Abstract:
An air conditioning system for a vehicle. The air conditioning system has a compressor and an evaporator. The compressor is driven by a vehicle engine and a motor separately operable from the vehicle engine. The evaporator is disposed in a predetermined air passage to cool the air. The air conditioning system comprises an intake door, predicting means and switching means. The intake door is disposed upstream of the air passage and is switched between a first position and a second position. The intake door is arranged to introduce ambient air from outside of the vehicle in the first position and interior air from inside the vehicle in the second position. The predicting means is disposed for predicting a non-operating state of the vehicle engine. The switching means is disposed for switching the intake door to the second position based on a prediction of the predicting means.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a vehicle air conditioner. More particularly, the present invention relates to a vehicle air conditioner with a refrigerant circuit having a compressor that is driven by a vehicle drive source, or an engine, and an electric motor portion.  
           [0002]    To improve fuel economy and satisfy needs for environment protection, idling stop control has been widely introduced. The idling stop control refers to a control for automatically stopping an idling engine when a vehicle comes to a stop, for example, at traffic lights. In a typical engine that performs idling stop control, a compressor that is selectively driven by a vehicle engine and an electric motor portion is used so that the compressor resumes air conditioning even if the engine is not running.  
           [0003]    If the power of the electric motor portion in such a compressor is designed to match the power of a vehicle engine, the size of the motor will be increased. However, if the size of the electric motor portion is excessively increased, the motor portion cannot be installed in an engine compartment. Therefore, a relatively compact electric motor portion is used for this type of compressor.  
           [0004]    To permit a compressor to be driven by a small power compact electric motor portion, the load on the motor portion needs to be reduced. Japanese Laid-Open Patent Publication No. 2001-80348 discloses this type of air conditioning system which is selectively driven by a vehicle engine and an electric motor. This air conditioning system has an evaporator, which is located in an air passage and forms a part of a refrigerant circuit. The evaporator cools air sent from a blower. An intake door located at the inlet of the air passage is switched between an outside air conducting position for conducting air from the exterior of the vehicle into the air passage, and an internal air circulation position for conducting air from the cabin into the air passage. An air mix door is located in a downstream section of the air passage. The opening size of the air mix door is changed for adjusting the flow rate of air sent to a heater core through the evaporator. Accordingly, the temperature of air sent from the air passage to the cabin is controlled.  
           [0005]    In this air conditioning system, air in the cabin is introduced into the air passage by switching the intake door. The air mix door is shut for preventing the air from reaching the heater core at a full cooling position. Thus, air in the cabin, the temperature of which is controlled, is drawn into the air passage and then cooled by the evaporator. The cooled air is released to the cabin without flowing through the heater core.  
           [0006]    Since the air in the cabin is drawn into the air passage, power consumption of the compressor is reduced compared to the case where the intake door is switched to the position for conducting air from the exterior. The temperature of the cabin is controlled. Further, the temperature of air blown out of the system is cooled by the evaporator when the air mix door is at the fully cooling position. The power consumption of the compressor is reduced, accordingly, compared to the state where the air mix door is open to pass the air through the heater core. Therefore, although the small power electric motor portion is used, cooling performance of the system is guaranteed to a certain extent.  
           [0007]    However, in the above air conditioning system, the positions of the intake door and the air mix door are changed after the engine is stopped. The positions of the intake door and the air mix door are changed when the intake door is at the position for introducing the air from the exterior of the vehicle and the air mix door is at a position for conducting the air to the heater core. Since the positions of the doors are changed in a relatively quiet state, or when the engine is not running, the noise of the door movements disturbs the passengers.  
           [0008]    When the engine E is stopped while the air mix door is open and the intake door is at the position for conducting outside air, the doors are moved after a certain period has elapsed. During this period, some air is introduced from the exterior of the vehicle and passes through the heater core, which increases the temperature of air sent to the cabin. The increase of the air temperature also disturbs the passengers.  
         BRIEF SUMMARY OF THE INVENTION  
         [0009]    Accordingly, it is an objective of the present invention to provide a vehicle air conditioner that guarantees an adequate cooling performance when a compressor is driven by a compact motor portion and also guarantees passenger comfort.  
