Abstract:
A structure for cooling one or more units built in a hybrid vehicle, where the structure is simple and can be inexpensively realized, and has a high cooling efficiency. The hybrid vehicle has an internal combustion engine and high-voltage units which include a motor which assists driving power of the engine and also functions as a power generator, a high-voltage storage battery for storing generated power, and a high-voltage controller provided between the motor and the storage battery. At least one of the high-voltage units is provided in an air intake passage for the engine, through which an air passes while cooling said at least one of the high-voltage units.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a structure for cooling high-voltage units built in a hybrid vehicle, such as a high-voltage battery, a high-voltage controller, a motor, and the like.  
           [0003]    2. Description of the Related Art  
           [0004]    Japanese Unexamined Patent Application, First Publication No. 2002-4860 discloses a structure for cooling units built in a hybrid vehicle, in which water jackets are attached to each high-voltage unit, such as an electric motor, an inverter, and the like, and the cooling operation is performed by using both the internal combustion engine and the cooling water. This cooling system has a radiator and a radiator fan which are dedicatedly provided for the high-voltage units and thus are independent of the internal combustion engine, and the system also has a dedicated electric pump and a dedicated throttle valve for controlling temperature, thereby controlling the temperature of the cooling water, which is suitable for the high-voltage units.  
           [0005]    However, in the above conventional structure for cooling the units built in the hybrid vehicle, a cooling system independent of the internal combustion engine is necessary, so that the piping arrangement and the control are complicated. In addition, the dedicated water jacket, electric pump, radiator fan, and the like are necessary for each high-voltage unit, thereby increasing the weight of the vehicle.  
           [0006]    Additionally, the control temperatures for the high-voltage units are generally lower than the control temperature for the internal combustion engine. Here, the control temperature is an optimal temperature which is determined for each unit or device and is maintained by control. Therefore, it is necessary to cool the cooling water to have a temperature suitable for the high-voltage units, and thus the operation of this cooling system is inefficient.  
         SUMMARY OF THE INVENTION  
         [0007]    In consideration of the above circumstances, an object of the present invention is to provide a structure for cooling one or more units built in a hybrid vehicle, where the structure is simple and can be inexpensively realized, and has a high cooling efficiency.  
           [0008]    Therefore, the present invention provides a structure for cooling high-voltage units built in a hybrid vehicle, wherein:  
           [0009]    the hybrid vehicle comprises an internal combustion engine (e.g., an engine  4  in an embodiment explained below) and high-voltage units which include a motor (e.g., a motor  8  in the embodiment explained below) which assists driving power of the engine and also functions as a power generator, a high-voltage storage battery (e.g., a storage battery  9  in the embodiment explained below) for storing generated power, and a high-voltage controller (e.g., a high-voltage controller  11  in the embodiment explained below) provided between the motor and the storage battery; and  
           [0010]    at least one of the high-voltage units is provided in an air intake passage (e.g., an air intake passage  6  in the embodiment explained below) for the engine, through which an air passes while cooling said at least one of the high-voltage units.  
           [0011]    According to the above structure, the intake air for the engine can be used as the cooling air for cooling the motor, the storage battery, and the high-voltage controller which are arranged in the air intake passage. Each high-voltage unit is provided in the air intake passage of the engine compartment; thus, the space necessary for arranging the units can be saved. Therefore, the structure can be efficiently built into a hybrid vehicle.  
           [0012]    Preferably, at least two of the high-voltage units are arranged in the air intake passage, which starts from an air intake inlet (e.g., an air intake inlet  16  in the embodiment explained below) and reaches the engine, in order of a control temperature from the lowest to the highest, where the control temperature is an optimal temperature determined for each unit, which is maintained by control.  
           [0013]    In this case, as a typical example, the storage battery, the high-voltage controller, and the motor are arranged in this order in the air intake passage which starts from the air intake inlet and reaches the engine.  
