A method for operating a hybrid drive train of a motor vehicle includes: starting the motor vehicle solely with the aid of an electric machine; engaging a torque converter lockup clutch for rotationally fixing an impeller of a torque converter to a turbine wheel of the torque converter, wherein the turbine wheel is rotationally fixed to the electric machine; and engaging a clutch in order to drivingly connect the impeller to a motor vehicle drive unit, in order to start the motor vehicle drive unit.

A method of controlling the electric current of a linear solenoid valve by performing pulse width modulation on a coil current for energizing a linear solenoid of the linear solenoid valve to adjust the hydraulic pressure of a working oil in a hydraulic clutch for transmitting and interrupting the rotational drive power from a power source to a drive wheel of a vehicle. The method includes setting the period of the pulse width modulation to a shorter value as the degree to which the hydraulic clutch is engaged increases from a disengaged state thereof. Here, the period of the pulse width modulation may be set in accordance with the variation of a duty ratio depending on the hydraulic pressure corresponding to the degree to which the hydraulic clutch is engaged.

A vehicle includes a clutch to couple a motor and transmission, and a controller that, in response to a regenerative braking request and a temperature being within a first range, partially capacitizes the clutch for regenerative torque transfer therethrough with slip, and in response to another regenerative braking request and the temperature being within a second range less than the first, fully capacitizes the clutch prior to regenerative torque transfer therethough to preclude slip.

A temperature-sensitive fluid fan clutch device includes an oil reservoir chamber in a case supported by a rotating shaft that has a drive disk fixed thereto. Plural dams are provided outward of the drive disk, and oil circulating flow passages contiguously to the dams extend between a torque transmission chamber and the oil reservoir chamber. A valve opens and closes an oil circulation flow hole of the oil reservoir chamber due to a change in temperature of a temperature-sensitive body. An oil effective contact area in a torque transmission gap between a drive side and a driven side is varied to control rotation torque transmission from the drive side to the driven side. An oil collection valve member independently opens and closes at least one of the oil circulating flow passages. The temperature-sensitive fluid fan clutch device inhibits a cold “drag” phenomenon and reduces fan power loss and fuel consumption.

In a transmission with a lockup clutch, in a case where zero-slip control of the lockup clutch is not established (converged) within a predetermined time, a sweep increase of a lockup clutch hydraulic pressure starts at an increase rate smaller than a normal increase rate in a case where the zero-slip control is established within the predetermined time, the increase rate until the end of the sweep increase is set to be equal to or less than the normal increase rate, and in addition, a hydraulic pressure at the time of the end of the sweep increase is set to be equal to or greater than a hydraulic pressure in a case where the zero-slip control is established within the predetermined time. With such control, in a case where the zero-slip state is not brought, suppressing the occurrence of shock when complete engagement is carried out.

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.

A hydrodynamic clutch having an input side and an output side, the rotational motions of which are coupled to one another with a hydraulic fluid. A method for determining the degree of filling of the hydrodynamic clutch with fluid including steps of periodically sensing a fluid temperature of the hydraulic fluid, determining the thermal output supplied to the clutch on the basis of the temperature, determining a lambda value on the basis of the thermal output and determining the degree of filling on the basis of the lambda value.

A control device for a lock-up clutch includes a control unit, an abnormality determination unit, a release control unit and a prohibition unit. The control unit is configured to control an engagement state of a lock-up clutch, and to perform a slip lock-up control by performing a feedback control of an engagement hydraulic pressure to be a first slip amount during coasting. The abnormality determination unit is configured to determine an abnormality when a state continues with a slip amount being equal to or greater than a second slip amount. The release control unit is configured to release the lock-up clutch when the abnormality is determined. The prohibition unit is configured to allow the control unit to raise the engagement hydraulic pressure by a prescribed pressure, and to prohibit determination by the abnormality determination unit, when the transmission ratio is downshifted during coasting while the slip lock-up control is performed.

A method for operating a hybrid drive train of a motor vehicle includes: starting the motor vehicle solely with the aid of an electric machine; engaging a torque converter lockup clutch for rotationally fixing an impeller of a torque converter to a turbine wheel of the torque converter, wherein the turbine wheel is rotationally fixed to the electric machine; and engaging a clutch in order to drivingly connect the impeller to a motor vehicle drive unit, in order to start the motor vehicle drive unit.

A system for determining a torque converter clutch is stuck in an engaged position includes a control module, an engine speed sensor, and a transmission speed sensor. The control module evaluates the torque converter clutch by determining a value of a torque converter clutch command. The torque converter clutch command indicates a position of the torque converter clutch. In response to determining that the value of the torque converter clutch command indicates the disengaged position, the control module calculates accumulated slip based on the transmission speed and the engine speed during an evaluation time. In response to determining the evaluation time is complete, the control module compares the accumulated slip with a calibrated threshold of slip. In response to the accumulated slip being less than or equal to the calibrated threshold of slip, the control module determines the torque converter clutch is stuck in the engaged position.