JP3257201B2 - Refrigeration cycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle for a vehicle in which the supply of refrigerant to a sub-evaporator provided in parallel with a main evaporator is regulated by an electromagnetic valve.

[0002]

2. Description of the Related Art Conventionally, this type of refrigeration cycle is disclosed, for example, in Japanese Patent Publication No.
As shown in Japanese Patent No. 61, it is used for an air conditioner for a vehicle with a refrigerator, a dual (twin) air conditioner for a vehicle, and the like. In this refrigeration cycle, for example, as shown in FIG. 5, a main refrigerant circuit 13 connecting an expansion valve 11 and a main evaporator 12 is connected to a sub refrigerant circuit 17 connecting an electromagnetic valve 14, an expansion valve 15, and a sub evaporator 16 to each other. Are connected in parallel, the high-temperature gas refrigerant discharged from the compressor 18 is radiated and liquefied by the condenser 19, and the liquid refrigerant flows to the main refrigerant circuit 13 via the receiver 20 and is supplied to the main evaporator 12, and When the solenoid valve 14 of the circuit 17 is opened, the liquid refrigerant is also supplied to the sub-evaporator 16 via the expansion valve 15. Thereafter, when the solenoid valve 14 is closed, the supply of the refrigerant to the sub-evaporator 16 is stopped, and the refrigerant is supplied only to the main evaporator 12.

[0003]

In the above-mentioned conventional structure, when the solenoid valve 14 of the sub-refrigerant circuit 17 is closed, the flow of the high-pressure liquid refrigerant having low compressibility is suddenly shut off by the solenoid valve 14. As shown in FIG. 3A, a sudden pressure fluctuation occurs on the upstream side of the solenoid valve 14, and a water hammer phenomenon is caused. Similarly, when the solenoid valve 14 is opened, a large amount of high-pressure refrigerant is suddenly moved toward the expansion valve 15, causing a sudden pressure fluctuation as shown in FIG.
The water hammer phenomenon is caused. For this reason, each time the solenoid valve 14 is opened / closed, FIGS.
As shown in (b), the water hammer phenomenon causes the solenoid valve 14 and the refrigerant pipe around it to vibrate greatly, generating a loud impact noise, which is extremely disadvantageous. When the solenoid valve is opened, a large amount of liquid refrigerant rapidly evaporates and expands in the process of passing through the solenoid valve 14 in a vigorous manner. This has also caused the noise to increase with the water hammer phenomenon.

The present invention has been made in view of such circumstances, and an object of the present invention is to reduce the impact sound of the water hammer phenomenon when opening and closing a solenoid valve, and to reduce the impact noise when the solenoid valve is opened. An object of the present invention is to provide a refrigeration cycle for a vehicle that can also reduce refrigerant passage noise.

[0005]

In order to achieve the above object, a refrigeration cycle for a vehicle according to the present invention is provided in a main refrigerant circuit in which refrigerant flows into a main evaporator via a temperature-type expansion valve. On the other hand, a sub-refrigerant circuit in which the refrigerant flows into the sub-evaporator via the solenoid valve is connected in parallel, and the main evaporator of the main refrigerant circuit is connected.
Open / close the solenoid valve during the period when refrigerant is supplied to the generator
By doing so, the refrigerant is supplied to the sub-evaporator of the sub-refrigerant circuit.
In those that supplied, the the sub refrigerant circuit, the positioned upstream of the secondary evaporator capillary tube provided, and with the provided magnet valve in the refrigerant flow path between the capillary tube and the auxiliary evaporator Things.

[0006]

The refrigerant supply to the main evaporator in the main refrigerant circuit is superheated by a temperature type expansion valve. On the other hand, the supply of refrigerant to the sub-evaporator in the sub-refrigerant circuit is mainly
This is started by opening the solenoid valve during the period when the refrigerant is being supplied to the evaporator, but in the conventional configuration, when opening the solenoid valve, a large amount of high-pressure refrigerant is suddenly moved toward the expansion valve. Then, as shown in FIG. 4A, a rapid pressure fluctuation occurs, and a water hammer phenomenon is caused. Furthermore, when the solenoid valve is opened, a large amount of liquid refrigerant rapidly evaporates and expands in the process of vigorously passing through the solenoid valve 14, thereby generating a high-level refrigerant passing noise called "shoe". .

