Vehicle-mounted air conditioning device

Abstract

A vehicle-mounted air conditioning device is provided with a refrigerant circuit, a first coolant circuit, a second coolant circuit, a case covering the refrigerant circuit, a gas sensor within the case, and a controller for controlling a compressor of the refrigerant circuit. The refrigerant circuit has a compressor, a heat dissipation condenser, an expansion valve, and a heat absorption evaporator, and circulates a hydrocarbon refrigerant. The first coolant circuit circulates the coolant heated by the condenser of the refrigerant circuit, and has a radiator. The second coolant circuit circulates the coolant cooled by the evaporator of the refrigerant circuit and has a cooler core that cools the air-conditioning air. When the controller receives the starting instruction of the compressor, the compressor is prevented from being started under the condition that the gas concentration detected by the gas sensor is higher than the preset concentration.

Description

Technical Field

[0001] This specification relates to a vehicle air conditioning device, and more particularly discloses a vehicle air conditioning device using a hydrocarbon refrigerant. Background Technology

[0002] In recent years, research has been conducted on using hydrocarbon refrigerants such as propane (HC refrigerants) with low global warming coefficients as refrigerants for air conditioning systems. Because HC refrigerants are flammable, research is underway on structures to prevent refrigerant leaks in advance or to ensure safety in the event of a leak.

[0003] In Japanese Patent Application Publication No. 2022-135023, a cooler for cooling a fuel cell was disclosed, which included a pump that delivers refrigerant to the fuel cell and a technology for detecting refrigerant leakage based on the power consumption of the pump. Summary of the Invention

[0004] In vehicle air conditioning systems that use hydrocarbon refrigerants, it is desirable to be able to detect leaks of hydrocarbon refrigerant from the refrigerant circuit and limit the start-up of the compressor in the refrigerant circuit.

[0005] This specification discloses an in-vehicle air conditioning device capable of detecting leaks of hydrocarbon refrigerant from the refrigerant circuit and limiting the start-up of the compressor.

[0006] The vehicle air conditioning unit disclosed in this manual has the following features:

[0007] The refrigerant circuit includes a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption, and circulates hydrocarbon refrigerant.

[0008] The first coolant circuit circulates coolant heated by the condenser of the refrigerant circuit and has a radiator.

[0009] The second coolant circuit circulates the coolant cooled by the evaporator of the refrigerant circuit and has a cooler core for cooling the air conditioning air.

[0010] A housing that covers the refrigerant circuit;

[0011] A gas sensor, disposed within the housing, detects the gas concentration of the refrigerant outside the refrigerant circuit; and

[0012] A controller that controls the compressor.

[0013] The controller is configured to,

[0014] When the compressor start command is received, the compressor is prevented from starting if the gas concentration detected by the gas sensor is higher than a preset concentration.

[0015] According to this structure, since the refrigerant circuit dissipates heat to the coolant in the first coolant circuit and absorbs heat from the coolant in the second coolant circuit, the refrigerant circuit can be concentrated in a relatively narrow area and housed within the casing. Furthermore, in the event of refrigerant leakage from the refrigerant circuit, the refrigerant can be detected by a gas sensor inside the casing. In this case, if the gas concentration detected by the gas sensor is higher than a preset concentration, the compressor can be prevented from starting.

[0016] In the vehicle air conditioning device of the present invention, it can also be,

[0017] The preset concentration is the second concentration.

[0018] A first concentration that is lower than the second concentration is preset.

[0019] Furthermore, the controller can also be configured as follows:

[0020] Upon receiving the start command of the compressor, if the gas concentration detected by the gas sensor is lower than the first concentration, the compressor is started.

[0021] According to this structure, the compressor can be started within a housing where safety has been confirmed by a gas sensor.

[0022] In the vehicle air conditioning device of the present invention, it may also include:

[0023] An internal temperature sensor detects the internal temperature of the refrigerant circuit; and

[0024] An external temperature sensor detects the temperature outside the refrigerant circuit.

[0025] Furthermore, the controller can also be configured as follows:

[0026] When the compressor start command is received, if the gas concentration detected by the gas sensor is above the first concentration and below the second concentration,

[0027] If the temperature detected by the internal temperature sensor is lower than a temperature threshold obtained by subtracting a preset temperature from the temperature detected by the external temperature sensor, the compressor should be prevented from starting; otherwise, the compressor should be started.

