11/10/07
Viewed in the long term and over a broad area, the use of energy
carriers that are produced close to nature, such as rapeseed oil,
leads to lower CO2 emissions than fossil oil. In view of the finite
character of fossil resources, raw materials that can be produced
agriculturally are gaining greater importance. Meeting this trend,
Fendt will be the first tractor manufacturer to introduce a tractor,
the 820 Variogreentec, at the Agritechnica 2007 that runs on rapeseed
oil ex works.
Fendt will be the first tractor manufacturer to introduce a tractor,
the 820 Variogreentec, at the Agritechnica 2007 that runs on rapeseed
oil ex works.
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Integrated in the existing tractor concept
The new concept, which was developed together with the engine
manufacturer Deutz, is based on a valve-controlled two-tank system.
This comprises a 340-litre rapeseed oil tank and a considerably
smaller diesel tank with a capacity of some 80 litres, as well
as sophisticated valve technology. This tank capacity is designed
for 80% rapeseed oil operation, which means that it is above all
for vehicles that are primarily operated at a high engine load.
The engine is first started with diesel fuel and then warmed up.
This is necessary because the rapeseed oil differs significantly
from diesel fuels in viscosity as well as flash point. Both properties
have a decisive influence on combustion. In order to ensure as
complete a combustion process as possible, the vegetable oil must
be sprayed just as finely as the diesel. To achieve this, the viscosity
of the oil must first be adjusted to match that of diesel. The
viscosity of vegetable oil is strongly dependent on temperature:
the higher the temperature is, the lower the viscosity becomes.
That is why the greentec system only switches to rapeseed oil operation
when certain parameters are attained.
The automatic switch-over occurs when the oil has been preheated
to 70 degrees Celsius with the aid of the cooling water heat exchanger
or when engine power output is at least 25 percent of the maximum
load for more than 30 seconds.
As soon as these parameters are no longer met, the system switches
back to diesel operation. The rapeseed oil branch is then flushed
with diesel, which takes a few seconds. Flushing prevents the rapeseed
oil from entering into the diesel. When switching off the engine,
the driver must switch over to diesel operation manually, if the
automatic function has not already done so. The driver can monitor
which fuel is currently being used through a special indicator
in the Varioterminal.
It pays off
This is an integral system, since it was developed together with
the engine manufacturer. The greentec tractor has undergone comprehensive
testing and Fendt gives farmers a manufacturer's guarantee, just
as with the diesel-operated vehicles. Thanks to Fendt's well-known
excellent warranty and goodwill service, owners also have no disadvantages
when selling their tractor on the used machine market.
Benefits that speak for themselves
The single greatest operating cost factor in many farming businesses
is fuel. With the use of rapeseed oil, costs in this area can be
reduced significantly. Because the tax burden on diesel is high,
it is considerably more expensive than rapeseed oil, even when
purchased litre-wise. At oil mills or filling stations, pure rapeseed
oil currently costs about 0.70 euro per litre.
Moreover, rapeseed oil can be manufactured regionally and close
to farms. The path from the producer to the consumer is therefore
accordingly shorter. The by-products of rapeseed oil production – oil
and press cake – can be used as high-grade protein feed for
animal husbandry.
Organic fuels offer a wide range of benefits. A renewable, and
therefore living raw material, though, requires special awareness
of its properties, for example, regarding correct storage.
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