JP2000016072A - Cooling and heating device for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dehumidifying heat pump type cooling and heating device for an automobile suitable for an electric automobile capable of dehumidifying heating by simplified system constitution requiring no cooling medium recovery line and reduced in the number of parts. SOLUTION: An electric compressor 7, a sub-condenser 4, a main condenser 5, a check valve 24, a liquid tank 9, a first expansion valve 10, and an evaporator 3 are connected by coolant piping in this order, an outlet of the sub- condenser 4 and an inlet of the liquid tank 9 are connected to each other by a bypass pipe 21, a solenoid valve 22 is provided on inlet side piping of the main condenser 5, and a second expansion valve 23 is provided on the bypass pipe 21. At the time of cooling operation, the solenoid valve 22 is opened, and in heating operation, the solenoid valve 22 is closed. Recovery of coolant is executed by a so-called hot gas bypass method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump system having a dehumidifying function for performing dehumidifying and heating in a vehicle compartment.
In particular, the present invention relates to an improvement of an air conditioner for a vehicle suitable for an electric vehicle.

[0002]

2. Description of the Related Art For example, an electric vehicle has an insufficient heating heat source as compared with a vehicle equipped with an engine that uses high-temperature engine cooling water, because a traveling drive source is an electric motor. For this reason, in a conventional electric vehicle cooling / heating apparatus, a heat pump type car capable of dehumidifying and heating is capable of performing a cycle operation using a refrigerant not only for cooling but also for heating, thereby heating the passenger compartment while preventing window fogging. An air conditioner (hereinafter, referred to as a "dehumidification heat pump system") has been developed (for example, see Japanese Patent Application Laid-Open No. 5-201243).

As shown in FIG. 3, for example, an air conditioner for an electric vehicle of this type includes a blower device 2 for introducing air into a duct 1, an evaporator 3, and a sub-unit on the indoor side which mainly functions during a heating operation, as shown in FIG. A condenser 4 is provided. Further, outside the duct 1, an outdoor main condenser 5 mainly functioning during cooling operation is provided.

The sub-condenser 4 and the main condenser 5 are switched between a heating operation and a cooling operation by a four-way valve 6 provided in the refrigeration cycle. In the heating operation, the refrigerant bypasses the main condenser 5. The refrigerant discharged from the electric compressor 7 flows through the four-way valve 6 → the bypass passage 8 → the sub condenser 4 → the liquid tank 9 → the expansion valve 10 → the evaporator 3 and returns to the compressor 7 (heating cycle). . In this circulation process, the gas refrigerant discharged from the compressor 7 and bypassing the main condenser 5 by the four-way valve 6 is condensed and liquefied by the sub condenser 4 and radiates heat, so that the air dehumidified (and cooled) by the evaporator 3 The vehicle is heated by the condenser 4 and the interior of the vehicle is dehumidified and heated.

A refrigerant recovery passage 11 is provided between the outlet side (one of the outlet ports) of the four-way valve 6 and the suction side of the compressor 7, and an electromagnetic valve 12 is provided in the refrigerant recovery passage 11. Installed. When the outside air temperature is low at the start of the heating operation, the four-way valve 6 allows the refrigerant recovery passage 11 to communicate with the main condenser 5.
By opening 2, the so-called stagnation refrigerant mainly staying in the main condenser 5 is returned to the compressor 7 to compensate for the shortage of the refrigerant in the heating cycle.

In FIG. 3, reference numerals 13, 14, and 15 denote check valves, 16 an air mix door, and 17 a condenser fan.

[0007]

However, in such a conventional dehumidifying heat pump system, although a sufficient dehumidifying and heating effect can be exhibited, since the configuration of the entire system including the refrigeration cycle is complicated, the following problems are involved. Can be a problem.

First, in the conventional configuration, the refrigerant tends to accumulate in the main condenser 5 and the like when the outside air temperature is low (the presence of the stagnant refrigerant). Therefore, in order to secure the amount of the refrigerant circulating in the cycle during the heating operation. As described above, it is necessary to provide a line (the four-way valve 6, the refrigerant recovery passage 11, the electromagnetic valve 12, and the like) for recovering the sleeping refrigerant and to control the line.

