JPS58209613A - Compressor control device - Google Patents

Abstract

PURPOSE:To maintain the interior of a car compartment always at a confortable temperature by specifying the recovery temperature of the thermal switch of a compressor which puts an electromagnetic clutch in OFF state by means of said switch when the temperature of ejected gas from the compressor exceeds a predetermined value. CONSTITUTION:A car air-conditioner performs air conditioning through condensation and decompression of refrigerant ejected from a compressor 3 rotated by means of an engine through an electromagnetic clutch 2 and subsequent supply of said refrigerant to an evaporator. Said clutch 2 is cut off when the temperature of ejected gas from the compressor detected by means of a thermal switch 7 provided on a compressor case 10 exceeds a predetermined value. In this case, the thermal switch 7 is formed by providing between a heat insulating case 16 and a case 15 a saucer-like bimetal 17 sensing the temperature of said case 10. Further, the temperature of said case 10 dropped, during the time from OFF of the thermal switch 7 until rise of the temperature in a compartment by 2-4 deg.C, is set as the recovery temperature of said switch 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compressor control device that safely protects a compressor from seizure and the like.

Generally, as shown in FIG. 1, an air conditioner 1 for an automobile uses high-temperature and high-pressure refrigerant sent from a compressor 3 connected to an engine (not shown) via an electromagnetic clutch to a condenser 4.
The refrigerant is cooled, liquefied, and adiabatically expanded in an expansion valve 5. The refrigerant discharged from the expansion valve 5 is heat-absorbed and vaporized in an evaporator 6, and then returned to the compressor 3, and has a so-called cooling cycle system. are doing.

In this type of installation, lubricating oil is circulated together with the refrigerant throughout the cooling cycle system, and this lubricating oil lubricates the parts within the compressor 3 that require lubrication, thereby preventing the compressor from seizing.

The thermal switch 7, which is provided to prevent seizure of the compressor 3, detects the discharge gas salt from the compressor 3, and when the temperature of the discharge gas reaches a certain value, the compressor 3 is activated due to the lack of return refrigerant. The electromagnetic clutch 2 is disengaged to prevent seizure.

F91'' Let us consider the case where a car is running in third gear with 100% refrigerant charged. When the compressor 3 is directly connected to the engine and the engine is rotated at high speed, the amount of gas discharged from the compressor 3 will increase as the engine rotates, but the 4°C temperature of the expansion valve 5 will vary depending on the temperature inside the vehicle. Since the opening is adjusted, the flow of the increasing refrigerant is blocked by the expansion valve 5, and the amount of refrigerant returned to the compressor is determined by the amount of gas discharged from the compressor. This causes an increase in the compressor discharge gas temperature.

Similarly, if the amount of refrigerant sucked is small, the amount of refrigerant sucked in is small.If the compressor 3 rotates at high speed, the amount of work of the compressor 3 will increase, which will be converted into heat, and the temperature of the discharged gas will rise. As the amount of refrigerant returned to the compressor decreases, the amount of lubricating oil also decreases, which makes it easier for frictional heat to occur in the compressor itself, and the compressor itself becomes a temperature sensor. (This tendency is clearly seen in Figure 2. In other words, the time it takes to reach the compressor off-point temperature becomes faster as the engine shifts to 2nd and 1st gears. If the compressor is turned off by turning the engine once, during normal driving, the thermal switch will stop the compressor by simply rotating the engine at high speed, causing the interior of the vehicle to gradually become hotter. Therefore, there is a possibility that passengers may think that the air conditioning system for automobiles has malfunctioned.

Moreover, due to the nature of this thermal switch, in order to turn it back on after it has been turned off, the compressor must reach a negative temperature, and as mentioned above, if it is turned off during normal driving, it will almost never turn back on. Since there is no such thing, there is a high possibility that the above-mentioned inconvenience will occur.

However, the reason why the thermal switch is turned off is because the temperature of the discharged gas becomes high, and because there are few gamma oil covers, the thermal switch is rarely turned off. Therefore, it is possible to rotate the compressor even in a state where the discharge gas is not yet stable, such as when this thermal switch is turned off.

According to Futan, results were obtained that the compressor could be rotated for about 20 hours even when such high-temperature discharge gas was flowing out.

Taking this into account, even after the compressor is in the pure land, the thermal switch can be reset and the compressor can be operated if the occupants inside the vehicle become uncomfortable due to the rise in temperature inside the vehicle. become.

This invention was developed in view of the diagonal aspect of the present invention, and even if the electromagnetic clutch is disengaged because the engine rotates at high speed during normal driving, if the temperature inside the vehicle rises to a point where people feel uncomfortable, the engine will rotate at high speed. The purpose is to provide an automotive air conditioner that resets the thermo switch and starts the compressor in order to give priority to indoor temperature control. The point is that the compressor case temperature, which has decreased while the vehicle interior temperature rises by 2 to 4 degrees Celsius from the time of turning off, is set as the return temperature of the thermal switch.