           [0010]    It is another objective of the invention to provide an air conditioning system having a compressor and an evaporator. The compressor is driven by a vehicle engine and a motor separately operable from the vehicle engine. The evaporator is disposed in a predetermined air passage to cool the air. The air conditioning system comprises an intake door, predicting means, and switching means. The intake door is disposed upstream of the air passage and is switched between a first position and a second position. The intake door is arranged to introduce ambient air from outside of the vehicle in the first position and interior air from inside the vehicle in the second position. The predicting means is disposed for predicting a non-operating state of the vehicle engine. The switching means is disposed for switching the intake door to the second position based on a prediction of the predicting means.  
           [0011]    Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:  
         [0013]    [0013]FIG. 1 is a cross-sectional view illustrating a variable displacement swash plate type compressor;  
         [0014]    [0014]FIG. 2 is a schematic diagram showing a vehicle air conditioner; and  
         [0015]    [0015]FIG. 3 is a flowchart showing air conditioning control executed by an air conditioner ECU. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]    A preferred embodiment of the present invention will now be described.  
         [0017]    As shown in FIG. 1, a variable displacement swash plate type compressor C includes a housing  11 . A crank chamber  12  is defined in the housing  11 . A drive shaft  13  is rotatably provided in the crank chamber  12 . The drive shaft  13  is coupled to an output shaft of a vehicle engine E through a power transmission PT.  
         [0018]    The power transmission PT includes a rotor  80 , which is rotatably supported by the housing  11 . The rotor  80  is engaged with a belt  81 , which is also engaged with the engine E. A hub  82  is fixed to a portion of the drive shaft  13  that protrudes out of the housing  11 . A conventional one-way clutch  83  is located between the rotor  80  and the hub  82 .  
         [0019]    The power transmission PT includes an electric motor  84 . The electric motor  84  is located radially inward of the rotor  80 . The motor  84  includes a stator  84   a  and a rotor  84   b . The stator  84   a  is fixed to the housing  11 . The rotor  84   b  is fixed to the hub  82  and surrounds the stator  84   a . Supplying current to the stator  84   a  generates rotational force at the rotor  84   b  and rotates the drive shaft  13  through the hub  82 . In this state, the one-way clutch  83  blocks transmission of power from the hub  82  to the rotor  80 . The rotational force generated by the motor  84  is therefore not undesirably transmitted to the engine E.  
         [0020]    The one-way clutch  83  permits power to be transmitted from the rotor  80  to the hub  82 . Therefore, when the engine E is running, power of the engine E is transmitted to the drive shaft  13  through the rotor  80  and the hub  82 .  
         [0021]    A lug plate  14  is coupled to the drive shaft  13  and is located in the crank chamber  12 . The lug plate  14  rotates integrally with the drive shaft  13 . A swash plate  15  is accommodated in the crank chamber  12 . The swash plate  15  slides along and inclines with respect to the drive shaft  13 .  
         [0022]    A hinge mechanism  16  is arranged between the lug plate  14  and the swash plate  15 . The hinge mechanism  16  permits the swash plate  15  to rotate integrally with the lug plate  14  and the drive shaft  13 , and to incline with respect to the drive shaft  13 .  
         [0023]    The housing  11  has cylinder bores  11   a  (only one is shown). Each cylinder bore  11   a  accommodates a single-headed piston  17 . Each piston  17  reciprocates inside the corresponding cylinder bore  11   a . Each piston  17  is coupled to the peripheral portion of the swash plate  15  by a pair of shoes  18 . The shoes  18  convert rotation of the swash plate  15 , which rotates with the drive shaft  13 , to reciprocation of the pistons  17 .  
         [0024]    A compression chamber  20  is defined at the rear section (right section as viewed in FIG. 1) of each cylinder bore  11   a . The compression chamber  20  is defined by the corresponding piston  17  and a valve plate assembly  19  provided in the housing  11 . A suction chamber  21  and a discharge chamber  22  are defined in the rear section of the housing  11 .  
