Abstract: A centrifugal clutch including a drive member, a plurality of intermediate members, a driven member and closing plates each having shape and weight conforming to a side wall of each intermediate member to provide dynamic balance for the clutch. When the drive member rotates sufficiently fast, the intermediate members move radially outward along respective parts of the drive member, against the bias of a peripherally extending spring held in place as to each intermediate member by the respective closing plate.

Abstract: A four wheel drive system of a vehicle has a transfer clutch capable of varying torque transmitted therethrough from an engine to front wheels. This torque is controlled by a driving force distribution control unit in response to sensor signals of vehicle cornering behavior sensor such as a lateral acceleration sensor, vehicle speed sensor, transmission gear position sensor, and accelerator position sensor. The control unit determines a driving force distribution ratio between the front wheel driving force and the rear wheel driving force in accordance with the sensed lateral acceleration in such a manner that the share of the driving force apportioned to the front wheels is decreased with increase of the lateral acceleration.

Abstract: An electronic control for the automatic transmission of a motor vehicle receives input signal in digital, analog, and pulsed form from signal generating devices responsive to operating conditions in the apparatus, processes them in accordance with a stored program and provides output signals to operate various tranducers. The electronic control is embodied in a stack of customized circuit boards. Each board is connected to a control bus (for information exchange between boards) and to an I/O signal bus (for information exchange between the apparatus and the electronic control). A connector board is connected to an electric power supply, to the signal generating devices, to the transducers and to visual display devices. A CPU (central processing unit) board protects against data loss in low/off power conditions.

Abstract: A first clutch control is operated in response to an accelerator position signal so as to set a clutch from a disengaged state to a half engaged state. A second clutch control is provided for gradually engaging the clutch when a load signal from an engine load detecting is equal to or higher than a preset value, and for disengaging the clutch when the signal is higher than the preset value. After the second clutch control is operated when a difference between an engine speed and a clutch output shaft speed becomes equal to or lower than a predetermined value, the clutch is fully engaged by a third clutch control.

Abstract: The torque of a clutch disposed in parallel with a hydrodynamic power transmitting device provided between an engine and a transmission is gradually reduced upon disengaging the clutch when the torque of the engine is higher than a predetermined level. As a result, the instantaneous great drop in the output torque of the transmission at the time of the disengagement of the clutch is prevented to thereby improve the acceleration response of a vehicle.

Abstract: A control system for an electromagnetic clutch of a motor vehicle. Idling speed of an engine of the vehicle is increased for providing a fast idle state when a choke valve of the engine is closed. In the fast idle state, initial clutch current is reduced for engaging the clutch at depression of an accelerator pedal, and thereafter the clutch current increasing rate is quickly increased when the engine speed and throttle opening degree become large. When the accelerator pedal is quickly depressed, the reduced rate is increased in accordance with opening degree of a throttle valve for providing quick start of the vehicle.

Abstract: A vehicle includes an engine and an automatic transmission which has a fluid torque converter, a forward clutch, and a manual range setting valve. Idling control for providing anti creep control is performed by, during engine idling time while the manual range setting valve is set to a forward driving range and the vehicle is substantially stationary, reducing the engagement pressure of the forward clutch by reducing the actuating pressure provided to it. A rotational speed associated with the fluid torque converter is detected, and the actuating pressure provided to the forward clutch is controlled so that the rotational speed associated with the fluid torque converter does not drop below a certain rotational speed value. Thereby good anti creep control is provided. A system is also disclosed for performing the method.

Abstract: A system for controlling an electromagnetic clutch of an engine for a motor vehicle having a transmission. The system has various sensors such as an engine speed sensor, a vehicle speed sensor for detecting low vehicle speed, an accelerator pedal position sensor for detecting the acceleration of the engine, and a selector lever position sensor. The system has computing means for determining the clutch current at the beginning of the engagement of the electromagnetic clutch. The clutch current is determined such that a large clutch current is supplied at lower engine speed, and a small clutch current is supplied at higher engine speed at the beginning of the engagement of the clutch.

Abstract: The invention concerns a radial coupling with shoes, of a simple structure, eliable in operation, and which is engaged and disengaged without delay. The coupling comprises a body in which are provided several chambers. The chambers are connected by means of pipes with a source of pressurized fluid. The body is fixed on the axis of a winch. Movable pistons are disposed in each chamber and are loaded with return springs. Supports are disposed on each piston and each support carries a frictional covering.

