Abstract:
A cooling unit includes a radiator and an axial flow blower that draws air through the radiator along a longitudinal axis and a cross-flow fan that draws air along a lateral axis. The cross-flow fan forces air through the radiator along the longitudinal axis. The axial flow fan draws air through the radiator long the longitudinal axis. A moveable baffle is operable to selectively block air flow from the cross-flow fan.

Description:
FIELD OF THE INVENTION 
     The present invention relates to engine cooling and more particularly to an improved cooling unit for an engine. 
     BACKGROUND OF THE INVENTION 
     Vehicular engines, whether internal combustion or fuel cell based, generate heat during the energy conversion process, which heats up the components of the engine. In some instances, this heat can damage or significantly wear the engine components. A cooling circuit is provided to avoid excessive heating of the engine components. 
     The cooling circuit circulates a flow of cooling fluid through the engine and a radiator. The cooling fluid is in heat exchange relationship with the components of the engine. Heat is transferred from the engine to the cooling fluid. The cooling fluid flows from the engine and through a radiator. The radiator acts as a heat exchanger enabling heat transfer from the cooling fluid to atmosphere. In this manner, the cooling fluid is continuously warmed by the engine and cooled by the radiator to reduce engine temperature. 
     Air flow through the radiator draws heat from the atmosphere immediately surrounding the radiator. This air flow is necessary to enable the radiator to sufficiently transfer heat from the cooling fluid. During periods of vehicle movement, natural air flow is induced. That is to say, as the vehicle moves forward, air naturally flows through the vehicle. This natural air flow increases or decreases corresponding to vehicle speed. At higher speeds, the natural air flow draws sufficient heat from the radiator. However, during periods of rest or driving at lower speeds there is insufficient natural air flow through the radiator. 
     Traditional vehicle cooling units include either an axial blower positioned in front of the radiator, an axial blower positioned behind the radiator or both. The axial blower positioned in front of the radiator is operable to blow air through the radiator. The axial blower positioned behind the radiator is operable to draw air through the radiator. During periods when the natural air flow is too light to sufficiently draw heat from the radiator, the axial blower or blowers are activated to induce air flow through the radiator. 
     Such traditional systems retain specific disadvantages. In the case of a single axial blower positioned behind the radiator, the air flow induced by the single blower may be insufficient. In the case of an axial blower positioned in front of the radiator, the axial blower itself may block significant amount of natural air flow induced by vehicle motion. As a result, the axial blower(s) are frequently switched on to compensate for the lack of natural air flow through the radiator. The frequent operation of the axial blower(s) is inefficient and increases wear of the axial blower(s). 
     SUMMARY OF THE INVENTION 
     The present invention provides a cooling unit including a radiator. The cooling unit further includes a blower that draws air through the radiator along a longitudinal axis and a cross-flow fan that draws air along a lateral axis. The cross-flow fan forces air through the radiator along the longitudinal axis. 
     In one feature, the cross-flow fan includes a flap that is movable between an open position to enable air flow from the cross-flow fan and a closed position to block air flow from the cross-flow fan. A biasing member biases the flap in the open position. Further, when the flap is in the closed position the cross-flow fan stops operating. 
     In another feature, when in the open position the flap partially blocks natural air flow into the radiator. 
     In yet another feature, an intake extends along the lateral axis and functions to draw air through the cross-flow fan. 
     In still another feature, air forced through the radiator and air drawn through the radiator along the longitudinal axis cools a fluid flowing through the radiator. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is a functional block diagram of a vehicle having a cooling unit including a cross-flow fan; and 
     FIG. 2 is a side view of the functional block diagram of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     Referring now to FIGS. 1 and 2, a vehicle  10  is shown including a cooling unit  12  and an engine  14 . As used herein engine  14  used in a broad sense to include any energy conversion device including an internal combustion engine, a fuel cell engine or other types of energy conversion devices capable of powering a vehicle. A cooling fluid (not shown) circulates between the engine  14  and the cooling unit  12 . The cooling fluid flows into the engine  14  through a conduit  16  and is in heat exchange relationship with components of the engine  14 . Heat transfer occurs from the engine  14  to the cooling fluid, thereby heating the cooling fluid and cooling the engine  14 . The heated cooling fluid flows through a conduit  18  from the engine  14  to the cooling unit  12 . Traditionally, a pump (not shown) is provided and is driven by the engine  14  to induce circulation of the cooling fluid between the engine  14  and the cooling unit  12 . In addition, a thermostatic value (not shown) may be utilized to selection control flow of the cooling fluid. 