           [0014]    Accordingly, the high-voltage units can be arranged from the upstream side of the air intake passage, in order of the control temperature from the lowest to the highest; therefore, each unit can be efficiently cooled by the air which is drawn from the air intake inlet and which passes through the air intake passage.  
           [0015]    The high-voltage controller may include at least one of an inverter, a DC-DC converter, and an electronic control unit for the motor.  
           [0016]    As a preferable example:  
           [0017]    an air cleaner unit for cleaning the air is provided in the air intake passage; and  
           [0018]    a case of the air cleaner unit has an opening to which the high-voltage controller is attached in a sealed state so as to close the opening.  
           [0019]    In this case, the air cleaner unit may have cooling fins for assisting the flow of the air, which protrude towards an inner space of the air cleaner unit.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a plan view showing the general structure of the engine compartment of a hybrid vehicle in an embodiment according to the present invention.  
         [0021]    [0021]FIG. 2 is a plan view for showing and explaining the cooling structure in the embodiment.  
         [0022]    [0022]FIG. 3 is a sectional view in a horizontal direction of the air cleaner case in the embodiment.  
         [0023]    [0023]FIG. 4 is a side view which is viewed along the direction indicated by arrow A in FIG. 3.  
         [0024]    [0024]FIG. 5 is a sectional view in a horizontal direction of the motor in the embodiment.  
         [0025]    [0025]FIG. 6 is a sectional view taken along line B-B in FIG. 5.  
         [0026]    [0026]FIG. 7 is a sectional view taken along line C-C in FIG. 5. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    Hereinafter, an embodiment according to the present invention will be explained with reference to the drawings.  
         [0028]    [0028]FIG. 1 is a diagram showing the general structure of the engine compartment  1  of a hybrid vehicle in the present embodiment. In this hybrid vehicle, the current of the storage battery  9  as a DC (direct current) power supply is converted from DC to AC (alternating current) by using an inverter provided in the high-voltage control unit  11 , and the converted current is supplied to the motor  8 . This motor  8  is used as a generator, and a portion of the power output from the engine or the kinetic energy of the vehicle is regenerated. The voltage of the regenerated power is boosted using a DC-DC converter in the high-voltage control unit  11  and is then stored in the storage battery  9  via the inverter.  
         [0029]    In the front portion of the engine compartment  1 , a radiator  2  for the engine is provided at the left side, and a condenser  3  for the air-conditioner is provided at the relatively right side. The arrow “Fr” in FIG. 1 (also in FIGS. 2, 3, and  5  which will be explained below) indicates the front side of the vehicle.  
         [0030]    The engine  4  is provided behind the radiator  2 , and an air intake passage  6  is provided, which is arranged from behind the throttle body  5  of the engine  4 , in the counterclockwise direction in the engine compartment  1 .  
         [0031]    In the air intake passage  6 , the motor  8  is positioned at the downstream side (with respect to the air flow) of the air cleaner case  7 , and the storage battery  9  is positioned at the upstream side of the air cleaner case  7 . In addition, the high-voltage controller  11  is positioned in the air cleaner case  7  (the detailed structure will be explained below) and at the upstream side of the air cleaner element  10 . Therefore, in the air intake passage  6  of the engine  4 , the storage battery  9 , the high-voltage controller  11 , and the motor  8  are arranged in turn from the upstream side.  
         [0032]    The engine  4  is laid on its side, and the motor  8  is arranged behind the engine  4  in parallel to the engine  4 . The drive shaft  12  of the motor  8  and the crank shaft  13  of the engine  4  are coupled via the belt  14 . Therefore, when the electrical power is supplied to the motor  8 , the driving power of the engine  4  is assisted via the belt  14 . In addition, when the vehicle is decelerated, kinetic energy is supplied from the crank shaft  13  of the engine  4  via the belt  14  to the motor  8 , and a portion of the supplied kinetic energy is regenerated as electrical power. Here, this motor  8  also functions as a starter of the engine  4 .  
