Abstract: A method and system for testing the functionality of a solenoid used to change the apply state of a torque converter clutch in a vehicle having an electronic control unit and a driveline system including an engine, a transmission, a torque converter. A first torque converter speed ratio is established. The commanded apply state of the torque converter clutch is determined, then a second torque converter speed ratio is calculated using engine speed and output shaft speed. The functionality of the torque converter clutch solenoid is established by determining whether the torque converter clutch solenoid has changed the applied state of the torque converter clutch by performing a comparison of the first and second torque converter speed ratios.

Abstract: A method for controlling a damper clutch when a vehicle having an automatic transmission requires increased power. For example, when accelerating while driving uphill, the present invention disengages a damper clutch. This advantage is obtained by identifying a power increase region on the damper clutch engaged region of operation such that the damper clutch is disengaged. The method for controlling the damper clutch includes a step of generating engine signal indicative of engine rpms and throttle position. A control signal is developing such that control of the damper clutch is based upon the generated engine signals.

Abstract: An apparatus for controlling of a lock-up clutch between a pump impeller and a turbine runner of a fluid-filled power transmitting device of a motor vehicle equipped with a fuel-cut control device for cutting a fuel supply to an engine when the engine speed is higher than a predetermined level, wherein a slip control device is provided to effect a deceleration slip control in which a pilot pressure for controlling the lock-up clutch is controlled during vehicle deceleration such that an actual slip amount of the clutch coincides with a target value, the apparatus including a monitoring device for determining whether the actual slip amount during the deceleration slip control by the slip control device is larger than a predetermined threshold, and a terminating device for terminating the deceleration slip control of the clutch by the slip control device, if the monitoring device determines that the actual slip amount is larger than the predetermined threshold.

Abstract: An apparatus for controlling a lock-up clutch for direct connection of an engine and an automatic transmission of a motor vehicle, the apparatus including a slip control device for selectively placing said lock-up clutch in one of a fully released state, a fully engaged state, and a partially engaged state, an uphill road detecting device for detecting that a road on which the motor vehicle is running is an uphill road; and a slip control inhibiting device for inhibiting the slip control device from placing the lock-up clutch in the fully or partially engaged state, if the uphill road is detected by the uphill road detecting device, so that undesirable repeated switching of the clutch between the fully released state and the fully or partially engaged state during uphill road running of the vehicle is prevented.

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 system for controlling operation of a bypass clutch for a torque converter in an automatic transmission includes a clutch capacity control valve, which connects a source of fluid pressure to a space between a converter clutch friction surface and an impeller casing in response to a force balance produced by variable pressure control signal and an unlock control pressure signal, produced by a converter lockout valve. The a clutch capacity control valve also supplies pressurized fluid to a torus of the torque converter. The valve includes four control lands connecting 10 ports, all of which are active and independent.

Abstract: When the change rate d.theta..sub.TH of an accelerator opening degree exceeds a reference value at a time point t.sub.0 as a result of the depression of an accelerator pedal, a predetermined target speed ratio eECONOMY taking preference of a specific fuel consumption up to such time is switched to a during-acceleration target speed ratio ePOWER taking preference of an accelerating performance. For a period from the time point t.sub.0 to a time point t.sub.2 until the actual speed ratio e reaches a minimum value, a feed-forward control is carried out in order to equalize the actual speed ratio e to the during-acceleration target speed ratio ePOWER. For a period from the time point t.sub.2 to a time point t.sub.3, a return-time target speed ratio eTRN gradually increased toward the predetermined target speed ratio eECONOMY is set, and a feed-back control is carried out in order to equalize the actual speed ratio e to the return-time target speed ratio eTRN.

Abstract: A lockup control system for automatic transmissions is constructed to prohibit lockup of a torque converter when detecting inertia cruising of a motor vehicle even if transition of the cruising state of the motor vehicle occurs from a converter area to a lockup area.

Abstract: A working fluid pressure control device for a hydraulic control system of a V-belt type continuously variable transmission comprises a line pressure regulator valve, a pressure reducer valve, a pressure modifier valve, in which the line pressure regulator valve developing a regulated line pressure for cylinder chambers of driving and driven pulleys of the transmission from a source pressure applied from a hydraulic pump driven by an engine associating with the transmission, the pressure reducer valve developing a reduced output pressure for a forward clutch and a reverse brake of the transmission from a source pressure supplied from the line pressure regulator valve, and the pressure modifier valve developing a pilot pressure for the line pressure regulator valve.

