Straight vegetable oil - Definition and Overview

Straight Vegetable Oil (SVO) is a fuel for diesel engines that can be either pure new vegetable oil or WVO (cleaned waste vegetable oil).

SVO burns well in many diesel engines. But due to its relatively high viscosity SVO could lead to poor atomisation of the fuel, incomplete combustion, coking in the injectors (as a hot engine cools), ring carbonisation, and accumulation of fuel in the lubricating oil. This depends on the make of the engines.

Some car engines are suitable for the use of SVO with some modifications. For one solution to use SVO in a car, one needs a tank for vegetable oil and a separate tank of diesel (petrodiesel or biodiesel) to be used during starting and stopping of the engine, and an electric valve that allows transfer to the SVO tank. One also needs to pre-heat the oil or the viscosity will be too high.

In unmodified cars the bad effects can be reduced by mixing vegetable oil with diesel fuel but to be used safely without a special tank and modifications in a petrodiesel engine, vegetable oil must be transesterified to biodiesel.

Some Pacific island nations are using coconut oil as fuel to reduce their expenses and their dependence on imported fuels while helping stabilize the coconut oil market. Coconut oil is only usable where temperatures do not drop below 17 Celsius (62 Fahrenheit).