Fuel injection device
AssigneeDenso Corporation
InventorsNao Ogasawara, Daiji Ueda
Life of this patent
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Abstract
A fuel injection device has a valve body, a drive portion, a nozzle needle, and a control valve body. The valve body defines a control chamber, a valve chamber and a low pressure communication passage. The nozzle needle is displaced due to a fuel pressure variation in the control chamber to open/close an injection port. When the control valve body sits on an upper seat surface, a low pressure communication passage is closed so that the valve chamber is fluidly disconnected from the low pressure chamber. The control valve body defines a gap restriction on the upper seat surface. A flow passage area of a sub orifice provided to the low pressure communication passage is smaller than a flow passage area of the gap restriction.
Claims8
A fuel injection device for injecting a fuel from an injection port comprising:
- a body defining the injection port, a control chamber filled with the fuel, a valve chamber communicating with the control chamber, and an outflow passage for discharging the fuel in the valve chamber into a pressure chamber;
- a control plate accommodated in the control chamber;
- a valve member which is displaced by a variation in a fuel pressure in the control chamber to open/close the injection port;
- a control valve body accommodated in the valve chamber in such a manner as to be capable of disconnecting the valve chamber and the pressure chamber by sitting on an outflow seat surface formed on a partition wall which defines the valve chamber;
- and
- a driving portion driving the control valve body in such a manner that the control valve body sits on the outflow seat surface or moves away from the outflow seat surface, wherein
- the control valve body defines a gap restriction on the outflow seat surface when the valve chamber communicates with the pressure chamber through the outflow passage;
- the outflow passage has an outflow orifice which limits a flow rate of the fuel flowing out from the valve chamber into the pressure chamber,
- the outflow orifice has a flow passage area which is smaller than a flow passage area of the gap restriction,
- the body defines a communication passage which fluidly connects the control chamber and the valve chamber,
- the communication passage has a communication orifice of which a flow passage area is smaller than the flow passage area of the outflow orifice, and
- the communication orifice is defined within the control plate.
Dependencies are inferred from the claim text.