JP7195171B2 - refrigeration cycle equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a refrigeration cycle apparatus having a variable capacity compressor, and more particularly belongs to the technical field of control of a variable capacity compressor.

BACKGROUND ART Conventionally, a refrigeration cycle device equipped with a variable capacity compressor may be used in a vehicle air conditioner. Control of a variable capacity compressor is generally performed by feedback control such as PI control or PID control (see Patent Documents 1 and 2, for example).

In Patent Document 1, a refrigeration cycle device that cools air blown into a vehicle interior through an evaporator, and a control means that calculates a control value that determines the drive output of the compressor and controls the operation of the compressor. When starting the compressor, the control means drives the compressor according to a control value determined based on the pressure of the refrigerant in the refrigeration cycle device. This control value is the ratio of the drive output to the maximum capacity of the compressor, for example, the duty ratio as the drive signal input to the compressor by the control means. When the compressor is started, the control value of the compressor is determined based on the pressure in the refrigeration cycle and the drive output is controlled, thereby preventing excessive thermal load on the evaporator during startup. The overshoot of the air temperature downstream of the evaporator due to supercooling of the evaporator is suppressed by suppressing the operation with the control value.

In Patent Document 2, after calculating a control initial value for controlling the compressor and controlling the compressor with the control initial value, the compressor is operated with the control initial value until it is determined that the evaporator has reached a predetermined temperature state. After it is determined that the evaporator has reached a predetermined temperature state, the compressor is controlled with a capacity control value calculated from the temperature deviation between the target evaporator temperature and the actual evaporator temperature.

JP 2008-13165 A JP 2014-172478 A

By the way, in PI control and PID control, assuming that the evaporator temperature responds immediately after outputting a control signal to the compressor so as to reduce the overshoot and undershoot of the evaporator temperature, the control initial value and I am trying to adjust the control gain.

However, for example, during transitional periods, the evaporator temperature may overshoot or undershoot excessively, resulting in the problem that it takes a long time for the evaporator temperature to reach the target evaporator temperature and stabilize. there were.

That is, depending on the situation before the operation of the refrigeration cycle apparatus, even if the compressor is turned on and the control signal is output, it takes time for the evaporator temperature to decrease, and the evaporator temperature response may be delayed. And this delay time is not constant but varies. In conventional feedback control, while the response of the evaporator temperature is delayed, an excessive control signal is output so that the evaporator temperature reaches the target evaporator temperature quickly. As a result, hunting may occur.

In order to prevent the overshoot and undershoot of the evaporator temperature from increasing, it is conceivable to reduce the PID gain and limit the control signal. It takes a long time for the temperature to stabilize.

SUMMARY OF THE INVENTION The present invention has been made in view of this point, and an object of the present invention is to improve the stability and responsiveness of the evaporator temperature.

In order to achieve the above object, a first invention includes a variable capacity compressor, an evaporator that evaporates refrigerant discharged from the variable capacity compressor, and a control device that controls the variable capacity compressor. in the refrigeration cycle apparatus, a blowing amount estimating means for estimating a blowing amount blown to the evaporator; an evaporator inlet temperature detecting means for detecting an evaporator inlet temperature that is the temperature of the air flowing into the evaporator; Evaporator outlet temperature detection means for detecting an evaporator outlet temperature, which is the temperature of the air flowing out of the evaporator, and a target for calculating a target evaporator outlet temperature immediately before switching the variable capacity compressor from a stopped state to an operating state. calculated by the evaporator outlet temperature calculation means, the air flow estimated by the air flow estimation means, the evaporator inlet temperature detected by the evaporator inlet temperature detection means, and the target evaporator outlet temperature calculation means; control initial value determining means for determining a control initial value for the variable displacement compressor based on the target evaporator outlet temperature obtained and the temperature deviation of the evaporator outlet temperature detected by the evaporator outlet temperature detecting means; and holding time determining means for determining a holding time for holding the control initial value determined by the control initial value determining means, wherein the control device determines the control initial value determined by the control initial value determining means. is continuously output to the variable displacement compressor for a predetermined holding time determined by the holding time determination means, and after the holding time has elapsed, the target evaporator outlet temperature and the evaporator It is characterized in that it is configured to perform normal control according to the temperature deviation from the outlet temperature.

According to this configuration, the control initial value of the variable displacement compressor is determined based on the air flow rate to the evaporator, the evaporator inlet temperature, the target evaporator outlet temperature, and the temperature deviation of the evaporator outlet temperature. be. When this control initial value is output to the variable capacity compressor, the variable capacity compressor is switched from the stopped state to the operating state. The control initial value is set based on the amount of air blown to the evaporator, the evaporator inlet temperature, the target evaporator outlet temperature, and the temperature deviation of the evaporator outlet temperature. is reflected, and is an initial control value suitable for the situation. Since this control initial value is continuously output to the variable displacement compressor for a predetermined holding time, even if the response of the evaporator temperature is delayed, overshoot or undershoot of the evaporator temperature does not occur. The evaporator temperature quickly reaches the target evaporator temperature and stabilizes.

In a second aspect of the invention, the holding time determination means includes the air flow estimated by the air flow estimation means, the evaporator inlet temperature detected by the evaporator inlet temperature detection means, and the target evaporator outlet. The holding time is determined based on at least one of the target evaporator outlet temperature calculated by the temperature calculation means and the temperature deviation of the evaporator outlet temperature detected by the evaporator outlet temperature detection means. It is characterized by

According to this configuration, the holding time for holding the control initial value is a time suitable for the situation before the operation of the refrigeration cycle apparatus.

In a third invention, the refrigeration cycle device is used as part of a vehicle air conditioner mounted on a vehicle, and the variable capacity compressor is driven by an engine of the vehicle and detects the rotation speed of the engine. An engine rotation speed detection means is provided, and the retention time determination means is configured to determine the retention time based on the engine rotation speed detected by the engine rotation speed detection means.

That is, when the variable capacity compressor is driven by the engine of the vehicle, the amount of input to the variable capacity compressor greatly varies depending on the engine speed. By determining the holding time based on the engine speed, the holding time becomes an appropriate time according to the engine speed.

