Hitachi Automotive Systems, Ltd.

Hitachi, Ltd.

Other

Tomoegawa Paper Co., Inc.

Hitachi Astemo Ltd.

Katsumi Miyazaki

Satoshi Usui

Shingo Tamura

Hiroyuki Yamada

Kenichiro Tokuo

Tatsuo Kawano

Masayuki Suganami

Minoru Hashida

Masahiko Hayatani

Sunao Takahashi

Yasuo Kobayashi

Shunsuke Aritomi

Akinori Sei

Churyo Kodama

Masami Yanagisawa

Yasuo Hirasawa

Takao Higashi

Yukio Takahashi

Fumio Kawamura

Kenichirou Tokuo

Taisuke Hirota

Naoki Hagiwara

Daisuke Suetsugu

Hitoshi Konno

Yuka Sugata

A high pressure fuel pump includes a pump housing, pressure and damper chambers, a metal diaphragm, a press-fitted portion, and a weld portion. The pressure chamber is provided in the pump housing. The damper chamber is formed by the pump housing and a damper cover. The metal diaphragm damper is arranged in the damper chamber. At the press-fitted portion, an annular surface of the damper cover is press fitted to an annular surface of the pump housing. The weld portion fixes the damper cover to the pump housing at an entire circumference of the press-fitted portion.

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

A fuel pump includes an intake valve unit which is provided between a low-pressure chamber and a pressurizing chamber. The intake valve unit includes an intake valve configured to move in an axial direction of the intake valve unit and a valve stopper arranged between the intake valve and the pressurizing chamber. A plurality of fuel passages configured to allow fuel to communicate between the low-pressure chamber and the pressurizing chamber are formed on a radially outward of an outer peripheral surface of the valve stopper.

High-pressure fuel supply pump having electromagnetically-driven intake valve

A high-pressure fuel supply pump includes a pressurizing chamber, a piston plunger, and an electromagnetically-driven intake valve mechanism. The piston plunger reciprocates within the pressurizing chamber. The electromagnetically-driven intake valve mechanism is provided at an inlet of the pressurizing chamber. The electromagnetically-driven intake valve mechanism includes an anchor which pulls a plunger rod, a fixed core which attracts the anchor, and a yoke in which inner peripheral part has the fixed core and the anchor. The fixed core is fixed to a bottom part of the yoke. A through hole is formed at a bottom part of the fixed core.

To reduce collision noise created by the operation of an electromagnetic suction valve provided on a high pressure fuel supply pump, the mass of a member which collides by magnetic attractive force is reduced. The noise generated when a core and an anchor collide with each other by magnetic attractive force depends on the magnitude of the kinetic energy of a moving element. The kinetic energy to be consumed in the collision is only the kinetic energy of the anchor. The kinetic energy of a rod, being absorbed by a spring, does not contribute to the noise; thus, the energy when the anchor and the core collide with each other can be reduced, whereby the noise to be created can be reduced.

High pressure fuel supply pump with electromagnetic suction valve

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. Gas is sealed in the aforementioned hermetically sealed space of the damper, and a pair of pressing members give pressing forces to both outer surfaces of the aforementioned metal dampers at a position at an inner diameter side from the joined portion. The mechanism is unitized, with the pair of pressing members being connected in a state in which they sandwich the metal damper.

To reduce collision noise created by the operation of an electromagnetic suction valve provided on a high pressure fuel supply pump. In the present invention, in order to achieve the above object, the mass of a member which collides by magnetic attractive force is reduced to reduce the noise to be generated. The thus configured present invention provides the following advantageous effects. The noise generated when a core and an anchor collide with each other by magnetic attractive force depends on the magnitude of the kinetic energy of a moving element. The kinetic energy to be consumed in the collision is only the kinetic energy of the anchor. The kinetic energy of a rod, being absorbed by a spring, does not contribute to the noise; thus, the energy when the anchor and the core collide with each other can be reduced, whereby the noise to be created can be reduced.

It is an object of the present invention to provide an electromagnetic valve structure improved in terms of the responsiveness of the electromagnetic valve and helping to realize a more accurate flow rate control, and to provide a high-pressure fuel supply pump in which the same is mounted. There is provided a high-pressure fuel supply pump having an electromagnetic valve equipped with an electromagnetic coil generating an electromagnetic force for opening and closing a valve body provided between a fuel intake path and a pressure chamber, a movable member operated by the electromagnetic force, a housing accommodating the movable member, and a back-pressure chamber formed between the housing and the movable member, wherein a first fuel path causing the back-pressure chamber to communicate with the intake path passes the center axis of the movable member.

High-pressure fuel supply pump

Responsiveness is improved in valve opening and valve closing of an electromagnetically driven intake valve unit in which a valve is provided on a pressurizing chamber side of a valve seat. The valve includes an annular abutting surface that abuts the valve seat to shut off a fuel intake passage and a bottomed cylindrical part provided at an inner peripheral part of the annular abutting surface. The bottomed cylindrical part is inserted into a fuel introduction hole formed in the valve housing inside the valve seat, and the outer surface of an end part of the bottomed cylindrical part is exposed to fuel in a low pressure fuel chamber provided upstream of the fuel introduction hole.

A high-pressure fuel pump includes a pump housing formed with a recess, a cylinder combined with the pump housing to define the recess as a pressurizing chamber, a holder securing the cylinder to the pump housing, and a plunger sliding against the cylinder to pressurize fluid in the pressurizing chamber. The holder includes an outer cylindrical surface portion fitted to an attachment fitting hole of an engine block of an internal combustion engine, and a cylindrical fitting portion fitted to an outer circumference of the cylinder. The outer cylindrical surface portion and the cylindrical fitting portion are formed in a single piece resulting from machining one and the same member.

High-pressure fuel pump assembly mechanism

The present invention eliminates a valve holder and accommodates a valve guide in a small space provided between a valve seat and a peripheral surface part of a pressure chamber to reduce the size of a pump. The valve guide guides a stroke of the valve and is provided inside the valve seat. The valve includes an annular abutting surface that abuts a valve seat formed in a valve housing to shut off a fuel intake passage and a bottomed cylindrical part is provided at an inner peripheral part of the annular abutting surface. The bottomed cylindrical part is inserted into a fuel introduction hole formed in the valve housing inside the valve seat. A member having a cylindrical surface part that supports a reciprocating motion of the valve, is fixed to the valve housing, face-to-face with an inner peripheral part of the bottomed cylindrical part.

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.

Growing community of inventors

Hitachinaka, Japan

Katsumi Miyazaki