A control apparatus for a vehicle, which is provided with a drive power source, drive wheels and a continuously variable transmission, includes a friction-force control portion configured to control a friction force acting between a belt and pulleys of the continuously variable transmission, based on a belt-slip information received from an external device located outside the vehicle. The belt-slip information represents at least one belt slippy area in which a belt slippage is more likely to occur in the continuously variable transmission. The friction-force control portion controls the friction force such that the friction force is made larger in the at least one belt slippy area than in other areas in which the belt slippage is less likely to occur in the continuously variable transmission.

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.

CVT controller has rotation speed sensors detecting driving and driven wheel rotation speed; driving and driven wheel speed difference detection unit detecting wheel speed difference vfr; and bad road judgment unit judging that road is bad road when vfr is first value vfr_br or greater. CVT controller further has first belt clamping force increase unit increasing belt clamping force in case where road is judged to be bad road, as compared with case where road is not judged to be bad road; vibration detection unit detecting vehicle speed vibration fvsp; and second belt clamping force increase unit increasing belt clamping force when vfr is second value vfr_psec or greater or when fvsp is third value fvsp_psec or greater in case where road is not judged to be bad road, as compared with case where vfr is less than vfr_psec and case where fvsp is less than fvsp_psec.

A method is described for determining a reference value of an actuating current that corresponds to a defined operating point of an electro-hydraulically actuated frictional shifting element of a continuously variable power-branched transmission, at which the shifting element transmission capacity is zero, and starting from which an increase of actuating force immediately increases the transmission capacity. The actuating current reference value of the shifting element, when closed with a further shifting element decoupled from the transmission output and when a transmission input rotational speed is higher than a defined threshold, is reduced until a rotational speed difference between the rotational speeds of the shifting element halves exceeds a predefined limit value such that, at the time when the limit value is exceeded, the reference value of the actuating current is the reference value of the actuating current that corresponds to the defined operating point of the shifting element.

An instantaneous revolution speed Nm of an input shaft is calculated from an input period of a pulse signal from a revolution sensor, a revolution speed Nf is calculated by filter processing the instantaneous revolution speed Nm, a determination is made that a belt slip occurs when, during a stop of a vehicle, a state in which the revolution speed Nf is equal to or higher than a slip determination speed N.sub.SL is continued for a time equal to or longer than slip determination time T.sub.SL, and an immediately prior revolution speed Nf is held until a time of a pulse signal no input exceeds a road wheel lock corresponding time T.sub.WL which is longer than a slip determination time T.sub.SL.

A continuously variable transmission (CVT), a transmission control system, and a method is provided. The control system is configured to determine a measured wheel speed of two driven wheels and a first driving wheel, calculate a first driving wheel expected speed based on the driven wheel measured speeds, a track width, and a wheel base, and calculate an actual wheel speed difference between the first driving wheel measured speed and the additional wheel measured speed. The additional wheel can be either of the driven wheels or a second driving wheel. The control system is also configured to calculate a theoretical wheel speed difference between the first driving wheel expected speed and the additional wheel measured speed, calculate a zeroed-out wheel slip based on the difference between the actual wheel speed difference and the theoretical wheel speed difference, and determine whether the zeroed-out wheel slip exceeds a predetermined threshold.

A method and an apparatus for controlling a clutch of a vehicle include determining whether a vehicle is moving under a condition in which a gearshift is coupled to the clutch. A clutch torque is learned in which the clutch is maintained in a micro-slip state by decreasing a target clutch torque for a corresponding gear level when it is determined that the vehicle is moving under the condition in which the gearshift is coupled to the clutch. Learning reliability is calculated by reflecting a difference between an engine torque and clutch torque. The clutch is maintained in the micro-slip state for the clutch torque learning or converting the clutch into a lock-up state, depending on a learning reliability level.

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.

Systems and methods for controlling transmissions having CVTs are disclosed with multiple modes and gearing arrangements for range enhancements, where embodiments include synchronous shifting to allow the transmission to achieve a continuous range of transmission ratios, while minimizing empty cycling of the CVT during mode shifts. Embodiments provide for wide ratio range and performance and efficiency flexibility, while maximizing CVT usage through synchronous shifting.

A control device of a powertrain with a centrifugal pendulum damper is provided comprising a power transmission shaft which transmits power between a drive source and an automatic transmission, and a centrifugal pendulum damper which is coupled to the power transmission shaft and a connection/disconnection mechanism. The automatic transmission has a transmission mechanism of a hydraulic pressure control type, which includes a transmission control module which performs a control to supply transmission hydraulic pressure to the transmission mechanism. The transmission control module includes a transmission characteristic changing module which changes a control characteristic of transmission hydraulic pressure according to an engagement degree of the connection/disconnection mechanism.