Abstract: A lock-up control apparatus for a vehicle automatic transmission enables an engine stalling prevention at the time of a sudden deceleration in the lock-up state of a torque converter without causing the slip of the torque converter before the sudden deceleration, and prevents effectiveness of the fuel consumption from being sacrificed by a fuel cut. A controller performs the change-speed control on an automatic transmission through shift solenoids and on the basis of a throttle opening and a transmission output speed, and also performs the lock-up control of the torque converter through a lock-up solenoid. During the coasting drive when the throttle opening is set close to zero, the controller sets the torque converter to have a minimum lock-up capacity through the lock-up solenoid within such a range that no slip occurs.

Abstract: A lock-up controller of a lock-up control system reads-in a vehicle speed V, a throttle opening degree TVO, an engine speed Ne, and a turbine speed Kt from sensors and outputs a fuel-out command and a fuel-supply restart command to an engine controller, to operate a lock-up clutch in a torque converter of an automatic transmission for an automotive vehicle in an accelerator-off (coasting) state of the vehicle. The lock-up control system makes it possible to realize locking-up of the torque converter providing an improved fuel consumption ratio of the engine and a large braking force from the engine, even when a vehicle speed increases due to running down a downward slope while the accelerator-off state continues, or when an up-shifting speed change occurs due to the accelerator-off state.

Abstract: A system for controlling operation of a bypass clutch for a torque converter in an automatic transmission includes a converter lockout valve for producing a pressure signal having a first magnitude indicating unlocked operation of the converter clutch and a second magnitude representing locked operation, the pressure magnitudes being produced in response to control pressures representing engine speed, transmission operation in any forward gear, and in a first forward gear.

Abstract: A method for controlling preferably an electro-hydraulic automatic transmission of a motor vehicle fitted with a combustion engine provides a gradual kick-down while braking. In particular the kick-down is performed when, in the course of approaching a bend, a condition is activated, which prevents upshifting. The upshift prevention is initiated when the accelerator pedal is released quickly during shearing action. The upshift prevention stops if after an interval, upon detection of tensile action, the vehicle does drive round a bend. The upshift prevention is followed by a gradual adaptation of the gear level to the shift parameter.

Abstract: A method is provided for the control of the state of engagement of a damper clutch arranged in association with a vehicle engine, which has a fuel cut mechanism for suspending a supply of fuel during a decelerated operation, to permit connection between an input member and an output member in a torque converter arranged on an output side of the engine. Upon detection of a decelerated operation of the engine, the damper clutch is controlled to bring the input member and output member into a desired state of engagement. Here, the damper clutch is first released for a predetermined time and is then moved to an engaged side. Next, the damper clutch is feedback-controlled into a desired slip state so that the input member and the output member are allowed to rotate with a desired difference in revolution speed therebetween. A system for practicing the method is also described.

Abstract: A control system for engaging and releasing a torque converter bypass clutch and for varying the torque capacity of the clutch by adjusting the torque converter torus chamber pressure in accordance with changing operating variables, the bypass clutch including a clutch release pressure chamber that is maintained at a calibrated pressure threshold valve whereby pressure clutch capacity control is achieved by controlling pressure differential in the converter.

Abstract: A hydraulic control apparatus for an automatic transmission of a motor vehicle, the transmission including a lock-up clutch, the apparatus including a lock-up clutch switching valve device which is operable for selectively placing the lock-up clutch in a fully released, a partially engaged, and a fully engaged state thereof; a hydraulic pressure producing device which produces a hydraulic pressure; an abnormality detecting device which detects an abnormality of at least one of the lock-up clutch and the lock-up clutch switching valve device; and a control device which, when the abnormality detecting device detects the abnormality, operates the hydraulic pressure producing device for one of (a) applying the hydraulic pressure, and (b) inhibiting the hydraulic pressure from being applied, to at least one of the lock-up clutch and the lock-up clutch switching valve device for forcibly placing the lock-up clutch in one of the fully released and fully engaged states thereof.

Abstract: In a powertrain including an engine controlled by engine manifold conditions, a hydrodynamic torque converter having a bypass clutch, multiple ratio automatic transmission connected to the drive wheels of the vehicle, a solenoid-operated hydraulic valve, supplying pressurized fluid to engage and release the bypass clutch, is controlled by operation of a feedforward control system. An engine math model produces a signal representing predicted torque output by the engine, which signal is applied as input to an inverse mathematical model of the solenoid-operated valve that supplies hydraulic fluid to the bypass clutch.

Abstract: An automatic transmission system provided with a power take-off unit, which is composed of a torque converter equipped with a lock-up clutch and a control unit that serves to set the lock-up clutch ON/OFF. With the power take-off unit in operation, the control unit sets the lock-up clutch ON only when an engine output is determined to be higher than a predetermined level, and a shift lever is set in either neutral or parking position.

Abstract: Torque control method and apparatus for an internal combustion engine of a motor vehicle. A value of a desired drive shaft torque for the motor vehicle is determined on the basis of at least an accelerator pedal stroke for thereby controlling a drive shaft torque of the motor vehicle so as to assume the desired drive shaft torque value by controlling a gear ratio of a transmission gear coupling an output shaft of the engine to at least a drive shaft of the motor vehicle on the basis of the value of the desired drive shaft torque as determined. A gear ratio of the transmission gear and a flow rate of intake air fed to the engine are determined through different procedures in dependence on whether or not a torque transfer mechanism coupling the output shaft of the engine to an input shaft of the transmission gear is in a lock-up state in which the output shaft and the input shaft are coupled directly without slip.

Abstract: A hydraulic control circuit for an automatic transmission which has a plurality of hydraulic type frictional engagement elements for switching gear stages and a lockup clutch juxtaposed to a hydraulic power transmission device for transmitting engine power to the gearing. The hydraulic control circuit includes a lockup relay valve for switching oil pressure between an application side oil chamber and a release side oil chamber of the lockup clutch to apply and release the lockup clutch and a lockup switching valve for switching the lockup relay valve. A lockup control valve functions to increase the pressure difference between the application side oil chamber and the release side oil chamber at the time of application of the lockup clutch, as a signal pressure rises. A transient pressure control valve controls the transient pressure of a hydraulic frictional engagement element in accordance with the signal pressure.

Abstract: The present invention relates to a method and an apparatus for controlling a car equipped with an automatic transmission having a lockup clutch. According to the control method of the present invention, when the lockup clutch is in the lockup state, a variation of a generated torque is detected. When the range of the torque variation detected exceeds a predetermined value, an engine torque is reduced by controlling the engine, and the automatic transmission is controlled to compensate for a reduction of the driving torque due to a reduction of the engine torque. Thus, the speed change ratio is changed to the low gear side.

Abstract: An automatic transmission having a hydraulic torque converter and a multiple-ratio gear system in an automotive vehicle driveline wherein the converter includes a pressure-actuated bypass clutch and a control valve system for maintaining a regulated charge pressure in the torque converter and for controlling the actuation and release of the bypass clutch, the valve system including a main regulator that establishes a circuit pressure and that establishes priority distribution of pressurized fluid to the torque converter while temporarily interrupting distribution of pressurized fluid to the transmission lubrication circuit.