JP2005081965A - Air conditioning system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioning system for a vehicle for performing a control so that blow off wind into the cabin has not extremely high temperature comparing with the outside temperature at an A/C ON time in a situation where the temperature in the cabin is relatively high with respect to the temperature outside the vehicle, even when a variable displacement compressor is used for compressing a refrigerant. <P>SOLUTION: In an air conditioning controller for the vehicle using a variable displacement compressor for compressing the refrigerant, the temperature outside the vehicle and the temperature in the cabin have a predetermined relation after starting the compressor, and outside air introducing mode is used while the compression degree by the compressor is a predetermined level or lower. The predetermined relation may be a relation in which the temperature outside the vehicle is a first predetermined temperature and the temperature in the cabin is lower than a second predetermined temperature, or may be a relation in which the difference between the temperature outside the vehicle and the temperature in the cabin is a predetermined value or higher. The compression degree may be determined based on the magnitude of refrigerant high pressure, or based on the level of the evaporator temperature. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention generally relates to a vehicle air conditioning system, and more particularly to a vehicle air conditioning system that uses a variable displacement compressor for refrigerant compression.

  As a system for realizing air conditioning (air conditioner) in a vehicle, a vehicle air conditioning system using a liquid refrigerant is well known.

  When liquid refrigerant is used, a compressor that compresses the refrigerant usually has a large heat capacity, and thus there may be a problem that the liquid refrigerant is stored in the compressor. Such storage of liquid refrigerant can occur, for example, when the outside air temperature of the vehicle is 15 to 20 ° C. (in some cases to 25 ° C.) and the temperature in the passenger compartment increases due to sunlight (sunlight) or the like. . In particular, when the temperature in the passenger compartment rises, the refrigerant present in the passenger compartment also moves to the compressor and is stored there.

  If liquid refrigerant is present in the compressor, it will be in a so-called liquid compression state until the stored liquid refrigerant is discharged (it may take up to about 60 seconds) when the compressor is started. The refrigerant is not compressed normally even though it is rotating. If the refrigerant is not compressed, the refrigerant does not turn to the evaporator, and no cold air is generated by the latent heat of the refrigerant, so that no cold air is supplied into the vehicle interior.

  In particular, when the air conditioner (A / C) is turned on, the vehicle interior temperature is high. Therefore, when the inside air circulation mode (recirculating; REC) and the maximum blown air volume are set by the control of the auto air conditioner or the user's selection, Will be exposed to hot air reaching 50-60 ° C. As described above, since this can occur when the outside air temperature is relatively cool, the vehicle occupant is particularly uncomfortable. Furthermore, since the cool air does not blow out even though the A / C is on the indicator, the vehicle occupant may be suspected that the A / C has failed.

  A technique for taking countermeasures by paying attention to the stored liquid refrigerant in the compressor that can cause such an effect has also been proposed (see, for example, Patent Document 1).

In the device described in Patent Document 1, when the starter motor is rotating by turning on an ignition switch (hereinafter referred to as “IG”), the magnet clutch is connected to rotate the compressor, and the engine is stored in the compressor during engine startup. The liquid refrigerant is to be discharged as much as possible.
JP-A-8-197938

  The conventional device described in Patent Document 1 is based on the premise that the liquid refrigerant stored in the compressor is discharged to some extent if the compressor rotates even slightly. That is, it is assumed that a so-called fixed displacement compressor is used as the air conditioning system compressor. As known to those skilled in the art, if the compressor has a fixed capacity, the stored liquid refrigerant can be forcibly discharged by its rotation.

  Today, however, variable displacement compressors aimed at dynamically changing the compression capacity have been used so that a cooling capacity greater than necessary (in other words, driving power taken from the engine) does not occur. Yes.

  In the variable displacement compressor, the refrigerant is not compressed unless pressure is applied. For example, in the case of an inclined plate piston type variable displacement compressor known to those skilled in the art, the inclined plate is inclined by a pressure difference. Therefore, if no pressure is applied, the inclined plate remains at 0 °, and compression is performed. Not done. That is, even if the compressor is slowly rotated for a very short time (or several revolutions) by the rotation of the starter motor, the liquid refrigerant stored in the variable capacity compressor is not discharged.

  As described above, the conventional apparatus (and its control method) has a problem that it cannot be applied to a variable displacement compressor as it is.

  The present invention is for solving such problems. Even when a variable displacement compressor is used for compressing the refrigerant, the A / C ON is performed in a situation where the vehicle interior temperature is relatively high with respect to the vehicle outside temperature. The main object of the present invention is to provide a vehicle air-conditioning system that is controlled so that the air blown into the passenger compartment sometimes does not become significantly hotter than the outside air temperature.

