Between a movable core chamber and a fuel supply passage, a needle guide slidably supports a needle fixed to a movable core. The needle guide has a communication hole which fluidly connects the movable core chamber and the fuel supply passage. An opening sectional area of the communication hole is defined in such a manner that a fuel discharged amount decreases as an energization start time of a coil is delayed. In a suction stroke, it is restricted that the movable core and the needle bounce toward the fixed core after the needle biases a suction valve toward a stopper by means of a biasing force of a second spring. A relationship between the energization start time of the coil and the fuel discharged amount is properly maintained, so that the fuel discharged amount of the high-pressure pump can be controlled correctly.

High pressure pump

A high-pressure fuel pump, comprising a cylinder having a pressurizing chamber and a plunger inserted into the cylinder, wherein the plunger is reciprocated in axial direction by a lifter to pressurize the fuel inside the pressurizing chamber, a seal member surrounds the portion of the plunger projected from the cylinder, cuts out a cylinder side space surrounded by the seal member from a lifter side space on the outside of the seal member, and comprises an annular lip part in contact with the outer peripheral surface of the plunger, the annular lip part further comprises a pair of lips moving apart from each other in the axial direction of the plunger, and the axial distance between both lips is larger than the stroke of the plunger, whereby fuel does not invade into the lifter side space, and the lubricating oil lubricating the lifter does not invade into the cylinder side space.

High-pressure fuel pump

In a high pressure fuel supply pump for transmitting rotation of a cam to a reciprocating plunger via a tappet and a retainer, a diametric force acting on the plunger is reduced. The pump includes the retainer disposed on the plunger and a return spring exerting an urging force on the retainer in a direction of the tappet. A clearance between a plunger leading end and a tappet bottom surface opposed thereto is set to be greater than a clearance between a retainer bottom surface and the tappet bottom surface opposed thereto, and a clearance between a retainer inside diameter section and a plunger peripheral surface section opposed thereto is set to be greater than a clearance between a retainer outside diameter section and a tappet inner wall opposed thereto.

High-pressure fuel supply pump

A fluid pressure pulsation damper mechanism comprising: a metal damper (120) having two metal diaphragms joined together with a hermetic seal for forming a sealed spacing filled with a gas between the two metal diaphragms, an edge part at which are overlapped along outer peripheries thereof; a main body (126) having a damper housing in which the metal damper is accommodated; and a cover (128) attached to the main body (126) to cover the damper housing and isolate the damper housing from an outside air, the metal damper (120) being held between the cover and the main body; wherein the cover is further comprising: a metal plate for making the cover (128), a peripheral edge of the cover being joined to the main body (126) , a plurality of inner convex curved parts extending toward the main body (126).

Fluid pressure pulsation damper mechanism and high-pressure fuel pump equipped with fluid pressure pulsation damper mechanism

A mechanism for reducing pressure pulsation includes a pair of metal dampers formed by joining two disk-shaped metal diaphragms over an entire circumference and forming a hermetically sealed space inside a joined portion, with gas being sealed in the aforementioned hermetically sealed space of the damper, has a pair of pressing members which give pressing forces to both outer surfaces of the aforementioned metal dampers at a position at an inner diameter side from the joined portion, and is unitized with the pair of pressing members being connected in a state in which they sandwich the metal damper.

Mechanism for restraining fuel pressure pulsation and high pressure fuel supply pump of internal combustion engine with such mechanism

PROBLEM TO BE SOLVED: To provide a device which can be used in a fuel system having a variable supply pressure and has a small structure and a long lifetime. SOLUTION: There are provided with a housing 38 and 40, and a working chamber 66. The working chamber 66 is communicated with a hydraulic system. At least one gas capacity 58, which is tightly closed with a diaphragm 54, is formed in the working chamber 66. COPYRIGHT: (C)2004,JPO

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Papers

Device for damping pressure pulsation within hydraulic system

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Papers

Device for damping pressure pulsation within hydraulic system

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