A diagnostic system of a vehicle for diagnosing a drive belt of a continuously variable transmission. A diagnostic circuit detects or predicts a fault of the drive belt based on an operating parameter received from a sensor associated with the vehicle during a predetermined diagnostic period.

A CVT is provided with a primary pulley (1) and a secondary pulley (2) between which a belt (3) is wound, and hydraulic pressure control valves (5, 6, 7) which control pulley hydraulic pressures. A CVT controller (8) sets a base current indicated value to be output to solenoids (5a, 6a, 7a) of the hydraulic pressure control valves (5, 6, 7), on the basis of a pulley hydraulic pressure indicated value. A dither control unit (58) of the CVT controller (8) superimposes a dither current onto the base current indicated value to be output to the solenoids (5a, 6a, 7a) if, during pulley hydraulic pressure control, the situation is determined, on the basis of belt slip determination information, to be such that belt slipping is highly likely to occur.

A diagnostic system of a vehicle for diagnosing a drive belt of a continuously variable transmission. A diagnostic circuit detects or predicts a fault of the drive belt based on an operating parameter received from a sensor associated with the vehicle during a predetermined diagnostic period.

A vehicle control device includes a belt slippage determination unit which determines whether or not slippage of a belt has occurred based on rotation of a drive pulley and rotation of a driven pulley, an output state determination unit which determines an output state of a sensor that acquires a signal corresponding to the rotation of the driven pulley, and a speed of rotation limitation unit which controls an upper limit of the speed of rotation of the drive source based on the output state of the sensor when slippage of the belt is detected by the belt slippage determination unit.

A method for controlling a pulley of a vehicle having a continuously variable transmission may include: determining, by a controller, a pulley target torque and a target pulley ratio, upon detecting disturbance of the vehicle; determining, by the controller, target pressures of a driving pulley and a driven pulley based on the pulley target torque and the target pulley ratio and comparing the target pressures with each other; and controlling, by the controller, a pressure of a pulley having a larger target pressure in the comparing to be a maximum pressure generatable depending on a traveling situation of the vehicle and controlling a pressure of the other pulley to be increased to a correction pressure for implementing the target pulley ratio.

A method for controlling a pulley of a vehicle having a continuously variable transmission may include: determining, by a controller, a pulley target torque and a target pulley ratio, upon detecting disturbance of the vehicle; determining, by the controller, target pressures of a driving pulley and a driven pulley based on the pulley target torque and the target pulley ratio and comparing the target pressures with each other; and controlling, by the controller, a pressure of a pulley having a larger target pressure in the comparing to be a maximum pressure generatable depending on a traveling situation of the vehicle and controlling a pressure of the other pulley to be increased to a correction pressure for implementing the target pulley ratio.

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.

A control apparatus for a drive-force transmitting apparatus that includes a gear mechanism and a continuously-variable transmission mechanism including primary and secondary pulleys and actuators that apply first and second thrusts to the respective first and second pulleys. When a target gear ratio of the continuously-variable transmission mechanism is a highest gear ratio in a gear running mode, the control apparatus sets a value of the thrust ratio, which is used when calculating a target value of a secondary thrust, to a value that increases a difference between a lower limit value of the primary thrust and the target value of the secondary thrust, and sets a value of the thrust ratio, which is used when calculating a target value of the primary thrust, to a value that increases a difference between the target value of the secondary thrust and the target value of the primary thrust.

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.

A diagnostic system of a vehicle for diagnosing a drive belt of a continuously variable transmission. A diagnostic circuit detects or predicts a fault of the drive belt based on an operating parameter received from a sensor associated with the vehicle during a predetermined diagnostic period.