Abstract:
An air conditioning device for a vehicle, provided with: an air blower unit having a first introduction path and a second introduction path through which inside air or outside air is sucked into an upper fan and a lower fan by switching between switching doors; and an air conditioning unit for discharging air into the vehicle interior. The air conditioning device for a vehicle is characterized in that the first introduction path is an introduction path into which only the outside air is introduced when the inside air and the outside air are sucked separately and in that an outside air amount adjustment mechanism for limiting the amount of delivery of the outside air according to the speed of the vehicle is provided in the first introduction path or at a position downstream thereof to reduce the generation of wind noise at a defroster opening or a face opening.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a vehicular air-conditioning system which is designed to suppress the occurrence of a whistling sound due to slight door opening and to prevent detraction of comfort in air blown in a passenger compartment due to an increase in the flow rate of air due to the ram pressure (pressure of air due to movement of vehicle). 
       BACKGROUND ART 
       [0002]    At the time of the FOOT (foot) mode which blows air-conditioned air toward the feet of the driver and passengers, sometimes an extremely large amount of air-conditioned air is distributed through the FOOT vents and a slight flow rate of air is blown through the DEF (defroster) vents to the vehicle windshield side to defog the vehicle windshield. In such a FOOT mode, sometimes the vent mode door is operated to a slightly open position. In this case, the flow of air is rapidly throttled by the slight clearances of the DEF vents and FACE vents and air is ejected through the slight clearances at a fast speed, so there is the problem of a whistling sound being caused. 
         [0003]    To deal with this problem, there is known PLT 1 which is aimed at suppressing the occurrence of problems due to the slightly open position of a vent mode door.  FIG. 1A  is a schematic cross-sectional view of an air-conditioning unit of PLT 1, while  FIG. 1B  shows the ratio of flow rates of air and door patterns of different modes in PLT 1. Below, the vehicular air-conditioning system of PLT 1 will be simply explained. 
         [0004]    The vehicular air-conditioning system of PLT 1 is divided into two parts: an air-conditioning unit  10  and a blower unit  9  which blows air to this air-conditioning unit  10 . The blower unit  9  is arranged inside the instrument panel at the front of the passenger compartment while offset from the center part to the front passenger seat side. As opposed to this, the air-conditioning unit  10  is arranged inside the instrument panel at the front of the passenger compartment at the substantially center part in the left-right (width) direction of the vehicle. The air-conditioning unit  10  has a plastic air-conditioning case  11  in which is formed an air passage through which air is blown toward the inside of the passenger compartment. Inside this air-conditioning case  11 , an evaporator  12  which forms the cooling-use heat exchanger and a heater core  13  which forms the heating-use heat exchanger are installed. At a portion inside the air-conditioning case  11  at the front-most side of the vehicle, an air inlet space  14  is formed. Into this air inlet space  14 , air blown from a centrifugal type blower of the blower unit  9  flows. 
         [0005]    Inside of the air-conditioning case  11 , the evaporator  12  is arranged at the portion right after the air inlet space  14 . This evaporator  12 , as is well known, absorbs the latent heat of evaporation of a low pressure refrigerant of a refrigeration cycle from the blown air to cool the blown air. Further, at the downstream side of the flow of air of the evaporator  12  (vehicle rear side), the heater core  13  is arranged a predetermined distance from the evaporator  12 . The heater core  13  reheats the cold air which passes through the evaporator  12 . At the inside, high temperature water (engine cooling water) flows from the vehicle engine. This warm water is used as a heat source to heat the air. 
         [0006]    The air passage of the air which passes through the upstream side of the flow of air of the heater core  13  is partitioned by a first upstream side partition member  15  inside the air-conditioning case  11  to an upstream side first upstream side passage  16  and a downstream side second upstream side passage  17 . This first upstream side partition member  15  is formed so as to extend from an air outlet side of the evaporator  12  to an air inlet side of the heater core  13  and is formed to extend across the entire length in the left-right direction of the vehicle in the space inside the air-conditioning case  11 . In the air passage of the air-conditioning case  11 , at the upper portion and lower portion of the heater core  13 , a first bypass passage  18  and a second bypass passage  19  which bypass the heater core  13  and through which air (cold air) flows are formed. The second upstream side passage  17  at the upstream side of the heater core  13  is formed so that the passage cross-sectional area becomes larger than the passage cross-sectional area of the first upstream side passage  16  (for example, a 1:9 ratio). 