Secondly, in the conventional configuration, valves such as the four-way valve 6 and the check valves 13 to 15 are used to switch the flow of the refrigerant between the heating operation and the cooling operation or to recover the stagnant refrigerant. However, due to the addition of such valves, measures must be taken to ensure operational reliability, and further, there is a possibility that operating noise will be generated and costs and weight will increase.

The present invention has been made in view of the above-mentioned problems in the conventional dehumidifying heat pump system, and has a simplified system configuration in which a refrigerant recovery line is unnecessary and the number of parts is reduced, and the reliability is improved. It is an object of the present invention to provide a new heat pump type heating / cooling apparatus for a vehicle capable of dehumidifying and heating which can improve the cost and reduce the cost.

[0011]

The above object of the present invention is achieved by the following means.

(1) An automotive air conditioner according to the present invention is a heat pump type automotive air conditioner which dehumidifies and heats the interior of a vehicle by utilizing the heat of a refrigerant circulating while changing the state of a refrigeration cycle. The indoor condenser disposed in the vehicle interior, the outdoor condenser disposed outside the vehicle interior, the liquid tank, the first expansion valve, and the evaporator disposed in the vehicle interior are connected in this order by refrigerant piping, and the outlet of the indoor condenser is connected. And the inlet of the liquid tank are connected by a bypass pipe, an electromagnetic valve is provided on the inlet side pipe of the outdoor condenser, a second expansion valve is provided on the bypass pipe, and refrigerant flowing out of the indoor condenser is provided.
In the cooling operation, the electromagnetic valve is opened and guided to the outdoor condenser side, and in the heating operation, the electromagnetic valve is closed and guided to the bypass pipe side.

(2) The outlet pipe of the outdoor condenser is provided with a check valve which allows only the flow from the outdoor condenser to the liquid tank.

(3) The automotive air conditioner according to the present invention is a heat pump type automotive air conditioner that performs dehumidification and heating of the vehicle interior by utilizing the heat of the refrigerant circulating while changing the state in the refrigeration cycle. The indoor condenser disposed in the vehicle interior, the outdoor condenser disposed outside the vehicle interior, the liquid tank, the first expansion valve, and the evaporator disposed in the vehicle interior are connected in this order by refrigerant piping, and the outlet of the indoor condenser is connected. And an inlet of the first expansion valve are connected by a bypass pipe, an electromagnetic valve is provided in an inlet pipe of the outdoor condenser, a second expansion valve is provided in the bypass pipe, and refrigerant flowing out of the indoor condenser is cooled. During operation, the solenoid valve is opened and guided to the outdoor condenser side, and during heating operation, the solenoid valve is closed and guided to the bypass pipe side. It is characterized in.

(4) The outlet pipe of the liquid tank is provided with a check valve that allows only the flow from the outdoor condenser to the first expansion valve via the liquid tank and the first expansion valve.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a vehicle air conditioner according to an embodiment of the present invention, which is mounted on an electric vehicle. Note that, in the figure, members common to FIG. 3 are denoted by the same reference numerals.

This electric vehicle cooling and heating apparatus is a dehumidifying heat pump system for performing cooling and dehumidifying heating in a vehicle cabin by performing a cycle operation using a refrigerant for both cooling and heating. The conventional dehumidifying heat pump system shown in FIG. It is a new type of improved version.

The refrigeration cycle of this system includes an electric compressor 7 (hereinafter simply referred to as a “compressor”), a sub-condenser 4 as an indoor condenser disposed in the vehicle interior, a main condenser 5 as an outdoor condenser disposed outside the vehicle interior, The liquid tank 9, the first expansion valve 10, and the evaporator 3 arranged in the vehicle cabin are connected in this order by refrigerant piping, and the outlet of the sub-condenser 4 and the inlet of the liquid tank 9 are connected by a bypass pipe 21, It is configured such that a refrigerant is sealed therein. That is, unlike the conventional system shown in FIG.
The refrigerant discharged from the compressor 7 is immediately led to the sub-condenser 4 and passed therethrough.
Side or direct evaporator 3 side (that is, bypass pipe 2
(1 side). An electromagnetic valve 22 and a second expansion valve 23 are installed on both branch paths, respectively. Specifically, an electromagnetic valve 22 is provided on an inlet side pipe of the main condenser 5 and a bypass pipe 21 is provided.
Are provided with second expansion valves 23, respectively. Both the first expansion valve 10 and the second expansion valve 23 are normal temperature-operated expansion valves, and the valves operate by receiving feedback from a heat-sensitive cylinder provided at an outlet pipe of the evaporator 3 to adjust the refrigerant flow rate. It is supposed to.

