JP2017137012A - Vehicular air conditioner, vehicle including the same and control method for vehicular air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular air conditioner having a high performance coefficient even when a thermal load is not high and capable of contributing to power saving in a refrigeration cycle including an inner heat exchanger, a vehicle including the same and a control method for the vehicular air conditioner.SOLUTION: A vehicular air conditioner 100 is mounted to a vehicle. The vehicular air conditioner includes: a refrigeration cycle 1a having a refrigerant circuit 50 that is formed by interconnecting by piping 61-66 a compressor 2, a condenser 3, an expansion device 4 and an evaporator 5 to circulate a refrigerant and an inner heat exchanger 10 for exchanging heat of a refrigerant between a first heat exchange section 11 in which the refrigerant guided from condenser 3 to the expansion device 4 flows and a second heat exchange section 12 in which the refrigerant guided from the evaporator 5 to the suction side of the compressor 2 flows; an outside air temperature sensor 41 for detecting an outside air temperature of the vehicle; a heat radiation amount adjustment device 7 for adjusting the heat radiation amount of the refrigerant of which heat is radiated by the condenser 3; and a processing device 150 for controlling the heat radiation amount adjustment device 7 on the basis of a value of the outside air temperature.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle air conditioner, a vehicle including the same, and a control method for the vehicle air conditioner, and particularly contributes to power saving in a vehicle air conditioner including an internal heat exchanger and a heat dissipation amount adjusting device for a condenser. Regarding technology.

  As a configuration for improving the cooling capacity and coefficient of performance (COP) of the refrigeration cycle, for example, an internal heat exchanger (a relatively high temperature refrigerant flowing out of the condenser and a relatively high temperature flowing out of the evaporator) A technique is known in which a device that exchanges heat with a low refrigerant) is arranged in a refrigeration cycle (see, for example, Patent Document 1). The coefficient of performance COP is shown as a value (Qe / L) obtained by dividing the heat absorption amount Qe in the evaporator by the power L of the compressor, and the larger the value, the better the efficiency.

  By arranging the internal heat exchanger in the refrigeration cycle, the entropy of the refrigerant flowing out of the condenser is reduced, the heat absorption amount Qe of the evaporator is increased, and the entropy of the refrigerant flowing out of the evaporator is increased to increase the power of the compressor. L increases. At this time, since the increase rate of Qe is usually larger than the increase rate of L, the coefficient of performance (COP = Qe / L) is increased and the efficiency is improved.

Japanese Patent Laid-Open No. 2008-122034

  However, even if an internal heat exchanger is arranged in the refrigeration cycle and the coefficient of performance COP is improved, when the heat load is not high (for example, when the outside air temperature is 10 ° C. or lower), the coefficient of performance is sufficiently improved. I couldn't. This is because the heat load (outside air temperature, etc.) is not high, heat exchange (heat radiation) in the condenser is promoted, the temperature of the high-pressure refrigerant flowing into the internal heat exchanger is lowered, and the evaporator changes from the evaporator to the internal heat exchanger. Heat cannot be sufficiently exchanged with the inflowing gas-liquid mixed state low-pressure refrigerant, and the refrigerant containing the liquid is sucked into the compressor (a phenomenon called so-called liquid compression occurs), or the ratio of the liquid-phase refrigerant is This is because the power L of the compressor increases as a result.

  Even when the heat load is not high, the air conditioner may be operated in a dehumidifying heating mode in which both the refrigeration cycle and the heating heat exchanger are operated in order to remove fogging of the vehicle window. . In other words, considering the usage of air conditioners throughout the year, it is strongly required to improve the coefficient of performance of the refrigeration cycle even when the heat load is not high.

  Accordingly, an object of the present invention is to provide a vehicle air conditioner having a high coefficient of performance and contributing to power saving in a refrigeration cycle having an internal heat exchanger, even when the heat load is not high, a vehicle equipped with the vehicle, and a vehicle It is providing the control method of an air conditioner.

  The vehicle air conditioner according to the present invention includes a refrigerant circuit for circulating a refrigerant by connecting a compressor, a condenser, an expansion device, and an evaporator with a pipe in the vehicle air conditioner mounted on the vehicle, and the condenser. Internal heat exchange of the refrigerant between the first heat exchange section through which the refrigerant guided to the expansion device flows and the second heat exchange section through which the refrigerant guided from the evaporator to the suction side of the compressor flows A refrigeration cycle having a heat exchanger, an outside air temperature sensor for detecting an outside air temperature of the vehicle, a heat release amount adjusting device for adjusting a heat release amount of the refrigerant radiated by the condenser, and a value of the outside air temperature. And a processing device for controlling the heat radiation amount adjusting device.

