Vehicle-mounted air conditioning system

Abstract

Disclosed is a vehicle-mounted air-conditioning system capable of quickly cooling the interior of a vehicle with high energy efficiency. This vehicle-mounted air conditioning system is provided with: an air conditioning device that is mounted on a vehicle and that can be switched between an inside air circulation mode and an outside air introduction mode; and a controller that, during a cooling operation, causes the air conditioning device to perform a cooling operation in the outside air introduction mode when an in-vehicle temperature is higher than an outside air temperature, and causes the air conditioning device to perform a cooling operation in the outside air introduction mode when a temperature difference between the in-vehicle temperature and the outside air temperature is equal to or less than a predetermined reference value even if the in-vehicle temperature is higher than the outside air temperature. And the air conditioning device is also switched into the internal air circulation mode.

Description

Technical Field

[0001] This specification discloses an air conditioning system installed in a vehicle. Background Technology

[0002] Vehicles are typically equipped with air conditioning systems. These systems regulate the temperature of the air by compressing, expanding, condensing, and evaporating the refrigerant during refrigerant circulation, and then deliver the regulated air into the vehicle to adjust the interior temperature.

[0003] The air conditioning system can switch between an internal air recirculation mode (circulating the air inside the vehicle) and an external air intake mode (introducing outside air). Unless specifically instructed by the passenger, the vehicle's air conditioning system typically operates in internal air recirculation mode. This is because internal air recirculation mode is generally more energy efficient than external air intake mode.

[0004] However, under certain conditions, the energy efficiency of the external air intake mode is higher than that of the internal air recirculation mode. Therefore, the proposal includes a technology that can forcibly stop the cooling operation in the internal air recirculation mode under certain conditions.

[0005] For example, Patent Document 1 discloses a technology in which, when the interior temperature of a vehicle is higher than the exterior temperature, outdoor air is introduced into the vehicle for ventilation before the cooling operation begins. According to this technology, compared to cooling operation in an internal air recirculation mode, the interior temperature can be reduced with less energy.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-154842 Summary of the Invention However, the technology in Patent Document 1 only ventilates the vehicle interior when the interior temperature is higher than the exterior temperature. In this case, time is required for the interior temperature to drop sufficiently. In particular, in recent years, considering the global environment, proposals have included air conditioning systems that use CO2 refrigerant, primarily composed of carbon dioxide (hereinafter referred to as "CO2"), instead of fluorinated refrigerants. Compared to air conditioning systems using fluorinated refrigerants, this system has lower cooling efficiency. Therefore, as in Patent Document 1, when only ventilation is performed inside the vehicle, the time required for the interior to cool down sufficiently increases.

[0007] Therefore, this specification discloses an in-vehicle air conditioning system capable of rapidly cooling the vehicle interior with high energy efficiency.

[0008] This specification discloses a vehicle air conditioning system, characterized in that it comprises: an air conditioning unit mounted on a vehicle, capable of switching between an internal air recirculation mode and an external air intake mode; and The controller, when operating in cooling mode, causes the air conditioning unit to operate in the outside air intake mode when the interior temperature is higher than the outside air temperature. If the temperature difference between the interior temperature and the outside air temperature is below a specified reference value, the air conditioning unit will switch to the internal air recirculation mode even if the interior temperature is higher than the outside air temperature.

[0009] By designing the structure in this way, the interior of the vehicle can be cooled quickly and efficiently.

[0010] In this case, the air conditioning unit can circulate a refrigerant with CO2 as its main component.

[0011] Using CO2 refrigerant can reduce the burden on the environment. Furthermore, while CO2 refrigerant has lower cooling efficiency compared to fluorinated refrigerants, it can still provide adequate cooling when the vehicle interior temperature is high by implementing an outside air intake mode.

[0012] Furthermore, it can be as follows: it also has a CO2 sensor for detecting the CO2 concentration inside the vehicle, and when the CO2 concentration detected by the CO2 sensor is above a predetermined reference threshold, the controller switches to the outside air introduction mode regardless of temperature.

[0013] By designing the structure in this way, proper ventilation can be maintained even in the event of a CO2 refrigerant leak for some reason.

