JP3374769B2 - Vehicle air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual type air conditioner for a vehicle having an air conditioning unit at both the front and the rear of a passenger compartment.

[0002]

2. Description of the Related Art In recent years, with the spread of one-box cars and the like, there is an increasing demand for improving the habitability of the rear seat side space of a vehicle compartment. The number of dual-type vehicle air conditioners equipped with an air conditioning unit is increasing. As such an air conditioner, an air conditioner as shown in FIGS. 2 and 4 is known.

The refrigeration cycle A comprises a compressor 1, a condenser 2,
First and second expansion valves 3, 4, first and second evaporators 5, 6
, And these devices are connected by a refrigerant pipe 9. The first evaporator 5 and the second evaporator 6 are arranged in parallel on the downstream side of the condenser 2, and the first expansion valve 3 and the second evaporator 6 are respectively arranged on the upstream sides of the evaporators 5 and 6. Two expansion valves 4 are arranged.

The first evaporator 5 for cooling the conditioned air includes a first blower 7 for blowing the conditioned air, a heater core (not shown) for heating the conditioned air, and a front air conditioning unit B.
It is installed in. On the other hand, the second evaporator 6 that cools the conditioned air, together with the second blower 8 that blows the conditioned air, is provided with the rear air conditioning unit C provided in the rear ceiling of the vehicle compartment.
It is installed in. The rear-side high-pressure pipe 20 and the rear-side low-pressure pipe 21 that connect the front-side refrigeration cycle and the rear-side refrigeration cycle are housed in the vehicle compartment side wall surface, and
It is routed to pass under the floor. In addition,
In order to prevent the refrigerant sucked into the compressor 1 from flowing into the rear low-pressure pipe 21 during the independent operation of the front air conditioning unit B, the refrigerant downstream end of the rear low-pressure pipe 21 is connected to the front low-pressure pipe 22 from above. It has a piping structure for connection.

[0005]

By the way, in such an air conditioner, the independent operation of the front air conditioning unit B and the simultaneous operation of both the front and rear air conditioning units B and C are performed in the rear air conditioning unit C. The operation is performed by switching the operation of the second blower 8 provided in the. Therefore, when only the front air conditioning unit B is operated independently, the second blower 8 is turned off, and the evaporation of the refrigerant in the second evaporator 6 is suppressed. Therefore, the second expansion valve 4 is set to the second evaporator. The amount of refrigerant flowing into 6 is controlled so as to decrease.

As described above, in the conventional air conditioner, the rear low-pressure pipe 21 has a piping structure that extends upward at the refrigerant downstream end. Therefore, as the amount of refrigerant flowing into the second evaporator 6 decreases, the lubricating oil for compressor protection that is enclosed in the refrigeration cycle together with the refrigerant easily becomes stagnant in the refrigerant circuit of the rear air conditioning unit C. . As described above, when the amount of lubricating oil returning from the second evaporator 6 to the compressor 1 is reduced, there is a problem that the durability of the compressor 1 is adversely affected.

In view of the above points, an object of the present invention is to reduce stagnation of lubricating oil on the rear air conditioning unit side.

[0008]

In order to solve the above-mentioned problems, according to the invention of claims 1 to 4, in the refrigerant pipe connecting the downstream side of the second evaporator to the merging portion, a substantially horizontal direction. It is characterized in that the refrigerant pipe arranged at is inclined at a predetermined angle so that the refrigerant upstream side is higher than the refrigerant downstream side. With such a piping structure, the second
The lubricating oil contained in the refrigerant existing on the refrigerant downstream side of the expansion valve is sent to the refrigerant downstream side, that is, the confluent portion by gravity. The lubricating oil sent to the confluence section is
It merges with the refrigerant that has passed through the evaporator and returns to the compressor. Thus, according to the present invention, even if the amount of the refrigerant flowing into the second evaporator via the second expansion valve is reduced, the lubricating oil is stagnated in the refrigerant pipe on the downstream side of the second expansion valve. Instead, it can be returned to the compressor.

According to the third aspect of the invention, of the refrigerant pipes connecting the downstream side of the first evaporator to the merging portion, the refrigerant pipes arranged in a substantially horizontal direction are inclined at an angle of 0.
It is desirable that it is larger than 10 ° and is 10 ° or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A vehicle air conditioner according to the present invention will be described below with reference to the drawings.