In a fourth aspect of the invention, the control device is configured to change a control gain of the variable displacement compressor during normal control according to the evaporator inlet temperature detected by the evaporator inlet temperature detection means. It is characterized by

According to this configuration, it becomes possible to apply a control gain according to the evaporator inlet temperature.

A fifth aspect of the invention is characterized in that the control device is configured to perform stepwise control for changing the control gain stepwise.

A sixth aspect of the invention is characterized in that the control device is configured to change the control gain according to the evaporator outlet temperature detected by the evaporator outlet temperature detection means.

With this configuration, it is possible to change the control gain stepwise according to the evaporator outlet temperature, so that the control reflects the degree of evaporation of the refrigerant in the evaporator.

In a seventh aspect of the invention, the control device determines the evaporator outlet temperature for changing the control gain by adjusting the air flow rate estimated by the air flow rate estimation means and the air flow rate detected by the evaporator inlet temperature detection means. The evaporator inlet temperature and the target evaporator outlet temperature calculated by the target evaporator outlet temperature calculation means are configured to be changed.

According to this configuration, when changing the control gain, by using the evaporator outlet temperature that is changed according to the air flow rate, the evaporator inlet temperature, and the target evaporator outlet temperature, the control gain varies depending on the operating conditions of the refrigeration cycle apparatus. will change accordingly.

In an eighth aspect of the invention, the control device is configured to calculate the control gain based on the evaporator inlet temperature detected by the evaporator inlet temperature detection means and an evaporator temperature change amount. It is characterized by

According to this configuration, the control gain is appropriately set based on the evaporator inlet temperature and the evaporator temperature change amount.

In a ninth aspect of the invention, the control device is configured to end the stage control and fix the control gain to a predetermined gain when the operating time of the variable capacity compressor reaches a predetermined time or longer. It is characterized by

According to this configuration, when a predetermined time or more has passed since the start of operation of the variable displacement compressor, it is estimated that the transition period has ended and the stable period has started. it gets easier.

According to the first invention, the control initial value for the variable displacement compressor is determined based on the air flow rate to the evaporator, the evaporator inlet temperature, the target evaporator outlet temperature, and the temperature deviation of the evaporator outlet temperature. This control initial value can be determined and continuously output to the variable displacement compressor for a predetermined holding time. can improve sexuality.

According to the second invention, the holding time for holding the initial control value is suitable for the situation before the operation of the refrigeration cycle apparatus, so that the stability and responsiveness of the evaporator temperature can be further improved. can.

According to the third invention, when the variable capacity compressor is driven by the vehicle engine, the control initial value can be set to an appropriate time according to the vehicle engine.

According to the fourth and fifth inventions, the control gain during normal control can be set to the control gain corresponding to the evaporator inlet temperature.

According to the sixth invention, since the control gain during normal control can be changed according to the evaporator outlet temperature, it is possible to perform control that reflects the degree of evaporation of the refrigerant in the evaporator.

According to the seventh invention, the control gain can be changed using the evaporator outlet temperature that is changed by the air flow rate, the evaporator inlet temperature, and the target evaporator outlet temperature. It is possible to set the control gain accordingly.

According to the eighth invention, the control gain can be appropriately set based on the evaporator inlet temperature and the evaporator temperature change amount.

According to the ninth invention, the control can be simplified when the transient period enters the stable period.

1 is a schematic configuration diagram of a vehicle air conditioner provided with a refrigeration cycle device according to an embodiment of the present invention; 1 is a block diagram of a vehicle air conditioner; FIG. 4 is a flow chart showing a procedure of compressor control; 4 is a flowchart showing a procedure for determining control gains; It is a graph which shows the judgment point. 4 is a graph showing changes in temperature and changes in control values of respective parts;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings. It should be noted that the following description of preferred embodiments is essentially merely illustrative, and is not intended to limit the invention, its applications, or its uses.

FIG. 1 is a schematic configuration diagram of a vehicle air conditioner 1 according to an embodiment of the present invention. This vehicle air conditioner 1 is mounted in a vehicle such as an automobile, for example, and after introducing one or both of the air inside the vehicle (inside air) and the air outside the vehicle (outside air) to adjust the temperature, It is configured to supply each part of the passenger compartment. Although not shown, the interior of the vehicle is provided with a front seat consisting of a driver's seat and a passenger's seat, and a rear seat arranged behind the front seat.

As shown in FIGS. 1 and 5 , the vehicle air conditioner 1 includes an air conditioning casing 30 , a control device 50 and a refrigeration cycle device 60 . The air-conditioning casing 30 is housed inside an instrument panel (not shown) disposed at the front end of the passenger compartment, for example. The air conditioning casing 30 includes a blower casing 20, a temperature control section 31, and a blowing direction switching section 40 in order from the upstream side to the downstream side in the air flow direction. The blower casing 20 is formed with an outside air introduction port 2a and an inside air introduction port 2b. The outside air introduction port 2a communicates with the outside of the vehicle compartment via, for example, an intake duct (not shown), and introduces air outside the vehicle compartment (outside air). The inside air introduction port 2b is open inside the instrument panel, and introduces the air (inside air) in the vehicle interior to circulate it in the vehicle interior. The amount of outside air introduced from the outside air introduction port 2a is the amount of outside air introduced. The amount of inside air introduced from the inside air introduction port 2b is the amount of inside air circulation.

Inside the blower casing 20, inside/outside air switching dampers 6 and 7 for opening and closing the outside air introduction port 2a and the inside air introduction port 2b are arranged. The inside/outside air switching dampers 6 and 7 are driven by an inside/outside air switching actuator 9 to an arbitrary rotation angle. This allows the intake mode to be switched. The inside/outside air switching actuator 9 is controlled by a control device 50 as will be described later, and is composed of a conventionally known variable torque electric actuator.

As shown in FIG. 1, the blower casing 20 is provided with a blower 5 as an air conditioning device. When the blower 5 operates, the air flows inside the blower casing 20 , and air for air conditioning is blown to the temperature control section 31 provided on the downstream side of the blower casing 20 .