  In the vehicle air conditioner according to the present invention, the processing device includes the value of the outside air temperature, (a) the pressure of the refrigerant in the high-pressure line, (b) the traveling speed of the vehicle, (c) the room temperature of the vehicle, (D) at least one selected from (a) to (e) of the temperature of the evaporator or the temperature of the air that has passed through the evaporator, and (e) the amount of air blown from the blower fan to the evaporator It is preferable to control the heat radiation amount adjusting device based on the above. It can prevent more reliably that the refrigerant | coolant containing a liquid is suck | inhaled by the compressor.

  In the vehicle air conditioner according to the present invention, the heat radiation amount adjusting device is disposed in front of the refrigeration cycle, and has a grille opening that can adjust an opening degree between a minimum opening degree and a maximum opening degree. It is preferable that the processing apparatus controls an opening degree of the grill opening. The amount of heat radiation in the condenser can be adjusted appropriately. As a result, even when the heat load is not high, the compressor can be prevented from sucking the liquid refrigerant, and the coefficient of performance can be further increased.

  In the vehicle air conditioner according to the present invention, the heat radiation amount adjusting device includes a cooling fan that generates a flow of air that cools the condenser, and the processing device controls an air blowing amount of the cooling fan. preferable. The amount of heat radiation in the condenser can be adjusted appropriately. As a result, even when the heat load is not high, the compressor can be prevented from sucking the liquid refrigerant, and the coefficient of performance can be further increased.

  In the vehicle air conditioner according to the present invention, it is preferable that the processing device gives priority to the control for reducing the opening degree of the grill opening rather than the control for reducing the air flow rate of the cooling fan. The amount of heat released from the condenser can be reduced more efficiently.

  In the vehicle air conditioner according to the present invention, the heat radiation amount adjusting device branches from the refrigerant circuit between the compressor and the condenser, and the refrigerant between the condenser and the internal heat exchanger. A bypass passage connected to the circuit; and a refrigerant distributor that changes a ratio of the refrigerant flowing through the bypass passage out of the refrigerant flowing out of the compressor, wherein the refrigeration cycle is a gaseous refrigerant It is preferable that a liquid tank or an accumulator that separates the liquid refrigerant from the liquid refrigerant is provided, and the processing device controls the refrigerant distributor. The amount of heat radiation in the condenser can be adjusted appropriately. As a result, even when the heat load is not high, the compressor can be prevented from sucking the liquid refrigerant, and the coefficient of performance can be further increased.

  In the vehicle air conditioner according to the present invention, the compressor is preferably a fixed capacity type. If a fixed capacity compressor is used, the compressor may be intermittently operated to prevent the evaporator from freezing. Can be controlled.

  In the vehicle air conditioner according to the present invention, the processing device is preferably mounted on an air conditioning control unit or mounted on an engine control unit. The degree of design freedom can be further increased.

  The vehicle according to the present invention is equipped with the vehicle air conditioner according to the present invention.

  A control method for a vehicle air conditioner according to the present invention is a control method for a vehicle air conditioner according to the present invention, wherein the vehicle air conditioner includes an operation switch of the refrigeration cycle, and the processing device includes the operation Recognizing that the switch has been activated, comparing the outside air temperature with a predetermined temperature, and when determining that the outside air temperature is lower than the predetermined temperature, reducing the heat radiation amount in the condenser, To do.

  As described above, the present invention provides a vehicle air conditioner that has a high coefficient of performance and can contribute to power saving in a refrigeration cycle having an internal heat exchanger, even when the heat load is not high, a vehicle including the vehicle, and a vehicle It is possible to provide a method for controlling an air conditioner for a vehicle.

1 is a system diagram illustrating a first example of a vehicle air conditioner according to an embodiment. It is a system diagram which shows the 2nd example of the vehicle air conditioner which concerns on this embodiment. It is a graph which shows the relationship between the outside temperature in Example 1 and Comparative Example 1, and a coefficient of performance.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components. Various modifications may be made as long as the effects of the present invention are achieved.

  As shown in FIGS. 1 and 2, the vehicle air conditioners 100 and 200 according to the present embodiment are a compressor 2, a condenser 3, an expansion device 4, and an evaporator 5 in a vehicle air conditioner mounted on a vehicle. To the suction side of the compressor 2 from the first heat exchanging unit 11 and the evaporator 5 through which the refrigerant guided from the condenser 3 to the expansion device 4 flows. Refrigeration cycles 1a and 1b having an internal heat exchanger 10 that performs heat exchange of the refrigerant with the second heat exchange unit 12 through which the refrigerant to be guided flows, an outside air temperature sensor 41 that detects an outside air temperature of the vehicle, A heat release amount adjustment device 7 that adjusts the heat release amount of the refrigerant radiated by the condenser 3 and a processing device 150 that controls the heat release amount adjustment device 7 based on the value of the outside air temperature are provided.

