ELECTRIC COMPRESSOR

Description

This application claims priority to Japanese Patent Application No. 2024-155473 filed on Sep. 10, 2024, the entire disclosure of which is incorporated herein by reference.

The present disclosure relates to an electric compressor.

BACKGROUND ART

Japanese Patent Application Publication No. 2009-192090 discloses a refrigeration cycle device. The refrigeration cycle device includes a compressor as an electric compressor, a condenser, a pressure control valve, an evaporator, and an accumulator. The refrigeration cycle device includes a refrigerant state estimation means and a discharge capacity control means. The compressor compresses the refrigerant and discharges it to the condenser. The condenser dissipates the heat from the refrigerant discharged from the compressor. The pressure control valve reduces the pressure of the refrigerant, which has released the heat in the condenser, causing it to expand. The evaporator evaporates the refrigerant that has been depressurized and expanded by the pressure control valve. The accumulator separates a liquid refrigerant from the refrigerant flowed out from the evaporator. The refrigerant from which the liquid refrigerant is separated by the accumulator is reintroduced into and compressed by the compressor.

The refrigerant state estimation means estimates the dryness of the refrigerant to be drawn into the compressor. The refrigerant state estimation means estimates the enthalpy of the refrigerant to be drawn into the compressor based on the pressure and the temperature of the refrigerant discharged from the compressor and the temperature of the refrigerant detected in the evaporator. The refrigerant state estimation means estimates the dryness of the refrigerant to be drawn into the compressor based on the enthalpy. The refrigeration cycle device controls the drive of the compressor based on the estimated dryness using the discharge capacity control means.

However, if the refrigerant discharged from the electric compressor contains a liquid refrigerant, it is difficult to estimate the dryness of the refrigerant to be drawn into the electric compressor based on the temperature of the refrigerant. In other words, the electric compressor may continue to operate with the risk of containing a liquid refrigerant in the refrigerant. The electric compressor may fail if the electric compressor compresses the liquid refrigerant.

The present disclosure, which has been made in light of the above-mentioned problem, is directed to providing an electric compressor that is capable of avoiding failures caused by compressing a liquid refrigerant.

SUMMARY

In accordance with an aspect of the present disclosure, there is provided an electric compressor comprising: a compression part configured to compress a refrigerant; an electric motor configured to drive the compression part; and a controller configured to control the electric motor. The controller includes a motor information detector configured to detect a rotational speed and a power consumption of the electric motor. The controller is connected to a suction pressure sensor for detecting a suction pressure of the refrigerant to be drawn into the compression part and a discharge pressure sensor for detecting a discharge pressure of the refrigerant discharged from the compression part. The controller includes: a memory for storing a map; an estimator; and an operation controller. The map indicates a correspondence between the suction pressure, the discharge pressure, the rotational speed, the power consumption, and dryness of the refrigerant to be drawn into the compression part. The estimator is configured to estimate the dryness of the refrigerant based on the map using the rotational speed and the power consumption detected by the motor information detector, the suction pressure detected by the suction pressure sensor, and the discharge pressure detected by the discharge pressure sensor. The operation controller is configured to control an operation of the electric motor according to the dryness estimated by the estimator.

Other aspects and advantages of the disclosure will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure, together with objects and advantages thereof, may best be understood by reference to the following description of the embodiments together with the accompanying drawings in which:

FIG. 1 is a side view of a vehicle including a vehicle air conditioner;

FIG. 2 is a view illustrating a refrigeration cycle of the vehicle air conditioner;

FIG. 3 is a sectional view of an electric compressor;

FIG. 4 is a block diagram of a controller; and

FIG. 5 is a flowchart of a control process performed by the controller.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following describes an embodiment of an electric compressor. The electric compressor according to the embodiment is, specifically, a scroll compressor. The scroll compressor is part of a vehicle air conditioner mounted on a vehicle.

FIG. 1 illustrates a vehicle 100 including a vehicle air conditioner 101. The vehicle air conditioner 101 conditions the climate of the passenger compartment of the vehicle 100.