[0014] Furthermore, it can be as follows: when the passenger specifies either the internal air recirculation mode or the external air intake mode, the controller causes the air conditioning unit to operate in the specified mode for cooling, regardless of the interior temperature and the outside air temperature.

[0015] By configuring the structure in this way, the cooling operation desired by the flight attendants can be performed.

[0016] Furthermore, it can be as follows: after the controller starts the cooling operation and implements the internal air circulation mode once, it will not use the situation that the temperature inside the vehicle is higher than the temperature outside the vehicle as a trigger condition to switch modes until the cooling operation is stopped.

[0017] By designing the structure in this way, the interior temperature can be quickly reduced even when the temperature inside the car is excessively high, such as during a summer day.

[0018] Invention Effects According to the technology disclosed in this specification, the vehicle interior can be cooled quickly and efficiently. Attached Figure Description

[0019] Figure 1It is a block diagram representing the structure of an air conditioning system.

[0020] Figure 2 This is the circuit diagram of an air conditioning unit.

[0021] Figure 3 It is a flowchart representing the control process of switching between indoor and outdoor air during refrigeration operation. Detailed Implementation

[0022] The structure of the air conditioning system 10 will be described below with reference to the accompanying drawings. Figure 1 This is a block diagram showing the structure of the air conditioning system 10. Furthermore, Figure 2 This is a circuit diagram of the air conditioning unit 12. The air conditioning system 10 is installed in the vehicle and adjusts the temperature inside the vehicle. Furthermore, there is no particular limitation on the type of vehicle equipped with the air conditioning system 10. Therefore, the vehicle can be an engine-powered automobile or an electric vehicle powered by a motor. Moreover, the vehicle can be a hybrid electric vehicle equipped with both an engine and a motor, a fuel cell vehicle equipped with a fuel cell, or a battery electric vehicle that runs on electricity stored in a battery.

[0023] like Figure 1 As shown, the air conditioning system 10 includes an air conditioning unit 12, a controller 14, and a CO2 sensor 20. The air conditioning unit 12 regulates the temperature inside the vehicle. During the refrigerant circulation process, the air conditioning unit 12 controls the temperature of the air supplied to the vehicle by compressing, expanding, condensing, and evaporating the refrigerant. In this example, the air conditioning unit 12 uses CO2 refrigerant, with CO2 as its main component. The air regulated by the air conditioning unit 12 is supplied to the vehicle through a blower 38. Furthermore, the indoor / outdoor air switching door 44, which will be described in detail later, is a door that switches between the air inlets 43a and 43b in the air conditioning unit 12. By changing the position of the indoor / outdoor air switching door 44, the operating mode of the air conditioning unit 12 switches between an indoor air recirculation mode and an outdoor air intake mode.

[0024] CO2 sensor 20 detects the CO2 concentration inside the vehicle. CO2 sensor 20 can be installed inside the vehicle or near the blower 38 of the air conditioning unit 12. In short, CO2 sensor 20 is positioned to detect CO2 refrigerant leaks at an early stage. Furthermore, CO2 sensor 20 is not limited to one; multiple sensors can be installed. The CO2 concentration detected by CO2 sensor 20 is sent as the detection concentration to controller 14.

[0025] Controller 14 controls the drives of the aforementioned components. This controller 14 is physically a computer with a processor 16 and a memory 18. Furthermore, in Figure 1In the illustration, controller 14 is shown as a single computer, but controller 14 can also be configured as a combination of multiple physically separate computers.

[0026] Next, the structure of the air conditioning unit 12 will be described. The air conditioning unit 12 has a refrigerant circuit 30. The refrigerant circuit 30 is a circuit that generates heat and latent heat by compressing, expanding, condensing, and evaporating the refrigerant during its circulation. The heat generated in this refrigerant circuit 30 is used for heating, and the latent heat is used for cooling. Conventionally, fluorinated refrigerants have been widely used. However, fluorinated refrigerants have a high environmental impact. Therefore, in this example, as repeatedly stated, CO2 refrigerant, with CO2 as its main component, is used. Compared to fluorinated refrigerants, CO2 refrigerant has a lower warming coefficient and a lower environmental impact.