Further, in order to completely prevent the refrigerant flowing through the bypass pipe 21 from flowing back toward the main condenser 5, it is preferable that the outlet pipe of the main condenser 5 be provided with:
A check valve 24 that allows only the flow from the main condenser 5 to the liquid tank 9 is provided.

Therefore, when comparing the new system with the conventional system, the conventional system requires one four-way valve, one solenoid valve, three check valves, and one expansion valve. In contrast, this system requires only one solenoid valve, one check valve, and two expansion valves.
Although the number of expansion valves is increased by one, an expensive four-way valve is not required, and two check valves can be reduced. As a result, the number of parts and the cost are reduced as a whole.

Further, in the present system, the stagnation refrigerant can be recovered by a method described later.
As shown in (1), the refrigerant recovery line (refrigerant recovery passage 11 and the like) in the conventional system is unnecessary, and the piping route is simplified and shortened as compared with the conventional system.

As described above, in the present system, in the configuration of the refrigeration cycle, the refrigerant recovery line is unnecessary and the number of parts is reduced, so that the system is greatly simplified as compared with the conventional system. .

The configuration of this system other than the refrigeration cycle is exactly the same as the conventional system shown in FIG.

That is, this electric vehicle air conditioner has an air conditioning unit which selectively takes in air inside and outside the vehicle (inside / outside air), air-conditions the air, and blows the air toward a predetermined place into the vehicle interior. The unit has a duct 1 for sending the taken air toward the passenger compartment. In the duct 1, an intake door (not shown) that selectively opens and closes an inside air intake and an outside air intake (both not shown) is selected from the upstream side in the air flow direction indicated by a white arrow, and the intake door is selected by the intake door. Blower device 2 that introduces inside and outside air into duct 1 and feeds it downstream
The evaporator 3 that evaporates the refrigerant to cool the air and the sub-condenser 4 that functions mainly during the heating operation to condense and liquefy the gas refrigerant and heat the air are arranged. An air mix door 16 for adjusting the ratio of air passing through the sub-condenser 4 and air bypassing the sub-condenser 4 is rotatably provided on the front surface of the sub-condenser 4. Are formed with various air outlets (not shown) (eg, vent air outlets, foot air outlets, differential air outlets, etc.) for blowing the temperature-controlled air toward a predetermined place in the vehicle compartment.

On the other hand, a condenser fan 17 for supplying air to the main condenser 5 is provided on the back of the main condenser 5 arranged outside the duct 1, that is, on the downstream side of the air flow. The main condenser 5 mainly functions during the cooling operation, and cools the gas refrigerant by heat exchange with air to condense and liquefy.

The liquid tank 9 and the expansion valves 10 and 2
The function of No. 3 is well known. That is, in the former, the gas refrigerant is separated and the liquid refrigerant is stored once, and only the liquid refrigerant is stored in the expansion valve 1.
It is sent to zero and usually has a function of separating air and removing moisture and foreign matter. In addition, the latter has a function of decompressing and expanding the liquid refrigerant into a low-temperature and low-pressure mist-like refrigerant that is easy to evaporate, and has a function of automatically adjusting the refrigerant flow rate by sensing the evaporator outlet temperature.

Next, the operation will be described.

In the present invention, switching between cooling and heating is performed using only one solenoid valve 22 without using a four-way valve. Specifically,
It is as follows.

