Vehicle air conditioning system

Abstract

To provide a vehicle air conditioning system that improves convenience and comfort for occupants, while also achieving energy savings and miniaturization of the device. [Solution] The vehicle air conditioning system 1 comprises an outside air inlet 3, an inside air inlet 4, an inside / outside air switching damper 5, a blower unit 6, a total heat exchanger 7 provided between the outside air inlet 3 and the blower unit 6 which exchanges heat between outside air and return air, which is inside air discharged from the inside of the vehicle to the outside of the vehicle, a first outside air passage 12 through which outside air introduced from the outside air inlet 3 flows into the total heat exchanger 7, a second outside air passage 13 through which outside air introduced from the outside air inlet 3 bypasses the total heat exchanger 7 and flows into the temperature control unit 20, an outside air flow rate adjustment unit 10 which adjusts the ratio of airflow in the first outside air passage 12 and the second outside air passage 13, and a control unit 50. The control unit 50 controls the outside air flow rate adjustment unit 10 to achieve an arbitrary airflow ratio based on the dew point temperature Dp of the air downstream of the total heat exchanger 7.

Description

Technical Field

[0001] The present invention relates to a vehicle air conditioner.

Background Art

[0002] Conventionally, some vehicle air conditioners include a total heat exchanger in an HVAC (Heating, Ventilating, and Air Conditioning) unit. The total heat exchanger is a waste heat recovery means that exchanges sensible heat and latent heat between the inside air exhausted from the vehicle interior to the outside and the outside air introduced from the outside to the inside when ventilating the vehicle interior. The vehicle air conditioner ventilates through the total heat exchanger, and in some cases, mixes, heats, and cools the outside air and the inside air and introduces them into the vehicle interior. Thereby, it is possible to perform air conditioning with a reduced air conditioning load while suppressing temperature changes due to ventilation.

[0003] On the other hand, for example, in the heating operation in winter, the introduced outside air is heated and humidified by the total heat exchanger and then introduced into the vehicle interior. Therefore, the humidity in the vehicle interior tends to rise, which causes window fogging of the front glass.

[0004] Therefore, for the purpose of improving heating performance and preventing window fogging, a vehicle air conditioner is known that provides a passage passing through the total heat exchanger and a passage not passing through the total heat exchanger as passages for the outside air (see, for example, Patent Documents 1 and 2).

[0005] In Patent Document 1, a passage passing through the total heat exchanger and a passage not passing through the total heat exchanger are provided as passages for the outside air, and by inside / outside air switching doors provided in each passage, a state in which outside air is introduced into both passages, a state in which outside air is not introduced into both passages, and a state in which outside air is introduced only into the passage passing through the total heat exchanger can be switched.

[0006] In Patent Document 2, a passage passing through the total heat exchanger and a passage not passing through the total heat exchanger are provided as passages for the outside air, and a configuration is described that enables switching of the introduction of outside air into the passage not passing through the total heat exchanger.

Prior Art Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2010-76506 [Patent Document 2] Patent No. 5640485 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, conventional vehicle air conditioning systems have the problem of not being able to adjust the airflow of outside air that passes through the total heat exchanger and outside air that does not, nor can they adjust the airflow of outside air and inside air according to the conditions inside the vehicle.

[0009] Specifically, the vehicle air conditioning system described in Patent Document 1 offers three options for outside air: introducing both outside air that passes through the total heat exchanger and outside air that does not, introducing neither, or introducing only one type of outside air. It is not possible to adjust (change) the airflow ratio of the two. When outside air passes through the total heat exchanger, this creates resistance and causes airflow loss. Also, if outside air does not pass through the total heat exchanger when window fogging occurs, the load on the temperature control unit (evaporator) increases. In other words, if the airflow ratio of outside air that passes through the total heat exchanger and outside air that does not cannot be adjusted, it is disadvantageous from the standpoint of energy saving efficiency. Furthermore, the configuration does not allow for mixing of the internal air circulating in the vehicle cabin with the outside air, which limits the improvement of passenger comfort and convenience.

[0010] Furthermore, the vehicle air conditioning system described in Patent Document 2 offers only two options for outside air: either introducing outside air that passes through the total heat exchanger or outside air that does not pass through the total heat exchanger, or introducing neither. In this case, it is not possible to adjust (change) the airflow ratio of outside air that passes through the total heat exchanger and outside air that does not, which is disadvantageous from the standpoint of energy saving efficiency. Also, the internal air circulating in the vehicle cabin is configured in a way that prevents mixing with outside air, similar to Patent Document 1, resulting in the same problem.

[0011] Thus, conventional designs had room for improvement in terms of convenience and comfort for occupants, such as preventing window fogging. Furthermore, there were limitations to energy saving through reducing the load on the temperature control system (dehumidification and heating load) and suppressing wind loss.

[0012] Furthermore, as described in Patent Document 2, for example, if an outside air inlet is provided corresponding to both the passage for outside air that passes through the total heat exchanger and the passage for outside air that does not pass through the total heat exchanger, there is a problem that the number of outside air inlets will increase, resulting in a larger device.

[0013] This invention has been made in view of the aforementioned problems and provides a vehicle air conditioning system that improves convenience and comfort for occupants, while also achieving energy savings and miniaturization of the device. [Means for solving the problem]

[0014] The present invention comprises an outside air inlet for introducing outside air, an inside air inlet for introducing inside air, an inside / outside air switching damper for switching the ratio of the introduction of inside air and the outside air, a blower unit provided downstream of the inside / outside air switching damper for supplying air into the vehicle interior, a total heat exchanger provided between the outside air inlet and the blower unit for exchanging heat between the outside air and the return air which is the inside air that is discharged from the vehicle interior to the outside, and a first outside air passage through which the outside air introduced from the outside air inlet flows into the total heat exchanger. The vehicle air conditioning system comprises: a second outside air passage through which the outside air introduced from the outside air inlet bypasses the total heat exchanger; an outside air flow rate adjustment unit that adjusts the airflow ratio between the first outside air passage and the second outside air passage; a temperature control unit that adjusts the temperature of the air supplied to the vehicle interior; and a control unit, wherein the control unit controls the outside air flow rate adjustment unit to achieve an arbitrary airflow ratio based on the dew point temperature of the air downstream of the total heat exchanger. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a vehicle air conditioning system that improves convenience and comfort for occupants, while also achieving energy savings and miniaturization of the device. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram showing an overview of a vehicle air conditioning system according to an embodiment of the present invention. [Figure 2] This is a functional block diagram of a vehicle air conditioning system according to an embodiment of the present invention. [Figure 3] This is a flowchart showing an example of air conditioning control for a vehicle air conditioning system according to an embodiment of the present invention. [Figure 4] This is a flowchart showing an example of air conditioning control for a vehicle air conditioning system according to an embodiment of the present invention. [Figure 5] This is a schematic diagram showing an example of the operation of a vehicle air conditioning system according to an embodiment of the present invention. [Figure 6] This is a schematic diagram showing an example of the operation of a vehicle air conditioning system according to an embodiment of the present invention. [Figure 7] It is a schematic diagram showing an example of the operation of a vehicle air conditioner according to an embodiment of the present invention. [Figure 8] It is a schematic diagram showing an example of the operation of a vehicle air conditioner according to an embodiment of the present invention. [Figure 9] It is a schematic diagram showing an example of the operation of a vehicle air conditioner according to an embodiment of the present invention. [Figure 10] It is a schematic diagram showing an example of the operation of a vehicle air conditioner according to an embodiment of the present invention. [Figure 11] It is a schematic diagram showing another example of a vehicle air conditioner according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIGS. 1 to 11 are an example of the embodiments of the present invention. In the figures, parts with the same reference numerals indicate parts having the same function or the same components, and duplicate explanations in each figure will be omitted as appropriate.