On the other hand, according to the present invention, when the electromagnetic valve is opened, the liquid refrigerant is supplied to the sub-evaporator through the electromagnetic valve while being reduced in pressure in the capillary tube by the pipe frictional resistance. At this time, the flow rate of the refrigerant passing through the solenoid valve is reduced to a small flow rate by a pipe friction resistance in a capillary tube provided on the upstream side of the solenoid valve, so that the flow of the refrigerant does not become a large momentum, and a water hammer phenomenon occurs. Buffered. Moreover, the amount of refrigerant passing through the solenoid valve is limited,
Almost no refrigerant passing noise that has conventionally occurred is generated.

Further, while the solenoid valve is open, the liquid refrigerant flowing through the capillary tube and flowing to the solenoid valve is partially evaporated during the passage through the capillary tube. It becomes a gas-liquid two-phase state. Therefore, when the solenoid valve is closed and the supply of the refrigerant to the sub-evaporator is stopped, the refrigerant vapor present in the refrigerant flow path between the capillary tube and the electromagnetic valve causes pressure fluctuation when the flow of the refrigerant is shut off. And suppresses the water hammer phenomenon.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
One embodiment applied to an air conditioner will be described with reference to FIGS. As shown in FIG. 1, a condenser 22 and a receiver 23 are connected in series to a discharge port 21a side of a compressor 21, and a main evaporator 24 for a front cooler is provided between the receiver 23 and a suction port 21b of the compressor 21. A main refrigerant circuit 25 and a sub-refrigerant circuit 27 having a sub-evaporator 26 for a rear cooler are connected in parallel. The main refrigerant circuit 25 includes a main evaporator 24.
An expansion valve 28 is provided on the upstream side. The degree of opening of the expansion valve 28 is automatically adjusted by a temperature-sensitive cylinder 29 that detects the temperature of the outlet side of the main evaporator 24 so that an appropriate amount of refrigerant is supplied to the main evaporator 24 in accordance with a change in cooling load. (Super heat control).

On the other hand, in the sub-refrigerant circuit 27, a capillary tube 30 is provided on the upstream side of the sub-evaporator 26, and a normally closed type refrigerant passage 27a is provided between the capillary tube 30 and the sub-evaporator 26. An electromagnetic valve 31 is provided. ON / OFF (open / close) of the solenoid valve 31 is controlled by the control amplifier 32. The control amplifier 32 is connected to a temperature sensor 33 such as a thermistor for detecting the temperature of the wind blown from the sub-evaporator 26 (hereinafter, referred to as “rear blow temperature”), and a rear cooler switch 34.

An electromagnetic clutch 35 is connected to the rotating shaft of the compressor 21, and the rotational force of an engine (not shown) is transmitted through the electromagnetic clutch 35 to the compressor 21.
Is transmitted to ON / OFF of the electromagnetic clutch 35
It is switched by turning on / off the main cooler switch 36. Even when the main cooler switch 36 is on and the rear cooler switch 34 is off, power is not supplied from the battery 37 to the control amplifier 32 and the solenoid valve 31 of the sub-refrigerant circuit 27 is turned off (closed). Maintaining, only the front cooler is operated.

In the operation using only the front cooler, the refrigerant discharged from the discharge port 21a of the compressor 21
The refrigerant circulates through a path from the condenser 22 → the receiver 23 → the main refrigerant circuit 25 (the expansion valve 28 → the main evaporator 24) → the suction port 21 b of the compressor 21. That is, in the operation of only the front cooler, the solenoid valve 31 is turned off (closed),
No refrigerant is supplied to the sub-evaporator 26, and all the refrigerant is supplied to the main evaporator 24.