As illustrated in FIG. 2, the vehicle air conditioner 101 includes a refrigeration cycle C. The refrigeration cycle C includes a scroll compressor 10 serving as an electric compressor, a condenser 11, an expansion valve 12, and an evaporator 13. In other words, the scroll compressor 10 is mounted on the vehicle 100 and is included in the vehicle air conditioner 101. The refrigeration cycle C is filled with the refrigerant and sealed. The refrigerant flows inside the refrigeration cycle C. The refrigerant flows through the scroll compressor 10, the condenser 11, the expansion valve 12, and the evaporator 13 in this order. The refrigerant further flows toward the scroll compressor 10 through the evaporator 13. That is, the refrigerant circulates through the refrigeration cycle C.

Specifically, the gaseous refrigerant at high temperature and high pressure flows into the condenser 11 from the scroll compressor 10. The condenser 11 is configured to condense the refrigerant. The condenser 11 dissipates the heat from the refrigerant to the surroundings of the condenser 11 to condense the refrigerant. More specifically, the condenser 11 condenses the gaseous refrigerant at high temperature and high pressure into the liquid refrigerant at low temperature and high pressure. That is, the liquid refrigerant at low temperature and high pressure flows out from the condenser 11.

The refrigerant flows from the condenser 11 to the expansion valve 12. More specifically, the liquid refrigerant at low temperature and high pressure flows into the expansion valve 12. The expansion valve 12 is configured to reduce the pressure of the refrigerant. That is, the liquid refrigerant at low temperature and high pressure expands to the liquid refrigerant at low temperature and low pressure through the expansion valve 12.

The refrigerant then flows into the evaporator 13 from the expansion valve 12. More specifically, the liquid refrigerant at low temperature and low pressure flows into the evaporator 13. The evaporator 13 is configured to evaporate the refrigerant. The evaporator 13 absorbs heat from the surroundings of the evaporator 13, and transfers the heat to the refrigerant so as to evaporate the refrigerant. More specifically, the evaporator 13 converts the liquid refrigerant at low temperature and low pressure into the gaseous refrigerant at high temperature and low pressure. The evaporator 13 cools the surroundings of the evaporator 13 through an evaporation process. Then, the refrigerant is drawn into the scroll compressor 10 through the evaporator 13.

As illustrated in FIG. 3, the scroll compressor 10 includes a housing 20, a compression part 30, an electric motor 40 for driving the compression part 30, and a controller 50. The housing 20 accommodates a rotary shaft 21, a support part 22 that supports the rotary shaft 21 via a first bearing 71, the compression part 30, and the electric motor 40. That is, the housing 20 accommodates the compression part 30, the electric motor 40, and the controller 50.

The rotary shaft 21 has, at its one end, an eccentric shaft 21a. The eccentric shaft 21a is located at an eccentric position relative to an axis L1 of the rotary shaft 21 and extends in the direction of the axis L1 of the rotary shaft 21 (i.e. the axial direction of the rotary shaft 21). The rotary shaft 21 is connected to a balance weight 21b via the eccentric shaft 21a.

The housing 20 includes a motor housing 23, a fixed scroll base plate 24, a discharge housing 25, and an inverter cover 26.

The motor housing 23 includes an end wall 23a, a peripheral wall 23b, and a suction port 23c. The motor housing 23 has opposite ends that define the motor housing 23 in the axial direction of the rotary shaft 21, and the end wall 23a forms one of the opposite ends of the motor housing 23. The peripheral wall 23b has a cylindrical shape and extends from the outer peripheral edge of the end wall 23a. The axial direction of the peripheral wall 23b corresponds to the axial direction of the rotary shaft 21.

The rotary shaft 21 is rotatably inserted into the end wall 23a via a second bearing 72. In this embodiment, the one end and the other end of the rotary shaft 21 are supported by the end wall 23a and by the support part 22, respectively.

The suction port 23c is formed in the peripheral wall 23b. In other words, the housing 20 has the suction port 23c. The suction port 23c extends from the outer peripheral surface of the peripheral wall 23b. The suction port 23c is connected to the evaporator 13. The refrigerant, which has flowed out from the evaporator 13, is drawn into the housing 20 through the suction port 23c. A suction pressure sensor 61 is disposed at the suction port 23c. The suction pressure sensor 61 is configured to detect the pressure of the refrigerant to be drawn into the housing 20 through the suction port 23c.

The peripheral wall 23b has opposite ends, and one of the opposite ends is connected to the end wall 23a. The fixed scroll base plate 24 is disposed at the other end of the opposite ends of the peripheral wall 23b. The fixed scroll base plate 24 has opposite surfaces, and a fixed scroll spiral wall 24a extends from one of the opposite surfaces of the fixed scroll base plate 24. The fixed scroll spiral wall 24a extends into the peripheral wall 23b from the fixed scroll base plate 24. The fixed scroll base plate 24 and the fixed scroll spiral wall 24a cooperate to form a fixed scroll 31.

