Vehicle air conditioning switching device and vehicle

Abstract

This system suppresses the rise in carbon dioxide concentration inside the vehicle while also minimizing the introduction of excessive outside air before entering the tunnel. [Solution] A vehicle air conditioning switching device having an internal air circulation mode for circulating air inside the vehicle and an external air intake mode for introducing outside air into the vehicle, comprising: a tunnel information acquisition unit 8A for detecting tunnels in the direction of travel of the vehicle 1; a CO2 concentration estimation unit 8B for estimating the maximum value of carbon dioxide concentration inside the vehicle when the vehicle 1 has traveled through the tunnel before the vehicle 1 enters the tunnel; a first air conditioning switching unit 8Da for setting the vehicle to external air intake mode before the vehicle 1 enters the tunnel if it is determined that the maximum value exceeds a threshold; and a second air conditioning switching unit 8Db for switching to internal air circulation mode when it is determined that the vehicle 1 has entered the tunnel.

Description

Technical Field

[0001] The present invention relates to a vehicle air conditioning switching device for setting an internal air circulation mode for circulating air in the vehicle interior and an outside air introduction mode for introducing outside air into the vehicle interior, and a vehicle equipped with the vehicle air conditioning switching device.

Background Art

[0002] As a vehicle air conditioning switching device mounted on a vehicle, for example, there is a device described in Patent Document 1. Patent Document 1 describes that switching between an internal air circulation mode and an outside air introduction mode is performed based on the inclination angle of the road surface on which the vehicle travels. Further, Patent Document 1 describes that when entering a tunnel, the air conditioning device of the vehicle is automatically switched from the outside air introduction mode to the internal air circulation mode.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technique described in Patent Document 1 is a technique for automatically switching between an internal air circulation mode and an outside air introduction mode according to the current outside air environment (atmospheric state of outside air) of the traveling vehicle and changes in the outside air environment. Here, when traveling in a tunnel, the internal air circulation mode is set, but if the internal air circulation has been continued before entering the tunnel, there is a risk that the carbon dioxide concentration in the vehicle interior will increase while the vehicle is traveling in the tunnel. On the other hand, if outside air introduction is always performed before entering the tunnel, the longer the outside air is introduced, for example, in winter, the temperature in the vehicle interior will decrease, and the passengers may feel dissatisfied.

[0005] The present invention aims to suppress the rise in carbon dioxide concentration inside the vehicle cabin while preventing unnecessary introduction of outside air before entering the tunnel. [Means for solving the problem]

[0006] To solve the problem, one aspect of the present invention has an internal air circulation mode that circulates the air inside the vehicle's cabin and an external air intake mode that introduces external air into the cabin. Before the vehicle enters a tunnel located in the direction of travel, the maximum value of carbon dioxide concentration inside the cabin inside the tunnel is estimated if the vehicle were to travel through the tunnel. If it is determined that the estimated maximum value exceeds a threshold, the system is set to external air intake mode before the vehicle enters the tunnel, and when it is determined that the vehicle has entered the tunnel, the system is set to internal air circulation mode. [Effects of the Invention]

[0007] According to an aspect of the present invention, it is possible to suppress the rise in carbon dioxide concentration inside the vehicle cabin while entering a tunnel, while also suppressing the introduction of excessive outside air before entering the tunnel. This makes it possible to suppress the introduction of excessive outside air into the vehicle cabin in driving environments where it is undesirable to bring too much outside air into the vehicle cabin, such as during cold winter months or hot summer months. Moreover, it is also possible to suppress the carbon dioxide concentration inside the vehicle cabin while driving inside a tunnel. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram illustrating the configuration of a process in a vehicle according to an embodiment of the present invention. [Figure 2] This figure shows an example of the processing flow according to this embodiment. [Figure 3] This is an example of a time chart in this embodiment. [Figure 4] This is an example of a time chart for modified example 2. [Figure 5] This is an example of a time chart for modified example 3. [Figure 6] This is an example of a time chart for modified example 4. [Modes for carrying out the invention]

[0009] Next, embodiments of the present invention will be described with reference to the drawings. In the following description, "vehicle" refers to a private vehicle, but the vehicle of the present invention is not limited to a private vehicle. The present invention is applicable to any vehicle that has a passenger compartment capable of forming an enclosed space and is capable of traveling on a road. As shown in Figure 1, the vehicle 1 of this embodiment includes a navigation device 2, an air conditioning system 3 for regulating the air quality inside the vehicle, and a vehicle air conditioning switching device 8. Figure 1 also shows the functional parts of a modified example described later.

