JPH04288462A - Refregeration cycle - Google Patents

Abstract

PURPOSE:To reduce a delay in response of an expansion valve and to decrease a refrigerant passing sound generated when an air conditioner is started to operate. CONSTITUTION:A check valve 8 disposed to enable a shielding of a communication between a receiver 4 and an expansion valve 5 is placed between the receiver 4 and the expansion valve 5 in a refregeration cycle 1. This check valve 8 is operated in response to differential pressure between an upstream side (a side of the receiver 4) and a downstream side (a side of the expansion valve 5) of the check valve 8 and the valve is opened only when a pressure at the upstream side is higher than a pressure at the downstream side.

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 an air conditioner.

0002

[Prior Art] For example, in the refrigeration cycle of a vehicle air conditioner, an expansion valve is installed upstream of a refrigerant evaporator to rapidly expand liquid refrigerant introduced from a receiver into a low-temperature, low-pressure atomized refrigerant. It is provided. This expansion valve immediately responds to the vaporization state of the refrigerant within the refrigerant evaporator and controls the refrigerant flow rate so that the gas refrigerant at the outlet of the refrigerant evaporator always has a constant degree of superheat.

0003

Generally, when an air conditioner is started, the expansion valve is fully opened because the low pressure drops rapidly as the refrigerant compressor operates. At this time, if liquid refrigerant is not accumulated upstream of the expansion valve, gas refrigerant will flow through the expansion valve. As a result, the degree of superheat of the refrigerant evaporator does not decrease, and the expansion valve remains fully open.

After that, even if liquid refrigerant flows into the expansion valve,
It takes time for the superheat to reach from the expansion valve to the outlet of the refrigerant evaporator and reach the control range of the expansion valve. During this delay in response of the expansion valve, the expansion valve remains fully open and a large amount of refrigerant flows. As a result, there have been problems in that the refrigerant passing noise generated when the gas refrigerant passes through the expansion valve becomes louder, and the generation time becomes longer.

The present invention has been made based on the above-mentioned circumstances, and its object is to reduce the refrigerant passage noise by reducing the response delay of the expansion valve.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention includes a refrigerant compressor that compresses and discharges a sucked refrigerant, and a refrigerant compressor that is provided downstream of the refrigerant compressor. a refrigerant condenser that condenses and liquefies high-temperature, high-pressure gas-phase refrigerant discharged from the refrigerant condenser; an expansion valve that is provided downstream from the refrigerant condenser to depressurize and expand the supplied refrigerant; Interposed in the refrigerant passage leading to the valve,
The technical means includes an opening/closing means that opens the refrigerant passage when the refrigerant compressor is activated and closes the refrigerant passage when the refrigerant compressor stops operating.

[0007]

[Operation] In the refrigeration cycle of the present invention having the above configuration, the opening/closing means provided in the refrigerant passage leading from the refrigerant condenser to the expansion valve closes the refrigerant passage when the refrigerant compressor stops operating, thereby opening the expansion valve. Liquid refrigerant will be sealed upstream.

[0008] After that, when the refrigerant compressor is started, the expansion valve is fully opened due to the sudden drop in low pressure, but the opening/closing means opens the refrigerant passage as the refrigerant compressor starts.
The liquid refrigerant that has accumulated upstream of the expansion valve flows directly to the expansion valve. As a result, the response delay of the expansion valve when the refrigerant compressor is started is reduced, and the time during which the maximum flow rate of gas refrigerant flows is shortened.

[0009]

[Embodiment] Next, a refrigeration cycle of the present invention will be explained based on an embodiment shown in the drawings. Figure 1 shows a refrigeration cycle. The refrigeration cycle 1 is used, for example, in a vehicle air conditioner (hereinafter referred to as an air conditioner), and includes functional parts such as a refrigerant compressor 2, a refrigerant condenser 3, a receiver 4, an expansion valve 5, and a refrigerant evaporator 6. It has a well-known structure in which each of these functional parts is connected in an annular manner by a refrigerant pipe 7.

