The disclosure relates to a control method for controlling at least one injector valve in a fuel injection system of an internal combustion engine. An opening time of the injector valve is selected such that, in a fault situation in the fuel injection system, an opening time of the injector valve is situated in a pressure valley of a pressure oscillation prevailing in a high-pressure region of the fuel injection system.

A fuel pump includes a mechanical regulating valve arranged in a pump body which modulates the pressure in a high pressure space so that the pressure matches the engine demand. Modulation by the regulating valve requires adjustment of the inlet fuel quantity, adjustment of the volume of the high pressure space, and control of a return fluid communication enabling fuel to exit the high pressure reservoir.

An outlet valve includes an outlet valve housing with an outlet valve bore including an outlet valve seating surface. The outlet valve also includes an outlet valve member which moves within the outlet valve bore second portion between a closed position and an open position. A surface of the outlet valve bore guides the outlet valve member during movement between the closed position and the open position. The surface of the outlet valve bore and the outlet valve seating surface are provided on a continuous piece of material of the outlet valve housing. An outlet valve spring biases the outlet valve member toward the closed position and a retainer is fixed to the outlet valve housing which grounds the outlet valve spring to the outlet valve housing.

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 estimation unit estimates a fuel pressure on a discharge side of a high-pressure pump based on an amount of fuel injection with a fuel injection valve from a time point at which a detected fuel pressure changes from a higher status than a first pressure to a lower status, assuming that the fuel has not been discharged with the high-pressure pump. The determination unit determines that a relief valve is in an open status based on a dropping mode of the estimated fuel pressure and a dropping mode of the detected fuel pressure.

A valve arrangement for a fuel injection system includes a first valve unit (42) having a first flow cross section (Q.sub.1) and a second valve unit (44) having a second flow cross-section Q.sub.2). The second valve unit includes at least two single valves (48), each of which has a single valve flow cross-section Q.sub.E). The second flow cross-section (Q.sub.2) is formed by a sum of the single valve flow cross-sections (Q.sub.E). A fuel injection system (10) incorporates such a valve arrangement (22).

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 fuel system is disclosed for use with an engine, including a fuel injector assembly fluidly coupled with a low-pressure fuel conduit, an accumulator, and a cap within an opening in the accumulator. The fuel injector assembly may be structured to draw in low-pressure fuel, pressurize the fuel, and store the pressurized fuel in the accumulator for injection to a combustion chamber. The cap has a pressure sensor and a pressure relief valve therein, and drains fuel leaked past fluid seals between the cap and each of the pressure sensor, the pressure relief valve, and the accumulator by way of a common drain line.

A pressure release valve, having three or more cavities is described. The pressure release valve comprises a valve body with at least three valve cavities for fluid. The first valve cavity contains high-pressure fluid and the second cavity contains low-pressure fluid. The first, second, and third cavities are separate and apart from one another. The pressure release valve further includes a movable valve body shaft with a valve hammer and an elastic spring body. The pressure release valve further includes a channel and a valve port, wherein when pressure is applied to the movable valve body shaft, the movable valve body shaft is actuated to press against the valve hammer forcing the valve hammer to move opening the port allowing fluid to flow from the first cavity, to the second cavity and the third cavity.

An object of the present invention is to provide a high-pressure fuel supply pump that can restrict lowering of pressure and generation of cavitation in the vicinity of a seat by providing a throttle in a relief spring holder. Accordingly, in order to achieve the above object, the present invention relates to a fuel supply pump that includes a pressurizing chamber configured to pressurize fuel, and a relief valve mechanism configured to return fuel in a discharge path on a downstream side of the discharge valve to the pressurizing chamber. The relief valve mechanism includes a relief seat configured to close a relief channel when a relief valve is seated, a relief spring configured to energize the relief valve to the relief seat, and a relief spring holder configured to hold the relief spring. In the relief spring holder, a throttle section is formed in a fuel path for returning from a relief chamber in which the relief spring is disposed to the pressurizing chamber and the channel. The above object can be achieved by the above configuration.