The fixed scroll base plate 24 has a discharge hole 24b. The discharge hole 24b is formed through the fixed scroll base plate 24 in the thickness direction of the fixed scroll base plate 24.

The discharge housing 25 is connected to the other of the opposite surfaces of the fixed scroll base plate 24 via a gasket 27. The gasket 27 seals a gap between the discharge housing 25 and the fixed scroll base plate 24.

The discharge housing 25 has a discharge chamber 25a and a discharge port 25d. That is, the housing 20 has the discharge port 25d.

The discharge chamber 25a is defined by the discharge housing 25 and the fixed scroll base plate 24. The discharge chamber 25a is communicated with the discharge hole 24b. The discharge housing 25 has an outlet 25e at a position facing the fixed scroll base plate 24. The outlet 25e is communicated with the discharge hole 24b through the discharge chamber 25a.

The discharge port 25d is connected to the condenser 11. The refrigerant is discharged from the housing 20 toward the condenser 11 through the discharge port 25d. A discharge pressure sensor 62 is disposed at the discharge port 25d. The discharge pressure sensor 62 is configured to detect the pressure of the refrigerant discharged to the condenser 11 through the discharge port 25d.

The compression part 30 of the scroll compressor 10 compresses the refrigerant drawn through the suction port 23c. The compression part 30 is disposed in a part of the motor housing 23 adjacent to the fixed scroll base plate 24 in the axial direction of the rotary shaft 21. The compression part 30 includes the fixed scroll 31, an orbiting scroll 32, and a compression chamber 30a.

The orbiting scroll 32 faces the fixed scroll 31. The orbiting scroll 32 includes an orbiting scroll base plate 32a facing the fixed scroll base plate 24 and an orbiting scroll spiral wall 32b extending from the orbiting scroll base plate 32a. The orbiting scroll spiral wall 32b extends from the orbiting scroll base plate 32a toward the fixed scroll base plate 24. The fixed scroll 31 and the orbiting scroll 32 are arranged so that the fixed scroll spiral wall 24a meshes with the orbiting scroll spiral wall 32b.

A thrust plate 28 is disposed between the orbiting scroll base plate 32a and the support part 22.

The orbiting scroll base plate 32a has opposite surfaces, and the orbiting scroll spiral wall 32b extends from one of the opposite surfaces of the orbiting scroll base plate 32a. The balance weight 21b is connected the other of the opposite surfaces of the orbiting scroll base plate 32a via a third bearing 73. The orbiting scroll base plate 32a is supported by the eccentric shaft 21a via a bushing of the balance weight 21b and the third bearing 73 so that the orbiting scroll base plate 32a rotates relative to the eccentric shaft 21a.

The other surface of the orbiting scroll base plate 32a faces the thrust plate 28, and has four ring members 33. Each of the ring members 33 receives an anti-rotation pin 22a that protrudes from the support part 22 and penetrates through the thrust plate 28.

The fixed scroll spiral wall 24a meshes with the orbiting scroll spiral wall 32b so that the compression chamber 30a is formed between the fixed scroll 31 and the orbiting scroll 32. The compression chamber 30a is communicated with the discharge hole 24b.

The electric motor 40 is accommodated in the motor housing 23. The electric motor 40 is disposed in a space (i.e., a motor chamber 23e) defined by the support part 22, the end wall 23a, and the peripheral wall 23b of the motor housing 23. The motor chamber 23e is a part of a space in the peripheral wall 23b and adjacent to the end wall 23a. The motor chamber 23e is connected to the compression chamber 30a via a cutout 23f formed in the inner peripheral surface of the peripheral wall 23b. The refrigerant drawn from the suction port 23c flows through the motor chamber 23e, the cutout 23f, the compression chamber 30a, and the discharge chamber 25a in this order, and is discharged from the discharge port 25d.

The electric motor 40 includes a stator 41 and a rotor 42 disposed inside the stator 41. The rotary shaft 21 is inserted through the rotor 42. The rotor 42 rotates together with the rotary shaft 21. The stator 41 surrounds the rotor 42.