  The refrigerant circuit 50 is a closed circuit in which the compressor 2, the condenser 3, the expansion device 4, and the evaporator 5 are connected by pipes 61 to 66, and the refrigerant circulates inside. The refrigerant is, for example, a fluorocarbon material such as R134a, HFO-1234yf, or carbon dioxide. The refrigerant circuit 50 separates the gaseous refrigerant and the liquid refrigerant inside the condenser 3 or between the condenser 3 and the internal heat exchanger 10 when the refrigerant circulating inside is a fluorocarbon material. In addition, a liquid tank (not shown) for storing a part of the refrigerant is provided. The refrigerant circuit 50 includes an accumulator (not shown) that stores a part of the refrigerant between the evaporator 5 and the compressor 2 when the refrigerant circulating inside is carbon dioxide.

  The compressor 2 receives a driving force from an engine (not shown) or a driving force of a motor (not shown) driven by electric power, compresses the refrigerant in a vaporized state at low temperature and low pressure, Use high-pressure vaporized refrigerant.

  The compressor 2 is, for example, a fixed capacity type compressor or a variable capacity type compressor. In the present embodiment, the compressor 2 is preferably a fixed capacity type.

  The condenser 3 is generally disposed in front of the radiator in the engine room at the front end (front) of the vehicle. The condenser 3 is a heat exchanger, and the high-temperature and high-pressure vaporized refrigerant discharged from the compressor 2 is introduced from the grill opening 21 by either running the vehicle or operating the cooling fan 30 or both. The vehicle is cooled by outside air in front of the vehicle, and is converted into a high-temperature and high-pressure liquefied refrigerant.

  The expansion device 4 depressurizes and expands the refrigerant condensed in the condenser 3 to produce a low-temperature and low-pressure mist refrigerant (gas-liquid mixed refrigerant) and adjusts the flow rate of the refrigerant. . The expansion device 4 is, for example, a temperature-sensitive expansion valve or an electronically controlled expansion valve.

  The evaporator 5 is a heat exchanger, vaporizes the refrigerant that has become a gas-liquid mixture in the expansion device 4, and cools and dehumidifies the blown air that passes through the evaporator 5 with the heat of evaporation at that time.

  The internal heat exchanger 10 is disposed on the refrigerant circuit 50. The internal heat exchanger 10 includes a first heat exchange unit 11 through which the refrigerant guided from the condenser 3 to the expansion device 4 flows, and a second heat exchange unit through which the refrigerant guided from the evaporator 5 to the suction side of the compressor 2 flows. 12, and performs heat exchange between a relatively high temperature refrigerant flowing through the first heat exchange unit 11 and a relatively low temperature refrigerant flowing through the second heat exchange unit 12.

  The pipe 61 connects the outlet of the compressor 2 and the inlet of the condenser 3 directly or indirectly. The pipe 62 connects the outlet of the condenser 3 and the inlet of the first heat exchange unit 11 directly or indirectly. The pipe 63 connects the outlet of the first heat exchange unit 11 and the inlet of the expansion device 4 directly or indirectly. The pipe 64 connects the outlet of the expansion device 4 and the inlet of the evaporator 5 directly or indirectly. The pipe 65 connects the outlet of the evaporator 5 and the inlet of the second heat exchange unit 12 directly or indirectly. The pipe 66 connects the outlet of the second heat exchange unit 12 and the inlet of the compressor 2 directly or indirectly.

  The outside air temperature sensor 41 is a device that detects the outside air temperature (vehicle ambient temperature). The approximate superheat degree of the refrigerant sucked by the compressor 2 can be estimated from the value of the outside air temperature, and the outside air temperature sensor 41 can also be called a superheat degree estimation device.

  The heat release amount adjusting device 7 is, for example, a device that cools the condenser 3 or a device that changes the flow rate of the refrigerant flowing through the condenser 3. A device for cooling the condenser 3 is, for example, a vehicle grill device 20 or a cooling fan 30 as shown in FIGS. 1 and 2. The device for changing the flow rate of the refrigerant flowing through the condenser 3 is a mechanism including a bypass passage 70 and a refrigerant distribution device 71 as shown in FIG.

  The vehicle grill device 20 is disposed in front of the refrigeration cycles 1a and 1b, and includes a grille opening 21, a louver 22 and a motor 23 whose opening degree can be adjusted between a minimum opening degree and a maximum opening degree. Have. The grill opening 21 is provided in the front part of the vehicle such as a front grille, and is an inlet for introducing outside air in front of the vehicle into the engine room. The outside air introduced into the engine room from the grill opening 21 passes through the condenser 3. As a result, the high-temperature and high-pressure refrigerant in the condenser 3 is cooled. The louver 22 is an open / close shutter that changes the opening area of the grill opening 21. The motor 23 is a drive device that rotates each slat of the louver 22.

  When the direction of the louver 22 is closest to the horizontal direction in the rotatable range of the louver 22, the grille opening 21 has a maximum opening area. On the other hand, when the direction of the louver 22 is closest to the vertical direction in the rotatable range of the louver 22, the grille opening 21 has a minimum opening area. The opening degree of the vehicle grill device 20 is a value indicating the opening area as a percentage, where the minimum opening area of the grill opening 21 is 0% and the maximum opening area of the grill opening 21 is 100%.