         [0025]    The valve plate assembly  19  has suction ports  23 , suction valve flaps  24 , discharge ports  25  and discharge valve flaps  26 . Each set of the suction port  23 , the suction valve flap  24 , the discharge port  25  and the discharge valve flap  26  corresponds to one of the cylinder bores  11   a . As each piston  17  moves from the top dead center to the bottom dead center, refrigerant gas in the suction chamber  21  is drawn into the corresponding compression chamber  20  through the corresponding suction port  23  while flexing the suction valve flap  24  to an open position. Refrigerant gas that is drawn into the compression chamber  20  is compressed to a predetermined pressure as the piston  17  is moved from the bottom dead center to the top dead center. Then, the gas is discharged to the discharge chamber  22  through the corresponding discharge port  25  while flexing the discharge valve flap  26  to an open position.  
         [0026]    As shown in FIG. 1, a bleed passage  27  and a supply passage  28  are formed in the housing  11 . The bleed passage  27  connects the crank chamber  12  with the suction chamber  21 . The supply passage  28  connects the crank chamber  12  with the discharge chamber  22 . A control valve  29  is located in the housing  11  to regulate the supply passage  28 . The control valve  29  is an electromagnetic valve that includes a valve body  29   a  and an electromagnetic actuator  29   b . The valve body  29   a  is actuated by the electromagnetic actuator  29   b  to regulate the opening size of the supply passage  28 .  
         [0027]    The opening of the control valve  29  is adjusted to control the balance between the flow rate of highly pressurized gas supplied to the crank chamber  12  through the supply passage  28  and the flow rate of gas conducted out from the crank chamber  12  through the bleed passage  27 . The pressure in the crank chamber  12  is thus adjusted. As the pressure in the crank chamber  12  varies, the difference between the pressure in the crank chamber  12  and the pressure in the compression chambers  20  with the pistons  17  in between is changed. This changes the inclination angle of the swash plate  15 . Accordingly, the stroke of each piston  17 , or the compressor displacement, is controlled.  
         [0028]    For example, when the pressure in the crank chamber  12  is decreased, the inclination angle of the swash plate  15  is increased. The displacement of the compressor C is increased, accordingly. When the pressure in the crank chamber  12  is increased, the inclination angle of the swash plate  15  is decreased. The displacement of the compressor C is decreased, accordingly.  
         [0029]    As shown in FIG. 1, the refrigerant circuit of the vehicle air conditioner, or the cooling cycle, includes the compressor C and an external refrigerant circuit  30 . The external refrigerant circuit  30  includes a condenser  31 , an expansion valve  32 , and an evaporator  33 .  
         [0030]    As shown in FIG. 2, an outside air inlet  41   a  and an in-car air inlet  41   b  are formed in the most upstream section of an air conditioner duct  41 . The outside air inlet  41   a  opens to the outside of the cabin. The in-car air inlet  41   b  opens to the cabin. An intake door  42  is located in the air conditioner duct  41 . The intake door  42  selectively opens and closes the outside air inlet  41   a  and the in-car air inlet  41   b . The intake door  42  includes an intake door actuator  43 , which is, for example, a servomotor. The intake door  42  is opened and closed by the intake door actuator  43 .  
         [0031]    For example, during heating or during normal cooling, the intake door  42  is switched to the position of the outside air inlet  41   a  as shown by two dotted chain line in FIG. 2. In this position, outside air is introduced. In other words, the intake door  42  is at an “outside air conducting mode”. On the other hand, during rapid cooling, the intake door  42  selects the in-car air inlet  41   b  as shown by a solid line in FIG. 2 to draw the air from the cabin. In other words, the intake door  42  is switched at an “internal circulation mode.” 
         [0032]    A blower  44  is located downstream of the intake door  42  and in a section of the air conditioner duct  41 . An evaporator  33  of the refrigerant circuit is located downstream of the blower  44  in the refrigerant circuit. The evaporator  33  cools air from the blower  44 .  
         [0033]    A heater core (heater)  45  is located in the air conditioner duct  41  downstream of the evaporator  33 . The heater core  45  uses, for example, coolant of the engine E as the heat source. An air mix door  46  is located upstream of the heater core  45 . The air mix door  46  splits air cooled by the evaporator  33  into a flow through heater core  45  and a flow that detours around the heater core  45 . The air mix door  46  is opened and closed by an air mix door actuator  47 , which is, for example, a servomotor.  
