Denso Corporation

Nippondenso Co., Ltd.

Satoshi Hayashi

Toshihiko Igashira

Masahiro Tomita

Takehiro Watarai

Yoshinobu Takeuchi

Shinro Oda

Masatoshi Kuroyanagi

Tomoo Kawase

Kazuhiko Miura

Naoyuki Kawazoe

Hitoshi Niwa

Tomoyuki Kanda

Hirokatsu Mukai

Kenji Funai

Kenzi Kato

Ryo Katsura

Akira Fujii

Junji Moriwaki

Katuhide Akimoto

Masayoshi Tanigawa

A supplying unit supplies energy to an actuator so that the supplied energy is kept therein, making displacement the actuator. An interrupting unit interrupts the supply of energy to cause the actuator to discharge the kept energy, making displacement the actuator. A converting unit is adapted to convert the displacement of the actuator corresponding to the kept energy into hydraulic pressure applied to the valve member, moving the valve member to open the low pressure port and close the high pressure port. The convert unit converts the displacement of the actuator corresponding to the discharged energy into hydraulic pressure applied to the valve member, moving the valve member to open the high pressure port and close the low pressure port. Energy which the actuator requires to move the valve member so as to close the high pressure port is larger than energy which the actuator requires to move the valve member so as to open the low pressure port.

Hydraulic control device, system and method for controlling actuator device

A hydraulic control valve for a fuel injector for an automotive engine, which includes a piezoelectric actuator and a hydraulic valve mechanism. The hydraulic valve mechanism converts a mechanical deformation of the piezoelectric actuator produced as a result of application of a voltage into a hydraulic pressure to move a valve member for opening and closing a fluid port. The hydraulic valve mechanism is so designed that the piezoelectric actuator produces a maximum output force which works to develop the hydraulic pressure when opening the fluid port through the valve member and decreases after the fluid port is opened and which is set smaller than one-half of a maximum possible output force of the piezoelectric actuator under application of a maximum working voltage to said piezoelectric actuator, thereby ensuring a maximum movement of the valve member at high energy efficiency under application of the voltage within a working voltage range.

Hydraulic control valve and fuel injector using same

A fuel injector is provided which is designed to suppress unwanted vibrations of a nozzle needle-actuating piston, thereby avoiding the injection of an excess quantity of fuel. The fuel injector comprises an actuator and a displacement amplifying chamber filled with fluid to which a large-diameter piston and a small-diameter piston working as the nozzle needle-actuating piston are exposed. The displacement amplifying chamber works to amplify and transmit displacement of the large-diameter piston by the actuator to the small-diameter piston. The fuel injector also includes a stopper which restricts movement of the small-diameter piston toward the displacement amplifying chamber to a given range, thereby suppressing the unwanted vibrations of the small-diameter piston.

Structure of fuel injector for avoiding injection of excess quantity of fuel

A valve actuating device is provided which may be employed in fuel injectors for automotive internal combustion engines. The valve actuating device includes an actuator, a large-diameter piston displaced by said actuator, a small-diameter piston operating a valve, a displacement amplifying chamber filled with working fluid to amplify and transmit displacement of the large-diameter piston to the small-diameter piston, and a drain passage. The drain passage communicates with the displacement amplifying chamber through a pinhole for draining the working fluid within the displacement amplifying chamber, thereby enabling the pressure in the displacement amplifying chamber to be released in order to ensure the movement of the small-diameter piston when the valve actuating device is started.

Valve actuating device and fuel injector using same

A stacked-type piezoelectric device to be built in an injector includes a metal case outside its side surfaces. An insulating member having an electric insulation property is interposed between the side surfaces of the piezoelectric device and an inner surface of the case . The insulating member is bonded to either the side surfaces of the piezoelectric device or the inner surface of the case, and at least a part of the insulating member is in contact with the other surface.

Piezoelectric device for injector, method for producing the same, and injector

Structure of angular rate sensor

An angular velocity detector includes vibrator made of piezoelectric material and having a pair of arms. A pair of driving electrodes are attached to the arms in order to generate vibrations in the arms. A pair of detecting electrodes, which are attached to the arms, detect the vibrations of the arms. Therefore, the pair of driving electrodes can cause the arms to vibrate uniformly and stably, so that a S/N ratio of the angular velocity sensor can be improved.

Angular velocity sensor

According to the present invention there is provided a piezoelectric type actuator wherein a compressive force is exerted on a piezoelectric laminate, using a coil spring having a relatively small spring constant and a coned disc spring having a relatively large spring constant, the said compressive force being in the range of 4.0 to 50 in terms of the ratio of the spring constant of the coned disc spring to that of the coil spring. Under the above construction, the performance of the piezoelectric laminate is not deteriorated under any conditions during use, and the size of the piezoelectric type actuator can be reduced.

Piezoelectric type actuator

A pilot injection system according to the present invention, which is used in a fuel injection pump, has a casing attached to the pump. The casing connects internally with a pump chamber of the injection pump. A partition wall is fixed in the casing, whereby the pump chamber is divided from the inside of the casing. A movable wall, which is movably located in the casing, divides the inside space of the casing between a fuel-spill chamber and a holding chamber. The partition wall is formed with a valve hole, which connects the pump chamber and the spill chamber. The valve hole has a seat surface which faces the pump chamber. A valve plug, which is located in the pump chamber, can be seated on the seat surface. The valve plug is connected to the movable wall by means of a coupling rod, which extends through the valve hole. Located in the spill chamber is a return spring which urges the movable wall in a direction such that the valve plug closes the valve hole. Moreover, an actuator for moving the movable wall is disposed in the holding chamber of the casing. The actuator includes a stack of piezoelectric elements, which can extend or contract in accordance with a voltage applied thereto.

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Kuwana, Japan

Satoshi Hayashi