JPH1120463A - Dual air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the circulation rate of oil to a compressor so as to prevent seizure of the compressor by preventing oil from flowing into low pressure piping, extended from a rear side evaporator, from low pressure piping extended from a front side evaporator. SOLUTION: Low pressure piping extended from a front side evaporator 9 is descended while low pressure piping 36 extended from a rear side evaporator 36 is risen upward, and both low pressure piping 34, 36 are joined each other in a lower position than the front side evaporator 9 so that refrigerant flows. The low pressure piping 28 extended to the compressor side from a confluence part 37 is risen upward, and a solenoid valve arranged at an intermediate part of high pressure piping of a rear side air conditioner is opened even in the case of operating only a front side air conditioner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual air conditioner for a vehicle comprising a front air conditioner for air conditioning a driver's seat and a passenger seat (front seat) and a rear air conditioner for air conditioning a rear seat (rear seat). About.

[0002]

2. Description of the Related Art In vehicles such as one-box cars,
Generally, a dual air conditioner is used to appropriately air-condition the front seat side and the rear seat side. This dual air conditioner is equipped with, for example, a front air conditioner for air conditioning the front seat side and a rear air conditioner for air conditioning the rear seat side.The cooling cycle of both air conditioners includes a compressor, a condenser, and a liquid. A common tank is used, and the expansion valve and the evaporator for the front air conditioner and the expansion valve and the evaporator for the rear air conditioner are connected in parallel by piping.

When the rear air conditioner is arranged under the floor of the vehicle, the rear evaporator and the low-pressure pipe extending from the evaporator are lower than the front evaporator and the compressor. In order to merge the low-pressure pipe 101 extending from the rear evaporator 100 with the low-pressure pipe 103 extending from the front evaporator 102, it is necessary to raise the low-pressure pipe 101 extending from the rear evaporator 100 to a high position. .

On the other hand, lubricating oil is provided inside the compressor to protect the compressor from seizure, but this oil inevitably flows out of the compressor and flows in the cooling cycle together with the refrigerant. Things.

[0005] In this case, there is no problem if the oil flowing out of the compressor is appropriately returned to the compressor. However, in a single operation in which the dual air conditioner operates only the front air conditioner, the oil has a large specific gravity. As shown, for example, a part of the low-pressure pipe 101 flows from the junction 104 of the low-pressure pipe 103 extending from the front-side evaporator 102 and the low-pressure pipe 101 extending from the rear-side evaporator 100 to the lower-level low-pressure pipe 101. Of these, it tends to accumulate at the site from the front side, which is bent upward, to the evaporator (the oil stagnation of about 53% of the total amount has been confirmed by experiments).
Therefore, since the circulation rate of the oil is low, the amount of the oil recirculated to the compressor decreases with the passage of time. Therefore, it is difficult to sufficiently prevent the seizure of the compressor.

On the other hand, a low-pressure pipe extending from a front-side evaporator and a low-pressure pipe extending from a rear-side evaporator are joined at a high position at a steep angle, as in a refrigeration system disclosed in Japanese Utility Model Publication No. 6-45810. It is also conceivable to form a substantially Y-shaped piping unit by joining a low-pressure pipe extending to the compressor further below. According to the configuration of this piping unit, it is difficult for oil to flow from the low-pressure pipe extending from the front-side evaporator to the low-pressure pipe extending from the rear-side evaporator, and even if oil flows in, the oil returns to the merging section due to gravity. Therefore, it is possible to increase the oil circulation rate because the oil easily flows into the low pressure pipe extending to the low pressure pipe.

[0007]

However, in the configuration of the refrigerating apparatus disclosed in the above publication, when such a piping unit is installed, if the low-pressure pipe extending to the compressor is inclined toward the rear evaporator, Since the low-pressure pipe extending from the rear-side evaporator has a smaller inclination angle with respect to the installation surface of the air conditioner, oil flows from the low-pressure pipe extending from the front-side evaporator into the low-pressure pipe extending from the rear-side evaporator, and stagnates. There is a possibility that it will happen.

