Abstract:
A compressor shaft has a fluid inlet that leads into a fluid inlet tube, which is perpendicular to a longitudinal hole in the length of the shaft. An intermediate inlet into the longitudinal hole is located between the fluid inlet and an outlet at an end of the longitudinal hole. A drive plate mounted to the compressor shaft has a protruding drive arm, which uses a holding mechanism to connect to a swash plate. At certain swash plate angles, the intermediate inlet is covered and sealed by the swash plate, or uncovered. The drive arm defines an internal bore and a through slot. At opposite ends, the bore merges into the longitudinal hole and opens into the through slot. The holding mechanism and/or swash plate guide covers the bore in the slot.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/623,897 filed on Nov. 23, 2009. The entire disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to an oil separator that separates oil from another fluid, such as a refrigerant in a compressor crank case. 
       BACKGROUND 
       [0003]    This section provides background information related to the present disclosure which is not necessarily prior art. Compressors used to compress a refrigerant, such as R134a, in an air-conditioning system of a vehicle are known; however, such compressors are not without their share of limitations. One such limitation is the amount of heat stored within the compressor, which is created and held within a swash plate chamber (i.e. crank case) of a variable displacement air conditioning compressor. Prolonged subjection to heat may decrease the useful life of internal compressor parts and thus the useful life of the compressor. By controlling the volume of lubricating oil that is retained within the swash plate chamber, such as during specific volumes of compressor piston displacement, heat generated within the swash plate chamber may be controlled. 
         [0004]    Another limitation of air conditioning compressors relates to the amount of oil that is permitted to be discharged from the compressor swash plate chamber and become resident within other components of an attached air conditioning refrigeration system, such as within a condenser and an evaporator. Oil that becomes resident in a condenser and an evaporator may decrease the cooling effectiveness of refrigerant passing through such components because a layer of oil within an internal cavity of such components decreases the heat transfer performance of such components and the overall cooling performance of the air conditioning system. What is needed then is a device that is capable of helping to retain oil within the compressor swash plate chamber when the compressor operates at prescribed compressor displacements. 
       SUMMARY 
       [0005]    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 compressor apparatus for use in a vehicle air conditioning compressor may employ a compressor casing that defines a suction chamber, one or more compressor pistons that each define a working chamber with the compressor casing, and a control valve contained within the compressor casing. The control valve may be used for pressure control between the swash plate chamber and working chamber in order to determine a compressor displacement. The compressor apparatus may further employ a compressor shaft that may define an internal, longitudinal through hole from a first shaft end, such as near pulley retaining feature(s) (e.g. splines or threads) of the shaft, to a second shaft end. The longitudinal through hole at the second shaft end may define an outlet that provides fluid access (i.e. an exit) into the suction chamber. 
         [0006]    The compressor shaft may further define a fluid inlet and a fluid inlet tube. The fluid inlet may be proximate the shaft splines and a lip seal, and the fluid inlet tube may be perpendicular to a non-exit end of the longitudinal through hole. The fluid inlet tube may fluidly link the fluid inlet and the longitudinal through hole. The shaft may also have an intermediate inlet located between the fluid inlet at the first shaft end and the fluid outlet at the second shaft end. A drive plate may be mounted to the compressor shaft with a drive arm protruding from the drive plate. A drive arm may further define an internal bore with a first bore end and a second bore end. The first bore end may merge into the longitudinal through hole to permit the flow of fluid (e.g. oil and refrigerant) to flow from the bore to the longitudinal hole and then to the suction chamber. The drive arm may further define a through slot, with the internal bore opening into the through slot. 
         [0007]    The drive arm may also protrude from the drive plate to facilitate connection of a swash plate, which may employ a protruding swash plate guide. A slot in the drive arm may permit a holding mechanism (e.g. pin or shuttle) to secure the swash plate and swash plate guide to the drive plate and the pin is moveable within the slot when the swash plate changes position. The pin may cover the second end of the internal bore and create a seal. Alternatively, the swash plate guide may cover the second end of the internal bore and create a seal to prevent fluid flow into the bore. Still yet, the pin and the swash plate guide may together cover the second end of the internal bore and create a seal to prevent fluid flow into the bore. The intermediate inlet may be located under the swash plate such that the inlet may be sealed by the swash plate. 
