Can bioethanol be used in any vehicle?
Generally, the higher the ethanol component of a gasohol blend, the lower its suitability for standard car engines. Pure ethanol reacts with or dissolves certain rubber and plastic materials and must not be used in unmodified engines. Additionally, pure ethanol has a much higher octane rating than ordinary petrol, requiring changes to the compression ratio or spark timing to obtain maximum benefit. To change a pure-petrol-fueled car into a pure-ethanol-fueled car, larger carburetor jets (about 30-40% larger by area) are needed. Many ethanol engines also need a cold-starting system to ensure sufficient vaporization for temperatures below 13 °C to maximize combustion and minimize uncombusted nonvaporized ethanol. On the other hand, if 10 to 30% ethanol is mixed with fossil petrol, no engine modification is typically needed. Many modern cars can run on these mixtures very reliably. The term “E85” is used for a mixture of 15% (by volume) petrol and 85% ethanol. This mixture has an octane r
