JP2003139431A - Vehicular air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To elevate a blowing temperature quickly even just after a heating operation start. SOLUTION: A four-way valve 5 is switched to circulate a refrigerant discharged from a compressor 6 through an indoor heat exchanger 2, a pressure control valve 8, an outdoor heat exchanger 7 and an accumulator 9 in this order. The passage is switched to a bypass passage B1 bypassing the outdoor heat exchanger 7 to develop heat exchange between the refrigerant and engine cooling water in a hot water heat exchanger 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner.

[0002]

2. Description of the Related Art Conventionally, as a vehicle air conditioner, an in-vehicle heat exchanger provided in the middle of a refrigeration cycle can be used not only for cooling the passing air but also for heating by reversing the circulation direction of the refrigerant. There is something I did. According to this, the air blown into the vehicle can be heated not only by the heater core through which the engine cooling water flows but also by the heat exchanger inside the vehicle.

[0003]

However, in the above-mentioned conventional vehicle air conditioner, when the outside air temperature is extremely low, etc., it is possible to perform heating by the heat exchanger inside the vehicle.
In-vehicle heating may not be started quickly.

Therefore, it is an object of the present invention to provide an air conditioning system for a vehicle, which can quickly raise the temperature of air blown immediately after the start of heating operation.

[0005]

As a means for solving the above problems, the present invention provides a vehicle air conditioner including a compressor, a heat exchanger outside the vehicle, a pressure control valve, a heat exchanger inside the vehicle, and an accumulator. In the cooling mode, the refrigerant discharged from the compressor is circulated in the order of an outer heat exchanger, a pressure control valve, an inner heat exchanger, and an accumulator, or an inner heat exchanger, a pressure control valve, an outer A heat exchanger, and a four-way valve that switches the flow path to either one of the heating modes that circulate in the order of the accumulator, and the refrigerant when the flow path is switched to the heating mode by the four-way valve,
A bypass flow path for bypassing the exterior heat exchanger, a hot water heat exchanger disposed in the middle of the bypass flow path for exchanging heat between the refrigerant and engine cooling water, and the four-way valve to switch the refrigerant. A control means for switching the flow path to the bypass flow path and flowing engine cooling water to the hot water heat exchanger when circulating in the heating mode to start heating by the in-vehicle heat exchanger; It is a thing.

With this structure, not only the four-way valve can be switched to perform heating by the heat exchanger inside the vehicle,
By switching to the bypass flow path, heat dissipation by the heat exchanger outside the vehicle can be prevented, and the coolant can be warmed by the engine cooling water. Therefore, even before the engine cooling water sufficiently rises, heating by the heat exchanger inside the vehicle can be started quickly and effectively, and the temperature of the air blown into the vehicle can be immediately increased. .

An auxiliary bypass flow passage having a pressure reducing valve for guiding the refrigerant from the compressor to the hot water heat exchanger by bypassing the heat exchanger outside the vehicle and the heat exchanger inside the vehicle is formed. The switching means is configured to be able to switch the flow path not only to the refrigeration cycle or the bypass flow path but also to the auxiliary bypass flow path, and the control means switches the four-way valve to drive the compressor to perform the heating operation. After starting, until the heating condition that enables desired heating by the in-vehicle heat exchanger is satisfied, the flow passage switching means switches the flow passage to the auxiliary bypass flow passage, thereby stabilizing the heating capacity. It is preferable in that the heating by the heat exchanger inside the vehicle can be started in this state.

The heating condition may be determined based on the elapsed time from the start of heating operation, the pressure of the refrigerant discharged from the compressor, the water temperature on the inlet side of the hot water heat exchanger, or the outside air temperature.

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, It is preferable in that the pressure of the refrigerant can be prevented from rising more than necessary and the power consumption can be reduced.

The target heating capacity may be changed based on the pressure of the refrigerant discharged from the compressor or the temperature of air blown into the vehicle. Based on the refrigerant pressure, the responsiveness can be improved, and based on the blowing temperature, the desired blowing temperature can be reliably obtained.

It is preferable to increase the driving speed of the compressor at the beginning of the heating operation, because the temperature of the air blown into the vehicle can be further increased.

