NOVELTY - A low carbon alcohol diesel oil with high (middle) proportion comprises 50-70 wt.% low carbon alcohol (methanol, ethanol, or their mixture) and 20-45 wt.% diesel oil.    USE - The low carbon alcohol diesel oil with high proportion is used as alternative fuel of internal-combustion engine, and is used for heavy diesel engines with big power, trains, ships, mining machines, and diesel generator set.    ADVANTAGE - The special engine adopts double-fuel system, namely an oil tank for storing fuel methanol (or ethanol) and another oil tank for storing the low carbon alcohol diesel with high (middle) proportion; it can make rich hydrogen by disintegrating and make mixed ester and rich hydrogen by dehydrating. It can shorten the lag period of lightening and the time for lasting burning, improve burning speed and heat efficiency, reduce fuel consumption (when 50% of rich hydrogen substitutes 50% of MH50 methanol diesel, the mass substitution ratio is not greater than 1.2:1), and realize Euro I emission. Because alcohol ester fuel mixed with rich hydrogen can improve burning efficiency greatly without tempering and exploding, the comprehensive effect that mass substitution ratio of methanol fuel is 1.2:1 can be obtained; the low carbon alcohol diesel oil with high proportion takes coalification fuel methanol as fuel, is capable of reducing dependence on petroleum and reducing release of harmful substances when diesel oil burns in the internal-combustion engine, and has remarkable social and economic benefits.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is a special engine adopting double-fuel system, comprising an oil tank for storing fuel methanol (or ethanol) and another oil tank for storing the low carbon alcohol diesel with high (middle) proportion; the fuel methanol (or ethanol) prepares rich hydrogen fuel, dimethyl ether (or diethyl ether) and water by double functional catalyst in the engine; the rich hydrogen fuel is mixed with air in an air inlet channel and enters a cylinder to burn with the low carbon alcohol synchronously; the dimethyl ether (or diethyl ether) are mixed with the fuel methanol (or ethanol) and low carbon alcohol diesel oil to be lightened.