[0018] <Vehicle air conditioner> FIG. 1 is a schematic diagram conceptually showing an example of the configuration of a vehicle air conditioner 1 according to the present embodiment. The vehicle air conditioner 1 is, for example, an HVAC (Heating, Ventilating, and Air Conditioning) unit, and has a temperature control unit 20 and an intake unit 2 that circulates air through the temperature control unit 20.

[0019] The temperature control unit 20 has an air flow path 21, an evaporator 22, a heater core 23, and an air mix damper 25. The air flow path 21 is a passage for air (outside air and / or inside air) introduced from the intake unit 2 and supplied to the vehicle interior by the blower unit 6. The evaporator 22 is provided upstream of the air flow path 21 and constitutes a refrigeration cycle together with a compressor and a condenser (not shown). The evaporator 22 exchanges heat between the refrigerant flowing through its interior and the air passing through the air flow path 21 (the total amount of air introduced from the intake unit 2).

[0020] Downstream of the evaporator 22, the airflow passage 21 can be divided into two passages 21A and 21B, but the two passages 21A and 21B merge downstream and connect to the air outlet 24 in the passenger compartment. Air mix dampers 25 are provided on the upstream side of the two passages 21A and 21B, and a heater core 23 is positioned in one of the passages 21B downstream of the air mix damper 25. The air mix damper 25 is rotatable between a position that opens passage 21A and closes passage 21B, and a position that closes passage 21A and opens passage 21B. When the air mix damper 25 is in the position that opens passage 21A and closes passage 21B, all the air that has passed through the evaporator 22 passes through passage 21A. When the air mix damper 25 is in the position that closes passage 21A and opens passage 21B, all the air that has passed through the evaporator 22 bypasses passage 21A. When the air mix damper 25 is in a position that opens both the flow path 21A and the flow path 21B, some of the air that has passed through the evaporator 22 passes through the flow path 21A, and the remainder bypasses the flow path 21A. Downstream, the air that has passed through the flow path 21A and the air that has bypassed the flow path 21A are mixed and supplied to the passenger compartment from the outlet 24.

[0021] The intake unit 2 is located upstream of the temperature control unit 20 and includes an outside air inlet 3 for introducing outside air from outside the vehicle into the vehicle interior, an inside air inlet 4 for introducing inside air from inside the vehicle interior, an inside / outside air switching damper 5 for switching the ratio of inside and outside air introduction, an outside air flow rate adjustment unit 10 located downstream of the outside air inlet 3 and the inside air inlet 4, two inside air passages 11, 14 and two outside air passages 12, 13, a filter 8, a total heat exchanger 7 located between the outside air inlet 3 and the blower unit 6, and a blower unit 6 located downstream of the inside / outside air switching damper 5 for supplying air to the temperature control unit 20 and the vehicle interior, and a motor 6M which is its driving source.

[0022] One outside air inlet 3 and one inside air inlet 4 are provided in the case of the intake unit 2. The inside / outside air switching damper 5 is located downstream of the outside air inlet 3 and the inside air inlet 4 and is pivotable around the pivot axis 5A. By rotating the inside / outside air switching damper 5 at its maximum opening in one direction (clockwise in Figure 1) around the pivot axis 5A, the inside air inlet 4 is closed and the outside air inlet 3 is opened, allowing only outside air to be introduced. Conversely, by rotating at its maximum opening in the other direction (counterclockwise in Figure 1) around the pivot axis 5A, the inside air inlet 4 is opened and the outside air inlet 3 is closed, allowing only inside air to be introduced. Furthermore, it can rotate in any direction at an opening smaller than the maximum opening (greater than 0 degrees) around the pivot axis 5A, thereby allowing both outside and inside air to be introduced.

[0023] Air (outside air and / or inside air) introduced from the outside air inlet 3 and / or inside air inlet 4 passes through the filter 8, and some of it is supplied to the blower unit 6 via the total heat exchanger 7 if necessary. The blower unit 6 sends this air to the air passage 21 of the temperature control unit 20.

[0024] The total heat exchanger 7 is a means of recovering exhaust heat when ventilating the vehicle interior. During ventilation, outside air is taken in, and a portion of the inside air is discharged outside the vehicle interior. The portion of inside air discharged outside the vehicle interior at this time is distinguished from the inside air circulating inside the vehicle and will be referred to as "return air" below. The total heat exchanger 7 passes the return air exhausted from the vehicle interior and a portion of the outside air introduced from outside the vehicle interior through it, exchanging sensible heat and latent heat to perform ventilation. The total heat exchanger 7 is, for example, a rotary total heat exchanger, and since its configuration is known, a detailed explanation will be omitted, but for example, its external appearance is cylindrical, and an air passage (not shown) for outside air and return air is provided in the direction of the axis 7A. A heat exchange material carrying a desiccant such as silica gel or zeolite is placed in the air passage, and by rotating it around the axis 7A by the motor 7M, which is the drive source, the outside air and return air passing through the air passage exchange heat. Also, on the air downstream side of the total heat exchanger 7, an exhaust passage 15 for discharging return air and a one-way valve 9 for opening and closing it are provided.

[0025] The return air exhausted from the vehicle interior and a portion of the outside air introduced from outside the vehicle interior are passed through the total heat exchanger 7, exchanging sensible heat and latent heat. As a result, for example, in winter, the low-temperature outside air is heated and humidified through heat exchange with the high-temperature return air before being introduced into the vehicle interior, and in summer, the high-temperature outside air is cooled and dehumidified through heat exchange with the low-temperature return air before being introduced into the vehicle interior. This suppresses temperature changes inside the vehicle interior due to ventilation and reduces the air conditioning load on the temperature control unit 20.

[0026] On the other hand, if, for example, the entire amount of outside air introduced from the outside air intake 3 in winter is heated and humidified by the total heat exchanger 7 and supplied to the vehicle interior, depending on the temperature and humidity conditions outside and inside the vehicle, the humidity inside the vehicle interior may easily rise, which could cause the windshield to fog up.

[0027] Therefore, in this embodiment, an outside air flow rate adjustment unit 10, a first internal air passage 11, a first outside air passage 12, a second outside air passage 13, and a second internal air passage 14 are provided between the outside air inlet 3 and the internal air inlet 4 and the temperature control unit 20 (air blower 6).

[0028] The first internal air passage 11 is a passage through which return air discharged outside the vehicle compartment passes. Its upstream end communicates with the internal air inlet 4, and its downstream end communicates with the total heat exchanger 7. The entire amount of return air is exhausted outside the vehicle compartment via the first internal air passage 11, the total heat exchanger 7, and the exhaust passage 15. The amount of return air is approximately the same as the amount of outside air introduced.

[0029] The first outside air passage 12 is a passage through which at least a portion of the outside air introduced from the outside air inlet 3 passes. Its upstream end communicates with the outside air inlet 3, and its downstream end communicates with the total heat exchanger 7. In other words, the outside air passing through the first outside air passage 12 undergoes heat exchange in the total heat exchanger 7 before being introduced into the temperature control unit 20.

[0030] The second outside air passage 13 is a passage through which at least a portion of the outside air introduced from the outside air inlet 3 passes. Its upstream end communicates with the outside air inlet 3, and its downstream end bypasses the total heat exchanger 7 and communicates with the upstream side of the air blower 6 (temperature control unit 20). In other words, the outside air passing through the second outside air passage 13 is introduced into the temperature control unit 20 without undergoing heat exchange in the total heat exchanger 7.

[0031] The second internal air passage 14 is a passage through which the internal air circulating in the vehicle cabin passes. Its upstream end communicates with the internal air inlet 4, and its downstream end bypasses the total heat exchanger 7 and communicates with the upstream side of the air blower 6 (temperature control unit 20). In other words, the internal air passing through the second internal air passage 14 is introduced into the temperature control unit 20 without undergoing heat exchange in the total heat exchanger 7.

