A control apparatus for a vehicle provided with (i) a power source, (ii) drive wheels and (iii) a fluid transmission device disposed between the power source and the drive wheels and including a lockup clutch to which a fluid pressure is supplied. A feedback control is executed for correcting a command value of the fluid pressure by a correction amount such that an actual value of a slip amount of the lockup clutch becomes substantially equal to the target value of the slip amount in a slip control. When the actual value has been converged into a given range with respect to the target value, the correction amount is obtained, and the command value for a next execution of the slip control is corrected by learning with use of the obtained correction amount. The given range is set depending on the target value of the slip amount.

A method for calibrating an actuation of a converter lock-up clutch of a hydrodynamic torque converter having a pump wheel and a turbine wheel connected to a power-split transmission. The transmission has at least two clutches each connected to a respective power-split shaft assembly and each configured be actuated separately to close and open in order to apply a clutch torque to the turbine wheel so that a rotation speed difference between the pump wheel and the turbine wheel changes. The method includes opening the converter lock-up clutch and the at least two clutches each connected to a respective power-split shaft assembly of the transmission, rotating the pump wheel with a specified rotation speed, and applying a clutch torque to the turbine wheel as a function of an actual rotation speed difference. Clutches connected to a different respective power-split shaft assembly of the transmission are actuated in the closing direction.

The controller starts an output of an engagement instruction of the lockup clutch when a vehicle speed becomes a lockup start vehicle speed under a state where the lockup clutch is disengaged. When the vehicle speed, which is obtained a predetermined time after the output of the engagement instruction is started due to the vehicle speed becoming the lockup start vehicle speed, has reached a predetermined vehicle speed, the controller continues the output of the engagement instruction. When the vehicle speed has not reached the predetermined vehicle speed, the controller stops the output of the engagement instruction and restarts the output of the engagement instruction when the vehicle speed reaches a lockup restart vehicle speed which is set to a vehicle speed higher than the lockup start vehicle speed while the output is stopped.

A control method is provided for controlling an internal combustion engine for a vehicle configured to engage a lockup clutch during a fuel cut, and to decrease a lockup hydraulic pressure at a fuel cut recovery to bring the lockup clutch to a slip engagement. The control method includes estimating a torque of the internal combustion engine generated by the fuel cut recovery when a fuel cut recovery condition is satisfied. The control method further includes decreasing a decrease amount of the lockup hydraulic pressure as the torque is greater.

In one aspect, a control method and a control apparatus are provided for protecting a damper clutch of a vehicle. In one aspect, the control method of protecting the damper clutch of the vehicle includes determining whether a vehicle state satisfies a condition for operating a damper clutch protection logic, calculating a slip power in real time on the basis of a turbine speed of a torque converter, an engine speed, a capacity coefficient of the torque converter, a clutch torque, and a hydraulic torque when the condition for operating the damper clutch protection logic is satisfied, determining whether a repetitive tip-in/tip-out that is intentionally performed occurs or not on the basis of a change in the slip power that is calculated in real time for a set time, and operating the damper clutch protection logic for restraining a slip of the damper clutch when there is the repetitive tip-in/tip-out that is intentionally performed.

In a control apparatus for a vehicle, in the cases where engine torque is higher than first torque and an engine torque change amount is larger than a first torque change amount when control is shifted from complete engagement control of a lock-up clutch to deceleration slip control, an electronic control unit is configured to shift the control from the complete engagement control to acceleration slip control and then shift the control from the acceleration slip control to the deceleration slip control after the vehicle is brought into a driven state.

A lock-up clutch control device that sets a hydraulic pressure command value for a lock-up clutch as a starting device together with a pump impeller coupled to a motor of a vehicle and a turbine runner coupled to an input shaft of a transmission such that an actual rotational speed difference between the motor and the input shaft coincides with a target slip speed that matches a state of the vehicle, and that controls the lock-up clutch based on the hydraulic pressure command value.

A control apparatus for a lockup clutch is provided. The control apparatus for the lockup clutch includes an electronic control unit that is configured to: calculate a driven target clutch torque capacity and a driving target clutch torque capacity; set a target clutch torque of the lockup clutch and control the lockup clutch, based on the driven target clutch torque capacity and the driving target clutch torque capacity; and change over the target clutch torque capacity from the driven target clutch torque capacity to the driving target clutch torque capacity when the driven target clutch torque capacity and the driving target clutch torque capacity coincide with each other after an operation state of an accelerator of the vehicle changes over from an accelerator OFF state to an accelerator ON state.

A powertrain includes a torque generative device and a torque converter having an impeller, a turbine and a torque converter clutch. A method to control torque converter slip includes a feedforward component and a feedback component. The feedforward component includes monitoring a reference slip, and actual slip, and a turbine speed of the torque converter, determining a desired turbine torque based upon the reference slip and the turbine speed, determining an actual turbine torque based upon the actual slip and the turbine speed, determining a feedforward torque converter clutch pressure command based upon the desired turbine torque, the actual turbine torque, a torque generative device torque, and a TCC gain, and determining feedforward torque converter clutch pressure command. The feedback component modifies the feedforward command pressure based on proportional plus integral plus differential (PID) slip feedback terms.

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.