JPH05203290A - Car air conditioner - Google Patents

Abstract

PURPOSE:To maintain the control of refrigerant supply without troubles and prevent the generation of a cooling failure in a car even when an expansion valve is installed outside a rear cooler due to its layout restrictions by protecting the expansion valve from excessive cooling. CONSTITUTION:Small-sized pipes 19 and 21 and a series of flow passages in a cover 17 constitute an auxiliary air passage 26 where an expansion valve 15 is housed in the cover 17. The temperature of air forcedly introduced from an opening 25 on the small-sized pipe 21 by a differential pressure built up between an opening 13 and the opening 25 is similar to the temperature of a heat sensing bulb 33. Furthermore, the temperature of the air is higher than that of the heat sensing bulb 33 since sufficient heat is provided by the case 1, a fan 5 or the small-sized pipe 21. The air exchanges the heat with the expansion valve 15 in the cover 17 and it is discharged from the opening 13 into a front side case 1a by way of the small-sized pipe 19. This construction makes it possible to inhibit the temperature of the expansion valve 15 from being lower than that of the heat sensing bulb 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air conditioner.

[0002]

2. Description of the Related Art In a refrigeration cycle used in an air conditioner for an automobile, an expansion valve is provided with a device for adjusting a supply amount of a refrigerant to an evaporator according to a temperature in a vehicle compartment. As this refrigerant supply amount adjusting device, for example, a device using a temperature sensitive tube is known as a general one. The temperature sensitive tube is attached to the pipe at the outlet of the evaporator, senses the refrigerant temperature at that position, and adjusts the expansion valve of the expansion valve to an opening degree corresponding to the refrigerant temperature.

The function of the expansion valve is to eject the refrigerant in a mist state from the throttle valve, thereby changing the refrigerant into a low-temperature low-pressure refrigerant mist, which enables uniform and efficient evaporation in the evaporator. Therefore, the expansion valve also partially absorbs heat. Due to this endothermic action, when the expansion valve becomes lower than the temperature of the heat-sensitive cylinder portion, the refrigerant supply amount adjusting device set on the assumption that the expansion valve has a higher temperature is normally operated to adjust the refrigerant supply amount. Can not be done. Therefore, the supply amount of the refrigerant is extremely reduced, and overheated steam is generated in the evaporator, so that the vehicle interior may not be sufficiently cooled.

Therefore, conventionally, in order to prevent excessive cooling of the expansion valve described above, the expansion valve is arranged in front of the intake port for sucking the air in the vehicle interior to the evaporator, and the expansion valve is always kept in the air in the vehicle interior. Was warming up at.

[0005]

However, if there is a layout restriction in arranging the air conditioner in the vehicle compartment, the expansion valve cannot always be arranged in front of the air intake port in the vehicle compartment. An example is a rear cooler in an air conditioner called a so-called dual air conditioner type.

This dual air conditioner type is equipped with an expansion valve, an evaporator and a fan (blower) in a dash panel and a trunk room, respectively, and uses a refrigerant supplied through a compressor and a condenser in an engine room to drive a vehicle. It is an air conditioner that blows cold air into the room from the front and back.

[0007] Of these, provided on the trunk room side,
Due to layout restrictions, the so-called rear cooler had to have the expansion valve outside the rear cooler, and could not be placed in front of the air inlet. Therefore, there is a problem that it is difficult to prevent excessive expansion valve cooling.

Further, a relatively high temperature liquid refrigerant that has passed through the condenser is supplied to the rear cooler from the engine room side, but since the distance between the engine room and the trunk room is long, the refrigerant flows while flowing through the pipe between them. The refrigerant is further cooled. Therefore, the refrigerant having a temperature lower than that of the refrigerant supplied to the dash panel side is supplied to the rear cooler. Therefore, it becomes more difficult to prevent the excessive cooling of the expansion valve, and for example, the temperature of the expansion valve becomes 10 to 15 degrees lower than the temperature of the refrigerant after passing through the evaporator that is sensed by the temperature sensing cylinder, and the expansion valve is cooled by the refrigerant. However, there is a problem in that the cooling amount inside the vehicle cannot be controlled, and poor cooling occurs in the passenger compartment.