[0010] (Navigation device 2) The navigation device 2 has map information 2A of the road surface being traveled. The map information 2A is updated as needed by accessing an external server 10, for example, via wireless communication. The map information 2A is stored in a recording medium of the vehicle 1. The navigation device 2 can, for example, determine the optimal route from the current location to the destination, or perform map matching processing to position the current location on a map, based on the operation of the occupants. In this embodiment, the navigation device 2 acquires information about tunnels in the direction of travel of the vehicle 1 based on the current position and direction of travel of the vehicle 1, in response to a command from the vehicle air conditioning switch 8. The navigation device 2 is configured to supply the acquired tunnel information to the vehicle air conditioning switch 8. The tunnel information may also be acquired from an external device outside the vehicle, such as by wireless communication.

[0011] (Air conditioner 3) The air conditioning unit 3 has two operating modes for air conditioning: an internal air circulation mode (internal air circulation operation) that circulates the air inside the vehicle cabin, and an external air intake mode (external air intake operation) that introduces outside air into the vehicle cabin. In the outside air intake mode, the air conditioning unit 3 is configured to introduce outside air into the air conditioning duct from an outside air intake port using, for example, a fan device, and to blow the introduced outside air into the vehicle interior through an outlet. Furthermore, in the outside air intake mode, the air conditioning unit 3 of the present invention can also ventilate the vehicle by automatically opening the windows to introduce outside air into the vehicle interior. In the internal air circulation mode, the air conditioning unit 3 is configured to draw in air from the vehicle interior into the air conditioning duct from an intake port using, for example, a fan device, and to blow the drawn-in air into the vehicle interior through an outlet.

[0012] Furthermore, the air conditioning system 3 includes an air conditioning device that heats or cools the air in the air conditioning duct to a predetermined temperature using known air conditioning control means. In addition, switching between the outside air introduction mode and the internal air circulation mode via the air conditioning duct can be done, for example, by a damper device installed in the air conditioning duct. The air conditioning unit 3 is configured to switch the operating mode between internal air circulation mode and external air intake mode based on the operation of an operator by the occupant or a command from the vehicle's air conditioning switching device 8. Note that the air conditioning unit 3 can employ any known configuration as long as it is capable of switching between internal air circulation mode and external air intake mode in response to a command. Furthermore, the air conditioning unit 3 does not necessarily have an external air intake function via automatic opening and closing of windows.

[0013] In this embodiment, when the air conditioning system 3 receives a command from the vehicle air conditioning switching device 8 to set to outside air intake mode, the following processing is performed. Specifically, if the air conditioning system 3 is stopped, the air conditioning system 3 is started and outside air is introduced through the air conditioning duct. If the current air conditioning operation is in internal circulation mode, the system switches to outside air intake through the air conditioning duct by switching the damper. Furthermore, if the current air conditioning operation is in outside air intake mode via the air conditioning duct, the system further promotes outside air intake by automatically opening the windows. For example, the driver's side window is opened about halfway. At this point, after switching to outside air intake mode via the air conditioning duct, it is preferable to continuously measure the carbon dioxide concentration inside the vehicle and, if no improvement is observed, further control to promote outside air intake by automatically opening the windows. Furthermore, if it is determined that the carbon dioxide concentration inside the vehicle has not improved even after promoting ventilation (outside air intake) by opening the driver's side window about halfway, the system may be controlled as follows. In other words, the system may be controlled to automatically change the degree to which the windows are opened in stages, such as opening the driver's side window completely, then opening the passenger side window halfway, and finally opening the passenger side window completely, until the carbon dioxide concentration inside the vehicle improves.

