JP3977629B2 - 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 comprising a compressor, a vehicle exterior heat exchanger, a pressure control valve, a vehicle interior heat exchanger, and an accumulator,
The vehicle interior heat exchanger is composed of a plurality of heat exchange parts by dividing the air flow in the air conditioning unit in the upstream and downstream direction, and an expansion valve is connected in the middle of the pipe connecting the heat exchange parts,
Cooling mode in which refrigerant discharged from the compressor circulates in the order of the vehicle exterior heat exchanger, pressure control valve, vehicle interior heat exchanger, and accumulator, or vehicle interior heat exchanger, pressure control valve, vehicle exterior heat exchange A four-way valve that switches the flow path to either one of the heating mode that circulates in the order of the condenser and the accumulator,
When the flow path is switched to the heating mode by the four-way valve, a bypass flow path in which the refrigerant bypasses the outside heat exchanger,
A hot water heat exchanger that is disposed in the middle of the bypass flow path and exchanges heat between the refrigerant and the engine coolant;
An auxiliary bypass passage through which the refrigerant from the compressor is guided to the hot water heat exchanger by bypassing the vehicle exterior heat exchanger and the vehicle interior heat exchanger;
In addition to the refrigeration cycle or the bypass channel, channel switching means for switching the channel to the auxiliary bypass channel;
When the four-way valve is switched and the refrigerant is circulated in the heating mode, the flow path switching means switches the flow path to the bypass flow path, and causes the engine cooling water to flow to the hot water heat exchanger. Control means for starting heating by the inner heat exchanger;
Provided,
The control means switches the flow path from the start of the heating operation by switching the four-way valve to drive the compressor until the heating condition that enables normal heating only by the vehicle interior heat exchanger is satisfied. The channel is switched to the auxiliary bypass channel by means .
[0008]
When an open / close valve is connected in parallel to the expansion valve, it is possible to select whether the total heat exchange part of the vehicle interior heat exchanger is used for heating or a part thereof is used for dehumidification. preferable.
[0010]
The control means determines a target condensation capacity by the vehicle interior heat exchanger based on a target air temperature and a target air volume calculated from a difference between the set temperature and the inside air temperature, and cools the engine in the hot water heat exchanger. Controlling the amount of water flow is preferable in that the pressure of the refrigerant can be prevented from rising more than necessary, and the power consumption can be reduced.
[0012]
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.
[0013]
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.
[0014]
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 . Then, it is preferable at the point which can supply the remaining heat of an engine to a refrigerant | coolant via a warm water heat exchanger, and can also continue vehicle interior heating.
[0015]
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.
[0016]
What is necessary is just to connect the heater core which heats the air after passing a 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.
[0017]
It is preferable that the engine coolant flowing through the hot water heat exchanger and the refrigerant are in a counterflow.
[0018]
Note that CO ₂ can be used as the refrigerant.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to the accompanying drawings.
[0020]
FIG. 1 shows a vehicle air conditioner according to this embodiment. This vehicle air conditioner includes a blower (not shown), a vehicle interior heat exchanger 2, a mix damper (not shown), a heater core 3, and an auxiliary heater 4 in an air conditioning unit 1 at the front of the vehicle. Are sequentially arranged.
[0021]
The blower rotates by driving a blower motor (not shown), and guides the inside air or outside air selected by the inside / outside air switching damper (not shown) into the air conditioning unit 1.
[0022]
The vehicle interior heat exchanger 2 includes two heat exchange portions 5a and 5b divided in the upstream and downstream direction of the air flow in the air conditioning unit 1. An expansion valve 6 and an on-off valve 7 are connected in parallel between the downstream heat exchange unit 5a and the upstream heat exchange unit 5b. When the vehicle interior heat exchanger 2 is used for cooling as usual, if the opening / closing valve 7 is fully opened, the air passing through any of the upstream and downstream heat exchange portions 5a, 5b can be cooled. Further, when the vehicle interior heat exchanger 2 is used for heating, if the opening / closing valve 7 is fully opened, the air passing through any of the upstream and downstream heat exchange portions 5a and 5b can be heated. In this case, if the on-off valve 7 is fully closed, the air passing through the upstream heat exchange section 5b can be dehumidified and heated by the downstream heat exchange section 5a.
