JP2020104591A - Vehicular air conditioner - Google Patents

Abstract

To provide a vehicular air conditioner with a refrigeration cycle capable of avoiding an excessive decompression state in an accumulator while sufficiently exhibiting a temperature control function required for the vehicular air conditioner.SOLUTION: A vehicular air conditioner includes at least: a refrigeration cycle 80 having a compressor 6, an outdoor heat exchanger 4, an expansion device 12, an evaporator 3 and an accumulator 10 and formed by connecting these elements in this order by piping; a bypass passage 43 that connects a refrigerant inlet pipe 41 for causing a refrigerant circulating in the refrigeration cycle to flow into the accumulator and a refrigerant outlet pipe 42 for causing a refrigerant to flow out from the accumulator with each other outside the accumulator and enables the refrigerant to flow in a short-circuit manner; a valve gear 40 provided in the bypass passage and having an opening/closing function; and a control device 23 controlling the compressor and the valve gear.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a vehicle air conditioner including a refrigeration cycle having an accumulator.

In a refrigeration cycle having an accumulator on the upstream side of the compressor, the refrigerant may boil inside the accumulator immediately after the compressor is activated, and abnormal noise may occur. Therefore, there is provided a technique aiming at suppressing the sound and the decrease in boiling (see, for example, Patent Document 1).

In Patent Document 1, the stirring device is driven by using the flow of the refrigerant flowing into the accumulator to stir the liquid refrigerant stored inside the accumulator, and aims to suppress the boiling state.

Further, there is disclosed a concept in which a vent hole is provided above the refrigerant outflow pipe inside the accumulator to short-circuit the gas-phase refrigerant inside the accumulator (for example, see Patent Document 2).

JP, 2017-058070, A JP, 2000-088402, A

However, the technique of Patent Document 1 has a drawback that the internal structure of the accumulator is complicated because the stirring device 90 is installed.

Further, in the technique of Patent Document 2, it is necessary to suck out the lubricating oil dissolved therein from the liquid refrigerant stored in the lower portion of the inside of the accumulator, and the refrigerant outflow pipe extending to the lower portion of the inside of the accumulator is constant at the lower end. It is indispensable to exert the suction force of the above, and the vent hole as shown by the reference numeral 17 in Patent Document 2 cannot be set large unexpectedly.

By the way, the reason why the liquid refrigerant boils immediately after the start of the compressor is that the internal space of the accumulator is rapidly depressurized. For this reason, for example, control may be performed on the number of revolutions immediately after the compressor is started (the number of revolutions may be kept low) to prevent excessive refrigerant suction, but the rapid cooling capacity or rapid cooling required for the refrigeration cycle may be considered. There is a problem that heating capacity cannot be obtained sufficiently.

Therefore, the present disclosure provides a vehicle air conditioner having a refrigeration cycle capable of avoiding an excessively depressurized state inside the accumulator while sufficiently exerting a required temperature adjusting function for the vehicle air conditioner required. With the goal.

The inventors of the present invention have made diligent studies and connected a refrigerant inlet pipe for flowing a refrigerant circulating in the refrigeration cycle to the accumulator and a refrigerant outlet pipe for discharging the refrigerant from the accumulator outside the accumulator to short-circuit and distribute the refrigerant. It was found that the generation of abnormal noise due to bumping can be suppressed by providing such a bypass passage, and the present invention has been completed. That is, the vehicle air conditioner according to the present invention includes at least a compressor, an outdoor heat exchanger, an expansion device, an evaporator, and an accumulator, a refrigeration cycle connected by pipes in this order, and a refrigerant that circulates through the refrigeration cycle. Is connected to the refrigerant inlet pipe flowing into the accumulator and the refrigerant outlet pipe flowing out of the refrigerant from the accumulator outside the accumulator, and the bypass passage through which the refrigerant can be short-circuited and is provided in the bypass passage. A valve device having an open/close function, and at least a control device that controls the compressor and the valve device.

In the vehicle air conditioner according to the present invention, it is preferable that the valve device is an opening/closing valve that allows or blocks the flow of the refrigerant in the bypass passage. It is possible to control the flow of the refrigerant in the bypass passage with a simple structure.

