What does "Bi-Fuel" mean?
In simple terms, Bi-Fuel
can be defined as the simultaneous combustion of two fuels. In the
case of GTI's Bi-Fuel System, natural gas is utilized in conjunction
with diesel fuel to operate the engine. After conversion, the engine
is able to operate on either 100% diesel fuel, or alternately, on
a mixture of diesel fuel and natural gas (or other methane based fuels).
At no time is the engine able to operate on natural gas exclusively.
top
of page
Will my engine have to be modified to operate
on GTI Bi-Fuel?
No. GTI's conversion
technology has been designed to allow for in-field retrofit of diesel
engines without the need to change or modify the design of the engine.
GTI's conversion hardware is mounted externally on the engine and
does not require modification of the engine or alteration of any critical
engine parameter.
top
of page
Will the system affect my engine warranty?
Most OEM engine warranty
programs do not prohibit the use of aftermarket parts or Technologies.
In brief, the policy of OEM's is that they neither recommend nor endorse
aftermarket technologies; however, the use of these products does
not automatically void the validity of the engine warranty. If the
cause is unrelated to Bi-Fuel, the OEM's have historically honored
the warranty and repaired the engine. Additionally, all GTI Bi-Fuel
components that fail within the warranty period will be covered under
the GTI warranty policy.
top
of page
Why can't the engine use 100% natural gas?
Because of the very high
ignition temperature of natural gas (approximately 1300 degrees Fahrenheit),
sufficient heat is not generated during the diesel compression stroke
to ignite 100% natural gas. As such, dedicated gas engines employ
spark plugs and an ignition system to facilitate combustion of the
air-natural gas mixture. In contrast, during Bi-Fuel operation, a
reduced quantity of diesel fuel acts as the ignition source for the
air-gas mixture; this process is often referred to as pilot ignition.
top of page
Will my engine lose power after conversion
to Bi-Fuel?
Under normal circumstances,
engines converted to GTI Bi-Fuel do not suffer any horsepower losses
while operating in Bi-Fuel mode. Because the system maintains OEM
compression ratio values and does not incorporate an air-throttling
device, peak horsepower and efficiency levels of the converted engine
remain on par with 100% diesel operation. In some circumstances, the
engine may be de-rated in Bi-Fuel mode due to shortcomings in gas
supply composition and/or quality.
top
of page
Will my engine run hotter on Bi-Fuel?
GTI's Bi-Fuel technology has been designed to maintain OEM specifications
for all engine temperatures including engine coolant temperature,
oil temperature, exhaust gas temperature and intake air temperature.
The Bi-Fuel System replaces diesel fuel normally consumed by the engine
with an equivalent quantity of natural gas, relative to the heat value
of each fuel. As such, engine air-fuel ratios during Bi-Fuel operation
remain largely an "equivalent gallon" of natural gas is
consumed resulting in similar engine fuel efficiencies. Note:
1 gallon #2 diesel = 140 scf natural gas based on #2 diesel hhv.
top
of page
What about efficiency?
As explained above, GTI's Bi-Fuel System replaces diesel fuel with an equivalent quantity of natural gas. This process results in the same net fuel burn vs. load as would be experienced during 100% diesel operation. For each gallon of diesel fuel displaced during Bi-Fuel operation, there is a corresponding consumption of approximately 140 cubic feet of pipeline quality natural gas (based on 129,000 btu/gallon # 2 diesel & 930 btu/scf natural gas). Thus, for each gallon of diesel fuel displaced during Bi-Fuel operation, an "equivalent gallon" of natural gas is consumed resulting in similar engine fuel efficiencies. Note: 1 d of
natural gas = I liter # 2 diesel.
top
of page
What effect will GTI's System have on
the durability of my engine?
Generally speaking, operation in Bi-Fuel mode has no negative effects
on engine wear rates and durability. As explained above, because engine
thermal loads are equivalent to 100% diesel operation, no excess wear
of combustion chamber components (pistons, rings, valves, injectors,
etc.) occurs. In addition, many users of Bi-Fuel have reported positive
benefits relative to engine wear including extended oil change intervals
and extended time between overhauls. This is primarily the result
of the cleaner burning characteristics of natural gas compared to
diesel fuel.
top
of page
What are the economic benefits to operating
on Bi-Fuel?
Fuel cost savings resulting from operation in Bi-Fuel mode will vary according to the respective cost of each of the fuels. If there is a significant cost differential between the cost of diesel fuel (per gallon, liter, etc.) and the equivalent quantity of natural gas (heat value basis) in favor of the natural gas, significant fuel cost savings would result. The closer the fuels are in price, the lower the fuel cost savings will be during Bi-Fuel mode. In addition to fuel cost savings, engine maintenance savings (as explained above) may also contribute to the economic benefit of Bi-Fuel operation.
top
of page
