Abstract: A drive force transmission apparatus is mountable on a four-wheel drive vehicle switchable between a four-wheel drive mode that transmits a drive force of an engine to front wheels and rear wheels, and a two-wheel drive mode that transmits the drive force to only the front wheels. The drive force transmission apparatus allows adjustment of the drive force to the rear wheels, and includes a multi-plate clutch, a piston for axially pressing the multi-plate clutch, an actuator for axially moving the piston, and a control unit for controlling the actuator. Upon satisfaction of a predetermined condition that indicates a high probability of the vehicle needing to be switched from the two-wheel drive mode to the four-wheel drive mode, the control unit causes the actuator to displace the piston by a predetermined amount with respect to an initial position of the piston toward the multi-plate clutch.

Abstract: A control device is mounted on a four-wheel-drive vehicle, and includes a detector and a vibration suppression controller. The detector detects the occurrence of a vibrating state, in which drive wheels and auxiliary drive wheels slip alternately in a four-wheel-drive state in which a drive force is transferred to the auxiliary drive wheels, or the occurrence of a preliminary state for the vibrating state. The vibration suppression controller reduces the drive force which is transferred to the auxiliary drive wheels via a drive force transfer device when the vibrating state or the preliminary state is detected by the detector. The vibration suppression controller reduces the drive force which is transferred to the auxiliary drive wheels on condition that a thermal load of the drive force transfer device is less than a predetermined threshold.

Abstract: A control apparatus for a four-wheel drive vehicle includes a current detector configured to output a detection signal in accordance with the magnitude of an actual control current, a target current value calculator configured to calculate a target current value that is a target value of the control current, and a current controller configured to control a current output circuit to output the control current having the target current value calculated by the target current value calculator based on a result of detection performed by the current detector. When the four-wheel drive vehicle is in a two-wheel drive mode in which first and second friction clutches are released, the current controller performs zero-point adjustment for adjusting a zero point of the control current to be output from the current output circuit.

Abstract: A controller for a driving force transmitting apparatus mounted in a four-wheel-drive vehicle, includes: a driving force controller configured to calculate a command torque indicating a driving force to be transmitted to the sub-drive wheels via the driving force transmitting apparatus based on a traveling state of the four-wheel-drive vehicle and a road surface condition, and to control the driving force transmitting apparatus based on the command torque; and a road surface condition determiner configured to determine that the road surface condition is a high-? condition when a duration of a non-slipping state where a vehicle speed is equal to or higher than a prescribed value and a slip ratio of each of both the main drive wheels is lower than a prescribed value has become equal to or longer than a prescribed time.

Abstract: A control device mounted on a four-wheel drive vehicle includes: a slip ratio calculating unit that obtains a slip ratio of main driving wheels based at least on wheel speeds; a smoothing unit that smooths the slip ratio by filtering; and a driving force control unit that controls a driving force transmission device so that a driving force that is transmitted to auxiliary driving wheels increases as the slip ratio smoothed by the smoothing unit increases.

Abstract: A drive force transmission apparatus is mountable on a four-wheel drive vehicle switchable between a four-wheel drive mode that transmits a drive force of an engine to front wheels and rear wheels, and a two-wheel drive mode that transmits the drive force to only the front wheels. The drive force transmission apparatus allows adjustment of the drive force to the rear wheels, and includes a multi-plate clutch, a piston for axially pressing the multi-plate clutch, an actuator for axially moving the piston, and a control unit for controlling the actuator. Upon satisfaction of a predetermined condition that indicates a high probability of the vehicle needing to be switched from the two-wheel drive mode to the four-wheel drive mode, the control unit causes the actuator to displace the piston by a predetermined amount with respect to an initial position of the piston toward the multi-plate clutch.

Abstract: A control apparatus for a four-wheel drive vehicle includes a current detector configured to output a detection signal in accordance with the magnitude of an actual control current, a target current value calculator configured to calculate a target current value that is a target value of the control current, and a current controller configured to control a current output circuit to output the control current having the target current value calculated by the target current value calculator based on a result of detection performed by the current detector. When the four-wheel drive vehicle is in a two-wheel drive mode in which first and second friction clutches are released, the current controller performs zero-point adjustment for adjusting a zero point of the control current to be output from the current output circuit.

