Air conditioner

Abstract

To provide a relatively small air conditioner in which a condenser is arranged below an evaporator capable of controlling used power within a power limit of a power source and effectively utilizing air conditioning (cooling) capacity.SOLUTION: An air conditioner 100 includes a housing 60 for storing a refrigerant circuit R having a compressor 10, a condenser 20, an evaporator 30, and an expansion device 40, and a control device 50. The control device 50 includes an operation upper limit value determination part 502, a rotation speed command value determination part 503, and a compressor rotation control part 506. The operation upper limit value determination part 502 executes control to determine an operation upper limit value Rrmax of the compressor 10 according to a load for the compressor 10. The rotation speed command value determination part 503 executes control to determine a rotation speed command value Rc according to a target blowout temperature Ttgt and a present rotation speed Rnow of the compressor 10 when the load is relatively low, and determine the current rotation speed Rnow or the operation upper limit value Rrmax for the rotation speed command value Rc when the load is relatively high. The compressor rotation control part 506 drives and controls the compressor 10 on the basis of the rotation speed command value Rc.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an air conditioner. [Background technology]

[0002] Conventionally, a relatively small air conditioner (so-called spot cooler, portable cooler) is known in which a refrigerant circuit including a compressor, a condenser, an expansion device, and an evaporator, and a blower are housed in a single case, and the condenser is disposed below the evaporator. In such an air conditioner, a configuration is also known in which condensed water (drain water) generated by the evaporator is caused to flow into the condenser to cool the condenser, thereby improving the energy consumption efficiency (COP: Coefficient of Performance) (see, for example, Patent Document 1). In addition, the power sources for these air conditioners (spot coolers, portable coolers) include AC power sources, rechargeable batteries, and vehicle cigarette lighter power supplies. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-148686 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of an air conditioner that uses a cigarette lighter power supply as its power source, it has been difficult to effectively utilize the air conditioning (cooling) capacity.

[0005] Specifically, for example, the power required by an air conditioner varies greatly depending on the outdoor air environment, with high power required when operating in a high temperature / high humidity environment, i.e., when the load on the air conditioner's capacity is high, and low power required when operating in a low temperature / low humidity environment (when the load on the air conditioner's capacity is low). In the case of a cigarette lighter power supply, the power supply voltage is 12V or 24V, so if the upper limit of the cooling capacity is set in the operating range when the load is low, the power limit of the cigarette lighter power supply will be exceeded when the load becomes high. For this reason, it is necessary to set the upper limit of the cooling capacity in the operating range when the load is high, which would result in surplus air conditioning capacity when the load is low.

[0006] In particular, in the case of an air conditioner configured to reuse condensed water to cool the condenser in order to improve the coefficient of performance (COP) as in the technology described in Prior Art 1, when time has passed since the start of operation and the condenser begins to be cooled by the generated condensed water, the efficiency of the cooling cycle increases and the required power drops sharply. Even in such a case, from the viewpoint of safety, conventionally, the upper limit of the cooling capacity was set according to the state before the generation of condensed water, that is, the state in which the efficiency of the cooling cycle is low (low efficiency). As a result, there was a problem that the cooling capacity could not be improved even if time had passed since the start of operation and the generation of condensed water had brought the cooling cycle into a high-efficiency state, resulting in a surplus of power.

[0007] In view of the above-mentioned circumstances, the present invention aims to provide an air conditioner that is relatively small in size and has a condenser located below the evaporator, and that is capable of controlling power consumption within the power limit of the power source and making effective use of the air conditioning (cooling) capacity. [Means for solving the problem]

[0008] The present invention relates to an air conditioning apparatus including a housing that houses a refrigerant circuit having a compressor, a condenser, a pressure reducing device, and an evaporator, and a control device, the control device having an operating upper limit value determination unit, a rotation speed command value determination unit, and a compressor rotation control unit, the operating upper limit value determination unit executes control to determine an operating upper limit value that becomes an upper limit rotation speed for driving the compressor in accordance with a load on the compressor, the rotation speed command value determination unit determines a rotation speed command value in accordance with a target blowing temperature and a current rotation speed of the compressor (hereinafter referred to as "current rotation speed") when the load is relatively low, and executes control to determine the current rotation speed or the operating upper limit value as the rotation speed command value when the load is relatively high, and the compressor rotation control unit controls the drive of the compressor based on the rotation speed command value. Effect of the Invention

[0009] According to the present invention, it is possible to provide an air conditioner that is relatively small in size and has a condenser arranged below an evaporator, and that is capable of controlling power consumption within the power limit of the power source and making effective use of the air conditioning (cooling) capacity. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing a schematic configuration of an air conditioning device according to an embodiment of the present invention; [Diagram 2] 1 is a circuit diagram showing a schematic configuration of an air conditioner according to an embodiment of the present invention. [Diagram 3] 1 is a block diagram showing a schematic configuration of a control device for an air conditioner according to an embodiment of the present invention; [Figure 4] 2 is a functional block diagram of a control device for an air conditioner according to the embodiment of the present invention. FIG. [Diagram 5] FIG. 4 is a flowchart showing a flow of a compressor drive control process according to the embodiment of the present invention. [Figure 6] FIG. 11 is a flowchart showing a process flow of an operation upper limit value determination process according to the embodiment of the present invention. [Figure 7] FIG. 4 is a flowchart showing a flow of a command value setting process according to the embodiment of the present invention. [Figure 8] FIG. 11 is a flowchart showing the flow of an upper limit determination process according to the embodiment of the present invention. [Figure 9] 4 is a table showing an example of setting a rotation speed command value according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Figures 1 to 9 show an example of an embodiment of the present invention, in which parts with the same reference numerals indicate parts with the same functions, and duplicated explanations in each figure will be omitted as appropriate.

