Nippondenso Co., Ltd.

Fuyuky Maehara

Hidetoshi Kato

Nobuo Mayumi

A voltage regulator maintains an output voltage of an alternator of a vehicle to a voltage in the vicinity of a preset voltage. The voltage regulator has a microcomputer for setting the OFF duty ratio, a switching circuit for switching on or off an electric current flowing through a rotor coil of the alternator and a load sensor for detecting the operation of the intermittent load. The microcomputer sets the OFF duty ratio to a value directly proportional to the difference between the output voltage and the preset voltage before the operation of the intermittent load is started. And the microcomputer gradually decreases the OFF duty ratio set by said duty ratio setting means at the initial operation time of the intermittent load, and memorizes the OFF duty ratio when the output voltage reaches its upper limit value exceeding the preset voltage. The microcomputer changes the OFF duty ratio to an average value of the OFF duty ratio set by the duty ratio setting means and the OFF duty ratio memorized by the memory means when the reoperation of the intermittent load is detected within a prescribed time after the initial operation of the intermittent load.

Voltage regulator for alternator of vehicle

The battery voltage regulating system for vehicle use of this invention controls the energization of an alternating-current generator by a generation control circuit responsive to a battery voltage in normal operation. However, if a fault condition such as the damage of a resistor of the generation control circuit or a break in the warning line occurs, and even if the resulting warning is ignored or over-looked by the driver, a warning control circuit provided a requisite control to regulate the generator's generation while giving a warning. In this manner, an average voltage of a battery is kept substantially equal to a predetermined constant value controlled by said generation control circuit even if such unexpected situation occurs. Thus, the battery voltage regulating system can prevent the battery from being excessively charged.

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Kariya, Japan

Fuyuky Maehara