For this reason, in the installation of the junction of the low-pressure pipe extending from the front-side evaporator, the low-pressure pipe extending from the rear-side evaporator, and the low-pressure pipe extending to the compressor, the positioning in the vertical direction must always be performed with high accuracy. Required, and the piping work becomes complicated. In addition, since a bracket is required to fix the piping unit so that the piping unit does not tilt due to vibration of the vehicle or the like, the number of parts is reliably increased.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to prevent oil from flowing from a low-pressure pipe extending from a front-side evaporator to a low-pressure pipe extending from a rear-side evaporator during single operation of a front-side air conditioner. It is an object of the present invention to provide a dual air conditioner for a vehicle which can be achieved, and can perform the piping work easily and can suppress an increase in the number of parts.

[0010]

According to the dual air conditioner for a vehicle according to the present invention, a front air conditioner having a front evaporator as a cooling means in a front air conditioner duct and a rear air conditioner in a rear air conditioner duct are provided. And a rear-side air conditioner having a rear-side evaporator as a cooling means, a compressor and a condenser are shared, and the rear-side evaporator and the front-side expansion valve connected thereto are connected to the rear-side evaporator and the rear-side evaporator. A cooling cycle having a configuration in which rear-side expansion valves are connected in parallel with pipes, wherein a low-pressure pipe extending from the front-side evaporator is lowered downward from a high position, and a low-pressure pipe and a rear-side evaporator extending from the front-side evaporator. Extending the low-pressure pipe and the front-side evaporator The low pressure pipe extending from the junction to the compressor side is raised upward, and an opening / closing means for controlling the flow rate of the refrigerant in the middle of the high pressure pipe extending to the rear air conditioner is provided. The opening / closing means is always opened even when only the front-side air conditioner is operated (claim 1).

Thus, in the so-called single operation in which only the front air conditioner is operated, the refrigerant flowing out of the front evaporator and the oil contained therein pass through the low pressure pipe and have a lower pressure than the compressor and extend from the rear evaporator. Since the oil flows to the junction where the pipe is located at the same position, there is no danger of oil falling into the low-pressure pipe extending from the rear evaporator, and the refrigerant flows from the low-pressure pipe extending from the rear evaporator to the junction at the same height. This prevents the oil from flowing from the junction to the low-pressure pipe extending from the rear evaporator.

The low-pressure pipe extending from the rear evaporator is made substantially horizontal, and the lowermost part of the low-pressure pipe extending from the front evaporator is made substantially horizontal, so that the low-pressure pipe extending from the rear evaporator is made horizontal. The refrigerant flowing along the horizontal portion of the low-pressure pipe extending from the front-side evaporator may be joined in the direction in which the refrigerant collides, and the low-pressure pipe extending directly from the junction to the compressor side may be raised upward. ).
As a result, the oil flowing from the low-pressure pipe extending from the front-side evaporator has a reduced flow velocity in the horizontal portion of the low-pressure pipe extending from the front-side evaporator, and also joins with the refrigerant flowing from the low-pressure pipe extending from the rear-side evaporator. Therefore, it is more difficult to flow toward the low-pressure pipe extending from the rear-side evaporator.

Further, the low-pressure pipe extending from the rear-side evaporator is made substantially horizontal, and the lowermost part of the low-pressure pipe extending from the front-side evaporator is joined to this horizontal portion so that the flow of the refrigerant in the same direction can be obtained. A low-pressure pipe extending toward the compressor downstream from the section may be raised upward (claim 3). As a result, the oil flowing from the low-pressure pipe extending from the front-side evaporator flows over the junction to the low-pressure pipe extending from the rear-side evaporator. Is reduced, and the flow of refrigerant from the low-pressure pipe extending from the rear-side evaporator is reversed. Therefore, the refrigerant hardly flows toward the low-pressure pipe extending from the rear-side evaporator.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, a dual air conditioner 1 for a vehicle shown in FIG. 1 has a front air conditioner 2 for air conditioning of at least a driver seat and a passenger seat side (front seat side), and a rear seat side (rear seat side). And a rear air conditioner 3 for air conditioning.