         [0008]    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 
         [0009]    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. 
           [0010]      FIG. 1  is a side view of a vehicle depicting locations of various components of a vehicle air conditioning system; 
           [0011]      FIG. 2  is a schematic view of an arrangement of various components of a vehicle air conditioning system; 
           [0012]      FIG. 3  is a cross-sectional view of an air conditioning compressor depicting a hollow shaft in accordance with the present disclosure; 
           [0013]      FIG. 4  is a schematic view of an air conditioning compressor depicting a hollow shaft in accordance with the present disclosure; 
           [0014]      FIG. 5  is an end view of a compressor shaft in accordance with the present disclosure; 
           [0015]      FIG. 6  is a side view of the compressor shaft of  FIG. 5 ; 
           [0016]      FIG. 7  is a side view of the compressor shaft of  FIG. 5 ; 
           [0017]      FIG. 8  is a side view of a compressor shaft depicting a swash plate pin in a first position in accordance with the present disclosure; 
           [0018]      FIG. 9  is a side view of the compressor shaft of  FIG. 8  depicting the swash plate pin in a second position; 
           [0019]      FIG. 10  is a side view of the compressor shaft of  FIG. 8  depicting the swash plate connection in a second position; 
           [0020]      FIG. 11  is a side view of the compressor shaft of  FIG. 8  depicting the swash plate connection in a first position; 
           [0021]      FIG. 12  is a side view of the compressor shaft of  FIG. 8  depicting the swash plate connection and swash plate pin being concurrently positioned in a first position; 
           [0022]      FIG. 13  is a side view of a compressor shaft depicting an intermediate inlet through the shaft wall in accordance with the present disclosure; and 
           [0023]      FIG. 14  is a side view of a compressor shaft depicting an intermediate inlet through the shaft wall in accordance with the present disclosure. 
       
    
    
       [0024]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0025]    Example embodiments of the present teachings will now be described more fully with reference to accompanying  FIGS. 1-14 . Referring initially to  FIG. 1 , a vehicle  10  may include an engine compartment  12  within which part of a heating, venting, and air conditioning (HVAC) system  14 , depicted in phantom, may reside. HVAC system  14  may include an air-conditioning compressor  16 , an HVAC unit  18 , condenser  34  and hoses  20 ,  22  to connect compressor  16  to one or more components within HVAC unit  18 . Vehicle  10  may include a passenger compartment  24 , which HVAC system  14  may cool in a known manner. 
         [0026]    Turning now to  FIG. 2 , an HVAC system  14  represented by a schematic diagram, will be further explained. A refrigeration cycle of HVAC system  14  includes compressor  16  which draws, compresses, and discharges a refrigerant, such as R134a. The power of a vehicle engine  28  may be transmitted to compressor  16  through a pulley  30  and a belt  32  to enable compressor  16  to compress the refrigerant. 
         [0027]    In HVAC system  14 , compressor  16  may discharge a superheated gas refrigerant (e.g. R134a) at a high temperature and a high pressure, which flows into a condenser  34 , where heat exchange is performed with outside (ambient) air  35 , which may be forced by a cooling fan (not shown) so that the refrigerant is cooled before and during condensation. The refrigerant is condensed in condenser  34  then flows into a receiver  36   
         [0028]    The liquid refrigerant from the receiver  36  is expanded by an expansion valve  38  into a gas-liquid double phase state of low pressure refrigerant fluid. The low pressure refrigerant from expansion valve  38  flows into an evaporator  40  by way of an inlet pipe  42 . Evaporator  40  is arranged inside HVAC unit  18  of vehicle HVAC system  14 . The low pressure refrigerant flowing into evaporator  40  absorbs heat from the air  41  inside the HVAC unit  18  as air  41  is passed over evaporator  40 . Outlet pipe  44  of evaporator  40  may be connected to the suction side of compressor  16 , so that the refrigeration cycle components mentioned above constitute a closed fluid circuit. 