Abstract: The power train of a motor vehicle employs a torque transmitting apparatus having a hydrokinetic torque converter with a lockup clutch and a torsional damper between the output member of the clutch and the hub of the turbine in the cover of the torque converter. The torque capacity of the damper is less than the nominal torque of the engine whose output element drives the cover of the torque converter. The lockup clutch is designed in such a way that the transmission of torque from the cover to the damper can be regulated in several stages, one of which involves the transmission of torque within a range of between about 10% and 60% of the maximum torque transmitted by the engine and another of which involves the transmission of torque corresponding to not less than 60% of the maximum torque transmitted by the engine.

Abstract: An apparatus for controlling a lockup clutch provided in an automatic transmission having an impeller and a turbine. The pressure of the oil supplied to the lockup clutch is controlled by a lockup solenoid which is operable on a control signal having a variable duty cycle to operate the lockup clutch in a complete lockup mode to complete a mechanical connection between the turbine and the impeller and a released lockup mode to provide a hydrodynamic driving connection between the turbine and the impeller.

Abstract: A clutch slip control device includes: a slip revolution speed detecting circuit for detecting an actual slip revolution speed of a clutch; a memory unit for storing constants set to satisfy response and stability of a feedback control system of the slip conditions, the constants being determined by a high-order function approximating variation in input-output frequency characteristics of a plant input for actuating the clutch and the actual slip revolution speed; a first calculation circuit for calculating a first parameter using the constants stored in the memory unit, the first parameter discretely reflecting past data of the plant input, which are obtained in a current feedback control cycle through in a cycle executed a plurality of times before; a second calculation circuit for calculating a second parameter using the constants stored in the memory unit, the second parameter discretely reflecting past data of a deviation of the actual slip revolution speed from a target slip revolution speed, which are

Abstract: A lock-up control system for a fluid coupling, interposed between an engine and automatic transmission, which includes a lock-up clutch and is locked up by the lock-up clutch so as to directly couple the engine and the automatic transmission together, sets an increase rate, at which a locking pressure increases during locking of said fluid coupling, small at an early stage of locking and large at a later stage of locking.

Abstract: An apparatus for controlling a slip speed of a lock-up clutch interposed between an engine and an automatic transmission of a motor vehicle, the apparatus including a slip control device for effecting a deceleration slip control of the lock-up clutch during vehicle deceleration for controlling the slip speed of the clutch, a detector for detecting a currently established position of the transmission, or an operation of a vehicle braking system or an air conditioner, and a control terminating device for substantially terminating the deceleration slip control of the clutch when the speed of the transmission input shaft has been lowered to a threshold value which is determined depending upon the speed ratio of the currently established position of the transmission, or whether the braking system or air conditioner is in operation or not.

Abstract: The slip of a friction clutch between the engine and the transmission of a motor vehicle is regulated in such a way that the clutch is caused to operate with slip during transmission of torque which exhibits undesirable vibrations while the the RPM of the engine is within a first partial range, and that the clutch is prevented from operating with slip during transmission of torque which exhibits undesirable vibrations while the RPM of the engine is within second partial range.

Abstract: A lock-up clutch control method controls a torque converter comprising an input shaft through which a rotating force from an engine is input, an output shaft which outputs a driving force to the side of driving wheels and a lock-up clutch which operates in response to a hydraulic pressure. A control element controls an engaging pressure of the lock-up clutch by way of the hydraulic pressure. The engaging force of the clutch is controlled in accordance with calculated results of a target following up section for calculating a controlled variable so that a slip follows up a target slip and a control system stabilizing section for calculating the controlled variable so that the disturbance applied to the control system is compensated. Thereby, a stable control may be realized without receiving any effect of the disturbance. The disturbance may be estimated and learned for more accurate control.

Abstract: An apparatus including a slip control device for controlling an amount of slip of a lock-up clutch disposed between pump and turbine impellers in a power transmission system of a motor vehicle, such that an actual slip speed of the lock-up clutch coincides with a target slip speed, the apparatus comprising a hunting detecting device for determining the presence of a hunting defect if an amplitude of variation of the engine speed is larger than a predetermined first reference while an amplitude of variation of the turbine speed is not larger than a predetermined second reference.

Abstract: A control system for an engine-CVT drivetrain controls torque transmitting capacity of a lock-up clutch in response to drop of operator's power demand to keep hydraulic drive of a fluid coupling operable until a predetermined period of time passes after the subsequent increase of operator's power demand.

Abstract: An apparatus including a slip control device for controlling an amount of slip of a lock-up clutch disposed between pump and turbine impellers in a power transmission system of a motor vehicle, a slip-parameter monitoring device for detecting the actual slip speed of the lock-up clutch or a control error between actual and target slip speeds of the lock-up clutch, a summing device for obtaining a sum of values of the actual slip speed or control error detected by the slip-parameter monitoring device for a predetermined period of time, and a defect detecting device for determining the presence or absence of a defect in slip control of the lock-up clutch by the slip control device, on the basis of the sum as compared with a predetermined reference.

