JP5609803B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus in which a plurality of evaporators are connected in parallel to a compressor.

  As a prior art, there is a refrigeration cycle apparatus of a vehicle air-conditioning control apparatus disclosed in Patent Document 1 below. This refrigeration cycle device is equipped with two evaporators connected in parallel to the compressor for air cooling at the front and rear of the vehicle, both of which are cooled at the same time and one of them is the cooling operation It is possible to select the case to be done.

  In such a refrigeration cycle apparatus, an amount of refrigerant corresponding to the case where both of the two evaporators are used is filled in the refrigeration cycle. Therefore, when only one of the evaporators is used, the refrigerant is not used. The refrigerant from the evaporator may also flow into the driving refrigeration cycle and become overfilled, which may cause a problem that the pressure on the high pressure side greatly increases.

  Therefore, in the refrigeration cycle apparatus disclosed in Patent Document 1 below, when the cooling operation of one of the front and rear evaporators is selected, the high pressure side refrigerant exceeds the pressure and temperature of the high pressure side refrigerant in the refrigeration cycle. When the charging state is detected, the electric expansion valve on the stop side is opened to allow the refrigerant to flow also into the unused evaporator, thereby eliminating the refrigerant overcharging state in the refrigeration cycle.

Japanese Patent No. 2932314

  However, in the above-described prior art refrigeration cycle apparatus, when the refrigerant overfill state in the refrigeration cycle is detected, the expansion valve that has been closed is only opened and the refrigerant is allowed to flow to the unused evaporator. There is a problem that the refrigerant may flow at a stretch from the high pressure side where the pressure is extremely high in the overfilled state to generate a large refrigerant passing sound, and the user may feel uncomfortable.

  The present invention has been made in view of the above points, and suppresses the generation of a refrigerant passing sound at the time of valve opening for flowing the refrigerant to an unused evaporator, while increasing the pressure on the high pressure side due to the refrigerant overfilling state. An object of the present invention is to provide a refrigeration cycle apparatus capable of suppressing the above.

In order to achieve the above object, in the invention described in claim 1,
A compressor (11) for compressing and discharging the refrigerant;
A radiator (12) for radiating heat from the refrigerant discharged from the compressor (11);
First decompression means (13) for decompressing and expanding the refrigerant flowing out of the radiator (12);
A first evaporator (14) for evaporating the refrigerant decompressed by the first decompression means (13) by absorbing heat from the first external fluid;
Provided in parallel with the first decompression means (13) and switchable between a decompression mode for decompressing and expanding the refrigerant flowing out of the radiator (12) and a distribution prohibiting mode for prohibiting the circulation of the refrigerant flowing out of the radiator (12). Second decompression means (23A),
An evaporation mode that is provided in parallel with the first evaporator (14) and evaporates the refrigerant depressurized by the second depressurization means (23A) according to the presence or absence of circulation of the second external fluid that exchanges heat with the refrigerant. A second evaporator (24) that is switched to an evaporation stop mode for stopping evaporation of the refrigerant depressurized in 23A);
Pressure detecting means (16) for detecting the pressure of the refrigerant before being discharged from the compressor (11) and reduced in pressure by the first pressure reducing means (13);
Control of the mode switching of the second decompression means (23A) and the compressor (11) so that the endothermic capacity of the first evaporator (14) or the value of the related physical quantity (TE) coincides with the endothermic target value (TEO). Control means (100) for controlling the refrigerant discharge capacity of
The control means (100)
When the second decompression means (23A) is set to the flow prohibition mode and the second evaporator (24) is in the evaporation stop mode, the pressure detected by the pressure detection means (16) is equal to or higher than a predetermined pressure. in case of,
Regardless of the relationship between the endothermic capacity of the first evaporator (14) or the value of the associated physical quantity (TE) and the endothermic target value (TEO), than when the pressure detection means (16) detects a pressure equal to or higher than a predetermined pressure A first step (108) for reducing the refrigerant discharge capacity of the compressor (11);
A step performed after the first step (108), a second step of the second pressure reducing means (23A) and a vacuum mode (110),
Refrigerant discharge of the compressor (11) , which is performed after the second step , so that the endothermic capacity of the first evaporator (14) or the value (TE) of the related physical quantity matches the endothermic target value (TEO). The third step (112, 114) for controlling the capacity and setting the second decompression means (23A) in the flow prohibition mode is sequentially executed.

  According to this, when the second decompression means (23A) is set to the distribution prohibition mode and the second evaporator (24) is in the evaporation stop mode, that is, the refrigerant is distributed to the second evaporator (24). When the second evaporator (24) in which heat exchange with the second external fluid is not performed is not used, when the pressure on the high pressure side of the refrigeration cycle is higher than a predetermined pressure, Thus, the refrigerant can be circulated.

  First, in the first step (108), the refrigerant discharge capacity of the compressor (11) so that the endothermic capacity of the first evaporator (14) or the value (TE) of the related physical quantity matches the endothermic target value (TEO). It is possible to reduce the refrigerant discharge capacity of the compressor (11) and to reduce the refrigerant flow rate circulating in the refrigeration cycle, compared to the normal control in which the above control is performed.

  Next, in the second step (110) performed after the first step (108), when the pressure on the high-pressure side of the refrigeration cycle decreases with the reduction of the circulating refrigerant flow rate, the refrigerant flow path of the second decompression means (23A). And the refrigerant can be supplied to the second evaporator (24). At this time, since the second evaporator (24) is in the evaporation stop mode, the supplied liquid refrigerant does not evaporate, and most of the supplied liquid refrigerant is retained in the second evaporator (24). Can do.

  Then, in the third step (114) performed after the second step (110), the control of the refrigerant discharge capacity of the compressor (11) is returned to the normal control, and the second pressure reducing means (23A) is returned to the flow prohibition mode. Thus, the supply of the refrigerant to the second evaporator (24) can be terminated.

  Therefore, when the pressure on the high pressure side of the refrigeration cycle rises to a predetermined pressure or higher, the second pressure reducing means ( 23A) can be opened. Then, the liquid refrigerant is retained in the second evaporator (24) to reduce the circulating refrigerant flow rate in the refrigeration cycle, and the pressure on the high-pressure side rises above a predetermined pressure even if the control of the compressor (11) is returned to the normal control. Can be deterred.

  In this way, while suppressing the generation of refrigerant passing sound at the time of valve opening for flowing the refrigerant to the unused second evaporator (24), the increase in pressure on the high-pressure side of the refrigeration cycle due to the refrigerant overfill state is suppressed. can do.

  In the second aspect of the invention, the control means (100) is configured such that, in the third step (112, 114), the endothermic capacity of the first evaporator (14) or the value (TE) of the related physical quantity is the endothermic target. The refrigerant discharge capacity of the compressor (11) is controlled so as to coincide with the value (TEO), and then the second decompression means (23A) is set to the distribution prohibition mode.

  According to this, the refrigerant discharge capacity of the compressor (11) is controlled to the normal control before the supply of the liquid refrigerant to the second evaporator (24) is ended by setting the second decompression means (23A) to the flow prohibition mode. Can be returned. Therefore, the heat absorption capability of the first evaporator (14) can be recovered relatively quickly.

  According to a third aspect of the present invention, when the compressor (11) is started when the second evaporator (24) is in the evaporation stop mode, the control means (100) performs the second pressure reduction. The compressor (11) is started with the means (23A) as the decompression mode, and then the second decompression means (23A) is set in the distribution prohibition mode.

  According to this, when the refrigerant circulation to the refrigeration cycle is started in a state where the first evaporator (14) absorbs heat and the second evaporator (24) does not absorb heat, the second decompression means (23A) is provided. The second pressure reducing means (23A) can be closed after starting the compressor (11) without closing and retaining the liquid refrigerant in the second evaporator (24). Therefore, when starting the operation of the refrigeration cycle in which the second evaporator (24) does not absorb heat, the liquid refrigerant is retained in the second evaporator (24), so that the high-pressure side of the refrigeration cycle due to the refrigerant overfill state It is possible to suppress an increase in pressure.

  Further, in the invention according to claim 4, when the second evaporator (24) is switched from the evaporation mode to the evaporation stop mode, the control means (100) does not change after the switch to the evaporation stop mode. The depressurization mode of the second depressurization means (23A) is continued, and then the second depressurization means (23A) is set to the distribution prohibition mode.

  According to this, from the state where both the first evaporator (14) and the second evaporator (24) absorb heat, the first evaporator (14) absorbs heat and the second evaporator (24) absorbs heat. In the case of switching to the non-existing state, the state switching is performed without closing the second decompression means (23A), and after the liquid refrigerant is retained in the second evaporator (24), the second decompression means (23A) is closed. Can do. Therefore, when the operation of the refrigeration cycle in which the second evaporator (24) absorbs heat is changed to the operation in which the second evaporator (24) does not absorb heat, the liquid refrigerant is retained in the second evaporator (24). Thus, an increase in pressure on the high-pressure side of the refrigeration cycle due to the refrigerant overfill state can be suppressed.