[0009]

In order to solve the above problems, an automobile air conditioner of the present invention has an expansion valve for a refrigeration cycle disposed outside an air passage, and the inside of the air passage is provided with an expansion valve for the refrigeration cycle. The evaporator and the fan of the refrigeration cycle are sequentially arranged from the inlet side to the outlet side, and when the fan is driven, the vehicle interior air sucked from the inlet of the air passage is cooled by the evaporator. In the air conditioner for a vehicle that discharges from the outlet into the vehicle compartment, each has an opening in an air passage portion between the evaporator and the fan and an air passage portion between the fan and the outlet, and By providing the sub air passage in which the expansion valve is arranged, the flow of air is generated in the sub air passage due to the pressure difference between the two openings, and the air is distributed in the sub air passage. It has been and makes it possible to prevent excessive cooling of the expansion valve.

[0010]

The pressure difference is generated in the air passage by driving the fan. In addition, secondary pressure such as dynamic pressure is also generated by the flow of air in the air passage caused by this pressure difference. Therefore, between the air passage portion between the evaporator and the fan and the air passage portion between the fan and the outlet,
There is some pressure difference.

Therefore, the forced flow of air occurs in the sub air passage due to the pressure difference between the openings, so that the expansion valve existing in the sub air passage is always exposed to the air flow. Become. This air is never colder than the refrigerant exiting the evaporator. Therefore, due to the heat exchange with the air, the expansion valve does not become lower than the evaporator outlet portion, so that the expansion valve is prevented from being excessively cooled. For this reason, the expansion valve can always control the supply amount of the refrigerant normally, and the poor cooling of the vehicle interior does not occur.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1 showing a rear cooler. [First Embodiment] The case 1 is composed of a front case 1a and a rear case 1b, and the inside of the case 1 constitutes an air passage 2. An evaporator 3 is housed in the front case 1a, and a fan 5 is housed in the rear case 1b. The fan 5 is driven by a motor 7 attached to the rear case 1b. An air inlet 9 is provided on the front surface of the front case 1a.
However, an air outlet 10 is provided on the rear surface of the rear case 1b, and the front case 1a and the rear case 1b communicate with each other through a communication hole 11. An opening 13 is provided in the front case 1 a between the evaporator 3 and the fan 5.
On the other hand, outside the case 1, a closed cover 17 that accommodates the expansion valve 15 is arranged. The cover 17 has two ports 17a and 17b. One port 17a communicates with the opening 13 via the thin tube 19 and the other port 17b.
Communicates with the opening 25 near the air outlet 10 of the rear case 1b through the narrow tube 21. A series of passages in the thin tubes 19 and 21 and the cover 17 constitute a sub air passage 26.

The refrigerant enters the evaporator 3 through the refrigerant passage 27, the expansion valve 15 and the refrigerant passage 29, exchanges heat with the air flowing into the evaporator 3 from the air inlet 9 to cool the air, and then flows into the refrigerant passage 31. .. The refrigerant passage 31 is returned to the refrigerant passage 27 via a compressor and a condenser (not shown). A temperature sensitive tube 33 is attached to the refrigerant passage 31,
The temperature of the refrigerant flowing out of the evaporator 3 is detected, the throttle opening of the expansion valve 15 is adjusted according to the temperature, and the evaporator 3
Controls the amount of refrigerant supplied to the. From the refrigerant passage 27, the expansion valve 15, the refrigerant passage 29, the evaporator 3 and the refrigerant passage 31, a compressor (not shown),
The circuit of the refrigerant that returns to the refrigerant flow path 27 through the condenser constitutes a refrigeration cycle.

In the above structure, when the fan 5 is rotated by driving the motor 7, the air in the vehicle compartment is taken in through the air inlet 9. The air immediately after being taken in is heat-exchanged and cooled by the evaporator 3. Next, the cool air exiting the evaporator 3 is discharged by the fan 5 from the air outlet 10 of the rear case 1b into the passenger compartment. At this time, due to the flow resistance of the air, the air inlet 9 side from the fan 5 is
The pressure is lower than that on the side.

Therefore, since the static pressure at the opening 13 is lower than the static pressure at the opening 25, the air from the opening 25 to the opening 13 flows in the sub air passage 26 composed of the thin tube 19, the cover 17 and the thin tube 21. Forced flow occurs. That is, fan 5
Part of the air discharged from the
Heat exchange with the expansion valve 15 in the cover 17 through the narrow tube 21,
It is discharged into the front case 1 a through the opening 13 through the thin tube 19.

