JPS6229779A - Compressor for vehicle air conditioner - Google Patents

Abstract

PURPOSE:To improve a driving feeling of the driver, by controlling the proportion of an opening and closing time of opening and closing valves, provided in suction sides of a compressor, so that the delivery amount of a refrigerant of the compressor can be controlled with an electromagnetic clutch left as being turned on. CONSTITUTION:An air conditioner provides opening and closing valves 22A, 22B, consisting of two-port and two-position solenoid selector valves, in suction side flow lines 14 of a compressor 20 driven by an engine through an electromagnetic clutch. While a controller of said compressor 20 outputs a control signal which controls the proportion of a time for opening and closing the opening and closing valves 22A, 22B during a unit time on the basis of various signals of car room temperature, engine speed, etc. And the air conditioner controls the opening and closing valves 22A, 22B to be opened and closed by said control signal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a compressor for a vehicle air conditioner that can control the amount of refrigerant discharged while continuing compression operation.

(Prior Art) As a compressor for a vehicle air conditioner, for example, a vane type rotary compressor (hereinafter simply referred to as a compressor) as shown in FIG. 3.4 is known. In these figures, reference numeral 1 indicates a compression mechanism part housed in a housing (not shown) of a compressor, and this compression mechanism part l has a cam ring 2 and a rotor 3. As shown in FIG. 3, the cam ring 2 is made of a cylindrical body having a substantially elliptical cross section, and its inner circumferential surface is composed of a small interior 2A and a large interior 2B. The openings at both ends of the cam ring 2 are sealed by a front plate 4 and a rear plate 5, and the rotor 3 is sealed between these two plates 4.
5 through bearings 6A and 6B, and is rotatably supported within the cam ring 2, particularly within the small interior 2A. As shown in detail in FIG. 3, the rotor 3 has four slits 8 formed in its axial direction, and each slit 8 is arranged at equal intervals (90 degrees) in the circumferential direction of the rotor 3. Furthermore, each slit 8 extends substantially in the radial direction (radial direction) in the cross section in the direction perpendicular to the axis. In these slits 8, rectangular plate-like vanes 9A to 9D are slidably housed, and when the rotor 3 rotates, each tip of the vanes 9A to 9D is compressed by centrifugal force and vane back pressure. comes into sliding contact with the inner peripheral surface of the cam ring 2. Working chambers 10A and IOB are defined by the cam ring 2, rotor 3, and both plates 4.5, respectively, and each working chamber 10A, 10B is expanded or contracted by vanes 9''A to 9D, and acts as a suction chamber or a compression chamber. Further, on the inner circumferential surface of the cam ring 2, a pair of suction ports 11A, IIB and a discharge port 12A, which are separated by approximately 180 degrees in the circumferential direction and communicate with a refrigerant suction port (not shown) and a discharge port (not shown), are provided. 1
2B are open, respectively, and the suction ports 11A and II
The low-temperature, low-pressure refrigerant sucked into the working chamber 10A and IOB from B is compressed in the working chamber 10A and IOB by the rotation of the rotor 3, becomes high temperature and high pressure, and the discharge valve 7 opens at a predetermined pressure.
It is discharged from discharge ports L2A and 12/B provided with ports A and 7B through discharge ports. The rotor 3 is driven and stopped by receiving and cutting off the driving force transmitted from the engine via a drive belt (not shown) by the ON-OFF operation of the electromagnetic clutch 13 (see FIG. 5). The high-temperature, high-pressure refrigerant discharged from the discharge port of the compressor C is sent to the condenser 15 through the piping 14 of the refrigeration cycle as shown in FIG. 5, in which the compressor C is incorporated. The condenser 15 cools the fed refrigerant to a condensing temperature and reduces it to a medium-temperature, medium-pressure liquid.

This cooling is performed by a cooling fan attached to the front of the radiator or by air cooling depending on the vehicle speed. The refrigerant reduced to liquid is sent to the liquid tank 16 and stored there.Next, this liquid refrigerant is sent from the liquid tank 16 to the expansion valve 17, where it is rapidly expanded and becomes a low-temperature, low-pressure mist. , are sent to the evaporator 18. Then, in this evaporator 18, the cooling fan evaporates and turns into a gas while removing the heat of vaporization from the surroundings. At this time, the cooled air is sent into the interior of the vehicle as cold air by a blower, thereby cooling the interior of the vehicle. The evaporated refrigerant is then sent to the compressor C again and compressed.