[0023]
The vehicle interior heat exchanger 2 is provided in the middle of a refrigeration cycle C that is switched by a four-way valve 8. In the refrigeration cycle C, by switching the four-way valve 8 in the direction indicated by the solid line in FIG. 1, the refrigerant discharged from the compressor 9 is converted into the vehicle exterior heat exchanger 10, the pressure control valve 11, the vehicle interior heat exchanger 2, And it returns to the compressor 9 via the accumulator 12 and circulates. Further, by switching the four-way valve 8 in the direction indicated by the dotted line in FIG. 1, the refrigerant discharged from the compressor 9 causes the vehicle interior heat exchanger 2, the pressure control valve 11, the vehicle exterior heat exchanger 10, and the accumulator. 12 to return to the compressor 9 for circulation. That is, the cooling or heating by the vehicle interior heat exchanger 2 is possible by switching the four-way valve 8. A first three-way valve 13 is provided between the pressure control valve 11 and the vehicle exterior heat exchanger 10, and the refrigerant can bypass the vehicle exterior heat exchanger 10 and flow to the accumulator 12 through the hot water heat exchanger 14. A bypass path B1 is connected. In addition, a second three-way valve 15 is provided between the four-way valve 8 and the vehicle interior heat exchanger 2, so that the refrigerant bypasses the vehicle interior heat exchanger 2 and can flow toward the hot water heat exchanger 14. Bypass path B2 is connected. Note that CO ₂ is used as the refrigerant.
[0024]
The power of the engine 16 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 2 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 2 absorbs heat from the inside air or outside air passing through the outside by the refrigerant flowing inside. The temperature sensor 17 detects the temperature of the refrigerant flowing out from the vehicle exterior heat exchanger 10, and the pressure sensor 18 detects the pressure of the refrigerant discharged from the compressor 9. The accumulator 12 is provided in order to return the refrigerant to the compressor 9 in a state where the refrigerant is surely vaporized.
[0025]
The heater core 3 is disposed in one flow path branched by a mix damper (not shown), 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 20 disposed in the front part of the vehicle by switching the third three-way valve 19 and is radiated by the heater core 3 in the middle of the circuit. Further, the warm water heat exchanger 14 is provided in the middle of the heating cycle H, and the fourth three-way valve 21 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 14, the refrigerant and the engine cooling water are configured to face each other, and the heat exchange performance is improved. In the middle of the heating cycle H, an electric pump 22 and a water temperature detection sensor 23 are provided. The electric pump 22 can be driven by power supplied from the battery when the engine 16 is stopped. The water temperature detection sensor 23 detects the temperature of engine cooling water. The detected temperature is used to determine whether to supply engine cooling water to the hot water heat exchanger 14 by switching the fourth three-way valve 21.
[0026]
The auxiliary heater 4 assists the heating of the heater core 3 with power supplied from the battery when the engine 16 is stopped.
[0027]
The opening degree of the pressure control valve 11 is controlled by the control device 24 based on the rotational speed of the blower motor and the compressor 9 and the rotational position of the inside / outside air switching damper. Based on various conditions inside and outside the vehicle obtained from the inside air sensor 25, outside air sensor 26, solar radiation sensor 27, etc., the control device 24 drives the rotational speed of the blower motor and the compressor 9, the opening degree of the mix damper, each three-way valve 13, The switching of 15, 19, 21 and the opening degree of the expansion valve 16 are controlled.
[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. In the case of cooling operation, the four-way valve 8, the first three-way valve 13, and the second three-way valve 15 are switched, and the refrigerant discharged from the compressor 9 is transferred to the vehicle interior heat exchanger 2, the pressure control valve 11, the vehicle exterior. The heat is returned to the compressor 9 through the heat exchanger 10 and the accumulator 12 and circulated. In the vehicle interior heat exchanger 2, the open / close valve 7 is fully opened, so that the air passing through the heat exchange portions 5a and 5b can be cooled and dehumidified.
[0029]
In the case of heating operation, first, various conditions inside and outside the vehicle such as the inside air temperature detected by the inside air sensor 25, the outside air temperature detected by the outside air sensor 26, the amount of solar radiation detected by the solar radiation sensor 27, and the set temperature in the vehicle are read. (Step S1), the driving speed of the compressor 9 and the opening degree of the mix damper are determined based on the vehicle interior and exterior conditions (Step S2).
