Expansion valve device

Abstract

Expansion valve device which is arranged in a refrigeration circuit (3) for decompressing and expanding a refrigerant which circulates in the refrigeration circuit, wherein the expansion valve device comprises: a housing (51) which defines a refrigerant passage (51a) through which the refrigerant flows; a valve element (53) which is arranged in the housing in such a way as to change the degree of opening of the refrigerant passage; and an electric drive element (55) comprising a stepper motor for controlling the degree of opening by adjusting the valve element in accordance with a rotation angle of the stepper motor; characterized by a drive control device (10) which drives and controls the stepper motor with a constant current, wherein The drive control device is configured to perform a mode change with a constant current between a first mode in which the opening degree of the refrigerant passage is changed to a first flow range in which the flow rate of the refrigerant flowing through the refrigerant passage is less than or equal to a predetermined value, and a second mode in which the opening degree of the refrigerant passage is changed to a second flow range in which the flow rate of the refrigerant flowing through the refrigerant passage is higher than the predetermined value, and to increase a value (A2) of the constant current during the mode change to be greater than a value (A1) of a constant current when the opening degree of the refrigerant passage is changed to the first mode; the drive control unit is set up to determine whether there is a mode change in the refrigeration circuit (S220); The drive control device is set up to determine whether a predetermined time (T) has elapsed since a last increase in the current value (S260) when it is determined that there is a mode change in the refrigeration circuit; and The drive control device is set up to increase the value (A2) of the constant current during the mode change to be greater than the value (A1) of the constant current in the first mode (S270) when it is determined that there is a mode change in the refrigeration circuit, and when it is determined that the predetermined time (T) since the last increase in the current value has elapsed.

Description

Reference to the affected registration

[0001] This invention or disclosure is based on the Japanese patent application JP 2011 - 208 295 A, which was filed on September 24, 2011, the disclosure of which is incorporated here in its entirety by reference. Technical field

[0002] The present invention relates to an expansion valve device according to the preamble of claim 1.

[0003] Patent document 1 describes an electric valve (electric expansion valve) used to control the flow rate of a refrigerant. The electric valve has a valve element that opens or closes a control slot of a fluid passage using a stepper motor. The electric valve incorporates a reduction gear, and the rotational output of the stepper motor's rotor is transmitted to a screw mechanism that moves the valve element through the reduction gear. This achieves a powerful valve control force and a high-resolution valve opening characteristic.

[0004] It is possible to ensure high output accuracy and high accuracy in flow rate control with the electric expansion valve, from a low-flow control range to a high-flow control range. However, when, for example, the valve opening degree is changed from the low-flow control range to the high-flow control range, or vice versa, it takes time to move the valve element.This means that when switching between a mode in which the valve opening degree is changed within the control range of a low flow rate and a mode in which the valve opening degree is changed within the control range of a high flow rate, it takes a long time to achieve a set valve opening degree. Patent document 2 shows a generic expansion valve device according to the preamble of claim 1. State-of-the-art document - patent document Patent document 1: JP 2006 - 226 369 A Patent document 2: DE 100 35 666 A1 Summary of the invention

[0005] It is an object of the present invention to provide an expansion valve device that makes it possible to shorten the time required to reach a target valve opening degree in a case where a mode change is performed between a mode in which the valve opening degree is changed within a control range of low flow rates and a mode in which the valve opening degree is changed within a control range of high flow rates, and to avoid functional errors. This object is achieved with an expansion valve device having the features of claim 1. Advantageous embodiments of the present invention are the subject of the dependent claims.

[0006] According to an example of the present invention, an expansion valve device, arranged in a refrigeration circuit for decompressing and expanding a refrigerant circulating through the circuit, comprises a housing, a valve element, an electrical actuator, and an actuator control device. The housing defines a refrigerant passage through which the refrigerant circulates. The valve element is arranged in the housing to change the degree of opening of the refrigerant passage. The electrical actuator includes a stepper motor to control the degree of opening of the refrigerant passage by adjusting the valve element in accordance with a rotation angle of the stepper motor. The actuator control device drives and controls the stepper motor with a constant current.The drive control device performs a mode change with a constant current between a first mode, in which the opening degree of the refrigerant passage is changed to a first flow range in which the flow rate of the refrigerant flowing through the refrigerant passage is less than or equal to a predetermined value, and a second mode, in which the opening degree of the refrigerant passage is changed to a second flow range in which the flow rate of the refrigerant flowing through the refrigerant passage is greater than the predetermined value, and increases the value of the constant current during the mode change to be greater than the value of a constant current used when the opening degree of the refrigerant passage is changed to the first mode.

[0007] Accordingly, the drive control device can drive the stepper motor with a constant current in a stable manner, even if a voltage supplied by a power source is varied.Furthermore, when the mode change is performed between the first mode, in which the opening degree of the refrigerant passage is changed to the first flow range, in which the flow rate of the refrigerant flowing through the refrigerant passage is lower than or equal to the predetermined value, and the second mode, in which the opening degree of the refrigerant passage is changed to the second flow range, in which the flow rate of the refrigerant flowing through the refrigerant passage is higher than the predetermined value, the current value of the constant current drive is increased to be greater than the value used when the opening degree of the refrigerant passage is changed to the first mode.In this way, the torque generated by the stepper motor is increased to adjust the valve element, allowing the valve opening degree to be changed quickly.

[0008] Therefore, if the mode change is performed between a mode in which the refrigerant passage opening degree is changed to a control range of low flow rate and a mode in which the refrigerant passage opening degree is changed to a control range of high flow rate, the time required to reach the set valve opening degree can be reduced.

[0009] Preferably, the drive control device has a delay mechanism that slows down the rotation of the stepper motor, and the valve element is adjusted by the rotation of the stepper motor via the delay mechanism. The expansion valve device equipped with the delay mechanism, which slows the rotation of the stepper motor, can achieve high accuracy in flow control; however, it takes a considerable amount of time to move the valve element in response to a change in the valve opening degree. It is therefore very effective to apply the present invention to an expansion valve device equipped with the delay mechanism.

[0010] Preferably, the drive control device prevents an increase in the current value itself at a time of a mode change if the temperature of the drive control device is higher than a predetermined value or if the value of a physical quantity relating to the temperature is higher than a predetermined threshold.

[0011] If the temperature becomes too high, the drive control device may malfunction. Therefore, if the temperature of a component of the drive control device exceeds a predetermined value, or if the value of the physical quantity related to temperature is higher than a predetermined threshold, the current value is prevented from increasing, even during a mode change, thus preventing the temperature of the drive control device from rising. The drive control device is therefore prevented from malfunctioning.

[0012] Preferably, the first mode is a decompression-expansion mode in which the refrigerant is decompressed and expanded in the first flow region when it is necessary to decompress the refrigerant flowing through the refrigerant passage, and the second mode is a fully open mode in which the valve element causes the degree of opening of the refrigerant passage to be at a maximum, such that the flow rate of the refrigerant flowing through the refrigerant passage is maximized in the second flow region when it is not necessary to decompress the refrigerant flowing through the refrigerant passage.

[0013] Accordingly, during a decompression-expansion mode, in which the refrigerant is decompressed and expanded at a low flow rate (where the flow rate through the refrigerant passage is less than or equal to a predetermined value), the refrigerant flow rate is controlled with relatively sufficient accuracy by adjusting the valve element. Furthermore, when switching between the decompression-expansion mode and the fully open mode (where the refrigerant passage opening through the valve element is maximized), the mode change can be executed quickly.

