Denso Corporation

Ryo Katsura

Kenji Funai

Toshihiko Igashira

Satoshi Hayashi

Yutaka Yamada

Ken Mizutani

An ECU estimates a variation amount of fuel which is actually suctioned by a fuel pump based on a fuel pressure in a common rail. Even though the fuel pressure in the common rail deviates from a target fuel pressure, when the estimated variation amount of fuel is substantially zero, an energization quantity to a solenoid of a flow control valve is compulsorily reduced.

Fuel pressure controller and fuel pressure control system

A fuel injector for an internal combustion engine is provided. The fuel injector has a simple structure so that it is easy to install and remove a piezoelectric valve actuator in and from the fuel injector, and to adjust fuel injection characteristics finely which allows the overall size of the fuel injector to be decreased. The fuel injector includes a housing to be installed in the engine and a structural element serving to install the piezoelectric valve actuator in the housing to be detachable easily. The piezoelectric valve actuator is retained in an actuator casing fitted in the housing so that it can expand or contract to move a needle valve. The actuator casing has an extensible portion in itself or is coupled to a bellows in alignment for enabling the piezoelectric valve actuator to expand, thereby allowing the size of the actuator casing to be minimized.

Structure of fuel injector using piezoelectric actuator

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.

Growing community of inventors

Kariya, Japan

Ryo Katsura