(Problem to be Solved by the Invention) However, in general, the compressor of a vehicle air conditioner needs to ensure cooling power for the evaporator 18 even when the engine is rotating at low speed (so-called idling) when the vehicle is stopped. Increase its capacity.

For this reason, when the vehicle is driven at high speed, the compression capacity becomes excessive and the interior of the vehicle becomes too cold.
Repeat N-OFF frequently to turn compressor C to full capacity (10
They had to run it at 0% capacity or shut it down and adjust the room temperature. However, during high-speed operation, the electromagnetic clutch 13 is frequently turned ON and OFF.
In this case, the compression mechanism of the compressor is suddenly connected to high-speed operation from a stopped state, which not only causes a large shock, but also causes a loud operating sound during 0N-OFF, which significantly affects the driving feeling of the driver. I was making it worse. Further, since the electromagnetic clutch 13 is frequently turned ON and OFF, the friction surfaces of the electromagnetic clutch 13 are severely worn out, and the service life is significantly shortened, which is uneconomical.

Therefore, in order to solve this problem, a method has been proposed in which a constriction part such as an orifice is provided in the suction port of the compressor and the suction ports IIA and 11B to reduce the amount of refrigerant sucked.

However, if a constriction is provided at the inlet to the working chambers 10A, 10B to reduce the amount of refrigerant sucked in, the discharge amount (weight) will decrease, but the refrigerant will pass through the constrictor during suction and will be lower than the normal suction pressure. The refrigerant further reduced in pressure is discharged to the discharge port 12A,
In order to discharge it from 12B, it is necessary to compress it to the set pressure at which the discharge valves 7A and 7B open, so the compression ratio becomes extremely large. Therefore, the temperature inside the working chamber 10A and IOB becomes abnormally high, causing damage to the compressor, and the above-mentioned problems could not be solved.

(Means and effects for solving the problems) This invention was made by focusing on such conventional problems.
An on-off valve is provided in the suction side flow path that supplies refrigerant to the working chamber of the compressor, and by controlling the ratio of the opening/closing time of the on-off valve in one operating cycle time of the compressor, the electromagnetic clutch can be kept on. In other words, the refrigerant discharge amount can be controlled while the compressor is operating.
This solves the above problems.

(Example) Hereinafter, this invention will be explained based on examples.

FIG. 1 shows a refrigeration cycle incorporating an embodiment of the compressor according to the present invention, in which 14 is piping, 15 is a condenser, 16 is a liquid tank, 17 is an expansion valve, 18 is an evaporator, and 20 is a This compressor according to the present invention has the same structure and operation of the compression mechanism as the compressor C described above.

Two-point/two-position electromagnetic switching valves (hereinafter simply referred to as switching valves) 22A and 22B as on-off valves are attached to the suction ports communicating with the working chambers 10A and 10B of the compressor 20. Note that the switching valves 22A and 22B are connected to piping 14 that connects each suction port of the compressor 20 and the outlet of the evaporator 18.
It may be provided in the middle. And this switching valve 22A, 2
2B are switched simultaneously or selectively by electrical signals issued from a control device built in a computer (not shown), so that they are fully open or fully closed, respectively.

Next, the effect will be explained.

