Abstract: An arrangement for controlling the rotational speed of an output rotational part of a fluid friction coupling is provided. A fan for cooling components of a motor vehicle is coupled with a driving rotational part by way of a shearing fluid whose effective fluid quantity determines the transferrable torque. The arrangement contains an adjusting unit (which can be electrically driven in a timed manner) for the variable adjustment of the effective shearing fluid quantity and contains a temperature controller stage to which the temperature of at least one medium whose temperature can be influenced by the output rotational speed is fed. The invention, the temperature controller stage is followed by a rotational speed controller stage to which, on the input side, the output signal of the temperature controller stage is fed as the dessired rotational output speed as well as the rotational driving speed and which, via of its output signal, drives the shearing fluid quantity adjusting unit of the coupling.

Abstract: This invention relates to an automatically controlled clutch in a motor vehicle drive train. Rotational speed differences between the clutch input and the clutch output are determined by a computer from rotational speeds of the vehicle engine, on the one hand, and rotational speeds of the vehicle drive wheels, on the other hand. Variations of a frequency which is characteristic of resonant frequencies in the drive train when the clutch is closed are not taken into account.

Abstract: A protecting device for a car air conditioner includes a timer for timing a period of the rise in the level of a rotation signal delivered from a rotation sensor for detecting a rotational speed of a compressor with the signal being distinguished from noise. On the basis of the obtained period, a judgment is made as to whether rotation of the compressor is in an abnormal state. An electromagnetic clutch between the compressor and a car engine is controlled on the basis of the judgment. The protecting device is mounted on a housing of the compressor with the rotation sensor so that wiring is executed only in an engine room. The protecting device includes a state holding device for memorizing the abnormal state of the rotation of the compressor. The air conditioner can restart on condition that a conscious operation is performed to reset the state holding device.

Abstract: A two wheel drive motorcycle is provided with an unsteerable rear wheel, a steerable front wheel, a drive unit having a driving motor for driving the rear wheel and a transmission device coupled to the drive unit for driving the front wheel. The transmission device has a hydrostatic drive having a hydraulic pump driven by the driving motor and whose hydraulic motor is mounted on an arm of the front fork. The hydraulic pump has constant output and the hydraulic motor has a constant input matched to the pump output. Hydraulic fluid is delivered from the hydraulic pump to the hydraulic motor by a pressure line. The pressure in the pressure line is controlled by a pressure control valve which can be adjusted to maintain a pressure in the range of approximately 20 to 200 bars.

Abstract: A fluid clutch comprises a driving disc rotationally driven by a driving section, a rotatable casing enhousing the driving disc, a blower attached to the casing, and an oil supply means for supplying an oil from an outside to a torque transmission gap between the driving disc and the casing. Further, a driving section may be connected by means of a flexible joint to either one of the casing or the disc. The fluid clutch can always attain optimum control by adjusting the amount of the oil at a high accuracy and rapidly depending on various kinds of operation conditions. A breezer also is provided for releasing gas from the torque transmission chamber when pressure exceeds a predetermined upper limit, and for enabling inflow of atmospheric air to the torque transmission chamber when pressure is less than a predetermined lower limit. The clutch is endurable to external vibrations.

Abstract: A system for discriminating operation state of a lockup clutch of a torque converter of a transmission of a vehicle, more particularly to a system for detection a lockup clutch failure. In the system, three discrimination areas are preestablished with respect to the throttle opening and vehicle speed and reference value are determined in response to a selected discrimination area. The converter slip ratio is compared with the data and when the ratio is out of a range determined by the data, the lockup clutch operation is discriminated to be not normal. At that time, however, when the area is in a weak-engaged region, the engaging force is forcibly increased and the discrimination is conducted once again, thereby making it possible to conduct failure detection in the slip-engaged region and enhancing detection accuracy.

