Abstract: A method of operating a machine having a lockable differential includes monitoring a first operating parameter indicative of wheel slip, and monitoring a second operating parameter different from the first parameter, the method further including controlling locking and unlocking of the differential responsive to the second operating parameter. A machine is provided having an electronic controller including software control logic for controlling locking and unlocking of a differential, the electronic controller being configured to lock the differential where the machine is in an operating mode where wheel slip is likely, such as a digging/dozing mode. Satisfaction of criteria for locking may be recognition by the controller of a predetermined pattern of sensor inputs corresponding with a likely wheel slip condition, or actual slip detection.

Abstract: A method for controlling the rotational speed of at least one rotating element in a vehicle's drive line is provided. A first control model and a second control model are defined. The first control model calculates a permitted slippage of at least one of the vehicle's ground-engaging elements at its point of contact with the ground, which ground-engaging element is driven via the rotating element. The second control model calculates a torque delivered to the said ground-engaging element. The result of one of the said control models is utilized for controlling the rotational speed of the rotating element.

Abstract: A driving force control device includes an individual-wheel friction-circle limit-value calculating portion that calculates friction-circle limit-values of individual wheels, an individual-wheel requested-resultant-tire-force calculating portion that calculates requested resultant tire forces of the individual wheels, an individual-wheel resultant-tire-force calculating portion that calculates resultant tire forces of the individual wheels, an individual-wheel requested-excessive-tire-force calculating portion that calculates requested excessive tire forces of the individual wheels, an individual-wheel excessive-tire-force calculating portion that calculates excessive tire forces of the individual wheels, an excessive-tire-force calculating portion that calculates an excessive tire force, an over-torque calculating portion that calculates an over-torque, and a control-amount calculating portion that calculates a control amount that is output to an engine control unit.

Abstract: A rotation speed of a transmitting member is controlled such that a predetermined rotation speed difference or predetermined rotation speed ratio is obtained between the rotation speed of the transmitting member and an eighth rotating element or a fourth rotating element. By detecting a change in the rotation speed of a second motor that is connected to the transmitting member when an apply device is applied, it is possible to determine the time at which a first clutch or a second clutch starts to be applied and the time at which the first clutch or the second clutch is completely applied. As a result, it is possible to control the apply pressure of the first clutch or the second clutch and thus rapidly execute a shift.

Abstract: This invention provides a vehicle motion control method and a vehicle motion control apparatus capable of improving the behavior stability of a vehicle. According to the vehicle motion control method, vehicle steering characteristic is determined based on a behavior amount differentiated value obtained by differentiating (S203) a slip angle differential value which is a behavior amount of the vehicle which occurs around a z-axis in the vertical direction with respect to the vehicle body (S205, S209). Consequently, because the phase of the slip angle differential value is progressed, the transition tendency of the steering characteristic, that is, which the vehicle motion condition is moved to over-steer or under-steer, can be obtained early. Therefore, the starting timing of the steering control or drive power control of the vehicle can be accelerated thereby improving the behavior stability of the vehicle.

Abstract: Method and device for providing, in an engine-driven goods vehicle, at least two driving wheels (9, 10, 51, 52) and at least one differential (5, 6, 45, 46, 47) arranged between the driving wheels (9, 10, 51, 52). The device includes an engine control unit (3), at least one differential lock (7, 8, 48, 49, 50) for locking or braking the differential (5, 6, 45, 46, 47), the differential lock (7, 8, 48, 49, 50) being arranged between the driving wheels (9, 10, 51, 52). An operating element (4, 44) for activating each of the differential locks (7, 8, 48, 49, 50). The engine control unit (3) being configured to read-off the position of the operating element (4, 44) and to limit positive or negative output torques of the engine (1) when activating at least one of the differential locks (7, 8, 48, 49, 50) and as a function of the transmission ratio prevailing in the transmission (2, 42).