     The vehicle  10  also includes a front fascia  20  and wheel wells  22  disposed on either side. The wheel wells  22  house wheels (not shown) that are driven by the engine  14  in the case of a front wheel drive FWD vehicle. The front fascia  20  includes a plurality of vents  24  formed therethrough. The fascia  20  protects the engine  14  and cooling unit  12  while enabling air flow through the vents  24 . Forward driving motion of the vehicle  10  induces air flow indicated by the arrows labeled A through the vents  24  and into the cooling unit  12 . This natural air flow cools the cooling fluid flowing through the cooling unit  12  so that it may circulate back to the engine  14  to further cool the engine  14 . 
     According to the present invention, the cooling unit  12  includes a radiator  26 , a cross-flow fan  28  and an axial blower  30 . The radiator  26  is in fluid communication with the engine  14  through the conduits  16 , 18 . The radiator  26  is a heat exchanger that cools the cooling fluid circulated therethrough. The cooling fluid re-circulates back to the engine  14  to further cool the engine  14 . The radiator  26  is a conventional lined tube heat exchanger that includes air flow passages (not shown) and fins (not shown) through which air flows in tubes which carries the cooling fluid. Heat radiates from the radiator  26  to cool the cooling fluid circulating therein. The radiated heat is drawn away from the radiator  26  by the air flow. 
     Occasionally, there is insufficient air flow through the radiator  26  to achieve the desired heat transfer. In such cases, the cooling fluid is not cooled to a desired temperature. A temperature sensor  40  monitors the temperature of the cooling fluid. The temperature sensor  40  generates a temperature signal that is sent to a controller  42 . If the cooling fluid temperature rises above a predetermined threshold, the controller  42  switches on the cross-flow fan  28  and axial blower  30  to induce supplemental air flow through the radiator  26 . Otherwise, the controller switches off the cross-flow fan  28  and axial blower  30 . 
     The axial blower  30  is located between the radiator  26  and the engine  14 . The axial blower  30  includes a conventional fan used in automotive applications that rotates to induce air flow. As the fan rotates air is drawn along a longitudinal axis A. The air is drawn through the radiator  26  and the axial blower  30  and flows toward the engine  14 . In this way, the axial blower  30  induces air flow through the radiator  26  to draw heat from the radiator  26 . In addition, the axial blower  30  will direct air over and around the engine  14  to effect cooling though connection. 
     The cross-flow fan  28  is disposed behind the fascia  20  and positioned so as not to obstruct natural air flow through the vents  24 . Thus, during vehicle driving natural air flow flows through to the radiator  26  unobstructed. The cross-flow fan  28  includes a housing, a centrifuged fan  32 , located within a fan housing  33  having an outlet  34 . The fan rotates to draw air into the cross-flow fan  28  along a lateral axis Y through a vent  38  or plurality of vents  38  located laterally against the radiator  26 . The vents  38  enable air to be drawn into the cross-flow fan  28  from the sides of the vehicle  10 . The vents  38  can open to atmosphere through the sides of the vehicle  10  or the wheel wells  22 . The fan pushes the air through the outlet  34  blowing the air towards the front face of the radiator  26 . In this way, the cross-flow fan  28  induces air flow through the radiator  26  to draw heat from the radiator  26 . 
     A flap or moveable baffle  36  is secured to the fan housing by hinge  44  and is pivotable between an open position and a closed position (shown in phantom). In addition, a switch  46  may be employed with the moveable baffle to ? the cross-flow fan  32  when the movable baffle  36  is in the closed position. In the open position, the flap  36  partially obstructs natural air flow through the vents  24  and enables air flow through the outlet  34 . In the closed position, the flap  30  obstructs air flow through the outlet  34  and enables full natural air flow through the vents  24 . 
     Preferably, movement of the flap  36  between the open and closed positions is based on the natural air flow through the vents  24 . More specifically, as the vehicle  10  increases speed the natural air flow through the vents correspondingly increases. The increased natural air flow urges the flap  36  toward the closed position against the biasing force of the biasing mechanism  44 . Thus, natural air flows unobstructed through the radiator  26 . Although the outlet  34  of the cross-flow fan  28  is blocked, supplemental air flow is not needed with the increased natural air flow. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.