[0030]
Here, the engine cooling water temperature _TE is read based on the detection signal from the water temperature detection sensor 23 (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 cooling water at that temperature is passed through the heater core 3, 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 3 performs normal heating only by the heater core 3. In the refrigeration cycle C, by switching the four-way valve 8, the refrigerant is passed from the compressor 9 via the vehicle exterior heat exchanger 10, the pressure control valve 11, the vehicle interior heat exchanger 2, the hot water heat exchanger 14, and the accumulator 12. It circulates in the cooling mode returning to the compressor 9 and cools and dehumidifies the air passing through the vehicle interior heat exchanger 2. 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 2 is lowered, the heating capacity of the heater core 3 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 third three-way valve 19 from being radiated by the radiator 20 (step S5). Further, since heating by the heater core 3 is insufficient, the four-way valve 8 is switched so that the refrigerant discharged from the compressor 9 flows directly into the vehicle interior heat exchanger 2 (step S6). At this time, in the vehicle interior heat exchanger 2, the open / close valve 7 is fully opened so that the air passing through both the heat exchange parts 5 a and 5 b can be heated. Further, the pressure P _V of the refrigerant to be detected to determine whether lower than the set pressure P _S by the pressure sensor 18 (step S7). The set pressure P _S, the refrigerant is allowed to flow into the vehicle-side heat exchanger 2 at this pressure below the dissipating the air passing through the air conditioning unit 1, too many ratio of the liquid phase, the vehicle exterior side heat exchanger A value that does not allow the vehicle interior heat exchanger 10 to sufficiently raise the temperature by using only the heat absorption by 10 is used.
[0033]
If the pressure P _V of the refrigerant detected by the pressure sensor 18 is the set pressure P _S above, switches the first three-way valve 13 to the heat radiation from the refrigerant in the interior side heat exchanger 23 to the air flowing through the air conditioning unit 11 (Step S8).
[0034]
On the other hand, it is determined that when the pressure P _V of the refrigerant detected by the pressure sensor 18 is less than the set pressure P _S, is a state that can not be fully exhibited the heating performance of the interior heat exchanger 2, the second The three-way valve 15 is switched to bypass not only the vehicle exterior heat exchanger 10 but also the vehicle interior heat exchanger 2 (step S9). As a result, heat can be absorbed by the hot water heat exchanger 14 without radiating heat from the refrigerant, so that the refrigerant can be brought to a high temperature / high pressure state at an early stage and heating required for the vehicle interior heat exchanger 2. Performance can be obtained in a short time.
[0035]
Thereafter, since the heat exchange efficiency of the vehicle interior heat exchanger 2 (between refrigerant and air) is known, the target air blowing temperature and the target air blowing amount 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 2 is determined based on the calculated target ventilation temperature and target ventilation volume, hot water heat exchange is performed so that this target condensation capacity can be obtained. The amount of engine cooling water that flows into the vessel 14 is adjusted by controlling the rotational speed of the electric pump 22 (step S11). Thereby, it is possible to cause the refrigerant to absorb heat from the engine coolant in the hot water heat exchanger 14 and appropriately perform heating in the vehicle interior heat exchanger 2 thereafter.
[0036]
In this way, since the refrigerant that has been brought into a high temperature / high pressure state by the compressor 9 can be caused to flow into the vehicle interior heat exchanger 23, the lack of heating capacity of the heater core 3 can be compensated by the vehicle interior heat exchanger 2. 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 by bypassing the vehicle interior heat exchanger 2, the auxiliary heating by the vehicle interior heat exchanger 2 can no longer be performed, so the auxiliary heater 4 is energized from the battery, and the heater core 3 is heated by the auxiliary heater 46. The lack of capability is compensated (step S12).
[0038]
Further, when dehumidification is performed when the temperature of the engine cooling water is not so high and the heating capacity of the heater core 3 is insufficient, the downstream heat exchange section 5a of the vehicle interior heat exchanger 2 and the upstream heat The on-off valve 7 connected to the exchange unit 5b is fully closed. As a result, the refrigerant flows into the downstream heat exchange section 5a, dissipates heat and liquefies, and then passes through the expansion valve 6 to be easily vaporized, and is vaporized when passing through the upstream heat exchange section 5b. Heat is absorbed from the air passing outside. That is, it is possible to perform dehumidification heating by heating in the downstream heat exchange section 5a while dehumidifying in the upstream heat exchange section 5b.