Abstract: A control for a vehicular automated clutch (14) drivingly interposed between a fuel-controlled engine (12) and a multiple-speed, change-gear transmission (16) providing enhanced low-speed maneuvering control is provided. Upon manual selection (40) of creep mode, an enhanced creep mode is activated, effective over a relatively large range (0% to 75%) of throttle pedal (32) displacement.

Abstract: A control device for regulating the engaging process of a separating clutch for motor vehicles for automatically reducing the rpm difference between the driven clutch element and the driving clutch element and/or to regulate the disengaging process of a separating clutch includes a device for detecting the driving rpm and a device for axial adjustment of at least one clutch element of the separating clutch.

Abstract: A method of controlling a viscous fluid coupling (15) in which, when the vehicle engine (E) is operating at low speeds, if the speed of rotation (SF) of the fan exceeds a predetermined speed limit (L3), the input signal (29) to the coupling is modified to move the valve member (49) toward a closed position (FIG. 3A). This action reduces the occurrence of an overfill condition, thus reducing undesired fan noise when the engine again accelerates. Another aspect of the invention is to sense the speed (SE) of the engine, and whenever the sensed speed (SE) is high enough that operation in an excess slip heat region (ESH) is possible, compare the demanded fan speed (29) to the lower limit (CHP) of the slip heat region. Whenever the demanded fan speed exceeds the limit, the input signal (29) to the coupling is modified to operate the coupling at a speed safely above or below the slip heat region (ESH) depending on the state of control inputs such as engine temperature.

Abstract: A free-wheeling coupling sensitive to the direction of rotation for a motor vehicle comprises a first ring which constitutes a driving element in a towing mode of the motor vehicle, a second ring which constitutes a driven element in the towing mode, clamping elements which act between the first and second rings to transfer torque in both directions of torque flow, a cage in which the clamping elements are disposed, a fixed friction ring, and a friction element actively connecting the cage to the fixed friction ring. The friction element comprises a plurality of friction segments disposed between the cage and the fixed friction ring, the friction segments being slaved to rotate in the circumferential direction with the cage and being lifted away from the fixed friction ring by centrifugal force when they are caused to rotate at a rotational speed which is greater than a predetermined rotational speed.

Abstract: An apparatus that detects a reference position of a throttle valve. The throttle valve is forced in either a valve opening direction or a valve closing directions by an urging member. A DC motor, which is connected to the throttle valve, drives the throttle valve against the force created by the urging member within a rotatable angle that is restricted by a stopper. A throttle valve opening sensor detects an opening angle of the throttle valve. A lock current detecting circuit detects a lock current created by the DC motor when the DC motor is brought into contact with the stopper. A throttle valve reference position renewing circuit updates the reference position, which is memorized in a throttle valve reference position memory, on the basis of an opening angle of the throttle valve, which is detected by the throttle valve opening sensor, when the lock current detecting circuit detects the lock current.

Abstract: An automatic clutch controller for a vehicle that reduces the oscillatory response to clutch engagement. The automatic clutch controller receives inputs from an engine speed sensor and a transmission input speed sensor and develops a clutch actuation signal controlling a clutch actuator from disengaged to fully engaged. The clutch engagement signal at least partially engages the friction clutch in a manner to cause the measured transmission input speed to asymptotically approach engine speed employing an approximate inverse model of this oscillatory response. The automatic clutch controller preferably includes a PID function and a differential engine speed function, which together adaptively adjust clutch engagement corresponding to vehicle loading.

Abstract: An automatic transmission on an automobile is combined with a friction clutch coupled between the output shaft of an engine and the input shaft of the automatic transmission. The friction clutch is controlled selectively for engagement and disengagement by an electric actuator. The electric actuator is controlled by a controller to engage the friction clutch in a feedback loop such that the rate of change of the rotational speed of the engine is zero when the power from the engine starts to be transmitted by the friction clutch to the automatic transmission.

