JPH04217762A - Air-conditioning device - Google Patents

Abstract

PURPOSE:To detect an accurate proper filling time by a method wherein, in an air-conditioning device having an optical type refrigerant state detector, a reference value (voltage) based on which proper filling is judged is set according to capacity of a compressor. CONSTITUTION:A flow meter 23 is located in the middle of a piping 2 which is positioned on the delivery side of a compressor 3 and through which a refrigerant F is circulated and a flow rate Q of a refrigerant is detected as delivery capacity of the compressor 3. Based on a flow rate Q, a reference value Vi for judging proper filling is variably set based on the flow rate Q. The reference value Vi is compared with a detecting voltage V of a flow sensor 9, and when the flow rate Q is high, the reference value Vi is decreased, and when the flow rate Q is low, the reference value Vi is increased to judge proper filling. This constitution prevents the occurrence of overfilling with refrigerant and deficiency in refrigerant and enables accurate detection of a proper filling time.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner suitably used as a cooling system for automobiles, and more particularly to an air conditioner equipped with an optical refrigerant state detector for detecting the state of refrigerant in a flow path.

0002

[Prior Art] Generally, automobiles, houses, etc. have air conditioners,
It is equipped with an air conditioner such as a heating system to supply warm or cool air into the room.

[0003] Here, FIGS. 5 to 7 show a cooling device for an automobile as a conventional air conditioner and will be described.

In the figure, reference numeral 1 indicates a cooling cycle, and the cooling cycle 1 includes a pipe 2 forming a circulation passage in which a refrigerant F such as ammonia or Freon gas circulates, and a pipe 2 in the direction of circulation of the refrigerant F ( It consists of a compressor 3, a condenser 4, and an evaporator 5, which are arranged in sequence along the direction of arrow A in the figure, and the evaporator 5 has its endothermic surface facing into the operator's cab (not shown). It looks like this. On the other hand, compressor 3
is driven by the rotational output of an engine (not shown). After being compressed by the compressor 3, the refrigerant F passes through the condenser 4 and the evaporator 5, and undergoes a phase transition from high-pressure gas to high-pressure liquid to low-pressure gas, and in the evaporator 5, the liquid changes to gas. When the phase transition occurs, heat is removed from the inside of the driver's cab to cool the inside of the driver's cabin.

A receiver tank 6 is located between the condenser 4 and the evaporator 5 and is provided in the middle of the pipe 2 to temporarily store the refrigerant F in a liquid state. A window 6A is provided through which the liquefaction status of the refrigerant F can be visually observed.

As shown in FIG. 6, the receiver tank 6 is connected to an inlet pipe 2A and an outlet pipe 2B which form part of the piping 2, and a dehumidifier 9 is disposed inside the receiver tank 6. Then, the receiver tank 6 introduces the gas-liquid mixed refrigerant from the condenser 4 through the introduction pipe 2A, and while dehumidifying the moisture in the refrigerant F with the dehumidifier 7, the refrigerant F in a liquid (liquid phase) state is made to flow in the direction of arrow A from the outlet pipe 2B toward the expansion valve 8, which will be described later.

Reference numeral 8 denotes an expansion valve located between the receiver tank 6 and the evaporator 5 and provided in the middle of the pipe 2. The expansion valve 8 is constituted by a pressure reducing valve, etc. The refrigerant F thus discharged is reduced in pressure to a predetermined pressure and is made to flow in the direction of arrow A. And the expansion valve 8
The refrigerant F, whose pressure has been reduced in pressure, evaporates while flowing through the evaporator 5, becomes a gaseous state, and is compressed again by the compressor 3.

Reference numeral 9 indicates an optical flow sensor as a refrigerant state detector located between the receiver tank 6 and the expansion valve 8 and provided in the middle of the outlet pipe 2B of the piping 2. As shown in FIG. 5, it is composed of an optical detector consisting of a light-emitting element 9A as a light-emitting part and a light-receiving element 9B as a light-receiving part, which are disposed facing each other in the middle of the outlet tube 2B.
It is detected whether the refrigerant F flowing in the direction of arrow A within the outlet pipe 2B is in a liquid phase state.

That is, since the refrigerant F in the liquid phase has high light transmittance, the light receiving element 9B of the flow sensor 9 is similar to the light emitting element 9.
The flow sensor 9 receives the light from A through the refrigerant F.
Detection voltage V as a detection signal from is at a higher level than the predetermined voltage Vi shown in FIG. On the other hand, when the refrigerant F in the pipe 2 leaks to the outside and becomes insufficient, the refrigerant F in a gas-liquid mixed state flows through the outlet pipe 2B, reducing the light transmittance. As a result, the amount of light received by the light receiving element 9B of the flow sensor 9 decreases, and the detected voltage V reaches the predetermined voltage Vi.
It will be lower than that.