[0028] According to this structure, when the gas concentration detected by the gas sensor is above a first concentration and below a second concentration, it is possible to further confirm whether there is a refrigerant leak, and based on this, the compressor can be avoided from starting. In the case of a refrigerant leak in the refrigerant circuit, the leaked refrigerant will lose heat when it vaporizes, thus the internal temperature of the refrigerant circuit will become lower than the external temperature of the refrigerant circuit. According to the above structure, if the internal temperature of the refrigerant circuit is lower than a temperature threshold obtained by subtracting a preset temperature from the external temperature of the refrigerant circuit, it is determined that there is a possibility of a refrigerant leak, thereby preventing the compressor from starting.

[0029] In the vehicle air conditioning device of the present invention, it may also include:

[0030] An internal pressure sensor detects the internal pressure of the refrigerant circuit;

[0031] An external temperature sensor that detects the temperature outside the refrigerant circuit; and

[0032] A storage device that stores a table representing the saturated vapor pressure curve of the refrigerant.

[0033] Furthermore, the controller can also use the table of the saturated vapor pressure curve to obtain the pressure of the refrigerant corresponding to the detection temperature of the external temperature sensor as the desired pressure.

[0034] Furthermore, the controller can also be configured as follows:

[0035] When the compressor start command is received, if the gas concentration detected by the gas sensor is above the first concentration and below the second concentration,

[0036] If the pressure detected by the internal pressure sensor is lower than the pressure threshold obtained by subtracting the preset pressure from the desired pressure, the compressor should be prevented from starting; otherwise, the compressor should be started.

[0037] In this structure, if the gas concentration detected by the gas sensor is above the first concentration and below the second concentration, it is possible to further confirm whether there is a refrigerant leak and avoid starting the compressor accordingly. At the point before the compressor starts, the refrigerant inside the refrigerant circuit is in a state of gas-liquid equilibrium; therefore, the relationship between the temperature and pressure of the refrigerant in the refrigerant circuit will follow the saturated vapor pressure curve of the refrigerant. Furthermore, at the point before the compressor starts, the internal temperature of the refrigerant circuit is the same as or close to the external temperature; therefore, the internal pressure of the refrigerant circuit can be estimated using the aforementioned saturated vapor pressure curve based on the external temperature of the refrigerant circuit (an estimated value of the internal temperature of the refrigerant circuit). This estimated internal pressure (called the desired pressure) is the internal pressure of the refrigerant circuit when there is no refrigerant leak. On the other hand, if there is a refrigerant leak in the refrigerant circuit, the internal pressure of the refrigerant circuit will become lower than the desired pressure. In the above structure, this principle is used to confirm whether there is a refrigerant leak. Specifically, according to the above structure, the detected pressure of the internal pressure sensor that detects the internal pressure of the refrigerant circuit is sometimes lower than the pressure threshold obtained by subtracting a preset pressure from the desired pressure. In this situation, it is determined that there is a possibility of refrigerant leakage, thus avoiding starting the compressor.

[0038] In the vehicle air conditioning device of the present invention

[0039] The controller can also be set to,

[0040] After the compressor is started, during the operation of the compressor,

[0041] The compressor is stopped when the gas concentration detected by the gas sensor increases and its rate of increase per unit time becomes higher than a preset rate of increase.

[0042] According to this structure, in the event of a refrigerant leak in the refrigerant circuit, the compressor can be stopped before the refrigerant gas concentration inside the casing becomes too high.

[0043] In the vehicle air conditioning device of the present invention, the hydrocarbon refrigerant may also be propane or a refrigerant with propane as the main component.

[0044] The vehicle disclosed in this manual is equipped with the aforementioned vehicle air conditioning device.

[0045] According to the technology disclosed in this specification, it is possible to detect leaks of hydrocarbon refrigerant from the refrigerant circuit and limit the start-up of the compressor. Attached Figure Description

[0046] Hereinafter, with reference to the accompanying drawings, the features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described, in which the same reference numerals denote the same elements, and wherein:

[0047] Figure 1 This is a schematic diagram showing the structure of an air conditioning unit.

[0048] Figure 2 This is a perspective view showing the refrigerant module.

[0049] Figure 3 This is a block diagram showing the structure of an air conditioning unit.

[0050] Figure 4 This is a flowchart illustrating the compressor's start-up control.

[0051] Figure 5 This is a flowchart representing another start-up control of the compressor.

[0052] Figure 6 This is a flowchart illustrating the control process during compressor operation.

[0053] Figure 7 This is a graph illustrating the saturated vapor pressure curve of a refrigerant. Detailed Implementation

[0054] Foreword

[0055] The embodiments will now be described with reference to the accompanying drawings. In all the drawings, equivalent elements are labeled with the same symbols, and repeated descriptions are omitted.