  One aspect of the present invention for achieving the above object is a vehicle air-conditioning control apparatus that uses a variable displacement compressor for refrigerant compression, and after starting the compressor, the vehicle outside temperature and the vehicle interior temperature have a predetermined relationship. In addition, the vehicle air-conditioning control device is in the outside air introduction mode (fresh; FRS) while the degree of compression by the compressor is below a predetermined level.

  In this aspect, the predetermined relationship may be a relationship in which the vehicle outside temperature is less than the first predetermined temperature and the vehicle interior temperature is equal to or higher than the second predetermined temperature, or the vehicle interior temperature is The relationship may be higher than the vehicle outside temperature by a predetermined value or more.

  Further, in this aspect, the degree of compression may be determined by the magnitude of the refrigerant high pressure (the refrigerant pressure at any point on the refrigerant cycle until it is compressed by the compressor and becomes a low pressure gas by the evaporator) Or you may judge by the height (low) of evaporator temperature. When the refrigerant high pressure becomes larger than the predetermined value and / or when the evaporator temperature becomes lower than the predetermined value, it is determined that the refrigerant has started to be compressed, that is, the stored liquid refrigerant has been discharged from the compressor. can do.

  According to this aspect, the outside air introduction mode is set in a situation where it is expected that the refrigerant is not compressed because the liquid refrigerant is stored in the compressor from the relationship between the vehicle outside temperature and the vehicle interior temperature. Therefore, it is possible to avoid blowing air that is significantly hotter than the outside air temperature before the refrigerant starts to be compressed.

  In the auto A / C control, conventionally, in order to cool the passenger compartment air efficiently, it is usually performed positively in the inside air circulation mode. As in the present invention, it is dared to start the A / C under predetermined conditions. The outside air introduction mode is a new idea.

  The variable displacement compressor in this aspect may be any compressor that does not start compression unless pressure is applied. For example, a vane compressor in addition to the inclined plate piston compressor exemplified above. Examples thereof include an inclined plate opposed piston compressor, a scroll compressor, and the like.

  Further, in this aspect, “to enter the outside air introduction mode” means a) switching to the outside air introduction mode when the inside air circulation mode is set by the control of the auto air conditioner or the user's selection, and b) outside air introduction. It is intended to include both maintaining the outside air introduction mode even if the control of the auto air conditioner or switching to the inside air circulation mode is selected by the user under the mode.

  Further, in this aspect, as described above, the outside air introduction mode is set at the time of A / C start to avoid blowing air that is significantly higher than the outside air temperature into the passenger compartment before the refrigerant starts to be compressed. Therefore, for example, when it is determined that the refrigerant compression by the compressor is started from the refrigerant high pressure, for example, it is preferable to quickly switch to the inside air circulation mode and efficiently cool the vehicle interior.

  According to the present invention, even when a variable displacement compressor is used for compressing the refrigerant, the vehicle is operated in the inside air circulation mode when the A / C is turned on in a situation where the vehicle interior temperature is relatively high with respect to the vehicle outside temperature. It is possible to provide an air conditioning system for a vehicle that performs control so that the air blown into the room does not become remarkably higher than the outside air temperature.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. The vehicle air-conditioning system according to the present invention is predicated on a vehicle air-conditioning system (air conditioner) using a liquid refrigerant. However, those skilled in the art are aware of its own hardware configuration, operating principle, and basic control method. Since it is already known, detailed explanation is omitted.

  An embodiment of the present invention will be described with reference to FIGS. In this embodiment, when the passenger compartment temperature is higher than the outside air temperature, and the start-up at the start of A / C, which is predicted to be influenced by the stored liquid refrigerant in the compressor as described above, is delayed. Until the proper refrigerant compression by the compressor is started, the outside air introduction mode is set, and the temperature of the air blown into the passenger compartment is lowered as close as possible to the outside air temperature.

  FIG. 1 shows an outline of a vapor compression refrigerant cycle in a vehicle air conditioning system using a liquid refrigerant. Since the refrigerant circulates, there is no specific starting point, but for the sake of convenience, the explanation will be made very simply in order from the compressor (compressor).

  The low-pressure gaseous refrigerant is compressed by the compressor 101 (here, a variable capacity compressor that does not start compression unless pressure is applied), and becomes a high-temperature and high-pressure gas. This gas is sent to a condenser (condenser) 102, cooled by traveling air or a fan, and becomes liquid. The high-pressure liquid refrigerant is then expanded rapidly by an expansion valve (expansion valve) 103, atomized, and sent to an evaporator (vaporizer) 104. The atomized refrigerant is vaporized in the evaporator 104. During this vaporization, the refrigerant takes a large amount of heat from the surrounding fins and causes cooling. The vaporized refrigerant low-pressure gas is returned to the compressor 101 again.