The refrigeration cycle A includes a compressor 1, a condenser 2 and a front side evaporator 5 (the first in the claims.
No. 2), a rear evaporator 6 (second evaporator in claims), first and second expansion valves 3 and 4, and a refrigerant pipe 9 connecting these functional parts. The compressor 1 constitutes the compressor of the present invention, is arranged in the engine room of the vehicle (left side in FIG. 1), receives the driving force from the engine of the vehicle, and compresses the refrigerant to generate high temperature and high pressure. It is used as a vapor phase refrigerant. And compressor 1
Is controlled to be turned on and off according to conditions by a power interrupter, specifically, a magnetic clutch (not shown).

The condenser 2 exchanges heat between air and the vapor-phase refrigerant by condensing and liquefying the vapor-phase refrigerant by receiving high-temperature and high-pressure vapor-phase refrigerant blown by a cooling fan (not shown) from the compressor 1. Is. Further, the condenser 2 is arranged in a position in the engine room of the vehicle where the traveling wind of the vehicle is received. In the condenser 2, the condensed and liquefied refrigerant is separated into a gas phase refrigerant and a liquid refrigerant,
A receiver 10 that temporarily stores a liquid coolant is integrally provided.

The first and second expansion valves 3 and 4 are for expanding and reducing the pressure of the liquid refrigerant, and the front side of the evaporators 5 and 6 of the front side and the rear side evaporators 5 and 6 according to the temperature of the refrigerant immediately downstream of the refrigerant. , And refrigerant amount varying means 3a, 4a for determining the amount of refrigerant sent to the rear side evaporators 5, 6.
The front and rear evaporators 5 and 6 are the first and second
The refrigerant that has been cooled by decompressing and expanding by the expansion valves 3 and 4 and the first and second blowers 7 and 8 arranged in the duct (not shown) of the vehicle air conditioner. By exchanging heat with the air flow, the refrigerant is vaporized and vaporized to cool the air flow.

Reference numeral B denotes a front air conditioning unit for air conditioning the front portion of the vehicle compartment, which is disposed below the front panel (not shown) disposed in the vehicle compartment between the engine room and the vehicle compartment. . Inside the front air conditioning unit B, a front side evaporator 5, a first blower 7, etc. are arranged. The first blower 7 sucks the vehicle interior air (inside air mode) or the vehicle exterior air (outside air mode) selected by an inside / outside air switching unit (not shown) provided in the vehicle air conditioner, and a front side evaporator. Blow to 5. The refrigerant flowing in the front side evaporator 5 exchanges heat with the air in the vehicle compartment or the air outside the vehicle compartment, and cools the air blown out from the air outlet provided in the front (front side) of the vehicle compartment.

Reference numeral C denotes a rear air conditioning unit for air conditioning the rear portion of the passenger compartment, which is arranged on the wall portion on the rear seat side (rear side) of the vehicle. Inside the rear air conditioning unit C, a rear evaporator 6 and a second blower 8 for blowing air to the rear evaporator 6 are arranged. The refrigerant flowing in the rear evaporator 6 exchanges heat with the air in the vehicle compartment blown by the second blower 8 to cool the air blown out from the rear seat outlet. The operation of the second blower 8 is switched by an occupant operating an operation panel (not shown) installed in the passenger compartment. The rear air conditioning unit C
The operation of is switched by the operation of the second blower 8.

