Gm Global Technolgoy Operations, Inc.

John I Deckard

Ernest Bader, Jr

Dan B Kuiper

Robert D Straub

Richard F Teerman

Russell Harmon Bosch

An electromagnetic unit fuel injector for use in a multi-cylinder diesel engine has an externally actuated pump for intensifying the pressure of fuel delivered to a pressure actuated injection valve controlling flow discharge out through a spray outlet and which is normally biased to a closed position by a spring. Pressurized fuel from the pump is also supplied via a throttling orifice to a modulated pressure servo control chamber having a servo piston means operatively associated with the injection valve. A drain passage extends from the servo control chamber with flow therethrough controlled by a solenoid actuated control valve in the form of a poppet valve which is normally biased to a closed position by a valve return spring of predetermined force whereby the control valve is also operative as a pressure relief valve and preferably, a secondary pressure relief valve means is also incorporated into the unit injector so that all of the unit injectors for the engine will operate at a uniform maximum peak pressure.

Electromagnetic unit fuel injector

An electromagnetic unit fuel injector for use in a diesel engine includes a housing with a pump therein defined by an externally actuated plunger reciprocable in a bushing and defining therewith a pump chamber open at one end for the discharge of fuel to a spring biased, pressure actuated fuel injection nozzle. The pump chamber is also connected to a supply/spill chamber via a normally open, hollow, ported valve controlled passage to permit the ingress and egress of fuel, the valve being operated by a solenoid. The stator assembly of the solenoid is fixed to the housing over the supply/spill chamber and has a cover fixed thereto to define an armature chamber for a moveable armature. The solenoid pole piece has a stepped bore therethrough to interconnect the armature chamber and the supply/spill chamber. The armature is operatively connected to the valve by a guide pin slidably and sealingly journaled in a non-magnetic bushing fixed in the stepped bore so that the armature chamber remains dry.

An electromagnetic unit injector for use in a diesel engine includes a housing with a pump therein defined by an externally actuated plunger reciprocable in a bushing to define therewith a pump chamber open at one end for the discharge of fuel via a discharge passage means to a spring biased, pressure actuated injection nozzle. The pump chamber is supplied with fuel from a fuel chamber, containing fuel at a suitable supply pressure, via a one-way valve controlled supply passage. The discharge passage means is also in flow communication with the fuel chamber via a primary drain passage means as controlled by a differential area valve. The differential area valve, at an enlarged diameter end thereof defines, in part, a pressure control valve that is connected by a throttle orifice passage to fuel flow in the discharge passage means and, by a secondary drain passage, having a solenoid actuated control valve therein, to the fuel chamber.

Electromagnetic unit fuel injector with differential valve

An electromagnetic unit fuel injector for use in a diesel engine includes a housing with a pump therein defined by an externally actuated plunger reciprocable in a bushing and defining therewith a pump chamber open at one end for the discharge of fuel to a spring biased, pressure actuated fuel injection nozzle. The pump chamber is also connected to a first chamber via a solenoid actuated, normally open, hollow pressure balanced poppet valve controlled passage to permit the ingress and egress of fuel. The first chamber adjacent to one end of the valve is in flow communication with a second chamber at the opposite end of the valve and these chambers are connected to a drain passage and supply passage, respectively. During a pump stroke, the solenoid can be energized to move the valve in position to block flow from the pump chamber to the first chamber so as to allow the pressurization of fuel by the pump to effect discharge of fuel from the injection nozzle. In a preferred embodiment the solenoid actuated poppet valve is a cartridge type assembly which is adapted to be received in a suitable socket provided for it in the housing and to be secured therein in hydraulic sealed relationship.

Electromagnetic unit fuel injector with cartridge type solenoid actuated

An electromagnetic unit fuel injector for use in a diesel engine includes a housing with a pump therein defined by an externally actuated plunger reciprocable in a bushing and defining therewith a pump chamber open at one end for the discharge of fuel to a spring biased, pressure actuated fuel injection nozzle. The pump chamber is also connected to a spill chamber via a solenoid actuated, normally open, hollow, ported valve controlled passage to permit the ingress and egress of fuel. The spill chamber adjacent to the head end of the valve is in flow communication with a supply chamber at the opposite end of the valve and these chambers are connected to a drain passage and supply passage, respectively and are interconnected to each other by the valve and by a second passage in parallel with the hollow valve. The poppet valve in one embodiment is provided with a pressure assist plunger next adjacent to the head of the valve in the spill chamber so as to be acted upon by spill fuel to effect more rapid opening of the valve. During a pump stroke, the solenoid can be energized to move the valve in position to block flow from the pump chamber to the spill chamber so as to allow the pressurization of fuel by the pump to effect discharge of fuel from the injection nozzle.