Abstract: A method of operating a torque transmitting system with a hydrodynamic power transmission and with a friction clutch, which constitutes a lock-up clutch and bridges the power transmission, involves controlling the lock-up clutch and the hydrodynamic power transmission so that clutch slip is present. The input torque furnished by a prime mover is divided into a torque which is to be transmitted by the power transmission and a torque which is to be transmitted by the lock-up clutch. The lock-up clutch includes an annular piston which is disposed between the cover and the turbine wheel of the power transmission. The radially outer portion of the piston constitutes a clutch disc and its radially inner portion is mounted on a complementary sealing hub. The power transmission is "soft" and exhibits a flat progress of the primary characteristic curve as well as a wide secondary characteristic curve, i.e., a wide torque conversion range.

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: 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: To prevent an alteration of the target slip amount of a lock-up clutch slip control due to changes over time of a automatic transmission, and moreover to improve fuel consumption without reducing drivability, a lock-up clutch is mounted inside a torque converter. Inside the lock-up clutch, operational oil is supplied while switching between a release state and an engaged state of the clutch according to the switching function of a clutch control solenoid. Furthermore, the arbitrary slip amount (slip rate) is regulated using these two components. As a result of these controls, there is mapping of the target slip amount in the operating ranges having as parameters the throttle aperture change rate and turbine rotational speed of a throttle valve included on the intake pipe of the internal combustion engine and the turbine rotational speed of the torque converter.

Abstract: A slip control apparatus provides a smooth response of actual slippage amount during a transitional period when a lock-up clutch is shifting from a disengaged state to a slipping state, and quickly determines a response to external disturbances when the slipping of the clutch is in a steady state. The apparatus has a first control unit for outputting a first control value based on the difference between target slippage amount and actual slippage amount, a second control unit for outputting a second control value based on the actual slippage amount, and a clutch pressure regulating unit for controlling an electromagnetic valve to control a lockup system on the basis of the sum of the first and second control values. The first control unit performs control for the transitional state of the lock-up clutch between the disengaged state and the slipping state.

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: A slip control apparatus for a fluid-operated lock-up clutch in a power transmitting system of a motor vehicle, wherein the amount of slip of the lock-up clutch is controlled such that the actual slip speed of the clutch coincides with a target value. The apparatus includes a device for establishing a restricted slip control mode if the vehicle running condition upon detection of a judder of the clutch is in a first area in which the clutch is likely to experience the judder. In the restricted slip control mode, the slip control of the clutch is inhibited while the vehicle running condition is in the first area, but is permitted while the vehicle running condition is in a second area in which the clutch is unlikely to experience the judder. The first and second areas of the vehicle running conditions are defined by parameters such as engine load or throttle valve opening and temperature of an oil used for operating the clutch.

Abstract: A lockup control apparatus and method of an automatic transmission engages a lockup clutch smoothly by gradually varying an electrical signal and holds a lockup pressure at a level corresponding to the engine load when the lockup clutch is engaged. The engagement of the lockup clutch is detected by comparing an engine rotational speed with a turbine rotational speed. The lockup pressure is determined at a minimal value enabling the lockup clutch to be engaged with a sufficient margin. Advantages of the lockup control apparatus are that shocks occured when the lockup clutch is engaged or disengaged can be attenuated and the life of the lockup clutch is substantially prolonged.

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: The invention is directed to a method and an arrangement for controlling the output power of a drive unit of a motor vehicle wherein a desired output torque command is determined on the basis of the driver command. A desired engine torque is computed from this desired output torque command while considering the torque transmission of a converter unit of an automatic transmission in all steady-state operating states. The converter unit is equipped with a controllable clutch. The desired engine torque is prepared by adjusting the output parameters of the engine.

Abstract: An apparatus for controlling a motor vehicle, including a fuel cutting device for cutting a fuel supply to an engine while a throttle valve is placed in an engine idling position, a clutch control device for effecting partial or full engagement of a lock-up clutch disposed in parallel with a fluid-filled power transmitting device while the throttle valve is placed in the engine idling position, an automatic cruising control device for controlling the throttle valve so that the vehicle runs at a substantially constant speed, and a restricting device for restricting or inhibiting the engagement of the lock-up clutch by the clutch control device while the throttle valve is controlled by the automatic cruising control device.