         [0007]    Between the evaporator  12  and the heater core  13 , a first air mix door  20  and a second air mix door  21  are arranged. The air mix doors  20  and  21  are configured by flat-plate shaped sliding doors. The air mix doors  20  and  21  are moved in a direction intersecting the flow of air of the air passage by drive gears  20   a  and  21   a  so as to open and close the air passage. The first air mix door  20  and the second air mix door  21  form temperature adjusting means for adjusting the temperature of the air blown to the windshield inside the passenger compartment and the passenger side inside the passenger compartment by adjustment of the ratio of flow rates of air. 
         [0008]    At the downstream side of the flow of air of the heater core  13  (vehicle rear side), a first downstream side partition member  22  which extends upward from a position on a line extending from the first upstream side partition member  15  to the vehicle rear is provided. Furthermore, from the end of the first downstream side partition member  22 , a first switching door  23  is provided so as to extend to the top wall surface of the air-conditioning case  11  between the defroster vents  26  and face vents  28 . The first switching door  23  is arranged to be able to rotate about a rotary shaft  23   a.  Due to this first downstream side partition member  22  and first switching door  23 , a first downstream side passage  24  which guides air to the defroster vents  26  and a second downstream side passage  25  which guides air to the face vents  28  and foot vents  30  are formed. The defroster vents  26 , face vents  28 , and foot vents  30  are respectively opened and closed by a plate-shaped defroster door  27 , face door  29 , and foot door  31  which can rotate about rotary shafts  27   a,    29   a,  and  31   a.    
         [0009]    If the first switching door  23  is operated to the one-dot chain position of  FIG. 1 , the first switching door  23  closes the connection of the first downstream side passage  24  and the second downstream side passage  25  (this being referred to as the “partitioned position”). As opposed to this, if the first switching door  23  is operated to the solid line position of  FIG. 1 , the first downstream side passage  24  and the second downstream side passage  25  are communicated (this being referred to as the “communicated position”). 
         [0010]    At the time of the foot mode, the defroster vents  26  and foot vents  30  are fully opened by the respectively corresponding vent mode doors  27  and  31 . The opening degree of the defroster vents  26  is not limited to fully opened. For example, a half opened extent, not a slightly open position, is also possible. The face vents  28  are closed by the face door  29 . The first switching door  23 , as shown by the one-dot chain line of  FIG. 1 , is operated to the “partitioned position” which partitions the passage to the first downstream side passage  24  and the second downstream side passage  25  at the downstream side of the heater core  13 . Due to the first upstream side partition member  15 , the passage cross-sectional area of the second upstream side passage  17  is formed larger than the passage cross-sectional area of the first upstream side passage  16 , so the air which passes through the evaporator  12  mainly flows to the second upstream side passage  17  and a slight flow rate of air flows to the first upstream side passage  16 . 
         [0011]    In the foot/defroster mode, in the same way as the foot mode, the defroster vents  26  and foot vents  30  are fully opened by the corresponding vent mode doors  27  and  31 , while the face vents  28  are closed by the face door  29 . The first switching door  23 , as shown by the solid line position of  FIG. 1 , is operated to the “communicated position” which communicates the first downstream side passage  24  and the second downstream side passage  25  at the downstream side of the heater core. Due to this, compared with the foot mode, it is possible to increase the flow rate of the air which passes through the defroster vents  26 . 