[0014] Preferably, the first mode is a first decompression-expansion mode in which the refrigerant is decompressed and expanded in the first flow region, and the second mode is a second decompression-expansion mode in which the refrigerant is decompressed and expanded in the second flow region, and the drive control device increases the value of the constant current at the time of a mode change to be greater than both the value of a constant current used when the opening degree is changed to the first mode and the value of a constant current used when the opening degree is changed to the second mode.

[0015] During a decompression-expansion mode, in which the refrigerant is decompressed and expanded in the low-flow range where the flow rate of the refrigerant passing through the refrigerant passage is lower than or equal to the predetermined value, and during a decompression-expansion mode, in which the refrigerant is decompressed and expanded in the high-flow range where the flow rate of the refrigerant passing through the refrigerant passage exceeds the predetermined value, the refrigerant flow rate is controlled with a comparatively sufficient accuracy by adjusting the valve element.Furthermore, if a mode change is performed between the decompression-expansion mode within the range of a low flow rate and the decompression-expansion mode within the range of a high flow rate, the mode change can be carried out quickly. Brief description of the drawings Fig. Figure 1 is a schematic view representing an expansion valve device according to one embodiment; Fig. Figure 2 is a schematic view depicting a vehicle air conditioning system which includes the expansion valve device; Fig. Figure 3 is a diagram that shows a relationship between a valve opening degree and a refrigerant flow rate in each operating mode of a refrigeration cycle; Fig. Figure 4 is a flowchart illustrating valve opening control by a drive control device of the expansion valve assembly; and Fig. Figure 5 is a diagram that shows a relationship between a rotational speed or rotational speed and a generated torque of a motor of the expansion valve device. embodiment for implementing the invention

[0016] The Fig. Figure 1 is a cross-sectional view (partially including a block diagram) showing a variable throttle valve 50 for heating, corresponding to an expansion valve device according to one embodiment, and an air conditioning control device 10, which controls the variable throttle valve 50. Fig. 2 represented an air conditioning device for a vehicle which uses the variable throttle valve 50.

[0017] As it is in the Fig. As shown in Figure 2, the air conditioning system includes an air conditioning unit 1, which provides air conditioning for the passenger compartment of the vehicle. Air conditioning components (actuators) in the air conditioning unit 1 are controlled by the air conditioning control unit 10 (ECU). The air conditioning unit 1 comprises a refrigeration circuit 3, which includes a line 2, a centrifugal fan, an evaporator 27, and a gas cooler 22. The line 2 defines an air outlet that introduces conditioned air into the passenger compartment. The fan generates an airflow in the line 2 towards the passenger compartment. The evaporator 27 cools the air flowing through the line 2. The gas cooler 22 reheats the air that has passed through the evaporator 27.

[0018] The duct 2 is located on the front side of the passenger compartment in the vehicle. An interior air inlet 11 and an exterior air inlet 12 are defined upstream of the duct 2 in the direction of airflow. The interior air inlet 11 draws air into the interior of the passenger compartment (hereinafter referred to as interior air). The exterior air inlet 12 draws outside air from the passenger compartment (hereinafter referred to as outside air). An interior / exterior air switching flap 4 is rotatably mounted on the inner sides of the interior air inlet 11 and the exterior air inlet 12. The interior / exterior air switching flap 4 is driven by an actuator 13, such as a servo motor, and changes the air intake mode between an exterior air intake mode (FRS) and an interior air recirculation mode (REC).

[0019] A plurality of air outlets (not shown) is defined downstream of line 2 in the direction of airflow. The air outlets include at least one defroster outlet (DEF), one front outlet (FRONT), and one foot outlet (FUSS). The defroster outlet primarily blows warm air toward an inner surface of the vehicle's windshield. The front outlet primarily blows cold air toward the upper body (head and chest) of an occupant. The foot outlet primarily blows warm air toward the lower body (feet) of an occupant. The air outlets are selectively opened or closed by a plurality of mode-changing flaps (not shown).The mode change flaps are driven by an actuator 14, such as a servo motor, thereby switching the air outlet mode (MODE) under a front mode (FRONT), a two-level mode (B / L), a foot mode (FOOT), a foot defroster mode (F / D) and a defroster mode (DEF).

[0020] The centrifugal blower comprises a centrifugal fan 5 and a blower motor 16, which rotates the fan 5. The fan 5 is rotatably mounted in a spiral housing, which is integrally formed on the upstream side of the line 2 in the direction of airflow. The speed of the motor 16 is varied based on a supply voltage to the blower motor 16 (blower control voltage, blower level), which is applied by a blower drive circuit (not shown), thus controlling the amount of air directed into the passenger compartment.

[0021] Refrigeration circuit 3 comprises a compressor 21, a gas cooler 22, a first decompressor, an external heat exchanger 24, an internal heat exchanger, a second decompressor, an evaporator 27, a receiver / storage tank 28, and a refrigerant pipe connecting them in a ring-shaped configuration. The compressor 21 is rotated by an internal drive motor (not shown). The compressor 21 is an electric refrigerant compressor that compresses refrigerant drawn in by the evaporator 27 to a high temperature and high pressure equal to or greater than a critical pressure, for example, and then discharges the refrigerant. The compressor 21 is switched on (ON) when electrical current is supplied and is stopped (OFF) when the electrical current is stopped.The speed of compressor 1 is controlled by a converter 20 such that compressor 21 has a target speed which is calculated by the control unit ECU 10.

[0022] The gas cooler 22 is arranged in line 2 downstream of the evaporator 27 in the direction of airflow. The gas cooler 22 is a heat exchanger for heating the air passing through it with the gaseous refrigerant flowing from the compressor 21. Air mixing flaps (A / M flaps) 6, 7 are rotatably mounted on an air inlet and an air outlet of the gas cooler 22. The flaps 6, 7 control the temperature of the air blown into the passenger compartment by controlling the amount of air passing through the gas cooler 22 and the amount of air bypassing it. The A / M flaps 6, 7 are actuated by an actuator 15, such as a servo motor.

[0023] The first decompressor is formed by the variable throttle valve 50, into which the gaseous refrigerant flows from the gas cooler 22. The variable throttle valve 50 is a first decompression device that decompresses the refrigerant flowing out of the gas cooler 22 based on the valve opening degree and can correspond to an electric expansion valve for heating (EVH). The valve opening degree is electrically controlled by the control unit ECU 10. Furthermore, the variable throttle valve 50 can be set to a fully open mode by the control unit ECU 10, so that the valve opening degree of the variable throttle valve 50 can be fully open.

[0024] The external heat exchanger 24 is located in a position that allows it to easily receive airflow while the vehicle is in motion, outside of line 2 (for example, at the front of the vehicle's engine compartment). Heat exchange takes place between the refrigerant flowing through the interior of the heat exchanger 24 and the outside air in the passenger compartment (exterior air), which is circulated by an electric fan (not shown). The external heat exchanger 24 functions as a heat sink, absorbing heat from the outside air in a heating mode or a dehumidifying mode (dehumidifying-heating mode), and as a radiator, radiating heat to the outside air in a cooling mode or a dehumidifying mode.

