JPS6353474B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigerant amount display device for a vehicle air conditioning unit that detects the remaining amount of refrigerant used for cooling the air conditioning unit.

Conventionally, as a cooling unit used in a vehicle air conditioner, there is one shown in FIG. 1, for example.

In FIG. 1, reference numeral 1 denotes a liquid tank that stores a refrigerant liquid for cooling, and a sight glass 2 is provided at a refrigerant outlet portion of the liquid tank 1 so that the flow of the refrigerant can be seen from the outside. The refrigerant from the liquid tank 1 is vaporized into a mist by the expansion valve 3 to form a gas-liquid mixture, and then sent to the evaporator 4 through which air from the blower fan 5 is flowing, cooling the flowing air. The refrigerant is adiabatically compressed and liquefied in the compressor 6, then radiated by the condenser 7, and returned to the liquid tank 1 again to perform a cooling cycle.

The drive circuit for such a cooling unit includes a relay 9 that is energized when the ignition switch 8 is turned on, and a relay 9 that is energized when the ignition switch 8 is turned on. The fan switch 10 that drives the blower fan motor 5a and the fan switch 1
A cooler switch 12 is provided which operates the magnetic clutch 6a of the compressor 6 through the contacts of a relay 11 which is energized when the compressor is turned on.

By the way, when the above-mentioned cooling unit is used for a long time, the amount of refrigerant gradually decreases due to slight leakage from the connection part, etc., and the effectiveness of the air conditioner may decrease.

Therefore, in order to know the decrease in the amount of refrigerant, by installing a sight glass 2 in the liquid tank 1 and observing the flow of refrigerant through the sight glass 2 during cooling,
Although it is possible to determine whether there is a shortage of refrigerant, the state of the refrigerant viewed through the sight glass 2 does not accurately determine whether the refrigerant is depleted.

Therefore, in the conventional unit, as shown in FIG. 1, a super heat switch 13 is provided on the discharge side of the evaporator 4, which outputs an output when the degree of superheat of the refrigerant exceeds a certain value.
A means is provided for detecting and displaying a decrease in the amount of refrigerant by extracting the output of the refrigerant via a delay timer 14 and lighting an alarm lamp 15. The degree of superheating of the refrigerant detected by this super heat switch 13 is determined when the refrigerant in a gas-liquid mixed state is detected by the evaporator 4.
It is given by the temperature difference between the temperature at which heat is removed from the flowing air and vaporized, and the saturated vapor temperature of the refrigerant at which vaporization no longer takes place. Normally, about 10℃ is appropriate, but if the temperature exceeds 10℃ It can be determined that there is not enough refrigerant.

However, in the above-mentioned device, an alarm is issued whether the refrigerant level is low while the cooling unit is operating, so for example, if the outside temperature is low, the super heat switch 13 may not operate even if the refrigerant level is low. In some cases, the operation is unstable, and the super heat switch 13 does not operate even if the amount of refrigerant is too large. There was a problem that I didn't know anything about.

The present invention has been made in view of the above, and the refrigerant liquid from the liquid tank is atomized by an expansion valve and sent to an evaporator to cool the air introduced by a blower fan, and after the refrigerant from the evaporator is adiabatically compressed by a compressor. In a device that has a refrigerant circulation path that returns the refrigerant to the liquid tank via a condenser, in order to accurately display the amount of refrigerant, the expansion valve is released from the liquid tank for a certain period of time from the time the liquid level check switch is operated. The compressor is driven while the refrigerant flow path to the refrigerant is cut off, the refrigerant in the circulation path is collected into a liquid tank, the amount of refrigerant in the collected liquid tank is detected, and whether the amount of liquid is appropriate is displayed. This is how it was done.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 2 is an explanatory diagram showing an embodiment of the present invention.

