Provided herein is a method for calibrating a clutch by searching for the minimum of a multi-dimensional surface including determining the error between a spline function and recorded data relating to clutch characteristics, creating a multi-dimensional surface corresponding to the error values, determining the minimum of the multi-dimensional surface using the steps of performing a Steepest Gradient & Direction determination step and conducting a Golden Section Search and Switch Direction Step to find a minimum that meets a predetermined closing condition. Additionally, provided herein is a computer-implemented system for calibrating the clutch.

A drive system of a hybrid vehicle including an internal combustion engine, a first motor-generator, a power division mechanism, a speed change mechanism including a second output shaft, a second motor-generator including a third output shaft connected to a power transmission path transmitting a power from the second output shaft to an axle, a one-way clutch interposed between the second output shaft and the third output shaft in the power transmission path, and an electric control unit including a microprocessor to control the speed change mechanism. The speed change mechanism includes a first engagement mechanism and second engagement mechanism, and the microprocessor is configured to control the speed change mechanism so as to disengage one of the first engagement mechanism and the second engagement mechanism in engaged state and engage the other thereof in disengaged state, in accordance with a speed change instruction.

A vehicle traction control system for a vehicle, in which the vehicle has a prime mover, at least one wheel for providing tractive effort on a support surface, and a transmission having an input side operably coupled to the prime mover and an output side operably coupled to the at least one wheel, and in which the transmission has a controllable clutch pressure between the input side and the output side, includes a controller operable to monitor wheel slip of the at least one wheel. When wheel slip is detected the controller is operable to control the clutch pressure for modulating an output torque of the transmission for reducing the wheel slip. The clutch pressure can be controlled as a function of clutch slip.

Methods and systems are provided for operating a vehicle driveline where the vehicle driveline does not include a torque converter. In one example, a method comprises controlling a capacity of a clutch configured to transmit torque between an engine and a transmission, and an output of an electric motor positioned in a driveline of the hybrid vehicle during a vehicle launch to emulate a performance of a torque converter positioned in the driveline of the vehicle. In this way, vehicle launch maneuvers may be conducted for vehicles that are equipped with a clutch and an electric motor, such that said launch maneuvers mimic those of a vehicle with a torque converter, which may improve customer satisfaction and improve engine efficiency.

Methods and systems are provided for starting an engine in a hybrid vehicle. In one example, a method includes cranking an engine of the vehicle by controlling a capacity of a clutch of a dual clutch transmission positioned downstream of the engine and compensating for driveline disturbance resulting from the cranking via controlling an electric machine positioned downstream of the dual clutch transmission. In this way, engine starting may be conducted under a variety of vehicle operating conditions.

The invention relates to a method for determining a characteristic curve of a hybrid separating clutch of a hybrid vehicle without a test stand, wherein the hybrid separating clutch separates or connects an internal combustion engine and an electric motor and the hybrid separating clutch is slowly actuated on the basis of a position which the hybrid separating clutch assumes in an unactuated state, and a clutch characteristic curve is determined as a function of a clutch torque over a path of the hybrid separating clutch. In a method by which a characteristic curve of the hybrid separating clutch can be reliably defined without a test stand, a clutch torque which underlies the characteristic curve of the hybrid separating clutch is determined from the torque of the internal combustion engine in the case of a running internal combustion engine and a motion state of the electric motor which brakes the internal combustion engine while the hybrid separating clutch is moving.

A vehicle includes a powertrain and a controller. The powertrain includes a transmission torque converter having a bypass clutch disposed between an electric machine and a drive wheel. The controller is programmed to adjust a closed-state torque capacity of the bypass clutch according and in proportion to the greater in absolute value of a negative impeller torque command to the torque converter and a negative regenerative braking torque request.

A hybrid vehicle includes an engine, an electric machine selectively coupled to the engine, a transmission having a torque converter impeller coupled to the electric machine and a torque converter clutch configured to selectively couple the impeller to a turbine, and a controller configured to control pressure of the torque converter clutch responsive to estimated clutch capacity, which is adjusted by the controller to equal impeller torque responsive to impeller speed exceeding turbine speed during clutch disengagement. A model of estimated torque converter clutch capacity may be stored in memory and adapted to actual clutch capacity by applying a gain or offset determined during opening of the clutch.

A method of controlling a hybrid vehicle in case of slip of a Mild Hybrid Starter Generator (MHSG) drive belt is disclosed. The method may include determining an amount of torque assistance or an amount of regenerative braking according to the MHSG while the vehicle travels; instructing the MHSG to output a desired amount of torque, based on the amount of torque assistance or the amount of regenerative braking; detecting an output torque from the MHSG to compare the output torque with the desired amount of torque; and determining that slip occurs in the MHSG drive belt when a difference between the actual torque and the desired amount of torque exceeds a preference value, and performing control for slip prevention.

Disclosed herein is a technique for improving drivability of a vehicle by controlling the driving of the vehicle by a double clutch when the clutch of a double clutch transmission (DCT) is overheated. There is provided a shift control method for a hybrid vehicle with a DCT. In particular, where it is desired to perform shifting when one of clutches of the DCT is overheated, double-clutch shifting is performed using a non-overheated clutch and an engine clutch without using the overheated clutch, thereby reducing disharmonic shifting in virtue of a small difference in gear ratio during shifting and improving shifting and driving performance.