Abstract: A vehicle stability control system includes a controller configured to deactivate a traction control clutch, provide a reverse torque across the traction control clutch, and apply a braking torque according to a vehicle stability control strategy. The reverse torque across the traction control clutch may be provided by reducing an engine torque output, applying a pulse of brake pressure, or other means.

Abstract: A plurality of vehicle stabilizing devices which operate according to different strategies and which actuate, independently of the driver, brake actuators which are assigned to the vehicle wheels, in order to stabilize the vehicle are arranged in the vehicle. The vehicle is equipped with at least one switchable differential lock in the drive train. The differential lock assumes a non-switched operating state, a first operating state in which the differential lock is preselected, and a second operating state in which the differential lock is switched. When the differential lock assumes the first operating state, some of the vehicle stabilizing devices, other than that vehicle stabilizing device which, by actuating the brake actuators independently of the driver, prevents the vehicle wheels from locking during a braking operation, are influenced in terms of their operating mode.

Abstract: A control for a differential including magnetic powder torque transfer clutch for controlling slip across the differential mechanism. The clutch includes a first element driveably connected to a first control shaft, a second element driveably connected to the second output shaft, chamber bounded by the first and second elements, magnetic powder located in the chamber; and an elecromagnetic coil producing a magnetic field of variable strength passing through the chamber and magnetic powder and changing a capacity of the clutch to transmit torque between the first and second control shafts as the field strength changes.

Abstract: A system controls torques applied to a plurality of wheels of a motor vehicle. One or more angular velocity sensors determine speed for each of the plurality of wheels. A vehicle yaw acceleration sensor determines actual yaw acceleration of the vehicle. A desired yaw acceleration sensor determines intended yaw acceleration for the vehicle. A net torque command sensor determines intended vehicle direction and intended torque magnitude for the vehicle. An electronic control unit processes data from the velocity sensors, the vehicle yaw acceleration sensor, the desired yaw acceleration sensor and the net torque command sensor to generate torque signals for the plurality of wheels. One or more torque producers responds to the torque signals to vary torque applied to each of the plurality of wheels, such that the wheels engage in one of acceleration and deceleration dependent upon driver intent and with controlled traction.

Abstract: A drive-force distribution controller controls a drive-force transmission apparatus of a vehicle in order to control transmission of drive force to rear wheels or front wheels of the vehicle in accordance with a designated drive-force transmission ratio. The drive-force transmission ratio is changed on the basis of vehicle speed, differential rotational speed (speed difference between the front and rear wheels), and throttle opening. Alternatively, the drive-force transmission ratio is changed on the basis of vehicle speed, throttle opening, and throttle open speed. The change speed of current which is supplied to the drive-force transmission apparatus in order to control the drive-force transmission ratio is adjusted in accordance with a command current filter value which is determined on the basis of vehicle speed and a command current filter map of a vehicle-speed responsive type.

Abstract: In a vehicle in which an engine output power is transmitted to front and rear wheels through a transmission and an inter axle differential, a wheel lock prevention device is provided. The wheel lock prevention device comprises a differential lock mechanism for locking the inter axle differential, a detection element for detecting a wheel lock state of the front and rear wheels, and an operation element for operating the differential lock mechanism so as to lock the inter axle differential by operating the differential lock mechanism upon the detection of the wheel lock state.

Abstract: The invention concerns a method for reducing wheel slippage of a motor vehicle with at least one axle (2), on the ends of which steerable wheels (7, 8) are rotatingly placed, and with at least one axle (1, 2) on which wheels (5, 6, 7, 8) are driven by a differential drive (3, 4), whereby, in case of a wheel slip of one of the wheels of a driven axle (1, 2), a brake (16, 17) assigned thereto or a differential slip control is activated and controlled.

Abstract: A drive-force distribution controller for a four-wheel-drive vehicle in which drive force produced by an engine is transmitted directly to front or rear wheels and is transmitted to the remaining wheels via a torque distribution clutch, and the engagement force of the torque distribution clutch is controlled in accordance with traveling conditions of the vehicle. The controller includes a calculation unit for calculating variation per unit time in rotational speed difference between the front wheels and the rear wheels; and a control unit for controlling the engagement force such that the engagement force increases as the variation per unit time in the rotational speed difference increases.