Abstract: A vehicle clutch engagement position is disclosed wherein the clutch is moved, under computer control, at a constant rate, from a disengaged position toward a fully engaged position while the transmission is in neutral gear, and the position of the clutch is detected at first and second times (T1 and T2). Time T1 corresponds to the time when the detected speed of the transmission input shaft is just above the dropout speed of the input shaft speed sensor. Time T2 corresponds to the time when the detected speed of the input shaft is close to engine speed. The position of the clutch corresponding to the incipient torque point is extrapolated by subtracting an offset amount from the position detected at time T1. The offset is equal to the change in position from T1 to T2 multiplied by the square root of the ratio of the input shaft speeds at T1 and T2.

Abstract: An automatic clutch controller for a vehicle that reduces the oscillatory response to clutch engagement. The automatic clutch controller receives inputs from an engine speed sensor and a transmission input speed sensor and develops a clutch actuation signal controlling a clutch actuator from disengaged to fully engaged. The clutch engagement signal at least partially engages the friction clutch in a manner to cause the measured transmission input speed to asymptotically approach engine speed employing an approximate inverse model of this oscillatory response. The automatic clutch controller preferably includes a slip integral function and a differential engine speed function, which together adaptively adjust clutch engagement corresponding to vehicle loading. The automatic clutch controller includes a prefilter and a compensator constructed to reduce the need for detailed particularization for individual vehicles or vehicle models.

Abstract: A control for enabling a clutch to be automatically engaged with a power source. An apparatus for automatically controlling the position of a clutch between a power source and a drive train characterized by a control which regulates pressure to a clutch engaging member according to performance criteria of the power source.

Abstract: There is provided a clutch/brake unit having aligned input and output shafts, clutch disks partially immersed in oil carried by the input shaft, brake disks partially immersed in oil fixed to the housing, and two series of friction disks also partially immersed in oil each series of friction discs secured to the output shaft and each series engagable by separate DC voltage coils. A fan is provided which is rotatable with the input shaft to provide cooling air to the clutch/brake unit. The operation of the clutch/brake unit is controlled by a computer which controls the relationship of the output shafts speed in relation to time.

Abstract: For the protection of an automatized friction clutch of a motor vehicle it is proposed, by means of a computer device (23) to compute periodically data for the instantaneous friction performance of the clutch (5) and to add them up in several also periodically actualized time window stores. The time window stores have different time windows and correspondingly store a range of friction work mean values. Associated with the individual time window stores are respectively several limit values, the magnitude is additionally a function of the air temperature of a clutch casing (37) surrounding the clutch (5). A computer device (23), depending upon the temperature measured by means of a temperature sensor (35) and upon the limit values ruling for this temperature, institutes graded protective measures. For safety reasons, none of the protective measures completely prevents the operativeness of the clutch (5).

Abstract: The invention relates to a transmission device between two coaxial rotating members (1; 10), of the type comprising a viscous-fluid coupling (11) with a driving element and a driven element, and control devices for modifying the operating characteristic of this coupling. It is defined, in particular, in that the control devices are incorporated into the transmission device and act as a function of the rotational speed of one the said members and as a function of a torque transmitted by the device. The control devices can comprise flyweights (21) which are rotationally integral with the member (1) and with the case (12) of the viscous-fluid coupling, these flyweights acting to modify the internal pressure in the coupling (11), via shuttles (27) and a sliding sleeve (8) which is displaced as a function of the torque transmitted between the sun gear (2) and the output shaft (10). This sliding sleeve can, for example, act on a plate (16) which modifies the spacing between the disks (14, 15) of the coupling.

Abstract: An automatic clutch controller for a vehicle that reduces the oscillatory response to clutch engagement. The automatic clutch controller receives inputs from an engine speed sensor and a transmission input speed sensor and develops a clutch actuation signal controlling a clutch actuator between from disengaged to fully engaged. The clutch engagement signal at least partially engages the friction clutch in a manner to cause the measured transmission input speed to asymptotically approach a reference speed employing an approximate inverse model of this oscillatory response. In a launch mode, corresponding to normal start of the vehicle, the reference speed is the measured engine speed. In a creep mode, corresponding to slow speed creeping of the vehicle, the reference speed is a creep speed reference based on the throttle setting and the engine speed. The two modes are selected based upon the throttle setting.

