JPH05272817A - Air conditioner - Google Patents

Abstract

PURPOSE:To perform a proper control over an enclosing amount of gaseous refrigerant (hot gas) of high temperature and high pressure within an auxiliary heating device, improve the heating capability and improve the durability thereof. CONSTITUTION:During an operation of an auxiliary heating device, refrigerant from a compressor 10 bypasses a condensor 11, flows at a bypassing pipe 20, passes through the second pressure reducing valve 22 and an evaporator 14, returns again to the compressor 10 and repeats this cycle. In this case, the pressure at high pressure of the refrigerant is detected by a pressure sensor 27 and an excessive state or lacked state of an amount of refrigerant is judged by an ECU 32. In the case that the amount of refrigerant is lack, the second solenoid valve 24 is closed, the first solenoid valve 23 and the third solenoid valve 25 are opened and then the refrigerant stored in the condensor 11 is supplemented to the hot gas refrigerant circuit. In the case that an excessive amount of refrigerant is found, the first solenoid valve 23 and the second solenoid valve 24 are opened, the third solenoid valve 25 is closed and the refrigerant within the hot gas refrigerant circuit is reduced. In addition, there may be provided a super heat sensing sensor for use in detecting an abnormal high pressure of the refrigerant and the like in a pipe 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to an air conditioner mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Publication No. 57-47829, there is known a device for defrosting an evaporator using a high-temperature and high-pressure gas refrigerant (hot gas) in a refrigerant circuit in a refrigeration cycle. ing. This device forms a cycle of switching to the defrosting operation when the evaporator is blocked by frost during the cooling operation, melting the frost of the evaporator, and returning the refrigerant in the gas state to the compressor via the accumulator.

As a conventional air conditioner mounted on a vehicle, a hot water heater using hot water for cooling an internal combustion engine mounted on the vehicle is generally used. This hot water heater is used as a main heating device, and a main heating device is used. The supplementary auxiliary heating system includes
Electric heaters, combustion heaters, heat pumps, etc. are used.

[0004]

However, according to such a conventional air conditioner, the above Japanese Patent Publication No. 57-478.
The device disclosed in Japanese Patent No. 29 is a device that defrosts frost formed during a cooling operation with high-temperature gas, and does not increase the heating capacity during heating. In addition, in the heating device that uses the electric heater, the combustion heater, and the heat pump as the auxiliary heating device in addition to the hot water heater of the main heating device, the hot water heater does not rise well when the internal combustion engine is started, and the electric heater is also used in combination. There is a problem that electric power shortage is likely to occur, there is a problem that the one that uses a combustion heater together tends to deteriorate safety, and one that also uses a heat pump has a problem such that it cannot be used in cold regions.

Therefore, in order to solve such a problem, in addition to a main heating device such as a hot water heater, a vehicle auxiliary for improving the heating capacity by utilizing a high-temperature high-pressure gas refrigerant (hot gas) in the refrigeration cycle. A heating system is possible. However, in the above-described vehicle auxiliary heating device that uses the high-temperature and high-pressure gas refrigerant in the refrigeration cycle, the excess or deficiency of the refrigerant charge amount greatly affects the heating capacity. For example, if the amount of the filled refrigerant is insufficient, the heating capacity is reduced, and if the amount of the filled refrigerant is excessive, the ON / OFF switching operation of the compressor is frequently performed, so that the durability of the magnet switch of the compressor is deteriorated.

The problem to be solved by the present invention is to provide an air conditioner capable of appropriately controlling the amount of high-temperature high-pressure gas refrigerant enclosed in the auxiliary heating device to improve the heating capacity and the durability. To do.

[0007]

An air conditioner according to the present invention for achieving the above object is an air conditioner having a main heating device, and is connected to a refrigerant compressor and a discharge side of the refrigerant compressor. A condenser, and a heat exchanger connected to the suction side of the refrigerant compressor, wherein an air flow path flowing through the heat exchanger and an air flow path heated by the main heating device at least partially coincide with each other. As described above, a heat exchanger provided in series with the main heating device, a first control valve provided in a path connecting the refrigerant compressor and the condenser, and the first control bypassing the condenser. A bypass pipe connected to a path connecting the condenser and the heat exchanger from the inlet side of the valve; a pressure reducing device provided in the middle of the bypass pipe; and a second control valve provided in the middle of the bypass pipe. , The capacitor A third control valve provided between the connecting portion of the outlet side of the bypass pipe, the refrigerant compressor,
It is characterized by further comprising: control means for releasing the refrigerant circulating through the bypass pipe, the pressure reducing device, and the heat exchanger to the condenser side, and control means for recovering the refrigerant from the condenser side.

