Fuel blends for homogeneous charge compression ignition engines

1. A fuel for a homogeneous charge compression ignition engine, comprising:

(a) a mixture of hydrocarbons, each hydrocarbon in the mixture containing from 4 to 14 carbon atoms;

(b) at least 20 wt. % n-paraffins;

(c) at least 30 wt. % naphthenes;

(d) 20 wt. % or less of aromatic hydrocarbons;

(e) 5 wt. % or less of olefins.

2. The fuel of claim 1 , wherein at least 90 wt. % of the mixture of hydrocarbons consists of hydrocarbons containing from 6 to 10 carbon atoms.

3. The fuel of claim 1 , wherein at least 75 wt. % of the mixture of hydrocarbons consists of hydrocarbons containing from 7 to 9 carbon atoms.

4. The fuel of claim 1 , wherein 15 wt. % or less of the hydrocarbons contain five or fewer carbon atoms.

5. The fuel of claim 1 , wherein the fuel comprises at least 25 wt. % n-paraffins.

6. The fuel of claim 1 , wherein the fuel comprises at least 30 wt. % of n-paraffins.

7. The fuel of claim 1 , wherein the fuel comprises at least 35 wt. % of n-paraffins.

8. The fuel of claim 1 , wherein the fuel comprises at least 35 wt. % naphthenes.

9. The fuel of claim 1 , wherein the fuel comprises 15 wt. % or less of aromatic hydrocarbons.

10. The fuel of claim 1 , wherein the fuel comprises 10 wt. % or less of aromatic hydrocarbons.

11. The fuel of claim 1 , wherein the fuel additionally comprises 3 wt. % or less of olefins.

12. The fuel of claim 1 , wherein the fuel additionally comprises 2 wt. % or less of olefins.

13. The fuel of claim 1 , wherein the fuel additionally comprises 1 wt. % or less of olefins.

14. The fuel of claim 1 , wherein the fuel possesses a dry vapor pressure equivalent of 10 psi (69 kPa) or less.

15. The fuel of claim 1 , wherein the fuel possesses a dry vapor pressure equivalent 8 psi (55 kPa) or less.

16. The fuel of claim 1 , wherein the quantity (wt. %) of naphthenes is greater than the quantity (wt. %) of normal paraffins.

17. A fuel for a homogeneous charge compression ignition engine, comprising:

(a) at least 90 wt. % hydrocarbons containing from six to ten carbon atoms;

(b) at least 20 wt. % normal paraffins;

(c) at least 30 wt. % naphthenes;

(d) 20 wt. % or less of aromatic hydrocarbons;

(e) 3 wt. % or less of olefins.

18. A fuel for a homogeneous charge compression ignition engine possessing a dry vapor pressure equivalent of 8 psi (55 kPa) or less, and comprising:

(a) hydrocarbons containing from 4 to 14 carbon atoms, wherein at least 75 wt. % of the hydrocarbons contain from 7 to 9 carbon atoms;

(b) at least 25 wt. % n-paraffins;

(c) at least 30 wt. % naphthenes;

(d) 15 wt. % or less of aromatic hydrocarbons;

(e) 3 wt. % or less of olefins.