Vehicle thermal cycle apparatus and method of determining refrigerant

Abstract

The present invention provides a vehicle heat cycle apparatus and a method of determining a refrigerant filling state, which can appropriately grasp a shortage of a refrigerant in a refrigerant cycle even in an environment in which the outside air temperature is low. A vehicle heat cycle apparatus includes: a refrigerant cycle 20 including a compressor 21, a refrigerant and heat medium heat exchanger 22, an expansion valve 24, and a heat absorption heat exchanger 25; a heat medium cycle 30 comprising a pump 31, a heat medium heating device 32 and a heat dissipation heat exchanger 34, the heat medium cycle 30 being thermally coupled to the refrigerant cycle 20 at the refrigerant and heat medium heat exchanger 22; a refrigerant temperature detector 41; a refrigerant pressure detector 42; and an outside air temperature detector 43. When it is determined that the outside air temperature is lower than the predetermined outside air temperature, switching to a determined operation mode in which an expansion valve 24 in the refrigerant cycle 20 is fully opened and a compressor 21, a pump 31, and a heat medium heating device 32 are operated is performed. Thereafter, when the refrigerant temperature exceeds a first predetermined refrigerant temperature, it is determined whether a refrigerant state grasped from the refrigerant temperature and the refrigerant pressure is lower than a pressure obtained by subtracting a predetermined pressure difference S from a saturated vapor pressure curve C of the refrigerant.

Description

Technical Field

[0001] The present invention relates to a heat cycle device installed in a vehicle and a method for determining a refrigerant filling state using the device, and more particularly to a useful technique for detecting a refrigerant filling state when the outside air temperature is low. Background Art

[0002] In the related art, as a vehicle heat cycle device, which is a combination of a refrigerant cycle (heat pump cycle) for circulating a refrigerant and a heat medium cycle for circulating a heat medium, the device disclosed in the following PTL 1 is well known.

[0003] The device includes:

[0004] A refrigerant cycle (heat pump cycle 10), including: a compressor (compressor 11) for compressing a refrigerant; a refrigerant and heat medium heat exchanger (high-temperature side water-refrigerant heat exchanger 12) for performing heat exchange between the high-pressure refrigerant discharged from the compressor and the heat medium; an expansion valve (heating expansion valve 13) for decompressing the refrigerant flowing out from the refrigerant and heat medium heat exchanger; and an endothermic heat exchanger (external heat exchanger 14) into which the refrigerant that has passed through the expansion valve flows; and

[0005] A heat medium cycle (high-pressure side heat medium circulation circuit 21), including: a pump (high-temperature side water pump 21a) for circulating the heat medium; and a heat dissipation heat exchanger (heater core 23) into which the heat medium sent out from the pump flows to allow the heat medium to dissipate heat, and the heat medium cycle is thermally coupled to the refrigerant cycle (heat pump cycle 10) through a refrigerant and heat medium heat exchanger (high-temperature side water and refrigerant heat exchanger 12).

[0006] In such a vehicle heat cycle device, when the temperature of the outside air becomes so low that a heating operation mode is set, the compressor (compressor 11) of the refrigerant cycle operates, and the pump (high-temperature side water pump 21a) of the heat medium cycle also operates. Then, in the refrigerant cycle, a heat pump cycle is constituted, in which the refrigerant circulates in the following order: compressor (compressor 11), refrigerant passage of the refrigerant and heat medium heat exchanger (high-temperature side water and refrigerant heat exchanger 12), expansion valve (heating expansion valve 13), endothermic heat exchanger (external heat exchanger 14), and compressor (compressor 11). Further, in the heat medium cycle, a heat medium circulation circuit is constituted, in which the heat medium circulates in the following order: pump (high-temperature side water pump 21a), heat medium passage of the refrigerant and heat medium heat exchanger (high-temperature side water and refrigerant heat exchanger 12), heat dissipation heat exchanger (heater core 23), and pump (high-temperature side water pump 21a).

[0007] Therefore, in the heating operation mode, the heat of the high-temperature and high-pressure refrigerant that has been discharged from the compressor (compressor 11) in the refrigerant cycle is transferred to the heat medium via the refrigerant and heat medium heat exchanger (high-temperature side water and refrigerant heat exchanger 12), the heat medium is heated in this heat exchanger, and the heat medium thus heated is supplied to the heat dissipation heat exchanger (heater core 23) so that the air passing through the heat dissipation heat exchanger can be heated.

[0008] [Citation List]

[0009] [Patent Document]

[0010] [PTL 1]

[0011] Japanese Unexamined Patent Application Publication No. 2015 - 101180 Summary of the Invention

[0012] [Technical Problem]

[0013] In this way, in the above vehicle heat circulation device, even in an environment where the outside air has such a low temperature that heating operation is required, it is necessary to operate the refrigerant cycle. Therefore, from the perspective of protecting the compressor, even when the outside air has such a low temperature, it is necessary to enable the filling state of the refrigerant in the refrigerant cycle (heat pump cycle 10) to be appropriately grasped.

[0014] In the state of pressure balance in the refrigerant cycle, for example, when the refrigerant cycle stops, the filling state of the refrigerant in the refrigerant cycle can be grasped by detecting the temperature and pressure of the refrigerant in the cycle. By detecting that the refrigerant pressure relative to the detected refrigerant temperature is lower than the saturation pressure, it is possible to grasp the shortage of the refrigerant filling amount.

[0015] However, in an environment where the outside air temperature is extremely low, such as -10°C or lower, as Figure 8 shown, the saturation pressure of the refrigerant becomes low, and the difference (ΔP) between the saturation pressure of the refrigerant and the atmospheric pressure before the compressor starts becomes very small. Therefore, when the outside air temperature becomes low, the fluctuation range of the refrigerant pressure according to the refrigerant shortage also becomes relatively small. Therefore, considering the measurement error of the refrigerant pressure sensor for detecting the refrigerant pressure, it is impossible to accurately grasp the fluctuation of the refrigerant pressure according to the refrigerant shortage, and it is difficult to appropriately determine whether the refrigerant is insufficient.

[0016] In this case, it can be considered to increase the discharged refrigerant pressure by operating the compressor. However, when the outside air temperature is low (-10°C or lower), it is less likely to absorb heat from the outside air, and an increase in the refrigerant pressure cannot be expected. This makes it difficult to determine the filling state of the refrigerant.

[0017] In addition, detecting the refrigerant flow rate by actively operating the compressor can also be considered a method of grasping the refrigerant filling state. However, when the refrigerant is insufficient, the lubricant flowing out of the compressor and into the refrigerant cycle is not collected. This poses a risk of degradation of the compressor at an early stage.

[0018] In view of this situation, the present invention has been achieved, and the main object of the present invention is to provide a vehicle heat cycle device and a method for determining the refrigerant filling state, which enable appropriate grasping of the refrigerant filling state (refrigerant shortage) in the refrigerant cycle even in an environment with a low external air temperature.

[0019] [Solution to the Problem]

[0020] To achieve the above object, a vehicle heat cycle device (1) according to the present invention includes:

[0021] A refrigerant cycle (20) in which refrigerant circulates, and the refrigerant cycle includes: a compressor (21) configured to send out refrigerant; a refrigerant and heat medium heat exchanger (22) into which the refrigerant sent out from the compressor (21) flows; an expansion valve (24) through which the refrigerant flowing out of the refrigerant and heat medium heat exchanger (22) can pass; and an endothermic heat exchanger (25) into which the refrigerant that has passed through the expansion valve (24) flows;

[0022] A heat medium cycle (30) in which heat medium circulates, and the heat medium cycle includes: a pump (31) configured to send out heat medium; a heat medium heating device (32) into which the heat medium sent out from the pump (31) flows, and the heat medium heating device (32) is capable of heating the heat medium; and a heat dissipation heat exchanger (34) into which the heat medium flowing out of the heat medium heating device (32) flows, and the heat dissipation heat exchanger (34) is capable of dissipating heat from the heat medium, and the heat medium cycle (30) is thermally coupled to the refrigerant cycle (20) through the refrigerant and heat medium heat exchanger (22);

[0023] A refrigerant temperature detector (41) configured to detect the temperature of the refrigerant in the refrigerant cycle (20);

[0024] A refrigerant pressure detector (42) configured to detect the pressure of the refrigerant in the refrigerant cycle (20);

[0025] An external air temperature detector (43) configured to detect the temperature of the external air; and

[0026] A controller (40) configured to control the operations of a refrigerant cycle (20) and a heat medium cycle (30), and configured to determine a filling state of refrigerant in the refrigerant cycle (20) using a refrigerant temperature (Tx) detected by a refrigerant temperature detector (41), a refrigerant pressure (Px) detected by a refrigerant pressure detector (42), and an outside air temperature (Toutx) detected by an outside air temperature detector (43).

[0027] An endothermic heat exchanger (25) and a heat dissipation heat exchanger (34) are provided in a blowing space (12) of an air conditioner (10) including a blower (11).

[0028] When it is determined that the outside air temperature (Toutx) is lower than a predetermined outside air temperature (Tout1), the controller (40) is configured to switch to a determination operation mode in which an expansion valve (24) is fully opened and a compressor (21), a pump (31), and a heat medium heating device (32) are operated.

[0029] After switching to the determination operation mode, when the refrigerant temperature (Tx) exceeds a first predetermined refrigerant temperature (Tref1), the controller (40) is configured to determine whether the state of the refrigerant grasped from the refrigerant temperature (Tx) and the refrigerant pressure (Px) is in a refrigerant shortage region (L) set on the pressure side lower than a saturation vapor pressure curve (C) of the refrigerant by a predetermined pressure difference (S).

[0030] Therefore, when the outside air temperature (Toutx) is lower than the predetermined outside air temperature (Tout1), a switch to the determination operation mode is performed, in which heat of a heat medium heated by a heat medium heating device in the heat medium cycle is transferred to the refrigerant in the refrigerant cycle via a refrigerant and heat medium heat exchanger. Since the refrigerant is heated, the difference between the saturation pressure of the refrigerant and the atmospheric pressure increases. Therefore, in the case where the refrigerant temperature (Tx) exceeds the first predetermined refrigerant temperature (Tref1), when the state of the refrigerant grasped from the detected refrigerant temperature (Tx) and refrigerant pressure (Px) is compared with the saturation vapor pressure curve (C), which is an inherent value of each component of the refrigerant, it is easier to grasp whether the state of the refrigerant grasped from the detected refrigerant temperature (Tx) and refrigerant pressure (Px) is lower than the pressure obtained by subtracting the predetermined pressure difference (S) from the saturation vapor pressure curve (C) of the refrigerant. Therefore, the accuracy of determining refrigerant shortage can be improved.

[0031] Here, the controller 40 may be configured to stop the blower 11 until the refrigerant shortage determination unit makes a complete determination.

