JP3635720B2 - refrigerator - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a refrigerator that uses oil having a specific gravity smaller than that of a refrigerant and that is not compatible with the refrigerant as a lubricating oil for the compressor. More specifically, the refrigerant and the lubricating oil are two-layered in the compressor. The present invention relates to a refrigerator capable of detecting separation.
[0002]
[Prior art]
Conventionally, when oil that is incompatible with a refrigerant is used in a refrigerator, as shown by a black dot in FIG. 7A, when a refrigerant having a predetermined refrigerant fraction or more is dissolved in the oil, Two-layer separation occurs in which the refrigerant separates into two layers. At this time, if (the specific gravity of the refrigerant)> (the specific gravity of the oil), the lower layer becomes a refrigerant rich layer having an extremely low oil concentration.
[0003]
As an operation mode in which two-layer separation occurs, there is a mode in which liquid back occurs transiently such as start-up (sleeping start-up), start / stop, defrost, and the like. When two-layer separation occurs in the oil reservoir portion of the compressor of the refrigerator, the two-layer separation surface D exceeds the oil filler opening S as shown in FIG. Then, the oil in the lower liquid refrigerant rich layer R is sucked in from the fuel filler port S and supplied to the sliding portion of the compressor C without the oil being sucked in from the fuel filler port S. Then, the lubrication failure of the compressor C occurs, and there is a problem that sliding portion friction and seizure occur.
[0004]
[Problems to be solved by the invention]
Therefore, an object of the present invention is to provide a refrigerator that can detect that the refrigerant and the lubricating oil are separated into two layers in the compressor.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 uses a refrigerator having a specific gravity smaller than that of the refrigerant and substantially not compatible with the refrigerant as a lubricating oil for the compressors 5 and 25. In
Oil temperature detecting means 15, 16, 31, 33 for detecting the temperature of oil in the compressors 5, 25;
Refrigerant saturation temperature detection means 7, 8, 10, 11, 27, 30, 32, 34 for detecting the saturation temperature of the refrigerant determined by the pressure in the compressors 5 and 25;
The oil temperature detected by the oil temperature detection means 15, 16, 31, 33 and the saturation temperature of the refrigerant detected by the refrigerant saturation temperature detection means 7, 8, 10, 11, 27, 30, 32, 34 In comparison, when the difference α = (the oil temperature−the saturation temperature) between the oil temperature and the saturation temperature becomes less than or equal to zero (α ≦ 0), the refrigerant and the lubricating oil are transferred to the compressor. within 5, 25 that have a two-layer separation determining means 12,18,35,37 for determining to be separated into two layers.
[0006]
Further, in the inventions of claim 1, said two-layer separation determining means 12,18,35,37 are
When the operating frequency of the compressors 5 and 25 is a predetermined value, the refrigerant and the lubricating oil are contained in the compressors 5 and 25 when the difference α is equal to or less than zero (α ≦ 0). Judging that it is separated into two layers,
When the operating frequency of the compressors 5 and 25 becomes higher than the predetermined value, the value αa obtained by increasing the difference α by an amount corresponding to the increase becomes equal to or less than zero (α ≦ 0). Determining that the refrigerant and the lubricating oil are separated into two layers in the compressors 5 and 25;
When the operating frequency of the compressors 5 and 25 becomes lower than the predetermined value, the value αa obtained by reducing the difference α by the amount of the reduction becomes zero or less (α ≦ 0). , it determined that the refrigerant and the lubricating oil and are separated into two layers inside the compressor 5,25.
[0007]
Further, the invention of claim 2 is a refrigerator using a non-compatible oil having a specific gravity smaller than that of the refrigerant and substantially not compatible with the refrigerant as a lubricating oil of the compressor.
