JPH07332807A - Suprecooling control valve and refrigeration cycle - Google Patents

Abstract

PURPOSE:To achieve the optimum supercooling in order to attain a nearly maximal cycle efficiency by a method wherein the degree of valve opening is controlled based on the difference between the inner pressure of one pressure chamber which varies according to the change of the temp. of the air sucked into a room condenser and the inner pressure of the other pressure chamber which varies according to the change of the temp. of the refrigerant at the outlet. CONSTITUTION:A valve body 225 is disposed downstream of a throttling hole 231 in the inner space of a valve housing 220 and a displacement is transmitted to a diaphragm 224 via a stopper 237 and a rod 239 connected thereto. A spring 226 is disposed between the valve body 225 and an adjusting screw 227 and acts to bias the valve body 225 in the direction of decrease of the opening degree of the throttling hole 231, i.e., the valve opening degree. Therefore, the valve body 225 is shifted into a position in which is attained a balance between the inner pressure of one pressure chamber 235 acting in the direction of increase of the opening degree of the throttling hole 231, the inner pressure of the other pressure chamber 236 acting in the direction of decrease of the opening degree of the throttling hole 231 and the biasing force of the spring 226.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle equipped with a supercooling degree control valve for controlling the degree of supercooling of high-pressure refrigerant (hereinafter referred to as subcooling).

[0002]

2. Description of the Related Art Conventionally, in an accumulator cycle, a subcool control valve (actually 55
No. 85671) is provided to obtain a subcool. As shown in FIG. 8, this sub-cool control valve operates in conjunction with the diaphragm 101 to restrict the throttle portion 102.
A valve element 103 for opening and closing the valve, an adjusting spring 104 for urging the valve element 103 in the direction of opening the throttle portion 102, a temperature sensitive tube 105 for converting a temperature change of the refrigerant downstream of the refrigerant condenser (not shown) into a pressure change, and the like. It is composed of The displacement of the valve element 103 is determined by the balance between the pressure in the temperature sensitive tube 105 acting on the upper side of the diaphragm 101 via the capillary tube 106, the high pressure acting on the lower side of the diaphragm 101, and the spring force of the adjusting spring 104. The opening degree of the throttle portion 102 is adjusted according to the displacement of the valve body 103.

[0003]

However, in the subcool control valve 100, the spring force of the adjusting spring 104 is set in advance so that a predetermined subcool (for example, 5 to 15 ° C.) can be obtained in the refrigerant condenser. (See Fig. 9). Therefore, for example, the subcool control valve 10 described above is used.
When 0 is used to form a subcool cycle as shown in FIG. 10 or FIG. 11 (both are not known cycles), the following problems occur.

The subcool cycle shown in FIG. 10 constitutes a heat pump cycle for automobile air conditioning, and the indoor condenser 2 arranged in the refrigerant compressor 200 and the duct 201.
02, the sub-cool control valve 100, the indoor evaporator 203 disposed on the windward side of the indoor condenser 202 in the duct 201, the evaporation pressure adjusting valve 204, the outdoor evaporator 205 disposed outside the duct 201, the accumulator 206, the room Evaporator 2
03 and the evaporative pressure adjusting valve 204 are bypassed 207,
And a solenoid valve 208 for opening and closing the detour 207.
In addition, the duct 201 is provided by the blower 209.
The air introduced into 01 is introduced into the passenger compartment, and the inside air introduction port 211 and the outside air introduction port 212 which are switched by the inside / outside air switching damper 210 are provided at the upstream end thereof.

Now, the detour 207 is closed (the solenoid valve 208
When the refrigerant flowing out of the subcool control valve 100 is guided to the indoor evaporator 203, the air introduced into the duct 201 by the blower 209 is cooled when passing through the indoor evaporator 203, and then the indoor condenser 203. When passing through 202, it is heated and blown into the vehicle interior. At this time, if the saturation temperature of the refrigerant flowing through the indoor condenser 202 is around 50 ° C., the cold air near 0 ° C. cooled by the indoor evaporator 203 will be blown to the indoor condenser 202.
Ideally, the indoor condenser 202 can obtain a subcool of about 50 ° C.

However, the bypass 207 is opened (the solenoid valve 208 is opened) to guide the refrigerant flowing out of the subcool control valve 100 to the outdoor evaporator 205, and the inside air mode (the inside / outside air switching damper 210 opens the outside air introduction port 212). (Close) is set and air inside the vehicle (inside air) at a temperature of about 30 ° C. is introduced into the duct 201, the air introduced into the duct 201 is not cooled by the indoor evaporator 203 and remains at the same temperature. The air is blown to the indoor condenser 202 at (30 ° C.). Therefore, the indoor condenser 202 can obtain only a subcool of about 20 ° C. at most.

The subcool cycle shown in FIG. 11 constitutes a refrigeration cycle for vehicle air conditioning. An outdoor condenser 213 is provided upstream of the indoor condenser 202, and an indoor evaporator 203 is provided in the duct 201. A bypass passage 214 through which the passing air can flow around the indoor condenser 202, and an air mix damper 215 for adjusting the ratio of the amount of air passing through the bypass passage 214 to the amount of air passing through the indoor condenser. Is provided.