Abstract: A controller for a driving force transmitting apparatus mounted in a four-wheel-drive vehicle, includes: a driving force controller configured to calculate a command torque indicating a driving force to be transmitted to the sub-drive wheels via the driving force transmitting apparatus based on a traveling state of the four-wheel-drive vehicle and a road surface condition, and to control the driving force transmitting apparatus based on the command torque; and a road surface condition determiner configured to determine that the road surface condition is a high-? condition when a duration of a non-slipping state where a vehicle speed is equal to or higher than a prescribed value and a slip ratio of each of both the main drive wheels is lower than a prescribed value has become equal to or longer than a prescribed time.

Abstract: A control device mounted on a four-wheel drive vehicle includes: a slip ratio calculating unit that obtains a slip ratio of main driving wheels based at least on wheel speeds; a smoothing unit that smooths the slip ratio by filtering; and a driving force control unit that controls a driving force transmission device so that a driving force that is transmitted to auxiliary driving wheels increases as the slip ratio smoothed by the smoothing unit increases.

Abstract: A control device is mounted on a four-wheel-drive vehicle, and includes a detector and a vibration suppression controller. The detector detects the occurrence of a vibrating state, in which drive wheels and auxiliary drive wheels slip alternately in a four-wheel-drive state in which a drive force is transferred to the auxiliary drive wheels, or the occurrence of a preliminary state for the vibrating state. The vibration suppression controller reduces the drive force which is transferred to the auxiliary drive wheels via a drive force transfer device when the vibrating state or the preliminary state is detected by the detector. The vibration suppression controller reduces the drive force which is transferred to the auxiliary drive wheels on condition that a thermal load of the drive force transfer device is less than a predetermined threshold.

Abstract: A driving force distribution controller comprises: a control device determining the value of torque which must be transmitted to a rear wheel; and a driving force transmission device transmitting torque corresponding to the torque value determined by the control device to the rear wheel. The control device reduces a torque value calculated based on an opening degree of an accelerator and a rotational speed difference when the rotational speed of an engine is lower than a first threshold value but higher than a second threshold value.

Abstract: Discloses is a method of controlling a four-wheel drive vehicle equipped with a torque distribution device capable of changing a torque distribution amount for secondary driven wheels according to an input current to be applied thereto. This method comprises the steps of: applying, to the torque distribution device, a current value corresponding to a target torque distribution amount; and, performing a current changing control for increasing and reducing the input current to the torque distribution device. The step of performing a current changing control includes causing the input current to the torque distribution device to be temporarily increased to a value greater than the current value corresponding to the target torque distribution amount, and then returned to the current value corresponding to the target torque distribution amount, and repeating the temporary increasing of the input current at least at intervals of a predetermined time.

Abstract: A driving force distribution controller comprises: a control device determining the value of torque which must be transmitted to a rear wheel; and a driving force transmission device transmitting torque corresponding to the torque value determined by the control device to the rear wheel. The control device reduces a torque value calculated based on an opening degree of an accelerator and a rotational speed difference when the rotational speed of an engine is lower than a first threshold value but higher than a second threshold value.

Abstract: A driving force distribution control device controls an inductive load circuit to adjust a ratio of driving forces transmitted from a driving source to a plurality of wheels via a driving force transmitting system. The driving force distribution control device counts a number of tests performed by applying a test current to the inductive load circuit; determines that a disconnecting abnormality occurs in an electric load including the inductive load circuit if a difference between a value of the test current and a value of current flowing in the inductive load circuit is greater than a current difference threshold value; and determines that the disconnecting abnormality is definitive if the number of tests is equal to a threshold value or more, and also if the number of determinations of the disconnecting abnormality is equal to a predetermined threshold value or more.

Abstract: Discloses is a method of controlling a four-wheel drive vehicle equipped with a torque distribution device capable of changing a torque distribution amount for secondary driven wheels according to an input current to be applied thereto. This method comprises the steps of: applying, to the torque distribution device, a current value corresponding to a target torque distribution amount; and, performing a current changing control for increasing and reducing the input current to the torque distribution device. The step of performing a current changing control includes causing the input current to the torque distribution device to be temporarily increased to a value greater than the current value corresponding to the target torque distribution amount, and then returned to the current value corresponding to the target torque distribution amount, and repeating the temporary increasing of the input current at least at intervals of a predetermined time.