In an apparatus for controlling an automatic transmission connected to a prime mover mounted on a vehicle, having a torque converter equipped with a lock-up clutch, when predetermined operating conditions of the vehicle are satisfied at drive-off, a lock-up clutch engaging circuit is formed through a hydraulic supply circuit. Next it is determined whether engage-position sticking malfunction of the lock-up clutch has occurred based on a ratio of an input rotational speed of the automatic transmission relative to an output rotational speed of the prime mover and a change rate of the output rotational speed of the prime mover when the lock-up clutch engaging circuit has been formed, and fail-safe control is then implement when the sticking is determined.

A powertrain (12) for a vehicle (10) is disclosed. The power-train (12) comprises: a combustion engine (24), (ii) a drivetrain (14) having a torque converter (32) with a first state of operation in which the input (34) of the torque converter (32) is locked to the output (36) of the torque converter (32) and a second sate of operation in which the input (34) of the torque converter (32) is not locked to the output (36) of the torque converter (32) for allowing slippage. The drivetrain also has a final drive (44) for supplying torque to the drive wheel (16) from the torque converter (32), wherein the final drive (44) is coupled to the torque converter (32) at a fixed gear ratio. The powertrain (12) further comprises: (iii) a first electric motor (28) configured to supply torque to the drivetrain (14) on the output-side of the torque converter (32).

The present disclosure relates to a method for controlling a lock-up clutch of an automatic transmission. The method includes: a detecting step of detecting, by a controller, a current signal applied to a solenoid valve of an engaging element when a gear change operation begins; and a first increasing control step of controlling, by the controller, an amount of current that is applied to a solenoid valve of a lock-up clutch during an initial fill time period when it is determined that the current signal is applied to the solenoid valve of the engaging element. In particular, the solenoid valve of the engaging element is used to form a gear stage, and the controller increases the amount of current to a predetermined level for a predetermined period of time.

A method for operating a drivetrain of a motor vehicle, includes, when the motor vehicle is at a standstill and upon demand for a drive torque of the motor vehicle, increasing power (25p) supplied to a separate electric pump drive (25) such that a pressure chamber whose pressurization effects a complete closure or lock-up of a launch element (3) is fast charged with hydraulic pressure from a pump (24). The method also includes performing a launch process of the motor vehicle with the drive source (1) and with a closed or locked-up launch element (3) and reducing the power (25p) supplied to the separate electric pump drive (25) after fast charging the pressure chamber. A related drive train module is also provided.

The present invention provides a method and system of modifying a torque converter clutch control system having a hydraulic circuit including a solenoid signal line, a torque converter IN line, a torque converter OUT line, a lockup clutch apply line, and a supply presser line such that, in a valve body, a hole is drilled in a valve body to connect the solenoid signal line in a first area to a second differential area connected to the torque converter OUT line, and the torque converter OUT hole in the valve body casing is plugged.

A circuit for controlling hydraulic pressure of a torque converter that includes an engagement hydraulic pressure chamber independently installed in a fluid operation chamber enclosed by a front cover and an impeller and having engagement hydraulic pressure supplied to engage a lock-up clutch may include a torque converter control valve stably decreasing line pressure and supplying the decreased line pressure as operation hydraulic pressure of the torque converter, a torque converter pressure control valve controlled by a linear solenoid valve to control D range pressure and supply the controlled D range pressure to the engagement hydraulic pressure chamber, and a lock-up switch valve controlled by the linear solenoid valve to supply the hydraulic pressure supplied from the torque converter control valve as control pressure of the torque converter pressure control valve and supply exhaust hydraulic pressure of the torque converter as control pressure of the torque converter control valve.

A transmission includes a torque converter stator with controllable blade angle. A controller adjust the blades by commanding fluid pressures in hydraulic circuits routed to the stator hub. The controller also adjust the torque capacity of a torque converter bypass clutch by commanding fluid pressures in hydraulic circuits routed to apply and release chambers. Various schemes are presented to multiplex hydraulic circuits to serve multiple functions.

A transmission includes a torque converter stator with controllable blade angle. A controller adjust the blades by commanding fluid pressures in hydraulic circuits routed to the stator hub. The controller also adjust the torque capacity of a torque converter bypass clutch by commanding fluid pressures in hydraulic circuits routed to apply and release chambers. Various schemes are presented to multiplex hydraulic circuits to serve multiple functions.

A control device for a vehicle including a variable compression ratio mechanism arranged to vary an engine compression ratio of an internal combustion engine, and a torque converter which includes a lock-up mechanism, and which is disposed between the internal combustion engine and a transmission, has a controller configured to switch the engine compression ratio from a high compression ratio to a low compression ratio, and to switch the lock-up mechanism from a lock-up OFF state to a lock-up ON state. When the controller is switching the engine compression ratio from the high compression ratio to the low compression ratio, the controller starts switching the lock-up mechanism to the lock-up ON state when a current engine compression ratio is equal to or smaller than a permissible compression ratio which is between the high compression ratio and the low compression ratio.

If the difference between output torque output from an engine and load torque from drive wheels is large and torque input to a lockup clutch is large, since a value of lockup command pressure at which lockup engagement pressure in lockup end control becomes constant standby pressure is set to be high, fast release of the lockup clutch or racing of the engine is suppressed during the lockup end control. If torque input to the lockup clutch is small, the value of the lockup command pressure at which the lockup engagement pressure in the lockup end control becomes the constant standby pressure is set to be low, and a hydraulic pressure output period during which hydraulic pressure is output to the lockup clutch is set to be short.