  In the invention according to claim 5, when the second evaporator (24) is in the evaporation stop mode, the control device (100) sets the second pressure reducing means (23A) to the pressure reduction mode. Is characterized by controlling the second decompression means (23A) so as to intermittently form the decompression mode by alternately repeating the decompression mode and the distribution prohibition mode. According to this, it is possible to further suppress the generation of the refrigerant passing sound by reducing the flow rate of the refrigerant flowing through the second decompression means (23A), compared to the case where the decompression mode is continuously formed.

In the invention according to claim 6,
The first external fluid is air blown into the room,
Internal / external air switching that can be switched between an inside air introduction mode for supplying the first external fluid from the room to the first evaporator (14) and an outside air introduction mode for supplying the first outside fluid to the first evaporator (14) from the outside. Means (34),
When the control means (100) executes the second step (110) when the inside / outside air switching means (34) is set to the outside air introduction mode, the outside air introduction mode of the inside / outside air switching means (34) is set. After switching to the inside air introduction mode, the second decompression means (23A) is set to the decompression mode.

  When the air absorbed and cooled by the first evaporator (14) is blown into the room, the temperature of the room air is generally lower than that of the outdoor air. Therefore, when the outside air introduction mode is set, the temperature of the air supplied to the first evaporator (14) is lowered by switching the outside air introduction mode to the inside air introduction mode, and the heat absorption of the first evaporator (14). The load can be reduced. When the endothermic load of the first evaporator (14) is reduced, the refrigerant circulation flow rate of the refrigeration cycle can be reduced, so that an increase in pressure on the high pressure side can be further suppressed. Thereby, if the 2nd pressure reduction means (23A) is opened after switching outside air introduction mode to inside air introduction mode, generation | occurrence | production of a refrigerant | coolant passage sound can be suppressed further.

  Moreover, in invention of Claim 7, the 1st evaporator (14) is provided with the ventilation means (35) which ventilates the 1st external fluid, and the control means (100) has the ventilation volume of the ventilation means (35). When the amount is less than the predetermined amount, execution of the second step (110) is prohibited.

  According to this, the second step (110) can be executed to open the second decompression means (23A) when the air blowing sound of the air blowing means (35) is a predetermined amount or more and the air blowing sound is relatively large. Therefore, even if the refrigerant passing sound is generated when the second step (110) is performed, it is difficult for the user to hear the refrigerant passing sound due to the relatively large blowing sound, and the user is prevented from feeling uncomfortable due to the refrigerant passing sound. be able to.

  In the invention according to claim 8, in the refrigeration cycle apparatus (10) mounted on the vehicle, the control means (100) is configured to perform the second step (110) when the speed of the vehicle is less than a predetermined speed. It is characterized by prohibiting the execution of.

  According to this, the second step (110) can be executed to open the second decompression means (23A) when the traveling speed of the vehicle at a predetermined speed or higher is relatively loud. Therefore, even if a refrigerant passing sound is generated when the second step (110) is performed, it is difficult for the user to hear the refrigerant passing sound by the relatively loud running sound, and the user is prevented from feeling uncomfortable by the refrigerant passing sound. be able to.

  In addition, the code | symbol in the parenthesis attached | subjected to each said means is an example which shows a corresponding relationship with the specific means of embodiment description later mentioned.

It is a schematic diagram which shows schematic structure of the vehicle air conditioner 1 using the refrigerating-cycle apparatus 10 in 1st Embodiment to which this invention is applied. It is a flowchart which shows the general | schematic control action of the high pressure side pressure rise suppression of the refrigerating cycle at the time of single operation. It is a graph which shows the example of the abnormality determination threshold value of the high voltage | pressure side of a refrigerating cycle. It is a time chart which shows the operation example of the refrigerating cycle device 10, (a) is the high-pressure side pressure of a refrigerating cycle, (b) is the refrigerant discharge capacity of compressor 11, (c) is the count time of electromagnetic valve 22 open timer, (D) shows the open / close state of the electromagnetic valve 22, and (e) shows the change in the refrigerant flow rate supplied to the evaporator 14 and the change in the refrigerant flow rate supplied to the evaporator 24. It is a flowchart which shows the general | schematic control action of the high-pressure side pressure rise suppression of the refrigerating cycle at the time of the single driving | operation start in 2nd Embodiment. It is a time chart which shows the example of an action | operation of the refrigerating-cycle apparatus 10, (a) shows the driving | running state of an air conditioner, (b) shows the refrigerant | coolant discharge capacity of the compressor 11, (c) shows the change of the open / close state of the solenoid valve 22. ing. It is a flowchart which shows the general | schematic control action of the high pressure side pressure rise suppression of the refrigerating cycle at the time of the switch from the dual operation to a single operation in 3rd Embodiment. 4 is a time chart showing an operation example of the refrigeration cycle apparatus 10, (a) is an open / close state of the electromagnetic valve 22, (b) is an operating state of the rear blower 45, and (c) is a refrigerant supply to the rear evaporator 24. It shows the change in flow rate. It is a time chart which shows the example of an action | operation of the refrigerating-cycle apparatus 10 in 4th Embodiment, (a) is the open / close state of the solenoid valve 22, (b) shows the change of the refrigerant | coolant supply flow rate to the rear evaporator 24. Yes. It is a graph which shows the control action performed sequentially according to the raise of the high voltage | pressure side pressure of the refrigerating cycle in 5th Embodiment. It is a graph which shows the example of the threshold value of the refrigerating cycle high pressure side pressure which switches to forced inside air circulation. It is a graph which shows the example of the threshold value of the refrigerating cycle high pressure side pressure which opens the solenoid valve. It is a graph which shows the example of the threshold value of the refrigerating cycle high pressure side pressure which performs a high pressure cut.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. In the case where only a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those described previously. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination is not particularly troublesome.

(First embodiment)
FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle air conditioner 1 using a refrigeration cycle apparatus 10 according to a first embodiment to which the present invention is applied. A vehicle air conditioner 1 shown in FIG. 1 is an air conditioner called a dual air conditioner capable of air-conditioning a plurality of different spaces set in a passenger compartment to different temperatures.

  The vehicle air conditioner 1 includes a refrigeration cycle apparatus 10 that cools at least air supplied to a space to be air-conditioned. The refrigeration cycle apparatus 10 constitutes a refrigeration cycle in which a refrigerant circulates by a plurality of devices and piping. The refrigeration cycle apparatus 10 includes a compressor 11 that sucks, compresses, and discharges refrigerant. The compressor 11 of the present embodiment is a variable refrigerant discharge capacity type compressor capable of changing the capacity of refrigerant to be discharged.

  The refrigeration cycle apparatus 10 includes a radiator 12 that radiates heat from the high-pressure refrigerant discharged from the compressor 11 and cools the refrigerant. When a condensable refrigerant is used as the refrigerant, the radiator 12 is also called a condenser.

  The refrigerant passage provided by the refrigeration cycle apparatus 10 includes a common passage portion in which the compressor 11 and the radiator 12 are disposed, and a plurality of parallel passages provided in parallel to the common passage portion. Yes. The refrigerant passage provided by the refrigeration cycle apparatus 10 is branched into a plurality of parallel passages downstream of the radiator 12. An evaporator is provided in each of the plurality of parallel passages. The plurality of parallel passages are joined downstream of the evaporator. The joined passage communicates with the compression device 11.

  An evaporator 14 is provided in the first parallel passage. The evaporator 14 corresponds to the first evaporator in the present embodiment. The evaporator 14 includes a refrigerant passage and an air passage which is a first external fluid, and heat exchange between the refrigerant and the air is possible. The evaporator 14 cools the air with a refrigerant that evaporates inside when the compressor 11 is in operation.

  The evaporator 14 is arrange | positioned in the air-conditioning duct 31 of the indoor unit 30 arrange | positioned, for example in the front part of a vehicle interior. The evaporator 14 is a cooling heat exchanger for cooling, for example, air blown into the front seat space in the passenger compartment. The indoor unit 30 will be described later.

  The vehicle air conditioner 1 includes a temperature sensor 15 provided on the outer surface of the evaporator 14. The temperature sensor 15 can be provided by, for example, a fin temperature sensor attached to an outer fin that is thermally connected to the refrigerant pipe of the evaporator 14. The temperature sensor 15 is a temperature detection unit that detects the outer surface temperature TE of the evaporator 14 as a related physical quantity of the heat absorption capability of the evaporator 14. The temperature sensor 15 may be provided by temperature detection means called a so-called post-evaporation temperature sensor that detects the temperature of the air cooled by the evaporator 14 as a related physical quantity of the heat absorption capability of the evaporator 14.

