Nippondenso Co., Ltd.

Shigeki Tojo

Masaaki Kato

Kazuyoshi Arai

Masahiro Okajima

Hiroyuki Kano

Yoshihiro Narahara

Hirotaka Nakatsuka

Tertada Kojima

A fuel injection valve of a diesel engine, comprising a valve body including a concave conical surface in the tip portion of the valve body, and fuel injection holes extending from the concave surface to the outside of the valve body, and a needle valve movable in the valve body and including a cylindrical shaft portion, a first conical surface adjacent to the shaft portion and having a conical angle smaller than that of the concave surface, the lower edge of the first conical surface defining a contact line separably contacting with the concave surface, a second conical surface adjacent to the first surface and having a conical angle substantially equal to that of the concave surface, a third conical surface adjacent to the second surface and having a conical angle greater than that of the concave surface. In case of a smaller lift amount of the needle valve, the fuel flow speed flowing into the fuel injection hole is fast and the atomized fuel injection divergence angle from the injection hole is great, thereby producing active producing mixing of the fuel with the air and enhancing the ignition feature, while in case of a greater lift amount, the fuel flow speed is slow and the atomized fuel injection divergence angle from the injection hole is small, thereby increasing the fuel flow reach and producing an active mixing of the fuel with the air by virtue of the kinetic energy of the atomized fuel flow.

Fuel injection valve having different fuel injection angles at different

A fuel injection nozzle of the present invention has an accumulating chamber in a body in which high pressure fuel fed from the fuel injection pump is stored using a non-return valve. A needle valve is arranged in the body to inject the fuel in the accumulating chamber. A nozzle needle of the needle valve and a valve member are arranged coaxially and in series with each other. Those end portions of the nozzle needle and valve member which are adjacent to each other are slidably and liquid-sealingly fitted together to define a damping chamber between the valve member and the nozzle needle. Further, a damping plunger is coaxially fitted into the valve member. A passage which connects the damping chamber with the side of the fuel injection pump is coaxially formed in the damping plunger and has a reduced area.

Fuel injection nozzle

A fuel injection nozzle of this invention includes a nozzle housing which defines therein a fuel sump chamber, stepped cylinder bore and fuel passage connected at one end to the sump chamber and at the other end to a smaller diameter bore section of a stepped bore. A stepped plunger is fitted into the stepped cylinder bore to define a pump chamber communicating with the fuel passage and a main fuel chamber into which the main fuel is supplied from a fuel injection pump. An auxiliary fuel is supplied from a feed pump through the fuel passage into the sump chamber and pump chamber. A nozzle needle is located within the nozzle housing and is responsive to a fuel pressure within the sump chamber to cause it to be lifted to permit an injection hole to be opened. The nozzle needle is urged under a predetermined force of a pressure spring in a direction in which the injection hole is blocked. The urging force of the pressure spring is set to be greater than the pressure of the auxiliary fuel supplied from the feed pump and smaller than the pressure of the main fuel supplied from the fuel injection pump. The main fuel chamber, when the plunger is moved a predetermined distance responsive to the fuel pressure within the main fuel chamber, is permitted to be connected to the fuel passage.

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Mie, Japan

Shigeki Tojo