An outside air temperature sensor 57 for detecting the outside air temperature;
When the compressor is performing a start-stop by repeating the on and off at startup, the start-stop circuit 58 for counting the start-stop number of the compressor 55 is turned off from less than 5 minutes on state,
A signal Sout representing the outside temperature from the outside temperature sensor 57 and a signal Sn representing the number of starts / stops from the start / stop circuit 58 are input, and the number of starts / stops of the compressor 55 is determined by the outside air temperature. The two-layer separation determining means for determining that the refrigerant and the lubricating oil in the compressor are separated into two layers when the predetermined number of determinations is reached, and that the separation surface is immediately before exceeding the oil supply port in the compressor. 60 is provided.
[0008]
[Action]
As shown in FIG. 8, under a predetermined pressure in the compressor, the oil temperature (more precisely, the temperature of the mixed liquid of oil and refrigerant) is higher than the saturation temperature of the refrigerant in the melting region of the refrigerant and oil. . On the other hand, in the two-layer separation zone of the refrigerant and oil, the oil temperature is approximately equal to the saturation temperature of the refrigerant. The invention of claim 1 applies the property shown in FIG.
[0009]
That is, in the refrigerator of the first aspect of the present invention, the two-layer separation determination means 12, 18, 35, 37 includes the oil temperature detected by the oil temperature detection means 15, 16, 31, 33, and the refrigerant saturation temperature detection means. The saturation temperature of the refrigerant detected by 7, 8, 10, 11, 27, 30, 32, 34 is compared. When the difference α between the oil temperature and the saturation temperature is equal to or less than zero (α ≦ 0), the determination means 12, 18, 35, and 37 It is determined that the refrigerant and the lubricating oil are separated into two layers in the compressors 5 and 25.
[0010]
Therefore, when the determination means 12, 18, 35, 37 determines that the two-layer separation is performed, an alarm is given for insufficient lubrication of the compressors 5, 25, and a two-layer separation avoidance operation is performed. Wear and seizure of the sliding portion can be prevented in advance.
[0011]
In the refrigerator of the invention of claim 1, the two-layer separation determining means 12, 18, 35, 37 is such that the difference α is less than or equal to zero when the operating frequency of the compressors 5, 25 is a predetermined value. When (α ≦ 0), it is determined that the refrigerant and the lubricating oil are separated into two layers in the compressors 5 and 25. In addition, when the operating frequency of the compressors 5 and 25 becomes higher than the predetermined value, the determination means 12, 18, 35 and 37 has a value αa which increases the difference α by the increased amount. However, when it becomes zero or less (α ≦ 0), it is determined that the refrigerant and the lubricating oil are separated into two layers in the compressors 5 and 25. Further, when the operating frequency of the compressors 5, 25 becomes lower than the predetermined value, the determination means 12, 18, 35, 37 has a value αa that decreases the difference α by the reduced amount. However, when it becomes zero or less (α ≦ 0), it is determined that the refrigerant and the lubricating oil are separated into two layers in the compressors 5 and 25.
[0012]
When the operating frequency of the compressors 5 and 25 is increased, it is difficult to separate the two layers even if the difference α is the same value. On the other hand, when the operating frequency of the compressors 5 and 25 is decreased, the difference α is the same value. However, it becomes easy to separate the two layers. Therefore, as in the first aspect of the invention, when the operating frequency of the compressors 5 and 25 increases or decreases with respect to a predetermined value, the determination means 12, 18, 35 and 37 increase or decrease the value α which is the determination reference value. By doing so, the two-layer separation determination in the compressors 5 and 25 can be performed more accurately.
[0013]
By the way, when the compressor is repeatedly turned on and off at startup, the refrigerant liquid returns to the compressor each time it is turned on, and the refrigerant accumulates in the compressor. Then, when the refrigerant accumulated in the compressor reaches a predetermined amount, two-layer separation in which the refrigerant and oil are separated into two layers occurs. The invention according to claim 2 detects the two-layer separation by utilizing the correlation between the number of times of starting and stopping and the occurrence of the two-layer separation.
