Abstract: A hunting detecting device used for an electrical load detecting device sets a current command value for an electrical load. Based on a deviation between a current that actually flows through the electrical load and the current command value, the hunting detecting device performs at least proportional control in a group including proportional control, integral control, and differential control. The hunting detecting device sends a current generated based on the performed control to the electrical load. A current determining device determines whether there is a current through the electrical load. When the current determining device determines that there is a current through the electrical load, a hunting detector detects a number of times of hunting within a predetermined period.

Abstract: An antiskid control system for a four-wheel-drive vehicle is arranged to calculate a difference between an average of wheel accelerations of front wheels and an average of wheel acceleration of rear wheels. When the difference is greater than or equal to the vibration determination threshold, the antiskid control system determines that a driveline vibration is generated and executes a control for converging the driveline vibration.

Abstract: A system is provided, which controls a starting and the subsequent vehicle acceleration procedure of a motor vehicle. The system compares a predetermined variable that grows continuously during the starting procedure to a threshold value. It determines a first desired value of torque in response to operator demand, and a second desired value torque in response to acceleration slip. The system performs a feed-forward 4WD control in response to the first desired value of torque when the predetermined variable is lower than or equal to the threshold value. The system determines whether or not driving situation justifies a change from performing the feed-forward 4WD control to performing a feed-back 2/4WD control in response to the second desired value of torque.

Abstract: Method and electronic control system using a unique driver demand (calibration) table stored in system memory to provide torque output values specific to a 4×4 mode of operation of the vehicle drive unit. For example, the torque output of the electronic control system for a 4×4 low mode of operation is controlled using a unique calibration table stored in system memory for 4×4 low mode of operation, while the torque output of the electronic control system for other modes of operation is controlled using one or more different, other calibration tables stored in system memory.

Abstract: A torque distribution control device for a four-wheel drive vehicle is disclosed, wherein a torque transmitted from an engine to prime drive wheels is distributed by an electromagnetic clutch to sub-drive wheels on an on-demand basis. A pre-torque is determined based on a vehicle speed and a throttle opening degree in a feed-forward sense. A compensation torque is determined based on the rotational speed difference between the prime drive wheels and the sub-drive wheels and the vehicle speed in a feedback sense. The pre-torque and the compensation torque are added for a command torque, depending on which the electromagnetic clutch is controlled to transmit the torque from the engine to the sub-drive wheels.

Abstract: An electronic control system for a vehicle includes a plurality of input devices, a plurality of output devices, a communication network, and a plurality of interface modules. The plurality of input devices may include a first input device that provides information pertaining to an angular position of a first vehicle wheel. The plurality of output devices may include an actuator capable of adjusting one or both of the angular position of the first vehicle wheel or an angular position of a second vehicle wheel. The plurality of interface modules can be microprocessor based and can be interconnected to each other by way of the communication network. The plurality of interface modules may also be coupled to the plurality of input devices and to the plurality of output devices. The plurality of interface modules may include one or more interface modules that is coupled to the first input device and to the actuator.

Abstract: A torque-biasing system (10) including a torque-biasing device (12) and a control unit (14) for use in a vehicle (16). The torque-biasing system is preferably installed and used in a vehicle having a first wheel (18) with a first rotational speed and a second wheel (20) with a second rotational speed, and an engine (22) with a torque output. The control unit (14) calculates an error value based on a different between the first rotational speed and second rotational speed and derives a control signal based upon proportional and integral terms of the error value with a forgetting factor. The control unit then sensor the control signal to the torque-biasing device (12).

Abstract: In a differential limiting torque control section, a target differential rotation speed between front and rear drive shafts is established according to a dial position inputted by a driver of a variable dial. Further, an actual differential rotation speed between front and rear drive shafts is calculated and a deviation between the target differential rotation speed and the actual differential rotation speed is calculated. Based on the deviation, a first differential limiting torque and based on a dial position of a variable dial a second differential limiting torque are calculated. Further, a third differential limiting torque is calculated based on the dial position and a throttle opening angle. A final differential limiting torque between front and rear drive shafts is obtained by summing up these first, second and third differential limiting torques.

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: A traction distribution control system for a 4WD vehicle is constructed to calculate a difference gain in accordance with a difference in spinning state between main driving wheels, and determine a control signal for controlling traction distribution to driven wheels by multiplying a control amount by the difference gain.