During the cooling operation, the solenoid valve 22 is opened, and the refrigerant flowing out of the sub-condenser 4
Lead to the side. That is, the refrigerant discharged from the compressor 7 is sub-condenser 4 → solenoid valve 22 → main condenser 5 → check valve 24 → liquid tank 9 → first expansion valve 10
→ It flows to the evaporator 3 and returns to the compressor 7 (cooling cycle). At this time, the air mix door 16
Is set to, for example, the position B in FIG. 1 so that the air after passing through the evaporator 3 does not pass through the sub-condenser 4. Thus, the high-temperature and high-pressure gas refrigerant discharged from the compressor 7 enters the sub-condenser 4 once, but the passage of air, that is, the heat exchange with the air is prevented by the air mixing door 16, so that the sub-condenser 4 almost radiates heat. Instead, it flows directly into the main condenser 5 through the solenoid valve 22, where it is exchanged with outside air and condensed and liquefied. The medium-temperature high-pressure liquid refrigerant flowing out of the main condenser 5 is extracted in the liquid tank 9 and is adiabatically expanded by the first expansion valve 10 provided at the inlet of the evaporator 3 to be a low-temperature low-pressure mist refrigerant. Be guided.
The low-temperature and low-pressure mist refrigerant becomes a low-temperature and low-pressure gas refrigerant while cooling the intake air by heat exchange in the evaporator 3, and is returned to the compressor 7. In this way, cooling of the vehicle interior is performed.

During the cooling operation, a part of the refrigerant flowing out of the sub-condenser 4 can pass through the second expansion valve 23 and bypass the main condenser 5, but both of the main condenser 5 and the second expansion valve 23 can be bypassed. For example, when the maximum cooling is required, the refrigerant pressure loss of the former is about 1 kg / cm ² , whereas the refrigerant pressure loss of the latter is about 12 kg / cm ^2. Yes, bypass flow is small. Therefore, the cooling performance does not decrease due to such a bypass flow rate. Rather, since the small amount of the refrigerant, which has been reduced in pressure and reduced in temperature through the second expansion valve 23, merges with the liquid refrigerant discharged from the main condenser 5 and cools it, the cooling performance is improved. I do. Specifically, the coefficient of performance COP is improved by about 10%.

On the other hand, during the heating operation, the solenoid valve 22 is closed, and the refrigerant flowing out of the sub-condenser 4
It is led to one side, that is, directly to the evaporator 3 side. That is, the refrigerant discharged from the compressor 7 is
→ second expansion valve 23 → liquid tank 9 → first expansion valve 10
→ It flows to the evaporator 3 and returns to the compressor 7 (heating cycle). At this time, the air mix door 16
Is set, for example, at position A in FIG. 1 so that all the air after passing through the evaporator 3 passes through the sub-condenser 4. Thereby, the high-temperature and high-pressure gas refrigerant discharged from the compressor 7 enters the sub-condenser 4 and
Here, heat is released to the intake air to be condensed and liquefied, and becomes a medium-temperature, high-pressure liquid refrigerant. This liquid refrigerant is introduced into the bypass pipe 21, reaches the liquid tank 9 through the second expansion valve 23, further passes through the first expansion valve 10 (so-called two-stage expansion), and is adiabatically expanded in this process to be a low-temperature low-pressure mist. After it becomes a state refrigerant, the intake air is cooled by heat exchange in the evaporator 3.
It is dehumidified and returned to the compressor 7. In this way, the intake air cooled and dehumidified by the evaporator 3 is heated by the sub-condenser 4 and blown out into the vehicle interior, so that the vehicle interior is dehumidified and heated. As described above, both the first expansion valve 10 and the second expansion valve 23 are temperature-operated expansion valves and have a function of controlling the refrigerant flow rate by feeding back the outlet temperature (degree of superheat) of the evaporator 3. During this heating operation, the second expansion valve 23 located on the upstream side serves as a main throttle, and the first expansion valve 10 on the downstream side has a small throttle action because of a low inlet pressure, and is ancillary. In addition, a liquid tank 9 which is a container disposed outside the vehicle compartment
Can function also as an outdoor heat exchanger in which heat exchange (radiation) with outside air is performed when viewed as a heat pump system.

The temperature control is controlled by the air mix door 16.
Can be adjusted by adjusting the opening degree.