[0014]
That is, according to the invention of claim 2 , when the two-layer separation determining means 60 has reached a predetermined determination number determined by the outside air temperature, the number of times that the compressor 55 is turned off from the on state is reached. It is determined that the refrigerant and the lubricating oil in the compressor 55 are separated into two layers, and this separation surface is just before the oil supply port in the compressor 55 is exceeded.
[0015]
Therefore, if the determination means 60 determines that the two-layer separation surface is just before the oil filler opening, an insufficient lubrication alarm is issued and the two-layer separation avoidance operation is performed. It is possible to prevent burn-in.
[0016]
【Example】
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0017]
[First embodiment]
FIG. 1 shows the configuration of an air conditioner as a first embodiment of the present invention. The air conditioner includes an indoor heat exchanger 1, an outdoor heat exchanger 2, a throttle expansion unit 3, a four-way switching valve 4, a compressor 5, and an accumulator 6 that are connected to each other through refrigerant lines. In this air conditioner, oil having a specific gravity smaller than that of the refrigerant used in the air conditioner and having no compatibility with the refrigerant is used as the lubricating oil.
[0018]
A first temperature sensor 7 is attached to the indoor heat exchanger 1. A second temperature sensor 8 is attached to the outdoor heat exchanger 2. The first and second temperature sensors 7 and 8 are connected to the input value selection unit 10. The input value selection unit 10 is connected to a pipe pressure loss correction calculation unit 11. Further, the calculation unit 11 is connected to the comparison unit 12.
[0019]
On the other hand, a third temperature sensor 15 is connected to the discharge pipe 13 from the compressor 5, and the third temperature sensor 15 is connected to the oil temperature correction calculation unit 16. The calculation unit 16 is connected to the comparison unit 12.
[0020]
The comparison unit 12 is connected to the frequency correction unit 17, and the frequency correction unit 17 is connected to the two-layer separation determination unit 18.
[0021]
The air conditioner having the above configuration determines the two-layer separation between the refrigerant and the lubricating oil in the compressor 5 based on the temperatures detected by the first, second, and third temperature sensors 7, 8, and 15. The operation | movement which performs is demonstrated.
[0022]
First, the input value selection unit 10 receives a signal S1 representing the temperature T1 of the indoor heat exchanger 1 from the first temperature sensor 7, and a signal S2 representing the temperature T2 of the outdoor heat exchanger 2 from the second temperature sensor 8. Receive. As shown in the lower part of FIG. 1, the input value selection unit 10 selects and outputs a signal S2 representing the temperature T2 of the outdoor heat exchanger 2 during cooling when the compressor 5 is a high-pressure dome type. On the other hand, the signal S1 representing the temperature T1 of the indoor heat exchanger 1 is selected and output during heating. When the compressor 5 is a low-pressure dome type, the selection unit 10 selects and outputs a signal S1 indicating the temperature T1 of the indoor heat exchanger 1 during cooling, while the temperature of the outdoor heat exchanger 2 during heating. A signal S2 representing T2 is selected and output.
[0023]
In the case where the compressor 5 is a high-pressure dome type, and during cooling, the pipe pressure loss correction calculation unit 11 supplies the outdoor heat from the discharge pipe 13 to the temperature (condensation temperature) T2 of the outdoor heat exchanger 2. The pressure loss converted temperature ΔTpc obtained by converting the pressure loss up to the exchanger 2 (condenser) into a temperature is added to calculate an added value (T2 + ΔTpc). Then, this added value (T2 + ΔTpc) is converted into the pressure Pc in the dome of the compressor 5, and the saturation temperature Ts of the refrigerant in the dome is calculated from the converted pressure in the dome Pc.
[0024]
Further, when the compressor 5 is a high-pressure dome type and heating is performed, the pipe pressure loss correction calculation unit 11 supplies the temperature (condensation temperature) T1 of the indoor heat exchanger 1 to the indoor heat exchanger 1 from the discharge pipe 13. The pressure loss converted temperature ΔTph obtained by converting the pressure loss up to (condenser) into temperature is added to calculate an added value (T1 + ΔTph). Then, this added value (T2 + ΔTph) is converted into the dome pressure Ph of the compressor 5, and the saturation temperature Ts of the refrigerant in the dome is calculated from the converted dome pressure Ph.