Abstract: A method and a system for limiting an engine torque of vehicles to a maximum value. In the method, signals representing wheel torques from wheel sensors at the drive train are acquired, the wheel torques, differentiated according to driving situations which can have a harmful influence on the transmission, differential or torque converter, then being checked for a wheel-torque value which is too high. If too high a value is found, the engine torque is limited or reduced.

Abstract: A transfer case control system or apparatus 10 is provided for use on a four-wheel drive vehicle of the type having a transfer case 32, a front driveshaft 22 and a rear driveshaft 26. Transfer case control system 10 includes a conventional microcontroller or controller 40 having a memory unit 42 and operating under stored program control. Controller 40 is communicatively coupled to sensors 44, 46, 48, and to a transfer case 32. Controller 40 selectively generates a control signal having a proportional term or component and an integral term or component. The control signal is generated to transfer case 32 and controls the amount of torque provided to driveshafts 22, 26.

Abstract: The present invention provides a vehicle dynamic control system which alters characteristics of respective vehicle movement controllers so that they can function properly against coming and foreseeable running conditions and current running conditions, recognizing beforehand details of an emerging curve on the road to be traveled. The system comprises a vehicle movement control alterant and at least one among vehicle movement controllers, i.e., a brake controller, a left/right wheel differential limiter controller and power distribution controller. When the vehicle is approaching the curve, the vehicle movement control alterant alters characteristics of a braking controller, the left/right wheel differential limiter controller and the power distribution controller to those favorable to turning for driving through a curve appropriately.

Abstract: When an accelerator pedal is released, or when a brake pedal is depressed and if braking force is lower than a reference braking force corresponding to a braking force immediately before causing a wheel lock, differential limiting force of a center differential is set to a predetermined value so as to retain an under-steer condition while engine brake is applied. When the brake pedal is depressed and if braking force is higher than the reference braking force, differential limiting force of the center differential is set to zero so as to assist an anti-lock brake system. Further, the reference braking force can be determined according to a road friction coefficient, a grade of road, a lateral acceleration and the like. Further, the predetermined value of the differential limiting force may be a constant value or may be a value corresponding to a front-to-rear weight distribution ratio.

Abstract: An all wheel drive mechanism has a powertrain including an engine, transmission, front drive differential, a rear drive transfer gearing and a selectively operable rear drive mechanism. The rear drive mechanism has a housing, driven by the transfer gearing through a drive shaft. A pair of selectively engageable clutches, which are operable to connect the rear wheels to the housing, are disposed in the housing. A pair of pumps are assembled in the housing to provide operating fluid for the clutches. Each pump has one member secured for rotation with the housing and another member secured for rotation with respective rear wheel drive axles. An inlet of the pumps is controlled by a solenoid operated valve which is energized in response to an anti-lock brake system and traction control system of the vehicle. When energized, the valve connects the pumps to a reservoir such that fluid in the reservoir can be pumped to the clutches to enforce engagement thereof resulting in a drive path to the rear wheels.

Abstract: The invention proceeds from a control of the drive train of a motor vehicle having at least a drive unit and an automatic transmission. During driving operation, a desired value for the drive torque of the vehicle or for the transmission output torque is pregiven by the driver. The different operating points of the drive train are characterized by at least different output torques of the drive unit and rpm ratios and/or different output rpms of the drive unit. The essence of the invention is that, during driving operation, a set of evaluation quantities is determined for each possible operating point. One of the possible operating points is then selected as an optimal operating point via an optimization method based on the determined evaluation quantities. The transmission ratio, which belongs to this selected optimal operating point, is then adjusted on the transmission.

