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 driving force of a vehicle includes estimating a first maximum road surface frictional coefficient based on a driving stiffness defined by a micro slip ratio and driving force of drive wheels, in a first driving state where the vehicle travels straight at a constant acceleration, estimating a second maximum road surface frictional coefficient based on a steering reaction force detected by an electric power steering device, in a second driving state different from the first state and where the vehicle is steered, estimating a third maximum road surface frictional coefficient to be a given value in a third driving state different from the first and second states and where an outdoor air temperature is above a determination temperature, and controlling the driving force to settle within a friction circle defined by each of the highest frictional coefficients and a ground contact load of the drive wheels.

Abstract: A wheel load estimation method of a four-wheel drive vehicle driven by a rotational driving device comprises a correlation relationship setting step for previously setting a correlation relationship between a total weight and at least one of the front wheel load and the rear wheel load by variously changing a movable load of the vehicle, a total vehicle weight computation step for calculating a current total vehicle weight from an output torque of the rotational driving device and a longitudinal acceleration of the vehicle corresponding to the output torque, and a wheel load estimation step for estimating the wheel load of at least a driving wheel from the correlation relationship and the total vehicle weight.

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 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 driving force of a vehicle includes estimating a first maximum road surface frictional coefficient based on a driving stiffness defined by a micro slip ratio and driving force of drive wheels, in a first driving state where the vehicle travels straight at a constant acceleration, estimating a second maximum road surface frictional coefficient based on a steering reaction force detected by an electric power steering device, in a second driving state different from the first state and where the vehicle is steered, estimating a third maximum road surface frictional coefficient to be a given value in a third driving state different from the first and second states and where an outdoor air temperature is above a determination temperature, and controlling the driving force to settle within a friction circle defined by each of the highest frictional coefficients and a ground contact load of the drive wheels.

Abstract: A wheel load estimation method of a four-wheel drive vehicle driven by a rotational driving device comprises a correlation relationship setting step for previously setting a correlation relationship between a total weight and at least one of the front wheel load and the rear wheel load by variously changing a movable load of the vehicle, a total vehicle weight computation step for calculating a current total vehicle weight from an output torque of the rotational driving device and a longitudinal acceleration of the vehicle corresponding to the output torque, and a wheel load estimation step for estimating the wheel load of at least a driving wheel from the correlation relationship and the total vehicle weight.

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 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 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, 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.