Now, the air mix damper 215 fully opens the indoor condenser 202 (the position shown by the solid line in the figure), and the cold air near 0 ° C. cooled by the indoor evaporator 203 is cooled by the indoor condenser 202.
If the saturation temperature of the refrigerant flowing through the indoor condenser 202 is around 50 ° C., ideally, the indoor condenser 2
In 02, a subcool near 50 ° C is obtained. However,
In the case where the air mix damper 215 fully closes the indoor condenser 202 (the position indicated by the alternate long and short dash line in the figure) and the cool air near 0 ° C. cooled by the indoor evaporator 203 flows through the bypass passage 214, the indoor condenser 202. Since the cool air does not hit the inside, the indoor condenser 202 forms a mere refrigerant passage. Therefore, if the outside temperature (the temperature of the wind hitting the outdoor condenser 213) is 30
If the temperature is ° C, the outdoor condenser 213 and the indoor condenser 202
The saturation temperature (50 ℃) of the refrigerant flowing through the room is outside temperature (30 ℃)
Even if it is cooled down, only a subcool of 20 ° C can be obtained.

Therefore, in the subcool cycle shown in FIGS. 10 and 11, it is assumed that the indoor condenser 202 is at 20 ° C.
Subcool control valve 100 so that the subcool of
When the spring force of the adjusting spring 104 is set, the cold air near 0 ° C. cooled by the indoor evaporator 203 is cooled by the indoor condenser 20.
Even when hitting 2, I try to control the subcool to 20 ° C. Therefore, as described above, it becomes impossible to obtain a sufficiently large subcool (50 ° C. in the above description) by using the cold air near 0 ° C.

On the contrary, when the spring force of the adjusting spring 104 of the subcool control valve 100 is set so as to obtain a subcool of 50 ° C. in the indoor condenser 202, the air blown against the indoor condenser 202 in the cycle shown in FIG. Air temperature is 3
Even when the temperature is around 0 ° C. or when the air mix damper 215 closes the indoor condenser 202 in the cycle shown in FIG. 11, the indoor condenser 202 or the outdoor condenser 213 is operated at 50 ° C.
Since the sub-cool control valve 100 tries to reduce the opening degree of the throttle portion 102 until the sub-cool is obtained, the pressure on the high pressure side increases significantly.

Thus, the conventional subcool control valve 10
At 0, the spring force of the adjusting spring 104 is set so that a predetermined subcool is obtained in the indoor condenser 202, so that the temperature of the air hitting the indoor condenser 202 changes greatly as described above. It is not possible to deal with the case where the cycle is configured (it is not possible to control it by changing the subcool greatly). As a result, cycle efficiency is deteriorated and power consumption is increased.

The present invention has been made based on the above circumstances, and an object thereof is to obtain an optimum subcool for increasing cycle efficiency even when the temperature of air blown to an indoor condenser changes greatly. It is to provide a refrigeration cycle capable of

[0013]

In order to achieve the above object, the present invention comprises the following technical means. According to a first aspect of the present invention, a valve body is provided downstream of the refrigerant condenser for varying the passage cross-sectional area of the refrigerant passage, and the refrigerant flow rate is adjusted according to the valve opening degree of the valve body to obtain the refrigerant condenser. In the supercooling degree control valve for controlling the supercooling degree, the internal pressure changes according to the temperature change of the air sent to the refrigerant condenser. One pressure chamber that acts in a direction to increase the valve opening degree of the valve element by pressure, and the internal pressure changes according to the temperature change of the refrigerant flowing out of the refrigerant condenser, the higher the refrigerant temperature, the more It has the other pressure chamber that acts in a direction to reduce the valve opening degree of the valve body by pressure, and the valve based on the pressure difference between the internal pressure of the one pressure chamber and the internal pressure of the other pressure chamber. It is characterized by controlling the valve opening of the body.

The subcooling degree control valve according to claim 1 is
In Claim 2, it is arranged downstream of the above-mentioned refrigerant condenser in the flow direction of a refrigerant, and while incorporating the above-mentioned valve element,
A valve body provided with the one pressure chamber and the other pressure chamber, and is arranged on the windward side of the refrigerant condenser in a ventilation system that passes through the refrigerant condenser, of the air sent to the refrigerant condenser. A temperature-sensitive cylinder that detects a temperature change as a pressure change, and a transmission unit that communicates the temperature-sensitive cylinder with the one pressure chamber and transmits the pressure change of the temperature-sensitive cylinder to the one pressure chamber. It is characterized by

The subcooling degree control valve according to claim 1 is
The ventilation system according to claim 3, wherein a transmission member that transmits a temperature change of air to the one pressure chamber is provided on an outer wall surface that forms the one pressure chamber, and the transmission member passes through the refrigerant condenser. And is exposed to the flow of air sent to the refrigerant condenser.