Reference numeral 10 indicates a warning lamp 11 when the refrigerant is properly filled.
The control circuit 10 is connected to the flow sensor 9 on the input side and to the notification lamp 11 on the output side. Then, when the refrigerant F in the pipe 2 reaches an appropriate filling amount, the control circuit 10 controls the notification lamp 11 based on the detected voltage V from the flow sensor 9 which becomes higher than the reference voltage Vi as a reference value is turned on to notify the operator that the refrigerant F in the pipe 2 has reached the appropriate amount.

In the conventional technology configured as described above, for example, when the cooling cycle 1 is installed in an automobile, a refrigerant F such as Freon gas containing lubricating oil is filled into the pipe 2, and the air conditioner switch (not shown) is turned on. The compressor 3 is driven by the input, and the cooling cycle 1 is operated. Thereby, the refrigerant F in the pipe 2 is compressed and allowed to flow in the direction of the arrow A.

While flowing through the condenser 4, this refrigerant F is condensed into a gas-liquid mixed state, separated into gas and liquid in the receiver tank 6, and the refrigerant F in the liquid phase is passed through the expansion valve 8. The air flows into the evaporator 5, and while it evaporates (vaporizes) in the evaporator 5, it cools the inside of the driver's cabin while removing heat from the inside of the driver's cabin, becomes a gas phase, and is again compressed by the compressor 3.

On the other hand, the flow sensor 9 is connected to the receiver tank 6.
It is detected whether the refrigerant F derived from the Bubbles are generated, and the amount of light received by the light receiving element 9B is reduced.
The detected voltage V is lower than a predetermined voltage Vi serving as a reference value. Therefore, the control circuit 10 turns off the notification lamp 11 based on the detected voltage V to notify the operator that the amount of refrigerant F is insufficient.

When the refrigerant is filled from the outside into the pipe 2 as shown in FIG. 7 using a refrigerant filling device (not shown), when the refrigerant F reaches the appropriate filling amount, the refrigerant F enters the liquid phase. The bubbles in the refrigerant F disappear at the bubble extinction point P, and the amount of light received by the light receiving element 9B increases, so the detection voltage V becomes higher than the reference voltage Vi, and the control circuit 10 lights up the notification lamp 11 to start the work. informs the person that refrigerant F is properly filled.

[0015]

[Problems to be Solved by the Invention] However, in the above-mentioned prior art, when filling the pipe 2 with refrigerant using a refrigerant filling device or the like, the same predetermined voltage Vi is applied to the compressors 3 having different discharge capacities. Appropriate filling is determined by . However, the appropriate amount of refrigerant to be charged differs depending on the discharge capacity of the compressor 3. When using a compressor 3 with a large discharge capacity, it is necessary to reduce the amount of refrigerant charged, and when using a compressor 3 with a small discharge capacity, it is necessary to reduce the amount of refrigerant charged. It is necessary to increase the amount of filling.

For this reason, in the prior art, when a compressor 3 with a large discharge capacity is used, the amount of refrigerant charged becomes larger than the appropriate amount, resulting in overfilling, and the cooling cycle 1
There is a problem that the pressure of the refrigerant F inside becomes excessively high, making it easy to cause refrigerant leakage, and the load on the compressor 3 becomes high, causing the compressor 3 to seize. On the other hand, if a compressor 3 with a small discharge capacity is used, the amount of refrigerant charged will be less than the appropriate amount, resulting in a refrigerant shortage, and the refrigerant F in the cooling cycle 1 will be circulated without refrigerant. There is a problem in that efficiency is significantly reduced.

The present invention was developed in view of the problems of the prior art described above, and the present invention prevents refrigerant overfilling and refrigerant shortage by changing the reference value for proper refrigerant charging according to the discharge capacity of the compressor. It is an object of the present invention to provide an air conditioner that can prevent such problems and improve reliability by properly filling refrigerant.

[0018]

[Means for Solving the Problems] A feature of the configuration adopted by the present invention in order to solve the above-mentioned problems is that the structure is located on the discharge side of the compressor and is provided in the middle of a flow path through which refrigerant circulates. a flow rate/flow rate detection means for detecting the flow rate or flow rate of the refrigerant flowing through the channel; and a flow rate/flow rate detection means that corresponds to the discharge capacity of the compressor based on a signal from the flow rate/flow rate detection means when filling the flow path with refrigerant. a reference value setting means for variably setting a reference value set by the refrigerant state detector; and a filling state determining means for determining whether or not the filling state has been exceeded.

