JP3993760B2 - Air conditioner for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle air conditioner.
[0002]
[Prior art]
Conventionally, as a vehicle air conditioner, there is one in which an in-vehicle heat exchanger provided in the middle of a refrigeration cycle can be used not only for cooling air passing but also for heating by reversing the circulation direction of the refrigerant. According to this, the air blown into the vehicle can be heated not only by the heater core through which the engine coolant flows, but also by the vehicle interior heat exchanger.
[0003]
[Problems to be solved by the invention]
However, in the conventional vehicle air conditioner, when heating by the vehicle interior heat exchanger is enabled only when the outside air temperature is very low, heating in the vehicle may not be started quickly.
[0004]
Then, this invention makes it a subject to provide the vehicle air conditioner which can raise ventilation temperature rapidly even just after the heating operation start.
[0005]
[Means for Solving the Problems]
As a means for solving the above problems, the present invention provides:
In a vehicle air conditioner equipped with a refrigeration cycle that circulates the refrigerant discharged from the compressor back to the compressor via the vehicle exterior heat exchanger, pressure control valve, vehicle interior heat exchanger, and accumulator,
A hot water heat exchanger connected between the in-vehicle heat exchanger and the accumulator of the refrigeration cycle and exchanging heat between the refrigerant and the engine coolant;
A bypass flow path for guiding the refrigerant from the compressor to the vehicle interior heat exchanger, bypassing the vehicle exterior heat exchanger;
An auxiliary bypass flow path provided with a pressure reducing valve for bypassing the refrigerant from the compressor and bypassing the vehicle exterior heat exchanger and the vehicle interior heat exchanger to the hot water heat exchanger;
Channel switching means for switching the channel to the refrigeration cycle, the bypass channel , or the auxiliary bypass channel ;
From the start of heating operation until the heating condition that allows air to be blown into the vehicle at the desired air blowing temperature by the vehicle interior heat exchanger is allowed to flow through the engine cooling water to the hot water heat exchanger, and the flow path switching means, By switching the flow path to a bypass flow path, causing the warm water heat exchanger to flow engine cooling water, starting heating by the vehicle interior heat exchanger, and switching the flow path to the bypass flow path, Control means for increasing the amount of refrigerant bypassing the vehicle interior heat exchanger by opening the pressure reducing valve so that the refrigerant can also flow into the auxiliary bypass flow path when the heating condition is not satisfied ;
Is provided.
[0006]
With this configuration, it is possible not only to switch to the bypass flow path by the flow path switching means and to heat by the vehicle interior heat exchanger, but also to warm the refrigerant by the engine cooling water. Therefore, even before the engine coolant sufficiently rises, heating by the vehicle interior heat exchanger can be started quickly and effectively, and the temperature of the air blown into the vehicle can be immediately raised. In addition, it is possible to start heating by the vehicle interior heat exchanger with the heating capacity stabilized.
[0011]
When the control means controls the flow rate of engine cooling water in the hot water heat exchanger based on the target heating capacity of the vehicle interior heat exchanger determined from the difference between the set temperature and the inside air temperature, the refrigerant is It is preferable in that the pressure can be prevented from rising more than necessary and the power consumption can be reduced.
[0013]
Increasing the drive rotational speed of the compressor at the beginning of the heating operation is preferable in that it is possible to further increase the temperature of the blown air into the vehicle.
[0014]
By making the compressor electric, it is preferable that the interior heating can be continued if the compressor can be driven even when the engine is stopped.
[0015]
An electric pump that circulates engine cooling water between the engine and the hot water heat exchanger is provided, and the electric pump is driven even when the engine is stopped to enable circulation of the engine cooling water. It is preferable in that the remaining heat of the engine can be supplied to the refrigerant through the hot water heat exchanger, and further, heating in the vehicle can be continued.
[0016]
The control means is preferable in that the electric pump can be driven and controlled based on the refrigerant pressure discharged from the compressor, the electric pump can be driven only when necessary, and the power consumption can be suppressed.
[0017]
What is necessary is just to connect the heater core which heats the air after passing the said vehicle interior heat exchanger in the middle of the warm water flow path which connects the said engine and the said warm water heat exchanger.
