JPS62248963A - Air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to (1) an air conditioner equipped with a refrigeration cycle equipped with means for preventing an abnormal rise in the degree of superheating of the refrigerant at the outlet of the vaporizer;

[Prior Art] Compressor for compressing gas-phase refrigerant, condenser for liquefying compressed gas-phase refrigerant, receiver as temporary storage tank for refrigerant with gas/liquid separation function, pressure reducing device for atomizing liquid-phase refrigerant, and atomizing refrigerant In a refrigeration cycle configured by sequentially connecting two evaporators with refrigerant circulation piping, a preliminary decompression device is provided between the refrigerant and the receiver, and the gas phase refrigerant separated in the receiver is directly ] Install gas injection piping to circulate the gas to the Brezza.
A method has been used to improve the refrigerating capacity of refrigerated Nicle by forming a so-called gas injection cycle.

There is also a method of interposing a solenoid valve in this gas injection piping and closing the solenoid valve when the heat load is small to stop the gas injection cycle.
-112963J.

[Problems to be Solved by the Invention] When a refrigeration cycle equipped with a gas injection cycle as described above is used by incorporating it into an air conditioner for an automobile, the air conditioner generally uses a part of the output of the engine for driving the automobile. Since the engine is driven by the engine, the rotation speed of the engine must be varied very rapidly and over a wide range depending on the driving condition of the vehicle.

Considering the required pressure reducing function, it is sufficient to use a fixed restrictor such as Capillary 1-1, which has a simple structure and requires no maintenance, as a preliminary pressure reducing device to be interposed between the condenser and the receiver. It lacks the ability to instantaneously increase the amount of refrigerant passing through in response to a sudden increase in the refrigerant discharge pressure of the compressor.

Therefore, when the compressor rotation speed suddenly increases, the amount of refrigerant supplied to the evaporator becomes insufficient, resulting in a decrease in cooling capacity, and the degree of superheating of the refrigerant sucked into the combrella increases.
The humidity of the discharged refrigerant rises, which may cause damage to the equipment that makes up the refrigeration cycle or cause the engine to overheat.

The inventor of the present application has completed the present invention as a solution to such problems discovered in the conventional refrigeration cycle equipped with a gas injection cycle. It is an object of the present invention to provide an air conditioner equipped with a refrigeration cycle incorporating a mechanism for preventing various inconveniences as described above from occurring due to a sudden increase in rotational speed.

[Means for Solving the Problems] In order to solve the above problems, the air conditioner according to the present invention sequentially installs condensers in the refrigerant circulation path from the discharge port to the suction port of the compressor for compressing gas phase refrigerant. , a first pressure reducing device, a gas-liquid separator, a second pressure reducing device, and an evaporator are interposed, and a gas injection pipe is attached for directly circulating the gas phase refrigerant separated by the gas-liquid separator to the suction port. In an air conditioner equipped with a refrigeration cycle, a means for controlling the flow of refrigerant flowing through the gas injection pipe, and information on a refrigerant temperature related to the degree of superheating of the refrigerant at the outlet of the evaporator or information related to a sudden increase in the rotational speed of the compressor. Abnormal overheating detection means for detecting abnormal heating, and abnormal overheating prevention means for operating the flow control means based on information from the abnormal overheating detection means to stop or suppress the operation of the gas injection. Adopted.

[Operation and Effects of the Invention 1] In the air conditioner having the above configuration, the rotational speed of the refrigerant compressor increases rapidly with changes in the output of the compressor driving motor, and the refrigerant is overheated at the outlet of the evaporator. When the temperature is about to rise above a set level, the abnormal overheat detection means detects or predicts this and notifies the abnormal overheat prevention means.

Based on this notification information, the abnormal overheating prevention means activates the flow rate control means interposed in the gas injection piping.
This will stop or reduce the flow of refrigerant into this pipe.
The fear of insufficient refrigerant supply to the evaporator is eliminated, and abnormal refrigerant superheating at the outlet of the evaporator is prevented.

Once the sudden acceleration of the compressor's rotational speed is resolved, the information notification signal from the abnormal overheat detection means stops, and the flow rate control means operates to fully operate the gas engine, improving the refrigeration capacity of the refrigeration cycle. do.

[Example] The structure of the present invention will be specifically described below based on the example shown in the attached drawings.

FIG. 1 is a schematic system diagram illustrating a configuration in which the device of the present invention is applied to a refrigeration cycle of an automobile air conditioner.

Reference numeral 1 denotes a compressor for compressing gas-phase refrigerant, and in this embodiment, a swash plate type compressor υ containing 10 compression cylinders is used. Two suction ports 1a and 1b and 1
It has two discharge ports 1C. The suction portions of most of the ten cylinders, for example nine cylinders, are connected to the suction port 1a, and the suction portion of the remaining one cylinder is connected to the suction port 1b. The discharge portions of each of the ten cylinders are configured to gather at the discharge port 1C.

