Abstract:
The invention relates to a motor vehicle comprising a water circuit for cooling its internal combustion engine, wherein the water circuit comprises an electrically operated engine fan and the engine fan is assigned a linear regulator which is thermally coupled to the water circuit.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to German Patent Application No. 102007023407.6, filed May 17, 2007, which is incorporated herein by reference in its entirety. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a motor vehicle, in particular, a passenger vehicle, comprising an engine fan for cooling an internal combustion engine. The voltage of the engine fan is regulated by a cooled linear regulator. 
       BACKGROUND 
       [0003]    The internal combustion engine of a motor vehicle is cooled by a water circuit which includes an engine fan. The engine fan is driven either electrically or mechanically when the engine is running. When the engine stops, there is generally some after-running of the then electrically-operated engine fan at a corresponding engine temperature. 
         [0004]    The engine fan has an electric motor whose power can usually be regulated in steps. In practice, the power regulation is effected by means of parallel or series switches or relays. In top-of-the range vehicles continuous regulation using regulators based on pulse width modulation, so-called PWM regulators, is also known. The PWM regulators accordingly function in the engine compartment with its frequently very high temperatures. 
         [0005]    US 2003/0058617 A1 describes a linear regulator for regulating the speed of the fan of an air-conditioning system in a passenger vehicle. Since the temperatures in the interior of the vehicle are generally significantly more moderate than in the engine compartment, it is sufficient in US 2003/0058617 A1 if the linear regulator is placed for its cooling in the air stream of the air-conditioning system and in this case, for example, also close to the rotor blades of the fan. Similar applications of the linear regulator for air-conditioning systems are also disclosed in US 2005/0264253 and EP 1475884 A2. 
         [0006]    It is an object of one embodiment of the invention to provide a motor vehicle with a continuously regulatable engine fan, whose regulation provides good electromagnetic compatibility at low costs. 
       SUMMARY OF THE INVENTION 
       [0007]    In a first embodiment, a motor vehicle comprising a water circuit for cooling its internal combustion engine is proposed. The water circuit comprises an electrically operated engine fan to which a linear regulator is assigned, i.e. the voltage of the engine fan is regulated by the linear regulator. The linear regulator is thermally coupled to the water circuit. 
         [0008]    The proposed solution makes it possible to continuously regulate the engine fan due to the linear regulator. The continuous regulatability initially results in a minimal development of noise with minimal loading of the battery. Compared with regulation by means of relays, a higher reliability is achieved due to fewer electrical connections, fewer cables and, due to the provision of overheating protection, fewer failures with a lower fire risk. The use of a linear regulator instead of relays also results in an approximately 50% reduced weight with an at least 80% smaller space requirement at less than half the price. Furthermore, the assembly costs are lower and diagnosis is feasible in the event of faults. 
         [0009]    Compared with PWM regulators, the linear regulator has a significantly better electromagnetic compatibility since said PWM regulators are disadvantageously clocked at 20 kHz. The PWM regulator therefore requires comprehensive measures to ensure electromagnetic compatibility which makes the PWM regulator a component which is nowadays about three times as expensive as a linear regulator. The solution allows continuous regulation of the engine fan in small and medium-class vehicles for the first time at acceptable prices but in return requires intervention in the complex cooling system of the internal combustion engine by removing the power loss of the linear regulator to the water circuit. 
         [0010]    In a second embodiment, the linear regulator is in thermal contact with a water line of the water circuit. When designing the vehicle, this makes it possible to select a position of the linear regulator close to the engine fan in order to also reduce the cabling expenditure. 
         [0011]    In a third embodiment, the water line has a recess into which the linear regulator or a cooling block assigned to the linear regulator is partially recessed. The water line consists, for example, of aluminium die casting, the linear regulator or its cooling block being recessed into the recess thereof and correspondingly sealed. The linear regulator is thus thermally coupled to the cooling liquid of the water circuit which is more efficient than cooling by means of air as the medium. 