The refrigerant pipe 9 is for connecting the above-mentioned functional parts, and a discharge side refrigerant pipe 9a for connecting the discharge side of the compressor 1 and the refrigerant upstream side of the condenser 2 and the refrigerant downstream of the condenser 2. Side, the liquid side refrigerant pipe 9b connecting the first and second expansion valves 7, 8 to the refrigerant upstream side, and the refrigerant downstream side of the front side evaporator 5 and the rear side evaporator 6 and the suction side of the compressor 1. The suction side refrigerant pipe 9 for joining the vapor phase refrigerant discharged from the refrigerant downstream side of the front side evaporator 5 and the rear side evaporator 6
It consists of c and. The liquid-side refrigerant pipe 9b includes a front-side high-pressure pipe 9b1 connected to the upstream side of the first expansion valve 3 and a rear-side high-pressure pipe 9b2 connected to the second expansion valve 4 in the branch portion 11. The first expansion valve 3 and the front side evaporator 5, and the second expansion valve 4 and the rear side evaporator 6 are respectively connected between the refrigerant downstream side of the condenser 2 and the suction side of the compressor 1. They are arranged in parallel. On the other hand, in the suction-side refrigerant pipe 9c, a front-side low-pressure pipe 9c1 connected to the refrigerant downstream side of the front-side evaporator 5 and a rear-side low-pressure pipe 9c2 connected to the refrigerant downstream side of the rear-side evaporator 6 are joined together. It has a structure that joins in. In the merging section 12,
The downstream end of the rear low-pressure pipe 9c2 is connected to the front low-pressure pipe 9c1 from above so that the refrigerant does not flow back to the rear evaporator 6 when the front air conditioning unit B is operated independently. Subsequently, the rear low-pressure pipe 9c2, which is a main part of the present invention, will be described. The rear side low-pressure pipe 9c2 is the first
It is composed of a pipe 13, a second pipe 14, and a third pipe 15. The first pipe 13 is connected to the outlet side of the rear evaporator 6 and extends in a substantially horizontal direction. The second pipe 14 is connected to the first pipe 13 via a joint, and extends from the upper side to the lower side in a substantially vertical direction. The third pipe 15 is connected to the second pipe 14 via a joint, and joins the front low-pressure pipe 9c2 at the joining portion 12. The third pipe 15 is arranged so as to pass below the floor in the vehicle compartment, and most of it extends in a substantially horizontal direction from the rear of the vehicle to the front. The first pipe 13 and the third pipe 15 extending in the substantially horizontal direction have a predetermined angle θ (for example, greater than 0 ° and less than or equal to 10 ° so that the refrigerant upstream side is above the refrigerant downstream side). Angle).

The operation of this embodiment will be described below.

By operating the operation panel installed in the passenger compartment by the occupant, the front air conditioning unit B can be operated independently.
Simultaneous operation of both the front and rear air conditioning units B and C is switched. When the simultaneous operation of both the front and rear air conditioning units B and C is selected, the first and second blowers 7 and 8 are turned on, and the front air conditioning unit B has the first
The blower 7 blows conditioned air, and in the rear air conditioning unit C, the second blower 8 blows conditioned air (air in the passenger compartment). The refrigerant passing through the evaporators 5 and 6 absorbs heat from the blown conditioned air and evaporates. As a result, the conditioned air is cooled and becomes cold air, which is blown out from each of the air conditioning units B and C into the vehicle interior. On the other hand, when the independent operation of the front air conditioning unit B is selected, the first blower 7 is turned on, the second blower 8 is turned off, and the blowing of cool air to the rear of the vehicle compartment is stopped. By turning off the second blower 8, the evaporation of the refrigerant in the rear evaporator 6 is suppressed, and the refrigerant temperature at the outlet side of the rear evaporator 6 decreases. As a result, the second expansion valve 8 is connected to the rear evaporator 6
The amount of the refrigerant flowing into is controlled so as to decrease.

By the way, in the refrigeration cycle 1, in order to lubricate the sliding portion of the compressor 1 and improve the durability of the compressor 1, a predetermined amount of lubricating oil is enclosed together with the refrigerant. According to the present embodiment, of the rear low-pressure pipe 9c2, which is the refrigerant pipe from the refrigerant downstream side of the rear evaporator 6 to the confluence portion 12, the first and third pipes 13 and 15 extending in the substantially horizontal direction. Is inclined so that the refrigerant upstream side (that is, the rear evaporator 6 side) is higher than the refrigerant downstream side (that is, the merging portion 12 side), so that the lubricating oil sealed in the refrigerant is gravity. Then, it moves downward and is sent to the merging section 12. Junction 1
The lubricating oil sent to No. 2 is the low pressure piping 9c on the front side.
It is sent to the compressor 1 together with the refrigerant flowing in 1. As described above, the first and third refrigerant pipes 1 extending in the substantially horizontal direction
By tilting 3, 15 the rear air conditioning unit C
Even if the engine is stopped, the lubricating oil is supplied to the second expansion valve 4
The refrigerant can be returned to the compressor 1 without stagnating on the downstream side. In addition, when the front air conditioning unit B is operated independently,
Since the lubricating oil passes through the first to third refrigerant pipes 13 to 15 in a state of being mixed with the liquid-phase refrigerant, the viscosity is smaller than that of the lubricating oil alone, and the lubricating oil can be easily mixed with the first refrigerant.
Passage can be passed through the first to third refrigerant pipes 13 to 15.

Further, since the first and third refrigerant pipes 13 and 15 are pipes which pass under the floor in the vehicle compartment, the inclination angle thereof is larger than 0 ° and 10 ° or less. It is desirable for handling.

