Abstract: A four-wheel drive vehicle has front wheels and rear wheels driven by an engine, and a coupling for changing the distribution ratio of torque to the front wheels and the rear wheels. An ECU determines whether engine braking is being applied based on the vehicle speed V and the throttle opening degree Od. When determining that engine braking is being applied, the ECU temporarily performs the engine braking related control. The ECU controls the engaging force of the coupling such that the distribution ratio of torque to the front wheels and the rear wheels is changed to a more equalized state in the engine braking related control than that before the engine braking related control is started. Accordingly, the fixing force of the front wheels and the rear wheels is temporarily increased without delay when engine braking is applied.

Abstract: A vehicle has a transmission apparatus that changes the distribution of power transmitted from a power source to a plurality of wheels. The method for distributing power of the vehicle includes detecting the temperature of a part located on a power transmission path between the power source and a wheel to which power is transmitted from the power source through the transmission apparatus, the heat of the part being increased as the power distribution ratio is increased; determining that the current state is a specific state in which the detected temperature reaches a previously set first reference temperature; and controlling the transmission apparatus to lower the power distribution ratio to the wheel from the transmission apparatus when the current state is determined to the specified state.

Abstract: A four-wheel drive vehicle includes a coupling, which varies the distribution ratio of torque to the front wheels and the rear wheels. The distribution ratio of torque to the front wheels and the rear wheels is determined by the engaging force of the coupling. An ECU sets first to third determination threshold values for the opening degree of a throttle valve of an engine in accordance with the detected vehicle speed. The ECU determines whether the vehicle is in a steady driving state by comparing the detected throttle opening degree with the set first to third determination threshold values and controls the engaging force of the coupling in accordance with the determination result. Thus, the steady driving state of the vehicle is correctly determined.

Abstract: A four-wheel drive vehicle has front wheels and rear wheels driven by an engine, and a coupling for changing the distribution ratio of torque to the front wheels and the rear wheels. An ECU determines whether engine braking is being applied based on the vehicle speed V and the throttle opening degree Od. When determining that engine braking is being applied, the ECU temporarily performs the engine braking related control. The ECU controls the engaging force of the coupling such that the distribution ratio of torque to the front wheels and the rear wheels is changed to a more equalized state in the engine braking related control than that before the engine braking related control is started. Accordingly, the fixing force of the front wheels and the rear wheels is temporarily increased without delay when engine braking is applied.

Abstract: A vehicle has a transmission apparatus that changes the distribution of power transmitted from a power source to a plurality of wheels. The method for distributing power of the vehicle includes detecting the temperature of a part located on a power transmission path between the power source and a wheel to which power is transmitted from the power source through the transmission apparatus, the heat of the part being increased as the power distribution ratio is increased; determining that the current state is a specific state in which the detected temperature reaches a previously set first reference temperature; and controlling the transmission apparatus to lower the power distribution ratio to the wheel from the transmission apparatus when the current state is determined to the specified state.

Abstract: A four-wheel drive vehicle includes a coupling, which varies the distribution ratio of torque to the front wheels and the rear wheels. The distribution ratio of torque to the front wheels and the rear wheels is determined by the engaging force of the coupling. An ECU sets first to third determination threshold values for the opening degree of a throttle valve of an engine in accordance with the detected vehicle speed. The ECU determines whether the vehicle is in a steady driving state by comparing the detected throttle opening degree with the set first to third determination threshold values and controls the engaging force of the coupling in accordance with the determination result. Thus, the steady driving state of the vehicle is correctly determined.

Abstract: An automatic transmission control system for an automatic transmission including a hydraulic pressure control circuit which supplies locking and unlocking pressures selectively to a plurality of friction coupling elements to lock and unlock the selected friction coupling elements, changing a torque transmission path in a transmission gear mechanism to provide available gears, a specific one of which is achieved by locking and unlocking simultaneously specific friction coupling elements.

Abstract: A control system for a four-wheel drive vehicle includes a center differential provided between a front shaft and a rear shaft. The control system also includes a device for restricting a differential between the front shaft and the rear shaft by operating the center differential to be in a locking condition and a controller for controlling the differential restricting device so that a differential restricting force is increased based on an increase in an engine output. The differential restricting force is decreased based on an increase in a vehicle body speed.

Abstract: A control system for a four-wheel drive vehicle includes a first differential provided between a front shaft and a rear shaft and a second differential provided between a right wheel and a left wheel. The control system comprises a first device provided in the first differential for restricting a differential between the front shaft and the rear shaft, a second device provided in the second differential for restricting a differential between the right wheel and the left wheel, and a device for controlling the restricting operations carried out by the first device and the second device. The controlling device includes a device for controlling operational timings in the first device and the second device so that the timing when the first device maintains the first differential in locking condition is different from the timing when the second device maintains the second differential in locking condition.

Abstract: A transfer case operation mode shifting apparatus is actuated by an electric actuator including an electric motor and a differential power transmitting mechanism which transmits a driving power for axially moving a differential gear shift member to shift a center-differential gear assembly between a four-wheel and a two-wheel drive mode of operation. The driving power transmitted by the differential power transmitting mechanism and acting on the differential gear shift means is smaller when shifting the center-differential gear assembly from the four-wheel to the two-wheel drive mode of operation than when shifting back the center-differential gear assembly from the two-wheel to the four-wheel drive mode of operation.

Abstract: A torque control system for vehicles provided with a four-wheel drive mechanism including a power plant having an engine and transmission, and torque control means for controlling a torque distribution between front and rear wheels detecting rotation speed difference between the front and rear wheels so that the torque distribution ratio of the rear wheels to the front wheels can be maintained at a given constant value irrespective of a change of the output torque of the power plant. The torque control system is provided with a vehicle speed sensor and steering angle sensor in order to obtain the rotation speed difference.