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US 4,811,715 AGranted
Electronic unit injector
AssigneeStanadyne, Inc.
InventorsIlija Djordjevic, William W. Kelly, Richard E. Vanderpoel
Life of this patent
Estimating the term…
Abstract
An electronic unit injector employs an expandable chamber which expands as pressure in the injector increases between a pair of threshold pressures. The expansion of the chamber results in a two-phase rate of injection of the injector whereby the initial injection rate is significantly lower than the second injection rate. In one embodiment, the expandable chamber is formed by a pin which is displaceable in a cap mounted to the injector body. The pin bottoms against the cap to define the phase transition.
Claims17
An electronic unit injector comprising:
- injector body means for forming a fuel inlet, an injector chamber and an inlet passage connecting said fuel inlet and said injector chamber;
- nozzle means for defining a nozzle chamber in fluid communication with said injector chamber, discharge orifice means and a valve seat;
- needle valve means including a needle valve mounted in said nozzle means and axially displaceable in response to pressure above a first pre-established threshold in said nozzle chamber from a closed position wherein the needle valve engages the valve seat to prevent the discharge of fuel through said orifice means to an opened position wherein fuel in said nozzle chamber is discharged through said orifice means;
- plunger means including a plunger displaceable in said injector chamber for pressurizing fuel therein;
- expandable chamber means comprising means defining an expandable subtraction chamber in fluid communication with said injector chamber during the pressurization of fuel by said plunger means and means for expanding the volume of said subtraction chamber as the pressure in said subtraction chamber increases between second and third threshold pressures;
- and
- solenoid valve means mounted to said body means and actuable between first and second positions for selectively controlling fluid communication through said inlet passage wherein in the first position fuel communicates from said inlet passage to fill and spill said injector chamber and in a second position fuel communication between said inlet passage and injector chamber is terminated and said plunger is displaceable to pressurize fuel in said injector chamber so that when fuel in said nozzle chamber exceeds said first threshold pressure, fuel is discharged through said discharge orifice means in substantially a two-phase fuel injection rate sequence which is terminated by actuating said solenoid valve means to said first position.
4 more elements
An electronic unit injector comprising:
- injector body means for forming a fuel inlet, an injector chamber and an inlet passage connecting said fuel inlet and said injector chamber;
- nozzle means for defining discharge orifice means, a valve seat and a nozzle chamber in fluid communication with said injector chamber;
- first valve means including a valve member mounted in said nozzle means and axially displaceable in response to pressure above a first pre-established threshold in said nozzle chamber from a closed position wherein the valve member engages the valve seat to prevent the discharge of fuel through said orifice means to an opened position wherein fuel in said nozzle chamber is discharged through said orifice means;
- plunger means for pressurizing fuel in said injector chamber;
- expandable chamber means comprising means defining an expandable subtraction chamber in fluid communication with said injector chamber and means for expanding the volume of said subtraction chamber as the pressure in said injector increases between a second and a third threshold pressure, said expandable chamber means comprising a pin having first and second ends, said first end being exposed to pressure in said subtraction chamber and said pin being displaceable for defining the volume of the subtraction chamber;
- and
- second valve means mounted to said body means for selectively controlling fluid communication through said inlet passage,
- so that as fuel pressurization in said injector chamber increases, the pressure in said subtraction chamber increases and the volume of said subtraction chamber expands until said third threshold pressure is attained whereby pressurized fuel is injected through said discharge orifice means in substantially a two-phase rate of injection sequence wherein the rate of injection of fuel in said first phase is significantly less than the rate of injection of fuel in said second phase, and the attainment of said third threshold pressure generally defines the transition between said first and second phases.
5 more elements
An electronic unit injector comprising:
- injector body means for forming a fuel inlet, an injector chamber and an inlet passage connecting said fuel inlet and said injector chamber;
- nozzle means for defining discharge orifice means, a valve seat and a nozzle chamber in fluid communication with said injector chamber;
- first valve means including a valve member mounted in said nozzle means and axially displaceable in response to pressure above a first pre-established threshold in said nozzle chamber from a closed position wherein the valve member engages the valve seat to prevent the discharge of fuel through said orifice means to an opened position wherein fuel in said nozzle chamber is discharged through said orifice means;
- plunger means for pressurizing fuel in said injector chamber;
- expandable chamber means comprising means defining an expandable subtraction chamber in fluid communication with said injector chamber and means for expanding volume of said subtraction chamber as the pressure in said injector increases between a second and a third threshold pressure, said expandable chamber means comprising a cap mounted to said body means and a pin displaceable in said cap and engageable against said cap to define the third threshold pressure;
- and
- second valve means mounted to said body means for selectively controlling fluid communication through said inlet passage,
- so that as fuel pressurization in said injector chamber increases, the pressure in said subtraction chamber increases and the volume of said subtraction chamber expands until said third threshold pressure is attained whereby pressurized fuel is injected through said discharge orifice means in substantially a two-phase rate of injection sequence wherein the rate of injection of fuel in said first phase is significantly less than the rate of injection of fuel in said second phase, and the attainment of said third threshold pressure generally defines the transition between said first and second phases.
5 more elements
Dependencies are inferred from the claim text.