[0056] Air conditioning units are installed in vehicles such as automobiles. In the embodiments described below, the type of vehicle equipped with an air conditioning unit is not limited. For example, the vehicle can be an engine-powered automobile or a battery electric vehicle powered by a motor. Furthermore, the vehicle can be a hybrid electric vehicle or a plug-in hybrid electric vehicle equipped with both an engine and a motor. Additionally, the vehicle can be a fuel cell electric vehicle equipped with a fuel cell, or a pure electric vehicle that operates using electricity stored in a battery.

[0057] Air conditioning units include a refrigerant circuit that circulates hydrocarbon refrigerants (referred to as HC refrigerants). HC refrigerants are flammable. Examples of HC refrigerants include propane, butane, isobutane, ethane, ethylene, and propylene. In the refrigerant circuit, one of these HC refrigerants or a mixture of two or more of them can be used. Furthermore, in the refrigerant circuit, a mixed refrigerant can be used, which is mainly composed of one or more HC refrigerants and includes refrigerants other than HC refrigerants and various additives. For example, in the refrigerant circuit, propane or a refrigerant mainly composed of propane and including at least one of other refrigerants and additives (a propane-based refrigerant) can be used. As an example, an HC refrigerant can be R290. In this specification, hydrocarbon refrigerant refers to a pure hydrocarbon refrigerant or a refrigerant mainly composed of hydrocarbon refrigerants.

[0058] The refrigerant circuit serves as the heat source for the air conditioning unit. Along the refrigerant flow direction, the refrigerant circuit sequentially includes a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption. A liquid receiver can be installed between the condenser and the expansion valve. Furthermore, a liquid accumulator can be installed between the evaporator and the compressor.

[0059] The air conditioning unit may include: a high-temperature coolant circuit that circulates coolant heated by the condenser of the refrigerant circuit; and a low-temperature coolant circuit that circulates coolant cooled by the evaporator of the refrigerant circuit. The coolant is the heat medium, and the high-temperature coolant circuit and the low-temperature coolant circuit are each heat medium circuits.

[0060] In the implementation described below, such as Figure 1 As shown, the air conditioning unit 12 includes a first coolant circuit C1 as a high-temperature coolant circuit and a second coolant circuit C2 as a low-temperature coolant circuit. The coolant in the first and second coolant circuits C1 and C2 can be cooling water. That is, the coolant can be water without additives, water mixed with additives such as antifreeze or corrosion inhibitors, or antifreeze liquid. Furthermore, the coolant can be a liquid heat transfer medium such as oil, and is not limited thereto.

[0061] In the embodiments described below, the refrigerant circuit is located under the vehicle's front hood. Hereinafter, regardless of the presence or type of power source (engine, motor, etc.) under the front hood, the area under the front hood will be referred to as the "engine compartment".

[0062] Implementation

[0063] Figure 1 This is a schematic diagram showing the structure of the air conditioning unit 12 according to the embodiment. The air conditioning unit 12 regulates the air inside the vehicle. Figure 1As shown, the air conditioning unit 12 includes a refrigerant circuit R that serves as a heat source, a first coolant circuit C1, a second coolant circuit C2, and an air conditioning unit 70. The first coolant circuit C1 circulates a first coolant heated by the refrigerant in the refrigerant circuit R. The second coolant circuit C2 circulates a second coolant cooled by the refrigerant in the refrigerant circuit R. The air conditioning unit 70 supplies air cooled by the second coolant circulating in the second coolant circuit C2 to the vehicle interior.

[0064] The refrigerant circuit R is a closed loop that connects the compressor 20, condenser 22, receiver 28, expansion valve 24 and evaporator 26 in sequence through refrigerant piping (refrigerant flow path), and circulates hydrocarbon refrigerant (hereinafter also referred to as refrigerant).

[0065] The air conditioning unit 12 includes a heat exchanger 30. The heat exchanger 30 is integrally formed with the condenser 22 of the refrigerant circuit R, and facilitates heat exchange between the refrigerant in the refrigerant circuit R and the first coolant in the first coolant circuit C1. The heat exchanger 30 is a water-cooled condenser. The heat exchanger 30 can be, for example, a plate heat exchanger.

[0066] The first coolant circuit C1 is a closed loop formed by connecting the water pump 32, heat exchanger 30, and radiator 34 sequentially through coolant piping, thus circulating the first coolant. The radiator 34 is a heat exchanger that allows the first coolant to exchange heat with the vehicle's running airflow (Wtr). In the first coolant circuit C1, the first coolant pumped by the water pump 32 becomes hot as it flows through the heat exchanger 30 due to heat dissipation from the refrigerant at the condenser 22 in the refrigerant circuit R. The hot first coolant is then transported to the radiator 34, where it is cooled by the vehicle's running airflow (Wtr).