[0018]
It is preferable that the engine coolant flowing through the hot water heat exchanger and the refrigerant are in a counterflow.
[0019]
Note that CO ₂ can be used as the refrigerant.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to the accompanying drawings.
[0021]
FIG. 1 shows a vehicle air conditioner according to this embodiment. In this vehicle air conditioner, a blower 2, a vehicle interior heat exchanger 3, a mix damper 4, a heater core 5, and an auxiliary heater 6 are sequentially arranged from the upstream side in the air conditioning unit 1 in the front part of the vehicle. .
[0022]
The blower 2 rotates by driving the blower motor 7 and guides the inside air or outside air selected by the inside / outside air switching damper 8 into the air conditioning unit 1.
[0023]
The vehicle interior heat exchanger 3 constitutes one device of the refrigeration cycle C. In the refrigeration cycle C, the refrigerant discharged from the compressor 9 passes through the outside heat exchanger 10, the pressure control valve 11, the check valve 12, the inside heat exchanger 3, the hot water heat exchanger 13, and the accumulator 14. And return to the compressor 9 for circulation. The refrigeration cycle C is connected to a bypass passage B1 that bypasses the outside heat exchanger 10, the pressure control valve 11, and the check valve 12, and the refrigerant discharged from the compressor 9 by switching the first three-way valve 15 is connected. However, it can flow directly into the vehicle interior heat exchanger 3. Further, an auxiliary bypass path B2 that bypasses the vehicle interior heat exchanger 3 is connected to the bypass path B1. A pressure reducing valve 16 is connected in the middle of the auxiliary bypass passage B2. The opening of the pressure reducing valve 16 can be adjusted based on a control signal from the control device 25 described later, and adjusts the refrigerant flow rate that bypasses the vehicle interior heat exchanger 3. Note that CO ₂ is used as the refrigerant.
[0024]
The power of the engine 17 is transmitted to the compressor 9 via a clutch (not shown). The drive rotation speed of the compressor 9 can be switched to a plurality of stages (may be stepless) by switching the clutch. The drive rotational speed of the compressor 9 is normally set to a value that allows the refrigerant to flow through the vehicle exterior heat exchanger 10 at supercritical pressure. The vehicle exterior heat exchanger 10 is disposed in the front portion of the vehicle and radiates the refrigerant to the outside air. The pressure control valve 11 depressurizes the refrigerant and supplies it to the in-vehicle heat exchanger 3 in a state where it is easy to vaporize, and plays a role of adjusting the pressure as described later. The vehicle interior heat exchanger 3 absorbs heat from the inside air or the outside air passing outside by the refrigerant flowing inside. The temperature of the refrigerant flowing out of the vehicle interior heat exchanger 3 is detected by a temperature sensor 18, and the pressure of the refrigerant discharged from the compressor 9 is detected by a pressure sensor 19. The accumulator 14 is provided in order to return the refrigerant to the compressor 9 in a state in which the refrigerant has been reliably vaporized.
[0025]
The heater core 5 is disposed in one flow path divided by the mix damper 4 and constitutes one device of the heating cycle H. In the heating cycle H, the engine coolant is circulated in a separate circuit from the radiator 21 disposed in the front portion of the vehicle by switching the second three-way valve 20 and is radiated by the heater core 5 in the middle of the circuit. Further, the warm water heat exchanger 13 is provided in the middle of the heating cycle H, and the third three-way valve 22 is switched between the refrigerant flowing in the refrigeration cycle C and the engine coolant flowing in the heating cycle H. It is possible to perform heat exchange. In the hot water heat exchanger 13, the refrigerant and the engine cooling water are configured to face each other to improve the heat exchange performance. In the middle of the heating cycle H, an electric pump 23 and a water temperature detection sensor 24 are provided. The electric pump 23 can be driven by power supplied from the battery when the engine 17 is stopped. The water temperature detection sensor 24 detects the temperature of the engine cooling water. The detected temperature is used for determining whether to drive the electric pump 23 and supply engine cooling water to the hot water heat exchanger 13.
[0026]
The auxiliary heater 6 assists the heating of the heater core 5 with electric power supplied from a battery (not shown) when the engine 17 is stopped.