  The vehicle grill device 20 adjusts the opening degree to a predetermined opening degree between the minimum opening degree (0%) and the maximum opening degree (100%) by driving the motor 23. When the opening degree becomes the minimum opening degree, the grille opening 21 may be in a fully closed state or may be in a slightly open state.

  The cooling fan 30 has an impeller 31 and a motor 32. In the cooling fan 30, the impeller 31 is rotated by the motor 32 to generate an air flow for cooling the condenser 3. The amount of air introduced into the condenser 3 changes according to the rotational speed of the motor 32. The cooling fan 30 may be a fan dedicated to the condenser 3, or may be a fan that also serves to cool a radiator (not shown) disposed close to the leeward side of the condenser 3. The cooling fan 30 may be disposed on the front side of the vehicle with respect to the condenser 3 or may be disposed on the rear side of the vehicle. Further, the number of cooling fans 30 is not particularly limited, and may be one or two or more.

  As shown in FIG. 2, the bypass passage 70 branches from the refrigerant circuit 50 between the compressor 2 and the condenser 3 and is connected to the refrigerant circuit 50 between the condenser 3 and the internal heat exchanger 10. It is a passage and forms a refrigerant path in which the refrigerant circulates around the condenser 3.

  The refrigerant distribution device 71 is a device that changes the ratio of the refrigerant flowing out of the compressor 2 and flowing through the bypass passage 70. For example, the refrigerant distribution device 71 is a three-way valve (shown in FIG. 2) or a two-way valve (not shown). (Illustrated). When the refrigerant distribution device 71 is a three-way valve, the three-way valve is preferably arranged at a branch portion P1 between the refrigerant circuit 50 and the bypass passage 70. When the refrigerant distributor 71 is a two-way valve, the two-way valve is preferably disposed in the bypass passage 70. Further, in addition to the arrangement in the bypass passage 70, the two-way valve may be further arranged in the pipe 61 on the condenser 3 side than the branch portion P <b> 1 between the refrigerant circuit 50 and the bypass passage 70.

  When the bypass passage 70 is provided, the refrigeration cycle 1b preferably has the liquid tank 6 or an accumulator (not shown). It is preferable that the liquid tank 6 is disposed between the joining portion P <b> 2 between the refrigerant circuit 50 and the bypass passage 70 and the expansion device 4. For example, as shown in FIG. 2, the liquid tank 6 is preferably arranged in the pipe 62 on the internal heat exchanger 10 side with respect to the junction P <b> 2 between the refrigerant circuit 50 and the bypass passage 70. The gaseous refrigerant discharged from the compressor 2 passes through the bypass passage 70, joins with the liquid refrigerant flowing through the condenser 3, and flows into the liquid tank 6. In the liquid tank 6, the gaseous refrigerant is separated, and only the liquid refrigerant is sent to the first heat exchange unit 11. The refrigerant that has flowed out of the first heat exchange unit 11 passes through the second heat exchange unit 12 through the expansion device 4 and the evaporator 5, and is again sucked into the compressor 2. The place where the liquid tank 6 is disposed is not limited to the pipe 62. For example, the liquid tank 6 may be disposed in the pipe 63 between the first heat exchange unit 11 and the expansion device 4. When the liquid tank 6 is disposed in the pipe 63, the gas-liquid mixed refrigerant passes through the first heat exchange unit 11. Since the refrigerant in the gas-liquid mixed state has a specific volume larger than that of the liquid refrigerant, it is devised to reduce the passage resistance of the first heat exchange unit 11 such as increasing the flow path area of the first heat exchange unit 11. It is preferable. The accumulator (not shown) is arranged in a pipe 65 between the evaporator 5 and the second heat exchange unit 12 or a pipe 66 between the second heat exchange unit 12 and the compressor 2.

  The vehicle air conditioners 100 and 200 according to the present embodiment include (1) the vehicle grill device 20, (2) the cooling fan 30, and (3) the bypass passage 70 and the refrigerant distributor 71 as the heat release amount adjusting device 7. It is preferable to have at least one selected from the mechanisms (1) to (3). The present invention is not limited to the combination of the heat radiation amount adjusting device 7, and as an example, in FIG. 1, the heat radiation amount adjusting device 7 is (1) a vehicle grill device 20 and (2) a cooling fan 30, FIG. Then, although the heat radiation amount adjusting device 7 showed the form which is a mechanism provided with (1) the grill device 20 for vehicles, (2) the cooling fan 30, and (3) the bypass passage 70 and the refrigerant | coolant distribution apparatus 71, this invention is shown. It is not limited to these combinations.