Abstract: A system for controlling an electromagnetic clutch of an engine for a motor vehicle having a transmission. The system has various sensors such as an engine speed sensor, a vehicle speed sensor for detecting low vehicle speed, an accelerator pedal position sensor for detecting the acceleration of the engine, and a selector lever position sensor. The system has a computing unit for determining the clutch current at the beginning of engagement of the electromagnetic clutch. The rate of change of clutch current with respect to engine speed increases as the acceleration of engine speed increases.

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 creep preventive arrangement wherein a start-up pressure regulating valve discharges fluid from a servo chamber of a start-up clutch when a clutch piston assumes a predetermined creep preventive position, and a start-up detecting valve prohibits the fluid discharge from the servo chamber when a torque converter output revolution speed exceeds a predetermined value.

Abstract: A clutch slip control device for a lock-up torque converter has a clutch slip control valve and an operating range detecting valve which are operative to control a lock-up control pressure in a lock-up control chamber based upon a torque pressure representative of a torque transmitted by a turbine runner and upon a governor pressure and a throttle pressure representative of a vehicle speed and an engine load.

Abstract: A control system for controlling a fluid pressure to engage a start clutch of a vehicular automatic transmission has an actuator such as a solenoid valve for varying the fluid pressure supplied to the start clutch, a group of sensors for sensing one or more operating conditions of the vehicle and producing a start signal representing a start of the vehicle, and a controller such as a microcomputer for controlling the fluid pressure by sending a control signal to the actuator. In order to ensure a smooth start of the vehicle from a standing position in which the start clutch is disengaged, the controller varies the value of the control signal upon receipt of the start signal in such a manner that the control signal rises immediately, then falls rapidly to a low value, and finally increases gradually from the low value to an ultimate value.

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 clutch controlling apparatus for automatically carrying out the operation of a clutch device comprises a first output device responsive to the amount of operation of an accelerator pedal for producing a first operation control signal for carrying out the complete engaging operation of the clutch device in relation to the amount of operation of the accelerator pedal, and a second output device responsive to the amount of operation of the accelerator pedal for producing a second operation control signal for operating the clutch device in a semi-engaged state at an amount of semi-engagement related to the amount of operation of the accelerator pedal. Either the first or second operation control signal is selected by a selector in accordance with the amount and speed of operation of the accelerator pedal and the selected operation control signal is applied to the clutch device enabling the operating range of the accelerator pedal to be widened in a control mode according to the second operation control signal.

Abstract: A control apparatus is disclosed for a road vehicle, which contains a transmission control. The control apparatus includes, among other things, devices which recognize whether the vehicle is on the crest of a hill or in a valley, and whether the vehicle is travelling uphill or downhill over the crest of the hill or through a valley. For this purpose, the control apparatus includes a first devices which compares and calculates the difference between two stationary torques M.sub.stat calculated at different times which are necessary for nonaccelerating travel of the vehicle. In addition, the control apparatus contains a second devices which checks the mathematical sign of the difference .DELTA.M.sub.stat. Finally, the control apparatus contains a third devices which compares the stationary torque M.sub.stat with a specified value a.

Abstract: A four-wheel drive vehicle has an engine clutch for transmitting the output of an engine to a transmission, main drive wheels operatively connected to an output shaft of the transmission, auxiliary drive wheels, and a transfer clutch for transmitting the output of the transmission to the auxiliary drive wheels. A control system is provided with a detector for detecting a driving condition for reducing the torque capacity of the transfer clutch. The control system responds to a signal from the detector for gradually reducing the torque capacity of the transfer clutch.

Abstract: A method for controlling an AMT system (10) is provided including sensing clutch (16) reengagement after a transmission (12) gear change operation and providing closed loop control of both the clutch operator (30) and the fuel control (26) under such conditions.

Abstract: A four-wheel drive vehicle has an engine clutch for transmitting the output of an engine to a transmission, main drive wheels operatively connected to an output shaft of the transmission, auxiliary drive wheels, and a transfer clutch for transmitting the output of the transmission to the auxiliary drive wheels. A control system is provided with a steering angle sensor producing a steering signal dependent on steering angle of the vehicle, a throttle position sensor producing a signal dependent on throttle position, and a vehicle speed sensor producing a vehicle speed signal. A control unit is provided to respond to the steering signal, the throttle position signal and the vehicle speed signal for controlling the torque capacity of the transfer clutch so as to reduce the torque capacity with increase of the steering angle and with decrease of the vehicle speed and degree of throttle position opening.