Abstract: An apparatus for controlling a lock-up clutch between pump and turbine impellers in a power transmitting system of a motor vehicle, including a slip control device for controlling the amount of slip of the lock-up clutch, and a judder detector for detecting a judder of the lock-up clutch based on the number of detected speed variations of the turbine impeller during slip control of the lock-up clutch by the slip control device, wherein the judder detector is inhibited from using a variation of the turbine impeller speed variation for the detection of the judder, if the amount of change of the variation amplitude is larger than a predetermined threshold or if the period of the variation is outside a predetermined range.

Abstract: Disclosed is a system for adjusting the working range of a damper clutch with reference to a linear function representing the relationship between the throttle valve position and the revolution per minute (rpm) of the engine in an automatic transmission of a vehicle, which includes a throttle valve position sensor for sensing the amount of opening of the throttle valve to generate an electrical position sensor signal, an engine rpm sensor for sensing the engine rpm to generate an electrical engine rpm signal, and a controller for changing the slope of the linear function according to the electrical position sensor signal and engine rpm signal by detecting the working of supplementary systems mounted in the vehicle for a driver's convenience.

Abstract: A lock-up control system for a torque converter, in a vehicle transmitting a driving torque of a prime mover to wheels via a power transmission unit including the torque converter which can establish direct coupling between an input element and an output element.

Abstract: An improved lockup control system for a lockup-type torque converter for automotive vehicle performs a coasting lockup control of a lockup clutch with minimized response delay of lockup releasing control and suppressed lockup releasing shock upon acceleration of the vehicle. The control system includes a controller that 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 region. The controller reduces the differential pressure across the lockup clutch to a lower limit value within a range in which the clutch can be prevented from slips. Thus, when the vehicle is reaccelerated and the driving condition shifts out of the lockup region, the reduction amount of the differential pressure is minimized to mitigate the response delay in the lockup releasing control.

Abstract: An apparatus for controlling the amount of slip of a lock-up clutch between pump and turbine impeller of a torque converter or other fluid-filled power transmitting device in a motor vehicle, the lock-up clutch including a piston which is operated by a pressure difference between pressures in two oil chambers on the opposite sides of the piston, and the apparatus including a slip control device for controlling the lock-up clutch according to a slip control output such that the actual slip of the lock-up clutch coincides with a target slip speed, and an output oscillating device for oscillating the slip control output to oscillate the pressure difference without vibrating the piston.

Abstract: The present invention relates to a hydraulic control system for an automatic transmission, including an oil pump, a plurality of shift valves for controlling a friction device in accordance with a vehicle's speed and transmitting a torque of a torque converter to a gear of a multi-stage transmission gear mechanism. A manual valve is provided for selectively supplying the hydraulic pressure generated from the oil pump to each shift valve by changing ports thereof. A reducing valve regulates the hydraulic pressure to be lower than a line pressure, and a pressure regulating valve receives a control pressure and changes the line pressure. A rear clutch exhaust valve directly supplies the hydraulic pressure supplied from the manual valve to a rear clutch in a first forward speed ratio of a drive "D" range. Two shift control solenoid valves supply the hydraulic pressure supplied from the manual valve to a second, a third and fourth speed lines in a second, a third, and a fourth forward speed ratios, respectively.

Abstract: An apparatus for controlling the amount of slip of a lock-up clutch connecting an input and an output rotary member of a fluid-filled power transmitting device of a motor vehicle, such that the actual slip speed of the lock-up clutch coincides with a target value, the apparatus including (a) a slip control device for providing a slip control output for controlling the clutch according to a slip control equation which includes at least an integral action term, and on the basis of a feedback control value for zeroing a control error between the actual and target slip speeds, and a learning control value which is updated depending upon the vehicle running condition, and (b) an output change restricting device for adjusting the feedback control value such that an amount of change of the slip control output provided by the slip control device is smaller than an amount of change of the learning control value.

Abstract: The present invention is directed toward determining when a clutch of an automatic transmission substantially fills with fluid. Once it is accurately determined when a clutch fills with fluid, then control over the transmission shifting may reliably be performed. The present invention determines when an on-coming speed clutch substantially fills with fluid in response to determining when an off-going speed clutch releases. Further, the present invention determines when an on-coming direction clutch substantially fills with fluid in response to determining when the torque converter output torque suddenly changes.