First, to explain the configuration, 1 is a liquid tank that stores refrigerant liquid, 3 is an expansion valve that atomizes the refrigerant liquid from the liquid tank 1, and 4 is a gas-liquid mixed refrigerant that has been atomized by the expansion valve 3. An evaporator that cools the flowing air, 5 a blower fan that flows air to the evaporator 4, 5a a blower fan motor that drives the blower fan 5, 6 a compressor that adiabatically compresses the refrigerant from the evaporator 4, and 6a a belt pulley. A magnetic clutch connects the transmitted rotation of the engine to the compressor 6, and 7 is a condenser that radiates heat from the refrigerant compressed and liquefied by the compressor 6. The configuration of such a cooling unit is similar to the conventional one shown in FIG. It will be the same as the device. In addition, as a drive circuit for the above-mentioned cooling unit, 8 is a relay 9 which is connected by switch operation.
10 is a fan switch that is turned on to drive the blower fan motor 5a; 12 is a relay that is activated when the fan switch 10 is turned on; This is a cooler switch for operating the magnetic clutch 6a of the compressor 6 through 11 relay contacts.

In addition to such a configuration, in the present invention, a liquid level check switch 16 is provided in parallel with each of the fan switch 10 and the cooler switch 12, and
A timer 18 outputs a fluid level check signal for a certain period of time from when the fluid level check switch 16 is operated during engine startup, and power is supplied to the compressor 6 while the signal from this timer 18 is being output. At the same time, a relay 17 is provided for supplying power to a solenoid valve 20 provided in the refrigerant flow path from the liquid tank 1 to the expansion valve 3. The solenoid valve 20 is energized via the relay contact 17c of the relay 17, which is energized when the liquid level check switch 16 is turned on.
When this electricity is applied, it operates to cut off the refrigerant flow path. Relay contact 17a of relay 17 is connected to operate magnetic clutch 6a of compressor 6, and relay contact 17b is connected to drive blower fan motor 5a. In this embodiment, the relay 17, relay contacts 17a, 17c, and solenoid valve 20 constitute the refrigerant recovery means of the present invention.

On the other hand, a liquid level sensor 21 for detecting the amount of refrigerant is provided in the liquid tank 1. For example, as shown in the figure, the liquid level sensor 21 detects the level of the refrigerant in the liquid tank 1. A liquid level detection means that detects the movement of the float up and down as a voltage change due to a variable resistor, or a capacitance type liquid level detection means that detects and outputs changes in capacitance due to changes in the liquid level is used. It will be done. The output of the liquid level sensor 21 having such a configuration is connected to the display meter 22.
The display section has display bands that indicate large, appropriate, and small depending on the detected liquid level, and the amount of refrigerant is displayed by the deflection of the pointer. Furthermore, the timer 18 that is activated when the fluid level check switch 16 is turned on is set to a period of several seconds to several tens of seconds, and the timer 18 deenergizes the relay 17 after this set time. Become.

Next, the operation of the present invention will be explained.

If you want to check the refrigerant level, turn on the ignition switch 8 to start the engine, energize the relay 9 to supply power voltage from the battery, and then turn on the fluid level check switch in this state. 1
Turn on 6. When the liquid level check switch 16 is turned on, the timer 18 is activated, and the output of the timer 18 energizes the relay 17, which closes each of its relay contacts 17a to 17c. Therefore, the magnetic clutch 6a is driven via the relay contact 17a to rotate the compressor 6, and the blower fan motor 5a is rotated via the relay contact 17b, causing the blower fan 5 to circulate air to the evaporator 4. Further, the solenoid valve 20 is energized via the relay contact 17c, and the solenoid valve 20 blocks the refrigerant flow path from the liquid tank 1 to the expansion valve 3. Such a solenoid valve 2
By blocking the refrigerant flow path and driving the blower fan 5 and compressor 6, the expansion valve 3
The refrigerant present in each device and flow path line from A collection operation is performed. Note that driving the blower fan motor 5a to cause air to flow through the evaporator 4 through the blower fan 5 is effective in accelerating the evaporation of the refrigerant in the evaporator 4.