Abstract: A hydraulically-actuated starting clutch adapted for a continuously variable transmission which is located at the output of the transmission to couple the vehicle wheels to the engine upon a signal from the throttle induced system oil pressure. The clutch includes a cover connected to the drive shaft through a hub forming a pressure chamber behind a piston, a Belleville spring acted upon by a pressure disc extending between the spring and the piston and urging a pressure plate against the clutch plate and an end plate secured in the cover, and retractor fingers on said pressure disc engaging said pressure plate. A cooling oil impeller is positioned between the end plate and a clutch plate hub and operatively connected to the end plate, and the clutch plate is operatively connected to a sleeve shaft to drive the differential for the vehicle wheels.

Abstract: The net engagement pressure of a torque converter clutch having a negative slope capacity vs. slip characteristic is controlled to stably regulate the clutch slip, and thereby isolate engine torque perturbations from the vehicle driveline. The pressure is scheduled with a proportional term responsive to transient slip speed deviations and an integral term responsive to steady state slip speed deviations. Feed forward terms responsive to the throttle changes which force steady state slip speed deviations act to increase the speed of response of the integral term.

Abstract: A four-wheel drive vehicle has an main clutch for transmitting the output of an engine to a transmission, main drive wheels operatively connected to an output shaft of the transmission, auxiliary drive wheels, and a transfer clutch for transmitting the output of the transmission to the auxiliary drive wheels. A control system is provided with a detector for detecting whether the main clutch is in partial engagement state or entire engagement state and for producing a clutch condition signal representing a clutch condition. The control system responds to the clutch condition signal for controlling torque capacity of the transfer clutch so as to slip the transfer clutch.

Abstract: In a transmission comprising a plurality of freely rotatable gears on a change-speed shaft, shift keys slidably disposed within the shaft are supported by a shift collar pivotally but non-slidably by an engagement of the keys with the inner circumference of shift collar. The shift keys are biased to pivot for a selective gear-coupling operation by compression leaf springs disposed between an end face of the shift collar and base end projections of the shift keys.The springs arranged outside the shaft will not require a particular design of the keys and contribute to prolong the life of shift keys. The support structure for shift keys by the shift collar as well as the arrangement of key-biasing springs will secure a compactness of the transmission.

Abstract: A lock-up clutch control device for an automatic transmission having a torque converter with a lock-up clutch and a speed changing gear mechanism including a sub-transmission unit and a main transmission unit. The device has a lock-up operation device for producing a control signal when the sub-transmission unit is in the higher speed mode or when the main transmission unit selects 2nd or a higher speed gear. The control signal is delivered to a lock-up relay valve which operates effectively while it receives the control signal. Therefore, the torque converter can be locked up at 2nd or higher speeds of the automatic transmission which, because of various combinations of the states of the sub-transmission and main transmission units, outputs multiple speed.

Abstract: A controller for the hydraulic clutch of two speed auxiliary transmission connected in series with the main transmission and engine of a vehicle wherein the hydraulic clutch is applied for the higher speed drive and released for the lower speed drive which is through a one-way clutch that overruns in the higher speed drive operation. The controller is responsive to engine throttle opening to apply the hydraulic clutch for throttle openings below a predetermined amount to allow braking of the vehicle by the engine during deceleration rather than coasting by the overrunning of the one-way clutch.

Abstract: The invention relates to a control apparatus for a clutch disc assembly drivingly associated with an engine. Protection from engine stall resulting for inertia loads downstream of the engage clutch disc assembly instantaneously exceeding available engine torque involves sophisticated brakes, intricate sequence controls, and complicated internal clutch control valving. The present apparatus includes a control valve for controllably directing fluid pressure to the clutch disc assembly from a source of fluid pressure. A valve member reciprocally disposed in the control valve is continually urged in a first axial direction. A speed sensor associated with an input member driven by the engine urges the valve member in a direction opposite the first axial direction in response to a decrease in the rotational speed of the input member to a preselected angular velocity slipping the clutch disc assembly.