[0032] In other words, in this embodiment, the intake unit 2 has one outside air inlet 3 and one inside air inlet 4. The outside air introduced from the outside air inlet 3 has a first outside air passage 12 and a second outside air passage 13, and the inside air introduced from the inside air inlet 4 has a first inside air passage 11 and a second inside air passage 14.

[0033] Furthermore, an outside air flow rate adjustment unit 10 is provided downstream of the outside air inlet 3 and upstream of the total heat exchanger 7, more specifically upstream of the first outside air passage 12 and the second outside air passage 13. The outside air flow rate adjustment unit 10 is, for example, a damper that is configured to swing freely around a pivot shaft 10A and can adjust the opening degree of the upstream side of the first outside air passage 12 and the second outside air passage 13.

[0034] As an example, the first outside air passage 12 and the second outside air passage 13 are provided adjacent to each other. The pivot shaft 10A of the outside air flow rate adjustment unit 10 is provided as a partition between them. The outside air flow rate adjustment unit 10 rotates at its maximum opening in one direction (clockwise in Figure 1) around the pivot shaft 10A, thereby opening the first outside air passage 12 and closing the second outside air passage. As a result, the entire amount of outside air introduced from the outside air inlet 3 passes through the total heat exchanger 7 and is supplied to the temperature control unit 20 (blower unit 6). Conversely, by rotating at its maximum opening in the other direction (counterclockwise in Figure 1) around the pivot shaft 10A, the first outside air passage 12 is closed and the second outside air passage 13 is opened. As a result, the entire amount of outside air introduced from the outside air inlet 3 bypasses the total heat exchanger 7 and is supplied to the temperature control unit 20 (blower unit 6). Furthermore, the pivot axis 10A can be rotated in any direction at any opening (greater than 0 degrees) smaller than the maximum opening, thereby enabling the supply of outside air passing through the total heat exchanger 7 and outside air bypassing the total heat exchanger 7 to the temperature control unit 20 (air blower unit 6) at any desired airflow ratio.

[0035] The outside air flow rate adjustment unit 10 can be arbitrarily adjusted based on the state of the air supplied to the vehicle interior, specifically the dew point temperature of the air supplied to the vehicle interior, thereby arbitrarily adjusting the flow rate of outside air flowing through the first outside air passage 12 and the second outside air passage 13. In other words, the ratio of the airflow rates of the two can be adjusted (changed). More specifically, a temperature and humidity sensor 26 is provided upstream of the temperature control unit 20, specifically near the air blower unit 6, preferably immediately downstream of the air blower unit 6. In addition, a glass surface temperature sensor 27 is provided inside the vehicle interior to measure its temperature, specifically the surface temperature of the windshield. The control unit of the vehicle air conditioning system 1 measures the temperature and humidity of the outside air and / or inside air supplied to the vehicle interior from the air blower unit 6 using the temperature and humidity sensor 26 and calculates the dew point temperature Dp. Furthermore, the temperature Tg of the windshield surface obtained by the glass surface temperature sensor 27 is compared with the dew point temperature Dp. If the dew point temperature Dp exceeds the temperature Tg of the windshield surface, condensation (window fogging) will occur on the car window, so the proportion of outside air introduced to bypass the total heat exchanger 7 is increased. As a result, the amount of air that has not been humidified (is dry) by the total heat exchanger 7 increases, and the dew point temperature Dp is lowered. In other words, for example, during heating, window fogging can be eliminated without dehumidification by the temperature control unit 20 (evaporator 22), or by reducing dehumidification by the temperature control unit 20 (evaporator 22).

[0036] Furthermore, instead of passing all of the outside air introduced from the outside air inlet 3 through the total heat exchanger 7, some of the outside air can be diverted to bypass the total heat exchanger 7, thereby suppressing wind loss caused by passing through the total heat exchanger 7. In other words, energy saving efficiency can be improved by reducing the load on the temperature control unit 20 (for example, the load of heating and dehumidifying operation) and suppressing wind loss.

[0037] On the other hand, if the dew point temperature Dp of the outside air and / or inside air supplied to the vehicle interior is lower than the temperature Tg of the windshield surface, the proportion of outside air introduced through the total heat exchanger 7 is increased. In this case, the amount of air heated by the total heat exchanger 7 increases, and as a result, the load on the temperature control unit 20 (for example, the load of reheating by the heater core 23 during heating operation) is reduced.

[0038] Furthermore, if the dew point temperature Dp significantly exceeds the windshield surface temperature Tg, and it becomes difficult to lower the dew point temperature Dp simply by increasing the proportion of outside air introduced to bypass the total heat exchanger 7, the proportion of outside air introduced to bypass the total heat exchanger 7 is increased, and dehumidification is also performed by the temperature control unit 20. That is, the refrigerant is circulated through the evaporator 22 to dehumidify the air passing through the air passage 21. This reliably suppresses window fogging.

[0039] Furthermore, the outside air flow rate adjustment unit 10 can adjust the flow rate of outside air flowing to the total heat exchanger 7 and the flow rate of outside air bypassing the total heat exchanger 7 by any ratio based on the dew point temperature of the outside air and / or inside air. Therefore, it is possible to broaden the range in which both the suppression of condensation and window fogging inside the vehicle interior and the energy-saving effect through exhaust heat recovery can be achieved. In other words, it is possible to broaden the range in which improvements in occupant convenience and comfort can be achieved simultaneously with energy-saving effects.

[0040] Furthermore, the opening of the outside air flow rate adjustment unit 10 is also adjusted according to the amount of air supplied to the vehicle interior. For example, if a high airflow rate is required for the air blown into the vehicle interior from the outlet 24, the airflow rate of the blower unit 6 is increased. If this exceeds the capacity, the opening of the outside air inlet 3 of the inside / outside air switching damper 5 is increased, and the opening of the second outside air passage 13 side of the outside air flow rate adjustment unit 10 is also increased. This increases the amount of outside air introduced and further increases the amount of outside air that bypasses the total heat exchanger 7. When outside air passes through the total heat exchanger 7, this creates resistance and causes wind loss, but by increasing the opening of the second outside air passage 13 side of the outside air flow rate adjustment unit 10, wind loss can be suppressed and the amount of air blown into the vehicle interior can be increased.

[0041] Furthermore, in this embodiment, by adjusting the opening of the internal / external air switching damper 5 to an opening smaller than the maximum opening and communicating with both the external air inlet 3 and the internal air inlet 4, a mixture of external and internal air can be supplied to the vehicle interior. By adjusting the opening of the external air flow rate adjustment unit 10, both external air that has passed through the total heat exchanger 7 and external air that has bypassed the total heat exchanger 7 can be mixed with internal air, and air that is suitable for the conditions inside the vehicle interior or that can further improve energy efficiency can be supplied to the temperature control unit 20.

[0042] Furthermore, since the air is divided into a first outside air passage 11 and a second outside air passage 12 downstream of the single outside air inlet 3, there is no need to provide an outside air inlet for the intake unit 2, thus suppressing the need to increase the size of the intake unit 2 and, consequently, the vehicle air conditioning system 1.

[0043] Furthermore, as schematically shown in Figure 1, arranging the first outside air passage 11 and the first inside air passage 12, which communicates with the exhaust passage 15, adjacent to each other can suppress the need to increase the size of the vehicle air conditioning system. In addition, if the return air discharged from the exhaust passage 15 is at a high temperature, the heat from that air may warm the case of the vehicle air conditioning system 1 (HVAC unit, etc.). However, by having the first outside air passage 11 and the first inside air passage 12 adjacent to each other, the temperature of the return air passing through the first inside air passage 12 can be recovered by the outside air passing through the first outside air passage 11, thereby suppressing the discharge of high-temperature return air.

[0044] Note that Figure 1 is a schematic diagram, and the arrangement of the first internal air passage 11, the first external air passage 12, the second external air passage 13, and the second internal air passage 14 is not limited to the example in Figure 1. As an example, the arrangement shown in Figure 1 is configured to facilitate exhaust.