Abstract: In a motor vehicle with one or several driven axles, as well as with corresponding equalizing gears and/or power dividers for the compensation of differences in the speeds of the wheels, the spinning of wheels and/or axles is avoided through the use of braking devices for the braking of individual wheels, in conjunction with locking devices for the above-mentioned equalizing gears and/or power dividers. Upon reaching a predetermined speed difference value between the drive axles, a reduction of this speed difference is first brought about by actuation of the corresponding braking devices. When a predetermined approach tendency of the wheel speeds to each other is reached, a synchronization of the wheels is obtained by actuating the appropriate locking device. In this manner, a synchronization of rotating parts is achieved during any speed behavior of the rotating parts, without damage to parts of the motor vehicle.

Abstract: A differential lock control system for controlling the locking of the various differential assemblies associated with a particular work machine wherein such system includes a first switch positionable to select any one or more of the differential assemblies for operation in their locked condition, a second switch actuatable to control the locking of the differential assemblies selected by the first switch, a ground speed sensor for determining the ground speed of the work machine, an optional steering pressure sensor for determining the steering effort required to turn the wheels associated with the front axle, and an electronic controller coupled to the first and second switches and to the respective sensors for receiving signals therefrom, the controller outputting a signal to actuate the locking mechanism of the differential assemblies selected by the position of the first switch when the controller receives a signal indicative of the second switch being actuated, and a signal indicative of the ground spee

Abstract: For automatically controlling a differential lock in drive axles of a motor vehicle, an arrangement has a lock coupling, an actuator for actuating the lock coupling, a plurality of rotary speed sensors associated with wheels of the vehicle for forming the rotary speed signal, a control unit for receiving the rotary speed signals and forming a control signal for controlling the actuator means, the control unit including computing means for computing a nominal rotary speed value associated with each of the wheels so that a computed nominal rotary speed value is determined continuously in dependence from a corresponding traveling condition, a first comparing unit for forming a difference rotary speed value from a comparison of a measured rotary speed value with the computed nominal rotary speed value, and a second comparing unit for forming the control signal so that when the difference rotary speed value exceeds a predetermined threshold value the lock coupling is engaged and when the difference rotary speed va

Abstract: A method for the automatic locking of the differentials of an all-wheel driven vehicle, slip signals being formed which, as soon as they exceed a threshold value, initiate the driving of the respective differentials. In order to take into account the influence of the steering rolling radius, the change in the steering value is ascertained. From this, using a function determined by the geometry of the vehicle, an apparent slip is ascertained. From the respective apparent slip, corrected threshold values are determined and measured slip signals are compared with the corrected threshold values and, if necessary, the driving of the respective differential is initiated. The method can also be used on a vehicle having articulated-vehicle steering.

Abstract: A system for correcting drive wheel slippage in a heavy vehicle includes a front non-drive axle and either a single or tandem rear drive axle with an inter-axle differential with locking capability. Each drive axle also includes a main differential with locking capability. The system further includes a first sensor for measuring the rotational speed of the driveshaft and a second sensor for measuring non-driven wheel speed. A central processor compares the driveshaft speed to the non-driven wheel speed and locks the inter-axle differential of a tandem rear drive axle to drive the front and rear drive axles at the same speed or locks the main differential of a single rear drive axle to drive the first and second driven wheels at the same speed when the ratio of the driveshaft speed signal to the first non-driven wheel speed signal exceeds the predetermined limit. In the tandem configuration, if drive wheel slippage continues, the main differentials of the front and rear drive axles are also locked.

Abstract: A unit for smoothly switching from auto-drive to manual drive for a vehicle provided with an auto-drive mode. To perform auto-drive, an auto-drive ECU controls steering wheel, brake, and accelerator actuators in accordance with signals from a route recognition/obstruction check sensor, a GPS and the like. When an interface (switch) for switching to the manual drive is operated, the auto-drive ECU evaluates running stability/instability in accordance with signals from various running safety devices and sensors for detecting a variation in vehicle state, and if the vehicle is in an instable state, prohibits a shift to the manual drive, even when the vehicle is running on a straight road.