         [0029]    HVAC unit  18  forms a ventilation duct through which air conditioning air is sent into passenger compartment  24 . HVAC unit  18  may contain a fan  46  that is arranged on the upstream side of the evaporator  40 . An inside/outside air switch box (not shown) may be arranged on the suction side of fan  46 , that is, the left side of fan  46  in  FIG. 2 , such that the air inside passenger compartment  24  (inside air) or the air outside passenger compartment  24  (outside air) may be alternated or mixed and introduced through the inside/outside air switch box and into the HVAC unit  18  by fan  46 . 
         [0030]    HVAC unit  18  accommodates, on the downstream side of evaporator  40 , a hot water heater core (heat exchanger)  48 , which may employ an inlet pipe  50  and an outlet pipe  52 . Hot water (coolant) of vehicle engine  28  may be directed to heater core  48  through inlet pipe  50  by water pump  53 . A liquid valve may control the flow volume of engine coolant supplied to the heater core  48  while a radiator  54  and a thermistor  56  further cooperate to control the temperature of the circulating liquid coolant. 
         [0031]    A bypass channel  58  may be formed beside the hot water heater core  48  while an air mix door  60  may be provided to adjust the volume ratio between warm air and cool air that passes through the hot water heater core  48  and the bypass channel  58 , respectively. Air mix door  60  may adjust the temperature of the air blown into passenger compartment  24  by adjusting the volume ratio between the warm air and cool air. 
         [0032]    Additionally, a face outlet  62 , a foot outlet  64 , and a defroster outlet  66  are formed at the downstream end of the HVAC unit  18  such that face outlet  62  may direct air toward the upper body portions of passengers, foot outlet  64  may direct air toward the feet of the passengers, and defroster outlet  66  may direct air toward the internal surface of a vehicle windshield. Outlets  62 ,  64 ,  66  may be opened and closed by outlet mode doors (not shown). Air mix door  60  and the outlet mode doors mentioned above may be driven by such electric driving devices such as servo motors via linkages or the like. 
         [0033]    With reference now including  FIG. 3 , compressor  16  is depicted in a cross-sectional view. As depicted, compressor  16  may be a swash plate type of variable displacement compressor. Compressor  16  may employ a front housing  70 , a middle housing  72 , and a rear housing  74 , which all may be joined together by bolts, for example. A shaft  76  may pass through and be centered in a central portion of a swash plate chamber  78  defined by front housing  70 , middle housing  72 , and rear housing  74 . Shaft  76  may serve as an input shaft with a drive plate  80  (also known as a lug plate) attached to shaft  76 . A generally disk-shaped swash plate  82  may be loosely or pivotably installed around shaft  76  so as to be able to freely tilt or pivot with respect to the shaft  76 , while also contacting shaft  76 . Shaft  76  and swash plate  82  may freely rotate within swash plate chamber  78  and may cause one or more pistons  84  to reciprocate parallel to shaft  76  within cylinders  86 , which are defined in part by middle housing  72  and rear housing  74 . As an example, as many as six pistons  84  may be provided at equal or unequal intervals around the shaft  76 . Swash plate chamber  78 , also called a “control pressure chamber” may accommodate swash plate  82 , and be formed in the area of the front housing  70  as a closed space. 
         [0034]    Continuing with  FIG. 3 , a semispherical shoe  88  may fit into a corresponding semispherical recess formed in the end of each piston  84  and facilitate movement of each piston  84  with a corresponding periphery of swash plate  82 . Alternatively, each semispherical shoe  88  may have one or more flat surfaces that abut a corresponding flat surface on a corresponding piston to facilitate piston movement. An arm  90  may be attached to and project out and away from drive plate  80 . Swash plate  82  may further project out to arm  90  with an arm-like guide  92  provided with a guide surface  94  at its end to engage a surface  96  defined on end of arm  90 . A thrust bearing  98  may support shaft  76  through drive plate  80  in the axial direction. Radial bearings (not shown) may be used to support shaft  76  in the radial direction. Continuing with  FIG. 3 , working chamber  100  may be formed by a flat surface or face  102  of piston  84  and either middle housing  72 , or rear housing  74 , for example, for compressing a fluid, such as a refrigerant (e.g. R134a) for an air-conditioning system. 