  The processing device 150 controls the heat release amount adjustment device 7 based on the value of the outside air temperature so that the superheat degree of the refrigerant sucked by the compressor 2 becomes larger than a predetermined superheat degree. The degree of superheat of the refrigerant sucked by the compressor 2 can be roughly estimated from the value of the outside air temperature. Here, the greater the degree of superheat of the refrigerant sucked by the compressor 2, the lower the possibility that the refrigerant containing the liquid or the liquid phase refrigerant is sucked into the compressor 2. On the other hand, when the degree of superheat is smaller than a predetermined value, a refrigerant containing a liquid or a liquid phase refrigerant may be sucked into the compressor 2. Therefore, the processing device 150 sets the control amount of the heat radiation amount adjusting device 7 so as to decrease the heat radiation amount in the condenser 3 when the degree of superheat is smaller than a predetermined value. As a result, the refrigerant containing the liquid can be prevented from being sucked into the compressor 2.

  The processing device 150 controls the heat radiation amount adjusting device 7 based on a profile in which the control amount of the heat radiation amount adjusting device 7 with respect to the value of the outside air temperature is set in advance, or based on the value of the outside air temperature, the compressor 2. May estimate the superheat degree of the refrigerant sucked and control the heat radiation amount adjusting device 7 based on the estimated superheat degree.

  In addition, the processing device 150 includes the value of the outside air temperature, (a) the refrigerant pressure in the high-pressure line, (b) the traveling speed of the vehicle, (c) the room temperature of the vehicle, (d) the temperature of the evaporator 5 or the evaporator. The heat radiation amount adjusting device 7 is controlled based on the temperature of the air that has passed through 5 and (e) at least one selected from (a) to (e) of the amount of air blown from the blower fan to the evaporator 5. It is preferable to do. By adding at least one of (a) to (e) to the value of the outside air temperature, the superheat degree of the refrigerant sucked by the compressor 2 can be estimated with higher accuracy, and the refrigerant containing the liquid is compressed by the compressor 2. Inhalation can be more reliably prevented.

  (A) The pressure of the refrigerant in the high-pressure line is a detection value of the pressure sensor 42 having measurement points in the high-pressure lines of the refrigeration cycles 1a and 1b, and has a high correlation with the refrigerant discharge amount by the compressor 2. The pressure sensor 42 preferably has a measurement point in the pipe 62 on the downstream side of the condenser 3. The high pressure line is a line from the compressor 2 to the expansion device 4.

  (B) The traveling speed of the vehicle is a value detected by the vehicle speed sensor 43.

  (C) The vehicle interior temperature is a value detected by the room temperature sensor 44.

  (D) The temperature of the evaporator 5 or the temperature of the air that has passed through the evaporator 5 is a detection value of the thermosensor 45 and has a correlation with the refrigerant discharge amount by the compressor 2. When the thermo sensor 45 detects the temperature of the evaporator 5, the measurement point of the thermo sensor 45 is attached to, for example, a fin at a part where the temperature is lowest in the evaporator 5. When the thermosensor 45 detects the temperature of the air that has passed through the evaporator 5, the measurement point of the thermosensor 45 is conventionally known, for example, in a space downstream of the portion of the evaporator 5 where the temperature is lowest. It is attached with the configuration.

  (E) The amount of air blown from the blower fan to the evaporator 5 is, for example, a value calculated by multiplying a drive voltage of a blower motor that drives a blower fan (not shown) by a predetermined coefficient.

  When the control amount of the heat release amount adjustment device 7 is determined by adding at least one of (a) to (e) to the value of the outside air temperature, the heat release amount adjustment device 7 determined based only on the outside air temperature. It is preferable to correct the control amount (hereinafter referred to as a basic control amount) according to each value of (a) to (e). For example, when the pressure value in (a) is lower than a predetermined value, it can be said that heat dissipation in the condenser 3 is excessively promoted, and therefore it is estimated that the degree of superheat of the refrigerant immediately before the compressor 2 is reduced. The For this reason, if the heat radiation amount adjusting device 7 is continuously controlled with the basic control amount maintained, the proportion of the liquid refrigerant contained in the refrigerant sucked into the compressor 2 increases, and there is a concern that the refrigeration efficiency is lowered. Therefore, the control amount of the heat radiation amount adjusting device 7 is corrected in a direction to decrease the heat radiation amount in the condenser 3 with respect to the basic control amount so as to suppress excessive heat radiation in the condenser 3. When the speed value of (b) is faster than the predetermined value, when the temperature value of (c) is lower than the predetermined value, when the temperature value of (d) is lower than the predetermined value, or in (e) Even when the value of the blown air amount is less than the predetermined value, it is estimated that the degree of superheat of the refrigerant immediately before the compressor 2 becomes small, as in the case where the pressure value of (a) is lower than the predetermined value. Since there is a concern about an increase in the ratio of the liquid refrigerant contained in the refrigerant sucked into the compressor, the amount of heat radiation in the condenser 3 is reduced with respect to the control amount of the heat radiation amount adjusting device 7 with respect to the basic control amount. Correct in the direction.