  The refrigeration cycle apparatus 10 includes an expansion valve 13 in a first parallel passage portion between the radiator 12 and the evaporator 14. The expansion valve 13 is an expansion valve that decompresses and expands the refrigerant flowing out of the radiator 12 and supplies the refrigerant to the evaporator 14. The expansion valve 13 adjusts the refrigerant flow rate so as to maintain the refrigerant superheat degree at the outlet portion of the evaporator 14 at an appropriate value. The expansion valve 14 can be provided by a so-called temperature-sensitive expansion valve. The expansion valve 13 corresponds to the first pressure reducing means in the present embodiment.

  An evaporator 24 is provided in the second parallel passage. The evaporator 24 corresponds to the second evaporator in the present embodiment. The evaporator 24 includes a refrigerant passage and an air passage that is the second external fluid, and heat exchange between the refrigerant and the air is possible. The evaporator 24 cools the air with a refrigerant that evaporates inside when the compressor 11 is in operation.

  The evaporator 24 is arrange | positioned in the air-conditioning duct 41 of the rear indoor unit 40 arrange | positioned at the back part side side of a vehicle interior, for example. The evaporator 24 is a cooling heat exchanger for cooling, for example, air blown into the rear seat space in the passenger compartment. The indoor unit 40 will also be described later.

  The refrigeration cycle apparatus 10 includes an expansion valve 23 in the second parallel passage portion between the radiator 12 and the evaporator 24. The expansion valve 23 is an expansion valve that decompresses and expands the refrigerant flowing out of the radiator 12 and supplies the refrigerant to the evaporator 24. The expansion valve 23 adjusts the refrigerant flow rate so as to maintain the refrigerant superheat degree at the outlet portion of the evaporator 24 at an appropriate value. The expansion valve 14 can be provided by a so-called temperature-sensitive expansion valve.

  In the second parallel passage, an upstream portion of the expansion valve 23 is provided with an electromagnetic valve 22 as an opening / closing means for opening and closing the refrigerant passage. The solenoid valve 22 can intermittently flow the refrigerant in the second parallel passage. Therefore, when the electromagnetic valve 22 is open, the refrigerant flows through the second parallel passage and the evaporator 24 provided there. On the other hand, when the electromagnetic valve 22 is closed, the refrigerant does not flow through the second parallel passage and the evaporator 24 provided there.

  Second decompression means in which the configuration comprising the electromagnetic valve 22 and the expansion valve 23 can switch between a decompression mode for decompressing and expanding the refrigerant flowing out of the radiator 12 and a distribution prohibiting mode for prohibiting the circulation of the refrigerant flowing out of the radiator 12. 23A.

  Specifically, in the refrigerant passage between the radiator 12 and the expansion valve 13, the pressure for detecting the refrigerant pressure in the refrigerant passage is between the refrigerant outlet of the radiator 12 and the branch points of the plurality of parallel passages. A sensor 16 is provided. The pressure sensor 16 corresponds to pressure detection means for detecting the refrigerant pressure before being discharged from the compressor 11 and reduced in pressure by the expansion valve 13. The pressure sensor 16 is a high pressure side pressure detecting means for detecting the pressure on the high pressure side of the refrigeration cycle.

  The indoor unit 30 includes an air-conditioning duct 31 that forms an air passage that guides conditioned air into the vehicle interior, a centrifugal blower 35 that generates an air flow in the air-conditioning duct 31, and cooling air that flows through the air-conditioning duct 31. The above-described evaporator 14 and the heater core 38 that is a heat exchanger for heating for reheating the air flowing in the air conditioning duct 31 are configured.

  The air conditioning duct 31 is disposed, for example, in the front part of the vehicle interior. The most upstream side (windward side) of the air-conditioning duct 31 is a portion constituting an inside / outside air (suction port) switching box, and an inside air suction port 32 for taking in cabin air (hereinafter sometimes referred to as inside air) and outside cabin air It has an outside air inlet 33 for taking in (hereinafter sometimes referred to as outside air).

  Inside / outside air suction port 32 and outside air suction port 33, an inside / outside air (suction port) switching damper 34 (inside / outside air switching door) is rotatably attached. The inside / outside air switching damper 34 is driven by an actuator such as a servo motor to switch the suction port mode between an inside air circulation mode (an inside air introduction mode) and an outside air introduction mode. The inside / outside air switching damper 34 corresponds to inside / outside air switching means for switching the air introduction mode into the air conditioning duct 31 between the inside air introduction mode and the outside air introduction mode.

  The most downstream side (leeward side) of the air-conditioning duct 31 is a portion constituting the air outlet mode switching portion, and a defroster opening portion, a face opening portion, a foot opening portion and the like which are not shown are formed. Moreover, the part which comprises a blower outlet mode switching part is provided with the blowout mode door which can set the various blowout modes by adjusting the opening-and-closing state of each above-mentioned opening part.

  The blower 35 includes a centrifugal fan 36 that is rotatably accommodated in a scroll case that is integrally formed with the air conditioning duct 31, and a blower motor 37 that rotationally drives the centrifugal fan 36. The blower motor 37 controls the amount of air blown (the rotational speed of the centrifugal fan 31) based on the blower voltage applied via the blower drive circuit. The blower 35 is a blowing unit that blows air, which is the first external fluid, to the evaporator 14.

  The heater core 38 is disposed downstream of the evaporator 14 in the air conditioning duct 31, and an air mix damper (air mix door) (not shown) is rotatably attached to the air upstream side of the heater core 38. Yes. The air mix damper adjusts the ratio of the amount of air (warm air) passing through the heater core 38 and the amount of air (cold air) that bypasses the heater core 38 according to the rotation position thereof, and the air blowing temperature blown out into the vehicle interior Adjust.

  The indoor unit 40 is an air conditioning duct 41 that forms an air passage that guides conditioned air into the vehicle interior, a centrifugal blower 45 that generates an air flow in the air conditioning duct 41, and cooling air that flows through the air conditioning duct 41. The above-described evaporator 24 and the heater core 48 that is a heat exchanger for heating for reheating the air flowing in the air conditioning duct 41 are configured.

  The air conditioning duct 41 is disposed, for example, at a site on the side of the rear part in the vehicle interior. The indoor unit 40 has substantially the same configuration as the indoor unit 30. In the air conditioning unit 30, whether or not the air that is the second external fluid that exchanges heat with the refrigerant in the evaporator 24 is switched by switching between the driving state and the stopped state of the blower 45. When the blower 45 is driven, the evaporator 24 is in an evaporation mode in which the refrigerant decompressed by the second decompression means 23A is evaporated by absorbing heat from the air. When the blower 45 is stopped, the evaporator 24 is in an evaporation stop mode in which the evaporation of the refrigerant decompressed by the second decompression means 23A is stopped.

  The air-conditioning control device 100 corresponding to the control means includes a microcomputer including a CPU, a ROM, a RAM, and the like (not shown). Sensor signals from the sensors 15, 16 and the like are configured to be A / D converted by an input circuit (not shown) in the control device 100 and then input to the microcomputer.

  The control device 100, based on an input signal from each switch of the control panel (not shown) and an input signal from each sensor including the sensors 15 and 16, etc., a blower rotation speed adjustment signal, an operation control signal for each damper, a compression A capacity adjustment signal, a solenoid valve opening / closing signal, and the like are output to control the blowers 35 and 45, the inside / outside air switching damper 34, the compressor 11, the solenoid valve 22, and the like.

  In FIG. 1, the flow of the refrigerant when the compressor 11 is operated to air-condition both the front seat space and the rear seat space in the vehicle interior is indicated by arrows (so-called indoor units of the air conditioner). 30 and 40 show the refrigerant flow during dual operation). The control device 100 is configured so that the outer surface temperature TE of the evaporator 14 detected by the temperature sensor 15 matches the target temperature TEO of the evaporator 14 (corresponding to the endothermic target value of the evaporator 14) (as close as possible). Then, the refrigerant discharge capacity of the compressor 11 is adjusted. The target temperature TEO is the outer surface temperature of the evaporator 14 necessary to achieve the target air temperature TAO required for air conditioning (for example, temperature control, humidity control, anti-fogging, etc.). It is.

  During dual operation, the refrigerant is decompressed by the expansion valve 13 and evaporated in the evaporator 14. As a result, the refrigerant cools the air supplied to the front seat space and air-conditions the front seat space. On the other hand, the refrigerant that has passed through the opened electromagnetic valve 22 is decompressed by the expansion valve 23 and is evaporated in the evaporator 24. As a result, the refrigerant cools the air supplied to the rear seat space and air-conditions the rear seat space.

