FLOW CONTROL SYSTEM

摘要

A flow control system for a fuel injector for an internal combustion engine is provided and includes an inlet port, an outlet, a return port, a 2-way control valve including a control valve member, a shuttle valve and a main valve. The control valve includes a first seat, a first resilient arrangement configured to force the control valve member towards the seat so as to close the control valve, and a first abutment that limits the lift of the control valve member away from the first seat. The first seat of the control valve is slidably arranged in the shuttle control chamber. An end stop for the first seat is provided such that the pressure in a shuttle control chamber tends to move the first seat towards the end stop. The first seat, upon its mechanical contact with a valve member is able to transmit at least a part of the force of the resilient means onto a shuttle valve body in the opening direction of the shuttle valve.

主权项

1. A flow control system, in particular for a fuel injector for an internal combustion engine, the flow control system comprising:
an inlet port for receiving a fluid having a relatively high pressure, an outlet for letting out the pressurized fluid, a return port for returning part of the fluid to a volume having a relatively low pressure, a 2-way control valve comprising a control valve member, a first seat, a first resilient means configured to force the control valve member towards the seat so as to close the control valve, and a first abutment that limits the lift of the control valve member away from the first seat, a main valve comprising a main valve member, a second seat, a main control chamber, and an outlet chamber in fluid connection with the inlet port, the main valve member being configured to be forced by pressure in the main control chamber towards the second seat so as to close an opening to the outlet, a shuttle valve comprising a shuttle valve body, a shuttle control chamber and a third seat, the shuttle valve body being configured to engage with the third seat so as to close an opening between the inlet port and the main control chamber; a connection channel configured to connect the shuttle control chamber with the main control chamber, wherein the control valve is configured to close and open a connection between the shuttle control chamber and the return port and is biased towards its closed position by the first resilient means, the shuttle valve is biased closed by a second resilient means, the main valve is configured to open and close a connection between the inlet port and the outlet and is biased closed by the second resilient means, further wherein the shuttle valve is configured such that the pressure in the shuttle control chamber tends to open the shuttle valve whereas the pressure in the main control chamber tends to close the shuttle valve, wherein the main valve is configured such that the pressure in the main control chamber tends to close the main valve whereas a pressure in the outlet chamber tends to open the main valve, wherein the first seat of the control valve is slidably arranged in the shuttle control chamber and wherein an end stop for the first seat is provided such that the pressure in the shuttle control chamber tends to move the first seat towards the end stop, further wherein the first seat, upon its mechanical contact with the valve member, is able to transmit at least a part of the force of the resilient means onto the shuttle valve body in the opening direction of the shuttle valve.