A vehicle includes a transmission having input and output shafts and clutches engageable in combinations to create power-flow paths between the input and output shafts. The vehicle further includes wheels driven by the output shaft and a controller. The controller is programmed to engage one of the combinations, and, responsive to the wheels slipping and a desired engine torque reduction exceeding a threshold, command capacity to an additional one of the clutches to reduce torque of the output shaft.

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.

Aspects of the present invention relate to a method of using a transmission with multiple clutches in order to provide improved methods of traction control on a hill ascent. Embodiments provide for the use of power-shift, automatic or dual clutch gearboxes.

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.

A continuously variable transmission (CVT) for a vehicle includes an input member, an output member and a variator assembly including a first pulley rotatably coupled to the input member and a second pulley rotatably coupled to the output. The first and second pulleys are rotatably coupled by a flexible continuous rotatable device. A control system is provided including an instruction set executable to determine an initial variator speed ratio of the variator assembly and detect an event causing a change in an operational state of the vehicle. The control system determines a compensation strategy to adjust the variator speed ratio in response to the change in the operational state of the vehicle and generates an adjusted variator speed ratio based upon the compensation strategy. The control system transmits the adjusted variator speed ratio to the variator assembly.

A vehicle controller includes a first abrupt deceleration determining unit configured to determine an abrupt deceleration state of a vehicle in a first manner, and a second abrupt deceleration determining unit configured to determine the generation of the abrupt deceleration state of the vehicle in a second manner having a required time for the determination shorter in comparison with that of the first manner, wherein any one of the first manner and the second manner is selected according to a vehicle speed of the vehicle or a road surface friction coefficient and used for determining the abrupt deceleration of the vehicle, the second manner is used in a region where the vehicle speed or the road surface friction coefficient is lower, and the first manner is used in a region where the vehicle speed or the road surface friction coefficient is higher.

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 continuously variable transmission (ECVT) system applicable to a motorcycle includes a first speed sensor, second speed sensor, continuously variable transmission (CVT) and control unit. The control unit receives a user control signal and accordingly controls a speed-changing state of the CVT. While the motorcycle is operating in a manual-operation mode, the control unit predicts, according to the user control signal, a first speed signal sent from the first speed sensor, and a second speed signal sent from the second speed sensor, whether the next gear indicated by the shift request signal will cause the motorcycle to move unsteadily. If so, the control unit ignores the shift request signal and refuses to perform gear shifting. If not, the control unit sends at least a shift control signal to the CVT so that the CVT performs gear shifting.

A vehicle drive-train with a drive engine, a drive output and a transmission device connected in the power flow between the drive engine and the drive output. The transmission device has at least two transmission units whose transmission ratios can be varied continuously, at least in some ranges, and which are arranged in power-trains running parallel with one another between the drive engine and the drive output. The power-trains can each be functionally connected with a respective axle of the drive output. At least one shifting element is provided by which the power-trains can be functionally connected in the area between the transmission units and the drivable axles. In addition, a method for operating the vehicle drive-train is described, in which the shifting element is actuated as a function of torque to be transmitted via the transmission device between the drive engine and the drive output.

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.