It is preferable that the compressor is electrically driven so that the compressor can be driven even when the engine is stopped, because the interior heating can be continued.

An electric pump for circulating engine cooling water is provided between the engine and the hot water heat exchanger, and the electric pump is driven even when the engine is stopped, so that the engine cooling water is circulated. If possible,
It is preferable in that the residual heat of the engine can be supplied to the refrigerant through the hot water heat exchanger, and furthermore, the vehicle interior heating can be continued.

When the control means drives and controls the electric pump based on the pressure of the refrigerant discharged from the compressor, the control means can drive the electric pump only when necessary, which is preferable in that the power consumption can be suppressed.

A heater core for heating the air after passing through the in-vehicle heat exchanger may be connected in the middle of the hot water flow path connecting the engine and the hot water heat exchanger.

It is preferable that the engine cooling water flowing through the hot water heat exchanger and the refrigerant are in counterflow.

CO ₂ can be used as the refrigerant.

[0018]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a vehicle air conditioner according to this embodiment. This vehicle air conditioner includes a blower (not shown), a heat exchanger 2 inside the vehicle, a mix damper (not shown), a heater core 3, and an auxiliary heater 4 in the air conditioning unit 1 at the front of the vehicle from the upstream side. Are sequentially arranged.

The blower is rotated by driving a blower motor (not shown), and guides the inside air or the outside air selected by an inside / outside air switching damper (not shown) into the air conditioning unit 1.

The in-vehicle heat exchanger 2 is provided in the middle of the refrigeration cycle C which is switched by the four-way valve 5.
In the refrigeration cycle C, by switching the four-way valve 5 in the direction shown by the solid line in FIG. 1, the refrigerant discharged from the compressor 6 causes the heat exchanger 7 outside the vehicle, the pressure control valve 8, the heat exchanger 2 inside the vehicle, And, it returns to the compressor 6 through the accumulator 9 and circulates. Further, by switching the four-way valve 5 in the direction shown by the dotted line in FIG.
The refrigerant discharged from the inside of the vehicle is returned to the compressor 6 via the inside heat exchanger 2, the pressure control valve 8, the outside heat exchanger 7, and the accumulator 9 and circulates. That is, by switching the four-way valve 5, cooling or heating by the vehicle interior heat exchanger 2 is possible. A first three-way valve 10 is provided between the pressure control valve 8 and the vehicle exterior heat exchanger 7 so that the refrigerant bypasses the vehicle exterior heat exchanger 7 and can flow to the accumulator 9 via the hot water heat exchanger 11. Bypass path B1 is connected. Further, a second three-way valve 12 is provided between the four-way valve 5 and the heat exchanger 2 on the inside of the vehicle, so that the refrigerant is used as the heat exchanger 2
An auxiliary bypass passage B2 is connected which allows the fluid to flow around to the hot water heat exchanger 11 side. CO ₂ is used as the refrigerant.

The power of the engine 13 is transmitted to the compressor 6 via a clutch (not shown). The driving rotation speed of the compressor 6 can be switched in a plurality of stages (which may be infinite) by switching the clutch. The drive rotation speed of the compressor 6 is usually set to a value at which the refrigerant can flow through the vehicle exterior heat exchanger 7 at supercritical pressure. The exterior heat exchanger 7 is disposed in the front portion of the vehicle and radiates the refrigerant to the outside air. The pressure control valve 8 reduces the pressure of the refrigerant and supplies it to the vehicle interior heat exchanger 2 in a state where it is easily vaporized, and also serves to adjust the pressure thereof, as described later. The vehicle interior heat exchanger 2 absorbs heat from the inside air or the outside air passing through the outside by the refrigerant flowing inside. The temperature of the refrigerant flowing out of the vehicle interior heat exchanger 2 is detected by the temperature sensor 14, and the pressure of the refrigerant discharged from the compressor 6 is detected by the pressure sensor 15. Accumulator 9
Is provided to return the refrigerant to the compressor 6 in a state where the refrigerant is surely vaporized.

