A vehicle including a coupling device that includes (a) an engagement clutch mechanism for coupling an input side engagement member that is coupled to a drive power source of the vehicle and an output side engagement member that is coupled to a drive wheel of the vehicle; and (b) a cam mechanism for assisting engagement of the input and output side engagement members depending on a differential torque by which the input and output side engagement members are rotated differentially. The vehicle includes a control device configured, when the engagement of the input and output side engagement members is to be released, to cause a braking force to be applied to one of the input and output side engagement members such that the differential torque is reduced.

An all-terrain vehicle is disclosed having a braking system with an anti-lock braking control module and a first brake master cylinder hydraulically coupled to the anti-lock braking control module. A first brake actuator is coupled to the first brake master cylinder and a brake caliper is coupled to at least some of the ground engaging members. The first brake master cylinder upon actuation provides anti-lock braking to either the first or second ground engaging members. A second brake master cylinder is hydraulically coupled to the anti-lock braking control module. A second brake actuator is coupled to the second brake master cylinder and a brake caliper is coupled to at least some of the ground engaging members. The second brake master cylinder upon actuation provides anti-lock braking to either the first or second ground engaging members. The vehicle also has a speed monitor with a gear ring positioned on an exterior surface of a stub shaft and a speed pickup positioned adjacent to the gear ring.

A vehicle includes front suspension assemblies; rear suspension assemblies; a left driven wheel and a right driven wheel with first left and right brake assemblies; a left wheel and a right wheel with second left and right brake assemblies; an anti-lock braking system (ABS) module; a drive mode coupler connected between the transmission and the left and right wheels for changing between a 24 and a 44 drive configuration; and a drive mode switch for controlling the drive mode coupler, the ABS module selectively performing brake traction control of at least one wheel based on the position of the drive mode switch. A method for controlling traction of the vehicle includes sensing the drive mode switch position and when the drive mode changes from a 24 position to a 44 position, causing the ABS module to perform brake traction control on at least one wheel.

A method for operating a driver assistance device for a motor vehicle. A drive potential is respectively determined from all driven wheels of at least one axis of the motor vehicle. The drive potentials are compared and a braking device with a specific wheel braking force is controlled for braking the wheel having a lower drive potential.

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.

A vehicle including a coupling device that includes (a) an engagement clutch mechanism for coupling an input side engagement member that is coupled to a drive power source of the vehicle and an output side engagement member that is coupled to a drive wheel of the vehicle; and (b) a cam mechanism for assisting engagement of the input and output side engagement members depending on a differential torque by which the input and output side engagement members are rotated differentially. The vehicle includes a control device configured, when the engagement of the input and output side engagement members is to be released, to cause a braking force to be applied to one of the input and output side engagement members such that the differential torque is reduced.

A vehicle has a frame, a straddle seat, front right and left wheels, a rear wheel, a steering assembly, a motor, front right and left brakes, a rear brake, and an electronic brake control unit. The electronic brake control unit has a pump, a valve box, a first pressure sensor disposed in the valve box and an electronic controller. The electronic controller is electronically connected to the pump, and valves of the valve box for controlling their operation. A hand brake lever actuates a first master cylinder and thereby actuates the front brakes through the valve box. A foot brake lever actuates a second master cylinder and thereby actuates the rear brake through the valve box. A second pressure sensor is disposed externally of the valve box. The first and second pressure sensors sensing fluid pressure applied by the first and second master cylinders respectively.

A vehicle driveline including a first axle assembly having a first drive ratio. A second axle assembly in selective driving engagement with the first axle assembly, the first and second axle assemblies having a second drive ratio when in driving engagement. A control system in electrical communication with the first and second axle assemblies, wherein the control system selectively engages the second axle assembly with the first axle assembly.

An all-terrain vehicle is disclosed having a braking system with an anti-lock braking control module and a first brake master cylinder hydraulically coupled to the anti-lock braking control module. A first brake actuator is coupled to the first brake master cylinder and a brake caliper is coupled to at least some of the ground engaging members. The first brake master cylinder upon actuation provides anti-lock braking to either the first or second ground engaging members. A second brake master cylinder is hydraulically coupled to the anti-lock braking control module. A second brake actuator is coupled to the second brake master cylinder and a brake caliper is coupled to at least some of the ground engaging members. The second brake master cylinder upon actuation provides anti-lock braking to either the first or second ground engaging members. The vehicle also has a speed monitor with a gear ring positioned on an exterior surface of a stub shaft and a speed pickup positioned adjacent to the gear ring.

The control device for a four-wheel drive vehicle includes a differential restriction control unit configured to cause the differential restriction device, which is enable a differential restriction degree between a front wheel rotary shaft and a rear wheel rotary shaft, to change the differential restriction degree and a braking control unit configured to cause the braking device to perform EBD control and ABS control. The braking control unit is configured to cause the braking device to suspend the EBD control when the ABS control is started while the EBD control is being performed, and the differential restriction control unit is configured to change the differential restriction degree to a third degree larger than a first degree and equal to or smaller than a second degree when the ABS control is started while the EBD control is being performed.