A method is provided to start a combustion engine in a hybrid powertrain, comprising a gearbox with input and output shafts; a first planetary gear, connected to the input shaft and a first main shaft; a second planetary gear connected to the first planetary gear and a second main shaft; first and second electrical machines respectively connected to the first and second planetary gears; one gear pair connected with the first main shaft, and therefore with the first planetary gear and the output shaft; and one gear pair connected with the second main shaft. The method comprises: a) connecting an output shaft of the combustion engine with the input shaft of the gearbox, via a coupling device arranged between the output shaft and the input shaft; and b) controlling the first and second electrical machines to start the combustion engine.

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.

Systems and methods for operating a driveline of a hybrid vehicle are presented. In one example, the systems and methods determine a driveline disconnect boost time during vehicle operating conditions when it may be less noticeable. The driveline disconnect boost time may then be used to close a driveline disconnect clutch in a way that may reduce torque disturbances through the driveline.

According to one embodiment of this disclosure, a vehicle having an electric machine and at least one controller is described. The electric machine may be configured to generate creep torque to move the vehicle. The controller may be programmed to decrease a target speed of a torque converter impeller to create a desired brake torque and partially cancel the creep torque without application of friction brakes in response to a brake pedal being pressed while an accelerator pedal is not being pressed.

A system and method are provided for hybrid electric internal combustion engine applications in which a motor-generator, a narrow switchable coupling and a torque transfer unit therebetween are arranged and positioned in the constrained environment at the front of an engine in applications such as commercial vehicles, off-road vehicles and stationary engine installations. The motor-generator is preferably positioned laterally offset from the switchable coupling, which is co-axially-arranged with the front end of the engine crankshaft. The switchable coupling is an integrated unit in which a crankshaft vibration damper, an engine accessory drive pulley and a disengageable clutch overlap such that the axial depth of the clutch-pulley-damper unit is nearly the same as a conventional belt drive pulley and engine damper. The front end motor-generator system includes an electrical energy store that receives electrical energy generated by the motor-generator when the coupling is engaged. When the coupling is disengaged, the motor-generator may drive the pulley portion of the clutch-pulley-damper to drive the engine accessories using energy returned from the energy store, independent of the engine crankshaft.

A vehicle includes an engine, an automatic transmission, a second clutch for engine disconnection, a rotating electric machine, a first clutch for rotating electric machine separation, and an electronic control unit. The electronic control unit switches the first clutch from a release state to an engagement state in a case where a collision of the vehicle occurs, the first clutch is in the release state, and a rotation speed of the rotating electric machine is higher than an input shaft rotation speed of the automatic transmission. In a case where the collision of the vehicle occurs, the first clutch is in the release state, and the rotation speed of the rotating electric machine is lower than the input shaft rotation speed of the automatic transmission, the first clutch is maintained in the release state.

A threshold that is used in determining, based on a deviation between slip amounts, whether to stop slip control or not during the performance of feedback control in slip control is made smaller when pitch damping control is being performed than when pitch damping control is not being performed, during the performance of slip control of a lockup clutch. Therefore, slip control is likely to be stopped when the torque input to the lockup clutch is likely to fluctuate. In consequence, a control apparatus and a control method for a vehicle that make it possible to stably perform slip control of the lockup clutch while increasing the number of opportunities to perform the slip control and pitch damping control are provided.

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 control system controls a power transmission system located between a motive power source and drive wheels. The power transmission system includes a fluid coupling and an engagement device. The control system includes an electronic control unit configured to: obtain information concerning vibration of the power transmission system; determine whether the vibration of the power transmission system is in a resonance region of the power transmission system; control the engagement device so that the engagement device slips, when the electronic control unit determines that the power transmission system is in the resonance region; and control the motive power source when the electronic control unit determines that the power transmission system is in the resonance region, so that a rotational speed of the motive power source increases as compared with a case where the power transmission system is not in the resonance region.

A power transmission system includes first differential mechanism connected to an engine, and second differential mechanism. The first differential mechanism includes a first rotating element connected to the engine, and second and third rotating elements. The second differential mechanism includes a fourth rotating element connected to second rotating element, fifth rotating element connected to a first electric rotary machine, and sixth rotating element that is an output element of the second differential mechanism. The power transmission system further includes at least one of a first clutch and brake, and a second clutch. The first clutch is configured to releasably couple two of the first, second and third rotating elements to each other. The brake is configured to releasably couple the third rotating element to a stationary element. The second clutch is configured to releasably couple the third rotating element to one of the fifth and sixth rotating elements.