[0032] This control is performed to prevent the air blown by the blower from dissipating heat from the heat dissipation heat exchanger and the heat absorption heat exchanger in the determination operation mode, thereby promoting the heating of the heat medium and promoting the heat accumulation in the refrigerant. That is, since the heat generated in the heat medium circulation and the heat accumulated in the refrigerant circulation are prevented from being dissipated by the blown air from the blower, the heat transferred from the heat medium to the refrigerant can be effectively accumulated in the refrigerant, so as to increase the refrigerant temperature at an early stage, thereby quickly determining whether the refrigerant is insufficient.

[0033] Alternatively, to achieve the above object, the vehicle heat circulation device (1A) may include:

[0034] A refrigerant circulation (20) in which the refrigerant circulates, and the refrigerant circulation includes: a compressor (21) configured to send out the refrigerant; a refrigerant and heat medium heat exchanger (22) into which the refrigerant sent out from the compressor (21) flows; an expansion valve (24) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass; a heat absorption heat exchanger (25) into which the refrigerant that has passed through the expansion valve (24) flows; a bypass passage (26) that connects the passage between the outlet portion of the refrigerant and heat medium heat exchanger (22) and the inlet portion of the expansion valve (24) to the passage between the outlet portion of the heat absorption heat exchanger (25) and the inlet portion of the compressor (21); a bypass side expansion valve (27) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass, and the bypass side expansion valve (27) is provided on the bypass passage (26); and a bypass side heat absorption heat exchanger (29) into which the refrigerant that has passed through the bypass side expansion valve (27) flows, so that the refrigerant is configured to collect the heat of the heating element (28), and the bypass side heat absorption heat exchanger (29) is provided on the bypass passage (26);

[0035] A heat medium circulation (30) in which the heat medium circulates, and the heat medium circulation includes: a pump (31) configured to send out the heat medium; a heat medium heating device (32) into which the heat medium sent out from the pump (31) flows, and the heat medium heating device (32) can heat the heat medium; and a heat dissipation heat exchanger (34) into which the heat medium flowing out from the heat medium heating device (32) flows, and the heat dissipation heat exchanger (34) can dissipate heat from the heat medium, and the heat medium circulation (30) is thermally coupled to the refrigerant circulation (20) at the refrigerant and heat medium heat exchanger (22);

[0036] A refrigerant temperature detector (41) configured to detect the temperature of the refrigerant in the refrigerant circulation (20);

[0037] A refrigerant pressure detector (42) configured to detect the pressure of the refrigerant in the refrigerant cycle (20);

[0038] An outside air temperature detector (43) configured to detect the temperature of the outside air; and

[0039] A controller (40) configured to control the operations of the refrigerant cycle (20) and the heat medium cycle (30), and configured to determine the filling state of the refrigerant in the refrigerant cycle (20) using the refrigerant temperature (Tx) detected by the refrigerant temperature detector (41), the refrigerant pressure (Px) detected by the refrigerant pressure detector (42), and the outside air temperature (Toutx) detected by the outside air temperature detector (43).

[0040] The heat absorption heat exchanger (25) and the heat dissipation heat exchanger (34) may be provided in the blowing space (12) of the air conditioner (10) including the blower (11).

[0041] When it is determined that the outside air temperature (Toutx) is lower than a predetermined outside air temperature (Tout1), the controller (40) may be configured to switch to a determination operation mode in which the expansion valve (24) is closed, the bypass side expansion valve (27) is fully opened, and the compressor (21), the pump (31), and the heat medium heating device (32) are operated.

[0042] After switching to the determination operation mode, when the refrigerant temperature (Tx) exceeds a first predetermined refrigerant temperature (Tref1), the controller (40) may be configured to determine whether the state of the refrigerant grasped from the refrigerant temperature (Tx) and the refrigerant pressure (Px) is in a refrigerant shortage region (L) set on the pressure side lower than the saturated vapor pressure curve (C) of the refrigerant by a predetermined pressure difference (S).

[0043] In this configuration, when the outside air temperature (Toutx) is lower than the predetermined outside air temperature (Tout1), the switch to the determination operation mode is performed to increase the difference between the saturated pressure of the refrigerant and the atmospheric pressure, making it easier to determine whether the state of the refrigerant grasped from the detected refrigerant temperature (Tx) and refrigerant pressure (Px) is lower than the pressure obtained by subtracting the predetermined pressure difference (S) from the saturated vapor pressure curve (C) of the refrigerant, which results in the effect of improving the accuracy of determining refrigerant shortage.

[0044] In addition, a bypass passage of the bypass heat absorption heat exchanger is provided in the refrigerant cycle, and a bypass-side heat absorption heat exchanger capable of collecting heat from the heating element is provided on the bypass passage, so that when the refrigerant temperature rises, not only the heat transferred from the heat medium via the refrigerant and the heat medium heat exchanger, but also the heat collected from the heating element can be used to rapidly increase the refrigerant temperature, thereby enabling rapid determination of whether the refrigerant is insufficient.

[0045] Here, after switching to the determination operation mode, the controller (40) can be configured to operate the blower (11) so as to ensure the blown air to the heat dissipation heat exchanger (34) through the blower (11).

[0046] In such a configuration, in the determination operation mode, the heat generated from the heating element can be used to increase the refrigerant temperature, and the heat generated by the heat medium heating device can be used to heat the passenger compartment (CR), so that the heating inside the passenger compartment (CR) can be performed in parallel with the determination of the refrigerant filling amount in the refrigerant cycle.

[0047] In the vehicle heat cycle device (1, 1A), the refrigerant temperature detector (41) and the refrigerant pressure detector (42) can be provided on one or both of the discharge side and the suction side of the compressor (21).

[0048] Although, from the perspective of protecting the compressor, the refrigerant temperature detector and the refrigerant pressure detector can be at least located on the high-pressure side (discharge side), the refrigerant temperature detector and the refrigerant pressure detector can be located on the suction side in order to grasp the average pressure of the entire refrigerant path and the amount of refrigerant on the low-pressure side.

[0049] In addition, in the vehicle heat cycle device (1, 1A), it is preferable to determine when the refrigerant cycle (20) operates after the heat medium cycle (30) has been operated.

[0050] In such a configuration, since the heat medium cycle is operated first, the heat medium temperature can be raised first, and then, by operating the refrigerant cycle, the operation time of the refrigerant cycle until a determination result is obtained can be shortened. In the case of insufficient refrigerant, long-term operation of the compressor can be avoided.

[0051] The above configuration can be regarded as a method for determining the refrigerant filling state using the vehicle heat cycle device, and can also be designated as a method for determining whether the refrigerant is insufficient after the operation mode is switched to the determination operation mode.

[0052] That is, a method for determining the refrigerant filling state using the vehicle heat cycle device (1) includes:

[0053] A refrigerant cycle (20) in which a refrigerant circulates, and the refrigerant cycle includes: a compressor (21) configured to send out the refrigerant; a refrigerant and heat medium heat exchanger (22) into which the refrigerant sent out from the compressor (21) flows; an expansion valve (24) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass; and an endothermic heat exchanger (25) into which the refrigerant that has passed through the expansion valve (24) flows;

[0054] A heat medium cycle (30) in which a heat medium circulates, and the heat medium cycle includes: a pump (31) configured to send out the heat medium; a heat medium heating device (32) into which the heat medium sent out from the pump (31) flows, and the heat medium heating device (32) is capable of heating the heat medium; and a heat dissipation heat exchanger (34) into which the heat medium flowing out from the heat medium heating device (32) flows, and the heat dissipation heat exchanger (34) is capable of dissipating heat from the heat medium, and the heat medium cycle (30) is thermally coupled to the refrigerant cycle (20) at the refrigerant and heat medium heat exchanger (22);

[0055] A refrigerant temperature detector (41) configured to detect the temperature of the refrigerant in the refrigerant cycle (20);

[0056] A refrigerant pressure detector (42) configured to detect the pressure of the refrigerant in the refrigerant cycle (20);

[0057] An outside air temperature detector (43) configured to detect the temperature of the outside air; and

[0058] A controller (40) configured to control the operations of the refrigerant cycle (20) and the heat medium cycle (30), and configured to determine the filling state of the refrigerant in the refrigerant cycle (20) using the refrigerant temperature (Tx) detected by the refrigerant temperature detector (41), the refrigerant pressure (Px) detected by the refrigerant pressure detector (42), and the outside air temperature (Toutx) detected by the outside air temperature detector (43),

[0059] The endothermic heat exchanger (25) and the heat dissipation heat exchanger (34) are provided in a blowing space (12) of an air conditioner (10) including a blower (11),

[0060] The method may include:

[0061] An operation mode switching step (S05 to S07), when it is determined that the outside air temperature (Toutx) is lower than a predetermined outside air temperature (Tout1), switching to a determination operation mode in which the expansion valve (24) is fully opened, and operating the compressor (21), the pump (31), and the heat medium heating device (32), and

[0062] The refrigerant filling state determination steps (S09 and S10), after switching to the determination operation mode, when the refrigerant temperature (Tx) exceeds the first predetermined refrigerant temperature (Tref1), determine the deviation of the actual pressure of the refrigerant from the saturation pressure of the refrigerant at this temperature, so as to determine whether the refrigerant in the refrigerant cycle (20) is insufficient according to this deviation.

[0063] Alternatively, a method for determining the refrigerant filling state using a vehicle thermal cycle device (1A) includes:

[0064] A refrigerant cycle (20) in which the refrigerant circulates, and the refrigerant cycle includes: a compressor (21) configured to send out the refrigerant; a refrigerant and heat medium heat exchanger (22) into which the refrigerant sent out from the compressor (21) flows; an expansion valve (24) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass; an endothermic heat exchanger (25) into which the refrigerant passing through the expansion valve (24) flows; a bypass passage (26) that connects the passage between the outlet part of the refrigerant and heat medium heat exchanger (22) and the inlet part of the expansion valve (24) to the passage between the outlet part of the endothermic heat exchanger (25) and the inlet part of the compressor (21); a bypass side expansion valve (27) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass, and the bypass side expansion valve (27) is provided on the bypass passage (26); and a bypass side endothermic heat exchanger (29) into which the refrigerant passing through the bypass side expansion valve (27) flows, so that the refrigerant is configured to collect the heat of the heating element (28), and the bypass side endothermic heat exchanger (29) is provided on the bypass passage (26);

[0065] A heat medium cycle (30) in which the heat medium circulates, and the heat medium cycle includes: a pump (31) configured to send out the heat medium; a heat medium heating device (32) into which the heat medium sent out from the pump (31) flows, and the heat medium heating device (32) can heat the heat medium; and a heat dissipation heat exchanger (34) into which the heat medium flowing out from the heat medium heating device (32) flows, and the heat dissipation heat exchanger (34) can dissipate heat from the heat medium, and the heat medium cycle (30) is thermally coupled to the refrigerant cycle (20) at the refrigerant and heat medium heat exchanger (22);

[0066] A refrigerant temperature detector (41) configured to detect the temperature of the refrigerant in the refrigerant cycle (20);

[0067] A refrigerant pressure detector (42) configured to detect the pressure of the refrigerant in the refrigerant cycle (20);

[0068] An outside air temperature detector (43) configured to detect the temperature of outside air; and

[0069] A controller (40) configured to control the operations of a refrigerant cycle (20) and a heat medium cycle (30), and configured to determine a refrigerant filling state of refrigerant in the refrigerant cycle (20) using a refrigerant temperature (Tx) detected by a refrigerant temperature detector (41), a refrigerant pressure (Px) detected by a refrigerant pressure detector (42), and an outside air temperature (Toutx) detected by the outside air temperature detector (43),

[0070] An endothermic heat exchanger (25) and a heat dissipation heat exchanger (34) are provided in a blowing space (12) of an air conditioner (10) including a blower (11),

[0071] The method may include:

[0072] An operation mode switching step (S15 to S17) of switching to a determination operation mode in which an expansion valve (24) is closed, a bypass-side expansion valve (27) is fully opened, and a compressor (21), a pump (31), and a heat medium heating device (32) are operated when it is determined that the outside air temperature (Toutx) is lower than a predetermined outside air temperature (Tout1), and

[0073] A refrigerant filling state determination step (S09 and S10) of, after switching to the determination operation mode, determining a deviation degree of an actual pressure of the refrigerant with respect to a saturation pressure of the refrigerant at the temperature when the refrigerant temperature (Tx) exceeds a first predetermined refrigerant temperature (Tref1), and thereby determining whether the refrigerant in the refrigerant cycle (20) is insufficient according to the deviation degree.

