Patent Publication Number: US-2013231036-A1

Title: Air conditioning system for motor vehicles

Description:
FIELD OF THE INVENTION 
     The present invention relates to an air conditioning system for motor vehicles and, more particularly, to an air conditioning system for motor vehicles in which a warm air flowing through a warm air path is bypassed toward a defrost vent such that a cold air flowing through a cold air path can be partially admitted into a vehicle room during the process of increasing the temperature of the upper region of the vehicle room, thereby preventing a phenomenon that the temperature of the upper region of the vehicle room grows too high and a phenomenon that the vehicle room environment becomes unpleasant. 
     BACKGROUND OF THE INVENTION 
     A motor vehicle is provided with an air conditioning system for cooling or warming a vehicle room. As shown in  FIG. 1 , an air conditioning system includes an air conditioner case  10  within which a main flow path  12  is formed. An indoor air or an outdoor air fed from a blower (not shown) flows through the main flow path  12 . An evaporator  12   a  is installed within the main flow path  12 . The evaporator  12   a  serves to cool the air flowing along the main flow path  12 . 
     The main flow path  12  is bifurcated into a cold air path  14  and a warm air path  16 . A heater core  16   a  is installed within the warm air path  16 . A temperature control door  18  is arranged at a bifurcating point of the cold air path  14  and the warm air path  16 . The cold air cooled by the evaporator  12   a  passes through the cold air path  14 . The warm air heated by the heater core  16   a  passes through the warm air path  16 . 
     The temperature control door  18  is swung between the cold air path  14  and the warm air path  16  to adjust the opening degree of the cold air path  14  or the warm air path  16 , thereby controlling the amount of the cold air or the warm air supplied into the vehicle room. 
     The warm air path  16  is configured such that the downstream end portion  16   b  thereof can be merged with the cold air path  14 . Thus, the warm air flowing along the warm air path  16  and the cold air flowing along the cold air path  14  are combined together and are mixed with each other. The mixed air is supplied into the vehicle room through individual vents  20 ,  22  and  24  while maintaining an appropriate temperature. In the following description, the merging point of the warm air path  16  and the cold air path  14  will be referred to as air mixing area A. 
     The conventional air conditioning system referred to above has a drawback in that the mixing efficiency of the cold air and the warm air in the air mixing area A becomes lower due to the difference in wind velocity and air density between the cold air flowing through the cold air path  14  and the warm air flowing through the warm air path  16 . For that reason, the cold air and the warm air admitted into the air mixing area A are not mixed with each other. This poses a problem in that the cold air and the warm air flow in an unmixed laminar state. 
     In particular, the cold air and the warm air differing in velocity and density from each other are collided with and pushed against each other when they are admitted into the air mixing area A. In this process, the cold air coming from the cold air path  14  is lopsided toward a defrost vent  20  existing near the cold air path  14 . The warm air coming from the warm air path  16  is lopsided toward a floor vent  22  existing near the warm air path  16 . 
     This poses a problem in that a large amount of cold air is introduced into the defrost vent  20  existing near the vehicle window and a large amount of warm air is admitted into the floor vent  22  existing near the vehicle floor. Thus, there is a disadvantage that a large amount of cold air is supplied to the upper region of the vehicle room and a large amount of warm air is fed to the lower region of the vehicle room. 
     Therefore, as shown in  FIG. 2 , the upper region of the vehicle room is kept at a low temperature and the lower region of the vehicle room is kept at a high temperature. As a result, a temperature deviation is generated between the upper and lower regions of the vehicle room, thereby significantly reducing the pleasantness in the vehicle room. 
     Many different technologies have heretofore been developed in an effort to solve the problem of temperature deviation generated within the vehicle room. As one example, KR2005-111251A discloses an air conditioning system for motor vehicles. 