Abstract: A torque-biasing system (10) includes a torque-biasing device (12) and a control unit (14) for use in a motor vehicle. The torque-biasing system is preferably installed in a vehicle having a first front wheel (18) with a first rotational speed and second wheel (20) with a rear rotational speed and an engine (22) with a torque output. The control unit (14) functions to determined when and how to bias the torque output of the front and rear wheels, and to control the torque-biasing device (12) based on this determination.

Abstract: A traction distribution control system for a 4WD vehicle is constructed to calculate a difference gain in accordance with a difference in spinning state between main driving wheels, and determine a control signal for controlling traction distribution to driven wheels by multiplying a control amount by the difference gain.

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: In a motor vehicle driveline including a transfer case whose output is continually connected to a first output, a clutch, operating partially engaged, responds to a control signal to change the degree of clutch engagement, whereby a second output is connected driveably to the first output. A digital computer, repetitively executing a computer readable program code algorithm for operating the clutch partially engaged, continually selects a desired magnitude of clutch engagement with reference to functions indexed by vehicle speed and either engine throttle position or engine throttle rate. The computer repetitively updates at frequent intervals the desired degree of clutch engagement, and issues a command clutch duty cycle to a solenoid-controlled valve, which signal changes the degree of clutch engagement in response to the command signal.

Abstract: A system and method of controlling a multi-wheel drive vehicle is provided. The invention is preferably applicable to the steering of such a vehicle and determines the individual velocities for each wheel drive. In this regard, the invention includes two general steps. The first step includes determining the distance of each wheel drive and a vehicle velocity reference point from a turning reference point. The second step includes ratioing each wheel drive's distance from the turning reference point with the vehicle velocity reference point's distance from the turning reference point. The ratios are then applied to a vehicle velocity associated with the vehicle velocity reference point to determine the velocity of each respective wheel drive. Once determined, the velocities are output to each wheel drive.

Abstract: An improved method of operation for a motor vehicle automatic transmission determines a vehicle speed for purposes of selecting a desired transmission gear at least in part based on the wheel speeds of the vehicle. If the vehicle is being operated in a two-wheel drive mode, the vehicle speed is determined based on an average of the speeds of the un-driven wheels; if the vehicle is being operated in a four-wheel drive mode, the vehicle speed is determined based on the lowest of the four wheel speeds. Optionally, the wheel speeds are only used to determine vehicle speed if the Reverse range of the transmission has been engaged within a specified time interval, and otherwise the vehicle speed is determined based on an output speed of the transmission.

Abstract: In driving force controlling apparatus and method for a four-wheel drive vehicle, a driving force distribution controller determines whether there is a vehicular driver's demand on the driving force, calculates a driving force distribution ratio between front and rear road wheels in such a manner that a driving force distribution rate for auxiliary driven wheels is updated to its maximum value on the basis of a slip quantity of main driven wheels when determining that there is the vehicular driver's demand on the driving force, calculates another driving force distribution ratio therebetween in accordance with the acceleration slip quantity when determining that there is no vehicular driver's demand on the driving force, and is operated to adjust variably the driving force therebetween in such a manner that the driving force distribution ratio between the front and rear road wheels indicates that calculated by either one of the above-described two methods.

Abstract: When vehicle behavior control systems such as VDC, TCS, ABS and the like are operative, a front-rear power distribution control apparatus for a four wheel drive vehicle can have an excellent convergence characteristic in vehicle behavior control by choosing a transfer clutch torque from a region of a predetermined table in which the power distribution control does not interfere with the behavior control of the vehicle behavior control system and by establishing the transfer clutch torque to a larger value with an increase of transfer input torque. When the vehicle is in an understeer or oversteer tendency, the convergence of vehicle behavior is further enhanced by correcting the transfer clutch torque in an increasing or decreasing direction.

Abstract: The differential limiting control apparatus having a clutch unit interposed between one rotational shaft and the other rotational shaft for variably transmitting a driving force between the one rotational shaft and the other rotational shaft, having: a feedback control unit for computing the clutch torque on basis of vehicle behaviors through a feedback control, a feed forward control unit for computing the clutch torque based on the behaviors through feed forward control, a tire diameter difference computing unit for computing a diameter difference of a tire, and a clutch torque computing unit for computing a final clutch torque by changing a ratio of the clutch torque obtained through the feedback control and a clutch torque obtained through the feed forward control so as to appropriately decide the feed forward control by effectively suppress the tire slip while avoiding the occurrence of the internal circulation of the torque.

