A method for operating an internal combustion engine with a motor having a number of cylinders and an injection system having a common rail with a number of injectors assigned to the cylinders and similar high pressure components, which is designed to hold fuel from the common rail for the injector, wherein the method has the steps: injecting fuel from the common rail into a cylinder by way of an injector, determining a fuel pressure for a high-pressure component, in particular the common rail, the injector and/or the individual reservoir, having at least one high-pressure sensor measuring the fuel pressure. Provision is made for a defect in the high-pressure sensor to be detected in that a check is made as to whether magnitude of the high-pressure control deviation (ep) during a predetermined time interval (t.sub.Limit1.sup.SD, t.sub.Limit2.sup.SD, t.sub.Limit3.sup.SD) exceeds a predetermined limiting value (e.sub.Limit1.sup.SD, e.sub.Limit2.sup.SD, e.sub.Limit3.sup.SD).

Various methods and systems are provided for a pressure relief valve of a fuel system. In one example, a valve includes a first chamber in fluid communication with a first fuel line, a second chamber in fluid communication with a second fuel line and in fluid communication with a fuel storage tank, a piston separating the first chamber from the second chamber, and a needle coupled to the piston and controlling a flow passage between the second fuel line and the second chamber, where the piston and needle are sized such that a force applied on the piston by the first chamber parallel to an axis of movement of the piston maintains the needle in a closed position when the first fuel line flows fuel at a first pressure and the second fuel line flows fuel at a second pressure, the second pressure greater than the first pressure.

An object is to suppress cavitation generated at a distal end portion of a seat face when a valve body and a seat portion collide with each other. In a relief valve of a fuel pump, an intersection between the seat face and a flow channel hole is formed at a position more distant than the seat portion formed of the valve body in a valve closing state and the seat face in order to suppress generation of cavitation bubbles when the valve body improves and releases high-pressure fuel.

Various teachings of the present disclosure may be embodied in a fuel rail assembly for a combustion engine comprising: an elongated tubular fuel rail; a fuel delivery pipe unit hydraulically coupled to the fuel rail; an injector cup for receiving a fuel injector, a pipe coupled to the cup and to the rail, and at least one fixation unit for fixing the pipe unit to the engine. The fixation unit comprises a connecting element fixed to a predetermined pipe unit portion by a first filler material joint. The connecting element, absent the first filler material joint, is axially and rotatably movable relative to the pipe and the injector cup. The fixation unit includes a bracket element with a through hole for a bolt to the engine. The bracket element is fixed to a predetermined connecting element portion by a second filler material joint. The bracket element, absent the second filler material joint, is laterally movable with respect to the connecting element for adjusting its radial distance from the pipe and the injector cup.

The invention relates to a pressure regulator for a high-pressure ramp of a system for injecting fuel into an internal combustion engine, comprising a solenoid valve element (10) which receives an electromagnet (40). The electromagnet controls a needle (20) that closes a valve seat (30) which is connected to a high-pressure inlet and opens into a discharge chamber (13), said discharge chamber communicating with a liquid recirculation system (5) by means of outlet openings (14). The rear face (12) of the solenoid valve element (10) receives a coil (40) which controls the opening process of an armature (41) that is rigidly connected to the needle (20) and is subject to a closing return spring (25). The discharge chamber (13) is located on the front face (11) of the solenoid valve element (10) on the axis (XX) of the needle (20), and the discharge chamber surrounds the needle. A cavity (15) passes through the discharge chamber, said cavity receiving an inlet valve element (50), and a bore (51) which opens into the valve seat (30) passes axially through the inlet valve element. The discharge chamber (13) through which the needle (20) passes axially and the outlet openings (14) which are connected to the liquid recirculation system open transversally into a wall (131) in the discharge chamber (13) below the upper part (132) of the chamber. The regulator is characterized that the regulator comprises an annular expansion (70) of the discharge chamber (13) below the outlet openings (14) along the extension of a conical surface (31), which forms the valve seat (30) and an annular dead volume (70), above the surface (54) of the valve element (50), which forms the base of the discharge chamber (13) and has the valve seat (30) in the center of the valve element.

A fuel return device couples to the high pressure side of a DI fuel system. The fuel return device provides for both continuous bleeding and occasional purging of fuel from the high pressure side to prevent issues related to vapor accumulation or heat-induced pressure increase. The fuel return device may be attached to a high pressure fuel rail in place of a sensor. The sensor may be attached the fuel return device. The fuel return device may include both an orifice that throttles the fuel flow through the fuel return device and a solenoid that allows the flow rate to be increased.

A high-pressure injection device for an internal combustion engine to which engine segment times are assigned, having a high-pressure pump, a rail connected to the high-pressure pump via a high-pressure fuel line, at least one injector, a digital pressure reduction valve connected to the rail, a fuel return line connected to the pressure reduction valve, and a control unit. The control unit is configured to switch the pressure reduction valve into the transmissive state only in predetermined engine segment times, and to maintain said transmissive state of the pressure reduction valve for a time period which is greater than the duration of one engine segment time.

Methods and systems are provided for adjusting operation of fuel injectors of an internal combustion engine to reduce injector ticking noise during direct injection fuel rail pressure release. The method includes first reducing a significant part of the direct injection fuel rail pressure via a mechanical high pressure pump relief valve and only if further pressure relief is required then intermittently activating the direct injector to inject in small amount of fuel. Due to the reduced frequency of activation and small pulse-widths, the impact force transmitted from injectors to cylinder head is small thereby reducing the objectionable ticking noise.

A pressure control valve for a fuel injection system, in particular a common-rail injection system, for controlling pressure in a high-pressure fuel reservoir, includes a magnetic actuator configured to actuate a spherical valve closing element. The magnetic actuator interacts with a reciprocatingly displaceable armature that is connected to an armature pin in order to transmit a force of the magnetic actuator to the spherical valve closing element. At least one of the spherical valve closing element and the armature pin is axially displaceably guided in a valve piece which forms a valve seat configured to interact with the spherical valve closing element.

A method for testing a high-pressure pump, particularly a high-pressure pump which is provided to inject fuel into a combustion engine, the method including filling the high-pressure pump with a fluid prior to switching it on.