A process for making a fuel for a homogeneous charge compression ignition engine, the process comprising blending hydrocarbons to produce a fuel mixture that comprises: (a) a mixture of hydrocarbons, each hydrocarbon in the mixture comprising from 4 to 14 carbon atoms, wherein at least 75 wt. % of the hydrocarbons in the fuel mixture comprise from 7 to 9 carbon atoms; (b) at least 20 wt. % of n-paraffins; (c) at least 30 wt. % of napthenic hydrocarbons; (d) 20 wt. % or less of aromatic hydrocarbons; (e) a dry vapor pressure of 10 psi (69 kPa) or less as measured by method ASTM-D5191 at 37.8°C, wherein the fuel mixture possesses a Power Index that is greater than or equal to 2 when the fuel mixture is combusted in a homogeneous charge compression engine, the Power Index being defined by the equation: Power Index = ARE Ax ∗ MIMEPx / AREAy ∗ MIMEPy wherein MIMEP is defined as the maximum indicated mean effective pressure achieved inside a homogeneous charge compression ignition engine cylinder during combustion of the fuel mixture (x) or the reference fuel (y), respectively, and an equivalent mass of both fuel mixtures is combusted, wherein y is a reference fuel comprising 11 wt. % n-heptane, 37 wt. % iso-octane, 32 wt. % toluene, 11 wt. % methyl-cyclohexane and 9 wt. % 1-hexene, wherein AREAx and AREAy are defined as distinct areas on a graph of load (indicated mean effective pressure, or IMEP) versus engine revolutions per minute for the fuel mixture (x) and the reference fuel (y), respectively, each distinct area having an upper bound at the maximum IMEP during combustion of each fuel at an RPM ranging from 1500RPM to 2500RPM, and having a lower boundary at the IMEP below which combustion of each fuel becomes unstable at an engine RPM ranging from 1500RPM to 2500RPM. (a) a mixture of hydrocarbons, each hydrocarbon in the mixture comprising from 4 to 14 carbon atoms, wherein at least 75 wt. % of the hydrocarbons in the fuel mixture comprise from 7 to 9 carbon atoms; (b) at least 20 wt. % of n-paraffins; (c) at least 30 wt. % of napthenic hydrocarbons; (d) 20 wt. % or less of aromatic hydrocarbons; (e) a dry vapor pressure of 10 psi (69 kPa) or less as measured by method ASTM-D5191 at 37.8°C, wherein the fuel mixture possesses a Power Index that is greater than or equal to 2 when the fuel mixture is combusted in a homogeneous charge compression engine, the Power Index being defined by the equation: Power Index = ARE Ax ∗ MIMEPx / AREAy ∗ MIMEPy wherein MIMEP is defined as the maximum indicated mean effective pressure achieved inside a homogeneous charge compression ignition engine cylinder during combustion of the fuel mixture (x) or the reference fuel (y), respectively, and an equivalent mass of both fuel mixtures is combusted, wherein y is a reference fuel comprising 11 wt. % n-heptane, 37 wt. % iso-octane, 32 wt. % toluene, 11 wt. % methyl-cyclohexane and 9 wt. % 1-hexene, wherein AREAx and AREAy are defined as distinct areas on a graph of load (indicated mean effective pressure, or IMEP) versus engine revolutions per minute for the fuel mixture (x) and the reference fuel (y), respectively, each distinct area having an upper bound at the maximum IMEP during combustion of each fuel at an RPM ranging from 1500RPM to 2500RPM, and having a lower boundary at the IMEP below which combustion of each fuel becomes unstable at an engine RPM ranging from 1500RPM to 2500RPM. wherein MIMEP is defined as the maximum indicated mean effective pressure achieved inside a homogeneous charge compression ignition engine cylinder during combustion of the fuel mixture (x) or the reference fuel (y), respectively, and an equivalent mass of both fuel mixtures is combusted, wherein y is a reference fuel comprising 11 wt. % n-heptane, 37 wt. % iso-octane, 32 wt. % toluene, 11 wt. % methyl-cyclohexane and 9 wt. % 1-hexene, wherein AREAx and AREAy are defined as distinct areas on a graph of load (indicated mean effective pressure, or IMEP) versus engine revolutions per minute for the fuel mixture (x) and the reference fuel (y), respectively, each distinct area having an upper bound at the maximum IMEP during combustion of each fuel at an RPM ranging from 1500RPM to 2500RPM, and having a lower boundary at the IMEP below which combustion of each fuel becomes unstable at an engine RPM ranging from 1500RPM to 2500RPM.