  In contrast, when the solenoid valve 22 is closed and the operation of the blower 45 is stopped, only the front seat space in the vehicle interior is air-conditioned (so-called single operation of only the indoor unit 30 of the air conditioner). . During single operation, the refrigerant is decompressed by the expansion valve 13 and evaporated in the evaporator 14. As a result, the refrigerant cools the air supplied to the front seat space and air-conditions the front seat space. On the other hand, the refrigerant is not supplied to the evaporator 24 by the closed electromagnetic valve 22, and the blowing in the air conditioning duct 41 is stopped by the stopped blower 45. As a result, the rear seat space is not air-conditioned.

  Next, operation control for suppressing high-pressure side pressure increase in the refrigeration cycle during single operation of the vehicle air conditioner 1 will be described based on the above configuration. In the refrigeration cycle apparatus including the two evaporators as described above, an amount of refrigerant corresponding to the dual operation is filled in the refrigeration cycle. Therefore, at the time of the single operation described above, the refrigerant circulating in the refrigeration cycle is overfilled, which may cause a problem that the pressure on the high pressure side increases greatly. The control for preventing this problem is the high-pressure side pressure rise suppression operation control described below.

  FIG. 2 is a flowchart showing a schematic control operation for suppressing high-pressure side pressure increase in the refrigeration cycle during single operation.

  As shown in FIG. 2, when the air conditioner switch on the control panel (not shown) is turned on and the single operation that does not perform the air conditioning operation by the rear indoor unit 40 is selected, Based on the pressure information detected by the sensor 16, the refrigerant pressure on the high-pressure side of the refrigeration cycle is detected (step 101).

  Next, it is determined whether the pressure on the high pressure side of the refrigeration cycle detected in step 101 is normal or abnormal (step 102). An abnormal pressure on the high pressure side of the refrigeration cycle means that the refrigerant pressure on the high pressure side is higher than a predetermined pressure. As shown in FIG. 3, for example, as shown in FIG. 3, the threshold value for determining whether the pressure is normal or abnormal can be a predetermined pressure having hysteresis.

  If it is determined in step 102 that the pressure on the high pressure side is abnormal, the abnormality flag is set to ON (step 103), and the process proceeds to step 104. If it is determined in step 102 that the pressure on the high pressure side is normal, the process proceeds to step 104 as it is.

  In step 104, it is determined whether or not the abnormality flag is ON. In the first step 102, when the pressure on the high pressure side is determined to be normal and the abnormality flag is not set and is OFF, or when the abnormality flag is turned OFF in step 115 to be described later, the high pressure side is detected in step 102 immediately thereafter. Is determined to be normal, it is determined in step 104 that the abnormality flag is OFF.

  If it is determined in step 104 that the abnormality flag is OFF, the compressor 11 is normally controlled. Further, the rear solenoid valve 22 is closed (if it is closed, it is maintained) (step 105). The normal control of the compressor 11 is the refrigerant discharge of the compressor 11 so that the outer surface temperature TE of the evaporator 14 detected by the temperature sensor 15 matches the target temperature TEO of the evaporator 14 (as close as possible). It is a control that adjusts the capacity. When step 105 is executed, the process returns to step 101.

  If it is determined in step 104 that the abnormality flag is ON, it is determined whether or not the rear solenoid valve 22 is open (step 106). If the solenoid valve 22 is in the closed state in step 106, it is determined whether the refrigerant discharge capacity of the compressor 11 has already been reduced (step 107). Here, the reduction of the refrigerant discharge capacity of the compressor 11 is to reduce the refrigerant discharge capacity as compared with the normal control of the compressor 11 performed in step 105.

  When it is determined in step 107 that the refrigerant discharge capacity of the compressor 11 has not been reduced, that is, during the so-called normal single operation in which the electromagnetic valve 22 is closed and the compressor 11 is normally controlled. If it is determined, the refrigerant discharge capacity of the compressor 11 is reduced from that during normal control (step 108), and the process proceeds to step 109. If it is determined in step 107 that the refrigerant discharge capacity of the compressor 11 has already been reduced, the process proceeds to step 109 as it is.

  In step 109, it is determined whether or not the count time of the timer means that started counting when the refrigerant discharge capacity is reduced by executing step 108 has passed a predetermined time (α seconds, for example, 5 seconds). . If it is determined that the predetermined time has not elapsed since the execution of step 108, the process returns to step 101.

  If it is determined in step 109 that a predetermined time has elapsed since step 108 was executed, the rear solenoid valve 22 is opened (step 110), and the process returns to step 101.

  If it is determined in step 106 that the solenoid valve 22 is in the open state, it is determined whether or not the control of the refrigerant discharge capacity of the compressor 11 has returned to the normal control (step 111).

  If it is determined in step 111 that the control of the refrigerant discharge capacity of the compressor 11 has not been returned to the normal control, the refrigerant discharge capacity control of the compressor 11 is set to the normal control (step 112), and the process proceeds to step 113. If it is determined in step 111 that the control of the refrigerant discharge capacity of the compressor 11 has already been returned to the normal control, the process proceeds to step 113 as it is.

  In step 113, it is determined whether or not the count time of the timer means that started counting when step 110 is executed to open the solenoid valve 22 has passed a predetermined time (β seconds, for example, 5 seconds). . If it is determined that the predetermined time has not elapsed since the execution of step 110, the process returns to step 101.

  If it is determined in step 113 that a predetermined time has elapsed since step 110 is executed, the rear solenoid valve 22 is closed (step 114), and the abnormality flag is turned OFF (step 115). Return to 101.

  According to the above-described configuration and operation control, the control device 100 determines that the refrigerant pressure detected by the pressure sensor 16 is equal to or higher than a predetermined pressure during the single operation of only the front indoor unit 30 in which the electromagnetic valve 22 is closed and the blower 45 is stopped. When it is determined that the pressure on the high pressure side is abnormal, the refrigerant discharge capacity of the compressor 11 is reduced in step 108 compared to the normal control (when abnormality is first determined in step 102), and then for a predetermined time. After the elapse of time, the electromagnetic valve 22 is opened in step 110.

  As a result, the discharge capacity of the compressor 11 is reduced and the pressure on the high-pressure side is reliably reduced over a predetermined time, and then the refrigerant flowing out of the radiator 12 is also circulated into the second parallel passage. To supply. Therefore, since the solenoid valve 22 is opened when the pressure on the high pressure side of the refrigeration cycle is reduced and the pressure difference between the high pressure side and the low pressure side is reduced, the refrigerant passing amount per time when the valve is opened is reduced. It can suppress and generation | occurrence | production of refrigerant | coolant passage sound can be suppressed.

  That is, by reducing the refrigerant circulation flow rate in the refrigeration cycle and opening the solenoid valve 22 when the refrigerant flow rate passing through the solenoid valve 22 is reduced when the solenoid valve 22 is opened, the refrigerant passing sound is generated. Can be suppressed.

  When the refrigerant is supplied to the evaporator 24 in this way, the blower 45 is stopped, and the flow of air as the second external fluid to the evaporator 24 is stopped, so that the liquid refrigerant that has flowed into the evaporator 24 Is hard to evaporate and stays in the evaporator 24. This is a so-called sleeping state. As the liquid refrigerant staying in the evaporator 24 increases, the flow rate of the refrigerant circulating through the common passage portion of the refrigeration cycle and the first parallel passage decreases.

  In this way, after reducing the refrigerant flow rate circulating in the common passage portion of the refrigeration cycle and the first parallel passage, the refrigerant discharge capacity control of the compressor 11 is returned to the normal control in step 112, and the electromagnetic flow in step 114. The valve 22 is closed and the normal single operation is resumed. Therefore, an increase in pressure on the high pressure side due to the refrigerant overfill state in the refrigeration cycle can be suppressed.

  Here, in step 108, regardless of the relationship between the evaporator outer surface temperature TE, which is the value of the related physical quantity of the heat absorption capability of the evaporator 14, and the target evaporator temperature TEO, which is the endothermic target value, the pressure sensor 16 has a predetermined pressure. This corresponds to the first step in the present embodiment in which the refrigerant discharge capacity of the compressor 11 is reduced more than when the above pressure is detected.

  Step 110 corresponds to the second step of the present embodiment in which, after the first step, the electromagnetic valve 22 is opened and the second pressure reducing means 23A is set in the pressure reducing mode.

  Further, in step 112 and step 114, after the second step, the evaporator outer surface temperature TE, which is the value of the related physical quantity of the heat absorption capability of the evaporator 14, is made to coincide with the target evaporator temperature TEO which is the endothermic target value. This corresponds to the third step of the present embodiment in which the refrigerant discharge capacity of the compressor 11 is controlled and the electromagnetic valve 22 is closed to place the second decompression means 23A in the flow prohibition mode.