As described above, in the present system, the position of the sub-condenser 4 in the refrigeration cycle is changed as compared with the conventional system, and the sub-condenser 4 is moved to the position upstream of the main condenser 5 and before branching. Although it is provided in a form directly connected to the outlet, by providing the sub-condenser 4 at such a position, the compressor 7
The piping route between the outlet of the sub-condenser 4 and the inlet of the sub-condenser 4 is shortened, and the temperature of the gas refrigerant flowing through the sub-condenser 4 is reduced because the temperature of the gas refrigerant is reduced by the shortened piping route during the heating operation. As a result, the heating performance is improved.

Further, in the present invention, the refrigerant recovery line is not provided as described above. However, the shortage of the refrigerant during the heating operation is caused by increasing the capacity of the liquid tank 9 in advance in consideration of the stagnation of the refrigerant into the main condenser 5. By setting aside, it is possible to respond.

In the present system, the recovery of the refrigerant remaining in the main condenser 5 during the heating operation can be performed by appropriately controlling the opening and closing timing of the solenoid valve 22.

Specifically, for example, when the heating operation mode is selected manually or automatically, first, the solenoid valve 22 is opened as an initial state, the compressor 7 is started, and the refrigerant is caused to flow through the main condenser 5 for a predetermined time. (For example, about 30 seconds)
After the elapse, the solenoid valve 22 is closed (a so-called hot gas bypass method) to perform refrigerant recovery.

As described above, according to the present embodiment, an expensive four-way valve is not required, and two check valves can be reduced, so that operational reliability can be improved and valves and the like can be improved. The generation of operation noise is reduced, and the cost and weight are reduced by reducing the number of parts.

Further, since the bed refrigerant can be recovered by controlling the opening / closing timing of the solenoid valve 22, a dedicated refrigerant recovery line as in the prior art is not required, and the piping path is simplified and shortened accordingly. In this regard, the system can be simplified, reliability can be improved, and cost and weight can be reduced.

The sub capacitor 4 is connected to the compressor 7
, The piping path between the outlet of the compressor 7 and the inlet of the sub-condenser 4 is shorter than in the conventional system. Therefore, during the heating operation, the temperature of the gas refrigerant is prevented from dropping by the shortened length of the piping path, so that the temperature of the refrigerant flowing through the sub-condenser 4 becomes higher, and the heating performance is improved.

During the cooling operation, the bypass flow rate flowing through the second expansion valve 23 is small, and the refrigerant that has passed through the second expansion valve 23 and has been reduced in pressure and lowered in temperature is supplied to the main condenser 5.
This has the effect of cooling the liquid refrigerant that has flowed out, so that the cooling performance is improved and the coefficient of performance COP is improved.

During the heating operation, the liquid tank 9 is operated.
However, since it also functions as an outdoor heat exchanger for performing heat exchange with the outside air, the dehumidifying performance in the heating mode is improved.
That is, in the Mollier diagram, since the heat is further radiated in the liquid tank portion, the enthalpy at the evaporator inlet is reduced, and the refrigeration effect in the evaporator 3 is improved. Therefore, due to the improvement of the dehumidifying performance, window fogging is less likely to occur even if the ratio of inside air is increased, and heat loss can be reduced, resulting in fuel saving.

FIG. 2 is a schematic configuration diagram of a vehicle air conditioner according to another embodiment of the present invention, which is also mounted on an electric vehicle. In the figure, the same reference numerals are given to members common to FIGS. 2 and 3.

In the above-described embodiment shown in FIG. 1, the liquid tank 9 is provided on the downstream side of the bypass pipe 21, but in the embodiment shown in FIG. The liquid tank 9 is provided at an outlet side pipe of the main condenser 5, specifically, between the outlet of the main condenser 5 and the check valve 24. Thus, by providing the liquid tank 9 only in the cooling cycle,
Since the amount of refrigerant in the heating cycle is small in the first place,
Even when the refrigerant recovery amount is small at the time of refrigerant recovery, a heating cycle is established. Since the configuration, operation and effect other than this point are basically the same as those shown in FIG. 1, the description thereof is omitted.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the claims.

