Abstract: A fuel injection device has a nozzle body formed with an injection hole for injecting fuel and a nozzle needle reciprocating in the nozzle body to open and to close the injection hole. The nozzle needle has a sliding portion capable of moving in the nozzle body in a sliding manner, an insertion portion, of which diameter is smaller than that of the sliding portion, and a pressure receiving portion connecting the sliding portion with the insertion portion. The nozzle body has a guide portion for slidably holding the sliding portion and a fuel sump chamber formed on the injection hole side of the guide portion. The insertion portion is inserted through the fuel sump chamber. A clearance decreasing toward the fuel sump chamber is provided between the guide portion and the sliding portion.

Abstract: A fuel injection device has a nozzle body formed with an injection hole for injecting fuel and a nozzle needle reciprocating in the nozzle body to open and to close the injection hole. The nozzle needle has a sliding portion capable of moving in the nozzle body in a sliding manner, an insertion portion, of which diameter is smaller than that of the sliding portion, and a pressure receiving portion connecting the sliding portion with the insertion portion. The nozzle body has a guide portion for slidably holding the sliding portion and a fuel sump chamber formed on the injection hole side of the guide portion. The insertion portion is inserted through the fuel sump chamber. A clearance decreasing toward the fuel sump chamber is provided between the guide portion and the sliding portion.

Abstract: A fuel injection device has a nozzle body formed with an injection hole for injecting fuel and a nozzle needle reciprocating in the nozzle body to open and to close the injection hole. The nozzle needle has a sliding portion capable of moving in the nozzle body in a sliding manner, an insertion portion, of which diameter is smaller than that of the sliding portion, and a pressure receiving portion connecting the sliding portion with the insertion portion. The nozzle body has a guide portion for slidably holding the sliding portion and a fuel sump chamber formed on the injection hole side of the guide portion. The insertion portion is inserted through the fuel sump chamber. A clearance decreasing toward the fuel sump chamber is provided between the guide portion and the sliding portion.

Abstract: In a fluid injection nozzle, a leading end portion of a needle is provided with a first conical surface, a second conical surface and a notch. A seat line between the first and second conical surfaces comes in contact with a seat surface. A gap between the first conical surface and the seat surface gradually narrowed as going downstream, and a gap between the second conical surface and the seat surface gradually widened as going downstream. The notch extends from an upstream end of the first conical surface to a side opposite from the second conical surface to face the seat surface.

Abstract: A fuel injector for an internal combustion engine includes a nozzle body, a needle, a control piston and a force disperser. The nozzle body has a valve seat for starting and stopping fuel injection. The needle is slidably disposed in the nozzle body and has a valve head for seating on the valve seat. The control piston is for transmitting a drive force to the needle. The force disperser disperses the drive force when the needle displaces a predetermined distance relative to the nozzle body. The force disperser provides for an elastic deformation of at least one of the nozzle body and the needle to prevent concentration of the drive force on the valve seat and the valve head.

Abstract: A fuel injection device has a nozzle body formed with an injection hole for injecting fuel and a nozzle needle reciprocating in the nozzle body to open and to close the injection hole. The nozzle needle has a sliding portion capable of moving in the nozzle body in a sliding manner, an insertion portion, of which diameter is smaller than that of the sliding portion, and a pressure receiving portion connecting the sliding portion with the insertion portion. The nozzle body has a guide portion for slidably holding the sliding portion and a fuel sump chamber formed on the injection hole side of the guide portion. The insertion portion is inserted through the fuel sump chamber. A clearance decreasing toward the fuel sump chamber is provided between the guide portion and the sliding portion.