[0025]
In the case where the compressor 5 is a low-pressure dome type, and during cooling, the pipe pressure loss correction calculation unit 11 converts the pressure loss from the indoor heat exchanger 1 to the suction pipe into a pressure loss converted temperature ΔTpc. Is subtracted from the temperature (evaporation temperature) T1 of the indoor heat exchanger 1 to calculate a subtraction value (T1-ΔTpc). Then, the subtraction value (T1−ΔTpc) is converted into the pressure Pc in the dome of the compressor 5, and the saturation temperature Ts of the refrigerant in the dome is calculated from the converted pressure Pc in the dome.
[0026]
In the case where the compressor 5 is a low-pressure dome type and heating is performed, the pipe pressure loss correction calculation unit 11 converts the pressure loss from the outdoor heat exchanger 1 to the suction pipe into a pressure loss converted temperature ΔTph. Is subtracted from the temperature (evaporation temperature) T2 of the outdoor heat exchanger 2 to calculate a subtraction value (T2−ΔTph). Then, the subtraction value (T2−ΔTph) is converted into the dome pressure Ph of the compressor 5, and the saturation temperature Ts of the refrigerant in the dome is calculated from the converted dome pressure Ph.
[0027]
On the other hand, the oil temperature correction calculation unit 16 receives the signal S3 output from the discharge pipe temperature sensor 15, corrects the discharge pipe temperature T3 indicated by the signal S3, and sets the oil temperature To in the compressor 5 to the temperature To. calculate.
[0028]
Next, the comparison unit 12 receives a signal representing the saturation temperature Ts from the pipe pressure loss correction calculation unit 11 and receives a signal representing the oil temperature To from the oil temperature correction calculation unit 16. Then, the comparison unit 12 compares the saturation temperature Ts with the oil temperature To, and subtracts the saturation temperature Ts from the oil temperature To to obtain the difference α = (oil temperature To) − (saturation temperature Ts). calculate.
[0029]
Next, the frequency correction unit 17 receives a signal representing the driving frequency of the compressor 5 and adds a correction value Δ to the difference α in accordance with the driving frequency, thereby correcting the difference αa = (α + Δ). Is calculated. The relationship between the correction value Δ and the drive frequency is directly proportional, and is 0 ° C. when the drive frequency is 60 Hz, as shown in FIG. The reason for performing such frequency correction is that if the drive frequency is lower than the predetermined frequency (60 Hz), the stirring effect cannot be obtained up to the bottom of the compressor 5 and the heat generation amount is small, so (oil temperature To) − (saturation temperature) Even if Ts) = α is 0 or more, there is a case where two layers are separated at the bottom. Conversely, if the frequency is higher than a predetermined frequency, the stirring effect is large, so that even if α ≦ 0, the dissolution region is obtained. Because there is a possibility. By this frequency correction, the presence or absence of two-layer separation can be grasped more accurately. The signal processing process so far is simplified and shown in FIG.
[0030]
Next, the two-layer separation determination unit 18 receives a signal representing the correction difference αa from the frequency correction unit 17, and when the correction difference αa becomes equal to or less than zero (αa ≦ 0), the refrigerant and the lubrication are performed. It is determined that the oil is separated into two layers in the compressor 5 and a signal indicating that the two layers are separated is output. On the other hand, when the correction value αa exceeds zero (αa> 0), the two-layer separation determination unit 18 determines that the refrigerant and the lubricating oil are not separated into two layers in the compressor 5. , A signal indicating that the two layers are not separated is output.