The temperature of the air introduced from the opening 25 is cooled by the evaporator 3, but the temperature immediately after cooling is almost the same as the temperature of the temperature sensitive tube 33, and further, the case 1
The heat given by the fan 5, the heat given by the fan 5, and the heat given by the thin tube 21 are sufficiently higher than the temperature sensing tube 33.
As a result, the expansion valve 15 can be prevented from falling below the temperature of the temperature sensing cylinder 33, the refrigerant supply amount control to the evaporator 3 by the expansion valve 15 is normally performed, and the cooling failure as the air conditioning system is prevented. To be prevented. [Second Embodiment] Depending on the shapes of the openings 13 and 25, air can be made to flow in the sub air passage 26 in reverse.
An example thereof is shown in FIG. FIG. 2A shows the configuration of the opening 13a provided in the front case 1a between the evaporator 3 and the fan 5. FIG. 2B shows the configuration of the opening 25a provided in the rear case 1b between the fan 5 and the air outlet 10. Figure 2
(C) shows a configuration in which only the opening 13a or the opening 25a is viewed from the front. Both openings 13a, 25a are provided with tubular ribs 51, 53. The opening 13a is arranged so as to face the air flowing in from the evaporator 3, that is, toward the upstream direction, and the opening 25a is arranged in the air outlet 10a.
Direction, that is, toward the downstream direction.

As a result, the dynamic pressure of air is applied to the opening 13a and only static pressure acts on the opening 25a, so that the air flows in the sub air passage 26 contrary to the previous embodiment. That is, the air is sucked into the sub air passage 26 from the opening 13a and is discharged from the opening 25a.

In this case as well, the temperature of the air introduced from the opening 13a is cooled by the evaporator 3, but the temperature immediately after cooling is almost the same as the temperature of the temperature sensing tube 33, and from the case 1 further. The temperature applied to the temperature sensing tube 33 is sufficiently higher due to the heat applied and the heat applied from the thin tube 19. As a result, as in the previous embodiment, the expansion valve 15
Can be prevented from becoming lower than the temperature of the temperature sensitive tube 33,
The refrigerant supply amount control to the evaporator 3 by the expansion valve 15 is normally performed, and the cooling failure as the air conditioning system is prevented.

Further, according to this embodiment, the air in the case 1 is sucked in through the opening 13a and discharged through the opening 25a, so that the air volume as the air conditioning system is maintained and the cooling capacity is further secured. It will be good. Although the cover 17 is separate from the case 1 in each of the above-described embodiments, the cover 17 may be formed integrally with the case 1 to separate the air passage 2 and the sub air passage 26 by a partition wall.

[0020]

[Effect] Since the present invention has the above-mentioned configuration, the expansion valve does not fall below the refrigerant temperature in the temperature sensing cylinder. Therefore,
The expansion valve normally controls the amount of refrigerant supplied to the evaporator, and prevents a cooling failure as an air conditioning system.

[Brief description of drawings]

FIG. 1 is a front view of a first embodiment.

2A and 2B are explanatory views showing a structure of an opening according to a second embodiment, FIG. 2A is a structural explanatory view of an opening between an evaporator and a fan, and FIG. 2B is an explanatory view of an opening between a fan and an outlet. FIG. 3C is a configuration diagram, and FIG. 7C is a diagram illustrating the shape of the opening.

[Explanation of symbols]

1 ... Case, 1a ... Front case, 1b ... Rear case, 2 ... Air passage, 3 ... Evaporator,
5 ... fan, 7 ... motor, 9 ... air inlet,
10 ... Air outlet, 13, 13a ... Opening, 15 ...
..Expansion valves, 17 ... covers, 19, 21 ... thin tubes, 25, 25a ... openings, 26 ... sub air passages,
27, 29, 31 ... Refrigerant passage, 33 ... Temperature sensing tube,
51 ... Cylindrical rib

Claims (2)

[Claims] 1. An expansion valve of a refrigerating cycle is arranged outside the air passage, and an evaporator and a fan of the refrigerating cycle are sequentially arranged inside the air passage from an inlet side to an outlet side of the air passage. As a result, when the fan is driven, in the vehicle air conditioner that cools the vehicle interior air sucked from the inlet of the air passage by the evaporator and discharges it from the outlet into the vehicle interior, An opening is provided in each of the air passage portion between the fan and the air passage portion between the fan and the outlet, and a sub-air passage in which the expansion valve is arranged is provided, so that the space between the both openings is provided. The air conditioner for an automobile capable of causing a flow of air in the sub air passage due to the pressure difference between the two and preventing excessive cooling of the expansion valve arranged in the sub air passage. 2. The sub-air passage opens in an upstream direction of air in an air passage portion between the evaporator and the fan, and in a downstream portion of air in an air passage portion between the fan and the outlet. By being configured to be open, the inside of the sub air passage is opened from the opening of the air passage portion between the evaporator and the fan toward the opening of the air passage portion between the fan and the outlet. Air conditioner for automobiles that allows air to flow.