[0025] The internal heat exchanger is a refrigerant-to-refrigerant heat exchanger that superheats the refrigerant drawn into an inlet port of the compressor 21. Heat exchange takes place between the high-temperature refrigerant flowing out of the outlet of the external heat exchanger 24 and the low-temperature refrigerant flowing out of the outlet of the storage tank or collector 28. The internal heat exchanger has a two-layer heat exchange structure in which a surface of a low-temperature side heat exchanger 29 is in close contact with a surface of a high-temperature side heat exchanger 25 to facilitate heat exchange.

[0026] The second compressor has a variable throttle valve 26 for cooling and a bypass pipe 33. The refrigerant flows into the throttle valve 26 from the heat exchanger 25 on the high-temperature side of the inner heat exchanger. Refrigerant flowing out of the heat exchanger 25 on the high-temperature side of the inner heat exchanger is routed to the receiver 28 bypassing the throttle valve 26 and the evaporator 27 via the pipe 33. The variable throttle valve 26 is a secondary decompression device that decompresses the refrigerant flowing out of the heat exchanger 25 on the high-temperature side of the inner heat exchanger based on the valve opening degree. The variable throttle valve 26 is an electric expansion valve for cooling (EVC), and the valve opening degree is electrically controlled by the control unit ECU 10.An electromagnetic open / close valve 34 (hereinafter referred to as the electromagnetic valve for heating) is arranged in the pipe 33. The valve 34 opens when electricity is supplied (ON) and closes when the electricity supply is stopped (OFF).

[0027] The evaporator 27 is an air-to-refrigerant heat exchanger (heat absorber). The refrigerant, which has been decompressed by the throttle valve 26, is evaporated by heat exchange with the air, which is supplied by the fan 5. Heat from the air is absorbed by the evaporator 27. The evaporator 27 supplies the gaseous refrigerant to the low-temperature side heat exchanger 29 from the inner heat exchanger and to the compressor 21 via the receiver 28. The receiver 28 is a gas-liquid separator which has a storage chamber for temporarily storing the refrigerant flowing from the evaporator 27.

[0028] A switching section of a circulation circuit of the refrigeration circuit 3 switches the operating mode of the refrigeration circuit 3, i.e., the refrigerant circulation path in the refrigeration circuit 3 is switched between a circulation circuit for the cooling mode (cooling circuit), a circulation circuit for the heating mode (heating circuit), and a circulation circuit for the dehumidification mode or the dehumidification-heating mode (dehumidification circuit). In the present embodiment, the variable throttle valve 50 and the electromagnetic valve 34 can correspond to a switching section of a circulation circuit.

[0029] More precisely, when the variable throttle valve 50 is in the fully open mode for heating and the electromagnetic valve 34 is closed for heating, the operating mode of refrigeration circuit 3 is set to the cooling circuit (circulation circuit for cooling mode). Furthermore, when valve 50 is in a decompression mode, in which the refrigerant is decompressed and expanded to achieve a low flow rate, and valve 34 is open, the operating mode of refrigeration circuit 3 is set to the heating circuit (circulation circuit for heating mode). Additionally, when valve 50 is in the decompression mode and valve 34 is closed, the operating mode of refrigeration circuit 3 is set to the dehumidification circuit (circulation circuit for dehumidification mode).

[0030] Refrigeration cycle 3 of this configuration uses a refrigerant whose main component is carbon dioxide (CO2), which has a low critical temperature. Refrigeration cycle 3 is a supercritical vapor / compression heat pump cycle. The refrigerant discharged from the compressor 21 outlet is at a high pressure equal to or higher than the critical pressure. In this supercritical vapor / compression heat pump cycle, the refrigerant temperature at the gas cooler 22 inlet (refrigerant inlet temperature) is raised to approximately 120°C by increasing the refrigerant pressure on the high-pressure side. This means that the temperature of the refrigerant discharged from the compressor 21 outlet is raised to approximately 120°C.Additionally, the refrigerant flowing into the gas cooler 22 does not condense, even if the refrigerant radiates heat into the gas cooler 22, because the refrigerant is pressurized by the compressor 21 to have a pressure equal to or higher than the critical pressure.

[0031] The control unit ECU 10 comprises a known microcomputer, which includes, for example, a CPU that executes a control and calculation process, a memory (ROM, RAM) that stores a number of programs and data, an I / O port (input / output port), and a timer function. When the vehicle's ignition switch is turned on (IG-AN), electricity is supplied to the control unit ECU 10. The control unit ECU 10 electrically controls each actuator (such as the servo motor 13-15, the blower motor 16, the variable throttle valve 26, 50, the electromagnetic valve 34, and the converter 20) of the climate control unit 1 based on an input of an actuation signal from an air conditioning control panel (not shown), sensor signals input from various sensors, and a control program stored in the memory.

[0032] The climate control panel features a temperature setting switch, an air conditioning switch (A / C switch), an air intake setting switch (FRS / REC switch), an air outlet setting switch (MODE switch), a defroster switch (DEF switch), an airflow switch, an automatic switch (AUTO switch), a power switch (OFF switch), and similar controls. The air conditioning switch (A / C switch) is a cooling or dehumidifying switch that activates cooling or dehumidification for the passenger compartment. The A / C switch is a setting for cooling / dehumidifying, selecting the cooling or dehumidifying mode among the operating modes of refrigeration circuit 3. The compressor 21 of refrigeration circuit 3 is forcibly activated by turning on the A / C switch and forcibly stopped by turning off the A / C switch.

[0033] The DEF switch is a switch for setting a DEF mode, which instructs the air outlet mode to be set to DEF mode, or defroster mode. The DEF switch is also an anti-fog switch, which removes or prevents windshield fogging. Furthermore, the DEF switch is a dehumidification mode selection section, which instructs the operating mode of refrigeration circuit 3 to be set to dehumidification mode. The dehumidification mode selection section sets the dehumidification mode, which is either a dehumidification priority mode or an outlet air temperature priority mode. Alternatively, the dehumidification mode selection section can be a separate anti-fog sensor from the DEF switch, which detects windshield fogging.The dehumidification mode selection section can be a dehumidification switch that simply instructs dehumidification in the passenger compartment without setting the air outlet mode to DEF mode when the switch is turned on. The dehumidification mode selection section can also be an anti-fog switch that simply instructs the prevention of windshield fogging without setting the air outlet mode to DEF mode when the switch is turned on.

[0034] The AUTO switch is a switch that automatically sets the operating mode of refrigeration circuit 3 to cooling mode, heating mode, or dehumidification mode based on at least one target outlet temperature (TAO). The AUTO switch is an automatic control switch that instructs each actuator of air conditioning unit 1 to control automatically. For example, if the MODE change switch or the air volume control switch is operated, the air conditioning control for switching the air outlet mode or controlling the fan motor is automatically overridden.

[0035] An outlet pressure sensor 40 detects the outlet pressure (control diagram) of the refrigerant being discharged from an outlet port of the compressor 21. An outlet temperature sensor 41 detects the outlet temperature (TD) of the refrigerant being discharged from the outlet port of the compressor 21. A first refrigerant temperature sensor 42 detects the temperature (TCO) of a refrigerant being discharged from the outlet of the gas cooler 22. A second refrigerant temperature sensor 43 detects the temperature (THO) of a refrigerant flowing out of the outlet of the outdoor heat exchanger 24. Sensor signals output by sensors 40, 41, 42, and 43 undergo analog-to-digital conversion at an input circuit (the analog-to-digital conversion, which is implemented in the Fig. The figure 2, which is not shown, refers to an input processor 102 in the Fig. 1), and the converted signal is input into the microcomputer. The outlet pressure sensor 40 is a high-pressure sensor that detects the high pressure of the refrigeration circuit 3. The outlet temperature sensor 41 is also a refrigerant detector that detects the inlet temperature of the refrigerant flowing into the inlet section of the gas cooler 22.

