Abstract: A method for rocking a motor vehicle free. The vehicle has a drive-train with an automatic drive torque adjusting element, which transmits torque to a wheel, and a rotational speed and direction sensor system for detecting movement of the vehicle such that when the accelerator pedal is biased to a position different from its non-actuated position a desired drive torque can be produced. The torque adjusting element can be controlled based on the accelerator pedal position in relation to the drive torque that can be produced by the driver, and, in a rocking-free process, alternating deflection and release of the accelerator pedal causes the drive torque to fluctuate. With the rotational speed and direction sensor system, the drive torque adjusting element is controlled to suppress drive torque transmission if the travel direction of a current unpowered vehicle movement is not the same as a forthcoming power-driven vehicle movement.

Abstract: A switchable coupling with a coupling system between a driving element and an output element is provided. The switchable coupling includes an actuator, an elastic actuating element and a switching element movable between starting, central and end positions. In the central position the switchable coupling has a different state (open or closed) than in the starting position. The switchable coupling further includes a bolt constrained between first and second bolt stops. Axial movement of the switching element causes operative surfaces connected to the switching element or the bolt to engage with elements on other of the switching element and the bolt, such that the bolt rotates relative to the switching element. The bolt alternately moves relative to the switching element into a first relative position blocking switching element movement in the central position, and into a second relative position permitting movement of the switching element toward the starting position.

Abstract: A clutch arrangement for connecting two components, which can rotate relative to one another, of a motor vehicle drive train, in particular for connecting two shafts of a transmission or a shaft to an idler gear rotatably mounted on the shaft. The clutch arrangement has a clutch and an actuator arrangement. The clutch is opened in a first actuator position of an actuator section of the actuator arrangement. The clutch arrangement has a locking device for locking the actuator section in a locked position to keep the clutch closed. The locking device has a slotted-link guide with a first guide section and a second guide section for the actuator section, wherein the locked position can be reached from the first actuator position via the first guide section, and wherein the first actuator position can be reached from the locked position via the second guide section.

Abstract: The clutch assembly includes a controlling lever, a push bar, a locking shaft, a guiding sleeve, a driving sleeve, and a restoring spring member. The locking shaft has several locking protrusions and several guiding protrusions formed thereon. The push bar is driven by the control lever to push the locking shaft axially move along a rotation axis, and the guiding protrusions therefore engage with the driving sleeve. The driving sleeve is driven to rotate for making the locking protrusions aligned with the locking grooves. The restoring spring member bounds and pushes the locking shaft to an engaging position while the locking protrusions are received in the locking grooves. Thus, the clutch assembly is easily switched from a disengagement status to an engagement status.

Abstract: Articulation system comprising first and second articulations, each comprising two fittings which are pivotable relative to one another and a locking mechanism which comprises a control member which is mobile between a locked position and an unlocked position, the control members each being urged in a resilient manner into the locked position by a return member, a manoeuvring member which is mobile in rotation between a neutral position, a position of misuse and an actuating position, in order to unlock the control members when said manoeuvring member is displaced in a first direction, said manoeuvring member being returned from the position of misuse and the actuating position into the neutral position by a dual-action return device.

Abstract: A bi-directional clutch assembly of the present invention is provided that comprises an inner race, an outer race, and an engagement mechanism disposed between said inner race and said outer race. The engagement mechanism is operable to move between a disengaged position wherein the inner and outer races may freely rotate relative to one another and an engaged position wherein the inner and outer races are locked so as to translate torque therebetween. The present invention also includes at least one actuator that is operatively connected to the engagement mechanism and responsive to a first momentary control force to selectively move the engagement mechanism to the engaged position and to hold the engagement mechanism in the engaged position after the first control force has been terminated.