Abstract: There is proposed an assembly for damping vibrations in a torque transmitting arrangement between an engine and an input part of a transmission. The assembly comprises a first flywheel connected to the engine, and a second flywheel connectable to the input part of the transmission. The first and second flywheels are rotatable relative to each other. At least one damper includes spring means operative to resiliently oppose rotation of the flywheels relative to each other. The assembly also comprises at least one lock-up mechanism including centrifugal force responsive means operative to prevent rotation of the flywheels relative to each other after the damper has become idle when rotation of the engine is lower than a predetermined speed value.

Abstract: A force transmission linkage for an automotive vehicle couples a control member with a maneuvering member of a declutching device for a clutch, and is of the kind comprising a mechanical part with application points carried by a fixed part of the vehicle.In accordance with the invention, one of the application points of the linkage is movable in both directions along a course of travel which is defined between two limit positions and under the action of an irreversible control device driven by a motor. At least one position sensor is associated with the control member and with the movable application point, respectively. A computer is provided, for receiving the information signals from the position sensors so as to control the motor of the control device.

Abstract: A force transmission linkage for an automotive vehicle couples a control member with a manoeuvring member of a declutching device for a clutch, and is of the kind comprising a mechanical part with application points carried by a fixed part of the vehicle.In accordance with the invention, one of the said application points of the linkage is movable under the action of a control device comprising a motor and a transmission acting between the said motor and the said movable application point. A sensor for detecting a supplementary strain in the linkage, is provided together with a computer, with the computer receiving information signals from the strain sensor for control of the motor.

Abstract: A clutch device for phase-synchronous coupling of rotating machine elements, includes two coding elements, respectively, co-rotatable with two driven machine elements, a sensor fixed in position adjacent the coding elements, the coding elements having codings thereon which are variable in angular position with respect to the sensor, the sensor having a device for registering information composed from respective codings of the two coding elements, and a clutch control unit connected to the sensor for receiving the information therefrom.

Abstract: A soft start controller for regulating the engagement and disengagement of an electromagnetic clutch is disclosed. The controller includes a microprocessor which, in response to an engagement signal, causes electrical current to be provided to a coil of the clutch. A plurality of sensors are provided for generating electrical signals which are representative of various operating conditions of the clutch, such as engine load, clutch temperature and the like. These signals are selectively fed through a multiplexer and an analog to digital converter to the microprocessor. The microprocessor samples the signals generated by the sensors and controls the magnitude of the current fed to the coil of the clutch in response thereto. A plurality of manually operable start select switches are provided for selecting one of a plurality of clutch current curves stored in a memory of the microprocessor for use.

Abstract: A transmission includes a control unit which controls engagement/disengagement of an electromagnetic clutch such that it is disengaged when it is detected that a vehicle is at a stop, and such that the vehicle creeps at a predetermined speed when pressing of an accelerator pedal is detected.

Abstract: A system and method for controlling a friction clutch of a motor vehicle wherein conditions of the clutch, an engine, a transmission, and the vehicle are detected. A desired shifting speed for shifting a pressure plate of the clutch is provided based on the detected conditions. An actual shifting speed is estimated based on the desired shifting speed, and a position of the pressure plate is obtained by integrating the actual shifting speed. Speed of the pressure plate is controlled based on the position of the pressure plate.

Abstract: A clutch control unit includes a clutch learning unit (4b) for determining a clutch connection characteristic (M) based on the clutch position at which the number of revolutions of an output shaft of the clutch reaches a predetermined value when the clutch is moved toward connection from a predetermined learning starting point and a clutch off detector (4c) for determining a clutch off point at which the number of revolutions of the output shaft is zero by moving the clutch toward disconnection and taking as a new learning starting point the clutch off point or a point made by adding a small offset value to the clutch off point, thereby controlling the clutch based on the clutch connection characteristic (M).