[0036] An outside air temperature sensor 44 detects the temperature of the outside air (TAM), which is the air temperature outside the passenger compartment. A temperature sensor 45 (which may correspond to a dehumidification capacity detector of the present invention) detects an air temperature (TE: hereinafter referred to as the post-evaporator temperature) just downstream of the evaporator 27. An inside air temperature sensor 46 detects the temperature of the inside air (TR), which is the air temperature inside the passenger compartment. A solar sensor 47 detects the amount of solar radiation (TS) entering the passenger compartment. A temperature sensor 48 (which may correspond to a heating capacity detector of the present invention) detects an air temperature (TGC: hereinafter referred to as the post-gas cooler temperature) just downstream of the gas cooler 22.Sensor signals output by sensors 44, 45, 46, 47 and 48 undergo analog / digital conversion at the analog / digital conversion circuit, and the converted signal is input into the microcomputer.

[0037] The following is a brief description of one operating mode of the air conditioning system.

[0038] For example, when the ignition switch is turned to the ON position and electricity is supplied to the control unit ECU 10, the control unit ECU 10 selects the operating mode of the refrigeration circuit 3 based on the handling signal transmitted from each switch (not shown) on the air conditioning control panel, the sensor signal transmitted by the various sensors, and the control program stored in memory. Thus, each actuator (the servo motor 13-15, the blower motor 16, the variable throttle valve 26, 50, the electromagnetic valve 34, and the converter 20) of the air conditioning unit 1 is electrically controlled.

[0039] For example, when the AUTO switch is activated to perform automatic climate control, the ECU 10 control unit receives the sensor signals from the various sensors and the handling signal from the climate control console. These signals are required to control each climate control element (actuator) in climate control unit 1. Next, the target outlet temperature (TAO) of the conditioned air blown into the passenger compartment is calculated based on a formula that is pre-stored in memory.

[0040] Next, a compressor operation assessment is performed to determine whether compressor 21 is switched on or off, for example, based on the air conditioning switch (A / C switch). If the compressor operation assessment indicates that compressor 21 is switched on based on the previously calculated target outlet temperature (TAO), an operating mode assessment is performed to determine the operating mode of refrigeration circuit 3.

[0041] During the operating mode assessment, the target outlet temperature (TAO) is compared to a first predefined value α (for example, 45°C) and a second predefined value β (for example, 15°C). If TAO ≥ α, the heating cycle (heating mode) is selected as the operating mode of refrigeration circuit 3. If TAO ≤ β, the cooling cycle (cooling mode) is selected as the operating mode of refrigeration circuit 3. If β < TAO < α, the dehumidification cycle (dehumidification mode) is selected as the operating mode of refrigeration circuit 3.

[0042] After the operating mode of the refrigeration circuit 3 is selected, a supply voltage applied to the blower motor 16 (blower control voltage, blower stage), an opening degree of the flap 4, which changes the air intake mode (between the indoor air mode and the outdoor air mode), an opening degree of the mode switching flap, which changes the air outlet mode, and an opening degree of the air mixing flap or A / M flap 6, 7 (A / M opening degree) are determined, and the actuators are controlled to drive the blower and the flaps.

[0043] The operating mode of refrigeration circuit 3 is set. The operating state of compressor 21 (speed, etc.), the opening degree of variable throttle valve 50, 26, and the open / close state of electromagnetic valve 34 are set and controlled in such a way that the circuit efficiency of refrigeration circuit 3 is maximized in each operating mode.

[0044] When cooling mode is selected as the operating mode of refrigeration circuit 3, the variable throttle valve 50 is fully open, and the electromagnetic valve 34 is closed. The refrigerant discharged from the compressor 21 outlet circulates in the following sequence: gas cooler 22, fully open valve 50, external heat exchanger 24, high-temperature side heat exchanger 25, valve 26, evaporator 27, receiver 28, low-temperature side heat exchanger 29, and compressor 21 (as indicated by the direction of an empty arrow). Fig. Figure 2 shows the circulation loop for the cooling mode (cooling circuit).

[0045] At this point, the opening degree of the air mixing flap 6, 7 is controlled to be fully closed (MAX-COOL). The high-temperature, high-pressure refrigerant discharged by the compressor 21 does not radiate heat as it passes through the gas cooler 22. Therefore, the air cooled in the evaporator 27 flows through line 2 to bypass the gas cooler 22. The air is then blown, for example, from the front outlet into the passenger compartment, thus cooling the passenger compartment to a desired temperature (set temperature).Furthermore, heat is exchanged in the internal heat exchanger between the high-temperature, high-pressure refrigerant flowing through heat exchanger 25 on the high-temperature side from the external heat exchanger 24, and the low-temperature, low-pressure refrigerant flowing through heat exchanger 29 on the low-temperature side from the collector 28. This cools the high-temperature, high-pressure refrigerant flowing into the evaporator 27. As a result, the evaporator enthalpy increases, thus improving the efficiency of refrigeration cycle 3 by saving electricity.

[0046] When heating mode is selected as the operating mode of refrigeration circuit 3, the variable throttle valve 50 is in decompression mode, and the electromagnetic valve 34 is open. The refrigerant discharged from the compressor 21 outlet circulates in the following sequence: gas cooler 22, valve 50, outdoor heat exchanger 24, high-temperature side heat exchanger 25, valve 34, receiver 28, low-temperature side heat exchanger 29, and compressor 21 (as indicated by the direction of a black arrow in the diagram). Fig. Figure 2 shows the circulation circuit for the heating mode (heating circuit). At this point, valve 26 can be completely closed.

[0047] At this point, the opening degree of the air mixing flap 6, 7 is controlled to be fully open (MAX-HOT). The high-temperature, high-pressure refrigerant discharged by the compressor 21 radiates heat to the air in line 2 as it passes through the gas cooler 22. The air is blown into the passenger compartment from the footwell outlet, thus heating the passenger compartment to a desired temperature (set temperature). No heat exchange takes place in the interior heat exchanger, as the low-temperature, low-pressure refrigerant bypasses each of the heat exchangers 25, 29.

[0048] When dehumidification mode is selected as the operating mode of refrigeration circuit 3, the variable throttle valve 50 is in decompression mode, and the electromagnetic valve 34 is closed. The refrigerant discharged from the compressor 21 outlet circulates in the following sequence: gas cooler 22, valve 50, outdoor heat exchanger 24, high-temperature side heat exchanger 25, valve 26, evaporator 27, receiver 28, low-temperature side heat exchanger 29, and compressor 21 (as indicated by the direction of a hatched arrow). Fig. Figure 2 shows the circulation cycle for the dehumidification mode (dehumidification cycle).