  Further, the controller 100 returns the refrigerant discharge capacity control of the compressor 11 to the normal control in step 112 immediately after opening the electromagnetic valve 22 in step 110, and after the predetermined time has elapsed after opening the electromagnetic valve 22, in step 114. The solenoid valve 22 is closed to return to normal single operation.

  In the third step, the refrigerant discharge capacity of the compressor 11 is set so that the evaporator outer surface temperature TE, which is the value of the related physical quantity of the endothermic capacity of the evaporator 14 in step 112, coincides with the target evaporator temperature TEO which is the endothermic target value. After that, the electromagnetic valve 22 is closed to place the second decompression means 23A in the flow prohibition mode.

  According to this, the refrigerant discharge capacity control of the compressor 11 is started before the supply of the liquid refrigerant to the evaporator 24 is finished (almost a predetermined time β seconds) with the electromagnetic valve 22 closed and the second decompression means 23A set in the flow prohibition mode. Can be returned to normal control. Therefore, the heat absorption capability (air cooling capability) of the evaporator 14 can be recovered relatively quickly.

  Further, a predetermined time β seconds or more elapses from when the electromagnetic valve 22 is opened at step 110 to when the electromagnetic valve 22 is closed at step 114. That is, the liquid refrigerant is supplied to the evaporator 24 over a period of β seconds or more. Therefore, a relatively large amount of liquid refrigerant can be reliably retained in the evaporator 24.

  FIG. 4 is a time chart showing an operation example of the refrigeration cycle apparatus 10 of the present embodiment. (A) is the high-pressure side pressure of the refrigeration cycle, (b) is the refrigerant discharge capacity control signal value (substantially refrigerant discharge capacity) to the compressor 11, and (c) is the timer means (electromagnetic) used for the determination in step 109. (D) is the open / close state of the solenoid valve 22, (e) is the refrigerant flow rate supplied to the front evaporator 14 (the refrigerant flow rate through the expansion valve 13), and the rear evaporator 24. The change of the supplied refrigerant | coolant flow rate (expansion valve 23 passage refrigerant | coolant flow rate) is shown.

  Step 108 is executed at time T1, step 110 is executed at time T2, step 112 is executed at time T3, and step 115 is executed at time T4. Therefore, the elapsed time from T1 to T2 is approximately α seconds, and the elapsed time from T2 to T4 is approximately β seconds.

  In this embodiment, when step 108 is executed to output a refrigerant discharge capacity reduction command of the compressor 11, the elapse of a predetermined time is confirmed in step 109, and then the electromagnetic valve 22 is opened in step 110. This is because there is a time lag between the change of the output signal to the compressor 11 and the actual change of the refrigerant circulation flow rate in the refrigeration cycle, so that the solenoid valve 22 is opened when the refrigerant circulation flow rate can be reliably reduced. Step 109 was provided.

  Therefore, after executing step 108, the criterion for determining whether or not the state where step 110 can be executed has been reached is not limited to the passage of a predetermined time.

  For example, the amount of change in the outer surface temperature TE of the evaporator 14 may be used. The electromagnetic valve 22 may be opened when the difference ΔTE is equal to or higher than a predetermined temperature by looking at the difference in TE before and after reducing the discharge capacity of the compressor 11.

  Further, for example, it may be the circulating refrigerant flow rate of the refrigeration cycle. The difference in refrigerant flow rate Gr before and after the discharge capacity of the compressor 11 is reduced (the absolute value of the flow rate reduction amount). When the difference ΔGr exceeds a predetermined amount, the solenoid valve 22 is opened. It may be a thing. Further, the solenoid valve 22 may be opened when the circulating refrigerant flow rate Gr after reducing the discharge capacity of the compressor 11 becomes equal to or less than a predetermined amount instead of the refrigerant flow rate Gr difference ΔGr.

  Further, for example, it may be a high-pressure refrigerant pressure value (for example, a detection value of the pressure sensor 16) of the refrigeration cycle. By looking at the difference in refrigerant pressure Ph before and after reducing the discharge capacity of the compressor 11 (the absolute value of the pressure decrease amount), the solenoid valve 22 is opened when the difference ΔPh becomes equal to or greater than a predetermined pressure. It may be a thing. Further, instead of the difference ΔPh in the refrigerant pressure Ph, the solenoid valve 22 may be opened when the refrigerant pressure Ph after reducing the discharge capacity of the compressor 11 becomes equal to or lower than a predetermined pressure.

  Further, for example, it may be a high / low differential pressure (a differential pressure between the high pressure side pressure and the low pressure side pressure) of the refrigeration cycle. The electromagnetic valve 22 may be opened when the pressure difference ΔPhl after reducing the discharge capacity of the compressor 11 becomes equal to or lower than a predetermined pressure.

(Second Embodiment)
Next, a second embodiment will be described based on FIG. 5 and FIG.

  In the second embodiment, the liquid refrigerant stays in the evaporator 45 of the rear indoor unit 40 when the single operation of the front indoor unit 30 of the vehicle air conditioner 1 is started, as compared with the first embodiment. The difference is that control for suppressing the increase in pressure on the high pressure side due to the refrigerant overfill state in the refrigeration cycle is added. In addition, about the part similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 5, in the present embodiment, in the present embodiment, when the air conditioner switch of the control panel (not shown) is turned on and the single operation that does not perform the air conditioning operation by the rear indoor unit 40 is selected. First, it is determined whether or not the compressor 11 is being gradually changed (step 201).

  Here, the gradual change starting of the compressor 11 will be described. The gradual change start control of the compressor 11 means that when the vehicle air conditioner 1 is started in the single operation mode, even if the outer surface temperature TE of the evaporator 14 and the target evaporator temperature TEO are greatly deviated from each other, the compression is performed. In this control, the refrigerant discharge capacity of the machine 11 is not increased at once to the maximum capacity, but is gradually increased from the low discharge capacity lower than the maximum discharge capacity.

  Specifically, when the single operation not performing the air conditioning operation by the rear indoor unit 40 is selected, the air conditioner switch of the control panel (not shown) is turned on, or the air conditioner of the control panel (not shown) When the switch is turned on and single operation without air conditioning operation by the rear indoor unit 40 is selected, an ignition switch for a vehicle (a start switch that enables vehicle travel in a vehicle equipped with a travel electric motor) ) Is turned on, for example, as shown in FIG. 6B, the refrigerant discharge capacity of the compressor 11 is controlled.

  As shown in FIG. 6A, when the air conditioner 1 is turned on in a single operation, the compressor 11 is started with an intermediate discharge capacity lower than the maximum discharge capacity as shown in FIG. 6B. After maintaining the state for a while, the discharge capacity is gradually increased to shift to the maximum discharge capacity (discharge capacity for making TE coincide with TEO).

  The state of the compressor 11 from the time T5 to the time T6 in FIG. 6B is a state in which the compressor 11 is being gradually activated. In step 201, it is determined whether or not the compressor 11 is in the above-described gradual change starting.

  If it is determined in step 201 that the compressor 11 is being gradually activated, it is determined whether or not the rear solenoid valve 22 is open (step 202). If the solenoid valve 22 is closed, the solenoid valve 22 is opened (step 203), and the process returns to step 201. If it is determined in step 202 that the solenoid valve 22 has already been opened, the process returns to step 201 as it is.

  If it is determined in step 201 that the compressor 11 is not being gradually started (the gradual change start control has been completed and the normal control has been started), the rear solenoid valve 22 is closed (step 204), and the step Return to 201.

  According to the above-described operation control, the control device 100 is configured such that when the vehicle air conditioner 1 is turned on in a single operation, that is, when the blower 45 is stopped and the evaporator 24 is in the evaporation stop mode. 11 is started, the electromagnetic valve 22 is opened, the second pressure reducing means 23A is set to the pressure reducing mode, the compressor 11 is started, and the solenoid valve 22 is closed after a predetermined time (at the end of gradual change starting). Then, the second decompression means 23A is set to the distribution prohibition mode (see FIG. 6C).

  According to this, when the refrigerant circulation to the refrigeration cycle is started in the state where the evaporator 14 absorbs heat and the evaporator 24 does not absorb heat, the compressor 11 is started without closing the solenoid valve 22 to evaporate. After the liquid refrigerant is retained in the vessel 24, the electromagnetic valve 22 is closed. Therefore, when starting the operation of the refrigeration cycle in which the evaporator 24 does not absorb heat, the liquid refrigerant is retained in the evaporator 24, thereby suppressing the pressure increase on the high-pressure side of the refrigeration cycle due to the refrigerant overfill state. it can.

