•
Always tighten fasteners and fuel connections
to the required torque specification. Overtight-
ening or undertightening could cause leaks.
•
Close the fuel shutoff valve(s) before perform-
ing maintenance and repairs.
•
Do not store a natural gas vehicle indoors for
any extended period of time. Do not bring a
natural gas vehicle indoors unless the work-
shop is equipped with a methane detection and
ventilation system.
In Case of Emergency
If a vehicle has sustained damage or a leak has
been discovered:
1.
Turn the ignition switch off, set the parking brake,
and disconnect the battery.
2.
Remove all ignition sources from the area sur-
rounding the vehicle.
3.
If it is safe to do so, close all fuel shutoff valves.
4.
Open the vehicle doors to introduce fresh air.
5.
Use a natural gas detector to identify leaks in the
fuel system.
Natural Gas Fuel Tank Filling
Procedures
CNG Vehicle Fueling
CNG is moved from the fuel station storage tanks to
the vehicle cylinders through a metered dispenser.
During fueling, as pressure inside of the vehicle cyl-
inders increases, so does the temperature. The dis-
penser shuts off when it determines the CNG cylin-
ders are full.
CNG fuel cylinders cannot be filled to their full capac-
ity of 3600 psi (24 800 kPa) in cooler weather. Since
temperature change causes gas to expand and con-
tract, less pressure in the cylinders on a cold day is
equal to the same amount of gas at a higher pres-
sure on a warm day. The fuel station dispenser has a
temperature-pressure compensating device, which
accounts for ambient temperature during fueling. See
Table 19.1
for approximate full cylinder pressures at
various temperatures.
CNG Temperature/Pressure Compensation Values
Temperature:
°F (°C)
Fill Station Pressure Set Point
3000 psi (20 684
kPa) Set Point
3600 psi (24 821
kPa) Set Point
100 (37.8)
3415 (23 546)
4086 (28 172)
90 (32.2)
3276 (22 587)
3909 (26 952)
80 (26.7)
3138 (21 636)
3754 (25 883)
70 (21.1)
3000 (20 684)
3600 (24 821)
60 (15.6)
2861 (19 726)
3445 (23 752)
50 (10)
2723 (18 774)
3288 (22 670)
40 (4.4)
2584 (17 816)
3131 (21 587)
30 (-1.1)
2446 (16 865)
2973 (20 498)
20 (-6.7)
2307 (15 906)
2814 (19 402)
10 (-12.2)
2169 (14 955)
2655 (18 306)
0 (-17.8)
2031 (14 003)
2495 (17 202)
-10 (-23.3)
1893 (13 052)
2336 (16 106)
-20 (-28.9)
1755 (12 100)
2180 (15 031)
-30 (34.4)
1616 (11 142)
2024 (13 955)
-40 (-40)
1477 (10 184)
1868 (12 879)
Table 19.1, CNG Temperature/Pressure Compensation
Values
Use the following steps to fuel a CNG vehicle.
1.
Shut down the engine and apply the parking
brake.
IMPORTANT: Close all windows and doors dur-
ing the fueling process. Keeping windows and
doors closed allows for easier leak detection
inside the cab after fueling.
WARNING
Natural gas fuel tanks, lines, and valves are al-
ways pressurized. Always observe safety precau-
tions. Failure to do so could lead to loss of con-
trol over a filling hose or to ignition of the natural
gas, which could cause serious bodily injury,
death, or severe property damage.
2.
Ensure all fuel cylinder shutoff valves are open.
See
Fig. 19.1
.
3.
Ensure the vehicle fuel system main shutoff
valve is open.
4.
Open the CNG fuel panel access door and re-
move the dust cap from the vehicle fuel fill port.
Natural Gas Vehicle
19.2
Summary of Contents for 108SD
Page 1: ...Driver s Manual 108SD and 114SD Part Number STI 496 Publication Number STI 496 6...
Page 60: ...7 Climate Control Climate Control Panel 7 1...
Page 65: ...8 Cab Features Cab Amenities 8 1 Mirrors and Windows 8 1...
Page 121: ...15 Drive Axles Differential Lock Drive Axles 15 1 Interaxle Lock Tandem and Tridem Axles 15 2...
Page 125: ...16 Steering System Power Steering System 16 1...
Page 179: ...05 13 2009 f545526 Fig 23 3 Headlight Adjusting Headlight Aiming 23 3...