The subcooling degree control valve according to any one of claims 1 to 3 corresponds to the pressure difference between the internal pressure of the one pressure chamber and the internal pressure of the other pressure chamber according to the fourth aspect. It is characterized in that the valve body has a diaphragm that is displaced according to the displacement of the diaphragm.

Further, in the present invention, a refrigerant condenser for condensing and liquefying the refrigerant flowing therein by heat exchange with the passing air, and a valve body for varying the passage cross-sectional area of the refrigerant passage downstream of the refrigerant condenser are provided. Having a supercooling degree control valve for controlling the degree of supercooling obtained in the refrigerant condenser by adjusting the refrigerant flow rate according to the valve opening degree of the valve body, and the subcooling degree control valve , The internal pressure changes according to the temperature change of the air sent to the refrigerant condenser, the higher the air temperature, the one pressure chamber that acts in the direction of increasing the valve opening degree of the valve body by the internal pressure, And the internal pressure changes according to the temperature change of the refrigerant flowing out from the refrigerant condenser, the higher the refrigerant temperature, the other pressure chamber that acts in the direction of reducing the valve opening degree of the valve body by the internal pressure. Having the internal pressure of the one pressure chamber and Serial based on the pressure difference between the inside pressure of the other pressure chamber and controls the valve opening degree of the valve body.

The subcooling control valve according to claim 5 is
In Claim 6, it is arranged downstream of the above-mentioned refrigerant condenser in the flow direction of a refrigerant, and while incorporating the above-mentioned valve element,
A valve body provided with the one pressure chamber and the other pressure chamber, and is arranged on the windward side of the refrigerant condenser in a ventilation system that passes through the refrigerant condenser, of the air sent to the refrigerant condenser. A temperature-sensitive cylinder that detects a temperature change as a pressure change, and a transmission unit that communicates the temperature-sensitive cylinder with the one pressure chamber and transmits the pressure change of the temperature-sensitive cylinder to the one pressure chamber. It is characterized by

The supercooling degree control valve according to claim 5 is
8. The ventilation system according to claim 7, wherein a transmission member that transmits a temperature change of air to the one pressure chamber is provided on an outer wall surface forming the one pressure chamber, and the transmission member passes through the refrigerant condenser. And is exposed to the flow of air sent to the refrigerant condenser.

The supercooling degree control valve according to any one of claims 5 to 7 is the subcooling degree control valve according to claim 8, which corresponds to the pressure difference between the internal pressure of the one pressure chamber and the internal pressure of the other pressure chamber. It is characterized in that the valve body has a diaphragm that is displaced according to the displacement of the diaphragm.

[0021]

The subcooling degree control valve for controlling the degree of subcooling obtained in the refrigerant condenser operates in such a manner that the internal pressure of one pressure chamber increases the valve opening of the valve body and the inside of the other pressure chamber. The pressure acts in the direction of reducing the valve opening of the valve body. The internal pressure of one pressure chamber changes according to the temperature change of the air sent to the refrigerant condenser, and the internal pressure of the other pressure chamber changes according to the temperature change of the refrigerant flowing out from the refrigerant condenser.

Therefore, when the temperature of the air blown to the refrigerant condenser (hereinafter referred to as suction air temperature) decreases, the internal pressure of one of the pressure chambers decreases first, so the valve body opens. It is displaced in the direction of decreasing degree. As a result, the temperature of the refrigerant flowing out from the refrigerant condenser (hereinafter referred to as the outlet refrigerant temperature) decreases, and the internal pressure of the other pressure chamber decreases, so that the valve body moves in the direction of increasing the valve opening. Displace.

When the intake air temperature of the refrigerant condenser rises, first, the internal pressure of one of the pressure chambers rises, so that the valve body is displaced in the direction of increasing the valve opening. As a result, the outlet refrigerant temperature of the refrigerant condenser rises and the internal pressure of the other pressure chamber rises, so that the valve body is displaced in the direction in which the valve opening degree decreases.

Thus, the outlet refrigerant temperature of the refrigerant condenser changes with the change of the intake air temperature of the refrigerant condenser.
Further, the degree of supercooling obtained in the refrigerant condenser is a temperature difference between the saturated refrigerant temperature in the refrigerant condenser and the outlet refrigerant temperature of the refrigerant condenser, so that the outlet refrigerant temperature of the refrigerant condenser is The change with the change of the intake air temperature means that the degree of supercooling obtained in the refrigerant condenser changes with the change of the intake air temperature of the refrigerant condenser.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of a vehicle air conditioner using the refrigeration cycle of the present invention will be described with reference to FIGS.
FIG. 1 is an overall schematic view of a vehicle air conditioner. The vehicle air conditioner 1 of this embodiment is mounted on an electric vehicle, and includes a duct 2 for introducing conditioned air into the vehicle compartment, a blower 3 for introducing air into the duct 2 and sending the air into the vehicle compartment, and an accumulator type. Refrigeration cycle 4 and air conditioner controller 5
(See FIG. 3).