[0067] Furthermore, the air conditioning unit 12 includes a heat exchanger 40. The heat exchanger 40 is integrally formed with the evaporator 26 of the refrigerant circuit R, and facilitates heat exchange between the refrigerant in the refrigerant circuit R and the second coolant in the second coolant circuit C2. The heat exchanger 40 may be, for example, a plate heat exchanger.

[0068] The second coolant circuit C2 is a closed loop formed by sequentially connecting the water pump 42, the heat exchanger 40, and the cooler core 72 via coolant piping, thus circulating the second coolant. The cooler core 72 is a heat exchanger located in the air passage 75 of the air conditioning unit 70, where the second coolant exchanges heat with the air conditioning air Wac. In the second coolant circuit C2, the second coolant pumped by the water pump 42 becomes colder as it flows through the heat exchanger 40 due to the heat absorption of the refrigerant at the evaporator 26 in the refrigerant circuit R. The cooled second coolant is then transported to the cooler core 72, where it cools the air conditioning air Wac.

[0069] In the refrigerant circuit R, the refrigerant circulates as follows: Compressor 20 discharges high-pressure gaseous refrigerant, which exchanges heat with the first coolant in the first coolant circuit C1 of heat exchanger 30 in condenser 22, dissipating heat and condensing to become high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of condenser 22 is depressurized and expanded by expansion valve 24 via receiver 28, becoming low-pressure refrigerant, and flows into evaporator 26. The low-pressure refrigerant flowing into evaporator 26 exchanges heat with the second coolant in the second coolant circuit C2 of heat exchanger 40, evaporating to become gaseous refrigerant, and flows out of evaporator 26, returning to compressor 20.

[0070] The air conditioning unit 70 includes a blower 76 and an air passage 75 formed by a housing (not shown). Inside the air passage 75, the blower 76, a cooler core 72, and a heater core 74 are arranged sequentially in the airflow direction. The heater core 74 is a heat exchanger, for example, supplied with engine cooling water or cooling water heated by a PTC heater. Alternatively, the heater core 74 may be configured to be supplied with coolant heated by a heat exchanger 30.

[0071] A blower 76 introduces air into the air passage 75 through an air inlet (not shown), and forces this air through the cooler core 72 and heater core 74, thereby delivering temperature-regulated air into the vehicle interior. An air mixing valve 78 is provided inside the air passage 75, which adjusts the ratio of air flowing through the cooler core 72 to air flowing into the heater core 74. Furthermore, the air conditioning unit 70 can employ conventional heating, ventilation, and air conditioning (HVAC) technology. The air conditioning unit 70 is, for example, positioned between the vehicle's instrument panel and dashboard.

[0072] Figure 2 This is a perspective view showing the refrigerant module RM. The refrigerant circuit R is integrated to form the refrigerant module RM. Specifically, the refrigerant module RM is the component in the air conditioning unit 12 that... Figure 1 The unit that integrates equipment and flow path inside the dotted line.

[0073] like Figure 2 As shown, the refrigerant module RM includes a plate 100. The plate 100 is a fixed component for securing multiple devices. The plate 100 has a rectangular shape when viewed from above and has a constant thickness. The plate 100 can be made of, for example, aluminum. Heat exchangers 30, 24, and 40 are fixed to the upper surface 102 of the plate 100. Compressor 20 and receiver 28 are fixed to the lower surface 104 of the plate 100.

[0074] Inside the plate 100, a flow path (not shown) is provided in the form of a tunnel. Specifically, inside the plate 100, there is a refrigerant flow path for the refrigerant circuit R, a portion of a coolant flow path for the first coolant circuit C1 (a flow path for the first coolant connected to the heat exchanger 30), and a portion of a coolant flow path for the second coolant circuit C2 (a flow path for the second coolant connected to the heat exchanger 40). In addition, the refrigerant module RM, in addition to or replacing the flow paths inside the plate 100, may have piping or components for at least one of the refrigerant flow paths and coolant flow paths on the outside of the plate 100.

[0075] like Figure 2 As shown, the refrigerant module RM has ports P1 to P4. Ports P1 to P4 are located on the lower surface of one end of the plate 100 along its length. Ports P1 and P2 communicate with the flow path of the first coolant inside the plate 100 and are connected to piping of the first coolant circuit C1. Ports P3 and P4 communicate with the flow path of the second coolant inside the plate 100 and are connected to piping of the second coolant circuit C2.