The temperature adjustment part 31 is a part for regulating the temperature of the air for air conditioning introduced from the blower casing 20, through which air flows. A cooling heat exchanger 32 , a heating heat exchanger 33 , and an air mix damper 34 are provided inside the temperature control unit 31 . The cooling heat exchanger 32 and the heating heat exchanger 33 are air conditioning equipment.

That is, inside the temperature control unit 31, a cold air passage R1 is formed on the upstream side in the air flow direction, and the cooling heat exchanger 32 is accommodated in the cold air passage R1. Further, the downstream side of the cold air passage R1 branches into a hot air passage R2 and a bypass passage R3, and a heating heat exchanger 33 is accommodated in the hot air passage R2.

The cooling heat exchanger 32 is composed of a refrigerant evaporator of the refrigeration cycle device 60 and the like. In the description of this embodiment, the cooling heat exchanger 32 may also be referred to as a refrigerant evaporator (evaporator) or an evaporator. Also, the heating heat exchanger 33 can be composed of a heater core or the like supplied with cooling water for an engine (not shown) mounted in the engine room of the vehicle, for example, but is not limited to this. Any device capable of heating air, such as an electric heater, may be used. Also, an electric heater can be added as an auxiliary heat source.

The air mix damper 34 is arranged between the cooling heat exchanger 32 and the heating heat exchanger 33, and opens and closes the upstream end of the hot air passage R2 and the upstream end of the bypass passage R3. The air mix damper 34 can be made of, for example, a plate-like member, and has a rotation shaft (not shown) that is rotatably supported on the side wall of the temperature control section 31 . The air mix damper 34 is driven by an air mix actuator 35 to an arbitrary rotation angle. The air mix actuator 35 is controlled by the control device 50, and is composed of a variable torque electric actuator. A link member (not shown) that transmits the force output from the air mix actuator 35 to the rotation shaft of the air mix damper 34 is arranged between the rotation shaft of the air mix damper 34 and the air mix actuator 35 . is set.

When the air mix damper 34 fully opens the upstream end of the hot air passage R2 and fully closes the upstream end of the bypass passage R3, the entire amount of cold air generated in the cold air passage R1 flows into the hot air passage R2 and is heated. Therefore, warm air flows into the blowing direction switching unit 40 . On the other hand, when the air mix damper 34 fully closes the upstream end of the hot air passage R2 and fully opens the upstream end of the bypass passage R3, all the cold air generated in the cold air passage R1 flows into the bypass passage R3. , the cold air flows into the blowing direction switching unit 40 . When the air mix damper 34 is in the rotational position to open the upstream end of the hot air passage R2 and the upstream end of the bypass passage R3, cold air and warm air flow into the blowout direction switching portion 40 in a mixed state. The rotation position of the air mix damper 34 changes the amount of cool air and the amount of warm air flowing into the blowout direction switching unit 40 to generate conditioned air at a desired temperature. The air mix damper 34 is not limited to the plate-like damper described above, and may have any structure as long as it is capable of changing the amount of cold air and the amount of warm air. For example, it may be a rotary damper, a film damper, a louver damper, or the like. Further, the configuration for temperature control does not have to be the configuration described above, as long as it can change the amount of cool air and the amount of warm air.

The blow-off direction switching unit 40 is a portion for circulating the conditioned air temperature-controlled by the temperature control unit 31 and for supplying the temperature-controlled conditioned air to each part of the passenger compartment. A defroster outlet 42 , a vent outlet 43 , and a heat outlet 45 are formed in the outlet direction switching section 40 . The defroster outlet 42 is connected to a defroster nozzle 41 formed in the instrument panel. The defroster outlet 42 is for supplying conditioned air to the interior surface of the front windshield (window glass) G. As shown in FIG. A defroster damper 42 a for opening and closing the defroster outlet 42 is provided inside the defroster outlet 42 .

The vent outlet 43 is connected to a vent nozzle 44 formed in the instrument panel. The vent nozzles 44 are for supplying conditioned air to the upper bodies of the front seat occupants, and are provided at the center of the instrument panel in the vehicle width direction and on both left and right sides. A vent damper 43 a for opening and closing the vent outlet 43 is provided inside the vent outlet 43 .

The heat outlet 45 is connected to a heat duct 46 extending to the vicinity of the passenger's feet. The heat duct 46 is for supplying conditioned air to the feet of the passenger. A heat damper 45 a for opening and closing the heat outlet 45 is provided inside the heat outlet 45 .

The defroster damper 42a, the vent damper 43a, and the heat damper 45a have a rotation shaft (not shown) that is rotatably supported on the side wall of the blowout direction switching section 40. As shown in FIG. The defroster damper 42a, the vent damper 43a, and the heat damper 45a are driven by a blowout direction switching actuator 47 to open and close. The blowing direction switching actuator 47 is composed of a torque variable electric actuator. Between the rotation shafts of the defroster damper 42a, the vent damper 43a and the heat damper 45a and the blowout direction switching actuator 47, the force output from the blowout direction switching actuator 47 is applied to the rotation shafts of the defroster damper 42a, the vent damper 43a and the heat damper 45a. A link member (not shown) is provided for transmitting to.

The blowing direction switching actuator 47 is controlled by the control device 50 . The defroster damper 42a, the vent damper 43a, and the heat damper 45a are interlocked via a link (not shown). The vent mode in which the damper 42a and the heat damper 45a are closed and the vent damper 43a is open, the heat mode in which the defroster damper 42a and the vent damper 43a are closed and the heat damper 45a is open, and the defroster damper 42a and the vent damper 43a are open. , the blowout mode can be switched to an arbitrary blowout mode among a plurality of blowout modes such as a differential vent mode in which the heat damper 45a is in a closed state and a bi-level mode in which the defroster damper 42a and the heat damper 45a are in an open state and the vent damper 43a is in a closed state. .