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

FIG. 3 is an explanatory diagram showing one embodiment of the present invention, and the same members as those shown in FIG. 1 are given the same reference numerals.

This compressor control device c includes a compressor case 1
The case 15 of the thermal switch 7 is screwed near the 0 discharge point, the 4 wires 11 of this thermal switch are connected to the ground, the conductor 12 is connected to the coil of the clutch 2 (not shown)
and is connected to the power supply 14 via the air conditioner switch 13.

The thermal switch 7 has a heat insulating resin case 16 inside a case 15, and a plate that deforms by sensing the temperature of the compressor case 1o is provided between the bottom 16a of the resin case 16 and the bottom 15a of the case 15. shaped bimetal 17
has been established. An actuating rod 18 is mounted on this bimetal 17 and is inserted through the bottom 16a of the resin case 16, and pushes up a connector 19 whose end is connected to the front conductor 12. : The connection with the connected contact 2o is maintained.

21 in the figure is a heat insulating resin.

First, the compressor control device according to the present invention*: The c-7 switch 7 changes the operating point of the bimetal 17, for example, when the temperature of the compressor case 10 reaches 165°C.
The connection state of the circumferential contacts 19 and 20 is cut off, and the compressor case temperature, which has decreased while the vehicle interior temperature rises by 2 to 4 degrees Celsius (as shown in Fig. 4),
℃~80℃) is set as the recovery temperature.

That is, the temperature inside the vehicle is given priority over the condition of the compressor, and if the temperature rises by 2 to 4 degrees Celsius, which would make most people feel uncomfortable, the thermal switch 7 is turned on and the compressor 3 is restarted.

Next, the action will be explained.

For example, suppose you set the gear of your car to 3rd gear and rotate the engine at high speed. This rotation of the engine causes the compressor 3 to suddenly rotate, discharging the refrigerant to the still pressure side circuit, reducing the refrigerant noise that returns to the compressor 3 from the low pressure pump, and increasing the temperature of the discharged gas as described above.

This temperature rise causes the temperature of the compressor case 10 to which the thermal switch 7 is installed! jJ” When the temperature exceeds 165°C, the actuating rod 18 is deformed due to the deformation of the dish-shaped bimetal 17.
is pushed up and disconnects the contacts 19 and 20.

As a result, the electromagnetic clutch 2 is disengaged, the compressor 3 is disconnected from the engine, and the compressor is stopped.

However, as mentioned above, if the compressor is turned off during normal driving, the temperature inside the vehicle will gradually rise, and if this rise reaches 2 to 4 degrees Celsius, passengers will feel uncomfortable.

However, while the temperature inside the vehicle increases by 2 to 4 degrees Celsius, the compressor gradually cools down to 80 to 130 degrees Celsius.

When such a temperature condition is reached, the bimetal 17 deforms as shown in FIG. 3, and the recontractors 19 and 20 become connected.

With this connection, the electromagnetic clutch 2 connects the engine and the compressor, and the compressor is restarted.

By starting the compressor, the interior of the vehicle is cooled and the discomfort of the occupants is alleviated.

In addition, in the above-mentioned embodiment, the off point of the bimetal 17 of the thermal switch 7? Night degree is 165℃, return temperature is 80~
Although the temperature is set to 130° C., the present invention is not limited to this in any way, and can be easily changed as appropriate depending on the type of vehicle or the driving conditions of the vehicle.

As is clear from the above explanation, according to the present invention, from the time the thermal switch is turned on, the temperature inside the vehicle increases by 2 to 4 degrees.
The temperature of the compressor case, which decreased while the temperature was rising, is used as the return temperature of the thermal switch, so even if the air conditioner turns off due to engine rotation and the air conditioning in the passenger compartment stops, the occupants will not feel uncomfortable. As soon as the air conditioner is felt, cooling operation is started, and the air inside the vehicle can be kept comfortable at all times. Moreover, this prevents undesirable problems such as burning out of the compressor.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the circuit of a conventional automobile air conditioner, Fig. 2 is a graph showing the state in which the thermal switch is turned off depending on the vehicle speed, and Fig. 3 is an explanatory diagram showing an embodiment of the present invention. , FIG. 4 is a graph showing the relationship between the vehicle interior temperature and the return temperature of the thermal switch. 2... Electromagnetic clutch, 3... Compressor, 4... Capacitor, 5... Expansion valve, 6... Evaporator, 7...
Thermal switch, 10 ・Compressor case, 17
...Dish-shaped bimetal.

Claims (1)

[Claims] (2) By rotating a compressor connected to the engine via an electromagnetic clutch, a cooling cycle system is constructed in which the refrigerant sent out is returned to the compressor via a condenser, an expansion valve, an evaporator, etc., and the gas discharged from the compressor is When the temperature exceeds a certain value,
In an automotive air conditioner in which a thermal switch that disengages the electromagnetic clutch is attached to a compressor, the case temperature of the compressor decreases while the temperature inside the vehicle increases by 2 to 4 degrees Celsius from the time the thermal switch is turned off. A compressor control device in which the temperature is set as the return temperature of the thermal switch.