In the refrigeration cycle 1 of this embodiment, a refrigerant pipe 7a (refrigerant passage of the present invention) connecting the receiver 4 and the expansion valve 5 is provided with a refrigerant pipe capable of blocking communication between the receiver 4 and the expansion valve 5. A check valve 8 (opening/closing means of the present invention) is interposed. This check valve 8 is on the upstream side of the check valve 8 (receiver 4 side)
It operates based on the differential pressure between the valve and the downstream side (expansion valve 5 side), and opens only when the pressure on the upstream side is higher than the pressure on the downstream side.

[0011] Therefore, when the air conditioner is operating (refrigerant compressor 2
(during operation), as shown in FIG. 2(a), the check valve 8 is opened due to the flow of refrigerant, and the refrigeration cycle 1 is configured in the same way as usual. In addition, when the air conditioner stops operating, the flow of refrigerant stops and the pressure tries to become equal before and after the check valve 8 (upstream and downstream sides), so as shown in Figure 2 (
As shown in b), the check valve 8 closes to cut off communication between the receiver 4 and the expansion valve 5.

The expansion valve 5 immediately responds to the vaporization state of the refrigerant in the refrigerant evaporator 6, and controls the refrigerant flow rate so that the gas refrigerant at the outlet of the refrigerant evaporator 6 always has a constant degree of superheat. It is something. Therefore, in general, when the air conditioner is started, if liquid refrigerant is not accumulated in the receiver 4 or the refrigerant pipe 7, the gas refrigerant will flow and the degree of superheat will not decrease, and the expansion valve 5 will remain fully open. After that, even if the liquid refrigerant flows, it takes time until it reaches the outlet of the refrigerant evaporator 6 from the expansion valve 5, the degree of superheat decreases, and reaches the control range of the expansion valve 5.

Due to this delay in response of the expansion valve 5, the expansion valve 5
Since a large amount of gas refrigerant flows through the air conditioner when it is fully opened, the sound of the refrigerant passing through the air conditioner appears as a noise when starting the air conditioner.

Therefore, in this embodiment, when the operation of the air conditioner is stopped, the check valve 8 is closed, so that liquid refrigerant is sealed upstream of the expansion valve 5. Therefore, when the air conditioner is started, the liquid refrigerant sealed upstream of the expansion valve 5 flows, which reduces the response delay of the expansion valve 5.
The time during which the expansion valve 5 is fully opened and the maximum flow rate of gas refrigerant flows can be shortened.

[0015]

[Effects of the Invention] According to this embodiment, compared to the conventional refrigeration cycle, there is less drop in low pressure when starting the air conditioner (see Fig. 3), and the absolute value of the refrigerant passing sound can be lowered. The generation time is shortened (see Figure 4).
, it is possible to reduce the noise generated when starting the air conditioner.

In this embodiment, a check valve 8 is disposed between the receiver 4 and the expansion valve 5, but the check valve 8 is disposed between the refrigerant condenser 3 and the receiver 4.
It may be placed between. The check valve 8 may be mechanical or electrical as long as it is operated by differential pressure. Also,
Instead of the check valve 8, other opening/closing means such as a solenoid valve that operates based on an on/off signal of the refrigerant compressor 2 may be used.

[Brief explanation of the drawing]

FIG. 1 is an overall diagram of a refrigeration cycle.

FIG. 2 is an explanatory diagram of the operation of the check valve.

FIG. 3 is a graph showing fluctuations in low pressure.

FIG. 4 is a graph showing changes in refrigerant passing sound.

[Explanation of symbols]

1 Refrigeration cycle 2 Refrigerant compressor 3 Refrigerant condenser 5 Expansion valve 7a Refrigerant piping (refrigerant passage) 8 Check valve (opening/closing means)

Claims (1)

[Claims] Claim 1: a) a refrigerant compressor that compresses and discharges a sucked refrigerant, and b) a refrigerant compressor that is provided downstream of the refrigerant compressor and that compresses and discharges high-temperature, high-pressure gas phase refrigerant discharged from the refrigerant compressor. a refrigerant condenser that condenses and liquefies; c) an expansion valve that is provided downstream from the refrigerant condenser and depressurizes and expands the supplied refrigerant; and d) a refrigerant passage that is interposed in a refrigerant passage from the refrigerant condenser to the expansion valve. and opening/closing means for opening the refrigerant passage when the refrigerant compressor is activated and closing the refrigerant passage when the refrigerant compressor is stopped.