Method and apparatus for setting a setpoint output voltage of a generator which is disposed in a motor vehicle

1 . A method for setting a setpoint output voltage of a generator disposed in a motor vehicle, which comprises the steps of:

lowering the setpoint output voltage of the generator if the setpoint output voltage exceeds a prespecified first threshold value and if an actuation signal for a fan for cooling a motor of the motor vehicle reaches or exceeds a second threshold value.

2 . The method according to claim 1 , which further comprises:

determining an external temperature; and

lowering the setpoint output voltage only if the external temperature reaches or exceeds a prespecified third threshold value.

3 . The method according to claim 1 , which further comprises lowering the setpoint output voltage only if, as it rises, the actuation signal for the fan reaches or exceeds the second threshold value.

4 . The method according to claim 1 , which further comprises lowering the setpoint output voltage for a prespecified first time period.

5 . The method according to claim 1 , which further comprises:

determining a pressure of a refrigerant for an air-conditioning device of the motor vehicle; and

lowering the setpoint output voltage if the pressure determined reaches or exceeds a prespecified fourth threshold value.

6 . The method according to claim 5 , which further comprises lowering the setpoint output voltage until the pressure of the refrigerant reaches or falls below a prespecified fifth threshold value.

7 . The method according to claim 6 , which further comprises setting the fifth threshold value to be lower than the fourth threshold value.

8 . The method according to claim 5 , which further comprises determining a second time period during which the setpoint output voltage is lowered as a function of the pressure determined.

9 . The method according to claim 1 , which further comprises adding up times during which the setpoint output voltage of the generator is lowered and a charging period for charging a battery of the motor vehicle is extended as a function of the added times.

10 . The method according to claim 1 , which further comprises lowering the setpoint output voltage of the generator to the first threshold value.

11 . An apparatus for setting a setpoint output voltage of a generator disposed in a motor vehicle, the apparatus comprising:

a control device configured for lowering the setpoint output voltage of the generator if the setpoint output voltage exceeds a prespecified first threshold value and, in addition, if an actuation signal for a fan for cooling a motor of the motor vehicle reaches or exceeds a second threshold value.