Abstract:
A heating, venting, and air conditioning (HVAC) system for a vehicle according to the principles of the present disclosure includes a blower, an evaporator, a heater core, and a single door. The blower is operable to blow air. The evaporator is positioned downstream from the blower and is operable to cool air flowing through the evaporator. The heater core is positioned downstream from the evaporator and is operable to heat air flowing through the heater core. The single door is positioned downstream from the heater core and is rotatable to control airflow through the heater core and to direct airflow to at least one of a first outlet and a second outlet.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/468,968, filed on Mar. 29, 2011. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a door for controlling temperature and airflow distribution in a heating, ventilation, and air conditioning system in a vehicle. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     Heating, venting, and air conditioning (HVAC) systems in a vehicle typically include a blower, an evaporator, a heater core, a temperature door, and an airflow door. The blower blows air through the evaporator and the heater core. The temperature door controls the temperature of airflow exiting the HVAC system by adjusting airflow through the evaporator and/or the heater core. The airflow door controls the distribution of airflow exiting the HVAC system by adjusting airflow to various outlets. 
     HVAC systems that include two doors to control temperature and airflow distribution typically include a linkage that couples the two doors. These HVAC systems may be difficult to package in a vehicle due to space constraints, such as those associated with auxiliary HVAC systems. In addition, these systems include a large number of parts, increasing complexity and cost. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     A heating, venting, and air conditioning (HVAC) system for a vehicle according to the principles of the present disclosure includes a blower, an evaporator, a heater core, and a single door. The blower is operable to blow air. The evaporator is positioned downstream from the blower and is operable to cool air flowing through the evaporator. The heater core is positioned downstream from the evaporator and is operable to heat air flowing through the heater core. The single door is positioned downstream from the heater core and is rotatable to control airflow through the heater core and to direct airflow to at least one of a first outlet and a second outlet. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a section view of a heating, venting, and air conditioning (HVAC) system including a first door for controlling temperature and airflow distribution according to the principles of the present disclosure; 
         FIG. 2  is an isometric view of the door shown in  FIG. 1 ; 
         FIG. 3  is a section view of the HVAC system of  FIG. 1  illustrating the first door adjusted to a first position; 
         FIG. 4  is a section view of the HVAC system of  FIG. 1  illustrating the first door adjusted to a second position; 
         FIG. 5  is a section view of the HVAC system of  FIG. 1  illustrating the first door adjusted to a third position; 
         FIG. 6  is a planar view of a second door for controlling temperature and airflow distribution of an HVAC system according to the principles of the present disclosure; 
         FIG. 7  is a planar view of the second door in the direction of arrows  7  shown in  FIG. 6 ; 
         FIG. 8  is a planar view of the second door in the direction of arrows  8  shown in  FIG. 6 ; 
         FIG. 9  is a section view of the second door taken along a line extending between arrows  9  shown in  FIG. 7  and in the direction of the arrows  9 ; 
         FIG. 10  is the section view of  FIG. 9  illustrating the second door adjusted to the first position; 
         FIG. 11  is the section view of  FIG. 9  illustrating the second door adjusted to the second position; and 
         FIG. 12  is the section view of  FIG. 9  illustrating the second door adjusted to the third position; and 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
     Referring to  FIG. 1 , a heating, ventilation, and air conditioning (HVAC) system  10  includes a blower  12 , an evaporator  14 , a heater core  16 , and a door  18 . The blower  12  blows air through the evaporator  14  and the heater core  16 . The evaporator  14  cools air flowing through the evaporator  14 . The heater core  16  heats air flowing through the heater core  16 . The door  18  controls the temperature and distribution of airflow exiting the HVAC system  10 . The HVAC system  10  is an auxiliary or rear HVAC system for a vehicle, however, the door  18  may be included in a primary or front HVAC system for a vehicle. 
     The door  18  controls the temperature by adjusting the amount of airflow through the heater core  16 . The door  18  controls the airflow distribution by adjusting the amount of airflow directed to an outlet  20  and an outlet  22 . The outlet  20  may be a face outlet and the outlet  22  may be a foot outlet. Alternatively, the outlet  20  may be the foot outlet and the outlet  22  may be the face outlet. Additionally, the heater core  16  may be positioned as shown in dashed lines. The location of the face and foot outlets may be independent from the position of the heater core  16 . 
     With additional reference to  FIG. 2 , the door  18  includes a first portion  24 , a second portion  26 , and bosses  28  on opposite sides of the door  18  at the interface between the first portion  24  and the second portion  26 . Components of the door  18  may be integrally formed as a single unit or formed separately and joined together. The first portion  24  and the second portion  26  may be symmetric with respect to a rotational axis of the door  18  extending through the bosses  28 . To this end, the door  18  may be referred to as a dual door, as the first portion  24  and the second portion  26  may resemble opposite facing doors. 