[0008]

During heating, for example, as shown in FIG. 2, the compression work performed by the compressor of the air conditioner becomes heat work and is radiated by the evaporator through the pressure reducing device. Since the exhaust heat of the internal combustion engine that provides this compression work is transferred to the cooling hot water of the internal combustion engine, the amount of heat radiation from the heater core through which the cooling hot water flows increases. Because it is added to the heat radiation amount of
The heating capacity is improved.

When the amount of the charged refrigerant is insufficient, the second control valve is closed and the first control valve and the third control valve are opened,
In the hot gas refrigerant circuit, the hot gas refrigerant circuit is replenished with the refrigerant sunk in the condenser 11, and when the refrigerant is excessive, the first control valve and the second control valve are opened and the third control valve is closed. Reduce the refrigerant. As a result, the amount of refrigerant in the hot gas refrigerant circuit is maintained at an appropriate amount.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows a refrigerant circuit of a first embodiment in which the present invention is applied to a vehicle air conditioner. A cooling water pipe 2 communicating with a water jacket of an internal combustion engine 1 mounted on a vehicle communicates with a tube of a heater core 3a of a hot water heater 3, and the tube of the heater core 3a is connected to a water jacket of the internal combustion engine 1 by a cooling water return pipe 4. Communicate with the jacket. An on-off valve 5 is provided in the cooling water return pipe 4.

On the other hand, in the refrigerant circuit of the air conditioner 6, a compressor 10 driven by the internal combustion engine 1, a condenser 11, a receiver 12, a first pressure reducing device 29, and an evaporator 14 are sequentially connected by a pipe 16. One end 20a of the bypass pipe 20 that bypasses the condenser 11 is connected to the upstream side of the condenser 11 and the other end 20a of the bypass pipe 20 is connected.
b is connected to the pipe 16 between the first pressure reducing device 29 and the evaporator 14. The bypass pipe 20 is provided with a second pressure reducing device 22.

The proper pressure of the gas refrigerant controlled by the second pressure reducing device 22 is, for example, 15 to 20 kg / cm ² on the high pressure side of the second pressure reducing device 22, and ^{2 to 2 on} the low pressure side.
It is 4 kg / cm ² . This is because when the outside air temperature is low, the temperature on the low pressure side is also low, so the pressure on the high pressure side is kept high in order to obtain sufficient heating capacity, and as shown in FIG.
This is because it is necessary to increase the compression work due to the increase in the load. Therefore, the pressure on the high pressure side of the second pressure reducing device 22 is preferably in the range of 15 to 20 kg / cm ² .

A first solenoid valve 23 is provided between the one end 20a of the bypass pipe 20 and the condenser 11, and a second solenoid valve 24 is provided between the one end 20a of the bypass pipe 20 and the second pressure reducing device 22. Further, a third solenoid valve 25 is provided between the first pressure reducing device 29 and the other end 20b of the bypass pipe 20. The pressure sensor 27 is provided between the compressor 10 of the pipe 16 and the one end 20a of the bypass pipe 20.
Is input to the ECU 32 as an electronic control device.

The ECU 32 performs arithmetic processing based on the output signal of the pressure sensor 27, and as a result controls the open / closed states of the first solenoid valve 23, the second solenoid valve 24 and the third solenoid valve 25. Then, the ECU 32 appropriately outputs a drive signal for opening and closing the valve based on the control processing result to the first electromagnetic valve 23,
Input to the second solenoid valve 24 and the third solenoid valve 25.

