Abstract: In a power distribution control system for a four-wheel-drive vehicle, a 4WD controller is electronically connected to a friction clutch for controlling a torque distribution ratio. The 4WD controller determines whether a past-history condition, a command torque, and a reversal-of-torque condition that an input direction of torque inputted into the friction clutch is reversed is satisfied. The 4WD controller outputs a countermeasure-of-noise command torque decreased from the current command torque as a command signal for the friction clutch, when the past-history condition, the command torque condition, and the reversal-of-torque condition are all satisfied.

Abstract: The present invention provides an apparatus for estimating clutch temperature estimates clutch temperatures that closely follow actual clutch temperature without a temperature sensor and at low cost. The apparatus employs method for calculating energy applied to the driving clutch according to the detected rotational speed difference and estimated torque and method for estimating a clutch temperature variation based on the calculated energy and estimating a clutch temperature based on the estimated clutch temperature variation.

Abstract: In a power distribution control system for a four-wheel-drive vehicle, a 4WD controller is electronically connected to a friction clutch for controlling a torque distribution ratio. The 4WD controller determines whether a past-history condition that a clutch input torque has been greater than or equal to a predetermined threshold value is satisfied when a command torque is greater than or equal to the predetermined threshold value, and determines whether a command torque condition that a current command torque is greater than or equal to the predetermined threshold value is satisfied, and also determines whether a reversal-of-torque condition that an input direction of torque inputted into the friction clutch is reversed is satisfied. The 4WD controller outputs a countermeasure-of-noise command torque decreased from the current command torque as a command signal for the friction clutch, when the past-history condition, the command torque condition, and the reversal-of-torque condition are all satisfied.

Abstract: A forward and aft torque distribution system and a method of controlling forward and aft torque distribution for a four-wheel vehicle having an electronically controlled clutch to control split of drive torque to be transferred to front and rear wheels are disclosed. A 4WD controller is responsive to mode selection signals from a mode changeover switch and a vehicle speed signal delivered from a vehicle speed sensor, and has control modes involving at least a LOCK mode and an AUTO mode. When the vehicle speed becomes less than a vehicle's halt discriminative vehicle speed indicative of a vehicle's halt state during the LOCK mode, the controller allows the electronically controlled clutch to be released.

Abstract: The present invention provides an apparatus for estimating clutch temperature estimates clutch temperatures that closely follow actual clutch temperature without a temperature sensor and at low cost. The apparatus employs method for calculating energy applied to the driving clutch according to the detected rotational speed difference and estimated torque and method for estimating a clutch temperature variation based on the calculated energy and estimating a clutch temperature based on the estimated clutch temperature variation.

Abstract: To achieve a first object of the present invention, a starting time limit vehicle speed which preferentially permits a torque distribution to front and rear wheels at the time of starting of a vehicle is switched in accordance with a degree of a diameter difference. To achieve a second object of the present invention, when the vehicle makes a normal running with different-diameter tires mounted thereon, a front/rear wheel distribution torque caused by a front/rear wheel rotation speed difference owing to the different-diameter tires is limited by switching a torque gain depending on a degree of a diameter difference.

Abstract: A forward and aft torque distribution system and a method of controlling forward and aft torque distribution for a four-wheel vehicle having an electronically controlled clutch to control split of drive torque to be transferred to front and rear wheels are disclosed. A 4WD controller is responsive to mode selection signals from a mode changeover switch and a vehicle speed signal delivered from a vehicle speed sensor, and has control modes involving at least a LOCK mode and an AUTO mode. When the vehicle speed becomes less than a vehicle's halt discriminative vehicle speed indicative of a vehicle's halt state during the LOCK mode, the controller allows the electronically controlled clutch to be released.

Abstract: To achieve a first object of the present invention, a starting time limit vehicle speed which preferentially permits a torque distribution to front and rear wheels at the time of starting of a vehicle is switched in accordance with a degree of a diameter difference. To achieve a second object of the present invention, when the vehicle makes a normal running with different-diameter tires mounted thereon, a front/rear wheel distribution torque caused by a front/rear wheel rotation speed difference owing to the different-diameter tires is limited by switching a torque gain depending on a degree of a diameter difference.