[0076] Figure 3 This is a block diagram showing the structure of the air conditioning unit 12, schematically representing the cross-section of the housing 60. The air conditioning unit 12 includes the housing 60. The housing 60 includes a housing body 60a and a cover 60b. The refrigerant module RM is housed in the housing 60. The cover 60b is removed from the housing body 60a, the refrigerant module RM is housed in the housing body 60a, and then the cover 60b is installed on the housing body 60a. The refrigerant module RM is fixed to the inner surface of the housing body 60a via a bracket (not shown). Piping for the first and second coolant circuits C1 and C2 passes through the side panel of the housing body 60a and connects to ports P1 to P4 of the refrigerant module RM (see reference). Figure 2 )connect.

[0077] Furthermore, the upper surface of the cover 60b may have more than one opening. Also, the housing 60 may be constructed without the cover 60b.

[0078] The housing 60 and refrigerant module RM are located in the vehicle's engine compartment. For example... Figure 3 As shown, the base plate of the housing body 60a has a hole 62. A flexible hose 64 extending downwards from the hole 62 is connected to this hole 62. The flexible hose 64 extends from the hole 62 in the base plate toward the bottom of the vehicle body. The front end of the flexible hose 64 (not shown) can be fixed to a vehicle body structure located in the lower part (or bottom) of the engine compartment.

[0079] Through this hose 64, in the event of a refrigerant leak from the refrigerant circuit R, the refrigerant can be guided to the underside of the vehicle. Refrigerant (HC class refrigerant) is generally heavier than air, therefore it flows downwards in the hose 64. This allows the refrigerant to be released to a relatively safe location under the vehicle body.

[0080] The air conditioning unit 12 includes a gas sensor 80. The gas sensor 80 is disposed within the housing 60 and detects the refrigerant gas concentration outside the refrigerant circuit R. The gas sensor 80 is, for example, located near the bottom of the housing 60.

[0081] Furthermore, the air conditioning unit 12 is equipped with an external temperature sensor 82, an internal temperature sensor 92, and an internal pressure sensor 94.

[0082] The external temperature sensor 82 is a temperature sensor that detects the temperature outside (outside) of the refrigerant circuit R. The external temperature sensor 82 is preferably located at a position where the refrigerant will not flow when it leaks from the refrigerant circuit R. That is, the external temperature sensor 82 is preferably located at a position where, when the refrigerant leaks from the refrigerant circuit R, it can detect the temperature of air unaffected by the refrigerant, rather than the temperature of air whose temperature decreases due to the vaporization of the refrigerant. Refrigerant (HC class refrigerant) is generally heavier than air and therefore flows downwards into the housing 60. Therefore, the external temperature sensor 82 is, for example, as shown in the example... Figure 3 As shown, the sensor is preferably positioned in the housing 60 above the refrigerant circuit R or above the lower end of the refrigerant circuit R. Furthermore, a partition wall separating the refrigerant circuit R and the external temperature sensor 82 may be provided in the housing 60. Additionally, an inner wall forming a closed space within the housing 60 where the external temperature sensor 82 is disposed may be provided. Alternatively, the external temperature sensor 82 may be located on the outside of the housing 60.

[0083] The internal temperature sensor 92 is a temperature sensor that detects the internal temperature of the refrigerant circuit R. For example, the internal temperature sensor 92 detects the temperature in the refrigerant piping. Furthermore, the internal pressure sensor 94 is a pressure sensor that detects the internal pressure of the refrigerant circuit R. For example, the internal pressure sensor 94 detects the pressure in the refrigerant piping.

[0084] The air conditioning unit 12 includes a controller 50. The controller 50 may be configured as a microcomputer, such as an Electronic Control Unit (ECU). The controller 50 includes a processor 52 and a storage device 54. The processor 52 includes a Central Processing Unit (CPU), which performs various calculations and controls by running programs and control data stored in the storage device 54. The storage device 54 may include a read-only memory (ROM), a random access memory (RAM), flash memory, etc. A table 56 representing the saturated vapor pressure curve of the refrigerant is stored in the storage device 54. Figure 5 In the implementation described herein, Table 56 is used.

[0085] The controller 50 controls the compressor 20 of the refrigerant circuit R. The controller 50 receives the gas concentration detected by the gas sensor 80, the temperature detected by the external temperature sensor 82, the temperature detected by the internal temperature sensor 92, and the pressure detected by the internal pressure sensor 94.

[0086] Furthermore, a start command for the compressor 20 is input to the controller 50. This start command is a command to start the compressor 20. The start command for the compressor 20 may be issued, for example, when the user changes the air conditioning unit 12 from off to on using an operation panel (not shown), from the operation panel or an ECU connected to the operation panel. The start command for the compressor 20 may also be issued from the computer, for example, when the air conditioning unit 12 is running automatically using a computer such as the ECU (in automatic mode).

