System and methodology for purging fuel from a fuel injector during start-up

A method for controlling a fuel system and delivering fuel to an internal combustion engine, the fuel system including at least one fuel injector having at least one capillary flow passage, a heat source arranged along the at least one capillary flow passage, the heat source capable of heating the liquid fuel in the at least one capillary flow passage to a level sufficient to convert at least a portion thereof from the liquid state to a vapor state and at least one intake valve for selectively opening and closing a passageway from said at least one fuel injector to a combustion chamber within said internal combustion engine, the method comprising the steps of:

• (a) determining engine air flow;
• (b) measuring a value indicative of degree of engine warm-up;
• (c) determining a portion of liquid fuel to be converted to the vapor state by the at least one capillary flow passage, said determining step employing the values measured in steps (a)-(b);
• (d) controlling power supplied to the heat source of the at least one fuel injector to achieve a predetermined target temperature, the predetermined target temperature operable to convert the portion of liquid fuel to the vapor state determined in step (c);
• (e) simultaneously with step (d), injecting an initial fuel pulse from said at least one fuel injector while said at least one intake valve is in a substantially closed position.
• (f) upon said heat source achieving said predetermined target temperature, delivering the fuel to a combustion chamber of the internal combustion engine;
• wherein the portion of liquid fuel to be converted to the vapor state is determined to achieve minimal exhaust emissions.

A fuel system for use in an internal combustion engine, comprising:

• (a) a plurality of fuel injectors, each injector including (i) at least one capillary flow passage said at least one capillary flow passage having an inlet end and an outlet end;
• (ii) a heat source arranged along the at least one capillary flow passage, said heat source operable to heat the liquid fuel in said at least one capillary flow passage to a level sufficient to convert at least a portion thereof from the liquid state to a vapor state, and (iii) a valve for metering fuel to the internal combustion engine, the valve located proximate to said outlet end of said at least one capillary flow passage;
• (b) a controller to control the power supplied to said heat source of each of said plurality of fuel injectors to achieve a predetermined target temperature, the predetermined target temperature operable to convert the portion of liquid fuel to the vapor state;
• (c) said controller being operable to inject an initial fuel pulse from said at least one fuel injector while said intake valve is in a substantially closed position prior to the said predetermined target temperature being reached.