The electric motor 40 is configured to rotate the rotor 42 to rotate the rotary shaft 21. The rotation of the rotary shaft 21 is transmitted to the orbiting scroll 32 via the eccentric shaft 21a, the bushing of the balance weight 21b, and the third bearing 73. The anti-rotation pin 22a comes into contact with the inner peripheral surface of the ring member 33 to prevent the rotation of the orbiting scroll 32 on its axis. Accordingly, the orbiting scroll 32 orbits relative to the fixed scroll 31. The orbiting scroll 32 orbits with the orbiting scroll spiral wall 32b in contact with the fixed scroll spiral wall 24a. Accordingly, the volume of the compression chamber 30a decreases with the orbital motion of the orbiting scroll 32.

In the scroll compressor 10, the refrigerant drawn into the housing 20 through the suction port 23c is introduced into the outermost peripheral portion of the compression chamber 30a through the motor chamber 23e and the cutout 23f. Then, the refrigerant is compressed in the compression chamber 30a with the orbital motion of the orbiting scroll 32. The refrigerant compressed by the compression part 30 flows through the discharge hole 24b, the discharge chamber 25a, and the outlet 25e, and is discharged from the housing 20 through the discharge port 25d. In such a manner, the compression part 30 of the scroll compressor 10 compresses the refrigerant. The scroll compressor 10 compresses the refrigerant drawn through the suction port 23c by the compression part 30, and discharges the compressed refrigerant from the housing 20 through the discharge port 25d. That is, the refrigerant to be compressed by the compression part 30 is drawn into the housing 20 through the suction port 23c. The refrigerant compressed by the compression part 30 is discharged from the housing 20 through the discharge port 25d. The suction pressure sensor 61 detects the suction pressure of the refrigerant to be drawn into the compression part 30, and the discharge pressure sensor 62 detects the discharge pressure of the refrigerant discharged from the compression part 30. The suction pressure is the pressure of the refrigerant at the suction port 23c. The discharge pressure is the pressure of the refrigerant at the discharge port 25d.

The inverter cover 26 is attached to the end wall 23a. The controller 50 is accommodated in a space defined by the inverter cover 26 and the end wall 23a.

As illustrated in FIG. 4, the controller 50 is connected to the electric motor 40, the suction pressure sensor 61, and the discharge pressure sensor 62. The controller 50 receives a value of the suction pressure detected by the suction pressure sensor 61 and a value of the discharge pressure detected by the discharge pressure sensor 62.

The controller 50 is configured to control the electric motor 40. More specifically, the controller 50 outputs a value of the rotational speed, which serves as a command value, to the electric motor 40 to control the electric motor 40. The controller 50 is supplied with power from a power supply source (not illustrated) disposed outside the housing 20. The controller 50 is driven by the power.

The controller 50 includes a motor information detector 51, a memory 52, an estimator 53, and an operation controller 54. The controller 50 includes a processor (not illustrated). Examples of the processor include a central processing unit (CPU), a graphics processing unit (GPU), and a digital signal processor (DSP). The memory 52 includes random access memory (RAM) and read only memory (ROM). The memory 52 stores program code or instructions that the processor follows to perform operations. The memory 52 includes any available media that may be accessed by general-purpose or dedicated computers. The controller 50 may include a hardware circuit, such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). The controller 50, which is a processing circuit, may include one or more processors that operate according to a computer program, one or more hardware circuits, such as an ASIC or an FPGA, or a combination thereof.

The motor information detector 51 detects the rotational speed and the power consumption of the electric motor 40. For example, the motor information detector 51 is connected to a rotational speed sensor (not illustrated), and detects the rotational speed via the rotational speed sensor. The motor information detector 51 detects the power consumption of the electric motor 40 by calculating the power consumption using the current and the voltage supplied to the electric motor 40 from an inverter device (not illustrated) of the controller 50, for example. The controller 50 acquires values of the rotational speed and the power consumption of the electric motor 40 detected by the motor information detector 51. The rotational speed of the electric motor 40 will be referred to simply as the rotational speed. The power consumption of the electric motor 40 will be referred to simply as power consumption.