         [0035]      FIG. 4  is a schematic depicting compressor  16  utilizing a lug plate or drive plate  80  that is slightly different than that depicted in  FIG. 3 , while  FIG. 4  depicts further details of shaft  76 . More specifically, shaft  76  may define a longitudinal hole  104  or bore through its entire longitudinal length, or part of its longitudinal length. Longitudinal hole  104  may exist within shaft  76  from adjacent or near shaft splines  106  at front housing  70  to an opposite end of compressor  16  at rear housing  74 . Hole  104  may pass through an end of shaft  76  at an end of shaft opposite splines  106 , which may secure pulley  30  to shaft  76 . Longitudinal hole  104  may be centered through shaft  76  and at front housing  70 , an inlet hole  110  and an inlet tube  108  may provide access from swash plate chamber  78 . Inlet tube  108 , may be chamfered or beveled to facilitate entry of oil (e.g. crankcase oil) and gas (e.g. refrigerant gas) of an oil rich area of swash plate chamber  78 . From inlet hole  110 , fluid may flow into inlet tube  108  and subsequently hole  104 . Inlet tube  108  may be perpendicular to hole  104  and meet hole  104  at a right angle at an end of hole  104 . 
         [0036]    Continuing with reference to  FIG. 4 , upon oil and/or gas (“fluid”) entering inlet  110  and traveling the entire length of hole  104 , such fluid will exit hole  104  at outlet  112  and flow into a suction chamber  114 . Accumulated fluid within suction chamber  114  may then be drawn back into working chambers  100  for compression by pistons  84  upon opening of chamber valves (not depicted). A control valve  116  ( FIG. 3 ) may be confined within rear housing  74  and controlled to change the discharge capacity of compressor  16 . 
         [0037]    Additionally, fluid will flow into suction chamber  114  from compressor suction inlet  118  ( FIG. 3 ) in accordance with arrow  121 . Fluid in suction chamber  114  is drawn into working chambers  100  as one or more pistons  84  reciprocate. After being drawn into suction chamber  114  and undergoing compression in working chamber  100 , a majority of the compressed fluid is forced out of compressor  16  via compressor discharge outlet  120  ( FIG. 3 ). However, due to the compression of fluid by pistons  84  in working chamber  100 , some fluid does not exit working chamber  100  via compressor discharge outlet  120 , but rather by becoming “blow by”  122 , which is the passage of fluid (e.g. refrigerant and oil) between an outside diameter of piston  84  and inside diameter of cylinder  86 . Such blow by  122  discharges directly into swash plate chamber  78  and results in an accumulation of oil and refrigerant in swash plate chamber  78 . The control valve  116  may also permit fluid from different circuits to enter the swash-plate chamber as well. 
         [0038]    Droplets of oil and refrigerant may be continuously suspended in the atmosphere within swash plate chamber  78 , at least while compressor  16  is rotating or being driven by pulley  30  via belt  32  ( FIG. 2 ). Moreover, because shaft  76  and drive plate  80  rotate to invoke reciprocation of pistons  84  within cylinders  86 , oil that accumulates on such rotating parts may be flung or transferred to the interior surfaces or walls of front housing  70 , middle housing  72  and rear housing  74 . The accumulation of oil on interior surfaces of front housing  70 , middle housing  72  and rear housing  74  may be used in such a way to increase the cooling performance of HVAC system  14 . Additionally, by manipulating the amount of oil within compressor  16 , the useful life of compressor  16  may be extended. 
         [0039]      FIG. 4  depicts how oil may be deposited on interior walls of compressor casing and compressor structure to redistribute accumulated oil. More specifically,  FIG. 4  depicts front housing  70 , middle housing  72  and rear housing  74  of compressor  16  with an accumulated layer of oil  124  on interior surface of front housing  70  and a layer of accumulated oil on interior surface of middle housing  72 . When shaft  76  and drive plate  80  rotate causing oil to accumulate as layers of oil  124 ,  126 , the atmosphere within swash plate chamber  78  may become laden with oil. In other words, atmosphere  128  within swash plate chamber  78  may become an atmosphere misty with oil and refrigerant. Although volumes of swash plate chamber  78  laden with oil are represented by atmospheres  128  in  FIG. 4 , in actuality, the entire swash plate chamber  78  may be laden or misty with oil. 
