JPS61171606A - Freezing device for car air conditioning equipment - Google Patents

Abstract

PURPOSE:To enable the cooling capability and a decreasing rate of discharge temperature to be augmented by configurating a device in such a manner that a flow control valve, in which both the inner surface of a case and a piston are tapered with the piston which is forced against the small diameter side, is arranged between a receiver and an inlet port to a compressor with the small diameter side faced against the receiver side. CONSTITUTION:An inlet pressure Ps of a compressor 21 decreases gradually as an engine (22) speed increases allowing a discharge pressure Pd to increase. This causes the difference in pressure between the inlet pressure Pex of an injection piping 29 and a discharge pressure Ps of a discharge port 30 of a flow control valve 27 to increase in proportion to the engine speed. This allows a piston 35 to be displaced depending on the setting force of an adjust spring 37 of the control valve 27 so as to control the fluid flow. In this case, as both the piston 35 and the inner surface of a case 32 are tapered, the opening of the injection passage 38 is increased as the piston is displaced permitting the discharge pressure to be decreased. Thus, a decreasing rate of discharge temperature for a high engine speed range can be augmented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a car air conditioner refrigeration system used for cooling automobiles.

BACKGROUND OF THE INVENTION In recent years, automobiles have improved engine horsepower through turbochargers, DOHCs, etc., and automobiles have also appeared whose maximum permissible rotational speed is up to 9000 rpm, up from the conventional esoorp. Along with this, the engine sends I! through the belt! In car air conditioner refrigeration systems, which are characterized by the use of specially designed compressors, the rotational speed of the compressor is proportional to the engine rotational speed, so the discharge capacity of the compressor becomes excessive during high-speed rotation, causing problems in the refrigeration cycle.
The discharge pressure increases, the suction pressure decreases, and as a result, the discharge temperature tends to rise significantly, causing deterioration and damage to the rubber piping.
This causes harmful effects such as carbon precipitation in the refrigerating machine oil.

To solve this problem, the conventional method was to insert and connect an auxiliary device called an EPR (evaporator pressure regulator) between the evaporator and the compressor to draw liquid components into the compressor and lower the discharge temperature. .

5 and 6 illustrate a conventional car air conditioner refrigeration system. In FIG. 5, 1 is a compressor, which is driven by an engine 1a via a belt. 2 is a condenser which has a heat dissipation function, and the high temperature refrigerant gas becomes liquid refrigerant at the outlet. 3 is a receiver, which adjusts the amount of liquid refrigerant. Reference numeral 4 denotes an expansion valve, and the refrigerant whose pressure is reduced by the expansion IN valve 4 is vaporized by absorbing heat from the outside air in an evaporator 5. 6 is EP
R (evaporator pressure regulator) is an auxiliary device that keeps the refrigerant evaporation pressure in the evaporator constant.

The EPR 6 includes a control valve 7, a spring 8, and a case 11 that houses these and has an inlet 9 and an outlet 10 for refrigerant gas.

The operation of the car air conditioner refrigeration system configured as described above will be explained below.

When the rotational speed of the compressor 1 increases, the amount of refrigerant circulating within the cycle gradually increases, and the suction pressure of the compressor 1 decreases. Along with this, the pressure at the inlet 9 of the EPR decreases, but at this time, the control valve 7 moves in the direction of narrowing the passage 12 (to the left in Fig. 6) in balance with the spring 8 set to a certain force. and reduce the refrigerant flow rate. As a result, the evaporator 5 on the upstream side of the EPR 6
The pressure is kept at a predetermined constant value, and the evaporation temperature is kept constant. Due to this effect, the amount of refrigerant circulated in the evaporator 5 increases as the rotation speed increases, but since the temperature difference with the outside air does not change, sufficient heat exchange is not possible in the high speed rotation range, and the unevaporated portion of the liquid refrigerant increases. There will be more.

Therefore, in the high speed rotation range, the liquid refrigerant at the outlet 10 of the EPR 6 tends to back up and flows into the compressor 1, so that the liquid refrigerant evaporates within the cylinder of the compressor 1, and the discharge temperature of the compressor 1 decreases due to endothermic action. As a result, by inserting EPR6, a car air conditioner refrigeration system was constructed that did not cause a sudden temperature rise even in the high-speed rotation range (Refrigerating and Air Conditioning Handbook (Basic Edition) p. 491 to p. 49)
3).