[0014] Furthermore, in the air conditioning system 3 of this embodiment, when a command to set to internal air circulation mode is received from the vehicle air conditioning switching device 8, the following processing is performed. Specifically, if the air conditioning system 3 is stopped, the air conditioning system 3 is started and internal air is circulated through the air conditioning duct (air conditioning started state). Also, if the air conditioning system 3 is in outside air intake mode, the damper is switched to circulate internal air through the air conditioning duct (air conditioning started state). At this time, if the windows were automatically opened, the system also automatically closes the windows. Furthermore, it is preferable that information such as the status and changes of the air conditioning be displayed on a notification device 7, such as an in-vehicle display.

[0015] (Vehicle air conditioning switching device 8) The vehicle air-conditioning switching device 8 of this embodiment is a device for supplying commands to the air-conditioning device 3 to automatically set the operating mode of the air-conditioning device 3, such as automatic switching. The vehicle air-conditioning switching device 8 includes a tunnel information acquisition unit 8A, a CO2 concentration estimation unit 8B, and an air-conditioning switching unit 8D. The air-conditioning switching unit 8D includes a first air-conditioning switching unit 8Da and a second air-conditioning switching unit 8Db.

[0016] <Tunnel information acquisition unit 8A> The tunnel information acquisition unit 8A detects a tunnel existing ahead in the traveling direction of the vehicle 1. The tunnel information acquisition unit 8A of this embodiment acquires tunnel information from the navigation device 2, and based on the acquired information, detects the presence or absence of a tunnel ahead in the travel. The tunnel information is, for example, the travel distance from the current position or reference position of the vehicle 1 to the tunnel entrance and the length of the tunnel. The tunnel to be detected is a tunnel in which the entrance of the tunnel exists within a preset detection distance along the road from the current position of the vehicle 1. The current position of the vehicle 1 may be acquired by a GPS device or the like.

[0017] <CO2 concentration estimation unit 8B> The CO2 concentration estimation unit 8B performs a process of estimating the maximum concentration MC, which is the maximum value of the carbon dioxide concentration in the vehicle interior in the tunnel when the vehicle 1 travels in the tunnel, before the vehicle 1 enters the tunnel detected by the tunnel information acquisition unit 8A. The CO2 concentration estimation unit 8B of this embodiment estimates the maximum concentration MC when the tunnel information acquisition unit 8A determines that a tunnel has been detected. The maximum concentration MC is calculated, for example, by the following formula (1). In this embodiment, the maximum concentration MC can be estimated by referring to at least the carbon dioxide concentration in the vehicle interior, the information of the passengers in the vehicle interior, and the ventilation state in the vehicle to estimate the maximum value MC of the carbon dioxide concentration. MC = C2 + ((L1 + L2) / V)×A - (L2 / V)×B ···(1) Here, C2: The carbon dioxide concentration in the vehicle interior at the current time (starting position) for calculating the maximum concentration MC L1: The length of the tunnel L2: Calculate the highest concentration based on the distance from the current location to the tunnel entrance. V: Average speed of vehicle 1 A: Increase in carbon dioxide concentration per unit time inside the vehicle (ppm / hour) B: Decrease in carbon dioxide concentration per unit time inside the vehicle (ppm / hour) That is the case.

[0018] Vehicle 1 of this embodiment is equipped with a CO2 sensor 4 that measures the carbon dioxide concentration in the passenger compartment. The carbon dioxide concentration C2 can be obtained from the measurement value of the CO2 sensor 4. Vehicle 1 of this embodiment is also equipped with a vehicle speed sensor 5 that detects the vehicle speed. The average speed V of vehicle 1 can be calculated based on the history of measurement values ​​from the vehicle speed sensor 5. The tunnel length L1 can be obtained from tunnel information acquired from the navigation device 2. The distance L2 can be determined by calculating the distance traveled to the tunnel entrance based on the tunnel information acquired from the navigation device 2.

[0019] The carbon dioxide concentration inside the vehicle cabin increases primarily due to the exhalation of the occupants. Therefore, the increase A can be calculated by estimating the amount of carbon dioxide increase due to the occupants present in the vehicle cabin. Similarly, the decrease B can be calculated by estimating the amount of carbon dioxide decrease based on the outside air intake (ventilation) status detected by the ventilation state detection unit 8C.