     Referring to  FIG. 3 , the air conditioning system disclosed in KR2005-111251A includes a bypass path  20   a  extending from the downstream end portion  16   b  of the warm air path  16  toward the defrost vent  20 . In this air conditioning system, the warm air flowing through the warm air path  16  is partially bypassed into the bypass path  20   a  and then directly supplied to the defrost vent  20 . 
     This enables the warm air to be directly admitted into the defrost vent  20 . It is therefore possible to supply a sufficient amount of warm air to the upper region of the vehicle room, thereby increasing the temperature in the upper region of the vehicle room. This helps reduce the temperature deviation between the upper and lower regions of the vehicle room. 
     The conventional air conditioning system cited above has a structure in which the warm air flowing through the warm air path  16  is directly bypassed toward the defrost vent  20 . For that reason, the warm air of high temperature passing through the heater core  16   a  is directly introduced into the defrost vent  20  without going through the air mixing area A. This poses a problem in that the warm air of high temperature is excessively supplied to the upper region of the vehicle room. 
     Accordingly, there is a drawback that the temperature is unduly increased in the upper region of the vehicle room. In particular, the temperature in the upper region of the vehicle room becomes higher than the temperature in the lower region of the vehicle room. For that reason, instead of the temperature deviation between the upper and lower regions of the vehicle room becoming lower, the temperature distributions are reversed in the upper and lower regions of the vehicle room. This leads to a problem in that the pleasantness in the vehicle room gets even worse. 
     SUMMARY OF THE INVENTION 
     In view of the above-noted problems, it is an object of the present invention to provide an air conditioning system for motor vehicles capable of preventing a warm air of high temperature from being excessively bypassed toward a defrost vent. 
     Another object of the present invention is to provide an air conditioning system for motor vehicles capable of preventing a warm air of high temperature from being excessively supplied to an upper region of a vehicle room. 
     A further object of the present invention is to provide an air conditioning system for motor vehicles capable of preventing an excessive temperature rise in an upper region of a vehicle room. 
     A still further object of the present invention is to provide an air conditioning system for motor vehicles capable of enhancing pleasantness in a vehicle room. 
     In one aspect of the present invention, there is provided an air conditioning system for motor vehicles, including: an air conditioner case; a cold air path defined within the air conditioner case to allow a cold air passing through an evaporator to flow through the cold air path; a warm air path defined within the air conditioner case to allow a warm air passing through a heater core to flow through the warm air path; a temperature control door arranged to swing between the cold air path and the warm air path, the temperature control door configured to control an opening degree of the cold air path and an opening degree of the warm air path to thereby adjust an amount of the cold air flowing through the cold air path and an amount of the warm air flowing through the warm air path; a defrost vent arranged to discharge therethrough the cold air and the warm air toward an upper region of a vehicle room; a bypass duct arranged to bypass a part of the warm air flowing through the warm air path toward the defrost vent, the bypass duct including an inlet aligned with the warm air path and an outlet aligned with the defrost vent; and a cold air introducing means arranged in at least one of the inlet and the outlet of the bypass duct such that a part of the cold air flowing through the cold air path is introduced into the bypass duct through the cold air introducing means. 
     With the air conditioning system according to the present invention, a part of the cold air flowing through the cold air path is introduced into the defrost vent when the warm air flowing through the warm air path is bypassed toward the defrost vent. Unlike the conventional air conditioning system in which only the warm air is bypassed toward the defrost vent, the air conditioning system of the present invention can provide an effect of preventing the warm air of unduly high temperature from being bypassed to the defrost vent. This makes it possible to prevent the warm air of unduly high temperature from being supplied to the upper region of the vehicle room. Accordingly, it is possible to prevent a phenomenon that the temperature of the upper region of the vehicle room grows too high and a phenomenon that the vehicle room environment becomes unpleasant. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects and features of the present invention will become apparent from the following description of preferred embodiments, given in conjunction with the accompanying drawings. 
         FIG. 1  is a side section view showing one conventional air conditioning system for motor vehicles. 