  The processing device 150 is preferably mounted on the air conditioning control unit or mounted on the engine control unit. It is possible to flexibly cope with various factors such as vehicle design philosophy, memory capacity or cost. Further, among the processing devices 150, the device that controls the vehicle grill device 20, the device that controls the cooling fan 30, and the device that controls the refrigerant distribution device 71 may be one device or may be separate devices. Good.

  Next, the control method of the vehicle air conditioner according to the present embodiment will be described.

  In the control method for a vehicle air conditioner according to the present embodiment, the vehicle air conditioners 100 and 200 include operation switches (not shown) of the refrigeration cycles 1a and 1b, and the processing device 150 indicates that the operation switch is operated. Recognize (step 1), compare the outside air temperature with a predetermined temperature (step 2), and when it is determined that the outside air temperature is lower than the predetermined temperature, the heat release amount in the condenser 3 is decreased (step 3).

  The operation switches of the refrigeration cycles 1a and 1b are switches for starting the compressor 2, for example, air conditioner switches. In step 1, the operation switch is operated, for example, when the passenger presses the air conditioner switch. When the compressor 2 is a fixed capacity compressor, the intermittent operation of the compressor 2 may be automatically performed in order to prevent the evaporator 5 from freezing. In the intermittent operation, the determination result when the compressor 2 is driven is applied mutatis mutandis during the time period when the compressor 2 is not driven. It is possible to prevent the heat radiation amount control device 7 from being excessively controlled every time the intermittent operation is performed, and to extend the useful life of the heat radiation amount control device.

  In step 2, the predetermined temperature is preferably 5 to 15 ° C, and more preferably 8 to 12 ° C, for example.

  When it is determined in step 2 that the outside air temperature is lower than the predetermined temperature, step 3 is executed. In step 3, the processing device 150 controls the heat radiation amount adjusting device 7 so that the heat radiation amount in the condenser 3 decreases. As a result, it is possible to prevent the temperature of the high-pressure refrigerant flowing into the first heat exchange unit 11 from becoming too low. As a result, the low-pressure refrigerant flowing through the second heat exchange unit 12 is appropriately heated by heat exchange with the high-pressure refrigerant flowing through the first heat exchange unit 11, and the degree of superheat of the refrigerant immediately before the compressor 2 Can be increased. As a result, the refrigerant containing the liquid can be prevented from being sucked into the compressor 2.

  In step 3, the basic control amount of the heat release amount adjusting device 7 determined based only on the outside air temperature is calculated by: (a) the refrigerant pressure in the high pressure line, (b) the vehicle traveling speed, (c) the vehicle indoor temperature, (D) Considering at least one selected from (a) to (e) of the temperature of the evaporator or the temperature of the air that has passed through the evaporator and (e) the amount of air blown from the blower fan to the evaporator Further, step 4 for correcting may be included. When step 4 is executed, the processing device 150 controls the heat radiation amount adjusting device 7 based on the corrected control amount.

  When the heat radiation amount adjusting device 7 is the vehicle grill device 20, the processing device 150 controls the opening degree of the grill opening 21. In step 3, the processing device 150 decreases the opening degree. More preferably, the opening degree is the minimum opening degree. The smaller the opening degree, the smaller the amount of air that passes through the condenser 3, so that the heat radiation amount in the condenser 3 decreases.

  When the heat radiation amount adjusting device 7 is the cooling fan 30, the processing device 150 controls the amount of air blown from the cooling fan 30. In step 3, the processing device 150 reduces the air flow rate of the cooling fan 30. More preferably, the air blowing amount of the cooling fan 30 is set as the minimum air blowing amount. Further, when the cooling fan 30 also serves to cool the radiator, it is preferable that the control of the air flow rate of the cooling fan 30 is performed with priority given to the cooling of the radiator. Here, the amount of air blown by the cooling fan 30 is the amount of air blown by the cooling fan when the number of cooling fans 30 is one, and is formed by each cooling fan when the number of cooling fans 30 is two or more. This is the total air flow. Since the amount of air passing through the condenser 3 decreases as the amount of blown air decreases, the amount of heat released from the condenser 3 decreases. The minimum air flow rate is 0 when the cooling fan 30 is dedicated to the condenser or when the cooling fan 30 is also used for cooling the radiator and cooling of the radiator is not necessary. When the cooling fan 30 also serves as cooling of the radiator and the cooling of the radiator is necessary, the minimum blowing amount is the blowing amount necessary for cooling the radiator.

  When the heat radiation amount adjusting device 7 is a mechanism including the bypass passage 70 and the refrigerant distribution device 71, the processing device 150 controls the refrigerant distribution device 71. In step 3, the processing device 150 increases the ratio of the refrigerant flowing through the bypass passage 70. As the ratio of the refrigerant flowing through the bypass passage 70 increases, the flow rate of the refrigerant flowing through the condenser 3 decreases, and the heat radiation amount in the condenser 3 decreases. The ratio of the refrigerant flowing through the bypass passage 70 is not particularly limited.

