Nippondenso Co., Ltd.

Denso Corporation

Sadao Sumiya

Shinzo Ito

Hiroatsu Yamada

Fumio Kojima

Takashi Hieda

Tomihiko Nagata

Takumi Noma

Tatsuo Okada

Masakimi Nakano

Tateshi Katho

In a fuel injection valve, an adjustment pipe made of stainless steel and for adjusting a compression amount of a spring biasing a valve member is press-fitted into a cylindrical housing made of stainless steel, and a fuel injection amount is adjusted by adjusting a spring force of the spring in accordance with a press-fitted amount of the adjustment pipe. The adjustment pipe is immersed in an oxalic acid solution so that an oxalate film is formed thereon before being press-fitted into the cylindrical housing. Therefore, the oxalate film prevents a direct press-contact between an outer peripheral surface of the adjustment pipe and an inner peripheral surface of the cylindrical housing.

Adjustment pipe for fuel injection valve, and press-fitting structure and press-fitting method for the same

A method for adjusting the fuel injection quantity of an electromagnetic fuel injector having a needle valve, an electromagnetic actuator composed of a movable core which moves with the needle valve and a fixed iron core for attracting the movable core to move the needle valve to its open position, an adjust pipe inserted within a through hole of the fixed iron core, and a spring interposed between the adjust pipe and the movable core for continuously biasing the needle valve to its closed position, has the steps of inserting the adjust pipe into the through hole of the fixed iron core by a predetermined length and temporarily fixing the adjust pipe to the fixed iron core so as not to be moved by a force received from the spring when the needle valve is operated and so as to start moving when a force larger than the above described force of the spring is applied, running in the injector for a predetermined period of time, finely adjusting the position of the adjust pipe while checking the actual fuel injection quantity, and unmovably fixing the adjust pipe to the fixed iron core at such a position that the injector injects a desired injection quantity of fuel.

Method for adjusting fuel injection quantity of electromagnetic fuel

An assembling method of a fuel injection valve for fuel injection into an internal combustion engine, the fuel injection valve including a cylindrical valve body having a fuel passage therein and a through-hole made in a direction of the axis thereof and a cylindrical nozzle coupled to the valve body and having a plurality of injection holes for dividing the fuel exited from the through-hole into a plurality of parts and for injecting the divided fuel parts into the engine. The assembling method comprises the steps of coupling the nozzle to the valve body, rotating the valve body relative to the nozzle, and stopping the rotation of the valve body when the through-hole takes a desirable position relative to the injection holes and fixedly securing the nozzle to the valve body. Preferably, an end portion of the valve body is tapered conically and the nozzle has at least one edge portion at its inside so that the edge portion comes into contact with the tapered portion when the nozzle is coupled to the valve body, the edge portion being made of a material whcih is deformed non-elastically in response to application of a force. The edge portion is crushed flat when the nozzle is coupled to the valve body.

Fuel injection valve assembly and an assembling method therefor

Growing community of inventors

Takahama, Japan

Sadao Sumiya