Air conditioning system and control method for the air conditioning system

Abstract

The air conditioning system disclosed herein enables the rapid discharge of residual air in the complex refrigerant circuits of a vehicle. [Solution] The air conditioning system has an engine, a predetermined air conditioning unit, a first heat exchanger, and a second heat exchanger arranged in parallel. When refrigerant is injected, a first mode is performed in which a four-way switching valve is controlled to open the second and third passages. After the first mode is performed, a second mode is performed in which the four-way switching valve is controlled to open the first and third passages, and a third mode is performed in which the four-way switching valve is controlled to open the first and fourth passages. The control unit controls the system to switch between these modes and repeat the process.

Description

Technical Field

[0001] The present disclosure relates to an air conditioning system.

Background Art

[0002] Patent Document 1 discloses a technique for coordinating battery cooling and defrosting functions of a vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a plug-in hybrid vehicle (PHEV), a complex refrigerant circuit configuration is adopted in which a refrigerant circuit responsible for cooling the engine and a refrigerant circuit responsible for cooling the battery of the air conditioning unit coexist. In such a complicated refrigerant circuit, air is likely to remain in the piping when replenishing or replacing the refrigerant, and the working time may be prolonged. Therefore, there is room for improvement in the control of the refrigerant circuit.

[0005] An object of the present disclosure is to provide an air conditioning system and a control method for the air conditioning system that can discharge residual air in a short time in a complicated refrigerant circuit of a vehicle.

Means for Solving the Problems

[0006] The air conditioning system according to claim 1 comprises a refrigerant circuit and a control unit for controlling a four-way directional control valve, wherein the refrigerant circuit comprises an engine, a predetermined air conditioning unit, a first heat exchanger, and a second heat exchanger arranged in parallel, and includes a water pump and the four-way directional control valve, wherein the engine and the first heat exchanger are located upstream of the refrigerant circuit, and the air conditioning unit and the second heat exchanger are located downstream of the circuit, the water pump and the four-way directional control valve are provided symmetrically downstream, and the refrigerant circuit comprises a first heat exchanger connecting the engine and the first heat exchanger and the four-way directional control valve. The system has a first flow path, a second flow path connecting the water pump and the four-way switching valve, a third flow path connecting the air conditioning unit and the four-way switching valve, and a fourth flow path connecting the second heat exchanger and the four-way switching valve. The control unit performs a first mode in which it controls the four-way switching valve to open the second and third flow paths when refrigerant is injected. After performing the first mode, it switches between a second mode in which it controls the four-way switching valve to open the first and third flow paths, and a third mode in which it controls the four-way switching valve to open the first and fourth flow paths, and repeats the process. This enables the discharge of residual air in a short time in the complex refrigerant circuit of a vehicle.

[0007] The air conditioning system according to claim 2 is the air conditioning system according to claim 1, wherein the control unit controls the output of the water pump to be kept at a low output until the transition from the first mode to the second mode, and then switches to a high output when switching from the second mode to the third mode. The air conditioning system according to claim 2 can prevent the blowing out of cooling water. [Effects of the Invention]

[0008] The technology disclosed herein enables the rapid discharge of residual air from the complex refrigerant circuits of vehicles. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a diagram showing the configuration of the air conditioning system of this embodiment. [Figure 2] Figure 2 shows an example of flow path switching by mode control of a four-way switching valve. [Figure 3] Figure 3 shows an example of flow path switching by mode control of a four-way switching valve. [Figure 4] Figure 4 shows an example of flow path switching by mode control of a four-way switching valve. [Figure 5] Figure 5 shows an example of a time chart for mode control. [Figure 6] Figure 6 is a flowchart illustrating the processing flow of this embodiment. [Modes for carrying out the invention]