[0045] Furthermore, for example, if a larger temperature difference is desirable from the viewpoint of heat exchange in the temperature control unit 20, it is desirable to arrange flow paths with similar temperature ranges in close proximity. For example, the first internal air flow path 11 and the second internal air flow path 14 may be arranged adjacent to each other.

[0046] For example, in a two-layer HVAC system that circulates air between an upper and lower layer, if the second outside air passage 13 and the second inside air passage 14 are adjacent to each other when heat exchange occurs between the evaporator 22 and the heater core 23 in the temperature control unit 20, heat transfer will occur upstream of the temperature control unit 20. To suppress such unwanted heat transfer, it is preferable to place passages with similar temperature ranges adjacent to each other, i.e., the first inside air passage 11 and the second inside air passage 14, so that, for example, from left to right in the diagram, the arrangement is second outside air passage 13, first outside air passage 12, first inside air passage 11, and second inside air passage 14. This suppresses unwanted heat transfer in each of the first inside air passage 11, first outside air passage 12, second outside air passage 13, and second inside air passage 14.

[0047] Furthermore, the upstream flow path of the total heat exchanger 7 in the first internal air flow path 11 and the second external air flow path 13 may be arranged adjacent to each other. This allows heat from the return air to be transferred to the outside air that bypasses the total heat exchanger 7, thus enabling efficient recovery of the heat from the return air.

[0048] <Air Conditioning Control> Referring to Figures 2 to 4, an example of air conditioning control in the vehicle air conditioning system 1 of this embodiment will be described. Figure 2 is a functional block diagram showing an example of when the control unit 50 of the vehicle air conditioning system 1 performs air conditioning control. The control unit 50 can perform various air conditioning controls, but Figure 2 specifically shows the functional block for performing air conditioning control (outside air flow rate adjustment control) in this embodiment. Figure 3 is a flowchart showing an example of the transition of multiple air supply modes in the intake unit 2 of the vehicle air conditioning system 1, and Figure 4 is a flowchart showing an example of the flow of outside air flow rate adjustment control by the control unit 50.

[0049] The control unit 50 can perform, for example, heating operation, cooling operation, ventilation operation, and heating dehumidification operation as air conditioning control. The intake unit 2 has three modes for supplying air to the temperature control unit 20 and the vehicle interior, such as internal air circulation mode, external air introduction mode, and internal / external air mixing mode, and the external air introduction mode and internal / external air mixing mode each have a low airflow mode and a high airflow mode, which can be switched between.

[0050] Referring to Figure 2, the control unit 50 includes an air conditioning control unit 51, an indoor / outdoor airflow control unit 52, an outdoor airflow rate adjustment control unit 53, etc. A temperature and humidity sensor 26 and a glass surface temperature sensor 27, etc. are connected to the input side of the control unit 50, and their outputs are input to the control unit 50. In addition, an indoor / outdoor air switching damper 5, a blower unit 6, an outdoor airflow rate adjustment unit 10, a temperature control unit 20, etc. are connected to the output side of the control unit 50, and the control unit 50 controls the operation of these components.

[0051] Furthermore, the outside air flow rate control in this embodiment primarily performs dehumidification in situations where dehumidification of the vehicle interior is necessary by adjusting the airflow ratio of the outside air introduced by the intake unit 2 between the outside air that passes through the total heat exchanger 7 and the outside air that bypasses it. Specifically, for example, when window fogging occurs during ventilation operation in the transitional seasons other than winter and summer, or when window fogging occurs during heating operation (in which case dehumidification is generally not necessary), dehumidification is performed by adjusting the airflow ratio of the outside air that passes through the total heat exchanger 7 and the outside air that bypasses it.

[0052] If the humidity inside the vehicle remains high even after dehumidification by adjusting the outside airflow, the system switches to a dehumidification operation (for example, heating dehumidification operation) that circulates refrigerant through the temperature control unit 20. This reduces the load on the temperature control unit 20 during dehumidification.

[0053] Referring to Figure 3, an example of the transition between multiple air supply modes in the intake unit 2 will be explained.

[0054] In step S01, the control unit 50 determines whether the conditions for the internal air circulation mode are met, that is, whether the internal air circulation mode has been selected by user operation from the operating unit (not shown) of the vehicle air conditioning system 1. If the conditions are met, the unit proceeds to step S03; otherwise, the unit proceeds to step S05.

[0055] In step S03, the control unit 50 (inside / outside airflow control unit 52) ​​operates the intake unit 2 in inside air circulation mode. Specifically, it adjusts the opening of the inside / outside air switching damper 5 so that the inside air inlet 4 is opened 100% and the outside air inlet 3 is closed. The control unit 50 (air conditioning control unit 51) also operates the blower unit 6 to circulate the inside air into the vehicle cabin. The process then returns to step S01.

[0056] In step S05, the control unit 50 determines whether the conditions for the outside air intake mode are met, that is, whether the outside air intake mode has been selected by user operation from the operating unit (not shown) of the vehicle air conditioning system 1. If the conditions are met, the unit proceeds to step S07; otherwise, the unit proceeds to step S13.

[0057] In step S07, the control unit 50 obtains the airflow rate selected by the user (the airflow rate requested by the vehicle air conditioning system 1, the requested airflow rate) and determines whether the requested airflow rate is equal to or greater than the threshold for the outside air intake airflow rate. If the requested airflow rate is below the threshold, the process proceeds to step S09; if the requested airflow rate is equal to or greater than the threshold, the process proceeds to step S11.

[0058] In step S09, the control unit 50 (inside / outside airflow control unit 52) ​​operates the intake unit 2 in outside air intake mode. Specifically, it adjusts the opening of the inside / outside air switching damper 5 so that the outside air inlet 3 is opened 100% and the inside air inlet 4 is closed, introducing outside air into the vehicle cabin. The control unit 50 (air conditioning control unit 51) also operates the blower unit 6 at low airflow to introduce outside air into the vehicle cabin. The process then returns to step S01.

[0059] In step S11, the control unit 50 (inside / outside airflow control unit 52) ​​operates the intake unit 2 in outside air intake mode. Specifically, it adjusts the opening of the inside / outside air switching damper 5 so that the outside air inlet 3 is opened 100% and the inside air inlet 4 is closed, introducing outside air into the vehicle cabin. The control unit 50 (air conditioning control unit 51) also operates the blower unit 6 at high airflow to introduce outside air into the vehicle cabin. The process then returns to step S01.

[0060] When the operating mode of the vehicle air conditioning system 1 is set to automatic control, it operates in high airflow mode when there is a large difference between the temperature inside the vehicle and the required temperature. However, as time passes and the temperature stabilizes (the difference between the temperature inside the vehicle and the required temperature decreases), it switches to low airflow mode.

[0061] In step S13, the control unit 50 determines whether the requested airflow is equal to or greater than a preset threshold for the mixed airflow of the internal and external air. If the requested airflow is below the threshold, the process proceeds to step S15; if the requested airflow is equal to or greater than the threshold, the process proceeds to step S17. The threshold for the mixed airflow of the internal and external air is set, for example, based on the required ventilation rate determined by the carbon dioxide concentration inside the vehicle cabin.

[0062] In step S15, the control unit 50 (inside / outside air volume control unit 52) ​​operates the intake unit 2 in inside / outside air mixed mode. Specifically, it adjusts the opening of the inside / outside air switching damper 5 so that both the outside air inlet 3 and the inside air inlet 4 are open, introducing outside air and inside air into the vehicle cabin. The control unit 50 (air conditioning control unit 51) also operates the blower unit 6 at a low air volume to introduce outside air into the vehicle cabin. At this time, for example, the opening of the outside air inlet 3 is adjusted based on the required ventilation volume based on the carbon dioxide concentration in the vehicle cabin and the air volume of the blower unit 6. The process then returns to step S01.