(Configuration of blower unit)
In this embodiment, the blower unit operates in an inside air circulation mode in which only the inside air introduction port 2b is opened by the first and second inside/outside air switching dampers 6 and 7, an outside air introduction mode in which only the outside air introduction port 2a is opened, the inside air introduction port 2b and the outside air. Although it is possible to switch between the inside and outside air two-layer flow mode by opening the inlet 2a, the present invention does not have the inside and outside air two-layer flow mode, and the blower unit can be switched between the inside air circulation mode and the outside air introduction mode. can also be applied to

The first inside/outside air switching damper 6 and the second inside/outside air switching damper 7 are driven by the inside/outside air switching actuator 9 shown in FIG. In this embodiment, the first inside/outside air switching damper 6 and the second inside/outside air switching damper 7 are driven as follows. That is, in the outside air introduction mode, only the outside air is introduced into the blower casing 20 by the first inside/outside air switching damper 6 and the second inside/outside air switching damper 7, and in the inside air circulation mode, the first inside/outside air switching damper 6 and the second Only the inside air is introduced into the blower casing 20 by the inside/outside air switching damper 7 . In the inside/outside air two-layer flow mode, outside air and inside air are introduced into the blower casing 20 by the first inside/outside air switching damper 6 and the second inside/outside air switching damper 7 . The inside/outside air two-layer flow mode is a mode used during heating.

Switching among the internal air circulation mode, the external air introduction mode, and the internal/external air two-layer flow mode is performed by a conventionally well-known automatic air conditioner control. By setting the inside/outside air two-layer flow mode, in winter, relatively dry outside air is supplied to the defrost outlet to clear the fog on the windshield, while relatively warm inside air is supplied to the heat outlet. Heating efficiency can be improved.

A fan 5a and a blower motor 5b for rotating the fan 5a are provided on the lower side of the blower casing 20. As shown in FIG. When voltage is applied to the blower motor 5b, the rotational force of the blower motor 5b is transmitted to the fan 5a to rotate the fan 5a. A control device 50 is connected to the blower motor 5b, and a voltage is applied to the blower motor 5b by the control device 50 so as to achieve a desired rotational speed.

(Configuration of refrigeration cycle device 60)
As shown in FIG. 1, the refrigeration cycle device 60 includes a variable capacity compressor 61, the cooling heat exchanger 32 that evaporates the refrigerant discharged from the variable capacity compressor 61, the variable capacity compressor 61 and the cooling It has an expansion valve 62 arranged between the heat exchangers 32 and a condenser 63 arranged outside the passenger compartment. The variable capacity compressor 61 , the cooling heat exchanger 32 , the expansion valve 62 and the condenser 63 are connected by a refrigerant pipe 64 so that the refrigerant circulates inside the refrigeration cycle device 60 . Further, the control device 50 can be a member that constitutes the refrigeration cycle device 60 . In this embodiment, the refrigeration cycle device 60 is used as part of the vehicle air conditioner 1 mounted on a vehicle, but the refrigeration cycle device 60 is used for other purposes. good too.

The variable capacity compressor 61 has a variable capacity mechanism configured to change the refrigerant discharge amount per unit time, and the capacity can be changed by a control signal output from the control device 50. there is This variable capacity mechanism is a conventionally well-known mechanism. If the variable displacement mechanism is configured by a mechanism including, for example, an electromagnetic valve, etc., the amount of refrigerant discharged from the variable displacement compressor 61 per unit time can be changed by a control signal output from the control device 50. can. The amount of refrigerant discharged per unit time can be changed to an arbitrary amount by a control signal output to the variable capacity mechanism. is configured to Also, the control value of the variable capacity compressor 61 can be the ratio of the output to the maximum capacity of the variable capacity compressor 61, for example, the duty ratio.

Refrigerant circulating inside the refrigeration cycle device 60 is compressed by the variable capacity compressor 61, flows into the expansion valve 62, and is decompressed into a gas-liquid two-phase state. The refrigerant decompressed by the expansion valve 62 flows into the cooling heat exchanger 32 and exchanges heat with the air-conditioning air passing outside to evaporate, and then flows into the condenser 63 . After passing through the condenser 63 and exchanging heat with the outside air, the refrigerant flows into the variable displacement compressor 61 and is compressed.

Also, the variable capacity compressor 61 is driven by the engine E of the vehicle. That is, a pulley E1 is provided on the output shaft of the engine E, and a transmission belt E2 is wound around the pulley E1 and a pulley 61a provided on the input shaft of the variable capacity compressor 61. As shown in FIG. When the engine E is in operation, rotational force is input to the input shaft of the variable capacity compressor 61 via the pulley E1, the transmission belt E2 and the pulley 61a.

An intermittent mechanism such as an electromagnetic clutch 61b (shown in FIG. 2) can be provided between the compression mechanism of the variable capacity compressor 61 and the pulley 61a. The electromagnetic clutch 61b is controlled by the control device 50 and is connected only when the variable capacity compressor 61 needs to be operated, and is disconnected otherwise. This electromagnetic clutch 61b may be omitted.

(Various sensors)
As shown in FIG. 2, the vehicle air conditioner 1 includes, for example, an outside air temperature sensor (outside air temperature detection means) 51, an inside air temperature sensor (inside air temperature detection means) 52, a solar radiation sensor (solar radiation amount detection means) 53, an evaporator A rear temperature sensor 54, an air conditioning operation switch 55, an evaporator inlet temperature detection sensor 56, an engine speed sensor 57, and the like are provided. An outside air temperature sensor 51, an inside air temperature sensor 52, a solar radiation sensor 53, a post-evaporator temperature sensor 54, an evaporator inlet temperature sensor 56, and an engine speed sensor 57 are connected to the control device 50 and output signals to the control device 50. doing. The air conditioning operation switch 55 is connected to the control device 50 so that the control device 50 can detect the operating state of the passenger.

The outside air temperature sensor 51 is arranged, for example, in the front part or the side part of the vehicle outside the vehicle, and detects the air temperature around the vehicle (outside air temperature). The inside air temperature sensor 52 is arranged, for example, in the vicinity of the instrument panel in the vehicle compartment, and detects the air temperature (inside air temperature) in the vehicle compartment. The solar radiation sensor 53 is arranged, for example, in the vicinity of the instrument panel in the vehicle compartment, and detects the amount of solar radiation irradiated to the vehicle compartment.

