Method of reducing the vapor pressure of ethanol-containing motor fuels for spark ignition combustion engines

A reduced vapor pressure hydrocarbon-based motor fuel composition for a conventional internal combustion spark ignition engine comprising a mixture of:

• (a) a hydrocarbon component comprising C3-C12 hydrocarbon fractions;
• (b) a fuel grade ethanol comprising 0.1% to 20% of a total volume of the motor fuel composition;
• (c) an oxygen-containing component comprising at least one of (1) an alkanol having from 3 to 10 carbon atoms;
• (2) a ketone having from 4 to 9 carbon atoms;
• (3) a dialkyl ether having from 6 to 10 carbon atoms;
• (4) an alkyl ester of an alkanoic acid, said alkyl ester having 5 to 8 carbon atoms;
• (5) a hydroxyketone having 4 to 6 carbon atoms;
• (6) a keto ester of an alkanoic acid, said keto ester having 5 to 8 carbon atoms or (7) an oxygen-containing heterocyclic compound having 5 to 8 carbon atoms selected from the group consisting of tetrahydrofurfuryl alcohol, tetrahydrofurfuryl acetate, dimethyltetrahydrofuran, tetramethyltetrahydrofuran, methyl tetrahydropyran, 4-methyl-4-oxytetrahydropyran, and mixtures thereof, and said oxygen-containing additive comprises 0.05% to 15% of the total volume of the motor fuel composition;
• and
• (d) at least one C6-C12 hydrocarbon,
• said motor fuel composition (i) comprising not more than 0.25% by weight of water according to ASTM D 6304 and not more than 7% by weight of oxygen according to ASTM D 4815;
• and (ii) having a ratio between components (b)/{(c)+(d)} from 1:200 up to 200:1 by volume.

A method of making a fuel composition for a modified internal combustion spark ignition engine comprising combining:

• (b) a fuel grade ethanol comprising 0.5% to 99% of a total volume of the motor fuel composition;
• (c) an oxygen-containing component comprising at least one of (1) an alkanol having from 3 to 10 carbon atoms;
• (2) a ketone having from 4 to 9 carbon atoms;
• (3) a dialkyl ether having from 6 to 10 carbon atoms;
• (4) an alkyl ester of an alkanoic acid, said alkyl ester having 5 to 8 carbon atoms;
• (5) a hydroxyketone having 4 to 6 carbon atoms;
• (6) a keto ester of an alkanoic acid, said keto ester having 5 to 8 carbon atoms or (7) an oxygen-containing heterocyclic compound having 5 to 8 carbon atoms selected from the group consisting of tetrahydrofurfuryl alcohol, tetrahydrofurfuryl acetate, dimethyltetrahydrofuran, tetramethyltetrahydrofuran, methyl tetrahydropyran, 4-methyl-4-oxytetrahydropyran, and mixtures thereof, and said oxygen-containing additive comprises 0.5% to 99% of the total volume of the motor fuel composition;
• and
• (d) at least one C6-C12 hydrocarbon,
• so that a ratio between components (b)/{(c)+(d)} is from 1:200 up to 200:1 by volume.