[0063] In step S17, the control unit 50 (inside / outside air volume control unit 52) ​​operates the intake unit 2 in inside / outside air mixed mode. Specifically, it adjusts the opening of the inside / outside air switching damper 5 so that both the outside air inlet 3 and the inside air inlet 4 are open, introducing outside air and inside air into the vehicle cabin. The control unit 50 (air conditioning control unit 51) also operates the blower unit 6 at high air volume to introduce outside air into the vehicle cabin. At this time, for example, the opening of the outside air inlet 3 is adjusted based on the required ventilation volume based on the carbon dioxide concentration in the vehicle cabin and the air volume of the blower unit 6. The process then returns to step S01.

[0064] Figure 4 is a flowchart showing an example of the flow of outside air flow rate adjustment control based on the dew point temperature Dp by the control unit 50 (outside air flow rate adjustment control unit 53). The outside air flow rate adjustment control shown in Figure 4 is a control that adjusts the proportion of outside air introduced from the outside air inlet 3 that passes through the total heat exchanger 7, and is executed when the intake unit 2 is in outside air introduction mode and inside / outside air mixing mode (from step S05 onwards in the flow in Figure 3). In the inside air circulation mode, the inside air circulating in the vehicle interior (inside air passing through the second inside air passage 14) does not pass through the total heat exchanger 7 and does not exchange heat with outside air. However, in ventilation operation, the return air (part of the inside air) that passes through the first inside air passage 11 and is discharged outside the vehicle interior passes through the total heat exchanger 7 and exchanges heat with outside air.

[0065] First, in step S21, the control unit 50 (outside air flow rate adjustment control unit 53) acquires the detected value (windshield surface temperature Tg) from the glass surface temperature sensor 27 and proceeds to step S23. In step S23, the outside air flow rate adjustment control unit 53 acquires the measured value from the temperature and humidity sensor 26 of the vehicle air conditioning system 1. The measured value from the temperature and humidity sensor 26 is, for example, the temperature and humidity of the air (outside air / and / or inside air, hereinafter referred to as "in-cabin supplied air") immediately after passing through the air blower 6. Then the process proceeds to step S25. In step S25, the outside air flow rate adjustment control unit 53 calculates the dew point temperature Dp of the in-cabin supplied air based on the temperature and humidity of the in-cabin supplied air.

[0066] In step S27, the outside air flow rate adjustment control unit 53 compares the windshield surface temperature Tg with the dew point temperature Dp of the air supplied to the cabin. If the windshield surface temperature Tg exceeds the sum of the dew point temperature Dp of the air supplied to the cabin and the correction constant α, the process proceeds to step S29; otherwise, it proceeds to step S31. Here, the correction constant α is a constant (coefficient) used to correct the dew point temperature Dp. Due to dirt on the windshield surface, etc., window fogging (condensation) may occur even if the temperature is higher than the dew point temperature Dp of the air supplied to the cabin, so the correction constant α is added to the dew point temperature Dp and compared with the windshield surface temperature Tg.

[0067] In step S29, since there is sufficient temperature margin before window fogging occurs, the proportion of outside air that passes through the first outside air passage 12 (i.e., through the total heat exchanger 7) from the outside air intake 3 is increased from the current value. The outside air flow rate adjustment control unit 53 adjusts the opening of the first outside air passage 12 of the outside air flow rate adjustment unit 10 to be greater than the current opening. The current opening of the first outside air passage 12 is acquired, for example, at the start of step S29. As a result, for example, during heating operation, the amount of outside air heated by the total heat exchanger 7 increases, reducing the load on the temperature control unit 20 (for example, the load of reheating the heater core) and improving energy efficiency. The process then returns to step S21.

[0068] In step S31, because window fogging may occur, the proportion of outside air that passes through the second outside air passage 13 (i.e., bypasses the total heat exchanger 7) from the outside air intake 3 is increased from the current value. The outside air flow rate adjustment control unit 53 adjusts the opening of the second outside air passage 13 of the outside air flow rate adjustment unit 10 to be greater than the current value. The current opening of the second outside air passage 13 is acquired, for example, at the start of step S31. As a result, for example during heating, the proportion of outside air that has not been humidified by the total heat exchanger 7 increases, thereby lowering the dew point temperature Dp of the air supplied to the vehicle cabin.

[0069] In step S33, it is determined whether the difference between the dew point temperature Dp of the in-cabin air supply and the windshield surface temperature Tg is greater than a predetermined threshold (calculation constant) β (i.e., whether the dew point temperature Dp significantly exceeds the windshield surface temperature Tg). Specifically, it is determined whether the value obtained by subtracting the windshield surface temperature Tg from the sum of the dew point temperature Dp and the correction constant α exceeds the calculation constant β. If it does, the process proceeds to step S35; otherwise, the process proceeds to step S37. Note that in the case of air conditioning operation, dehumidification is also performed (simultaneously) by the temperature control unit 20, so steps S33 to S37 are performed in cases other than air conditioning operation.

[0070] In step S35, even though the airflow rate of the second outside air passage 13 that bypasses the total heat exchanger 7 is increased in step S31, the dew point temperature Dp remains high. Therefore, the control unit 50 (air conditioning control unit 51) performs dehumidification operation (for example, heating dehumidification operation) by the temperature control unit 20. The process then returns to step S21.

[0071] In step S37, if dehumidification operation (for example, heating dehumidification operation) was performed by the temperature control unit 20 in step S35, the dehumidification operation is stopped (if no dehumidification operation is performed, it is left as is) and the process returns to step S21.

[0072] In this embodiment, if the dew point temperature Dp of the in-cabin air (plus a correction constant α) exceeds the windshield surface temperature Tg, the control unit 50 first increases the airflow ratio of the outside air that bypasses the total heat exchanger 7 (second outside air flow path 13) from the outside air inlet 3 introduced into the intake unit 2. Then, if the dew point temperature Dp is significantly higher than the windshield surface temperature Tg, the control unit 50 performs a dehumidification operation by flowing refrigerant through the temperature control unit 20.

[0073] In this way, the proportion of outside air flowing through the total heat exchanger 7 can be arbitrarily controlled based on the vehicle conditions (windshield surface temperature Tg and dew point temperature Dp of the air supplied to the cabin). This prevents fogging of the windshield while also allowing exhaust heat recovery in the total heat exchanger 7 according to the vehicle conditions, thus achieving both improved comfort and convenience for occupants and energy savings.

[0074] Furthermore, if the dew point temperature Dp of the air supplied inside the vehicle is lower than the windshield surface temperature Tg, the control unit 50 controls the outside air flow rate adjustment unit 10 so that the proportion of outside air flowing to the total heat exchanger 7 from the outside air intake 3 increases from the current value. This increases the amount of outside air that undergoes heat exchange in the total heat exchanger 7, thereby improving energy efficiency.

[0075] Furthermore, if the windshield surface temperature Tg is higher than the dew point temperature Dp of the air supplied to the vehicle interior and the temperature difference is less than or equal to a predetermined value, or if the windshield surface temperature Tg is lower than the dew point temperature Dp, the control unit 50 controls the outside air flow rate adjustment unit 10 to increase the proportion of outside air that bypasses the total heat exchanger 7 from the outside air inlet 3. This increases the amount of outside air that bypasses the total heat exchanger 7, and since the dew point temperature Dp can be lowered without relying on dehumidification operation by the temperature control unit 20, window fogging can be prevented, thus improving energy efficiency.

[0076] Furthermore, the control unit 50 controls the temperature control unit 20 (by flowing refrigerant) to perform dehumidification when the windshield surface temperature Tg is lower than the dew point temperature Dp of the air supplied to the cabin and the temperature difference exceeds a predetermined value. In this way, window fogging can be reliably prevented. In addition, since dehumidification is performed by the intake unit 2 (upstream of the temperature control unit 20) and dehumidification by the temperature control unit 20 is performed only when the dew point temperature Dp is still high, energy saving can be improved compared to a configuration in which dehumidification is not performed by the intake unit 2, or a configuration in which dehumidification is performed by the temperature control unit and then supplemented by introducing outside air from the intake unit 2.

