Tom Shelley reports on the growing move across the Atlantic running diesel cars and pickup trucks on vegetable oils and petrol cars on alcoho
With mineral oil prices high and likely to stay up, it should
come as no surprise that in the land of free enterprise, more and
more diesel car and light truck owners are converting their
vehicles to run on vegetable oils.
The favourite fuel stock at present is waste frying fat from
restaurants, but other sources of supply are being looked at. The
main technical challenge at present is to overcome the higher
viscosity but in the long term, if the idea catches on, there is
a potential conflict between demands for fuel and food for a
still increasing world population.
Sticking to waste vegetable oil, however, is truly 'green' since
otherwise, it presents a disposal problem, and there are other
mineral oil substitute feed stocks which are totally organic
waste derived, which are well worth looking at commercially and
industrially.
We first heard about the move to "Veggie vehicles",
from Walter Darnell of the SMC Corporation of America when we met
him over lunch at a SolidWorks World event.
Walter told us about his friend, who had converted a 2000 VW
Jetta TDI to run on conventional diesel oil until it got hot,
upon which it could be switched to vegetable oil without clogging
up the injectors. Overall mineral diesel oil fuel efficiency was
reported to us as being around 200 to 300 miles per US gallon,
which is significantly smaller than the British Imperial variety.
The next stage, is apparently, to install a pre-heater to avoid
the need for any mineral diesel oil to be used at all.
Dr Rudolf Diesel developed the world's very first diesel engine
to run on vegetable oil in 1895, and when it was demonstrated at
the World Exhibition in Paris in 1900, it was fuelled by peanut
oil.
Complete kits for the two fuel approach are available from
Greasecar, based in Florence, Massachusetts and Frybrid based in
Seattle. Parts for those wishing to devise their own conversions
in the UK are available from C G Engine Services in Reading.
Frybrid points out that the not only must the oil be heated to at
least 70 deg C before it is injected in order to get through the
holes, but the engine must also be hot to avoid oil
polymerisation on metal surfaces leading to carbon build up. The
fuel system also needs to be purged with diesel oil immediately
prior to shutdown.
Elements of he Jetta conversion
The Frybrid System has a vegetable oil fuel tank with a built-in heat exchanger. Heat is supplied from engine coolant which is normally at least 82 deg C. It also employs heated fuel lines, a heated fuel filter and a final fuel heat exchanger. Microprocessor controlled solenoid valves automatically switch to vegetable oil when the proper temperatures have been reached. Pressing a "Purge" button a few seconds before shut down flushes all vegetable oil from the system and replaces it with diesel. When complete, the "Puge mode" indicator goes out and the "Diesel mode" indicator lit. An alarm sounds if the engine is shut down while running in vegetable oil mode and keeps sounding until the engine is re-started unless the purge cycle is completed before shut down. The purge cycle is also automatically initiated if the fuel level goes too low in the vegetable oil tank.
Veggie fuel gauge and purge button on the Jetta
Greasecar says that vegetable oil has superior lubrication and
detergent values over conventional diesel fuel. Examination of
engines is said to show dramatic reductions in carbon build-up.
They also point out that there is no sulphur in vegetable oil and
some studies have shown NOX reductions. Massachusetts gets quite
cold in Winter and Greasecar reports customers using vehicles
daily in temperatures down to -34 deg C. The company recommends
avoiding sources that rinse their fryers with water. Asian food
restaurants are apparently good because they use pure canola or
soy oil, which has a lower gell point and higher quality
restaurants use higher quality oils than fast food outlets.
These technologies are not to be confused with use of biodiesel,
which is made by reacting fat or oil with an alcohol, typically
methanol, in the presence of a catalyst to produce glycerine and
methyl esters, which form the biodiesel. The methanol is charged
in excess to ensure quick conversion and recovered for re-use.
The catalyst is usually sodium or potassium hydroxide.
The other fuel source being looked at with great interest is
wheat and rice straw, which with the help of suitable enzymes,
may be turned into sugars that can be fermented to alcohol. Not
surprisingly, one of the companies most interested in this
possibility is Shell, which has partnered with the Ottawa, Canada
based company Iogen, and has made it clear that it intends to
stay in the fuel and energy business regardless of what happens
to petroleum supplies.
One of the automotive majors committed to bio derived fuels is
Ford. Their Escape Hybrid E85 research vehicle is capable of
running on a hybrid-electric battery, petrol, or a blend of 85
per cent ethanol and 15 per cent petrol. Ford has already put
more than 1.5 million bioethanol capable vehicles on the road
across the world and will produce 250,000 more this year.
Bioethanol did not go on public sale in the UK until March 16th
this year, but can now be found at ten Morrisons supermarkets,
priced cheaper than unleaded petrol from 84.9 p a litre. Five of
the forecourts selling bioethanol are in Somerset where Ford has
sold the most Focus FFVs (Flexible Fuel Vehicles), which can run
on 100 per cent ethanol or 100 per cent petrol or any mix of the
of the two in the same tank.
The remaining bioethanol outlets are in East Anglia, three in
Norfolk and two in Suffolk. Andy Taylor, Ford's European
sustainability director, said: "This is an important
breakthrough for the Ford Focus FFV and the biofuel industry.
Ford has been working with partners such as Morrisons for a year
to make bioethanol publicly available. Together we have taken a
vital next step towards encouraging more customers to consider
buying Ford's biofuel cars."
The 1.8-litre Ford Focus FFV costs from £14,095 - in between the
petrol-only 1.6 and 2.0-litre Focus models.
It is incidentally, perfectly legal to run your car on vegetable
oil, alcohol or almost anything else in the UK, provided you pay
the fuel tax duty.
www.greasecar.com
www.frybrid.com
www.veggiepower.org.uk/main.htm
C G Engine Services
www.biodiesel.org
www.iogen.ca
Pointers
* Diesel engines run perfectly well on waste vegetable oil
provided fuel and engines are sufficiently pre-heated to get over
viscosity and polymerisation problems
* Bioethanol is now on public sale in the UK
* Almost any fuel is legal to use in vehicles in the UK provided
fuel tax is paid.
For more technical developments see www.eurekamagazine.co.uk