What are the categories of biofuel vehicles?

[McReese]

Biofuels refer to fuels extracted from plants that are suitable for internal combustion engines, mainly including bioethanol, biodiesel, ethyl tert-butyl ether, etc. Currently, biofuels primarily consist of ethanol fuel and biodiesel. Ethanol, commonly known as alcohol, is used in ethanol vehicles, which are motor vehicles that use ethanol or ethanol gasoline as their main power fuel. Specific details are as follows: 1. Introduction: Currently, bioethanol fuel has become one of the world's recognized environmentally friendly fuels and a major resource for replacing fossil fuels. Two-thirds of the world's ethanol production and sales are used for fuel. Due to ethanol's properties being relatively similar to gasoline, using ethanol in vehicles can increase the fuel's octane rating, enhance oxygen content, and make combustion in the engine cylinders more complete, thereby reducing harmful emissions. Currently, the use of gasoline-ethanol blended fuel as a substitute for gasoline is becoming increasingly mature in terms of both production and application technology worldwide. 2. There are four fuel application methods for ethanol vehicles: The first is the blending method, where ethanol and gasoline are mixed for use. Since this method does not require significant technical modifications to the internal combustion engine or major vehicle components, it is the primary method for promoting and applying ethanol vehicles. The second is the pure burning method, where only ethanol is used as the main vehicle fuel (E85 or higher). The third is denatured fuel ethanol, which refers to ethanol that is dehydrated and then mixed with denaturants. Denatured fuel ethanol vehicles are still in the experimental application phase. The fourth is flexible fuel, which can use gasoline, ethanol, methanol, or mixtures of these with gasoline, and can also use hydrogen, with the ability to switch between fuels at any time. Currently, apart from the blending method, the other three methods are still in the experimental stage.