[0087] Figure 4 This is a flowchart illustrating the start-up control of compressor 20. When controller 50 receives a start command from compressor 20, it executes... Figure 4 Control of this system. Additionally, internal pressure sensors 94 and Table 56 are not used in this control system.

[0088] In step S100, the controller 50 confirms whether the detected gas concentration Gc of the gas sensor 80 is higher than a preset second concentration. This second concentration is pre-stored in the storage device 54. This second concentration is the refrigerant gas concentration set for safety considerations.

[0089] If the gas concentration Gc detected by gas sensor 80 is higher than the second concentration (S100: Yes), controller 50 enters S110. In S110, controller 50 does not start compressor 20. That is, controller 50 keeps compressor 20 in a stopped state.

[0090] On the other hand, if the gas concentration Gc detected by the gas sensor 80 is below the second concentration (S100: No), the controller 50 proceeds to S102. In S102, the controller 50 confirms whether the gas concentration Gc detected by the gas sensor 80 is below a preset first concentration. This first concentration is stored in the storage device 54. This first concentration is a gas concentration lower than the second concentration in S100. The first concentration is a refrigerant gas concentration set for safety considerations.

[0091] If the gas concentration Gc detected by gas sensor 80 is lower than the first concentration (S102: Yes), controller 50 proceeds to S112. In S112, controller 50 starts compressor 20. That is, controller 50 causes compressor 20 to start running.

[0092] On the other hand, if the gas concentration Gc detected by the gas sensor 80 is above the first concentration (S102: No), the controller 50 proceeds to S106. In S106, the controller 50 calculates a temperature threshold Tth obtained by subtracting a preset temperature prT from the detected temperature To of the external temperature sensor 82. Furthermore, the preset temperature prT is stored in the storage device 54.

[0093] Next, in S108, the controller 50 checks whether the detected temperature Ti of the internal temperature sensor 92 is lower than the temperature threshold Tth calculated in S106. If the detected temperature Ti of the internal temperature sensor 92 is lower than the temperature threshold Tth (S108: Yes), the controller 50 proceeds to S110. In S110, the controller 50 does not start the compressor 20. That is, the controller 50 keeps the compressor 20 in a stopped state.

[0094] Figure 7 This is a graph illustrating the saturated vapor pressure profile of the refrigerant. Although the saturated vapor pressure profile of the refrigerant is not used in this start-up control, it is relevant if one focuses on... Figure 7 The horizontal axis, representing "temperature," is then displayed on that axis. Figure 4 This is an example of the relationship between "the detection temperature To of the external temperature sensor 82", "the detection temperature Ti of the internal temperature sensor 92" and "the temperature threshold Tth" when the condition S108 is "yes".

[0095] On the other hand, Figure 4 In S108, if the temperature Ti detected by the internal temperature sensor 92 is above the temperature threshold Tth (S108: No), the controller 50 proceeds to S112. In S112, the controller 50 starts the compressor 20.

[0096] According to the embodiment described above, the refrigerant circuit R dissipates heat to the first coolant in the first coolant circuit C1 and absorbs heat from the second coolant in the second coolant circuit C2. Therefore, as Figure 3 As shown, the refrigerant circuit R can be concentrated within a relatively narrow area and housed within the housing 60. Furthermore, in the event of refrigerant leakage from the refrigerant circuit R, the refrigerant can be detected within the housing 60 by a gas sensor 80. At this time, if the gas concentration Gc detected by the gas sensor 80 is higher than a preset second concentration (…), Figure 4 S100: Yes), which can prevent the compressor 20 (S110) from starting.

[0097] Furthermore, according to the embodiment described above, when the gas concentration Gc detected by the gas sensor 80 is lower than a first concentration (S102: Yes), the compressor 20 is started (S112), where the first concentration is lower than the second concentration. Therefore, the compressor 20 can be started within the housing 60, where safety has been confirmed by the gas sensor 80.

[0098] Furthermore, according to the embodiment described above, if the gas concentration Gc detected by the gas sensor 80 is above the first concentration and below the second concentration (S102: No), it is possible to further confirm whether there is a refrigerant leak, and in this case, the compressor 20 can be avoided from starting. In the case of a refrigerant leak in the refrigerant circuit R, the leaked refrigerant will lose heat when it vaporizes, therefore the internal temperature Ti of the refrigerant circuit R is lower than the external temperature To of the refrigerant circuit R. According to the embodiment described above, the internal temperature Ti of the refrigerant circuit R is sometimes lower than the temperature threshold Tth obtained by subtracting a preset temperature prT from the external temperature To of the refrigerant circuit R (S108: Yes). In this case, it is determined that there is a possibility of a refrigerant leak, thereby preventing the compressor 20 from starting (S110).

