Why vegetable oil?
Comparison b/t SVO and Diesel
Application and usability
Sources of vegetable oil
Advantages of Vegetable Oils
Challenges In Using Vegetable Oils As Diesel Fuels
Scope In India
Pros and Cons
Vegetable oil can be used as an alternative fuel in diesel engines and in
heating oil burners.
When vegetable oil is used directly as a fuel, in either modified or
unmodified equipment, it is referred to as Straight Vegetable Oil
(SVO) or Pure Plant Oil (PPO).
Conventional diesel engines can be modified to help ensure that the
viscosity of the vegetable oil is low enough to allow proper atomization
of the fuel. This prevents incomplete combustion, which would
damage the engine by causing a build-up of carbon.
Straight vegetable oil can also be blended with conventional diesel or
processed into biodiesel or bioliquids for use under a wider range of
Rudolf Diesel was the father of the engine which bears his name. His
first attempts were to design an engine to run on coal dust, but later
designed his engine to run on vegetable oil( fueled by peanut oil).
With idea to make engines more attractive to farmers having a source
of fuel readily available.
Periodic petroleum shortages spurred research into vegetable oil as a
diesel substitute during the 1930s and 1940s, and again in the 1970s and
early 1980s when straight vegetable oil enjoyed its highest level of
The 1970s also saw the formation of the first commercial enterprise to
allow consumers to run straight vegetable oil in their automobiles,
Elsbett of Germany. In the 1990s Bougainvillea conflict, islanders cut
off from oil supplies due to a blockade, used coconut oil to fuel their
5. Why vegetable oil?
India’s demand for diesel fuels is
roughly 6 times that of gasoline.
protecting the global environment and
concerns for long-term energy security,
it becomes necessary to develop
alternative fuels with properties
comparable to conventional fuels.
The crops being used as a fuel actually
suck out the same amount of Carbon
dioxide that they will release when in
fuel form. Almost carbon neutral.
Renewable fuels do not contribute
significantly to Global Warming.
6. Comparison b/t SVO and Diesel
Vegetable oils and their derivatives in diesel engines lead to substantial
reductions in sulphur, carbon monoxide (CO), polycyclic aromatic
hydrocarbons (PAHs), smoke, noise, and particulate emissions.
Contribution of bio-fuels to greenhouse effect is insignificant, since
CO2 emitted during combustion is recycled in the photosynthesis
process in the plants.
Vegetable oils have about 10% lower heating value than diesel due to its
Kinematic viscosity of vegetable oils is higher than that of diesel.
Higher viscosity of vegetable oils (35–45 cSt at 40°C) as against diesel
(3-4 cSt at 40°C) leads to problems in pumping and atomization,
ringsticking, carbon deposits on the piston, cylinder head, ring
grooves, etc. So modifications are required.
8. Application and usability
Modified fuel systems:
With certain modifications, straight vegetable oil (SVO) can be used in
diesel car engines .
Reducing Viscosity and Surface Tension by Preheating, using waste
heat from the engine or electricity, otherwise poor atomization,
incomplete combustion and carbonization may result.
One common solution is to add a heat exchanger and an additional fuel
tank for the petrodiesel or biodiesel blend and to switch between this
additional tank and the main tank of SVO/PPO.
Engine starts on diesel, switched over to warmed vegetable oil then
switched back to diesel shortly before being switched off, to ensure
that no vegetable oil remains in the engine or fuel lines.
9. Vegetable oil blending
High kinematic viscosity of vegetable oils must be reduced to make
them compatible with conventional compression-ignition engines and
Cosolvent blending is a low-cost and easy-to-adapt technology that
reduces viscosity . Blending is done with:
1. diesel fuel
Mixing proportions of the two must be very accurate
An extra fuel tank is also necessary in the vehicle.