         [0012]    In this way, in the art of PLT 1, in the foot mode, even if not setting the defroster door  27  at the slightly open position, it is possible to blow mainly air from the foot vents  30  and make the flow rate of air which flows into the defroster vents  26  a slight flow rate. For this reason, it is possible to make the flow ratio of air which is blown out from the defroster vents  26  and foot vents  30  a suitable ratio and possible to suppress problems such as the abnormal sound which occurs due to the slightly open position of the defroster door  27   
         [0013]    In the art of this PLT 1, as explained above, it is possible to suppress the occurrence of a whistling sound due to the slight door opening. However, the switching door is set to a state where it is fastened at the partitioned position or the communicated position, so when the vehicle is moving at a high speed in the outside air mode, the ram pressure applied to the front surface of the vehicle (pressure generated by being pushed in from the outside when moving) causes the rise in pressure at the scroll casing outlet of the blower to end up increasing. For this reason, due to the increase in the flow rate of air flowing into the passenger compartment and the air-conditioned air in the passenger compartment ending up being changed and due to the feeling on the part of the driver and passengers of the speed of the flow ending up becoming greater than targeted, there is the problem that comfort is not obtained. Further, since the ratio of top and bottom flow rates of air is fixed, to comply with specific vehicle specifications, it is necessary to completely change the top and bottom partitioned position and the layout accompanying the same. The problem of the greater cost and work also arises. 
       CITATIONS LIST 
     Patent Literature 
       [0014]    PLT 1: Japanese Unexamined Patent Publication No. 2009-113538A 
         [0015]    PLT 2: Japanese Patent Unexamined Publication No. 2000-016050A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0016]    The present invention, in consideration of the above problems, provides a vehicular air-conditioning system which is designed to suppress the occurrence of a whistling sound due to a slight door opening and to prevent comfort being detracted from due to the increase in the air flow rate due to the ram pressure. 
       Solution to Problem 
       [0017]    To solve the above problems, the aspect of the invention of claim  1  provides a vehicular air-conditioning system which is provided with a blower unit ( 9 ) which has an upper fan ( 52 ), a lower fan ( 53 ), switching doors ( 67 ,  68 ,  69 ,  67 ′,  68 ′) for switching passages, a first introduction passage ( 71 ) which sucks inside air or outside air into the upper fan ( 52 ), a second introduction passage ( 70 ) which sucks inside air or outside air into the lower fan ( 53 ), and a first discharge passage ( 81 ) and second discharge passage ( 82 ) which discharge air blown from the upper fan ( 52 ) and the lower fan ( 53 ) in a two-layer state and an air-conditioning unit ( 10 ) which adjusts the temperature of air blown from the blower unit ( 9 ) by an evaporator ( 12 ), air mix door, and heater core ( 13 ) and blows air out from defroster vents ( 26 ), face vents ( 28 ), and foot vents ( 30 ) into the passenger compartment, wherein the first introduction passage ( 71 ) is an introduction passage in which only outside air is introduced when sucking in inside air and outside air separately, which is provided with an outside air flow adjustment mechanism which limits the amount of outside air which is blown in accordance with the vehicle speed at the first introduction passage ( 71 ) or downstream, and which suppresses the occurrence of a whistling sound of the defroster vents ( 26 ) or the face vents ( 28 ). 
         [0018]    Due to this, even if not opening the defroster door or face door slightly, the flow rate of air which flows through the top side can be adjusted, so it is possible to keep down the occurrence of a whistling sound due to slight door opening while adjusting the flow rate of air to a suitable level in response to an increase in the flow rate of air due to ram pressure at the time when the vehicle is moving at a high speed without detracting from comfort. 
         [0019]    The aspect of the invention of claim  2  provides the aspect of the invention of claim  1 , wherein the first introduction passage ( 71 ) and the second introduction passage ( 70 ) have inside air or outside air introduced by three suction modes of a two-layer inside/outside air mode which sucks in the inside air and outside air separately, an outside air mode, and an inside air mode. 
         [0020]    The aspect of the invention of claim  3  provides the aspect of the invention of claims  1  and  2 , wherein the first introduction passage ( 71 ) communicates with the defroster vents ( 26 ) and the face vents ( 28 ), and the second introduction passage ( 70 ) communicates with the foot vents ( 30 ). 
         [0021]    The aspect of the invention of claim  4  provides the aspect of the invention of any one of claims  1  to  3 , wherein the outside air flow adjustment mechanism is a throttling door ( 72 ) which is provided at the first introduction passage ( 71 ). Due to this, advantageous effects the same as the aspect of the invention of claim  1  can be obtained, the amount of work imposed on the fan can be reduced, and an energy saving effect can be obtained. 
         [0022]    The aspect of the invention of claim  5  provides the aspect of the invention of any one of claims  1  to  3 , wherein the outside air flow adjustment mechanism is an iris shutter type throttling door ( 75 ) which is provided at the first introduction passage ( 71 ). Due to this, advantageous effects the same as in the aspect of the invention of claim  4  are obtained. 