[0020] In this embodiment, the vehicle 1 includes an occupant detection unit 6 and a ventilation state detection unit 8C. <Crew detection unit 6> The passenger detection unit detects information about the occupants inside the vehicle. This passenger information includes, for example, the number of occupants and the attributes of each occupant. Occupant attributes include, for example, whether the occupant is an adult or a child. The number of occupants can be detected, for example, from seat belt usage information for each seat or from seat sensors (load sensors) installed in each seat. Furthermore, the occupant's attribute, such as whether they are an adult or a child, can be estimated from the degree to which the seat belt is wrapped and the occupant's weight. In addition, the vehicle 1 of this embodiment may be equipped with a camera that images the interior of the vehicle as the passenger detection unit. The number of occupants and the attributes of each occupant can then be obtained based on the images captured by the camera using a known image analysis method. In this case, the occupant's attributes can be determined with greater accuracy. Here, the only information needed about the crew is the number of people inside the vehicle.

[0021] [How to find the increase amount A] The average amount of carbon dioxide increase due to human exhalation is calculated in advance and stored in a memory unit. Then, the increase amount A can be calculated by multiplying the average amount of carbon dioxide increase by the number of occupants. Alternatively, the average amount of carbon dioxide increase due to exhalation may be calculated individually for adults and children, and the increase amount A may be calculated based on these averages. Furthermore, the increase amount A may be corrected based on the physiological state of the occupants, such as sweating. The increase amount A can be calculated using known methods.

[0022] <Ventilation state detection unit 8C> The ventilation state detection unit 8C determines the ventilation state inside the vehicle. The ventilation state inside the vehicle is determined by whether the windows are open or whether outside air is being introduced through the ducts. Based on information from the air conditioning unit 3, the ventilation state detection unit 8C determines whether the outside air introduction mode is only through the air conditioning ducts, or whether air is being introduced by opening the windows in addition to the outside air.

[0023] [Regarding the calculation of carbon dioxide reduction amount B] The carbon dioxide reduction amount B is determined as follows, based on the determination of the ventilation state detection unit 8C, when it is determined that the outside air introduction mode is only outside air introduction via the air conditioning duct. For example, the correlation between vehicle speed and duct opening degree, with the amount of carbon dioxide reduction due to outside air intake via the air conditioning duct, is determined in advance, and the first carbon dioxide reduction amount B1 is calculated based on this correlation. Then, the first carbon dioxide reduction amount B1 is set as the carbon dioxide reduction amount B. Also, based on the determination of the ventilation state detection unit 8C, if the outside air intake mode is outside air intake via the air conditioning duct and air intake by opening a window, the carbon dioxide reduction amount B is determined as follows, for example. For example, the correlation between vehicle speed and window opening degree, with the amount of reduction due to opening a window, is determined in advance, with the amount of vehicle speed and window opening degree, with the amount of carbon dioxide reduction due to opening a window. Then, the second carbon dioxide reduction amount B2 due to opening a window is calculated based on this correlation. Then, the value obtained by adding the second carbon dioxide reduction amount B2 to the first carbon dioxide reduction amount B1 is set as the carbon dioxide reduction amount B. Note that each correlation can be determined by experiment or theoretical formula.

[0024] <First air conditioning switching unit 8Da> The first air conditioning switching unit 8Da determines that the maximum concentration MC estimated by the CO2 concentration estimation unit 8B exceeds a threshold, and performs a process to set the vehicle 1 to outside air intake mode before the vehicle enters the tunnel. The threshold is, for example, 1,000 ppm. Here, the thresholds used in this embodiment may be the same value or different values ​​from each other. In this embodiment, the first air conditioning switching unit 8Da determines that the maximum concentration MC exceeds a threshold and outputs a command to the air conditioning unit 3 to switch to the outside air intake mode. As a result, the operating mode of the air conditioning unit 3 is set to the outside air intake mode. The switch to the outside air intake mode is performed, for example, when the distance from the target tunnel entrance reaches a predetermined set distance.

