A method is provided for controlling a drivetrain of a vehicle, wherein the drivetrain comprises a multi-clutch transmission. The gear shift of the multi-clutch transmission is adapted to be performed either by power cut shift or by power shift dependent on predetermined vehicle shift conditions. The method includes detecting at least one of a plurality of indications of slippery road conditions and setting a slip risk factor, wherein the slip risk factor is dependent on the indication of slippery road conditions. If the slip risk factor is above a first predetermined threshold value the method further comprises controlling the multi-clutch transmission such that an upcoming gear shift is performed as a power-shift independently of if upcoming shift was determined to be performed as a power-cut shift or as a power shift.

An ECU determines whether or not a road surface changes from a low μ road surface to a high μ road surface based on image data obtained by a camera sense. When the ECU determines that the accelerator pedal operation amount deceases greatly in a predetermined determination period from a time point at which a drive wheel slip state occurs in a case where the ECU determines that the road surface changes from the low μ road surface to the high μ road surface, it prohibits upshift operation of an automatic transmission over a predetermined period from that time point.

An ECU determines whether or not a road surface changes from a low road surface to a high road surface based on image data obtained by a camera sense. When the ECU determines that the accelerator pedal operation amount deceases greatly in a predetermined determination period from a time point at which a drive wheel slip state occurs in a case where the ECU determines that the road surface changes from the low road surface to the high road surface, it prohibits upshift operation of an automatic transmission over a predetermined period from that time point.

A control apparatus for a vehicle drive-force transmitting apparatus including a gear mechanism and a continuously-variable transmission mechanism provided in respective first and second drive-force transmitting paths. The control apparatus sets a target gear ratio of the continuously-variable transmission mechanism during a switching control operation that is executed to switch between (i) a first state in which the first drive-force transmitting path is established and (ii) a second state in which the second drive-force transmitting path is established, such that, when drive wheels are not being slipped, the target gear ratio is set to a highest gear ratio of the continuously-variable transmission mechanism, and such that, when the drive wheels are being slipped, the target gear ratio is set to an actual gear ratio at a point of time at which the drive wheels start being slipped.

A method is provided for controlling a drivetrain of a vehicle, wherein the drivetrain comprises a multi-clutch transmission. The gear shift of the multi-clutch transmission is adapted to be performed either by power cut shift or by power shift dependent on predetermined vehicle shift conditions. The method includes detecting at least one of a plurality of indications of slippery road conditions and setting a slip risk factor, wherein the slip risk factor is dependent on the indication of slippery road conditions. If the slip risk factor is above a first predetermined threshold value the method further comprises controlling the multi-clutch transmission such that an upcoming gear shift is performed as a power-shift independently of if upcoming shift was determined to be performed as a power-cut shift or as a power shift.

A control apparatus for a vehicle drive-force transmitting apparatus including a gear mechanism and a continuously-variable transmission mechanism provided in respective first and second drive-force transmitting paths. The control apparatus sets a target gear ratio of the continuously-variable transmission mechanism during a switching control operation that is executed to switch between (i) a first state in which the first drive-force transmitting path is established and (ii) a second state in which the second drive-force transmitting path is established, such that, when drive wheels are not being slipped, the target gear ratio is set to a highest gear ratio of the continuously-variable transmission mechanism, and such that, when the drive wheels are being slipped, the target gear ratio is set to an actual gear ratio at a point of time at which the drive wheels start being slipped.

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 system and method for controlling a vehicle having a continuously variable transmission (CVT) comprises a control system having at least one controller, an accelerometer and one or more sensors in communication with the at least one controller to monitor and detect a change in an operational state of the vehicle. The control system determines a vehicle acceleration rate with the accelerometer in response to the change in the operational state of the vehicle. An adjusted vehicle speed is computed based, at least in part, on the vehicle acceleration rate. A variator speed ratio is generated based upon the adjusted vehicle speed and transmitted to the variator assembly of the CVT.

Embodiments of the present invention provide a system comprising: a first controller configured in each of a predetermined plurality of states to generate a torque request signal in order to cause a vehicle to operate in accordance with a target speed value, the system being configured, when the first controller is one of said plurality of states to generate a gear shift limit signal to cause a change in an engine speed at which a transmission controller is permitted to cause a gear downshift, the gear shift limit signal being generated in dependence on at least one traction indicator signal indicative of an amount of estimated traction between the vehicle and a driving surface.

An electronic control unit is configured to, when the electronic control unit determines that any one of a first condition and a second condition is satisfied, preferentially execute lower limit speed ratio control. The first condition is a condition that, after the electronic control unit starts shift prohibition control, a wheel lock has occurred before a condition for cancelling the shift prohibition control is satisfied. The second condition is a condition that, after the electronic control unit starts the lower limit speed ratio control, a wheel spin has occurred before a condition for cancelling the lower limit speed ratio control is satisfied.