         [0034]    Air cooled and dehumidified by the evaporator  33  is split by the air mix door  46 . In accordance with the opening degree of the air mix door  46 , the flow rate of the air sent to the heater core  45  and the flow rate of the air that detours around the heater core  45  are determined. The air that flows through the heater core  45  is heated. The split air is mixed at a section downstream of the heater core  45 . Accordingly, the temperature of the air is adjusted to a desired temperature. The air of the adjusted temperature is blown into the cabin through an outlet  41   c  located downstream of the air conditioner duct  41 .  
         [0035]    If the air mix door  46  is at a fully heating position (fully open), as shown by two-dot chain line in FIG. 2, most of air that passed through the evaporator  33  flows through the heater core  45 , which improves the heating performance. If the air mix door  46  is at a fully cooling position (fully closed), as shown by solid line in FIG. 2, most of air passed through the evaporator  33  detours around the heater core  45 , which improves the cooling performance.  
         [0036]    As shown in FIG. 2, the vehicle has an air conditioner ECU  51  and an engine ECU  52 . The air conditioner ECU  51  controls air conditioning. The engine ECU  52  controls the engine E, or controls the start, stop, and output of the engine E. The ECUs  51 ,  52  are electronic control units or controllers similar to computers. The air conditioner ECU  51  serves as predicting means for predicting a non-operating state of the vehicle engine, switching means for switching the intake door, and controlling means for controlling the position of the air mix door. The air conditioner ECU  51  and the engine ECU  52  are connected to each other to communicate with each other.  
         [0037]    The engine ECU  52  is connected to a vehicle speed sensor  55  and an engine speed sensor  56 . The vehicle speed sensor  55  detects the speed V of the vehicle. The engine speed sensor  56  detects the speed Ne of the engine E. The engine ECU  52  performs idling stop control. In the idling stop control, the engine ECU  52  stops the idling engine E when, for example, the vehicle stops at traffic lights without manipulation of the ignition switch (not shown) by the driver. Automatic stop of the engine E is executed when the vehicle speed information V from the vehicle speed sensor  55  is zero and the engine speed information Ne from the engine speed sensor  56  represents a state of idling for a predetermined period.  
         [0038]    The air conditioner ECU  51  is connected to an air conditioner switch  58 , a temperature setter  59 , an in-car temperature sensor  60 , and an evaporator temperature sensor  61 . The air conditioner switch  58  is used for turning on and off the air conditioner. The temperature setter  59  is used for setting a target temperature in the cabin. The in-car temperature sensor  60  detects the temperature in the cabin. The evaporator temperature sensor  61  detects the temperature of air just passed through the evaporator (after evaporator temperature). The air conditioner ECU  51  controls the motor  84  of the power transmission PT, the control valve  29  of the compressor C, the blower  44 , the intake door  42 , and the air mix door  46  based on information from the information detection means  58 - 61 , and the information from the information detection means  55 ,  56  sent through the engine ECU  52 .  
         [0039]    The air conditioner ECU  51  controls the electromagnetic actuator  29   b  of the control valve  29 , the blower  44 , the intake door actuator  43 , and the air mix door actuator  47  based on target temperature information from the temperature setter  59 , the in-car temperature information from the in-car temperature sensor  60 , and the evaporator temperature information from the evaporator temperature sensor  61 , thereby controlling air conditioning elements, such as the target temperature information, the in-car temperature information, the after evaporator temperature information, in a normal manner such that air having a desirable temperature is blown into the cabin. In other words, the above described temperature setter  59 , in-car temperature sensor  60  and evaporator temperature sensor  61  serve as instruction means which provide information regarding thermal load of the air conditioner to the controller.  
         [0040]    When the air conditioner switch  58  is on, the air conditioner ECU  51  performs the air conditioning control in accordance with the flowchart of FIG. 3.  
         [0041]    That is, in step (hereinafter referred to as S)  101 , the air conditioner ECU  51  starts a normal control. In S 102 , the air conditioner ECU  51  predicts stopping of the vehicle based on the vehicle speed information V sent from the engine ECU  52 . Specifically, when the vehicle speed information V from the engine ECU  52  falls below a predetermined value (set 1 , which is for example 10 km per hour), the air conditioner ECU  51  determines that the driver is trying to stop the vehicle. In this case, the air conditioner ECU  51  predicts that the idling stop control (stopping of the engine E) will soon be executed. If the outcome of S 102  is negative, the monitoring of stopping of the vehicle is continued.  