In this way, the refrigerant in a location other than the liquid tank 1 is recovered, and at the same time, the liquid level of the refrigerant in the liquid tank 1 is detected by the liquid level sensor 21, and the liquid level at that time is displayed on the display meter 22. A pointer is now displayed, and by looking at the display position on the display meter 22, it can be reliably determined whether the amount of refrigerant in the cooling unit is too little, too much, or an appropriate amount. Such a refrigerant amount detection display is performed by the timer 18 after a set time has elapsed since the liquid amount check switch 16 was turned on.
The refrigerant liquid level is checked until the blower fan motor 5a, magnetic clutch 6a, and solenoid valve 20 are de-energized by the deenergization of the relay 17 due to the stop of the output of the timer 18. will be terminated.

The cooling unit in the embodiment shown in FIG. 2 is operated by turning on the fan switch 10 and the cooler switch 1 with the ignition switch 8 turned on.
2 are turned on, the compressor 6 and the blower fan 5 are operated, and the evaporator 4 cools the flowing air.

Of course, when checking the amount of refrigerant mentioned above, if the amount of refrigerant is low as indicated by the display meter 22, replenish the refrigerant to the liquid tank 1, and on the other hand, if the amount of refrigerant is too large, remove the refrigerant from the liquid tank 1. Just do it.

As explained above, according to the present invention, the refrigerant liquid from the liquid tank is atomized by the expansion valve and sent to the evaporator, the flowing air is cooled by the blower fan, and the refrigerant from the evaporator is adiabatically compressed by the compressor. In a device having a refrigerant circulation path that returns the refrigerant to the liquid tank via a condenser, the compressor is driven with the refrigerant flow path from the liquid tank to the expansion valve blocked for a certain period of time from the time a liquid level check switch is operated. The refrigerant is collected in a liquid tank, and the amount of refrigerant in the collected liquid tank is detected and displayed, making it possible to confirm the amount of refrigerant being used in the cooling unit of a vehicle air conditioner. Even if the refrigerant level gradually decreases during use, it is immediately known that the refrigerant level has fallen below the appropriate level, and appropriate measures such as replenishing the refrigerant can be taken. This prevents the effectiveness of the air conditioner from decreasing, and since it can be confirmed during inspection that the amount of refrigerant is too high, it is possible to reduce the amount of refrigerant to an appropriate amount. This also has the effect of preventing a decrease in fuel consumption rate.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional device, and FIG. 2 is an explanatory diagram showing an embodiment of the present invention. 1...Liquid tank, 2...Sight glass,
3... Expansion valve, 4... Evaporator, 5... Blower fan, 5a... Blower fan motor, 6...
Compressor, 6a...Magnetic clutch, 7
... Capacitor, 8 ... Ignition switch, 9, 11, 17 ... Relay, 17a to 17c
... Relay contact, 18 ... Timer, 20 ... Solenoid valve, 21 ... Liquid level sensor, 22 ... Display meter.

Claims (1)

[Scope of Claims] 1. The refrigerant liquid in the liquid tank is atomized by an expansion valve and sent to an evaporator to cool the air introduced from the blower fan, and the refrigerant from the evaporator is compressed by a compressor and then transferred to the liquid tank via a condenser. In a device having a refrigerant circulation path that returns the refrigerant to , a refrigerant recovery means for driving the compressor with the refrigerant flow path from the liquid tank to the expansion valve blocked and recovering the refrigerant in the refrigerant circulation path to the liquid tank; and a refrigerant in the liquid tank recovered by the refrigerant recovery means. 1. A refrigerant amount display device for a vehicle air conditioning unit, comprising a liquid amount detecting means for detecting a liquid amount, and a liquid amount display means for displaying a refrigerant liquid amount based on a detected value of the liquid amount detecting means. 2. The refrigerant amount display device for a vehicle air conditioning unit according to claim 1, wherein the liquid amount display means is an indicator that displays at least when the liquid amount is large and when the liquid amount is small.