Thereafter, when the rear cooler switch 34 is turned on, power is supplied from the battery 37 to the control amplifier 32, the control amplifier 32 is operated, and the solenoid valve 31 is turned on (open). Thereby, the liquid refrigerant flowing out of the receiver 23 is divided into the main refrigerant circuit 25 and the sub-refrigerant circuit 27, and the normal operation in which the refrigerant is supplied to both the main evaporator 24 and the sub-evaporator 26 is performed. During this normal operation, the control amplifier 32 switches on / off (open / close) the solenoid valve 31 in accordance with the rear outlet temperature detected by the temperature sensor 33 as shown in FIG. Control to keep it near. That is, the lower limit temperature and the upper limit temperature are set on the basis of the target temperature, and after the operation is started, the solenoid valve 3 is operated until the rear outlet temperature decreases to the lower limit temperature.
1 is opened to supply the refrigerant to the sub-evaporator 26, and when the rear outlet temperature reaches the lower limit temperature, the solenoid valve 31 is closed to stop the supply of the refrigerant to the sub-evaporator 26. Thereafter, the solenoid valve 31 is maintained in a closed state until the rear blowout temperature rises to the upper limit temperature. When the rear blowout temperature reaches the upper limit temperature, the solenoid valve 31 is opened and the sub evaporator 2 is opened.
The supply of the refrigerant to the refrigerant 6 is restarted, and thereafter, the above-described operation is repeated to maintain the rear blow-out temperature near the target temperature.

When the rear cooler switch 34 is turned off during normal operation and the operation is switched to the operation of only the front cooler, or when the rear blowout temperature reaches the lower limit temperature during normal operation, the solenoid valve 31 is used. Is switched from on (open) to off (closed), and the supply of the refrigerant to the sub-evaporator 26 is shut off. At this time, in the case of the conventional configuration (see FIG. 5), the flow of the high-pressure liquid refrigerant having low compressibility is rapidly shut off by the solenoid valve 14, so that the upstream side of the solenoid valve 14 as shown in FIG. , A sudden pressure fluctuation occurs, causing a water hammer phenomenon, and the water hammer phenomenon causes the solenoid valve 14 and the refrigerant pipe around it to vibrate greatly as shown in FIG. Was.

On the other hand, in the present embodiment, a capillary tube 30 is provided upstream of the sub-evaporator 26, and a solenoid valve 31 is provided in a refrigerant flow path 27a between the capillary tube 30 and the sub-evaporator 26. Therefore, the liquid refrigerant passes through the capillary tube 30 and then passes through the solenoid valve 31. At this time, during the passage of the liquid refrigerant through the capillary tube 30, a part of the liquid refrigerant evaporates, so that the refrigerant flowing to the inlet of the solenoid valve 31 is in a gas-liquid two-phase state. Therefore, when the electromagnetic valve 31 is closed and the supply of the refrigerant to the sub-evaporator 26 is stopped, the refrigerant vapor present in the refrigerant flow path 27a between the capillary tube 30 and the electromagnetic valve 31 blocks the flow of the refrigerant. As shown in FIG. 3A, the pressure fluctuation when the solenoid valve 31 is closed is suppressed, and the water hammer phenomenon is reduced. As a result, as shown in FIG. 3B, the vibration when the solenoid valve 31 is closed becomes extremely small, and the impact sound becomes much smaller than in the prior art.

In addition, from the operation of only the front cooler,
When the rear cooler switch 34 is turned on to switch to the normal operation, or when the rear blowout temperature reaches the upper limit temperature during the normal operation, the solenoid valve 31 is switched from off (closed) to on (open). Then, the supply of the refrigerant to the sub-evaporator 26 is started. At this time, in the conventional configuration (see FIG. 5), when the solenoid valve 14 is opened,
By rapidly moving a large amount of high-pressure refrigerant toward the expansion valve 15, a sudden pressure fluctuation occurs as shown in FIG.
The water hammer phenomenon is caused, and as shown in FIG.
4 and its surrounding refrigerant pipes vibrated greatly, generating loud impact noise. In addition, when the solenoid valve 14 is opened, a large amount of liquid refrigerant passes through the solenoid valve 14 in a vigorous manner and evaporates and expands abruptly, thereby generating a high-level refrigerant passing noise called “shoe”. Was.