[0031]
If the two-layer separation determination unit 18 outputs a signal indicating that the two-layer separation is performed, a two-layer separation avoidance operation is performed by issuing an insufficient lubrication warning of the compressor 5. It is possible to prevent friction and seizure of the sliding portion of the compressor due to the above.
[0032]
[Second Embodiment]
Next, FIG. 2 shows a configuration of an air conditioner as a second embodiment. The second embodiment includes an indoor heat exchanger 21, an outdoor heat exchanger 22, a throttle expansion unit 23, a four-way switching valve 24, a compressor 25, and an accumulator 26 that are connected by refrigerant lines. . This air conditioner uses, as a lubricating oil, an oil having a specific gravity smaller than that of the refrigerant used in the air conditioner and having no compatibility with the refrigerant.
[0033]
A suction pressure sensor 27 is attached to the suction pipe to the accumulator 26. A discharge pressure sensor 30 and a discharge pipe temperature sensor 31 are attached to the discharge pipe 28. Further, the second embodiment includes an input value selection unit 32 connected to the suction pressure sensor 27 and the discharge pressure sensor 30 and an oil temperature correction calculation unit 33 connected to the discharge pipe temperature sensor 31. ing.
[0034]
The input value selection unit 32 is connected to a saturation temperature calculation unit 34, and the saturation temperature calculation unit 34 is connected to a comparison unit 35. On the other hand, the oil temperature correction calculation unit 33 is connected to the comparison unit 35. The comparison unit 35 is connected to a frequency correction unit 36, and the frequency correction unit 36 is connected to a two-layer separation determination unit 37.
[0035]
An operation in which the air conditioner having the above configuration determines the two-layer separation in the compressor 25 based on the signals from the suction pressure sensor 27, the discharge pressure sensor 30, and the discharge pipe temperature sensor 31 will be described.
[0036]
First, the input value selection unit 32 receives a signal Ss representing the suction pressure Ps in the suction pipe from the suction pressure sensor 27 and receives a signal Sd representing the discharge pressure Pd in the discharge pipe from the discharge pressure sensor 30. As shown in the lower part of FIG. 2, when the compressor 25 is a high-pressure dome type, the input value selection unit 32 selects a signal Sd representing the discharge pressure Pd during both cooling and heating, and this The signal Sd is output to the saturation temperature calculation unit 34. On the other hand, when the compressor 25 is a low-pressure dome type, the input value selection unit 32 selects a signal Ss representing the suction pressure Ps during both cooling and heating, and sends this signal Ss to the saturation temperature calculation unit 34. Output.
[0037]
Next, when the saturation temperature calculation unit 34 receives the signal Sd representing the discharge pressure Pd, the saturation temperature Ts of the refrigerant in the compressor 25 is calculated from the discharge pressure Pd using the saturation pressure conversion equation for discharge pressure. calculate. When the saturation temperature calculation unit 34 receives the signal Ss representing the suction pressure Ps, the saturation temperature calculation unit 34 calculates the saturation temperature Ts of the refrigerant in the compressor 25 from the suction pressure Ps using the saturation pressure conversion equation for suction pressure. To do.
[0038]
On the other hand, the oil temperature correction calculation unit 33 receives the signal St output from the discharge pipe temperature sensor 31, corrects the temperature Td of the discharge pipe represented by the signal St, and sets the oil temperature To in the compressor 25. calculate.
[0039]
Next, the comparison unit 35 receives the signal representing the saturation temperature Ts from the saturation temperature calculation unit 34 and the signal representing the oil temperature To from the oil temperature correction calculation unit 33, and receives the saturation temperature Ts and the oil temperature To. , And subtract the saturation temperature Ts from the oil temperature To to calculate the difference α = (oil temperature To) − (saturation temperature Ts).
[0040]
Next, the frequency correction unit 36 receives a signal representing the driving frequency of the compressor 25, adds a correction value Δ to the difference α in accordance with the driving frequency, and sets the corrected difference αa = (α + Δ). calculate. The relationship between the correction value Δ and the drive frequency is directly proportional, and is 0 ° C. when the drive frequency is 60 Hz, as shown in FIG. The signal processing process so far is simplified and shown in FIG.
