JP3060444B2 - Air conditioner - Google Patents

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 an apparatus 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 apparatus switches to a defrosting operation when the evaporator is blocked by frost during the cooling operation, melts the frost of the evaporator, and forms a cycle in which the refrigerant is returned to the compressor via the accumulator in a gaseous state.

As a conventional air conditioner mounted on a vehicle, a hot water heater utilizing the exhaust heat of cooling water of an internal combustion engine for running the vehicle is used. For example, as shown in FIG. The cooling hot water is introduced into the heater core 3a of the hot water heater 3 by the pipe 2, and the cooling hot water radiated by the heater core 3a is returned to the internal combustion engine 1 by the pipe 4. The hot water heater 3 is provided on the downstream side of the heat exchanger 14 constituting the cooling device with respect to the flow of air guided into the vehicle interior.

In a conventional air conditioner in which such a hot water heater is used as a main heating device, an electric heater, a combustion heater, a heat pump, or the like is used as an auxiliary heating device for supplementing the heating capacity of the main heating device. It is known.

[0005]

However, according to such a conventional air conditioner, the aforementioned Japanese Patent Publication No. 57-478 is disclosed.
The device disclosed in Japanese Patent Publication No. 29 is a device for removing frost during a cooling operation by using a high-temperature gas, and does not increase the heating capacity at the time of heating. In addition, a heating device using the exhaust heat of the cooling water of the internal combustion engine for running the vehicle as a heat source,
Since the temperature of the cooling water is low when the internal combustion engine is started at a low temperature, there is a problem that the startup of the hot water heater that uses the cooling water as a heat source is poor.

Further, as described above, an air conditioner using an electric heater, a combustion heater, and a heat pump in combination with an auxiliary heating device has a problem that the startup of the hot water heater is poor when the internal combustion engine is started at a low temperature as described above. In the case of using a heater together, there is a problem that power shortage easily occurs.
Those using a combustion heater in combination have a problem that the safety tends to deteriorate, and those using a heat pump in combination have a problem that use in a cold region becomes impossible.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and uses a high-temperature and high-pressure gas refrigerant (hot gas) in a refrigeration cycle to improve the heating start-up capability at the initial stage of air conditioning. It is intended to provide an air conditioner.

[0008]

According to a first aspect of the present invention, there is provided an air conditioner for use in a vehicle.
A refrigerant compressor, through a pipe to the discharge side of the refrigerant compressor
A capacitor connected to a heat exchanger which is connected via a pipe to the suction side of the refrigerant compressor, bypassing the condenser and the condenser inlet and the heat exchanger inlet side <br/> A first bypass pipe connected to a piping path connecting the first compressor , a first pressure reducing device provided in the first bypass pipe, a refrigerant compressor outlet side and a refrigerant compressor inlet side bypassing the condenser. And a second bypass pipe connected to a piping path connecting the refrigerant compressor and the condenser compressor.
Switching position where the refrigerant flows, the first position from the refrigerant compressor
Switching position where the refrigerant flows toward the bypass pipe of
The refrigerant flows from the medium compressor toward the second bypass pipe.
And a switch valve for switching a refrigerant flow path that switching position, before
When the heating is initially started, the on-off valve is turned on by the second bypass.
It opens and closes so that the refrigerant flows through the heat pipe, and at a certain time from the start of heating
Elapses or the pressure of the refrigerant compressor reaches a constant pressure.
Then, the second bypass pipe is closed and the first bypass is closed.
It is characterized in that it opens and closes so that the refrigerant flows through the pipe . Book
The air conditioner according to claim 2 of the present invention is arranged such that the refrigerant compressor is
The accumulator installed in the pipe between the heat exchangers
It is characterized by having. An air conditioner according to claim 3 of the present invention.
According to the device, the on-off valve is connected to the refrigerant compressor outlet side.
A pipe installed in the pipe route connecting the condenser inlet side
One solenoid valve and a second solenoid valve provided in the first bypass pipe.
And a third valve provided in the second bypass pipe.
And a solenoid valve.