Abstract: A lift lock for blind is disclosed to include a shaft pivoted to a headrail of a blind for synchronous rotation with a lift rod of the blind. The shaft has a constraint device. A switching mechanism is mounted inside the headrail of the blind and has a sliding member movable between a locking position and an unlocking position. The sliding member has an engagement device, which engages the constraint device to stop the shaft from rotary motion when the sliding member moved to the locking position, or is disengaged from the constraint device for enabling the shaft to be rotated with the lift rod when the sliding member moved to the unlocking position. And, a control mechanism has a pull rod for pulling by the user to switch the switching mechanism between the locking position and the unlocking position.

Abstract: The present invention is directed to a power transfer system for a four-wheel drive vehicle equipped with a torque transfer coupling which includes a clutch pack and a ball-screw actuator. The ball-screw actuator functions to axially translates an apply plate to operatively engage the clutch pack and vary the frictional engagement. This arrangement yields numerous operational advantages over the prior art including, but not limited to, establishing a direct drive between the motor output shaft and the apply plate, concentric mounting of the actuator elements with the motor output shaft, and a simplified mechanical arrangement that reduces the number of frictional elements increasing operational efficiency and decreasing motor requirements.

Abstract: A device for actuating a system such as a clutch or a gearbox associated with an engine, particularly a motor vehicle engine, and comprising control element (26-31) and an actuation member (38). According to the invention, the device furthermore includes:a first shaft (4) rotationally driven by the engine;a second shaft (6) integral with the actuation member;coupling member (10, 13, 15, 16, 33) for coupling the second shaft to the first shaft under the action of the control element;a member (16, 32, 33; 48, 53) for uncoupling the second shaft from the first shaft after the second shaft has rotated through a predetermined angle; anda return spring (35) for returning the second shaft to its initial position after it has been uncoupled from the first shaft.

Abstract: A pulse actuated interlock mechanism for a vehicle that couples and uncouples a drive member and a driven member. A clutch member is slidably movable to couple or uncouple the drive and driven members. A latchable piston assembly in combination with a return spring is utilized to move the clutch member. A force of short duration of a first magnitude is applied to latch the piston assembly which permits the return spring to move the clutch member to uncouple the drive and driven members. A force of a short duration of a second magnitude which is greater than the first force is applied to unlatch the piston assembly. A biasing member of the piston assembly moves the clutch member to couple the drive and driven members when the piston assembly is in the unlatched condition. The clutch member, return spring and piston assembly are installed in a modular housing.

Abstract: An impulse actuated clutch with latch for a drive line of a vehicle. The impulse actuated clutch has a coupling member that is permanently engaged with one of a driven member and a driving member. The coupling member is movable in a first direction to engage one of the driven and driving members and is movable in a second direction to engage both the driven and driving members. The coupling member is biased to move in the first direction by a return spring. The coupling member is moved in the second direction by a first pulse of air pressure applied to a piston assembly connected to the coupling member. Formations formed on a primary piston of the piston assembly and the driven member cooperatively latch the piston in the second position to the maintain the coupling member in engagement with both the driven and driving members upon release of the first pulse of air pressure.

Abstract: A device for engaging and releasing of wheels by fluid control, applied in vehicles equipped with more than one drive shaft, and with hydraulic, pneumatic or vacuum system responsible for its operation, with such device being mounted within a housing (1) fixed to the wheel hub (2) of the vehicle, within which there is the engaging hub (4) with a serrated portion (4') coinciding with the inner teeth (6') of the engaging element, surrounded by a spring (7); in front of the engaging element (6) there is a cam (8), the inner face of which has a channel (9) in which the studs (10) provided in the outer edge of the cam following part (11) move, with the cam following part being kept in contact with the driving element (12) of the device due to the action of an engaging spring (13) with the cam (8) being mounted directly on the housing (1) or being surrounding the guiding ring (14), provided with horizontal grooves ( 14').

Abstract: In a method for correcting clutch data used for controlling the engaging/disengaging operation of a friction type clutch, meet position data is updated only when the clutch temperature is less than a prescribed value and the clutch data is corrected by the use of the updated meet position data, whereby learned meet position data affected by clutch temperature increase is prevented from being used for the correction of the clutch data. As a result, clutch data is properly corrected regardless of change in the clutch temperature.

