Process and apparatus for reducing port fuel injector deposits

Claim 1

An improved internal combustion engine fuel delivery system comprising in combination: A. a source of fuel, B. an injector delivering fuel to a combustion chamber within said internal combustion engine, C. a fuel pressure line connecting said source with said injector, D. a fuel pump maintaining said fuel pressure line at a predetermined supraatmospheric pressure during operation of said internal combustion engine, E. a fuel return line through which fuel, which does not enter said injectors, returns from the area of said injectors to said source, said fuel return line operating at a lower pressure than said fuel pressure line during the operation of said internal combustion engine, F. pressure regulating means located within said system for maintaining and controlling the pressure in said fuel pressure line, G. depressurizing means for reducing the pressure below 5 kPa in said fuel pressure line upon ignition cut-off of said internal combustion engine, whereby, upon ignition cut-off, said pressure in said fuel pressure line is reduced.