[0009]

According to the air conditioner of the present invention, for example, at the time of heating at the time of low-temperature start of the internal combustion engine, for example, as shown in FIG. Heat is dissipated in the heat exchanger. Then, at the time of the initial rise of heating, the on- off valve allows the refrigerant to flow through the second bypass pipe.
By passing the refrigerant to the second pressure reducing device of the second bypass pipe opening to the on so that the refrigeration cycle is a closed circuit according to the second hot gas bypass mechanism, the pressure of the cycle is rapidly increased, the compressor The compression work soars. Next, after the initial rise of heating, that is, at a certain time from the start of heating
Elapses or the pressure of the refrigerant compressor reaches a constant pressure.
Then, the on-off valve closes the second bypass pipe and the
The refrigeration cycle is switched to a closed circuit by a first hot gas bypass mechanism that passes through the first decompressor of the first bypass pipe by opening and closing so that the refrigerant flows through the first bypass pipe. Then, although there is a temporary decrease in heating due to the heat capacity of the heat exchanger and latent heat of the refrigerant, the compression work of the compressor is already large, so that the heating capacity in the initial stage of air conditioning is improved, and rapid heating becomes possible. . Further, the refrigerant compressor and the heat exchanger
Gas and liquid by installing an accumulator in the pipe between
The separation performance can be improved and the liquid back can be prevented.

[0010]

Embodiments of the present invention will be described below 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. The main heating device of the vehicle uses a heater core that uses hot water for cooling the internal combustion engine as a heat source. As shown in FIG. 1, a refrigerant circuit of an air conditioner using a hot gas refrigerant that assists the main heating device includes a compressor 10 driven by an internal combustion engine, a condenser 11, a receiver 12, a check valve 9, a pressure reducing device, 13, heat exchanger 14, accumulator 1
5 are connected in order by a pipe 16. The first solenoid valve 1 provided between the compressor 10 and the condenser 11
One end 20a of a first bypass pipe 20 that bypasses the condenser 11 is connected between the compressor 7 and the compressor 10, and the other end 20b of the first bypass pipe 20 is connected between the pressure reducing device 13 and the heat exchanger 14. To the piping 16. First bypass pipe 20
Is provided with a first pressure reducing device 22. The second solenoid valve 18 is provided between the first pressure reducing device 22 and one end 20a of the first bypass pipe 20.

[0011] appropriate pressure gas refrigerant is controlled by the first pressure reducing device 22, first at the high pressure side of the pressure reducing device 22 15 kg / cm ² or more, 2-4 kg / cm ² in the low-pressure side
It is. This is because when the outside air temperature is low, the pressure on the high pressure side is kept high in order to obtain sufficient heating capacity because the temperature on the low pressure side is also low, and as shown in FIG. This is because the pressure on the high pressure side of the first pressure reducing device 22 must be increased to 15 kg /
cm ² or more is desirable.

A check valve 9 is provided in a pipe 16 between the receiver 12 and the pressure reducing device 13. The check valve 9 prevents the refrigerant from flowing back to the condenser 11 and becoming short of the refrigerant.
The accumulator 15 stores the refrigerant when the refrigerant becomes excessive, prevents the liquid from returning to the compressor 10, and always circulates the hot gas refrigerant in the refrigerant circuit. The second bypass pipe 40 has one end connected in the middle of a pipe connecting the compressor 10 to the first solenoid valve 17 or the second solenoid valve 18, and the other end connected to the accumulator 15 and the compressor 10. And is connected in the middle of the pipe connecting them.
In the middle of the second bypass pipe 40, a third solenoid valve 41 and a second pressure reducing device 42 are provided. First solenoid valve 1
The control device 100 controls opening and closing of the seventh, second electromagnetic valve 18 and third electromagnetic valve 41.

The configuration block diagram of the control system is as shown in FIG. The internal combustion engine is provided with a water temperature sensor 102 for detecting a water temperature, a thermistor 103 for detecting an air temperature is provided near an air outlet of the heat exchanger 14, and a compressor 10 and a first bypass pipe 20 are provided.
A pressure sensor 104 for detecting a refrigerant pressure in the pipe is attached to the pipe between the first end 20a and the other end 20a. Input device 10
Reference numeral 1 denotes a device for inputting driving and stopping of cooling and driving and stopping of heating. The output of the water temperature sensor 102, the thermistor 103, the pressure sensor 104, and the input device 101
00, the output of the controller 100 controls the compressor 10, the first solenoid valve 17, the second solenoid valve 18, and the third solenoid valve 41.