         FIG. 2  is a graph illustrating a temperature difference between individual vents depending on the opening degree of a temperature control door when the conventional air conditioning system is in operation. 
         FIG. 3  is a side section view showing another conventional air conditioning system for motor vehicles. 
         FIG. 4  is a side section view showing an air conditioning system for motor vehicles according to a first embodiment of the present invention. 
         FIG. 5  is a section view taken along line V-V in  FIG. 4 . 
         FIG. 6  is a graph illustrating a temperature difference between individual vents depending on the opening degree of a temperature control door when the air conditioning system of the first embodiment is in operation. 
         FIG. 7  is a view on one exemplary operation of the air conditioning system of the first embodiment, showing the operation of a cold air guide baffle in a cooling mode. 
         FIG. 8  is a view on another exemplary operation of the air conditioning system of the first embodiment, showing the operation of the cold air guide baffle in a heating mode. 
         FIG. 9  is a side section view showing an air conditioning system for motor vehicles according to a second embodiment of the present invention. 
         FIG. 10  is a view on one exemplary operation of the air conditioning system of the second embodiment, showing the operation of a cold air guide baffle in a cooling mode. 
         FIG. 11  is a view on another exemplary operation of the air conditioning system of the second embodiment, showing the operation of the cold air guide baffle in a heating mode. 
         FIG. 12  is a side section view showing an air conditioning system for motor vehicles according to a third embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Certain preferred embodiments of an air conditioning system for motor vehicles according to the present invention will now be described in detail with reference to the accompanying drawings. The same reference symbols as used in describing the prior art will be used to designate the same elements. 
     First Embodiment 
     Prior to describing the features of an air conditioning system for motor vehicles according to the present invention, the general configuration of the air conditioning system will be briefly described with reference to  FIG. 4 . 
     The present air conditioning system includes an air conditioner case  10  within which a main flow path  12  is formed. An evaporator  12   a  is installed within the main flow path  12 . The evaporator  12   a  serves to cool the air flowing along the main flow path  12 . 
     The main flow path  12  is bifurcated into a cold air path  14  and a warm air path  16 . A heater core  16   a  is installed within the warm air path  16 . A temperature control door  18  is arranged at a bifurcating point of the cold air path  14  and the warm air path  16 . The cold air cooled by the evaporator  12   a  passes through the cold air path  14 . The warm air heated by the heater core  16   a  passes through the warm air path  16 . 
     The temperature control door  18  is swung between the cold air path  14  and the warm air path  16  to adjust the opening degree of the cold air path  14  or the warm air path  16 , thereby controlling the amount of the cold air or the warm air supplied into the vehicle room. 
     The warm air path  16  is configured such that the downstream end portion  16   b  thereof can be merged with the cold air path  14 . The cold air path  14  is merged with the warm air path  16  in an air mixing area A where the warm air flowing through the warm air path  16  and the cold air flowing through the cold air path  14  are mixed with each other. The mixed air is supplied into a vehicle room via individual vents  20 ,  22  and  24  while maintaining an appropriate temperature. 
     Next, certain features of the air conditioning system according to the present invention will be described with reference to  FIGS. 4 through 7 . 
     Referring first to  FIG. 4 , the present air conditioning system includes a bypass duct  30  installed to extend from a downstream end portion  16   b  of the warm air path  16  toward a defrost vent  20  across the air mixing area A. 
     The bypass duct  30  includes a bypass path  32  defined therein. The bypass path  32  is provided with an inlet  34  and an outlet  36 . The inlet  34  is aligned with the downstream end portion  16   b  of the warm air path  16  to introduce a part of the warm air discharged from the warm air path  16 . The outlet  36  is aligned with the defrost vent  20  to discharge the warm air toward the defrost vent  20 . 
     With this bypass duct  30 , the warm air introduced from the warm air path  16  into the bypass duct  30  is directly discharged toward the defrost vent  20 . Thus, the warm air flowing through the warm air path  16  can be directly bypassed toward the defrost vent  20  without going through the air mixing area A. 