[0074] A method for determining a refrigerant filling state using a vehicle heat cycle device (1, 1A) may further include a compressor protection step (S12) of switching to a compressor protection mode of protecting the compressor (21) by stopping the compressor (21) when it is determined from the refrigerant filling state determination step (S09 and S10) that the refrigerant cycle (20) has insufficient refrigerant.

[0075] In a case where it is determined that the filling amount of the refrigerant is insufficient, when the compressor remains in operation, the risk of reducing the compressor performance at an early stage increases. Therefore, stopping the compressor can protect the compressor.

[0076] [Advantageous effects of the invention]

[0077] As described above, with the vehicle thermal cycle device (1, 1A) according to the present invention and the method of using the device, when it is determined that the external air temperature (Toutx) is lower than a predetermined external air temperature (Tout1), a switching to a determination operation mode is performed. In this determination operation mode, the heat of the heat medium heated in the heat medium cycle is transferred to the refrigerant in the refrigerant cycle via the refrigerant and heat medium heat exchanger, so that after the refrigerant temperature rises, it is determined whether the refrigerant is insufficient. That is, when the refrigerant temperature (Tx) exceeds a first predetermined refrigerant temperature (Tref1), it is determined whether the state of the refrigerant grasped from the refrigerant temperature (Tx) and the refrigerant pressure (Px) is in a refrigerant insufficient region (L), and the refrigerant insufficient region (L) is set on the pressure side lower than the saturated vapor pressure curve (C) of the refrigerant by a predetermined pressure difference (S). Therefore, even in an environment with an extremely low external air temperature, the filling state (refrigerant insufficiency) of the refrigerant in the refrigerant cycle can be appropriately grasped. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 FIG. is a schematic diagram showing a vehicle thermal cycle device according to a first embodiment of the present invention.

[0079] Figure 2 Each shows Figure 1 FIGS. showing the operation modes of the vehicle thermal cycle device shown. Figure 2 (a) shows the state of the determination operation mode. Figure 2 (b) shows the state of the heating operation mode. Figure 2 (c) shows the state of the dehumidifying operation mode. Figure 2 (d) shows the state of the cooling operation mode.

[0080] Figure 3 FIG. is a flowchart showing a method for determining refrigerant insufficiency by a controller in the case of using Figure 1 the vehicle thermal cycle device shown.

[0081] Figure 4 FIG. is a graph showing a method for determining refrigerant insufficiency in the refrigerant cycle.

[0082] Figure 5 FIG. is a schematic diagram showing a vehicle thermal cycle device according to a second embodiment of the present invention.

[0083] Figure 6 Each shows Figure 5 FIGS. showing the operation modes of the vehicle thermal cycle device shown. Figure 6 (a) shows the state of the determination operation mode. Figure 6 (b) shows the state of the heating operation mode. Figure 6 (c) shows the state of the dehumidifying operation mode. Figure 6(d) shows the state of the cooling operation mode.

[0084] Figure 7 is a flowchart showing a method for determining refrigerant shortage by a controller in the case of using Figure 5 the vehicle thermal cycle device shown.

[0085] Figure 8 is a graph showing the saturated vapor pressure curve of the refrigerant. Detailed Description

[0086] First Embodiment

[0087] Hereinafter, embodiments of a vehicle thermal cycle device according to the present invention will be described with reference to the drawings.

[0088] Figure 1 Shows a first embodiment of a vehicle thermal cycle device (vehicle thermal cycle device 1). The vehicle thermal cycle device 1 is installed in a vehicle V and operates according to various operation modes using a refrigerant cycle 20 and a heat medium cycle 30 thermally coupled to the refrigerant cycle 20. In particular, the vehicle thermal cycle device 1 can determine the filling state of the refrigerant in the refrigerant cycle 20.

[0089] The refrigerant circulates within the refrigerant cycle 20, and the refrigerant cycle 20 includes the following components connected in sequence by pipes: a compressor 21 for sending out the refrigerant; a refrigerant and heat medium heat exchanger 22 into which the refrigerant sent out from the compressor 21 flows; a liquid tank 23 for performing gas-liquid separation on the refrigerant flowing out from the refrigerant and heat medium heat exchanger 22; an expansion valve 24 through which the refrigerant flowing out from the liquid tank 23 can pass; and a heat absorption heat exchanger 25 into which the refrigerant that has passed through the expansion valve 24 flows.

[0090] The refrigerant is not limited to a specific type as long as the refrigerant has a composition for realizing the function. For example, a fluorocarbon medium (HFC-134a, R-1234yf) or carbon dioxide (CO2) is used.

[0091] The compressor 21 internally includes a compression mechanism for the refrigerant and has the functions of sucking in the refrigerant, compressing the refrigerant into a high-temperature and high-pressure state, and discharging the refrigerant by rotating the compression mechanism. The compressor 21 used in the present invention is not limited to a specific type as long as the compressor realizes these functions. For example, an electric compressor driven by an electric motor is used.

[0092] The liquid tank 23 is not limited to a specific type as long as the liquid tank realizes the function. Note that instead of the liquid tank 23, a liquid receiver (not shown) may be provided between the heat absorption heat exchanger 25 and the compressor 21.

[0093] As the expansion valve 24, an electronic expansion valve is used instead of a mechanical expansion valve. The opening degree of the electronic expansion valve can be appropriately adjusted by a control signal from the outside, so that by setting the opening degree to fully open, the refrigerant can pass through the electronic expansion valve without being decompressed and expanded.

[0094] The heat medium circulates within the heat medium circulation 30, which includes: a pump 31 for sending out the heat medium; a heat medium heating device 32 into which the heat medium sent out from the pump 31 flows, so that the heat medium heating device 32 can heat the heat medium; a heat dissipation heat exchanger 34 into which the heat medium flowing out from the heat medium heating device 32 flows, so that the heat dissipation heat exchanger 34 can dissipate heat from the heat medium; and a refrigerant and heat medium heat exchanger 22 into which the heat medium flowing out from the heat dissipation heat exchanger 34 flows, and the refrigerant and heat medium heat exchanger 22 is thermally coupled to the refrigerant circulation 20.

[0095] The heat medium is not limited to a specific type as long as the heat medium has a composition for realizing the function. For example, water, antifreeze, or a coolant containing a rust preventive component is used.

[0096] The heat medium heating device 32 includes a heating flow path through which the heat medium flows, and an electric heating element (such as a spiral electric heating wire) provided inside the heating flow path and heating the heat medium flowing in the heating flow path.

[0097] The refrigerant and heat medium heat exchanger 22 includes a refrigerant channel portion 22a through which the refrigerant of the refrigerant circulation 20 flows, and a heat medium channel portion 22b through which the heat medium of the heat medium circulation 30 flows. The refrigerant and heat medium heat exchanger 22 transfers heat between the refrigerant flowing in the refrigerant channel portion 22a and the heat medium flowing in the heat medium channel portion 22b, and is sometimes referred to as a water condenser.

[0098] In addition, the heat medium circulation 30 is coupled in parallel to the heat dissipation heat exchanger 34, and also includes an outside-of-vehicle heat exchanger (radiator) 35 for exchanging heat with the air outside the vehicle compartment CR. A three-way valve 36 is interposed between the heat medium heating device 32 and the heat dissipation heat exchanger 34, so that the heat medium that has flowed out from the heat medium heating device 32 can switch through the three-way valve 36 whether the heat medium is sent to the heat dissipation heat exchanger 34 or sent to the outside-of-vehicle heat exchanger 35.

[0099] The heat absorption heat exchanger 25 of the refrigerant cycle 20 and the heat dissipation heat exchanger 34 of the heat medium cycle 30 are provided in the blowing space 12 of the air conditioner 10 including the blower 11. Specifically, the air conditioner 10 is provided behind a partition (not shown) in the passenger compartment CR, and the partition divides the vehicle V into a front vehicle compartment FR and the passenger compartment CR. The internal / external air switching device 13 is provided at the most upstream of the air conditioner 10. The opening ratio of the internal air inlet 14 and the external air inlet 15 can be adjusted by the intake air valve 16. The internal and / or external air introduced into the air conditioner 10 is sucked in by the rotation of the blower 11 and sent to the heat absorption heat exchanger 25 and the heat dissipation heat exchanger 34 provided in the blowing space 12. After appropriately performing heat exchange of the air in the heat absorption heat exchanger 25 and the heat dissipation heat exchanger 34 to adjust the air to a desired temperature, the air is supplied to the passenger compartment CR via a plurality of outlets (not shown) provided in the air conditioner 10.

[0100] The heat absorption heat exchanger 25 is arranged to block the entire cross-section of the blowing space 12 in the air conditioner 10 in such a way that all the air introduced into the air conditioner 10 by the rotation of the blower 11 passes through the heat absorption heat exchanger 25. The heat dissipation heat exchanger 34 is provided downstream of the heat absorption heat exchanger 25 so as to partially block the cross-section of the blowing space 12 and form a passage bypassing the heat dissipation heat exchanger 34. An air mixing door 17 for adjusting the flow rate ratio of the air passing through the heat dissipation heat exchanger 34 and the air bypassing the heat dissipation heat exchanger 34 is provided between the heat absorption heat exchanger 25 and the heat dissipation heat exchanger 34.

[0101] Here, the air mixing door 17 can be a sliding door as shown in the figure, or can be a cantilever or butterfly rotary door, not shown.

[0102] A refrigerant temperature sensor (refrigerant temperature detector) 41 for detecting the refrigerant temperature in the refrigerant cycle 20 and a refrigerant pressure sensor (refrigerant pressure detector) 42 for detecting the refrigerant pressure in the refrigerant cycle 20 are provided on the discharge side of the compressor 21 of the refrigerant cycle 20. In addition, an outside air temperature sensor (outside air temperature detector) 43 for detecting the outside air temperature of the vehicle V is provided at an appropriate position of the vehicle V. The detection data detected by these sensors (detectors) and the control signal from the operation panel 45 are input to the controller 40 and used to control, for example, the driving state of the compressor 21, the opening degree of the expansion valve 24, the air volume blown by the blower 11, the switching of the three-way valve 36, the position of the air mixing door 17, the switching and rotational speed of the compressor 21, the switching of the pump 31, and the switching of the heat medium heating device 32.

[0103] Next, the normal operation modes (heating operation mode, dehumidifying operation mode, and cooling operation mode) for air-conditioning the interior of the passenger compartment CR using the vehicle thermal cycle device 1 having the above configuration will be described.

[0104] Reference Figure 2 (b). When the operation mode is set to the heating operation mode (the heating operation mode in the first embodiment), the controller 40 stops the compressor 21 and does not operate the refrigerant cycle 20. The pump 31 is turned on, and the heat medium cycle 30 operates. At this time, the heat medium is heated by turning on the heat medium heating device 32, and the three-way valve 36 is set to a state that allows the heat medium heating device 32 and the heat dissipation heat exchanger 34 to communicate with each other. In addition, the air mix door 17 is set at the full heat position, and the blower 11 rotates (is turned on).

[0105] Then, in the heat medium cycle 30, the heat medium that has been sent out from the pump 31 is heated by the heat medium heating device 32, and then heats the air that has been introduced into the air conditioner 10 (the air blown from the blower 11) in the heat dissipation heat exchanger 34. At this time, since the refrigerant cycle 20 is not operating, the air blown from the blower 11 is not cooled when passing through the heat absorption heat exchanger 25, but is guided to the heat dissipation heat exchanger 34, and after the air is heated by the heat dissipation heat exchanger 34, the air is supplied to the passenger compartment CR. In this case, since the refrigerant cycle 20 is not operating, the refrigerant does not actively absorb heat from the heat medium in the refrigerant and heat medium heat exchanger 22. Therefore, the heat medium that has absorbed heat in the heat dissipation heat exchanger 34 flows into the heat medium heating device 32 without overly reducing the temperature, and the heated heat medium enters the heat dissipation heat exchanger 34 again, enabling the temperature of the passenger compartment CR to rise rapidly.

[0106] Reference Figure 2 (c). When the operation mode is set to the dehumidifying operation mode, the controller 40 turns on the compressor 21 and operates the refrigerant cycle 20. At this time, the expansion valve 24 is set in the throttling state to obtain the dehumidifying function. The pump 31 is turned on, and the heat medium cycle 30 operates. At this time, the heat medium heating device 32 is turned off so as not to heat the heat medium, and the three-way valve 36 is set to a state that allows the heat medium heating device 32 and the heat dissipation heat exchanger 34 to communicate with each other. In addition, the air mix door 17 is set at the intermediate position, and the blower 11 rotates.

[0107] Then, in the refrigerant cycle 20, the high-temperature and high-pressure refrigerant discharged from the compressor 21 dissipates heat to the heat medium in the refrigerant and heat medium heat exchanger 22, and flows into the expansion valve 24 via the liquid tank 23. After being decompressed and expanded, the refrigerant flows into the heat absorption heat exchanger 25 and absorbs heat from the air that has been introduced into the air conditioner 10 (the air blown from the blower 11). That is, the air introduced into the air conditioner 10 is dehumidified.

[0108] In the hot medium circulation 30, the hot medium sent out from the pump 31 flows into the heat dissipation heat exchanger 34 without being heated by the hot medium heating device 32. At this time, since the hot medium has absorbed heat from the refrigerant in the refrigerant and hot medium heat exchanger 22 (which has been heated by the refrigerant), the hot medium flowing into the heat dissipation heat exchanger 34 has a constant amount of heat. Therefore, the air that has been dehumidified by the heat absorption heat exchanger 25 is partially guided to the heat dissipation heat exchanger 34 according to the opening degree of the air mixing door 17 and is heated, while the remaining air bypasses the heat dissipation heat exchanger 34 and is mixed and sent to the passenger compartment CR. For example, when the air mixing door 17 is close to the full cold position, dehumidifying cooling can be performed, and when the air mixing door 17 is close to the full hot position, dehumidifying heating can be performed.

[0109] Note that although the hot medium is not heated by closing the hot medium heating device 32 in the above description, the hot medium can be heated by opening the hot medium heating device 32. A dehumidifying heating operation can be performed.

[0110] In the above description, the three-way valve 36 is set to a state that allows the hot medium heating device 32 and the heat dissipation heat exchanger 34 to communicate with each other. However, alternatively, the three-way valve 36 can be set such that the hot medium flowing into the three-way valve 36 from the hot medium heating device 32 flows not only to the heat dissipation heat exchanger 34 but also to the outside-of-vehicle heat exchanger 35. Even when the air that has passed through the heat absorption heat exchanger 25 is heated (re-heated) by the heat dissipation heat exchanger 34, a dehumidifying cooling operation can be performed by reducing the amount of the hot medium flowing through the heat dissipation heat exchanger 34.

[0111] Reference Figure 2 (d). When the operation mode is set to the cooling operation mode, the controller 40 turns on the compressor 21 and operates the refrigerant cycle 20. At this time, the expansion valve 24 is set in a throttling state according to the heat load of the blown air flowing into the heat absorption heat exchanger 25 (the air flowing in the blowing space 12 in the air conditioner 10) so as to sufficiently cool the passenger compartment CR. The pump 31 is turned on, and the hot medium circulation 30 operates. At this time, the hot medium heating device 32 is turned off so as not to heat the hot medium, and the three-way valve 36 is set to a state that allows the hot medium heating device 32 and the outside-of-vehicle heat exchanger 35 to communicate with each other. In addition, the air mixing door 17 is set at the full cold position, and the blower 11 rotates.

[0112] Then, in the refrigerant cycle 20, the high-temperature and high-pressure refrigerant discharged from the compressor 21 dissipates heat to the heat medium in the refrigerant and heat medium heat exchanger 22, and flows into the expansion valve 24 via the liquid tank 23. After being decompressed and expanded, the refrigerant flows into the heat absorption heat exchanger 25 and absorbs heat from the air (the air blown by the blower 11) that has been introduced into the air conditioner 10. That is, the air introduced into the air conditioner 10 is cooled. Since the air mixing door 17 is set at the full-cool position, the air that has passed through the heat absorption heat exchanger 25 is not heated but is supplied to the passenger compartment CR as it is.

[0113] Meanwhile, in the heat medium cycle 30, the heat medium sent out from the pump 31 is not heated by the heat medium heating device 32 but flows through the outside-of-vehicle heat exchanger 35 and the refrigerant and heat medium heat exchanger 22. After absorbing heat from the refrigerant in the refrigerant and heat medium heat exchanger 22, the heat medium dissipates heat to the outside air of the vehicle V in the outside-of-vehicle heat exchanger 35. That is, the heat absorbed from the blown air by the heat absorption heat exchanger 25 is dissipated to the outside of the vehicle V via the refrigerant and heat medium heat exchanger 22 and the outside-of-vehicle heat exchanger 35, enabling the air introduced into the air conditioner 10 (the air blown by the blower 11) to be effectively cooled.

[0114] Incidentally, the case of setting the heating operation mode generally refers to the case where the outside air of the vehicle V has a low temperature. Therefore, considering the temperature adjustment in the passenger compartment CR, it is almost unnecessary to cool the blown air by operating the refrigerant cycle 20. At the same time, when the outside air temperature is low, the window glass may dew. Considering ensuring visibility, it is quite necessary to dehumidify the blown air by operating the refrigerant cycle 20. That is, it is necessary to perform a dehumidification operation or a dehumidification heating operation.

[0115] Then, as long as the refrigerant cycle 20 is operated by turning on the compressor 21, it is necessary to ensure a sufficient filling amount of the refrigerant in the refrigerant cycle 20 regardless of the conditions of the outside air temperature. When the filling amount of the refrigerant is insufficient, the compressor 21 operates excessively (for example, operates at a higher speed than expected or for a longer time than expected) without obtaining the expected dehumidification capacity. Unfortunately, this causes the inconvenience of premature aging of the compressor 21. In another case, the lubricant that should circulate in the refrigerant cycle 20 together with the circulating refrigerant stagnates in the refrigerant cycle 20 and is not sufficiently collected by the compressor 21. Unfortunately, this causes the inconvenience of premature aging of the compressor 21. Therefore, when the outside air temperature is low (at an extremely low temperature of -10°C or less), it is necessary to appropriately determine whether the filling amount of the refrigerant in the refrigerant cycle 20 is insufficient.

[0116] Here, as Figure 8As shown, the refrigerant has the physical property that the difference (ΔP) between the saturation pressure and the atmospheric pressure at low temperatures is small. The significant difference between the state where the refrigerant charge in the refrigerant cycle 20 is sufficient and the state where the refrigerant charge is insufficient is very small. In addition, considering the detection error of the commonly used refrigerant pressure sensor, it is difficult to accurately determine the refrigerant charge state (refrigerant shortage) at low temperatures. Therefore, it is desirable to evaluate whether the refrigerant is insufficient after raising the refrigerant temperature to a level where the difference between the saturation pressure and the atmospheric pressure is large enough. However, this leads to another problem, namely how to raise the refrigerant temperature in the refrigerant cycle 20 at extremely low temperatures.

[0117] In view of this, the above-mentioned refrigerant cycle 20 and the heat medium cycle 30 are used to form the following determination operation mode, so that the refrigerant charge state (whether the refrigerant is insufficient) in the refrigerant cycle 20 can be determined before the refrigerant cycle 20 is used as a dehumidifying device.

[0118] When the outside air has a low temperature, the determination operation mode is temporarily set to determine the refrigerant charge state. Hereinafter, an operation processing example of the determination operation mode including the switching control of the operation mode by the controller 40 will be described based on Figure 3 the flowchart shown.

[0119] First, when the vehicle heat cycle device 1 is started, the controller 40 determines whether the outside air temperature Toutx detected by the outside air temperature sensor 43 is lower than a predetermined outside air temperature Tout1 (step S01). The predetermined outside air temperature Tout1 is set to the limit temperature at which the difference between the saturation pressure and the atmospheric pressure of the refrigerant enables the refrigerant fluctuations caused by refrigerant shortage to be appropriately grasped. For example, the predetermined outside air temperature Tout1 is set at 5°C.

[0120] When it is determined that the outside air temperature Toutx is the predetermined outside air temperature Tout1 or higher, the difference between the saturation pressure and the atmospheric pressure of the refrigerant is a pressure difference that enables the pressure fluctuations caused by refrigerant shortage to be appropriately grasped (that is, even when the measurement error of the refrigerant pressure sensor 42 is expected, the pressure fluctuations can be reliably measured in the case of refrigerant shortage). Therefore, compared with the current state, it is not necessary to further heat the refrigerant to increase the refrigerant pressure. By determining whether the state of the refrigerant grasped from the refrigerant temperature Tx detected by the refrigerant temperature sensor 41 and the refrigerant pressure Px detected by the refrigerant pressure sensor 42 deviates from the saturation vapor pressure curve C by a predetermined pressure difference S or more (that is, whether the grasped refrigerant state is in the refrigerant shortage region L, which will be described later), it is determined whether the refrigerant is insufficient (step S02).

