Vehicle air conditioning system

Abstract

To provide an air conditioner for a vehicle that suppresses rapid lowering of a heating temperature by performing control so that all air blowing out into a cabin passes through a heater core when HV traveling is switched to EV traveling.SOLUTION: An air conditioner for a vehicle includes: a heating system for blowing out air of which temperature has risen by passing through a heater core 28 having a heating medium circulating therein into a cabin; an air mixing damper 26 that changes a mixing ratio between air to be blown out into the cabin through the heater core 28 and air to be blown out into the cabin without passing through the heater core 28; and a control section 56 that controls the air mixing damper 26. The control section 56 controls the air mixing damper 26 when HV traveling is switched to EV traveling so as to cause all of the air to be blown out into the cabin to pass through the heater core 28.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] The present invention relates to a vehicle air conditioner, and particularly to an air conditioner mounted on a hybrid vehicle. [[Background Art]]

[0002] Conventionally, air conditioners have been used to control heating in vehicles. In a hybrid vehicle that selectively applies a travel mode in which power from an engine is used as the driving force of the vehicle (hereinafter appropriately referred to as "HV travel") and a travel mode in which the engine is stopped and only the power of an electric motor is used as the driving force of the vehicle (hereinafter appropriately referred to as "EV travel"), vehicle air conditioners adapted to the characteristics of such vehicles have been proposed.

[0003] For example, Patent Document 1 discloses a hybrid vehicle that controls an air conditioning system capable of selectively implementing a heating mode using electric power stored in a power storage device and a heating mode using an internal combustion engine as a heat source. The air conditioning system is controlled to preferentially implement the heating mode using the engine as a heat source during HV travel. This configuration is said to be capable of suppressing power consumption compared to a case where heating is uniformly performed using the electric power stored in the power storage device regardless of whether the vehicle is in HV travel or EV travel. Furthermore, during EV travel in which the internal combustion engine is stopped and the vehicle travels using the power of the electric motor, heating capacity can be ensured without operating the internal combustion engine, so it is said that heating control suitable for hybrid vehicles can be performed. [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Patent Application Laid-Open No. 2015-077852 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] By the way, in hybrid vehicles, which use waste heat from the engine to heat the cabin during HV driving and a heater during EV driving, the engine is used as the heat source for the heating system during HV driving, so the water temperature circulating in the heating system is high. Therefore, in such heating systems, outside air is taken in and mixed with air heated by the engine's coolant to achieve a comfortable temperature for the occupants, and this mixed air is then blown into the cabin. Specifically, the degree to which the outside air and the air heated by the coolant are mixed is adjusted so that the temperature of the air blown into the cabin reaches the set temperature. To make this adjustment, the opening of the air mix damper is controlled, and generally, during HV driving when the water temperature is sufficiently high, the opening of the air mix damper is widened.

[0006] In this case, when the air mix damper is wide open, if the engine is stopped and the vehicle switches from HV driving to EV driving, the water temperature circulating in the heating system may drop, causing a sudden decrease in the heating temperature.

[0007] Therefore, this specification provides for a vehicle air conditioning system that suppresses a rapid drop in heating temperature when switching from HV driving to EV driving. [Means for solving the problem]

[0008] The vehicle air conditioning system disclosed herein is a vehicle air conditioning system for a hybrid vehicle that uses waste heat from the engine during HV driving and a heater during EV driving to heat the cabin, and comprises: a heating system that blows air that has been heated by passing through a heater core through which a heat transfer medium circulates into the cabin into the cabin; an air mix damper that changes the mixing ratio of the air blown into the cabin after passing through the heater core and the air blown into the cabin without passing through the heater core; and a control unit that controls the air mix damper, wherein the control unit controls the air mix damper when switching from HV driving to EV driving so that all the air blown into the cabin is air that has passed through the heater core.

[0009] With the above configuration, when switching from HV driving to EV driving, all the air blown into the cabin has passed through the heater core, thus suppressing a rapid drop in heating temperature.

[0010] Furthermore, the vehicle air conditioning system is characterized in that, when the target discharge temperature is equal to or higher than the temperature of the air blown into the vehicle cabin, the control unit controls the air mix damper so that all the air blown into the vehicle cabin has passed through the heater core.