[0049] At this point, air is cooled and dehumidified in the evaporator 27, and then reheated in the gas cooler 22. The air is blown into the passenger compartment, for example, from the DEF outlet or the FUSS outlet. The passenger compartment is dehumidified and heated to a desired temperature (set temperature) and to prevent or eliminate windshield fogging. The outlet pressure of the refrigerant discharged by the compressor 21 and the refrigerant pressure of the outside heat exchanger 24 are variable by adjusting the throttling degree of the variable throttle valve 50, 26.Thus, the degree of throttling is controlled in such a way that the heating capacity of the gas cooler 22 (a temperature of air flowing out of the gas cooler or into the passenger compartment) or the dehumidification capacity of the evaporator 27 (a temperature of air flowing out of the evaporator) has a target value.

[0050] If the throttling degree is controlled in such a way that the outlet pressure of the refrigerant discharged by the compressor 21 and the refrigerant pressure of the external heat exchanger 24 become low (the opening degree of valve 50: small, the opening degree of valve 26: large), the external heat exchanger 24 functions (operates as) even more precisely as a heat sink, so that the amount of heat radiated by the gas cooler 22 increases. At this point, for example, the outlet temperature of the conditioned air blown into the passenger compartment is therefore comparatively high.

[0051] If, in contrast, the throttling degree is controlled in such a way that the outlet pressure of the refrigerant discharged by the compressor 21 and the refrigerant pressure of the external heat exchanger 24 become high (the opening degree of valve 50: large, the opening degree of valve 26: small), the external heat exchanger 24 functions (is operated as) a cooler, so that the amount of heat radiated by the gas cooler 22 decreases. The outlet temperature of the air-conditioned air blown into the passenger compartment is therefore comparatively low.

[0052] Next, the variable throttle valve 50 for heating and the air conditioning control unit 10, which controls the valve 50, will be explained.

[0053] As it is in the Fig. As shown in Figure 1, the variable throttle valve 50 comprises a housing 51, a seat component 52, a valve element 53, a spring 54, a motor 55, a plate component 56, a ring component 57, an O-ring 58 and a delay mechanism 59.

[0054] The housing 51, for example, is made of a metallic material and has an approximately L-shaped refrigerant passage 51a through which the refrigerant circulates. Within the housing 51, the cylindrical seat component 52, which is also made of a metallic material, is arranged on the curved part of the refrigerant passage 51a such that an inner space of the seat component 52 defines a portion of the refrigerant passage 51a. The seat component 52 has an upper surface, and an inner circumference of the upper surface defines a seat 52a.

[0055] The valve element 53, for example, is made of a metallic material and is arranged in the refrigerant passage 51a of the housing 51. A main part of the valve element 53 has an approximately frustoconical shape, and an outer circumference of a lower end face of the valve element 53 defines a seat part which is inserted into or separated from the seat 52a of the seat component 52. The valve element 53 has a shaft 53a which extends from the main part in the Fig. 2 extends upwards. The shaft 53a is arranged in a through-hole portion of the housing 51, which extends in the axial direction of the shaft 53a, and an upper end of the shaft 53a is arranged to protrude from the housing 51.

[0056] The motor 55 is a stepper motor and is located on the upper side of the housing 51. The motor 55 has a housing 553, which has an approximate dome shape, consisting of a cylindrical part and a hemispherical part that closes the upper end of the cylindrical part. An annular stator 551 is located on the outer circumference of the cylindrical part of the housing 553, and a rotor 552 is located inside the cylindrical part.

[0057] A lower end of the cylindrical part of the housing 553 has a flange section that extends outwards in the radial direction. The O-ring 58, which acts as a sealing element, is inserted between the flange section and the housing 51. The metallic plate component 56 is screwed to the housing 51 and presses the flange section onto the housing 51 through the ring component 57, which is positioned above the flange section of the housing 553. Therefore, a seal between the housing 51 and the housing 553 of the motor 55 can be achieved over the entire circumference.

[0058] The stator 551 is located on the upper side of the plate component 56 and has a two-phase structure, consisting of a coil 551A of an A-phase and a coil 551B of a B-phase. The motor 55 is what is known as a two-phase stepper motor.

[0059] The rotor 552, which is arranged in the housing 553, is made of a magnetic material. The rotor 552 has an approximately columnar main part 552a and a cylindrical magnet 552b. A portion of the main part 552a is recessed in a ring-shaped depression on both the upper and lower surfaces. The cylindrical magnet 552b is made of a permanent magnet and is arranged on the outer circumferential surface of the main part 552a. The cylindrical magnet 552b is magnetized in the same direction of rotation as the rotor 552.

[0060] A concave section is defined in the main part 552a of the rotor 552 and is recessed upwards from the central part of the lower surface. The upper end of the shaft 53a of the valve element 53 is attached to a top surface portion of the concave section.

[0061] A threaded section is formed on the inner circumferential surface of the concave portion of the main part 552a of the rotor 552. On the other side, a cylindrical external threaded section 51b is attached to the housing 51 and projects upwards. An external threaded section is formed on the outer circumferential surface of the external threaded section 51b.

[0062] The delay mechanism 59, which is constructed by combining several gears, is arranged between the inner circumferential surface of the concave section of the main part 552a of the rotor 552 and the outer circumferential surface of the externally threaded part 51b. The delay mechanism 59 can, for example, be made from a planetary gear mechanism comprising a sun gear and a planet gear. Alternatively, the delay mechanism 59 can be constructed by combining a plurality of spur gears.

[0063] The deceleration mechanism 59 has an input gear which engages thread-wise with the screw part formed on the inner circumferential surface of the concave section of the main part 552a of the rotor 552, and an output gear which engages thread-wise with the external thread formed in the outer circumferential surface of the external thread part 51b, and slows down the rotation of the rotor 552 and transmits it to the external thread part 51b.

[0064] As a result, a rotation of the rotor 552 adjusts the rotor 552 in the axial direction (a direction from top to bottom in the drawing). Since the delay mechanism 59 is inserted between the rotor 552 and the externally threaded part 51b, the magnitude of an adjustment of the rotor 552 in the axial direction is comparatively small in relation to the magnitude of a rotation of the rotor 552.

[0065] When the rotor 552 is rotated and adjusted in the axial direction, the valve element 53, which is attached to the main part 552a of the rotor 552, is also adjusted to change the degree of opening between the valve element 53 and the seat 52a.

[0066] A construction defined by the motor 55, the delay mechanism 59 and the external threaded part 51b, which engages thread-wise with the rotor 552 via the delay mechanism 59, can correspond to an electrical drive element which has a stepper motor and a control of an opening degree of a refrigerant passage by adjusting a valve element in accordance with a rotation angle of the stepper motor.

[0067] As is clearly stated in the Fig. As shown in Figure 1, the shaft 53a of the valve element 53 has a stepped section. The spring 54 is inserted between the stepped section and the top surface of the main part 552a of the rotor 552. In this way, when the rotor 552 is moved downwards after the valve element 53 is placed on the seat 52a, the spring 54 is compressed, thus preventing excessive load from being applied to a seat section defined between the valve element 53 and the seat 52a.

[0068] Furthermore, the rotor 552 is prevented from exhibiting excessive rotational adjustment due to a pin component 51c, which protrudes from the housing 51, and a pin component 552c, which protrudes from the rotor 552, which come into contact with each other.

[0069] As it is in the Fig. As shown in Figure 1, the control unit ECU 10 comprises an air conditioning control unit 101, an input processor 102, and a drive unit 103. The input processor 102 processes a signal input from each switch or sensor, and the processed signal is sent to the air conditioning control unit 101. The drive unit 103 outputs value information, determined by the control unit 101, as an electrical signal to control each actuator (the servo motor 13-15, the blower motor 16, the throttle valve 26, the electromagnetic valve 34, or the transducer 20).