     The first and second portions  24 ,  26  include closed ends  30  and closed sides  32  defining an opening  34  extending through the door  18 . The closed ends  30  of the first and second portions  24 ,  26  may have a round or dome shape. To this end, the door  18  may be referred to as a dual dome door. The closed sides  32  of the first and second portions  24 ,  26  may have a flat pie shape. The opening  34  may extend between the closed ends  30  of the first and second portions  24 ,  26  and between the closed sides  32  of the first and second portions  24 ,  26 . The bosses  28  may not extend through the closed sides  32  to leave the opening  34  undivided between the first and second portions  24 ,  26 . In this regard, the first and second portions  24 ,  26  may be opposite-facing, pie-shaped portions defining a single hollow interior (i.e., the opening  34 ). 
     The first and second portions  24 ,  26  may include ribs  36  and seals  38 . The ribs  36  may be formed on the inner surfaces of the closed ends  30  for structural support. The seals  38  may extend along the edges of the closed ends and sides  30 ,  32  defining the opening  34 . When the door  18  hits a stop, such as an inner surface of a duct, the seals  38  may form a seal with the stop. The seals  38  may be rubber and the remainder of the door  18  may be plastic. 
     In operation, the door  18  may be rotated in the direction of arrows  40  to decrease the temperature of airflow exiting the HVAC system  10  and to direct more airflow to the outlet  20  and less airflow to the outlet  22 . The door  18  may be rotated using an actuator (not shown), such as a servomotor, coupled to the bosses  28  of the door  18 . Rotating the door  18  in the direction of the arrows  40  decreases the temperature of the exit airflow because less air is allowed to flow through the heater core  16 . 
     Conversely, the door  18  may be rotated in the direction of arrows  42  to increase the temperature of airflow exiting the HVAC system  10  and to direct more airflow to the outlet  22  and less airflow to the outlet  20 . Rotating the door  18  in the direction of the arrows  42  increases the temperature of the exit airflow because more air is allowed to flow through the heater core  16 . In this manner, the temperature and distribution of the exit airflow may be adjusted by simply rotating the door  18 . 
     Adjusting the temperature and distribution of the exit airflow using a single door eliminates the need to include multiple actuators driving multiple doors or complex linkages coupling a single actuator to multiple doors. In turn, the number of parts included in the HVAC system  10  and the amount of space required to package the HVAC system  10  in a vehicle are reduced relative to conventional HVAC systems. As a result, the cost and complexity of the HVAC system  10  are reduced relative to conventional HVAC systems. 
     Referring to  FIGS. 3 through 6 , the door  18  may be adjusted to various positions to control the temperature and distribution of airflow exiting the HVAC system  10 . Each position may correspond to a mode of operating the HVAC system  10 . Although only three positions are shown, the door  18  may be adjusted to positions between the three positions, and the positions between the three positions may correspond to transitional phases between the modes. 
       FIG. 3  shows the door  18  adjusted to a first position. When the door  18  is in the first position, the door  18  prevents air from flowing through the heater core  16  or the outlet  22  and allows air to flow around the heater core  16  (i.e., directly from the evaporator  14  to the outlet  20 ) and through the outlet  20 . Arrows  44  represent the airflow through the HVAC system  10  when the door  18  is in the first position. Thus, the door  18  may be adjusted to the first position to provide maximum cooling and to direct all of the exit airflow to the outlet  20 . 
     Additionally, the HVAC system  10  may include a sliding door  46 . The sliding door  46  may be extended when the door  18  is in the first position, as shown in  FIG. 3 , to prevent scrubbing. Scrubbing occurs when heated air between the heater core  16  and the door  18  flows back through the heater core  16  and to the outlet  20 . The sliding door  46  may be retracted when the door  18  is not in the first position to allow air to flow through the heater core  16 . 
       FIG. 4  shows the door  18  in a second position. When the door  18  is in the second position, the door  18  allows air to flow through the heater core  16 , around the heater core  16 , to the outlet  20 , and to the outlet  22 . Arrows  48  represent the airflow through the HVAC system  10  when the door  18  is in the second position. Thus, the door  18  may be adjusted to the second position to provide some heating and to direct the exit airflow to both of the outlets  20 ,  22 . Air flowing through the heater core  16  (i.e., hot air) may flow to the outlet  22 , and air flowing around the heater core  16  (i.e., cold air) may flow to the outlet  20 . The hot and cold air may mix within the door  18  due to their crossing flow paths, and air may bypass the door  18 , which may eliminate temperature stratification. 
       FIG. 5  shows the door  18  in a third position. When the door  18  is in the third position, the door  18  allows air to flow through the heater core  16  and the outlet  22  and prevents air from flowing around the heater core  16  or through the outlet  20 . Arrows  50  represent the airflow through the HVAC system  10  when the door  18  is in the third position. Thus, the door  18  may be adjusted to the third position to provide maximum heating and to direct all of the exit airflow to the outlet  22 . 