Abstract: A vehicle automatic transmission including a torque converter having a lock up clutch. A lock up control circuit is provided and has a memory including a first lock up control line for controlling the engagement and release of the lock up clutch when the torque converter turbine speed is close to the pump impeller speed, and a second lock up control line which is drawn along a line wherein the engine output torque is substantially zero so that the lock up clutch is released at a given engine load when the turbine speed is decreased beyond the first lock up control line, or when the turbine speed is increased beyond the second lock up control line.

Abstract: Herein disclosed is a method of controlling an automatic clutch when starting to move a vehicle such as an automobile having an automatic transmission. The maximum accelerating r.p.m. of an engine at the start is detected and stored so that a clutch actuator is kept deenergized to leave the clutch released, while the engine r.p.m. detected is lower than the maximum value stored, but is energized again to apply the clutch when the engine r.p.m. exceeds the maximum value. More specifically, the running state of the vehicle is detected to determine the operating speed of the clutch actuator, and the automatic clutch is applied at the operating speed deterined. The engine r.p.m., once the vehicle is moving is detected and compared with the maximum accelerating engine r.p.m. Then, the operating speed of the clutch actuator is dropped to zero to interrupt engagement of the clutch while the engine r.p.m. detected is smaller than the maximum engine r.p.m. Engagement of the clutch is restored when the engine r.p.m.

Abstract: A system for controlling an infinitely variable transmission is provided with a vehicle speed sensor for sensing vehicle speed and for producing a signal when the vehicle speed exceeds a predetermined value, a neutral range sensor of the transmission, a drive range sensor, and an accelerator pedal release sensor. The system further has an actuator for cutting off fuel. When the vehicle coasts under conditions of the drive range, accelerator pedal release, and at a higher vehicle speed than the predetermined value, fuel is cut off. When the neutral range is selected under the fuel cut off state, the clutch is engaged with a delay.

Abstract: A system for controlling an electromagnetic clutch for an infinitely variable belt-drive transmission, which is provided with an accelerator pedal switch for producing an output signal at release of an accelerator pedal of a vehicle, and a vehicle speed detector for producing an output signal at a low vehicle speed. The system is arranged to produce a small drag current signal in dependency on the accelerator pedal release signal and the low vehicle speed signal, so that a small drag clutch current flows in a coil of the electromagnetic clutch.

Abstract: A clutch control system includes an electronic control apparatus for controlling a clutch based on clutch control data stored through a learning process. The clutch control system has a sensor for measuring the temperature of lubricating oil in a gear transmission, a memory for storing a corrective clutch control value commensurate with the temperature of the lubricating oil, and an electronic control apparatus for correcting a learned value used to control the clutch with the corrective clutch control value obtained on the basis of the measured temperature of the lubricating oil.

Abstract: The transmission of torsional vibrations from a rotating driving shaft, at the output of an internal combustion engine, to a driven shaft, at the input of a manual transmission, are reduced or eliminated by employing a normally-engaged, oil-cooled wet clutch to interconnect the two shafts, the clutch being controlled to introduce a desired amount of slippage. Slipping the wet clutch to a relatively small extent allows the necessary torque to be transmitted, but any torque fluctuations in the driving shaft will be effectively absorbed and prevented from causing torsional vibrations in the drivetrain.

Abstract: A system for controlling the clutch current of an electromagnetic clutch for a vehicle which has a transmission and a gear shift lever for changing change-speed gears in the transmission. A shift lever switch is operated when the shift lever is operated passing through a neutral position. A logic gate circuit is provided to respond to a signal of the shift lever switch for cutting off the clutch current. A timer is responsive to the disappearance of the signal upon engagement of the gears for producing an output with a delay, for opening the logic gate circuit, whereby the cluch remains disengaged for a predetermined period after engagement of the gears.

Abstract: A system for controlling an electromagnetic clutch has a vehicle speed sensor and an accelerator pedal switch. The clutch current is cut off at a low speed of a vehicle in response to a signal of the accelerator pedal switch at the release of an accelerator pedal. The system is arranged to supply a small drag current to the coil of the clutch in a very low vehicle speed range including stopping of the vehicle.

Abstract: A system for controlling an electromagnetic clutch has a reference valve generator which produces clutch-engaging and clutch-disengaging engine speed signals in a low vehicle speed range. Engine speed is compared with the engine speed signals by a comparator. The clutch is engaged at a higher engine speed than a clutch disengaging speed and disengaged at a lower engine speed than a clutch engaging speed in accordance with the result of the comparison.