□□8. 1 However, in the above configuration, EPR6
Since the operation of the control valve 7 uses the pressure difference between the front and rear,
Even in the low-speed rotation range, there was a problem that passage resistance existed and the cooling capacity deteriorated due to pressure loss. Furthermore, EPR6
The rate of decrease in the discharge temperature caused by this method was approximately 10% at most, and a further decrease rate could not be expected.

The present invention solves the above-mentioned problems, and aims to provide a car air conditioner refrigeration 5A@ that has no passage loss in the low speed rotation range and achieves a discharge temperature reduction rate of 20% or more in the high speed rotation range. do.

Means for Solving the Problems In order to solve the above problems, the car air conditioner refrigeration system of the present invention includes a compressor driven by an engine, a condenser for dissipating heat, a receiver for storing liquid refrigerant, an expansion valve, In a car air conditioner refrigeration system configured by sequentially connecting evaporators that perform an endothermic action with piping, a flow I1 is created between the receiver or the piping before and after the receiver and the compressor or the 5 piping on the inlet side of the compressor.
A case having an inner circumferential surface whose diameter becomes larger toward the compressor, and a piston housed in the case and having a tapered outer circumferential surface whose diameter becomes larger toward the compressor. and an adjustment spring that urges the piston toward the receiver and presses it toward the valve seat on the inner surface of the case.

Effect of the present invention With the above-described configuration, when the pressure difference between the inlet of the injection pipe and the outlet of the flow rate control valve is equal to or less than the set pressure of the adjustment spring (in a low speed rotation range), the control valve is in a closed state, and the control valve is normally closed. This is a refrigeration system with no flow path loss, and when the pressure difference becomes larger than the calibrated value in the high-speed rotation range, the control valve opens the injection passage according to the pressure difference and injects liquid refrigerant into the compressor. By this,
A significant discharge temperature reduction rate can be achieved.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

Fig. 1 is a sectional view of the flow control valve used in the car air conditioner refrigeration system of the present invention, Fig. 2 is a block diagram of the car air conditioner refrigeration @ Kasumi, and Fig. 3 is a diagram showing changes in pressure and injection ■ with respect to rotation speed. , FIG. 4 is a diagram showing changes in discharge temperature with respect to rotation speed.

21 is a compressor, 22 is an engine that drives the compressor 21, and 23 is a condenser having a heat dissipation function, and the gaseous high-temperature refrigerant becomes liquid refrigerant at the outlet of the condenser. 24 is a receiver for adjusting the liquid-cooled soot layer; 25 is an expansion valve; the refrigerant whose pressure is reduced by the valve 25 is vaporized by taking heat from the outside air in an evaporator 26; Reference numeral 27 designates a flow control valve, and an inlet 28 of the flow control valve 27 is connected to the receiver 24 via an injection pipe 29, and an outlet 30 is connected to the inlet side of the compressor 21.

31 is a cylindrical case of the flow control valve 270;
The inner peripheral surface 32 of 1 is the outlet 3 connected to the compressor 21
The valve seat 34 is formed in a tapered shape with a larger diameter toward the 0 side, and a valve seat 34 communicating with the inlet 28 is formed on a bottom wall 33 provided on the inlet 28 side of the case 31 . 35 is a piston housed in the case 31, and the tapered outer circumferential surface 3G of the piston 35 is as follows:
The diameter becomes larger toward the compressor 21 side. 37 valves the piston 35! ! 34 with an adjustment spring that presses and biases the
The spring 31 causes the top wall 38 of the piston 35 to press against the valve seat 34.
The inlet 2B can be closed by coming into contact with it.

The operation of the flow control valve of the car air conditioner refrigeration giW1 configured as described above will be explained.

