Solenoid operated fuel injector and control valve

A fuel injector responsive to an electrical control signal to both time and meter periodic fuel injections, comprising

• (a) a fuel injector housing containing an injection cavity having an inlet through which each quantity of fuel to be injected is metered and having an outlet through which the metered fuel passes during each subsequent injection period;
• (b) a reciprocating plunger;
• (c) a shuttle piston mounted for reciprocation to increase and decrease the effective size of said injection cavity;
• (d) hydraulic means for controllably linking said shuttle piston to reciprocate with said reciprocating plunger;
• (e) an electrically controlled valve to break the hydraulic link between said reciprocating plunger and said shuttle piston for a selected time at least once during each reciprocation cycle of said plunger to both meter and time said fuel injection on a cycle by cycle basis, said valve including
• (1) a valve housing containing a valve cavity, an inlet passage for connection with a fluid supply, an outlet passage for connection with said hydraulic means and a flow control passage arranged to provide the sole path for fluid communication between said inlet and outlet passage through said valve cavity, said valve housing including a valve seat surrounding said flow control passage;
• (2) a ball positioned within said valve cavity and movable between a closed position in which said ball contacts said valve seat to form a seal capable of preventing back flow from said hydraulic means through said outlet passage to said inlet passage and an open position in which fluid may flow in either direction between said inlet and outlet passages;
• (3) ball biasing means for continuously biasing said ball toward said closed position with a closing force sufficient to maintain said ball in said closed position even when the back pressure drops below the fluid supply pressure;
• and
• (4) operator means for moving said ball between said open and closed positions in response to an electrical control signal in less than one millisecond, wherein said operator means includes
• (a) a stem having a longitudinal axis aligned with the center of said ball and movable between an advanced position in which one end of said stem contacts said ball to move said ball to said open position and a retracted position in which a predetermined gap is formed between said one end of said stem and said ball when said ball is in said closed position to insure full closure of said valve,
• (b) operator biasing means for biasing said stem toward said advanced position with an opening force sufficient to overcome the biasing force imparted to said ball by said ball biasing means, said operator biasing means including a coil compression spring coaxially surrounding said stem, and
• (c) an electromagnetic means for moving said stem from said advanced to said retracted position when electrically energized and for allowing said stem to be moved to said advanced position under the force imparted thereto by said operator biasing means.