Next, the present inventor compared the experimental results of comparing the oil circulation rate of the front air conditioning unit B in the independent operation of the conventional piping structure and the refrigeration cycle apparatus of the piping structure shown in this embodiment. Shown in the figure. The circulation rate of the lubricating oil is measured by an oil circulation rate meter (indicated by reference numeral 16) provided on the refrigerant downstream side of the condenser 2 and the independent operation of the front air conditioning unit B is started (second blower 8). Was turned off) was measured. The inclination angle θ of the first and third pipes in the experimental example was 5 °.

As shown in FIG. 3, immediately after the start of the independent operation of the front air conditioning unit B, the oil circulation rate is almost the same as in the conventional example and the present embodiment. However, with the passage of time, in the conventional example, the circulation rate of the lubricating oil decreases, whereas in the present embodiment, no great fluctuation is observed. That is, by inclining the first and third pipes 13 and 15 extending in the substantially horizontal direction, the returning amount of the lubricating oil can be secured regardless of the operating state of the rear air conditioning unit C.

In the embodiment described above, the rear low-pressure pipe is connected to the first to third pipes, but the refrigerant pipe extending in the substantially horizontal direction is inclined at a predetermined angle. Any structure may be used, and the number of refrigerant pipes forming the rear low-pressure pipe is not particularly limited.

In the present embodiment, the refrigerant pipe that is inclined at a predetermined angle may be a refrigerant pipe that extends in a substantially horizontal direction, and the direction in which the pipe extends is shown in the above embodiment. It is not limited to the vehicle front-rear direction.

Further, in the present embodiment, the air conditioner in which the rear air conditioner unit is housed in the wall surface of the rear seat has been described, but it is also possible to apply the air conditioner in which the rear air conditioner unit is arranged in the ceiling. The position where the rear air conditioning unit is provided is not particularly limited.

[Brief description of drawings]

FIG. 1 is a diagram showing a piping structure in the present invention.

FIG. 2 is a schematic diagram showing a refrigeration cycle in the present invention.

FIG. 3 is a diagram showing an experimental result comparing an embodiment of the present invention with a conventional example.

FIG. 4 is a diagram showing a conventional piping structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Condenser ... 3 ... 1st expansion valve, 4 ... 2nd expansion valve, 5 ... Front side evaporator (1st evaporator),
6 ... Rear side evaporator (2nd evaporator), 7 ... 1st air blower, 8 ... 2nd air blower, 9 ... Refrigerant piping, 12 confluence part, 1
6 ... Vehicle interior heat exchanger, S ... Adsorbent

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60H 1/32 621 F25B 5/02 B60H 1/00 F25B 1/00 B60H 1/32 613 F25B 1/00 387 F25B 43/02

Claims (4)

(57) [Claims] 1. A compressor for compressing a refrigerant, a condenser for condensing and liquefying the refrigerant compressed by the compressor, a first expansion valve for decompressing the refrigerant condensed and liquefied by the condenser, A first evaporator that evaporates the refrigerant whose pressure has been reduced by the first expansion valve and cools the air that is blown by the first blower; and a first evaporator that is arranged in parallel with the first expansion valve and that is condensed by the condenser. A second expansion valve for decompressing the liquefied refrigerant,
A second evaporator that evaporates the refrigerant decompressed by the second expansion valve and cools the air blown by the second blower 8 and a refrigerant pipe that connects these are provided. An air conditioner having a refrigeration cycle in which a refrigerant evaporated in the first evaporator and a refrigerant evaporated in the second evaporator join together, wherein the refrigerant downstream side of the second evaporator is from the joining portion. Of the refrigerant pipe, the refrigerant pipe extending substantially horizontally is inclined at a predetermined angle such that the refrigerant upstream side is higher than the refrigerant downstream side. 2. The vehicle air conditioner according to claim 1, wherein the refrigerant pipe extending in the substantially horizontal direction is a refrigerant pipe extending in the vehicle front-rear direction or the vehicle left-right direction. 3. The vehicle air conditioner according to claim 1 or 2, wherein the inclination angle of the refrigerant pipe is greater than 0 degree and 10 degrees or less. 4. The first evaporator is arranged in a front air conditioning unit for air conditioning the front of the vehicle compartment, and the second evaporator is arranged in a rear air conditioning unit for air conditioning the rear of the vehicle compartment. The air conditioner according to any one of claims 1 to 3, wherein: