JPH081129Y2 - Vehicle air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an air conditioner for a vehicle such as a bus.

(Prior Art) An air conditioner for a vehicle that sends air to a vehicle interior to an evaporator of a refrigerant compression refrigeration cycle to cool the air and then re-introduces the air into the vehicle interior to cool the vehicle interior. It is well known as described in Japanese Patent Publication No.

(Problems to be solved by the invention) Although the evaporator of the refrigeration cycle of such a vehicle air conditioner is separated into a large number of refrigerant paths, the refrigerant flow distribution in all the refrigerant paths should be uniform. Difficult to do. Especially in the cooling system of a bath, it is common that air is taken in in a direction perpendicular to the plane of the evaporator, and the air enters the evaporator while changing its direction by approximately 90 °. It becomes non-uniform and the amount of heat transferred in the refrigerant pipe of the evaporator varies. Therefore, the degree of superheat of the refrigerant is controlled with reference to the refrigerant path having the worst heat transfer, and thus the degree of superheat is increased in the other refrigerant paths, and the efficiency of the entire evaporator is lowered. .

On the other hand, in a vehicle such as a bus, there is a problem that the cooling air that has passed through a duct in a part of the passenger compartment, for example, in the rear part, is less likely to spread, and the cooling effect of that part becomes insufficient.

SUMMARY OF THE INVENTION The main object of the present invention is to prevent such a decrease in heat exchange efficiency in an evaporator and to easily perform supplemental cooling of a portion in the vehicle compartment where cooling air is difficult to reach.

(Means for Solving the Problems) The present invention provides a compressor, a condenser, an expansion means, and a first evaporator and a second evaporator as a heat exchanger for cooling indoor air of a vehicle.
An air conditioner for a vehicle, comprising a refrigeration cycle in which a plurality of evaporators are sequentially connected in a closed circuit is provided in a casing, wherein the first evaporator is connected to a duct for sending air to the interior of the vehicle, and the second evaporation is provided. The heat exchanger is connected to an indoor heat exchanger provided inside the vehicle compartment away from the first evaporator in the casing via a heat exchange medium circuit having a pump.

In the vehicle air conditioner, the first evaporator is an evaporator that only evaporates the refrigerant, and the second evaporator is an evaporator that evaporates the remaining liquid refrigerant and superheats the refrigerant after evaporation. A means for detecting the degree of superheat of the refrigerant is provided on the outlet side of the second evaporator, and a control device for controlling the degree of superheat of the refrigerant on the outlet side of the second evaporator is provided by a detection signal from the detecting means. Can be

(Operation) With such a configuration, the degree of refrigerant superheat on the outlet side of the second evaporator is sensed by detecting the temperature or pressure of the refrigerant, and the expansion valve and the like are controlled accordingly, and the refrigerant in the first evaporator is controlled. The refrigeration cycle is controlled so that evaporation is performed and the refrigerant is overheated in the second evaporator. Further, the portion of the vehicle interior where the cooling air does not easily spread is supplemented by the medium sent from the second evaporator to the indoor heat exchanger installed therein by the heat exchange medium circuit.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 mainly shows a circuit of a refrigerator of a cooling device for a bath, which includes a compressor CP, a condenser CD, a receiver R,
An expansion valve EX1, a first evaporator EV1, and a second evaporator EV2 are sequentially provided, and these are connected so as to form a closed circuit. The first evaporator EV1 is connected to a duct that sucks air from the vehicle interior and sends it back into the vehicle interior, and return air from the vehicle interior sent by the blower 2 passes through the first evaporator EV1. It is cooled and discharged in the direction of the arrow.

The first evaporator EV1 is housed in the casing 3 shown in FIG. 2, and the cooled air is blown into the vehicle interior through the duct 4 from the air outlet 5 at the ceiling of the vehicle interior for cooling.
Further, the air in the vehicle compartment is returned to the casing 3 via a known air suction port and a return air duct (not shown). In addition, E shows a main engine for traveling.

In FIG. 2, reference numeral 6 denotes an indoor heat exchanger for cooling, which is provided at a place where the cooling effect tends to be insufficient, for example, at the rear part of the vehicle interior. A blower 7 is provided to send air through the indoor heat exchanger 6. The indoor heat exchanger 6 is the first
As shown in the figure, it is connected to the second evaporator EV2 via a cooling medium pipe 8. The water cooled by the second evaporator EV2 and other cooling medium are circulated in the pipe 8 in the direction of the arrow by the pump 9 to cool the air passing through the indoor heat exchanger 6. As a result, the rear part of the vehicle compartment is further cooled.

Most of the current buses are of the rear engine type, and the inside of the passenger compartment therefore tends to be warmer toward the rear. On the other hand, since the duct with an outlet running along the ceiling sends air from the front to the rear, the temperature of the blown air increases as it goes rearward (there is a difference of about 5 ° C in the experiment).

However, by providing the indoor heat exchanger 6 in the rear portion of the vehicle compartment as shown in FIG. 2, supplementary cooling is performed in the rear portion of the vehicle compartment, and the cooling effect in the vehicle compartment becomes uniform. The supplementary cooling by the indoor heat exchanger 6 is not limited to the rear portion of the passenger compartment, but the rear portion of the passenger compartment is effective in terms of temperature distribution and space. In this way, the installation of the indoor heat exchanger 6 at a place requiring supplementary cooling is
Since it can be performed without installing the cooling duct, the duct installation space is unnecessary, which is advantageous in terms of cost. The indoor heat exchanger 6 can be removed easily because the cooling medium pipe 8 can be left as it is. Further, if the cooling medium circulation pump 9 is capable of capacity control, it is possible to change the pump speed according to the cooling load and to exert the cooling capacity without waste.
Note that the cooling capacity can be adjusted by changing the rotation speed of the blower 7 instead of the pump 9, and the heat pump that pumps up heat in the indoor heat exchanger 6 and discards it to the second evaporator EV2 is the cooling medium pipe 8 Since it may be provided instead of, the control becomes easy.

As shown in FIG. 1, the second evaporator of the refrigeration cycle circuit
On the downstream side of EV2, there is a temperature sensing cylinder, that is, refrigerant superheat detection means 1
0 is provided, and the expansion valve EX1 is controlled by the superheat signal from this. As shown in the Mollier diagram of FIG. 3, the expansion valve EX1 is mainly composed of the second refrigerant.
The EV2 is controlled to overheat.

In this way, by performing control so that the refrigerant does not become overheated in each path of the first evaporator EV1, the distribution of the refrigerant in a large number of paths becomes relatively uniform, and the first evaporator EV1 Since the refrigerant temperature is the same from the front to the rear of the evaporator, the heat exchange efficiency of the evaporator is improved compared to the conventional one (second evaporator EV2
Is relatively small, so there is no space problem,
It is possible to improve the air distribution and the distribution to be good).

On the other hand, as described above, by providing the indoor heat exchanger 6 for supplementary cooling, the amount of heat transferred to the first evaporator EV1 can be reduced, so that the first evaporator can be downsized, and that much By reducing the air flow rate, the duct size can be reduced, the passenger compartment can be made wider, the visibility of passengers can be improved, or the air velocity in the duct can be reduced to reduce noise and save energy. .

FIG. 4 shows another embodiment of the present invention. In this embodiment, an inexpensive capillary tube EX2 is used in place of the expansion valve EX1 of FIG. 1, and a refrigerant pressure or temperature detector 10a or 10b is provided downstream of the second evaporator EV2 to detect this. The rotation speed of the pump 9 is controlled by the controller 11 which receives the detection value of the container.

As a result, the degree of superheat of the refrigerant entering the compressor CP can be controlled to be constant, and the control by the expansion means EX2 can be omitted.

FIG. 5 shows still another embodiment of the present invention. In this embodiment, a heating circuit is added to the first embodiment. That is, the heating heat exchanger H is installed adjacent to the first evaporator EV1, and the pipes 8g, 8c, 8d are provided to send the cooling water (warm water) from the traveling engine E to the heat exchanger H. Pipes 8e, 8b, 8f are provided to return the water sent from the heat exchanger H to the engine E. The pipe 8g has an opening / closing valve V1, the pipe 8d has an opening / closing valve V2, and the pipe 8e has an opening / closing valve V3. However, a switching valve V4 is provided at the boundary between the pipes 8b and 8f. In addition, 12 is the engine E
2 shows a radiator of cooling water of. During the heating period, hot water is sent from the engine E to the heat exchanger H for heating to warm the air and send it into the vehicle compartment through the duct.