  When the solenoid valve 22 is opened and the refrigerant is supplied to the evaporator 24, the refrigerant discharge capacity of the compressor 11 is suppressed. Therefore, it is possible to suppress the generation of the passage sound of the refrigerant passing through the second decompression means 23A.

  In addition, after the air-conditioning apparatus 1 is started, the above-described control is performed, and after the gradual change start control of the compressor 11 is finished and the control is shifted to the normal control, the high-pressure side described in the first embodiment with reference to FIG. Control to suppress pressure rise. Therefore, even if the liquid refrigerant cannot be sufficiently stored in the evaporator 24 at the time of starting the single operation of the vehicle air conditioner 1, it is possible to suppress an increase in pressure on the high pressure side due to the refrigerant overfill state in the refrigeration cycle. it can.

  The effect of retaining liquid refrigerant in the evaporator 24 at the time of single operation start of the vehicle air conditioner 1 and suppressing the pressure increase on the high pressure side due to the refrigerant overfill state in the refrigeration cycle is to gradually start the compressor 11. Even if it is not (even when the maximum discharge capacity is set at once), it is possible to obtain it.

  Further, in the present embodiment, the case where the control described with reference to FIG. 5 is combined with the control described with reference to FIG. 2 in the first embodiment has been described. Even without being combined with the control described in the first embodiment, it is possible to suppress an increase in pressure on the high-pressure side due to the refrigerant overfill state in the refrigeration cycle.

(Third embodiment)
Next, a third embodiment will be described based on FIG. 7 and FIG.

  Compared with the first embodiment described above, the third embodiment changes the operation of the vehicle air conditioner 1 from dual operation by both the front air conditioning unit 30 and the rear air conditioning unit 40 to air conditioning by the rear air conditioning unit 40. When stopping and switching to the single operation of the front indoor unit 30, control is performed so that the liquid refrigerant stays in the evaporator 45 of the rear indoor unit 40 and the pressure increase on the high pressure side due to the refrigerant overfill state in the refrigeration cycle is suppressed. The added point is different. In addition, about the part similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 7, in the present embodiment, when the air conditioner switch of a control panel (not shown) is turned on and the vehicle air conditioner 1 is operated, the control device 100 first operates the air conditioner 1. Is determined to be front / rear dual operation or front-only single operation (step 301).

  When it is determined in step 301 that the operation state is dual operation, it is determined whether or not the operation state of the air conditioner 1 has been switched to single operation with only the front (step 302), and the operation state must be switched to single operation. If so, the process returns to step 301. In step 302, the air conditioner switch of the rear indoor unit 40 is turned off and a command for switching from dual operation to single operation is monitored.

  When a switching command from dual operation to single operation is detected in step 302, the flag is set to 1 (step 303), and the operation mode of the air conditioner 1 is set to the single operation mode (step 304). In step 304, the blower 45 of the rear indoor unit 40 is stopped. However, here, the electromagnetic valve 22 is not closed but is kept open. After executing step 304, the process returns to step 301.

  When it is determined in step 301 that the operation state of the air conditioner 1 is single operation, it is determined whether or not the flag is set to 1 (step 305). If it is determined in step 305 that the flag is set to 1, the count time of the timer means that started counting when step 304 is executed and single operation is started with the solenoid valve 22 open. Then, it is determined whether or not a predetermined time (γ seconds, for example, 5 seconds) has passed (step 306).

  If it is determined in step 306 that the predetermined time has not elapsed since step 304 was executed, the process returns to step 301. If it is determined in step 306 that a predetermined time has elapsed since step 304 was executed, the rear solenoid valve 22 is closed (step 307), and the flag is set to 0 (step 308). Return to

  If it is determined in step 305 that the operation state is single operation and the flag is set to 0, the process returns to step 301 as it is.

  According to the above-described operation control, the control device 100 is operated when the vehicle air conditioner 1 is switched from the dual operation to the single operation during operation, that is, the blower 35 and the blower 45 are both driven, and the refrigeration cycle apparatus 10 is driven. When the air conditioning operation of the rear indoor unit 40 is stopped when the electromagnetic valve 22 is in an open operation state, the rear blower 45 is quickly stopped, but the electromagnetic valve 22 remains open for a predetermined time. After that, close it.

  As illustrated in FIG. 8, when switching from dual operation to single operation at time T7, as shown in FIG. 8B, when the operation state is switched (to T7), blowing of the rear blower 45 stops. Then, as shown in FIG. 8A, the rear solenoid valve 22 is closed at a time T8 when a predetermined time has elapsed from the time T7. As a result, as shown in FIG. 8C, the liquid refrigerant is supplied to the evaporator 24 through the second decompression means 23 </ b> A also during T <b> 7 to T <b> 8. Most of the liquid refrigerant supplied to the evaporator 24 stays in the evaporator 24 because air, which is an external fluid, does not flow through the evaporator 24.

  At time T7, the determination at step 302 is made, and steps 303 and 304 are executed. At time T8, steps 307 and 308 are executed. Therefore, the elapsed time from T7 to T8 is approximately γ seconds.

  According to this, when switching from a state where heat is absorbed by both evaporators 14 and 24 to a state where heat is absorbed by evaporator 14 and heat is not absorbed by evaporator 24, electromagnetic valve 22 is not closed and evaporator 24 is closed. Is stopped and the liquid refrigerant is retained in the evaporator 24, and then the solenoid valve 22 is closed. Therefore, when switching to the operation of the refrigeration cycle in which the evaporator 24 does not absorb heat, the liquid refrigerant is retained in the evaporator 24, thereby suppressing an increase in pressure on the high-pressure side of the refrigeration cycle due to the refrigerant overfill state. .

  Further, when the air conditioner 1 is switched from the dual operation to the single operation, the above-described control is performed, and after shifting to the normal single operation, the pressure increase on the high pressure side described with reference to FIG. 2 in the first embodiment. Control to suppress this. Therefore, even if the liquid refrigerant cannot be sufficiently stored in the evaporator 24 when the vehicle air conditioner 1 is shifted from the dual operation to the single operation, the pressure increase on the high pressure side due to the refrigerant overfill state in the refrigeration cycle. Can be suppressed.

  In the present embodiment, the case where the single operation transition control described with reference to FIG. 7 is combined with the control described with reference to FIG. 2 in the first embodiment has been described. Even if the control is not combined with the control described in the first embodiment, it is possible to suppress an increase in pressure on the high pressure side due to the refrigerant overfill state in the refrigeration cycle.

  Moreover, not only the control at the time of the single operation transition described with reference to FIG. 7 and the control described with reference to FIG. 2 in the first embodiment are combined, but also described with reference to FIG. 5 in the second embodiment. You may combine the controls at the start of single operation.

(Fourth embodiment)
Next, a fourth embodiment will be described based on FIG.

  The fourth embodiment is different from the first embodiment described above in the open state of the electromagnetic valve 22 that is opened in order to retain the liquid refrigerant in the rear evaporator 24. In addition, about the part similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In the present embodiment, the control device 100 intermittently opens the electromagnetic valve 22 from the time when the electromagnetic valve 22 is opened at step 110 shown in FIG. 2 to the time when the electromagnetic valve 22 is closed at step 114. .

  That is, when the pressure on the high-pressure side of the refrigeration cycle becomes a predetermined pressure or more during single operation of the air conditioner 1, the refrigerant discharge capacity of the compressor 22 is reduced to reduce the refrigerant circulation flow rate, and the electromagnetic valve 22 When a state is formed in which the flow rate of the refrigerant passing through the electromagnetic valve 22 becomes small when the valve is opened, the electromagnetic valve 22 is opened. When the electromagnetic valve 22 is opened, the open state and the closed state of the electromagnetic valve 22 are alternately repeated so that the electromagnetic valve 22 is intermittently opened and the liquid refrigerant is allowed to sleep in the evaporator 24. .

  In other words, when the evaporator 24 is in the evaporation stop mode and the second decompression means 23A is in the decompression mode, the control device 100 alternately repeats the decompression mode and the distribution prohibition mode, The second decompression means 23A is controlled so as to intermittently form the decompression mode.

  According to the above-described operation control, it is possible to reduce the refrigerant flow rate per time flowing through the second decompression means 23A, compared to when the electromagnetic valve 22 is continuously opened.

  For example, as shown in FIG. 9 (a), when the solenoid valve 22 is operated so as to alternate between the open state and the closed state from time T9 to time T10, as shown in FIG. 9 (b). The flow rate of the refrigerant flowing into the second parallel passage (rear side) is reduced. The refrigerant flow rate indicated by the broken line in FIG. 9B is the refrigerant flow rate flowing into the second parallel passage when the electromagnetic valve 22 is continuously opened from T9 to T10. The maximum flow rate value can be made lower in the refrigerant flow rate of the present embodiment shown by the solid line than in this refrigerant flow rate.