The heater core 3a, which constitutes the main heating device, and the evaporator 14, which functions as an auxiliary heating device during heating, are arranged in series in a ventilation duct 26, and a blower fan 28 is provided.
Thus, the air taken into the ventilation duct 26 is blown into the vehicle compartment from an outlet (not shown) via the evaporator 14 and the heater core 3a. During cooling, the second solenoid valve 24 is closed, the first solenoid valve 23 and the third solenoid valve 25 are opened, and the refrigerant from the compressor 10 is caused to flow only to the condenser 11 side so that the refrigerant from the compressor 10 is discharged. , Capacitor 11, receiver 1
2, first decompression device 29, evaporator 14, compressor 1
It circulates in the order of 0. In the evaporator 14, the air sent from the blower fan 28 into the evaporator 14 is deprived of heat by the refrigerant to become cold air, which flows from the ventilation duct 26 in the direction of the arrow in the drawing, passes through the heater core 3a, and is blown out into the vehicle interior. At this time, the on-off valve 5 is closed and hot water does not flow to the heater core 3a.

During heating, the first solenoid valve 23 and the third solenoid valve 25 are closed, the second solenoid valve 24 is opened, and only the refrigerant bypass pipe 20 from the compressor 10 side is made to flow. The refrigerant is circulated through the second electromagnetic valve 24, the second pressure reducing device 22, the evaporator 14, and the compressor 10 in this order. The high-temperature and high-pressure refrigerant gas blown out by the compressor 10 is decompressed by the second decompression device 22 and changes into a high-temperature and low-pressure gas refrigerant. At this time, the on-off valve 5 is open and the heater core 3a
Warm water flows.

When the high-temperature low-pressure hot gas refrigerant passing through the second pressure reducing device 22 is introduced into the evaporator 14, the air that has taken heat from the high temperature gas is heated, and the hot water heater 3 on the downstream side in the direction of the arrow in the drawing is further heated. The heat is taken from the warm water in the heater core 3a to further heat the air, and the heated warm air is blown into the vehicle compartment from a blowout port (not shown). The change of the refrigerant is shown on the Mollier diagram, for example, as shown in FIG. That is, the first solenoid valve 23 and the third solenoid valve 25
Is closed and the second solenoid valve 24 is opened, the high-temperature high-pressure gas refrigerant compressed by the compressor 10 changes from low pressure P _L to high pressure P _H , and when it passes through the second pressure reducing device 22, the gas Pressure is high pressure P
It falls from _H to a low pressure P _L , enters the evaporator 14, and is then introduced to the inlet side of the compressor 10.

The compression work by the compressor 10 is shown in FIG.
As shown in, the pressure on the outlet side of the compressor 10 becomes high pressure P _H , and this high pressure P _H is preferably in the range of 15 to 20 kg / cm ² . The suction pressure of the compressor 10 is 1 to 5 kg
Blow pressure (high pressure P _H ) on the compressor outlet side in the range of / cm ²
Is more than 15 kg / cm ² , the compression power becomes larger.

According to the first embodiment, since the compressor 10 is driven by the internal combustion engine 1, the load of the internal combustion engine 1 increases, and the heat generated in the internal combustion engine is transferred to the cooling hot water, and the cooling hot water has this. The heat raises the temperature of the air blown by the heater core 3a, and the heating capacity of the heater core 3a also increases. Therefore, the high temperature and low pressure hot gas refrigerant in the evaporator 14 heats the air, and the heated air is further heated by the heater core 3a.
Thus, heat is taken from the hot water for cooling the internal combustion engine to be heated to a higher temperature. Therefore, the heating capacity of the air conditioner 6 is considerably increased. This enables rapid heating.

Next, valve control of the hot gas cycle, which is a characteristic part of the present invention, will be described based on the control flow shown in FIG. First, at step 40, the sensor signal of the pressure sensor 27 is taken into the ECU 32. Then step 41
Then, it is determined whether or not the rate of change ΔP _H / Δt of the high-pressure side pressure P _H in the pipe 16 per unit time is ΔP _H / Δt <K ₁ (where K ₁ : a constant). ΔP _H / Δt ≧
If it is determined that K _1, it is considered that the hot gas cycle is in a transient state, and the first to third solenoid valves 23, 24,
25 is not switched. If it is determined that ΔP _H / Δt <K ₁ , the hot gas cycle is considered to be in a steady state.