         [0023]    The aspect of the invention of claim  6  provides the aspect of the invention of any one of claims  1  to  3 , wherein the outside air flow adjustment mechanism is a throttling door ( 78 ) which is provided at a first discharge passage ( 81 ) which extends from the upper fan ( 52 ) to the evaporator ( 12 ). Due to this, advantageous effects the same as in the aspect of the invention of claim  1  are obtained. 
         [0024]    The aspect of the invention of claim  7  provides the aspect of the invention of any one of claims  1  to  3 , wherein the outside air flow adjustment mechanism is an opening/closing door ( 79 ) which is provided at an up-down passage partitioning member ( 73 ) between a first discharge passage ( 81 ) which extends from the upper fan ( 52 ) to the evaporator ( 12 ) and a second discharge passage ( 81 ) which extends from the lower fan ( 52 ) to the evaporator ( 12 ). Due to this, advantageous effects the same as in the aspect of the invention of claim  1  are obtained. 
         [0025]    The aspect of the invention of claim  8  provides the aspect of the invention of any one of claims  1  to  3 , wherein the outside air flow adjustment mechanism is a variable nose part clearance mechanism ( 83 ) which is provided at a nose part of the upper fan ( 52 ). Due to this, advantageous effects the same as in the aspect of the invention of claim  4  are obtained. 
         [0026]    Note that the reference numerals given above are illustrations showing the correspondence with specific means described in the embodiments described later. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0027]      FIG. 1(   a ) is a schematic cross-sectional view of an air-conditioning unit of PLT 1, while  FIG. 1(   b ) shows the ratios of flow rates of air flow and door patterns of different modes of PLT 1. 
           [0028]      FIG. 2  is a schematic explanatory view of an inside/outside air suction FOOT mode in an embodiment of the present invention. 
           [0029]      FIG. 3  is a schematic explanatory view of an outside air suction FOOT mode in an embodiment of the present invention. 
           [0030]      FIG. 4  is a schematic explanatory view of an inside/outside air suction FOOT mode in a modification of a suction port switching door of an embodiment of the present invention. 
           [0031]      FIG. 5  is a cross-sectional view of an air-conditioning unit of an embodiment of the present invention. 
           [0032]      FIG. 6(   a ) is an explanatory view which shows another embodiment of an outside air flow adjustment mechanism, while  FIG. 6(   b ) is a schematic view which shows an iris shutter type throttling door  75 . 
           [0033]      FIG. 7  is an explanatory view which shows another embodiment of an outside air flow adjustment mechanism (at time of inside/outside air suction FOOT mode). 
           [0034]      FIG. 8  is an explanatory view which shows another embodiment of an outside air flow adjustment mechanism (at time of inside/outside air suction FOOT mode). 
           [0035]      FIG. 9  is an explanatory view which shows another embodiment of an outside air flow adjustment mechanism. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0036]    The present invention will be understood more clearly while considering the description of embodiments of the present invention given with reference to the attached drawings as explained below. Below, embodiments of the present invention will be explained with reference to the drawings. In the embodiments, parts of the same configuration are assigned the same reference notations and their explanations are omitted. Parts of the same configuration as the prior art as well are assigned the same reference notations and their explanations are omitted.  FIG. 2  is a schematic explanatory view of an inside/outside air suction FOOT mode in an embodiment of the present invention.  FIG. 3  is a schematic explanatory view of an outside air suction FOOT mode in an embodiment of the present invention.  FIG. 4  is a schematic explanatory view of an inside/outside air suction FOOT mode in a modification of a suction port switching door of an embodiment of the present invention. The vehicular air-conditioning system of the present invention is divided into two parts: an air-conditioning unit  10  and a blower unit  9  which blows air to this air-conditioning unit  10  and the units are called HVAC. The blower unit  9  has a two-layer structure capable of blowing inner and outer air in a two-layer state. 
         [0037]    The suction port switching door which opens and closes the air introduction port is comprised of an inside air switching door  67  which is provided at the inside air introduction port  65 , an outside air switching door  68  which is provided at the outside air introduction port  66 , and an inside/outside air switching door  69 . It is possible to set three modes: an inside/outside air suction mode ( 67 : open,  68 : open,  69 : close), outside air mode ( 67 : close,  68 : open,  69 : open), and inside air mode ( 67 : open,  68 : close,  69 : open). The outside air enables a defogging performance to be secured for the windshield, so it becomes possible to suitably select the mode according to the case. The suction port switching door is not necessarily limited to the embodiment of  FIG. 2 .  FIG. 4  shows a modification of the suction port switching door of the present embodiment. In  FIGS. 4 ,  65 - 1  and  66 - 1  are outside air introduction ports, while  65 - 2  and  66 - 2  are inside air introduction ports. The switching doors  67 ′,  68 ′ can be operated to realize the inside/outside air suction mode, outside air mode, and inside air mode. There are also various modes other than these (as one example, see PLT 2). 
         [0038]    The centrifugal blower  8  of the blower unit  9  is comprised of an upper fan  52  and a lower fan  53 . Here, the embodiments are not limited to the definitions of “upper” and “lower” in the upper fan” and the “lower fan”. In the inside/outside air suction FOOT mode which is shown in  FIG. 2 , the outside air runs from the outside air introduction port  66  through the first introduction passage  71  and passes through the filter  90  to be sucked in from the top introduction port  91  to the upper fan  52 . After that, it is communicated through the first discharge passage  81  to the defroster vents  26  and face vents  28 . The inside air runs from the inside air introduction port  65  through the second introduction passage  70  and passes the filter  90  to be sucked in from the bottom introduction port  92  to the lower fan  53 . After that, it is communicated through the second discharge passage  82  to the foot vents  30 . 
         [0039]    The first introduction passage  71  is provided with a throttling door  72 , so outside air is blown throttled to the defroster vents  26  and face vents  28 . Even if the vehicle speed becomes high and the ram pressure of the introduced outside air rises, the throttling door  72  can be adjusted to adjust the flow rate of air which is blown from the defroster vents  26  and face vents  28 . Due to this, even if not opening the defroster door  27  and face door  28  slightly, it is possible to linearly adjust the flow rate of air which flows through the upper side. For this reason, it is possible to keep down the occurrence of a whistling sound due to the slight door opening while adjusting the flow rate of air to a suitable level in response to an increase in the flow rate of air due to the ram pressure at the time when the vehicle is moving at a high speed without detracting from comfort. 
         [0040]    The first discharge passage  81  and the second discharge passage  82  of the blower unit  9  are partitioned by the top/bottom passage partitioning member  73  and continue up to just before the evaporator  12  of the air-conditioning unit.  FIG. 5  is a cross-sectional view of an air-conditioning unit of an embodiment of the present invention. Explanations of parts assigned the same reference notations as in  FIG. 1(   a ) are omitted. Unlike  FIG. 1(   a ), there is no first switching door  23 . The first upstream side partition member is set at a position dividing the cross-sectional area into about half each for the top and bottom passages. This air-conditioning unit gives one example. The invention is not limited to this. Various modifications are included in the present invention. In an air-conditioning unit of one embodiment of  FIG. 5 , the air mix doors  20  and  21  are made sliding doors, but pivoting doors may also be used. There are various embodiments for the air mix doors and passage routes. 
         [0041]    The passage inside the blower unit (HVAC) is partitioned by the first upstream partitioning member  15  and first downstream partitioning member  22  into an upper (outside air side) air passage and lower (inside air side) air passage. From the FOOT vent  30 , high temperature inside air which is warmed by sucking in air at the inside air introduction port  65  is recycled and blown out. On the other hand, from the defroster vents  26  and face vents  28 , low humidity warm outside air obtained by sucking in air at the outside air introduction port  66  can be blown out. 
         [0042]    Next, referring to  FIG. 3 , the outside air suction FOOT mode will be explained. In this case, the inside air switching door  67  which is provided at the inside air introduction port  65  is closed, while the outside air switching door  68  which is provided at the outside air introduction port  66  is opened. The inside/outside air switching door  69  is also open. Therefore, outside air is introduced to the first introduction passage  71  and the second introduction passage  70 . A throttling door  72  is set at the first introduction passage  71 , so outside air is blown to the defroster vents  26  and face vents  28  while throttled. In the FOOT mode, the air flow which strikes the faces of the driver and passengers is prevented from becoming greater. Outside air is blown to the second introduction passage  70  without being throttled, but is communicated with the foot vents through the second discharge passage  82  and blown to the foot parts, so even if the flow rate of air increases, it does not become that much of a problem. 