On the other hand, in this embodiment, the liquid refrigerant is supplied to the sub-evaporator 26 through the electromagnetic valve 31 while being reduced in pressure in the capillary tube 30 by the pipe frictional resistance. Is reduced to a small flow rate by the pipe frictional resistance in the capillary tube 30 provided on the upstream side of the solenoid valve 31 and the flow of the refrigerant does not become a large momentum, and is shown in FIG. Thus, the pressure fluctuation when the electromagnetic valve 31 is opened is suppressed, and the water hammer phenomenon is reduced. As a result, FIG.
As shown in (b), the vibration when the solenoid valve 31 is opened is extremely small, and the impact noise is significantly reduced. In addition, since the amount of the refrigerant passing through the solenoid valve 31 is limited, almost no refrigerant passing noise is generated.

In this embodiment, only one sub-evaporator 26 is used as a refrigerating cycle. However, two or more sub-evaporators are provided in parallel, and at least one sub-evaporator of the present invention is used for at least one sub-evaporator. The configuration of the refrigerant circuit may be applied.

In addition, the present invention is not limited to a dual (twin) air conditioner for a vehicle , and can be applied to, for example, an air conditioner for a vehicle with a refrigerator, and a refrigeration cycle for a vehicle provided with a plurality of evaporators in parallel. Various modifications can be made without departing from the scope of the invention, for example, the invention can be widely applied to an apparatus in which is incorporated.

[0020]

As is apparent from the above description, according to the present invention, the capillary tube is provided upstream of the sub-evaporator, and the solenoid valve is provided in the refrigerant flow path between the capillary tube and the sub-evaporator. With the configuration, the depressurizing action of the capillary tube can reduce the impact noise of the water hammer phenomenon when opening and closing the solenoid valve, and also reduce the refrigerant passage noise when the solenoid valve is opened. , Can meet the demand for noise reduction.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a refrigeration cycle showing one embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a rear outlet temperature and opening / closing of a solenoid valve during normal operation.

FIG. 3 is a diagram showing a change over time in pressure fluctuation and vibration acceleration when a solenoid valve is closed.

FIG. 4 is a diagram showing a change over time in pressure fluctuation and vibration acceleration when the solenoid valve is opened.

FIG. 5 is a configuration diagram of a conventional refrigeration cycle.

[Explanation of symbols]

21 compressor, 22 condenser, 23 receiver, 24 main evaporator, 25 main refrigerant circuit, 26
Sub-evaporator, 27 ... Sub-refrigerant circuit, 27a ... Refrigerant flow path, 28 ... Expansion valve, 29 ... Temperature sensing cylinder, 30 ... Capillary tube, 31 ... Electromagnetic valve, 32 ... Control amplifier, 33 ... Temperature sensor, 34 ... Rear cooler Switch, 36: Main cooler switch.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 1/00-7/00 B60H 1/32 621

Claims (1)

(57) [Claims] Respect 1. A main refrigerant circuit which the refrigerant flows into the main evaporator via a thermostatic expansion valve, the refrigerant through the solenoid valve
The sub-refrigerant circuit flowing into the sub-evaporator is connected in parallel, and the refrigerant is supplied to the main evaporator of the main refrigerant circuit.
Opening and closing the solenoid valve during the period of
In a refrigeration cycle for a vehicle that supplies a refrigerant to a sub-evaporator of a circuit, a capillary tube is provided in the sub-refrigerant circuit at an upstream side of the sub-evaporator, and a refrigerant flow between the capillary tube and the sub-evaporator is provided. A refrigeration cycle for a vehicle , wherein the electromagnetic valve is provided on a road.