[0099] Alternatively, as another implementation, when the controller 50 receives a start command from the compressor 20, the gas concentration Gc detected by the gas sensor 80 may sometimes be higher than a preset concentration (e.g., the second concentration mentioned above). It is also possible to configure the controller 50 to avoid starting the compressor 20 in this case, and to start the compressor 20 otherwise (when the detected gas concentration Gc is below the preset concentration).

[0100] Another start control

[0101] Figure 5 This is a flowchart illustrating another start-up control of compressor 20. When controller 50 receives a start command from compressor 20, it executes... Figure 5 The control is in place. Additionally, the internal temperature sensor 92 is not used in this control.

[0102] Figure 5 S200 and S202 and Figure 4 S100 and S102 are the same judgments, and the corresponding judgment results are... Figure 5 S210 and S212 are also for... Figure 4 The processing is the same as S110 and S112. Therefore, it is omitted. Figure 5 Explanation of S200 and S202.

[0103] S204 is the procedure for cases where the determination in S202 is negative. Specifically, S204 is the procedure for cases where the detected gas concentration Gc of the gas sensor 80 is above the first concentration and below the second concentration. In S204, the controller 50 uses Table 56 of the refrigerant's saturated vapor pressure curve to obtain the refrigerant pressure corresponding to the detection temperature To of the external temperature sensor 82 as the desired pressure eP. Table 56 is pre-stored in the storage device 54.

[0104] Figure 7 This is a graph illustrating the saturated vapor pressure curve of a refrigerant. The saturated vapor pressure curve represents the relationship between the temperature and pressure of the refrigerant in refrigerant circuit R when the refrigerant is in a state of vapor-liquid equilibrium, i.e., when compressor 20 is not running. Figure 7 In this context, the refrigerant pressure corresponding to the detected temperature To by the external temperature sensor 82 is represented by the symbol Po (desired pressure eP). The controller 50 obtains the desired pressure eP (Po) corresponding to the external temperature To from Table 56 of the saturated vapor pressure curve.

[0105] exist Figure 5 In S206, the controller 50 calculates the pressure threshold Pth by subtracting the preset pressure prP from the desired pressure eP. Furthermore, the preset pressure prP is stored in the storage device 54.

[0106] Next, in S208, the controller 50 checks whether the detected pressure Pi of the internal pressure sensor 94 is lower than the pressure threshold Pth calculated in S206. If the detected pressure Pi of the internal pressure sensor 94 is lower than the pressure threshold Pth (S208: Yes), the controller 50 proceeds to S210. In S210, the controller 50 does not start the compressor 20. That is, the controller 50 keeps the compressor 20 in a stopped state.

[0107] exist Figure 7 The text shows that in Figure 5 This is an example of the relationship between "expected pressure eP", "detected pressure Pi of internal pressure sensor 94" and "pressure threshold Pth" when the condition S208 is "yes".

[0108] On the other hand, Figure 5In S208, if the pressure Pi detected by the internal pressure sensor 94 is above the pressure threshold Pth (S208: No), the controller 50 proceeds to S212. In S212, the controller 50 starts the compressor 20.

[0109] In another start-up control described above, if the gas concentration detected by the gas sensor 80 is above the first concentration and below the second concentration (S202: No), it is possible to further confirm whether there is a refrigerant leak and avoid starting the compressor 20 accordingly.

[0110] Before compressor 20 starts, the refrigerant inside refrigerant circuit R is in a state of vapor-liquid equilibrium. Therefore, the temperature and pressure relationship of the refrigerant in refrigerant circuit R will follow the saturated vapor pressure curve of the refrigerant. Furthermore, before compressor 20 starts, assuming there is no refrigerant leak in refrigerant circuit R, the internal temperature Ti of refrigerant circuit R is the same as or close to the external temperature To. Therefore, using the aforementioned saturated vapor pressure curve, the internal pressure Pi of refrigerant circuit R can be estimated based on the external temperature To (an estimated value of the internal temperature Ti of refrigerant circuit R). This estimated internal pressure Pi is the desired pressure eP, which is the internal pressure Pi of refrigerant circuit R when there is no refrigerant leak. On the other hand, if there is a refrigerant leak in refrigerant circuit R, the internal pressure Pi of refrigerant circuit R is lower than the desired pressure eP. In the above-described start-up control, this principle is used to confirm whether there is a refrigerant leak. Specifically, according to the above-described start-up control, the detected pressure Pi of the internal pressure sensor 94, which detects the pressure inside the refrigerant circuit R, is sometimes lower than the pressure threshold Pth obtained by subtracting the preset pressure prP from the desired pressure eP (S208: Yes). In this case, it is determined that there is a possibility of refrigerant leakage, thereby preventing the compressor 20 from starting (S210).