Abstract: A temporary indicated torque is obtained by taking a conventional dead zone area for a first slip control area, and the value proportional to the slip quantity for a maximum value, this temporary indicated torque is corrected by a correction value according to the tight cornering brake quantity to be the indicated torque of the transfer clutch, and occurrence of any tight cornering brake phenomenon is prevented thereby. In a slip control area after passing a dead zone area (a second slip control area), the slip control is smoothly transferred from the first slip control area to the second slip control area by performing the slip control with a value of the indicated torque according to the slip quantity added to the indicated torque in the first slip control area as the indicated torque, abrupt torque change is prevented, and the vehicle behavior is stabilized thereby.

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 in which the engine output is transmitted to front wheels and to rear wheel through a transfer clutch. The control unit determines a road gradient from the output value of a longitudinal acceleration sensor at a stop, sets a lower limit on the basis of the road gradient and is prepared for a start by outputting a drive signal corresponding to lower limit to a clutch control valve for controlling the applying force of the transfer clutch. Thus, the applying force is set according to the road gradient so that the main drive wheels at the slope can be prevented from slipping by the minimum transmission torque.

Abstract: A method for redistributing driving torque between front and rear driving wheels of a vehicle traveling at essentially the same speed. The method includes determining a vehicle condition corresponding to load, based upon at least one vehicle parameter, comparing the determined vehicle condition to a predetermined value, wherein if the determining vehicle condition exceeds the predetermined value, a high load condition exists, and redistributing the driving torque between the front and rear wheels, when the determining step determines that a high load condition exists. By controlling torque redistribution in accordance with one or more high load conditions on the driveline components, subsequent damage of the driveline system can be reduced or prevented.

Abstract: A power distribution control system for a vehicle, in which a front/rear drive-force distribution control unit computes a torque-response-torque, a revolution-difference-response-torque and a yaw-rate feed back torque. When a torque down command by a traction control is not outputted to an engine control unit, and a braking force control is not active, a transfer clutch torque is setted as defined by a predetermined equation.

Abstract: A traction distribution control system for a 4WD vehicle is so constructed as to carry out traction distribution control to increase distribution of traction to the driven wheels when a speed difference between the main driving wheels and the driven wheels exceeds a control threshold value, detect constant-speed run of the vehicle, and carry out correction control to correct the control threshold value in accordance with the wheel-speed difference when constant-speed run is detected.

Abstract: A four-wheel drive vehicle in which the engine output is transmitted to front wheels and to rear wheel through a transfer clutch. The control unit determines a road gradient from the output value of a longitudinal acceleration sensor at a stop, sets a lower limit on the basis of the road gradient and is prepared for a start by outputting a drive signal corresponding to lower limit to a clutch control valve for controlling the applying force of the transfer clutch. Thus, the applying force is set according to the road gradient so that the main drive wheels at the slope can be prevented from slipping by the minimum transmission torque.

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 vehicle is equipped with a coupling such as, for example, a center differential or a variable clutch, that transmits a driving force from an engine to a front-wheel drive shaft and a rear-wheel drive shaft while allowing a difference in rotational speed therebetween and a brake controller that individually controls braking forces to be applied to wheels in accordance with a running state of the vehicle. A vehicular brake controller prohibits braking force control from being started if the coupling is in its locked state or when the coupling causes a relatively great connecting strength to exist between the front-wheel and rear-wheel drive shafts. While braking force control is being performed by the brake controller, braking force control is continued even if there is a command to cause the coupling to be locked or to achieve the great coupling strength.

Abstract: The invention provides a method of progressive engagement of all-wheel drive for a mobile vehicle. A set of vehicle parameters is sensed, and an all-wheel drive lock value is determined based on the sensed set of vehicle parameters. Vehicle subsystem control activation is determined, and the all-wheel drive lock value is adjusted based on the vehicle subsystem control activation determination. An all-wheel drive controller is engaged based on the adjusted all-wheel drive lock value.