[0027]
The opening degree of the pressure control valve 11 is controlled by the control device 25 based on the driving rotational speeds of the blower motor 7 and the compressor 9, the rotational position of the inside / outside air switching damper 8, and the like. Based on various conditions inside and outside the vehicle obtained from the inside air sensor 26, outside air sensor 27, solar radiation sensor 28, etc., the control device 25 drives the rotational speed of the blower motor 7 and the compressor 9, the opening degree of the mix damper 4, the first three-way The switching of the valve 15 and the second three-way valve 20, the opening degree of the pressure reducing valve 16, and the like are controlled. The control device 25 controls the third three-way valve 22 and the motor operated valve 23 based on the temperature detected by the water temperature sensor 24.
[0028]
Next, the operation of the vehicle air conditioner having the above configuration will be described with reference to the flowchart of FIG. In the following description, only the case of performing the heating operation which is a characteristic part of the present invention will be described.
[0029]
First, various conditions inside and outside the vehicle, such as the inside air temperature detected by the inside air sensor 26, the outside air temperature detected by the outside air sensor 27, the amount of solar radiation detected by the solar radiation sensor 28, and the set temperature in the vehicle, are read (step S1). Based on various conditions inside and outside the vehicle, the rotational speed of the compressor 9 and the opening degree of the mix damper 4 are determined (step S2). In this case, in the refrigeration cycle C, the refrigerant returns from the compressor 9 to the compressor 9 via the vehicle exterior heat exchanger 10, the pressure control valve 11, the vehicle interior heat exchanger 3, the hot water heat exchanger 13, and the accumulator 14. The first three-way valve 15 is switched so as to circulate in the mode.
[0030]
Here, the engine cooling water temperature _TE is read based on the detection signal from the water temperature detection sensor 24 (step S3). Then, the read temperature T _E of the engine cooling water to determine low or not than the set temperature T _S (step S4). Even if the engine coolant at that temperature is passed through the heater core 5, a value at which a desired heating capacity cannot be obtained is used as the set temperature T _S.
[0031]
If the temperature T _E of the engine cooling water is set temperature T _S or more, since it is possible to exhibit sufficient heating capacity by heating of the heater core 5 performs normal heating only by the heater core 5. The first three-way valve 15 is switched so that the refrigerant circulates in the cooling mode, and dehumidification is performed by the vehicle interior heat exchanger 3. However, if the step of temperature T _E of the engine cooling water is not much increased from the set temperature T _S, as the temperature of the air passing through the dehumidifying operation by the vehicle-side heat exchanger 3 decreases, heating capacity of the heater core 5 In such a case, the drive of the compressor 9 is stopped.
[0032]
On the other hand, if the temperature T _E of the engine coolant is lower than the set temperature T _S, the engine cooling water by switching the second three-way valve 20 from being radiated by the radiator 21 (step S5). In addition, since heating by the heater core 5 is insufficient, the first three-way valve 15 is set so that the refrigerant discharged from the compressor 9 bypasses the vehicle exterior heat exchanger 10 and flows directly into the vehicle interior heat exchanger 3. Switching (step S6). At this time, the pressure P _V of the refrigerant to be detected to determine whether lower than the set pressure P _S by the pressure sensor 19 (step S7). The set pressure P _S, the refrigerant is allowed to flow into the vehicle-side heat exchanger 3 at this pressure below the dissipating the air passing through the air conditioning unit 1, the proportion of the liquid phase is too many vehicle-side heat exchanger Use a value that cannot raise the temperature sufficiently at 3.
[0033]
If the pressure P _V of the refrigerant detected by the pressure sensor 19 is the set pressure P _S above, pressure reducing valve 16 is a closed state (opening 0), flowing in the air conditioning unit 1 from the refrigerant in the interior side heat exchanger 3 The air to be radiated is radiated (step S8).
[0034]
On the other hand, when the pressure P _V of the refrigerant detected by the pressure sensor 19 is less than the set pressure P _S, the heating performance of the vehicle-side heat exchanger 3 is determined that the state can not be sufficiently exerted, the pressure reducing valve The opening of 16 is increased (step S9). In this case, opening of the pressure reducing valve 16 may be changed stepwise according to a difference in pressure P _V of the refrigerant may be a one of the opening and closing. Thereby, the refrigerant | coolant flow volume which bypasses the vehicle interior heat exchanger 3 increases, and it becomes possible to fully exhibit the heating performance of the vehicle interior heat exchanger 3 by making a refrigerant | coolant into a high temperature and high pressure state at an early stage.