[0012] <Air conditioner> Fig. 1 is a schematic side view showing a configuration of an air conditioner 100 according to one embodiment of the present invention. Fig. 2 is a schematic circuit diagram illustrating a refrigerant circuit R in the air conditioner 100 of this embodiment.

[0013] 1, the air conditioner 100 is a so-called spot cooler (portable cooler) that uses, for example, a cigarette lighter power supply of a vehicle as a power source and can perform local air conditioning or personal air conditioning of a vehicle cabin or a relatively small space (hereinafter, vehicle cabin, etc.). The air conditioner 100 includes, for example, a condenser 20, a condenser blower 25, a compressor 10, an evaporator 30, an evaporator blower 35, an expansion device (e.g., a capillary tube) not shown in FIG. 1, a control device 50, and a housing 60 that houses these. The housing 60 is provided with, for example, an air outlet 61 that blows air into the vehicle cabin, etc., and an exhaust port 62 of the air conditioner 100.

[0014] The air conditioner 100 is configured such that the condenser 20 is disposed vertically below the evaporator 30 within a single housing 60, and the condensed water generated by the evaporator 30 flows down to the condenser 20. Specifically, for example, a tray (not shown) for receiving the condensed water is provided below the evaporator 30, and a condensed water flow path (not shown) for routing the condensed water as necessary is provided, and the condensed water generated by the evaporator 30 flows down onto the surface (of the tubes) of the condenser 20.

[0015] 2, in the air conditioner 100, a compressor 10, a condenser 20, an expansion device 40, and an evaporator 30 are connected by piping 70. A refrigerant circulates inside the piping 70, thereby forming a refrigerant circuit R in which the refrigerant circulates through the compressor 10, the condenser 20, the expansion device 40, and the evaporator 30 in this order.

[0016] The compressor 10 compresses the refrigerant flowing through the pipe 70. The compressed refrigerant that has become a high-pressure gas is sent to the condenser 20 through the pipe 70. The refrigerant is liquefied in the condenser 20, and the refrigerant that has passed through the condenser 20 is decompressed by the expansion device 40 and sent to the evaporator 30 through the pipe 70.

[0017] The evaporator 30 is a heat exchanger constituting a part of the refrigerant circuit R, and exchanges heat between the air blown from the evaporator blower 35 through an air intake opening (not shown) of the housing 60 and the refrigerant in the main body of the evaporator 30. The air cooled by the heat exchange (cold air) is sent out into the vehicle cabin or the like through an air outlet 61 provided in the housing 60.

[0018] The condenser 20 is a heat exchanger constituting a part of the refrigerant circuit R, and exchanges heat between the air blown from the condenser blower 25 through an air suction opening (not shown) of the housing 60 and the refrigerant in the main body of the condenser 20. The air that has been subjected to the heat exchange is discharged through the exhaust port 62.

[0019] The configuration of the air conditioner 100 is not limited to the example in Fig. 1. For example, a single fan may be provided as an air intake means common to the condenser 20 and the evaporator 30, and the air flow path inside the housing 60 may be branched into a path flowing into the evaporator 30 and a path flowing into the condenser 20. Also, the condenser 20 may be covered with a cover provided with a flow path for condensed water.

[0020] 1 and 2, the air conditioner 100 of this embodiment causes condensed water generated by the evaporator 30 to flow down to the condenser 20. The condensed water is moisture in the air blown from the evaporator blower 35 that is cooled by the heat absorption by the evaporator 30. By reusing this condensed water and causing it to flow down to the condenser 20, the cold energy of the condensed water is recovered by the condenser 20, and the release of heat possessed by the refrigerant flowing inside the tubes of the condenser 20 is promoted. This makes it possible to improve the cooling efficiency in the refrigerant circuit R. The condensed water is evaporated in whole or in part by the heat dissipation from the condenser 20.

[0021] In this embodiment, in the air conditioner 100 capable of improving the cooling efficiency, the cooling capacity can be effectively utilized without being wasted, particularly in an operating range where the cooling efficiency is improved (high efficiency state of the cooling cycle) and / or an operating range where the load on the compressor 10 is low. This will be described below.

[0022] <Control device> Fig. 3 is a block diagram showing an outline of the hardware configuration of the control device 50 that controls the air conditioner 100, and the input / output relationship between the control device 50 and other components of the air conditioner 100. Note that Fig. 3 shows only the main components for explaining this embodiment, and the hardware configuration of the air conditioner 100 and the control device 50 includes known components other than those shown in the figure, but these are not shown in the figure.