The heater core 3 is arranged in one of the flow paths divided by the mix damper, and constitutes one device of the heating cycle H. In heating cycle H,
By switching the third three-way valve 16 for engine cooling water,
It is circulated in a circuit separate from the radiator 17 arranged in the front part of the vehicle, and is radiated by the heater core 3 in the circuit.
In the middle of the heating cycle H, the hot water heat exchanger 11
Is provided, and by switching the fourth three-way valve 18, it is possible to perform heat exchange between the refrigerant flowing in the refrigeration cycle C and the engine cooling water flowing in the heating cycle H. In the hot water heat exchanger 11, the refrigerant and the engine cooling water are configured to flow in opposite directions, and the heat exchange performance is improved. An electric pump 19 and a water temperature detection sensor 20 are provided in the middle of the heating cycle H. The electric pump 19 can be driven by the electric power supplied from the battery when the engine 13 is stopped. The water temperature detection sensor 20 detects the temperature of the engine cooling water. The detected temperature is used to determine whether to switch the fourth three-way valve 18 to supply engine cooling water to the hot water heat exchanger 11.

The auxiliary heater 4 assists the heating of the heater core 3 by the electric power supplied from a battery (not shown) when the engine 13 is stopped.

The opening degree of the pressure control valve 8 is controlled by the control device 21 based on the driving rotational speed of the blower motor and the compressor 6, the rotational position of the inside / outside air switching damper, and the like. The control device 21 includes an inside air sensor 22,
Based on various conditions inside and outside the vehicle obtained from the outside air sensor 23, the solar radiation sensor 24, etc., the drive speeds of the blower motor and the compressor 6, the opening of the mix damper, the switching of each three-way valve, the opening of the pressure reducing valve, etc. are controlled. To do.

Next, the operation of the vehicle air conditioner having the above-mentioned structure 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.

First, various conditions inside and outside the vehicle such as the inside air temperature detected by the inside air sensor 22, the outside air temperature detected by the outside air sensor 23, the amount of solar radiation detected by the solar radiation sensor 24, and the set temperature in the vehicle are read (step S1), the drive speed of the compressor 6 and the opening degree of the mix damper are determined based on the vehicle interior and exterior conditions (step S2).

Here, the detection signal from the water temperature detection sensor 20
Based on the temperature T of the engine cooling water _ERead (step
Up S3). And the temperature of the engine cooling water read
T_EIs the set temperature T_SIs lower than
S4). Set temperature T_SThe temperature of the engine is cold
Even if waste water is passed through the heater core 3, the desired heating capacity
Use a value that does not give you strength.

The temperature T _E of the engine cooling water is set to the set temperature T _S.
In the above case, since sufficient heating capacity can be exhibited by heating the heater core 3, normal heating is performed only by the heater core 3. In refrigeration cycle C, four-way valve 5
By switching the refrigerant from the compressor 6 to the exterior heat exchanger 7, the pressure control valve 8, the interior heat exchanger 2,
It circulates in a cooling mode in which it returns to the compressor 6 via the hot water heat exchanger 11 and the accumulator 9 to cool and dehumidify the air passing through the in-vehicle heat exchanger 2. However, if the temperature T _E of the engine cooling water has not risen so much from the set temperature T _S , the temperature of the air passing through the dehumidifying operation by the in-vehicle heat exchanger 2 is lowered, so that the heating capacity of the heater core 3 is reduced. In such a case, the driving of the compressor 6 is stopped because there is a risk of shortage.

On the other hand, when the temperature T _E of the engine cooling water is lower than the set temperature T _S , the third three-way valve 16 is switched to prevent the engine cooling water from being dissipated by the radiator 17 (step S5). Further, since the heating by the heater core 3 is not sufficient, the four-way valve 5 is arranged so that the refrigerant discharged from the compressor 6 directly flows into the vehicle interior heat exchanger 2.
Is switched (step S6). At this time, it is determined whether or not the refrigerant pressure P _V detected by the pressure sensor 15 is lower than the set pressure P _S (step S7). When the refrigerant flows into the heat exchanger 2 on the inside of the vehicle at a pressure equal to or lower than the set pressure P _S to radiate heat to the air passing through the air conditioning unit 1, the proportion of the liquid phase becomes too large, and the heat exchanger on the outside of the vehicle A value is used so that the inside heat exchanger 2 cannot sufficiently raise the temperature only by the heat absorption by 7.

