Nissan Motor Company Limited

Atsuhiro Sakamoto

Toshikazu Oshidari

Shigeru Kamegaya

Iwane Inokuchi

This device diagnoses whether or not a fuel pump which supplies fuel to an engine has failed. The pump includes a plurality of pressure chambers which in turn discharge fuel according to the rotation of an input shaft which turns together with the engine. The supply capacity of the fuel pump when one of the pressure chambers has failed so as not to be able to discharge fuel is set to a value lower than the maximum value of the fuel supply amount which is required by the engine. A mechanism is provided which decides whether or not the fuel supply requirement of the engine is being satisfied, and failure of the fuel pump is diagnosed based upon the result of this decision. Further, accurate diagnosis can be performed by detecting the power output of the engine for each cylinder individually, and by deciding upon fuel supply insufficiency for each cylinder individually according to variation of the output power for each cylinder individually.

Failure diagnosis device for a fuel pump

Fuel is pressurized by the expansion and contraction of a pump chamber defined inside a casing according to the rotation of a power input shaft which penetrates from the outside of the casing into its inside. A first seal member is provided between the casing and the power input shaft and prevents escape of fuel which is inside the casing, and a second seal member is provided in series therewith. Further, leakage of fuel to the outside of the casing from the second seal member is prevented by the provision of a drain conduit which drains fuel which has leaked into a space defined between the first seal member and the second seal member.

Fuel pump

A cam plate pump comprises a pressurizing chamber formed by a bellows which elongates and contracts along a center axis parallel to the input shaft of the pump. The cam plate rotates together with the input shaft, and compresses the bellows via a piston. A mechanism for guiding the piston along the center axis, and a mechanism for blocking the rotational torque acting on the bellows via the piston are provided. These mechanisms prevent a bending load or twisting load from acting on the bellows.

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Zushi, Japan

Atsuhiro Sakamoto