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: In driving force controlling apparatus and method for a four-wheel drive vehicle, a command is outputted to a front-and-rear wheel driving force distribution control system to reduce a clutch engagement force of a clutch such as a frictional clutch when a subtraction value of a detected value of a clutch transmission torque from that of a clutch input torque (Tinp−Tr) is smaller than a predetermined value (&dgr;) and detected wheel velocities of both of left and right road wheels of the vehicle are substantially equal to each other (Vw1±&agr;=Vw2 and Vw3±&agr;=Vw4).

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 drive-force distribution controller for a four-wheel-drive vehicle having a torque distribution unit configured to distribute an output torque transmitted from a prime motor to a first set of wheels to a second set of wheels. The drive-force distribution controller includes a first judging device for judging which of the first set is an inner wheel with respect to a turning of the vehicle, a second judging device for judging whether the turning of the vehicle is a tight turn, a third judging device for judging whether the inner wheel is slipping, a fourth judging device for judging whether an outer wheel of the first set of wheels is slipping, and a controlling device for controlling the torque distribution unit.

Abstract: In case there occurs a wheel slip in either one of front left and right wheels or rear left and right wheels, a traction control through an engine output and a traction control through braking are implemented. Furthermore, in case the vehicle speed is slow, a final limited slip differential torque is set by adding a limited slip differential compensation amount according to a steering angle to a limited slip differential torque set according to an inputted torque and a front/rear differential rotation, and further adding thereto a limited slip differential compensation amount according to the vehicle speed for increasing the compensation.

Abstract: A control system or apparatus (10) is provided which is deployed within a four-wheel drive vehicle (12) and which is adapted to automatically control the activation and deactivation (i.e., locking and unlocking) of hub locks (44) according to a certain control strategy. Hub locks (44) are effective to operatively connect and disconnect the front wheels (14) of vehicle (12) to the front axle assembly (16), thereby allowing torque from the front driveshaft (22) of the vehicle to be transferred to the front wheels (14) when the vehicle (12) operates in a four-wheel drive mode. Control system (10) is effective to detect system faults and malfunctions and to selectively alter the hub locks control strategy in response to such a detection, thereby substantially preventing the undesired locking/unlocking of the hub locks (44) resulting in possible ratcheting, binding or damage to the hub locks (44).

Abstract: A vehicle control apparatus for controlling a four-wheel-drive automotive vehicle of a type which comprises a first drive power source for driving one of a pair of front wheels and a pair of rear wheels, and a second drive power source for driving the other of the pairs of front and rear wheels, wherein an operator's desired value of a vehicle drive force for driving the automotive vehicle is obtained on the basis of an amount of operation of a manually operated vehicle accelerating member and a running speed of the vehicle, and a front drive force for driving the pair of front wheels and a rear drive force for driving the pair of rear wheels are controlled on the basis of a static and a dynamic state of the vehicle such that a sum of the front drive force and the rear drive force is equal to the obtained operator's desired value of the vehicle drive force.

Abstract: A friction coefficient on road is estimated for vehicles. An actual vehicle of a specific vehicle operating parameter is calculated. A first reference value of the vehicle operating parameter on a road with a large friction coefficient is calculated based on vehicle operating model for the road with the large friction coefficient. A second reference value of the vehicle operating parameter on a road with a small friction coefficient is calculated based on vehicle operating model for the road with the small friction coefficient. A friction coefficient on road is estimated based on the relationship between the actual value and the first and the second reference values.

Abstract: A system and method of controlling a multi-wheel drive vehicle is provided. The invention is preferably applicable to the steering of such a vehicle and determines the individual velocities for each wheel drive. In this regard, the invention includes two general steps. The first step includes determining the distance of each wheel drive and a vehicle velocity reference point from a turning reference point. The second step includes ratioing each wheel drive's distance from the turning reference point with the vehicle velocity reference point's distance from the turning reference point. The ratios are then applied to a vehicle velocity associated with the vehicle velocity reference point to determine the velocity of each respective wheel drive. Once determined, the velocities are output to each wheel drive.

Abstract: A method of electronic brake force distribution in a two-axle four-wheel vehicle 1 effects a compensation of the speed differences between left and right vehicle side during cornering. To this end, a compensation speed is calculated for the curve-inward rear wheel 6 and added to the individual wheel speed of the rear wheel 6 to be compared with a vehicle reference speed. The individual wheel reference speed of this wheel, which is this way increased in relation to the individual wheel speed of the curve-inward rear wheel 6, prevents a premature activation of electronic brake force distribution because the produced individual wheel reference speed is closer to the vehicle reference speed than the individual wheel speed. This permits better utilizing brake force during cornering.