  Thus, when the electromagnetic valve 22 is opened and the refrigerant is supplied to the evaporator 24, it is possible to further suppress the generation of the refrigerant passing sound of the second decompression means 23A.

  Here, when the pressure on the high pressure side of the refrigeration cycle is equal to or higher than a predetermined pressure during single operation of the air conditioner 1, the electromagnetic discharge is performed after the refrigerant discharge capacity of the compressor 22 is reduced and the refrigerant circulation flow rate is reduced. The open state control of the valve 22 has been described. On the other hand, when the pressure on the high pressure side of the refrigeration cycle becomes a predetermined pressure or more during single operation, the solenoid valve 22 is opened intermittently without reducing the refrigerant discharge capacity of the compressor 22. Even if the control is performed, the effect of suppressing the generation of the refrigerant passing sound can be obtained.

  The open state control of the electromagnetic valve 22 that opens the electromagnetic valve 22 intermittently is also effective when applied to the opening of the electromagnetic valve 22 from the execution of step 203 to the execution of step 204 in FIG. .

  Further, even if the compressor 11 is not gradually started at the time of starting the single operation as in the second embodiment described with reference to FIG. The open state control of the electromagnetic valve 22 described in the embodiment can be applied. When the compressor 11 is not gradually changed and started, since the refrigerant circulation flow rate is relatively large, it is extremely effective from the viewpoint of suppressing the generation of refrigerant passing sound to perform the open state control that opens the electromagnetic valve 22 intermittently. It is.

  The open state control for intermittently opening the electromagnetic valve 22 described in the present embodiment is performed when the electromagnetic valve 22 from the execution of step 304 shown in FIG. 7 to the execution of step 307 is opened. Is also effective when applied.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIGS.

  Compared to the first embodiment described above, the fifth embodiment forces the indoor / outdoor air switching door 34 of the indoor unit 30 before opening the solenoid valve 22 to retain the liquid refrigerant in the evaporator 24. The point is that it is the inside air introduction mode. In addition, about the part similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In the present embodiment, when the vehicle air conditioner 1 is in single operation, the control device 100 determines that the refrigerant pressure on the high-pressure side of the refrigeration cycle detected in step 101 is the step 102 in addition to the execution of the control flow shown in FIG. It is also determined whether or not the pressure on the high pressure side is equal to or higher than a predetermined value lower than a determination value for determining whether the pressure on the high pressure side is normal or abnormal.

  If the pressure on the high-pressure side is equal to or higher than a predetermined value that is lower than the determination value for determining whether the pressure is normal or abnormal (it is a normal value but a relatively high pressure), the pressure on the high-pressure side is Even if it is determined to be normal, the inside / outside air switching damper 34 is forcibly set to the inside air introduction mode. When the inside air introduction mode is selected, the inside air introduction mode is maintained, and when the outside air introduction mode is selected, the mode is changed to the inside air introduction mode regardless of the selection mode.

  For example, when the pressure threshold value shown in FIG. 11 is set as the determination value and the high-pressure side pressure of the refrigeration cycle is equal to or higher than this threshold value, the control device 100 changes the air introduction mode into the air conditioning duct 31 between the inside air introduction mode and the outside air introduction The inside / outside air switching damper 34, which is an inside / outside air switching means for switching between modes, is forcibly set to an inside air introduction mode (an inside air circulation mode (REC mode)).

  The control device 100 opens the solenoid valve 22 after reducing the discharge capacity of the compressor 11 when the pressure threshold value shown in FIG. 12 is used as a determination value and the high-pressure side pressure of the refrigeration cycle is equal to or higher than this threshold value. Then, the liquid refrigerant is retained in the evaporator 24.

  Further, the control device 100 uses the pressure threshold value shown in FIG. 13 as a determination value, and stops the refrigerant circulation by stopping the compressor 11 when the high-pressure side pressure of the refrigeration cycle is equal to or higher than this threshold value (so-called high-pressure cut). To do).

  By controlling in this way, as shown in FIG. 10, when the pressure on the high-pressure side of the refrigeration cycle increases, before the pressure on the high-pressure side is determined to be abnormal, The air introduction mode of the switching box is forcibly set to the inside air introduction mode.

  When air that has been absorbed and cooled by the evaporator 14 is blown into the room to air-condition the vehicle interior, the temperature in the vehicle interior is generally lower than that of the air outside the vehicle interior. Therefore, when the inside / outside air switching damper 34 of the inside / outside air switching box is set to the outside air introduction mode, the temperature of the air supplied to the evaporator 14 is lowered by forcibly switching the outside air introduction mode to the inside air introduction mode. Thus, the heat absorption load (cooling load) of the evaporator 14 can be reduced. When the heat absorption load of the evaporator 14 is reduced, the refrigerant circulation flow rate of the refrigeration cycle can be reduced.

  In this way, even if the cooling load of the evaporator 14 is reduced and the refrigerant circulation flow rate is reduced to suppress the increase in the high-pressure side pressure, the high-pressure side pressure rises and the high-pressure side pressure is determined to be abnormal. In this case, as described in the first embodiment, after the discharge capacity of the compressor 11 is reduced, the electromagnetic valve 22 is opened, and the liquid refrigerant is retained in the evaporator 24 to reduce the refrigerant circulation flow rate.

  That is, when executing step 110 in FIG. 2 when the inside / outside air switching damper 34 is set to the outside air introduction mode, first, the outside air introduction mode of the inside / outside air switching damper 34 is switched to the inside air introduction mode, and then Then, the electromagnetic valve 22 is opened.

  In this way, even when the liquid refrigerant is trapped in the evaporator 24 and the refrigerant circulation flow rate is reduced, the high-pressure side pressure rises and the high-pressure side pressure exceeds the high-pressure cut control threshold. Stops the compressor 11 and stops refrigerant circulation in the refrigeration cycle.

  According to the above-described operation control, the electromagnetic valve 22 of the second decompression means 23A is opened after the outside air introduction mode is switched to the inside air introduction mode to reduce the cooling load of the evaporator 14 and reduce the refrigerant circulation flow rate. Generation of sound can be more reliably suppressed.

  In the above description, when the pressure threshold illustrated in FIG. 12 is used as a determination value, and it is determined that the high pressure side pressure of the refrigeration cycle is equal to or higher than this threshold, the discharge capacity of the compressor 11 is reduced. The electromagnetic valve 22 is opened and the liquid refrigerant is retained in the evaporator 24. However, the electromagnetic valve 22 is opened and the liquid refrigerant is retained in the evaporator 24 without reducing the discharge capacity of the compressor 11. You may suppress a raise.

  That is, based on the threshold value of the high pressure side pressure illustrated in FIGS. 11, 12, and 13, as illustrated in FIG. 10, the forced indoor air circulation mode is set and the rear solenoid valve 22 is opened as the high pressure side pressure increases. The liquid refrigerant may be retained in all the evaporators 24 and the compressor 11 may be stopped sequentially.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In each of the above-described embodiments, the refrigerant pressure detected by the pressure sensor 16 is equal to or higher than the predetermined pressure during the single operation of only the front indoor unit 30 in which the electromagnetic valve 22 is closed and the blower 45 is stopped, and the pressure on the high pressure side is abnormal. In the case where it is determined, the refrigerant discharge capacity of the compressor 11 is reduced as compared with that during normal control, and the electromagnetic valve 22 is opened after a predetermined time has elapsed.

  Although not described in the above embodiments, the control operation may be performed only when background noise other than the refrigerant passing sound is equal to or higher than a predetermined level. That is, it may not be performed when the background noise level is low.

  For example, when the blower amount of the blower 35 of the front indoor unit 30 is less than a predetermined amount, the execution of step 110 shown in FIG. 2 may be prohibited. According to this, when the air blowing amount of the blower 35 is a predetermined amount or more and the sound of blowing air is relatively large, the electromagnetic valve 22 can be opened by executing Step 110. Therefore, even if the refrigerant passing sound is generated when the electromagnetic valve 22 is opened, it is difficult for the user to hear the refrigerant passing sound due to the relatively large blowing sound, and the user can be prevented from feeling uncomfortable due to the refrigerant passing sound. .

  Further, for example, when the speed of the vehicle is less than a predetermined speed, the execution of step 110 may be prohibited. According to this, when the traveling speed of the vehicle is not less than the predetermined speed and the traveling noise is relatively loud, the electromagnetic valve 22 can be opened by executing step 110. Therefore, even if the refrigerant passing sound is generated when the solenoid valve 22 is opened, it is difficult for the user to hear the refrigerant passing sound due to the relatively loud running sound, and the user can be prevented from feeling uncomfortable due to the refrigerant passing sound. .