         [0043]    The present embodiment exhibits its advantageous effects in the FOOT mode. Here, there are various variations in the type of the FOOT mode.  FIG. 1(   b ) shows one example of the FOOT mode. Such a FOOT mode is also possible. In the present embodiment, some air is blown from the defroster vents  26  and face vents  28  as well. Of course, the invention is not limited to this. So long as a mode which mainly distributes the air to the FOOT vents  30  (in the present application, this mode called as “FOOT mode”), the advantageous effects of the present embodiment are exhibited. In addition, even in the F/D mode, the advantageous effect arises that the outside air is blown while throttled. 
         [0044]    In the present embodiment, the throttling door  72  is set in front of the top introduction port  91  of the upper fan  52 , so it is possible to adjust the air flow rate to a suitable level in response to an increase in the air flow rate due to the ram pressure when the vehicle is moving at a high speed without detracting from comfort. Further, it is possible to reduce the amount of work which is imposed on the fan, so along with a reduction in noise, an unexpected energy saving effect arises. 
         [0045]      FIG. 6(   a ) is an explanatory view which shows another embodiment of an outside air flow adjustment mechanism, while  FIG. 6(   b ) is a schematic view which shows an iris shutter type throttling door  75 . It is possible to change the diameter of the circular hole  76  at the center part of the plurality of blades  77  and make it function as a throttling door. It may be set at the bell mouth part of the top introduction port  91  of the upper fan  52 . The flow rate of air which flows through the first discharge passage  81  and the upper (outside air side) air passage is linearly adjusted. Due to this, it is possible to adjust the air flow rate to a suitable level in response to an increase in the air flow rate due to the ram pressure without detracting from comfort. 
         [0046]      FIGS. 7 and 8  are explanatory views which show other embodiments of an outside air flow adjustment mechanism.  FIG. 7  shows an embodiment which provides a throttling door  78  in the first discharge passage  81  from the upper fan  52  to the evaporator  12 . In another embodiment of an outside air flow adjustment mechanism of  FIG. 8 , an opening/closing door  79  is provided at the top/bottom passage partitioning member  73  between the first discharge passage  81  from the upper fan  52  to the evaporator  12  and the second discharge passage  82  from the lower fan  53  to the evaporator  12 . The opening/closing door  79  pivots to the first discharge passage side, so it is possible to throttle the flow rate of air passing through the first discharge passage  81 . Due to this, it is possible to adjust the air flow rate to a suitable level in response to an increase in the air flow rate due to the ram pressure without detracting from comfort. 
         [0047]      FIG. 9  is an explanatory view which shows another embodiment of an outside air flow adjustment mechanism. The variable nose part clearance mechanism  83  which is provided at the nose part of the upper fan  52  is used to adjust the clearance between the nose part and the outer circumference of the fan blades  84 . If greatly increasing the clearance between the nose part and the outer circumference of the fan blades, the fan spins idly and the amount of blown air is reduced. Due to this, it is possible to adjust the air flow rate to a suitable level in response to an increase in the air flow rate due to the ram pressure without detracting from comfort. The variable nose part clearance mechanism  83  rocks in  FIG. 9  to adjust the amount of clearance, but the invention is not limited to this. It may also be made to linearly move. Since the fan spins idly whereby the amount of blown air is reduced and the amount of work is reduced, there is also an energy saving effect. 
         [0048]    The present invention was described in detail with reference to specific embodiments which were selected for the purpose of illustration, but a person skilled in the art could make various modifications without departing from the basic concept of the present invention the range of the disclosure. 
       REFERENCE NOTATIONS LIST 
       [0000]    
       
           9  blower unit 
           10  air-conditioning unit 
           26  defroster vent 
           28  face vent 
           30  foot vent 
           52  upper fan 
           53  lower fan 
           70  second introduction passage 
           71  first introduction passage 
           81  first discharge passage 
           82  second discharge passage