Abstract: A driving force control device 1 for a vehicle V comprises: a D-? map M1 defining a linear correlation between a driving stiffness D and a maximum road surface ?; a slip ratio calculation circuit 21 for calculating a slip ratio S of one of a pair of front road wheels 10L, 10R; a DS calculation circuit 22 for calculating the driving stiffness D corresponding to a value the slip ratio S calculated by the slip ratio calculation circuit 21; a maximum road surface ? calculation circuit 23 for assigning a value of the driving stiffness D calculated by the DS calculation circuit 22 to the D-? map M1 to calculate the maximum road surface ?; and a driving force distribution circuit 24 for controlling a driving force, using a value of the maximum road surface ? calculated by the maximum road surface ? calculation circuit 23.

Abstract: A method of controlling a driving force of a four-wheel drive vehicle includes causing a control unit to acquire a vehicle speed, a lateral acceleration, a driving force of a wheel, a road surface friction coefficient, and a ground contact load of the wheel when the vehicle is traveling, determine whether a road surface is rough based on the acquired road surface condition, correct, when the road surface is determined to be rough, the load of the wheel, by applying thereto a load change rate set according to the roughness, predict a slip occurrence of the wheel by comparing a product of the corrected load and the road surface friction coefficient to a total force of the driving force and a lateral force caused by a lateral acceleration in cornering, and reduce, when the slip occurrence is predicted, the driving force so as to prevent the slip occurrence.

Abstract: A control system of a four-wheel drive vehicle and a gradient value setting device of the vehicle is provided so as to reliably control a wheel skid despite the vehicle facing an intersecting direction intersecting a maximum tilt line direction. The vehicle includes an engine, front and rear wheels, an electronic control 4WD coupling, and a control unit. The distribution amount of the driving force to the rear wheels is set by the electronic control 4WD coupling. The control unit determines whether or not the vehicle faces the intersecting direction on the inclined road, and if so, sets the driving force distribution amount so that the difference between the driving force distribution amount to the front wheels and to the rear wheels is smaller as compared with on a flat road, and commands the electronic control 4WD coupling to distribute the driving force by the distribution amount.

Abstract: A driving force control device 1 for a vehicle V comprises: a D-? map M1 defining a linear correlation between a driving stiffness D and a maximum road surface ?; a slip ratio calculation circuit 21 for calculating a slip ratio S of one of a pair of front road wheels 10L, 10R; a DS calculation circuit 22 for calculating the driving stiffness D corresponding to a value the slip ratio S calculated by the slip ratio calculation circuit 21; a maximum road surface ? calculation circuit 23 for assigning a value of the driving stiffness D calculated by the DS calculation circuit 22 to the D-? map M1 to calculate the maximum road surface ?; and a driving force distribution circuit 24 for controlling a driving force, using a value of the maximum road surface ? calculated by the maximum road surface ? calculation circuit 23.

Abstract: A method of controlling a driving force of a four-wheel drive vehicle includes causing a control unit to acquire a vehicle speed, a lateral acceleration, a driving force of a wheel, a road surface friction coefficient, and a ground contact load of the wheel when the vehicle is traveling, determine whether a road surface is rough based on the acquired road surface condition, correct, when the road surface is determined to be rough, the load of the wheel, by applying thereto a load change rate set according to the roughness, predict a slip occurrence of the wheel by comparing a product of the corrected load and the road surface friction coefficient to a total force of the driving force and a lateral force caused by a lateral acceleration in cornering, and reduce, when the slip occurrence is predicted, the driving force so as to prevent the slip occurrence.

Abstract: A control system of a four-wheel drive vehicle and a gradient value setting device of the vehicle is provided so as to reliably control a wheel skid despite the vehicle facing an intersecting direction intersecting a maximum tilt line direction. The vehicle includes an engine, front and rear wheels, an electronic control 4WD coupling, and a control unit. The distribution amount of the driving force to the rear wheels is set by the electronic control 4WD coupling. The control unit determines whether or not the vehicle faces the intersecting direction on the inclined road, and if so, sets the driving force distribution amount so that the difference between the driving force distribution amount to the front wheels and to the rear wheels is smaller as compared with on a flat road, and commands the electronic control 4WD coupling to distribute the driving force by the distribution amount.

Abstract: A driving force distribution control apparatus includes: a driving force transmission device including a clutch which can change distribution of a driving force to front wheels and rear wheels of a four-wheel drive vehicle; and a controller which controls an engagement force of the clutch in accordance with a traveling state. The controller includes a different-diameter tire detector which detects an attachment of a different-diameter tire to one of the front wheels and the rear wheels when a rotation speed ratio between the front wheels and the rear wheels continues to be equal to or larger than a reference rotation speed ratio for a predetermined time. The different-diameter tire detector performs detection of the attachment of the different-diameter tire when it is determined that the wheels are unlikely to slip based on an outside condition.