         [0033]    The air cleaner case  7  is provided at the right side of the motor  8 , and the air intake duct  15  is provided at the front right side of the air cleaner case  7 . The storage battery  9  is positioned in the air intake duct  15 .  
         [0034]    The air intake inlet  16  of the air intake duct  15  is provided at the right side and the frontmost portion of the engine compartment  1 , so as not to receive the exhaust air from the radiator  2  and the condenser  3 . The air intake inlet  16  is open towards the front side.  
         [0035]    Below, with reference to FIGS.  2  to  7 , the concrete structure of the cooling system according to the present embodiment will be explained.  
         [0036]    As shown in FIG. 2, the motor  8  has a substantially cylindrical shape, where the drive shaft  12  is provided in the axial direction of the cylindrical shape. The motor  8  has a housing  17  and a diffuser  18  which is attached to the right-side end of the housing  17  and which extends in the direction of the drive shaft  12 .  
         [0037]    At the head of the diffuser  18  in the direction of the drive shaft  12 , an air-take inport  19  is provided, and an air intake outport  20  is provided at the left-side end of the housing  17  and in the side wall which faces the engine  4 .  
         [0038]    In the air cleaner case  7 , the cover  22  is attached to the front portion of the case main body  21 , thereby forming a closed space having a substantially box shape. The air cleaner element  10  is provided in the air cleaner case  7  and between the case main body  21  and the cover  22 .  
         [0039]    An air intake inport  23  is attached to the right side wall of the case main body  21 , and an air intake outport  24  is attached to the left side wall of the cover  22 .  
         [0040]    The air intake inlet  16 , which is open towards the front side (in FIG. 2, towards the right side for convenience of illustration), is formed in the air intake duct  15 , and an air intake outport  25  is formed at the side opposite to the side where the air intake inlet  16  is provided.  
         [0041]    The outport  25  of the air intake duct  15  and the inport  23  of the air cleaner case  7  are coupled with each other via a pipe  26 , the outport  24  of the air cleaner case  7  and the inport  19  of the motor  8  are coupled with each other via a pipe  27 , and the outport  20  of the motor  8  and the throttle body  5  of the engine  4  are coupled with each other via a pipe  28 , so that the air intake passage  6  is continuously formed from the air intake inlet  16  to the throttle body  5 .  
         [0042]    As shown in FIGS. 3 and 4, in the air cleaner case  7 , the cover  22  is attached to the case main body  21  by using clips  29 , and the dry air cleaner element  10  is fastened between the case main body  21  and the cover  22 .  
         [0043]    The rear wall portion  30  of the case main body  21  is open in this embodiment, and the high-voltage controller  11  is attached so as to close the rear wall portion  30 . That is, the high-voltage controller  11  functions as a part of the case main body  21 .  
         [0044]    The high-voltage controller  11  includes an inverter, a DC-DC converter, a motor ECU (electronic control unit), and the like, and has a thin shape so as not to increase the size of the air cleaner case  7 . Here, the motor ECU controls the amounts of power assistance, regeneration, and the like of the motor, via the inverter.  
         [0045]    The high-voltage controller  11  has a plurality of cooling fins  31  which protrude towards the inner space of the air cleaner case  7 . This high-voltage controller  11  is inclined with respect to the air-drawing direction of the inport  23  of the air cleaner case  7 , so that the high-voltage controller  11  can more easily receive the air.  
         [0046]    The cooling fins  31  is arranged from the right side wall  32  to the left side wall  33  of the case main body  21  and is arranged substantially parallel to the air-drawing direction of the inport  23  (see FIG. 4).  
         [0047]    In FIG. 3, the inport  23  is arranged in a manner such that an end of the opening  34  of the inport  23  contacts the rear edge  35  of the right side wall  32 , that is, contacts the high-voltage controller  11 . In addition, the cooling fins  31  of the high-voltage controller  11  protrude in a manner such that the protruding fins secure a height (measured from the end which contacts the rear edge  35 ) up to the other end of the opening  34 .  