[0023] The control device 50 of this embodiment includes a CPU (Central Processing Unit) 51, a memory 52 such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a non-volatile storage unit 53 such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive), and a communication control unit 54. The CPU 51, the memory 52, the storage unit 53, and the communication control unit 54 are connected to each other via an internal bus 55 so as to be able to communicate with each other. The storage unit 53 stores various programs including a compressor drive control program described later.

[0024] Various sensors (detectors) 80, an operation unit 91, etc. are connected to the control device 50, and outputs thereof are inputted thereto. The various sensors 80 include at least a rotation speed detection sensor 81 for detecting the rotation speed of the compressor 10, an outside air temperature sensor 82 for detecting the outside air temperature, an evaporator temperature sensor 84 for detecting the temperature of the evaporator 30 (the temperature of the air that has passed through the evaporator 30, or the temperature of the evaporator 30 itself), a current detection sensor 85 for detecting the current consumption of the compressor 10, and an outlet temperature sensor 86 for detecting the temperature of the air blown out from the outlet 61 into the vehicle cabin.

[0025] The operation unit 91 is composed of, for example, a touch panel, and includes operation means such as a power switch, a cooling switch, and a fan air volume switch, and display means such as power on / off display, cooling on / off display, air volume display, and error display.

[0026] On the other hand, for example, the compressor 10, the condenser blower 25, and the evaporator blower 35 are connected to the output of the control device 50. The control device 50 controls each component of the air conditioner 100 based on the outputs of the various sensors 80 and values ​​(e.g., air volume) inputted through an operation unit 91.

[0027] In FIG. 3, the control device 50 and the various sensors 80 may be integrated into one device, such as a one-chip microcomputer.

[0028] 4 is a block diagram showing a functional configuration of the control device 50. The control device 50 functions as a compressor drive control section 500 that executes drive control of the compressor 10, for example.

[0029] <Compressor drive control unit> The compressor drive control unit 500 includes, for example, a state acquisition unit 501 that acquires the state of the outside air environment, the air conditioner 100, and the compressor 10, an operation upper limit value determination unit 502 that determines an operation upper limit value Rrmax that is the upper limit rotation speed for driving the compressor 10, a rotation speed command value determination unit 503 that determines a command value (rotation speed command value Rc) used for rotation control of the compressor 10, and a compressor rotation control unit 506 that drives and controls the compressor 10 based on the rotation speed command value Rc. The compressor drive control unit 500 updates the operation upper limit value Rrmax and the rotation speed command value Rc at a predetermined period (for example, a 10-second period).

[0030] <Status acquisition section> The status acquisition unit 501 acquires output results of the rotation speed detection sensor 81, the outside air temperature sensor 82, the evaporator temperature sensor 84, the current detection sensor 85, the blowout temperature sensor 86, etc. as the status of the compressor 10. The status acquisition unit 501 acquires these output results by periodic (e.g., every second) interrupt processing, and stores them in the storage unit 53.

[0031] <Upper limit operation value determination unit> The upper limit operation value determination unit 502 determines the load on the compressor 10 according to the state of the compressor 10 acquired by the state acquisition unit 501. Here, the "load on the compressor 10" is, for example, a required value for the compressor 10 to maintain the temperature (target discharge temperature Ttgt) discharged into a space in which the air conditioner 100 is placed, such as a vehicle cabin.

[0032] The upper limit operation value determination unit 502 determines that the load on the compressor 10 is relatively low, for example, when the outdoor air environment is at low temperature and / or low humidity, or when the cooling cycle in the refrigerant circuit R is in a high efficiency state. Hereinafter, the state in which the load on the compressor 10 is relatively low will be referred to as a "low load state."

[0033] Furthermore, the operation upper limit value determination unit 502 determines that the load on the compressor 10 is relatively high, for example, when the outdoor air environment is at high temperature and / or high humidity, or when the cooling cycle in the refrigerant circuit R is in a low-efficiency state. Hereinafter, the state in which the load on the compressor 10 is relatively high will be referred to as a "high load state."

[0034] The load on the compressor 10 can be calculated based on at least one of the outdoor air environment (e.g., outdoor air temperature, outdoor air humidity, etc.), the state of the air conditioning device 100 (e.g., set air volume, condensation water generation state, etc.), and the state of the compressor 10 (e.g., current consumption, etc.).

[0035] In this embodiment, as an example, a high load state or a low load state is determined based on the current consumption of the compressor 10. In detail, the current consumption of the compressor 10 in the current state (present) is calculated and determined with respect to the current upper limit value Irmt of the power source (cigarette lighter power supply). The current upper limit value Irmt of the power source (cigarette lighter power supply) is, for example, a fixed value (10 A in this example) according to the power source voltage (12 V or 24 V) and is stored in the memory unit 53 of the control device 50.