While the scroll compressor 10 is operating, the controller 50 receives the values of the suction pressure and the discharge pressure, and acquires the values of the rotational speed and the power consumption. The controller 50 receives the values of the suction pressure and the discharge pressure and acquires the values of the rotational speed and the power consumption continuously. In other words, the values of the suction pressure, the discharge pressure, the rotational speed, and the power consumption may continuously change over time. The controller 50 may receive the values of the suction pressure and the discharge pressure and acquire the values of the rotational speed and the power consumption at regular time intervals. That is, the controller 50 should be configured to acquire the values of the suction pressure, the discharge pressure, the rotational speed, and the power consumption, which may change according to the operating conditions of the scroll compressor 10.

The memory 52 stores a map. The map indicates a correspondence between the suction pressure, the discharge pressure, the rotational speed, the power consumption, and the dryness of the refrigerant to be drawn into the compression part 30. The dryness refers to the weight ratio of the gaseous components in the refrigerant. That is, the refrigerant with lower dryness contains more liquid refrigerant. The map provides a unique dryness of the refrigerant to be drawn into the compression part 30 for each combination of the suction pressure, the discharge pressure, the rotational speed, and the power consumption in the scroll compressor 10. The dryness of the refrigerant to be drawn into the compression part 30 will be referred to simply as dryness.

The map is generated by simulating the operation of the scroll compressor 10 under multiple conditions. Specifically, the map is generated in the following manner. First, the values of the suction pressure, the discharge pressure, the dryness, and the rotational speed are specified. Next, the operation of the scroll compressor 10 is simulated to calculate the value of the power consumption required for achieving the combination of the specified values of the suction pressure, the discharge pressure, the dryness, and the rotational speed. The required power consumption for each combination of the values of the suction pressure, the discharge pressure, the dryness, and the rotational speed is determined by varying the values of the suction pressure, the discharge pressure, the dryness, and the rotational speed. The simulation results are sorted according to the dryness of the refrigerant to generate the map.

The estimator 53 estimates the dryness of the refrigerant to be drawn into the compression part 30 based on the map. The estimator 53 estimates the dryness of the refrigerant based on the map by referring to the values input to the estimator 53. More specifically, the estimator 53 receives the values of the rotational speed and the power consumption detected by the motor information detector 51 and the values of the suction pressure and the discharge pressure respectively detected by the suction pressure sensor 61 and the discharge pressure sensor 62. That is, the estimator 53 estimates the dryness of the refrigerant using the rotational speed and the power consumption detected by the motor information detector 51, the suction pressure detected by the suction pressure sensor 61, and the discharge pressure detected by the discharge pressure sensor 62. More specifically, the estimator 53 uses the values of the suction pressure, the discharge pressure, the rotational speed, and the power consumption to obtain the dryness corresponding to each of these values in the map. The estimator 53 estimates the obtained dryness as the dryness of the refrigerant to be drawn into the scroll compressor 10. The estimator 53 does not estimate the dryness using the temperature of the refrigerant.

The estimator 53 is configured to measure the time elapsed since the electric motor 40 was activated. For example, the controller 50 includes a timer (not illustrated), and the estimator 53 refers to measurement results of the timer. The estimator 53 may refer to measurement results of a timer provided outside the controller 50. The estimator 53 estimates the dryness of the refrigerant after a predetermined time has elapsed since the electric motor 40 was activated. The predetermined time according to the present embodiment is the time until a detection error in the power consumption of the electric motor 40 detected by the motor information detector 51 falls within an acceptable range. The predetermined time according to the present embodiment is set in advance in the controller 50.

The operation controller 54 controls the operation of the electric motor 40 according to the dryness estimated by the estimator 53. More specifically, the operation controller 54 stops the electric motor 40 when the dryness estimated by the estimator 53 is outside a predetermined range. The predetermined range according to the present embodiment is the acceptable dryness range of the refrigerant compressed by the compression part 30. The predetermined range according to the present embodiment is set in advance in the operation controller 54.

The operation controller 54 does not control the operation of the electric motor 40 until the predetermined time has elapsed. In other words, the operation controller 54 controls the operation of the electric motor 40 while the estimator 53 estimates the dryness of the refrigerant.

The following will describe the control of the electric motor 40 performed by the controller 50 with reference to FIGS. 4 and 5.

Upon activation of the vehicle air conditioner 101 illustrated in FIG. 1, the electric motor 40 starts operating and the controller 50 starts control of the electric motor 40.

The controller 50 determines in step S1 whether the predetermined time set in advance has elapsed since the electric motor 40 was activated. When the controller 50 determines that the predetermined time has not elapsed since the electric motor 40 was activated, the controller 50 performs step 1 again.