         [0040]    Pump structure and pump operation to aid in redistribution of layers of oil  124 ,  126  and oil laden atmosphere  128  will now be presented.  FIG. 4  depicts drive plate  80  with an arm  90  defining a slot  130  in arm  90 . Slot  130 , as depicted in  FIG. 4 , may not be parallel to shaft  76 , and more specifically, slot  130  may have a slot end  132  that is farther from shaft  76  than a slot end  134 . Additionally, slot end  132  may be closer to end of shaft  76  that retains pulley  30  than slot end  134 . A bore  136  or orifice may reside within drive plate  80  and shaft  76  such that bore  136  creates a fluid path from longitudinal hole  104 , through drive plate  80  and into arm  90  such that bore  136  opens to swash plate chamber  78  at an end opposite that end opening into longitudinal hole  104 . Bore  136  is for transfer of oil and refrigerant resident within swash plate chamber  78 , as will be explained later. A pin  138  may traverse within slot  130  while also securing swash plate  82  to drive plate  80 . 
         [0041]      FIGS. 5-7  present a slightly different embodiment of a drive plate and accompanying arm. More specifically, drive plate  150  may have an arm  152  that protrudes away from drive plate  150  such that a slot  154  within arm  152  has a slot first end  156  that is closer to an end of shaft  76  that retains pulley  30  ( FIG. 2 ) while a slot second end  158  lies farther away from an end of shaft  76  that retains pulley  30 . Moreover,  FIGS. 5-7  depict an embodiment such that an arm end  160  of arm  152  that is the farthest protruding end of arm  152 , protrudes from drive plate  150  such that arm end  160  is farther from shaft  76  than any other portion of arm  152 . A bore  162  permits fluid communication between longitudinal hole  104  and slot  154 . 
         [0042]    Turning now to  FIG. 8 , operation of compressor shaft  76  in conjunction with drive plate  80  and a corresponding swash plate  164  will be discussed. For ease of depiction regarding  FIG. 8 , the entire outer casing, or front housing  70 , middle housing  72 , and rear housing  74 , of compressor  16  has been removed; however,  FIG. 4  depicts a smaller scale view including front housing  70 , middle housing  72 , and rear housing  74 , along with corresponding oil deposition on such housings and in the volume contained by such housings  70 ,  72 ,  74 . Continuing,  FIG. 8  depicts a swash plate  164  with a swash plate guide  166  protruding from swash plate  164  at a particular angle to swash plate  164 . 
         [0043]    With continued reference to  FIG. 8 , during operation of compressor  16 , such as during maximum displacement of pistons  84  ( FIG. 3 ), which may be evidenced by an angle that swash plate  164  forms with and relative to drive plate  80 , swash plate guide  166  will move in accordance with pin  168  that couples or is attached to swash plate guide  166  and that also passes through slot  130  in arm  90  of drive plate  80 . As pin  168  moves within slot  130 , an end  170  of bore  136  may become covered and uncovered by pin  168  depending upon the displacement of pistons  84  as determined by cooling capacity desired. When end  170  of bore  136  becomes uncovered, fluid  172  indicated with arrows, is able to enter bore  136 , flow into and through longitudinal hole  104  and into suction chamber  114  ( FIG. 3 ). Alternatively, as depicted in  FIG. 9 , pin  168  may cover bore end  170 , such as during reciprocation when swash plate  164  is at an angle with drive plate  80  that is different than that depicted in  FIG. 8 . Moreover, when end  170  of bore  136  is covered, the displacement of pistons  84  within compressor  16  is also different than that of  FIG. 8 . Thus, when end  170  of bore  136  is covered, fluid within swash plate chamber  78  is prevented from flowing into bore  136 , which may cause fluid within swash plate chamber  78  to enter inlet  110 , flow through inlet tube  108  and into longitudinal hole  104  and then into suction chamber  114  ( FIG. 3 ). 