[0036] The low load state is a state in which the compressor 10 has a margin in its capacity and can control the rotation of the compressor 10 (giving priority to comfort) according to the discharge temperature, etc. On the other hand, the high load state is a state in which a certain restriction is imposed on the rotation control of the compressor 10 (priority is given to comfort). In detail, the high load state includes a "high load first state" in which the current consumption current is close to the current upper limit value Irmt and control is required to maintain the rotation speed so that it does not rise above the current (present) rotation speed of the compressor 10 (hereinafter referred to as "current rotation speed Rnow"), and a "high load second state" in which there is almost no difference (margin) from the current upper limit value Irmt and control is required to reduce the current rotation speed in order to reduce the current consumption early. The high load second state can also be said to be an emergency or emergency state.

[0037] The operation upper limit value determination unit 502 calculates the ratio of the current (latest) current consumption acquired by the status acquisition unit 501 to the current upper limit value Irmt (the ratio of the current consumption to the current upper limit value Irmt, hereinafter referred to as the "Irmt ratio"). Then, thresholds (first and second thresholds) are set for the Irmt ratio, and the state of the compressor 10 is determined based on the Irmt ratio. Specifically, when the Irmt ratio is less than the first threshold, the compressor 10 is determined to be in a low load state, when the Irmt ratio is equal to or greater than the first threshold and less than the second threshold, the compressor 10 is determined to be in a first high load state (high load state), and when the Irmt ratio is equal to or greater than the second threshold (up to the current upper limit value Irmt), the compressor 10 is determined to be in a second high load state (high load state). The first threshold is, for example, 90%, and the second threshold is, for example, 95%.

[0038] The operating upper limit value determination unit 502 determines the operating upper limit value Rrmax of the compressor 10 according to the determined load (the state of the compressor 10). Specifically, in the case of a low load state, the operating upper limit value determination unit 502 determines the maximum rotation speed of the compressor 10 to the operating upper limit value Rrmax. The maximum rotation speed is a fixed value that is set in advance (stored in the storage unit 53 of the control device 50) according to a power supply voltage of 12 V or 24 V, and is, for example, 3480 rpm. In addition, in the case of a high load first state, the operating upper limit value determination unit 502 determines the current rotation speed Rnow to the operating upper limit value Rrmax.

[0039] In addition, in the case of the high-load second state, the operation upper limit value determination unit 502 sets the rotation speed obtained by correcting (adding) the current rotation speed Rnow with the first correction value as the operation upper limit value Rrmax. Since it is necessary to reduce the rotation speed early in the high-load second state, the first correction value is, for example, -120 rpm. That is, in the case of the high-load second state, the operation upper limit value determination unit 502 determines a value obtained by subtracting 120 rpm from the current rotation speed Rnow as the operation upper limit value Rrmax. However, in the case of the high-load second state, if the result of correcting the current rotation speed Rnow with the first correction value falls below the minimum rotation speed of the compressor 10, the operation upper limit value determination unit 502 (compressor drive control unit 500) stops the compressor 10. The minimum rotation speed is a fixed value that is set in advance (stored in the storage unit 53 of the control device 50) according to the power supply voltage of 12V or 24V, and is, for example, 2100 rpm.

[0040] <Rotation speed command value determination unit> When the compressor 10 is in a low-load state, the rotation speed command value determination unit 503 is capable of executing control to determine a rotation speed command value Rc in accordance with the target blow-out temperature Ttgt, the actual blow-out temperature Tr detected by the blow-out temperature sensor 86, and the current rotation speed Rnow of the compressor 10, and to determine the current rotation speed Rnow or the upper operating limit value Rrmax as the rotation speed command value Rc when the compressor 10 is in a high-load state.

[0041] Specifically, the rotation speed command value determination unit 503 has a command value setting unit 504 and an upper limit judgment unit 505. In the case of a low load state, the command value setting unit 504 corrects the current rotation speed Rnow with a predetermined correction value according to the difference between the target blow-out temperature Ttgt and the actual blow-out temperature Tr, and sets the value obtained by increasing or decreasing the current rotation speed Rnow or maintaining it as the rotation speed command value Rc. In this case, the correction value is selected from, for example, the second correction value (+120 rpm), the third correction value (+60 rpm), the fourth correction value (±0), and the fifth correction value (-60 rpm).

[0042] The target blowing temperature Ttgt is calculated based on the outside air temperature detected by the outside air temperature sensor 82 by calculating the target blowing temperature difference ΔTt by the following (Equation 1) or (Equation 2), and then calculated by (Equation 3).

[0043] When the outside temperature is below 35°C Target outlet temperature difference ΔTt = Outside air temperature - 20[℃] (Formula 1) When the outside temperature exceeds 35°C Target blowout temperature difference ΔTt=15[℃] (Formula 2) Target outlet temperature Ttgt = outside air temperature - target outlet temperature difference ΔTt [℃] (Formula 3)

[0044] In addition, in the case of the high-load first state, the command value setting unit 504 sets either the current rotation speed Rnow, which is obtained by correcting the current rotation speed Rnow with a correction value (for example, the same value as the fifth correction value) according to the actual blowing temperature Tr and the target blowing temperature Ttgt, and reducing the current rotation speed Rnow, or the current rotation speed Rnow, as the rotation speed command value Rc. Specifically, when it is determined that the actual blowing temperature Tr is lower than the target blowing temperature Ttgt and the temperature difference between the two is a predetermined value (for example, 1°C) or more (hereinafter, this may be referred to as the "high-load first state (low temperature)"), it can be said that even in the high-load state, the compressor 10 has some margin in its capacity. In this case, the fifth correction value (for example, -60 rpm) is added to the current rotation speed Rnow to correct the current rotation speed Rnow (the current rotation speed Rnow is reduced), and the resulting value is set as the rotation speed command value Rc.

