Methods and systems are provided for a direct injection fuel pump. The methods and system control pressure within a compression chamber so as to improve fuel pump lubrication.

The invention relates to a fuel injection device (100) for a compression-ignition engine, comprising a first storage unit (20) which can be supplied with fuel by at least one high-pressure pump (16), the first storage unit (20) being arranged preferably inside the high-pressure pump (16), a first connecting line (26) from the first storage unit (20) to a second storage unit (30), and a second connecting line (40) from the second storage unit (30) to a fuel injector (50).

A method for operating an internal combustion engine having an injection system which has a high-pressure accumulator, wherein a high pressure in the high-pressure accumulator is regulated via a suction throttle on the low-pressure side as a first pressure control member in a first high-pressure control loop, wherein in a normal operation a high-pressure disturbance variable is produced via a pressure control valve on the high-pressure side as a second pressure control member, via which fuel is redirected from the high-pressure accumulator to a fuel reservoir. For this purpose, the high pressure in a safety operation is regulated by the pressure control valve via a second high pressure control loop, or, in the safety operation, a maximum fuel volume flow is continuously redirected from the high pressure accumulator to the fuel reservoir via the pressure control valve.

A dual-fuel injector for a fuel injection device, including: a liquid fuel injector unit with a nozzle needle assigned to a liquid fuel nozzle arrangement of the dual-fuel injector and which is stroke controllable via a first control chamber; and a gas injector unit with a gas nozzle needle assigned to a gas nozzle arrangement of the dual-fuel injector and which is stroke controllable via a second control chamber. Each of the control chambers can be impinged with a control fluid to control the stroke of the respective nozzle needle. The control fluid from both the control chambers can be discharged. The dual-fuel injector has a control fluid reservoir in which discharged control fluid from the first control chamber can be introduced; the dual-fuel injector is configured to impinge the second control chamber with control fluid from the control fluid reservoir for the stroke control of the gas nozzle needle.

An object of the present invention is to provide a fuel injection system capable of suppressing an occurrence of distortion in an injector during assembly of components. A fuel injection system (3) includes: a bracket (5) which is fixed to a cylinder head (21) of an engine (2); a fuel accumulator (6) which is supported by and fixed to the bracket (5) and which accumulates pressure of fuel supplied from a fuel pump; and an injector (7) which is directly connected to the fuel accumulator (6) and mounted to the cylinder head (21) and which injects the fuel, supplied from the fuel accumulator (6), into a combustion chamber. At least one of the fuel accumulator (6) and the bracket (5) has guide members (64, 513) which guide the injector (7) to a mount position on the cylinder head (21).

A method for determining a leakage of fuel in a high-pressure region of a fuel supply system for an internal combustion engine of a vehicle. A curve of a pressure in a high-pressure accumulator of the fuel supply system is provided. A value for a pressure drop is determined in each of one or more segments of the curve, wherein in one segment or in each of the plurality of segments the vehicle is in overrun, no fuel is injected into the internal combustion engine, and no fuel is pumped into the high-pressure accumulator. Information about the leakage is determined on the basis of the one or more values.

Fuel injector for supplying fuel to a combustion chamber of a cylinder, having a first nozzle needle guided in a first nozzle guide, which interacts with first fuel injection orifices such that the first nozzle needle either opens or blocks a fuel flow of a first fuel through the first fuel injection orifices, a second nozzle needle guided in a second needle guide, which interacts with second fuel injection orifices such that the second nozzle needle, either opens or blocks a fuel flow of a second fuel through the second fuel injection orifices, a first fuel storage space for the first fuel, and a second fuel storage space for the second fuel me. The first and second fuel storage spaces are arranged next to one another in the transverse or radial direction of the fuel injector and overlap in the longitudinal or axial direction of the fuel injector.