The inside air temperature sensor 52, the outside air temperature sensor 51, and the solar radiation sensor 53 are capable of detecting information related to cold or heat felt by the occupants. That is, the inside air temperature output from the inside air temperature sensor 52 is substantially equal to the ambient temperature of the occupant, and the occupant feels warm when the inside air temperature is high, and feels cold when the inside air temperature is low. . Further, when the outside air temperature output from the outside air temperature sensor 51 is high, the occupant feels warm, and when the outside air temperature is low, the occupant feels cold. Furthermore, when the amount of solar radiation output from the solar radiation amount sensor 53 is large, the occupant feels warm, and when the amount of solar radiation output is small, the occupant feels cold.

The post-evaporator temperature sensor 54 is disposed on the downstream side of the cooling heat exchanger 32 in the air flow direction, and detects the surface temperature of the cooling heat exchanger 32 . The post-evaporator temperature sensor 54 also functions as evaporator outlet temperature detection means for detecting the evaporator outlet temperature, which is the temperature of the air flowing out of the cooling heat exchanger 32 . Since the post-evaporator temperature sensor 54 and the downstream surface of the cooling heat exchanger 32 in the air flow direction are in contact or close to each other, the post-evaporator temperature sensor 54 detects the downstream surface of the cooling heat exchanger 32 in the air flow direction. , that is, the temperature of the air flowing out of the cooling heat exchanger 32 can be detected.

The air-conditioning operation switch 55 is arranged, for example, on an instrument panel or the like. , an inside/outside air selector switch for switching between inside air circulation, outside air introduction, and inside/outside air mixing modes, an auto switch for selecting whether or not to use automatic air conditioner control, a blowout mode selector switch for switching the blowout direction, a defroster switch, and the like.

The evaporator inlet temperature detection sensor 56 is evaporator inlet temperature detection means for detecting the evaporator inlet temperature, which is the temperature of the air flowing into the cooling heat exchanger 32 . The evaporator inlet temperature detection sensor 56 can be arranged on the upstream side of the cooling heat exchanger 32 in the air flow direction, for example, inside the air conditioning casing 30 or inside the blower casing 20 . It is also possible to estimate the temperature of the air flowing into the cooling heat exchanger 32 based on the value detected by the outside air temperature sensor 51 without providing the evaporator inlet temperature detection sensor 56 . A conventionally well-known method can be used as an estimation method. For example, there is a method of using the outside air temperature sensor 51 and the inside air temperature sensor 52 and further acquiring the inside air circulation rate in the vehicle interior. The inside air circulation rate can be obtained based on the outside air introduction amount and the inside air circulation amount adjusted by the inside/outside air switching dampers 6 and 7. When the outside air introduction amount is 0, the inside air circulation rate is set to 100%, and the inside air circulation rate is When the amount is 0, the internal air circulation rate can be 0%. Then, the following equation makes it possible to estimate the evaporator inlet temperature.

Evaporator inlet temperature (estimated value) = inside air temperature sensor detected temperature (°C) × inside air circulation rate (%) + outside air temperature sensor detected temperature (°C) × (100% - inside air circulation rate)

The engine rotation speed sensor (engine rotation speed detection means) 57 is a sensor for detecting the rotation speed (rpm) of the crankshaft of the engine E, and is a conventionally well-known sensor.

(Configuration of control device 50)
The control device 50 operates the inside/outside air switching actuator 9 and the air mix actuator based on the signals (output values) output from the sensors 51 to 54, 56, 57 and other sensors and the operation state of the air conditioning operation switch 55. 35, blowing direction switching actuator 47, blower motor 5b and refrigerating cycle device 60 are controlled.

That is, when automatic air conditioning control is selected by the auto switch of the air conditioning operation switch 55, the temperature outside the vehicle, the temperature inside the vehicle, the amount of solar radiation, the engine cooling water temperature, the surface temperature of the cooling heat exchanger 32, the setting Based on the temperature and the like, the target blowout temperature of the conditioned air to be supplied into the passenger compartment is determined, and the opening degree of the air mix damper 34 is calculated so as to achieve this target blowout temperature. By controlling the air mix actuator 35, the air mix damper 34 is rotated. As a result, the temperature of the conditioned air becomes the target blowout temperature.

Further, the control device 50 controls the blowout direction switching actuator 47 so that the blowing mode is mainly the vent mode during cooling, and the blowing direction switching actuator 47 is controlled so that the blowing mode is mainly the heat mode during heating. . Also, if the airflow is rather weak even during cooling or heating, the blowout direction switching actuator 47 is controlled so as to switch to the bi-level mode or the differential vent mode. Furthermore, when the defroster switch of the air conditioning operation switch 55 is turned on, the blowout direction switching actuator 47 is controlled so that the blowout mode becomes the defroster mode.

For example, when heating a vehicle that has been left for a long time in winter or cooling a vehicle that has been left for a long time in summer, the difference between the target blowout temperature and the inside air temperature increases. In such a case, the control device 50 controls the blower motor 5b so as to increase the air volume, but the passenger can operate the air volume changeover switch to set the desired air volume. Further, in automatic air conditioner control, the blower motor 5b is controlled so that the air volume decreases as the difference between the target air temperature and the inside air temperature decreases. Although the control of the blower motor 5b is performed by changing the applied voltage, it is not limited to this, and the number of revolutions of the blower motor 5b may be changed.

In addition, the control device 50 includes a blowing amount estimating means 50a. The blowing amount estimating means 50a is a part for estimating the blowing amount of air blown to the cooling heat exchanger 32. Specifically, the voltage applied to the blower motor 5b is detected, and cooling is performed based on this voltage. The amount of air blown to the heat exchanger 32 is estimated. It is estimated that the higher the voltage applied to the blower motor 5b, the greater the amount of air blown to the cooling heat exchanger 32, and the lower the voltage applied to the blower motor 5b, the more air is blown to the cooling heat exchanger 32. It is estimated that the amount of air blown is small. Further, the blowing amount estimating means 50a may be configured to estimate the blowing amount of air blown to the cooling heat exchanger 32 by detecting the rotation speed of the blower motor 5b.