An electromagnetic unit fuel injector for use in a diesel engine includes a housing with a pump therein defined by an externally actuated plunger reciprocable in a bushing and defining therewith a pump chamber open at one end for the discharge of fuel to a spring biased, pressure actuated fuel injection nozzle. The pump chamber is also connected to a first chamber via a solenoid actuated, normally open, hollow, ported valve controlled passage to permit the ingress and egress of fuel. The first chamber adjacent to one end of the valve is in flow communication with a second chamber at the opposite end of the valve and these chambers are connected to a drain passage and supply passage, respectively. During a pump stroke, the solenoid can be energized to move the valve in position to block flow from the pump chamber to the first chamber so as to allow the pressurization of fuel by the pump to effect discharge of fuel from the injection nozzle.

An electromagnetic fuel injector nozzle assembly has a pressure balanced poppet valve controlled discharge outlet supplied with pressurized fuel, with a return spring normally maintaining the poppet valve in a closed position. An actuator cylinder means and plunger is incorporated in the nozzle assembly with the actuator plunger positioned therein to engage the poppet valve to effect outward opening movement thereof and has its end of the actuator cylinder means opposite the poppet valve supplied with pressurized fuel for hydraulic actuation of the plunger, while the opposite end of the actuator cylinder means, the end adjacent to the poppet valve, is supplied with pressurized fuel through a flow control throttling orifice and this end of the actuator cylinder is also connected via a modulated pressure passage, having a normally closed solenoid valve therein for controlling flow therethrough, to a low pressure drain passage whereby when the solenoid valve is closed, fluid pressure on opposite ends of the actuator cylinder is substantially balanced whereby to permit seating of the poppet valve by the return spring, and when the solenoid valve is open, a force unbalance will occur across the actuator piston to effect hydraulic unseating of the poppet valve.

Electromagnetic fuel injector nozzle assembly

An electromagnetic unit fuel injector for use in a diesel engine includes a housing with a pump therein defined by a cam actuated plunger reciprocable in a bushing for supplying fuel via a discharge passage in the housing to a spring biased, pressure actuated, injection valve positioned to control flow discharge out through the spray tip outlet at one end of the housing. The discharge passage is also connected to a low pressure, fuel drain passage with flow from the discharge passage, which has a metering orifice passage at one end thereof, to the drain passage being controlled by a normally open, electromagnetic valve. During a pump stroke of the plunger, the electromagnetic valve is energized to thereby block flow from the discharge passage through the metering orifice passage to the low pressure fuel drain passage whereby to allow the pressure of fuel in the discharge passage to increase during the pump stroke of the plunger whereby to effect unseating of the injection valve.

An electromagnetic unit fuel injector for use in a diesel engine includes a pump, in the form of a cam actuated plunger reciprocable in a bushing, to supply fuel at high pressure to a variable volume pressure accumulator chamber and through a flow control orifice to a control chamber in supply flow communication with a fuel injection nozzle assembly having a pressure actuated injection valve controlling the injected charge of fuel from the unit. Flow through the control orifice into the control chamber is selectively controlled by an electromagnetic valve assembly which also selectively controls flow from the control chamber through a drain orifice to a low pressure fuel return or drain line.

An electromagnetic unit fuel injector for use in a diesel engine has a pump including a cam actuated plunger reciprocable in a bushing for intensifying the pressure of fuel delivered to a pressure actuated injection valve controlling flow discharge out through a spray outlet, to a pressure accumulator and, through a throttling orifice passage into one end of a modulation pressure control chamber having a spring biased piston movable therein, the piston engaging one end of the injection valve, this one end of the pressure control chamber downstream of the throttling orifice passage being connected by a conduit, including a solenoid actuated valve controlling flow through a metering orifice to a low pressure fuel drain return line whereby the pressure of fuel in the pressure control chamber acting on the piston is modulated so as to control the seating and unseating of the injection valve.

An electromagnetic unit fuel injector for use in a diesel engine has a pump, provided by a cam actuated plunger reciprocable in a bushing, for intensifying the pressure of fuel delivered to a spring biased closed, pressure actuated injection valve controlling flow discharge out through a spray outlet, to a pressure accumulator and through a throttling orifice passage into one end of a modulation pressure control chamber having an enlarged diameter stem portion of the injection valve therein, the modulation pressure control chamber downstream of the throttling orifice passage being connected by a conduit including a solenoid actuated valve controlling metering orifice with a low pressure fuel drain return line whereby the pressure of fuel in the modulation pressure control chamber acting on the enlarged diameter stem portion of the injection valve is modulated so as to control the seating and unseating of the injection valve.

An electromagnetic fuel injector with a differential pressure actuated injector valve therein to control fuel injection is supplied with fuel at a predetermined supply pressure, the injector having incorporated therein a hydraulic fluid (fuel) powered booster pump means operable to increase the pressure of fuel from the original supply pressure to a higher injection pressure for effecting operation of the injector valve, the flow of hydraulic fluid (fuel) to effect operation of the booster pump means being controlled by a solenoid actuated valve means controlling inlet and discharge of fuel to a fluid control chamber in communication with the power piston of the booster pump through a control or metering orifice of predetermined size, whereby the rate of pressure intensification of fuel to the injector valve is controlled.

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Grand Rapids, MI, United States of America

John I Deckard