From:  www.cummins.com  (Customer Assistance>FAQ>General)

What is Cummins' position on the use of Biodiesel fuel in Cummins engines?

Background

With increased interest in emissions and reducing the use of petroleum
distillate based fuels, some governments and regulating bodies are
encouraging the use of bio fuels. Biodiesel fuels should be considered
experimental at this time. Governmental incentives and/or environmental
legislation to use bio fuels may have an impact on the sales and use of
Cummins engines. This document outlines Cummins criteria and parameters when
using biodiesel fuel. SME or SOME 'Soy Methyl Ester' Diesel is the most
common bio diesel in the U.S. and is derived from soybean oil. Soy Diesel is
a biodiesel/petrodiesel blend based on SME. RME 'Rape Methyl Ester' Diesel
is the most common biodiesel in Europe and is derived from rapeseed oil.
These fuels are collectively known as Fatty Acid Methyl Esters (FAME).

Fuel Characteristics

Biodiesel fuels are methyl/ethyl ester-based oxygenates derived from a broad
variety of renewable sources such as vegetable oils, animal fats, and
cooking oils. Their properties are similar to diesel fuel, as opposed to
gasoline or gaseous fuels, and thus are capable of being used in compression
ignition engines. Biodiesel fuels have a lower energy content; about 89% of
#2 diesel fuel, and is therefore a less efficient fuel. Its higher viscosity
range (1.9-6.0 centistokes) vs 1.3-5.8 centistokes for diesel) helps offset
the lower energy content through reduced barrel/plunger leakage resulting in
slightly improved injection efficiency. Combining lower energy content and
slightly improved injection efficiency, biodiesel fuel provides 5-7% less
energy per gallon compared to diesel fuel. The cetane value of biodiesel
fuel is 40 minimum compared to 42 minimum for Cummins diesel fuel
specification. Biodiesel fuel has improved lubricity compared to standard
diesel fuel. There are provisional specifications for FAME issued in Germany
under DIN V 51 606, and also recently through ASTM PS-121, however these
standards are under development and are subject to change. For additional
information, refer to the Cummins diesel fuel specifications listed in Table
1 and to the ASTM provisional specification PS-121 for biodiesel fuels.

Emissions

It is the responsibility of the user to obtain the proper local, regional,
and/or national exemptions required for the use of biodiesel in any
emissions regulated Cummins engine. From the Comprehensive Health and
Environmental Effects testing, a fuel blend consisting of 20% biodiesel and
80% diesel fuel (B20) can yield percent reductions ranging from 16-33% in
particulates, 11-25% in Carbon Monoxide (CO), and 19-32% in Hydrocarbon (HC)
emissions. The B20 biodiesel fuel blend will cause an increase in NOx of 2%.

Performance and Durability Results

Cummins test data on the operating effects of biodiesel fuels indicates that
typically smoke, power, and fuel economy are all reduced. However, as there
are no firm industry standards on the content and properties for bio fuels,
consistency and predictability of biodiesel operation is not well
documented. Biodiesel provides approximately 5-7% less energy per gallon of
fuel when compared to distillate fuels. To avoid engine problems when the
engine is converted back to 100% distillate diesel fuel, do not change the
engine rating to compensate for the power loss when operated with biodiesel
fuels. Elastomer compatibility with bio diesel is still being monitored. The
condition of seals, hoses, gaskets, and wire coatings should be monitored
regularly. Cummins certifies its engines using the prescribed EPA and
European Certification Fuels. Cummins does not certify engines on any other
fuel. It is the user's responsibility to use the correct fuel as recommended
by the manufacturer and allowed by EPA or other local regulatory agencies.
In the United States, the EPA allows use of only registered fuels for
on-highway applications. The EPA has additional alternative fuel information
at: http://www.epa.gov/otaq/consumer/fuels/altfuels/altfuels.htm Given the
current industry understanding of bio fuels and blending with quality diesel
fuel, it would be expected that blending up to a 5% volume concentration
should not cause serious problems. For customers intent on blending bio
fuels above a 5% volume concentration, the following concerns represent what
is currently known in the industry. Concentrations beyond 5% by volume could
have an adverse effect on the engine's performance and the fuel system
integrity/durability. The affects are more serious with increasing
concentration levels. Areas of concern when operating with biodiesel fuels
include low temperature operability (fuel gelation, filter plugging), heat
content (poor fuel economy), and storage and thermal stability (filter
plugging, injector deposits). The oil change interval can be affected by the
use of biodiesel fuels and some applications may require shortening
intervals to half of the diesel equivalent. Lube oil dilution in
applications with significant part load operation will fall under this
guideline. In addition, from Cummins' fuel systems suppliers, the following
issues are also noted: swelling and hardening/cracking of some elastomer
seals within the fuel system/engine, corrosion of fuel system and engine
hardware - especially aluminum and zinc, solid particle blockage of fuel
nozzles and passages, filter plugging, injector coking, higher injection
pressures due to physical flow properties - reduced fuel system life, added
stress and heat to injection components - especially rotary fuel pumps -
increased pump seizures and early life failures, poor fuel spray
atomization - reduced fuel economy. Pure biodiesel fuel is not stable and
its acid content increases over time, which can damage powder metal
components.