Abstract: An automatic clutch control system and method for controlling a clutch for an automatic transmission when a clutch stroke sensor fails. The apparatus includes a clutch actuator for controlling a clutch stroke, a plurality of solenoid valves for controlling the clutch actuator, a clutch stroke sensor for measuring the clutch stroke, a control unit for feeding back a stroke signal detected by the clutch stroke sensor when requests for clutch engagement or disengagement are received and for controlling the solenoid valves so as to obtain a clutch moving speed defined by an engine rotational speed and other driving conditions. The control unit further includes a clutch engagement control section and a clutch disengagement control section for controlling solenoid valves for operating the clutch independently of the stroke signal when the stroke sensor fails.

Abstract: A system for controlling clutch torque for a vehicle which has a transmission and an electromagnetic clutch provided between an engine and the transmission, the clutch current being increasing with increase of engine speed. The system comprises an engine speed sensor for sensing the speed of the engine and for producing an engine speed signal in proportion to the engine speed, and an acceleration detecting switch for producing an acceleration signal.A vehicle speed detecting unit is provided for sensing the vehicle speed and for producing an output when the vehicle speed reaches a predetermined value at a low engine speed.A clutch current control unit is provided to respond to the output of the vehicle speed detecting unit and to the acceleration signal for increasing the clutch current along at an inclination up to a rated current.

Abstract: In a continuously variable transmission apparatus for a vehicle having a slip type clutch disposed between a drive shaft of an engine and an input shaft of a continuously variable transmission mechanism, a torque detecting device to detect torque of the engine, an engine speed detecting device to detect rotational speed of the engine, an output shaft speed detecting device to detect rotational speed of an output shaft of the slip type clutch, a vehicle speed detecting device to detect running speed of the vehicle, and an electronic control device to control the continuously variable transmission mechanism and the slip type clutch according to signals from the detecting devices are provided. The slip type clutch control device is controlled to give a reference amount of slip determined according to driving condition of the vehicle, and speed ratio of the continuously variable transmission mechanism is controlled to a value determined primarily on the basis of control signal of the slip type clutch.

Abstract: An automatic transmission system has a controllor for controlling the slip rate of a clutch in accordance with the amount of depression of an accelerator pedal instead of controlling the ON/OFF condition of the clutch by a control signal when it is discriminated that the gear change position of a transmission and the amount of depression of the accelerator pedal are in the predetermined states. In a predetermined condition, the slip rate of the clutch is adjusted in accordance with the amount of depression of the accelerator pedal so as to put the clutch in a semi-engaged condition, thereby enabling the speed of the vehicle to be controlled within a very low speed range simply by operation of the accelerator pedal.

Abstract: A microprocessor controlled drive train having an engine-connected variable ratio speed transmission and a load-connected range gear transmission connected by a mid-mounted clutch disposed therebetween has an automatic clutch control mode of operation, with the clutch disengaged and the range transmission in gear to complete a shift, wherein the speeds of the clutch sides are synchronized before engagement by appropriately varying the ratio of the speed transmission, thereby eliminating shift shock. This automatic clutch control mode is preferably employed in combination with operating modes which control both the speed transmission ratio and engine throttle to maintain fuel efficient operation.

Abstract: A system for controlling the clutch torque of an electromagnetic clutch for a vehicle, having an accelerator pedal switch for producing an output signal when an accelerator pedal of the vehicle is released. A clutch current circuit including a transistor is provided for controlling the clutch current passing through a coil of the electromagnetic clutch. A logic gate circuit is provided to be responsive to the output signal of the accelerator pedal switch for controlling the transistor so as to decrease the clutch current to a low value approximating zero for a moment and thereafter to gradually increase the current to a predetermined value. The second circuit comprises a logic gate circuit and a pulse train generating circuit responsive to the output signal of the accelerator switch for producing a pulse train controlled by the logic gate circuit, and the duty ratio of the pulse train gradually varies so as to gradually increase the clutch current.

