Patent Publication Number: US-6908283-B2

Title: Vehicle fan shroud made integrally with a coolant reservoir

Description:
FIELD OF THE INVENTION 
     The present invention relates to automotive equipment, in particular to fan shrouds and specifically to a fan shroud made integrally with a coolant reservoir. 
     BACKGROUND OF THE INVENTION 
     For better understanding the principle of the present invention and for introducing terminology used in the description, it would be advantageous to briefly explain the structure and operation of the radiator and the radiator cooling system. 
     The radiator is a device designed to dissipate the heat, which the coolant has absorbed from the engine. It is constructed to hold a large amount of a cooling liquid or coolant in tubes or passages, which provide a large area in contact with the atmosphere. As the coolant passes through the radiator during operation of the engine, it loses its heat to the airstream, which passes around the outside of the tubes. Normally, the cooling system of a vehicle has a clear plastic container, which is also known as a coolant reservoir or a coolant overflow bottle (hereinafter referred to as coolant reservoir). The coolant reservoir has marked lines that indicate the upper and lower allowable levels of the coolant in the cooling system. This coolant reservoir is connected to the coolant supply tube, which is also known as a siphon tube from the radiator and provides extra storage space for the coolant when it expands. As the engine heats up, the coolant inside it expands. Without the coolant reservoir, the coolant would flow out of the overflow tube and be lost from the cooling system. 
     Since a vacuum is created in the cooling system when the engine cools, the vacuum causes some of the coolant in the coolant reservoir to be sucked back into the system. The suction is carried out through the aforementioned coolant supply tube. In known radiator cooling systems the coolant supply tube from the radiator is connected to the coolant reservoir through the wall of the reservoir in its upper part or through a coolant reservoir cap which is used for adding the coolant to the cooling system when necessary. The end of the coolant supply tube inserted into the reservoir extends down to the point close or below the indicator of the lower allowable level. 
     The coolant reservoir may also be provided with an overflow tube located close to the top of the reservoir, e.g., in the coolant filling neck, for the overflow of the coolant when it expends to the level above this overflow tube, and with a drain tube at the bottom of the reservoir for draining the coolant from the reservoir, e.g., for cleaning the interior of the reservoir. 
     Because a cooling system with the coolant reservoir is virtually a closed system, the coolant can flow between the system and the coolant reservoir as it expands and contracts. This way, no coolant is lost if the system is functioning properly. The advantage of the coolant reservoir is that while the level of coolant contained in it rises and falls, the radiator is always full. 
     The radiator is provided with a fan surrounded by a shroud. The fan cools the cooling liquid while it circulates through the radiator&#39;s channels. 
     There exist a variety of arrangements for placing the coolant reservoirs in the vicinity of the radiator. Normally the coolant reservoir is attached to a vehicle body in the engine compartment and is located separately from the radiator or shroud. However, some vehicle models have the coolant reservoir removably connected to the fan shroud. 
     For example, U.S. Pat. No. 6,523,507 provides a fan shroud for an internal combustion engine that includes a snap-on detachable overflow bottle. The fan shroud has a fan opening and a unitary bottle mount with a deflectable bottle clip with a latch end that engages a groove in the overflow bottle. The mount includes an opposite side with an inwardly directed locking surface that engages a recess in a side face of the overflow bottle. The overflow bottle is held upright and secured to the fan shroud by snapping it into the bottle mount. A disadvantage of the design disclosed in the aforementioned patent is that it requires the use of additional snapping fasteners that can get loose under the effect of vibrations that normally occurs in the engine compartment when the vehicle is running. As a result, the coolant reservoir will be subject to vibrations that will generate a noise. Another disadvantage of the device of U.S. Pat. No. 6,523,507 is that the coolant is supplied to the coolant reservoir through a separate coolant supply tube that is inserted into the reservoir through the sealing unit. In other words, the arrangement requires the use of additional parts, such as tubes, seals, snapping elements, etc., is complicated in the manufacture, and costly in production and assembling. 
     The authors of U.S. Pat. No. 6,523,507 criticize the construction of fan shrouds molded integrally with the coolant overflow bottles stating that in the case of puncture or other damage of the bottle the whole shroud has to be replaced. It is understood, however, that the coolant overflow bottle located in the engine compartment and protected by the vehicle hood will never be punctured unless the vehicle is seriously damaged in an accident. If this happens, the engine has to be removed from the vehicle anyway and the shroud has to be removed as well. 
     U.S. Pat. No. 5,971,062 discloses a fan shroud, which is made integrally with at least one chamber for storage of a liquid or with several chambers for storage of several liquids, which may be under pressure and used with a vehicle. To facilitate handling pressure, the storage chamber includes a plurality of individual storage modules which are interconnected by a plurality of fluid flow channels so that the total storage capacity of the chamber is the sum of the storage capacity of the modules and interconnecting fluid flow channels. The modules and channels are made by bringing the front and back walls of a blow molded fan shroud into contact with each other to define there between channels and modules. The shroud comprises several such chambers and may be used to house engine coolant, power steering fluid or other fluids. In addition, the fan shroud can include chambers for storing fluids, which are not necessarily under pressure such as windshield washer fluid and the like. 
