Daimler Ag

Daimler Chrysler Ag

Michael Timmann

Hans Braun

Jochen Weeber

Ralf Körber

The invention relates to a cooling system in which the fan output is determined by an output control from the characteristic curves of the fan motor, the operating parameters of the cooling system and the reference input variables predetermined in the form of temperature levels. Different characteristic curves for the activation of the fan motor are here assigned to the different set temperature levels. If the reference input variable for the control changes, this also results in a change of the characteristic curves for activation of the fan motor. In order to prevent the fan motor starting to howl, in the event of a change in the reference input variable for the fan control the operation of the fan motor is kept constant for an adjustable minimum waiting time. During this minimum waiting time, switching over of the cooling circuit may have caused the operating parameters of the cooling system to adjust to the new reference input variable to such a degree that howling of the fan motor is no longer of concern.

Cooling system for an internal combustion engine of a motor vehicle

The invention relates to a method for actuating the valves in the three-way thermostat and in the heating cut-off valve of a cooling system. The valve setting in the cooling system is in this case selected such that during the warm-up phase of the engine, until the latter has reached its operating temperature, the coolant in the cooling ducts is brought to rest until the coolant temperature exceeds a predefined reference value.

Method for adjusting a coolant flow by means of a heating cut-off valve

The present invention relates to control of a fan during which the power of the fan is determined from the characteristic curves of the fan motor, the operating parameters of the cooling system and the reference variables which are predefined in the form of temperature levels. The various temperature levels which are to be set have different associated characteristic curves for actuating the fan motor. If the reference variable for the control changes, this also means a change in the characteristic curves for actuating the fan motor. In order to prevent the fan motor from whining, the operation of the fan motor is kept constant for a settable minimum waiting time when the reference variable for the control of the fan changes. During this minimum waiting time, the operating parameters of the cooling system can, if appropriate, be adapted by means of other control mechanisms which are independent of the fan to the new reference variable to such an extent that it is no longer necessary to take measures with respect to the whining of the fan motor.

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Eutingen, Germany

Michael Timmann