Chevrolet Impala Bi-Fuel (Gasoline/CNG) Supplement (GMNA-Localizing-U.
S/Canada-9087624) - 2016 - CRC - 8/17/15
10 Driving and Operating
Warning (Continued)
gas is ignited. If you suspect a
leak, do not start the engine or
drive the vehicle. Have the
vehicle immediately towed,
inspected, and repaired by an
authorized GM dealer.
Before filling either fuel tank, turn off
the engine.
The gasoline tank is filled through
the standard fill pipe. See “Filling
the Tank” under“Fuel” in the owner
manual.
The CNG fill receptacle is behind
the fuel door on the passenger side
above the gasoline cap.
Refueling Procedure
There are two methods of refueling:
fast fill or time fill. Fast fill is
normally used in fuel stations for
natural gas vehicles. It takes about
two to five minutes to fill up the fuel
tank. Time fill is done with a
refueling appliance, including
residential appliances, or a time-fill
post provided by the fleet operator.
Refueling time varies depending
upon the refueling system used —
consult with the refueling station
attendant or system provider.
Always observe all safety
recommendations and operating
instructions on the refueling
equipment. If a 24 800 kPa
(3,600 psig) nozzle is not available,
a 20 684 kPa (3,000 psig) nozzle
may be connected to the vehicle.
A fuel nozzle less than 7.6 cm (3 in)
long may be difficult to disengage
after dispensing CNG. During fueling, CNG needs to be
delivered to the vehicle at the
appropriate pressure in relationship
to the ambient temperature. This
can be done automatically by a
temperature compensation system
on the CNG fuel dispenser or
manually by stopping the CNG fill at
a recommended pressure related to
the ambient temperature
compensation chart. GM
recommends that customers use
CNG fueling stations that have a
temperature compensation system
whenever possible. Check with the
fuel station. If one is not available,
see the temperature compensation
chart that follows in this section to
choose the appropriate fill pressure
for the ambient temperature. In
addition, fill only to the pressure
level for the lowest ambient
temperature anticipated during
fueling.
Leaving a vehicle connected to a
time fill station can cause the tank
to be filled to a higher pressure than
recommended, especially when
outside temperatures fluctuate.
Disconnect the vehicle from the time
Chevrolet Impala Bi-Fuel (Gasoline/CNG) Supplement (GMNA-Localizing-U.
S/Canada-9087624) - 2016 - CRC - 8/17/15
Driving and Operating 11
fill station as soon as it is full,
unless an auto shutoff feature
is used.
{Warning
If CNG tanks are filled to a higher
pressure than recommended and
then exposed to a much higher
ambient temperature
environment, expansion of the
gas caused by the temperature
change may cause pressure relief
devices on the vehicle CNG
tank(s) to release gas, as
designed. If an ignition source is
present, this could create a risk of
fire or explosion. If there is any
possibility that the tank has been
over pressurized, take steps to
relieve the excess pressure, such
as by driving or running the
vehicle in an outdoor open area
to remove some fuel.Make sure that your CNG vehicle is
properly maintained and repaired to
avoid elevated temperatures
surrounding the tank, since elevated
temperatures in the area of the tank
could also raise the CNG pressure
in the tank.
Consult materials available from
NGVAmerica - http://www.ngvc.org
and the Clean Vehicle
Education Foundation -
http://www.cleanvehicle.org on CNG
fueling stations for more information.
Ambient Temperature / Maximum
CNG Fill Pressure Compensation
Chart
To avoid the risk of fire or explosion
if an ignition source were present,
do not fill above the pressure level
that corresponds to the lowest
ambient temperature expected
during fueling.
Service Pressure 24 800 kPa
(3,600 psig) at 21 °C (70 °F).
