Abstract:
A device for air conditioning of a motor vehicle interior, with a refrigerant circuit which has a compressor ( 21 ), a condenser ( 22 ) and at least one evaporator ( 30 ), with a heat exchange medium circuit which has at least one heat source (engine  10 , auxiliary vehicle heater  14 ) and at least one heat exchanger ( 12, 17 ). To simplify the system and to accelerate the response behavior when heating and cooling, it is provided that there an evaporator ( 30 ) of the refrigerant circuit and a heat exchanger ( 17 ) of the heat exchange medium circuit are both located in a reservoir ( 33 ) which is suited for selective storage of both heat and cold.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a device for air conditioning of a motor vehicle interior with a refrigerant circuit which comprises a compressor, a condenser, at least one evaporator, a heat exchange medium circuit which has at least one heat source and at least one heat exchanger, and at least one reservoir for storage of heat energy or cold energy.  
           [0003]    2. Description of Related Art  
           [0004]    An air conditioning device with a first refrigerant circuit which comprises a compressor, condenser and evaporator for cooling the vehicle interior, and a second refrigerant circuit which comprises another evaporator which is connected to the refrigerant reservoir and can be connected parallel to the first refrigerant circuit, is known from published German Patent Application DE 196 45 178 A1. To enable simple and comfortable auxiliary air conditioning, it is provided in the known device that a module comprised of an ice reservoir and a flat, second heat exchanger is located in one wall of the vehicle interior and can be directly connected by heat-transfer to the air of the vehicle interior. This known air conditioning device has proven itself in practice.  
           [0005]    Another device for air conditioning of a vehicle interior with a first heat exchange medium circuit which has the engine of the motor vehicle, the radiator of the engine, an auxiliary vehicle heater independent of the engine, a heat reservoir and at least one heat exchanger for heating the vehicle interior, and with another heat exchanger which is connected to the cooling circuit and the refrigerant reservoir, is known from published German Patent Application DE 196 25 927 A1. This known device has proven itself in practice and represents a development in comparison to the initially mentioned known device, since it stores both heat energy and cold energy. Both reservoir measures contribute to saving energy; on the other hand, the high weight and the space requirement of the two reservoir units is a disadvantage in motor vehicles.  
         SUMMARY OF THE INVENTION  
         [0006]    In view of this prior art, a primary object of the present invention is to devise a simplified air conditioning device for a motor vehicle interior.  
           [0007]    This object is achieved by the features described in greater detail below.  
           [0008]    The invention combines the cold reservoir principle and the heat reservoir principle in an economical and energy-saving manner while increasing the reaction speed of the air conditioning process. The core of the invention is accordingly formed by the integration of the refrigerant reservoir and the heat exchange medium reservoir in a single reservoir which contains a common heat exchange heat/cold reservoir medium. The management of this reservoir takes place by a control means which controls the loading and unloading of the reservoir depending on the cooling requirement or heating requirement in the heat exchange medium circuit.  
           [0009]    A cold refrigerant from the integral heat reservoir/cold reservoir is added to the heat exchange medium circuit to the required extent, preferably controlled by valves when there is a demand for cold in the vehicle interior, and vice versa, heat is purposefully supplied to the heat exchange medium circuit by the integral heat reservoir/refrigerant reservoir, when there is a corresponding demand for heat.  
           [0010]    Advantageously, for environmental and cost reasons, the common reservoir medium is water which is often provided with antifreeze.  
           [0011]    To eliminate the need for assemblies such as circulation pumps, as compared to the known separately executed air conditioning device based on cold reservoirs or heat reservoirs, they can be used jointly in the device in accordance with the invention so that the number is reduced.  
           [0012]    The invention is detail below with reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The sole FIGURE is a block diagram schematically showing one embodiment of the air conditioning device in accordance with the invention for the vehicle interior. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]    The heat exchange medium circuit comprises the motor vehicle engine  10 , the radiator  11  for cooling the vehicle engine  10 , a heat exchanger  12  with an assigned fan for delivering heated air into the vehicle interior  37  which is indicated schematically by dot-dash lines, and an auxiliary vehicle heater  14 . In the feed line  38  from the auxiliary vehicle heater  14  to the heat exchanger  12  and in the discharge line  39  from the heat exchanger  12  to the motor vehicle engine  10  there are temperature sensors  15 ,  16 , respectively.  
         [0015]    The second part of the heat exchange medium circuit comprises another heat exchanger  17  which can be connected in parallel to the heat exchanger  12  and for this purpose can be connected using a flow line  40  and a return line  41  to the lines  38 ,  39  to/from the heat exchanger  12 . In the flow line  40  to the other heat exchanger  17 , there is a circulation pump  18 . The flow line  40  to the other heat exchanger  17  contains a first solenoid valve  19  and the return line  41  contains a second solenoid valve  20  which is preferably designed as a three-way valve in the connection area to the feed line  38 .  