For example, in the above-described embodiment, ordinary temperature-operated expansion valves are used as the first and second expansion valves 10 and 23. However, considering the balance of the refrigeration cycle, both or one of them is used. It is also possible to use a fixed throttle (fixed expansion valve) such as an orifice.

In the above-described embodiment, the cooling / heating device for an electric vehicle has been described. However, the present invention is not limited to this, and is applicable to a cooling / heating device for a normal vehicle such as an engine-mounted vehicle. It goes without saying that you can do it.

[0048]

As described above, according to the present invention,
Since a dedicated refrigerant recovery line is not required and the number of valves can be reduced, the system can be simplified, the reliability in operation can be improved, and the cost and weight can be reduced.

Further, since the sub-condenser is directly connected to the outlet of the compressor, the temperature drop of the refrigerant discharged from the compressor and flowing into the sub-condenser is small, and the heating performance is improved.

Further, since the second expansion valve is provided in the bypass pipe, a small amount of refrigerant that has passed through the second expansion valve and has been reduced in pressure and cooled to cool the liquid refrigerant flowing out of the main condenser during the cooling operation. The cooling performance is improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a cooling and heating device for an electric vehicle according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an electric vehicle cooling / heating device according to another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing a conventional heat pump type air conditioner for an electric vehicle.

[Explanation of symbols]

 3 ... Evaporator, 4 ... Sub condenser, 5 ... Main condenser, 7 ... Electric compressor, 9 ... Liquid tank, 10 ... First expansion valve, 21 ... Bypass pipe, 22 ... Electromagnetic valve, 23 ... Second expansion valve, 24 ... Check valve.

Claims (4)

[Claims] 1. A heat pump type air conditioner for a vehicle that performs dehumidification and heating of a vehicle interior by using heat of a refrigerant circulating while changing a state in a refrigeration cycle. Capacitor
(4), an outdoor condenser (5), a liquid tank (9), a first expansion valve (10), and an evaporator (3) arranged inside the vehicle cabin arranged outside the vehicle cabin are connected in this order by refrigerant piping. An outlet of the indoor condenser (4) and an inlet of the liquid tank (9) are connected by a bypass pipe (21), and an electromagnetic valve (22) is provided on an inlet side pipe of the outdoor condenser (5), and the bypass is provided. A second expansion valve (23) is provided in the pipe (21), and the refrigerant flowing out of the indoor condenser (4) is guided to the outdoor condenser (5) by opening the solenoid valve (22) during cooling operation. During operation, the solenoid valve (22) is closed and the bypass pipe (21) is closed.
An automotive air conditioning system characterized by being guided to the side. 2. An outlet pipe of the outdoor condenser (5) is provided with the liquid tank (9) from the outdoor condenser (5).
The cooling and heating device for an automobile according to claim 1, further comprising a check valve (24) that allows only a flow toward the vehicle. 3. A heat pump type air conditioner for a vehicle that performs dehumidification and heating of a vehicle interior by using heat of a refrigerant circulating while changing a state in a refrigeration cycle, wherein a compressor (7) and a room arranged in the vehicle interior are provided. Capacitor
(4), an outdoor condenser (5), a liquid tank (9), a first expansion valve (10), and an evaporator (3) arranged inside the vehicle cabin arranged outside the vehicle cabin are connected in this order by refrigerant piping. , The outlet of the indoor condenser (4) and the first expansion valve (1).
0) is connected with a bypass pipe (21), an electromagnetic valve (22) is provided on the inlet side pipe of the outdoor condenser (5), and a second expansion valve (23) is provided on the bypass pipe (21). , The indoor condenser
The refrigerant flowing out of (4) is supplied to the solenoid valve (2
2) An air conditioner for automobiles, wherein 2) is opened and guided to the side of the outdoor condenser (5), and during heating operation, the solenoid valve (22) is closed and guided to the side of the bypass pipe (21). 4. An outlet pipe of the liquid tank (9) is provided with the liquid tank (9) from the outdoor condenser (5).
A check valve (24) is provided to allow only a flow toward the first expansion valve (10) via the first expansion valve (10).
4. The automotive cooling and heating device according to claim 1.