The control device 50 also includes target evaporator outlet temperature computing means 50b. The target evaporator outlet temperature calculation means 50b is a part for calculating the target evaporator outlet temperature immediately before switching the variable capacity compressor 61 from the stopped state to the operating state. The target evaporator outlet temperature can be calculated, for example, based on the outside air temperature, the inside air temperature, the temperature set by the crew, etc. Strong cooling is required when the outside air temperature or inside air temperature is high and the temperature set by the crew is low. In this case, the target evaporator outlet temperature is calculated to be high, and conversely, if weak cooling is sufficient, the target evaporator outlet temperature is calculated to be low.

The control device 50 also includes control initial value determination means 50c. The control initial value determination means 50c determines the air flow estimated by the air flow estimation means 50a, the evaporator inlet temperature detected by the evaporator inlet temperature detection sensor 56, and the target evaporator outlet temperature calculated by the target evaporator outlet temperature calculation means 50b. The control initial value of the variable capacity compressor 61 is determined based on the target evaporator outlet temperature and the temperature deviation of the evaporator outlet temperature detected by the post-evaporator temperature sensor 54 . The control initial value is changed in the direction of increasing the discharge capacity of the variable displacement compressor 61 as the air flow rate estimated by the air flow rate estimation means 50a increases. The displacement of the variable displacement compressor 61 is changed to decrease as the displacement decreases. The control initial value is changed so that the higher the evaporator inlet temperature detected by the evaporator inlet temperature detection sensor 56 is, the more the discharge capacity of the variable displacement compressor 61 is increased. The lower the detected evaporator inlet temperature, the more the displacement of the variable displacement compressor 61 is reduced.

Further, the larger the temperature deviation between the target evaporator outlet temperature calculated by the target evaporator outlet temperature calculation means 50b and the evaporator outlet temperature detected by the post-evaporator temperature sensor 54, the more the discharge capacity of the variable capacity compressor 61 increases. is changed to increase the control initial value. Also, the smaller the temperature deviation between the target evaporator outlet temperature calculated by the target evaporator outlet temperature calculation means 50b and the evaporator outlet temperature detected by the post-evaporator temperature sensor 54, the more the displacement of the variable capacity compressor 61 increases. is changed to decrease the control initial value.

The control device 50 also includes a holding time determining means 50d. The holding time determination means 50d is a part that determines a holding time for holding the control initial value determined by the control initial value determination means 50c. At least one of the evaporator inlet temperature detected by the sensor 56 and the temperature deviation between the target evaporator outlet temperature calculated by the target evaporator outlet temperature calculator 50b and the evaporator outlet temperature detected by the post-evaporator temperature sensor 54 determine the retention time based on

The retention time is determined so as to be longer as the air flow rate estimated by the air flow rate estimation means 50a increases, and is changed so as to be shorter as the air flow rate estimated by the air flow rate estimation section 50a decreases. . The holding time is determined so that the higher the evaporator inlet temperature detected by the evaporator inlet temperature detection sensor 56 is, the longer the holding time is. It is determined so that the lower the value, the shorter the value.

Further, the retention time is determined to be longer as the temperature deviation between the target evaporator outlet temperature calculated by the target evaporator outlet temperature calculating means 50b and the evaporator outlet temperature detected by the post-evaporator temperature sensor 54 increases. be done. Further, the retention time is determined so that the smaller the temperature deviation between the target evaporator outlet temperature calculated by the target evaporator outlet temperature calculating means 50b and the evaporator outlet temperature detected by the post-evaporator temperature sensor 54, the shorter the holding time. be.

Further, the retention time determining means 50d may be configured to determine the retention time based on the engine speed detected by the engine speed sensor 57. FIG. The holding time is determined so that the higher the engine speed detected by the engine speed sensor 57, the shorter the holding time, and the lower the engine speed detected by the engine speed sensor 57, the longer the holding time. A retention time is determined.

The control device 50 performs initial value holding control to continuously output the control initial value determined by the control initial value determining means 50c to the variable capacity compressor 61 for a predetermined holding time determined by the holding time determining means 50d. , after the predetermined holding time determined by the holding time determining means 50d has elapsed, normal control is performed according to the target evaporator outlet temperature and the temperature deviation from the evaporator outlet temperature (see FIG. 6). . The initial value holding control is performed immediately after switching the variable capacity compressor 61 from the stopped state to the operating state. , and at the same time, the control initial value is output to the variable displacement compressor 61 . Measurement of the retention time is started immediately after switching the variable capacity compressor 61 from the stopped state to the operating state.

As shown in FIG. 6, the control device 50 outputs a control initial value when switching the variable capacity compressor 61 from a stopped state to an operating state. Then, the variable capacity compressor 61 starts operating with a capacity corresponding to the control initial value, and thereafter the evaporator outlet temperature decreases with a response delay. The response delay differs depending on the situation. For example, the higher the ambient temperature, the longer the delay time tends to be. Further, for example, the delay time tends to be longer if the rotation speed of the engine E is low.

Although the controller 50 detects a drop in the evaporator outlet temperature, it continues the initial value holding control for the holding time. continues to operate. The control device 50 performs normal control after the retention time has elapsed. In normal control, the target evaporator outlet temperature is calculated, and a control signal is output to the variable capacity compressor 61 so that the evaporator outlet temperature becomes the target evaporator outlet temperature, and the capacity of the variable capacity compressor 61 is increased or decreased. Let

The control device 50 is configured to change the control gain of the variable displacement compressor 61 during normal control according to the evaporator inlet temperature detected by the evaporator inlet temperature detection sensor 56, and the control gain is changed in stages. Step-by-step control is performed to change the The control device 50 may be configured to change the control gain according to the evaporator outlet temperature detected by the post-evaporator temperature sensor 54 .

The controller 50 determines the evaporator outlet temperature for changing the control gain based on the air flow rate estimated by the air flow rate estimation means 50a, the evaporator inlet temperature detected by the evaporator inlet temperature detection sensor 56, and the target evaporator outlet temperature. It can be configured to change according to the target evaporator outlet temperature calculated by the temperature calculating means 50b. Furthermore, the control device 50 can be configured to calculate the control gain based on the evaporator outlet temperature and the amount of change in the evaporator temperature. Further, the control device 50 can be configured to end the stage control and fix the control gain to a predetermined gain when the operation time of the variable displacement compressor 16 reaches a predetermined time or longer. This predetermined time can be defined as the time required for the room temperature in the passenger compartment to pass through the transitional period and enter the stable period. When the degree of change in is small or when there is almost no change, it is determined that the time is longer than the predetermined time. If the difference between the set temperature and the vehicle interior temperature is large, it is assumed that the time is less than the predetermined time. .