[0035]
Thereafter, since the heat exchange efficiency of the vehicle interior heat exchanger 3 (between refrigerant and air) is known, the target air temperature and the target air volume are calculated based on the temperature difference between the set temperature read in step S1 and the inside air temperature. (Step S10). And since the target condensation capacity | capacitance (target condensation pressure or target condensation temperature) by the vehicle interior side heat exchanger 3 is determined based on the calculated target ventilation temperature and target ventilation volume, warm water heat exchange is performed so that this target condensation capacity can be obtained. The amount of engine cooling water flowing into the vessel 13 is adjusted by controlling the drive speed of the electric pump 23 (step S11). As a result, the hot water heat exchanger 13 absorbs heat from the engine coolant to the refrigerant, and the subsequent heating in the vehicle interior heat exchanger 3 can be appropriately performed.
[0036]
In this way, since the refrigerant that has been brought into a high temperature and high pressure state by the compressor 9 can be caused to flow into the vehicle interior heat exchanger 3, the lack of heating capacity of the heater core 5 can be compensated by the vehicle interior heat exchanger 3. it can. Therefore, even before the temperature of the engine coolant rises, vehicle interior heating at a desired air blowing temperature is realized at an early stage.
[0037]
When the refrigerant flows while bypassing the vehicle interior heat exchanger 3, the auxiliary heating by the vehicle interior heat exchanger 3 can no longer be performed. Therefore, the auxiliary heater 6 is energized from the battery, and the heater core 5 is heated by the auxiliary heater 6. The lack of capability is compensated (step S12).
[0038]
As described above, according to the vehicle air conditioner according to the above-described embodiment, the vehicle interior heat exchanger 3 is used as auxiliary heating even if the temperature of the engine coolant is not sufficiently increased immediately after the engine 17 is started. Can be used. Moreover, not only the temperature of the refrigerant is raised by the hot water heat exchanger 13, but also the inside heat exchanger 3 is bypassed when the refrigerant is not sufficiently heated. In addition, while the vehicle interior heat exchanger 3 cannot be used, the auxiliary heater 6 can be used.
[0039]
In the above embodiment, as the heating conditions for changing the switching direction of the first three-way valve 15, but using the pressure P _V of the refrigerant discharged from the compressor 9, the refrigerant discharged from the compressor 9 temperature, The temperature of the engine cooling water on the inlet side of the hot water heat exchanger 13 or the outside air temperature may be used. In short, any parameter can be used as a heating condition as long as it can be determined whether or not sufficient heating capacity can be obtained by the vehicle interior heat exchanger 3. The use of the outside air temperature for the heating condition is limited to the case where the outside air introduction mode is selected.
[0040]
In the above-described embodiment, the compressor 9 is driven based on the power of the engine 17. However, the compressor 9 may be electrically driven by power supplied from the battery. According to this, even when the engine 17 is stopped, the refrigerant is circulated and air conditioning by the vehicle interior heat exchanger 3 becomes possible.
[0041]
In the embodiment, the vehicle interior heat exchanger 3 is configured to perform only one of cooling and heating. For example, as shown in FIG. 3, the air flow in the air conditioning unit is increased. You may make it comprise with the two heat exchange parts 29a and 29b divided | segmented in the downstream direction. An expansion valve 30 and an on-off valve 31 are connected in parallel between the downstream heat exchange unit 29a and the upstream heat exchange unit 29b. When the vehicle interior heat exchanger 3 is used for cooling as usual, the open / close valve 31 is fully opened, and the air passing through the heat exchange sections 29a and 29b on both the upstream and downstream sides can be cooled. Further, when the vehicle interior heat exchanger 3 is used for heating, if the opening / closing valve 31 is fully opened, the air passing through either the upstream or downstream heat exchange section 29a, 29b can be heated. Further, the on-off valve 31 can be fully closed, the air passing through the upstream heat exchange unit 29b can be dehumidified, and the air after dehumidification can be heated by the downstream heat exchange unit 29a.