[0121] As a result, when there is little deviation from the saturated vapor pressure curve C and when refrigerant shortage is not recognized, conversion to one of the heating operation mode, dehumidifying operation mode, and cooling operation mode in the first embodiment is performed according to the heat load in the passenger compartment CR (step S03). On the contrary, when it is determined that the deviation from the saturated vapor pressure curve C is equal to or greater than a predetermined pressure difference S, the refrigerant filling amount in the refrigerant cycle 20 is insufficient. Therefore, when continuing to operate in one operation mode, there is a possibility that the compressor 21 may age prematurely, and thus the compressor 21 stops operating (step S04).

[0122] Incidentally, in step S01, when it is determined that the outside air temperature Toutx detected by the outside air temperature sensor 43 is lower than a predetermined outside air temperature Tout1 (when it is determined that the outside air temperature Toutx is lower than 5°C), the difference between the saturated pressure of the refrigerant and the atmospheric pressure becomes so small that it becomes difficult to detect the pressure reduction state due to refrigerant shortage within the pressure difference range. In view of this, when it is determined that the outside air temperature Toutx is lower than the predetermined outside air temperature Tout1, the following steps for switching the operation mode to the determination operation mode are performed.

[0123] Reference Figure 2 (a). The operation mode switching steps (S05 to S07) will be described. That is, in the operation mode switching steps, with the three-way valve 36 set in a state allowing the heat medium heating device 32 and the heat dissipation heat exchanger 34 to communicate with each other, the pump 31 is first started, and the heat medium heating device 32 is turned on to a state for heating the heat medium (step S05). At this time, in the air conditioner 10, the air mix door 17 is set at the full cold position, and the blower 11 is stopped (turned off) (step S06). Thereafter, in the refrigerant cycle 20, the expansion valve 24 is fully opened to allow the refrigerant to pass through without decompression and expansion, and the compressor 21 is started at a low speed to reduce the risk of premature deterioration in the case of refrigerant shortage (step S07). The low speed means a relatively slow speed with respect to the rotational speed of the compressor 21 (the rotational speed of the compression mechanism provided inside the compressor 21) during the dehumidifying operation or the cooling operation.

[0124] Note that in step S05, it is preferable that the three-way valve 36 does not allow communication between the heat medium heating device 32 and the outside-of-vehicle heat exchanger 35. This prevents the thermal energy given to the heat medium by the heat medium heating device 32 from dissipating to the outside of the vehicle V through the outside-of-vehicle heat exchanger 35. That is, it prevents the temperature of the heat medium flowing into the refrigerant and the heat medium heat exchanger 22 from decreasing.

[0125] Thus, in the hot medium circulation 30, the hot medium that has been sent out from the pump 31 is heated by the hot medium heating device 32 and flows into the heat dissipation heat exchanger 34. However, in the case where there is no heat dissipation in the heat dissipation heat exchanger 34, the hot medium flows out of the heat dissipation heat exchanger 34 and flows into the refrigerant and hot medium heat exchanger 22. Then, the hot medium dissipates heat to the refrigerant flowing in the refrigerant circulation 20 and is then sucked by the pump 31. That is, the thermal energy given to the hot medium by the hot medium heating device 32 is transferred to the refrigerant in the refrigerant and hot medium heat exchanger 22.

[0126] Since the expansion valve 24 allows the refrigerant to pass through without decompressing and expanding the refrigerant, the compressor 21 only realizes the function of a circulation pump for circulating the refrigerant in the refrigerant circulation 20. That is to say, because the refrigerant circulation 20 does not include a heat exchanger for actively dissipating thermal energy, the thermal energy of the hot medium heating device 32 that has been transferred to the refrigerant via the refrigerant and hot medium heat exchanger 22 continues to accumulate in the entire refrigerant flowing in the refrigerant circulation 20.

[0127] Here, the refrigerant circulation 20 in the operation mode switching step can start operating simultaneously with the hot medium circulation 30. However, as Figure 3 shown, preferably, the hot medium circulation 30 is first operated, and when the temperature of the hot medium is at a predetermined temperature or higher, the refrigerant circulation 20 is operated.

[0128] This operation sequence makes it possible to effectively increase the refrigerant temperature, so that the operation time of the refrigerant circulation 20 until a determination result of the refrigerant filling state is obtained can be shortened. From the perspective of protecting the compressor 21, this is also desirable.

[0129] In this way, the refrigerant temperature in the refrigerant circulation 20 can be rapidly increased. However, in this determination operation mode, there is no part for dissipating heat from the refrigerant in the refrigerant circulation 20, and this may lead to a situation where the refrigerant temperature rises excessively to a dangerous state. In view of this, when the refrigerant temperature rises excessively (when the refrigerant has accumulated so much heat that the refrigerant temperature Tx reaches the second predetermined refrigerant temperature Tref2 or becomes higher than the second predetermined refrigerant temperature Tref2: step S08), a switch is made to the heating operation mode (the heating operation mode in the first embodiment), the compressor 21 stops, the air mixing door 17 of the air conditioner 10 is set at the full heat position, and the blower 11 operates (step S11). Therefore, the thermal energy accumulated in the refrigerant is dissipated to the blown air from the heat absorption heat exchanger 25, thereby cooling the refrigerant in the refrigerant circulation 20. In addition, the thermal energy given to the hot medium is dissipated to the blown air from the heat dissipation heat exchanger 34 to reduce the temperature of the hot medium flowing into the refrigerant and hot medium heat exchanger 22, thereby reducing the heat transferred from the hot medium to the refrigerant.

[0130] In a normal determination operation mode without implementing such a safety function, the refrigerant temperature is gradually increased by switching to the determination operation mode. Therefore, when the difference between the saturation pressure of the refrigerant and the atmospheric pressure becomes a difference sufficient to appropriately detect a refrigerant shortage, that is, when the refrigerant temperature Tx detected by the refrigerant temperature sensor 41 exceeds a first predetermined refrigerant temperature Tref1 that is lower than a second predetermined refrigerant temperature Tref2, it is determined whether there is a refrigerant shortage (steps S09, S10). The first predetermined refrigerant temperature Tref1 can be referred to as a determination start temperature for starting to determine whether there is a refrigerant shortage.

[0131] Reference Figure 4 The refrigerant filling state determination steps (S09 and S10) will be described. That is, in order to determine whether there is a refrigerant shortage, a refrigerant shortage region L is set as a temperature and pressure region that enables reliable determination of a state in which the refrigerant pressure is lower than the saturation pressure due to a refrigerant shortage. After the vehicle V is boarded, the vehicle heat cycle device 1 is started to proceed to the determination operation mode. The refrigerant temperature gradually rises, and after the refrigerant temperature Tx exceeds the first predetermined refrigerant temperature Tref1, the determination of the refrigerant filling state is started (step S09). Here, the refrigerant shortage region L is a temperature and pressure region of the refrigerant obtained by subtracting a predetermined pressure difference S from the saturated vapor pressure curve C. As the predetermined pressure difference S, for example, a value approximately twice the detection error of the refrigerant pressure sensor 42 (about 0.1 MPa) is applied. Without considering the predetermined pressure difference S, when the refrigerant pressure Px slightly deviates from the saturated vapor pressure curve C of the refrigerant, it is determined that the refrigerant filling amount is insufficient, and there may be a detection error of the refrigerant pressure sensor 42 that may cause an incorrect determination that the refrigerant filling amount is insufficient although the refrigerant filling amount is actually sufficient. Then, it is determined whether the refrigerant state grasped from the actual refrigerant temperature (the refrigerant temperature Tx already detected by the refrigerant temperature sensor 41) and the actual refrigerant pressure (the refrigerant pressure Px already detected by the refrigerant pressure sensor 42) (the refrigerant state grasped by the sensor after the refrigerant temperature exceeds the first predetermined refrigerant temperature Tref1, as Figure 4 indicated by the black circle) is within the refrigerant shortage region L. When the refrigerant state is within the refrigerant shortage region L (when the refrigerant pressure Px is lower than the pressure obtained by subtracting the predetermined pressure difference S from the saturated vapor pressure curve C), it is determined that the refrigerant filling amount in the refrigerant cycle 20 is insufficient. When the refrigerant state is not within the refrigerant shortage region L (when the refrigerant pressure Px is on the higher pressure side than the refrigerant shortage region L), it is determined that the refrigerant filling amount is sufficient (step S10).

[0132] Reference Figure 3。Then, when it is determined in step S10 that the refrigerant filling amount is sufficient, the compressor 21 is unlikely to prematurely deteriorate due to insufficient refrigerant. Therefore, a conversion to the heating operation mode (the heating operation mode in the first embodiment) is performed (step S11).

[0133] The compressor protection step (S12) will be described. In the case where it is determined that the refrigerant filling amount is insufficient, when the compressor 21 continues to operate, the compressor 21 is likely to prematurely deteriorate due to insufficient dehumidifying capacity and insufficient lubricant intended to be collected by the compressor 21. Therefore, a conversion is made to the compressor protection mode to stop the compressor 21 (step S12).

[0134] Therefore, since the above-described operation mode determination has been introduced, even in an environment where the outside air temperature is so low that it is difficult to grasp the refrigerant filling state, heat is transferred from the heat medium to the refrigerant via the refrigerant and the refrigerant and heat medium heat exchanger 22, causing the refrigerant temperature (refrigerant pressure) to rapidly rise, so that the refrigerant filling state can be determined. When it is determined that the refrigerant is insufficient, the compressor 21 stops, thereby preventing premature deterioration of the compressor 21.

[0135] Second Embodiment

[0136] Figure 5 Shows a second embodiment (vehicle heat circulation device 1A) of the vehicle heat circulation device. In addition to Figure 1 the vehicle heat circulation device 1 shown, the vehicle heat circulation device 1A includes a bypass passage 26 that connects the passage between the outlet portion of the refrigerant and heat medium heat exchanger 22 and the inlet portion of the expansion valve 24 and the passage between the outlet portion of the heat absorption heat exchanger 25 and the inlet portion of the compressor 21 in the refrigerant cycle 20 to each other. On the bypass passage 26, a bypass side expansion valve 27 and a bypass side heat absorption heat exchanger 29 are also provided. The refrigerant flowing out from the refrigerant and heat medium heat exchanger 22 can pass through the bypass side expansion valve 27, and the refrigerant that has passed through the bypass side expansion valve 27 flows into the bypass side heat absorption heat exchanger 29, so that the refrigerant collects the heat of the heating element 28.

[0137] Here, the heating element 28 includes an inverter for controlling a drive motor, a battery for vehicle running, etc. The heating element 28 is thermally coupled to the bypass side heat absorption heat exchanger 29 in such a way that the refrigerant collects heat. In addition, as the bypass side expansion valve 27, an electronic expansion valve is used instead of a mechanical expansion valve. The opening degree of the electronic expansion valve can be appropriately adjusted by a control signal from the outside, so that by setting the opening degree to fully open, the refrigerant can pass through the electronic expansion valve without being decompressed and expanded. The opening degree of the bypass side expansion valve 27 can also be controlled by the controller 40.