When the refrigerant pressure P _V detected by the pressure sensor 15 is equal to or higher than the set pressure P _S , the first three-way valve 10
And heat is radiated from the refrigerant to the air flowing in the air conditioning unit 11 by the heat exchanger 23 inside the vehicle (step S
8).

On the other hand, when the refrigerant pressure P _V detected by the pressure sensor 15 is less than the set pressure P _S, it is determined that the heating performance of the interior heat exchanger 2 cannot be sufficiently exerted. , The second three-way valve 12 is switched to bypass not only the exterior heat exchanger 7 but also the interior heat exchanger 2 (step S9). This allows the hot water heat exchanger 11 to absorb heat without radiating heat from the refrigerant, so that the refrigerant can be brought into a high temperature / high pressure state at an early stage, and the heating required for the vehicle interior heat exchanger 2 is achieved. Performance can be obtained in a short time.

After that, since the heat exchange efficiency of the heat exchanger 2 inside the vehicle (between the refrigerant and the air) is known, the above step S
The target air blowing temperature and the target air blowing amount are calculated based on the temperature difference between the set temperature and the inside air temperature read in step 1 (step S1).
0). Then, the target condensation capacity (target condensation pressure or target condensation temperature) of the vehicle interior heat exchanger 2 is determined on the basis of the calculated target air temperature and target air volume, so that the hot water heat exchange is performed so as to obtain this target air capacity. The amount of engine cooling water that flows into the container 11 is adjusted by controlling the drive rotation speed of the electric pump 19 (step S11). As a result, the hot water heat exchanger 11 can cause the refrigerant to absorb heat from the engine cooling water, and the subsequent heat in the vehicle interior heat exchanger 2 can be appropriately performed.

In this way, the refrigerant that has become high temperature and high pressure in the compressor 6 can be made to flow into the heat exchanger 23 inside the vehicle, so that the heating capacity of the heater core 3 is insufficient.
It can be supplemented by the heat exchanger 2 inside the vehicle. Therefore, even before the temperature of the engine cooling water rises, the interior heating of the vehicle at the desired blowing temperature is realized at an early stage.

When the refrigerant is allowed to flow by bypassing the heat exchanger 2 inside the vehicle, auxiliary heating by the heat exchanger 2 inside the vehicle cannot be performed. Therefore, the battery is energized to the auxiliary heater 4, and the auxiliary heater 46 causes a heater core. The heating capacity shortage of 3 is compensated (step S12).

As described above, according to the vehicle air conditioner according to the above-described embodiment, even if the temperature of the engine cooling water is not sufficiently increased immediately after the engine 13 is started, the inside heat exchanger 2 can be installed. Can be used as auxiliary heating. Moreover, not only is the temperature of the refrigerant raised by the hot water heat exchanger 11, but also the interior heat exchanger 2 is bypassed when the refrigerant is not sufficiently warm. Moreover,
The auxiliary heater 4 can be used while the vehicle interior heat exchanger 2 cannot be used.

In the above embodiment, the first three-way valve 10
Although the pressure P _V of the refrigerant discharged from the compressor 6 was used as the heating condition for changing the switching direction of the, the temperature of the refrigerant discharged from the compressor 6 and the engine at the inlet side of the hot water heat exchanger 11 The temperature of the cooling water or the outside temperature may be used. in short,
Any parameter can be used as the heating condition as long as it can determine whether or not sufficient heating capacity can be obtained by the vehicle interior heat exchanger 2. The outside air temperature is used as the heating condition only when the outside air introduction mode is selected.

Further, in the above embodiment, all the refrigerants bypass the in-vehicle heat exchanger 2 when the refrigerant is not sufficiently warmed, but only some of the refrigerants pass through the in-vehicle heat exchanger 2. It may be configured to bypass.

In the above embodiment, the compressor 6
Although it is driven based on the power of the engine 13, it may be an electric type that can be driven by the power supplied from the battery. According to this, even when the engine 13 is stopped, the refrigerant is circulated to allow cooling and heating by the vehicle interior heat exchanger 2.

[0040]

As is apparent from the above description, according to the present invention, by switching the four-way valve, switching to the bypass flow path by the flow path switching means, and flowing the engine cooling water to the hot water heat exchanger. Since the heating by the heat exchanger inside the vehicle is started, it is possible to immediately raise the temperature of the air blown into the vehicle and immediately heat the vehicle even immediately after the heating operation is started.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a vehicle air conditioner according to an embodiment.