Abstract: An apparatus for operating a lockup clutch to provide a controlled degree of slip between the impeller and the turbine in an automatic transmission. A gear ratio is calculated from a relationship specifying the gear ratio as a function of selected gear change mode and time elapsed after the selected gear change mode starts. The calculated gear ratio is used, along with the transmission output shaft speed to calculate a speed of rotation of the turbine. The lockup clutch is operated in a slip lockup mode to bring a difference between the engine and turbine speeds to a predetermined value. Engine speed changes are monitored to measure a time interval required for the gear change of the selected mode. The relationship is modified to correct the gear ratio stored for the selected gear change mode based upon the measured time interval.

Abstract: A system for controlling the selection of the operative ratio of a vehicle powershift transmission driven from an engine via a main clutch. The system includes a clutch status sensor for sensing engaged and disengaged conditions of the main clutch. A selector is provided for selecting the operative ratio of the transmission. Also, a control circuit is provided which includes a ratio-change modulating function which, when the main clutch is engaged and a change to a non-adjacent ratio is selected, invokes a serial routine which ensures that each intermediate ratio between the current ratio and the selected ratio is engaged for a moment to ensure a smooth substantially jerk-free progression between the current ratio and the selected ratio. When the main clutch is disengaged and a change to a non-adjacent ratio is selected, the control circuit invokes a direct routine which permits changes from a current ratio to a non-adjacent selected ratio without engagement of any intermediate ratio.

Abstract: A power downshift control method/system strategy (FIG. 6), based upon sensed torque converter slip (TC slip) is provided for an automated mechanical transmission system (12) including an engine (16), a mechanical transmission (14) and a torque converter (20) drivingly interposed the engine and transmission. At the beginning of a power downshift, the target gear is derived from the TC.sub.-- slip, vehicle deceleration, current gear and operator throttle demand. These four vehicle conditions are parameters of a four dimensional matrix such that increasing values of each parameter promote a greater potential for skip power downshifting.

Abstract: A control system for a vehicle powershift transmission includes a set of electrical connectors which in a normal mode, permit electrical power to be transmitted to microprocessor-controlled valve drivers for the transmission clutch control valves. These connectors may be swapped, in a limp-home mode, to permit power to be transmitted directly to the transmission clutch control valves. In both modes, a start-in-gear protection circuit including a pair of relays and switches coupled to the shift lever prevents the vehicle from being started up with a gear engaged. In the limp-home mode, a limp-home relay and a clutch disengaged switch prevents gear engagement until the operator has depressed and then released the clutch pedal, and the clutch pedal may be operated to modulate and control gear engagement.

Abstract: The hydraulically operated brake and clutch elements (controlled by proportional control valves) of a vehicle powershift transmission have fill pressures which are calibrated by a method wherein the output shaft of the transmission is disconnected from the vehicle drive shaft so that the transmission output shaft is free to rotate and certain ones of the plurality of the control elements other than the control element being calibrated are fully pressurized in order to prevent rotation of a part of the control element being calibrated. The engine is run at a predetermined speed and the pressure applied to the control element being calibrated is gradually increased while engine speed is monitored. When the monitored engine speed changes by predetermined amount, a value is saved corresponding to the calibration pressure. The transmission is automatically shifted to neutral if vehicle motion is sensed.

Abstract: When a drive range of a transmission is selected from a neutral range at a high engine racing speed, a racing start signal is produced. In response to the racing start signal, the electromagnetic clutch is engaged at a higher engaging rate than an ordinary engaging speed.

Abstract: An accelerator pedal device comprises a pedal lever having a pivot shaft which is pivotally supported by a fixed support bracket. The pedal lever is biased in such a direction that an upper part of the pedal lever approaches a fixed stopper member. A first auxiliary lever is pivotally supported by the pivot shaft and has a first upper portion located between the stopper member and the upper part of the pedal lever. A second auxiliary lever is pivotally supported by the pivot shaft and has a second upper portion located between the first upper portion and the upper part of the pedal lever. A first lost-motion mechanism is provided between the pedal lever and the second auxiliary lever, and a second lost-motion mechanism is provided between the second and first auxiliary levers.

Abstract: A transmission control system with gear shift failure detection includes a transmission (1), each gear of which is equipped with a synchromesh mechanism (1e); an actuator unit (2) consisting of a shift actuator (2a) for making a gear shift in a shift direction and a select actuator (2b) for making a gear shift in a select direction; a control unit (4) for calculating a target position signal (M) from an amount of pressdown of an accelerator pedal, a vehicle speed, and a set position of a gear selector to control not only the actuator unit so that a gear is set within a target range but also a clutch so that connection or disconnection is made according to an operation of the transmission; a position detector (2f, 2g) provided in each of the shift and select actuators for detecting a position of a piston rod (2c, 2d); a servo cylinder (2a, 2b) in response to a signal from the position detector to position the piston rod at a given position of each gear; a speed detector (4a) in response to a signal from the po

Abstract: An IC engine is connected via a clutch with a change-speed transmission. A sensor responding to a gear selection informs the electronic control circuitry in which gear the vehicle is traveling. The rotary part of a tachometer is provided at the output of the transmission and is in cooperation with the sensor part of the tachometer, which feeds a signal to the electronic control circuitry. A universal joint shaft runs from the output of the transmission to the axle transmission, which is connected via the axles to the drive wheels. The rotary tachometer elements, connected with the drive wheels, are in cooperation with the tachometer sensors, whose output signals are supplied to the electronic control circuitry and compared therein with a calibration value. Such comparison determines the optimum clutch engagement time for the respective travel and loading condition of the vehicle.

Abstract: In a system for controlling a clutch for vehicle having an automatic gear-transmission control system, the clutch is controlled so as to be disengaged when a gear of the transmission is in a prescribed low-speed gear position at which strong engine braking power can be expected and fuel-powered operation of an engine for powering the vehicle has stopped during the running of the vehicle, whereby it can be prevented to apply sudden engine braking power to the vehicle.

Abstract: A fluid coupling for an automatic transmission includes an input element, an output element and a lockup clutch and is connected to a transmission mechanism. The lockup clutch can engage and disengage to operatively connect and disconnect the input element and the output element with and from each other. Further the lockup clutch can engage in slipping engagement to connect the input element and the output element in such a way as to allow the input element and the output element to rotate relative to each other to some extent. A control system causes the lockup clutch to engage in slipping engagement with a substantially fixed engaging force when the transmission mechanism upshifts while the lockup clutch is in slipping engagement, and to disengage when the transmission mechanism downshifts while the lockup clutch is in slipping engagement.

Abstract: A method of controlling a speed changing operation wherein the method is preferably employable for a caterpillar drive type construction machine including a direct transmission is disclosed. When a shift-up speed changing operation is to be performed, the method is practiced by way of the steps, i.e.

Abstract: A continuously variable belt drive transmission has a torque converter with a lockup clutch. The lockup clutch is engaged in accordance with driving conditions of the torque converter. Quantity of downshifting the transmission is decided in dependency on changing rate of speed of an input member of the transmission so that the speed of the input member coincides with speed of the engine. The transmission is downshifted by the downshift quantity and the lockup clutch is engaged so as to change the engine speed at a substantially constant rate.