[0138] Note that since other components are substantially the same as those in the first embodiment, the same components are denoted by the same reference numerals, and thus their description will be omitted.

[0139] Reference Figure 6 (b). In this vehicle thermal cycle device 1A, when the operation mode is set to the heating operation mode (the heating operation mode in the second embodiment), the controller 40 turns on the compressor 21 and operates the refrigerant cycle 20. At this time, the expansion valve 24 is set to closed, and the bypass-side expansion valve 27 is set to fully open. The pump 31 is turned on, and the heat medium cycle 30 operates. At this time, the heat medium is heated by turning on the heat medium heating device 32, and the three-way valve 36 is set to a state that allows the heat medium heating device 32 and the heat dissipation heat exchanger 34 to communicate with each other. In addition, the air mix door 17 is set at the full heat position, and the blower 11 rotates (is turned on).

[0140] Then, in the heat medium cycle 30, the heat medium that has been sent out from the pump 31 is heated by the heat medium heating device 32, and then heats the air blown out from the blower 11 in the heat dissipation heat exchanger 34. At this time, although the refrigerant cycle 20 operates, the expansion valve 24 is closed. Therefore, the air blown from the blower 11 is not cooled when passing through the heat absorption heat exchanger 25, but is guided to the heat dissipation heat exchanger 34, and after the air is heated by the heat dissipation heat exchanger 34, the air is supplied to the passenger compartment CR. The refrigerant flowing in the refrigerant cycle 20 does not undergo pressure reduction and expansion by passing through the bypass-side expansion valve 27 that is set to fully open, flows into the bypass-side heat absorption heat exchanger 29, and collects the heat generated by the heating element 28. When the heating operation is performed, the outside air temperature Toutx is low, and the temperature of the refrigerant flowing in the refrigerant cycle 20 is also low. Therefore, even when the refrigerant is not pressure-reduced and expanded, the refrigerant can collect the heat generated by the heating element 28. Then, as time passes, the temperature of the refrigerant gradually rises and exceeds the temperature of the heat medium in the heat medium cycle 30. The heat accumulated in the refrigerant is transferred to the heat medium in the heat medium cycle 30 via the refrigerant and heat medium heat exchanger 22, and is dissipated to the air blown out from the blower 11 via the heat dissipation heat exchanger 34.

[0141] Note that in the heating operation, although not shown, the bypass-side expansion valve 27 can be set in a throttling state to adiabatically expand the refrigerant. The refrigerant that has been adiabatically expanded by the bypass-side expansion valve 27 can effectively collect the heat generated by the heating element 28 in the bypass-side heat absorption heat exchanger 29. In addition, the refrigerant is compressed by the compressor 21 into a high temperature and high pressure, and flows into the refrigerant and heat medium heat exchanger 22, so that the refrigerant can effectively transfer the thermal energy to the heat medium in the heat medium cycle 30.

[0142] Reference Figure 6(c). When the operation mode is set to the dehumidifying operation mode, the controller 40 turns on the compressor 21 and operates the refrigerant cycle 20. At this time, the expansion valve 24 is set in the throttling state to obtain the dehumidifying function, and the bypass side expansion valve 27 is set in the throttling state to effectively collect the heat generated by the heating element 28. The pump 31 is turned on, and the heat medium cycle 30 operates. At this time, the heat medium heating device 32 is turned off so as not to heat the heat medium, and the three-way valve 36 is set to a state that allows the heat medium heating device 32 and the heat dissipation heat exchanger 34 to communicate with each other. In addition, the air mix door 17 is set at the intermediate position, and the blower 11 rotates.

[0143] Then, in the refrigerant cycle 20, the high-temperature and high-pressure refrigerant discharged from the compressor 21 dissipates heat to the heat medium in the refrigerant and heat medium heat exchanger 22, and partially flows into the expansion valve 24 via the liquid tank 23, while the remaining refrigerant flows into the bypass side expansion valve 27. The refrigerant flowing into the expansion valve 24 is decompressed and expanded by the expansion valve 24. Thereafter, the refrigerant flows into the heat absorption heat exchanger 25 and absorbs heat from the air that has been introduced into the air conditioner 10. That is, the air that has been introduced into the air conditioner 10 is dehumidified. The refrigerant flowing into the bypass side expansion valve 27 is decompressed and expanded by the bypass side expansion valve 27. Thereafter, the refrigerant collects (absorbs) the heat of the heating element 28 in the bypass side heat absorption heat exchanger 29. The refrigerant flowing out of the heat absorption heat exchanger 25 and the refrigerant flowing out of the bypass side heat absorption heat exchanger 29 converge and are sucked into the compressor 21.

[0144] In the heat medium cycle 30, the heat medium sent out from the pump 31 flows into the heat dissipation heat exchanger 34 without being heated by the heat medium heating device 32. At this time, since the heat medium has absorbed heat from the refrigerant (heated by the refrigerant) in the refrigerant and heat medium heat exchanger 22, the heat medium flowing into the heat dissipation heat exchanger 34 has a constant amount of heat. Therefore, the air that has been dehumidified by the heat absorption heat exchanger 25 is partially guided to the heat dissipation heat exchanger 34 and heated according to the opening degree of the air mix door 17, while the remaining air bypasses the heat dissipation heat exchanger 34 and is mixed and sent to the passenger compartment CR. For example, when the air mix door 17 is close to the full cold position, dehumidifying cooling can be performed, and when the air mix door 17 is close to the full hot position, dehumidifying heating can be performed.

[0145] Note that although the heat medium is not heated by turning off the heat medium heating device 32 in the above description, the heat medium can be heated by turning on the heat medium heating device 32 in order to perform the dehumidifying heating operation. Alternatively, the three-way valve 36 can be set such that, in addition to the heat dissipation heat exchanger 34, the heat medium flowing in from the heat medium heating device 32 also flows into the outside-of-vehicle heat exchanger 35 in order to perform the dehumidifying cooling operation.

[0146] ReferenceFigure 6 (d). When the operation mode is set to the cooling operation mode, the controller 40 turns on the compressor 21 and operates the refrigerant cycle 20. At this time, the expansion valve 24 is set in the throttling state to obtain the cooling function, and the bypass side expansion valve 27 is set in the throttling state to effectively collect the heat generated by the heating element 28. The pump 31 is turned on, and the heat medium cycle 30 operates. At this time, the heat medium heating device 32 is turned off so as not to heat the heat medium, and the three-way valve 36 is set in a state allowing the heat medium heating device 32 and the outside-of-vehicle heat exchanger 35 to communicate with each other. In addition, the air mix door 17 is set at the full cold position, and the blower 11 rotates.

[0147] Then, in the refrigerant cycle 20, the high-temperature and high-pressure refrigerant discharged from the compressor 21 dissipates heat to the heat medium in the refrigerant and heat medium heat exchanger 22, and a part of it flows into the expansion valve 24 via the liquid tank 23, while the remaining refrigerant flows into the bypass side expansion valve 27. The refrigerant flowing into the expansion valve 24 is decompressed and expanded by the expansion valve 24. After that, the refrigerant flows into the heat absorption heat exchanger 25 and absorbs heat from the air that has been introduced into the air conditioner 10. That is, the air that has been introduced into the air conditioner 10 is cooled. The refrigerant flowing into the bypass side expansion valve 27 is decompressed and expanded by the bypass side expansion valve 27. After that, the refrigerant collects (absorbs) the heat of the heating element 28 in the bypass side heat absorption heat exchanger 29. The refrigerant flowing out of the heat absorption heat exchanger 25 and the refrigerant flowing out of the bypass side heat absorption heat exchanger 29 converge and are sucked into the compressor 21.

[0148] Since the air mix door 17 is set at the full cold position, the air that has passed through the heat absorption heat exchanger 25 is not heated but blown out of the air conditioner 10, thereby cooling the passenger compartment CR.

[0149] At the same time, in the heat medium cycle 30, the heat medium sent out from the pump 31 is not heated by the heat medium heating device 32, but circulates through the outside-of-vehicle heat exchanger 35 and the refrigerant and heat medium heat exchanger 22. After absorbing heat from the refrigerant in the refrigerant and heat medium heat exchanger 22, the heat medium dissipates heat to the outside air of the vehicle V in the outside-of-vehicle heat exchanger 35. That is, the heat absorbed by the heat absorption heat exchanger 25 from the blown air (the air flowing in the blowing space 12 in the air conditioner 10) is dissipated to the atmosphere outside the vehicle V via the refrigerant and heat medium heat exchanger 22 and the outside-of-vehicle heat exchanger 35, so that the air introduced into the air conditioner 10 (the air blown from the blower 11) can be effectively cooled.

[0150] In the above-described second embodiment, in the heating operation mode, when the outside air temperature is low, the expansion valve 24 is closed, and the refrigerant cycle 20 sequentially has a cycle of the compressor 21, the refrigerant and heat medium heat exchanger 22, the bypass-side expansion valve 27, and the bypass-side heat absorption heat exchanger 29, so that the refrigerant cycle 20 can operate without the refrigerant flowing in the heat absorption heat exchanger 25. Therefore, when the heating operation is performed, thermal energy can be accumulated in the refrigerant circulating in the refrigerant cycle 20. That is to say, the heating operation and the determination operation can be performed simultaneously.

[0151] However, when the heating operation and the determination operation are performed simultaneously, the thermal energy given to the heat medium from the heat medium heating device 32 is distributed to the heat for heating the blown air in the heat dissipation heat exchanger 34 and the heat for heating the refrigerant in the refrigerant and heat medium heat exchanger 22. Therefore, when the heating operation and the determination operation are performed simultaneously, the heating capacity becomes lower than when the heating operation is performed alone, and the determination time becomes longer than when the determination operation is performed alone. In view of this, it is desirable to enable the configuration to perform the heating operation and the determination operation simultaneously, and to enable the configuration to perform each of these operations alone, so that these operations can be selected according to the requirements of the vehicle occupants.

[0152] Next, the determination operation mode of the refrigerant filling state in the second embodiment will be described based on Figure 7 the flowchart shown.

[0153] Steps S01 to S04 in the second embodiment are substantially the same as the steps in the first embodiment.

[0154] First, when the vehicle heat circulation device 1A is started, the controller 40 determines whether the outside air temperature Toutx detected by the outside air temperature sensor 43 is lower than a predetermined outside air temperature Tout1 (step S01).

[0155] When it is determined that the outside air temperature Toutx is equal to or higher than the predetermined outside air temperature Tout1, the difference between the saturation pressure of the refrigerant and the atmospheric pressure is a pressure difference that enables the pressure fluctuation caused by refrigerant shortage to be appropriately grasped, and it is determined whether the state of the refrigerant grasped from the detected refrigerant temperature Tx and refrigerant pressure Px deviates from the saturation vapor pressure curve C by a predetermined pressure difference S or more (that is, whether the grasped refrigerant state is in the refrigerant shortage region L), so as to determine whether the refrigerant filling amount is insufficient (step S02).