In the vehicle air conditioner according to the present invention, it is preferable that the valve device is a three-way valve arranged at a confluence point of the bypass passage and the refrigerant outlet pipe. It is possible to control the flow of the refrigerant in the bypass passage with a simple structure.

In the vehicle air conditioner according to the present invention, further has a refrigerant temperature detecting means capable of detecting the temperature of the liquid phase refrigerant inside the accumulator, the compressor is an electric type, the control device, the compression The engine is started at a specified rotation speed, and the flow of the refrigerant in the bypass passage is allowed by the valve device, and then the rotation speed specified by the compressor and the refrigerant temperature detection means are obtained. From the temperature information, the estimated superheat degree Test of the vapor phase refrigerant inside the accumulator when the flow of the refrigerant in the bypass passage is shut off is calculated, and the estimated superheat degree Test and a predetermined threshold superheat degree Tdef are calculated. In comparison, when the estimated superheat degree Test falls below the threshold superheat degree Tdef, it is preferable that the flow of the refrigerant in the bypass passage is shut off by the valve device. It is possible to estimate the valve closing timing of the valve device and accurately suppress the occurrence of bumping.

In the vehicle air conditioner according to the present invention, it is preferable that the temperature sensor portion of the refrigerant temperature detecting means is arranged below the center in the internal space of the accumulator or on the outer bottom surface of the accumulator. It is possible to more accurately estimate the valve closing timing of the valve device, and as a result, it is possible to more accurately suppress the occurrence of bumping.

In the vehicle air conditioner according to the present invention, the control device allows the flow of the refrigerant in the bypass passage by the valve device at the time of starting the compressor, and then, after a predetermined time has elapsed, the control device It is preferable that the flow of the refrigerant in the bypass passage is shut off by the valve device. Even without providing the coolant temperature detection means, it is possible to accurately suppress the occurrence of bumping with a simple configuration.

In the vehicle air conditioner according to the present invention, the vehicle further has an outside temperature detecting means, and the control means is configured to, when the outside temperature obtained from the outside temperature detecting means is below a predetermined temperature, when the compressor is started. It is preferable that the flow of the refrigerant in the bypass passage is allowed by the valve device and the flow of the refrigerant in the bypass passage is shut off by the valve device when the vehicle exterior temperature is equal to or higher than a predetermined temperature. By using the vehicle exterior temperature detecting means, it is possible to accurately suppress the occurrence of bumping with a simple configuration.

According to the present disclosure, there is provided a vehicle air conditioner having a refrigeration cycle capable of avoiding an excessively depressurized state inside the accumulator while sufficiently exerting the required temperature adjusting function for the vehicle air conditioner required. be able to.

It is a schematic diagram showing the 1st example of composition of the refrigerating cycle for cooling in the air-conditioner for vehicles concerning this embodiment. It is the schematic which shows the 1st example of the accumulator containing a bypass passage. It is the schematic which shows the 2nd example of the accumulator containing a bypass passage. It is a schematic diagram showing the 3rd example of the accumulator containing a bypass passage. It is a schematic diagram showing the 2nd example of composition of the refrigerating cycle in the air-conditioner for vehicles concerning this embodiment. It is a schematic diagram showing the 3rd example of composition of the refrigerating cycle in the air-conditioner for vehicles concerning this embodiment. It is a schematic diagram showing the 4th example of composition of the refrigerating cycle in the air-conditioner for vehicles concerning this embodiment. It is a schematic diagram showing the 5th example of composition of the refrigerating cycle in the air-conditioner for vehicles concerning this embodiment. It is a schematic diagram showing the state where the flow of the refrigerant in the bypass passage is "permitted" in the accumulator of the first example. It is a schematic diagram showing the state where the flow of the refrigerant in the bypass passage is "blocked" in the accumulator of the first example. It is a flowchart which shows the 1st example of control of the flow of the refrigerant in a bypass passage at the time of starting a compressor. It is a schematic diagram showing the state where the flow of the refrigerant in the bypass passage is "permitted" in the accumulator of the second example. It is a schematic diagram showing the state where the flow of the refrigerant in the bypass passage is "blocked" in the accumulator of the second example. It is a flowchart which shows the 2nd example of control of the flow of the refrigerant in a bypass passage at the time of starting a compressor. It is a flowchart which shows the 3rd example of control of the flow of the refrigerant in a bypass passage at the time of starting a compressor.