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 motor vehicle power line comprises a combustion engine (8), a gearbox (10) and an electronically controlled clutch (20). The engine throttle (84) is actuated by an electric motor (92) controlled by the electronic control (48) usually in response to throttle demand signals. A manual move of the gear shift level (16) causes the clutch (20) automatically to disengage. When a new gear is engaged the clutch (20) is automatically re-engaged. When the gear change is an up-change the clutch (20) is automatically disengaged to lower (102) its torque transmitting capacity (C) from a maximum (C1) to zero. As the gear change progresses the new gear starts to be engaged causing the speed (B) of the gearbox input shaft (14) and clutch driven plate (32) to drop (110) to (Sn). While this is happening control (48) takes full control of the throttle and closes it. The disengaged clutch and closed throttle causes the engine speed (A) to decelerate (114).

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: In a method for correcting clutch data used for controlling the engaging/disengaging operation of a friction type vehicle clutch, the meet position data among the clutch data is updated by a learning operation at each operation of a predetermined operation member of the vehicle, and the updated meet position data is corrected in accordance with the engine speed during the actual operation of the clutch, each time the vehicle is driven off, whereby appropriate correction of the clutch data can be carried out at suitable time intervals.

Abstract: An automatic transmission with an engine rpm sensor fault detector includes a starter switch (18); a clutch (6) for transmitting an output of an engine (8); a clutch control unit for controlling engagement of the clutch; a transmission (1); an engine rpm sensor (9); a an input shaft sensor (5a); a gear position sensor (40a) for detecting a gear position of the transmission; a control unit (4) for controlling the clutch control unit based on outputs of the respective detectors and enables the starter switch to operate when the transmission is in a neutral position. The control unit includes a starter switch detector (40b) for determining whether the starter switch is on and a fault determination unit (40c) for determining whether the first detector is faulty.

Abstract: A coast-sync-coast control method for clutch-to-clutch shifting in which an engine control is employed to synchronize the engine speed with the transmission input speed at a point where the input speed would otherwise exceed the engine speed. The shift is referred to as a coast-sync-coast shift since (1) it is initiated at a coast condition where the input speed is higher than the engine speed, (2) it is completed at a synchronous condition where the speed differential across the on-coming clutch is at or near zero, and (3) a coast condition recurs immediately after the shift.

Abstract: A shifting system used in combination with a motor-vehicle engine having an output connected via a clutch to the input of a multiratio transmission in turn having an output connected to a load comprises respective sensors for detecting the speeds of the motor output, transmission input, and transmission output and for generating outputs corresponding thereto, and respective clutch and transmission sensors for detecting the settings of the clutch and transmission and generating outputs corresponding thereto. A shifter element can move between an actuated position and an unactuated position. A double-display has a current-setting part and an ideal-setting part and is connected to a controller that is also connected to the sensors. This controller displays on the current-setting part the current setting of the transmission and on the ideal-setting part a setting calculated to be ideal based at least on engine characteristics and transmission output speed.

Abstract: A friction clutch system is disclosed to couple a drive shaft and a driven shaft together by hydraulically urging clutch surfaces together. A pump for pressurizing the hydraulic system is mechanically coupled between the drive and driven shafts to rotate at speeds increasing with the difference in their respective speeds.

Abstract: The present invention relates to a drive train of a wheeled vehicle having an engine and at least one driving wheel, the drive train essentially including a first clutch connected to the engine for receiving driving force therefrom and for outputting the driving force in a variable manner according to driver operation driver; a transmission connected to the first clutch effective for receiving the driving force from the engine as varied by the driving transmitting it a varying rotational speed; and a second clutch connected to the transmission for receiving such driving force from the transmission and transmitting it to the driving wheel by automatically varying the transfer ratio between the transmission and the driving wheel according to the rotational frequency of the transmission output.

Abstract: In an automatic transmission system for a vehicle having a gear transmission and a clutch which are electronically controlled by a control unit, the system includes a discrimination unit for discriminating whether or not the vehicle is running with the gear transmission shifted to its neutral position and a determining unit for determining a target gear position to which the gear transmission is to be shifted in the case where the vehicle is running without fuel-combustion in the engine. The control unit is caused to control the gear transmission to shift to the target gear position and the clutch to engage in response to the discrimination unit when an ignition switch is turned to its OFF position in the case where the vehicle is running with the gear transmission shifted to the neutral position, whereby the rotational torque of wheels can be transmitted through the automatic transmission system to the engine.