[0045] On the other hand, when it is determined that the difference between the actual blowing temperature Tr and the target blowing temperature Ttgt is small or that the actual blowing temperature Tr is higher than the target blowing temperature Ttgt (hereinafter, sometimes referred to as the "high-load first state (non-low temperature)"), the compressor 10 has little capacity to spare, so the current rotation speed Rnow is set as the rotation speed command value Rc to maintain the current state. Moreover, the command value setting unit 504 determines the upper limit operation value Rrmax as the rotation speed command value Rc.

[0046] In addition, in the low load state and the high load first state, the command value setting unit 504 sets the rotation speed command value Rc with the minimum rotation speed of the compressor 10 as the lower limit (replaced with the minimum rotation speed as necessary). In the high load second state, as described above, the upper limit operation value determining unit 502 compares the minimum rotation speed.

[0047] The upper limit determination unit 505 compares the rotation speed command value Rc set by the command value setting unit 504 with the upper limit operational value Rrmax, and ultimately determines the rotation speed command value Rc with the upper limit operational value Rrmax (replacing it with the minimum rotation speed if necessary).

[0048] <Compressor rotation control unit> The compressor rotation control unit 506 controls the drive of the compressor 10 based on the rotation speed command value Rc determined by the rotation speed command value determination unit 503. That is, in this example, the compressor 10 is driven by the rotation speed command value Rc that is updated every 10 seconds.

[0049] <Compressor drive control process> An example of the flow of compressor drive control processing executed by compressor drive control unit 500 will be described with reference to Fig. 5 to Fig. 8. Fig. 5 is a flow diagram showing the flow of compressor drive control processing, Fig. 6 is a flow diagram showing the flow of operational upper limit value determination processing executed by operational upper limit value determination unit 502, Fig. 7 is a flow diagram showing the flow of command value setting processing executed by command value setting unit 504, and Fig. 8 is a flow diagram showing the flow of upper limit determination processing executed by upper limit determination unit 505. do.

[0050] The control device 50 (compressor drive control unit 500) executes compressor drive control by reading out a compressor drive control program from the storage unit 53, expanding it in the memory 52, and executing it by the CPU 51. The control device 50 controls the drive of the compressor 10 based on the outputs of the various sensors 80, etc., to operate the air conditioner 100.

[0051] 5, the compressor drive control process is executed at a predetermined cycle (e.g., every 10 seconds) when the compressor 10 starts operating. A status acquisition unit 501 acquires the status of the compressor 10 from the output results of the rotation speed detection sensor 81, the outside air temperature sensor 82, the evaporator temperature sensor 84, the current detection sensor 85, the blowout temperature sensor 86, etc., by periodic (e.g., every second) interruption process, and stores these values ​​in the storage unit 53.

[0052] First, in step S101, the compressor drive control unit 500 acquires the current consumption current. The consumption current is periodically acquired by the status acquisition unit 501 as the output of the current detection sensor 85, and stored in the storage unit 53. In the following step S103, the compressor drive control unit 500 acquires the current rotation speed Rnow. The current rotation speed Rnow is also periodically acquired by the status acquisition unit 501 as the output of the rotation speed detection sensor 81, and stored in the storage unit 53.

[0053] In step S105, an operational upper limit value determination process is performed to determine an operational upper limit value Rrmax according to the Irmt ratio (state of the compressor 10), and in step S107, a command value setting process is performed to (provisionally) set a rotation speed command value Rc according to the target blow-out temperature Ttgt and the actual blow-out temperature Tr. In step S109, an upper limit determination process is performed. In the upper limit determination process, the rotation speed command value Rc set in step S107 is compared with the operational upper limit value Rrmax, and the rotation speed command value Rc is finally determined.

[0054] In the following step S111, the compressor rotation control unit 506 controls the drive of the compressor 10 based on the rotation speed command value Rc determined by the rotation speed command value determination unit 503, and the process ends.

[0055] <Upper operating limit determination process> Fig. 6 is a flow diagram showing an example of the flow of the operation upper limit determination process in step S105 of Fig. 5. The operation upper limit determination process is executed by the operation upper limit determination unit 502, for example.

[0056] In step S201 of the operation upper limit value determination process, the operation upper limit value determination unit 502 acquires the current upper limit value Irmt of the power source (cigarette lighter power supply), and in step S203 calculates the current consumption of the compressor 10 relative to the current upper limit value Irmt (the ratio of the current consumption current to the current upper limit value Irmt (the proportion of the consumption current to the current upper limit value Irmt, Irmt ratio)). In this example, the current consumption current is acquired in step S101 of the compressor drive control process (FIG. 5).