In the steady state, step 41 to step 4
2, the pressure P _H detected by the pressure sensor 27 is a constant K.
₂ (however, K ₂ > K ₁ ) is judged, and P _H ≦ K ₂
If it is determined that the amount of refrigerant is insufficient, the process proceeds to step 43, and the first solenoid valve 23 and the third solenoid valve 2 are determined.
5 is opened and the second solenoid valve 24 is closed. As a result, the refrigerant accumulated in the condenser 11 is removed from the first pressure reducing device 29.
And via the third solenoid valve 25 to replenish the hot gas cycle circuit. If in step 42 it is determined that the P _H> K _2, the process proceeds to step 44, it is determined whether the P _H> K ₃ (provided that K _3> K _2), determined that the P _H> K ₃ Then, it is determined that the amount of refrigerant in the hot gas cycle is excessive, and the routine proceeds to step 46, where the first solenoid valve 23 and the second solenoid valve 24 are opened and the third solenoid valve 25 is closed. As a result, the refrigerant of the hot gas cycle is taken into the condenser 11, and the amount of refrigerant circulating in the hot gas cycle is reduced. If in step 44 it is determined that the P _H ≦ K _3, the amount of refrigerant is determined to a proper amount, the first solenoid valve 23 proceeds to step 45 to close the third electromagnetic valve 25, the second solenoid valve Open 24. As a result, the bypass pipe 2 described above
Due to the hot gas cycle passing through 0, the heat of the refrigerant is radiated to the air by the evaporator 24 and complements the hot water heat radiation main heating by the heater core 3a. In this way, in order to control the excess or deficiency of the refrigerant amount flowing through the hot gas cycle by the combination of the switching operations of the first to third electromagnetic valves 23, 24, 25, the heat radiation amount from the evaporator 14 to the air is stabilized, A stable heating capacity can be secured.

A second embodiment of the present invention is shown in FIG. In the refrigerant circuit according to the second embodiment, in order to prevent the refrigerant circulating in the hot gas cycle from becoming an abnormally high pressure, instead of the third solenoid valve 25 used in the first embodiment, a reverse valve with a relief function is provided. The stop valve 30 is provided. The check valve 30 is provided, for example, between the receiver 12 and the first pressure reducing device 29.
It is arranged so that the refrigerant flows to the pressure reducing device 29 side. The check valve 30 is provided with a relief valve 30a that allows the refrigerant to escape to the receiver 12 side before the pressure of the refrigerant reaches, for example, the maximum pressure resistance value of the evaporator 14.

When the first solenoid valve 23 is closed and the second solenoid valve 24 is opened during heating, the refrigerant circulates in the hot gas cycle. At this time, when the ECU 32 determines that the amount of refrigerant is insufficient, the first electromagnetic valve 23 is opened, the second electromagnetic valve 24 is closed, and the refrigerant remaining in the condenser 11 is removed by the check valve 30.
To the hot gas cycle via. ECU 32
Is determined to be an excessive amount of refrigerant, both the first solenoid valve 23 and the second solenoid valve 24 are opened, and a part of the refrigerant circulating in the hot gas cycle is passed through the first solenoid valve 23 to the condenser 11 Miss to the side. When the pressure of the refrigerant circulating in the hot gas cycle rises abnormally and reaches the valve opening pressure of the relief valve 30a arranged in parallel with the check valve 30,
The high-pressure refrigerant flows through the first pressure reducing device 29, the check valve 30, and the receiver 12 in the direction opposite to that during cooling, and escapes to the condenser 11 side.

A third embodiment of the present invention is shown in FIG. The refrigerant circuit according to the third embodiment is provided with a superheat detection sensor 31 for detecting the degree of superheat from the temperature and pressure of the refrigerant between the evaporator 14 and the compressor 10. In this embodiment, the pressure sensor 33 is provided between the other end 20b of the bypass pipe 20 and the evaporator 14 so as to detect the refrigerant pressure on the inlet side of the evaporator 14.

