Fuel compositions with additives
A fuel composition for a spark-ignition internal combustion engine comprises a non-metallic octane-boosting additive. The non-metallic octane-boosting additive is an additive which, when used at a treat rate of 0.67 % by weight, increases the research octane number of a fuel by at least 1.8 whilst maintaining the T 90 and/or the vapour pressure.
1. A fuel composition for a spark-ignition internal combustion engine, the fuel composition comprising a non-metallic octane-boosting additive and a base fuel, wherein the non-metallic octane-boosting additive has the formula:
where:
R 1 is hydrogen;
R 2 , R 3 , R 4 , R 5 , R 11 and R 12 are each independently selected from hydrogen, alkyl, alkoxy, alkoxy-alkyl, secondary amine and tertiary amine groups;
R 6 , R 7 , R 5 and R 9 are each independently selected from hydrogen, alkyl, alkoxy, alkoxy-alkyl, secondary amine and tertiary amine groups;
X is selected from —O— or —NR 10 —, where R 10 is selected from hydrogen and alkyl groups; and
n is 0 or 1,
wherein at least one of R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 11 and R 12 is selected from a group other than hydrogen; and
wherein the non-metallic octane-boosting additive, when used at a treat rate of 0.67% weight additive/weight base fuel, increases the research octane number of a fuel by at least 1.8 without increasing:
the T 90 by more than 2.5%; or
the vapour pressure by more than 2.0%.
2. A fuel composition according to claim 1 , wherein the non-metallic octane-boosting additive, when used at a treat rate of 0.67% weight additive/weight base fuel, increases the research octane number of a fuel by at least 1.8 without increasing:
the T 90 by more than 2.5%; and
the vapour pressure by more than 2.0%.
3. A fuel composition according to claim 1 , wherein the non-metallic octane-boosting additive, when used at a treat rate of 0.67% by weight, increases the research octane number of a fuel by at least 2.5.
4. A fuel composition according to claim 1 , wherein the non-metallic octane-boosting additive, when used at a treat rate of 0.67% by weight, does not increase the T 90 of a fuel by more than 2.0%.
5. A fuel composition according to claim 1 , wherein the non-metallic octane-boosting additive, when used at a treat rate of 0.67% by weight, does not increase the vapour pressure of a fuel by more than 1.0%.
6. A fuel composition according to claim 1 , wherein the fuel composition has a research octane number of at least 80.
7. A fuel composition according to claim 1 , wherein the non-metallic octane-boosting additive has a blending research octane number of greater than 290.
8. A fuel composition according to claim 1 , wherein R 2 , R 3 , R 4 , R 5 , R 11 and R 12 are each independently selected from hydrogen and alkyl groups.
9. A fuel composition according to claim 1 , wherein R 6 , R 7 , R 8 and R 9 are each independently selected from hydrogen, alkyl and alkoxy groups.
10. A fuel composition according to claim 1 , wherein at least one of R 6 , R 7 , R 8 , and R 9 is selected from a group other than hydrogen.
11. A fuel composition according to claim 1 , wherein no more than five of R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 11 and R 12 are selected from a group other than hydrogen.
12. A fuel composition according to claim 1 , wherein at least one of R 2 and R 3 is hydrogen.
13. A fuel composition according to claim 1 , wherein at least one of R 4 , R 5 , R 7 and R 8 is selected from methyl, ethyl, propyl and butyl groups and the remainder of R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 11 and R 12 are hydrogen.
14. A fuel composition according to claim 13 , wherein at least one of R 4 , R 5 , R 7 and R 8 is a methyl group and the remainder of R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 11 and R 12 are hydrogen.
15. A fuel composition according to claim 1 , wherein X is —O— or —NR 10 —, where R 10 is selected from hydrogen, methyl, ethyl, propyl and butyl groups.
16. A fuel composition according to claim 1 , wherein n is 0.
17. A fuel composition according to claim 1 , wherein the additive is selected from:
18. A fuel composition according to claim 1 , wherein the additive is present in the fuel composition an amount of up to 20%.
19. A fuel composition according to claim 1 , wherein ethanol is present in the fuel composition in an amount of up to 85% by volume.
20. A method for increasing the octane number, whilst maintaining the T 90 or the vapour pressure, of a fuel for a spark-ignition internal combustion engine, wherein the method comprises blending a non-metallic octane-boosting additive with the fuel.
21. A fuel composition according to claim 1 , wherein the additive is selected from:
22. A fuel composition according to claim 1 , wherein the additive is a mixture of: