Abstract: A driving force distribution apparatus includes a basic distribution ratio calculator, a servo controller, and an adjuster. The basic distribution ratio calculator is configured to calculate a basic distribution ratio between a front driving force for front wheels and a rear driving force for rear wheels based on loads exerted on the front and rear wheels of a vehicle. The servo controller is configured to correct the basic distribution ratio so as to increase or decrease the basic distribution ratio based on a deviation between a target value of a rotation difference between the front and rear wheels and a measured value of the rotation difference between the front and rear wheels. The adjuster is configured to perform adjustment so that the rear driving force calculated based on the basic distribution ratio corrected by the servo controller does not exceed a total driving force.

Abstract: A driving force distribution control apparatus for a four-wheel drive vehicle includes a theoretical value calculator, a normative value calculator, and a servo controller. The theoretical value calculator is configured to calculate a primary rotational speed theoretical value of primary drive wheels and a secondary rotational speed theoretical value of secondary drive wheels based on a steering angle, a vehicle speed, a yaw rate, and a slip angle of the four-wheel drive vehicle and configured to calculate a rotational difference normative theoretical value indicating a difference between rotational speed theoretical values of input and output shafts of a drive force distribution apparatus using the primary rotational speed theoretical value and the secondary rotational speed theoretical value.

Abstract: A driving force distribution control apparatus for a four-wheel drive vehicle includes a basic distribution determination device and a servo controller. The basic distribution determination device is configured to determine basic distribution of a driving force to secondary drive wheels in accordance with the driving force and driving conditions of the vehicle. The basic distribution determination device includes a tire force limit determination device and an arithmetic device. The tire force limit determination device is configured to calculate a tire required acceleration in accordance with the driving conditions of the vehicle and configured to output a basic distribution adjustment signal having a characteristic that gradually decreases a ratio of the basic distribution for the secondary drive wheels to zero in a transient region in which the calculated tire required acceleration is lower than a predetermined threshold value.

Abstract: A driving force distribution apparatus includes a basic distribution ratio calculator, a servo controller, and an adjuster. The basic distribution ratio calculator is configured to calculate a basic distribution ratio between a front driving force for front wheels and a rear driving force for rear wheels based on loads exerted on the front and rear wheels of a vehicle. The servo controller is configured to correct the basic distribution ratio so as to increase or decrease the basic distribution ratio based on a deviation between a target value of a rotation difference between the front and rear wheels and a measured value of the rotation difference between the front and rear wheels. The adjuster is configured to perform adjustment so that the rear driving force calculated based on the basic distribution ratio corrected by the servo controller does not exceed a total driving force.

Abstract: A travel control apparatus for a four-wheel drive vehicle includes a throttle controller, a driving force distributor, a four-wheel drive controller, a vehicle stability assist controller, a requested target drive torque calculator, and an estimated drive torque calculator. In a case where a failure detector detects a failure and the four-wheel drive controller changes a drive control from a four-wheel drive control to a two-wheel drive control, the travel control apparatus sends a first throttle control signal to the throttle controller and changes the drive control from the four-wheel drive control to the two-wheel drive control when an estimated drive torque is greater than an requested target drive torque, and the travel control apparatus changes the drive control from the four-wheel drive control to the two-wheel drive control without sending the first throttle control signal when the estimated drive torque is not greater than the requested target drive torque.

Abstract: A driving force distribution control apparatus for a four-wheel drive vehicle includes a theoretical value calculator, a normative value calculator, and a servo controller. The theoretical value calculator is configured to calculate a primary rotational speed theoretical value of primary drive wheels and a secondary rotational speed theoretical value of secondary drive wheels based on a steering angle, a vehicle speed, a yaw rate, and a slip angle of the four-wheel drive vehicle and configured to calculate a rotational difference normative theoretical value indicating a difference between rotational speed theoretical values of input and output shafts of a drive force distribution apparatus using the primary rotational speed theoretical value and the secondary rotational speed theoretical value.

Abstract: A travel control apparatus for a four-wheel drive vehicle includes a throttle controller, a driving force distributor, a four-wheel drive controller, a vehicle stability assist controller, a requested target drive torque calculator, and an estimated drive torque calculator. In a case where a failure detector detects a failure and the four-wheel drive controller changes a drive control from a four-wheel drive control to a two-wheel drive control, the travel control apparatus sends a first throttle control signal to the throttle controller and changes the drive control from the four-wheel drive control to the two-wheel drive control when an estimated drive torque is greater than an requested target drive torque, and the travel control apparatus changes the drive control from the four-wheel drive control to the two-wheel drive control without sending the first throttle control signal when the estimated drive torque is not greater than the requested target drive torque.

Abstract: A driving force distribution control apparatus for a four-wheel drive vehicle includes a basic distribution determination device and a servo controller. The basic distribution determination device is configured to determine basic distribution of a driving force to secondary drive wheels in accordance with the driving force and driving conditions of the vehicle. The basic distribution determination device includes a tire force limit determination device and an arithmetic device. The tire force limit determination device is configured to calculate a tire required acceleration in accordance with the driving conditions of the vehicle and configured to output a basic distribution adjustment signal having a characteristic that gradually decreases a ratio of the basic distribution for the secondary drive wheels to zero in a transient region in which the calculated tire required acceleration is lower than a predetermined threshold value.

Abstract: The estimated drive torque calculation unit, is configured such that if the running condition determination unit determines that the transmission mechanism is in gear, and if the speed of rotation of the output shaft of the torque converter measured by the rotation speed measurement sensor is equal to or less than a predetermined speed of rotation, and if the rotation speed of the wheels measured by the wheel speed sensor is equal to or greater than a predetermined rotation speed, the torque combination unit calculates the first estimated drive torque as the engine estimated drive torque even if the slip ratio of the torque converter is equal to or less than a predetermined value, and even if the first estimated drive torque calculated by the first drive torque calculation unit is greater than the second estimated drive torque calculated by the second drive torque calculation unit.

Abstract: The estimated drive torque calculation unit, which is the drive torque estimation device according to the present invention, is configured such that if the running condition determination unit determines that the transmission mechanism is in gear, and if the speed of rotation of the output shaft of the torque converter measured by the rotation speed measurement sensor is equal to or less than a predetermined speed of rotation, and if the rotation speed of the wheels measured by the wheel speed sensor is equal to or greater than a predetermined rotation speed, the torque combination unit calculates the first estimated drive torque as the engine estimated drive torque even if the slip ratio of the torque converter is equal to or less than a predetermined value, and even if the first estimated drive torque calculated by the first drive torque calculation unit is greater than the second estimated drive torque calculated by the second drive torque calculation unit.

Abstract: There is disclosed a driving force control system for a four-wheel drive vehicle, which is capable of properly controlling the execution and cancellation of a lock mode in which the engagement forces of clutches for distributing a driving force to auxiliary drive wheels are made maximum, thereby reducing frequency and duration of the lock mode. Further, there is disclosed a driving force control system for a four-wheel drive vehicle, which is capable of properly controlling the engagement forces of clutches for distributing a driving force of the main drive wheels to auxiliary drive wheels, thereby causing the clutches to efficiently operate without waste of power.

Abstract: An apparatus for determining a failure of an electromagnetic clutch, which is capable of properly determining whether or not a failure, a typically a layer short-circuit, has occurred due to a change in a resistance value of a solenoid coil of the electromagnetic clutch. The electromagnetic clutch is configured such that the engagement force thereof is varied according to an amount of current flowing through the coil. An output control value for control of the amount of current is calculated by feedback control such that an actual amount of current actually flowing through the coil becomes equal to a desired amount of current. A predetermined reference control value is stored which defines a standard for the output control value and has a standard relationship with respect to the amount of current. The actual amount of current is detected. The calculated output control value is compared with the predetermined reference control value corresponding to the detected actual amount of current.

Abstract: A driving force control system for a four-wheel drive vehicle, which is capable of preventing occurrence of a tight-turn braking phenomenon by relatively simple construction to thereby reduce the manufacturing cost thereof, and at the same time, enhancing the response of slippage-eliminating control on main drive wheels, and stability of the vehicle. The 2/WD·ECU of the driving force control system controls electromagnetic clutches of a four-wheel drive vehicle having front wheels as main drive wheels and rear wheels as auxiliary drive wheels, whereby the LSD torque to be distributed to the rear wheels is controlled.

Abstract: A driving force control system for a four-wheel drive vehicle for controlling the execution and cancellation of a lock mode in which the engagement forces of clutches for distributing a driving force to auxiliary drive wheels are made maximum. The driving force control system properly controls the engagement forces of clutches for distributing a driving force of the main drive wheels to auxiliary drive wheels. When the vehicle is determined to be in a predetermined low vehicle speed condition and the transmission is in any of predetermined low-speed shift positions, execution of a lock mode is permitted in which the clutch engagement forces are controlled to lock the main and auxiliary drive wheels to each other. When the driving force of the main drive wheels is lower than a predetermined value, the clutch engagement forces for the lock mode are limited to smaller ones than the lockable ones.

Abstract: A driving force control system for a four-wheel drive vehicle. An automatic-mode transmitted torque is calculated based on operating conditions of the vehicle. When lock mode-executing conditions including operation of a lock switch by the driver are satisfied, a lock mode in which the engagement forces of the clutches are set to a lock-mode transmitted torque, including a lockable transmitted torque which can lock the front wheels and the rear wheels to each other. Further, the lock mode transmitted torque is limited depending on a traveling condition of the vehicle such that the lock-mode transmitted torque is held below the lockable transmitted torque. When the automatic-mode transmitted torque is larger than the limited lock-mode transmitted torque during the lock-mode, the engagement forces of the clutches are set to the automatic-mode transmitted torques.

Abstract: A driving force control system for a four-wheel drive vehicle[is disclosed] which enables the vehicle to smoothly start on a low-&mgr; road surface, and is capable to distributing just required amounts or driving forces to auxiliary drive wheels depending on an actual accelerating condition of the vehicle, thereby improving the response and fuel economy of the vehicle. The four-wheel drive vehicle includes front wheels as main drive wheels, and rear wheels as auxiliary drive wheels. The driving force control system controls engagement forces of electromagnetic clutches to thereby control the driving forces (torques) distributed to the rear wheels.

Abstract: An apparatus for determining a failure of wheel speed sensors, which is capable of properly determining whether or not a wheel speed detection system including the wheel speed sensors has failed, if at least a wheel speed detected by the wheel speed sensors indicates a stopped state of a corresponding wheel. An engine rotational speed is detected, and an input-output rotational speed ratio of a torque converter of an automatic transmission mounted in the vehicle is calculated. A shift range of the automatic transmission is detected. Whether or not the vehicle is traveling is determined based on the engine rotational speed and the input-output rotational speed ratio when the automatic transmission is in a traveling range. It is determined that the wheel speed detection system including the wheel speed sensors has failed, if it is determined that the vehicle is traveling, and at the same time, at least one of wheel speed sensors indicates a stopped state of a corresponding one of the wheels.

Abstract: There is disclosed a driving force control system for a four-wheel drive vehicle, which is capable of properly controlling the execution and cancellation of a lock mode in which the engagement forces of clutches for distributing a driving force to auxiliary drive wheels are made maximum, thereby reducing frequency and duration of the lock mode. Further, there is disclosed a driving force control system for a four-wheel drive vehicle, which is capable of properly controlling the engagement forces of clutches for distributing a driving force of the main drive wheels to auxiliary drive wheels, thereby causing the clutches to efficiently operate without waste of power.

Abstract: There is provided a driving force control system for a four-wheel drive vehicle, which is capable of preventing occurrence of a tight-turn braking phenomenon by relatively simple construction to thereby reduce the manufacturing cost thereof, and at the same time, enhancing the response of slippage-eliminating control on main drive wheels, and stability of the vehicle. The 2/WD·ECU of the driving force control system 1 controls electromagnetic clutches of a four-wheel drive vehicle having front wheels as main drive wheels and rear wheels as auxiliary drive wheels, whereby the LSD torque to be distributed to the rear wheels is controlled.

Abstract: There is provided a driving force control system for a four-wheel drive vehicle. An automatic-mode transmitted torque is calculated based on operating conditions of the vehicle. When lock mode-executing conditions including operation of a lock switch by the driver are satisfied, a lock mode in which the engagement forces of the clutches are set to a lock-mode transmitted torque, including a lockable transmitted torque which can lock the front wheels and the rear wheels to each other. Further, the lock-mode transmitted torque is limited depending on a traveling condition of the vehicle such that the lock-mode transmitted torque is held below the lockable transmitted torque. When the automatic-mode transmitted torque is larger than the limited lock-mode transmitted torque during the lock mode, the engagement forces of the clutches are set to the automatic-mode transmitted torques.