     This enables a sufficient amount of warm air to be supplied to the upper region of the vehicle room. Therefore, as shown in  FIG. 6 , the temperature in the upper region (defrost region) of the vehicle room becomes higher. As a result, it is possible to reduce the temperature deviation between the upper region (defrost region) and the lower region (floor region) of the vehicle room, thereby enhancing the pleasantness within the vehicle room. 
     The bypass duct  30  is arranged in an internal flow path of an air conditioner case  10 . Preferably, the bypass duct  30  is installed at the center of the internal flow path in the transverse direction of the internal flow path. 
     In case of a dual type air conditioning system capable of cooling and heating the left and right regions of the vehicle room independently of each other, as shown in  FIG. 5 , it is preferred that two bypass ducts  30  are respectively installed in a left flow path  10   a  and a right flow path  10   b  of an air conditioner case  10 . Preferably, the bypass ducts  30  are attached to a central separator  10   c  partitioning the left flow path  10   a  and the right flow path  10   b . More preferably, the bypass ducts  30  are symmetrically attached to the central separator  10   c.    
     Referring back to  FIG. 4 , the inlet  34  of the bypass duct  30  is spaced apart from the downstream end portion  16   b  of the warm air path  16 . Preferably, the inlet  34  of the bypass duct  30  has an upstream end opening spaced apart from the downstream end portion  16   b  of the warm air path  16  with a gap t left between the upstream end opening and the downstream end portion  16   b  such that the upstream end opening of the inlet  24  of the bypass duct  30  communicates directly with the cold air path  14 . In the present embodiment, the upstream end opening of the inlet  34  serves as a cold air introducing means. 
     The reason for forming the bypass duct  30  in this manner is to ensure that a part of cold air flowing through the cold air path  14  is admitted into the inlet  34  of the bypass duct  30  through the upstream end opening. The cold air introduced from the cold air path  14  into the inlet  34  of the bypass duct  30  is mixed with the warm air introduced from the warm air path  16  into the inlet  34  of the bypass duct  30 , thereby slightly reducing the temperature of the warm air flowing through the bypass duct  30 . 
     The reason for mixing a part of the cold air with the warm air is to reduce the temperature of the warm air bypassed toward the defrost vent  20 . This makes it possible to prevent a warm air of unduly high temperature from being supplied to the upper region of the vehicle room. 
     Accordingly, it is possible to solve the problem inherent in the prior art, which is posed due to the supply of a warm air of unduly high temperature to the upper region of the vehicle room. More specifically, it is possible to prevent a phenomenon that the temperature of the upper region of the vehicle room grows too high and a phenomenon that the vehicle room environment becomes unpleasant. 
     The inlet  34  of the bypass duct  30  is formed into such a structure that the cold air flowing through the cold air path  14  can be easily introduced into the bypass duct  30  through the upstream end opening. 
     For example, the upstream end opening of the inlet  34  of the bypass duct  30  is inclined at a specified angle so as to face toward the cold air path  14 . This enables the cold air flowing through the cold air path  14  to be readily introduced into the inlet  34  of the bypass duct  30  through the upstream end opening. 
     As another example, an edge portion  34   b  of the inlet  34  of the bypass duct  30  existing farther from the cold air path  14  may be formed longer than an edge portion  34   a  of the inlet  34  of the bypass duct  30  existing near the cold air path  14 . In this case, the cold air coming from the cold air path  14  impinges against the edge portion  34   b  of the inlet  34  and flows into the inlet  34  of the bypass duct  30  (see  FIG. 7 ). This makes it possible to efficiently introduce the cold air into the inlet  34  of the bypass duct  30  through the upstream end opening. 