Abstract: The engine output torque of a motor vehicle is a function of the extent to which the throttle valve is open, the further the valve is open, the greater the throttle angle and the greater the output torque. Microprocessor based clutch control is provided to measure the throttle angle, determine the output torque, and automatically engage and disengage the clutch with respect to time. The clutch control also allows manual gear operation and clutch slip control.

Abstract: A control system for a motor vehicle of the type including a clutch and an manual gearbox. The control system includes an electric power module for shifting the gearbox, an electric power clutch assembly for engaging and disengaging the clutch, an electric throttle control assembly, and a control module arranged to control the gearbox power module, the clutch power module, the clutch power assembly, and the throttle control assembly in response to receipt of an operator instigated shift command signal. The control module initially operates to disable the throttle control system and disengage the clutch, thereafter operates to energize the gearbox power module in a sense to shift the gearbox to the selected position, and thereafter operates to reengage the clutch and restore operator control of the throttle control assembly.

Abstract: A system for disengaging an electromagnetic clutch upon selection of an opposite driving range of an automatic transmission. When a forward driving range is selected during rearward driving or a rearward driving range is selected during forward driving, a loading shift signal is produced. In response to the loading shift signal at a vehicle speed higher than a clutch engaging vehicle speed, the electromagnetic clutch is disengaged in order to prevent the engine from stalling.

Abstract: A control apparatus is provided which controls a motor, clutch and drive gear arrangement. The device consists of a movable control lever assembly which moves from a neutral position into at least one other operating position. The control apparatus includes a switching device that is operated as a two-part activating member. The activating member is mounted in a guide arrangement which remains in a fixed position in relationship to such control lever assembly. The activating member can be moved from a neutral position of such control lever assembly into a second position in which the activating member will act upon the switching assembly.

Abstract: The invention relates to a process for starting a vehicle with repeated forward-reverse run, in course of which in the drive-chain of the vehicle an automatic transmission /2/ is driven with an internal combustion motor /1/ through the incorporated hydrodynamic torque converter /16/ or in a given case with a dry friction clutch /15/ shortcircuiting it, either directly with the automatic transmission /2/ and/or the cardan shaft /3/, thereafter, by the aid of at least one differential gear /4/ and the half-axes connected thereto at least one pair of wheels /6/ is put into a rotary motion, while gear-change of the automatic transmission /included the function of the dry friction clutch /15// are carried out with an auxiliary energy having been controlled with electromagnetic valves /7/, furtheron fuel supply to the motor /1/ is controlled by means of a throttle pedal; the process can be characterized in that from the angular velocity--being proportional with the velocity of the vehicle being 3 km/h at most, prac

Abstract: Apparatus and method for periodic rotation of the rotor assembly of a turbogenerator during the time that it is not rotated in its normal manner for generating power, in which a continuously operating motor is periodically connected through an electrically controllable, torque-speed, clutch mechanism and a gear train to a gear mounted on the rotor shaft so as to rotate the shaft by 180.degree. at a slow speed. The position of the rotor is measured by electrically counting the teeth of the gear on the rotor shaft, and the count of teeth is compared with a preset number in a counter which after the count set in the counter is reached, disconnects the motor from the rotor gear and sets a brake. A settable timer periodically releases the brake and connects the motor to the rotor gear. The apparatus can include a recorder for recording rotation of the shaft and an alarm for indicating failure of rotation of the rotor when the timer provides a start signal.

Abstract: An improved automatic clutch control system for controlling a vehicle master clutch (16) drivingly interposed a throttle controlled engine (14) and a change gear transmission (12) in an automatic/semi-automatic mechanical transmission system (AMT) is provided. A monitored clutch parameter (CPV) is compared to a reference value (IEPCPV) to determine the expected point of incipient engagement of the clutch. The reference value is periodically updated, to compensate for wear and the like.