Abstract: A motor vehicle control system including a differential for connecting vehicle wheels so as to permit differential actions of the wheels, a differential control device for controlling the differential, and a wheel rotation control device for controlling the rotation of the wheels, wherein the differential control device has an operator-controlled member whose output indicates a vehicle operator's desire, a vehicle condition detector for detecting the vehicle condition, a differential actuator for operating the differential so as to control the differential actions of the wheels, and a differential controller for controlling the actuator based on the outputs of the operator-controlled member and the vehicle condition detector, the system having a differential state detector whose output indicates the operating state of the differential, and a wheel rotation control determining device operated on the basis of the outputs of the operator-controlled member, differential state detector and vehicle condition detedt

Abstract: A system for controlling a four-wheel drive for a motor vehicle comprises a drive mode switch for detecting a drive mode of the motor vehicle selectable between a two-wheel drive mode and a four-wheel drive mode. The four-wheel drive mode is selectable between a direct-coupled four-wheel drive mode. A an auto four-wheel drive mode, a controller controls the distribution of traction between main and secondary driving wheels. A traction transmission train distributes traction between the main and secondary driving wheels. The traction transmission train has an oil pressure supply system having a friction clutch and a solenoid.

Abstract: A control system for engaging, disengaging and re-engaging a front wheel drive in an agricultural vehicle includes a control circuit configured to receive signals representative of vehicle operating parameters and to generate control signals corresponding to the desired state (i.e. engaged or disengaged) of a front wheel drive engagement circuit. Sensors are associated with the rear wheels, rear service brakes, implement positioning circuit, the vehicle body and the front axle to provide parameter signals related to wheel speed, braking, implement position and vehicle speed. Control logic executed by the control circuit in a continuously cycled routine determines the desired state of the engagement circuit based upon all operating parameters. The control circuit applies an appropriate control signal to the engagement circuit causing engagement or disengagement in accordance with the desired state.

Abstract: In a control system for distributing a driving force from an engine between the front and rear wheels of a vehicle, a controller is designed to decrease the driving force transmitted to the secondary drive wheels which may be the front wheels by modifying a driving force distribution control characteristic when the vehicle is in a predetermined constant speed steady state, in order to improve the fuel economy in the steady state operation while maintaining a vivid vehicle response to a driver's accelerator input. Preferably, the controller determines an offset quantity L which has at least a cubic term proportional to the third power of a vehicle speed when the predetermined steady state exists, and increases the driving force to the secondary wheels as an excess of the wheel speed difference over the offset quantity increases from zero.

Abstract: In a torque distribution control system of a four wheel drive vehicle, it is important to distribute a driving force properly between front and rear wheels according to friction coefficient of road surface. Especially when a vehicle runs on roads with low friction coefficients of road surface, it is very important to estimate friction coefficients of the road surface which vary every moment and to control the driving force according to the estimated friction coefficients. The present invention provides the torque distribution control system with means for estimating friction coefficients of road surface every moment based on data from a steering angle sensor, a vehicle speed sensor and a yaw rate sensor and for reflecting them on the calculation of torque distribution between front and rear wheels. Furthermore, yaw moment calculating means are provided to prevent the vehicle from tack-in phenomenon by properly controlling left and right wheels.

Abstract: A traction control system for a fourwheel drive vehicle having a center differential comprises a brake pressure control apparatus, an engine output control apparatus, a differential limiting torque control apparatus, vehicle speed calculating means for calculating a reference vehicle speed of a vehicle, slip amount calculating means for calculating a slip amount of each wheel, target slip amount determining means for determining a front target slip amount of front wheels and a rear target slip amount of rear wheels, traction control determining means for determining to operate a traction control when the slip amount of the front wheels exceeds the front target slip amount or when the slip amount of the rear wheels exceeds the rear target slip amount, brake pressure calculating means for calculating a brake pressure so as to apply a brake to the wheels and engine output calculating means for calculating a target engine torque corresponding to a difference between the slip amount and the target slip amount, whe