Specific control contents of the control device 50 will be described below with reference to FIGS. 3 to 5. FIG. FIG. 3 shows the control performed after the air conditioning temperature control is started. Air-conditioning temperature control is started by an air-conditioning ON operation or the like by a passenger. At step SA1, an air conditioning temperature control signal is input. At step SA2, the target post-evaporator temperature, that is, the evaporator outlet temperature, which is the temperature of the air flowing out from the cooling heat exchanger 32, is acquired. At step SA3, the control input signal at the start of control is calculated by the control initial value determining means 50c. At step SA4, the evaporator inlet temperature is predicted based on the temperature detected by the evaporator inlet temperature detection sensor 56. FIG. At step SA5, the initial control signal StartDuty (control initial value) for the variable capacity compressor 61 is determined by the control initial value determining means 50c. Further, the holding time determining means 50d calculates the holding time.

Thereafter, at step SA6, the controller 50 outputs the initial control signal StartDuty as a control value. In step SA7, it is determined whether or not the time (compressor operating time) that has elapsed immediately after switching the variable displacement compressor 61 from the stopped state to the operating state is equal to or less than the retention time (initial value MIN retention time). If the determination in step SA7 is YES, it means that the compressor operating time has not passed the initial value MIN holding time, and the process returns to step SA7. If the determination in step SA7 is NO, it means that the compressor operation time has passed the initial value MIN holding time, and the process proceeds to step SB1 of the flowchart shown in FIG. At step SB1, the post-evaporator temperature Tevap, that is, the evaporator outlet temperature, which is the temperature of the air flowing out from the cooling heat exchanger 32, is read.

After that, the process proceeds to step SB2, and it is determined whether or not the time (compressor operating time) that has elapsed immediately after switching the variable capacity compressor 61 from the stopped state to the operating state is equal to or shorter than a predetermined time. If the determination in step SB2 is YES, it means that the compressor operating time has not passed the predetermined time, and the process returns to step SA7 of the flow chart shown in FIG. If the determination in step SB2 is NO, it means that the compressor operating time has passed the predetermined time, and the process proceeds to step SB3.

At step SB3, the post-evaporator temperature change rate (evaporator temperature change amount) is determined. The post-evaporator temperature change rate is ΔTevap and is calculated by Tevap(n)−Tevap(n−1). The post-evaporator temperature change rate is determined based on the graph shown in FIG. The vertical axis indicates two types of determination, "valid" and "invalid". The horizontal axis is the value (° C.) obtained by subtracting the post-evaporator temperature Tevap(n−1) from the post-evaporator temperature Tevap(n). When this value reaches 0.1°C from the side lower than 0.1°C on the boundary between -0.1°C and 0.1°C, it becomes invalid from the effective side and the side higher than -0.1°C. from disabled to enabled when -0.1°C is reached. These judgment criteria and judging method are examples, and are not limited to these.

At step SB4, it is determined that post-evaporator temperature Tevap≧post-evaporator temperature Tevap1. In chronological order, the post-evaporator temperature Tevap1 is followed by the post-evaporator temperature Tevap. If determined as YES at step SB4, the process proceeds to step SA7 of the flowchart shown in FIG. 3, and if determined as NO at step SB4, the process proceeds to step SB5. At Step SB5, it is determined whether post-evaporator temperature Tevap1≧post-evaporator temperature Tevap>post-evaporator temperature Tevap2 and the above determination is valid. In chronological order, the temperature after the evaporator Tevap1, the temperature after the evaporator Tevap2, and the temperature after the evaporator Tevap are in order.

If YES is determined in step SB5, the process proceeds to step SB6 to determine control gain 1 (first control gain) as the control gain for normal control. At step SB7, the control value calculated based on the control gain 1 determined at step SB6 is output to the variable displacement compressor 61. FIG.

If the determination in step SB5 is NO, the process proceeds to step SB8. At Step SB8, it is determined whether post-evaporator temperature Tevap2≧post-evaporator temperature Tevap>post-evaporator temperature Tevap3 and the above determination is valid. In time series, the order is post-evaporator temperature Tevap2, post-evaporator temperature Tevap3, and post-evaporator temperature Tevap. If YES is determined in step SB8, the process proceeds to step SB9 to determine control gain 2 (second control gain) as the control gain during normal control. At step SB7, the control value calculated based on the control gain 2 determined at step SB9 is output to the variable displacement compressor 61. FIG.

If the determination in step SB8 is NO, the process proceeds to step SB10. In step SB10, it is determined whether post-evaporator temperature Tevap≦post-evaporator temperature Tevap3. In time series, the order is post-evaporator temperature Tevap and post-evaporator temperature Tevap3. If NO is determined in step SB10, the process proceeds to step SB11 to determine control gain 3 (third control gain) as the control gain during normal control. At step SB7, the control value calculated based on the control gain 3 determined at step SB11 is output to the variable displacement compressor 61. FIG.

If the determination in step SB10 is NO, the process proceeds to step SB12 to determine control gain 3 (third control gain) as the control gain during normal control. At step SB13, the control value calculated based on the control gain 3 determined at step SB12 is output to the variable capacity compressor 61. FIG. Then, in step SB14, the post-evaporator temperature is read. After reading the post-evaporator temperature in step SB14, the process proceeds to step SB12. Therefore, once the determination in step SB10 is NO, the control gain is set to 3, and the control gain of 3 is maintained until the compressor 61 is turned off without proceeding to steps SB4, SB5 and SB8 from the next control cycle.

Therefore, as shown in FIG. 6, control gain 1 is a control gain that is applied earlier than control gains 2 and 3, and control gain 2 is applied earlier than control gain 3. control gain. Control gain 1 is higher than control gains 2 and 3, and control gain 2 is higher than control gain 3.