         [0016]    The first refrigerant circuit comprises a compressor  21 , a condenser  22  to which two fans  23 ,  24  are assigned, and an evaporator  25  to which one fan  26  is assigned with which air is conveyed through the evaporator  25  and delivered into the vehicle interior  37  as cold air. In the connecting line of the evaporator  25  to the condenser  22  there is a solenoid valve  27 , and furthermore, a viewing window  35  and a collector/drier  36 . Another solenoid valve  28  is series connected to the solenoid valve  27  and controls a bypass line  29  of the evaporator  25 .  
         [0017]    The second part of the refrigerant circuit comprises another evaporator  30  which can be connected parallel to the evaporator  25 . In the connecting line from the evaporator  30  to the refrigerant circuit there are an expansion valve  31  and a solenoid valve  32 . The expansion valve  31  can also be located elsewhere in the refrigerant circuit.  
         [0018]    The other evaporator  30  and the other heat exchanger  17  are located in a common heat reservoir/cold reservoir  33  or are combined into it, and it contains a common heat reservoir/cold reservoir medium  34  for example, in the form of water into which heat can be delivered by means of the heat exchanger  17  and cold can be delivered by means of the evaporator  25 .  
         [0019]    The part of the refrigerant circuit comprising the evaporator  25  is only an option. Under certain circumstances, it is sufficient to meet the demand for cold in the motor vehicle interior  37  via the heat exchanger  12  which absorbs cold energy by indirect heat exchange of the heat exchanger  17  with the evaporator  30 .  
         [0020]    Certain modes of operation of the air conditioning device in accordance with the invention for the vehicle interior are explained below.  
         [0021]    First of all, it is assumed that the refrigerant circuit with the first evaporator  25  and the second evaporator  30  are not active.  
         [0022]    When the vehicle is in operation, the motor vehicle engine  10  heats up. When there is a heat demand in the vehicle interior  37  and when a minimum temperature is reached in the heat exchange medium circuit, coolant flows which travels through the motor vehicle engine  10  to the heat exchanger  12 . The fan  13  conveys air through the heat exchanger  12  in order to deliver it to the vehicle interior  37 . The coolant flows from the motor vehicle engine  10  via the three-way solenoid valve  20  and the feed line  38  into the heat exchanger  12 . After leaving the heat exchanger  12 , the coolant flows via the discharge line  39  back to the motor vehicle engine  10 . In this case or operating mode, it is assumed that the auxiliary vehicle heater  14  is not active since the vehicle is being driven.  
         [0023]    In the case in which the motor vehicle is stopped or the heat demand cannot be met by the motor vehicle engine  10 , alternatively or additionally, the auxiliary motor vehicle heater  14  is active and feeds heat into the coolant in the heat exchange medium circuit, in order, on the one hand, to heat the engine  10 , and on the other to supply heat energy to the heat exchanger  12 , so that the vehicle interior  37  can be heated via the fan  13 . In the just explained operation with or without the auxiliary vehicle heater  14 , the part of the heat exchange medium circuit which encompasses the other heat exchanger  17  is not operatively connected to the first heat exchange medium circuit. This is achieved by the solenoid valve  19  being set into a closed state and the circulation pump  18  not being actuated.  
         [0024]    Starting at the time at which the heat exchange circuit produces excess heat, i.e., more heat than is to be delivered, for example, by the heat exchanger  12  into the vehicle interior  37 , the second part of the heat exchange medium circuit is connected in parallel to the heat exchange medium circuit, i.e., the solenoid valve  19  is opened some and the circulation pump  18  is actuated so that the excess heat energy can travel into the other heat exchanger  17  and is stored there in the reservoir medium  34  of the integral heat reservoir/cold reservoir  33 .  
         [0025]    An operating mode is assumed below in which the motor vehicle air conditioning system is active, the second evaporator  30  not being operatively connected to the first evaporator  25 . The motor vehicle air conditioning system produces cold which is transported by means of the refrigerant according to the requirements in the motor vehicle interior  37  to the evaporator  25 . The air cooled by the evaporator  25  is delivered to the vehicle interior  37 . In this case, proceeding from the uncharged heat reservoir/cold reservoir  33 , first the second evaporator  30  is not connected to the first evaporator  25  as long as all the cold energy is needed for cooling the vehicle interior  37 . As soon as this supply demand in the vehicle interior  37  is met and excess cold energy is produced by the air conditioning system, the second evaporator  30  is operatively connected in parallel to the first evaporator  25 , i.e., the solenoid valve  32  is opened some so that the excess cold energy passes through the other evaporator  30  and is stored in the reservoir medium  34 .  