[0070] The control unit ECU 10 further comprises a stepper motor controller 111, a drive unit 113, and an input processor 112. The stepper motor controller 111 receives a command regarding the opening degree of the valve 50, which is determined by the air conditioning controller 101, and determines drive information (for example, a current value) for the motor 55 based on the command. More precisely, the drive direction (direction of rotation) of the motor 55 from the valve 50 and the number of steps (number of pulses) for the drive of the motor 55 from the valve 50 are set by the stepper motor controller 111. The drive unit 113 energizes the coil 551A of an A-phase and the coil 551B of a B-phase of the stator 551 via PWM control based on the drive information of the valve 50, which is determined by the stepper motor controller 111.The current values ​​of coil 551A of an A-phase and coil 551B of a B-phase are entered into the input processor 112, and the input processor 112 performs feedback control with respect to the stepper drive control 111.

[0071] The stepper drive controller 111 receives the command regarding the opening degree of the valve 50, which is determined by the air conditioning controller 101, and determines the drive information, such as the drive direction (direction of rotation) of the motor 55 of the valve 50 and the number of steps (number of pulses), based on the input command and the current valve opening degree. Furthermore, the stepper drive controller 111 can determine the current value by detecting a change in the operating circuit mode and can issue the instruction to the drive unit 113.

[0072] The stepper drive controller 111, the input processor 112 and the drive unit 113 can define a drive control device which drives and controls the stepper motor.

[0073] When cooling mode is selected as the operating mode of refrigeration circuit 3, the air conditioning controller 101 sends a valve opening instruction to the stepper drive controller 111. This valve opening instruction directs the variable throttle valve 50 to be fully open. When heating mode or dehumidification mode (dehumidification-heating mode) is selected as the operating mode of refrigeration circuit 3, the air conditioning controller 101 sends a valve opening instruction to the stepper drive controller 111. This valve opening instruction directs the variable throttle valve 50 to decompress and expand the refrigerant in a manner that improves the operating efficiency of refrigeration circuit 3 for achieving the desired air conditioning performance.

[0074] The Fig. Figure 3 is a diagram illustrating the relationship between the valve opening degree and the refrigerant flow rate in each of the cooling, dehumidifying / heating, and heating modes. The variable throttle valve 50 has a control range of valve opening, indicated by the solid line and the black dot. In heating mode, a suitable valve opening is controlled within a low flow rate range, where the refrigerant flow rate is comparatively low. In dehumidifying / heating mode, a suitable valve opening is controlled within an intermediate flow rate range. In cooling mode, the maximum valve opening is controlled to achieve the maximum flow rate within a high flow rate range.

[0075] Next, the opening degree control of the valve 50, which is carried out by the drive control device of the present embodiment, consisting of the stepper drive controller 111, the input processor 112 and the drive unit 113, will be explained. Fig. Figure 4 is a flowchart or process diagram that illustrates the overview of the valve opening control by the drive control device.

[0076] As it is in the Fig. As shown in Figure 4, the drive control unit inputs the drive direction (opening direction) and the number of steps (the number of pulses) of the motor 55 from the valve 50, which are determined by the air conditioning control 101, and information regarding a change in the operating circuit mode (S210).

[0077] Here, the valve opening instruction for valve 50 is entered, and the drive information, such as the drive direction (opening direction) and the number of steps (the number of pulses) of motor 55 from valve 50, is determined based on the entered valve opening instruction and the current valve opening. Furthermore, the change in the operating cycle mode can be determined, for example, based on the characteristic value, which is specified in the Fig. 3 is shown.

[0078] Next, it is determined whether there is a change in the operating cycle based on S210 (S220). If S220 indicates that there is no change in the operating cycle, it is determined whether the number of steps (the number of pulses) to be executed by motor 55 is greater than or equal to a predetermined value (S230).

[0079] If S230 detects that the number of steps is equal to or greater than the predetermined value (less than the predetermined value), a current value A1 (predetermined current value at normal time) is set as the current value of a constant current drive (S240). The drive is then operated at a constant current by outputting the current value A1, such that the motor operates at normal speed R1 (S250). The drive control unit then returns to S210.

[0080] If S220 determines that there is no change in the operating cycle, and if S230 determines that the number of steps is greater than or equal to the predetermined value (i.e., in the case where it is determined that the degree of change concerning the valve opening is large, i.e., greater than or equal to the predetermined value, although there is no change in the operating cycle), the drive control device proceeds to S260.

[0081] S260 checks whether a predetermined time T has elapsed since the last increase in current. The elapsed time since the last increase in current is the time immediately following the execution of S270, S280, and S290, which are described later. If S260 determines that the predetermined time T has not yet elapsed since the last increase in current, the drive control unit proceeds with S240.

[0082] When the current value of the constant-current drive is increased by executing S270, S280, and S290, the temperature of the drive control unit (more precisely, its component parts) increases. The predetermined time T, which is an evaluation value in S260, is a threshold used to determine whether the temperature of the drive control unit's component parts has decreased after the temperature increase, which is accompanied by the increase in current value.

[0083] Therefore, if it is determined at S260 that the predetermined time T has not elapsed since the last increase in current, it is determined that the temperature of the drive control unit's components has not been sufficiently reduced. If the current is subsequently increased, there is a possibility that the drive control unit's components will reach an excessively high temperature and cause a functional fault, thus making a further increase in current impermissible.

[0084] If it is determined in S260 that the predetermined time T has elapsed since the last increase in the current value, a current value A2 (predetermined current value at a time of high rotational speed), which is greater than the current value A1, is set as a constant current drive current value (S270), since it is assumed that the temperature of the component parts of the drive control device has decreased sufficiently. Then, a target speed R2 of motor 55 is calculated based on the instruction value of the number of pulses entered in S210 and a predetermined allow time for the cycle change (S280).

[0085] After S280 has been executed, a constant current drive with current value A2 is executed to achieve the target speed R2 of motor 55 (S290). Afterwards, the drive control unit returns to S210.

[0086] Accordingly, the drive control device of this embodiment, which consists of the stepper drive control 111, the input processor 112 and the drive unit 113 of the control unit ECU 10, increases the current value used for the constant current drive of the motor 55 when a mode change is performed between three modes, i.e., the heating mode of the refrigeration circuit 3, in which the amount of refrigerant flowing through the refrigerant passage 51a of the valve 50 is less than or equal to a first predetermined value; the dehumidifying-heating mode of the refrigeration circuit 3, in which the amount of refrigerant flowing through the refrigerant passage 51a exceeds the first predetermined value and is less than or equal to a second predetermined value; and the cooling mode of the refrigeration circuit 3, in which the amount of refrigerant flowing through the refrigerant passage 51a exceeds the first predetermined value and is less than or equal to a second predetermined value.the maximum in a flow range which exceeds the second predetermined value, then the value of a constant current which is used when the flow rate control is executed within the heating mode, and the value of a constant current which is used when the flow rate control is executed within the dehumidification heating mode.

[0087] If a voltage supplied by the power source is changed, the drive control device can accordingly drive the motor 55 in a stable manner with a constant current.