[0057] In step S205, it is determined whether the Irmt ratio is equal to or greater than a second threshold (95% in this example). If it is less than the second threshold, the process proceeds to step S207, and if it is equal to or greater than the second threshold, the process proceeds to step S213.

[0058] In step S207, it is determined whether the Irmt ratio is equal to or greater than a first threshold (90% in this example). If it is less than the first threshold, the process proceeds to step S209, and if it is equal to or greater than the first threshold, the process proceeds to step S211.

[0059] Step S209 is a step to be proceeded to when the compressor 10 is in a low load state. In this case, the preset maximum rotation speed (in this example, a fixed value of 3480 rpm) is determined as the upper limit operation value Rrmax.

[0060] Step S211 is a step to be proceeded to when the state of the compressor 10 is the high-load first state. In this case, the current rotation speed Rnow acquired in step S103 of the compressor drive control process (FIG. 5) is determined to be the upper limit operation value Rrmax.

[0061] In step S213, which is reached when the Irmt ratio is equal to or greater than the second threshold value in step S205 (i.e., the high-load second state), the current rotation speed Rnow is corrected (added) with the first correction value (-120 rpm) and set as the upper limit Rrmax. In other words, the upper limit Rrmax is the current rotation speed Rnow minus 120 rpm.

[0062] In step S215, it is determined whether the upper limit value Rrmax set in step S213 is equal to or lower than the minimum rotation speed, and if it is equal to or lower than the minimum rotation speed, the process proceeds to step S217, and if it exceeds the minimum rotation speed, the process ends. In step S217, a compressor off control process is performed. The compressor off process is a process separate from the compressor drive control process, and details are omitted. After the compressor 10 is stopped, it is restarted after a predetermined time has elapsed by timer control or the like.

[0063] 7 is a flow diagram showing an example of the flow of the command value setting process in step S107 of the compressor drive control process (FIG. 5). The command value setting process is executed by the command value setting unit 504, for example.

[0064] In step S301 of the command value setting process, command value setting unit 504 acquires the outside air temperature and calculates the target blowing temperature difference ΔTt. The outside air temperature is acquired by state acquisition unit 501 as the output of outside air temperature sensor 82 and is stored in memory unit 53. The target blowing temperature difference ΔTt is calculated by the above-mentioned (Equation 1) or (Equation 2) depending on the outside air temperature. In step S303, command value setting unit 504 calculates the target blowing temperature Ttgt by the above-mentioned (Equation 3).

[0065] In step S305, the actual blowing temperature Tr (the temperature of the air at the air outlet 61) is acquired. The actual blowing temperature Tr is acquired by the state acquisition unit 501 as the output of the blowing temperature sensor 86 and is stored in the storage unit 53.

[0066] In step S307, it is determined whether the actual blowing temperature Tr is equal to or higher than the "target blowing temperature Ttgt+1°C". If the actual blowing temperature Tr is lower than the "target blowing temperature Ttgt+1°C", the process proceeds to step S309, and if the actual blowing temperature Tr is equal to or higher than the "target blowing temperature Ttgt+1°C", the process proceeds to step S323.

[0067] In step S309, it is determined whether the actual blowing temperature Tr is less than the "target blowing temperature Ttgt+1°C" and equal to or greater than the target blowing temperature Ttgt, and if so, proceed to step S321, and if not (if the temperature is less than the target blowing temperature Ttgt), proceed to step S311. In step S311, it is determined whether the actual blowing temperature Tr is less than the target blowing temperature Ttgt and higher than the "target blowing temperature Ttgt-1°C", and if so, proceed to step S313, and if not (if the temperature is less than the "target blowing temperature Ttgt-1°C"), proceed to step S315.

[0068] If the determination in step S311 is "Yes" (if the actual blowing temperature Tr is lower than the target blowing temperature Ttgt but the difference between the two is relatively small), the process proceeds to step S313, where the value of the current rotation speed Rnow is set to the rotation speed command value Rc (corrected using the fourth correction value (±0)), and the process ends.

[0069] If the determination in step S311 is "No" (if the actual blowing temperature Tr is lower than the target blowing temperature Ttgt and the difference between them is relatively large), the process proceeds to step S315, in which the current rotation speed Rnow is corrected (added) with a fifth correction value (-60 rpm) and the resulting value is set as the rotation speed command value Rc. In other words, the value obtained by subtracting 60 rpm from the current rotation speed Rnow is set as the rotation speed command value Rc.

[0070] In step S317, it is determined whether the rotation speed command value Rc set in step S315 is below the minimum rotation speed. If it is below the minimum rotation speed, the process proceeds to step S319, and if it is not below the minimum rotation speed, the process ends.

[0071] In step S319, the minimum rotation speed is reset to the rotation speed command value Rc (replaced with the minimum rotation speed), and the process ends.