FIG. 2 is a flow chart showing the contents of air conditioning control by the control device of FIG.

[Explanation of symbols]

1 Air conditioning unit 2 Inside heat exchanger 3 heater core 4 auxiliary heater 5 four-way valve 6 compressor 7 Outside heat exchanger 8 Pressure control valve 10 First three-way valve 11 Hot water heat exchanger 12 Second three-way valve 16 third three-way valve 18 4th three-way valve 19 Electric pump 20 Water temperature detection sensor 21 Control device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoichi Miyazaki             3-11 Yoshikawa Industrial Park, Higashihiroshima City, Hiroshima Prefecture             In ceremony company Japan Climate Systems F term (reference) 3L092 FA34 MA04 NA03 NA13 PA01                       PA13 PA15

Claims (12)

[Claims] 1. A vehicle air conditioner comprising a compressor, a heat exchanger outside the vehicle, a pressure control valve, a heat exchanger inside the vehicle, and an accumulator, wherein the refrigerant discharged from the compressor is a heat exchanger outside the vehicle A cooling mode in which the control valve, the heat exchanger inside the vehicle, and the accumulator are circulated in this order, or the heat exchanger inside the vehicle,
A four-way valve that switches the flow path to one of a heating mode in which the pressure control valve, the heat exchanger outside the vehicle, and the accumulator are circulated in this order, and a refrigerant when the flow path is switched to the heating mode by the four-way valve A bypass flow path for bypassing the outer heat exchanger, a hot water heat exchanger arranged in the middle of the bypass flow path for exchanging heat between the refrigerant and engine cooling water, and the four-way valve is switched to heat the refrigerant. And a control means for switching the flow path to the bypass flow path and flowing engine cooling water to the hot water heat exchanger to start heating by the in-vehicle heat exchanger when circulating in the mode. A vehicle air conditioner characterized by: 2. An auxiliary bypass flow path having a pressure reducing valve, which guides the refrigerant from the compressor 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 flow path, the flow path switching means is configured to be able to switch the flow path to the auxiliary bypass flow path, and the control means switches the four-way valve to drive the compressor. It is characterized in that the flow passage switching means switches the flow passage to the auxiliary bypass flow passage from the start of the heating operation to the satisfaction of the heating condition that enables desired heating by the heat exchanger inside the vehicle. The vehicle air conditioner according to claim 1. 3. The heating condition is determined based on any one of the elapsed time from the start of heating operation, the refrigerant pressure discharged from the compressor, the inlet side water temperature of the hot water heat exchanger, or the outside air temperature. The vehicle air conditioner according to claim 2, which is characterized in that. 4. 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 vehicle air conditioner according to any one of claims 1 to 3, wherein: 5. The vehicle air conditioner according to claim 4, wherein the target heating capacity is changed based on the pressure of the refrigerant discharged from the compressor or the temperature of the air blown into the vehicle. 6. The vehicle air conditioner according to any one of claims 1 to 5, wherein the drive speed of the compressor is increased at the beginning of the heating operation. 7. The vehicle air conditioner according to claim 1, wherein the compressor is electrically driven so that it can be driven even when the engine is stopped. . 8. An engine cooling water is provided between the engine and the hot water heat exchanger by providing an electric pump for circulating engine cooling water, and by driving the electric pump even when the engine is stopped. The vehicle air conditioner according to claim 6 or 7, which is capable of circulation. 9. The vehicle air conditioner according to claim 8, wherein the control means drives and controls the electric pump based on the pressure of the refrigerant discharged from the compressor. 10. A heater core for heating the air after passing through the heat exchanger inside the vehicle is connected in the middle of the hot water flow path connecting the engine and the hot water heat exchanger. 9. The vehicle air conditioner according to any one of 9 above. 11. The vehicle air conditioner according to claim 1, wherein the engine cooling water flowing through the hot water heat exchanger and the refrigerant are in counterflow. 12. The vehicle air conditioner according to any one of claims 1 to 11, wherein the refrigerant is CO ₂ .