[0088] Furthermore, when a mode change is performed between the heating mode, in which the valve opening is changed within the low-flow range lower than or equal to the first predetermined value for decompressing and expanding the refrigerant, and the dehumidifying-heating mode, in which the valve opening is changed within the intermediate-flow range exceeding the first predetermined value for decompressing and expanding the refrigerant, the constant current value of the actuator from motor 55 is increased by the constant current value used when the valve opening degree is changed in each of the modes. Thus, when a mode is changed between the heating mode and the dehumidifying-heating mode, the torque generated by motor 55 is increased to adjust the valve element 53, allowing the valve opening degree to be changed quickly.

[0089] In this case, a mode in which the valve opening is changed at the time of a heating mode corresponds to a first mode in which the degree of opening of the refrigerant passage within the first flow range is changed, which is lower than or equal to a predetermined value, and a mode in which the valve opening is changed at the time of a dehumidifying heating mode corresponds to a second mode in which the degree of opening of the refrigerant passage within the second flow range is changed, which exceeds the predetermined value.

[0090] Furthermore, when a mode change is performed between the heating mode and the dehumidifying-heating mode, in which the valve opening is changed within a small to medium flow range that is less than or equal to a second predetermined value to decompress and expand the refrigerant, and the cooling mode, in which the valve opening is changed within a large flow range that exceeds the second predetermined value to maximize the valve opening degree, the current value of the constant current drive from motor 55 is increased to the constant current value used when the valve opening degree is changed within the heating mode and the dehumidifying-heating mode.When the mode change is performed between the heating mode and the dehumidifying heating mode, in which the refrigerant is decompressed and expanded, and the cooling mode, in which the refrigerant is not decompressed to the fully open mode, the generated torque of the motor 55 is thus increased to adjust the valve element 53 so that the valve opening degree can be changed quickly.

[0091] In this case, a mode in which the valve opening is changed during a heating mode and a dehumidifying-heating mode corresponds to a first mode in which the degree of refrigerant passage opening is changed within the first flow range, which is lower than or equal to a predetermined value, and a mode in which the valve opening is changed during a cooling mode corresponds to a second mode in which the degree of refrigerant passage opening is changed within the second flow range, which exceeds the predetermined value.

[0092] As it is in the Fig. As shown in Figure 5, if the current value is set to constant, for example A1, and the motor 55, which consists of the stepper motor, is driven with this constant current, a high rotational speed cannot be achieved because the generated torque is reduced in response to the high-speed instruction at the point of a circuit switch. In this embodiment, at the point of a circuit switch requiring a high rotational speed, the current value is increased to A2 in order to increase the generated torque sufficiently to achieve the high rotational speed.

[0093] Therefore, when switching between a mode in which the valve opening degree is changed within a relatively small range of flow control and a mode in which the valve opening degree is changed within a relatively large range of flow control, the time required to reach the set valve opening degree can be reduced. Furthermore, it is not necessary to increase the size of the motor.

[0094] Furthermore, S260 prevents what is in the Fig. As shown in Figure 4, the drive control device increases the current value by executing S240 and S250 itself at the time of a mode change when the time elapsed since the last increase in the current value is short (on the short side) in relation to the predetermined time T, such that a value of a physical quantity relating to the temperature of the component parts of the drive control device is high.

[0095] If the temperature of components of the drive control unit becomes too high, the drive control unit may malfunction. Therefore, if the value of a physical quantity related to the temperature of components of the drive control unit exceeds a threshold, even during a mode change, the current is prevented from increasing, thus limiting the temperature rise of the components. This prevents the drive control unit from malfunctioning. Furthermore, in such a case, although it becomes difficult for the stepper motor to maintain a high speed because the electrical current applied to the motor 55 may be reduced, the drive control unit can improve operating efficiency.

[0096] Furthermore, S280 calculates what is in the Fig. As shown in Figure 4, the drive control unit determines the target speed of the stepper motor from the instruction value of the number of pulses and the switching time of the circuit. At S290, the drive control unit drives the motor by outputting a constant current to achieve the target speed. Therefore, at the time of a circuit switch (at the time of a mode change), the rotation of the stepper motor can be increased to a required degree, thus controlling the generation of heat in the drive control unit.

[0097] Furthermore, in the S230, it allows what is in the Fig. As shown in Figure 4, the drive control device does not cause the stepper motor to exhibit a high speed at S260, S270, S280, and S290, even during a circuit switchover, namely when the rate of change with respect to the valve opening is large, i.e., the number of pulses at the time of the change in the valve opening rate is greater than or equal to a predetermined value, even in the same mode. Therefore, the time required to reach the set valve opening rate cannot be shortened, even during a mode switchover.

[0098] Furthermore, according to the present embodiment, the variable throttle valve 50 for heating is equipped with a delay mechanism 59, which slows down the rotation of the stepper motor, and the valve element 53 is adjusted by the rotation of the stepper motor via the delay mechanism 59. Although high accuracy of flow control can be achieved by the valve 50, which is equipped with the delay mechanism 59 that slows down the rotation of the stepper motor when the stepper motor is only rotating at a normal speed, it can take a considerable amount of time to move the valve element 53 when changing the valve opening degree. It is therefore very efficient to apply the present invention to the valve 50, which is equipped with the delay mechanism 59.

[0099] Although omitted in the explanation of the refrigeration cycle system with reference to the Fig. 2, is, as in the Fig. Figure 1 shows a high-pressure refrigerant pressure sensor 40A arranged to detect the pressure in the refrigerant passage 51a upstream of the valve element 53, i.e., to detect the refrigerant pressure before the valve 50 decompresses the refrigerant in the refrigeration circuit. The stepper motor controller 111 can change the current value of the constant current drive of the motor 55 according to the refrigerant pressure detected by the high-pressure refrigerant pressure sensor 40A. More precisely, if the detected refrigerant pressure becomes high, the current value of the constant current drive can be increased.

[0100] The current value of the constant current actuator is thus increased in accordance with the increase in refrigerant pressure upstream of the valve element 53 in the refrigerant passage 51a. In this case, when a load level increases, the current value of the constant current actuator is increased to increase the maximum generated torque.

[0101] As it is in the Fig.As shown in Figure 1, the high-pressure refrigerant pressure sensor 40A is arranged to detect the pressure in the refrigerant passage 51a upstream of the valve element 53, in order to detect the refrigerant pressure before it is decompressed through the throttle valve 50 in the refrigeration circuit. However, the sensor 40A is not limited to being positioned in the refrigerant pipe directly upstream of the throttle valve 50. For example, the sensor 40A can be arranged in the housing 51 opposite the refrigerant passage 51a upstream of the valve element 53. Furthermore, the outlet pressure sensor 40 can be used together as the high-pressure refrigerant pressure sensor.

[0102] The current value of the constant current actuator can be increased based on an increase in the pressure differential between the upstream and downstream sides of the valve element 53 in the refrigerant passage 51a. Alternatively, the constant current value can be controlled based on sensor information transmitted by three or more sensors.

[0103] Although a detailed explanation has been omitted, the variable throttle valve 26 for cooling can have the same construction as the variable throttle valve 50 for heating. Therefore, the variable throttle valve 26 for cooling and the variable throttle valve 50 for heating can be used together or connected.

[0104] The present invention or disclosure is not limited to the above embodiment and can be carried out with modifications without deviating from the scope of the present invention.

