Wheat

Diesel fuel in general is any liquid fuel specifically designed for use in diesel engines, whose fuel ignition takes place, without any spark, as a result of compression of the inlet air mixture and then injection of fuel. Therefore, diesel fuel needs good compression ignition characteristics.

The most common type of diesel fuel is a specific fractional distillate of petroleum fuel oil, but alternatives that are not derived from petroleum, such as biodiesel, biomass to liquid (BTL) or gas to liquid (GTL) diesel, are increasingly being developed and adopted. To distinguish these types, petroleum-derived diesel is increasingly called petrodiesel in some academic circles.

Fuel oil (also known as heavy oil, marine fuel, bunker, furnace oil, or gasoil) is a fraction obtained from petroleum distillation. It includes distillates - the lighter fractions, and residues - the heavier fractions.

The term fuel oil generally includes any liquid fuel that is burned in a furnace or boiler to generate heat, or used in an engine to generate power. However, it doesn't usually include other liquid oils, such as those with a flash point of approximately 42 °C (108 °F), or oils burned in cotton- or wool-wick burners. In a stricter sense, the term fuel oil refers only to the heaviest commercial fuels that crude oil can yield, that is, those fuels heavier than gasoline (petrol) and naphtha.