The front air conditioner 2 is disposed, for example, on the inside of the vehicle interior of the fire board. The front air conditioner 2 has an outside air inlet 5 and an inside air inlet 6 which are opened at the most upstream side of the front air conditioner duct 4. 5 and an inside air inlet 6 are selectively opened as appropriate to have an intake door 7 for setting an outside air mode, an inside air circulation mode, and a mixing mode. A blower 8 is provided on the downstream side. The blower 8 is usually a sirocco fan driven by a brush rester or the like.
There is no particular limitation as long as air is sucked in from above and blown downstream.

An evaporator (a front-side evaporator) 9 which constitutes a part of a cooling cycle is disposed downstream of the blower 8, and a heater core using cooling water of a running engine as a heat source is provided downstream of the evaporator 9. 10 are arranged. On the upstream side of the heater core 10, there is provided a mix door 11 for diverting air that has passed through the evaporator 9 into air that passes through the heater core 10 and air that bypasses the heater core 10.

A differential air outlet 12, a vent air outlet 13, and a foot air outlet 14 are opened at the most downstream side of the air conditioning duct 4, and are selectively opened by a blow mode door 15 in a manual mode or an automatic mode. Is what is done.

In the front-side air conditioner 2 having the above-described structure, the air selected by the intake door 7 is sucked by driving the blower 8 and is blown to the downstream side of the air-conditioning duct 4. The air is first cooled by passing through the evaporator 9, and is divided into air passing through the heater core 10 and air bypassing the heater core 10 depending on the opening degree of the mix door 11. The air heated through the heater core 10 and the cooled air that bypasses the heater core 10 are mixed in a space downstream of the heater core 10 to become air temperature-controlled to a desired temperature. Outlets 12, 13, 1 selected by 15
4 blows out into the vehicle interior to control the temperature in the interior of the vehicle interior, especially on the front seat side.

The rear air conditioner 3 is disposed, for example, under the floor of a vehicle. Only the inside air inlet 17 is opened at the most upstream side of the rear air conditioning duct 16, and a blower is provided downstream of the inside air inlet 17. 18. An evaporator (rear evaporator) 19 that constitutes a part of a cooling cycle is arranged downstream of the blower 18, and further downstream of the evaporator 19 is a heater core 20 that uses cooling water of a traveling engine as a heat source.
Is arranged. The air that has passed through the evaporator 19 is provided upstream of the heater core 20 with the heater core 2.
A mix door 21 is provided to divide air into air passing through zero and air bypassing.

An upper air outlet 22 and a lower air outlet 23 connected to a duct (not shown) are opened at the most downstream side of the air conditioning duct 16, and the upper air outlet 22 and the lower air outlet 23 can be selected. This is performed by moving the blow mode door 24 in the manual mode or the automatic mode. In the rear air conditioner 3 having the above configuration, the front air conditioner 2
By the same operation as that described above, the temperature of the space in the passenger compartment, especially on the rear seat side, is controlled.

The cooling cycle of the vehicular dual air conditioner 1 having the above-described configuration includes a common path 28 formed by connecting a compressor 25 rotated by a traveling engine, a condenser 26, and a receiver tank 27 in series with a pipe. A front path 30 formed by connecting the front expansion valve 29 and the front evaporator 9 in series with a pipe, and a rear path formed by connecting the rear expansion valve 31 and the rear evaporator 19 with a series pipe. With 32,
Front side expansion valve 2 constituting the front side path 30
9 and the front side evaporator 9 and the rear side path 32
-Side expansion valve 31 and rear-side evaporator 1 constituting
9 is connected to the common path 28 so as to be in parallel. In the rear passage 32, an electromagnetic valve 33 that can control the amount of refrigerant sent to the rear expansion valve 31 and the rear evaporator 19 is disposed upstream of the rear expansion valve 31.

