Hitachi Automotive Systems, Ltd.

Hitachi, Ltd.

Fumiaki Nasu

Takuya Mayuzumi

Mitsuhiko Watanabe

Akira Mishima

Ayumu Hatanaka

Mamoru Okuda

Chikara Oomori

Kohei Onda

At the time of drop of an injector current of an internal combustion engine controller, the drop is performed quickly while heat generation of a drive circuit is suppressed, and valve closing response speed of the injector is enhanced. The internal combustion engine controller includes a drive circuit which drives an injector current, and a boost circuit which boosts a battery voltage, and includes a peak current path for guiding a boost voltage of the boost circuit to an upstream side of the injector via a boost side switching element and a boost side protection diode, a holding current path for guiding the battery voltage to the upstream side of the injector via a battery side switching element and a battery side protection diode, a ground current path which is connected to a power supply ground from a downstream side of the injector via a downstream side switching element, and a regenerating circuit which allows the boost circuit to regenerate electric energy of the injector from the downstream side of the injector via a current regenerating diode, wherein the regenerating path is provided with a voltage regulating section in series with the current regenerating diode, and the drive circuit controls drive of the switching element.

Internal combustion engine controller

Disclosed is an electromagnetic valve driving circuit capable of reducing a load of a booster circuit. A boost driving FETis connected to a route formed between the booster circuitand a first terminal of an injector. A battery-side driving FETand a battery protection diode Db are connected to a route formed between a positive-polarity side of a power supply and the first terminal of the injector. A freewheeling diode Df is connected at a first terminal thereof to a portion between the first terminal of the injectorand the battery protection diode Db, and at a second terminal thereof to a grounding side of the power supply. An injector downstream-side driving FETis connected to a route formed between the second terminal of the injectorand the grounding side of the power supply. In addition to operating the FETs, andaccording to a level of a current which flows through the injector, a control circuitactivates the battery-side driving FETduring a period in which the boost driving FETrepeatedly turns on and off a plurality of times.

Electromagnetic valve driving circuit

The present invention realizes an injector drive circuit capable of providing high output power of a boost convertor while suppressing increases in size and cost thereof. An injector energizing circuitincludes an FETwhich applies a high voltagegenerated by a boost convertorto an injection valve. The boost convertorincludes an input side capacitor, a boosting FET, a boost coil, a boost diode, and FETsandprovided in association with a negative pole of an output side capacitor. During a period in which the high voltageis applied to the injection valve, a gate signalof the FETis turned ON and a gate signalof the FETis turned OFF. Consequently, the boosting FETperforms a switching operation to turn OFF the gate signalof the FETand turn ON the gate signalof the FETduring a period for charging into the output side capacitor. Thus, energy required for boosting can be reduced and an improvement in output is enabled.

Injector drive circuit

A fuel injection valve driving method includes control of an overexciting current and a holding current supplied to the fuel injection valve in accordance with a target fuel supply pressure as obtained from an operating condition. Thereby the opening and holding of the open position of the fuel injection valve is controlled.

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Hitachinaka, Japan

Fumiaki Nasu