Abstract: In a control system for controlling a clutch coupled with an internal combustion engine for driving a vehicle off, the control operation for clutch engagement is carried out based on the level of power insufficiency of the engine. When the level of engine insufficiency is within a predetermined range, the operation for clutch engagement is controlled in accordance with the change in the amount of operation of an accelerating member without stopping the engaging operation of the clutch. In order to improve the performance experienced by the operator at drive-off, just after recovery from power insufficiency, the target clutch stroke to be followed is corrected by correction data determined on the basis of the difference between the target and actual clutch stroke at the time the engine has just recovered from its power insufficiency.

Abstract: A device for automatic actuation of a friction clutch in the transmission line of a motor vehicle between an internal combustion engine and a change-speed gear, including a setting drive system for positioning a clutch releaser of the friction clutch in dependence upon an ideal-position signal, an engine rotation rate sensor which generates an engine rotation rate signal corresponding to the rotation rate of the internal combustion engine, a sensor device generating a gear rotation rate signal corresponding to the input rotation rate of the change-speed gear, and a control system responding to the engine rotation rate sensor and controlling the setting drive system for the engagement and disengagement of the clutch, the control system, for the engagement of the clutch in the starting of the motor vehicle, generates the ideal position signal according to a predetermined characteristic in dependence upon the engine rotation rate signal, and increases the ideal-position signal, in dependence upon the engine rota

Abstract: A soft start, self-powered coupling for connecting a motor to a load, the coupling including a magnetic particle clutch, a generator having a rotor carried by the clutch and a stator, and an electronic control circuit assembly carried by the generator rotor, the magnetic particle clutch being connector to the motor and to the load, the generator powering the electronic control circuit assembly and the clutch to provide linear timed acceleration of the load.

Abstract: A differential gear unit for the drive axles of motor vehicles has a positive differential lock comprising a jaw clutch plate which is connected non-rotatably but movable axially with the differential case and which works in conjunction with a jaw clutch counterplate which is mounted non-rotatably and axially immobile on a differential gear drive shaft. The jaw clutch plate also serves as an armature for an electromagnet shaped as a ring magnet, which can be switched on and off manually. The jaw clutch plate is released from the jaw clutch counterplate by the preloaded spring means when the ring magnet is switched off. The electric circuit for controlling the ring magnet includes an electronic control unit developed as a velocity sensor which allows switching on of the ring magnet only below a predetermined velocity limit of the vehicle. Above this velocity limit the ring magnet switches off automatically.

Abstract: A system for controlling a clutch has an engine speed sensor for producing an engine speed signal and a controller for controlling the torque of the clutch at start of a vehicle in accordance with engine speed. An atmoshperic pressure sensor is provided for detecting the atmospheric pressure. In accordance with the detected atmospheric pressure at high altitude, the torque of the clutch is reduced.

Abstract: A system for controlling an electromagnetic clutch for a motor vehicle at transient state of driving condition of the motor vehicle. An actual engagement ratio is obtained in dependence on speeds of a drive member land a driven member of the clutch. A desired engagement ratio of the clutch is obtained in accordance with the speeds of the drive member and driven member. Clutch current is controlled so as to converge the actual engagement ratio on the desired engagement ratio. The transition of the change of the actual engagement ratio is observed and a correction signal is generated when the actual engagement ratio does not change in a converging direction. The clutch current is corrected by the correction signal.

Abstract: A device for detecting when a driven apparatus has frozen and/or its prime mover coupling mechanism is slipping. The rotational speed of the driven apparatus is detected and a corresponding speed signal is compared to a reference speed signal. The reference speed signal corresponds to a speed slightly lower than the idling speed of the prime mover. When the detected speed signal is lower than the reference speed single, slippage in the prime mover coupling mechanism is presumed and a slippage signal is provided. The slippage signal may be used to control the coupling mechanism to disengage the apparatus from the prime mover to prevent damage from occurring.