[0072] If the determination in step S309 is "Yes" (if the actual blowing temperature Tr is equal to or higher than the target blowing temperature Ttgt and the difference between the two is relatively small), the process proceeds to step S321, in which the current rotation speed Rnow is corrected (added) with the third correction value (+60 rpm) and the resulting value is set as the rotation speed command value Rc. In other words, the value obtained by adding 60 rpm to the current rotation speed Rnow is set as the rotation speed command value Rc.

[0073] If the determination in step S307 is "Yes" (if the actual blow-out temperature Tr is higher than the target blow-out temperature Ttgt and the difference between them is relatively large), the process proceeds to step S323, in which the current rotation speed Rnow is corrected (added) with the second correction value (+120 rpm) and the resulting value is set as the rotation speed command value Rc. In other words, the value obtained by adding 120 rpm to the current rotation speed Rnow is set as the rotation speed command value Rc.

[0074] 8 is a flow diagram showing an example of the flow of the upper limit determination process in step S109 of the compressor drive control process (FIG. 5). The upper limit determination process is executed by the upper limit determination unit 505, for example.

[0075] In step S401, the rotation speed command value Rc set by the command value setting process (FIG. 7) is compared with the upper limit value Rrmax. If the rotation speed command value Rc is equal to or greater than the upper limit value Rrmax, the process proceeds to step S403, where the upper limit value Rrmax is reset to the rotation speed command value Rc (replaced with the upper limit value Rrmax). If the rotation speed command value Rc is below the upper limit value Rrmax, the rotation speed command value Rc is maintained, and the process ends. In one example of the flow of this embodiment, the command value setting process shown in FIG. 7 provisionally changes the rotation speed command value Rc according to the actual blowing temperature Tr and the target blowing temperature Ttgt even in the high load second state, but ultimately, the upper limit determination unit 505 determines the operating upper limit value Rrmax as the rotation speed command value Rc regardless of the difference between the actual blowing temperature Tr and the target blowing temperature Ttgt.

[0076] FIG. 9 is a table showing an example of the rotation speed command value Rc determined as a result of the compressor drive control process of this embodiment.

[0077] In this embodiment, only in the case of a low load state (Irmt ratio<90%) and a high load first state (at low temperature), that is, in the case of a low temperature (actual blowing temperature Tr≦target blowing temperature Ttgt-1° C.) in the high load first state (90%≦Irmt ratio<95%), the rotation speed command value Rc is set by correcting the current rotation speed Rnow by a correction value according to temperature. That is, the rotation speed command value Rc is set with priority given to comfort. Specifically, in the case of a low load state (Irmt ratio<90%), the rotation speed command value Rc is set according to the difference between the actual blowing temperature Tr and the target blowing temperature Ttgt in steps S313, S315, S321, and S323 of the command value setting process (FIG. 7). Also, in the case of a high load first state (at low temperature), the rotation speed command value Rc is set (according to the difference between the actual blowing temperature Tr and the target blowing temperature Ttgt) in step S315. The low load state is a state where the compressor 10 has a margin in its capacity, and the high load first state (at low temperature) is a state where the compressor 10 is in a high load state but the actual blowing temperature Tr is relatively low (lower than the target blowing temperature Ttgt, and the difference between the two is large), and there is a margin for lowering the rotation speed. In these cases, the current rotation speed Rnow is corrected according to the difference between the actual blowing temperature Tr and the target blowing temperature Ttgt, and is set as the rotation speed command value Rc.

[0078] On the other hand, in the high load first state (not at low temperature) shown by gray filling in FIG. 9, that is, in the high load first state and the actual blowing temperature Tr is higher than the "target blowing temperature Ttgt-1°C" and in the high load second state, the result is "no" correction according to temperature, and the operation upper limit value Rrmax or the current rotation speed Rnow (the same value as the operation upper limit value Rrmax in the high load first state (not at low temperature)) becomes the rotation speed command value Rc. Specifically, in the high load first state (not at low temperature) and the high load second state, the rotation speed command value Rc is set by step S321 or step S323 of the command value setting process (FIG. 7), but the rotation speed command value Rc is replaced with the operation upper limit value Rrmax by the upper limit judgment process (FIG. 8). In other words, the correction (control) of the current rotation speed Rrnow according to temperature is not performed as a result, and the rotation speed command value Rc is determined based on the consumption current (Irmt ratio).

[0079] As a result, in a high load state (high load first state or high load second state), the compressor 10 can be operated at the maximum rotation speed within a range that does not exceed the available power of the power source (cigarette lighter power supply), and sufficient cooling capacity can be achieved. On the other hand, in a low load state (normal state), the compressor 10 can be operated at the rotation speed that provides the optimal blowing temperature (the difference between the target blowing temperature Ttgt and the actual blowing temperature Tr becomes small).

[0080] As described above, this embodiment performs different controls in a low load state (and an operating region where the compressor 10 has a margin of capacity even in a high load state) and a high load state (an operating region where the compressor 10 has no margin of capacity, the operating region shaded in gray). In other words, as a result, as shown in Fig. 9, as long as the configuration performs different controls in a state where the compressor 10 has a margin of capacity (for example, at low temperatures in a low load state and a high load state) and a state where the compressor has no margin of capacity, the process is not limited to the processes shown in Figs. 5 to 8.

