Conventional petrol engines may be adapted to function with ethanol in certain proportions. A flex fuel car can run on petrol, ethanol in the amount of 15% (E15) or 85% (E85). These engines use the same storage system, power and injection regardless of the fuel composition.
Among the advantages of flex fuel car can be found: obtaining fuel (ethanol) from agricultural crops (corn, sugar cane), lower emissions and about the same cost of production to that of a gasoline car. The disadvantages are higher fuel consumption and cold starting problems when using predominant ethanol (E85).
The biodiesel is a form of diesel fuel produced from vegetable oils, animal fats or recycled waste oils. Common blends of biodiesel are: B2 (2% biodiesel, 98% diesel), B5 and B20. B2 and B5 biodiesel fuels can be used without problems in most diesel engines.
Compared with diesel fuel, biodiesel has the following advantages: it can be produced from renewable sources, can be used in any diesel engine, the combustion produces fewer emissions and greenhouse, is biodegradable, non-toxic and handling conditions are less dangerous.
However, compared with diesel a composition fuel 100% biodiesel (B100) has the following limitations: fuel consumption is higher and dynamic performances are lower (about 10% to 2% B100 and B20), the price of production is higher and problems occur with combustion at low temperatures, and reliability of engines may be impaired.
If you thought it would be a good idea to put sunflower, rape or palm oil in your car tank instead of diesel, just to save some money from the price difference between diesel and vegetable oil, you should know what risks expose yourself.
New diesel engines like PD or comonrail with very small modifications are set to run on biodiesel, which is not a crude oil, but a product obtained from oil through certain processes, which results in “methyl ester”. It combines to a certain extent with mineral diesel and is consumed smoothly for the engine.