Hereinafter, one aspect of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In addition, in the present specification and the drawings, components having the same reference numerals indicate the same components. Various modifications may be made as long as the effects of the present invention are exhibited.

The vehicle air conditioner according to the present embodiment will be described with reference to FIGS. 1 and 2. The vehicle air conditioner according to the present embodiment includes at least a compressor 6, an outdoor heat exchanger 4, an expansion device 12, an evaporator 3, and an accumulator 10, and a refrigeration cycle 80 connected by piping in this order, and a refrigeration cycle. A refrigerant inlet pipe 41 for flowing the refrigerant circulating through 80 into the accumulator 10 and a refrigerant outlet pipe 42 for discharging the refrigerant from the accumulator 10 are connected outside the accumulator 10, and a bypass passage 43 that short-circuits the refrigerant to allow circulation. A valve device 40 provided in the bypass passage 43 and having an opening/closing function, and at least a control device 23 for controlling the compressor 6 and the valve device 40 are provided.

(First example of refrigeration cycle)
As shown in FIG. 1, the basic configuration of the refrigerating cycle for cooling includes a compressor 6, an outdoor heat exchanger 4, an expansion device 12, an evaporator 3, and an accumulator 10. The compressor 6 sucks and compresses the refrigerant. The compressor 6 is rotationally driven by a vehicle running engine (not shown) via a pulley 63, a belt and the like. As the compressor 6, either a variable capacity type compressor or a fixed capacity type compressor may be used. If an electric compressor is used as the compressor 6, the refrigerant discharge capacity can be adjusted by adjusting the rotation speed of the electric motor. In addition, it is possible to eliminate the need for connection to the vehicle running engine via a belt or the like. The high-pressure vapor-phase refrigerant discharged from the compressor 6 flows into the outdoor heat exchanger 4, where it exchanges heat with the outside air to be cooled and condensed. The liquid refrigerant condensed in the outdoor heat exchanger 4 is then decompressed to a low pressure by the expansion device 12 and becomes a mist-like gas-liquid two-phase state. The expansion device 12 comprises an orifice, a fixed throttle such as a nozzle, or an appropriate variable throttle. In the evaporator 3, the low-pressure refrigerant after depressurization absorbs heat from the air blown by the air-conditioning fan (not shown) and evaporates. The evaporator 3 is arranged in an air conditioning case (not shown), and the cold air cooled by the evaporator 3 is blown out into the vehicle compartment after its temperature is adjusted by a heater core (not shown). The refrigerant that has passed through the evaporator 3 is separated into gas and liquid by the accumulator 10 and then sucked into the compressor 6. The accumulator 10 separates the refrigerant flowing out of the evaporator 3 into a gas-phase refrigerant and a liquid-phase refrigerant, stores the liquid-phase refrigerant, and sucks the gas-phase refrigerant into the compressor 6. The accumulator 10 also plays a role of causing the compressor 6 to suck the oil dissolved in the liquid refrigerant accumulated on the tank bottom side.

(accumulator)
The refrigerant 44 shown in FIG. 2 is a refrigerant that has flowed out of the evaporator 3 and is in a gas-liquid two-phase state. The refrigerant 44 that has passed through the refrigerant inlet pipe 41 connected from the evaporator 3 flows into the internal space of the tank 45 from the inflow port 46 provided in the tank 45. In the internal space of the tank 45, the stored liquid-phase refrigerant 47 and vapor-phase refrigerant 48 exist. The gas-liquid two-phase refrigerant 44 is separated into a gas-phase refrigerant and a liquid refrigerant by the gas-liquid separator 52. The vapor-phase refrigerant 48 is sent to the compressor 6 through a refrigerant outlet pipe 42 connected to an outlet 49 provided in the tank 45.

