A method of controlling a continuously variable electric drivetrain (CVED) including a high ratio traction drive transmission and at least one of a first motor-generator and a second motor-generator is disclosed. The method includes the steps of receiving an output speed, determining a kinematic output speed, and determining a slip state of the high ratio traction drive transmission based on a comparison of the output speed to the kinematic output speed.

Devices and methods are provided herein for the transmission of power in motor vehicles. Power is transmitted in a smoother and more efficient manner by splitting torque into two or more torque paths. A continuously variable transmission is provided with a ball variator assembly having an array of balls, a planetary gear set coupled thereto and an arrangement of rotatable shafts with multiple gears and clutches that extend the ratio range of the variator. In some embodiments, clutches are coupled to the gear sets to enable shifting of gear modes. In some embodiments, the speed ratio of the ball variator is adjusted in concert with the adjustment of clutches.

A vehicle includes a power plant, continuously variable transmission (CVT), drive wheels, sensors, and controller. The CVT achieves a fixed gear/positive engagement and friction drive modes, and includes an input member that receives input torque from the power plant, an output member, and a variator assembly having drive and driven variator pulleys. The pulleys are connected to each other via an endless rotatable drive element, and to a respective one of the input and output members. Pulley actuators change a CVT speed ratio. The controller calculates a relative slip of the pulleys using measured speeds and displacements from the sensors, reduces the relative slip until the relative slip is below a calibrated speed limit or within a calibrated speed range via actuator control signal to the pulley actuators, and commands the fixed gear/positive engagement mode via positive engagement control signals to the CVT until the relative slip reaches zero.

In a control device of a vehicle power transmission device, a first meshing clutch has a drive power source side meshing member coupled to a power transmission member, an auxiliary drive wheel side meshing member coupled to the power transmission member, and an actuator engaging or releasing the drive power source side meshing member and the auxiliary drive wheel side meshing member, and when a rotation speed difference between a rotation speed of the drive power source side meshing member and a rotation speed of the auxiliary drive wheel side meshing member is larger than a predefined value at the time when a first meshing clutch is brought into an engaged state, a clamping pressure on a transmission belt is increased as compared to when a rotation speed difference is equal to or less than a predefined value.

A slip factor learning method of a dual clutch transmission (DCT) may include: determining, by a control unit, whether the DCT is up-shifted or down-shifted; comparing an engine speed to a shift start reference speed, and determining whether the engine speed enters an actual gear shifting period or actual gear shifting is completed, in response to the determined type of the gear shifting; comparing a magnitude of an engine torque to a magnitude of a clutch torque at a point of time that the engine speed enters the actual gear shifting period or the actual gear shifting is completed; and learning a slip factor at the point of time that the engine speed enters the actual gear shifting period or the actual gear shifting is completed, based on the magnitude comparison result between the engine torque and the clutch torque.

A transmission includes at least one shift element for which both the apply pressure and the release pressure are actively controlled. A controller adjusts the torque capacity of the shift element by varying the apply pressure and the release pressure in a coordinated fashion. During particular events, such as a shift event with the shift element as oncoming element or holding element, both the apply pressure and the release pressure are monotonically increased, mitigating the effect of hysteresis,

A protection control selection unit is provided. The protection control selection unit selects control that uses one of a completely engaging heat generation amount and a releasing heat generation amount, by which the amount of heat that is generated in a lockup clutch is reduced. The completely engaging heat generation amount is generated in the lockup clutch in a period before the lockup clutch is completely engaged from a state of lockup engagement control. The releasing heat generation amount is generated in the lockup clutch in a period before the lockup clutch is released from the state of the lockup engagement control. Thus, an increase in the temperature of the lockup clutch at the time when the lockup clutch is completely engaged or released from the state of the lockup engagement control is suitably suppressed.

A control device of a vehicle power transmission device for the vehicle power transmission device including a line pressure regulating device regulating a hydraulic pressure of a hydraulic fluid discharged from an oil pump to a predetermined line pressure while changing an opening area of a discharge flow passage, and an automatic transmission having a predetermined gear position established by engagement of a hydraulic friction engagement element by using the line pressure as a source pressure, the control device comprising: an abnormality determination portion configured to detect a slip of the hydraulic friction engagement element establishing the predetermined gear position at the time of establishment of the predetermined gear position and, if an input torque at the time of occurrence of the slip is equal to or greater than an abnormality determination value defined in advance based on a torque transmittable at a minimum line pressure by the hydraulic friction engagement element establishing the predetermined gear position, to make an abnormality determination indicative of a possibility of an abnormality causing the output hydraulic pressure of the line pressure regulating device to be the minimum line pressure while the opening area of the discharge flow passage is maximized, the abnormality determination value being defined in accordance with a rotation speed of the oil pump such that the abnormality determination value becomes larger when the rotation speed is high as compared to when the rotation speed is low.

A clutch includes a clutch disk that rotates by receiving motive power from an engine and a clutch plate switched between an engaged state in which it is engaged with the clutch disk and a disengaged state in which it is not engaged with the clutch disk. A controller calculates a coefficient of friction ? between the clutch disk and the clutch plate based on a time period ?t elapsed from a first time point when the number of relative rotations of the clutch disk and the clutch plate attains to a first number of rotations to a second time point when a second number of rotations smaller than the first number of rotations is attained, in a state in which the clutch disk rotates while transfer of motive power from the engine to the clutch disk is cut off and in the engaged state.

A continuously variable transmission (CVT) and a method is provided for CVT variator gross slip detection includes determining if a difference between a commanded variator speed ratio and a real variator speed ratio is greater than a predetermined variator speed ratio threshold, and then determining if a variator rate of change ratio is outside of predetermined variator rate of change ratio limits. Further, the method includes determining if a real torque capacity ratio is greater than a predetermined torque capacity ratio threshold, and performing at least one remedial action when the variator rate of change ratio is outside of predetermined variator rate of change ratio limits, and the real torque capacity ratio is greater than the predetermined torque capacity ratio threshold when the difference between the commanded variator speed ratio and the real variator speed ratio is greater than the predetermined variator speed ratio threshold.