JP2001121949A - Refrigerating cycle apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a shortage in quantity of a circulating refrigerant due to individual operation of an evaporator on the front seat side in a refrigerating cycle apparatus having the front seat side evaporator 15 and a rear seat side evaporator 28 connected in parallel and having no solenoid valve for the rear seat side evaporator 28. SOLUTION: A refrigerant outlet of a sub-evaporator 28 is provided on the lower side. By this arrangement, in two-split front and rear evaporators, two passage are largely demarcated, and a refrigerant of the approximately half passage on the outlet side flows out of a lower outlet so that it will not stay in the evaporator. Accordingly, even if the operation of the rear seat side air conditioning unit 25 is stopped, the interior of the sub-evaporator 28 is not full of the refrigerant, so that the quantity of a circulating refrigerant in a refrigerating cycle R is not decreased to prevent a problem of lowering in cooling capacity due to the shortage of a refrigerant in a front seat side air conditioning circuit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle apparatus having a main and a sub-evaporator provided in parallel, for example, a front seat air conditioning unit for air conditioning a front seat side area of a vehicle, and a vehicle interior. The present invention is suitably applied to a vehicle air conditioner including a rear seat air conditioning unit for air conditioning a rear seat area.

[0002]

2. Description of the Related Art In recent years, the demand for large passenger vehicles such as minivans in the market has increased, and since the capacity of the large passenger vehicle is large, the air conditioner for the vehicle is also required to have a large capacity. The air conditioning unit has also changed from a single air conditioner in which an air conditioning unit is disposed only on the front seat side of the vehicle compartment to a dual air conditioner in which air conditioning units are disposed on both the front seat side and the rear seat side in the vehicle compartment. In the refrigeration cycle of this dual air conditioner, an evaporator is provided independently on the front seat side and the rear seat side, and a compressor and a condenser are commonly used.

[0003] In recent years, in order to reduce the cost of the air conditioner, in recent years, an increasing number of vehicles have eliminated the solenoid valve for interrupting the flow of refrigerant to the rear evaporator. In the case of the dual air conditioner, when there is no occupant in the rear seat side of the vehicle interior, the operation of the rear seat air conditioning unit is stopped, and the front seat alone operation state is performed in which only the front seat air conditioning unit is operated. At the time of the sole operation on the front seat side, the following situation occurs in the refrigeration cycle.

That is, in the rear air conditioning unit, the air supply to the rear air evaporator is stopped, so that the liquid refrigerant accumulated in the rear air evaporator evaporates little by little. The temperature of the temperature sensing portion of the temperature-type expansion valve, which forms the pressure reducing means, rises toward the temperature of the surrounding atmosphere (room temperature) due to the decrease in the amount of the refrigerant passing therethrough. The degree of superheat increases, so that the valve element of the temperature-type expansion valve opens only by a minute opening. Then, the low-pressure refrigerant that has passed through the thermal expansion valve flows into the rear seat evaporator.

[0005]

As described above, when the front seat side is operated alone, the temperature expansion valve on the rear seat side repeatedly opens and closes minutely, and the refrigerant flows into the rear seat side evaporator. Accumulate. Conventionally, the refrigerant inlet / outlet of the evaporator is provided on the upper side, and the amount of the refrigerant circulating in the refrigeration cycle is reduced by filling the rear seat evaporator with the inflowing refrigerant,
There is a problem that the operating front seat side air conditioning unit runs short of refrigerant and the cooling capacity is reduced.

On the other hand, in the prior art, there is a means of increasing the capacity of a liquid receiver for adjusting the amount of refrigerant in a refrigeration cycle to increase the amount of enclosed refrigerant. In addition, it becomes difficult, and it is contrary to the recent trend of refrigerant saving.

Japanese Unexamined Patent Publication No. 9-109656 discloses that in a dual air conditioner type vehicle air conditioner, a solenoid valve for interrupting the flow of refrigerant to a rear seat evaporator for a certain period of time when a front seat is operated alone. It describes that the refrigerant accumulated in the rear seat evaporator is pushed out by forcibly opening it for a short time at intervals. However, a vehicle in which the solenoid valve on the rear seat side is eliminated in order to reduce the cost of the air conditioner cannot cope with the shortage of the circulating refrigerant.

In view of the above, the present invention provides a refrigeration cycle apparatus in which a main evaporator and a sub-evaporator, which are mainly used, are connected in parallel, and which does not have a solenoid valve for the sub-evaporator. It is an object of the present invention to provide a system capable of resolving a shortage of a circulating refrigerant amount due to an isolated operation on a main evaporator side without increasing the amount.