[0042]
【The invention's effect】
As is clear from the above description, according to the present invention, heating by the vehicle interior heat exchanger is performed by switching the flow path to the bypass flow path by the flow path switching means and flowing the engine cooling water to the hot water heat exchanger. Thus, even immediately after the start of the heating operation, the temperature of the air blown into the vehicle can be immediately increased, and the interior of the vehicle can be heated quickly.
[Brief description of the drawings]
FIG. 1 is a schematic view of a vehicle air conditioner according to an embodiment.
FIG. 2 is a flowchart showing the contents of air conditioning control by the control device of FIG. 1;
FIG. 3 is a schematic view showing another example that can be employed in the vehicle interior heat exchanger of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Air-conditioning unit 2 ... Blower 3 ... Car inside heat exchanger 4 ... Mix damper 5 ... Heater core 6 ... Auxiliary heater 7 ... Blower motor 9 ... Compressor 10 ... Car outside heat exchanger 11 ... Pressure control valve 13 ... Hot water heat exchanger 15 ... first three-way valve 16 ... pressure reducing valve 17 ... engine 18 ... temperature sensor 19 ... pressure sensor 20 ... second three-way valve 22 ... third three-way valve 23 ... electric pump 25 ... control device

Claims (9)

In a vehicle air conditioner equipped with a refrigeration cycle that circulates refrigerant discharged from the compressor back to the compressor via the vehicle exterior heat exchanger, pressure control valve, vehicle interior heat exchanger, and accumulator,
A hot water heat exchanger connected between the in-vehicle heat exchanger and the accumulator of the refrigeration cycle and exchanging heat between the refrigerant and the engine coolant;
A bypass flow path for guiding the refrigerant from the compressor to the vehicle interior heat exchanger by bypassing the vehicle exterior heat exchanger;
An auxiliary bypass flow path having a pressure reducing valve that bypasses the vehicle-side heat exchanger and the vehicle-side heat exchanger and guides the refrigerant from the compressor to the hot water heat exchanger;
Channel switching means for switching the channel to the refrigeration cycle, the bypass channel , or the auxiliary bypass channel ;
From the start of the heating operation until the heating condition that allows air to be blown into the vehicle at a desired air blowing temperature by the vehicle interior heat exchanger is allowed to flow through the engine cooling water to the hot water heat exchanger, and by the flow path switching means, By switching the flow path to the bypass flow path, causing the warm water heat exchanger to flow engine cooling water, starting heating by the vehicle interior heat exchanger, and switching the flow path to the bypass flow path, Control means for increasing the amount of refrigerant bypassing the vehicle interior heat exchanger by opening a pressure reducing valve so that the refrigerant can also flow into the auxiliary bypass flow path when the heating condition is not satisfied ;
A vehicle air conditioner characterized by comprising:   The control means controls the flow rate of engine cooling water in the hot water heat exchanger based on a target heating capacity of the vehicle interior heat exchanger determined from a difference between a set temperature and an inside air temperature. The vehicle air conditioner according to claim 1.   The vehicle air conditioner according to claim 1 or 2, wherein the drive rotational speed of the compressor is increased at the beginning of heating operation.   The vehicle air conditioner according to any one of claims 1 to 3, wherein the compressor is electrically driven so that the compressor can be driven even when the engine is stopped.   An electric pump that circulates engine cooling water between the engine and the hot water heat exchanger is provided, and the engine cooling water can be circulated by driving the electric pump even when the engine is stopped. The vehicle air conditioner according to claim 3 or 4, wherein the vehicle air conditioner is provided.   6. The vehicle air conditioner according to claim 5, wherein the control means drives and controls the electric pump based on a refrigerant pressure discharged from the compressor.   The heater core which heats the air after passing the said vehicle interior heat exchanger was connected to the middle of the hot water flow path connecting the engine and the hot water heat exchanger. The vehicle air conditioner according to Item 1.   The vehicle air conditioner according to any one of claims 1 to 7, wherein the engine cooling water flowing through the hot water heat exchanger and the refrigerant are opposed to each other.   The refrigerant is CO ₂ The vehicle air conditioner according to any one of claims 1 to 8, wherein

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