[0156] As a result, when there is little deviation from the saturated vapor pressure curve C and when no refrigerant shortage is detected, a transition is made to one of the heating operation mode, the dehumidifying operation mode, and the cooling operation mode in the second embodiment according to the heat load in the passenger compartment CR (step S03). When it is determined that the deviation from the saturated vapor pressure curve C is equal to or greater than a predetermined pressure difference S (when the refrigerant state grasped from the refrigerant temperature Tx and the refrigerant pressure Px is in the refrigerant shortage region L, which is set on the pressure side lower by the predetermined pressure difference S than the saturated vapor pressure curve C of the refrigerant), the refrigerant charge in the refrigerant cycle 20 is insufficient. Therefore, if the operation continues as it is, there is a possibility that the compressor 21 will deteriorate prematurely, and thus the compressor 21 is stopped (step S04).

[0157] Incidentally, in step S01, when it is determined that the outside air temperature Toutx is lower than a predetermined outside air temperature Tout1 (when it is determined that the outside air temperature Toutx is lower than 5°C), the following steps for switching the operation mode to the determination operation mode are performed.

[0158] Reference Figure 6 (a). The operation mode switching steps (S15 to S17) will be described. That is, in the operation mode switching steps, with the three-way valve 36 set in a state allowing the heat medium heating device 32 and the heat dissipation heat exchanger 34 to communicate with each other, the pump 31 is started and the heat medium heating device 32 is turned on to heat the heat medium (step S15). At this time, in the air conditioner 10, the air mix door 17 is set at the full cold position and the blower 11 is stopped (turned off) (step S16). Thereafter, in the refrigerant cycle 20, the expansion valve 24 is closed to prohibit the refrigerant from flowing through the heat absorption heat exchanger 25, the bypass side expansion valve 27 is fully opened to allow the refrigerant to pass through without being decompressed and expanded, and the compressor 21 is started at a low speed to reduce the risk of premature deterioration in the case of refrigerant shortage (step S17).

[0159] Note that also in step S15, it is preferable to prevent the three-way valve 36 from allowing communication between the heat medium heating device 32 and the outside heat exchanger 35 of the passenger compartment. This prevents the thermal energy given to the heat medium by the heat medium heating device 32 from dissipating to the outside of the vehicle V through the outside heat exchanger 35 of the passenger compartment. That is, it prevents the temperature of the heat medium flowing into the refrigerant and the heat medium heat exchanger 22 from decreasing.

[0160] Thus, in the hot medium circulation 30, the hot medium that has been sent out from the pump 31 is heated by the hot medium heating device 32 and flows into the heat dissipation heat exchanger 34. However, in the case where there is no heat dissipation in the heat dissipation heat exchanger 34, the hot medium flows out of the heat dissipation heat exchanger 34 and flows into the refrigerant and hot medium heat exchanger 22. Then, the hot medium dissipates heat to the refrigerant flowing in the refrigerant circulation 20 and is then sucked by the pump 31. That is, the thermal energy given to the hot medium by the hot medium heating device 32 is transferred to the refrigerant in the refrigerant and hot medium heat exchanger 22.

[0161] The expansion valve 24 is closed, and the bypass side expansion valve 27 allows the refrigerant to pass through without decompressing and expanding the refrigerant, so that the compressor 21 only functions as a circulation pump for circulating the refrigerant in the refrigerant circulation 20. That is to say, since the refrigerant circulation 20 does not include a heat exchanger for actively dissipating thermal energy, the thermal energy of the hot medium heating device 32 that has been transferred to the refrigerant via the refrigerant and hot medium heat exchanger 22 and the thermal energy of the heating element 28 that the refrigerant has collected via the bypass side heat absorption heat exchanger 29 continue to accumulate in the entire refrigerant flowing in the refrigerant circulation 20. The difference between the second embodiment and the first embodiment is that the thermal energy of the heating element 28 can be collected by the bypass side heat absorption heat exchanger 29, so that the thermal energy can accumulate in the refrigerant more quickly.

[0162] In this way, the refrigerant temperature in the refrigerant circulation 20 can be rapidly increased. However, in this determined operation mode, there is no part for dissipating the heat of the refrigerant in the refrigerant circulation 20, and this may lead to a situation where the refrigerant temperature rises excessively to a dangerous state. In view of this, when the refrigerant temperature rises excessively (when the refrigerant has accumulated so much heat that the refrigerant temperature Tx reaches the second predetermined refrigerant temperature Tref2 or becomes higher than the second predetermined refrigerant temperature Tref2: step S08), a switch to the heating operation mode (the heating operation mode in the second embodiment) is performed (step S21). The second predetermined refrigerant temperature Tref2 can be referred to as a temperature for ensuring safety (safety ensuring temperature). Therefore, the thermal energy given to the hot medium is dissipated to the blown air from the heat dissipation heat exchanger 34 to reduce the temperature of the hot medium flowing into the refrigerant and hot medium heat exchanger 22, thereby reducing the heat transferred from the hot medium to the refrigerant.

[0163] In the normal determined operation mode where this safety function is not implemented, the refrigerant temperature is gradually increased by switching to the determined operation mode. Therefore, when the difference between the saturation pressure of the refrigerant and the atmospheric pressure becomes a difference sufficient to accurately detect refrigerant shortage, that is, when the refrigerant temperature Tx exceeds the first predetermined refrigerant temperature Tref1 that is lower than the second predetermined refrigerant temperature Tref2, a determination of refrigerant shortage is performed (steps S09, S10).

[0164] Determination of insufficient refrigerant ( Figure 7 step S10 in) is performed in substantially the same manner as the determination of insufficient refrigerant in the first embodiment ( Figure 3 step S10 in).

[0165] Then, when it is determined in step S10 that the refrigerant filling amount is sufficient, there is no possibility of premature deterioration of the compressor 21 due to insufficient refrigerant. Therefore, the conversion to the heating operation mode (heating operation mode in the second embodiment) is executed (step S21).

[0166] The compressor protection step (S12) will be described. When it is determined that the refrigerant filling amount is insufficient, if the compressor 21 continues to operate, there is a possibility of premature degradation of the compressor 21 due to insufficient dehumidifying capacity and insufficient lubricant to be collected by the compressor 21. Therefore, the compressor protection mode is switched to stop the compressor 21 (step S12).

[0167] Therefore, since the above-described determination operation mode has been introduced, even in an environment where the outside air temperature is so low that it is difficult to grasp the refrigerant filling state, heat is transferred from the heat medium to the refrigerant via the refrigerant and the refrigerant heat exchanger 22, so that the refrigerant temperature (refrigerant pressure) rises rapidly, enabling the determination of the refrigerant filling state. When it is determined that the refrigerant is insufficient, the compressor 21 stops, thereby preventing premature degradation of the compressor 21. In addition, in the second embodiment, the determination of insufficient refrigerant can be performed while the heating operation is being executed. Therefore, when the outside air temperature is low, the heating operation of the passenger compartment CR can be performed in parallel with the determination operation of insufficient refrigerant.

[0168] Other embodiments

[0169] In the first and second embodiments, an example in which the refrigerant temperature sensor (refrigerant temperature detector) 41 and the refrigerant pressure sensor (refrigerant pressure detector) 42 are provided on the high-pressure side (discharge side) of the compressor 21 has been described. However, substantially the same processing can be performed using the refrigerant temperature sensor 46 and the refrigerant pressure sensor 47 provided on the low-pressure side (suction side) of the compressor 21. Alternatively, by using the refrigerant temperature sensor 41 and the refrigerant pressure sensor 42 provided on the high-pressure side (discharge side) of the compressor 21 and the refrigerant temperature sensor 46 and the refrigerant pressure sensor 47 provided on the low-pressure side (suction side) of the compressor 21, the average temperature and average pressure of the entire refrigerant cycle 20 can be grasped, and a determination regarding the refrigerant filling state (insufficient refrigerant) can be made based on the average values. The number of the refrigerant temperature sensor (refrigerant temperature detector) 41 and the refrigerant pressure sensor (refrigerant pressure detector) 42 and their positions relative to the compressor 21 are appropriately selected.

[0170] List of Reference Numerals

[0171] 1, 1A: On-vehicle Thermal Cycle Device

[0172] 10: Air conditioner

[0173] 11: Blower

[0174] 12: Blowing space

[0175] 20: Refrigerant cycle

[0176] 21: Compressor

[0177] 22: Refrigerant and heat medium heat exchanger

[0178] 24: Expansion valve

[0179] 25: Heat absorption heat exchanger

[0180] 26: Bypass passage

[0181] 27: Bypass side expansion valve

[0182] 28: Heating element

[0183] 29: Bypass side heat absorption heat exchanger

[0184] 30: Heat medium cycle

[0185] 31: Pump

[0186] 32: Heat medium heating device

[0187] 34: Heat dissipation heat exchanger

[0188] 40: Controller

[0189] 41, 46: Refrigerant temperature sensor (refrigerant temperature detector)

[0190] 42, 47: Refrigerant pressure sensor (refrigerant pressure detector)

[0191] 43: Outside air temperature sensor (outside air temperature detector)

[0192] V: Vehicle

[0193] CR: Compartment

[0194] S: Predetermined pressure difference

[0195] L: Refrigerant shortage area

Claims

1. A vehicle thermal cycle device (1), comprising: A refrigerant cycle (20) in which a refrigerant circulates, and the refrigerant cycle includes: A compressor (21) configured to send out the refrigerant; A refrigerant and heat medium heat exchanger (22) into which the refrigerant sent out from the compressor (21) flows; An expansion valve (24) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass; and An endothermic heat exchanger (25) into which the refrigerant that has passed through the expansion valve (24) flows; A heat medium cycle (30) in which a heat medium circulates, and the heat medium cycle includes: A pump (31) configured to send out the heat medium; A heat medium heating device (32) into which the heat medium sent out from the pump (31) flows, and the heat medium heating device (32) is capable of heating the heat medium; and A heat dissipation heat exchanger (34) into which the heat medium flowing out from the heat medium heating device (32) flows, and the heat dissipation heat exchanger (34) is capable of dissipating heat from the heat medium. The heat medium cycle (30) is thermally coupled to the refrigerant cycle (20) at the refrigerant and heat medium heat exchanger (22); A refrigerant temperature detector (41) configured to detect the temperature of the refrigerant in the refrigerant cycle (20); A refrigerant pressure detector (42) configured to detect the pressure of the refrigerant in the refrigerant cycle (20); An external air temperature detector (43) configured to detect the temperature of the external air; and A controller (40) configured to control the operations of the refrigerant cycle (20) and the heat medium cycle (30), and configured to determine the filling state of the refrigerant in the refrigerant cycle (20) using the refrigerant temperature (Tx) detected by the refrigerant temperature detector (41), the refrigerant pressure (Px) detected by the refrigerant pressure detector (42), and the external air temperature (Toutx) detected by the external air temperature detector (43), wherein the endothermic heat exchanger (25) and the heat dissipation heat exchanger (34) are provided in a blowing space (12) in an air conditioner (10) including a blower (11), wherein when it is determined that the external air temperature (Toutx) is lower than a predetermined external air temperature (Tout1), the controller (40) is configured to switch to a determination operation mode in which the expansion valve (24) is fully opened, and the compressor (21), the pump (31), and the heat medium heating device (32) are operated, and wherein after switching to the determination operation mode, when the refrigerant temperature (Tx) exceeds a first predetermined refrigerant temperature (Tref1), the controller (40) is configured to determine whether the state of the refrigerant grasped from the refrigerant temperature (Tx) and the refrigerant pressure (Px) is in a refrigerant shortage region (L), and the refrigerant shortage region (L) is set on the pressure side lower than a refrigerant saturation vapor pressure curve (C) by a predetermined pressure difference (S).