         [0042]    If the outcome of S 102  is positive, the air conditioner ECU  51  proceeds to S 103 . In S 103 , the air conditioner ECU  51  judges whether the thermal load is high based on the target temperature information from the temperature setter  59 , the in-car temperature information from the in-car temperature sensor  60 , and the evaporator temperature information from the evaporator temperature sensor  61 . If the outcome of S 103  is negative, the air conditioner ECU  51  continues the normal control and proceeds to S 105 .  
         [0043]    If the outcome of S 103  is positive, the air conditioner ECU  51  proceeds to S 104  and restricts some processes in the normal control. That is, in S 104 , the intake door  42  is fixed to a position for drawing the air from the cabin, and the air mix door  46  is fixed to a position to blocking air flow to the heat core  45 . If the intake door  42  is at a position to draw outside air immediately before S 104  is executed, the position of the intake door  42  is gradually changed taking a predetermined period in S 104 .  
         [0044]    If the outcome of S 103  is negative or when S 104  is finished, the air conditioner ECU  51  proceeds to S 105 . In S 105 , the air conditioner ECU  51  judges whether the vehicle speed V is less than a predetermined value V (set 2 , which is, for example, 30 km per hour). If the outcome of S 105  is negative, that is, if the vehicle speed has greatly accelerated since the execution of S 102 , the air conditioner ECU  51  judges that the prediction that the vehicle is stopping proves wrong and returns to step  101 . Therefore, if S 104  has been executed, the restriction to the normal control in S 104  is discontinued, and the normal air conditioning is executed without restriction.  
         [0045]    If the outcome of S 105  is positive, the air conditioner ECU  51  proceeds to S 106  and determines whether the engine E has been stopped based on the engine speed information from the engine ECU  52 . That is, if the engine speed information Ne from the engine ECU  52  is zero, the air conditioner ECU  51  determines that the engine E has stopped. Here, the air conditioner ECU  51 , which is a controller of the air conditioner, serves as a determining means to determine that the engine is stopped. If the outcome of S 106  is negative, the air conditioner ECU  51  proceeds to S 105  and monitors the vehicle speed V, or continues monitoring if the positive outcome of S 102  (prediction that vehicle is stopping) is right. If the outcome of S 106  is positive, that is, if the engine E is stopped according to the positive outcome of S 102 , the air conditioner ECU  51  proceeds to S 107 . In S 107 , the air conditioner ECU  51  serves as an actuator to drive the motor  84  of the power transmission PT so that the motor  84  drives the compressor C.  
         [0046]    When the compressor C is driven by the motor  84  after the routine of FIG. 3 except S 104  has been executed, which is low thermal load state, air conditioning through the above described normal control is performed. Therefore, like the case where the compressor C is driven by the engine E, comfortable air conditioning is performed. If S 104  has been executed, which is high thermal load state, part of the normal control is restricted. That is, the air intake mode is fixed to the internal circulation mode, and the air mix door  46  is fixed to the fully cooling position. Therefore, compared to a case where the air intake mode is fixed to the outside air intake mode or to a case where the air mix door  46  is open, the power consumption of the compressor C for blowing cooled air having the same temperature is reduced. Thus, the motor  84 , which produces less power than the engine E, guarantees a cooling performance of a certain degree.  
         [0047]    As described above, when the compressor C is driven by the motor  84 , the air conditioner ECU  51  fixes the intake door  42  at the internal circulation mode position and fixes the air mix door  46  at the fully cooling position. Thus, the motor  84 , which produces relatively small power, guarantees a cooling performance of a certain degree. When the compressor C is driven by the engine E, the air conditioner ECU  51  monitors whether the engine E is likely to stop. When predicting that the engine E will stop, the air conditioner ECU  51  fixes the intake door  42  at an internal air circulation position and the air mix door  46  at a fully cooling position. The air is not passed through the heat core  45  at the fully cooling position.  
