A method for operating a hybrid vehicle having a prime mover including an internal combustion engine and an electric machine, the vehicle further having a transmission connected between the prime mover and a driven end and including multiple shift elements, the vehicle further having a separating clutch connected between the internal combustion engine and the electric machine, and a starting component which is provided by a separate launch clutch or by a shift element of the transmission. The method includes monitoring a rotational speed of one of the internal combustion engine, the electric machine, the transmission, or the driven end during travel with the internal combustion engine running and the separating clutch engaged. The method further includes determining an increase in driving resistance, and decoupling the internal combustion engine when the monitored rotational speed falls below or reaches a first limiting value by disengaging the separating clutch.

A control method of a variable speed electric motor system, which includes an electric device and a planetary gear transmission device, the control method includes: a step of accepting an instruction for a number of rotations of an output shaft; a step of calculating a number of rotations of a variable speed electric motor based on the number of rotations of the output shaft; a step of determining whether the calculated number of rotations of the variable speed electric motor is in an uncontrollable range; and a step of performing uncontrollable speed range operation for repeatedly and alternately performing a forward direction minimum rotation number instruction for driving the variable speed electric motor at a minimum number of rotations in a forward direction, and a reverse direction minimum rotation number instruction for driving the variable speed electric motor at a minimum number of rotations in a reverse direction.

A method for allocating power between electric machines in a powertrain of an electric vehicle is described. The electric vehicle includes a gearbox having an input shaft and an output shaft configured to transmit a first torque to the wheels of the vehicle, a first electric machine having an output shaft coupled to the input shaft of the gearbox, and a second electric machine configured to supply a second torque to wheels of the vehicle. The method comprises: prior to a gear change of the first electric machine, allocating power to the first and second electric machines according to a first power ratio; in response of an intended gear change of the first electric machine, allocating power to the first and second electric machines according to a second power ratio.

Operating an electric drive machine includes neutralizing a transmission in the electric drive machine operating in a first range, determining suitability of the electric drive machine for operating the transmission in a second range, and calculating a target transmission input speed, based on a speed parameter indicative of a transmission output speed, and the determined suitability for operating in a second range. A speed of an electric drive motor is varied based on the target transmission input speed, and a second clutch engaged to operate the transmission in the second range based on the varied speed of the electric drive motor. Related apparatus and control logic is also disclosed.

The invention relates to a method for operating a vehicle drive train (1) comprising a prime mover (2), comprising a transmission (3), and comprising a driven end (4). A friction-locking shift element (10) is provided, the power transmission capacity of which is variable and, with the aid of which, at least a portion of the torque transmitted in the vehicle drive train (1) can be transmitted between a transmission output shaft (8) and an area (6) of the driven end (4). One shift-element half is operatively connected to the transmission output shaft (8) and the other shift-element half is operatively connected to the area (6) of the driven end (4). The rotational speed of the transmission output shaft (8) is determined as a function of the rotational speed in the area (6) of the driven end (4) and also as a function of the rotational speed of the prime mover (2) and the ratio currently engaged in the area of the transmission (3). In the event of a deviation between the rotational speed of the transmission output shaft (8) determined on the output end and the rotational speed of the transmission output shaft (8) determined on the transmission-input end, which is greater than or equal to a threshold value and/or an operating temperature in the area of the friction-locking shift element (10), which is greater than or equal to a limiting value, measures reducing loads of the friction-locking shift element (10) are initiated.

A transmission control system for a machine is disclosed. The transmission control system may determine whether engine speed regulation during gear shift is enabled or disabled for the machine. The transmission control system may select a speed threshold, for inhibiting a high speed directional shift of the machine, based on whether the engine speed regulation during gear shift is enabled or disabled for the machine. The transmission control system may compare a speed of the machine and the speed threshold, and may selectively inhibit the high speed directional shift for the machine based on comparing the speed of the machine and the speed threshold.

A method for operating a multispeed transmission in a motor vehicle, provided with planetary gearings which can be switched with four switching elements to different gear ratios, and which can be connected by input elements and output elements to a driven input shaft and to an output shaft. The reaction elements can be coupled or locked with a brake, wherein the four planetary gearings can be switched by two brakes and by three shifting clutches to eight forward gear ratios. In the higher gear ratios, at least one first shifting clutch is connected to produce a force flow in the transmission, and in the lower gear ratios, at least a second shifting clutch is connected to produce a force flow in the transmission.

A method performs shifts in a dog clutch element of a transmission system in a hybrid vehicle. The vehicle has an input shaft being connected to a crankshaft of an internal combustion engine, an output shaft being connected indirectly to driven wheels, an electric machine which is in engagement with the input shaft, and an automatic transmission connected between the input and output shafts. The transmission has a dog clutch element for the releasable coupling of two transmission elements. During a desired shifting of the dog clutch element, the torque of the input shaft is adapted via the electric machine, and therefore a reduced load prevails in the region of the dog clutch element and the latter can be disengaged, after which the internal combustion engine is set to a desired target rotational speed, and after which the dog clutch element is engaged when the target rotational speed is reached.

Desired is a control device for a vehicle drive apparatus capable of determining an engagement failure in an engagement device when shifting a transmission device to a neutral state and making the rotational speed of a driving force source reduced. In order to shift a transmission device from a state in which an object shift speed is established and the vehicle is traveling to a neutral state in which no shift speed is established in the transmission device (#02), when an object engagement device is disengaged while maintaining engagement of a non-object engagement device and the rotational speed of a driving force source (#04, #06) is made to be reduced, an engagement failure in the object engagement device (#02, #07) is determined based on a change in the rotational speed of an input member.

A method and device for operating a powertrain of a motor vehicle are provided, wherein the powertrain includes an internal combustion engine, a transmission and a friction clutch arranged there between in order to control a power flow between the internal combustion engine and the transmission. The method includes the steps of detecting clutch judder, analyzing clutch judder, and determining a type of clutch judder. Based on determined type of clutch judder the method further includes selecting a udder countermeasure from a number of predetermined judder countermeasures and executing selected judder countermeasure. Detected clutch judder can be taken care of in an efficient way and future clutch judder may be prevented.