         [0044]    While fluid (e.g. refrigerant and/or oil) may eventually enter longitudinal hole  104  via bore  136  or inlet tube  108 , there is an advantage to fluid entering hole  104  via bore  136  at any given instances. Cooling performance of a vehicle air conditioning system may be maximized when oil from swash plate chamber  78  is maintained within swash plate chamber  78  and not distributed throughout air conditioning system, such as into condenser  34  and evaporator  40  after being compressed with refrigerant. More specifically, when lubricating oil within swash plate chamber  78  is drawn into suction chamber  114  and subsequently working chambers  100  of compressor  16 , such oil is mixed with the refrigerant gas (e.g. R134a) of the air conditioning system and compressed. Upon compression, the oil and gas mixture is forced into condenser  34  and evaporator  40  and every other refrigerant passage of HVAC system  14 . Because oil creates a liquid layer on the inside of all fluid passages, including condenser  34  and evaporator  40 , such oil acts as a barrier that reduces the heat transferring performance of condenser  34  and evaporator  40 . Thus, air conditioning cooling performance is reduced when oil is entering suction chamber  114  during operation of compressor  16 . Thus, lowering the amount of oil entering suction chamber  114  at any given time, will improve cooling performance of HVAC system  14 . Because maximum cooling performance, that is, the ability to provide the maximum amount of cooled or chilled air to a passenger compartment  24 , is desired during periods of maximum or high compressor displacement (during maximum stroke of compressor pistons  84 ), reducing by as much as possible the volume of oil entering suction chamber  114  from swash plate chamber  78  is desirable. By reducing the volume of oil entering suction chamber  114  from swash plate chamber  78  and subsequently condenser  34  and evaporator  40 , improved cooling may be experienced by HVAC system  14 . Moreover, by retaining as much oil as possible within swash plate chamber  78 , in comparison to a volume of oil that is drawn from swash plate chamber  78  and into suction chamber  114 , the useful life of compressor  16  may also be extended since oil is a lubricant which reduces friction between compressor parts in contact. 
         [0045]    During operation of compressor  16 , as depicted in  FIG. 4 , liquid oil may coat or be deposited as layers of oil  124 ,  126  on compressor housings  70 ,  72 ,  74 . Atmosphere  128  may be a blend of oil mist and refrigerant, but the concentration of oil may be less than deposited layers of oil  124 ,  126 . As depicted in  FIG. 8 , when compressor  16  is undergoing high displacements, such as when maximum or near maximum cooling capacity is required, end  170  of bore  136  becomes uncovered and permits suction from “oil poor” atmosphere  128  and generally, swash plate chamber  78 . As stated previously, because atmosphere  128  has a lower concentration of oil than layers of oil  124 ,  126 , atmosphere drawn into hole  104  will be less laden with oil and thus, less oil will be drawn into suction chamber  114  from swash plate chamber  78  and subsequently, discharge outlet  120 , condenser  34 , and evaporator  40 , thus improving heat transfer away from condenser  34  and evaporator  40  and thereby improving cooling performance of the HVAC system  14 . Less oil is drawn into hole  104  because less oil is drawn in from “oil rich” areas  124 ,  126 , such as at inlet  110  where oil is likely to fall onto shaft  76  after being flung on interior surface of the compressor casing. However, when piston displacement is reduced from a maximum or high displacement, to such as that depicted in  FIG. 9 , pin  168  may cover end  170  of bore  136  and permit suction chamber  114  to draw from inlet  110  proximate or near “oil rich” area  124 ,  126 , as indicated by arrows  174 . Gravity may cause liquid oil to drip from areas  124 ,  126  onto or near inlet  110 . An advantage of drawing oil and refrigerant at inlet  110 , such as during high speeds (e.g. maximum compressor speed or that speed set as a maximum, but at a piston displacement that is less than maximum) is that oil will be removed from swash plate chamber  78  and thus permit less heat to be retained by compressor  16 . By retaining less heat, the useful life of compressor  16  may be extended. When compressor  16  is drawing fluid via inlet  110 , compressor  16  may be reciprocating at a displacement that is less than maximum although compressor speed may be at a maximum or near maximum. Thus, because compressor displacement is not at a maximum or at most, near a maximum, maximum cooling performance in terms of oil in condenser  34  and evaporator  40  may not be as important. 
