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AssigneeRobert Bosch GmbH
InventorsNicola Pacucci, Sisto Luigi De Matthaeis
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The device includes a solenoid valve having a supply conduit communicating with the delivery of the pump, a drain conduit, an electromagnet energizable to control an armature controlling a shutter, and reducing means for reducing disturbance in the delivery pressure of the pump when the electromagnet is energized. The reducing means include a chamber having a predetermined volume and located between the supply conduit and the drain conduit; and a fixed shield having an opening in which slides a small-diameter portion of the stem of the armature. The electromagnet is controlled by an electronic unit via a modulator for modulating the duty cycle of the control pulses, and via a circuit for selecting the frequency of the control pulses on the basis of an estimate of hydraulic disturbances depending on at least one operating parameter.
A device for regulating a delivery pressure of a pump for feeding fuel to an internal combustion engine, the device comprising a solenoid valve having a supply conduit communicating with a delivery conduit of said pump, a drain conduit, a shutter between said supply conduit and said drain conduit, an electromagnet energized variably to control an armature controlling said shutter, a cutoff chamber for cutting off hydraulic pressure between said supply conduit and said drain conduit, said cutoff chamber being of such a volume as to reduce variation in said hydraulic pressure on said armature, wherein said armature comprises a cylindrical stem having a portion housed in said cutoff chamber and connected to said stem by a shoulder, said portion having a diameter smaller than a diameter of said stem to increase the volume of said cutoff chamber, and a fixed shield defining said cutoff chamber and having an opening in which said portion slides so as to eliminate a piston effect of the hydraulic pressure in said chamber on said stem.
A device for regulating a delivery pressure of a pump for feeding fuel to an internal combustion engine, the device comprising a solenoid valve having a supply conduit communicating with a delivery conduit of said pump, a drain conduit, a shutter between said supply conduit and said drain conduit, an electromagnet energized variably to control an armature, said supply conduit having a portion of a predetermined calibrated diameter, said armature being urged by a spring to cause said shutter to close said supply conduit, said electromagnet acting on said armature to variably supplement the urge of said spring, a cutoff chamber for cutting off hydraulic pressure between said supply conduit and said drain conduit, said cutoff chamber being of such a volume as to reduce variation in the hydraulic pressure on said armature, wherein said armature comprises a cylindrical stem having a portion housed in said cutoff chamber and connected to said stem by a shoulder, said portion having a diameter smaller than a diameter of said stem to increase the volume of said cutoff chamber, and wherein a choking element is located removably inside said supply conduit, said choking element having a calibrated hole of a diameter smaller than the calibrated diameter of said portion of the supply conduit, the choking element being selectable from a series of choking elements having calibrated holes of modular diameter to permit modular adjustment of a relevant flow rate.
A device for regulating a delivery pressure of a pump for feeding fuel to an internal combustion engine, the device comprising a solenoid valve having a supply conduit communicating with a delivery conduit of said pump, a drain conduit, a shutter between said supply conduit and said drain conduit, an electromagnet energized variably to control an armature, said armature being urged by a spring to cause said shutter to close said supply conduit, said electromagnet acting on said armature to variably supplement the urge of said spring, a cutoff chamber for cutting off hydraulic pressure between said supply conduit and said drain conduit, said cutoff chamber being of such a volume as to reduce variation in said hydraulic pressure on said armature, wherein said armature comprises a cylindrical stem having a portion housed on said cutoff chamber and connected to said stem by a shoulder, said portion having a diameter smaller than a diameter of said stem to increase the volume of said cutoff chamber, and wherein a choking member is removably located inside said delivery conduit, said choking member having a calibrated hole with a diameter ranging between 0.5 and 0.7 mm, the choking member being selectable from a series of choking members of a modular diameter to permit modular adjustment of a relevant flow rate.
A device for regulating a delivery pressure of a high-pressure pump for feeding fuel to an internal combustion engine, the device comprising a solenoid valve having a supply conduit communicating with a delivery conduit of said pump connected to a common rail for a set of fuel injectors, a drain conduit, a shutter between said supply conduit and said drain conduit, an electromagnet energized variably to control an armature, said electromagnet being controlled by an electronic unit comprising a generator for generating pulses of a predetermined frequency, and a modulator for modulating a duty cycle of said pulses, said armature being urged by a spring to cause said shutter to close said supply conduit, said electromagnet acting on said armature to variably supplement the urge of said spring, a cutoff chamber for cutting off hydraulic pressure between said supply conduit and said drain conduit, said cutoff chamber being of such a volume to reduce variation in said hydraulic pressure on said armature, wherein said armature comprises a cylindrical stem having a portion housed in said cutoff chamber and connected to said stem by a shoulder, said portion having a diameter smaller than a diameter of said stem to increase the volume of said cutoff chamber, and wherein disturbance reducing means are associated with said conduits for reducing a pressure disturbance on said armature.
Dependencies are inferred from the claim text.