[0077] Furthermore, the control unit 50 can supply a mixture of internal air (internal air circulating in the cabin) and external air to the cabin by controlling the internal / external air switching damper 5, excluding the return air. In particular, in this embodiment, based on the windshield surface temperature Tg and the dew point temperature Dp of the air supplied to the cabin, the airflow ratio of the external air passing through the total heat exchanger 7 and the external air bypassing the total heat exchanger 7 can be arbitrarily adjusted, and the mixture of external and internal air can be supplied to the cabin. In other words, it is possible to supply external air passing through the total heat exchanger 7, a mixture of external and internal air bypassing the total heat exchanger 7, or a mixture of external and internal air bypassing the total heat exchanger 7 to the cabin, thereby improving the convenience and comfort of the occupants while also achieving energy savings.

[0078] In particular, in the internal / external air mixing mode (steps S13 to 17 shown in Figure 3), the outside air passing through the first external air passage 12 and the second external air passage 13 is mixed with the internal air passing through the second internal air passage 14 and supplied to the vehicle interior. In this embodiment, as an example, the airflow rate of the outside air passing through the first external air passage 12 and the second external air passage 13 is set based on the required ventilation rate (external air rate) based on the carbon dioxide concentration in the vehicle interior. In order to maintain this required return air rate, the external air flow rate adjustment control shown in Figure 4 does not adjust the internal / external air switching damper 5, but only adjusts the opening degree of the external air flow rate adjustment unit 10.

[0079] The above describes the control of outside air flow rate based on the windshield surface temperature Tg and the dew point temperature Dp. The control unit 50 (outside air flow rate adjustment unit 53) can adjust the outside air flow rate adjustment unit 10 according to the amount of air required to be supplied to the vehicle interior. Specifically, when the amount of air required to be supplied to the vehicle interior exceeds a predetermined value, the control unit 50 (outside air flow rate adjustment unit 53) adjusts the opening of the outside air flow rate adjustment unit 10 so that the proportion of air flowing through the second outside air passage 13 increases.

[0080] For example, when a high airflow is required for the air blown into the vehicle interior from the outlet 24, specifically in the outside air intake (high airflow) mode and the internal air mixing (high airflow mode) shown in Figure 3, the control unit 50 (air conditioning control unit 51) increases the airflow rate of the blower unit 6. If the required airflow exceeds the capacity of the blower unit 6, the control unit 50 increases the opening of the outside air intake port 3 of the internal / external air switching damper 5 and also increases the opening of the second outside air passage 13 side of the outside air flow rate adjustment unit 10 (for example, increasing the airflow ratio of the second outside air passage 13 compared to the first outside air passage 12). This increases the amount of outside air introduced and further increases the amount of outside air that bypasses the total heat exchanger 7. By increasing the opening of the second outside air passage 13 side of the outside air flow rate adjustment unit 10, wind loss can be suppressed and the amount of air blown into the vehicle interior can be increased.

[0081] Next, an example of the operation of the vehicle air conditioning system 1 will be explained with reference to Figures 5 to 9.

[0082] <Winter outside air intake (low airflow) mode> Figure 5 shows an example of operation in winter (when heating operation is performed) in outside air intake (low airflow) mode. In winter, the outside air introduced from the outside air inlet 3 is cold, and the inside air circulating in the vehicle interior is hot. The cold outside air passing through the total heat exchanger 7 is humidified and heated through heat exchange with the hot return air. In the temperature control unit 20, the air passing through the air passage 21 (air supplied to the vehicle interior) passes through the evaporator 22, but no refrigerant flows through the evaporator 22. Instead, it passes through the heater core 23 and is blown into the vehicle interior from the flow path 21B.

[0083] Referring to Figure 5, in this case, the internal / external air switching damper 5 is adjusted to close the internal air inlet 4 and open the external air inlet 3 to its maximum opening. The external air flow rate adjustment unit 10 is adjusted, for example, to close the second external air passage 13 and open the first external air passage 12 to its maximum opening.

[0084] The low-temperature outside air introduced from the outside air inlet 3 passes entirely through the first outside air passage 12 and the first inside air passage 11, and exchanges heat with the high-temperature return air that is discharged outside the vehicle in the total heat exchanger 7. The return air passes through the exhaust passage 15 and is discharged outside the vehicle compartment from the one-way valve 9.

[0085] The outside air that has passed through the total heat exchanger 7 is drawn into the blower unit 6 in a heated state and supplied to the air passage 21 of the temperature control unit 20. In heating operation, the temperature control unit 20 does not flow refrigerant through the evaporator 22, but instead allows outside air to pass through. Downstream of the evaporator 22, the air mix damper 25 is positioned to close the flow path 21A, and the outside air that has passed through the evaporator 22 passes through the heater core 23, is reheated as needed, and blown into the passenger compartment.

[0086] In the total heat exchanger 7, the outside air is heated by the heat exchange between the outside air and the return air, thus reducing the heating load on the heater core 23. Although the total heat exchanger 7 acts as resistance, in low airflow mode, even if the entire volume of outside air passes through the total heat exchanger 7, the impact on airflow loss is minimal.

[0087] The control unit 50 controls the outside air flow rate adjustment unit 10 based on the windshield surface temperature Tg and the dew point temperature Dp of the air supplied to the vehicle interior. As shown in Figure 5, when the outside air flow rate adjustment unit 10 has the first outside air passage 12 open to its maximum degree, if, for example, the dew point temperature Dp of the air supplied to the vehicle interior exceeds the windshield surface temperature Tg, the control unit 50 adjusts the opening of the outside air flow rate adjustment unit 10 so that the second outside air passage 13 side opens, and increases the airflow rate of the second outside air passage 13 (step S31 shown in Figure 4) to prevent window fogging.

[0088] <Winter outside air intake (high airflow) mode> Figure 6 shows an example of operation in the winter (when heating operation is performed) outside air intake (high airflow) mode. In this case, the inside / outside air switching damper 5 is adjusted to close the inside air inlet 4 and open the outside air inlet 3 to its maximum opening. In this example, the outside air flow rate adjustment unit 10 is also adjusted so that the opening of the first outside air passage 12 and the second outside air passage 13 is at an arbitrary airflow ratio.

[0089] The low-temperature outside air introduced through the outside air inlet 3 partially passes through the first outside air passage 12 and the first inside air passage 11, and exchanges heat with the high-temperature return air that is discharged outside the vehicle in the total heat exchanger 7. The return air passes through the exhaust passage 15 and is discharged outside the vehicle compartment from the one-way valve 9.

[0090] Furthermore, some of the low-temperature outside air introduced from the outside air inlet 3 (outside the outside air that passes through the first outside air passage 12) passes through the second outside air passage 13 and bypasses the total heat exchanger 7.

[0091] The outside air that has passed through the total heat exchanger 7 is drawn into the blower unit 6 in a heated state. The blower unit 6 also draws in outside air that has bypassed the total heat exchanger 7, and both are supplied to the airflow passage 21 of the temperature control unit 20. In heating operation, the temperature control unit 20 does not flow refrigerant through the evaporator 22, but instead allows outside air to pass through. Downstream of the evaporator 22, the air mix damper 25 is positioned to close the flow path 21A, and the outside air that has passed through the evaporator 22 passes through the heater core 23, is reheated, and then blown into the passenger compartment.

[0092] If there is a requirement for high airflow and even with the maximum capacity of the blower unit 6, the amount of outside air that has passed through the total heat exchanger 7 is insufficient to blow into the vehicle cabin, the control unit 50 adjusts the opening of the outside air flow rate adjustment unit 10 so that a portion of the outside air also passes through the second outside air passage 13. Since the outside air passing through the second outside air passage 13 does not suffer any airflow loss due to passing through the total heat exchanger 7, the requirement for high airflow can be met.