Abstract: In a vehicle clutch control apparatus having an actuator for operating a friction clutch and a controller for controlling the actuator, whereby a first data representing a semi-engaging zone is obtained by the controller just after the engine is started and the vehicle is driven to move, the apparatus has a data generator for producing a second data relating to the magnitude of the load of the vehicle and a unit for correcting the first data in accordance with the second data. As a result, data representing the actual semi-engaging zone of the clutch depending upon the load conditions of the vehicle at that time can be obtained, so that it becomes possible to realize an appropriate semi-engaging operation even when the load of the vehicle has changed.

Abstract: In the control of the slip in a slip clutch device for joining and separating an input shaft and an output shaft, the improvement comprises detecting a slip in the clutch, calculating a time change in the said slip and calculating a slip deviation between a preset target slip and the said slip, and feedback-controlling the engaging force of the clutch in proportion to the quantity of the time change in the said slip, obtained from these calculations, and the slip deviation so that the slip in the clutch is caused to get near to the target slip.According to the slip clutch device control method of this invention, the hunting in slip can be prevented from being caused even when the .mu.-v characteristics of a clutch facing is worsened, and a shock applied upon the clutch at the start of its operation can be reduced in a large extent.

Abstract: A control system for automatic clutch is disclosed wherein a clutch torque is detected and the engagement of the clutch is controlled such that the detected clutch torque is brought into agreement with a creep clutch torque when a vehicle is under a pre-start-up operating condition and into agreement with a target clutch torque determined for engine operating condition when the vehicle is not under the pre-start-up operating condition.

Abstract: The control device comprises an electric motor-gearbox unit (2) acting on the thrust bearing (16) of a clutch (1) and a switching device (3) comprising four transistors adapted to apply the voltage from the battery (30) with either polarity to the motor (20) of the motor-gearbox unit (2) according to whether the output of "AND" gates (41 and 42) is at 1. This occurs, when end of travel switches (28 and 29) are closed, when positive pulses appear at the output (40c) of the microprocessor (40) and according to whether the output (40d) is at "0" or "1". The microprocessor produces pulses of defined duration at its output (40c) with a recurrence frequency which is a direct function of the frequency produced by the sensor (50) responsive to the rotation speed of the motor when above a threshold higher than the idling speed, in the clutch engagement phase, and which is such in the clutch release phase that the pulses are adjacent.

Abstract: A direct-coupling control system for a fluid gear in an automatic vehicular transmission, having a fluid gear provided with input and output members; a direct-coupling mechanism capable of connecting the input and output members of the fluid gear mechanically and directly by a locking force which is determined on the basis of a function of a difference between a working pressure and an internal pressure in the fluid gear; and a control valves provided between a pressure supply source and the direct-coupling mechanism and adapted to control the working pressure. The direct-coupling control system includes a pressure retainer valve for controlling the internal pressure in the fluid gear so as to reduce the same in accordance with an increase in a vehicle speed or an engine output.

Abstract: A clutch control system for a continuously variable transmission includes a mode determination system which samples input signals including position of the neutral-drive selector, driver demand, engine speed, vehicle speed, and clutch input speed. From these signals the operating mode is determined and the clutch control system operating mode is set. In starting the vehicle, a minor pressure feedback loop and a major engine speed feedback loop are used. When the clutch is locked up, these control loops are not employed in regulating the vehicle operation.

Abstract: An improved automatic clutch control system for controlling a vehicle master clutch (14) drivingly interposed a throttle controlled engine (12) and a change gear transmission (10) in an automatic mechanical transmission system (AMT) is provided. The control provides at least one modulated clutch engagement mode of operation wherein the clutch is moved rapidly from the fully disengaged to the incipient engagement position (A), and is then moved in a modulated manner, according to logic rules, to the fully engaged position. A monitored clutch actuator (22) parameter is compared to a reference value (C) to determine the expected point of incipient engagement of the clutch. The reference value is periodically updated, to compensate for wear and the like, by monitoring the sensed or calculated value of the monitored clutch actuator parameter at the time a monitored system parameter (108, 110) responds in a manner predictable for the instant of incipient engagement of the clutch.

Abstract: A propulsion system for a vehicle provides for a drive shaft to be powered by an electric motor or an internal combustion engine, the motor being permanently coupled to the drive shaft and the engine engageable with the shaft by a clutch. Engine speed is matched with that of the drive shaft before engagement of the clutch by electrically loading the engine, preferably by coupling a generator to the engine and varying the generator field current. The clutch is automatically engaged when the speeds are equal.