[0041]
Next, the two-layer determination unit 38 receives a signal representing the correction difference αa from the frequency correction unit 36, and when the correction difference αa becomes equal to or less than zero (αa ≦ 0), the refrigerant, the lubricating oil, Are separated into two layers in the compressor 25, and a signal indicating that the two layers are separated is output. On the other hand, when the correction value αa exceeds zero (αa> 0), the two-layer separation determination unit 37 indicates that the refrigerant and the lubricating oil are not separated into two layers in the compressor 25. Is output.
[0042]
When the two-layer separation determination unit 37 outputs a signal indicating that the two-layer separation is performed, if an insufficient lubrication alarm is issued and the two-layer separation avoidance operation is performed, sliding due to liquid refrigerant lubrication is performed. Partial friction and seizure can be prevented in advance.
[0043]
[Third embodiment]
Next, FIG. 3 shows a configuration of an air conditioner as a third embodiment. This air conditioner includes an indoor heat exchanger 51, an outdoor heat exchanger 52, a throttle expansion unit 53, a four-way switching valve 54, a compressor 55, and an accumulator 56, which are connected by refrigerant lines. In this air conditioner, oil having a specific gravity smaller than that of the refrigerant used in the air conditioner and having no compatibility with the refrigerant is used as the lubricating oil.
[0044]
The air conditioner also includes an outside air temperature sensor 57 that detects the outside air temperature. The air conditioner also includes a start / stop circuit 58 and a two-layer separation detection circuit 60. The two-layer separation detection circuit 60 includes a signal Sout representing the outside air temperature Tout from the outside air temperature sensor 57, a signal Sss representing the start / stop time tss from the start / stop circuit 58, and a signal Sn representing the number of start / stop times n. It is designed to be entered.
[0045]
The start / stop circuit 58 does not count this on / off operation as start / stop when the compressor 55 is stopped after being continuously operated for 5 minutes or more. In addition, when the compressor 55 has been continuously operated for 10 minutes or more, the start / stop circuit 58 returns the start / stop count to zero and starts a new count. The reason is that the refrigerant has been discharged from the compressor 55 in the state of continuous operation for 10 minutes or more.
[0046]
As shown in FIG. 5, the two-layer separation detection circuit 60 detects the refrigerant and lubricating oil in the compressor 55 when the number of starts / stops n of the compressor 55 exceeds the number of determinations Nj determined by the outside air temperature tout. Are separated into two layers, and it is determined that this separation surface exceeds the oil filler opening in the compressor 55.
[0047]
The two-layer separation detection circuit 60 of the air conditioner configured as described above receives the signal Sout from the outside air temperature sensor 57 and detects the outside air temperature Tout. The two-layer separation detection circuit 60 receives the signals Sss and Sn from the start / stop circuit 58, and the number n of start / stop in which the compressor 55 is turned off is determined by the outside air temperature tout. When the predetermined number of determinations Nj is reached, it is determined that the refrigerant and the lubricating oil in the compressor 55 are separated into two layers, and that this separation surface is immediately before exceeding the oil supply port in the compressor 55.
[0048]
Specifically, when the outside air temperature is −2 ° C., the start / stop circuit 58 counts the number of starts / stops n according to the start / stop pattern in which the compressor 55 is turned on / off, as shown in FIG. As the number of starts / stops n increases to 1, 2,..., The oil concentration (wt%) at the fuel filler port decreases. When the number of start / stop times n is 3, the two-layer separation detection circuit 60 receives a signal Sn indicating that the number of start / stop times n = 3 from the start / stop circuit 58, and the refrigerant in the compressor 55 The lubricating oil is separated into two layers, and it is determined that this separation surface is immediately before exceeding the oil supply port in the compressor 55. If the two-layer separation detection circuit 60 outputs an under-lubrication warning signal when performing this determination and performs the two-layer separation avoidance operation, the sliding portion friction and seizure of the compressor due to poor lubrication will occur in advance. Can be prevented.
