Fan Module and Method for Operating the Same

This application claims the priority, under 35 U.S.C. § 119, of German Patent Application DE 10 2024 203 346.4, filed Apr. 11, 2024; the prior application is herewith incorporated by reference in its entirety.

The invention relates to a fan module and to a method for operating the same.

A motor vehicle typically has a radiator by means of which a coolant in an engine cooling circuit can be cooled. When the motor vehicle has an air conditioning system, the system comprises a condenser by means of which a refrigerant for an air conditioning circuit is cooled.

In order to cool the radiator and/or the condenser, a fan module is used to generate a cooling air flow.

The fan is typically mounted in an engine compartment or in a wheel arch of the vehicle. In particular, if the vehicle is used on dirty roads or off-road, there is a risk of the fan module, the radiator, and/or the condenser becoming dirty. This can disadvantageously lead to reduced cooling performance or even a blockage of the fan wheel of the fan module.

A fan assembly is known from published patent application US 2016/047609 A1 which is designed for automatic cleaning of its heat exchanger or air filter. Cleaning involves temporarily reversing the direction of a fan in the fan assembly to reverse the airflow through the heat exchanger or air filter for the purpose of removing dust, dirt, and other contaminants.

It is accordingly an object of the invention to provide a method and a fan module which overcome a variety of disadvantages associated with the heretofore-known devices and methods of this general type and which provides for an especially suitable method for operating a fan module. In particular, the aim is to enable the removal of contamination from the fan module and/or a heat exchanger that is to be cooled by the same. Furthermore, such a fan module as well as a device with such a fan module and with a heat exchanger are to be specified.

With the above and other objects in view there is provided, in accordance with the invention, a method for operating a fan module, which has a fan wheel and a motor for driving the fan wheel. The method comprises:

The method is used to operate a fan module. The fan module is intended and configured to cool at least one heat exchanger, in particular a radiator and/or a condenser. In particular, the fan module is intended and configured for use in a motor vehicle.

The fan module is also designated as a CFM (cooling fan module).

The fan module comprises a fan wheel. The fan wheel serves to generate an air flow in order to cool the heat exchanger as it rotates. Furthermore, the fan module comprises a motor, expediently an electric motor, for the fan wheel, i.e., for driving the fan wheel in rotation.

According to the method, the motor is operated in a cleaning mode to loosen contamination from the fan wheel and/or heat exchanger, i.e., in order to remove the contamination. In the cleaning operating mode, the motor is operated at a predetermined cleaning speed (cleaning revolutions per minute, cleaning rpm), the cleaning speed being greater than the rated speed of the motor, in particular for and/or when cooling the heat exchanger.

Due to the rotation of the motor and the associated fan wheel at the cleaning speed, and/or when the fan wheel accelerates to the cleaning speed, the fan wheel and/or a fan shroud coupled to the fan wheel vibrates. This is caused particularly by an imbalance of the fan wheel due to contamination and/or design-related factors, such as tolerances. Due to this vibration, and/or due to the comparatively high speed of the fan wheel, dirt and/or water is removed from the fan wheel and/or from the fan shroud, in particular shaken off, or this is at least made easier.

Furthermore, the air flow is stronger due to the comparatively fast rotation of the fan wheel, so that any dirt is carried along and removed from the respective heat exchanger by the air flow.

It is expedient that the direction of rotation of the motor and/or fan wheel be the same during the cleaning operating mode as during cooling of the heat exchanger, i.e., that it be the same as in a cooling operating mode.

The rated speed can and/or is expediently understood to mean the speed of the motor at which the motor delivers the nominal power, in particular the maximum power that is intended for continuous operation.

In particular, in cooling mode—i.e., for cooling the respective heat exchanger—the motor is operated at a speed that is less than or equal to the rated speed.

According to one expedient embodiment, the cleaning speed is between 1.5 times and 10 times, in particular between 1.5 times and 5 times, preferably between 2 times and 4 times, for example 3 times the rated speed.

This effects a comparatively strong vibration of the fan wheel and/or fan shroud and/or a comparatively strong air flow for the respective heat exchanger. The cleaning is therefore comparatively reliable.

The cleaning speed is expediently selected in such a way that damage to the fan module and/or the heat exchanger is avoided.

According to one suitable embodiment, the fan wheel is driven at the cleaning speed for a time period between 1 s (second) and 30 s, in particular between 1 s and 10 s. In other words, the cleaning mode continues for this time period. It is expedient to then terminate the cleaning operating mode and/or reduce the motor speed to a speed that is less than or equal to the rated speed. This time limitation makes it possible to prevent damage to the fan module due to vibration and/or comparatively severe wear of the fan module or to at least reduce the risk of this.