In this cooling cycle, during the dual operation in which both the front air conditioner 2 and the rear air conditioner 3 are operated, the solenoid valve 33 is naturally open and the gas refrigerant compressed by the compressor 25 is discharged. The heat is condensed by being radiated by the condenser 26 and is separated into gas and liquid by the liquid tank 27 to form a high-pressure liquid refrigerant.
0 and the rear side path 32. High-pressure liquid refrigerant is
The refrigerant passes through the expansion valves 29 and 31 and adiabatically expands to become a low-pressure liquid refrigerant. Further, the refrigerant absorbs heat and evaporates in the evaporators 9 and 19 to become a gas refrigerant and returns to the compressor 25.

On the other hand, in the single operation in which only the front air conditioner 2 is operated, the oil for lubricating the compressor 25 flows backward from the low pressure side of the front passage 30 to the low pressure side of the rear passage 32, and the rear passage 32 There is a possibility that oil stagnation may occur on the low pressure side, but in order to solve this problem, the present invention has devised the following.

First, the solenoid valve 33 is in an open state even during the single operation, except when the rear evaporator 19 is in thermostat. For this reason, the refrigerant circulates through the rear path 32 even though it is a small amount, so that the flow as shown by the arrow in FIG. 2 can always be ensured.

As shown in FIG. 2, the low-pressure pipe 34 constituting the low-pressure side of the front-side path 29 descends from the front-side evaporator 9 through the through-hole of the fire board 35, and then descends downward. 9 and has a horizontal portion 34a that extends horizontally at a position lower than 9. In this embodiment, the low-pressure pipe 36 constituting the low-pressure side of the rear-side path 32 has, for example, the rear-side air conditioner 3 disposed below the floor of the vehicle, and therefore, the joint portion with the rear-side evaporator 19 is the lowest. It has a horizontal portion 36a which rises upward as it goes to the compressor 25 side in the middle and extends horizontally from a position where it rises to the same height as the horizontal portion 34a of the low-pressure pipe. Therefore, the horizontal portion 36a of the low-pressure pipe is also lower than the front-side evaporator 9.

The horizontal portion 34a of the low-pressure pipe and the horizontal portion 36a of the low-pressure pipe extend in opposite directions. Therefore, at a predetermined position, the tip of the horizontal portion 34a of the low-pressure pipe and the horizontal portion 36a of the low-pressure pipe are connected. The leading end portion joins to form a joining portion 37. This confluence part 37 is of course also a horizontal part 36a.
Is also lower than the front side evaporator 9. A low-pressure pipe 38 that constitutes the common path 28 extends directly upward from the junction 37, and a distal end of the low-pressure pipe 38 is connected to the compressor 25.

According to the above configuration, the refrigerant flowing out of the front side evaporator 9 and the oil contained therein are:
It goes down to the horizontal part 34a through the low pressure pipe 34. In this case, the oil flows over the low pressure pipe 36 over the junction 37.
However, while colliding with the refrigerant flowing from the horizontal portion 36a of the low-pressure pipe 36 to the merging portion 37, the horizontal portion 3
Since the flow velocity of the refrigerant is reduced by flowing through the 4a and the horizontal portion 36a, the flow is obstructed. As a result, the oil accumulates near the junction 37 of the horizontal portion 34a, which is the lowest position of the low-pressure pipe 34, is returned to the compressor 25 through the low-pressure pipe 38 by the suction force of the compressor 25, and the oil is circulated to the compressor 25. The rate improves.

