Hitachi, Ltd.

Kohei Itoh

Norikazu Matsuzaki

Masaru Ito

Shinya Imura

Hidekazu Moriki

Yuuichirou Takamune

Shin Fujiwara

In a four-wheel drive vehicle, front wheelsL andR are driven by an engine, and rear wheelsL andR are driven by an electric motor. A high-power alternatoris driven by the engine, and electric power generated from the alternatordrives the motor. In addition to controlling the power generation of the high-power alternatorand the driving of the motor, a 4WD CUestimates an induced voltage E of the motorfrom a voltage MHV of the motor and from an output current Ia of the high-power alternator, and estimates a rotating speed Nm of the motor from estimation results on the induced voltage E.

Vehicle driving system

In a control apparatus for a vehicle having an electric motor for driving the wheels of the vehicle, an electric power source for energizing the electric motor, a motor torque target value calculation unit for controlling the electric power source, and a field current target value calculation unit, the motor field current is momentarily decreased when the difference between the actual motor armature current and the motor armature current target value exceeds a predetermined value or when the wheels are deemed to slip, and the motor field current is increased as the actual armature current of the motor substantially follows the motor armature current target value.

Control apparatus for vehicle

A differentiator calculates the acceleration of the rear wheels. An acceleration threshold calculation means enable the skid-detection acceleration threshold to be adjusted corresponding to the conditions of the vehicle. An acceleration skid-detection means make a comparison between the acceleration of the wheels obtained by the differentiator and the skid-detection acceleration threshold adjusted by the acceleration threshold calculation means, and determine whether or not a skid of the wheels has occurred, based upon the comparison result. Such an arrangement provides a vehicle driving force system having a function of detecting a skid even in a case that a skid of the wheels has occurred at a low acceleration of the vehicle.

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Hitachiohta, Japan

Kohei Itoh