Drivetrain Having a Driveable Rear Axle and Having a Vehicle Transmission, Method for Operating Said Drivetrain, and Motor Vehicle Having Said Drivetrain

A drivetrain, for a motor vehicle, comprising:

• at least one electric drive engine configured for driving the motor vehicle;
• a drivable motor vehicle axle designed as a rear axle for transmitting drive forces of the at least one electric drive engine to a roadway surface;
• a vehicle transmission, which has at least one gear stage and is configured for transmitting drive forces in the direction of the drivable motor vehicle axle, wherein, in at least one operating mode of the drivetrain, said at least one gear stage is switchable by a transmission control unit and wherein, in addition to said at least one gear stage, the vehicle transmission is switchable by the transmission control unit to a neutral position in which a transmission output shaft rotates freely with respect to a transmission input shaft;
• and
• an E-motor control unit for controlling the electric drive engine, wherein the electric drive engine, by way of said E-motor control unit, is operatable at least in a motor operation mode and in a neutral mode, in which the electric drive engine rotates without torque,
• wherein
• the E-motor control unit and the transmission control unit are connected to one another by at least two control lines, which are configured for transmitting control commands between said control units, and
• a control command is transmittable from the E-motor control unit to the transmission control unit via at least one of said two control lines so that the transmission control unit shifts the vehicle transmission to the neutral position.

A method for controlling a drivetrain, wherein the drivetrain comprises:

• at least one electric drive engine configured for driving the motor vehicle;
• a drivable motor vehicle axle designed as a rear axle for transmitting drive forces of the at least one electric drive engine to a roadway surface;
• a vehicle transmission, which has at least one gear stage and is configured for transmitting drive forces in the direction of the drivable motor vehicle axle, wherein, in at least one operating mode of the drivetrain, said at least one gear stage is switchable by a transmission control unit and wherein, in addition to said at least one gear stage, the vehicle transmission is switchable by the transmission control unit to a neutral position in which a transmission output shaft rotates freely with respect to a transmission input shaft;
• and
• an E-motor control unit for controlling the electric drive engine, wherein the electric drive engine, by way of said E-motor control unit, is operatable at least in a motor operation mode and in a neutral mode, in which the electric drive engine rotates without torque, wherein the E-motor control unit and the transmission control unit are connected to one another by at least two control lines, which are configured for transmitting control commands between said control units,
• wherein the method comprises the steps of:
• monitoring at least one operating parameter of the vehicle transmission by at least one monitoring device, wherein a transmission fault is determined if a deviation of the monitored operating parameter from a set value is detected;
• and
• determining the transmission fault by the E-motor control unit, wherein the E-motor control unit outputs a control command to the transmission control unit via at least one of the two control lines so that the transmission control unit shifts the vehicle transmission to the neutral position.

A motor vehicle, comprising:

• a drivetrain comprising:
• at least one electric drive engine, which is configured for driving the motor vehicle;
• a drivable motor vehicle axle, which is designed as a rear axle and for transmitting drive forces of the at least one electric drive engine to a roadway surface;
• and
• a vehicle transmission, which has at least one gear stage and is configured for transmitting drive forces in the direction of the drivable motor vehicle axle, wherein, in at least one operating mode of the drivetrain, said at least one gear stage is switchable by a transmission control unit and wherein, in addition to said at least one gear stage, the vehicle transmission is switchable by the transmission control unit to a neutral position in which a transmission output shaft rotates freely with respect to a transmission input shaft;
• an E-motor control unit for controlling the electric drive engine, wherein the electric drive engine, by way of said E-motor control unit, is operatable at least in a motor operation mode and in a neutral mode, in which the electric drive engine rotates without torque,
• wherein
• the E-motor control unit and the transmission control unit are connected to one another by at least two control lines, which are configured for transmitting control commands between said control units, and
• a control command is transmittable from the E-motor control unit to the transmission control unit via at least one of these two control lines so that the transmission control unit shifts the vehicle transmission to the neutral position.