         [0012]    In a further embodiment, the linear regulator is in thermal contact with a cooler which is assigned to the water circuit and contains the cooling liquid. For this purpose, the linear regulator can rest directly on the (water) cooler. 
         [0013]    In a further embodiment, the linear regulator is disposed in the air stream of the engine fan. In this respect, air cooling is carried out, the intervention in said water cooling circuit being minimal. 
         [0014]    A further aspect of the invention relates to a water cooler which is configured for detachable connection to a linear regulator, wherein the linear regulator serves to regulate the engine fan. The water cooler can be prepared in this respect in that the linear regulator is let into the water cooler or is fastened thereto by means of a clip connection. By this means, assembly of the components in the engine compartment is simpler, assembly time is saved, the components can be arranged more compactly and as a result, a greater freedom is obtained in the development of a new vehicle. 
         [0015]    One embodiment of the water cooler has a linear regulator connected detachably thereto. In this water cooler/linear regulator unit, the amount of pre-assembly is even greater and likewise the cost saving thereby achieved. The linear regulator can also be mounted on one of the lateral coolant end tanks of the water cooler. The coolant-outlet-side end tanks is preferably selected in this case because of the lower temperatures of the coolant. 
         [0016]    A further aspect of the invention relates to a CRFM module comprising a engine fan and a water cooler as described above. As a result of the functional integration which has been made, a smaller space requirement for the components in the engine compartment is also obtained here with a greater freedom in the development of a new vehicle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
           [0018]      FIG. 1  shows a motor vehicle in plan view; 
           [0019]      FIG. 2  shows a water cooler in side view; and 
           [0020]      FIG. 3  shows a water line for the water circuit with let-in linear regulator. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description. 
         [0022]    In the figures, which generally designate the same objects with the same reference numerals,  FIG. 1  shows a motor vehicle  1  in plan view. The motor vehicle  1  has an internal combustion engine  2 , the water cooler  3  and the air-conditioning condenser  4  being located in front thereof. An engine fan  5  is provided for after-running of the cooler after the motor vehicle  1  has stopped. 
         [0023]    Water cooler  3 , air-conditioning condenser  4  and engine fan  5  can be individual components for the separate cooling circuits or components of a CFRM module (condenser radiator fan module)  6  as indicated by the dashed line. The CRFM module  6  cools the internal combustion engine  2  in a known manner with cooling liquid  7  via the water line  7 . 
         [0024]    A linear regulator  8  is let into the water line  7 . The linear regulator  8  is connected via an electrical line  9  to the CRFM module  6  and continuously regulates its fan or engine fan  5 . This reduces the fan noise during after-running and also the loading of the battery (not shown) to a minimum at low costs and in an EMC-compatible manner. Despite the high temperatures at times in the engine compartment, this is achieved with the linear regulator  8  which can be sufficiently cooled by the cooling liquid in the water circuit. 
         [0025]      FIG. 2  shows a water cooler  3  with a linear regulator  8  screwed tightly onto an end tank  12 ,  13 . Since the coolant inlet  13  is on the right in  FIG. 2  and the coolant outlet  14  is on the right, the end tank  12  on the coolant outlet side is selected for this purpose because of the lower temperatures. The water cooler has a recess (not shown) matched to the dimensions of the linear regulator  8  which partially accommodates the linear regulator. The water cooler  3  can be part of the CRFM module  6  in  FIG. 2 . 
         [0026]      FIG. 3  shows the water line  7  for the water circuit for the internal combustion engine  2 . This has a recess  10  in which the cooling block  11  of the linear regulator  8  is embedded so that cooling liquid of the water circuit flows directly therearound. 
         [0027]    Although a specific embodiment has been described hereabove, the person skilled in the art will recognise that the description of this embodiment is not intended to restrict the invention in the given form. The invention should rather comprise all modifications, equivalents and alternatives which come within the scope of protection of the claimed invention. 
         [0028]    While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.