Heat pipe for heating of gasoline for on-board octane segregation

In an internal combustion engine fuel system having a separator means for separating a primary fuel into a high octane fuel and a low octane fuel and where the primary fuel is heated for separation in the separator, the improvement comprising:

• a heat pipe having an evaporator section positioned to be in the heat exchange relationship with exhaust gas from the internal combustion engine under conditions of use and a heat output area in heat exchange relationship with a primary fuel as it is fed into the separator.

A method for heating a primary fuel for separation into at least a high octane fuel and a low octane fuel in a separator means comprising:

• passing a heated gas stream in thermal communication with an evaporator section of a heat pipe whereby liquid in said section is vaporized and moves to the heat out put section of the heat pipe;
• and
• passing a primary fuel in thermal communication with the heat output section of the heat pipe whereby the fuel is heated and the vaporized liquid in the heat pipe condenser and moves to the vaporizer section.