     Referring again to  FIG. 4 , the air conditioning system of the present invention further includes a cold air guide baffle  40  arranged in the temperature control door  18 . The cold air guide baffle  40  is installed one surface of the temperature control door  18  in an opposing relationship with the bypass duct  30 , particularly an opposing relationship with the inlet  34  of the bypass duct  30 . In the present embodiment, the cold air guide baffle  40  serves as a cold air introduction amount control means. 
     When the temperature control door  18  is swung, the cold air guide baffle  40  is moved with respect to the inlet  34  of the bypass duct  30 . The cold air guide baffle  40  controls the flow of the cold air introduced from the cold air path  14  into the inlet  34  of the bypass duct  30 . 
     More specifically, as shown in  FIG. 7 , if the temperature control door  18  is swung in such a direction as to open the cold air path  14  in a cooling mode, the cold air guide baffle  40  allows the cold air to flow from the cold air path  14  toward the inlet  34  of the bypass duct  30 , thereby increasing the amount of cold air introduced into the bypass duct  30 . This enables an increased amount of cold air to be introduced into the bypass duct  30 . As a result, it becomes possible to reduce the temperature of the air bypassed toward the defrost vent  20 . This makes it possible to reduce the temperature of the air supplied to the upper region of the vehicle room in the cooling mode, consequently increasing the vehicle room cooling effect. 
     On the contrary, as shown in  FIG. 8 , if the temperature control door  18  is swung in such a direction as to open the warm air path  16  in a heating mode, the cold air guide baffle  40  restrains the cold air from flowing from the cold air path  14  toward the inlet  34  of the bypass duct  30 . This makes it possible to reduce the amount of the cold air introduced into the bypass duct  30 . 
     Thus, only a small amount of cold air is introduced into the bypass duct  30 . As a result, it becomes possible to increase the temperature of the air bypassed toward the defrost vent  20 . This makes it possible to increase the temperature of the air supplied to the upper region of the vehicle room in the heating mode, consequently increasing the vehicle room heating effect. 
     As stated above, the cold air guide baffle  40  serves to, depending on the operation mode of the air conditioning system, increase or decrease the amount of the cold air introduced into the bypass duct  30 . Accordingly, the temperature of the warm air bypassed toward the defrost vent can be actively controlled depending on the operation mode of the air conditioning system. Thus, the temperature of the warm air supplied to the upper region of the vehicle room can be optimally controlled depending on the operation mode of the air conditioning system. This assists in enhancing the pleasantness within the vehicle room. 
     With the present air conditioning system configured as above, a part of the cold air flowing through the cold air path  14  is also introduced into the bypass duct  30  while the warm air flowing through the warm air path  16  is bypassed toward the defrost vent  20  through the bypass duct  30 . Therefore, unlike the conventional air conditioning system in which only the warm air flowing through the warm air path  16  is bypassed toward the defrost vent  20 , it is possible to prevent a warm air of unduly high temperature from being bypassed toward the defrost vent  20 . This makes it possible to prevent a warm air of unduly high temperature from being supplied to the upper region of the vehicle room. It is therefore possible to prevent a phenomenon that the temperature of the upper region of the vehicle room grows too high and a phenomenon that the vehicle room environment becomes unpleasant. 
     Second Embodiment 
       FIG. 9  shows an air conditioning system according to a second embodiment of the present invention. The air conditioning system of the second embodiment includes a cold air introducing cutout portion  50  formed in the outlet  36  of the bypass duct  30 . The cold air introducing cutout portion  50  is formed by partially cutting away the outlet  36  of the bypass duct  30  and is arranged in an opposing relationship with the cold air path  14 . In the present embodiment, the cold air introducing cutout portion  50  serves as a cold air introducing means. 
     A part of the cold air flowing through the cold air path  14  is introduced into the bypass duct  30  through the cold air introducing cutout portion  50 . The cold air thus introduced is mixed with the bypassed warm air flowing through the bypass duct  30 , thereby reducing the temperature of the bypassed warm air flowing through the bypass duct  30 . As a result, it is possible to effectively reduce the temperature of the warm air flowing toward the defrost vent  20 . This makes it possible to effectively reduce the temperature of the warm air supplied to the upper region of the vehicle room. Thus, the environment in the upper region of the vehicle room becomes pleasant. 