         [0048]    That is, when the compressor C is driven by the motor  84 , the intake door  42  is at the outside air conducting position and the air mix door  46  is open, the positions of the intake door  42  and the air mix door  46  are changed in S 104  before the engine E is stopped. Therefore, the noise generated by changing the positions of the doors  42 ,  46  is inconspicuous in the noise of the engine E. Therefore, noise of the doors  42 ,  46  (the noise of the actuators  43 ,  47 ) does not disturb the passengers.  
         [0049]    The positions of the doors  42 ,  46  are changed before the engine E is stopped. Therefore, the temperature of air blown into the cabin is prevented from increasing in a short period, and the passengers are not disturbed, compared to the case where the doors are changed after the engine E is stopped.  
         [0050]    Generally, switching the intake air mode produces a great fluctuation of noise at the outlet  41   c . However, if the intake door  42  is at the position to introduce outside air immediately before S 104  of FIG. 3, the air conditioner ECU  51  switches the intake door  42  gradually to a position to introduce the air in the cabin in S 104 . Therefore, fluctuation of noise at the outlet  41   c  is prevented, which reduces disturbing noise when the engine E is stopped.  
         [0051]    In S 102  of FIG. 3, the air conditioner ECU  51  predicts whether the vehicle is stopping. When predicting that the vehicle is stopping, the air conditioner ECU  51  predicts that the engine E will stop. That is, the restriction of part of the normal control in S 104  is executed while the vehicle is running. Therefore, the noise of the doors  42 ,  46  is inconspicuous in the noise of the vehicle other than the noise of the engine E, or in the noise from the road. Therefore, the noise of the doors  42 ,  46  is effectively prevented from disturbing the passengers.  
         [0052]    The motor  84  is located in the power transmission PT. Compared to a case where an electric motor is located outside of the power transmission PT, the size of the motor  84  is limited. If the size is limited, the performance of the motor  84  is difficult to improve. The present invention is therefore advantageous in that the motor  84 , which produces relatively small power, guarantees a cooling performance to a certain degree.  
         [0053]    It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the invention may be embodied in the following forms.  
         [0054]    A brake sensor may be provided for detecting whether the brake pedal is depressed, or whether the vehicle is being braked. In this case, S 102  of FIG. 3 may be replaced by a step for determining that the driver is stopping the vehicle when the vehicle speed V is less than a predetermined value (for example, 30 km) and the brake pedal is being depressed.  
         [0055]    S 102  of FIG. 3 may be replaced by a step for determining that the driver is stopping the vehicle when the engine speed Ne drops from a value equal to or greater than a predetermined value, which is greater than the idling speed, to a value less than the predetermined value.  
         [0056]    S 103  of FIG. 3 may be omitted so that, when the motor  84  is driving the compressor, the intake door  42  is at the position to draw the air in the cabin regardless of the thermal load, and the air mix door  46  is fixed to the fully cooling position.  
         [0057]    S 104  of FIG. 3 may be changed such that only one of the intake door  42  and the air mix door  46  is changed.  
         [0058]    The air conditioner ECU  51  may have its own vehicle speed sensor and engine speed sensor. In this case, the air conditioner ECU  51  obtains the vehicle speed information V and the engine speed information Ne without transmission delay, which improves the accuracy of the air conditioning control.  
         [0059]    The present invention may be applied to a vehicle air conditioner using a power transmission PT that has no an electric motor. That is, the motor  84  may be located in the housing  11  of the compressor C. Alternatively, the motor  84  may be independent from the compressor C.  
         [0060]    The compressor C is not limited to a variable displacement type, but may be a fixed displacement type. In this case, a clutch mechanism such as an electromagnetic clutch is located in a power transmission path between the engine E and the compressor C to stop the compressor C when no cooling is needed while the engine E is running. The displacement of the compressor C is externally controlled through the electromagnetic valve  29  in the illustrated embodiment. The displacement of the compressor C is preferably minimized when no cooling is needed.  
         [0061]    The compressor C may be replaced by a wave cam plate type compressor or a doubled-headed piston type compressor. Alternatively, the compressor C may be replaced by non-piston type compressors such as a scroll compressor or a vane compressor. In other words, the present invention may be applied to a vehicle air conditioner equipped with any of the listed compressor.  
         [0062]    It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the invention may be embodied in the following forms.