  Any of the mechanisms including the vehicle grill device 20, the cooling fan 30, the bypass passage 70, and the refrigerant distribution device 71 can appropriately adjust the heat radiation amount in the condenser 3. As a result, even when the heat load is not high, the compressor 2 can be prevented from sucking the liquid refrigerant and the coefficient of performance can be further increased.

  In step 3, when the vehicle air conditioners 100 and 200 include the vehicle grill device 20 and the cooling fan 30 as the heat radiation amount adjusting device 7, the processing device 150 performs the grill rather than the control for reducing the air flow rate of the cooling fan 30. It is preferable to prioritize control that reduces the degree of opening of the opening 21. Decreasing or closing the opening degree of the grill opening 21 has a larger effect of reducing the heat radiation amount in the condenser 3 than reducing the air blowing amount of the cooling fan. For this reason, the heat dissipation in the condenser 3 can be reduced more efficiently.

  Further, when the vehicle air conditioners 100 and 200 include the vehicle grill device 20 and the cooling fan 30 as the heat radiation amount adjusting device 7, the processing device 150 controls the opening degree of the grill opening 21 and the cooling fan 30. You may perform simultaneously with the control which reduces ventilation volume. The amount of heat released from the condenser 3 can be reduced more efficiently.

  When it is determined in step 2 that the outside air temperature is equal to or higher than the predetermined temperature, the processing device 150 keeps the heat dissipation amount in the condenser 3 as it is at the time of determination or increases the heat dissipation amount in the condenser 3. May be.

  The vehicle according to the present embodiment is equipped with the vehicle air conditioners 100 and 200 according to the present embodiment. As described above, the vehicle air conditioner 100 according to the present embodiment can appropriately adjust the amount of heat released from the condenser 3 to prevent the refrigerant containing liquid from being sucked into the compressor 2. As a result, the vehicle according to the present embodiment has a high coefficient of performance of the refrigeration cycle even when the heat load is small, and can contribute to power saving.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to this Example at all.

Example 1
In the refrigeration cycle 1a shown in FIG. 1, the processing device 150 controls the opening degree of the vehicular grill device 20 based on the value of the outside air temperature. Specifically, when the outside air temperature exceeds 12 ° C., the opening degree of the vehicle grill device 20 is set as the maximum opening degree. When the outside air temperature was 3 ° C. or lower, the opening degree of the vehicle grill device 20 was changed to the minimum opening degree. In addition, the ventilation volume of the cooling fan 30 was 30% of the maximum ventilation volume at any outside air temperature.

(Comparative Example 1)
In the refrigeration cycle 1a shown in FIG. 1, regardless of the value of the outside air temperature, the opening degree of the vehicle grill device 20 is kept at the maximum opening degree, and the blowing amount of the cooling fan 30 is set to 30% of the maximum blowing amount.

(Example 2)
In the refrigeration cycle 1b shown in FIG. 2, the processing device 150 controls the refrigerant distributor 71 based on the value of the outside air temperature. Specifically, when the outside air temperature exceeded 12 ° C., the entire amount of the refrigerant was passed through the condenser 3, and no refrigerant was passed through the bypass passage 70. Further, when the outside air temperature is 3 ° C. or lower, the flow rate of the refrigerant flowing through the bypass passage 70 with respect to the total flow rate (unit: kg / s) of the refrigerant flowing through the pipe 61 between the compressor 2 and the condenser 3 ( The ratio of unit: kg / s was changed to 30%.

(Comparative Example 2)
In the refrigeration cycle 1 b shown in FIG. 2, the processing device 150 allows the entire amount of the refrigerant to flow to the condenser 3 regardless of the value of the outside air temperature, and does not flow the refrigerant through the bypass passage 70.

  FIG. 3 is a graph showing the relationship between the outside air temperature and the coefficient of performance in Example 1 and Comparative Example 1. In FIG. 3, the solid line 901 indicates Example 1 and the dotted line 902 indicates Comparative Example 1. As shown in FIG. 3, when the outside air temperature is not high (for example, when the outside air temperature is 12 ° C. or lower), Example 1 (solid line 901) suppresses the drop in COP more than Comparative Example 1 (dotted line 902). We were able to. Also in Example 2, the same effect as Example 1 was confirmed.

  Heretofore, the decrease in the coefficient of performance (COP) is such that when the heat load is not high, the ratio of the liquid phase contained in the refrigerant sucked into the compressor 2 increases, and the power L of the compressor 2 increases. It has been explained on the premise of doing. However, a decrease in the coefficient of performance occurs even when the heat load is extremely high. This is because the heat load (outside air temperature, etc.) is high and heat exchange (heat radiation) in the condenser 3 is insufficient, the temperature of the high-pressure refrigerant flowing into the internal heat exchanger 10 becomes too high, and the internal heat from the evaporator 5 This is because heat exchange with the low-temperature and low-pressure refrigerant flowing into the exchanger 10 is excessively promoted, and refrigerant having a large superheat degree is sucked into the compressor 2 and, as a result, the power L of the compressor 2 is excessively increased. Thus, since the coefficient of performance of the refrigerant circuit 50 having the internal heat exchanger 10 decreases not only when the heat load is too low but also when it is too high, the highest efficiency point with the highest performance efficiency with respect to the heat load. (Maximum point).

