Drive-force distribution controller and drive-force distribution method for four-wheel-drive vehicle

A drive-force distribution controller for a four-wheel-drive vehicle equipped with a drive-force transmission apparatus which transmits drive force to rear wheels or front wheels of the vehicle in accordance with a designated drive-force transmission ratio, comprising:

• vehicle-speed detection means for detecting vehicle speed;
• throttle-opening detection means for detecting opening of a throttle valve of an engine of the vehicle;
• and
• throttle-open-speed calculation means for calculating throttle open speed on the basis of the throttle opening detected by the throttle-opening detection means, wherein
• the drive-force distribution controller changes the drive-force transmission ratio of the drive-force transmission apparatus on the basis of not only the detected vehicle speed and the detected throttle opening, but also the calculated throttle open speed.

A drive-force distribution method for a four-wheel-drive vehicle equipped with a drive-force transmission apparatus which transmits drive force to rear wheels or front wheels of the vehicle in accordance with a designated drive-force transmission ratio, comprising:

• detecting vehicle speed and opening of a throttle valve of an engine of the vehicle;
• calculating throttle open speed on the basis of the detected throttle opening;
• and
• changing the drive-force transmission ratio of the drive-force transmission apparatus on the basis of not only the detected vehicle speed and the detected throttle opening, but also the calculated throttle open speed.

A drive-force distribution controller for a four-wheel-drive vehicle equipped with a drive-force transmission apparatus which transmits drive force to rear wheels or front wheels of the vehicle in accordance with a designated drive-force transmission ratio, comprising:

• vehicle-speed detection means for detecting vehicle speed;
• throttle-opening detection means for detecting opening of a throttle valve of an engine of the vehicle;
• command torque calculation means for calculating a command torque on the basis of the vehicle speed detected by the vehicle-speed detection means and the throttle opening detected by the throttle-opening detection means, the command torque representing a torque to be distributed to the front wheels or the rear wheels;
• and
• command current calculation means for calculating a command current to he supplied to the drive-force transmission apparatus, on the basis of the command torque calculated by the command torque calculation means,
• the drive-force distribution controller supplying the command current to the drive-force transmission apparatus in order to variably control the drive-force transmission ratio of the drive-force transmission apparatus, wherein
• the command current calculation means determines a command current filter value on the basis of the vehicle speed detected by the vehicle-speed detection means and a command current filter map stored in storage means and providing a command current filter value which changes in accordance with the vehicle speed, and adjusts the change speed of the command current in accordance with the determined command current filter value.

A drive-force distribution method for a four-wheel-drive vehicle equipped with a drive-force transmission apparatus which transmits drive force to rear wheels or front wheels of the vehicle in accordance with a designated drive-force transmission ratio, comprising:

• detecting vehicle speed and opening of a throttle valve of an engine of the vehicle;
• calculating a command torque on the basis of the detected vehicle speed and the detected throttle opening, the command torque representing a torque to be distributed to the front wheels or the rear wheels;
• and
• calculating a command current to be supplied to the drive-force transmission apparatus, on the basis of the calculated command torque;
• and
• supplying the command current to the drive-force transmission apparatus in order to variably control the drive-force transmission ratio of the drive-force transmission apparatus, wherein
• the step of calculating a command current comprises determining a command current filter value on the basis of the detected vehicle speed and a command current filter map providing a command current filter value which changes in accordance with the vehicle speed, and adjusting the change speed of the command current in accordance with the determined command current filter value.