[0093] Furthermore, in the total heat exchanger 7, a portion of the outside air is heated by the heat exchange between the outside air and the return air. This reduces the load on the temperature control unit 20.

[0094] The control unit 50 controls the outside air flow rate adjustment unit 10 based on the windshield surface temperature Tg and the dew point temperature Dp of the air supplied to the vehicle interior. As shown in Figure 6, if the outside air flow rate adjustment unit 10 opens the first outside air passage 12 and the second outside air passage 13 to the same degree, and the dew point temperature Dp of the air supplied to the vehicle interior exceeds the windshield surface temperature Tg, the control unit 50 adjusts the opening of the outside air flow rate adjustment unit 10 so that the second outside air passage 13 side opens more than the first outside air passage 12 side, thereby increasing the airflow of the second outside air passage 13 (step S31 shown in Figure 4) to prevent window fogging.

[0095] <Winter indoor / outdoor air mixing (low airflow) mode> Figure 7 shows an example of operation in the indoor / outdoor air mixing (low airflow) mode during winter (when heating operation is performed). In this case, the indoor / outdoor air switching damper 5 is adjusted to open both the indoor air inlet 4 and the outdoor air inlet 3 at a predetermined airflow ratio. The outdoor air flow rate adjustment unit 10 is adjusted, for example, to close the second outdoor air passage 13 and open the first outdoor air passage 12 to its maximum opening.

[0096] The low-temperature outside air introduced from the outside air inlet 3 passes entirely through the first outside air passage 12 and the first inside air passage 11, and exchanges heat with the high-temperature return air that is discharged outside the vehicle in the total heat exchanger 7. The return air passes through the exhaust passage 15 and is discharged outside the vehicle compartment from the one-way valve 9.

[0097] The outside air that has passed through the total heat exchanger 7 is drawn into the blower unit 6 in a heated state. The inside air circulating inside the vehicle also passes through the second inside air passage 14 and is drawn into the blower unit 6. In the blower unit 6, the outside air and inside air are mixed, and this mixed air is supplied to the air passage 21 of the temperature control unit 20. In heating operation, the temperature control unit 20 does not flow refrigerant through the evaporator 22, but instead allows the mixed air to pass through. Downstream of the evaporator 22, the air mix damper 25 is positioned to close the passage 21A, and the mixed air that has passed through the evaporator 22 passes through the heater core 23, is reheated as needed, and blown into the vehicle interior.

[0098] In the total heat exchanger 7, the outside air is heated by the heat exchange between the outside air and the return air, thus reducing the heating load on the heater core 23. Although the total heat exchanger 7 acts as resistance, in low airflow mode, even if the entire volume of outside air passes through the total heat exchanger 7, the impact on airflow loss is minimal.

[0099] The control unit 50 controls the outside air flow rate adjustment unit 10 based on the windshield surface temperature Tg and the dew point temperature Dp of the air supplied to the vehicle interior. As shown in Figure 7, when the outside air flow rate adjustment unit 10 has the first outside air passage 12 open to its maximum degree, if, for example, the dew point temperature Dp of the air supplied to the vehicle interior exceeds the windshield surface temperature Tg, the control unit 50 adjusts the opening of the outside air flow rate adjustment unit 10 so that the second outside air passage 13 side opens, and increases the airflow rate of the second outside air passage 13 (step S31 shown in Figure 4) to prevent window fogging.

[0100] <Winter indoor / outdoor air mixing (high airflow) mode> Figure 8 shows an example of operation in the winter (when heating operation is performed) indoor / outdoor air mixing (high airflow) mode. In this case, the indoor / outdoor air switching damper 5 is adjusted to open both the indoor air inlet 4 and the outdoor air inlet 3 at a predetermined airflow ratio. In this example, the outdoor air flow rate adjustment unit 10 is also adjusted to open the first outdoor air passage 12 and the second outdoor air passage 13 at an arbitrary airflow ratio.

[0101] The low-temperature outside air introduced through the outside air inlet 3 partially passes through the first outside air passage 12 and the first inside air passage 11, and exchanges heat with the high-temperature return air that is discharged outside the vehicle in the total heat exchanger 7. The return air passes through the exhaust passage 15 and is discharged outside the vehicle compartment from the one-way valve 9.

[0102] Furthermore, some of the low-temperature outside air introduced from the outside air inlet 3 (outside the outside air that passes through the first outside air passage 12) passes through the second outside air passage 13 and bypasses the total heat exchanger 7.

[0103] The outside air that has passed through the total heat exchanger 7 is drawn into the blower unit 6 in a heated state. The blower unit 6 also draws in outside air that has bypassed the total heat exchanger 7, and both are supplied to the airflow passage 21 of the temperature control unit 20. Furthermore, the inside air circulating inside the vehicle passes through the second inside airflow passage 14 and is drawn into the blower unit 6. In the blower unit 6, the outside air and inside air are mixed, and this mixed air is supplied to the airflow passage 21 of the temperature control unit 20.

[0104] In heating operation, the temperature control unit 20 does not pass refrigerant through the evaporator 22, but instead passes mixed air through it. Downstream of the evaporator 22, the air mix damper 25 is positioned to close the flow path 21A, and the mixed air that has passed through the evaporator 22 passes through the heater core 23, is reheated, and blown into the passenger compartment. Since a portion of the outside air is heated by heat exchange with the return air in the total heat exchanger 7, the load on the temperature control unit 20 (reheating load) can be reduced.

[0105] If there is a requirement for high airflow and even with the capacity of the blower unit 6 set to maximum, the amount of outside air that has passed through the total heat exchanger 7 is insufficient to blow into the vehicle cabin, the control unit 50 adjusts the opening of the outside air flow rate adjustment unit 10 so that a portion of the outside air also passes through the second outside air passage 13. Since the outside air passing through the second outside air passage 13 does not suffer airflow losses due to passing through the total heat exchanger 7, the requirement for high airflow can be met. In addition, the opening of the internal / external air switching damper 5 may also be adjusted. That is, for example, the opening may be adjusted so that the opening on the external air inlet 3 side is larger than the internal air inlet 4 side, thereby increasing the amount of outside air introduced. In particular, in internal / external air mixing mode, the amount of outside air introduced is set according to the carbon dioxide concentration inside the vehicle cabin, so to increase the airflow, the amount introduced from the external air inlet 3 is increased.

[0106] When a large amount of outside air is introduced through the outside air inlet 3, the effect of windage loss due to the outside air passing through the total heat exchanger 7 becomes significant. Therefore, when the effect of windage loss becomes significant, the opening degree of the outside air flow rate adjustment unit 10 is adjusted, for example, so that the second outside air flow passage 13 is larger than the first outside air flow passage 12.

[0107] Furthermore, the control unit 50 controls the outside air flow rate adjustment unit 10 based on the windshield surface temperature Tg and the dew point temperature Dp of the air supplied to the vehicle interior. As shown in Figure 8, if the outside air flow rate adjustment unit 10 opens the first outside air passage 12 and the second outside air passage 13 to the same degree, and the dew point temperature Dp of the air supplied to the vehicle interior exceeds the windshield surface temperature Tg, the control unit 50 adjusts the opening of the outside air flow rate adjustment unit 10 so that the second outside air passage 13 side opens more than the first outside air passage 12 side, thereby increasing the airflow of the second outside air passage 13 (step S31 shown in Figure 4) to prevent window fogging.

[0108] <Winter internal air circulation mode> Figure 9 shows an example of operation in the recirculation mode during winter (when heating operation is performed). In this case, the recirculation damper 5 is adjusted to close the outside air inlet 3 and open the recirculation inlet 4 to its maximum opening. In the recirculation mode (when no outside air is introduced), the recirculating air passes through the second recirculation passage 14 from the recirculation inlet 4. Since no outside air is introduced, the recirculation air flow rate adjustment unit 10 is not controlled. Also, the one-way valve 9 is moved to a position that closes the exhaust passage 15.