A magnetic clutch 21 is attached to the rotating shaft of the compressor 1 for transmitting the rotational force of a vehicle running engine 20 as a power source for driving the compressor in an intermittent manner. 22 to 24 are the bobbles and V- for transmitting rotational force.
It's a belt.

The refrigerant circulation pipes a to G between the discharge port 1C and the suction port 1a of the compressor 1 include a condenser 2 for liquefying the compressed gas phase refrigerant, a first pressure reducing device for reducing the pressure of the refrigerant, and a capillary capillary in this embodiment. Yup 3, a gas-liquid separator (receiver) that plays the role of gas-liquid separation and temporary storage of liquid phase refrigerant 4
, a second pressure reducing device for reducing the pressure of the liquid refrigerant and atomizing it; and a temperature-operated expansion valve 5 in this embodiment; In addition, an evaporator 6 is interposed in order to cool the air by removing the latent heat of vaporization when the refrigerant vaporizes from the air.

The upper part of the receiver 4 as a closed container is connected to the downstream @ 4a of the piping connected to the capillary duplex 3, and the gas phase refrigerant separated from the liquid phase refrigerant in the receiver is
An upstream end 1a of a gas injection pipe 7 is attached to allow the gas to circulate directly to the compressor 1 without passing through the vaporator 6. Near the bottom of the receiver 4 is an upstream end 4 of a refrigerant pipe connected to the temperature-operated expansion valve 5.
b is located in a state where it is immersed in a liquid phase refrigerant.

The downstream end of the gas injection pipe 7, which forms a bypass return path for the gas phase refrigerant, is connected to the suction port 1b of the compressor 1, and a solenoid valve 8 is interposed in the middle of this pipe as a means for controlling the flow rate of the refrigerant passing through. There is. 9 is a solenoid coil for opening and closing the electromagnetic valve.

The electromagnetic valve 8 is an abnormal overheat detection means for detecting that the degree of superheat of the refrigerant at the outlet of the evaporator 6 exceeds a set level, and in this embodiment, the degree of superheat of the refrigerant at the outlet of the evaporator 6 is detected. Abnormal overheating prevention means that receives temperature information from thermistors 12 and 11 for measuring Lf1 degree, in this case, the operation control device 1 of the air conditioner
The valve is closed only when abnormal overheating is detected by the operation of an electronic control circuit 30 built into the valve, and the valve is normally kept open.

FIG. 3 shows a specific example of an electronic control circuit 30 for opening and closing the solenoid valve 8 as an example of abnormal overheat prevention means.

31 is a constant pressure diode, 32 is a variable resistor for selectively determining at what level the degree of superheating of the refrigerant at the outlet of the evaporator 6 has increased to activate the abnormal overheat prevention means, 33 is a comparator, 35 34 is an on-oran transistor for energizing the excitation coil of the relay 35, and 40 is a battery mounted on the vehicle.

FIG. 2 is a perspective view specifically depicting the overall configuration of the refrigeration cycle shown in FIG. 1.

Next, the operation of the above-mentioned embodiment device will be described first under normal operating conditions, that is, when the rotational speed of the engine driving the compressor does not suddenly rise and the degree of superheat of the refrigerant at the outlet of the evaporator 6 does not rise significantly beyond the set level. The case under the condition will be explained.

The gas phase refrigerant discharged from the evaporator 6 after completing the refrigeration work is sucked into the first suction port 1a of the conbrella +1, compressed to high temperature and pressure, and then pushed out from the condenser 1C and passed through the condenser 2. During this time, the vehicle is cooled by a radiator cooling fan (not shown) and by airflow from the vehicle.

The liquid-phase refrigerant then passes through a capillary tube 3 serving as a first pressure reducing device, and is subjected to a preliminary pressure reducing action, causing a portion to vaporize, thereby reducing its enthalpy.

The gas-liquid phase mixed refrigerant is transferred to the receiver 4 which has a gas-liquid separation function.
The liquid refrigerant is temporarily stored inside the refrigerant.

The gas phase refrigerant separated from the mixed phase is transferred to the upstream end 7a of the gas injection pipe 7 connected to the top of the receiver 4.
The air flows into this pipe, passes through the normally open electromagnetic valve 8, reaches the downstream end, and is sucked into the second suction port 1b of the compressor 1.

Therefore, the vapor phase refrigerant generated in the first pressure reducing device or not completely liquefied in the condenser, which is completely useless for the refrigeration work, is further increased in volume by the downstream second pressure reducing device, and becomes useless. The inconvenience of placing a burden on the compressor 1 can be avoided.

