Method of blending fuel

Abstract

The present invention relates to a method of blending a multi-component blended fuel. The method comprises selecting as a starting reference a known multi-component blended fuel (e.g. a blend of gasoline and ethanol) which is in use by an internal combustion engine which operates SI or HCCI combustion. The method comprises blending an alternative fuel which can be used by the same engine without modification of the engine, including without modifying the operating regime employed by its engine management system. The alternative fuel is a blend comprising all of the components of the known fuel and an additional fuel component (e.g. methanol). The blend components are blended in proportions which give to the alternative fuel: a stoichiometric air-fuel ratio by mass or by volume substantially equal to that of the known blended fuel; and/or a lower heating valve (e.g. volumetric or gravimetric) substantially equal to that of the known blended fuel; and/or produces a response from an ethanol sensor substantially equal to that of the known blended fuel.

1 . A method of producing a first multi-component blended fuel having at least three fuel components, comprising:
 selecting a second known multi-component blended fuel having at least one fewer fuel component than the first multi-component blended fuel, the second known multi-component blended fuel being in use by an existing design of SI and/or HCCI internal combustion engine;   producing the first multi-component blended fuel by blending together fuel components also found in the known multi-component fuel along with an additional fuel arrangement, wherein:   at least one of the fuel components common to both the first multi-component blended fuel and the known multi-component blended fuel has a stoichiometric air-fuel ratio by mass or by volume higher than the stoichiometric air-fuel ratio by mass or by volume of the second known multi-component blended fuel; and/or has a lower heating value higher than the lower heating value of the second known multi-component blended fuel; and/or produces from an ethanol sensor of the engine a response smaller than the response provided by the second known multi-component blended fuel; and   the additional fuel component: has a stoichiometric air-fuel ratio by mass or by volume lower than the air-fuel ratio by mass or by volume of the second known multi-component blended fuel; and/or has a lower heating value lower than the blended lower heating value of the second known multi-component blended fuel; and/or produces from the ethanol sensor of the engine a response larger than the response produced by the second known multi-component blended fuel; and   the proportions of the said at least one fuel component and the additional fuel component in the first multi-component blended fuel are selected so that: the stoichiometric air-fuel ratio by mass or volume of the first multi-component blended fuel is substantially equal to that of the second known multi-component blended fuel; and/or the lower heating value of the first multi-component fuel is substantially equal to that of the second known multi-component blended fuel; and/or the first multi-component blended fuel produces from the ethanol sensor a response substantially equal to that of the second known multi-component blended fuel.   
     
     
         2 . A method as claimed in  claim 1  wherein:
 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 air-fuel 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. 
 
     
     
         3 . A method as claimed in  claim 1  wherein:
 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. 
 
     
     
         4 . A method as claimed in  claim 1 , wherein:
 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.   
     
     
         5 . A method as claimed in  claim 1  wherein:
 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 air-fuel 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. 
 
     
     
         6 . A method of producing fuel as claimed in any preceding claim, wherein the second known multi-component blended fuel substantially comprises only ethanol and gasoline. 
     
     
         7 . A method of producing fuel as claimed in  claim 6 , wherein the known fuel substantially comprises 40% to 85% ethanol by volume and 60% to 15% gasoline by volume. 
     
     
         8 . A method of producing fuel as claimed in  claim 7 , wherein the known fuel substantially comprises 85% ethanol by volume and 15% gasoline by volume. 
     
     
         9 . A method of producing fuel as claimed in any preceding claim, wherein the at least one fuel component common to both the first multi-component fuel and the known multi-component fuel is gasoline. 
     
     
         10 . A method of producing fuel as claimed in any preceding claim, wherein the additional fuel component is an alcohol. 
     
     
         11 . A method of producing fuel as claimed in  claim 10 , wherein the additional fuel component is methanol. 
     
     
         12 . A method of producing fuel as claimed in any one of  claims 1  to  4 , wherein the known multi-component blended fuel substantially comprises only methanol and gasoline. 
     
     
         13 . A method of producing fuel as claimed in  claim 12 , wherein the known fuel substantially comprises 40% to 85% methanol by volume and 60% to 15% gasoline by volume. 
     
     
         14 . A method of producing fuel as claimed in  claim 13 , wherein the known fuel substantially comprises 85% methanol by volume and 15% gasoline by volume. 
     
     
         15 . A method of producing fuel as claimed in any one of  claims 12  to  14 , wherein the at least one fuel component common to both the first multi-component fuel and the known multi-component fuel is gasoline. 
     
     
         16 . A method of producing fuel as claimed in any one of  claims 12  to  15 , wherein the additional fuel component is an alcohol. 
     
     
         17 . A method of producing fuel as in  claim 16 , wherein the additional fuel component is ethanol. 
     
     
         18 . A blended fuel consisting essentially of ethanol, methanol and gasoline, wherein the proportion of each of ethanol, methanol and gasoline is selected so as to provide the same stoichiometric air-fuel ratio by mass, the same stoichiometric air-fuel ratio by volume, the same lower heating value and/or the same measurement on an ethanol fuel sensor, as a fuel consisting of 85% ethanol by volume and 15% gasoline by volume. 
     
     
         19 . A blended fuel comprising substantially only ethanol, gasoline, and a third component, for use in an internal combustion engine configured to run on E85, wherein: 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 E85,   and wherein:   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.   
     
     
         20 . A method of producing a three-component blended fuel having substantially only a first component, a second component, and a third component,
 wherein the three-component blended fuel has a desired proportion of the first component and a stoichiometric AFR by mass equal to a desired value,   the method comprising blending a first volume of the first component with:   a second volume of the second component having a higher stoichiometric air-fuel ratio by mass than the desired value; and   a third volume of the third component having a lower stoichiometric air-fuel ratio by mass than the desired value,   
       to thereby produce the three-component blended fuel. 
     
     
         21 . A method of producing a blended fuel having a plurality of fuel components, comprising blending selected volumes of each fuel component to thereby produce the blended fuel, wherein:
 at least one fuel component has a higher stoichiometric air-fuel ratio by mass than the two-component blended fuel;   at least one fuel component has a lower stoichiometric air-fuel ratio by mass than the two-component blended fuel; and   the volumes of each component are selected such that the stoichiometric air-fuel ratio by mass of the blended fuel is substantially equal to a desired value of stoichiometric AFR.   
     
     
         22 . A method of producing a blended fuel as in  claim 21 , wherein 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. 
     
     
         23 . A method of producing a blended fuel as in  claim 22 , wherein the existing fuel is a two-component blended fuel. 
     
     
         24 . A method of producing a blended fuel as in  claim 23 , wherein the existing fuel is a blend of substantially only ethanol and gasoline. 
     
     
         25 . A method of producing a blended fuel as in  claim 23 , wherein the existing fuel is a blend of substantially only methanol and gasoline.