Abstract: A lock-up controller is provided for shifting a torque converter of a vehicle from the lock-up state to the unlock state when the accelerator pedal is depressed at a speed larger than a predetermined speed when the vehicle is coasting, The controller is further functioning to prevent the torque converter from shifting to the lock-up state when the torque converter has been shifted to the unlock state and the vehicle speed is within the predetermined re-lock-up prevention speed range so as to avoid frequent lock-up/unlock operation of the torque converter.

Abstract: A torque converter automatic transmission of a motor vehicle is equipped with an overheat prevention system of the torque converter.

Abstract: The present invention is a control device and a control method for a transmission with a clutch, by which the clutch is smoothly coupled without generation of shocks or the like in a vehicle.

Abstract: A method for reducing transmission clutch engagement pressure during conditions when clutch hydraulic fluid is relatively more viscous. A clutch engagement pressure control signal is shaped by a system that has an addition branch (42) for shaping the control signal as the control signal is rising, a subtraction branch (44) for shaping the control signal as the control signal is falling, and a summing junction (46) for algebraically summing the signal outputs of the addition and the subtraction branches.

Abstract: A transmission assembly and method for controlling a torque converter of a transmission assembly in which an electronic controller monitors the load on the vehicle power train in addition to a number of other vehicle dynamics, including the currently engaged gear ratio and the temperature of the transmission fluid. The electronic controller is operable for causing the activation of the converter clutch in response to a number of predetermined operating conditions, one of which includes the operation of the vehicle when the fluid in the torque converter exceeds a predetermined temperature and the vehicle power train is operated under a heavy load for a period of time which exceeds a predetermined time interval. Engagement of the converter clutch during such times inhibits relative rotation between the torque converter turbine and impeller, improving fuel economy and preventing the torque converter from generating a substantial amount of heat.

Abstract: A device for controlling an automatic transmission and an engine for vehicles expanding a range of direct drive to improve fuel efficiency and decreasing the shock due to the transmission of torque at the time of acceleration or deceleration.

Abstract: A method and an apparatus control a car equipped with an automatic transmission having a lockup clutch. 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: A lock-up control apparatus and method for a torque converter of an automatic power transmission associated with a vehicular internal combustion engine driven in a plurality of engine driving modes, such as a lean burn mode. A lock-up region of a map for the torque converter is modified toward a higher vehicle speed when the engine operates in one of the driving modes such that an engine output torque value becomes large under the same engine load conditions as those when the engine is driven in any one of the other driving modes in which the engine output torque is small. The lock-up region is extended up to a higher engine load region when the engine operates in one of the driving modes such that the engine output torque is small under the same load condition.

Abstract: An apparatus for controlling a lock-up clutch between pump and turbine impellers in a fluid-filled power transmitting device of a motor vehicle, such that a slip control device controls the actual slip speed of the lock-up clutch so as to coincide with a transient target slip speed, the apparatus including a device for calculating a final target slip speed of the lock-up clutch which assures a maximum fuel economy of the vehicle during a steady-state running, a device for setting, as an initial value of the transient target slip speed, a difference between the speeds of the pump and turbine impellers immediately before an operation of the slip control device is initiated, and a device for reducing the transient target slip speed toward the final target slip speed at a rate which decreases as the transient target slip speed approaches the final target slip speed.

Abstract: A powertrain for a vehicle includes an engine, a multi-speed transmission and control, and output drive mechanisms. The transmission has an electro-hydraulic control for establishing the transmission drive ratios and the interchange therebetween. The ratios are established by a plurality of friction devices, one of which is engaged for the lowest forward ratio. The control has a microcomputer which evaluates vehicle operating parameters and maintains the transmission properly controlled in response to various input signals. The transmission is maintained in an auto neutral condition when the engine is at idle, the transmission output speed is zero, the vehicle brakes are engaged and the forward drive has been selected. The control continually adjusts the pressure in the one friction device to maintain the torque capacity thereof in a range less than full engagement and greater than a minimum value.