[0105] In the above embodiment, when a mode change is performed between the heating mode, in which the valve opening is changed within the low flow range to less than or equal to the first predetermined value for decompressing and expanding the refrigerant, and the dehumidifying-heating mode, in which the valve opening is changed within the intermediate flow range, which exceeds the first predetermined value for decompressing and expanding the refrigerant, the current value of the constant current drive from the motor 55 is increased by the current value used when the valve opening is changed in each of the modes (when the valve opening is changed within a flow range to less than or equal to the first predetermined value and when the valve opening is changed within a flow range that exceeds the first predetermined value).However, the present invention is not limited to this.

[0106] For example, if the current value in the heating mode, in which the valve opening is changed within the flow range to be lower than or equal to the first predetermined value, differs from the current value in the dehumidification-heating mode, in which the valve opening is changed within the flow range that exceeds the first predetermined value, then all that is necessary is to increase the current value at the time of a mode change by at least the current value in the heating mode, in which the flow rate control is performed within the range of a low flow.

[0107] Specifically, when a mode change is performed between a first mode in which the valve opening within the low flow range is changed to less than or equal to the first predetermined value for decompressing and expanding the refrigerant, and a second mode in which the valve opening within the intermediate flow range is changed to exceed the first predetermined value for decompressing and expanding the refrigerant, all that is necessary is to increase the current value of the constant current actuator to the same extent as the current value used to change the degree of refrigerant passage opening in the first mode.

[0108] Furthermore, in the above embodiment, the drive control device prevents an increase in current value even during a mode change if the elapsed time since the last increase in current value is shorter (short time) than the predetermined time T, thus ensuring that the temperature of component parts of the drive control device remains high. That is, the elapsed time corresponds to a value of a physical quantity relating to the temperature of component parts of the drive control device; however, the present invention is not limited to this.

[0109] The increase in current can be prevented even during a mode switch if a different value of a physical quantity, related to the temperature of component parts of the drive control device, is different from the elapsed time, such that the temperature of component parts exceeds a predefined threshold. Furthermore, the temperature of component parts can be directly measured, and the increase in current can be prevented if the measured temperature exceeds a threshold, even during a mode switch.

[0110] Furthermore, in the above embodiment, although an explanation regarding the stepper drive system of the stepper motor has been omitted, the stepper motor can have a full-step drive or a micro-step drive. Moreover, depending on the required resolution, the full-step drive and the micro-step drive can be combined.

[0111] The full-step drive is a drive method in which a tooth (i.e., a magnetic pole of the cylindrical magnet 552b) of the rotor 552 is moved from a position opposite a tooth (for example, a magnetic pole that is magnetized by each phase coil) of the stator 551 to a position opposite the next tooth of the stator 551, by one step. The microstepping drive is a drive method in which a tooth of the rotor 552 is moved stepwise from a position opposite a tooth of the stator 551 to a position opposite the next tooth of the stator 551, by several steps. That is, in the microstepping drive, the drive angle of one step of the full-step drive is divided into several steps (such that it is possible to stop the tooth of the rotor 552 between two teeth of the stator 551).

[0112] Furthermore, in the above embodiment, although the variable throttle valve 50 is equipped with the delay mechanism 59, which slows down the rotation of the stepper motor, and the valve element 53 is adjusted by the rotation of the stepper motor via the delay mechanism 59, the present invention is not limited thereto. The present invention can be efficiently applied to an expansion valve assembly that is not equipped with a delay mechanism.

[0113] Motor 55 can be a different type of stepper motor, with multiple phases than the two-phase stepper motor. For example, Motor 55 can be a five-phase stepper motor.

[0114] Refrigeration cycle 3 can be a steam / compression type heat pump cycle in which the pressure on the high-pressure side is equal to or lower than the critical pressure, unlike the supercritical steam / compression type heat pump cycle.

[0115] The variable throttle valve 50, which corresponds to the expansion valve device, and the drive control device, which drives and controls the variable throttle valve 50, can be applied to a stationary type refrigeration circuit, unlike the refrigeration circuit for the vehicle air conditioning system.

Claims

[1] Expansion valve device arranged in a refrigeration circuit (3) for decompressing and expanding a refrigerant circulating in the refrigeration circuit, the expansion valve device comprising: a housing (51) which defines a refrigerant passage (51a) through which the refrigerant flows; a valve element (53) which is arranged in the housing in such a way as to change the degree of opening of the refrigerant passage; and an electric drive element (55) which has a stepper motor such that the degree of opening is controlled by adjusting the valve element in accordance with a rotation angle of the stepper motor; characterized by a drive control device (10) which drives and controls the stepper motor with a constant current, wherein The drive control device is configured to perform a mode change with a constant current between a first mode in which the opening degree of the refrigerant passage is changed to a first flow range in which the flow rate of the refrigerant flowing through the refrigerant passage is less than or equal to a predetermined value, and a second mode in which the opening degree of the refrigerant passage is changed to a second flow range in which the flow rate of the refrigerant flowing through the refrigerant passage is higher than the predetermined value, and to increase a value (A2) of the constant current during the mode change to be greater than a value (A1) of a constant current when the opening degree of the refrigerant passage is changed to the first mode; the drive control unit is set up to determine whether there is a mode change in the refrigeration circuit (S220); The drive control device is set up to determine whether a predetermined time (T) has elapsed since a last increase in the current value (S260) when it is determined that there is a mode change in the refrigeration circuit; and The drive control device is set up to increase the value (A2) of the constant current during the mode change to be greater than the value (A1) of the constant current in the first mode (S270) when it is determined that there is a mode change in the refrigeration circuit, and when it is determined that the predetermined time (T) since the last increase in the current value has elapsed. [2] Expansion valve device according to claim 1, wherein the drive control device has a delay mechanism (59) which slows down the rotation of the stepper motor, and the valve element is adjusted by the rotation of the stepper motor through the delay mechanism. [3] Expansion valve device according to claim 1 or 2, wherein the actuator control device prevents an increase in the value of the constant current even during a mode change if the temperature of the actuator control device is higher than a predetermined value or if the value of a physical quantity relating to the temperature is higher than a predetermined threshold. [4] Expansion valve device according to one of claims 1 to 3, wherein the first mode is a decompression-expansion mode in which the refrigerant is decompressed and expanded in the first flow region when it is necessary to decompress the refrigerant flowing through the refrigerant passage, and the second mode is a fully open mode in which the valve element causes the degree of opening of the refrigerant passage to be maximal such that a flow rate of the refrigerant flowing through the refrigerant passage is maximal in the second flow region when it is not necessary to decompress the refrigerant flowing through the refrigerant passage. [5] Expansion valve device according to any one of claims 1 to 3, wherein the first mode is a first decompression-expansion mode in which the refrigerant is decompressed and expanded in the first flow region, the second mode is a second decompression-expansion mode in which the refrigerant is decompressed and expanded in the second flow region, and the actuator control device increases the value of the constant current when changing the mode to be greater than both a value of the constant current when the opening degree is changed to the first mode and a value of the constant current when the opening degree is changed to the second mode. [6] Expansion valve device according to claim 1, wherein The drive control unit is set up to determine whether the number of steps to be performed by the stepper motor is greater than or equal to a predetermined value (S230) when it is determined that there is no mode change in the refrigeration circuit; the drive control device is set up to adjust the constant current value (A1) in the first mode (S240) when it is determined that the number of steps is less than the predetermined value; and The drive control device is set up to adjust the value (A2) of the constant current during mode change (S270) when it is determined that the number of steps is greater than or equal to the predetermined value.

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