Patent ID: 7048084

Claim:
A power distribution control apparatus of a four-wheel drive vehicle equipped with a power source, the vehicle having front wheels and rear wheels, and a transmitting device, wherein the front wheels and the rear wheels are driven by the power source, and the transmitting device is capable of changing distribution of power to the front wheels and the rear wheels, wherein the control apparatus selects one of at least a first drive mode and a second drive mode according to a driving state of the vehicle, and the control apparatus controls the transmitting device such that the power distribution to the front wheels and the rear wheels is a ratio that corresponds to the selected drive mode, and wherein an power distribution to the front wheels and the rear wheels is closer to the equalized state in the second drive mode than in the first drive mode, the control apparatus comprising: storing means that in advance stores a threshold value map used for setting a threshold value related to an angular velocity of a steering wheel of the vehicle, wherein the threshold value map is a three-dimensional map that uses a vehicle speed and an angle of the steering wheel as parameters; and determining means, wherein, based on the threshold value map, a determining means sets the threshold value according to a current vehicle speed and the steering wheel angle, wherein, when the current steering wheel angular velocity is not greater than the set threshold value, the determining means selects the first drive mode, and wherein, when the current steering wheel angular velocity is greater than the set threshold value, the determining means selects the second drive mode, wherein the threshold value map is configured such that the threshold value is decreased as the vehicle speed is increased and that threshold value is greater in a predetermined small steering wheel angle region than in a steering wheel angle region that corresponds to greater values of the steering wheel angle than the small steering wheel angle region.