The duct 2 is provided at its upstream end with inside air introduction ports 6 and 7 for introducing the vehicle interior air (inside air) and outside air introduction port 8 for introducing the vehicle outside air (outside air). The amount of introduced air into one of the inside air introduction port 6 and the outside air introduction port 8 is adjusted by the inside / outside air switching damper 9. The other inside air inlet 7 is always open.

The downstream end of the duct 2 is a defroster outlet 1 for discharging blown air toward the windshield of the vehicle.
0, a face outlet 11 for discharging blast air toward the upper half of the occupant, and a foot outlet 12 for discharging blast air toward the occupant's feet. Each outlet 10
12 is a mode damper 1 that operates according to the outlet mode.
3 and the outlet switching damper 14.

Further, inside the duct 2, a partition wall 15 is installed which divides the ventilation passage in the duct 2 into two. The partition wall 15 forms an air passage 2a extending from the inside air inlet 7 to the foot outlet 12, and an air passage 2b extending from the inside air inlet 6 or the outside air inlet 8 to the defroster outlet 10 and the face outlet 11.

The blower 3 comprises a centrifugal fan 3a and a blower motor 3b, and the amount of blown air (the rotation speed of the blower motor 3b) is determined according to the voltage (blower voltage) applied to the blower motor 3b. Blower voltage is the motor drive circuit 1
6 (see FIG. 3) via the control signal from the air conditioner controller 5.

The refrigeration cycle 4 includes a refrigerant compressor 17, an outdoor heat exchanger 18, a pressure reducing device 19, an indoor evaporator 20, an indoor condenser 21 (refrigerant condenser of the present invention), and a subcool control valve 2.
2 (supercooling degree control valve of the present invention), accumulator 23,
And a flow path switching means (described later).

The refrigerant compressor 17 includes an electric motor 24 (see FIG. 3).
The driving amount of the refrigerant is changed according to the rotation speed of the electric motor 24. Electric motor 24
Changes the rotation speed based on the frequency characteristic of the inverter 25. The outdoor heat exchanger 18 is arranged outside the duct 2 (outside the vehicle compartment) and exchanges heat between the outside air and the refrigerant.
By receiving the air blown from the outdoor fan 26, it functions as a refrigerant evaporator during heating operation and functions as a refrigerant condenser during cooling operation.

The decompressor 19 is used for cooling operation and dehumidification.
The refrigerant sent to the indoor evaporator 20 during defrosting is expanded under reduced pressure, and a capillary tube is used in this embodiment. The indoor evaporator 20 is arranged in the duct 2 and cools the air passing through the indoor evaporator 20 by heat exchange with a low-temperature low-pressure refrigerant that has been decompressed and expanded by the decompression device 19.

The indoor condenser 21 is arranged in the duct 2 below the indoor evaporator 20, and heats the air passing through the indoor condenser 21 by heat exchange with a high-temperature and high-pressure refrigerant. In addition, in the duct 2 in which the indoor condenser 21 is arranged, a cold air bypass passage 27 that allows the air passing through the indoor evaporator 20 to bypass the indoor condenser 21 is provided.
The cold air bypass passage 27 is provided with a cold air bypass damper 28 that opens and closes the cold air bypass passage 27 according to the operation mode.

As shown in FIG. 2, the subcool control valve 22 is a temperature sensor which detects a temperature change of the valve body 22a disposed downstream of the indoor condenser 21 and the air blown to the indoor condenser 21 as a pressure change. It is composed of a cylinder 22b and a capillary tube 22c (transmission means of the present invention) that connects the temperature-sensitive cylinder 22b and the valve body 22a.

The valve body 22a has a substantially cylindrical valve housing 220, a lower header 221 and an upper header 222 that hermetically cover an upper opening of the valve housing 220, and a partition plate 223 screwed to the inner peripheral surface of the lower header 221. A diaphragm 224 that is sandwiched between the lower header 221 and the upper header 222, a valve body 225 that operates in accordance with the displacement of the diaphragm 224, a spring 226 that urges the valve body 225, and an adjustment that adjusts the mounting load of the spring 226. It is composed of screws 227 and the like.

The valve housing 220 has an inlet joint 228 and an outlet joint 2 on its peripheral wall surface, which communicate with the internal space.
And 29 are provided. And the inlet joint 228
A throttle wall 230 for narrowing the passage cross-sectional area is provided in the internal space from the outlet joint 229 to the outlet joint 229, and the opening degree of the throttle hole 231 formed by the throttle wall 230 is adjusted by the displacement of the valve body 225. Further, the throttle wall 230 is provided with a bleed port 232 for preventing an abnormal rise on the high pressure side when the throttle hole 231 is fully closed by the valve body 225.

Lower header 221 and upper header 222
Forms a closed space that is airtightly separated from the internal space of the valve housing 220 by the partition plate 223. The lower header 221 is screwed to the upper end outer peripheral surface of the valve housing 220, and the upper header 222 is joined to the outer peripheral end surface of the lower header 221 by brazing or welding. Also,
The outer circumferences of the lower header 221 and the upper header 222 are entirely covered with a heat insulating material 233.

The partition plate 223 is made of a metal having excellent thermal conductivity (for example, made of copper, aluminum, etc.).
A large number of fins 234 are provided integrally (or separately) to improve heat transfer.

The diaphragm 224 is formed of a stainless steel thin plate, and one pressure chamber 235 formed between the upper header 222 and the closed space and the lower header 2 are formed.
21 and the partition plate 223 and the other pressure chamber 236. In this one pressure chamber 235,
Has a higher pressure than the refrigerant used in the refrigeration cycle 4,
A gas having a pressure / temperature characteristic gradient close to that of the refrigerant used is filled, and the other pressure chamber 236 is filled with a refrigerant used in the refrigeration cycle 4 or a gas having pressure / temperature characteristics close to that of the refrigerant. ing.

A stopper 237 is fixed to the lower surface of the diaphragm 224 (on the side of the other pressure chamber 236) to regulate the amount of displacement of the diaphragm 224 to the other side. When the internal pressure of the one pressure chamber 235 becomes larger than the internal pressure of the other pressure chamber 236 by a predetermined value or more, the stopper 237 contacts the inner wall surface of the lower header 221 and restricts the diaphragm 224 from further displacement. be able to. Note that the stopper 237 is provided with a communication passage 238 that communicates with the inside of the other pressure chamber 236 that is divided by the stopper 237 contacting the inner wall surface of the lower header 221.

The valve element 225 is arranged in the internal space of the valve housing 220 on the downstream side of the throttle hole 231 and has a stopper 237 and a rod 239 connected to the stopper 237.
The displacement of the diaphragm 224 is transmitted via the. The rod 239 is attached to the partition plate 223 with respect to the O-ring 2.
It is mounted so that it can be vertically moved (sliding) through 40.

The spring 226 is arranged between the valve body 225 and the adjusting screw 227, and biases the valve body 225 in a direction in which the opening degree of the throttle hole 231 (valve opening degree) becomes smaller. Therefore, the valve body 225 has the internal pressure of one pressure chamber 235 that acts in the direction of increasing the opening degree of the throttle hole 231 and the inside pressure of the other pressure chamber 236 that acts in the direction of decreasing the opening degree of the throttle hole 231. The pressure and the urging force of the spring 226 are displaced to a position balanced with each other.

The adjusting screw 227 is screwed to the inner peripheral surface of the valve housing 220 on the lower end side, and at the same time, the valve housing 22
It is rotatably assembled to the bottom cover 241 which is screwed to the lower end opening of 0 through the O-ring 242, and the mounting load of the spring 226 is adjusted by adjusting the screwing position with respect to the valve housing 220. It can be adjusted. The bottom cover 241 includes the bottom cover 2
A cap 243 is attached to cover the end of the adjusting screw 227 projecting from 41.

The temperature sensitive cylinder 22b is arranged in the duct 2 on the windward side of the indoor condenser 21. However, when the air passing through the indoor condenser 21 is separated into the inside air and the outside air by the partition wall 15 as in the present embodiment, it is arranged at a position where the air temperature on the refrigerant outlet side of the indoor condenser 21 can be detected. It
Inside the temperature-sensitive cylinder 22b, a temperature-sensitive gas for detecting a temperature change of air as a pressure change (for example, having a pressure higher than that of the refrigerant used in the refrigeration cycle 4 and having a pressure / temperature close to that of the refrigerant used). A medium having a characteristic gradient) is enclosed. Further, a large number of fins 244 are provided on the outer peripheral surface of the temperature sensitive cylinder 22b to improve heat transfer.

One end of the capillary tube 22c is connected to the temperature-sensitive cylinder 22b and the other end is connected to the central portion of the upper header 222 so that the inside of the temperature-sensitive cylinder 22b and one pressure chamber 235 communicate with each other. .

The accumulator 23 temporarily stores the refrigerant in the refrigeration cycle 4 and sends out only the gas-phase refrigerant in order to prevent the liquid refrigerant from being sucked into the refrigerant compressor 17.

The flow path switching means switches the flow direction of the refrigerant in accordance with the operation mode. The four-way valve 29, the first electromagnetic valve 30, the second electromagnetic valve 31, the third electromagnetic valve 32, and the check valve 33. , 34. The four-way valve 29 switches the refrigerant flow path according to the operation mode, and in the cooling mode,
The refrigerant discharged from the refrigerant compressor 17 is supplied with the outdoor heat exchanger 18
In the heating mode and the dehumidifying mode, the refrigerant discharged from the refrigerant compressor 17 is guided to the indoor condenser 21 side.

The first solenoid valve 30 is interposed in a first bypass 35 that bypasses the decompression device 19 and the indoor evaporator 20 and connects the outlet side of the outdoor heat exchanger 18 and the outlet side of the indoor evaporator 20. , And opens and closes the first detour 35. Second solenoid valve 31
Intervenes in the second detour circuit 36 that bypasses the decompression device 19 and connects the outlet side of the outdoor heat exchanger 18 and the inlet side of the indoor evaporator 20 to open and close the second detour circuit 36. The third solenoid valve 32 bypasses the subcool control valve 22 to bypass the indoor condenser 2
Third detour 3 connecting the outlet side of No. 1 and the upstream side of the check valve 33
7, the third detour 37 is opened and closed.

The flow of the refrigerant in each operation mode is indicated by an arrow in the figure. However, cooling mode: arrow C, heating mode: arrow H, dehumidification heating mode: arrow DH, dehumidification / defrost mode: arrow DC.

The air conditioner control device 5 has a built-in microcomputer (not shown) in which a control program for air conditioning control and various arithmetic expressions are stored. As shown in FIG. 3, the air conditioner control device 5 includes an air conditioner operation panel 3
Operation signal output from 8 and each sensor (described later)
Servo motors 9a for driving the dampers (inside / outside air switching damper 9, mode damper 13, outlet switching damper 14, cold air bypass damper 28) based on detection signals from
13a, 14a, 28a, motor drive circuit 16, inverter 25, outdoor fan 26, four-way valve 29, solenoid valve 30 to.
32 etc. are energized and controlled.

The above-mentioned sensors are the inside air sensor 39 for detecting the vehicle interior temperature Tr, the outside air sensor 40 for detecting the vehicle exterior temperature Tam, the solar radiation sensor 41 for detecting the solar radiation amount Ts, etc. (see FIG. 3).

Next, the operation in the heating mode and the dehumidifying heating mode in which the subcool control valve 22 functions will be described. A) In heating mode The refrigerant discharged from the refrigerant compressor 17 includes a four-way valve 29, an indoor condenser 21, a subcool control valve 22, a check valve 33, an outdoor heat exchanger 18, a first solenoid valve 30, and an accumulator 23.
After being sequentially flown through, the refrigerant is sucked into the refrigerant compressor 17 again. On the other hand, the air sent from the blower 3 passes through the indoor evaporator 20, is heated by the indoor condenser 21, and is blown out into the vehicle interior.

(B) In the dehumidifying and heating mode The refrigerant discharged from the refrigerant compressor 17 includes a four-way valve 29, an indoor condenser 21, a subcool control valve 22, a check valve 33, an outdoor heat exchanger 18, and a second solenoid valve 31. → Indoor evaporator 20 → Accumulator 23, and then the refrigerant compressor 17 again.
Is sucked into. On the other hand, the air sent from the blower 3 is dehumidified by the indoor evaporator 20, then heated by the indoor condenser 21 and blown out into the vehicle interior.

In the heating mode and the dehumidifying heating mode, the subcool control valve 22 adjusts the flow rate of the refrigerant passing through the throttle hole 231 in accordance with the valve opening degree of the valve body 225, so that the indoor condenser 21 operates. Control the resulting subcool. Therefore, the behavior of the valve body 225 will be described. The valve body 225 has an internal pressure of one pressure chamber 235 that acts to increase the opening of the throttle hole 231 and an internal pressure of the other pressure chamber 236 that acts to decrease the opening of the throttle hole 231. The spring 226 is displaced to a position balanced with the urging force of the spring 226.

The internal pressure of one pressure chamber 235 changes according to the temperature change of the air sent to the indoor condenser 21 in the duct 2, that is, the intake air of the indoor condenser 21, and the inside of the other pressure chamber 236. The pressure changes according to the temperature change of the outlet refrigerant flowing out from the indoor condenser 21. Therefore, the sub-cool control valve 22 has a difference between the internal pressure of the one pressure chamber 235 and the internal pressure of the other pressure chamber 236, that is, the indoor condenser 21.
The pressure P1 (the pressure of the medium sealed in the temperature sensing cylinder 22b and the one pressure chamber 235) which is approximately ΔP higher than the saturation pressure of the refrigerant corresponding to the intake air temperature of the refrigerant and the refrigerant corresponding to the outlet refrigerant temperature of the indoor condenser 21 ( Self-control is performed so that the difference from the saturation pressure P2 of the medium enclosed in the other pressure chamber 236) becomes substantially constant (see FIG. 4).

Now, considering the case where the temperature of the intake air of the indoor condenser 21 decreases, first, as the internal pressure of the temperature sensing cylinder 22b decreases, the internal pressure of one pressure chamber 235 also decreases. . Therefore, the valve body 225 is temporarily displaced in the direction in which the opening degree of the throttle hole 231 becomes smaller. As a result, the outlet refrigerant temperature of the indoor condenser 21 decreases, and the internal pressure of the other pressure chamber 236 to which the temperature change of the outlet refrigerant is transmitted via the partition plate 223 decreases. As a result, the valve body 225 is displaced in the direction in which the opening degree of the throttle hole 231 increases, and the internal pressure of the one pressure chamber 235, the internal pressure of the other pressure chamber 236, and the biasing force of the spring 226 are balanced. Stationary in position.

When the temperature of the intake air of the indoor condenser 21 rises, first, the internal pressure of the one pressure chamber 235 rises as the internal pressure of the temperature sensing cylinder 22b rises. Therefore, the valve body 225 is temporarily displaced in the direction in which the opening degree of the throttle hole 231 increases. As a result, the outlet refrigerant temperature of the indoor condenser 21 rises, so that the partition plate 223
The internal pressure of the other pressure chamber 236, to which the temperature change of the outlet refrigerant is transmitted via, increases. As a result, the valve body 225
Is displaced in a direction in which the opening degree of the throttle hole 231 becomes smaller,
The internal pressure of one pressure chamber 235 and the other pressure chamber 236
It stops at a position where the internal pressure of the spring and the biasing force of the spring 226 are balanced.

As described above, the outlet refrigerant temperature of the indoor condenser 21 changes with the change of the intake air temperature of the indoor condenser 21. Further, the subcool obtained in the indoor condenser 21 is the saturated refrigerant temperature in the indoor condenser 21 and the indoor condenser 21.
The temperature difference between the outlet refrigerant temperature of the indoor condenser 21 and the outlet refrigerant temperature of the indoor condenser 21 changes according to the change of the intake air temperature of the indoor condenser 21. It will change as the temperature of the intake air of the indoor condenser 21 changes.

FIG. 5 shows the optimum subcool for which the coefficient of performance (COP) of the refrigeration cycle 4 is maximum during the heating operation and the dehumidifying heating operation, with respect to the temperature change of the intake air of the indoor condenser 21. Because of such a relationship, it is possible to self-control the subcool obtained in the indoor condenser 21 to an optimum value at which the COP becomes substantially maximum by appropriately adjusting the mounting load of the spring 226 by the adjusting screw 227. Become.

Next, a second embodiment of the present invention will be described. FIG. 6 is a sectional view of the subcool control valve 22. As shown in FIG. 6, in the subcool control valve 22 of the present embodiment, a large number of fins 245 (transmission member of the present invention) are integrally or separately provided on the outer wall surface of the upper header 222 forming one pressure chamber 235. It is a thing.

As shown in FIG. 7, the subcool control valve 22 has a valve main body 22a installed outside the duct 2.
Only the fins 245 are arranged in the duct 2 so as to be exposed to the flow of the intake air of the indoor condenser 21. As a result, the temperature change of the intake air of the indoor condenser 21 can be detected by the fins 245 and transmitted to the one pressure chamber 235. Therefore, the temperature sensing cylinder 22b and the capillary tube 22c shown in the first embodiment are eliminated. can do. Although the valve main body 22a is installed outside the duct 2 in FIG. 7, it may be installed inside the duct 2.

[Modification] In the first embodiment, the indoor condenser 2 is used.
Although the fins 244 are provided on the outer peripheral surface of the temperature sensing cylinder 22b in order to improve the responsiveness of detecting the intake air temperature of No. 1, the fins 244 do not necessarily have to be provided. Similarly, although the partition plate 223 is provided with a large number of fins 234, it is not always necessary to provide the fins 234.

Further, the bleed port 23 is attached to the diaphragm wall 230.
However, the bleed port 232 may be omitted. Furthermore, the lower header 221 and the upper header 2
Although the outer periphery of 22 is covered with the heat insulating material 233, it is not always necessary to cover with the heat insulating material 233.

In the embodiment, one pressure chamber 235 is filled with a gas having a pressure higher than that of the refrigerant used in the refrigerating cycle 4 and having a pressure / temperature characteristic gradient close to that of the refrigerant used, and the other. The pressure chamber 236 is filled with a refrigerant used in the refrigeration cycle 4 or a gas having a pressure / temperature characteristic close to that of the refrigerant.
A refrigerant used in the refrigeration cycle 4 or a gas having a pressure / temperature characteristic close to that of the refrigerant is enclosed, and the other pressure chamber 236 has a lower pressure / temperature characteristic gradient than the refrigerant used in the refrigeration cycle 4. Gas may be enclosed.

[0065]

According to the refrigeration cycle of the present invention, in the supercooling degree control valve, the internal pressure of one pressure chamber that changes according to the temperature change of the intake air of the indoor condenser and the temperature of the outlet refrigerant of the indoor condenser. By controlling the valve opening based on the pressure difference from the internal pressure of the other pressure chamber, which changes according to the change,
The degree of supercooling obtained in the indoor condenser changes with changes in the intake air temperature of the indoor condenser. Therefore, even if the intake air temperature of the indoor condenser changes significantly, the cycle efficiency (CO
It is possible to obtain the optimum degree of supercooling in which P) is substantially maximum.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a subcool control valve.

FIG. 3 is a block diagram showing a control system of this embodiment.

FIG. 4 is a graph showing a valve opening characteristic of a subcool control valve.

FIG. 5 is a graph showing a relationship between an intake air temperature of an indoor condenser and an optimum subcool value.

FIG. 6 is a sectional view of a subcool control valve according to a second embodiment of the present invention.

7 is a schematic diagram of an air conditioner using the subcool control valve shown in FIG.

FIG. 8 is a schematic diagram of a subcool control valve according to a conventional technique.