     A disadvantage of the arrangement shown in U.S. Pat. No. 5,971,062 is that it has a very complicated construction, which is expensive to manufacture. There is no indication in the description of the above patent to the way of checking the level of the coolant in the coolant reservoir of the device of the invention. It can be assumed, however, that since the reservoir and the shroud are blow-molded as a single piece, they are made from the same material. The shroud is normally molded from a non-transparent material and therefore the level of the coolant in the coolant reservoir is presumably checked by opening the filling cap, which is inconvenient. 
     U.S. Pat. No. 6,189,492 describes an automotive fan shroud that is molded integrally with two compartments, one for the coolant and another for windshield washing liquid. The compartments are closed from above by separate covers through which liquids are supplied into the respective containers. Since the compartments are molded from the same nontransparent material as the shroud, the level of the liquids in the compartments cannot be observed unless the covers are removed. Furthermore, the use of additional tubes and covers that require means for securing them in place makes the construction expensive in manufacture and assembling. 
     Typical engine cooling systems of vehicles are shown in a series of Automotive Repair Manuals for vehicles of various models, which are available in many automotive parts stores. For example, a cooling system for Mitshubishi Pick-ups 1983 through 1996 and Mitsubishi Montero 1983 to 1993 (shown in page 3–4, Chapter 3 of the Mitsubishi Puck-ups &amp; Montero Automotive Repair Manual by Larry Warrenm et al. issued by Haynes Publishing Group) contains a coolant reservoir with a coolant supply tube and an overflow tube connected to the reservoir through a coolant filler cap. The reservoir is installed separately from the fan shroud. Such an arrangement entails all previously mentioned drawbacks, i.e., connection of the feeler tube and the overflow tube through seals and securing fasteners. The feeler cap has a complicated construction. The reservoir has to be attached to an internal part of the vehicle body inside the engine compartment with the use of additional fasteners which can get lose under the effect of shocks and vibrations to which a vehicle is normally subject during running. Location of the coolant reservoir separate from the shroud and the need for attachment with fasteners increases the cost of manufacturing and assembling. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a fan shroud made integrally with a coolant reservoir, which is simple in construction, inexpensive to manufacture, excludes a need for using fasteners, simplifies manufacturing and assembling procedures, reduces the number of parts required for the cooling system of the motor engine, reduces the number of manufacturing and assembling steps, and improves conditions for observation of the coolant level in the coolant reservoir. 
     The device of the invention comprises a substantially rectangular fan shroud produced by injection molding from a non-transparent plastic such as filled polypropylene and a transparent or semitransparent coolant reservoir thermally welded to one of the upper corners of the shroud flange on the face side of the shroud. The coolant reservoir is also produced by injection molding from such plastics as polypropylene or polyethylene. A distinguishing feature of the coolant reservoir of the invention is that it has a substantially triangular shape to match the configuration of the circular peripheral part of the hub portion of the shroud and is made in a box-like form with one side of the reservoir casing being open. This reservoir is closed by attaching it to the surface of the aforementioned flange portion of the shroud that thus forms one sidewall of the coolant reservoir. The outer periphery of the open side of the reservoir has a small weld flange for convenience of thermal welding and for forming a thermal weld seam along the outer side of the weld flange. Another distinguishing feature of the device of the invention is that the portion of the coolant supply tube, which in conventional coolant reservoirs is inserted into the reservoir via seals through the reservoir filler cap or through the upper part of the reservoir wall, a nipple portion of the coolant supply tube for connection to the hose from the radiator, and a drain pipe extended from the bottom of the reservoir, are molded integrally, e.g., as a single piece with the reservoir casing. All three tubular portions are arranged coaxially and formed in the inner corner part of the coolant reservoir on the side opposite to the aforementioned open side of the molded reservoir. The coolant supply tube portion, which is located inside the reservoir, extends downward below the lower allowable level indication mark and close to the reservoir bottom. In its upper part, the reservoir is also provided with a reservoir filler cap. The overflow pipe of the reservoir that extends outward from the reservoir can be molded integrally with the neck portion of the reservoir. A coolant reservoir cap closes the opening of the neck portion by being snugly fit and snapped on the neck portion. In order to prevent the loss of the cap, it can be connected to the reservoir by a flexible cord. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a general front view of the fan shroud made integrally with a coolant reservoir in accordance with the present invention, the view being seen from the front side of the vehicle. 
         FIG. 2  is a three-dimensional view of the coolant reservoir obtained from an injection molding machine, the view being seen looking at the open side of the reservoir. 