[0049]
【The invention's effect】
As is clear from the above, in the refrigerator of the invention of claim 1, the two-layer separation determination means compares the oil temperature detected by the oil temperature detection means with the saturation temperature of the refrigerant detected by the refrigerant saturation temperature detection means. To do. When the difference α between the oil temperature and the saturation temperature α = (the oil temperature−the saturation temperature) becomes equal to or less than zero (α ≦ 0), the discrimination means determines that the refrigerant and the lubricating oil are It is determined that the compressor is separated into two layers.
[0050]
Therefore, according to this invention, the presence or absence of the two-layer separation in the compressor can be determined. Also, if the discriminating means determines that the two-layer separation has occurred and warns the lack of lubrication of the compressor and performs the two-layer separation avoidance operation, the sliding portion will be worn or seized in advance. Can be prevented.
[0051]
Further, in the refrigerator of the invention of claim 1, the two-layer separation determining means is configured such that when the operating frequency of the compressor is a predetermined value, the difference α is less than or equal to zero (α ≦ 0). Then, it is determined that the refrigerant and the lubricating oil are separated into two layers in the compressor. In addition, when the operating frequency of the compressor becomes higher than the predetermined value, the determination means increases the value of the difference α by an amount corresponding to the increase, and becomes zero or less (α ≦ 0). It is determined that the refrigerant and the lubricating oil are separated into two layers in the compressor. In addition, when the operating frequency of the compressor becomes lower than the predetermined value, the determination means has a value obtained by reducing the difference α by an amount equal to or less than zero (α ≦ 0). It is determined that the refrigerant and the lubricating oil are separated into two layers in the compressor.
[0052]
When the operating frequency of the compressor increases, it becomes difficult to separate the two layers even if the difference α is the same value. On the other hand, when the operating frequency of the compressor decreases, the two layers are separated even if the difference α is the same value. It becomes easy. Therefore, as in the first aspect of the invention, when the operating frequency of the compressor is increased or decreased with respect to a predetermined value, the determination means increases or decreases the value α which is the determination reference value, whereby the two-layer separation in the compressor is performed. Judgment can be made more accurately.
[0053]
According to a second aspect of the present invention, the two-layer separation determining means is configured to compress the compression when the number of start / stops when the compressor is turned off from the on state reaches a predetermined number of times determined by the outside air temperature. It is determined that the refrigerant and the lubricating oil in the machine are separated into two layers, and this separation surface is just before the oil filler opening in the compressor.
[0054]
Therefore, according to the present invention, it is possible to determine the presence or absence of two-layer separation in the compressor. In addition, when the determination means determines that the two-layer separation surface is just before the oil filler opening, a warning of insufficient lubrication is issued and the two-layer separation avoidance operation is performed. Burn-in can be prevented in advance.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the configuration of an air conditioner as a first embodiment of a refrigerator according to the present invention.
FIG. 2 is a block diagram showing a configuration of an air conditioner as a second embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of an air conditioner as a third embodiment of the present invention.
FIG. 4 (A) is a diagram showing the flow of signal processing of the present invention, and FIG. 4 (B) is a frequency correction characteristic diagram.
FIG. 5 is a diagram showing that in the third embodiment of the present invention, the number of start / stop times until the two-layer separation surface exceeds the fuel filler opening increases as the outside air temperature increases.
FIG. 6 is a time chart showing how two-layer separation occurs when the outside air temperature is −2 ° C. and the oil concentration at the oil filler port gradually decreases as the compressor starts and stops.
FIG. 7 (A) is a two-layer separation diagram showing a two-layer separation zone with respect to temperature and refrigerant fraction, and FIG. 7 (B) is a schematic diagram showing a two-layer separation state in a compressor. .
