Method and Control Unit for Operating a Drive Train

Abstract

Method for operating a drive train, which features several drive units (1, 2), one transmission (3) and one output (4), whereas a first drive unit (1) acts on a first transmission shaft (6) of the transmission (3), whereas a second drive unit (2) acts on a second transmission shaft (7) of the transmission (3), whereas the transmission (3) comprises several shift elements (9), whereas, at the output (4), an output torque that depends on the torque required by the driver is provided, and whereas, for the opening of a shift element (9) of the transmission (3), the shift element (9) to be opened is positioned in a load-free manner. For the load-free positioning of the shift element (9) to be opened, target torques are calculated for the first drive unit (1) and the second drive unit (2), by means of which, while maintaining the torque required by the driver at the output, the shift element (9) to be opened can be positioned in a load-free manner, whereas there is an examination of whether at least one of such target torques violates the torque limit of the respective drive unit (1, 2), whereas, if it is then determined that neither of the target torques violates a torque limit of the respective drive unit (1, 2), the first and second drive unit (1, 2) is guided in a torque-controlled manner to the respective target torque while maintaining the torque required by the driver at the output (4), whereas, if it is then determined that at least one of the target torques violates a torque limit of the respective drive unit (1, 2), the shift element (9) to be opened is positioned in a load-free manner while providing an output torque that deviates from the torque required by the driver.

Dependencies are inferred from the claim text.