         FIG. 3  is a top view of the coolant reservoir in the direction of arrow A in  FIG. 2 . 
         FIG. 4  is a sectional view along line IV—IV through a part of the reservoir illustrating position of the coolant supply tube. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The device of the invention comprises a fan shroud and a coolant reservoir assembly, which as a whole is designated by reference numeral  20  and is shown in  FIG. 1 , which is a front view of a fan shroud made integrally with a coolant reservoir of the present invention. The view of  FIG. 1  is seen from the front side of the vehicle (not shown). As can be seen from  FIG. 1 , the device  20  comprises a substantially rectangular fan shroud  22  produced by injection molding from a non-transparent plastic such as filled polypropylene and a transparent or semitransparent coolant reservoir  24  thermally welded to one of the upper corners of the substantially flat shroud flange  26  on the face side of the shroud  22 . The coolant reservoir  24  is also produced by injection molding from such plastics as polypropylene or polyethylene. A distinguishing feature of the coolant reservoir  24  of the invention is that it has a shape of irregular polygon to match the configuration of the circular peripheral part of the hub portion  28  of the shroud  22  and is made in a box-like configuration with one side of the reservoir casing being open. 
     The open side  29  of the coolant reservoir is shown in  FIG. 2 , which is a three-dimensional view of the coolant reservoir  24  after molding in an injection molding machine, the view being seen looking at the open side of the reservoir. 
     This reservoir  24  is closed by attaching it to the surface of the aforementioned flange portion  26  of the shroud  22  so that the surface of the flange  26  forms one sidewall of the coolant reservoir. As shown in  FIG. 2 , the outer periphery on the open side  29  of the reservoir has a thin weld flange  30  for convenience of attaching the coolant reservoir  24  to the surface of the flange  26  by thermal welding and for forming a thermal weld seam along the outer periphery of the weld flange  30 . The welding flange is clearly seen in  FIG. 3 , which is a top view of the coolant reservoir in the direction of arrow A in  FIG. 2 . 
     Another distinguishing feature of the device of the invention is that the portion of the coolant supply tube  32 , which in conventional coolant reservoirs is inserted into the reservoir via seals through the reservoir filler cap or through the upper part of the reservoir wall, a nipple portion  34  of the coolant supply tube for connection to the hose from the radiator (not shown), and a drain pipe  36  ( FIG. 2 ) extended from the bottom of the reservoir  24 , are molded integrally, e.g., as a single piece with the reservoir body  38 . All three tubular portions are arranged coaxially and formed in the inner corner part of the coolant reservoir  24  (see  FIG. 4 , which is a sectional view along the line IV—IV of  FIG. 2  through a part of the reservoir  24 . This drawing illustrates the position of the coolant supply tube  32  in the reservoir body  38 . The tubular portions  34 ,  32 ,  36  are formed on the side of the reservoir  24  opposite to the aforementioned open side  30  of the molded reservoir. 
     The front surface of the transparent or semitransparent coolant reservoir  24  has indication marks FULL and LOW ( FIG. 1 ), which correspond to the maximal and minimal allowable levels of the coolant in the entire system. The level of the coolant is seen through the wall of the reservoir due to its transparency or semi-transparency. 
     The coolant supply tube portion  32 , which is located inside the reservoir  24 , extends downward below the lower allowable level indication mark LOW ( FIG. 1 ) and close to the reservoir bottom  40  ( FIG. 2 ). 
     In its upper part, the reservoir  24  is also provided with a reservoir filler cap  42  ( FIG. 2 ). The overflow tube  44  of the reservoir  24  that extends outward from the reservoir  24  can be molded integrally with the neck portion  46  of the reservoir  24 . A coolant reservoir cap  42  closes the opening of the neck portion by being snugly fit and snapped on the neck portion. In order to prevent the loss of the cap  42 , it can be connected to the reservoir body  38  by a flexible cord  48 . 
     Thus, it has been shown that the invention provides a fan shroud made integrally with a coolant reservoir, which is simple in construction, inexpensive to manufacture, excludes a need for using fasteners, simplifies manufacturing and assembling procedures, reduces the number of parts required for the cooling system of the motor engine, reduces the number of manufacturing and assembling steps, and improves conditions for observation of the coolant level in the coolant reservoir. 
     Although the invention has been shown and described with reference to specific embodiments, it is understood that these embodiments should not be construed as limiting the areas of application of the invention and that any changes and modifications are possible, provided these changes and modifications do not depart from the scope of the attached patent claims. For examples, the reservoir may be located on the left side of the shroud as compared to the position thereof in  FIG. 1 . The reservoir may have the shape slightly different from the one shown in the drawings, it can be made from transparent or semitransparent plastics different from those mentioned in the specification. It can be attached to the shroud by adhesive instead of thermal welding. The shroud itself may have different shapes determined by specific model of a vehicle for which the shroud is designed.