[0027] The refrigerant circuit 30 has a refrigerant piping 31 for supplying CO2 refrigerant. Along the path of this refrigerant piping 31 are a compressor 32, a gas cooler 34, a liquid accumulator 52, a refrigeration expansion valve 46, and an evaporator 48. The compressor 32 compresses the gaseous CO2 refrigerant. The gas cooler 34 is a heat exchanger that allows the CO2 refrigerant to exchange heat with the outside air. During refrigeration operation, the gas cooler 34 functions as a condenser to condense the gaseous CO2 refrigerant. A fan 36 is located behind the gas cooler 34 for efficiently drawing in outside air.

[0028] The accumulator 52 performs gas-liquid separation of the CO2 refrigerant, sending only the gaseous CO2 refrigerant to the compressor 32. Furthermore, in... Figure 1 In this example, the accumulator 52 has a main body 54 for gas-liquid separation of CO2 refrigerant and a heat exchanger 56 disposed around the main body 54. The dissipated CO2 refrigerant output from the gas cooler 34 flows through the heat exchanger 56 toward the refrigeration expansion valve 46. During its flow through the heat exchanger 56, the dissipated CO2 refrigerant exchanges heat with the gas-liquid mixed CO2 refrigerant stored in the main body 54. The dissipation of heat from the CO2 refrigerant in the heat exchanger 56 to the CO2 refrigerant in the main body 54 promotes the vaporization of the CO2 refrigerant in the main body 54.

[0029] The expansion valve 46 for refrigeration is a solenoid valve that performs throttling control during refrigeration operation and is completely closed during heating operation. When the expansion valve 46 for refrigeration is throttling controlled, the CO2 refrigerant is rapidly depressurized as it passes through the expansion valve 46. The evaporator 48 is an evaporator that evaporates liquid CO2 refrigerant and is disposed in the airflow path of the air conditioning unit housing 64. The air surrounding the evaporator 48 is cooled by the latent heat generated during evaporation.

[0030] And, although in Figure 2Although not shown in the diagram, multiple solenoid valves for switching the flow direction of CO2 refrigerant are provided in the refrigerant circuit 30. Furthermore, multiple PT sensors 50 are configured in the refrigerant circuit 30 to detect the pressure and temperature of the CO2 refrigerant flowing in the refrigerant piping 31.

[0031] An air outlet mechanism 62 is installed inside the vehicle. The air outlet mechanism 62 is a mechanism that cools or heats air drawn in from outside or inside the vehicle and blows it into the vehicle. This air outlet mechanism 62 includes a unit housing 64, a blower 38, and a heater core 40. At the upstream end of the unit housing 64 are provided air inlets 43a and 43b, which are separated in two directions, and an inside / outside air switching door 44. One air inlet 43a communicates with the inside of the vehicle, and the other air inlet 43b communicates with the outside of the vehicle. Therefore, by changing the position of the inside / outside air switching door 44, the communication destination of the unit housing 64 is switched between inside and outside the vehicle. Furthermore, this switches the air conditioning mode of the air conditioning unit 12 between an internal air recirculation mode and an external air intake mode.

[0032] Furthermore, in the outside air intake mode, when the blower 38 is driven, the interior is forcibly ventilated, but the cooling and heating efficiency decreases. Therefore, except in specific cases, the controller 14 generally operates the air conditioning unit 12 in the internal air recirculation mode. Specific cases include situations where the outside air intake mode is specified by the passenger and situations where the interior temperature exceeds the outside air temperature during cooling operation.

[0033] An outlet (not shown) for directing air conditioning air into the vehicle is formed at the downstream end of the unit housing 64. An evaporator 48 and a heater core 40 are disposed within the unit housing 64. During cooling operation, the evaporator 48 cools the air delivered from the blower 38 using the latent heat of refrigerant vaporization. The cooled air conditioning air is then delivered into the vehicle, thus cooling the interior.

[0034] The heater core 40 is heated by other heat sources during heating operation. These other heat sources can be, for example, an engine or an electric heater. The heater core 40 is heated directly or indirectly via a refrigerant such as water. A heating / cooling switching door 42 is located upstream of the heater core 40. The heating / cooling switching door 42 regulates the airflow through the heater core 40. During heating operation, the heating / cooling switching door 42 moves to a position that does not obstruct the airflow towards the heater core 40. Figure 2 (The position of the dotted line in the diagram). Thus, the air delivered from the blower 38 is heated by the heater core 40. The heated air is then output to the vehicle interior, providing heating.