The refrigerant sucked into the working chamber 10A and IOB from the pipe 14 through the suction port and suction ports LIA and IIB is compressed by the rotation of the rotor 3, and after passing through the discharge ports 12A and 12B, the discharge valves 7A and 7B, and the discharge port. , are sent to the condenser 15 via the pipe 14. Here, when the control device detects via the sensor that various control conditions such as the temperature inside the vehicle cabin and the engine rotation speed have reached the set values stored in advance in the storage means of the control device, the control device A control signal is issued from the switching valves 22A and 22B. This control signal is a signal for controlling the proportion of time during which the switching valves 22A and 22B are opened and closed during one operating cycle time (unit time) of the compressor 20, that is, a duty ratio control signal. Then, by this control signal, the switching valves 22A, 2
2B is 1/2 of one operating cycle time of the compressor 20, for example, as shown in FIG. 2 (al, mountain) and (C).
．． Each working chamber 10A is opened and closed for 3/4 or 1/4 of the time and closed for the rest of the time.
, the amount of refrigerant supplied to the IOB can be controlled to 50%, 75%, and 25% of when the switching valves 22A and 22B are fully open, thereby controlling the amount of refrigerant discharged. Therefore, the switching valve 2
By fully closing one of the switching valves 2A and 22B and changing the duty ratio of the other, the overall discharge amount of the compressor 20 can be controlled from 0 to 50%. By fully opening one of the compressors and changing the duty ratio of the other, it is possible to control the overall discharge amount of the compressor 20 to 50 to 100%. Moreover, since the switching valves 22A and 22B are either fully open or fully closed, the compression ratio of the refrigerant when fully open is the same as that in the conventional compressor C that is not provided with a throttle. , the temperature rise in the working chamber is also the same as before. Furthermore, since the compression ratio when the valve is fully closed is O, the temperature rise in the working chamber is low. Therefore, the overall temperature rise in the working chamber is lower than in the past even if the refrigerant suction amount (discharge amount) decreases.

Furthermore, since the electromagnetic clutch 13 can remain ON or connected regardless of the opening/closing control of the switching valves 22A and 22B,
0N-OFF that worsens the driver's driving feeling
There is no shock or noise during operation, and wear on the friction surface of the electromagnetic clutch 13 is significantly reduced compared to conventional clutches.

In the above embodiment, a vane type rotary compressor having a pair of working chambers has been described, but the present invention can also be applied to a vane type rotary compressor having a single working chamber, a reciprocating compressor, etc. Needless to say.

(Effects of the Invention) As described above, according to the present invention, an on-off valve is provided in the suction side flow path for supplying refrigerant to the working chamber of the compressor of a vehicle air conditioner, and one operating cycle time of the compressor is reduced. By controlling the ratio of opening/closing time of the on-off valve, the intake amount of refrigerant can be controlled, and thereby the discharge amount can be controlled. As a result, it is possible to obtain a refrigerant discharge amount that corresponds to the required cooling capacity regardless of the engine speed, making it possible to reduce temperature changes in the cold air blown out from the evaporator and achieve a comfortable cooling effect. In addition, unlike conventional compressors, the electromagnetic clutch that transmits the driving force from the engine to the compressor is repeatedly turned off and on depending on the temperature inside the vehicle and the engine speed. Since it is not necessary and can be left on at all times while driving the vehicle, it is 0N.
- There is no shock or operating noise when the vehicle is off (especially when the vehicle is running at high speed), giving a good drive feeling, and wear on the electromagnetic clutch's friction surface is significantly reduced compared to conventional models, resulting in a long service life. Become.

Furthermore, even if the amount of refrigerant supplied to the compressor is reduced by controlling the opening and closing of the switching valve, various effects such as being able to suppress the temperature rise in the working chamber to approximately the same level or lower than that of the conventional system can be achieved.

[Brief explanation of drawings]

Fig. 1 is a piping diagram of a refrigeration cycle of a vehicle air conditioner incorporating an embodiment of the compressor according to the present invention, and Fig. 2 (al,
fb) and (C) are explanatory diagrams showing the relationship between one operating cycle time of the compressor and the ratio of the opening/closing time of the on-off valve during this time, respectively. Figures 3 and 4 are vane-type rotary compression of a vehicle air conditioner. Fig. 3 shows a front sectional view of the compressor, Fig. 4 shows a side sectional view of the compressor, and Fig. 5 shows a piping diagram of the refrigeration cycle of a vehicle air conditioner incorporating a conventional compressor. be. 10A, IOB... Working chamber, 14... Piping (suction side flow path), 20...
・Compressor, 22A, 22B... 2-point 2-position electromagnetic switching valve (on/off valve).

Claims (1)

[Claims] In a compressor for a vehicle air conditioner having a single or multiple working chambers for compressing refrigerant, an on-off valve is provided in the suction side flow path for supplying refrigerant to the working chamber, and the on-off valve during one operation cycle time of the compressor. 1. A compressor for a vehicle air conditioner, characterized in that the amount of refrigerant discharged is controlled by controlling the opening/closing time ratio of the compressor.