Patent ID: 6932737

Claim:
A control unit for setting a transmission ratio of a transmission which is arranged in a drive tram together with an engine and an electric generator, in order to obtain braking assistance through a braking torque of the engine, and to bring about a braking torque of the electrical generator, the generator feeding a battery, said unit comprising a plurality of signal inputs for receiving a desired braking torque and a rotational speed of the engine and/or a speed of the vehicle, a comparator unit for comparing the rotational speed of the engine and/or the vehicle speed with switching points of the transmission, each switching point corresponding to a rotational speed of the engine or to a vehicle speed, and for determining the transmission ratio of the transmission suitable for achieving the desired braking torque, a signal output for outputting a control signal which determines the transmission ratio of the transmission, and a calculation unit for determining the switching points of the transmission as a function of a charge status of the battery wherein the switching points for a partially discharged battery are less than the corresponding switching points for a fully charted battery.