration or a methane number greater than 80
  (65 for wide range fuel)
• When the methane number is below specifications,
  this will result in poor performance and possible
  engine damage
• The methane content will decrease when other
  gases increase thus lowering the octane rating of
  the fuel causing pre-ignition and subsequent
  engine damage.
• Ethane or C2H6 (0-20)
• Propane or C3H8 (1.7)
• These gases all burn in the combustion process
  and vary according to the region where the gas
  was recovered and sometimes vary according to the
  time of year it is supplied to the user

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Natural Gas Familiarization

• Two widely used forms of storing natural gas on
  vehicles
• Compressed Natural Gas (CNG)
• Compressed on storage vessels on vehicle at
  operating pressures of 3000 to 3600 psig
• Liquefied Natural Gas (LNG)
• In the liquid state, the vehicle can carry more
  fuel in a smaller area
• LNG is produced through a cryogenic process in
  which the gas is cooled to -258 degrees F. At
  that temperature NG becomes a liquid
• The odorant normally added to natural gas will
  solidify above these temperatures, thus LNG used
  in vehicles will not have the familiar gas odor
• Typically natural gas gets approximately 20
  fewer miles per gallon than diesel

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Natural Gas vs. Diesel

• Diesel
• 1 U.S. gallon weighs 7.1 lbs.
• Heating value is 18,250 Btu per lb and 129,575
  Btu per gallon.

• Natural Gas
• 1 U.S. gallon of LNG weighs 3.4 lbs.
• Heating value of LNG is 21,500 Btu per lb, and
  73,000 Btu per gallon.
• Heating value of 140 SCF of NG is 129,575 Btu

Using mileage data and the above information,
plus keeping in mind that the thermal efficiency
of a natural gas engine is 20 less then diesel,
you will need about twice the fuel volume to
match the range produced by the diesel engine.
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CNG Considerations
Oil Carryover from Fueling Station Compressors

• The natural gas compressors must be well
  maintained to minimize the migration of oil
  around the piston and ring pack, which
  contaminates the fuel. When oil contamination is
  excessive, pressure regulators, laminar flow
  devices and other engine components may become
  restricted decreasing engine performance and
  damaging engine components. Multiple filters and
  traps must be used to minimize compressor oil in
  the fuel.

CNG fueling Satiation Compressors
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Operating the ISL G

• Depending upon the drivers previous equipment,
  the ISL G may feel different
• Driving operating a Natural Gas engine is the
  same as diesel
• Remain diligent on maintenance schedule

ISL G Specifications
L Gas Plus Specifications
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ISL G Maintenance Guidelines
Daily Procedures

• Visually inspect the air intake piping and
  radiator hoses for wear points, loose clamps, or
  punctures
• Visually inspect the crankcase breather tube for
  sludge or debris
• Drain oil carryover (CNG) from fuel filter fuel
  filter (Spin-on Type)
• Inspect cooling fan for cracks, loose rivets,
  bent or loose blades
• Check lubricating oil and coolant level
• Throttle Response Test

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ISL G Maintenance Guidelines

• Maintenance Procedures at 500 Hours 7500 Miles
• Lubricating Oil and Filters - Change
• Required Fleetguard oil filter, Part No. LF9009
• Natural gas engine oils must meet Cummins
  Engineering Standard 20074 Recommended Valvoline
  Premium Blue GEO 15W40 (packaging will show
  CES20074 upon it)
• Coolant Filter - Change
• Required Fleetguard filter.
• Use Fleetguard coolant test kit, Part No.
  CC2602, to check the SCA concentration level
• Catalyst Housing - Check
• Check housing for leaks, damage and indications
  of extreme heat
• Charge-Air Cooler - Check
• Visually inspect CAC for dirt and debris blocking
  the fins
• Check for cracks holes and other damages
• Charge-Air Piping - Check
• Supplemental Coolant Additive (SCA) and
  Antifreeze Concentration - Check
• Air Cleaner Restriction - Check

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ISL G Maintenance Guidelines

• Maintenance Procedures at 1000 Hours 15000
  Miles
• Fuel Filter (Spin-on Type) - Change
• Required Fleetguard fuel filter, Part No. NG5900
  
• Overhead Set - Adjust
• Subsequent adjustments to be performed at every
  eighth engine oil change for automotive engines
  or 2000 hours
• Valve lash intake 0.014 in, exhaust 0.030 in
• Drive Belts, Cooling Fan Belt Tensioner, Fan Hub
  (if belt driven), Oxidation Catalyst and Water
  Pump - Check

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ISL G Maintenance Guidelines

• Maintenance Procedures at 1500 Hours 22,500
  Miles

• Spark Plugs (Non Shielded) - Replace
• Use only Cummins Inc. authorized spark plugs,
  Part No. 4955720
• The use of unauthorized parts can affect
  performance and the emission control system.
• The recommended 36,000 km 22,500 mile interval
  is based on an average vehicle speed of 24 kph
  15 mph and must be derated accordingly for
  slower speed applications (i.e. 1500 hr
  multiplied by average kph mph distance
  maintenance interval).
• Ignition Coil (Non Shielded) - Check
• Follow procedure 013-012 (QSOL) using ignition
  coil test kit, Part No. 3164486

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ISL G Maintenance Guidelines
ISL G Maintenance Procedures at 2000 Hours
30,000 Miles

• Air Compressor Carbon Buildup - Check
• Cooling System - Flush
• Overhead Set - Adjust
• Turbocharger - Check
• Vibration Damper, Rubber - Check
• Vibration Damper, Viscous - Check