Steve Lussier, McNeilus, presented information on the Natural Gas Fleet Applications for Concrete Mixers for our Natural Gas for Transportation Roundtable in Mequon, WI.
3. CNG SYSTEMS - GROWTH
The growth of CNG vehicle adoption has been driven by the cost
differential of diesel fuel vs. natural gas along with the benefits of
“Going Green”- subsidies, tax breaks, marketing, etc.
The Refuse and Mixer industries, due to the nature of their
business, have been at the forefront.
Reasons include:
•Trucks “Return to Base” nightly offer simple time fill fuel solution
•On site fuel station maximizes savings on natural gas costs
•Marketing advantages of Green Technology
•Contract requirements
4. CNG SYSTEMS – BASICS
A typical CNG fuel system is comprised of:
• Storage tanks
• Engine compartment components
• Stainless steel fuel lines
• Fuel Management Module with regulator and high pressure fill ports
CNG is stored at pressures up to 3,600 psi. Fuel
lines are connected to a pressure regulator that
reduces pressure to engine, where a second
regulator controls the engine fuel requirements.
CNG is infused with an odor agent so that leaks
can be identified by smell.
5. Presently there are only two
“gas” engines available for
vocational use installed in new
vehicles.
Both are built by
Cummins/Westport
CNG SYSTEMS - ENGINES
6. CNG SYSTEMS
• Advantages of Compressed Natural Gas (CNG)
– Reduced fuel costs / less price volatility
– Clean engines / simplified exhaust
• Meets 2013 emissions and beyond – no changes in foreseeable future
• No complex after-treatment or diesel exhaust fluid (DEF)
– exhaust consists of simple 3-way catalyst
– American sourced fuel, reduced dependence on foreign oil
– Less driver fatigue with quieter engine
– Use of “green” image in branding
• Operating Pressure
– 3600 PSI at 70°F “nominal fill pressure”
– 110-125 PSI at engine inlet
• Fueling and Range
– Slow fill overnight
– Fill time roughly 10 minutes for fast fill
• Allows for 75-80% of filling capacity (56-60 usable DGE)
– No special training required to fill
– Fuel mileage slightly less than diesel
7. CNG SYSTEMS – DESIGN
• The key consideration in system design is the customers required capacity.
• How much fuel is required per day, per shift etc.
• DGE (diesel gallon equivalent) is the industry standard used to express
capacity
• Tanks are the majority of the expense of the fuel system
• CNG fuel systems are typically mounted behind the cab, on the frame rail,
on the top of the body, and in some cases all of the above.
9. TWIN VERTICAL DESIGN
Pressure Relief Device (PRD)
• Vents CNG tanks at 219°F
(thermal event)
McNeilus MA20 Fuel box
• Fill port (standard NGV1,
optional Transit fill)
• Defuel port
• High and low pressure gauges
• Manual shutoff valve, solenoid
shutoff valve
• Regulator (heated with coolant)
• High pressure filter
• Pressure sensor
CNG Tank
• 76 Diesel Gallon Equivalent (DGE)
total
• Type 4 tank (HDPE liner with
carbon fiber wrap, fiberglass shell)
• 20 year life
Low Pressure Filters
• Two filters supplied by Cummins
CNG Tank Valves
• Contains manual shut-off valve
High Pressure Plumbing
• O-ring face seal and o-ring
boss fittings used on high
pressure plumbing
11. INSPECTIONS AND MAINTENANCE
Ensuring the integrity of your CNG system is a vital part in the safe operation of the natural
gas vehicle. The Federal Code FMVSS 304 requires all on-board CNG fuel systems and
cylinders to be visually inspected for leaks, damage and deterioration after any motor
vehicle accident or fire; and at least every 36 months or 36,000 miles, whichever comes
first.
Typical Maintenance
Inspection every 3 year/36,000 miles
• Must be performed by certified personnel
• Can be performed at most McNeilus service centers
Drain filters
• High pressure filter – 3,000 miles or as needed
• Low pressure filter – weekly/daily (depending on usage)
Spark Plug Changes
• Every 1500 hours
12. CNG CYLINDER TESTING MANDATES
Testing Mandates for NG Storage Vessels
• Bonfire – Container safely vents with pressure relief device
• Drop – Drop tank at different orientations, then pressurize
• Gun fire – No fragmentation
• Burst – Ensure burst above 2.25 times service fill pressure
• Environmental pressure cycle – Pre-condition then cycle for 5,000 cycles at
+135°F, then 5,000 cycles at -40°F
• Pressure cycle – Cycle for 11,250 cycles to 100% service pressure
13. Steve Lussier - Regional Sales Manager
O- 507-374-8631
Ellen Konrad - Sr. Sales Administrator
O- 920-233-9428
THANK YOU