(Bypass passage)
The bypass passage 43 connects the refrigerant inlet pipe 41 and the refrigerant outlet pipe 42 for flowing the refrigerant from the accumulator 10 outside the accumulator 10, and short-circuits the refrigerant so that the refrigerant can flow. The bypass passage 43 is provided with a valve device 40 for opening and closing the bypass passage 43. The valve device 40 “allows” or “blocks” the flow of the refrigerant in the bypass passage 43. Here, the valve device 40 is preferably an on-off valve as shown in FIG. The flow of the refrigerant in the bypass passage 43 can be controlled with a simple structure. That is, when the opening/closing valve is opened, the flow of the refrigerant in the bypass passage is “permitted”. At this time, since the refrigerant inlet pipe 41 and the refrigerant outlet pipe 42 are not closed, the refrigerant can flow into the accumulator 10, but the air flow resistance in the bypass passage 43 becomes smaller than that in the accumulator 10, so that the bypass is bypassed. The flow in the passage 43 becomes dominant. At this time, the pressure in the bypass passage 43 and the pressure in the accumulator 10 are naturally approximated. On the other hand, when the on-off valve is closed, the flow of the refrigerant in the bypass passage is “blocked” and the refrigerant flows into the accumulator 10.

The valve device 40 is preferably a three-way valve arranged at the confluence of the bypass passage 43 and the refrigerant outlet pipe 40 as shown in FIG. The flow of the refrigerant in the bypass passage 43 can be controlled with a simple structure. That is, when the bypass passage is opened and the refrigerant outlet pipe 42 is closed in the three-way valve, the flow of the refrigerant in the bypass passage is “permitted”. At this time, since the refrigerant outlet pipe 42 is closed, the refrigerant does not flow into the accumulator 10. However, since the refrigerant inlet pipe 41 is not closed, the pressure in the bypass passage 43 and the pressure in the accumulator 10 are naturally approximated. On the other hand, when the bypass passage is closed and the refrigerant outlet pipe 42 is opened in the three-way valve, the flow of the refrigerant in the bypass passage is “blocked” and the refrigerant flows into the accumulator 10.

The valve device 40, as the on-off valve shown in FIG. 2 or the three-way valve shown in FIG. 3, is capable of “permitting” or “blocking” the flow of the refrigerant in the bypass passage 43, as described above. , Has the same effect.

(Refrigerant temperature detection means)
As shown in FIG. 2, it is preferable that the vehicle air conditioner according to the present embodiment further include a refrigerant temperature detecting means 50 capable of detecting the temperature of the liquid-phase refrigerant 47 inside the accumulator 10. Here, it is preferable that the temperature sensor portion of the coolant temperature detecting means 50 is disposed below the center of the internal space of the accumulator 10 or on the outer bottom surface of the accumulator 10. By disposing the temperature sensor unit in such a place, the temperature of the liquid-phase refrigerant 47 can be accurately detected. In FIG. 2, the temperature sensor portion of the coolant temperature detecting means 50 is arranged on the outer bottom surface of the accumulator 10. It is possible to more accurately estimate the valve closing timing of the valve device, and as a result, it is possible to more accurately suppress the occurrence of bumping. Further, when the temperature sensor part of the refrigerant temperature detecting means 50 is arranged below the center of the internal space of the accumulator 10, the amount of the liquid refrigerant 47 accumulated in the accumulator 10 fluctuates, although it may fluctuate. Even in this case, the liquid temperature of the liquid refrigerant 47 can be accurately measured.

(External temperature detection means)
The vehicle air conditioner according to the present embodiment preferably further includes a vehicle outside temperature detecting means 51, as shown in FIG. It should be noted that it is preferable to further include the vehicle outside temperature detecting means 51 also in the configurations shown in FIGS. 2 and 3. Immediately after the compressor 6 is started, the refrigerant boils inside the accumulator 10 and the abnormal noise is higher than the condition (for example, 35° C.) where the temperature outside the vehicle is relatively high, although it depends on the state of the rotation speed of the compressor. The conditions (for example, 20° C.) and lower conditions (for example, 10° C.) are more likely to occur, and the timing of the opening/closing operation of the valve device 40 can be accurately adjusted by grasping the temperature outside the vehicle.