The liquid phase refrigerant once stored in the receiver 4 is sent into the evaporator 6 in an amount corresponding to the opening degree of the expansion valve 5 due to the pressure gradient within the piping system. When the liquid phase refrigerant passes through the expansion valve 5, it is depressurized and becomes atomized.

Since the evaporator 6 is blown with high-temperature conditioned air by the blower of the air conditioner (not shown), the atomized refrigerant removes the latent heat of vaporization from this air, cools it, and achieves the desired temperature. Refrigeration work is accomplished.

The expansion valve 5 adjusts its opening degree as the pressure of the gas sealed in the heat-sensitive cylinder 13 that senses the humidity of the refrigerant at the outlet of the evaporator 6 fluctuates depending on the temperature, and adjusts the degree of superheating of the refrigerant at the outlet of the evaporator 6. is always kept constant. Here, the degree of superheating refers to the temperature difference between the saturated moisture content (boiling point) of the refrigerant and the temperature of the superheated refrigerant vapor (refrigerant vapor in a heated state, consisting only of the gas phase). means.

The refrigerant that has completely returned to the gas phase by passing through the evaporator 6 is sucked into the first suction port 1a of the compressor 1, and is compressed separately from the refrigerant that has flowed into the second suction port 1b. 1C and merge, starting the next wi ring cycle.

Next, when starting the engine 20, accelerating greatly while driving, or racing, the rotation speed of the compressor is suddenly reduced, but the capillary duplex 3 as the first pressure reducing device The cross-sectional area of the liquid passage is 1 ft.
Since there is no means to increase or decrease it to follow the fluctuations in
In the refrigerant circulation piping system a-C, a so-called damming up of the refrigerant occurs at the tip of the pipe tube 3, making it impossible to replenish the amount of refrigerant required by the evaporator 6. As the degree of shortage of refrigerant supply increases, the refrigerating capacity of the device naturally decreases.In addition, when the refrigerant supply to the evaporator 6 becomes insufficient, the degree of superheating of the refrigerant at the outlet becomes as described above. The temperature gradually increases beyond a predetermined level, resulting in an abnormal heating state. Then, the degree of superheating of the refrigerant sucked into the compressor increases, and the rise in the rate of refrigerant discharge increases the risk of heat embrittlement of parts constituting the refrigeration cycle and the risk of the engine overheating.

However, in the apparatus of the above embodiment, refrigerant temperature detection sensors 12 and 11 are installed at the inlet and outlet of the evaporator 6, respectively, as means for detecting or predicting this abnormal overheating.

Now, when the rotational speed of the engine 20 suddenly increases, the degree of superheat at the outlet of the evaporator 6 increases abnormally due to the above-mentioned reason. However, in the opening/closing control circuit for the solenoid valve 8 shown in FIG. 3, the refrigerant temperatures at the inlet and outlet of the evaporator 6 detected by the sensors 12 and 11, respectively, are compared and the difference therebetween reaches, for example, 30°C or more. Comparator 33
If the resistance value of the variable resistor 32 is set so as to produce an output from the output, when this temperature difference exceeds 30°C due to an abnormal overheating phenomenon, the transistor 34, which performs the switching function, is turned on. The contact of the relay 35 for closing the normally open solenoid valve 8 is turned on.

By operating the relay 35 and closing the solenoid valve 8, the flow of the gas phase refrigerant into the gas injection pipe 7 is stopped, so that the contact interface between the gas phase refrigerant and the liquid phase refrigerant in the receiver 4 is The gas-liquid equilibrium relationship is lost, and the capillary tube 3 no longer performs the vaporizing action of the refrigerant.

Therefore, the flow resistance when the refrigerant passes through the capillary tube 3 is greatly reduced, and the fear of insufficient refrigerant supply to the evaporator 6 is eliminated. Accordingly, the degree of superheat at the outlet of the evaporator 6 is reduced to a normal level,
The difference in refrigerant thirst between the inlet and outlet of evaporator 6 is 30°C
When the value is below, the output signal from the comparator 33 stops, the solenoid valve 8 opens, and the gas injection cycle is restarted.

The electronic control circuit as an example of the abnormal overheat prevention means can have various circuit configurations in addition to the one shown in FIG.

In the above embodiment, a method of detecting the temperature difference of the refrigerant at the inlet and outlet of the T-vaporator 60 was described as a means for predicting abnormal overheating. When the temperature exceeds .degree. C., the solenoid valve 8 may be closed based on this temperature information. Further, the refrigerant pressure sensor 18 provided at the outlet of the evaporator 6 may be used in combination with the temperature sensor 11 as means for predicting abnormal overheating.