     Referring again to  FIG. 9 , the air conditioning system of the second embodiment further includes a second cold air guide baffle  60  arranged in the temperature control door  18 . The second cold air guide baffle  60  is arranged on one surface of the temperature control door  18  in an opposing relationship with the cold air introducing cutout portion  50  of the bypass duct  30 . In the present embodiment, the second cold air guide baffle  60  serves as a cold air introduction amount control means. 
     When the temperature control door  18  is swung, the second cold air guide baffle  60  is moved with respect to the cold air introducing cutout portion  50 , thereby controlling the flow of the cold air introduced into the bypass duct  30  through the cold air introducing cutout portion  50 . 
     As shown in  FIG. 10 , if the temperature control door  18  is swung in such a direction as to open the cold air path  14  in a cooling mode, the second cold air guide baffle  60  allows the cold air to flow from the cold air path  14  toward the cold air introducing cutout portion  50  of the bypass duct  30 , thereby increasing the amount of the cold air introduced into the cold air introducing cutout portion  50 . 
     This enables an increased amount of cold air to be introduced into the bypass duct  30  through the cold air introducing cutout portion  50 . As a result, it becomes possible to reduce the temperature of the air bypassed toward the defrost vent  20 . This makes it possible to reduce the temperature of the air supplied to the upper region of the vehicle room in the cooling mode, consequently increasing the vehicle room cooling effect. 
     On the contrary, as shown in  FIG. 1 , if the temperature control door  18  is swung in such a direction as to open the warm air path  16  in a heating mode, the second cold air guide baffle  60  restrains the cold air from flowing from the cold air path  14  toward the cold air introducing cutout portion  50  of the bypass duct  30 . This makes it possible to reduce the amount of the cold air introduced into the bypass duct  30  through the cold air introducing cutout portion  50 . 
     Thus, only a small amount of cold air is introduced into the bypass duct  30  through the cold air introducing cutout portion  50 . As a result, it becomes possible to increase the temperature of the air bypassed toward the defrost vent  20 . This makes it possible to increase the temperature of the air supplied to the upper region of the vehicle room in the heating mode, consequently increasing the vehicle room heating effect. 
     With the air conditioning system of the second embodiment described above, the cold air flowing through the cold air path  14  is additionally introduced into the bypass duct  30  through the cold air introducing cutout portion  50 . This makes it possible to more effectively reduce the temperature of the warm air bypassed toward the defrost vent  20 . Accordingly, it is possible to more effectively control the temperature of the warm air supplied to the upper region of the vehicle room through the defrost vent  20 , eventually enhancing the pleasantness within the vehicle room. 
     THIRD EMBODIMENT 
       FIG. 12  shows an air conditioning system according to a third embodiment of the present invention. The air conditioning system of the third embodiment includes a branch duct  70  branched from the bypass duct  30 . The branch duct  70  is branched from the bypass duct  30  to face toward a face vent  24 . 
     The branch duct  70  serves to bypass the air flowing through the bypass duct  30  toward the face vent  24 . Thus, a mixture of the warm air and the cold air is also supplied to an intermediate region of the vehicle room existing between the upper region and the lower region. 
     As a result, the intermediate region of the vehicle room is kept at a temperature similar to the temperature of the upper and lower regions of the vehicle room. This makes it possible to minimize the temperature deviation generated between the upper and lower regions and the intermediate region of the vehicle room, consequently enhancing the pleasantness within the vehicle room. 
     While certain preferred embodiments of the invention have been described hereinabove, the present invention is not limited to these embodiments. It is to be understood that various changes and modifications may be made without departing from the scope of the invention defined in the claims.