Systems and methods for operating a vehicle that includes an engine and an electric machine are described. In one example, an actual total number of transmission gear downshifts are counted to determine whether or not a transmission clutch characterization is immature. The transmission clutch characterization may be adjusted if it is determined to be immature.

A vehicle control method is provided for controlling a vehicle in which a clutch provided on a power transmission path between an engine and a drive wheel is disconnected when a shift range is a non-driving range and the clutch is connected when the shift range is a driving range. The vehicle control method controls the engine to a prescribed idling speed, controls engine torque to a negative torque by delaying an ignition timing of the engine; and causes the prescribed idling speed to drop within a prescribed amount of time needed for the clutch to switch from being disconnected to being connected when the shift range is switched from the non-driving range to the driving range.

Systems and methods for operating a driveline of a hybrid vehicle are described. In one example, a torque that is produced by an engine is adjusted responsive to a transmission oil temperature and a speed of a torque converter impeller so that temperature of oil in a transmission lube circuit may be maintained at a desired temperature.

A vehicle includes a torque converter bypass clutch, a wheel, a generator, and a controller. The torque converter bypass clutch is disposed between the wheel and the electric machine. The controller is programmed to, responsive to slip of the clutch exceeding a threshold during regenerative braking, energize the electric machine such that a torque being transferred from the wheel to the electric machine increases at a first rate and increase clutch pressure to decrease the slip. The controller is further programmed to, responsive to the slip decreasing to less than the threshold during the regenerative braking, adjust electric machine energization such the that torque being transferred from the wheel to the electric machine increases at a second rate that is greater than the first rate.

A method for operating a hybrid vehicle that includes a prime mover (1) with an internal combustion engine (2), an electric machine (3), a transmission (4) connected between the prime mover (1) and a driven end (5), and multiple shift elements, including a separating clutch (7) connected between the internal combustion engine (2) and the electric machine (3), and a starting component (8), is provided. After release of a brake pedal (12) or together with the release of the brake pedal (12) for a driving start or an crawling start, an engagement speed threshold (22) for the starting component (8) is established below an idling speed of the prime mover (1) and a previously disengaged starting component (8) is engaged. A control unit (9, 10, 11) for carrying out such a method is also provided.

A method for operating a vehicle that includes a torque converter is described. In one example, the method adjusts torque of an electric machine in response to a requested torque converter speed. The requested torque converter speed linearizes torque output of a torque converter so that vehicle wheel torque control may be improved.

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 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 vehicle, in the drivetrain of which a clutch, in particular a wet-running multi-disc clutch, is connected as a starter element between an internal combustion engine and a transmission, having a clutch controller, which, as a function of current driving operation parameters, determines a setpoint clutch torque and actuates a clutch actuator with a manipulated variable correlating with the setpoint clutch torque, in order to set at the clutch an actual clutch torque, which manipulated variable is determined as a function of the setpoint clutch torque and of a coefficient of friction stored in the clutch controller in an actuation unit of the clutch controller, and having an engine controller, which determines an actual engine rotational speed and an actual engine torque, and, in a stationary state of the vehicle with the internal combustion engine running, regulates the actual engine rotational speed to a predefined idling rotational speed.

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.