Here, the thermistor 103 detects the air temperature after the heat exchanger 14 during cooling. Control device 100
Determines the freezing of the heat exchanger 14 based on the air temperature detected by the thermistor 103.
Stop 0. Thereafter, when the air temperature detected by the thermistor 103 rises and there is no fear of freezing, the compressor 1
0 operation is resumed. Since the heat exchanger 14 does not freeze during heating, the compressor 10 does not stop based on the detection signal of the thermistor 103.

The pressure sensor 104 detects the refrigerant pressure in the refrigerant cycle. During cooling, the control device 100 determines that the pressure detected by the pressure sensor 104 is abnormal even if the pressure is within or below a predetermined pressure range for device protection, and stops the compressor 10. Thereafter, when the pressure detected by the pressure sensor 104 falls within a predetermined range, the operation of the compressor 10 is restarted. During the heating, the outside air temperature is low, so that the refrigerant pressure may drop below the above-mentioned pressure range. However, since there is no fear that the heat exchanger 14 freezes, it is not determined that the temperature is below the predetermined pressure range.

The water temperature sensor 102 detects a cooling water temperature of the internal combustion engine. Whether or not a radiator (not shown) for supplying cooling water is radiating heat depends on whether hot water is flowing through the radiator,
Alternatively, the determination is made based on whether hot water flows through the bypass pipe that bypasses the radiator and does not flow into the radiator.
At the time of heating, when control device 100 determines that the state of the radiator is heat radiation, compressor 10 is stopped. The fact that the radiator is in a heat radiation state means that the heat that could not be radiated by the heater core is radiated by the radiator.Conversely, sufficient heat is radiated by the heater core, so auxiliary heating is required. And not. Thereafter, when the cooling water temperature detected by the water temperature sensor 102 decreases and the heat is no longer released, the operation of the compressor 10 is restarted. The control by the water temperature sensor 102 is performed only during heating.

During cooling, the first solenoid valve 17 is opened, the second solenoid valve 18 and the third solenoid valve 41 are closed, and the compressor 1
0 flows only to the condenser 11 side, and the compressor 1
The refrigerant from 0 circulates in the order of the condenser 11, the receiver 12, the pressure reducing device 13, the heat exchanger 14, the accumulator 15, and the compressor 10. During heating, each solenoid valve is opened and closed as follows according to the flowchart shown in FIG. As shown in FIG. 5, first, initialization is performed in step 51. In the initial setting, the first solenoid valve 17 is opened, the second solenoid valve 18 is closed, and the third solenoid valve 41 is closed. After the start of heating, step 52
As shown in (2), the second solenoid valve 18 is closed and the third solenoid valve 41 is opened. Then, the refrigerant discharged from the compressor 10 is
The gas passes through the second bypass pipe 40 and is sucked into the compressor 10 again. At this time, since the second pressure reducing device 42 is provided in the middle of the second bypass pipe 40, the discharge pressure of the compressor 10 increases, thereby warming up. Next, as shown in step 53, when it is determined that a certain time has elapsed or a certain pressure has been reached, it is determined that the warm-up has ended. Then, at step 54, the second solenoid valve 18 is opened and the third solenoid valve 41 is closed. Thereby, steady heating is performed in step 55, and the refrigerant discharged from the compressor 10 passes through the first bypass pipe 20, radiates heat in the heat exchanger 14, and is sucked into the compressor 10 again. Next, when a heating stop is requested, the heating is stopped in step 56.

FIG. 2 is a Mollier diagram showing changes in the refrigerant during steady heating. That is, the first solenoid valve 17 is closed, the second solenoid valve 18 is open, and the third solenoid valve 41
Is closed, the high-temperature and high-pressure gas refrigerant compressed by the compressor 10 changes from the low pressure P _L to the high pressure P _H , and when passing through the first pressure reducing device 22, the gas pressure changes from the high pressure P _H It falls to a low pressure P _L , enters the heat exchanger 14 and passes through an accumulator 15 to the inlet side of the compressor 10.

The compression work by the compressor 10, as shown in FIG. 4, the pressure on the outlet side of the compressor 10 is a high pressure P _H, and the
The pressure P _H that is 15 kg / cm ² or more desirable. When the suction pressure of the compressor 10 is in the range of 1 to 5 kg / cm ² , the discharge pressure (high pressure P _H ) at the compressor outlet side is 15 kg / c.
This is because the compression power becomes larger when m ² or more.