[0010] An overview of embodiments of the present invention will now be described. Recently, the complexity of cooling drain pipes has been increasing in electric vehicles, especially PHEVs. In PHEVs, the addition of an engine has made the refrigerant circuit system more complex, with multiple branching and merging points in the pathways. Therefore, compared to BEVs, more cooling water needs to be injected into the complex flow paths. In such complex systems, there is a problem that the water injection is poor, the injection takes a long time, and air bubbles tend to remain. In addition, the flow paths bend vertically, and there is a problem that air bubbles tend to remain in the upward-protruding parts. If air bubbles remain in the system during water injection, it leads to a decrease in heating performance, engine cooling performance, and an increase in the failure rate of parts. Also, when the water pump is operated to switch the flow path during water injection, fluctuations in water flow resistance can cause cooling water to spray out from the inlet. Due to these various problems, it is difficult to expel internal air when injecting cooling water into the piping, resulting in increased working time and a decrease in cooling performance.

[0011] Therefore, in this embodiment, we propose an air conditioning system relating to a control method for a water pump and a water circuit switching valve (four-way switching valve) so that the internal air can be efficiently discharged. The air conditioning referred to here is air conditioning for controlling the discharge of air (residual air) in the refrigerant circuit.

[0012] Figure 1 shows the configuration of the air conditioning system 10 of this embodiment. As shown in Figure 1, the air conditioning system 10 is connected to a refrigerant circuit 100 and a vehicle ECU 120 for controlling the refrigerant circuit 100. The vehicle ECU 120 is an example of the control unit of this disclosure.

[0013] The refrigerant circuit 100 comprises an inlet 102, a water pump 104, a four-way switching valve 106, an engine 110, a predetermined air conditioning unit (HVAC: Heating Ventilation and Air Conditioning) called HVAC 112, a first heat exchanger 114, and a second heat exchanger 116. The HVAC 112, the first heat exchanger 114, and the second heat exchanger 116 are arranged in parallel, with the engine 110 and the first heat exchanger 114 located in the upstream path (a) of the circuit, and the HVAC 112 and the second heat exchanger 116 located in the downstream path (b) of the circuit. Further downstream, the water pump 104 and the four-way switching valve 106 are symmetrically arranged and connected to the vehicle ECU 120.

[0014] The vehicle ECU120 is implemented as a computer with a hardware configuration that includes a CPU (Central Processing Unit), ROM (Read Only Memory) which stores programs for various processes, RAM (Random Access Memory) which temporarily stores data, memory as a means of storage, and a network interface.

[0015] The water pump 104 is an electrically operated pump controlled by the vehicle ECU 120. The four-way switching valve 106 is a switching valve controlled by the vehicle ECU 120 that can switch the flow path when refrigerant is injected.

[0016] The water injection process of the refrigerant circuit will be described. Upon receiving a trigger for starting water injection from outside the vehicle, the water pump 104 is activated. The trigger is received from a navigation operation on the vehicle ECU 120 or a connected connector. After the operation of the water pump 104, cooling water is replenished from the injection port 102 (refrigerant water injection). As a result, the cooling water is injected from the upstream. The flow path of the refrigerant circuit is switched by the four-way switching valve 106. Here, the water pump 104 and the four-way switching valve 106 are controlled in cooperation to prevent ejection.

[0017] In the refrigerant circuit 100, when water is injected from the injection port 102, the water pump 104 is operated to flush air bubbles toward the injection port 102. By switching the cooling water flow path, the amount of water flowing through the flow path can be increased, and air bubbles can be discharged more efficiently. Also, when the flow path branches, the water divides and flows, resulting in a decrease in the flow velocity and a reduction in the air bubble discharge performance.

[0018] In the air conditioning system 10 of the present embodiment, the flow path is switched by mode control. FIGS. 2 to 4 are examples of switching the flow path by mode control of the four-way switching valve. FIG. 2 illustrates the first mode, FIG. 3 illustrates the second mode, and FIG. 4 illustrates the third mode. As the flow paths of the refrigerant circuit, a first flow path (a1), a second flow path (a2), a third flow path (a3), and a fourth flow path (a4) are shown. The first flow path (a1) is a flow path connecting the engine 110, the first heat exchanger 114, and the four-way switching valve 106. The second flow path (a2) is a flow path connecting the water pump 104 and the four-way switching valve 106. The flow path in which the four-way switching valve 106 is closed is in a state where the cooling water (refrigerant) is blocked.