(Control device)
The control device 23 controls “permit” or “block” the flow of the refrigerant in the bypass passage 43 by the valve device 40. For example, it controls switching between opening and closing of the on-off valve. In addition, the switching of the bypass passage 43 and the refrigerant outlet pipe 42 closed in the three-way valve or the bypass passage 43 and the refrigerant outlet pipe 42 opened is controlled. Further, the operation of the compressor 6 is controlled. For example, when the compressor 6 is an electric compressor, the control device 23 specifies the rotation speed of the electric compressor, and the electric compressor is driven to reach the specified rotation speed. In addition to controlling the valve device 40 and the compressor 6, the control device 23 may control other devices. Further, the control device 23 may obtain information from various sensors, for example, the temperature information of the liquid phase refrigerant inside the accumulator from the refrigerant temperature detecting means 50. Further, the control device 23 may obtain the vehicle exterior temperature information from the vehicle exterior temperature detecting means 51.

(Modification of refrigeration cycle)
In the vehicle air conditioner according to the present embodiment, the bypass passage 43 and the valve device 40 are applied to not only a simple refrigeration cycle for cooling (first example of refrigeration cycle) but also a refrigeration cycle capable of dehumidifying and heating. Good. For example, you may apply to the vehicle air conditioner disclosed by the international publication 2013/035130. Specifically, it can be applied to the device described in FIG. 1, FIG. 5, FIG. 6 or FIG.

(Second example of refrigeration cycle)
FIG. 5 shows a schematic diagram of a second example of the configuration of the refrigeration cycle in the vehicle air conditioner according to the present embodiment. The second example of the configuration of the refrigeration cycle is an example in which the bypass passage 43 and the valve device 40 are applied to the device shown in FIG. 1 of WO 2013/035130. The open/close valve 17 in the drawing of the publication is the same as the open/close valve 17 in the drawings of the present application.

(Third example of refrigeration cycle)
FIG. 6 shows a schematic diagram of a third example of the configuration of the refrigeration cycle in the vehicle air conditioner according to the present embodiment. The third example of the configuration of the refrigeration cycle is an example in which the bypass passage 43 and the valve device 40 are applied to the device shown in FIG. 5 of WO 2013/035130.

(Fourth example of refrigeration cycle)
FIG. 7 shows a schematic diagram of a fourth example of the configuration of the refrigeration cycle in the vehicle air conditioner according to the present embodiment. The fourth example of the configuration of the refrigeration cycle is an example in which the bypass passage 43 and the valve device 40 are applied to the device shown in FIG. 6 of WO 2013/035130.

(Fourth example of refrigeration cycle)
FIG. 8 shows a schematic diagram of a fifth example of the configuration of the refrigeration cycle in the vehicle air conditioner according to the present embodiment. The fifth example of the configuration of the refrigeration cycle is an example in which the bypass passage 43 and the valve device 40 are applied to the device shown in FIG. 7 of WO 2013/035130.