The construction of the low-pressure pipes 34, 36 and 38 is not limited to that shown in FIG. 2, and the oil which has descended from the low-pressure pipe 34 to the lowest horizontal portion 34a has a low pressure. It is sufficient that the flow through the pipe 36 can be suppressed by using the refrigerant flowing from the low-pressure pipe 36 to the junction 37, and another configuration example that can obtain such an operation and effect is shown in FIG.

The low-pressure pipe 34 constituting the low-pressure side of the front-side path 29 passes through the through-hole of the fire board 35 from the front-side evaporator 9 and then descends to a position lower than the evaporator 9. . In addition, the low-pressure pipe 36 constituting the low-pressure side of the rear-side path 32 is
Also in this embodiment, the rear air conditioner 3 is located below the floor of the vehicle, and therefore, is at the lowest position.
It has a horizontal portion 36a extending in the horizontal direction from a position raised to the same height as the tip of the low-pressure pipe 34. Therefore,
This horizontal portion 36a is also lower than the evaporator 9.

The horizontal portion 36a of the low-pressure pipe extends toward the tip of the low-pressure pipe 34 so that the low-pressure pipe 34
And a merging portion 37 is formed in a direction substantially orthogonal to the above. The low-pressure pipe 38 forming the common path 28 has a horizontal portion 38a extending horizontally from the junction 37 and extends upward from the downstream end of the horizontal portion 38a to the compressor 25 located at a higher position. The tip is connected.

According to the above configuration, the refrigerant flowing out of the front-side evaporator 9 and the oil contained therein are:
It goes down through the low-pressure pipe 34 to the junction 37 with the horizontal part 36a of the low-pressure pipe, and in this case, the horizontal part 36a of the low-pressure pipe
However, the flow of the refrigerant is countered to the flow of the refrigerant from the direction of the horizontal portion 36a of the low-pressure pipe, and the flow rate of the refrigerant is reduced by flowing through the horizontal portion 36a. As a result, the oil flows into the junction 3
7 is collected in the horizontal part 36a of the low-pressure pipe or the horizontal part 38a of the low-pressure pipe, and is returned to the compressor 25 through the low-pressure pipe 38 by the suction force of the compressor 25, so that the oil circulation rate to the compressor 25 is improved.

Further, as shown in FIG. 4, in the configuration shown in FIG. 3, the horizontal portions 36a, 38a of the low-pressure pipe are
A step may be formed by extending upward after extending horizontally from the junction 37 and further extending in the horizontal direction. According to this configuration, it is possible to prevent the oil sent from the low-pressure pipe 34 from flowing into the horizontal section 36a of the low-pressure pipe at the step portion of the horizontal section 36a.
Oil is returned to the compressor 25 more favorably.

[0034]

As described above, according to the dual air conditioner for a vehicle of the first aspect, the refrigerant flowing out of the front side evaporator and the oil contained therein are prevented from flowing into the low pressure pipe extending from the rear side evaporator. As a result, the circulation rate of the oil flowing through the cooling cycle is increased, the seizure of the compressor can be prevented well, and the vertical direction of the low-pressure pipe extending from the front-side evaporator and the low-pressure pipe extending from the rear-side evaporator is taken into consideration to the left. Since there is no need to do so, piping work at the merging portion is simple, and a fixture for preventing inclination of the piping at the merging portion can be eliminated, thereby suppressing an increase in the number of parts.

According to the dual air conditioner for a vehicle according to the second aspect, the flow velocity is reduced in the horizontal portion of the low pressure pipe extending from the front evaporator, and the refrigerant flowing from the low pressure pipe extending from the rear evaporator is removed. Since the collision occurs at the junction, it is further difficult to flow toward the low-pressure pipe extending from the rear-side evaporator, so that the circulation rate of oil flowing through the cooling cycle can be further increased.