During heating, the ECU 32 controls the first solenoid valve 23, the second solenoid valve 24, and the third solenoid valve 25 based on the detection signals of the pressure sensor 33 and the superheat detection sensor 31. In this case, when the superheat detection sensor 31 detects that the degree of superheat is high or when the pressure sensor 33 detects that it is lower than a predetermined pressure value, it is determined that the refrigerant amount is insufficient, the first solenoid valve 23 is opened, and the first solenoid valve 23 is opened. 2 solenoid valve 24
To close the refrigerant in the condenser 11 with the check valve 3
Supply to the hot gas cycle via 0. Further, when the pressure sensor 33 detects that the pressure value is higher than the predetermined pressure value, it is determined that the refrigerant amount is excessive, and the first solenoid valve 23 and the second solenoid valve 23
The solenoid valve 24 is also opened to allow a part of the refrigerant circulating in the hot gas cycle to escape to the condenser 11 side via the first solenoid valve 23. As a result, the amount of refrigerant circulating in the hot gas cycle is controlled to an appropriate amount, and abnormal high pressure of the refrigerant is reliably prevented.

In the first to third embodiments,
The heater core that uses the hot water for cooling the internal combustion engine as a heat source and the refrigerant (hot gas) that circulates in the refrigerant circuit are the heat sources for the main device and the auxiliary device of the present heating device. Of course, other heat sources may be used. Although the internal combustion engine was used as the drive source of the compressor, a voltage source may be used instead of this. Furthermore, in order to improve the controllability of the amount of refrigerant, a plurality of pressure sensors, superheat detection sensors, etc. may be provided in the refrigerant circuit as needed.

[0027]

As described above, according to the air conditioner of the present invention, a simple heating device using a high-temperature and high-pressure gas refrigerant in the refrigerant circuit is constructed, so this heating device is added to the main heating device. And since the heating capacity is improved, there is an effect that rapid heating becomes possible. Further, according to the air conditioner of the present invention, the amount of refrigerant circulating in the circuit of the high-temperature high-pressure gas refrigerant is controlled without excess or deficiency, so that the heating capacity of the auxiliary heating device can be exhibited in a stable state, and the durability of the compressor is improved. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a refrigerant circuit of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a partial Mollier diagram showing the refrigeration cycle according to the first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between suction pressure and compression power of the compressor used in the first embodiment of the present invention.

FIG. 4 is a flowchart showing a switching operation of solenoid valves of the air conditioner according to the first embodiment of the present invention.

FIG. 5 is a circuit diagram showing a refrigerant circuit of an air conditioner according to a second embodiment of the present invention.

FIG. 6 is a circuit diagram showing a refrigerant circuit of an air conditioner according to a third embodiment of the present invention.

[Explanation of symbols]

 1 Internal Combustion Engine 3 Hot Water Heater (Main Heating Device) 10 Compressor (Refrigerant Compressor) 11 Condenser 14 Evaporator (Heat Exchanger) 20 Bypass Pipe 20a Branch 20b Connection 22 Second Pressure Reduction Device (Pressure Reduction Device) 23 First Solenoid valve (first control valve) 24 second solenoid valve (second control valve) 25 third solenoid valve (third control valve) 29 first pressure reducing device 31 superheat detection sensor (control means) 32 ECU (control means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kinoshita 1-1-1, Showa-cho, Kariya city, Aichi prefecture

Claims (1)

[Claims] 1. An air conditioner including a main heating device, comprising a refrigerant compressor, a condenser connected to a discharge side of the refrigerant compressor, and a heat exchanger connected to an intake side of the refrigerant compressor. The heat exchanger provided in series with the main heating device so that the air flow passage flowing through the heat exchanger and the air flow passage heated by the main heating device at least partially coincide with each other, A first control valve provided in a path connecting the refrigerant compressor and the condenser, and a path connecting the condenser and the heat exchanger from the inlet side of the first control valve, bypassing the condenser Provided between the outlet side of the condenser and the connection portion of the bypass pipe, a decompression device provided in the middle of the bypass pipe, a second control valve provided in the middle of the bypass pipe, The third system A valve, a control means for releasing the refrigerant circulating in the refrigerant compressor, the bypass pipe, the pressure reducing device and the heat exchanger to the condenser side, and a control means for recovering the refrigerant from the condenser side. Air conditioner.