When the controller 50 determines that the predetermined time has elapsed since the electric motor 40 was activated, the controller 50 performs step 2. Specifically, in step S2, the estimator 53 of the controller 50 estimates the dryness of the refrigerant based on the map using the values of the rotational speed and the power consumption detected by the motor information detector 51 and the values of the suction pressure and the discharge pressure detected by the suction pressure sensor 61 and the discharge pressure sensor 62.

The controller 50 then performs step S3. The controller 50 determines in step S3 whether the estimated dryness is within the predetermined range set in advance. The controller 50 performs step S4 when the estimated dryness is within the predetermined range. The controller 50 determines in step S4 whether the electric motor 40 is stopped. When the electric motor 40 is operating, the process returns from step S4 to step S2, and the controller 50 performs step S2 again. In other words, when the estimated dryness is within the predetermined range, the estimator 53 of the controller 50 estimates the dryness while the electric motor 40 is operating.

When the controller 50 determines that the estimated dryness is outside the predetermined range in step S3, the controller 50 performs step S5. In step S5, the controller 50 controls the operation controller 54 to stop the operation of the electric motor 40. Then, the controller 50 performs step S4. In this case, the controller 50 determines in step S4 that the electric motor 40 is stopped, and ends the control of the electric motor 40.

When a driver of the vehicle 100 stops the vehicle air conditioner 101, the controller 50 stops the operation of the electric motor 40, regardless of which step of steps S1 to S5 in FIG. 5 is being performed.

The following will explain the advantageous effects according to the present embodiment.

• • (1) The estimator 53 of the controller 50 estimates the dryness of the refrigerant to be drawn into the compression part 30 based on the map stored in the memory 52. That is, the estimator 53 estimates the dryness of the refrigerant without using the temperature of the refrigerant discharged from the compression part 30. This allows the estimator 53 to estimate the dryness of the refrigerant to be drawn into the compression part 30 even if the refrigerant contains liquid refrigerant, unlike when the dryness is estimated based on the temperature of the refrigerant discharged from the compression part 30. This therefore allows the scroll compressor 10 to estimate the dryness of the refrigerant to be drawn, even if the discharged refrigerant contains liquid refrigerant. The operation controller 54 of the controller 50 controls the operation of the electric motor 40 according to the dryness estimated. For example, when the estimator 53 of the controller 50 estimates the dryness that may cause the compression part 30 to compress the liquid refrigerant, the operation controller 54 of the controller 50 stops the operation of the electric motor 40. In this way, the scroll compressor 10 avoids failures caused by compressing the liquid refrigerant.
  • (2) The accuracy of the power consumption detected by the motor information detector 51 improves over time from the electric motor 40 is activated until the operation of the electric motor 40 stabilizes. Because the estimator 53 estimates the dryness of the refrigerant after the predetermined time has elapsed since the electric motor 40 was activated, the estimator 53 estimates the dryness more accurately compared to a case where the dryness is estimated immediately after the electric motor 40 is activated. That is, the controller 50 of the scroll compressor 10 controls the electric motor 40 more accurately after the predetermined time has elapsed since the electric motor 40 was activated.
  • (3) If the motor information detector 51 detects the power consumption of the electric motor 40 immediately after the electric motor 40 is activated, the motor information detector 51 may erroneously detect the power consumption of the electric motor 40 and the estimator 53 of the controller 50 therefore may estimate abnormal dryness using the value of the power consumption erroneously detected. However, according to the present embodiment, the estimator 53 of the controller 50 estimates the dryness of the refrigerant after the predetermined time has elapsed since the electric motor 40 was activated. This allows the controller 50 to avoid that the electric motor 40 is stopped according to abnormal dryness. In other words, the operation controller 54 controls the electric motor 40 in the aforementioned manner, so that the scroll compressor 10 avoids unintended stopping of the electric motor 40.
  • (4) In the scroll compressor 10, the operation controller 54 may stop the electric motor 40 when the dryness estimated by the estimator 53 is outside the predetermined range. The predetermined range according to the present embodiment is the acceptable dryness range of the refrigerant compressed by the compression part 30. This allows the scroll compressor 10 to avoid compressing the refrigerant with unintended dryness.
  • (5) For example, the arrangement of the suction pressure sensor 61 and the discharge pressure sensor 62 according to the present embodiment allows the suction pressure sensor 61 and the discharge pressure sensor 62 to more accurately detect the suction pressure and the discharge pressure as compared to an arrangement where the suction pressure sensor 61 and the discharge pressure sensor 62 are away from the suction port 23c and the discharge port 25d.
  • (6) The suction pressure sensor 61 and the discharge pressure sensor 62 are included in the scroll compressor 10. This configuration allows the scroll compressor 10 to estimate the dryness of the refrigerant to be drawn through the suction port 23c without requiring the refrigeration cycle C, which includes the scroll compressor 10, to include another suction pressure sensor 61 and another discharge pressure sensor 62.
  • (7) This configuration eliminates the need for the refrigeration cycle C to include another suction pressure sensor 61 and another discharge pressure sensor 62, thereby enabling miniaturization of the refrigeration cycle C. Accordingly, the scroll compressor 10 according to the present embodiment enables miniaturization of the vehicle air conditioner 101 that includes the scroll compressor 10.