Next, the vehicle air conditioner according to the present embodiment will be described in more detail with reference to FIGS. 2, 9 and 10. The vehicle air conditioner according to the present embodiment further includes a refrigerant temperature detecting means 50 capable of detecting the temperature of the liquid phase refrigerant inside the accumulator, the compressor 6 is an electric type, and the control device 23 is a compressor. The machine 6 is started at the designated rotation speed, and the flow of the refrigerant in the bypass passage 43 is allowed by the valve device 40 (the state shown in FIG. 9). Then, the compressor 6 is designated. The estimated superheat degree Test of the vapor phase refrigerant 48 inside the accumulator 10 when the flow of the refrigerant in the bypass passage 43 is cut off is calculated from the rotational speed and the temperature information obtained from the refrigerant temperature detection means 50, and the estimated superheat degree is calculated. Test and a predetermined threshold superheat degree Tdef are compared, and when the estimated superheat degree Test falls below the threshold superheat degree Tdef, the flow of the refrigerant in the bypass passage 43 is shut off by the valve device 40 (in the state shown in FIG. 10). It is preferable. It is possible to estimate the valve closing timing of the valve device and accurately suppress the occurrence of bumping. Specifically, it is as follows. FIG. 11 shows a specific control flow chart of the control device 23. Since the compressor 6 is an electric type, it is possible to control the compressor 6 at a rotation speed designated by the control device 23. Then, it is possible to estimate the pressure of the gas-phase refrigerant 48 in the accumulator 10 after the flow of the refrigerant in the bypass passage 43 is blocked (hereinafter referred to as the estimated pressure) from the rotation speed of the compressor 6. The estimated superheat degree Test is calculated from the estimated pressure and the temperature information obtained from the refrigerant temperature detection means 50. Here, the formula for calculating the degree of superheat is, as a premise, a formula for estimating that bumping will not occur when the valve device 40 that is open is closed. This degree of superheat is defined as "estimated degree of superheat Test" when the valve is closed. The larger the suction refrigerant amount Vs of the compressor 6, the lower the gas phase pressure Pvs of the internal space of the accumulator 10 when the valve device 40 is closed. Further, the higher the temperature Tliq of the liquid refrigerant is, the higher the boiling point temperature is, and the larger the evaporation amount Veva of the refrigerant from the liquid refrigerant is. Therefore, it cannot be said that the higher the temperature of the liquid refrigerant is, the easier the boiling is. Based on these, the estimated superheat degree Test is calculated by the following equation (Equation 1). Here, α, β, and γ are coefficients.
(Equation 1) Test1=α·Tliq − (β·Veva×γ·Pvs)
Further, as the outside air load (outside air temperature) Tout is higher, the amount of the refrigerant stored inside the accumulator decreases and the gas phase region increases, so that even if the refrigerant is sucked by the compressor 6, the amount of decrease in the gas phase pressure Pvs. Is moderate, and even if the refrigerant evaporation amount Veva is a constant amount, the increase in the vapor phase pressure Pvs is also moderate. Therefore, the estimated superheat degree Test can be calculated with higher accuracy by reflecting the outside air temperature Tout in Formula 1. Specifically, it is calculated as in the following equation (Equation 2).
(Equation 2) Test2 =
α·Tliq − (β·Veva×γ·Pvs/Tout)
Then, the estimated superheat degree calculated by the equations 1 and 2 is compared with the threshold superheat degree, and when the estimated superheat degree Test falls below the threshold superheat degree Tdef, the valve device 40 is controlled to be closed. The threshold superheat degree Tdef is preferably set to be lower than the boiling temperature of the liquid refrigerant by a predetermined temperature. As the threshold superheat degree Tdef is set lower with respect to the boiling temperature, the effect of preventing bumping becomes higher. Here, the predetermined temperature is preferably a predetermined temperature selected from the range of 1°C to 6°C, and more preferably a predetermined temperature selected from the range of 2°C to 5°C. The threshold superheat degree Tdef is preferably set, for example, 2° C. lower than the boiling temperature and more preferably 5° C. lower than the boiling temperature.

Next, refer to FIG. 3, FIG. 12 and FIG. This form is an example in which the on-off valve of the form shown in FIGS. 2, 9 and 10 is changed to a three-way valve. FIG. 12 shows a state in which the flow of the refrigerant in the bypass passage 43 is allowed by the valve device 40. FIG. 13 shows a state in which the flow of the refrigerant in the bypass passage 43 is blocked by the valve device 40. The control of the control flow chart shown in FIG. 11 can be applied to the configurations shown in FIGS. 3, 12, and 13.

Next, with reference to FIG. 2, FIG. 9 and FIG. 10, an example of performing another control of the vehicle air conditioner according to the present embodiment will be described. In the vehicle air conditioner according to the present invention, the control device 23 allows the flow of the refrigerant in the bypass passage 43 by the valve device 40 when the compressor 6 is activated (the state shown in FIG. 9). ) Then, after a predetermined time has passed, it is preferable that the flow of the refrigerant in the bypass passage 43 is blocked by the valve device 40 (the state shown in FIG. 10). The control device 23 has a timer function. Even without providing the coolant temperature detection means, it is possible to accurately suppress the occurrence of bumping with a simple configuration. FIG. 14 shows a specific control flow chart of the control device 23. The predetermined time is, for example, a predetermined time to be selected from the range of 90 to 180 seconds.