[0019]

[Operation] With the above configuration, the flow rate or flow rate of the refrigerant circulating in the flow path can be detected as the discharge capacity of the compressor based on the signal from the flow rate/flow rate detection means, so this flow rate or flow rate can be used to determine the appropriate charging of the refrigerant. The reference value can be set variably, and if the discharge capacity of the compressor is large, by lowering the reference value, it is determined that the detection signal from the refrigerant condition detector is at a relatively low level as proper filling, and the compressor When the discharge capacity is small, by increasing the reference value, it can be determined that proper filling is being performed when the detection signal from the refrigerant state detector is at a relatively high level.

[0020]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4. In the embodiment, the same components as those in the prior art described above are given the same reference numerals, and their explanations will be omitted.

In the figure, reference numeral 21 indicates a refrigerant charger provided outside the cooling cycle 1, and the charger 21 is connected to the refrigerant inlet pipe 22 connected to the pipe 2 on the upstream side of the compressor 3. 2 is connected. Then, the filling device 2
Reference numeral 1 generally consists of a cylinder in which refrigerant is stored and an on-off valve (both not shown). By opening the on-off valve while the compressor 3 is driven, the refrigerant in the cylinder is released. Introduced into the piping 2 via the introduction pipe 22,
The cooling cycle 1 is filled with refrigerant.

23 is located on the discharge side of the compressor 3,
A flow meter is shown as a flow rate/flow rate detection means installed in the middle of the pipe 2 through which the refrigerant F circulates, and the flow meter 23 is used to detect the refrigerant F discharged by the compressor 3 and flowing through the pipe 2.
A control unit 2 detects the flow rate Q or flow velocity v (hereinafter referred to as "flow rate Q") and sends the detection signal to be described later.
It is designed to output to 4. In addition, as a flowmeter, use an appropriate flow rate meter such as a Karman vortex flowmeter or an ultrasonic flowmeter.
A flow meter can be used.

Reference numeral 24 indicates a control unit composed of a microcomputer, etc., and the input side of the control unit 24 has an air conditioner switch 25 and a flow control unit.
It is connected to the sensor 9, flow meter 23, etc., and the output side is connected to the notification lamp 11, etc. The control unit 24 stores a program shown in FIG. 4 in its memory circuit, and performs an appropriate filling state determination process for determining whether or not the refrigerant F flowing through the pipe 2 has reached an appropriate filling amount. It is designed to do this. In addition, the control unit 2
4 has a flowmeter 2 in its storage area 24A.
A characteristic map (see FIG. 3) for variably setting the set voltage Vi0 as a reference value based on the flow rate Q of the refrigerant flowing in the pipe 2 (i.e., the discharge capacity of the compressor) detected in step 3 is stored.

The air conditioner according to this embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.

The proper filling state determination process by the control unit 24 will now be described with reference to FIG.

First, by starting the process, the air conditioner switch 25 is turned on to operate the compressor 3, and the on-off valve of the filler 21 is opened to start charging refrigerant from the cylinder. Piping 2 from total 23
The flow rate Q of the refrigerant flowing therein is detected, and in step 2, the set voltage ViO corresponding to this flow rate Q is read out from the characteristic map shown in FIG. Then, in step 3, this set voltage ViO is set as a predetermined voltage Vi as a reference value.

Furthermore, in step 4, the flow sensor 9
The detected voltage V corresponding to the state of the refrigerant F flowing in the pipe 2 is read from
It is determined whether or not it is larger than i, and when the determination is "NO", the detected voltage V is lower than the predetermined voltage Vi. Repeat the following process. Then, when it is determined as "YES" in step 5, the detected voltage V becomes higher than the predetermined voltage Vi, and it can be determined that the pipe 2 is filled with an appropriate amount of refrigerant F, so the process moves to step 6 and the alarm is sent. The lamp 11 is turned on to notify the operator that the refrigerant F has been properly filled. Thereafter, this process is stopped by stopping the compressor 3 and closing the on-off valve of the filling device 21.

Thus, according to this embodiment, the flowmeter 23
When the flow rate Q (i.e., the discharge capacity of the compressor) detected by This allows the notification lamp 11 to accurately notify when the fuel is properly filled. The amount of refrigerant filled into the pipe 2 can be set to a small amount, and overfilling can be reliably prevented during refrigerant filling.