[0019] The vehicle ECU 120 controls the four-way switching valve 106 to repeatedly switch between and execute the second mode and the third mode after executing the first mode.

[0020] In the first mode, when injecting refrigerant, the four-way switching valve 106 is controlled to open the second flow path (a2) and the third flow path (a3). In this case, the upstream side is blocked, but the downstream side is switched so that the refrigerant flows from the second flow path (a2) to the third flow path (a3). Next, after the first mode is implemented, the vehicle ECU 120 controls to switch between the second mode and the third mode and repeat the implementation. In the second mode, the four-way switching valve 106 is controlled to open the first flow path (a1) and the third flow path (a3). Similarly, it is assumed that the fourth flow path (a4) is opened from the second flow path (a2). In this case, the flow is switched so that it flows from the first flow path (a1) on the upstream side to the third flow path (a3), and from the second flow path (a2) to the fourth flow path (a4). In the third mode, the four-way switching valve 106 is controlled to open the first flow path (a1) and the fourth flow path (a4). In this case, the downstream side is switched so that the refrigerant flows from the first flow path (a1) to the fourth flow path (a4). In the third mode, as for the flow, since the second flow path (a2) and the third flow path (a3) on the inner side of the downstream side are blocked, the flow from the upstream side becomes a flow that returns upstream through the second heat exchanger 116 and the water pump 104.

[0021] By switching through mode control as described above, it is possible to discharge the residual air by repeating the phase of blocking the flow path to store air and the phase of opening the flow path to discharge air.

[0022] Fig. 5 shows an example of a time chart of mode control. After implementing the first mode, it shifts to the second mode and the third mode, and then the switching between the second mode and the third mode is repeated. Regarding the output level of the water pump 104, the vehicle ECU 120 sets the output to Low (low output) until shifting from the first mode to the second mode, and then switches the output to Higth (high output) when switching from the second mode to the third mode. Thereby, the blowing out of the cooling water can be prevented.

[0023] (Flow of control) Fig. 6 is a flowchart for explaining the flow of the process of this embodiment.

[0024] In step S100, the vehicle ECU 120 receives a trigger and activates the water pump 104.

[0025] In step S102, the vehicle ECU 120 starts injecting refrigerant and performs the first mode of the four-way switching valve 106. The first mode opens the second passage (a2) and the third passage (a3).

[0026] In step S104, the vehicle ECU 120 gradually transitions the mode of the four-way switching valve 106 from the first mode to the second mode and then to the third mode. In the second mode, the first passage (a1) and the third passage (a3) ​​are opened, and in the third mode, the first passage (a1) and the fourth passage (a4) are opened.

[0027] In step S106, the vehicle ECU 120 controls the four-way switching valve 106 to repeatedly switch between the second mode and the third mode. This repetition is performed for a predetermined time or until residual air is detected to be discharged.

[0028] As described above, this embodiment enables the rapid discharge of residual air in the complex refrigerant circuit of a vehicle.

[0029] Furthermore, after injecting water into the upstream path (a) where the engine 110 is located, the flow path of the refrigerant circuit 100 is switched while operating the water pump 104. This allows air to be discharged by flowing water through the downstream path where air bubbles are less likely to escape. In addition, the vehicle ECU 120 automatically controls the switching of the flow path, thereby reducing the working time.