  However, the vehicle air conditioners 100 and 200 according to the present embodiment reduce the heat dissipation amount of the condenser 3 when the heat load is low, so that the maximum efficiency point (maximum point) of the COP is higher than the high heat load side (high The refrigeration cycle 1a, 1b is configured so as to be obtained on the outside air temperature side (for example, the coefficient of performance becomes a maximum point when the outside air temperature is 35 ° C.), and the heat load side is lower than the maximum efficiency point. By suppressing the drop of COP at the (low outside air temperature side), a high COP could be secured under a wide range of heat load conditions.

DESCRIPTION OF SYMBOLS 1a, 1b Refrigeration cycle 2 Compressor 3 Condenser 4 Expansion device 5 Evaporator 6 Liquid tank 7 Radiation amount adjustment device 10 Internal heat exchanger 11 First heat exchange unit 12 Second heat exchange unit 20 Vehicle grill device 21 Grill opening 22 Louver 23 Motor 30 Cooling fan 31 Impeller 32 Motor 41 Outside air temperature sensor 42 Pressure sensor 43 Vehicle speed sensor 44 Room temperature sensor 45 Thermo sensor 50 Refrigerant circuits 61-66 Piping 70 Bypass passage 71 Refrigerant distributor 150 Processing device 100 200 Vehicle air conditioner

Claims (10)

In a vehicle air conditioner mounted on a vehicle,
A refrigerant circuit that circulates a refrigerant by connecting a compressor, a condenser, an expansion device, and an evaporator with piping, a first heat exchange section through which the refrigerant guided from the condenser to the expansion device flows, and the evaporator A refrigeration cycle having an internal heat exchanger for exchanging heat of the refrigerant with a second heat exchange unit through which the refrigerant guided to the suction side of the compressor flows;
An outside air temperature sensor for detecting the outside air temperature of the vehicle;
A heat release amount adjusting device for adjusting the heat release amount of the refrigerant radiated by the condenser;
A vehicle air conditioner comprising: a processing device that controls the heat radiation amount adjusting device based on a value of the outside air temperature.   The processing device includes the value of the outside air temperature, (a) the pressure of the refrigerant in the high-pressure line, (b) the traveling speed of the vehicle, (c) the room temperature of the vehicle, (d) the temperature of the evaporator or the And (e) at least one selected from (a) to (e) of the amount of air blown from the blower fan to the evaporator, and the heat radiation amount adjusting device. The vehicle air conditioner according to claim 1, wherein the vehicle air conditioner is controlled. The heat radiation amount adjusting device includes a vehicle grill device that is disposed in front of the refrigeration cycle and has a grill opening that can adjust an opening degree between a minimum opening degree and a maximum opening degree,
The vehicle air conditioner according to claim 1, wherein the processing device controls an opening degree of the grill opening. The heat radiation amount adjusting device includes a cooling fan that generates a flow of air that cools the condenser,
The said processing apparatus controls the ventilation volume of the said cooling fan, The vehicle air conditioner as described in any one of Claims 1-3 characterized by the above-mentioned.   5. The vehicle air conditioner according to claim 4, wherein the processing device prioritizes control for reducing an opening degree of the grill opening rather than control for reducing an air flow rate of the cooling fan. The heat radiation amount adjusting device includes a bypass passage branched from the refrigerant circuit between the compressor and the condenser and connected to the refrigerant circuit between the condenser and the internal heat exchanger, A refrigerant distribution device that changes a ratio of the refrigerant that flows through the bypass passage among the refrigerant that has flowed out of the compressor;
The refrigeration cycle includes a liquid tank or an accumulator that separates a gaseous refrigerant and a liquid refrigerant,
The vehicular air conditioner according to any one of claims 1 to 5, wherein the processing device controls the refrigerant distribution device.   The vehicle air conditioner according to any one of claims 1 to 6, wherein the compressor is a fixed capacity type.   The vehicle air conditioner according to claim 1, wherein the processing device is mounted on an air conditioning control unit or mounted on an engine control unit.   A vehicle comprising the vehicle air conditioner according to any one of claims 1 to 8. It is a control method of the air-conditioner for vehicles according to any one of claims 1 to 8,
The vehicle air conditioner includes an operation switch for the refrigeration cycle,
The processing device recognizes that the operation switch is operated, compares the outside air temperature with a predetermined temperature, and determines that the outside air temperature is lower than the predetermined temperature, the heat dissipation amount in the condenser A control method for a vehicle air conditioner, characterized in that

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