On the other hand, when the flow rate Q detected by the flow meter 23 (that is, the discharge capacity of the compressor) is small, the predetermined voltage Vi is set high, so that the compressor 3
The level of the appropriate filling amount can be lowered in accordance with the discharge volume, and the notification lamp 11 can accurately notify when the filling is appropriate. Further, the amount of refrigerant filled into the pipe 2 can be set to be large, and a shortage of refrigerant can be reliably prevented during refrigerant filling.

Therefore, in this embodiment, the appropriate amount of refrigerant can always be filled into the cooling cycle 1 regardless of the discharge capacity of the compressor 3.
It is possible to prevent variations in cooling capacity due to differences in types, etc.

Furthermore, as described in the prior art, it is possible to prevent overfilling of the refrigerant F, which tends to occur when a compressor 3 with a large discharge capacity is used, thereby preventing excessive pressure in the cooling cycle 1. This makes it possible to effectively prevent the piping 2 from bursting and refrigerant leakage, and to protect the compressor 3 by preventing a high load from being applied to the compressor 3. As a result, the life of the cooling device can be effectively extended.

In the above embodiment, steps 1 to 3 of the program shown in FIG. 4 are specific examples of the reference value setting means which are constituent elements of the present invention, and steps 4 to 3 are
Step 6 shows a specific example of the filling state determining means.

Furthermore, in the above embodiment, when the refrigerant is properly filled, the notification lamp 11 is turned on to notify the driver, but instead of this, an alarm buzzer, a voice synthesizer, etc. may be used. It is also possible to notify when the refrigerant is properly filled.

Furthermore, in the process shown in FIG. 4, although the determination process is performed based on the flow rate Q measured by the flowmeter, it goes without saying that the determination process may also be performed based on the flow velocity v.

[0035]

As described in detail above, according to the present invention, a flow rate/flow rate detection means for detecting the flow rate or flow rate of refrigerant is provided on the discharge side of the compressor, and a reference value is determined based on the signal from the flow rate/flow rate detection means. The value setting means variably sets a reference value corresponding to proper refrigerant filling, and the filling state determining means compares this reference value with a detection signal from a refrigerant state detector, and when the detection signal exceeds the reference value. Since the system is configured to determine when the refrigerant is properly filled, if the flow velocity or flow rate (compressor discharge capacity) is large, it is possible to reduce the amount of refrigerant filled into the flow path by setting a low reference value. This can prevent overfilling of the refrigerant in the flow path. On the other hand, if the flow velocity or flow rate (compressor discharge capacity) is low, the amount of refrigerant filled in the flow path can be increased by setting a high reference value, which may result in a shortage of refrigerant in the flow path. can be prevented. Thereby, regardless of the type of compressor, it is possible to accurately fill the refrigerant in an appropriate amount according to the discharge capacity of the compressor, and it is possible to prevent variations in cooling capacity.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a state in which refrigerant is filled into a cooling device according to an embodiment of the present invention.

FIG. 2 is a control block diagram.

FIG. 3 is an explanatory diagram showing a characteristic map of the set voltage with respect to the flow rate of refrigerant stored in the storage area of the control unit.

FIG. 4 is a flow chart showing a refrigerant appropriate filling determination process.

FIG. 5 is a circuit diagram showing a cooling device according to the prior art.

FIG. 6 is an explanatory diagram showing a receiver tank and the like.

FIG. 7 is a characteristic diagram showing the detection voltage of the flow sensor.

[Explanation of symbols]

1 Cooling cycle 2 Piping 3 Compressor 4 Condenser 5 Evaporator 9 Flow sensor (refrigerant state detector) 9A Light emitting element (light emitting part) 9B Light receiving element (light receiving part) 23 Flow meter 24 Control unit F Refrigerant

Claims (1)

[Claims] 1. A flow path in which a refrigerant circulates, a condenser and an evaporator provided in the middle of the piping forming the flow path, and a condenser and an evaporator located between the condenser and the evaporator of the piping. A compressor is provided in the middle of the flow path to compress the refrigerant in the pipe, and the refrigerant compressed by the compressor is in a liquid phase. An air conditioner comprising an optical refrigerant state detector that detects the refrigerant state in the flow path,
A flow rate/flow rate detection means located on the discharge side of the compressor and provided in the middle of the flow path to detect the flow rate or flow rate of the refrigerant flowing in the flow path, and when filling the flow path with refrigerant. a reference value setting means for variably setting a reference value corresponding to the discharge capacity of the compressor based on the signal from the flow rate/flow rate detection means; An air conditioner comprising: a filling state determining means for determining whether a detection signal from the refrigerant state detector exceeds a reference value set by the reference value setting means.