ng eng maintenance

8/6/2019 NG Eng Maintenance

http://slidepdf.com/reader/full/ng-eng-maintenance 1/12

CalPacific

Natural Gas Engine

Maintenance

Daniel Polo02.20.09



Over view

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



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



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

LiquefiedN

atural Gas (LN

G)� 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



CNG Considerations

The natural gas compressors must be well

maintained to minimize the migration of oil

around the piston and ring pack, whichcontaminates 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

Oil Carryover from Fueling Station Compressors



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



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

ISL G Maintenance Guidelines

Daily Procedures



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 showCES20074 upon it)

Coolant Filter - Change� Required Fleetguard® filter.

� Use Fleetguard® coolant test kit, Part No. CC2602, to check the SCA concentrationlevel

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





Maintenance Procedures at 1000 Hours [15000

Miles]

Fuel Filter (Spin-on Type) - Change� Required Fleetguard® fuel filter, PartNo. 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



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

Maintenance Procedures at 1500 Hours [22,500 Miles]




Air Compressor Carbon Buildup - Check

Cooling System - Flush Overhead Set - Adjust

Turbocharger - Check

Vibration Damper, Rubber - Check

Vibration Damper, Viscous - Check

ISL G Maintenance Procedures at 2000 Hours [30,000 Miles]


ng eng maintenance

Documents