[0025] <Second air conditioning switching unit 8Db> The second air conditioning switching unit 8Db, upon determining that vehicle 1 has entered the tunnel, outputs a command to switch to the internal air circulation mode if the current air conditioning mode is the outside air intake mode. This switches the operation of the air conditioning unit 3 to the internal air circulation mode. Detection of entry into the tunnel may be based on information from the navigation device 2, or it may be detected by other equipment such as a camera that acquires information in the direction of travel ahead.

[0026] (others) In this embodiment, as shown in Figure 2, when the tunnel information acquisition unit 8A detects a tunnel ahead in the direction of travel (Step S1: YES), the CO2 concentration estimation unit 8B calculates the maximum value MC of carbon dioxide concentration during tunnel travel. When the first air conditioning switching unit 8Da determines that this maximum value exceeds a threshold, it determines that outside air introduction is necessary (Step S2: YES) and outputs a command to the air conditioning unit 3 to set the outside air introduction mode, and the operating mode controlled by the air conditioning unit 3 switches to the outside air introduction mode (Step S5). Furthermore, when the second air conditioning switching unit 8Db determines that the vehicle 1 has entered a tunnel (Step S7: YES), it outputs a command to the air conditioning unit 3 to set the internal air circulation mode, and the operating mode controlled by the air conditioning unit 3 switches to the internal air circulation mode (Step S9).

[0027] As a result of the above processing, in this embodiment, as shown in the time chart in Figure 3, if the initial carbon dioxide concentration at the start of control is high, and the vehicle enters the tunnel while continuing in internal air circulation mode, the carbon dioxide concentration in the tunnel will exceed the threshold (see CC1). In contrast, in this embodiment, outside air is introduced into the vehicle cabin before entering the tunnel, which suppresses the carbon dioxide concentration from exceeding the threshold in the tunnel (see CC2). On the other hand, if the carbon dioxide concentration at the start of control is low (see CC3), the carbon dioxide concentration in the tunnel will not exceed the threshold even if the vehicle enters the tunnel while continuing in internal air circulation mode, so in this embodiment, outside air is not introduced before entering the tunnel.

[0028] Tunnels are enclosed areas with an outside air atmosphere where opening windows for ventilation is undesirable. In this embodiment, if it is determined that such a tunnel exists in the direction of travel, outside air is introduced into the vehicle cabin for ventilation only if it is estimated that the carbon dioxide concentration inside the vehicle cabin will exceed a predetermined level while driving through the tunnel. In other words, in this embodiment, if it is determined that ventilation is unnecessary, outside air is not introduced before entering the tunnel. Thus, in this embodiment, in order to avoid introducing outside air inside the tunnel as much as possible, the system switches to introducing outside air before entering the tunnel and uses internal air circulation inside the tunnel. However, if the threshold is not exceeded inside the tunnel even if internal air circulation is continued, the system does not switch to introducing outside air before entering the tunnel. This makes it possible in this embodiment to suppress the introduction of outside air into the vehicle cabin more than necessary in outside air environments where it is undesirable to bring too much outside air into the vehicle cabin, such as during cold winter months or hot summer months. Moreover, it is also possible to suppress the carbon dioxide concentration inside the vehicle cabin while driving through a tunnel.

[0029] (modified version) The vehicle air conditioning switching device 8 of this embodiment may have one or more processing functional units selected from the following multiple modifications. (1) Variation 1 As shown in Figure 1, the vehicle air conditioning switching device 8 may also have a second CO2 concentration estimation unit 8E and an additional ventilation unit 8F. <Second CO2 concentration estimation unit 8E> The second CO2 concentration estimation unit 8E is a processing unit that is executed while the vehicle is traveling through the tunnel and estimates the maximum value MC2 of the carbon dioxide concentration inside the vehicle cabin within the tunnel. The maximum value MC2 is calculated, for example, by the following equation (2). MC2 = C2 + (A × (L3 / V) ... (2) Here, L3 is the distance from the current location to the tunnel exit. L3 can be obtained from the tunnel information.