Fuel System Vehicle Issues and Storage

The oil change interval can be affected by the use of biodiesel fuel. End
users are advised to use oil sampling to monitor the engine oil condition
and to determine the optimum oil change interval. Pure biodiesel fuel can
cause a chemical reaction with lube oil resulting in oil sludging. Elastomer
compatibility with biodiesel is still being monitored. The condition of
seals, hoses, gaskets, and wire coatings should be monitored regularly.
Biodiesel fuels contain residual alcohol from the esterification process,
which can remove deposits from fuel tanks and lines causing filter plugging
during initial testing. The fuel system should be flushed with this fuel
before operation, and the fuel filters will need frequent replacement in the
early stages of operation in older units. Biodiesel fuels may pose low
ambient temperature problems for both storage and operation. At low ambient
temperatures, fuel may need to be stored in a heated building or a heated
storage tank. The fuel system may require heated fuel lines, filters, and
tanks. Filters may plug and fuel in the tank may solidify at low ambient
temperatures if precautions are not taken. Consult your bio diesel supplier
for assistance in the blending and attainment of the proper cloud point
fuel. Biodiesel has poor oxidation stability, which can result in long term
storage problems. The poor oxidation stability qualities may accelerate fuel
oxidation in the fuel system. This is especially true in engines with
electronic fuel systems because they operate at higher temperatures. Consult
the fuel supplier for oxidation stability additives. Biodiesel fuel is an
excellent medium for microbial growth. Microbes cause fuel system corrosion
and premature filter plugging. The effectiveness of conventional
anti-microbial additives, when used in biodiesel is not known. Consult your
fuel and additive supplier for assistance. Care must be taken to remove
water from fuel tanks. Water accelerates microbial growth. Water is
naturally more prevalent in biodiesel fuels than in distillate fuels.

Warranty and the use of Biodiesel Fuel in Cummins Engines

Cummins neither approves or disapproves of the use of biodiesel fuel.
Cummins is not in a position to evaluate the many variations of biodiesel
fuels or other additives, and their long-term effects on performance,
durability or emissions compliance of Cummins products. The use of biodiesel
fuel does not affect Cummins Material and Workmanship warranty. Failures
caused by the use of biodiesel fuels or other fuel additives are NOT defects
of workmanship and/or material as supplied by Cummins Inc. and CANNOT be
compensated under the Cummins' warranty. Bosch states in their Diesel Fuel
Quality -- Common Position Paper (03/05/99) that no guarantee on FIE is
given so far to any alternative fuel except for Diesel + 5% FAME. There is a
major difference between operating on pure (100% concentration) biodiesel
fuels and biodiesel/petro diesel fuel blends.

Another interesting article:

Cummins B5 Biodiesel Capability for Dodge Ram Pickup on Display for Visit of
President Bush to Biodiesel Refinery

For Immediate Release
May 17, 2005

COLUMBUS, Ind. - Environmental progress achieved by Cummins Inc.(NYSE:CMI)
was displayed yesterday as part of a visit by President Bush to the Virginia
Biodiesel Refinery in West Point, Virginia.  A Cummins-powered Dodge Ram
pickup truck with a full tank of B5 biodiesel featured as part of the
display at the Refinery to highlight to the President the increasing
availability of B5 biodiesel-capable vehicles.

"President Bush and his administration are making an important contribution
to promoting the wider use of both diesel and biodiesel fuel," said
Christine Vujovich, Cummins Vice President - Marketing and Environmental
Policy.  "The increased use of diesel engines will help to reduce the
nation's dependency on imported oil and enhance our energy security.  At the
same time, the use of biodiesel will bring economic opportunities to
America's farmers."

Use of B5 biodiesel will further enhance the credentials of the latest
Cummins 610 Turbo Diesel in the Dodge Ram pickup truck. With 610 lb-ft of
torque available and 325 hp rated power,  the Cummins engine has more
performance than other comparable diesels for customers who demand durable
and dependable power.

Jeff Caldwell, Cummins Executive Director - DaimlerChrysler Business,
commented, "The option of running the Cummins 610 Turbo Diesel with B5
biodiesel in the Dodge Ram will be seen as a significant step forward in
encouraging greater use of renewable fuel.   This is a popular engine - last
year Cummins produced over 150,000 of the 610 Turbo Diesel engines for
DaimlerChrysler who manufactures the Dodge Ram.  DaimlerChrysler is to be
commended for taking a leading role in helping the nation to reduce its
dependency on imported oil."

Pure biodiesel is a natural substance derived from soybean and other oil
seed crops grown in the U.S. which is both biodegradable and environmentally
sustainable.  B5 biodiesel is a fuel blend of 5 percent pure biodiesel with
95 percent standard petroleum diesel, and is the most commonly acceptable
specification for heavy-duty engines. The use of biodiesel has grown
dramatically from just 500,000 gallons in 1999 to 30 million gallons in
2004.  Estimates now anticipate an annual demand of 5 billion gallons by
2012 for renewable fuels, including both biodiesel and ethanol in North
America.

Sorry, it was Nosey who posted the Cummins response.

Also, my friends did point out that biodiesel is not good for winter in
cold climates but you should still run a min of 2% for lubricity.

And I think reducing our dependance on foreign oil is always a good
thing.

Charles