According to this embodiment, since the compressor 10 is driven by the internal combustion engine, the load of the internal combustion engine increases, and the heat generated in the internal combustion engine is transmitted to the cooling hot water, and the heat of the cooling hot water is transmitted to the heater core. The blowing temperature is increased, and the heating capacity of the heater core is also increased. Accordingly, the air is heated by the high-temperature and low-pressure hot gas refrigerant in the heat exchanger 14, and the heated air is further heated to a higher temperature by removing heat from the internal combustion engine cooling hot water by the heater core. Therefore, the heating capacity of the air conditioner is considerably increased. This enables an increase in heating capacity and rapid heating.

At the time of stoppage, the first solenoid valve 17 and the second solenoid valve 18 are switched so that the first bypass pipe 20 is opened on the heating side during cooling and heating, and then stopped. The reason is that the condenser 11 and the receiver 12 are in a hermetically closed state during heating, and if a large amount of refrigerant exists in this portion, the cycle may run out of refrigerant during heating.
When stopped, the first solenoid valve 17 and the second solenoid valve 18 are switched to the heating side to seal the condenser 11 and the receiver 12, so that the refrigerant does not flow into the condenser 11 and the receiver 12 from other parts. This is because it is possible to secure a necessary refrigerant at the time of heating.

During the heating control, after the operation of the compressor 10 is stopped,
When the abnormality of the refrigerant pressure and the cooling water temperature is resolved, the compressor 1
Although the operation of the compressor 10 is restarted, the operation of the compressor 10 does not need to be restarted when the operation of the compressor 10 is used only for improving the rising performance of heating. In the first embodiment, the check valve 9 may be an electromagnetic valve or may be used also as the pressure reducing device 13. Also,
Instead of the thermistor 103, another temperature sensor such as a thermostat may be used. Instead of the thermistor signal, the surface temperature of the heat exchanger 14 may be detected. Further, the mounting position of the pressure sensor 104 may be provided at the high pressure portion of the bypass pipe 20 instead of the position of the first embodiment. In this case, a dedicated pressure sensor for heating can be used.
Further, the stop of the compressor 10 may be directly used as a switch without depending on the control device 100. A new water temperature cut can be performed without performing low pressure cut and frost cut of the air conditioner during heating and cooling.

In the first embodiment, the second solenoid valve 18 is closed and the third solenoid valve 41 is opened after heating is started.
As a control method according to another embodiment, the solenoid valve may be controlled as in a control flow according to the second embodiment shown in FIG.
According to the second embodiment, at the time of initial setting in step 61, the first solenoid valve 17 is closed, the second solenoid valve 18 is closed, and the third solenoid valve 41 is set to open. The passage of time or the arrival of a constant pressure is determined, and the solenoid valves 17, 18, 41 are brought to the initial state until it reaches that point. That is, the first solenoid valve 17 is closed, the second solenoid valve 18 is closed, and the third solenoid valve 41 is opened. Next, when it is determined in step 62 that a predetermined time has elapsed or a predetermined pressure has been reached, the warm-up is terminated, the flow proceeds to step 63, the second solenoid valve 18 is opened, and the third solenoid valve 41 is closed. To
Thereby, the steady heating shown in step 64 is performed. Thereafter, when the heating is completed, the heating is stopped as shown in step 65. After the heating is stopped, the second solenoid valve 18 is closed and the third solenoid valve 41 is opened as shown in step 66.

Also in the second embodiment, as in the first embodiment, the refrigerant pressure is rapidly increased to warm up the hot gas cycle circuit, thereby increasing the heating capacity at the beginning of heating. Next, a refrigerant circuit according to a third embodiment of the present invention is shown in FIG. In the third embodiment, the second
One end of the bypass pipe 40 is connected in the middle of a pipe connecting the heat exchanger 14 and the accumulator 15.
Thereby, at the time of warm-up, the refrigerant decompressed and discharged from the second decompression device 42 is gas-liquid separated by the accumulator 15, and only the gas phase of the refrigerant is sucked into the compressor 10, so that the compression efficiency can be increased.