[0081] In the above embodiment, the normal state and high load state of the compressor 10 are determined by a threshold value (of the Irmt ratio) based on the current consumption. However, this is not limiting, and for example, the outside air temperature and / or the outside air humidity may be detected, and a low load and high efficiency may be determined by a composite determination based on these and the power consumption. For example, the normal state may be determined when the temperature is below a threshold value and / or the humidity is below a threshold value and the Irmt ratio is below a threshold value.

[0082] Furthermore, the air conditioner 100 does not necessarily have to be configured to allow the condensed water generated by the evaporator 30 to flow down to the condenser 20 and recover the cold energy of the condensed water by the condenser 20 (enabling reuse of the condensed water).

[0083] The above-mentioned first to fifth correction values ​​are merely examples and are not limited to the above values. In the above embodiment, the correction value in the first high-load state (low temperature) is the same as the fifth correction value, but they may be different values. The above-mentioned first and second threshold values ​​are merely examples and may be other values.

[0084] Incidentally, the air conditioner 100 of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention. [Explanation of symbols]

[0085] 10 Compressor 20 Condenser 25 Condenser fan 30 Evaporator 35 Evaporator fan 40 Expansion Device 50 Control device 51 CPU 52 Memory 53 Storage section 54 Communication control section 55 Internal Bus 60 Case 61 Air outlet 62 Exhaust port 70 Piping 80 Various sensors (detectors) 81 Rotational speed detection sensor 82 Outside air temperature sensor 84 Evaporator temperature sensor 85 Current detection sensor 86 Air outlet temperature sensor 91 Operation section 100 Air conditioner 500 Compressor drive control unit 501 Status acquisition unit 502 Upper limit operation value determination unit 503 Rotation speed command value determination unit 504 Command value setting unit 505 Upper limit judgment section 506 Compressor rotation control unit Irmt Current upper limit Rc Rotation speed command value Rnow Current RPM Rrmax Upper limit of operation Tr Actual outlet temperature Ttgt Target blowout temperature ΔTt Target outlet temperature difference

Claims

1. The refrigerant circuit includes a compressor, a condenser, a pressure reducing device, and an evaporator. The refrigerant circuit includes a control device. The control device includes: An upper limit operation value determining unit; A rotation speed command value determination unit; A compressor rotation control unit, the operation upper limit value determination unit executes control to determine an operation upper limit value that is an upper limit rotation speed for driving the compressor in accordance with a load on the compressor, The rotation speed command value determination unit is When the load is relatively low, the target blowing temperature and the current rotation speed of the compressor (hereinafter referred to as the "current rotation speed") are ) and when the load is relatively high, the current rotation speed or the operation upper limit value is determined as the rotation speed command value. The compressor rotation control unit controls the drive of the compressor based on the rotation speed command value. An air conditioning device characterized by:

2. The operation upper limit value determination unit determines the state of the compressor as determining whether the load is in a relatively low state (hereinafter referred to as a "low load state"), a first state in which the load is relatively high (hereinafter referred to as a "high load first state"), or a second state in which the load is relatively high and current consumption needs to be reduced (hereinafter referred to as a "high load second state"); determining the upper limit of the operation based on the determined state; 2. An air conditioner according to claim 1.

3. The operation upper limit value determination unit is The maximum rotation speed of the compressor in the low load state is set to the upper operational limit value; In the high-load first state, the current rotation speed is set to the operation upper limit value, a rotation speed that is reduced from the current rotation speed in the high-load second state is set as the operation upper limit value.

3. An air conditioner according to claim 2.

4. The rotation speed command value determination unit, in the low load state, increases or decreases the current rotation speed or maintains the current value according to a difference between the target blowing temperature and the actual blowing temperature, and sets the rotation speed command value as the rotation speed command value.

3. An air conditioner according to claim 2.

5. the rotation speed command value determination unit, in the case of the high-load first state, reduces the current rotation speed when it is determined that the actual blowing temperature is low, and sets the current rotation speed as the rotation speed command value when it is determined that the actual blowing temperature is not low.

3. An air conditioner according to claim 2.

6. The rotation speed command value determiner determines the operation upper limit value as the rotation speed command value in the case of the high-load second state.

3. An air conditioner according to claim 2.

7. The rotation speed command value determination unit determines the rotation speed command value with the operation upper limit value as an upper limit.

6. An air conditioner according to claim 4 or 5.

8. The control device stops the compressor when the operation upper limit value determined in the high-load second state falls below a minimum rotation speed of the compressor.

3. An air conditioner according to claim 2.

9. the rotation speed command value determination unit, when the rotation speed command value set in the high-load first state or the low-load state falls below a minimum rotation speed of the compressor, determines the minimum rotation speed as the rotation speed command value.

3. An air conditioner according to claim 2.

10. The condenser is disposed below the evaporator, and condensed water generated by the evaporator is caused to flow down to the condenser.

2. An air conditioner according to claim 1.

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