Abstract: A driving force distribution control apparatus includes: a driving force transmission device including a clutch which can change distribution of a driving force to front wheels and rear wheels of a four-wheel drive vehicle; and a controller which controls an engagement force of the clutch in accordance with a traveling state. The controller includes a different-diameter tire detector which detects an attachment of a different-diameter tire to one of the front wheels and the rear wheels when a rotation speed ratio between the front wheels and the rear wheels continues to be equal to or larger than a reference rotation speed ratio for a predetermined time. The different-diameter tire detector performs detection of the attachment of the different-diameter tire when it is determined that the wheels are unlikely to slip based on an outside condition.

Abstract: A driving force distribution control device, which is mounted on a vehicle including an engine configured to generate driving force for the vehicle, a transmission device configured to shift rotation of an output shaft of the engine by transmission ratios, and a driving force transmission system capable of transmitting output of the transmission device to main drive wheels and auxiliary drive wheels, includes: a control device configured to, when a rotational speed of the output shaft of the engine is in a range in which abnormal sound of the driving force transmission system due to pulsation of the driving force can be generated, set a torque value to a value capable of reducing the abnormal sound depending on the driving force; and a driving force transmitting device configured to transmit driving force depending on the set value to the auxiliary drive wheels.

Abstract: A road surface frictional coefficient estimation device includes: a first straight travel determination unit configured to determine whether or not a vehicle travels straight based on a rotational speed difference between a plurality of wheels of the vehicle; a second straight travel determination unit configured to determine whether or not the vehicle travels straight based on a steering angle of the vehicle; a selection unit configured to select one of determination results of the first straight travel determination unit and the second straight travel determination unit; and a frictional coefficient estimation unit configured to estimate a frictional coefficient of a road surface on which the vehicle travels when the one of the determination results selected by the selection unit indicates that the vehicle travels straight.

Abstract: A driving force distribution control device mounted on a vehicle including an engine, a transmission device, a clutch engaging an output shaft of the engine with an input shaft of the transmission device, and a driving force transmission system capable of transmitting output of the transmission device to main and auxiliary drive wheels, includes: a control device obtaining a torque value to be transmitted to the auxiliary drive wheels, the control device reducing the torque value for a predetermined time when the vehicle is in a stopped state or in a state where a vehicle speed of the vehicle is lower than a predetermined value, and an increasing speed of engaging force of the clutch is equal to or greater than a predetermined value; and a driving force transmitting device transmitting torque depending on the obtained torque value to the auxiliary drive wheels.

Abstract: A driving force distribution control device mounted on a vehicle including an engine, a transmission device, a clutch engaging an output shaft of the engine with an input shaft of the transmission device, and a driving force transmission system capable of transmitting output of the transmission device to main and auxiliary drive wheels, includes: a control device obtaining a torque value to be transmitted to the auxiliary drive wheels, the control device reducing the torque value for a predetermined time when the vehicle is in a stopped state or in a state where a vehicle speed of the vehicle is lower than a predetermined value, and an increasing speed of engaging force of the clutch is equal to or greater than a predetermined value; and a driving force transmitting device transmitting torque depending on the obtained torque value to the auxiliary drive wheels.

Abstract: A driving force distribution control device, which is mounted on a vehicle including an engine configured to generate driving force for the vehicle, a transmission device configured to shift rotation of an output shaft of the engine by transmission ratios, and a driving force transmission system capable of transmitting output of the transmission device to main drive wheels and auxiliary drive wheels, includes: a control device configured to, when a rotational speed of the output shaft of the engine is in a range in which abnormal sound of the driving force transmission system due to pulsation of the driving force can be generated, set a torque value to a value capable of reducing the abnormal sound depending on the driving force; and a driving force transmitting device configured to transmit driving force depending on the set value to the auxiliary drive wheels.

Abstract: A road surface frictional coefficient estimation device includes: a first straight travel determination unit configured to determine whether or not a vehicle travels straight based on a rotational speed difference between a plurality of wheels of the vehicle; a second straight travel determination unit configured to determine whether or not the vehicle travels straight based on a steering angle of the vehicle; a selection unit configured to select one of determination results of the first straight travel determination unit and the second straight travel determination unit; and a frictional coefficient estimation unit configured to estimate a frictional coefficient of a road surface on which the vehicle travels when the one of the determination results selected by the selection unit indicates that the vehicle travels straight.