US 5,467,754 A · Accumulator fuel injection system

Abstract

A method of reducing undesired premixed burning in an internal combustion engine includes lifting an injector needle of a fuel injector a constant low-lift increment from a valve seat of a valve covers orifice (VCO) nozzle having an injection hole opening into the valve seat, and preventing lifting of the needle beyond the low-lift increment for a sufficient interval of time to inject a relatively small initial fuel charge into the engine from the VCO nozzle, the injection producing a highly atomized, wide-angle spray plume with relatively low penetration. The interval terminates when lifting forces imposed on the needle overcome holding forces imposed on the needle by a stop plate which has opposed first and second surfaces exposed to an ambient fluid pressure and to a fluid vapor pressure, respectively. A subsequent step includes lifting the needle to a higher lift position to inject a main fuel charge into the engine, the main fuel charge being injected as a relatively narrow jet having high penetration. The stop plate preferably has opposed rough and smooth flat surfaces orientable such that preventing step will occur when the smooth surface faces downwardly and will not occur when the plate is inverted such that the rough surface faces downwardly.

Claims31

Dependent claims

A method of reducing undesired premixed burning in an internal combustion engine, comprising:

A. lifting an injector needle of a fuel injector a constant low-lift increment from a valve seat of a valve covers orifice (VCO) nozzle having an injection hole opening into said valve seat;
B. preventing lifting of said injector needle beyond said low-lift increment for a sufficient interval of time to inject a relatively small initial fuel charge into the engine from said VCO nozzle, said injection producing a highly atomized, wide-angle spray plume with relatively low penetration, said interval terminating when lifting forces imposed on said injector needle overcome holding forces imposed on said injector needle by a stop plate, said stop plate having opposed first and second surfaces exposed to an ambient fluid pressure and to a fluid vapor pressure, respectively;
C. lifting said injector needle to a higher lift position to inject a main fuel charge into the engine, said main fuel charge being ejected from said VC0 nozzle as a relatively narrow jet having high penetration.

A fuel injector comprising:

A. an injector body having
(1) a longitudinal bore formed therein,
(2) a valve covers orifice (VCO) nozzle formed in a bottom end of said bore and defining a frusto-conical needle valve seat, and
(3) a pressurized cavity formed therein located above and in communication with an upper end of said bore;
B. an injector needle slidably received in said bore and having a lower frusto-conical needle tip normally seated on said valve seat and an upper end normally disposed proximate a junction between said pressurized cavity and said bore;
and
C. a stop plate disposed in said pressurized cavity and having
(1) an upper surface exposed to an ambient fluid pressure in said pressurized cavity,
(2) a lower surface sealingly contacting a shoulder of said injector body, and
(3) a hole formed therethrough permitting the imposition of forces, generated by said ambient fluid pressure in said pressurized cavity, on said upper end of said injector needle.

7 more elements

Dependencies are inferred from the claim text.

Accumulator fuel injection system

Life of this patent

Accumulator fuel injection system

Life of this patent

Abstract

Claims31