Abstract: In an automatic transmission for obtaining a necessary transmission gear ratio by disposing a plurality of gear trains on an input shaft 8 and an output shaft 19 which are parallel to each other, the present invention disposes two electromagnetic multiple-disk clutches C.sub.1 (or C.sub.2) and C.sub.5 (transmitting torque varying means) between the input shaft 8 and the output shaft 19 so that a torque is borne by the electromagnetic multiple-disk clutch C.sub.5 to make a shift operation at the time of shift-up and the torque is borne by the electromagnetic multiple-disk clutches C.sub.1 (or C.sub.2) and C.sub.5 to make the shift operation at the time of shiftdown. Accordingly, the torque from the engine can always be kept applied to the output shaft 19 during the gear change operation, and the occurrence of non-transmission of torque as well as the shock resulting from clutch connection can be prevented.

Abstract: A method for controlling an AMT system (10) is provided including sensing vehicle start from stop operation, determining a target engine speed value (A) based upon the operator setting of the throttle pedal (THL) and modulating the fuel supplied to the engine (FC) to cause the engine speed (N) to rapidly equal and then be maintained at said target engine speed value. The clutch (16) is engaged at a relatively slow first rate (106), or a relatively rapid second rate (126) depending upon the value of engine speed (N) relative to the target value (A) and upon the value of the amount (FC) and/or the rate of change of the amount (dFC/dt) of fuel supplied to the engine. The first rate of engagement is a function of, and varies directly with, the value of operator setting of the throttle (THL).

Abstract: In an apparatus for controlling a vehicle with an automatic transmission which includes a gear transmission and a clutch and is responsive to the operation of a selector and an acceleration member, the selector has a special position and a low-speed running mode is allowed when the special position is selected. During the low-speed running mode, the vehicle can be driven even when the amount of operation of the acceleration member is zero level, reducing the work of the driver, especially in heavy traffic.

Abstract: An automatic transmission includes a torque converter with a directly coupled clutch. A plurality of rotational speed sensors are used in the control of a lockup and a shifting operation. The invention provides an arrangement to detect any abnormality associated with such sensors. Under the lockup condition of the torque converter, a speed Ve detected by an engine rotational speed sensor, and speeds Vsp1 and Vsp2 detected by a first and a second vehicle speed sensor and a speed ratio K.sub.1 of a change gearing are used to detect any abnormality associated with the three sensors. All of the sensors are determined to be properly functioning when the equalities Ve=K.sub.1 .multidot.Vsp1 and Ve=K.sub.1 .multidot.Vsp2 apply. The first vehicle speed sensor is determined to be faulty when the former equation applies while the latter equation does not apply, and the second vehicle speed sensor is determined to be faulty when the former equality applies while the latter does not apply.

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: An automatic transmission system having a gear transmission comprises a detector responsive to the operation of switching OFF an ignition switch for detecting whether or not the actual gear position of the gear transmission matches the position set by a selector. When the result of the detection is that the actual gear position does not match the set gear position, the gear position of the gear transmission is changed to the right position corresponding to the position of the selector at the time the ignition switch is turned off. Thus, the gear transmission is sure to be in the right gear position whenever the ignition switch has been switched OFF.

Abstract: A lockup control system for a torque converter with a directly coupled clutch is disclosed. A gear ratio of the torque converter is detected as is a throttle valve opening. A gear ratio data (as a reference data) which is previously assigned to a throttle valve opening is read from ROM, and is compared against the detected gear ratio. If the latter is equal to or greater than the former, a lockup command is provided, and a prevailing vehicle speed is written into a register. When a lockup condition is established, the current vehicle speed is compared against the vehicle speed stored in the register, and whenever the former becomes equal to or less than the latter from which .DELTA.V is subtracted, the lockup is terminated. Reference data is provided in three groups corresponding to three temperature regions of the torque converter.