[0030] <Additional ventilation section on the 8th floor> When the additional ventilation unit 8F determines that the maximum value MC2 exceeds the threshold, it notifies the vehicle that additional ventilation will be performed by introducing outside air into the vehicle cabin while the vehicle is traveling through the tunnel, and then performs the additional ventilation while the vehicle is traveling through the tunnel. Additional ventilation can be performed by temporarily switching the operating mode of the air conditioning unit 3 to outside air introduction mode or by temporarily automatically opening the windows while the vehicle is traveling through the tunnel. The duration of the additional ventilation is set to be longer the larger the difference between the maximum value MC2 and the threshold, for example.

[0031] In this modified version 1, even though outside air was introduced before entering the tunnel, if it is estimated that the carbon dioxide concentration inside the tunnel will exceed a threshold, additional ventilation can be automatically performed midway through the tunnel. Furthermore, the crew can be notified of the additional ventilation by the notification device 7.

[0032] (2) Modification example 2 The vehicle air conditioning switching device 8 may also have an inlet concentration estimation unit 8G, as shown in Figure 1. <Inlet concentration estimation section 8G> The inlet concentration estimation unit 8G estimates the following when vehicle 1 travels through the entire tunnel in internal air circulation mode, as shown in the time chart CC4 in Figure 4. Specifically, the inlet concentration estimation unit 8G estimates the inlet concentration EC, which is the carbon dioxide concentration at the tunnel entrance, such that the estimated carbon dioxide concentration inside the vehicle at the tunnel exit becomes a threshold (see Q1). The inlet concentration EC can be calculated from the increase amount A and the tunnel length L1 using the following equation (3). EC = threshold - A × L1 / V ... (3)

[0033] In the modified example 2, the timing T1 for setting the first air conditioning switching unit 8Da to the outside air intake mode is set to a position further from the tunnel entrance when the inlet concentration is high compared to when the inlet concentration is low. The timing T1 can be determined, for example, by calculating the estimated carbon dioxide concentration at the tunnel entrance when driving to the tunnel entrance in internal air circulation mode using "C2 + (L2 / V) × A", and then determining it based on the difference ΔC between the calculated value and the inlet concentration, the decrease amount B, and the vehicle speed V. In this modified example 2, as shown in Figure 4, by controlling the timing T1 for setting to outside air intake mode, it is possible to prevent the period of time during which outside air is introduced before entering the tunnel from becoming unnecessarily long.

[0034] (Variation 3) The vehicle air conditioning switching device 8 may have the above-mentioned inlet concentration estimation unit 8G and a third air conditioning switching unit 8Dc, as shown in Figure 1. <Third air conditioning switching unit 8Dc> As shown in Figure 5, the third air conditioning switching unit 8Dc determines the estimated carbon dioxide concentration Q2 at the tunnel entrance if the outside air intake mode set by the first air conditioning switching unit 8Da is continued until the tunnel entrance. If it determines that the carbon dioxide concentration Q2 is lower than the entrance concentration EC, it switches the outside air intake mode set by the first air conditioning switching unit 8Da to the internal air circulation mode before the vehicle 1 reaches the tunnel entrance. The timing T2 for switching to the internal air circulation mode by the third air conditioning switching unit 8Dc can be determined based on the difference between the entrance concentration EC and the carbon dioxide concentration Q2, the increase amount B, and the vehicle speed V.

[0035] In this modified example 3, even if outside air is introduced before entering the tunnel, depending on the estimated carbon dioxide concentration inside the tunnel, the system switches from outside air introduction mode to internal air circulation mode at a timing T2 prior to entering the tunnel. As shown in Figure 5, by controlling the timing T2 at which the outside air introduction mode ends, it is possible to prevent the time period during which outside air is introduced before entering the tunnel from becoming unnecessarily long.

[0036] (Modification 4) The tunnel information acquisition unit 8A detects the presence of multiple tunnels that are close to each other in the direction of travel of vehicle 1. If it determines that ventilation is not completed even when outside air is introduced while driving through two adjacent tunnels, it determines that the two adjacent tunnels are close together. In this case, it becomes possible to determine whether or not they are close together. If ventilation is estimated to be complete, ventilation can be achieved by introducing outside air between the tunnels, so there is no need to adjust multiple tunnels together. Completion of ventilation means that the CO2 inside the tunnel is equivalent to that of the outside air. Simply put, if the length of the road between two adjacent tunnels is less than or equal to a predetermined distance, it may be determined that the two adjacent tunnels are close together.