[0009]

In order to achieve the above object, the inventions according to the first and second aspects are characterized in that the refrigerant outlet of the sub-evaporator is located at the lower side.

[0010] With this structure, the refrigerant in the outlet flow path does not flow out from the lower outlet to the outside and does not accumulate in the evaporator. Thus, even if the operation of the sub air conditioning unit is stopped, the inside of the sub evaporator is not filled with the refrigerant, and the amount of the circulating refrigerant in the refrigeration cycle is not reduced. Thus, it is possible to prevent a decrease in cooling capacity due to insufficient refrigerant.

In particular, when the front and rear two-part type evaporator according to the second aspect is used, the evaporator is largely divided into two flow paths. Is discharged from the lower outlet to the outside and does not accumulate in the evaporator, so that the effect is large.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an overall layout of an embodiment in which the present invention is applied to a minivan type passenger car.
The cabin 11 of the minivan type vehicle 10 has second and third seats (rear seats) behind the front seats (driver and passenger seats).
, And forms a long space in the vehicle front-rear direction.

The front seat air-conditioning unit 12 is disposed inside a frontmost instrument panel (not shown) in the passenger compartment 11 and air-conditions a region on the front seat side in the passenger compartment. The front seat side air conditioning unit 12 has a case 13 that forms an air passage,
An air blower 14 is arranged upstream of the case 13.
The blower 14 blows inside air or outside air that is switched and introduced from an inside / outside air switching box (not shown).

Downstream of the blower 14, an evaporator (main evaporator) 15 of the refrigeration cycle R is arranged as a cooling heat exchanger for cooling the blown air. In this example, the evaporator is 2
It is a split type evaporator of split / left and right split type. Here, the refrigeration cycle R has a well-known configuration, and includes a compressor 16 driven by a vehicle engine (not shown) via an electromagnetic clutch 16a. The refrigerant is compressed to a high temperature and a high pressure by the compressor 16, and the gas refrigerant discharged from the compressor 16 is introduced into a condenser 17, where the gas refrigerant is separated from the outside air blown by a cooling fan (not shown). Exchanges heat and condenses.

The refrigerant that has passed through the condenser 17 is separated into a liquid-phase refrigerant and a gas-phase refrigerant by a receiver 18, and the liquid-phase refrigerant is stored in the receiver 18. The liquid refrigerant from the receiver 18 is decompressed into a low-pressure gas-liquid two-phase refrigerant by a temperature type expansion valve (decompression means) 19, and the depressurized low-pressure refrigerant is rapidly heated from the conditioned air in the evaporator 15 and evaporated. It is made to let.

As is well known, the temperature type expansion valve 19 is connected to the evaporator 1.
The valve opening is automatically adjusted so that the superheat degree of the refrigerant at the outlet 5 is maintained at a predetermined value. Therefore, the temperature type expansion valve 1
9 is a temperature sensing part that senses the refrigerant temperature at the outlet of the evaporator 15;
The first pressure chamber to which the pressure corresponding to the refrigerant temperature sensed by the temperature sensing part is applied, the second pressure chamber to which the refrigerant pressure (cycle low pressure) of the evaporator 15 is applied, and the first and second pressure chambers A diaphragm is provided, and the diaphragm and the valve body are displaced according to the pressure difference between the first and second pressure chambers and the spring force to adjust the flow rate of the refrigerant.

The gas refrigerant evaporated in the evaporator 15 is again sucked into the compressor 16 and compressed. In the refrigeration cycle R, devices such as the compressor 16, the condenser 17, and the liquid receiver 18 are mounted in the engine room 20 on the front side of the passenger compartment 11.

In the front seat side air conditioning unit 12, a temperature sensor 21 is disposed at an air blowing portion of the evaporator 15, and a temperature of the evaporator air blown out (evaporator cooling temperature) detected by the temperature sensor 21 is a predetermined value. When the pressure drops below, the power supply to the electromagnetic clutch 16a is cut off to stop the operation of the compressor 16, thereby preventing the frost of the evaporator 15.

Next, on the downstream side of the air flow of the evaporator 15,
A heater core (heating heat exchanger) 22 for heating the conditioned air with hot water from the vehicle engine is provided. A bypass path 23 is formed on the side of the heater core 22. A plate-shaped air mix door 24 is rotatably disposed adjacent to the heater core 22. By selecting a rotation position of the air mix door 24, the hot air passing through the heater core 22 and being heated can be bypassed. The temperature of the blown air is adjusted by adjusting the ratio of the amount of the cool air to the passing air.

At the downstream end of the front air conditioning unit 12, a defroster outlet, a face outlet, and a foot outlet (not shown) are opened. The conditioned air passing through the openings is blown out toward the inner surface of the vehicle window glass, the head of the occupant on the front seat side, and the feet.