The aforementioned embodiments may be modified as described below. The embodiments may be combined with the following modifications within technically consistent range.

The scroll compressor 10 is not necessarily mounted on the vehicle 100. The scroll compressor 10 is not necessarily included in the vehicle air conditioner 101. For example, the scroll compressor 10 may be included in a stationary air conditioner.

The suction pressure sensor 61 may detect the pressure of the refrigerant downstream of the suction port 23c and upstream of the compression chamber 30a inside the scroll compressor 10. In this configuration, the suction pressure sensor 61 is disposed in a part of the housing 20 upstream of the compression part 30. For example, the suction pressure sensor 61 may detect the pressure of the refrigerant in the motor chamber 23e.

The suction pressure sensor 61 is not necessarily disposed at the suction port 23c. For example, the suction pressure sensor 61 may be disposed downstream of the evaporator 13 and upstream of the suction port 23c in the refrigeration cycle C. That is, the suction pressure sensor 61 should be disposed at a position that allows the suction pressure sensor 61 to detect the pressure of the refrigerant before the refrigerant is compressed by the compression part 30.

The discharge pressure sensor 62 may detect the pressure of the refrigerant upstream of the discharge port 25d and downstream of the compression chamber 30a inside the scroll compressor 10. In this configuration, the discharge pressure sensor 62 is disposed in a part of the housing 20 downstream of the compression part 30. For example, the discharge pressure sensor 62 may detect the pressure of the refrigerant in the discharge chamber 25a.

The discharge pressure sensor 62 is not necessarily disposed at the discharge port 25d. For example, the discharge pressure sensor 62 may be disposed upstream of the condenser 11 and downstream of the discharge port 25d in the refrigeration cycle C. That is, the discharge pressure sensor 62 should be disposed at a position that allows the discharge pressure sensor 62 to detect the pressure of the refrigerant after the refrigerant is compressed by the compression part 30.

The operation controller 54 does not necessarily stop the electric motor 40 when the dryness of the refrigerant estimated by the estimator 53 is outside the predetermined range. For example, when the dryness estimated by the estimator 53 is outside the predetermined range, the operation controller 54 may change the rotational speed of the electric motor 40 so that the estimated dryness falls within the predetermined range.

The estimator 53 may estimate the dryness immediately after the electric motor 40 is activated.

The map may be generated in a way different from the embodiment. For example, the map may be generated by machine learning using the relationship between the suction pressure, the discharge pressure, the rotational speed, the power consumption, and the dryness, which are obtained from simulations, as training data.

The motor information detector 51 is not necessarily connected to the rotational speed sensor. For example, the motor information detector 51 may detect a command value output by the controller 50.

The electric compressor is not limited to the scroll compressor 10. For example, the electric compressor may be a centrifugal compressor. In this case, the compression part 30 includes a plurality of impellers and diffuser flow paths.

Supplementary Note

The following will describe technical ideas of the embodiments and the modifications.

• • 1. The electric compressor is mounted on a vehicle and included in a vehicle air conditioner of the vehicle.
  • 2. The electric compressor includes a housing for accommodating a compression part, an electric motor, and a controller, wherein a suction pressure sensor is disposed in a part of the housing upstream of the compression part, and a discharge pressure sensor is disposed in a part of the housing downstream of the compression part.
  • 3. The electric compressor includes an estimator, wherein the estimator does not estimate dryness using a temperature of a refrigerant.