Control device for four-wheel drive vehicle

摘要

When there is a curve in a forward driving path of a vehicle, a wheel clutch for a turning outer wheel of a rear shaft is engaged and a wheel clutch for a turning inner wheel of the rear shaft is disengaged during driving of the curve. When there is no curve, both of the right and left wheel clutches are engaged when it is estimated the vehicle receive a predetermined disturbance input during forward driving. Then, a target yaw moment of a vehicle is calculated. If an average speed of the right and left wheels of a front shaft is more than the speed of the turning outer wheel, the wheel clutch for the turning outer wheel is engaged when the target yaw moment is applied to the vehicle, so that the engaging force of a transfer clutch is controlled based on the target yaw moment.

主权项

1. A control device for a four-wheel drive vehicle comprising:
a driving force distributor provided between a main drive shaft, which is either one of a front shaft and a rear shaft, and a sub-drive shaft, which is the other one of the front and rear shafts, the driving force distributor being configured to variably change driving force distribution between the main drive shaft and the sub-drive shaft; a clutch provided on the sub-drive shaft to engage and disengage transmission of driving force to each of a left wheel and a right wheel, instead of a differential mechanism between the right and left wheels, a forward driving state estimator to estimate a forward driving state of a vehicle by recognizing a forward driving path of the vehicle; a clutch controller to control the engagement and disengagement of the right and left clutches of the sub-drive shaft based on at least the forward driving state of the vehicle estimated by the forward driving state estimator; and a driving force distribution controller to calculate, as a target yaw moment, a yaw moment which is applied to the vehicle based on an operation state of the vehicle, and control the driving force distributor based on the target yaw moment, wherein, when an average speed of right and left wheels of the main drive shaft is not more than a speed of a turning outer wheel of the sub-drive shaft, the driving force distribution controller sets the driving force distribution for the sub-drive shaft to zero.