A flow control system for a fuel injector of an internal combustion engine includes: an inlet channel, an outlet channel, a return channel for returning pressurized fuel to a low-pressure system having a lower pressure than the inlet channel, a fuel outlet chamber, a moveable nozzle control member in the fuel outlet chamber for selectively allowing the pressurized fuel to flow into the outlet channel, a biasing member biasing the nozzle control member towards a closed position, a moveable member defining, with the nozzle control member, a fuel control chamber configured to bias the nozzle control member towards its closed position, a moveable valve member for selectively opening and closing a flow passage and a fuel connection between the inlet channel and the fuel control chamber for pressurizing the fuel control chamber.

A flow control system for a fuel injector of an internal combustion engine includes: an inlet channel, an outlet channel, a return channel for returning pressurized fuel to a low-pressure system having a lower pressure than the inlet channel, a fuel outlet chamber, a moveable nozzle control member in the fuel outlet chamber for selectively allowing the pressurized fuel to flow into the outlet channel, a biasing member biasing the nozzle control member towards a closed position, a moveable member defining, with the nozzle control member, a fuel control chamber configured to bias the nozzle control member towards its closed position, a moveable valve member for selectively opening and closing a flow passage and a fuel connection between the inlet channel and the fuel control chamber for pressurizing the fuel control chamber.

A fuel injection system of an internal combustion engine includes: an injector having a hydraulic control chamber controlling the delivery of fuel through the injector, an actively controlled first valve system controlling the pressure relief from the control chamber, movable between: a first position in which the first valve system closes the injector by deterring the pressure from being relieved from the control chamber through the first relief circuit, and a second position in which the first valve system opens the injector by allowing the pressure to be relieved from the control chamber through the first relief circuit. A second relief circuit allows the pressure to be relieved from the control chamber through the second relief circuit. The second relief circuit includes a second valve system passively controlled by the fuel pressure and movable between two positions deterring or allowing the pressure to be relieved from the control chamber through the second relief circuit.

A fuel injector includes an injector housing, a check control valve assembly within the injector housing, a direct-operated check, a valve biaser supported on the injector housing, and a dry-running protection valve trapped between the valve biaser and the injector housing. The dry-running protection valve limits expelling drained actuation fluid from the fuel injector to enable filling a low-pressure volume therein in advance of filling a low pressure drain line common to a plurality of fuel injectors in an internal combustion engine system.

A method is provided for achieving final air gap and parallelism of a control valve of a fuel injector, the control valve having a body defining an transverse top face and including a thick disc magnetic armature having a planar transverse upper face. The method includes a) measuring the actual position from the armature upper face and the body top face and, determining the actual parallelism error between said faces; and b) ablating the armature to generate an ablated upper face parallel to the body top face, the distance from the ablated upper face to the body top face being a final air gap.

The fuel injection valve includes a valve body having an injection hole at an end of the valve body facing in a first direction, and a needle valve provided inside the valve body and movable in an axial direction which includes both the first direction and a second direction opposite to the first direction. The needle valve is driven in the axial direction by a change in internal pressure of a back pressure chamber in the valve body. The fuel injection valve includes a control valve that controls the internal pressure of the back pressure chamber, and an actuator that drives the control valve. The control valve is longer than the needle valve in the axial direction. An end of the control valve facing in the second direction and the actuator are arranged away in the second direction from a center of the valve body in the axial direction.

A fuel injection system of an internal combustion engine includes: an injector having a hydraulic control chamber controlling the delivery of fuel through the injector, an actively controlled first valve system controlling the pressure relief from the control chamber, movable between: a first position in which the first valve system closes the injector by deterring the pressure from being relieved from the control chamber through the first relief circuit, and a second position in which the first valve system opens the injector by allowing the pressure to be relieved from the control chamber through the first relief circuit. A second relief circuit allows the pressure to be relieved from the control chamber through the second relief circuit. The second relief circuit includes a second valve system passively controlled by the fuel pressure and movable between two positions deterring or allowing the pressure to be relieved from the control chamber through the second relief circuit.

A method is provided for achieving final air gap and parallelism of a control valve of a fuel injector, the control valve having a body defining an transverse top face and including a thick disc magnetic armature having a planar transverse upper face. The method includes a) measuring the actual position from the armature upper face and the body top face and, determining the actual parallelism error between said faces; and b) ablating the armature to generate an ablated upper face parallel to the body top face, the distance from the ablated upper face to the body top face being a final air gap.

A fuel injector is provided. The fuel injector is operable to inject fuel at extremely high pressures which creates very small droplet sizes, allowing for efficient self-ignition of the fuel and allows for clean, efficient combustion due to the small droplet sizes. The fuel injector uses pressure from within a combustion chamber to actuate the spraying of fuel from the injector, thereby solving many problems experienced by typical fuel injectors and eliminating many problem-components of prior art fuel injectors.

A fuel injector for an internal combustion engine, which is configured for feeding fuel to a cylinder, having a housing, via which the fuel injector can be mounted to the internal combustion engine, a valve body engaging with a valve stem interacting with a valve seat, which can be moved relative to the valve seat for opening a fuel flow, having a bellows sealing element, which with a first end engages with the valve stem and with a second end with the housing, a sleeve body, which at least partly decouples the bellows sealing element from a fuel flow through the fuel injector and from fuel pressure pulsations.