[0109] <Summer indoor / outdoor air mixing (high airflow) mode> Figure 10 shows an example of operation in the summer (when air conditioning is running) in the mixed indoor and outdoor air (high airflow) mode. In summer, the outdoor air introduced from the outdoor air inlet 3 is hot, and the indoor air circulating in the vehicle interior is cold. The hot outdoor air passing through the total heat exchanger 7 is dehumidified and cooled by heat exchange with the cold return air. In the temperature control unit 20, the air passing through the air passage 21 (air supplied to the vehicle interior) is dehumidified by the evaporator 22 and flows only through the flow path 21A, and air does not pass through the heater core 23. The air in the flow path 21A is blown into the vehicle interior. The rest of the airflow and the operation of the vehicle air conditioning system 1 are the same as in winter. Therefore, Figure 10 will be used to explain the summer indoor / outdoor air mixing (high airflow) mode as a representative example, and explanations for the summer outdoor air introduction (low airflow) mode (see Figure 5), summer outdoor air introduction (high airflow) mode (see Figure 6), and summer indoor / outdoor air mixing (low airflow) mode (see Figure 7) will be omitted.

[0110] Referring to Figure 10, in this case, the opening of the internal / external air switching damper 5 is adjusted so that both the internal air inlet 4 and the external air inlet 3 are opened at a predetermined airflow ratio. In this example, the opening of the external air flow rate adjustment unit 10 is adjusted so that the first external air passage 12 and the second external air passage 13 are at an arbitrary airflow ratio.

[0111] High-temperature outside air introduced through the outside air inlet 3 partially passes through the first outside air passage 12 and the first inside air passage 11, and exchanges heat with the low-temperature return air discharged outside the vehicle in the total heat exchanger 7. The return air passes through the exhaust passage 15 and is discharged outside the vehicle compartment from the one-way valve 9.

[0112] Furthermore, the remaining portion of the high-temperature outside air introduced from the outside air inlet 3 (outside the outside air that passes through the first outside air passage 12) passes through the second outside air passage 13, bypassing the total heat exchanger 7.

[0113] The outside air that has passed through the total heat exchanger 7 is drawn into the blower unit 6 in a cooled state. The blower unit 6 also draws in outside air that has bypassed the total heat exchanger 7, and both are supplied to the airflow passage 21 of the temperature control unit 20. Furthermore, the inside air circulating inside the vehicle passes through the second inside airflow passage 14 and is drawn into the blower unit 6. In the blower unit 6, the outside air and inside air are mixed, and this mixed air is supplied to the airflow passage 21 of the temperature control unit 20.

[0114] During cooling operation, the temperature control unit 20 flows refrigerant through the evaporator 22 and dehumidifies by passing air (in this case, mixed air) through it. Downstream of the evaporator 22, the air mix damper 25 is positioned to close the flow path 21B, so the mixed air that has passed through the evaporator 22 is blown into the passenger compartment via the flow path 21A without passing through the heater core 23.

[0115] If there is a requirement for high airflow and even with the capacity of the blower unit 6 set to maximum, the amount of outside air that has passed through the total heat exchanger 7 is insufficient to blow into the vehicle cabin, the control unit 50 adjusts the opening of the outside air flow rate adjustment unit 10 so that a portion of the outside air also passes through the second outside air passage 13. Since the outside air passing through the second outside air passage 13 does not suffer airflow losses due to passing through the total heat exchanger 7, the requirement for high airflow can be met. In addition, the opening of the inside / outside air switching damper 5 may also be adjusted. That is, for example, the opening may be adjusted so that the outside air inlet 3 side is larger than the inside air inlet 4 side, thereby increasing the amount of outside air introduced.

[0116] When a large amount of outside air is introduced through the outside air inlet 3, the effect of windage loss due to the outside air passing through the total heat exchanger 7 becomes significant. Therefore, when the effect of windage loss becomes significant, the opening degree of the outside air flow rate adjustment unit 10 is adjusted, for example, so that the second outside air flow passage 13 is larger than the first outside air flow passage 12.

[0117] Figure 11 shows another example of this embodiment. In the above embodiment, the case in which the total heat exchanger 7 is rotary is illustrated, but the embodiment is not limited to this, and the total heat exchanger 7 may be a stationary (permeable) total heat exchanger in which partitions and corrugated sheets are alternately stacked, and these stacked corrugated sheets are alternately arranged orthogonally, as shown in Figure 11. The other configurations are the same as in Figure 1, so the explanation will be omitted.

[0118] In this embodiment, if the control panel of the vehicle air conditioning system 1 is operated by a user (occupant) during outside air flow rate adjustment control, that operation takes precedence.

[0119] It should be noted that the vehicle air conditioning system of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. [Explanation of Symbols]

[0120] 1. Vehicle air conditioning system 2 Intake Units 3. Outside air intake 4. Interior air intake 5. Air intake / external air switching damper 5A Oscillating shaft 6. Air blower 6M motor 7 Total heat exchanger 7A axis 7M Motor 8 filters 9 One-way valve 10. Outdoor air flow rate adjustment unit 10A Oscillating shaft 11. First internal airflow channel 12 1st outside air flow path 13 Second outside air flow path 14. Second internal airflow channel 15 Exhaust passage 20 Temperature control section 21 Airflow passage 21A, 21B channel 22 Evaporator 23 Heater core 25 Air Mix Damper 26 Temperature and Humidity Sensor 27. Glass surface temperature sensor 50 Control Unit 51 Air Conditioning Control Unit 52 Indoor / Outdoor Airflow Control Unit 53. Outdoor air flow rate adjustment control unit Dp Dew point temperature Tg windshield surface temperature

Claims

1. An outside air inlet for bringing in outside air, An air intake vent for introducing internal air, An internal / external air switching damper that switches the ratio of internal and external air intake, A blower unit is provided downstream of the aforementioned internal / external air switching damper and supplies air to the passenger compartment, A total heat exchanger is provided between the outside air inlet and the blower, and exchanges heat between the outside air and the return air, which is the internal air that is discharged from the inside of the vehicle to the outside of the vehicle. The first outside air passage through which the outside air introduced from the outside air inlet flows into the total heat exchanger, The outside air introduced from the outside air inlet bypasses the total heat exchanger through a second outside air passage, An outside air flow rate adjustment unit that adjusts the ratio of airflow volume between the first outside air passage and the second outside air passage, A temperature control unit that adjusts the temperature of the air supplied to the vehicle interior, A vehicle air conditioning system comprising a control unit, The control unit controls the outside air flow rate adjustment unit so that the airflow ratio is set to an arbitrary ratio based on the dew point temperature of the air downstream of the total heat exchanger. A vehicle air conditioning system characterized by the following features.

2. The control unit increases the amount of outside air flowing through the first outside air passage when the temperature near the windshield is higher than the dew point temperature and the temperature difference exceeds a predetermined value. The vehicle air conditioning system according to feature 1.

3. The control unit, If the temperature near the windshield is higher than the dew point temperature and the temperature difference is less than or equal to a predetermined value, or if the temperature near the windshield is lower than the dew point temperature, To increase the airflow rate of the outside air flowing through the second outside air passage, The vehicle air conditioning system according to feature 1.

4. The control unit, If the temperature near the windshield is lower than the dew point temperature and the temperature difference exceeds a predetermined value, The temperature control unit is controlled to perform dehumidification. The vehicle air conditioning system according to feature 3.

5. The outside air flow rate adjustment unit is provided downstream of the outside air inlet and upstream of the total heat exchanger. The vehicle air conditioning system according to feature 1.

6. The control unit increases the airflow rate through the second outside air passage when the amount of air supplied to the vehicle interior exceeds a predetermined value. The vehicle air conditioning system according to feature 1.

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