TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The first multi-component blended fuel is a three-component blended fuel having substantially only a first-component, a second-component, and a third-component; the second known multi-component blended fuel is a two- component fuel used by an existing design of internal combustion engine, the two-component blended fuel having substantially only the first-component and the second-component; and the first three-component blended fuel is produced with a smaller proportion of the first-component than the second known two-component blended fuel, by: blending a first volume of the first-component with: a second volume of the second-component which is the fuel component having a higher stoichiometric air-fuel ratio by mass than the two-component blended fuel; and a third volume of the third-component which is the additional fuel component having a lower stoichiometric airfuel ratio by mass than the two-component blended fuel; and by calculating the second and third volumes such that the stoichiometric air-fuel ratio by mass of the first three-component blended fuel is substantially equal to that of the second known two-component blended fuel. The first multi-component blended fuel is a three-component blended fuel having substantially only a first-component a second- component and a third-component; the second known multi-component blended fuel is a two-component fuel used by an existing design of internal combustion engine, the two-component blended fuel having substantially only the first-component and the second-component; and the first three-component blended fuel is produced with a smaller proportion of the first-component than the two-component blended fuel, by: blending a first volume of the first-component with: a second volume of the second-component, which is the additional fuel component having a greater lower heating value than the two-component blended fuel; and a third volume of the third-component, which is the additional having a lesser lower heating value than the two-component blended fuel; and by calculating the second and third volumes such that the lower heating value of the first three-component blended fuel is substantially equal to that of the second known two-component blended fuel. The first multi-component fuel is a three-component blended fuel having substantially only ethanol, a second-component and a third-component; the second known multi-component fuel is a two-component fuel used by an existing design of an internal combustion engine, the engine having an ethanol sensor used to control operation of the engine, the two-component blended fuel having substantially only ethanol and the second-component, the first three-component blended fuel is produced with a smaller proportion of ethanol than the two-component blended fuel, by: blending a first volume of ethanol with: a second volume of the second-component, which is the fuel component which produces a smaller response when sensed by the ethanol sensor than the two-component blended fuel; and a third volume of the third-component, which is the additional fuel component which produces a larger response when sensed by an ethanol sensor than the two-component blended fuel; and by calculating the second and third volumes such that the response measured by an ethanol sensor to the first three-component blended fuel is substantially equal to that of the second known two-component blended fuel. The first multi-component fuel is a three-component blended fuel having substantially only a first-component, a second-component, and a third-component; the second known multi-component fuel is a two-component fuel used by an existing design of internal combustion engine, the two-component blended fuel having substantially only the first-component and the second- component; the first three-component blended fuel is produced with a smaller proportion of the first-component than the two-component blended fuel; by: blending a first volume of the first-component with: a second volume of the second-component, which is the at least one fuel component having a higher stoichiometric air-fuel ratio by volume than the two-component blended fuel; and a third volume of the third-component, which is the additional fuel component having a lower stoichiometric airfuel ratio by volume than the two-component blended fuel; and by calculating the second and third volumes such that the stoichiometric air-fuel ratio by volume of the first three-component blended fuel is substantially equal to that of the second known two-component blended fuel. The second known multi-component blended fuel substantially comprises only ethanol and gasoline. The known fuel substantially comprises 40-85 (preferably 85) vol.% of ethanol and 60-15 (preferably 15) vol.% of gasoline. In the method, the at least one fuel component common to both the first multi-component fuel and the known multi-component fuel is gasoline. The additional fuel component is an alcohol (preferably methanol or ethanol). The known multi-component blended fuel substantially comprises only methanol and gasoline. The desired value of stoichiometric AFR is equal to the stoichiometric AFR of an existing fuel for use in an existing design of internal combustion engine. In the method of producing a blended fuel, the existing fuel is a two-component blended fuel; the existing fuel is a blend of substantially only ethanol/methanol and gasoline. The blended fuel has a proportion of ethanol less than 85%, and the blended fuel comprises a first volume of ethanol blended with: a second volume of gasoline; and a third volume of the third-component having a lower stoichiometric air-fuel ratio by mass than ethanol (E85), and where: the second and third volumes are calculated such that the stoichiometric air-fuel ratio by mass of the blended fuel is substantially equal to that of E85. EXAMPLE - None given.