A transmission includes an input shaft coupled to a prime mover, a countershaft, main shaft, and an output shaft, with gears between the countershaft and the main shaft. A shift actuator selectively couples the input shaft to the main shaft by rotatably coupling gears between the countershaft and the main shaft. The shift actuator is mounted on an exterior wall of a housing including the countershaft and the main shaft. An integrated actuator housing includes a single external power access for the shift actuator. A controller interprets a shaft displacement angle, determines if the transmission is in an imminent zero or zero torque region, and performs a transmission operation in response to the transmission in the imminent zero or zero torque region.

A hydraulic control system for a transmission is provided with a power source, two drive wheels, a power transmission device, a hydraulic pump, a main valve, and a controller. The power transmission device is configured to be set to a plurality of speed stages. The main valve is disposed between the hydraulic pump and the power transmission device and adjusts the main pressure of hydraulic fluid supplied from the hydraulic pump to the power transmission device. The controller controls the main valve. The controller sets the main pressure to a pressure value derived by correcting a clutch holding pressure of the set speed stage based on a load applied to each of the drive wheels.

A method for performing rotational speed synchronisation of a first transmission component having a first initial rotational speed with a second transmission component having a second initial rotational speed, so that they rotate with the same final rotational speed during a gear switch from an initial driving gear to a final driving gear in a stepped gear transmission for a hybrid electric or electric drive train having an electric traction motor. The method including calculating a total frictional work resulting from performing the total rotational speed synchronisation by means of a mechanical synchroniser of the stepped gear transmission only, and if the calculated total frictional work exceeds a maximal frictional work of the mechanical synchroniser, performing the rotational speed synchronisation by means of both the electric traction motor and the mechanical synchroniser.

Methods and system are described for changing a driveline gear range from a higher gear range to a lower gear range. The driveline may include two electric machines and four clutches in a four wheel drive configuration. The methods and systems permit a driveline to change from a higher gear range to a lower gear range without stopping a vehicle.

A method of determining a commanded friction brake torque is disclosed. The method uses inputs, such as from a gearshift sensor, an accelerator pedal sensor, a brake pedal sensor, and engine torque output sensor, a transmission speed input sensor and a transmission speed output sensor, to determine how much engine braking or regenerative braking is occurring. The method then uses this information combined with the braking command information from the brake pedal sensor to determine the amount of friction braking to apply to the friction brakes.

A transmission includes an input shaft and an output shaft, the input shaft selectively accepting a torque input from a prime mover, and the output shaft selectively providing torque output to a driveline. A controller determines a shaft displacement angle representing an angle value of rotational displacement difference between at least two shafts of the transmission, and performs a transmission operation responsive to the shaft displacement angle.

A method for performing rotational speed synchronisation of a first transmission component having a first initial rotational speed with a second transmission component having a second initial rotational speed, so that they rotate with the same final rotational speed during a gear switch from an initial driving gear to a final driving gear in a stepped gear transmission for a hybrid electric or electric drive train having an electric traction motor. The method including calculating a total frictional work resulting from performing the total rotational speed synchronisation by means of a mechanical synchroniser of the stepped gear transmission only, and if the calculated total frictional work exceeds a maximal frictional work of the mechanical synchroniser, performing the rotational speed synchronisation by means of both the electric traction motor and the mechanical synchroniser.

A method for operating a power shiftable transmission of a motor vehicle, the transmission including a control unit, an input shaft, an output shaft, a gear set, and multiple shift elements, the method including transmitting, with the control unit, a request for a reduction of a drive torque acting on the input shaft for carrying out an upshift, and determining, with the control unit, whether the reduction is completely possible, partially possible, or impossible based on a signal. When the reduction is completely possible, the method includes controlling, with the control unit, a torque transmission rate of a shift element of the multiple shift elements to be engaged during the upshift according to a first way. When the reduction is partially possible or impossible, the method includes controlling, with the control unit, the torque transmission rate according to a second way, the second way differing from the first way.

Methods and systems for estimating an amount of torque that is transferred via a differential ring gear assembly are described. In one example, axial displacement of the differential ring gear assembly is determined and converted into a torque estimate. The torque estimate may be used to verify other powertrain torque estimates or for closed loop torque control.

A vehicle includes a drive wheel, an engine, an accelerator pedal, a torque converter, a clutch, and a controller. The drive wheel is configured to propel the vehicle. The engine is configured to generate power and to deliver power to the drive wheel to accelerate the vehicle. The accelerator pedal is configured to generate an acceleration request based on a pedal position. The torque converter is disposed between the engine and the drive wheel. The clutch is disposed between the engine and the drive wheel and is configured to bypass the torque converter. The controller is programmed to, in response to depressing the accelerator pedal to a position that corresponds with accelerating the vehicle at a desired magnitude, adjust the torque of the engine to accelerate the vehicle at the desired magnitude, regardless of the state of the clutch.