  FIG. 2 illustrates parameters referred to by the air conditioning ECU 201 that controls the entire air conditioning system according to the present embodiment. As known to those skilled in the art, the air conditioning ECU 201 refers to various parameters in order to control the air conditioning system, but the parameters referred to for the inside / outside air switching control according to the present embodiment are as illustrated. Reference is made in particular to 1) high pressure refrigerant, 2) outside air temperature, 3) cabin temperature, and 4) current inside / outside air mode.

  Here, 1) the refrigerant high pressure is the pressure of the refrigerant when it is in a high temperature state in the refrigerant cycle (FIG. 1), and is compressed in the path from the compression by the compressor 101 to the low pressure in the expansion valve 103. The pressure at any point may be sufficient. For example, the refrigerant pressure immediately after the compressor 101 or the refrigerant pressure just before the expansion valve 103 may be used.

  2) The vehicle outside temperature is measured by, for example, an outside temperature sensor (not shown), and 3) The vehicle interior temperature is measured by, for example, a vehicle interior temperature sensor (not shown). Further, 4) the inside / outside air mode is an outside air introduction mode or an inside air circulation mode as is known.

  These parameters are parameters that the air conditioning ECU refers to in the case of a normal vehicle air conditioning system. Since these parameters have been referred to in the past, these parameters are acquired (detected) and transmitted in order to realize the present embodiment. There is no need to provide a separate hardware configuration. In this embodiment, since the compressor 101 is a variable displacement compressor as described above, in order to dynamically change the compression capacity, 1) the refrigerant high pressure is monitored, and the compression capacity currently being demonstrated is grasped. Yes.

  Next, the inside / outside air switching control at the time of A / C start according to the present embodiment by the air conditioning ECU 201 will be described using the flowchart of FIG. 3. This control is substantially started when the A / C is turned on after the IG is turned on and the compressor 101 starts operating (“YES” in S301). Here, A / C on is the same even if IG is turned on while A / C is on.

  First, in order to determine whether or not refrigerant compression by the compressor 101 has started, it is determined whether or not the refrigerant high pressure is less than a predetermined pressure value X (S302). The predetermined pressure value X can be arbitrarily set from various conditions such as compressor capacity.

  When the refrigerant high pressure is equal to or higher than the predetermined pressure value X (“NO” in S302), the liquid refrigerant is not stored in the compressor 101, and appropriate refrigerant compression is started almost simultaneously with the A / C start. It is determined that the cold air is blowing out, and normal inside / outside air switching control is performed regardless of the outside air temperature and / or the inside air temperature of the vehicle or their relationship (S306).

  Here, the normal inside / outside air switching control is performed according to the selection of the user or the judgment of the ECU if it is a so-called auto air conditioner without performing forced switching to the outside air introduction mode (S305; described later). This refers to switching control between the outside air introduction mode and the inside air circulation mode.

  When the refrigerant high pressure does not reach the predetermined pressure value X (“YES” in S302), it is next determined whether or not there is a relationship in which the vehicle interior temperature is significantly higher than the vehicle outside temperature. Specifically, it is determined whether or not the vehicle outside temperature is lower than the first predetermined temperature Y ° C. and the vehicle interior temperature is equal to or higher than the second predetermined temperature Z ° C. (S303 and S304, respectively).

  When the outside temperature of the vehicle is equal to or higher than Y ° C. (“NO” in S303) or the inside temperature of the vehicle is lower than Z ° C. (“NO” in S304), the inside of the vehicle is not hot enough to introduce outside air, or outside air is introduced. Therefore, the normal switching control is performed (S306).

  If the vehicle outside temperature is less than Y ° C. and the vehicle interior temperature is Z ° C. or more (“YES” in S303 and “YES” in S304), it is determined that the vehicle interior temperature is considerably higher than the vehicle outside air temperature. The air switching control is forcibly set to the outside air introduction mode regardless of the selection by the user or the automatic air conditioner control (S305).

  That is, if the user's selection or auto A / C control determination is the inside air circulation mode, the mode is switched to the outside air introduction mode, and if it is originally the outside air introduction mode, it is maintained, and switching to the inside air circulation mode is not permitted.

  When switched to the outside air introduction mode in this way, it is relatively cooler than the hot air blown into the vehicle interior (temperature close to the vehicle interior temperature) in the internal air circulation mode and under the situation where refrigerant compression in the compressor has not yet started. Since the blown air (close to the vehicle outside temperature) is blown into the passenger compartment, it is possible to reduce the discomfort of the vehicle occupant while the cold air is not emitted.

  After switching to the outside air introduction mode (S305), the process returns to S302, and the determinations of S302 to S304 are repeated. If even one of these three determinations is NO, the setting to the forced outside air introduction mode is canceled, and the normal control according to the user's selection or auto A / C control is returned (S306).

