Accumulator fuel injection system

A fuel injector for an internal combustion engine comprising:

• A. an injector body;
• B. a nozzle provided on said injector body and defining an injector needle valve seat;
• C. an injector needle slidably received in said injector body and being normally seated on said valve seat;
• and
• D. a stop plate disposed in said injector body and being normally positioned so as to have opposed first and second surfaces thereof exposed to an ambient fluid pressure and to a fluid vapor pressure, respectively.

A fuel injector comprising:

• A. an injector body having
• (1) a longitudinal bore formed therein,
• (2) a nozzle formed in a bottom end of said bore and defining a 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 end 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 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.

In an internal combustion engine accumulator-type fuel injector, a method of reducing undesirable premixed burning in the engine which comprises:

• A. raising an injector needle off its valve seat a small low-lift increment for a sufficient interval of time to inject a small initial fuel charge into the engine;
• B. then lifting the needle to a full lift position to inject the main fuel charge into the engine;
• and
• C. controlling needle lift by controlled venting of pressurized liquid from a pressurized zone located above said needle.