Shift control method for an automated range-change transmission

A control device for shift control of an auxiliary transmission of a motor vehicle, the control device comprising at least one receiving interface, which is configured to receive either a transmission temperature signal or an ambient temperature signal from a temperature sensor, and to receive input signals from drive train components, an evaluation unit, which is configured for determining a current transmission temperature or a current ambient temperature and comparing the current transmission temperature or the current ambient temperature to a defined threshold, and evaluating the received input signals or information of the received input signals, and a transmitter interface, for transmitting control signals to the drive train components, the control device being configured to activate shifting elements of individual groups of the auxiliary transmission to change a gear in the auxiliary transmission by changing a transmission ratio step of a multi-step main gearing while maintaining a currently engaged transmission ratio step in a two-step front-mounted group, if the current transmission fluid temperature signal or the current ambient temperature is lower than the defined threshold, and, the control device being configured to perform a gear change in the auxiliary transmission, while maintaining the currently engaged transmission ratio step in the two-step front-mounted group if the current transmission fluid temperature signal or the current ambient temperature is higher than the defined threshold and if a current driving resistance of the motor vehicle does not fall below a first set threshold and does not exceed a second set threshold.

A computer program product, stored on a computer-readable data medium, for performing a method of shift control of an automated auxiliary transmission, which is mounted in a drive train of a motor vehicle between a drive motor and a final drive and comprises at least one multi-step main gearing and one two-step front-mounted group upstream of the main gearing, and in which the main gearing is shiftable, via unsynchronized clutches, and the front-mounted group is shiftable, via synchronized clutches, the method including, determining either a current transmission fluid temperature or a current ambient temperature, comparing the determined current transmission fluid temperature or the current ambient temperature to a defined threshold, and if the determined current transmission fluid temperature or the determined current ambient temperature is lower than the defined threshold, changing a gear in the auxiliary transmission by changing a transmission ratio step of the main gearing while maintaining a currently engaged transmission ratio step in the front-mounted group, and if the determined current transmission fluid temperature or the determined current ambient temperature is higher that the defined threshold, determining a current driving resistance of the motor vehicle, comparing the current driving resistance to first and second set thresholds;

• and if the current driving resistance does not fall below the first set threshold and does not exceed the second set threshold, performing a gear change of the auxiliary transmission by changing the transmission ratio step of the main gearing while maintaining the currently engaged transmission ratio step in the front-mounted group,
• the computer program product being executed on a control device for the shift control of the auxiliary transmission of the motor vehicle, the control device having at least one receiving interface, which is configured to receive signals from drive train components, an evaluation unit, which is configured for evaluating the received input signals, or information of the received input signals, and a transmitter interface, for transmitting control signals to the drive train components, the control device being configured to activate shifting elements of individual groups of the auxiliary transmission to change the gear in the auxiliary transmission according to the method.