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: A slip control apparatus for a lock-up clutch disposed between pump and turbine impellers of a torque converter of a motor vehicle equipped with a traction control device for controlling a throttle valve of an engine so as to prevent excessive slipping of vehicle drive wheels, the apparatus including (a) a slip control device for controlling the amount of slip of the lock-up clutch such that an actual slip speed of the clutch coincides with a predetermined target value while the vehicle running condition is in a predetermined slip control area partially defined by the throttle valve opening, (b) a traction control monitoring device for detecting an operation of the traction control device, and (c) a clutch torque holding device for maintaining a present torque transmitting state of the clutch during operation of traction control device, by inhibiting a slip control operation of the slip control device or by maintaining the target slip speed of the clutch at the presently effective value.

Abstract: An apparatus for controlling an engine of a motor vehicle, and a lock-up clutch disposed between the engine and an automatic transmission for direct connection therebetween. The apparatus includes a lock-up clutch control device for engaging the lock-up clutch during deceleration of the motor vehicle, a vehicle deceleration detector for detecting a decelerating state of the motor vehicle, and an engine deceleration restrictor for restricting a rate of decrease of the engine speed for a period following detection of the decelerating state of the vehicle, so as to facilitate an engaging action of the lock-up clutch during deceleration of the vehicle.

Abstract: A lockup control system for automatic transmissions is constructed to prohibit lockup interruption control during shifting when the cruising state of a motor vehicle is such that a difference between an engine speed before and after shifting is smaller than a set value.

Abstract: A lockup control system for automatic transmissions is constructed to determine a rate of change of the drive duty of a lockup solenoid so that the drive duty has a value for obtaining the converter state of a torque converter within a set time determined for every type of shift.

Abstract: A torque converter clutch control having a controlled capacity mode of operation wherein clutch slip is controlled to a reference slip during periods of positive engine torque provides for a coast mode of operation wherein the clutch slip is controlled to a reference slip during periods of negative torque conditions. The control allows the drivetrain of the vehicle to couple torque to the engine thereby reducing fueling requirements and posturing the system for more efficient transitions into the controlled capacity mode. Drivetrain disturbances are not transferred to the vehicle by virtue of the controlled slip.

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: A torque converter lock-up clutch (26) control is provided which is adaptive to sensed torque demand across the torque converter (20) of a vehicular automated transmission system (12). Torque demand is, in one embodiment, sensed as a function of torque converter slip rate ((ES-IS)/(ES)), and torque converter lock-up is delayed upon sensed positive (ZNV ((ES-IS)/(ES)) torque converter slip rate.

Abstract: A control method is provided for an engine for a vehicle. The engine is arranged in association with a fluid coupling having a clutch. According to the control method, the state of engagement of the clutch is first detected. In the next step, it is determined whether or not the vehicle is in a predetermined decelerated operation state. When the clutch has been detected to be in a predetermined state of engagement in the clutch engagement state detection step and in addition, the vehicle has been determined to be in the predetermined decelerated operation state in the decelerated operation state determination step, an output of the engine is increased in the subsequent step.

Abstract: A locking-up hydraulic pressure control device of an automatic transmission comprises a memory, a controller, a second memory, and a time schedule management. The memory stores a hydraulic pressure control time schedule from the beginning of shift operation to the end. The controller means controls a locking-up hydraulic pressure in accordance with said hydraulic pressure control time schedule to be provided to a lock-up clutch that mechanically connects and disconnects a pump impeller of a torque converter of said automatic transmission connected to an engine and a turbine runner connected to transmission gears. The second memory stores a time schedule of engine revolution during a shift operation. The time schedule management means resets said hydraulic pressure control time schedule higher pressures than the former pressures in case if engine revolution exceeds said time schedule of engine revolution during the shift operation by a certain given limit.

Abstract: A method and device for simulating properties of a fluid torque converter such as torque ratio, capacity factor and efficiency includes involving the execution of the steps of finding a plurality of parameters including a fluid passage angle and a fluid passage resistance from a vane profile of a vane wheel of a fluid torque converter, and simulating the properties of the fluid torque converter according to the parameters and an input and output torque relationship based on an angular momentum theory. The fluid passage angle is corrected according to a slip ratio between rotational speeds of input and output ends of the fluid torque converter for the purpose of accounting for the influences of the occurrence of flow separation. Good results can be obtained by correcting the outflow angle of a stator vane array by using a correction value given as a mathematical function of the slip ratio. Thus, the accuracy of simulation can be substantially improved with a minimum increase in the computer time.

Abstract: A torque converter clutch control reduces or eliminates undesirable driveline disturbances through throttle position or load based criteria. A region of vehicle operation delineated by vehicle speed prone to driveline disturbances during certain vehicle operating conditions is used to predict such disturbances and disengage the torque converter clutch. Disturbances are cumulated and upon reaching a predetermined number of events the control substitutes certain torque converter clutch apply/release patterns to further reduce such disturbances.