A liquid level resistor 17 is built into the receiver 4 as a gas-liquid separator as a means for predicting abnormal overheating, and when the liquid level falls below a set level, the solenoid valve 8 is closed or the liquid refrigerant expands from the liquid phase refrigerant outlet of the receiver 4. A refrigerant dryness sensor 16 is connected to the valve 5.
A refrigerant temperature sensor or a refrigerant pressure sensor 1 may be installed at the discharge port of the compressor.
5 may be attached. A refrigerant dryness sensor has a structure in which a fluid to be measured is caused to flow between a pair of electrodes by utilizing a phenomenon in which the energization rate of a gas-liquid mixed fluid changes depending on the gas content.

Furthermore, the reason why the degree of superheating of the refrigerant at the evaporator outlet abnormally increases is often due to a sudden increase in the rotation speed of the compressor 1; A sensor that detects the acceleration of a vehicle, a vehicle running acceleration sensor, or a pressure sensor in the intake pipe of a running engine can also be used as the abnormal overheat detection means.

The refrigeration cycle shown in FIG. 1 to be incorporated into the apparatus of the present invention is merely an embodiment of the present invention. For example, the refrigerant flow rate control means is not limited to a solenoid valve, The valves may be equipped with an opening/closing mechanism. Further, the first and second pressure reducing devices are not limited to the structure shown in the drawings, and for example, a constant pressure expansion valve or an electric expansion valve may be used as the second pressure reducing device. In the latter case, opening/closing control is performed so that the difference in temperature of the refrigerant reported from the masters 12 and 11 is always constant.

When changing the design of the refrigerant circulation piping in various ways,
For example, the configuration of the present invention can also be effectively incorporated into a refrigeration cycle that is switched to a heat pump cycle. Furthermore, the method of controlling the flow rate of the refrigerant is not necessarily limited to the two operating modes of fully opening and fully opening the flow path, but may be such that an intermediate operating mode between these two operating modes can be adopted.

[Brief explanation of drawings]

Figure 1 is a cycle diagram illustrating the configuration of the refrigeration cycle incorporated in the device of the present invention, Figure 2 is a perspective view illustrating the specific configuration of the refrigeration cycle shown in Figure 1, and Figure 3 is an abnormality. It is an electronic control circuit diagram as an example of an overheat prevention means. In the diagram 1... Compressor 2... Capacitor 3
...First pressure reducing device 4... Gas-liquid separator 5... Second pressure reducing device 6... Evaporator 7... Gas injection piping 8... Refrigerant flow rate control means (electromagnetic valve) 11.12 ... Abnormal overheat detection means (thermistor)
20... Vehicle running engine 21... Magnetic clutch 30... Abnormal overheating prevention means

Claims (1)

[Claims] 1) A condenser, a first pressure reducing device,
Air equipped with a refrigeration cycle that includes a gas-liquid separator, a second pressure reducing device, and an evaporator, and is equipped with a gas injection pipe for directly circulating the gas-phase refrigerant separated by the gas-liquid separator to the suction port. The conditioning device includes: a flow control means for refrigerant flowing through the gas injection pipe; and abnormal heating for detecting refrigeration cycle information related to the degree of superheating of the refrigerant at the outlet of the evaporator or information related to a sudden increase in the rotational speed of the compressor. An air conditioner comprising: a detection means; and an abnormal overheat prevention means for operating the flow control means based on information from the abnormal overheat detection means and stopping or suppressing operation of the gas injection. . 2) The abnormal overheat detection means comprises a refrigerant temperature sensor provided at an inlet and an outlet of the evaporator, and a comparison circuit for comparing the temperatures detected by both temperature sensors. Air conditioner. 3) The air conditioner according to claim 1, wherein the abnormal overheating detection means is a refrigerant temperature sensor provided at the outlet of the evaporator. 4) The air conditioner according to claim 1, wherein the abnormal overheating detection means is a refrigerant pressure sensor provided at the outlet of the evaporator. 5) The air conditioner according to claim 1, wherein the abnormal overheating detection means is a refrigerant temperature sensor provided at a discharge port of the compressor. 6) The air conditioner according to claim 1, wherein the abnormal overheat detection means is a refrigerant pressure sensor provided at a discharge port of the compressor. 7) The air conditioner according to claim 1, wherein the abnormal overheat detection means is a liquid level sensor provided in the gas-liquid separator. 8) The air conditioner according to claim 1, wherein the abnormal overheat detection means is a refrigerant dryness sensor provided on the outlet side of the gas-liquid separator. 9) The air conditioner according to claim 1, wherein the abnormal overheating detection means is an acceleration sensor that detects rotational acceleration speed of the compressor.