Abstract: Disclosed is a control method for a magnetic powder clutch system including a magnetic powder clutch having an input shaft connected to an engine and an output shaft. In the method, the magnetic powder clutch is energized by an energizing strength which is determined based on a transmitting torque. The energizing strength is compensated with a predetermined correction factor to realize the control in high accuracy. Moreover, the correction factor is always updated in response to an error between the target engagement revolution speed and the detected actual engagement revolution speed. By correcting the energizing strength to diminish the error, the magnetic powder clutch is correctly engaged at the target engagement revolution speed.

Abstract: A motor vehicle comprises a primary driven axle and a secondary driven axle which is adapted to be arbitrarily driven under the control of an electric control device. In order to ensure a more reliable handling of the vehicle during a braking, the electric control device comprises a switch, which is arranged to be automatically enabled in response to a rise of the speed of travel of the vehicle to a predetermined value and which in an enabled state is arranged to respond to a braking operation or a predetermined braking operation by a disabling of the drive train leading to the secondary driven axle and to maintain the drive train disabled, and an additional switch, which is manually operable to enable the drive train.

Abstract: A system for controlling a drag torque of an electromagnetic clutch at releasing of an accelerator pedal of a motor vehicle with a continuously variable belt drive transmission. A detector is provided for detecting whether vehicle speed is lower than a predetermined low speed. At the low vehicle speed, the drag current is gradually reduced as the vehicle speed increases.

Abstract: A system for controlling a drag torque of an electromagnetic clutch at idling operation of an engine for a motor vehicle with a continuously variable belt drive transmission. A detector is provided for detecting whether engine speed is higher or lower than a predetermined minimum idling speed. When the engine speed is at a higher engine speed, a standard current is passed in a coil of the clutch. At a lower idling speed, the drag current is gradually reduced until the engine speed increases to the predetermined minimum idling speed.

Abstract: A viscous fan clutch (10) is typically employed in a fan drive mechanism within a truck or automobile. A shaft (18), driven by the engine (12), rotates a clutch member (42) within the fan drive. The clutch member is arranged for fluid engagement with a body member (60) for the transmission of torque thereto when fluid is disposed in an operating chamber (106) defined by complimentary shear surfaces in the clutch and body members (48 and 98), respectively. A tether assembly (30) operates as an actuator to displace a valving element (196) within the clutch to control the torque transmission there through and thus the speed of the output shaft and fan (34) thereof. Fan speed is regulated by variable current signal applied to a coil (174) within assembly (30) to selectively variably frictionally engage valve element assembly (196) with a grounded thrust surface or reaction member (190) to effect limited displacement of a valve element (198) in response thereto.

Abstract: A system for disengaging an electromagnetic clutch of a vehicle at rapid deceleration of the vehicle. The rapid deceleration is detected by changing rate of engine speed when the magnitude of deceleration is larger than a reference value, the electromagnetic clutch is disengaged at an engine speed which is higher than idling speed.

Abstract: A clutch brake having a hub flange with a brake assembly installed between two cover elements forming a cover assembly, external friction surfaces on the cover elements, recessions formed on an outer peripheral part of the hub flange, centrifugal segments urged by a centrifugal force toward radial outsides of the hub flange installed in the recessions and spring members in the recessions urging the centrifugal segments radially outwardly of the recessions for generating an initial torque between the centrifugal segments and the hub flange.

Abstract: A system for controlling a drag torque of an electromagnetic clutch at releasing of an accelerator pedal of a motor vehicle. A detector is provided for detecting whether vehicle speed is lower than a predetermined low speed. At the low vehicle speed, drag current is corrected in dependency on engine speed so as to provide a constant drag torque.