(Action and effect of the embodiment)
As described above, according to this embodiment, based on the amount of air blown to the cooling heat exchanger 32, the evaporator inlet temperature, the target evaporator outlet temperature, and the temperature deviation of the evaporator outlet temperature, A control initial value for the variable capacity compressor 61 can be determined. When this control initial value is output to the variable capacity compressor 61, the variable capacity compressor 61 is switched from the stopped state to the operating state. Since the control initial value is set based on the amount of air blown to the cooling heat exchanger 32, the evaporator inlet temperature, the target evaporator outlet temperature, and the temperature deviation of the evaporator outlet temperature, the refrigeration cycle device 60 This is a value that reflects the situation before operation, and is an initial control value suitable for that situation. Since this control initial value is continuously output to the variable displacement compressor 61 for a predetermined holding time, even if the response of the evaporator temperature is delayed, the evaporator temperature does not overshoot or undershoot. , the cooling heat exchanger 32 quickly reaches the target evaporator temperature and stabilizes. Therefore, the temperature stability and responsiveness of the cooling heat exchanger 32 can be improved.

Further, when the variable capacity compressor 61 is driven by the engine E of the vehicle, the amount of input to the variable capacity compressor 61 greatly varies depending on the engine E rotation speed. By determining the holding time based on the number of revolutions of the engine E, the holding time becomes an appropriate time corresponding to the number of revolutions of the engine E.

In addition, when changing the control gain, by using the evaporator outlet temperature that is changed according to the air flow rate, the evaporator inlet temperature, and the target evaporator outlet temperature, the control gain changes according to the operating conditions of the refrigeration cycle device 60. will come to

The above-described embodiments are merely examples in all respects and should not be construed in a restrictive manner. Furthermore, all modifications and changes within the equivalent range of claims are within the scope of the present invention.

INDUSTRIAL APPLICABILITY As described above, the refrigeration cycle apparatus according to the present invention can be used, for example, as part of a vehicle air conditioner.

1 vehicle air conditioner 32 cooling heat exchanger (evaporator)
50 Control device 50a Air flow estimation means 50b Target evaporator outlet temperature calculation means 50c Control initial value determination means 50d Holding time determination means 54 Post-evaporator temperature sensor (evaporator outlet temperature detection means)
56 evaporator inlet temperature detection sensor (evaporator inlet temperature detection means)
57 engine speed sensor (engine speed detection means)
60 refrigeration cycle device E engine

Claims (9)

a variable capacity compressor;
an evaporator that evaporates the refrigerant discharged from the variable capacity compressor;
A refrigeration cycle apparatus comprising a control device that controls the variable capacity compressor,
a blowing amount estimating means for estimating the blowing amount blown to the evaporator;
evaporator inlet temperature detection means for detecting an evaporator inlet temperature, which is the temperature of the air flowing into the evaporator;
evaporator outlet temperature detection means for detecting an evaporator outlet temperature, which is the temperature of the air flowing out of the evaporator;
target evaporator outlet temperature calculation means for calculating a target evaporator outlet temperature immediately before switching the variable displacement compressor from a stopped state to an operating state;
The air flow rate estimated by the air flow rate estimation means, the evaporator inlet temperature detected by the evaporator inlet temperature detection means, and the target evaporator outlet temperature calculated by the target evaporator outlet temperature calculation means. and control initial value determination means for determining a control initial value for the variable displacement compressor based on the temperature deviation of the evaporator outlet temperature detected by the evaporator outlet temperature detection means;
holding time determining means for determining a holding time for holding the control initial value determined by the control initial value determining means;
The control device performs initial value holding control in which the control initial value determined by the control initial value determining means is continuously output to the variable displacement compressor for a predetermined holding time determined by the holding time determining means. and after the holding time has elapsed, normal control is performed in accordance with the temperature deviation between the target evaporator outlet temperature and the evaporator outlet temperature. In the refrigeration cycle apparatus according to claim 1,
The holding time determining means calculates the air flow rate estimated by the air flow rate estimating means, the evaporator inlet temperature detected by the evaporator inlet temperature detecting means, and the target evaporator outlet temperature calculating means. the retention time is determined based on at least one of the target evaporator outlet temperature and the temperature deviation of the evaporator outlet temperature detected by the evaporator outlet temperature detection means. refrigeration cycle equipment. In the refrigeration cycle device according to claim 1 or 2,
The refrigeration cycle device is used as part of a vehicle air conditioner mounted on a vehicle,
The variable capacity compressor is driven by the engine of the vehicle,
An engine speed detection means for detecting the speed of the engine,
The refrigeration cycle apparatus, wherein the retention time determination means is configured to determine the retention time based on the engine speed detected by the engine speed detection means. In the refrigeration cycle apparatus according to any one of claims 1 to 3,
The control device is configured to change a control gain of the variable displacement compressor during the normal control according to the evaporator inlet temperature detected by the evaporator inlet temperature detection means. refrigeration cycle equipment. In the refrigeration cycle apparatus according to claim 4,
The refrigeration cycle apparatus, wherein the control device is configured to perform stepwise control for changing the control gain stepwise. In the refrigeration cycle apparatus according to claim 5,
The refrigeration cycle apparatus, wherein the control device is configured to change the control gain according to the evaporator outlet temperature detected by the evaporator outlet temperature detection means. In the refrigeration cycle device according to claim 6,
The control device determines the evaporator outlet temperature for changing the control gain based on the air flow rate estimated by the air flow rate estimation means, the evaporator inlet temperature detected by the evaporator inlet temperature detection means, A refrigeration cycle apparatus, wherein the target evaporator outlet temperature calculated by the target evaporator outlet temperature calculation means is changed. In the refrigeration cycle apparatus according to any one of claims 5 to 7,
The control device is configured to calculate the control gain based on the evaporator inlet temperature detected by the evaporator inlet temperature detection means and an evaporator temperature change amount. cycle equipment. In the refrigeration cycle apparatus according to claim 8,
The control device is configured to end the stage control and fix the control gain to a predetermined gain when the operating time of the variable capacity compressor reaches a predetermined time or longer. cycle equipment.

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