1. ROADWAY MHLF: WINTER FUELLING
OCTOBER 2014 ROADWAY 45
A
long with their daily
responsibilities of running a
safe, efficient and compliant
fleet, many transport managers will
have to play the role of amateur
weather forecaster in order to
estimate their requirement for
de-icer, rock salt and soup for the
vending machine. How many also
wonder how their fuel supply will
cope with the all too imminent drop
in temperature?
You may already have an
established winter fuel additive
formulation in place with your
diesel supplier, but now might be a
good time to revisit and review this
important requirement.
The main winter operability issue
is the waxing of diesel at lower
temperatures. It can solidify into
a cloudy, partially crystalline state
to create that familiar challenge.
Below the temperature at which this
begins to occur – cloud point – fuel
filters and lines may clog creating
the telltale symptoms of fuel
starvation. In the UK the summer
diesel cloud point of EN590 road
diesel fuel is around 3°C. Winter
diesel is around -5°C.
There is also growing concern
about the negative effects of
water and diesel bug since the
introduction of biodiesel.
A couple of tests will let you
know how well your fuel is
performing. Cold Filter Plugging
Point (CFPP) measures the rate at
which diesel fuel flows through a
standard filtration device, within
a specified time, as it is cooled
under controlled conditions. ASTM
D4539 is designed to measure the
performance of diesel with its winter
additives.
There are a number of solutions
which allow diesel engines to
continue to operate in cold weather
conditions.
Fuel preheater
Electric heaters are often retrofitted
to commercial vehicles to warm fuel
tanks and so keep diesel moving
when temperatures drop. This
is because heaters do not deal
with the leftover diesel in the fuel
feed system. Modern common-
rail engines may survive milder
conditions without such a heater as,
even when external temperatures
are below CFPP, the return pipe
delivers a stream of warmed fuel
to the tank. Though heaters and
the heat from common-rail return
pipes can be extremely effective for
keeping vehicles moving, starting
may still be an issue without the
help of winter additives.
Winter fuel classes
Today waxing is a relatively rare
occurrence in the UK, except
in unusually severe conditions,
since EN590 (standard fuel station
diesel) must meet standard CFPP
characteristics, usually achieved
by a tailored combination of
additives. EN 590 has six classes
from A to F to meet climactic
conditions throughout Europe.
Central and Western Europe winter
diesel (Winterdiesel, diesel d’hiver)
must meet Class F conditions –
CFPP = -20°C) at least from the
beginning of December to the end
of February. During a transitional
period (mostly October and April), a
lower class must be met.
Additional precautions
The moister winter air, drawn in
by tanks as they breathe, will add
to the water burden, along with
the inevitable condensation which
forms as the thermometer rises
and falls. Although you may think
that colder weather will prevent
bug growth, when combined with
biodiesel, this additional water is
likely to create ideal conditions
for that growth. Regular water
draining, de-emulsification agents
plus testing are the ideal way to
minimise risk and catch problems
early enough to avoid expensive
damage and downtime.
Water detection tests will help
to identify when water is gathering
at the bottom of the tank and
readily available diesel test kits can
quickly and easily detect the level
of diesel bug present in the tank,
putting you in control. As an added
precaution, Conidia Bioscience
recommends introducing a pre-
upload test for each fuel delivery
which, for example only takes
10 minutes using its FUELSTAT
test kit, to avoid taking on heavily
contaminated diesel.
Now is the perfect time of
year to be re-assessing your fuel
specifications and maintenance
regimes, so everything keeps
moving during those cold winter
months.
Keeping winter bugs at bay
David Armitage of Surrey-based fuel testing organisation Conidia Bioscience warns
that, as preparations begin for another winter, spare a thought for your fuel and tanks
Below: A
pre-upload test
is recommended
for each fuel
delivery to avoid
taking on
contaminated
diesel. Conidia
Bioscience’s
FUELSTAT test
kit takes about
10 minutes