         [0048]    As shown in FIG. 5, the housing  17  forms the outer shape of the motor  8 , where the motor  8  may be a three-phase motor. That is, the housing  17  is a constituent of the motor  8  and forms a closed space inside the housing.  
         [0049]    The rotor  36  and the stator  37  are provided in a center portion in the right-left direction of the housing  17 . The drive shaft  12  is coupled with the rotor  36  and is rotatably supported by the housing  17 . The three-phase wound stator  37  is fixedly supported by the housing  17 .  
         [0050]    As shown in FIG. 6, a plurality of air-drawing portions  38  are provided in the rotor  36 , which are arranged parallel to the drive shaft  12 , so that the air drawn into the housing  17  can pass through the air-drawing portions  38 . In addition, the gap  40  between the magnets  39  connected to the rotor  36  and the stator  37  also functions as an air passage.  
         [0051]    As shown in FIG. 5, in the right side wall  41  of the housing  17 , a plurality of air holes  42  are provided, and the diffuser  18  is connected to the right side wall  41  in a sealed state so that no gap is present between the wall and the diffuser. Accordingly, the air, which is drawn into the housing  17  via the diffuser  18 , passes through the air-drawing portions  38  and the gap  40  and is then transferred to the outport  20 .  
         [0052]    At the left side of the housing  17 , a pulley  43  is provided, which is coupled with the drive shaft  12 , and at the left side of the engine  4 , a pulley  44  is provided, which is coupled with the crank shaft  13  (see FIG. 2). In addition, the belt  14  is provided around the pulleys  43  and  44  so as to couple the engine  4  and the motor  8  with each other.  
         [0053]    At the right-side end of the housing  17 , a fan  45  coupled with the drive shaft  12  is provided. This fan  45  is operated together with the drive shaft  12  of the motor  8 , thereby promoting the air intake operation. The fan  45  also functions as a supercharger for forcing the air into the outport  20  which is provided at the left-side end of the housing  17  (see FIG. 7).  
         [0054]    As shown in FIG. 2, the air intake duct  15  has a container  47  which has an opening  46 . This container  47  is an expanded portion in the air intake duct  15 , and the storage battery  9  is provided in this expanded portion.  
         [0055]    The portion (or gap) between the storage battery  9  and the opening  46  is sealed, so that the air drawn from the air intake inlet  16  passes through a gap between the air intake duct  15  and the storage battery  9  and is then drawn into the air cleaner case  7 .  
         [0056]    The operation of the present embodiment will be explained below.  
         [0057]    When the engine  4  is started, the air is drawn from the air intake inlet  16  into the air intake duct  16 , as indicated by chain arrows (drawn with two-dot chain lines) in FIG. 1. In this process, the drive shaft  12  of the motor  8  rotates via the belt  14 , and accordingly, the fan  45  is operated, so that the inside of the air intake passage  6  has a negative pressure and the air intake operation is progressed.  
         [0058]    The storage battery  9  in the air intake duct  15  is cooled by the air drawn from the air intake inlet  16 . Here, the air intake inlet  16  is positioned at the frontmost portion of the vehicle body and thus does not receive the exhaust air from the radiator  2  and the condenser  3  and the heat of the engine  4  and the like, so that it is possible to maintain the temperature of the air drawn from the air intake inlet  16  at a suitable low level.  
         [0059]    The air which has cooled the storage battery  9  is discharged from the outport  25  and is supplied to the air cleaner case  7  via the pipe  26 . The high-voltage controller  11  is cooled by the air drawn into the air cleaner case  7  from the inport  23 . Here, the control temperature for the storage battery  9  is lower than the control temperature for the high-voltage controller  11 ; thus, the high-voltage controller  11  can be cooled by the air which has been subjected to the heat exchange with the storage battery  9 .  