[0111] Control during compressor operation

[0112] Figure 6 This is a flowchart illustrating the control process during the operation of compressor 20. Controller 50 can... Figure 4 or Figure 5 After starting the compressor 20 using either the start control or general start control, the following steps are executed: Figure 6 Control. Figure 6 The control is executed repeatedly in a pre-set cycle.

[0113] In step S300, the controller 50 checks whether the detected gas concentration Gc of the gas sensor 80 has increased, and whether the rate of increase Gci of the detected gas concentration Gc per unit time has become higher than a preset rate of increase prGci. The unit time can be, for example, 1 second, 10 seconds, 30 seconds, 60 seconds, 120 seconds, 180 seconds, etc. The rate of increase Gci is the amount of increase in gas concentration Gc per unit time. Furthermore, the preset rate of increase prGci is stored in the storage device 54.

[0114] If the rate of increase of the detected gas concentration Gc per unit time, Gci, becomes higher than the preset rate of increase prGci (S300: Yes), the controller 50 stops the compressor 20. On the other hand, if the detected gas concentration Gc does not increase or the rate of increase of the detected gas concentration Gc per unit time, Gci, is lower than the preset rate of increase prGci (S300: No), the controller 50 maintains the operation of the compressor 20.

[0115] According to this control, when a refrigerant leak occurs in the refrigerant circuit R, the compressor 20 can be stopped before the refrigerant gas concentration inside the housing 60 becomes high.

[0116] Alternatively, as another implementation, the controller 50 monitors the detected gas concentration Gc of the gas sensor 80 at a preset cycle during the operation of the compressor 20. Sometimes, the detected gas concentration Gc becomes higher than a preset concentration (e.g., the second concentration mentioned above). It can also be configured to stop the compressor 20 in this case, and otherwise (if the detected gas concentration Gc is below the preset concentration) maintain the operation of the compressor 20.

Claims

1. A vehicle-mounted air conditioning device, characterized in that, have: The refrigerant circuit includes a compressor, a condenser for heat dissipation, an expansion valve, and an evaporator for heat absorption, and circulates hydrocarbon refrigerant. The first coolant circuit circulates coolant heated by the condenser of the refrigerant circuit and has a radiator. The second coolant circuit circulates the coolant cooled by the evaporator of the refrigerant circuit and has a cooler core for cooling the air conditioning air. A housing that covers the refrigerant circuit; A gas sensor, disposed within the housing, detects the gas concentration of the refrigerant outside the refrigerant circuit; and The controller controls the compressor. The controller is configured to, When the compressor start command is received, the compressor is prevented from starting if the gas concentration detected by the gas sensor is higher than a preset concentration.

2. The vehicle air conditioning device according to claim 1, characterized in that, The preset concentration is the second concentration. A first concentration that is lower than the second concentration is preset. The controller is configured to, Upon receiving the start command of the compressor, if the gas concentration detected by the gas sensor is lower than the first concentration, the compressor is started.

3. The vehicle air conditioning device according to claim 2, characterized in that, have: An internal temperature sensor detects the internal temperature of the refrigerant circuit; and An external temperature sensor detects the temperature outside the refrigerant circuit. The controller is configured to, When the compressor start command is received, if the gas concentration detected by the gas sensor is above the first concentration and below the second concentration, If the temperature detected by the internal temperature sensor is lower than a temperature threshold obtained by subtracting a preset temperature from the temperature detected by the external temperature sensor, the compressor should be prevented from starting; otherwise, the compressor should be started.

4. The vehicle air conditioning device according to claim 2, characterized in that, have: An internal pressure sensor detects the internal pressure of the refrigerant circuit; An external temperature sensor that detects the temperature outside the refrigerant circuit; and Storage device that stores a table representing the saturated vapor pressure curve of the refrigerant. The controller uses the table of saturated vapor pressure curves to obtain the refrigerant pressure corresponding to the detected temperature of the external temperature sensor as the desired pressure. The controller is configured to, When the compressor start command is received, if the gas concentration detected by the gas sensor is above the first concentration and below the second concentration, If the pressure detected by the internal pressure sensor is lower than the pressure threshold obtained by subtracting the preset pressure from the desired pressure, the compressor should be prevented from starting; otherwise, the compressor should be started.

5. The vehicle air conditioning device according to any one of claims 1 to 4, characterized in that, The controller is configured to, After the compressor is started, during the operation of the compressor, The compressor is stopped when the gas concentration detected by the gas sensor increases and its rate of increase per unit time becomes higher than a preset rate of increase.

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