  Further, when it is determined that the refrigerant pressure detected by the pressure sensor 16 during single operation is equal to or higher than a predetermined pressure and the pressure on the high pressure side is abnormal, the solenoid valve 22 is opened while the refrigerant discharge capacity of the compressor 11 is normally controlled. The operation may be performed only when background noise other than the refrigerant passing sound is equal to or higher than a predetermined level. This also makes it difficult for the user to hear the refrigerant passing sound due to background noise and prevents the user from feeling uncomfortable due to the refrigerant passing sound.

  Further, only the front indoor unit 30 that does not circulate the external fluid to the rear evaporator 24 at the time of starting the single operation as described in the second and third embodiments or switching from the dual operation to the single operation, etc. Even when the electromagnetic valve 22 is opened and the liquid refrigerant is supplied to the evaporator 24 during the single operation, the electromagnetic valve 22 may be opened only when background noise other than the refrigerant passing sound becomes a predetermined level or higher.

  Further, in each of the above embodiments, as shown in FIG. 2, after the solenoid valve 22 is opened and the liquid refrigerant is supplied to the evaporator 24 during the single operation, the compressor 11 is returned to the normal control, and then the solenoid valve 22. Was closed. However, the order of returning the compressor 11 to normal control and returning the electromagnetic valve 22 to the closed state is not limited to this. The return to the normal control of the compressor 11 may be performed simultaneously with the closing of the electromagnetic valve 22, or the return to the normal control of the compressor 11 may be performed after the solenoid valve 22 is closed.

  In each of the above embodiments, the first pressure reducing means is the mechanical expansion valve 13 and the second pressure reducing means 23A is the electromagnetic valve 22 and the mechanical expansion valve 23. However, the present invention is not limited to this. is not. For example, the first pressure reducing means may be an electric (electric) expansion valve. Further, for example, the second pressure reducing means may be an electric (electric) expansion valve that can form a fully closed state.

  Further, in each of the above embodiments, when the control device 100 normally controls the compressor 11, the outer surface temperature TE of the evaporator 14, which is a related physical quantity of the heat absorption capability of the evaporator 14, is the evaporator 14 having the endothermic target value. The refrigerant discharge capacity of the compressor 11 was adjusted so as to coincide with the target temperature TEO of the compressor 11 (as close as possible).

  For normal control of the compressor 11, the evaporator temperature TE, which is the evaporator temperature, is used as the related physical quantity of the heat absorption capability of the evaporator 14, and the target evaporator temperature TEO is used as the endothermic target value. However, the present invention is not limited to this. Absent. Other related physical quantities of the endothermic capacity of the evaporator and the corresponding endothermic target value may be used, or the endothermic capacity of the evaporator (eg, product of enthalpy change amount and refrigerant flow rate) and the corresponding endothermic target value may be used. Also good.

  Further, in each of the above embodiments, the evaporator 14 that is the first evaporator is a heat exchanger that cools the air blown into the front seat space in the vehicle interior, and the evaporator 24 that is the second evaporator is the interior of the vehicle interior. Of these, the heat exchanger cools the air blown into the rear seat space, but is not limited thereto. For example, the first evaporator and the second evaporator may be reversed. Further, for example, the first evaporator may be a heat exchanger that cools the air blown into the cargo space of the vehicle, and the second evaporator may be a heat exchanger that cools the air blown into the passenger boarding space of the vehicle. Absent.

  Moreover, in each said embodiment, although the refrigerating-cycle apparatus 10 was equipped with two evaporators, the evaporator 14 and the evaporator 24, in parallel in a cycle, three or more evaporators may be sufficient. Absent.

  Moreover, although each said embodiment demonstrated the case where the refrigeration cycle apparatus 10 to which this invention was applied was used for the vehicle air conditioner 1, it is not limited to this. For example, even if the present invention is applied to a refrigeration cycle apparatus for a stationary air conditioner or a refrigeration cycle apparatus other than for air conditioning, it is extremely effective.

DESCRIPTION OF SYMBOLS 1 Vehicle air conditioner 10 Refrigeration cycle apparatus 11 Compressor 12 Radiator 13 Expansion valve (first decompression means)
14 Evaporator (first evaporator)
16 Pressure sensor (pressure detection means)
22 Solenoid valve (part of second decompression means)
23 Expansion valve (part of second decompression means)
23A Second decompression means 24 Evaporator (second evaporator)
34 Inside / outside air switching damper (inside / outside air switching means)
35 Blower (Blower means)
100 Control device (control means)

Claims (8)

A compressor (11) for compressing and discharging the refrigerant;
A radiator (12) for releasing heat from the refrigerant discharged from the compressor (11);
First decompression means (13) for decompressing and expanding the refrigerant flowing out of the radiator (12);
A first evaporator (14) for evaporating the refrigerant decompressed by the first decompression means (13) by absorbing heat from the first external fluid;
A decompression mode that is provided in parallel with the first decompression means (13) and decompresses and expands the refrigerant flowing out of the radiator (12); and a distribution prohibiting mode that prohibits circulation of the refrigerant flowing out of the radiator (12). A second decompression means (23A) capable of switching between;
An evaporation mode that is provided in parallel with the first evaporator (14) and evaporates the refrigerant depressurized by the second depressurization means (23A) according to the presence or absence of circulation of a second external fluid that exchanges heat with the refrigerant; A second evaporator (24) that is switched between an evaporation stop mode for stopping evaporation of the refrigerant decompressed by the decompression means (23A);
Pressure detection means (16) for detecting the pressure of the refrigerant before being discharged from the compressor (11) and reduced in pressure by the first pressure reduction means (13);
Control of mode switching of the second decompression means (23A) and the compression so that the endothermic capacity of the first evaporator (14) or the value of the associated physical quantity (TE) coincides with the endothermic target value (TEO). Control means (100) for controlling the refrigerant discharge capacity of the machine (11),
The control means (100)
The pressure detected by the pressure detection means (16) when the second decompression means (23A) is in the flow prohibition mode and the second evaporator (24) is in the evaporation stop mode is predetermined. If it exceeds the pressure,
Regardless of the relationship between the endothermic capacity or the value of the related physical quantity (TE) and the endothermic target value (TEO), the compressor is more than when the pressure detecting means (16) detects a pressure equal to or higher than the predetermined pressure. A first step (108) of reducing the refrigerant discharge capacity of (11);
A step performed after said first step (108), and the second step of the second pressure reducing means (23A) and the pressure decrease mode (110),
It is a step performed after the second step, and the refrigerant discharge capacity of the compressor (11) is controlled so that the endothermic capacity or the related physical quantity value (TE) coincides with the endothermic target value (TEO). In addition, the third step (112, 114) for setting the second decompression means (23A) in the circulation prohibition mode is sequentially executed.   In the third step (112, 114), the control means (100) is configured so that the endothermic capacity or the related physical quantity value (TE) matches the endothermic target value (TEO). 2. The refrigeration cycle apparatus according to claim 1, wherein the refrigerant discharge capacity is controlled, and then the second decompression unit (23 </ b> A) is set to the flow prohibition mode.   When starting the compressor (11) when the second evaporator (24) is in the evaporation stop mode, the control means (100) causes the second decompression means (23A) to The refrigeration cycle apparatus according to claim 1 or 2, wherein the compressor (11) is started as a decompression mode, and then the second decompression means (23A) is set to the circulation prohibition mode.   When the second evaporator (24) is switched from the evaporation mode to the evaporation stop mode, the control means (100) is provided with the second decompression means (23A) after the switch to the evaporation stop mode. The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the decompression mode is continued, and then the second decompression means (23A) is set to the flow prohibition mode. .   When the second evaporator (24) is in the decompression mode when the second evaporator (24) is in the evaporation stop mode, the control device (100) The second depressurization means (23A) is controlled so as to intermittently form the depressurization mode by alternately repeating the distribution prohibition mode. The refrigeration cycle apparatus described in 1. The first external fluid is air blown into a room,
Switching between an inside air introduction mode for supplying the first external fluid from the room to the first evaporator (14) and an outside air introduction mode for supplying the first outside fluid to the first evaporator (14) from the outside. Possible inside / outside air switching means (34),
The control means (100) sets the outside air introduction mode to the inside air when the second step (110) is executed when the inside / outside air switching means (34) is set to the outside air introduction mode. The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein the second decompression means (23A) is set to the decompression mode after switching to the introduction mode. The first evaporator (14) includes air blowing means (35) for blowing the first external fluid,
The said control means (100) prohibits execution of said 2nd step (110), when the ventilation volume of the said ventilation means (35) is less than predetermined amount. The refrigeration cycle apparatus according to any one of the above. A refrigeration cycle device (10) mounted on a vehicle,
The control means (100) prohibits execution of the second step (110) when the speed of the vehicle is less than a predetermined speed. The refrigeration cycle apparatus described.

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