         [0060]    The high-voltage controller  11  is inclined with respect to the air-drawing direction of the inport  23 ; thus, the high-voltage controller  11  can easily receive the air. In addition, the cooling fins  31  are arranged in substantially parallel to the air-drawing direction of the inport  23 ; thus, the air easily flows along the cooling fins  31 . Therefore, the high-voltage controller  11  can be efficiently cooled by the air drawn from the inport  23 .  
         [0061]    Additionally, the high-voltage controller  11  is provided at the upstream side of the air cleaner case  7 , and the cooling fins  31  are provided so as to cover the height from one end to the other end of the opening  34  of the inport  23  (refer to FIG. 3). Therefore, the cooling fins  31  themselves function as a simplified filter. Therefore, it is possible to prevent dust of relatively large particle size from entering the air cleaner case  7  and to reduce dirt on the air cleaner element  10 .  
         [0062]    The air, which has cooled the high-voltage controller  11 , passes through the air cleaner element  10  and is discharged from the outport  24 . This discharged air is supplied to the motor  8  via the pipe  27 . The air drawn from the inport  19  of the diffuser  18  into the housing  17  passes in the direction along the drive shaft  12 , thereby cooling the motor  8 . Here, the control temperature for the high-voltage controller  11  is lower than that of the motor  8 ; thus, the air, which has been subjected to the heat exchange with the high-voltage controller  11 , can cool the motor  8 .  
         [0063]    Here, the motor  8  is provided at the downstream side of the air cleaner element  10 ; thus, it is possible to prevent foreign objects from entering the housing  17  together with the air.  
         [0064]    The air which has cooled the motor  8  passes through the fan  45  and is discharged from the outport  20 . This overpressurized air is supplied to the throttle body  5  via the pipe  28 .  
         [0065]    According to the above-explained embodiment, the high-voltage units such the storage battery  9 , the high-voltage controller  11 , and the motor  8  can be cooled without providing a dedicated cooling system. Therefore, the cooling structure, which is light and inexpensive, can be realized using a small number of parts.  
         [0066]    In addition, each high-voltage unit is positioned in the air intake passage  6 ; thus, the space necessary for arranging the units can be saved, and it is unnecessary to ensure a space for arranging the units in an interior of the vehicle or the like. Therefore, the space in the interior of the vehicle can be effectively used.  
         [0067]    In the above embodiment, the high-voltage units are arranged from the upstream side in order of the control temperature from the lowest to the highest. Therefore, each unit can be efficiently cooled by the same air.  
         [0068]    In addition, the operation of the fan  45  can progress the air intake operation and thus improve the efficiency of cooling the storage battery  9 , the high-voltage controller  11 , and the motor  8  in the air intake passage  6 , This fan  45  also functions as a supercharger; thus, the performance of the engine can be improved.  
         [0069]    Also in the above embodiment, the high-voltage controller  11  is attached so as to form a part of the air cleaner case  7 ; thus, the rigidity of the faces of the air cleaner case  7  can be improved and sounds (or noises) generated during the air intake operation can be reduced. In addition, the cooling fins  31  are provided towards the inner space of the air cleaner case  7 ; thus, the space in the air cleaner case  7  can be effectively used.  
         [0070]    The present invention is not limited to the above-explained embodiment, and modifications are possible within the scope and spirit of the present invention.  
         [0071]    For example, if all of the storage battery  9 , the high-voltage controller  11 , and the motor  8  cannot be arranged in the air intake passage  6 , at least one of these units may be provided in the air intake passage  6 . In addition, the motor  8  is cooled in the housing  17  in the above embodiment; however, the motor  8  (which has the housing  17 ) may be contained in the air intake passage  6  and the motor  8  may be cooled from the outside of the housing  17 .  
         [0072]    In another variation, a clutch may be provided in the transmission system for the motor  8  and the engine  4 , so that the power transmission between the drive shaft  12  of the motor  8  and the crank shaft  13  of the engine  4  can be connected and disconnected.  
         [0073]    In another variation, the motor  8  and the engine  4  may be coupled using a combination of a chain and a sprocket instead of the combination of the pulleys  43  and  44  and the belt  14 .