In this embodiment, the heating medium hot water pipes 8b and 8c are used to form a cooling medium pipe. That is, the second evaporator EV
The pipe 8a from 2 is connected to the pipe 8b, and the pipe 8c is connected to the second evaporator EV2 via the pipe 8h. Now, when the switching valve V4 is switched so that the pipe 8b is connected to the pipe 8i, the pipes 8a, 8b, 8i, 8c, 8h
The cooling medium piping is configured by the above, and the indoor heat exchanger 6 supplements the cooling. In FIG. 5, DF indicates a defroster.

In this embodiment, cooling can be performed using the same pipe as in heating, and the indoor heat exchanger 6 also releases heat to the room during heating, so that the heating capacity is improved. Further, it is advantageous in terms of equipment since it is not necessary to provide a special cooling pipe.

[Effect of device]

In the present invention, the refrigeration cycle is provided with the first and second evaporators in series, the superheat degree of the refrigerant on the outlet side of the second evaporator is detected, and the detected value causes the evaporation of the refrigerant in the first evaporator. Since the refrigeration cycle is controlled so that the refrigerant is overheated in the second evaporator, the efficiency of the first evaporator is particularly improved. Also, in the present invention, the first unit connected in the air duct
Since the indoor heat exchanger is provided in the indoor part where the cooling effect is not sufficiently achieved only by the cooling by the evaporator and it is cooled by the second evaporator, it is possible to uniformly cool all the parts in the room. it can. And the indoor heat exchanger and the second
Since the evaporator is connected via the heat exchange medium circuit,
Since it is not necessary to install a cooling duct, it becomes easy to install the indoor heat exchanger at a remote place in the vehicle interior.

[Brief description of drawings]

FIG. 1 is a piping diagram of an embodiment of the present invention, FIG. 2 is an explanatory view of an air conditioner for a bath, FIG. 3 is a Mollier diagram of the refrigeration cycle shown in FIG. 1, and FIG. FIG. 5 is a piping diagram of another embodiment, and FIG. 5 is a piping diagram of still another embodiment of the present invention. CP …… compressor, CD …… condenser, EX1, EX2 …… expansion means, E
V1 ... First evaporator, EV2 ... Second evaporator, 2,7 ... Blower, 3 ... Casing, 4 ... Duct, 5 ... Blowout port,
6 ... Indoor heat exchanger, 8 ... Cooling medium piping, 9 ... Pump, 10,10a, 10b ... Superheat detection means, 8a, 8b, 8c ... Cooling medium piping, 8g, 8c, 8d, 8e , 8b, 8f …… Hot water piping for heating, E
...... Traveling engine, 11 …… Controller, 12 …… Radiator, H …… Heating heat exchanger.

Claims (2)

[Scope of utility model registration request] 1. A first evaporator and a second evaporator as a compressor, a condenser, an expansion means, and a heat exchanger for cooling indoor air of a vehicle.
In a vehicle air conditioner having a casing in which a refrigeration cycle in which evaporators are sequentially connected in a closed circuit is provided, the first evaporator is connected to a duct that sends air to the interior of the vehicle, and the second evaporator is An air conditioner for a vehicle, characterized in that the air conditioner is connected to an indoor heat exchanger provided inside the vehicle compartment away from the first evaporator in the casing via a heat exchange medium circuit having a pump. 2. The first evaporator is an evaporator that only evaporates the refrigerant, and the second evaporator is an evaporator that evaporates the remaining liquid refrigerant and superheats the refrigerant after evaporation. A means for detecting the degree of superheat of the refrigerant is provided on the outlet side of the evaporator, and a control device for controlling the degree of superheat of the refrigerant on the outlet side of the second evaporator is provided by a detection signal from the detecting means.
The vehicle air conditioner described.