FIG. 9 is a graph showing the relationship between the intake air temperature of the indoor condenser and the subcool value.

FIG. 10 is an overall schematic diagram of an air conditioner for explaining a conventional technique.

FIG. 11 is an overall schematic diagram of an air conditioner for explaining a conventional technique.

[Explanation of symbols]

 2 duct 4 refrigeration cycle 21 indoor condenser 22 subcool control valve (supercooling degree control valve) 22a valve body 22b temperature sensing tube 22c capillary tube (transmission means) 224 diaphragm 225 valve body 235 one pressure chamber 236 the other pressure chamber 245 Fin (Transmission member)

Claims (8)

[Claims] 1. A refrigerant condenser is provided downstream of a refrigerant condenser, the valve body having a variable passage cross-sectional area of the refrigerant passage, and the refrigerant flow rate is adjusted according to the valve opening degree of the valve body to obtain the refrigerant condenser. In the subcooling degree control valve for controlling the subcooling degree, the subcooling degree control valve changes the internal pressure according to the temperature change of the air sent to the refrigerant condenser, and the higher the air temperature, the more One pressure chamber that acts in a direction to increase the valve opening degree of the valve element by pressure, and the internal pressure changes according to the temperature change of the refrigerant flowing out of the refrigerant condenser, the higher the refrigerant temperature, the more It has the other pressure chamber that acts in a direction to reduce the valve opening degree of the valve body by pressure, and the valve based on the pressure difference between the internal pressure of the one pressure chamber and the internal pressure of the other pressure chamber. Degree of supercooling characterized by controlling the valve opening of the body Valve. 2. A valve main body, which is arranged downstream of the refrigerant condenser in the flow direction of the refrigerant, has the valve body therein, and is provided with the one pressure chamber and the other pressure chamber, and the refrigerant. A temperature sensitive tube which is arranged on the windward side of the refrigerant condenser in a ventilation system that passes through the condenser and detects a temperature change of the air sent to the refrigerant condenser as a pressure change; 2. The supercooling degree control valve according to claim 1, further comprising a transmission unit that communicates with a pressure chamber and transmits a pressure change of the temperature sensing cylinder to the one pressure chamber. 3. A ventilation system, wherein a transmission member for transmitting a temperature change of air to the one pressure chamber is provided on an outer wall surface forming the one pressure chamber, and the transmission member passes through the refrigerant condenser. The supercooling degree control valve according to claim 1, wherein the supercooling degree control valve is arranged so as to be exposed to a flow of air sent to the refrigerant condenser. 4. A diaphragm that is displaced according to a pressure difference between the internal pressure of the one pressure chamber and the internal pressure of the other pressure chamber, wherein the valve body is a valve that interlocks with the displacement of the diaphragm. 4. The supercooling degree control valve according to claim 1, wherein the opening degree is variable. 5. A refrigerant condenser for condensing and liquefying a refrigerant flowing inside by heat exchange with passing air, and a valve body for varying a passage cross-sectional area of a refrigerant passage downstream of the refrigerant condenser. A subcooling degree control valve that controls the degree of subcooling obtained in the refrigerant condenser by adjusting the refrigerant flow rate according to the valve opening degree of the body, and the subcooling degree control valve is provided in the refrigerant condenser. The internal pressure changes in accordance with the temperature change of the air sent to the one of the pressure chambers, and the higher the air temperature, the more the internal pressure acts to increase the valve opening of the valve body, and the refrigerant condenser. The internal pressure changes according to the temperature change of the more outflowing refrigerant, the higher the refrigerant temperature, the other pressure chamber that acts in the direction of decreasing the valve opening degree of the valve body by the internal pressure, the one Internal pressure of the pressure chamber of Refrigeration cycle and controls the valve opening degree of the valve body based on pressure difference between the section pressure. 6. The supercooling degree control valve is disposed downstream of the refrigerant condenser in the direction of flow of the refrigerant, contains the valve body, and is provided with the one pressure chamber and the other pressure chamber. A valve body, and a temperature sensitive tube that is arranged on the windward side of the refrigerant condenser in a ventilation system that passes through the refrigerant condenser, and detects a temperature change of air sent to the refrigerant condenser as a pressure change; The refrigeration cycle according to claim 5, further comprising: a transmission unit that communicates the temperature-sensitive cylinder with the one pressure chamber and transmits a pressure change of the temperature-sensitive cylinder to the one pressure chamber. 7. The subcooling degree control valve is provided with a transmission member for transmitting a temperature change of air to the one pressure chamber on an outer wall surface forming the one pressure chamber,
The refrigeration cycle according to claim 5, wherein the transmission member is disposed in a state where it is exposed to a flow of air sent to the refrigerant condenser in a ventilation system that passes through the refrigerant condenser. 8. The subcooling degree control valve has a diaphragm that is displaced according to a pressure difference between an internal pressure of the one pressure chamber and an internal pressure of the other pressure chamber, and the valve body is The refrigeration cycle according to any one of claims 5 to 7, wherein the valve opening degree is changed in association with the displacement of the diaphragm.