Controlled nozzle injection method and apparatus

A nozzle injection apparatus for use in internal combustion engines, said apparatus comprising:

• a fuel pump for intermittently pressurizing fuel;
• a leakless fuel injection nozzle;
• an injection conduit in fluid communication with said fuel pump, said injection conduit permitting said pressurized fuel to be communicated to the leakless fuel injection nozzle;
• a residual pressure gallery in fluid communication with said fuel pump and said nozzle;
• a spring-biased first ball valve assembly for controlling the passage of pressurized fuel from said fuel pump to said nozzle, said first ball valve assembly being controllable between a first state in which a ball of said first ball valve assembly is biased against a corresponding seat, and a second state in which said ball is lifted off said seat against the force of said spring bias;
• a second ball valve assembly for controlling the passage of residual pressurized fuel from said injection conduit to said residual pressure gallery, said second ball valve assembly being controllable from a first state in which a ball of said second ball valve assembly is biased against a corresponding seat to prevent the passage of pressurized fuel from said injection conduit to said residual pressure gallery, and a second position in which said ball is not in contact with said ball valve seat to permit the passage of pressurized fuel from said injection conduit to said residual pressure gallery;
• and
• a piston in operative communication with said ball of said second ball valve assembly, said piston being movable between a lowered position and a raised position upon pressurization of said fuel by said fuel pump;
• wherein when in said raised position said piston forces said ball of said second ball valve assembly against its corresponding seat to prevent backflow of said pressurized fuel;
• wherein said piston moves from said raised position to said lowered position when pressure in a pumping chamber of said fuel pump is lowered;
• and
• wherein when said piston in lowered, said ball of said second ball valve assembly retracts from its corresponding seat to permit excess pressure in said injection conduit to flow past said ball to bring the line pressure down to a pressure level in said residual pressure gallery.