Section 1-7 - General Information
Fuel
Acceptable and Unacceptable Fuels
1-7-6
1-7-6
9803/3750-05 (1-08-00)
Usage and Effects of Fuels
Note: The information that follows does not indicate types
of fuel that are acceptable or unacceptable.
.
1
Low Sulphur Diesel
In its basic form because of the process of reducing
sulphur by removal of sulphur containing compounds
(which contribute to mechanical lubrication) an
increase in the wear rate of the fuel injection
equipment could occur. In view of this, the major fuel
producers add suitable lubricity improvers to enable
the FIE to run satisfactorily, with no acceleration in
wear rate. They must ensure that the lubricity
improvers do not themselves create residual deposits
that could block the fuel system e.g. filter, injectors
etc.
In addition to the lubrication effect there can also be a
further reduction in the aromatic content of the fuel
which can lead to shrinking/cracking of traditionally
nitrile rubber seals throughout the fuel injection
equipment that has previously been exposed to
higher sulphur level fuels. The major fuel producers
tend to maintain the total aromatic content to an
acceptable level (15% by volume).
2
Ultra Low Sulphur Diesel
Also known as `city diesel'. Available throughout the
UK and some parts of Europe since March 1999. This
fuel has a maximum sulphur content of 0.005% by
weight and a further reduction in the natural lubricity
and aromatic content than experienced with low
sulphur diesel. Major oil producers will add lubrication
improvers and also maintain the total aromatic
content to an acceptable level.
3
Unmodified Vegetable Oils
Burned in diesel engines neat or used as an extender
to mineral derived fuel. When these are subjected to
heat in the fuel injection system they form sticky
deposits that can be found inside the fuel pump and a
hard lacquer in the injectors where exposure to even
higher temperatures takes place.
4
Chemically Modified Vegetable Oils (FAME/VOME)
These fuels have been derived from a wide range of
vegetable oils and animal fats, resulting in better
stability, viscosity and cetane number than those
produced from unmodified vegetable oils, but it is
recognised that there are potential problems
associated with the finished fuel characteristics.
These oils are less stable than mineral oil derived
fuels when stored and they will readily degrade
producing fatty acids, methanol and water, none of
which are desirable in the FIE. These effects are
known to be accelerated when the fuel is stored in the
presence of air and water together.
An extract `common statement' from the FIE
manufactures specifies that "The fuel injection
equipment manufacturers can accept no liability
whatsoever for failure attributable to operating their
products with fuels for which the products were not
designed, and no warranties or representations are
made as to the possible effects of running these
products with such fuels".
The three most common Fame types are RME -
Rapeseed methyl ester (preferred crop in Europe),
SME - Soyabean methyl ester (preferred crop in
USA). Less common FAME's can be derived from
animal fats (e.g. modified beef extracts) and
reclaimed cooking oils.
5
B20 Biodiesel
Biodiesel refers to pure fuel (FAME/VOL) before it is
blended with diesel fuel
. When
biodiesel is blended with diesel fuel it is referred to as
B5, B20 etc., where the number indicates the
percentage of biodiesel in the fuel, for example B5
contains 5% biodiesel.
Biodiesel has different characteristics than mineral
based fuels in that it is able to mix with water and
therefore will have a high water retention capacity -
this could lead to seals swelling, fuel system
corrosion and seal damage.
Biodiesels will `cloud' at higher temperatures than
mineral based fuels. To explain Cloud Point - the
lowest temperature at which fluid can flow and
performs its functions is referred to as Pour Point.
Just prior to reaching its Pour Point the diesel fluid
becomes `cloudy' due to crystallization of waxy
constituents - this is know as Cloud Point. Using
diesel at temperature below its cloud point can result
Summary of Contents for 535-125 Hi Viz
Page 2: ...Section 0 Service Manual 0 0 0 0 9803 3750 05 Notes ProCarManuals com...
Page 4: ...Section 1 General Information 1 0 1 0 9803 3750 05 Notes ProCarManuals com...
Page 6: ...Page No Contents Section 1 General Information 1 ii 1 ii ProCarManuals com...
Page 84: ...Section 2 Care and Safety 2 0 2 0 9803 3750 05 Notes ProCarManuals com...
Page 121: ...Section 3 Routine Maintenance 3 0 3 0 9803 3750 05 Notes ProCarManuals com...