         [0046]    Turning now to  FIGS. 10-11 , another embodiment of the teachings will be presented.  FIGS. 10-11  depict a structure similar to that depicted in preceding figures; however,  FIGS. 10-11  depict a structure in which swash plate guide  166 , also known as a swash plate connection, may open (i.e. uncover) and close (i.e. cover) end  170  of bore  136  to permit or not permit the flow of fluid to longitudinal hole  104  as swash plate reciprocates to cause pistons  84  to move within cylinders  86 . In order to achieve covering and uncovering of end  170  of bore  136 , the angle at which swash plate guide  166  makes with swash plate  164 , such as in the side views depicted in  FIGS. 10-11 , may be different than that depicted in  FIGS. 8-9 , when only pin  168  is used to cover and uncover end  170 . 
         [0047]      FIG. 12  depicts another embodiment in which pin  168  and swash plate guide  166  both, as opposed to individually as discussed above, may be used to cover and uncover end  170  of bore  136  to control the flow of fluid (i.e. oil and refrigerant) to longitudinal bore  104  and subsequently suction chamber  114 . Similar to a prior embodiment, the angle at which swash plate guide  166  makes with swash plate  164 , such as in the side view depicted in  FIG. 12 , may be different than that depicted in  FIGS. 8-11 , to achieve covering and uncovering of bore  136  at end  170  by pin  168  and swash plate guide  166 . 
         [0048]    Turning now to  FIG. 13 , an intermediate inlet  176  is present between inlet  110  and suction chamber  114 . More specifically, intermediate inlet  176  is located in the path of travel of swash plate  164  such that swash plate  164  is cable of covering intermediate inlet  176  so that fluid is not able to flow into or out of intermediate inlet  176 . Continuing, when swash plate  164  reciprocates to move pistons  84 , swash plate  164  may pivot using pin  168  within slot  130  and also move in accordance with arrows  178 ,  180 . Movement by swash plate  164  will cause the covering and uncovering of intermediate inlet  176  by a wall or surface  182  of swash plate  164 . When intermediate inlet  176  is covered, fluid will not flow into intermediate inlet  176  and when inlet is not covered, fluid may flow into intermediate inlet  176 .  FIG. 13  depicts a position of swash plate  164  that during reciprocation permits maximum or near maximum displacement of pistons  84  and also uncovers intermediate inlet  176 . When intermediate inlet  176  is uncovered, oil is permitted to enter intermediate inlet  176  from oil poor area  128  of swash plate chamber  78 , as indicated by arrows  184 . That is, when uncovered, intermediate inlet  176  will draw as little oil as possible into longitudinal bore  104  so that oil remains in swash plate chamber  78 , and does not coat or build up on internal passages of condenser  34  and evaporator  40  to hinder heat transfer during maximum or near maximum displacement of compressor  16 , as previously described. As depicted in  FIG. 13 , inlet  110  may be open at the same time as intermediate inlet  176 ; however, because intermediate inlet  176  is closer to suction chamber  114  than inlet  110 , intermediate inlet  176  represents an inlet of greater suction force and thus, suction is more likely to take place at intermediate inlet  176  than inlet  110 . 
         [0049]      FIG. 14  depicts intermediate inlet  176  being covered by wall  182  of swash plate  164  when swash plate  164  is located over, that is, against a perimeter of, intermediate inlet  176 . More specifically, surface of wall  182  of swash plate  164  effectively creates a seal around intermediate inlet  176  such that fluid is not able to flow into intermediate inlet  176 . Relative to position of swash plate  164  depicted in  FIG. 13 , swash plate  164  depicted in  FIG. 14  is positioned to invoke less displacement of pistons  84 , and as a result, swash plate  164  may be positioned over intermediate inlet  176 . Thus, fluid  174  may be drawn into inlet  110 , beside lip seal  186  ( FIG. 3 ) which is an oil rich area. Thus, because compressor displacement is not at maximum or high in  FIG. 14 , drawing oil and refrigerant from an “oil rich” area of swash plate chamber  78  is acceptable, and thus fluid  174  in the form of oil and refrigerant is drawn into inlet  110 , while intermediate inlet  176  is closed or sealed to effectively prevent drawing or suction at intermediate inlet  176 . 
         [0050]    Further explanation of operation of a vehicle air conditioning system, including adjustment of a variable displacement, swash plate type of air conditioning compressor, may be found in U.S. Pat. No. 6,863,503, which is herein incorporated by reference. 
         [0051]    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 invention. 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 invention, and all such modifications are intended to be included within the scope of the invention.