FIG. 8 is a solubility diagram in which the saturation temperature of the refrigerant in the compressor is indicated by a broken line and the oil temperature is indicated by a solid line.
[Explanation of symbols]
1, 21, 51 ... indoor heat exchanger, 2, 22, 52 ... outdoor heat exchanger,
3, 23, 53 ... throttle expansion part, 4, 24, 54 ... four-way switching valve,
5, 25, 55 ... compressor, 6, 26, 56 ... accumulator,
7 ... 1st temperature sensor, 8 ... 2nd temperature sensor,
10, 32 ... Input value selection unit, 11 ... Pipe pressure loss correction calculation unit,
12, 35 ... comparison unit, 13 ... discharge pipe, 15 ... third temperature sensor,
16, 33 ... Oil temperature correction calculation unit, 17, 36 ... Frequency correction unit,
18, 37 ... two-layer separation determination unit, 27 ... suction pressure sensor,
30 ... Discharge pressure sensor, 31 ... Discharge pipe temperature sensor, 34 ... Saturation temperature calculator,
57 ... Outside air temperature sensor, 58 ... Start / stop circuit, 60 ... Two-layer separation detection circuit.

Claims (2)

In a refrigerator that uses oil having a specific gravity smaller than that of the refrigerant and substantially not compatible with the refrigerant as a lubricating oil for the compressor (5, 25),
Oil temperature detecting means (15, 16, 31, 33) for detecting the temperature of oil in the compressor (5, 25);
Refrigerant saturation temperature detecting means (7, 8, 10, 11, 27, 30, 32, 34) for detecting the saturation temperature of the refrigerant determined by the pressure in the compressor (5, 25);
The oil temperature detected by the oil temperature detecting means (15, 16, 31, 33) and the refrigerant detected by the refrigerant saturation temperature detecting means (7, 8, 10, 11, 27, 30, 32, 34). When the difference between the oil temperature and the saturation temperature is α = (the oil temperature−the saturation temperature) is less than or equal to zero (α ≦ 0), the refrigerant and the lubricating oil are compared. There example Bei the two-layer separation determining means (12,18,35,37) and for determining to be separated into two layers in the compressor (5,25),
The two-layer separation determining means (12, 18, 35, 37),
When the compressor is operating frequency of (5, 25) is a predetermined value, when said difference alpha becomes zero or less (alpha ≦ 0), the refrigerant and the lubricating oil and is the compressor (5, 25 ) within two layers,
When the operating frequency of the compressor ( 5 , 25 ) becomes higher than the predetermined value, a value ( αa ) obtained by increasing the difference α by the increased amount is less than or equal to zero ( α ≦ 0 ) The refrigerant and the lubricating oil are separated into two layers in the compressor ( 5 , 25 ) ,
When the operating frequency of the compressor ( 5 , 25 ) becomes lower than the predetermined value, a value (α a ) obtained by reducing the difference α by the amount of the decrease is less than or equal to zero ( α ≦ 0 ). when it is a refrigerator in which the refrigerant and the lubricating oil and is characterized in that it determined to be separated into two layers in the compressor (5, 25). In a refrigerator that uses an incompatible oil having a specific gravity smaller than that of the refrigerant and substantially not compatible with the refrigerant as a lubricating oil for the compressor,
An outside air temperature sensor (57) for detecting the outside air temperature;
A start / stop circuit that counts the number of starts / stops when the compressor (55) is turned off from an on state of less than 5 minutes when the compressor is turned on and off repeatedly at startup. 58),
A signal (Sout) representing the outside air temperature from the outside temperature sensor (57) and a signal (Sn) representing the number of starts / stops from the start / stop circuit (58) are input to start / stop the compressor (55). When the number of times reaches the predetermined number of times determined by the outside air temperature, the refrigerant in the compressor and the lubricating oil are separated into two layers, and this separation surface immediately before exceeding the oil filler opening in the compressor A refrigerator having a two-layer separation determining means (60) for determining that

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