Assuming that the compressor 21 is driven by the engine 22 and the rotation speed gradually increases, the compressor 2
1, the suction side pressure ps gradually decreases, while the discharge side pressure Pd also gradually increases, so the injection arrangement! ! 2
The pressure difference between the inlet pressure pex of 9 and the outlet 30 pressure ps of the 1111 n valve 27 increases in proportion to the increase in rotational speed. Therefore, by utilizing this phenomenon and setting the adjustment spring 31 of the flow rate control valve 27 to a spring force FO corresponding to a certain pressure difference, the injection starting point is set. For example, in FIG. 3, the piston 35 starts moving at 3000 rpm or more, and the piston 35 starts moving by one force. Yo4. Wow, 12. a. □□□1
I'm coming. At this time, 429 formed between the tapered inner peripheral surface 32 of the case and the tapered outer peripheral surface 36 of the piston
19212 Since the opening degree of the passage 38 gradually increases in proportion to the amount of movement of the piston, the injection l G
i increases in proportion to the pressure difference. As a result, as shown in FIG. 4, the discharge temperature of the compressor 21 increases in proportion to the rotational speed in a general refrigeration system, and reaches a temperature of 5000 rpm.
In the refrigeration system of the present invention, the temperature at 5000 rpm was reduced to 140°C (12.5%) by injecting liquid refrigerant in proportion to the pressure difference.
, the discharge temperature can be reduced to 148° C. (20%) at 60 GO rpm.

As described above, according to this embodiment, in the low speed range, the receiver 2
When the pressure difference between the compressor 4 and the inlet of the compressor 21 is small, the refrigeration system operates as a normal refrigeration system without flow path loss, and in a relatively high-speed rotation range where the pressure difference exceeds a certain set value,
Since liquid refrigerant is injected into the compressor 21 according to the pressure difference, a high discharge temperature reduction rate can be achieved in the high speed rotation range.

In this embodiment, the inlet of the injection pipe 29 is connected to the receiver 24, but the connection pipe between the condenser 21 and the receiver 24, or the receiver 24 and the expansion valve 2 is connected to the receiver 24.
Further, although the outlet 30 of the flow rate control valve 27 is the inlet of the compressor 21, it may be a pipe connecting the compressor 21 and the evaporator 23, or a compression stroke part of the compressor 21.

Effects of the Invention As described above, the car air conditioner refrigeration system of the present invention forms a normal refrigeration system with no loss when the pressure difference between the inlet and outlet of the flow control valve is below a certain set value, and when the pressure difference exceeds the set value, the pressure difference is reduced. By injecting a liquid refrigerant proportional to can be assembled.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a cross-sectional view of a flow control valve used in a car air conditioner refrigeration system, FIG. 2 is a block diagram of the car air conditioner refrigeration system, and FIG. Figure 3 shows changes in pressure and injection amount with respect to rotation speed in a car air conditioner refrigeration system, Figure 4 shows changes in compressor discharge concentration with respect to rotation speed, and Figures 5 and 6 show conventional examples. , 5th @ is a configuration diagram of a car air conditioner freezing bag and a sectional view of the AEPR (evaporator pressure regulator). 21...Compressor,
22... Engine, 23-... Capacitor, 24...
・Receiver, 25... Expansion valve, 26... Evaporator, 27... Flow rate control valve, 31... Case, 32...
...Tapered inner circumferential surface, 34...Valve seat, 35...Piston, 36...Tapered outer circumferential surface, 37...Adjustment spring agent Yoshihiro Morimoto21---F;70L・S' 32-1-no-wa (-11--way b

Claims (1)

[Claims] 1. In a car air conditioner refrigeration system that is configured by sequentially connecting a compressor driven by an engine, a condenser that radiates heat, a receiver that stores liquid refrigerant, an expansion valve, and an evaporator that absorbs heat through piping, the receiver or its A case in which a flow control valve is interposed between the front and rear piping and the compressor or the inlet side piping of the compressor, and the flow control valve has a tapered inner peripheral surface whose diameter increases toward the compressor; The piston is housed in the case and includes a piston having a tapered outer circumferential surface whose diameter increases toward the compressor, and an adjustment spring that biases the piston toward the receiver and presses it toward the valve seat on the inner surface of the case. Car air conditioner refrigeration system.