[0037] In the fourth modification, as shown in Figure 6, a series of tunnels consisting of multiple tunnels that are close to each other are treated as a single tunnel. In other words, in the CO2 concentration estimation unit 8B of the modified example 4, when the tunnel information acquisition unit 8A detects that there are multiple tunnels in a sequence in the direction of travel, it estimates the maximum carbon dioxide concentration inside the vehicle when vehicle 1 travels through multiple tunnels. That is, it estimates not only the carbon dioxide concentration inside the vehicle due to traveling through the most recent tunnel, but also the maximum carbon dioxide concentration inside the vehicle due to traveling through a series of tunnels.

[0038] Then, in the first air conditioning switching unit of the modified example 4, when the CO2 concentration estimation unit 8B determines that the highest carbon dioxide concentration estimated for the series of tunnel runs exceeds a threshold, the following process is performed. That is, the first air conditioning switching unit sets the vehicle 1 to outside air intake mode before the vehicle 1 enters the nearest tunnel among the multiple tunnels. Note that while traveling through two adjacent tunnels, the system is controlled to outside air intake mode (see Figure 6).

[0039] In this modified example 4, as shown in CC7 of Figure 6, when there are multiple tunnels close together in the direction of travel, it is estimated whether the carbon dioxide concentration in all tunnels will exceed the threshold, and the limit value at which the threshold will not be exceeded even if internal air circulation is continued in all adjacent tunnels is estimated. CC6 in Figure 6 is a time chart that considers only the nearest tunnel. The example in Figure 6 shows that while driving through two adjacent tunnels, the system is controlled to outside air intake mode, and the process in Modification 2 is used to determine the inlet concentration EC. Based on this inlet concentration EC, the timing T1 for switching to outside air intake mode at the first air conditioning switching unit 8Da is set.

[0040] As shown in Figure 6, if control is performed for each tunnel, the carbon dioxide concentration in some tunnels may exceed the threshold, as in CC6. However, by adopting Modification 4, it becomes possible to avoid this, as in CC7.

[0041] (Variation 5) The vehicle air conditioning switching device 8 may have an occupant count detection unit. The occupant count detection unit detects the number of occupants in the vehicle. In this embodiment, the occupant detection unit 6 constitutes the occupant count detection unit. However, the occupant detection unit 6 and the occupant count detection unit may be different processing units. In the modified example 5, the timing at which the first air conditioning switching unit 8Da sets to the outside air intake mode is set to a position further from the tunnel entrance when there are many occupants, compared to when there are few occupants. In variation 5, when there are many occupants, switching to outside air intake earlier before entering the tunnel allows for more appropriate intake of outside air than when there are few occupants. [Explanation of symbols]

[0042] 1 vehicle 2 Navigation system 2A Map Information 3 Air conditioner 4 CO2 sensors 5. Vehicle speed sensor 6 Crew detection unit 7. Notification methods 8. Vehicle air conditioning switching device 8A Tunnel Information Acquisition Unit 8B CO2 concentration estimation section 8C Ventilation status detection unit 8D Air conditioning switching section 8Da First air conditioning switching unit 8Db Second air conditioning switching section 8Dc Third air conditioning switching section 8E Second CO2 concentration estimation unit 8F Additional ventilation unit 8G inlet concentration estimator A increase B Decrease amount EC inlet concentration V average speed

Claims

1. The air conditioning system has two operating modes: an internal circulation mode that circulates the air inside the vehicle cabin, and an external air intake mode that introduces outside air into the vehicle cabin. A tunnel information acquisition unit that detects tunnels in the direction of the vehicle's travel, Before a vehicle enters the tunnel detected by the tunnel information acquisition unit, a CO2 concentration estimation unit estimates the maximum value of carbon dioxide concentration inside the vehicle's cabin in the tunnel if the vehicle were to travel through the tunnel. When the CO2 concentration estimation unit determines that the highest carbon dioxide concentration it has estimated exceeds a preset threshold, the first air conditioning switching unit sets the vehicle to the outside air intake mode before the vehicle enters the tunnel. When it is determined that the vehicle has entered the tunnel, if the operating mode at that time is the outside air intake mode, a second air conditioning switching unit switches to the internal air circulation mode, A vehicle air conditioning switching device equipped with the following features.