Further, according to the dual air conditioner for a vehicle according to the third aspect, the oil flowing from the low-pressure pipe extending from the front-side evaporator flows beyond the junction to the low-pressure pipe extending from the rear-side evaporator. The flow rate is reduced due to the horizontal portion of the low-pressure pipe extending from the rear evaporator, and the flow is directed to the low-pressure pipe extending from the rear evaporator because the flow is counter to the flow of the refrigerant from the low-pressure pipe extending from the rear evaporator. Since it becomes difficult, the circulation rate of the oil flowing through the cooling cycle can be further increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the overall configuration of a vehicle dual air conditioner according to the present invention.

FIG. 2 is a partial explanatory view showing a configuration of a low-pressure side pipe constituting a common route, a front route, and a rear route of the vehicle dual air conditioner according to the first embodiment.

FIG. 3 is a partial explanatory diagram showing a piping configuration of an embodiment different from the low-pressure piping that constitutes the common path, the front path, and the rear path shown in FIG. 2;

FIG. 4 is a partial explanatory view showing another embodiment in which a step is formed in a horizontal portion near a merging portion.

FIG. 5 is a partial explanatory view showing a configuration of a low-pressure side pipe constituting a common path, a front path, and a rear path of the conventional dual air conditioner for a vehicle according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dual air-conditioner for vehicles 2 Front-side air-conditioner 3 Rear-side air-conditioner 4 Air-conditioning duct (front-side air-conditioning duct) 5 Outside air inlet 6 Inside-air inlet 7 Intake door 9 Evaporator (front-side evaporator) 16 Air-conditioning duct (rear-side air-conditioning duct) 17 Inside air inlet 18 Blower 19 Evaporator (Rear evaporator) 25 Compressor 28 Common path 29 Expansion valve (Front side expansion valve) 30 Front side path 31 Expansion valve (Rear side expansion valve) 32 Rear side path 33 Solenoid valve 34 Low pressure pipe 34a Horizontal section 36 Low pressure pipe 36a Horizontal section 37 Converging section 38 Low pressure pipe

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsuyoshi Baba 39, Higashihara, Chiyo, Odai-gun, Osato-gun, Saitama

Claims (3)

[Claims] 1. A front air conditioner having a front evaporator as a cooling means in a front air conditioning duct, and a rear air conditioner having a rear evaporator as a cooling means in a rear air conditioning duct. A vehicle having a cooling cycle in which a compressor and a condenser are shared, and the rear evaporator and the rear expansion valve connected thereto are connected in parallel to the front evaporator and the front expansion valve connected thereto. In the dual air conditioner, the low-pressure pipe extending from the front-side evaporator is lowered downward from a high position, and the refrigerant flows through the low-pressure pipe extending from the front-side evaporator and the low-pressure pipe extending from the rear-side evaporator at a lower level than the front-side evaporator. Merge and take While raising the low-pressure pipe extending from the flow section to the compressor side upwardly, an opening / closing means for controlling the flow rate of the refrigerant is arranged in the middle of the high-pressure pipe extending to the rear air conditioner, even when only the front air conditioner is operated. A dual air conditioner for a vehicle, wherein the opening / closing means is opened. 2. The horizontal portion of the low-pressure pipe extending from the rear evaporator by making the low-pressure pipe extending from the rear evaporator substantially horizontal and making the lowermost part of the low-pressure pipe extending from the front evaporator substantially horizontal. And the horizontal part of the low-pressure pipe extending from the front-side evaporator is joined in the direction in which the flowing refrigerant collides, and the low-pressure pipe extending from the junction directly to the compressor side is raised upward. The dual air conditioner for vehicles as described. 3. The low-pressure pipe extending from the rear-side evaporator is made substantially horizontal, and the lowermost portion of the low-pressure pipe extending from the front-side evaporator is joined to this horizontal portion so that the flow of the refrigerant in the same direction can be obtained. The dual air conditioner for a vehicle according to claim 1, wherein a low-pressure pipe extending toward the compressor on the downstream side from the part is raised upward.