[0035] As described above, the air conditioning unit 12 in this example can switch between internal air recirculation mode and external air intake mode. Compared to internal air recirculation mode, the cooling and heating efficiency of external air intake mode is reduced. Therefore, unless specifically instructed by the user, the air conditioning unit 12 usually operates in internal air recirculation mode. However, under certain conditions, the cooling and heating efficiency of external air intake mode is sometimes higher than that of internal air recirculation mode. Specifically, when the interior temperature Tin is higher than the exterior temperature Tout, the cooling and heating efficiency, and thus the energy efficiency, of external air intake mode is more likely to be higher than that of internal air recirculation mode. In particular, during the daytime in summer, the interior temperature Tin of a vehicle parked outdoors is significantly higher than that of the exterior temperature Tout. For example, when the exterior temperature Tout is around 35°C, the interior temperature Tin of a vehicle parked outdoors can sometimes reach over 50°C. Under such temperature differences, the energy efficiency is extremely poor when operating in internal air recirculation mode for cooling.

[0036] Therefore, in this example, during cooling operation, when the interior temperature Tin is higher than the outside air temperature Tout, the outside air intake mode is selected. See below for reference. Figure 3 These controls are explained. Figure 3 It is a flowchart representing the control process of switching between indoor and outdoor air during refrigeration operation.

[0037] like Figure 3 As shown, when the cooling operation begins, the controller 14 confirms whether the user has given an instruction to switch between internal and external air (S10). If the user specifies an internal air recirculation mode or an external air intake mode, the cooling operation is performed in the specified mode (S12). For example, if the user specifies an external air intake mode, the cooling operation is performed in the external air intake mode regardless of the vehicle interior temperature Tin and the external air temperature Tout.

[0038] On the other hand, if the user does not specify an internal / external air switching mode, the controller 14 performs automatic operation to automatically select the internal / external air switching mode on the vehicle side. In this case, the controller 14 first compares the interior temperature Tin and the outside air temperature Tout (S14). If the comparison result shows that the interior temperature Tin is lower than the outside air temperature Tout, the cooling operation is performed in internal air recirculation mode (S20). By not introducing outside air temperature Tout, which is higher than the interior temperature Tin, into the vehicle, the cooling of the vehicle interior can be performed more efficiently.

[0039] On the other hand, in step S14, when the interior temperature Tin is higher than the outside air temperature Tout, the controller 14 operates in the outside air intake mode for cooling (S16). In this case, since outside air, which is cooler than the interior temperature, is introduced into the vehicle, the interior temperature drops rapidly. Furthermore, since cooling based on the air conditioning unit 12 is performed in parallel with the introduction of the low-temperature outside air (i.e., ventilation), the interior temperature drops even more rapidly.

[0040] Then, the controller 14 periodically compares the temperature difference ΔT between the interior temperature Tin and the outside air temperature Tout with a predefined reference difference ΔTst (S18). Furthermore, if the temperature difference ΔT falls below the reference difference ΔTst ("No" in S18), the controller 14 switches from the outside air intake mode to the interior air recirculation mode. As a result, the cooling efficiency is further improved.

[0041] In other words, if the outside air temperature (Tout) is close to the inside air temperature (Tin), and the outside air intake mode continues, outside air will constantly flow into the vehicle, thus requiring time for the inside air temperature (Tin) to drop below the outside air temperature (Tout). Conversely, when the temperature difference (ΔT) becomes relatively small, switching to internal air recirculation mode to block the inflow of outside air can efficiently reduce the inside air temperature (Tin) and improve energy efficiency.

[0042] After switching to recirculation mode, it will generally remain in recirculation mode. In other words, if recirculation mode is executed once after cooling operation begins, the mode will not switch again if the interior temperature Tin is higher than the outside air temperature Tout. This is for the following reasons.