         [0026]    With the cold or heat stored in the reservoir  33 , it is possible to proceed in different ways.  
         [0027]    For example, in the case in which there is an increased cold demand in the vehicle interior  37  and the reservoir  33  contains stored cold, the second part of the heat exchange medium circuit is briefly connected to the heat exchanger  17 , and in this case, the cold stored in the reservoir  33  being added to the heat exchange medium circuit by the heat exchanger  17  and supplied to the heat exchanger  12 .  
         [0028]    In the reverse case, in a similar manner with a strong demand for heat in the vehicle interior  37  and with heat energy stored in the reservoir  33 , heat energy can be taken from the reservoir  33  by parallel connection of the second part of the heat exchange medium circuit with the heat exchanger  17  to the heat exchange medium circuit from the reservoir  33  in order to add it to the heat exchange medium and deliver it to the heat exchanger  12 .  
         [0029]    Summary of the possible operating modes:  
         [0030]    A. Cooling of the vehicle interior from the reservoir (auxiliary cooling)  
         [0031]    The reservoir medium  34  is cold due to prior operation of the compressor  21 . The solenoid valve  19  is opened and the solenoid valve  20  connects the flow line  40  to the feed line  38 . The circulation pump  18  circulates the heat exchange medium which has been cooled by the reservoir medium  34  through the heat exchangers  17  and  12 .  
         [0032]    B. Cooling of the vehicle interior by the motor vehicle air conditioning system via the reservoir  
         [0033]    As soon as the temperature on the temperature sensor  16  or a pressure valve on the evaporator  30  signals that the cooling capacity of the reservoir  33  is exhausted, the compressor  21  starts and charges the reservoir  33  via the evaporator  30  again. The compressor  21  can only be operated with simultaneous operation of the motor vehicle engine  10 . If, while driving, cooling is produced indirectly via the reservoir  33 , it acts as a larger buffer, by which continuous turning on and off of an uncontrolled compressor is prevented and the cycles are prolonged.  
         [0034]    C. Direct cooling via the air conditioning system  
         [0035]    With high cold demand in the vehicle interior  37 , the latter is exposed directly to refrigerant from the refrigerant circuit via the (optional) evaporator  25 . The evaporator  25  can also be located in the air flow horizontally in succession with the heat exchanger  12  so that instead of the two fans  13  and  26 , only a single fan is necessary.  
         [0036]    D. Double cooling  
         [0037]    With very high cold demand and with the reservoir  33  charged with cold energy, parallel operation of the two operating modes A and C can take place. Here, cold water is delivered via the heat exchanger  17  from the reservoir  33  into the heat exchanger  12  and in addition refrigerant is delivered to the evaporator  25 .  
         [0038]    E. Preheating from the reservoir  
         [0039]    When the reservoir medium  34  is warm from prior operation of the motor vehicle engine  10  and/or the auxiliary vehicle heater  14 , with the solenoid valves  19  and  20  opened, hot water can be delivered by the circulation pump  18  through both of the heat exchangers  17  and  12 .  
         [0040]    F. Preheating or heating by the auxiliary motor vehicle heater  
         [0041]    With the solenoid valve  19  closed, the heat exchange medium is delivered by a circulation pump integrated into the auxiliary motor vehicle heater  14  through the heat exchanger  12 .  
         [0042]    G. Preheating or heating by the auxiliary motor vehicle heater and reservoir or charging of the reservoir by the auxiliary motor vehicle heater  
         [0043]    With the reservoir  33  charged, the operating modes E and F can be combined for especially prompt preheating of the vehicle interior  37 . In doing so, the heat exchange medium flows through the auxiliary motor vehicle heater  14  which can also be located in the feed line  38  between the solenoid valve  20  and the heat exchanger  12 , through the heat exchanger  12  and the heat exchanger  17 . The solenoid valves  19  and  20  are opened accordingly and the circulation pump  18  is in operation. The same circuit connection can also be used for charging the reservoir  33  by means of the auxiliary motor vehicle heater  14  when the heat energy produced by the auxiliary motor vehicle heater  14  is greater than the energy removed by the heat exchanger  12 .  
         [0044]    H. Additional heating with the motor vehicle engine  
         [0045]    In the above described operating modes E, F, and G, the motor vehicle engine  10  can also be in operation. Thus, three heat sources, i.e., the motor vehicle engine  10 , the auxiliary motor vehicle heater  14 , and the reservoir  33  can be selectively or simultaneously interconnected in the heat exchange medium circuit. Depending on the heat state of the individual heat sources and after heat dissipation on the heat exchanger  12 , the motor vehicle engine  10  can be preheated by the auxiliary motor vehicle heater  14  and/or the reservoir  33  or can feed heat energy into the heat exchange medium circuit which is then used, for example, to charge the reservoir  33 .