[0039]
As described above, according to the vehicle air conditioner according to the above-described embodiment, the vehicle interior heat exchanger 2 is used as auxiliary heating even if the temperature of the engine coolant is not sufficiently increased immediately after the engine 16 is started. Can be used. Moreover, not only the temperature of the refrigerant is raised by the hot water heat exchanger 14, but also the vehicle interior heat exchanger 2 is bypassed when the refrigerant is not sufficiently warmed. In addition, while the vehicle interior heat exchanger 2 cannot be used, the auxiliary heater 4 can be used.
[0040]
In the above embodiment, as the heating conditions for changing the switching direction of the first three-way valve 13, 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 14 or the outside air temperature may be used. In short, any parameter that can determine whether or not sufficient heating capacity can be obtained by the vehicle interior heat exchanger 2 can be used as the heating condition. The use of the outside air temperature for the heating condition is limited to the case where the outside air introduction mode is selected.
[0041]
In the above embodiment, the compressor 9 is driven based on the power of the engine 16, but it may be an electric type that can be driven by the power supplied from the battery. According to this, even when the engine 16 is stopped, the refrigerant is circulated and air conditioning by the vehicle interior heat exchanger 2 becomes possible.
[0042]
【The invention's effect】
As is apparent from the above description, according to the present invention, the four-way valve is switched, the channel switching means is switched to the bypass channel, and the engine cooling water is caused to flow through the hot water heat exchanger, whereby the vehicle interior heat exchange is performed. Since the heating by the heater is started, 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;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Air-conditioning unit 2 ... Car interior heat exchanger 3 ... Heater core 4 ... Auxiliary heater 5 ... Heat exchange part 6 ... Expansion valve 7 ... Open / close valve 8 ... Four-way valve 9 ... Compressor 10 ... Car exterior heat exchanger 11 ... Pressure control valve DESCRIPTION OF SYMBOLS 13 ... 1st 3 way valve 14 ... Hot water heat exchanger 15 ... 2nd 3 way valve 17 ... Temperature sensor 18 ... Pressure sensor 19 ... 3rd 3 way valve 21 ... 4th 3 way valve 22 ... Electric pump 23 ... Water temperature detection sensor 24 ... Control apparatus

Claims (9)

In a vehicle air conditioner comprising a compressor, a vehicle exterior heat exchanger, a pressure control valve, a vehicle interior heat exchanger, and an accumulator,
The vehicle interior heat exchanger is composed of a plurality of heat exchange parts by dividing the air flow in the air conditioning unit in the upstream and downstream direction, and an expansion valve is connected in the middle of the pipe connecting the heat exchange parts,
Cooling mode in which refrigerant discharged from the compressor circulates in the order of the vehicle exterior heat exchanger, pressure control valve, vehicle interior heat exchanger, and accumulator, or vehicle interior heat exchanger, pressure control valve, vehicle exterior heat exchange A four-way valve that switches the flow path to either one of the heating mode that circulates in the order of the condenser and the accumulator,
When the flow path is switched to the heating mode by the four-way valve, a bypass flow path in which the refrigerant bypasses the outside heat exchanger,
A hot water heat exchanger that is disposed in the middle of the bypass flow path and exchanges heat between the refrigerant and the engine coolant;
An auxiliary bypass passage through which the refrigerant from the compressor is guided to the hot water heat exchanger by bypassing the vehicle exterior heat exchanger and the vehicle interior heat exchanger;
In addition to the refrigeration cycle or the bypass channel, channel switching means for switching the channel to the auxiliary bypass channel;
When the four-way valve is switched and the refrigerant is circulated in the heating mode, the flow path switching means switches the flow path to the bypass flow path, and causes the engine cooling water to flow to the hot water heat exchanger. Control means for starting heating by the inner heat exchanger;
Provided,
The control means switches the flow path from the start of the heating operation by switching the four-way valve to drive the compressor until the heating condition that enables normal heating only by the vehicle interior heat exchanger is satisfied. A vehicle air conditioner characterized in that the channel is switched to an auxiliary bypass channel by means .   The control means determines a target condensing capacity by the in-vehicle heat exchanger based on a target air temperature and a target air amount calculated from a difference between the set temperature and the inside air temperature, and cools the engine in the hot water heat exchanger. The vehicle air conditioner according to claim 1, wherein the amount of water flow is controlled.   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 a compressor.   The heater core which heats the air after passing the vehicle interior heat exchanger is 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.   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

Images