Higher rates of wear and failure in fuel pumps and piston rings when
using blends, so this method does not always produce very reliable
Recycled vegetable oil
Used Vegetable Oil (UVO), Waste Vegetable Oil (WVO), Used Cooking
Oil (UCO), or yellow grease (in commodities exchange), is recovered
from businesses and industry that use the oil for cooking.
Utilizing recycled vegetable oil as a replacement for gasoline would
reduce the price of gasoline by preserving the supply of petroleum.
Virgin vegetable oil
Virgin vegetable oil, also termed pure plant oil or straight vegetable oil,
is extracted from plants solely for use as fuel.
Production of vegetable oils for use as fuels is theoretically limited only
by the agricultural capacity of a given economy. However, doing so
detracts from the supply of other uses of pure vegetable oil.
11. Plant types lb/oil acre kg. oil/hectare
Oil Palm 4585 5,000
Coconut 2070 2,260
Jatropha 1460 1,590
Rapeseed 915 1,000
Peanut 815 890
Sunflower 720 800
Safflower 605 655
Soybean 345 375
Hemp 280 305
Corn 135 145
Sources of vegetable oil
There are over 350 different plant types that can supply the oil, here are
Typical oil extraction from 100 kg. of oil seeds:
Castor Seed 36 kg
Copra 62 kg
Cotton Seed 13 kg
Groundnut Kernel 42 kg
Mustard 35 kg
Palm Kernal 36 kg
Palm Fruit 20 kg
Rapeseed 37 kg
Sesame 50 kg
Soyabean 14 kg
Sunflower 32 kg
13. Vehicle suitability
Not all diesel vehicles are suitable to convert to SVO. Diesel vehicles
fitted with most types of rotary pump produced by Lucas, CAV,
Delphi, Stanadyne and Rotodiesel are not recommended for
conversion by Elsbett (Germany) .
Vehicles with common-rail direct injection and unitary direct injection
engine designs cannot be generally converted with ‘one tank’ kits as
they require start up on diesel.
Conversions involving ‘two tank’ kits are required for these vehicles.
16. Advantages of Vegetable Oils
Vegetable oils are locally available resources in rural areas.
Development of bio-fuel industry would strengthen rural agricultural
Biodegradable and non-toxic.
Engine compatible fuel characteristics , used as a diesel substitute with
no/ very little hardware modifications.
Low sulphur content fuels hence environment friendly.
Enhanced fuel lubrication properties.
Lower safety issues involved because of substantially higher flash
points compared to mineral diesel.
Vegetable oils have a reasonable cetane number and hence possess less
Low aromatic content and reduce costly petroleum imports.
17. Challenges In Using Vegetable
Oils As Diesel Fuels
The price of vegetable oil is dependent on the feedstock price.
Feedstock homogeneity, consistency and reliability are questionable.
Homogeneity of the product depends on the supplier, feedstock and
production method used.
Storage and handling is difficult (particularly stability on long-term
Flash point of blends is unreliable.
Compatibility with materials used in IC engine needs to be
Cold weather operation of the engine is not easy with vegetable oils.
Acceptance by engine manufacturers is another major difficulty.
Continuous availability of the vegetable oils needs to be assured before
embarking on the large-scale usage in IC engines.
18. Scope In India
In India, there is a tremendous interest to utilize non-edible vegetable
oils and their derivatives as fuels in diesel engines.
India is producing host of non-edible oils such as Linseed, Castor,
Jatropha, Karanja (Pongamia glabra), Neem (Azadirachta indica),
Palash (Butea monosperma), Kusum (Schlelchera trijuga) etc.
Some of these oils are not being adequately utilized, and it has been
estimated that some plant-based forest derived oils have a much higher
19. Pros and Cons
Renewable: SVO is essentially captured sunlight energy.
Reduces Air Pollution: reduces carbon dioxide emissions.
Increased Range: improves the range of a car.
Come from domestic crop , boosting local economy & supporting
agricultural community .
Cost of Conversion, additional fuel tank.
High Maintenance: find a source of vegetable oil, clog the fuel