Abstract: A system has a start mode in which clutch torque of the clutch increases with increase of speed of an engine of the motor vehicle, a lock-up engagement mode in which the clutch torque is increased, and a drag mode in which the clutch torque is reduced to produce a drag torque, one of the modes being selected in accordance with depression of the accelerator pedal and speed of the vehicle. When a vehicle speed detector does not produce a vehicle speed signal for a predetermined period in the start mode at engine speed higher than a predetermined speed, a fail-safe signal is produced. In response to the fail-safe signal, the system operates to keep clutch torque.

Abstract: A clutch control system provides and regulates pressure at a clutch for transmitting torque from an engine to a drive train through a continuously variable transmission. A positive torque value is determined for each throttle setting and provided as a pressure input signal. Engine speed is monitored through a closed loop feedback system to provide an error signal to the desired pressure setting. A pressure control loop monitors pressure at the clutch through a closed loop feedback system to maintain the pressure at the clutch at a desired level. Filtering is provided in the torque and engine speed loops to provide for a more realistic response to driver demand. Incorporation of belt ratio factor in the engine speed control loop further provides for consistent and accurate response to driver demand variations at differing transmission drive levels. Overall line pressure within the associated hydraulic system further controls a proportional gain in the pressure control loop to provide appropriate response.

Abstract: There is disclosed an electromagnetic clutch having a rotation detecting device. The electromagnetic clutch has a balance weight which is disposed on the outer end surface of a hub connected to a driven shaft. The detecting device for detecting the rotation of the balance weight is located at the position which faces toward a circumferentially discontinuous part of the balance weight. The construction of the above mentioned electromagnetic clutch is very simple and easy to manufacture. Also, the rotation detecting device can be put on or removed easily.

Abstract: Apparatus for damping torsional vibrations in the power trains of motor vehicles has a first flywheel connected to the crankshaft of the engine and a second flywheel which is rotatable relative to the first flywheel and can be coupled to the input shaft of the change-speed transmission by a friction clutch. Angular movements of the flywheels relative to each other are opposed by a hydraulic damper, by an elastic damper and by a friction generating device. The hydraulic damper has pairs of chambers for a viscous fluid medium which is caused to flow from one chamber to the other chamber by way of one or more flow restrictors in response to angular movements of the flywheels relative to each other.

Abstract: A friction clutch controlling apparatus for controlling a friction clutch by an actuator has a detector for detecting slip rate of the friction clutch, and the detector detects an initial slip rate of the friction clutch at the start of the engaging operation of the clutch in response to a signal for commanding the engagement of the clutch. The operation for engaging the friction clutch is carried out by the actuator in such a way that the slip rate decreases from the initial slip rate to zero in accordance with predetermined slip rate control characteristics.

Abstract: A method and an apparatus of controlling an electromagnetic clutch incorporated in a power transmission system of a vehicle to transmit an output of an engine to the drive wheels of the vehicle is disclosed. An amount of electric current applied to the clutch is regulated to control an engaging action of said electromagnetic clutch, based on either a variation in rotating speed or torque of an output shaft of the electromagnetic clutch, or based on the frequency or number of variations per unit time in rotating speed or torque of the output shaft, as compared with the frequency or number of ignitions or combustions per unit time of the engine. In this way a variation in output torque of the engine is absorbed by the electromagnetic clutch for improved drivability, while a transmission power loss in the clutch is kept to a minimum for maximum fuel economy.

Abstract: A method and an apparatus of controlling an electromagnetic clutch incorporated in a power transmission system of a vehicle to transmit an output of an engine to the drive wheels of the vehicle is disclosed. An amount of electric current applied to the clutch is regulated to control an engaging action of said electromagnetic clutch, based on either a variation in rotating speed or torque of an output shaft of the electromagnetic clutch, or based on the frequency or number of variations per unit time in rotating speed or torque of the output shaft, as compared with the frequency or number of ignitions or combustions per unit time of the engine. In this way a variation in output torque of the engine is absorbed by the electromagnetic clutch for improved drivability, while a transmission power loss in the clutch is kept to a minimum for maximum fuel economy.