2. It comprises a CO2 sensor for measuring the carbon dioxide concentration in the vehicle compartment, an occupant detection unit for detecting information about the occupants in the vehicle compartment, and a ventilation state detection unit for determining the ventilation state inside the vehicle. The above CO2 concentration estimation unit estimates the maximum value of the carbon dioxide concentration based on the carbon dioxide concentration inside the vehicle, information on the occupants inside the vehicle, and the ventilation status inside the vehicle. A vehicle air conditioning switching device as described in claim 1.

3. Equipped with a camera capable of imaging the interior of the vehicle, The occupant detection unit acquires the number of occupants in the vehicle and the attributes of each occupant as occupant information based on the images captured by the camera. A vehicle air conditioning switching device as described in claim 2.

4. A second CO2 concentration estimation unit estimates the highest value of carbon dioxide concentration inside the vehicle cabin while the vehicle is traveling through the tunnel, When the second CO2 concentration estimation unit determines that the highest carbon dioxide concentration it has estimated exceeds a preset threshold, it notifies the driver that additional ventilation will be performed by introducing outside air into the vehicle cabin while the vehicle is traveling through the tunnel, and also activates an additional ventilation unit to perform the additional ventilation while the vehicle is traveling through the tunnel. A vehicle air conditioning switching device according to claim 1, comprising:

5. When a vehicle travels through the entire tunnel in internal air circulation mode, the system includes an inlet concentration estimation unit that estimates the inlet concentration, which is the carbon dioxide concentration at the tunnel entrance that is equal to a preset threshold value, when the estimated carbon dioxide concentration inside the vehicle cabin at the tunnel exit is set to the same threshold value. The first air conditioning switching unit described above sets the timing for switching to the outside air intake mode to a position further from the tunnel entrance when the inlet concentration is high compared to when the inlet concentration is low. A vehicle air conditioning switching device according to any one of claims 1 to 4.

6. When a vehicle travels through the entire tunnel in internal air circulation mode, an inlet concentration estimation unit estimates the inlet concentration, which is the carbon dioxide concentration at the tunnel entrance that is such that the estimated carbon dioxide concentration inside the vehicle at the tunnel exit becomes a preset threshold. If the outside air intake mode set by the first air conditioning switching unit is continued until the tunnel entrance, and the estimated carbon dioxide concentration at the tunnel entrance is determined to be lower than the above-mentioned entrance concentration, the third air conditioning switching unit switches the outside air intake mode set by the first air conditioning switching unit to the internal air circulation mode before the vehicle reaches the tunnel entrance. A vehicle air conditioning switching device according to any one of claims 1 to 4, comprising:

7. When the above-mentioned CO2 concentration estimation unit detects that there are multiple tunnels close to the direction of travel, it estimates the maximum carbon dioxide concentration inside the vehicle when the vehicle travels through the multiple tunnels. When the first air conditioning switching unit determines that the maximum carbon dioxide concentration estimated by the CO2 concentration estimation unit exceeds a preset threshold, it switches the vehicle to outside air intake mode before the vehicle enters the first tunnel among several tunnels. A vehicle air conditioning switching device according to any one of claims 1 to 4.

8. The tunnel information acquisition unit determines that two tunnels are close together if it is estimated that ventilation will not be completed when outside air is introduced between the two tunnels. A vehicle air conditioning switching device as described in claim 7.

9. It is equipped with an occupant detection unit that detects the number of occupants inside the vehicle, The first air conditioning switching unit described above sets the timing for switching to the outside air intake mode to a position further from the tunnel entrance when there are many occupants compared to when there are few occupants. A vehicle air conditioning switching device according to any one of claims 1 to 4.

10. A vehicle equipped with the vehicle air conditioning switching device described in claim 1.

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