[0030] In addition, the various processes that the CPU reads and executes in the above embodiment may be executed by various processors other than the CPU. Examples of such processors include PLDs (Programmable Logic Devices) such as FPGAs (Field-Programmable Gate Arrays) whose circuit configuration can be changed after manufacturing, GPUs (Graphics Processing Units), and ASICs (Application Specific Integrated Circuits), which are dedicated electrical circuits that have a circuit configuration specifically designed to execute a particular process. Furthermore, each of the above processes may be executed by one of these various processors, or by a combination of two or more processors of the same or different types (for example, multiple FPGAs, and a combination of a CPU and an FPGA). More specifically, the hardware structure of these various processors is an electrical circuit that combines circuit elements such as semiconductor elements.

[0031] Furthermore, in the above embodiment, the information processing program was described as being pre-stored (installed) on a non-temporary recording medium that can be read by a computer. For example, the information processing program is pre-stored on ROM or storage. However, it is not limited to this, and each program may be provided in a form recorded on a non-temporary recording medium such as a CD-ROM (Compact Disc Read Only Memory), DVD-ROM (Digital Versatile Disc Read Only Memory), and USB (Universal Serial Bus) memory. Alternatively, the information processing program may be downloaded from an external device via a network.

[0032] The processing flow described in the above embodiment is just one example, and unnecessary steps may be deleted, new steps added, or the processing order rearranged, as long as it does not deviate from the main purpose. [Explanation of symbols]

[0033] 10. Air conditioning system 100 Refrigerant Circuit 102 Inlet 104 Water pump 106 4-way switching valve 110 engine 112 HVAC (Air Conditioning Unit) 114 1st heat exchanger 116 Second heat exchanger 120 Vehicle ECU (Control Unit)

Claims

1. It has a refrigerant circuit and a control unit that controls a four-way switching valve, The refrigerant circuit comprises an engine, a predetermined air conditioning unit, a first heat exchanger, and a second heat exchanger arranged in parallel, and includes a water pump and the four-way switching valve. The refrigerant circuit is configured such that the engine and the first heat exchanger are located upstream of the circuit, the air conditioning unit and the second heat exchanger are located downstream of the circuit, and the water pump and the four-way switching valve are symmetrically located downstream. The refrigerant circuit has a first flow path connecting the engine and the first heat exchanger and the four-way control valve, a second flow path connecting the water pump and the four-way control valve, a third flow path connecting the air conditioning unit and the four-way control valve, and a fourth flow path connecting the second heat exchanger and the four-way control valve. The control unit performs a first mode in which it controls the four-way switching valve to open the second and third passages when injecting refrigerant water, and after performing the first mode, it switches between a second mode in which it controls the four-way switching valve to open the first and third passages, and a third mode in which it controls the four-way switching valve to open the first and fourth passages, and repeats the process. Air conditioning system.

2. The air conditioning system according to claim 1, wherein the control unit controls the output of the water pump to be kept at a low output until the transition from the first mode to the second mode, and then switches to a high output when switching from the second mode to the third mode.

3. A control method for an air conditioning system that controls a refrigerant circuit and a control unit that controls a four-way switching valve, The refrigerant circuit comprises an engine, a predetermined air conditioning unit, a first heat exchanger, and a second heat exchanger arranged in parallel, and includes a water pump and the four-way switching valve. The refrigerant circuit is configured such that the engine and the first heat exchanger are located upstream of the circuit, the air conditioning unit and the second heat exchanger are located downstream of the circuit, and the water pump and the four-way switching valve are symmetrically located downstream. The refrigerant circuit has a first flow path connecting the engine and the first heat exchanger to the four-way control valve, a second flow path connecting the water pump to the four-way control valve, a third flow path connecting the air conditioning unit to the four-way control valve, and a fourth flow path connecting the second heat exchanger to the four-way control valve. The control unit performs a first mode in which it controls the four-way switching valve to open the second and third passages when injecting refrigerant water, and after performing the first mode, it switches between a second mode in which it controls the four-way switching valve to open the first and third passages, and a third mode in which it controls the four-way switching valve to open the first and fourth passages, and repeats the process. A method for controlling an air conditioning system.

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