  Normally, when the stored liquid refrigerant is discharged from the compressor for a while after the A / C start, refrigerant compression by the compressor is started, the refrigerant high pressure becomes equal to or higher than the predetermined pressure value X (“NO” in S302), Return to normal control (S306). The time required for discharging the stored liquid refrigerant varies depending on the storage amount.

  As described above, according to this embodiment, in the vehicle air conditioning system using the variable capacity compressor, when the liquid refrigerant is stored in the compressor, the refrigerant starts to be compressed after the A / C is started. Thus, the temperature of the blown air blown into the passenger compartment can be reduced until the vehicle occupant feels uncomfortable.

  In particular, when the vehicle interior temperature is somewhat higher than the vehicle outside temperature, auto A / C control is almost certain, and as a general tendency even if set by the user, A / C start is performed to efficiently cool the vehicle interior. It is considered that the inside air circulation mode is selected for at least a while after. Under such circumstances, according to the present embodiment, hot air in the passenger compartment is prevented from circulating and cooler than the passenger compartment temperature even before the refrigerant is started to be compressed by the introduction of outside air. A blowing wind can be obtained.

  Further, according to the present embodiment, since outside air is also used to cool the passenger compartment air, an energy saving effect that energy consumption is suppressed is obtained, and a heat load on the air conditioning system is also reduced.

  As will be apparent to those skilled in the art, the present invention is not limited to the above-described embodiment, but can be implemented in various forms. For example, in the above-described embodiment, it may be determined whether or not compression by the compressor is started from the height (low) of the evaporator temperature instead of the refrigerant high pressure (if the temperature is lower than a predetermined temperature, the compression by the compressor is performed). ) Moreover, you may use the solar radiation amount (into a vehicle interior) measured with the solar radiation meter instead of vehicle interior temperature. Furthermore, the determinations in S303 and S304 may be combined into one to determine whether or not the difference between the vehicle interior temperature and the vehicle exterior temperature (vehicle interior temperature−vehicle exterior temperature) is equal to or greater than a predetermined value.

  In addition, as a modification of the above-described embodiment, for example, a) For example, after a predetermined time has elapsed after the forced introduction into the outside air introduction mode (S305), it may be automatically switched to the inside air circulation mode. Or, a) When switching from the forced outside air introduction mode (S305) to the normal air circulation mode (S306) under normal control, the outside air introduction mode is maintained until the elapsed time after entering the outside air introduction mode exceeds a predetermined time. It may be set to be maintained (that is, switched to the inside-air circulation mode after a predetermined time elapses), or c) a situation in which YES / NO frequently switches in any of the determinations of S302 to S304 In order to prevent the inside / outside air mode from switching too frequently, an upper limit may be set for the switching frequency, or d) changes in each parameter. It is possible to predict the possibility that the determination of any one of S302 to S304 will be switched to NO in the near future from the history, and to set the timing to return to the normal control based on the prediction, or e) A / It may be set so that the outside air introduction mode is forcibly set at the same time as C is turned on and the control is switched to the normal control when any of the determinations in S302 to S304 is NO.

  The present invention can be used in a vehicle air conditioning system. The appearance, weight, size, running performance, etc. of the vehicle are not limited.

It is a figure which shows the outline of the vapor compression type refrigerant cycle in the air-conditioning system using a liquid refrigerant. It is a figure which shows the parameter which air-conditioning ECU which concerns on one Example of this invention refers. It is a flowchart which shows the flow of the inside / outside air switching control at the time of the air-conditioner start-up concerning one Example of this invention.

Explanation of symbols

101 Compressor 102 Condenser 103 Expansion Valve 104 Evaporator 201 Air Conditioning ECU

Claims (5)

A vehicle air conditioning system that uses a variable displacement compressor to compress refrigerant,
The vehicle air conditioner is characterized in that after the compressor is started, the outside air temperature and the passenger compartment temperature are in a predetermined relationship, and the outside air introduction mode is set while the degree of compression by the compressor is below a predetermined level. system. The vehicle air conditioning system according to claim 1,
The predetermined relationship is a vehicle air conditioning system characterized in that the outside temperature of the vehicle is lower than a first predetermined temperature and the temperature inside the vehicle is equal to or higher than a second predetermined temperature. The vehicle air conditioning system according to claim 1,
The vehicle air-conditioning system is characterized in that the predetermined relationship is a relationship in which the vehicle interior temperature is higher than the vehicle outside temperature by a predetermined value or more. The vehicle air conditioning system according to any one of claims 1 to 3,
The degree of the compression is determined by the magnitude of the refrigerant high pressure. The vehicle air conditioning system according to any one of claims 1 to 3,
The degree of compression is determined by a high evaporator temperature.

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