[0043] If the cabin temperature Tin drops sufficiently and the recirculation mode is activated, a significant increase in the cabin temperature Tin compared to the outside air temperature Tout is unlikely. Furthermore, as mentioned above, when the temperature difference ΔT is small, the recirculation mode is more energy-efficient than the outside air intake mode. Therefore, after switching to recirculation mode, even if Tout < Tin, switching back to outside air intake mode will not be performed. However, if the crew instructs switching to outside air intake mode after starting operation in recirculation mode, then switching to outside air intake mode will occur. Moreover, if high energy efficiency can be maintained sufficiently, after switching to recirculation mode, if the cabin temperature Tin is significantly higher than the outside air temperature Tout, switching back to outside air intake mode is permissible.

[0044] As explained above, in this example, at the start of the cooling operation, when the interior temperature Tin is higher than the outside air temperature Tout, the cooling operation is performed in outside air intake mode. This allows for rapid and efficient cooling of the vehicle interior.

[0045] Furthermore, in the above description, the switching between internal and external gases is based on temperature. However, in addition to temperature, the switching between internal and external gases can also be based on the CO2 concentration detected by the CO2 sensor 20.

[0046] That is, as repeatedly stated, the air conditioning unit 12 in this example uses CO2 refrigerant, which is mainly composed of CO2, as the refrigerant. In this case, if CO2 leaks into the vehicle due to a break in the refrigerant pipe 31 for some reason, the CO2 concentration inside the vehicle will increase. In this case, rapid ventilation is required. Therefore, the controller 14 can monitor the CO2 concentration detected by the CO2 sensor 20, and when the CO2 concentration exceeds a predetermined reference threshold, it will always switch to the outside air introduction mode regardless of the temperature Tin or Tout. Furthermore, while the example of an air conditioning unit 12 using CO2 refrigerant has been described so far, the technology disclosed in this specification can also be applied to air conditioning units 12 using other types of refrigerants, such as fluorinated refrigerants or propane refrigerants.

[0047] Symbol Explanation 10-Air conditioning system, 12-Air conditioning unit, 14-Controller, 16-Processor, 18-Memory, 20-CO2 sensor, 30-Refrigerant circuit, 31-Refrigerant piping, 32-Compressor, 34-Air cooler, 36-Fan, 38-Blower, 40-Heater core, 42-Refrigeration and heating switching door, 43a, 43b-Air inlet, 44-Indoor and outdoor air switching door, 46-Expansion valve for refrigeration, 48-Evaporator, 50-PT sensor, 52-Accumulator, 54-Main body, 56-Heat exchanger, 62-Blowout mechanism, 64-Unit housing.

Claims

1. A vehicle air conditioning system, characterized by comprising: Possessing: An air conditioning device mounted on a vehicle and capable of switching between an inside air circulation mode and an outside air introduction mode; And A controller, The controller, when the vehicle interior temperature is higher than the outside air temperature, causes the air conditioning device to perform refrigeration operation in the outside air introduction mode during refrigeration operation, If the temperature difference between the vehicle interior temperature and the outside air temperature is equal to or less than a predetermined reference value, even if the vehicle interior temperature is higher than the outside air temperature, the air conditioning device is switched to the inside air circulation mode.

2. The vehicle-mounted air conditioning system according to claim 1, wherein The air conditioning device circulates a refrigerant in which CO2 is a main component.

3. The vehicle air conditioning system of claim 2, wherein Further possessing: A CO2 sensor that detects the CO2 concentration in the vehicle interior, In a case where the CO2 concentration detected by the CO2 sensor is equal to or greater than a predetermined reference threshold value, the controller switches to the outside air introduction mode regardless of the temperature.

4. The vehicle-mounted air conditioning system according to claim 1, wherein The controller, in a case where a crew member designates either of the inside air circulation mode and the outside air introduction mode, causes the air conditioning device to perform refrigeration operation in the designated mode regardless of the vehicle interior temperature and the outside air temperature.

5. The vehicle-mounted air conditioning system according to claim 1, wherein The controller, after starting refrigeration operation, does not perform mode switching with the vehicle interior temperature being higher than the outside air temperature as a trigger condition until the refrigeration operation is stopped, after implementing the inside air circulation mode once.

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