According to an advantageous embodiment of the method, the cleaning operating mode is started when off-road operation of the motor vehicle is terminated.

The cleaning operating mode is started in particular and/or preferably automatically when and/or as soon as a signal representing the termination of off-road operation is received from a control device for the motor. In particular, the cleaning operating mode is started as a result of this signal.

The signal is fed to the control device from a control unit that is external to the fan module or from a sensor, for example.

The fan module and/or the heat exchanger can thus be advantageously cleaned after driving off-road, when the fan module is typically dirtied relatively heavily and/or is relatively likely to become dirty. It is in this way that an especially suitable time for the cleaning operating mode is chosen.

Another aspect of the invention relates to a fan module. It is expedient for this to be operable according to the method in one of the variants described above and/or to be operated according to the method.

The fan module comprises—as described in connection with the method—the fan wheel and a motor, in particular an electric motor, for driving the fan wheel. For this purpose, the fan wheel is coupled in a rotationally fixed manner to the motor.

The fan module expediently further comprises a shroud to which the motor is attached and/or which is provided and configured for attachment to the heat exchanger.

Furthermore, the fan module comprises a control unit for carrying out the method according to any one of the method variants described above. The control unit is, or comprises, the (motor) control unit for the motor.

The control unit is therefore designed to control the motor in such a way that it is operated in a cleaning operating mode at a cleaning speed which is greater than the rated speed.

The rated speed and/or the cleaning speed are expediently stored in a memory of the control unit.

The motor is expediently attached to the fan shroud, which will also be referred to simply as the shroud below. The shroud is also designed to be attached to and/or in the vicinity of the heat exchanger. The shroud comprises a fan wheel recess, i.e., a material recess within the fan shroud, whereby the fan wheel is rotatably held in the fan wheel recess.

The fan wheel recess is limited by a shroud ring in a plane that is oriented perpendicular to the axis of rotation of the fan wheel and/or which is the main plane of extension of the shroud. For example, the shroud ring is formed by an edge of the fan wheel recess. Furthermore, for example, the shroud ring is formed by a wall, in particular a hollow cylindrical wall, extending in a direction parallel to the axis of rotation of the fan wheel.

According to a preferred embodiment, the fan shroud comprises a drain hole for dirt released from the fan wheel. Preferably, the drain hole is arranged at least partially in the shroud ring of the fan shroud. Preferably, the drain hole is arranged radially outside the fan wheel.

The drain hole is preferably continuous in a (radial) direction perpendicular to the axis of rotation. Additionally or alternatively, the drain hole is arranged in the vicinity of the shroud which, in the intended installed state, is arranged at the bottom, i.e., facing toward a substructure.

By virtue of the drain hole and/or the arrangement thereof, it is advantageously easier for dirt to flow away from the fan module and/or to prevent blockage of the fan wheel as a result of protective particles accumulating between the fan wheel and the shroud.

According to one especially suitable embodiment of the fan module, the fan wheel and/or the fan shroud has an additive to increase the smoothness of its surface. In other words, the material, in particular plastic, of the fan wheel and/or the fan shroud comprises this additive. The additive is used to reduce the roughness of the surface of the fan wheel and/or fan shroud.

By virtue of this comparatively smooth surface, the adhesion of dirt to this surface is reduced and/or the dirt is easier to remove.

For example, polyamide and/or polypropylene are used as the (base) material for the fan wheel and/or fan shroud. Silicon dioxide, particularly synthetic, natural, and/or mineral silicon dioxide, is advantageously used as an additive.

Another aspect of the invention relates to a device, particularly for a motor vehicle. The device comprises at least one heat exchanger. For example, the heat exchanger is a radiator for engine cooling of the motor vehicle or a condenser for an air conditioning system of the motor vehicle.

For example, the device comprises both a radiator as a (first) heat exchanger and a condenser as a (second) heat exchanger.

Furthermore, the device comprises a fan module which is embodied in one of the fan module variants described above and/or is operable and/or operated according to any one of the method variants described above.

The fan module is designed and configured to cool the heat exchanger by causing an air flow through and/or onto the heat exchanger.

The fan module is expediently arranged and/or attached to the heat exchanger.

For example, the device is embodied as a so-called CRFM (Condenser/Radiator/Fan Module).

Other features which are considered as characteristic for the invention are set forth in the appended claims.

It should also be noted that all specifications and advantageous modifications described in connection with the general invention apply mutatis mutandis to the fan module and/or to the device and vice versa.

Although the invention is illustrated and described herein as embodied in a fan module and method for operating the same, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Analogous parts and variables are provided with the same reference symbols throughout the figures.