A clutch control method is provided for a four-wheel-drive vehicle in which the main drive wheels are connected to a drive source, and the auxiliary drive wheels are connected via a friction clutch to the drive source. When the vehicle starts off due to an accelerator depressing operation, the friction clutch is engaged to distribute, a drive torque from the drive source to the main drive wheels and the auxiliary drive wheels. In this clutch control method, when the vehicle switches from a traveling state to a stopped state while maintaining in a travel shift position, a control is preformed to apply initial torque as an engagement torque control of the friction clutch while the vehicle is stopped. A magnitude of the initial torque is set to a magnitude that maintains a drive-system torsion state by transmitting torque to an auxiliary-drive-wheel drive system before the vehicle is stopped.

A method for operating a drive train of a transportation vehicle wherein the drive train is switched between a first operating state, in which a two-wheel drive of the drive train is activated, and a second operating state, in which a four-wheel drive of the drive train is activated. The drive train is switched by an electronic computing device from one of the operating states to the other operating state. During the driving of the transportation vehicle, a demand time is determined by the electronic computing device not later than which the switching from the one operating state to the other operating state must be completed, the demand time lying in the future with respect to the determination of the demand time. The switching from the one operating state to the other operating state is commenced at a starting time in advance of the demand time.

In a four-wheel-drive vehicle having auxiliary drive wheels to which power of a drive power source is transmitted via a transmission member, in which connecting/disconnecting devices are provided between the drive power source and the transmission member and between the transmission member and the auxiliary drive wheels such that one of the connecting/disconnecting devices is a friction engagement clutch while the other is a dog clutch, when switching from two-wheel-drive running mode in which both the clutches are disconnected to four-wheel-drive running mode, an acceleration/deceleration adaptive synchronization portion sets an allowable deceleration based on a vehicle acceleration/deceleration and controls an engagement torque of the friction engagement clutch to make the deceleration of the vehicle equal to the allowable deceleration when the rotation speed of the transmission member is increased.

A hybrid vehicle includes a controller. First control is control of an engine and a motor such that the hybrid vehicle travels by switching between a charge depleting mode and a charge sustaining mode. Second control is control of the engine and the motor such that the hybrid vehicle travels in accordance with a travel plan in which the charge depleting mode or the charge sustaining mode is assigned to each travel section of a travel plan route to a destination. The controller controls the engine and the motor such that a state of charge of an electric power storage device becomes higher in the charge sustaining mode in the second control than in the charge sustaining mode in the first control.

A transfer for a four-wheel drive vehicle, the four-wheel drive vehicle configured to disconnect a propeller shaft from a power transmission path between an auxiliary drive wheels and a driving power source when the four-wheel drive vehicle travels by two-wheel drive, includes a second output rotating member and an oil pump. The second output rotating member is configured to output a driving power to the propeller shaft. The oil pump is configured to rotationally drive in conjunction with rotation of the second output rotating member via a first one-way clutch. The first one-way clutch is configured such that the oil pump supplies a lubrication oil to a wet clutch when the four-wheel drive vehicle travels forward by the four-wheel drive. The oil pump is configured to stop supplying the lubrication oil to the wet clutch when the four-wheel drive vehicle travels forward by the two-wheel drive.

An electronic controller (10) for a motor vehicle (100), the controller being configured to determine when at least one wheel (111, 112, 114, 115) has lost traction, wherein when the controller (10) determines that at least one wheel (111, 112, 114, 115) has lost traction the controller (10) is configured to provide an output to a driver indicative of the at least one wheel (111, 112, 114, 115) that has lost traction.

A four-wheel drive vehicle comprises: a dog clutch; an electronically controlled coupling; and a control device switching a drive state to the four-wheel drive state when the control device determines that a running road surface is a low friction road and switching the drive state to the two-wheel drive state when the control device determines that the running road surface is a high friction road. In the case of switching the drive state from the four-wheel drive state to the two-wheel drive state, the control device temporarily releases the electronically controlled coupling to redetermine whether the running road surface is the low friction road or the high friction road before releasing the dog clutch and prohibits switching from the four-wheel drive state to the two-wheel drive state when it is redetermined that the running road surface is the low friction road.

A vehicle includes a first axle temporary driven by a motor, a second axle permanently connected to the motor via a propeller shaft, and a sub-shaft that connects the propeller shaft and the first axle. A control system for a connection between the motor and the first axle includes a first clutch between the propeller shaft and the sub-shaft, a second clutch between the sub-shaft and the first axle. The first clutch is controlled to continue applying a synchronous torque until the second clutch is determined to be connected. The second clutch is controlled to be connected in response to a determination that the second clutch is connectable.

A clutch control method is provided for a four-wheel-drive vehicle in which the main drive wheels are connected to a drive source, and the auxiliary drive wheels are connected via a friction clutch to the drive source. When the vehicle starts off due to an accelerator depressing operation, the friction clutch is engaged to distribute, a drive torque from the drive source to the main drive wheels and the auxiliary drive wheels. In this clutch control method, when the vehicle switches from a traveling state to a stopped state while maintaining in a travel shift position, a control is preformed to apply initial torque as an engagement torque control of the friction clutch while the vehicle is stopped. A magnitude of the initial torque is set to a magnitude that maintains a drive-system torsion state by transmitting torque to an auxiliary-drive-wheel drive system before the vehicle is stopped.

A vehicle body speed estimation device and a vehicle body speed estimation method are provided for estimating a vehicle body speed of a four-wheel drive vehicle from a wheel speed of each wheel of the four-wheel drive vehicle. In the vehicle body speed estimation device and a vehicle body speed estimation method, a controller determines whether a deviation of at least two of the wheel speeds among the wheel speeds is within a first prescribed range. The controller switches a method for selecting the wheel speed used for estimating the vehicle body speed between a first method and a second method when a sign of a drive torque that is applied to each of the wheels is reversed and the deviation of at least two of the wheel speeds among the wheel speeds is within the first prescribed range.