Next, the rear seat air-conditioning unit 25 is disposed at the rear of the passenger compartment 11, for example, at a side portion of the rear seat so as to air-condition the rear seat side of the passenger compartment. A blower 27 that sucks in air and blows air is provided in a case 26 of the rear seat air conditioning unit 25, and a rear seat evaporator (sub-evaporator) 28 is disposed downstream of the blower 27. . In this example, the evaporator is a stacked evaporator of a two-part split type.

Next, on the downstream side of the air flow of the evaporator 28,
A heater core (heating heat exchanger) 29 for heating the conditioned air with hot water from the vehicle engine is provided. A bypass path 30 is formed on the side of the heater core 29. A plate-shaped cold air bypass door 31 is rotatably disposed adjacent to the heater core 29, and the cold air bypass door 31 allows the bypass passage 30 to be connected to the rear seat air conditioning unit 2.
Opening and closing according to the blowing mode 5 and the air volume level.

At the refrigerant inlet of the rear seat evaporator 28, a rear seat temperature type expansion valve 32 is provided. This rear seat side temperature type expansion valve 32 is the same as the front seat side temperature type expansion valve 19, and decompresses the high temperature and high pressure liquid refrigerant from the receiver 18 into a low temperature and low pressure gas-liquid two-phase refrigerant. This means adjusts the valve opening so that the degree of superheat of the refrigerant at the outlet of the rear seat evaporator 28 becomes a predetermined value, and adjusts the refrigerant flow rate.

In the refrigeration cycle R, the inlet side of the rear seat side temperature type expansion valve 32 is connected via a high pressure pipe 33 to the inlet side of the front seat side temperature type expansion valve 19. The outlet side of the evaporator 28 is connected to the outlet side of the evaporator 15 on the front seat side via a low-pressure pipe 34. Thus, the rear evaporator 28 and the thermal expansion valve 32 are connected in parallel with the front evaporator 15 and the thermal expansion valve 19.

In the rear-seat air conditioning unit 25, a face blowing opening 36 and a blowing mode door 37 are disposed immediately downstream of the evaporator 28, and the cool air cooled by the rear-seat evaporator 28 is blown through the face. The air is blown from the opening 36 through the rear face duct 38 to the head of the rear occupant from the ceiling outlet 38a.

The warm air heated by the heater core 29 is blown out from the rear seat foot outlet 39a through the rear seat foot duct 39 toward the feet of the rear occupant.

FIG. 2A shows both the front and rear air conditioning units 1.
The state of the gaseous phase and the liquid phase of the refrigerant in the refrigeration cycle R when the two and 25 are simultaneously operated as described above is shown. The front and rear temperature expansion valves 19 and 32 are respectively connected to the front and rear evaporators 15 and
The valve opening degree is adjusted to correspond to the heat load of 28, and the refrigerant flows at a flow rate corresponding to the heat load.
5 and 28 are kept at an appropriate amount of refrigerant, and there is no decrease in cooling capacity due to an insufficient amount of circulating refrigerant.

By the way, when an occupant is on only the front seat side and no occupant is on the rear seat side, a switch on the front seat operation panel or the rear seat operation panel (neither is shown). The rear blower 27 is stopped by the operation. Thereby, the conditioned air is not blown to the rear seat air conditioning unit 25, and the air conditioning operation of the rear seat air conditioning unit 25 is stopped, so that only the front seat air conditioning unit 12 is in the single operation state.

According to experiments conducted by the present inventors, in a dual air conditioner type vehicle air conditioner having no solenoid valve for a rear seat evaporator, when the front seat side is operated alone, a problem to be solved by the invention is as follows. As described above, in the rear-seat air conditioning unit 25, the rear-seat-side thermal expansion valve 32 repeatedly opens and closes minutely, and the refrigerant flows into and accumulates in the rear-seat evaporator 28, As the liquid gradually fills, the amount of refrigerant circulating in the refrigeration cycle R decreases, and the front seat evaporator 15 of the operating front seat air conditioning unit 12 runs short of refrigerant and the cooling capacity decreases. It turned out to be. FIG.
(B) shows the state of the gas phase and the liquid phase of the refrigerant in the refrigeration cycle R during the front-seat independent operation.

Therefore, in the present embodiment, the refrigerant outlet of the rear seat evaporator is set to the lower side in order to eliminate a decrease in the cooling capacity due to an insufficient amount of the circulating refrigerant. In addition, the lower side means the ground side with respect to the top and bottom, and means the side where the refrigerant falls due to the relationship with gravity.

