Power distribution control apparatus for four-wheel drive vehicle and a method for contolling the apparatus

摘要

A power distribution control apparatus determines a command value that corresponds to the driving state of a four-wheel drive vehicle. The vehicle includes a pair of front wheels (5a,5b) and a pair of rear wheels (11a,11b), and a coupling device (7) that changes the power distribution to the front wheels and the rear wheels. The control apparatus (21) detects the differential rotation speed between the average rotation speed of the front wheels and the average rotation speed of the rear wheels. The control apparatus estimates the exothermic energy generated in the coupling device (7) based on the product of the differential rotation speed and the command value. The control apparatus determines an optimum drive mode for the four-wheel drive vehicle based on the estimated exothermic energy and for selecting map data corresponding to the determined drive mode. The control apparatus determines the command value that corresponds to the driving state by using the map data.