Next, the vehicle air conditioner according to the present embodiment will be described with reference to FIG. In the vehicle air conditioner according to the present embodiment, the vehicle outside temperature detecting means 51 is further provided, and the control measure 23 is configured such that, when the compressor 6 is started, the outside temperature obtained from the vehicle outside temperature detecting means 51 is less than the predetermined temperature. It is preferable that the flow of the refrigerant in the bypass passage 43 is allowed by the valve device 40 at a certain time, and the flow of the refrigerant in the bypass passage 43 is blocked by the valve device 40 when the temperature outside the vehicle is equal to or higher than a predetermined temperature. By using the vehicle exterior temperature detecting means 51, it is possible to accurately suppress the occurrence of bumping with a simple configuration. FIG. 15 shows a specific control flow chart of the control device 23. The predetermined temperature of the vehicle exterior temperature is a predetermined temperature that is selected from a range of 5° C. or less, for example.

The vehicle air conditioner according to the present embodiment can avoid an excessively depressurized state of the internal space in the accumulator 10 in any form. With this, it is possible to suppress the occurrence of bumping of the liquid refrigerant, and thus to suppress the generation of abnormal noise from the accumulator due to the bumping phenomenon.

3 evaporator 4 outdoor heat exchanger 6 compressor 10 accumulator 12 expansion device 17 on-off valve 23 control device 40 valve device 41 refrigerant inlet pipe 42 refrigerant outlet pipe 43 bypass passage 44 refrigerant 45 tank 46 inlet 47 liquid phase refrigerant 48 gas phase Refrigerant 49 Outlet 50 Refrigerant temperature detection means 51 Vehicle temperature detection means 52 Gas-liquid separator 63 Pulley 80 Refrigeration cycle

Claims (7)

At least a compressor (6), an outdoor heat exchanger (4), an expansion device (12), an evaporator (3) and an accumulator (10), and a refrigeration cycle (80) connected by piping in this order, and a refrigeration cycle. A refrigerant inlet pipe (41) for flowing a refrigerant circulating through the cycle into an accumulator and a refrigerant outlet pipe (42) for flowing out the refrigerant from the accumulator are connected outside the accumulator, and the refrigerant is short-circuited to enable circulation. A bypass passage (43),
A valve device (40) having an opening/closing function provided in the bypass passage,
At least a control device (23) for controlling the compressor and the valve device,
An air conditioner for a vehicle, comprising: The vehicle air conditioner according to claim 1, wherein the valve device is an opening/closing valve that allows or blocks the flow of the refrigerant in the bypass passage. The vehicle air conditioner according to claim 1, wherein the valve device is a three-way valve disposed at a confluence of the bypass passage and the refrigerant outlet pipe. Further comprising a refrigerant temperature detecting means (50) capable of detecting the temperature of the liquid phase refrigerant inside the accumulator,
The compressor is electric,
The control device is
The compressor is started at a designated rotation speed, and the valve device allows the flow of the refrigerant in the bypass passage,
Then, from the rotational speed designated by the compressor and the temperature information obtained from the refrigerant temperature detection means, the gas-phase refrigerant (48) inside the accumulator when the flow of the refrigerant in the bypass passage is shut off. Calculate the estimated superheat degree Test,
Comparing the estimated superheat degree Test and a predetermined threshold superheat degree Tdef, and when the estimated superheat degree Test falls below the threshold superheat degree Tdef, the flow of the refrigerant in the bypass passage is shut off by the valve device. The vehicle air conditioner according to any one of claims 1 to 3. The vehicle air conditioner according to claim 4, wherein the temperature sensor portion of the refrigerant temperature detecting means is arranged below the center of the internal space of the accumulator or on the outer bottom surface of the accumulator. The control device is in a state in which the flow of the refrigerant in the bypass passage is allowed by the valve device at the time of starting the compressor, and then, after a predetermined time has elapsed, the refrigerant in the bypass passage by the valve device. The air conditioner for a vehicle according to any one of claims 1 to 3, wherein the flow of the air is cut off. Further having a vehicle outside temperature detecting means (51),
The control measure, when starting the compressor, a state in which the flow of the refrigerant in the bypass passage is allowed by the valve device when the vehicle exterior temperature obtained from the vehicle exterior temperature detection means is lower than a predetermined temperature, The vehicle air conditioner according to any one of claims 1 to 3, wherein the valve device shuts off the flow of the refrigerant in the bypass passage when the vehicle exterior temperature is equal to or higher than a predetermined temperature.

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