Abstract: A hydraulic control system for an automatic transmission having at least a forward clutch which is unlocked in a fourth gear and locked in other forward gears and a lock-up clutch for coupling input and output elements of a torque converter together is equipped with a pressure control valve for controlling operating pressure for the forward clutch, a lock-up control valve for connecting and disconnecting the first valve from the lock-up clutch, a pressure line through which control source pressure is introduced into the forward clutch while the first valve is in communication with the lock-up clutch, and a shift valve for discharging the control source pressure from the pressure line.

Abstract: A lockup control system for an automatic transmission is provided with an electromagnetic valve 11 and a spool valve 13. When the electromagnetic valve 11 is inactive, the spool valve 13 is set so that a pressure at an OFF port 171 of a torque converter 12 is higher than that of an ON port 172, thereby opening a lockup clutch mechanism 19. When the electromagnetic valve 11 is activated, its control pressure Pc becomes lower than a secondary pressure PL2and the spool valve 13 is actuated so that the control pressure Pc is supplied to a clutch control chamber 18. As a result, the lockup clutch mechanism 19 is closed, thereby setting the lockup state. At this time, the control pressure Pc acts directly on the clutch control oil chamber 18, so that the lockup clutch mechanism 19 is controlled with high precision.

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: In response to a signal indicating the present throttle valve opening degree detected by a throttle valve sensor and a signal indicating the present vehicle speed detected by a vehicle speed sensor, a lock-up controller determines whether a lock-up clutch should be brought into the operatively connected state or it should be released from the operatively connected state, and on completion of the foregoing determination, the controller outputs a certain signal to a solenoid valve. In the case that the lock-up clutch has been released, this state is maintained. On the contrary, in the case that the lock-up clutch has been in the operatively connected state, the controller determines whether maintains this state or selects a lock-up clutch releasing pattern depending on the present throttle valve opening degree.

Abstract: An improved lockup control system for a lockup-type torque converter including a lockup clutch performs a lockup releasing control of the lockup clutch with a satisfactory response characteristic at any input torque of the torque converter without causing a lockup releasing shock. The control system includes a controller which is operative when the driving condition of a vehicle as represented by the throttle valve opening and the vehicle speed is judged to belong to a lockup releasing region, to reduce the differential pressure across the lockup clutch for disengaging the lockup clutch and thereby releasing the lockup. On such occasion, in the first place, the differential pressure is set to an initial differential pressure immediately before the lockup clutch begins to slip, depending upon the input torque of the torque converter at the instant of the lockup releasing command.

Abstract: A method and an apparatus for controlling a car equipped with an automatic transmission having a lockup clutch. According to the control method 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 apparatus is disclosed which prevents occurrence of an engine stalling in a power train of an automotive vehicle, including an engine and a lock-up type automatic transmission. The apparatus is operative during a braking operation of the vehicle and includes an engine controller to perform an idling speed control for the engine, and a transmission controller to perform a lock-up releasing control for releasing the torque converter from the lock-up mode. When the lock-up releasing control is being performed, the engine controller continuously performs the idling speed control and thereby prevents occurrence of engine stalling.

Abstract: A hydraulic circuit for a lock-up device includes a valve arranged in an oil path for supplying hydraulic pressure to a hydraulic power transmission. The valve regulates flows of hydraulic oil discharged toward a cooling circuit or a lubricating circuit, corresponding to a signal in relation to an engine torque. Therefore, corresponding to the engine torque, it is possible to maintain the hydraulic pressure for the hydraulic power transmission, which is necessary for lock-up condition of the lock-up device.

Abstract: In a driving zone where a torque converter is to be locked up, a lockup force of a lockup clutch is weakened in the deceleration driving state compared with that in the non-deceleration driving state. Moreover, during transition from the deceleration driving state to the non-deceleration driving state, increase control of the lockup force is forcedly delayed for a predetermined time. By this, during acceleration from the deceleration driving state, the clutch is made to slip with a rapid increase in engine output torque and a rise in the engine output torque is buffered by the lockup clutch.