The above embodiment is an example in which the present invention is applied to a car cooler of a vehicle air conditioner. However, except for components used only for cooling, such as the condenser 11 and the receiver 12 in the above embodiment, a hot gas cycle is used. Only auxiliary heating may be used. Further, the receiver 12 and the accumulator 15 of the above embodiment are both devices for adjusting the refrigerant amount, but the refrigerant amount may be adjusted in either the receiver 12 or the accumulator 15, and the refrigerant charge amount can be separately managed. If so, the receiver 12 and the accumulator 15 may be omitted. Further, in the above embodiment of the present invention, the drive source of the compressor 10 is an internal combustion engine, but a voltage source may be used instead. Further, instead of the first solenoid valve 17 and the second solenoid valve 18, other switching means such as a three-way valve arranged at a branch point of the bypass pipe may be used.

According to the experimental data, the relationship between the elapsed time after the start of heating and the heater outlet temperature is as shown in FIG. As shown in FIG. 7, compared to Comparative Examples 1 and 2, according to the first embodiment of the present invention, the heater outlet temperature can be sharply increased at the time of initial heating, and the heating start-up ability at the initial time can be improved. it can. Here, Comparative Example 1 is a heating device using only a heater core without using a hot gas refrigerant circuit, and Comparative Example 2 is a heating device using a hot gas refrigerant circuit without the second bypass pipe 40. .

[0027]

As described above, according to the air conditioner of the present invention, a simple heating device using the high-temperature and high-pressure refrigerant gas of the refrigeration cycle is constituted. Not only is the heating capacity increased, but also at the beginning of heating, the refrigerant discharged from the compressor is decompressed and expanded through the second decompression device, and the decompressed refrigerant is sucked into the compressor and discharged again. Therefore, there is an effect that the pressure of the hot gas cycle is rapidly increased, and the heating initial rising ability can be greatly improved.

[Brief description of the 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 a refrigeration cycle according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a control system of the present invention.

FIG. 4 is a characteristic diagram showing a relationship between a suction pressure and a compression power of a compressor used in the first embodiment of the present invention.

FIG. 5 is a flowchart showing a heating control flow according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing a heating control flow according to a second embodiment of the present invention.

FIG. 7 is a characteristic diagram comparing an air-conditioning apparatus according to a first embodiment of the present invention with an air-conditioning apparatus according to a conventional comparative example in terms of initial heating start-up capacity.

FIG. 8 is a circuit diagram showing a refrigerant circuit of an air conditioner according to a third embodiment of the present invention.

FIG. 9 is a circuit diagram showing a conventional refrigerant circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Compressor (refrigerant compressor) 11 Condenser 14 Evaporator (Heat exchanger) 17 1st electromagnetic valve 18 2nd electromagnetic valve 20 1st bypass pipe 22 1st decompression device 40 2nd bypass pipe 41 3rd Solenoid valve 42 of the second pressure reducing device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-17081 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 13/00 361

Claims (3)

(57) [Claims] 1. A refrigerant compressor used in a vehicle, a capacitor connected via a pipe to the discharge side of the refrigerant compressor, a heat exchanger which is connected via a pipe to the suction side of the refrigerant compressor When a first bypass pipe connected to the pipe path connecting said condenser inlet side to bypass the condenser and the heat exchanger inlet side, a first pressure reducing device provided in the first bypass pipe A second bypass pipe connected to a pipe route that connects the outlet side of the refrigerant compressor and the inlet side of the refrigerant compressor, bypassing the condenser; and a second decompression device provided in the second bypass pipe And the refrigerant flows from the refrigerant compressor toward the condenser.
Switching position, from the refrigerant compressor to the first bypass pipe
From the switching position and the refrigerant compressor where the refrigerant flows toward
In the switching position where the refrigerant flows toward the second bypass pipe
An opening / closing valve for switching a refrigerant flow path , wherein the opening / closing valve is connected to the second bypass when the heating is initially started.
Opens and closes so that refrigerant flows through the pass tube, and is constant from the start of heating
After a lapse of time or the pressure of the refrigerant compressor reaches a certain pressure
Then, the second bypass pipe is closed and the first bypass pipe is closed.
An air conditioner, which opens and closes so that a refrigerant flows through a pipe . 2. An arrangement between the refrigerant compressor and the heat exchanger.
Characterized by having an accumulator installed in the pipe
The air conditioner according to claim 1. 3. The on-off valve is connected to an outlet side of the refrigerant compressor.
A pipe installed in the pipe route connecting the condenser inlet side
One solenoid valve and a second solenoid valve provided in the first bypass pipe.
And a third valve provided in the second bypass pipe.
3. A solenoid valve according to claim 1, wherein the solenoid valve is a solenoid valve.
Air conditioner.