     Referring to  FIGS. 6 through 9 , a door  52  may be similar to the door  18  and include additional features to improve the mixing of hot and cold air. The door  52  includes closed sides  54 ,  56 , partially opened sides  58 ,  60 , closed ends  62 ,  64  connecting the closed sides  54 ,  56 , and bosses  66  projecting from the closed sides  54 ,  56  and centered about a rotational axis of the door  52 . The door  52  may be symmetric with respect to a plane extending through the centers of the bosses  66  perpendicular to the closed sides  54 ,  56  and the partially open sides  58 ,  60 . In addition, the closed ends  62 ,  64  may be dome shaped. To this end, the door  52  may be referred to as a dual dome door, as the symmetric portions of the door  52  may resemble two doors having dome-shaped ends. 
       FIG. 7  shows partition portions  68 ,  70  defining openings  72   a  through  82   a  to allow air to flow through the partially open side  58  of the door  52 . When the door  52  is in the second position discussed above with reference to  FIG. 4 , the openings  72   a ,  76   a , and  80   a  may allow cold air to flow out of the door  52 , and the openings  74   a ,  78   a , and  82   a  may allow hot air to flow into the door  52 . Although  FIG. 7  delineates the partition portions  68 ,  70 , the partition portions  68 ,  70  may form a single partition extending between the closed ends  62 ,  64 . 
       FIG. 8  shows the partition portions  68 ,  70  defining openings  72   b  through  82   b  to allow air to flow through the partially open side  60  of the door  52 . When the door  52  is in the second position, the openings  72   b ,  76   b , and  80   b  may allow cold air to flow into the door  52 , and the openings  74   b ,  78   b , and  82   b  may allow hot air to flow out of the door  52 . Thus, the partition portions  68 ,  70  may define hot air channels  74 ,  78 , and  82  respectively extending between the openings  74   a ,  78   a , and  82   a  in the partially open side  58  and the openings  74   b ,  78   b , and  82   b  in the partially open side  60 . The partition portions  68 ,  70  may also define cold air channels  72 ,  76 , and  80  respectively extending between the openings  72   a ,  76   a , and  80   a  in the partially open side  58  and the openings  72   b ,  76   b , and  80   b  in the partially open side  60 . 
       FIG. 9  illustrates a mixing chamber  84  that extends between the closed sides  54 ,  56  and connects the hot and cold air channels  72  through  82 , thereby improving the mixing between hot and cold airflow through the door  52 . As shown in  FIG. 9 , the hot air channel  74  and the cold air channel  76  overlap, and the mixing chamber  84  extends between the overlapping portions of the channels  74 ,  76 . Thus, hot air is allowed to flow from the hot air channel inlet  74   a , through the mixing chamber  84 , and to the cold air channel outlet  76   a . Conversely, cold air is allowed to flow from the cold air channel inlet  76   b , through the mixing chamber  84 , and to the hot air channel outlet  74   b . In this manner, cold air flows into the openings  72   b ,  76   b , and  80   b , hot air flows into the openings  74   a ,  78   a , and  82   a , the hot and cold air mixes in the mixing chamber  84 , and the mixed air flows to the openings  72   a ,  74   b ,  76   a ,  78   b ,  80   a , and  82   b.    
     Referring to  FIGS. 10 through 12 , the door  52  may be used in place of the door  18 , and the door  52  may be adjusted to various positions to control the temperature and distribution of airflow exiting the HVAC system  10 .  FIG. 10  shows the door  52  adjusted to the first position discussed above with reference to  FIG. 3 . When the door  52  in the first position, the door  52  blocks hot airflow from the heater core  16 , blocks airflow to the outlet  22 , and allows cold air to flow directly from the evaporator  14  to the outlet  20 . Cold air may flow through the door  52  via any one of the channels  72  through  82 . 
       FIG. 11  shows the door  52  adjusted to the second position. When the door  52  is in the second position, the door  52  allows cold airflow from the evaporator  14 , hot airflow from the heater core  16 , and mixed airflow to both of the outlets  20 ,  22 . Hot air enters the door  52  through the opening  74   a  of the channel  74  (i.e., the hot air channel), and cold air enters the door  52  through the opening  76   b  of the channel  76  (i.e., the cold air channel). The hot and cold air may mix in the mixing chamber  84 , and the mixed air may flow through the openings  74   b ,  76   a . In this manner, the mixing chamber  84  improves the mixing of hot and cold air flowing through the door  52 . 
       FIG. 12  shows the door  52  adjusted to the third position discussed above with reference to  FIG. 3 . When the door  52  in the third position, the door  52  blocks cold airflow from the evaporator  14 , blocks airflow to the outlet  20 , and allows hot air to flow from the heater core  16  to the outlet  22 . Hot air may flow through the door  52  via any one of the channels  72  through  82 . 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.