A fuel injector is provided that creates variable spray characteristics to effectively reduce emissions, such as NOx emissions and particulate matter. The injector includes a nozzle valve element of the outwardly opening type including a fuel delivery passage and spray holes. The nozzle valve element is operable to move to a low lift position to cause fuel flowing from the spray holes to impinge on the injector body and to deflect toward the combustion chamber, and to move to a high lift position to cause fuel flowing from the spray holes to avoid impingement on injector body and flow in an obstructed manner directly into the combustion chamber. An annular chamber may be formed in the nozzle valve element adjacent the spray holes to receive fuel.

The present disclosure relates to internal combustion engines. The teachings thereof may be embodied in injection valves with servo-valve control for injecting fuel into the combustion chamber. For example, an injection valve may include a valve pin connected to a valve body and an actuator preloaded by an actuator spring. The valve pin is fitted with a very small clearance to form a sealing gap between the valve pin and the valve body which includes bores. The lower end of the valve pin forms a coupling volume between the valve pin and the valve body, connected via the sealing gap and the bores to the valve chamber. The sealing gap provides a fluidic connection between the coupling volume and the valve chamber, but, during the short time of valve actuation, practically no exchange of fluid can take place between coupling volume and valve chamber so that the coupling volume does not substantially change in said short time.

A filter for filtering hydraulic fluid in a hydraulically actuated fuel injector. The filter includes a first disc structure and a second disc structure disposed axially spaced apart from the first disc structure. The second disc structure is also disposed parallel to the first disc structure. The filter further includes an intermediate structure extending from the first disc structure to the second disc structure. The intermediate structure includes a first surface and a second surface disposed opposite and parallel to the first surface. The intermediate structure defines a plurality of passages extending from the first surface to the second surface. Each of the plurality of passages is perpendicular to a longitudinal axis of the filter.

A method for monitoring an injector for common-rail injection systems includes detecting an electrical signal indicative of a deformation of a diaphragm of a head plate having a reaction surface facing a control chamber of the injector and processing the deformation signal to determine characteristic data of the operation of the injector.

A high pressure hydraulic system comprising: a hydraulic chamber containing pressurized fluid, a wall which encloses at least one part of the hydraulic chamber and has an integral diaphragm, a piezoelectric sensor isolated from the pressurized fluid contained in the hydraulic chamber by the diaphragm, and an elastic element arranged to apply an elastic force to the piezoelectric sensor, between the piezoelectric sensor and the diaphragm, so that a deformation of the diaphragm produced by a change in the pressure of the fluid contained in the hydraulic chamber causes a change in the elastic force that the elastic element applies to the piezoelectric sensor.

A filter for filtering hydraulic fluid in a hydraulically actuated fuel injector. The filter includes a first disc structure and a second disc structure disposed axially spaced apart from the first disc structure. The second disc structure is also disposed parallel to the first disc structure. The filter further includes an intermediate structure extending from the first disc structure to the second disc structure. The intermediate structure includes a first surface and a second surface disposed opposite and parallel to the first surface. The intermediate structure defines a plurality of passages extending from the first surface to the second surface. Each of the plurality of passages is perpendicular to a longitudinal axis of the filter.

A valve assembly may include: a valve body with a longitudinal axis and a cavity; a valve needle; and a driving device for displacing the valve needle. In some embodiments, the valve needle comprises a disc element. The disc element and the driving device comprise mutually facing and radially extending coupling surfaces, the coupling surfaces having an overlapping area of at least 35% of the cross-sectional area of the cavity. The driving device takes the disc element with it for displacing the valve needle in the opening direction solely by means of hydraulic interaction between the coupling surfaces when the driving device is displaced in the opening direction. The coupling surface of the driving device engages in a form-fit connection with the coupling surface of the disc element for pushing the valve needle towards the closing position.

A piezo injector includes an actuator space in which a piezo actuator is arranged, a control piston bore in which a control piston with an end face is arranged, a leakage pin arranged between the piezo actuator and the end face to couple the piezo actuator with the control piston, and a union for fluidic communication with the control piston bore which union has a hydraulic throttle.

The present disclosure relates to an injection valve comprising an injector body, a needle body, a control space, a control valve, and a piezoelectric actuator. The injector body has a recess and a fluid inflow and a fluid outflow. The needle body is arranged axially movably in the recess of the injector body and suppresses a fluid flow through an injection opening of the injector body in a closed position of the needle body and otherwise releases it. The control space is disposed in the recess between the fluid inflow and the fluid outflow. The control valve may be arranged in the control space to suppress a fluid flow between the control space and the fluid outflow in a closed position of the valve body and to otherwise release it. The piezoelectric actuator may be coupled mechanically to the control valve via a first transmitter for opening the control valve.

The present disclosure relates to internal combustion engines. The teachings thereof may be embodied in injection valves with servo-valve control for injecting fuel into the combustion chamber. For example, an injection valve may include a valve pin connected to a valve body and an actuator preloaded by an actuator spring. The valve pin is fitted with a very small clearance to form a sealing gap between the valve pin and the valve body which includes bores. The lower end of the valve pin forms a coupling volume between the valve pin and the valve body, connected via the sealing gap and the bores to the valve chamber. The sealing gap provides a fluidic connection between the coupling volume and the valve chamber, but, during the short time of valve actuation, practically no exchange of fluid can take place between coupling volume and valve chamber so that the coupling volume does not substantially change in said short time.