FIG. 3 shows the structure of the sub-evaporator 28 according to the embodiment of the present invention, that is, the stacked evaporator of the front-back split type. FIG. 4 shows the structure of a sub-evaporator of the same type as the conventional embodiment. In the structure of the conventional evaporator, the liquid refrigerant flowing from the inlet a accumulates in the inlet tube d, and when this portion becomes full, it passes through the side passage f to the outlet tube h.
When this portion also becomes full, it exits from the outlet j and returns to the compressor 16. However, in the structure of the evaporator of the present invention, the liquid refrigerant flowing from the inlet a accumulates in the inlet tube d, and when this portion becomes full, flows into the outlet tube h through the side passage f. Since h communicates with the outlet j on the lower side, the flowing liquid refrigerant exits from the outlet j and returns to the compressor 16 without being accumulated.

As described above, by adopting this structure (the refrigerant outlet j is located on the lower side (ground side) with respect to the top and bottom), the laminated evaporator 28 of the front and rear two-partition type is largely divided into two flow paths. The refrigerant in about half the flow path at the rear (outlet) flows out from the lower outlet j and does not accumulate in the evaporator.

Therefore, even if the operation of the rear air conditioning unit 25 is stopped, the inside of the sub-evaporator 28 is not filled with the refrigerant,
The amount of circulating refrigerant in the refrigeration cycle R is not reduced, and a decrease in cooling capacity due to a shortage of refrigerant in the front seat air conditioning unit 12 during operation can be prevented.

The structure of the present invention can also be applied to other types of laminated evaporators. For example, in the case of a two-part front and two-part left and right evaporator, the evaporator is largely divided into four flow paths, and about four minutes on the outlet side. The refrigerant in the first flow channel flows out from the lower outlet j and does not accumulate in the evaporator. As a result, although the amount of refrigerant accumulated becomes larger than that of the evaporator divided into two parts before and after, the cooling capacity can be prevented from lowering due to an insufficient amount of circulating refrigerant.

[Brief description of the drawings]

FIG. 1 is an overall system configuration diagram of a vehicle air conditioner showing an embodiment of the present invention.

2A is a diagram illustrating a conventional embodiment in which front and rear air conditioning units are simultaneously operated, FIG. 2B is a diagram illustrating a conventional embodiment in which only a front air conditioning unit is independently operated, and FIG. 2C is an embodiment of the present invention; FIG. 4 is a schematic diagram showing a state of a gas phase and a liquid phase of the refrigerant in each refrigeration cycle R when only the front air conditioning unit is operated alone.

FIG. 3 shows a sub-evaporator according to an embodiment of the present invention,
(A) is a perspective view showing a structure, (b) is a schematic diagram showing a flow of a refrigerant.

FIG. 4 shows a sub-evaporator of the same type as the conventional embodiment,
(A) is a perspective view showing a structure, (b) is a schematic diagram showing a flow of a refrigerant.

[Explanation of symbols]

 14 Front Seat Fan 15 Front Seat Evaporator (Main Evaporator) 16 Compressor 17 Condenser 18 Liquid Receptor 19 Front Seat Expansion Valve 27 Rear Seat Blower 28 Rear Seat Evaporator (Sub-Evaporator) 32 Rear Seat side expansion valve

Claims (2)

[Claims] 1. A compressor for compressing and discharging a refrigerant.
A condenser (17) for cooling and condensing the gas refrigerant discharged from the compressor (16); and a first decompression means (1) for decompressing and expanding the liquid refrigerant condensed in the condenser (17).
9), a main evaporator (15) for evaporating the refrigerant decompressed and expanded by the first decompression means (19), a first blower (14) for blowing the main evaporator (15), First
Provided in parallel with the pressure reducing means (19) of the condenser (1).
A second pressure reducing means (32) for decompressing and expanding the liquid refrigerant condensed in 7), and provided in parallel with the main evaporator (15);
A refrigeration cycle apparatus including a sub-evaporator (28) for evaporating the refrigerant decompressed and expanded by the second decompression means (32), and a second blower (27) for blowing the sub-evaporator (28). In the above, at least the second decompression means (32) for decompressing and expanding the refrigerant flowing into the sub-evaporator (28) is a temperature-type expansion valve that adjusts the superheat degree of the outlet refrigerant of the sub-evaporator (28). A refrigeration cycle apparatus comprising: at least the sub-evaporator (28) is a stacked evaporator; and a refrigerant outlet of the sub-evaporator (28) is on a lower side. 2. The refrigeration cycle apparatus according to claim 1, wherein said sub-evaporator (28) is constituted by a stacked evaporator of a front-back split type.