2. The vehicle thermal cycle device (1) according to claim 1, wherein, The controller (40) is configured to stop the blower (11) until the determination is completely made.

3. A vehicle thermal cycle device (1A), comprising: A refrigerant cycle (20) in which a refrigerant circulates, and the refrigerant cycle includes: A compressor (21) configured to send out the refrigerant; A refrigerant and heat medium heat exchanger (22) into which the refrigerant sent out from the compressor (21) flows; An expansion valve (24) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass; An endothermic heat exchanger (25) into which the refrigerant that has passed through the expansion valve (24) flows; A bypass passage (26) that connects the passage between the outlet portion of the refrigerant and heat medium heat exchanger (22) and the inlet portion of the expansion valve (24) to the passage between the outlet portion of the endothermic heat exchanger (25) and the inlet portion of the compressor (21); A bypass-side expansion valve (27) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass, and the bypass-side expansion valve (27) is provided on the bypass passage (26); and A bypass-side endothermic heat exchanger (29) into which the refrigerant that has passed through the bypass-side expansion valve (27) flows, so that the refrigerant is configured to collect the heat of the heating element (28), and the bypass-side endothermic heat exchanger (29) is provided on the bypass passage (26); A heat medium cycle (30) in which a heat medium circulates, and the heat medium cycle includes: A pump (31) configured to send out the heat medium; A heat medium heating device (32) into which the heat medium sent out from the pump (31) flows, and the heat medium heating device (32) is capable of heating the heat medium; and A heat dissipation heat exchanger (34) into which the heat medium flowing out from the heat medium heating device (32) flows, and the heat dissipation heat exchanger (34) is capable of dissipating heat from the heat medium, and the heat medium cycle (30) is thermally coupled to the refrigerant cycle (20) at the refrigerant and heat medium heat exchanger (22); A refrigerant temperature detector (41) configured to detect the temperature of the refrigerant in the refrigerant cycle (20); A refrigerant pressure detector (42) configured to detect the pressure of the refrigerant in the refrigerant cycle (20); An external air temperature detector (43) configured to detect the temperature of the external air; and A controller (40) configured to control the operations of the refrigerant cycle (20) and the heat medium cycle (30), and configured to determine the filling state of the refrigerant in the refrigerant cycle (20) using the refrigerant temperature (Tx) detected by the refrigerant temperature detector (41), the refrigerant pressure (Px) detected by the refrigerant pressure detector (42), and the external air temperature (Toutx) detected by the external air temperature detector (43), wherein the endothermic heat exchanger (25) and the heat dissipation heat exchanger (34) are provided in a blowing space (12) in an air conditioner (10) including a blower (11), When it is determined that the outside air temperature (Toutx) is lower than a predetermined outside air temperature (Tout1), the controller (40) is configured to switch to a determination operation mode in which the expansion valve (24) is closed, the bypass-side expansion valve (27) is fully opened, and the compressor (21), the pump (31), and the heat medium heating device (32) are operated, and When, after switching to the determination operation mode, the refrigerant temperature (Tx) exceeds a first predetermined refrigerant temperature (Tref1), the controller (40) is configured to determine whether the state of the refrigerant grasped from the refrigerant temperature (Tx) and the refrigerant pressure (Px) is in a refrigerant shortage region (L) that is set on the pressure side lower by a predetermined pressure difference (S) than the saturated vapor pressure curve (C) of the refrigerant.

4. The vehicle thermal cycle device (1A) according to claim 3, wherein, After switching to the determination operation mode, the controller (40) is configured to operate the blower (11) so as to ensure the blown air to the heat dissipation heat exchanger (34) through the blower (11).

5. The vehicle thermal cycle device (1, 1A) according to any one of claims 1 to 4, wherein, The refrigerant temperature detector (41) and the refrigerant pressure detector (42) are provided on one or both of the discharge side and the suction side of the compressor (21).

6. The vehicle thermal cycle device (1, 1A) according to any one of claims 1 to 4, wherein, The determination is made when the refrigerant cycle (20) is operated after the heat medium cycle (30) has been operated.

7. A method for determining a refrigerant filling state using a vehicle heat cycle device (1), comprising: A refrigerant cycle (20) in which refrigerant circulates, and the refrigerant cycle includes: A compressor (21) configured to send out refrigerant; A refrigerant and heat medium heat exchanger (22) into which the refrigerant sent out from the compressor (21) flows; An expansion valve (24) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass; and An endothermic heat exchanger (25) into which the refrigerant that has passed through the expansion valve (24) flows; A heat medium cycle (30) in which heat medium circulates, and the heat medium cycle includes: A pump (31) configured to send out heat medium; A heat medium heating device (32) into which the heat medium sent out from the pump (31) flows, and the heat medium heating device (32) is capable of heating the heat medium; and A heat dissipation heat exchanger (34) into which the heat medium flowing out from the heat medium heating device (32) flows, and the heat dissipation heat exchanger (34) is capable of dissipating heat from the heat medium, and the heat medium cycle (30) is thermally coupled to the refrigerant cycle (20) at the refrigerant and heat medium heat exchanger (22); A refrigerant temperature detector (41) configured to detect the temperature of the refrigerant in the refrigerant cycle (20); A refrigerant pressure detector (42) configured to detect the pressure of the refrigerant in the refrigerant cycle (20); An outside air temperature detector (43) configured to detect the temperature of the outside air; and A controller (40) configured to control the operations of a refrigerant cycle (20) and a heat medium cycle (30), and configured to determine the refrigerant filling state of the refrigerant in the refrigerant cycle (20) using the refrigerant temperature (Tx) detected by a refrigerant temperature detector (41), the refrigerant pressure (Px) detected by a refrigerant pressure detector (42), and the outside air temperature (Toutx) detected by an outside air temperature detector (43). An endothermic heat exchanger (25) and a heat dissipation heat exchanger (34) are provided in a blowing space (12) of an air conditioner (10) including a blower (11). The method for determining the refrigerant filling state includes: An operation mode switching step (S05 to S07) of switching to a determination operation mode when it is determined that the outside air temperature (Toutx) is lower than a predetermined outside air temperature (Tout1). In the determination operation mode, the expansion valve (24) is fully opened, and the compressor (21), the pump (31), and the heat medium heating device (32) are operated, and A refrigerant filling state determination step (S09 and S10) of, after switching to the determination operation mode, determining the deviation of the actual pressure of the refrigerant from the saturation pressure of the refrigerant at that temperature when the refrigerant temperature (Tx) exceeds a first predetermined refrigerant temperature (Tref1), and thereby determining whether the refrigerant in the refrigerant cycle (20) is insufficient based on the deviation.

8. A method for determining the refrigerant filling state using a vehicle heat cycle device (1A), including: A refrigerant cycle (20) in which a refrigerant circulates, and the refrigerant cycle includes: A compressor (21) configured to send out the refrigerant; A refrigerant and heat medium heat exchanger (22) into which the refrigerant sent out from the compressor (21) flows; An expansion valve (24) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass; An endothermic heat exchanger (25) into which the refrigerant that has passed through the expansion valve (24) flows; A bypass passage (26) that connects the passage between the outlet portion of the refrigerant and heat medium heat exchanger (22) and the inlet portion of the expansion valve (24) to the passage between the outlet portion of the endothermic heat exchanger (25) and the inlet portion of the compressor (21); A bypass side expansion valve (27) through which the refrigerant flowing out from the refrigerant and heat medium heat exchanger (22) can pass, and the bypass side expansion valve (27) is provided on the bypass passage (26); and A bypass side endothermic heat exchanger (29) into which the refrigerant that has passed through the bypass side expansion valve (27) flows, so that the refrigerant is configured to collect the heat of the heating element (28), and the bypass side endothermic heat exchanger (29) is provided on the bypass passage (26); A heat medium cycle (30) in which a heat medium circulates, and the heat medium cycle includes: A pump (31) configured to send out the heat medium; A heat medium heating device (32) into which the heat medium sent out from a pump (31) flows, and the heat medium heating device (32) is capable of heating the heat medium; and A heat dissipation heat exchanger (34) into which the heat medium flowing out from the heat medium heating device (32) flows, and the heat dissipation heat exchanger (34) is capable of dissipating heat from the heat medium. The heat medium cycle (30) is thermally coupled to the refrigerant cycle (20) at the refrigerant and heat medium heat exchanger (22); A refrigerant temperature detector (41) configured to detect the temperature of the refrigerant in the refrigerant cycle (20); A refrigerant pressure detector (42) configured to detect the pressure of the refrigerant in the refrigerant cycle (20); An outside air temperature detector (43) configured to detect the temperature of the outside air; and A controller (40) configured to control the operations of the refrigerant cycle (20) and the heat medium cycle (30), and configured to determine the filling state of the refrigerant in the refrigerant cycle (20) using the refrigerant temperature (Tx) detected by the refrigerant temperature detector (41), the refrigerant pressure (Px) detected by the refrigerant pressure detector (42), and the outside air temperature (Toutx) detected by the outside air temperature detector (43), The heat absorption heat exchanger (25) and the heat dissipation heat exchanger (34) are provided in the blowing space (12) of an air conditioner (10) including a blower (11), The method for determining the refrigerant filling state includes: An operation mode switching step (S15 to S17), when it is determined that the outside air temperature (Toutx) is lower than a predetermined outside air temperature (Tout1), switching to a determination operation mode in which the expansion valve (24) is closed, the bypass side expansion valve (27) is fully opened, and the compressor (21), the pump (31), and the heat medium heating device (32) are operated, and A refrigerant filling state determination step (S09 and S10), after switching to the determination operation mode, when the refrigerant temperature (Tx) exceeds a first predetermined refrigerant temperature (Tref1), determining the deviation of the actual pressure of the refrigerant from the saturation pressure of the refrigerant at this temperature, and thereby determining whether the refrigerant in the refrigerant cycle (20) is insufficient according to this deviation.

9. The method for determining the refrigerant filling state according to claim 7 or 8, further including a compressor protection step (S12), when it is determined from the refrigerant filling state determination step (S09 and S10) that the refrigerant cycle (20) has insufficient refrigerant, switching to a compressor protection mode for protecting the compressor (21) by stopping the compressor (21).

Images