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 transfer case 32. Controller 40 selectively transmits a torque control or minimum duty cycle signal to transfer case 32, which is at least partially based upon the angular position of the vehicle's steering wheel and the speed of driveshafts 22, 26.

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: A four-wheel drive anti-lock brake control in which the existence of torque transfer between the front and rear wheels of the vehicle is detected based on differences in the duration of ABS control used at each of the independently controlled wheels. Such differences are used to determine a ratio of rear-to-front (or front-to-rear) ABS control. If the ratio indicates the presence of torque transfer, the wheel causing the transfer is identified and its brake pressure released as required to alleviate the detected torque transfer, so long as the release will not cause a change in vehicle deceleration.

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: The present invention relates to a method and a device for adjusting the output torque or the output speed of an internal combustion engine in order to protect the differentials. The crux and advantage of the present invention lies in calculating and monitoring the rpm differences or the rpm differences in the transverse direction of any vehicle (front-wheel-, rear-wheel-, and four-wheel-drive) as well as the difference in the Cardan speeds that exists in the longitudinal direction in four-wheel drive vehicles. When a specifiable limiting value is exceeded, an automatic reduction in the drive torque or an automatic limiting of the engine speed to a manageable level takes place. This protective function for the differentials cannot be switched off and is available even in the passively activated drive-torque AMR control system. It can only be realized by software using already existing sensors and actuator devices. The application outlay is minimal.

Abstract: A process for continuously controlling the transfer of torque within a differential where a target delta (&Dgr;T) value is determined as a function of a first differential output shaft speed (&ohgr;a) and a second differential output shaft speed (&ohgr;b) and then normalized according to the vehicle speed when the vehicle is being driven under a no wheel slip condition. A normalized actual delta (&Dgr;A) is also determined as a function of the first output shaft speed (&ohgr;a) and the second output shaft speed (&ohgr;b), a comparison is made between &Dgr;T and &Dgr;A and torque is transferred between the first and second output shafts of the differential according to a logic control methodology such as proportional, integral, and/or derivative (PID) control methodologies if the comparison result of &Dgr;A to &Dgr;T is outside of a tolerance range established around &Dgr;T.

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: A device for changing the speeds of the front and rear wheels in a four-wheel-drive vehicle including a continuously variable speed-changing mechanism for the front wheels, which changes the input rotational speed and outputs it to the front wheel drive shafts, and a continuously variable speed-changing mechanism for the rear wheels, which changes the input rotational speed and outputs it to the rear wheel drive shafts. The device for changing the speeds of the front wheels and the rear wheels comprises a detector means for detecting the operation conditions of the vehicle, a steering angle sensor for detecting the steering angle of the vehicle, and a controller for variably controlling the speeds of the continuously variable speed-changing mechanisms based on the operation conditions of the vehicle.

Abstract: An apparatus and a method for estimating a vehicle speed of a vehicle in which a driving state can be switched between a four-wheel drive (4WD) state and a two-wheel drive (2WD) state. The driving state of the vehicle can be determined based on one or more pieces of information. A controller calculates the vehicle speed based on a wheel speed of at least one non-driven wheel when it is determined that the vehicle is in the 2WD state. When it is determined that the vehicle is not in the 2WD state or when it cannot be determined that the vehicle is in the 2WD state, the controller calculates the vehicle speed based on the lowest one and/or the second lowest one of the wheel speeds of all of the wheels. Further, an apparatus and method for performing predetermined control, such as behavior control or traction control, that perform the control by using the estimated vehicle speed.

Abstract: A device for influencing the propulsion of a vehicle includes a first arrangement for measuring a transverse acceleleration variable describing the transverse acceleration acting upon the vehicle, a second arrangement for determining a variable describing the time behavior of the transverse accelaretion variable, a third arrangement for determining an intervention variable at least as a function of the transverse acceleration variable and of the variable describing the time behavior of the transverse acceleration variable, and a fourth arrangement for carrying out at least engine interventions for influencing the propulsion as a function of the intervention variable.