Patent application number | Description | Published |
20080257989 | Fuel Injector with Balanced Metering Servovalve, for an Internal Combustion Engine - The injector comprises a balanced metering servovalve to control a rod for the opening/closing of a nozzle. La servovalve has a valve body with a control chamber radially delimited by a tubular portion and fitted with an outlet passage that is opened/closed by an axially movable shutter. The servovalve is also integral with an axial stem, provided with a lateral surface, through which the outlet channel exits. The shutter is coupled to the stem in an axially sliding manner and, when it closes the outlet passage, it is subjected to substantially null axial fuel pressure. The outlet passage has a calibrated segment distanced from the shutter and close to a bottom wall of the control chamber. The calibrated segment is carried by an element fixed to the valve body in correspondence to an axial segment of the outlet passage. | 10-23-2008 |
20090032620 | METERING SERVOVALVE AND FUEL INJECTOR FOR AN INTERNAL COMBUSTION ENGINE - A metering servovalve for a fuel injector of an internal combustion engine has an electro-actuator and a fixed valve body, which defines a control chamber communicating with an inlet and with an outlet channel. The outlet channel has at least one calibrated restriction and exits through the lateral surface of an axial stem, on which a sleeve slides, in a substantially fluid-tight manner, to open/close the outlet channel and so vary the pressure in the control chamber. The outlet channel is closed by an end portion of the sleeve that is elastically deformable in a radially outward direction, under the thrust of the fuel pressure, to increase the diameter at which the seal against the valve body is formed, with respect to a non-deformed state, and to generate a radial unbalancing force on the sleeve upon opening when the outlet channel is closed. | 02-05-2009 |
20090032621 | METERING SERVOVALVE AND FUEL INJECTOR FOR AN INTERNAL COMBUSTION ENGINE - A fuel injector and servovalve for an internal combustion engine. In one embodiment, the fuel injector comprises a casing; a balanced metering servovalve in the casing that controls movement of an injection control rod along an axial cavity; said servovalve having; a valve body comprising a control chamber; an axial stem comprising a discharge channel having at least one radial segment that runs to a lateral surface of said axial stem; a calibrated inlet passage in communication with said control chamber; and an outlet passage in communication with said control chamber and the discharge channel; a sleeve having a shutter, said axial stem extending into said sleeve in a fluid tight manner and so that said sleeve that can axially slide along said axial stem between a closed position and an open position of said at least one radial segment, thereby controlling said movement of said injection control rod along said axial cavity; an electro-actuator having an armature that controls said axial sliding of said sleeve along said axial stem; an elastic member that exerts a force upon said armature that maintains said sleeve in said closed position, said electro-actuator being able to control said armature to overcome said force of said elastic member; and said armature being separate from said sleeve. | 02-05-2009 |
20090064971 | FUEL INJECTION SYSTEM COMPRISING A VARIABLE FLOW RATE HIGH-PRESSURE PUMP - An injection system includes a high-pressure pump with at least one pumping element operated in a reciprocating manner by corresponding intake and discharge strokes. Each pumping element is equipped with a corresponding intake valve in communication with an intake line, fed by a low-pressure pump. An on-off solenoid valve is positioned on the intake line of the pump and is controlled by a control unit with a frequency equal to a whole multiple or submultiple of that of the pumping action, multiplied by a factor different from 1 and/or between 0.90 and 1.10, inclusive. | 03-12-2009 |
20090320800 | FUEL INJECTOR WITH BALANCED METERING SERVOVALVE FOR AN INTERNAL-COMBUSTION ENGINE - The injector comprises a balanced metering servovalve for controlling a rod for opening/closing a nebulizer. The servovalve has a valve body having a control chamber provided with an outlet passage that is opened/closed by an axially mobile open/close element. The open/close element is made of a single piece with a bushing separate from an armature plate of an electromagnet. The bushing is coupled to a stem in an axially slidable way for closing an exhaust duct in communication with the outlet passage The open/close element is kept in a closed position by a spring that acts upon the bushing through an intermediate body connected thereto. The armature plate can be displaced with respect to the bushing between a flange of the intermediate body and a shoulder of the bushing, for eliminating the rebounds of the open/close element upon closing of the servovalve. | 12-31-2009 |
20090320801 | FUEL INJECTOR WITH HIGH STABILITY OF OPERATION FOR AN INTERNAL-COMBUSTION ENGINE - The injector comprises a dosing servo valve for controlling a rod for opening/closing a nebulizer. The servo valve has a valve body having a control chamber provided with an outlet passage that is opened/closed by an open/close element that is axially movable. The open/close element is separate from an anchor of an electromagnet, and is slidable on an axial guide element for closing the outlet passage. The open/close element is held in the closing position by a spring acting through an intermediate body. The anchor can be displaced with respect to the axial guide element between a flange of the intermediate body and a projection element of the guide member, for eliminating the rebounds of the open/close element upon closing of the solenoid valve. | 12-31-2009 |
20090320802 | FUEL INJECTOR PROVIDED WITH A METERING SERVOVALVE OF A BALANCED TYPE FOR AN INTERNAL-COMBUSTION ENGINE - A fuel injector has an injector body and a control rod, which is movable in the injector body along an axis for controlling opening/closing of a nozzle that injects fuel in an engine cylinder; the injector body houses a metering servovalve, provided with a control chamber and with an open/close element of a balanced type, axial sliding of which causes a variation in pressure in the control chamber; the metering servovalve comprises a valve body made of two pieces coaxially coupled to one another via a deformable ring, which defines also a gasket for guaranteeing fluid tightness between the two pieces and maintains in a fixed position a disk on which a calibrated restriction is made. | 12-31-2009 |
20090321542 | FUEL INJECTOR EQUIPPED WITH A METERING SERVOVALVE FOR AN INTERNAL COMBUSTION ENGINE - A fuel injector has an injector body and a control rod, which is movable in the injector body along an axis to control the opening/closing of a nozzle that injects fuel into a cylinder of the engine; the injector body houses a metering servovalve having a control chamber, which is axially delimited by the control rod and communicates with an inlet and with a discharge channel; the metering servovalve is provided with a shutter, which slides axially on an axial guide, from which the discharge channel exits, to open and close the discharge channel and, in consequence, vary the pressure in the control chamber; the discharge channel has at least two restrictions having calibrated passage sections and arranged in series with each other to divide the pressure drop along the discharge channel. | 12-31-2009 |
20100162992 | FUEL INJECTION SYSTEM WITH HIGH REPEATABILITY AND STABILITY OF OPERATION FOR AN INTERNAL-COMBUSTION ENGINE - The system comprises an injector controlled by commands of a control unit. The injector comprises a dosing servo valve having a control chamber provided with an outlet passage that is opened/closed by an open/close element that is axially movable. The open/close element is carried by an axial guide element that is separate from an anchor of an electromagnet. The open/close element is held in the closing position by a spring acting through an intermediate body. Preferably, the strokes of the open/close element and of the anchor are chosen so as to eliminate, upon closing of the solenoid valve, the rebounds of the open/close element subsequent to the first rebound. The control unit controls an injection comprising a pre-injection and a main injection, via two distinct electrical commands, which are spaced apart by a dwell time such as to occur in an area of reduced variation of the amount of injected fuel; therefore, the stability of operation of the system increases as said dwell time varies. | 07-01-2010 |