Diesel Fuel Quality is
a Question Not a Guarantee
(Feature
Article) March 2005
Ground Support Magazine
When it comes to the "acceleration" of diesel fuel quality,
it just doesn't compare to the diesel engines it's supposed
to "rev" up.
Diesel engine designs striving to increase engine
performance have made great advancements in engine fuel
delivery to the combustion chamber. Today's diesel engine is
quieter, smoother and more powerful. But today's diesel
engine owners are overlooking one important factor. The
quality of today's diesel fuel has not advanced at the same
rate as the engine improvements.
Diesel fuel begins to deteriorate as soon as it is produced.
Within 30 days of refining, all diesel fuel regardless of
brand, goes through a natural process called
re-polymerization and oxidation. This process forms
varnishes and insoluble gums in the fuel by causing the
molecules of the fuel to lengthen and bond together. These
components now drop to the bottom of the fuel tank and form
asphaltene also known as diesel sludge. The fuel begins to
turn dark in color, smell bad and in most cases causes
engines to smoke. The engines smoke because some of these
clusters in the early stages are small enough in size to
pass through the engine filtration and into the combustion
chamber. As these clusters increase in size, only part of
the molecule gets burned. The rest goes out the exhaust as
unburned fuel and smoke. With increases in cluster size they
begin to reduce the flow of fuel by clogging filters. The
filters only address the symptom and not the cause.
It is
estimated that eight out of every ten diesel engine failures
have been directly related to contaminated fuel. The
build-up of contaminates in the fuel systems and storage
tanks can quickly clog filters, thus resulting in engine
shut down, fuel pump wear and diesel engine damage.
The
Culprits
Understand that most fuel has some amount of water in it
from either condensation or vents. This threat requires that
we realize the added burden placed upon diesel fuel as
opposed to gasoline. Gasoline acts as a fuel only. Diesel
fuel, on the other hand, also must cool and lubricate
injection system parts. These parts are engineered to very
close tolerances -- up to 0.0002 of an inch -- and any
contamination means rapid part wear. Water displaces the
diesel fuel. When the fuel is displaced wear occurs because
lubrication is now absent.
Water
that enters the combustion chamber results in even more
serious damage. When it comes in contact with the heat of
the combustion chamber (in excess of 2,000 degrees F), it
immediately turns to steam and often explodes the tip of the
injector. Water causes corrosion of tanks, lines, injectors
and greatly reduces combustibility.
Other
areas of concern include the generation of more exhaust
emissions and effecting EPA standards.
Bacteria also presents a serious problem. Bacteria feeds on
nitrogen, sulfur and iron that may be present in the fuel or
tank.
Then
there is algae. There is absolutely no algae in diesel fuel.
You may have fungus and microbial contamination but no
algae. This is a misnomer for diesel sludge. So if you have
a diagnosis of ALGAE and add a biocide, you have done two
things, 1) found a mechanic that is wrong and 2) done
nothing to fix the problem.
What
your engine manufacturers recommends
Your
engine manufacturers recommend that your fuel not be stored
for more than one year and to operate on fuels meeting the
properties of ASTM designation D975 (grades 1-D and 2-D).
If
you have stored fuel or have fuel of questionable age and
have to polish it by an outside service, you may be shocked
at the going rate of "half the price of new" to clean your
fuel. This number can really affect your maintenance budget.
Fuel polishing is the repeated filtering of the entire tank
volume on a regular basis. Turning the entire volume of the
fuel every thirty days is recommended, but most only do it
once in 120 days. Running equipment for an hour that depends
on that fuel is a waste of time. The OEM filtration on an
engine is not intended to process hundreds or thousands of
stored gallons. A fuel management system is required with
the specific capabilities to handle your volume of fuel.
For
more information on this topic refer to:
-
CATERPILLAR (see publication #SEBD 0717-01 Diesel Fuels
and Your Engine)
-
DETROIT DIESEL (see publications Engine Requirements,
Lubricating Oil Fuel, and Filters)
-
JOHN
DEERE (see publication #ISBNO - 86691-143 X)
Why is
there so much bad fuel?
The
number one reason is due to the increased popularity of
diesel power and the accompanying increased demand for more
diesel fuel. There was a time when diesel fuel remained in
the refinery storage tanks long enough to naturally separate
and settle, allowing the clean fuel to be drawn off. Now
with increased demand, diesel fuel never remains stationary
long enough for settling and the suspended water and solids
are passed on to you, the user.
The
change in refinery techniques is another problem. In order
to get more products per dollar; diesel fuel is now being
refined from more marginal portions of the crude oil barrel.
This results in a lower-grade product that is inherently
thicker and contains more contamination.
Finally, current fuel distribution methods also have a
negative impact on the condition of the fuel at the time of
delivery. In many cases, brokers control fuel sales to major
distribution terminals and determine delivery dates. There
is no telling how long that fuel has been in the
distribution network and how many times it has been
transferred. Seldom do these distributors filter the fuel as
they transfer it.
The
solution
On-site storage tanks always have a small amount of the
first gallon of fuel ever put in them, unless it is drained
100 percent and cleaned. So adding new, fresh fuel always
has a bit of the bad added to it every time fuel is
purchased. Diluting the bad with good over time is a losing
battle. The fuel will always be bad fuel until the core
problem is addressed.
The
order of treatment for fuel related problems should always
begin with a determination of whether there is water in the
fuel and if the fuel has microbes (fuel bugs) in it. Water
Paste and Fuel Test Kits can be used for this stage of
maintenance. If microbes are detected, then the use of
biocides is needed. Biocides have no effect on and will not
eliminate the sludge problem. Biocides kill bacteria, that's
all!
The
water issue should always be remedied first by the use of
fuel water separators on the tank or on the equipment. Next
a chemical additive should be added to dissolve diesel
sludge, gums and varnishes that clog filters and injectors.
For long-term prevention, the use of magnet fuel
conditioners is recommended. These devices continually
reverse the re-polymerization of the fuel and reduce the
need for ongoing additive use. These products are offered at
www.dieselcraft.com
There
is no good time to find out that your engine won't operate
or that half its life span is gone prematurely because of
contaminated diesel fuel. A sudden need for diesel fuel
stored to run back up systems and generators can create
another disaster in minutes. Those systems usually run until
bad fuel clogs and "kills" the engine. Ground transportation
equipment and boats can be stranded until the filters are
changed. Or worse, life support and evacuation systems can
quit in commercial buildings, financial institutions,
hospitals and communication facilities. Since no one can
predict an emergency, the only safe method is prevention.
Realize now that you do have a problem and manage it, or
deal with the unexpected catastrophe and reduced equipment
life that comes at the absolutely wrong time and is not in
the budget!
Written by John T. Nightingale President of Dieselcraft
Fluid Engineering,
Auburn
CA
95604
Dieselcraft Fluid Engineering is a manufacturer of diesel
fuel purification products.
www.dieselcraft.com