[0011] Furthermore, the vehicle air conditioning system is characterized in that, during HV driving, the control unit controls the mixing ratio of the air that passes through the heater core and is blown into the vehicle cabin and the air that does not pass through the heater core and is blown into the vehicle cabin, using the air mix damper, so that the temperature of the air blown into the vehicle cabin becomes the target blown temperature.

[0012] According to the above configuration, the air blown into the vehicle cabin is controlled based on a comparison between the target outlet temperature and the temperature of the air blown into the vehicle cabin. This allows for more effective use of the heating system while suppressing a rapid drop in heating temperature. [Effects of the Invention]

[0013] According to the vehicle air conditioning system disclosed herein, when switching from HV driving to EV driving, all the air blown into the passenger compartment has passed through the heater core, thus suppressing a rapid drop in heating temperature. [Brief explanation of the drawing]

[0014] [Figure 1] This diagram schematically shows an example of the configuration of a vehicle air conditioning system. [Figure 2] This is a flowchart illustrating the processing procedure executed by the control unit. [Modes for carrying out the invention]

[0015] The vehicle air conditioning system will be described below with reference to the drawings. However, the present invention is not limited to the embodiments described herein.

[0016] Figure 1 is a schematic diagram illustrating an example of the configuration of a vehicle air conditioning system. In Figure 1, "Up" indicates the area above the vehicle. The vehicle air conditioning system described with reference to Figure 1 is installed in a hybrid vehicle that uses waste heat from the engine to heat the cabin during HV driving and a heater during EV driving. Furthermore, the hybrid vehicle in this example employs a two-layer heating system that circulates outside air in the upper part of the vehicle and inside air in the footwell, which will be described later. The vehicle air conditioning system in this example comprises a heating system, an air mix damper, and a control unit. The control unit controls the air mix damper so that all the air blown into the cabin has passed through the heater core. Details of the heating system, air mix damper, and control unit will be described later.

[0017] In this example, the hybrid vehicle equipped with a vehicle air conditioning system is provided with a ventilation duct 10. As shown in Figure 1, the ventilation duct 10 has an interior air intake 12 and an exterior air intake 14. The interior air intake 12 takes in air from inside the vehicle, drawing in interior air from openings provided at the front and rear of the vehicle interior. The exterior air intake 14 takes in outside air from outside the vehicle, usually drawing in outside air from an opening provided at the front of the vehicle.

[0018] A blower 16 is positioned inside the inner air intake 12 and outer air intake 14 of the ventilation duct 10. The blower 16 has a fan 20 driven by a motor 18, and the rotation of the fan 20 draws in air (i.e., inner and outer air) from the inner air intake 12 and outer air intake 14. A damper 22 is positioned inside the inner air intake 12 and outer air intake 14. The damper 22 adjusts the opening degree of the inner air intake 12 and outer air intake 14, and the position of the damper 22 allows adjustment from 100% inner air (0% outer air) to 0% inner air (100% outer air). Note that the blower 16 and damper 22 may be provided separately for inner air and outer air, respectively, and controlled independently.

[0019] An evaporator 24 is located downstream of the blower 16 in the ventilation duct 10. A circulation path (not shown) is formed in the evaporator 24. A heat pump system is constructed by circulating a heat transfer medium through this circulation path.

[0020] An air mix damper 26 is located downstream of the evaporator 24. The air mix damper 26 is movable from an upper closed position to a lower closed position. A heater core 28 is located in the lower passage downstream of the air mix damper 26. When the air mix damper 26 is in the lower closed position, 100% of the air flowing into the ventilation duct 10 bypasses the heater core 28. On the other hand, when the air mix damper 26 is in the upper closed position, 100% of the air flowing into the ventilation duct 10 passes through the heater core 28. In other words, the air mix damper 26 can change the mixing ratio of air that passes through the heater core 28 and air that does not pass through the heater core 28 by moving it from the upper closed position to the lower closed position.

[0021] A circulation path is formed in the heater core 28, the circulation path includes a circuit in which water circulates during EV traveling, to which a water pump (WP) 30 and a heater 32 are connected, and a circuit in which water circulates during HV traveling, to which a WP 34 and an engine 36 are connected, thereby constituting a heating system. In this heating system, valves 38a and 38b are provided respectively in the circuit for EV traveling and the circuit for HV traveling. The circulation of water is controlled by opening and closing these valves 38a and 38b. In this example, water circulates as a heat medium in the circulation path of the heating system, and is configured such that air whose temperature has been increased after passing through the heater core 28 is blown out into the vehicle compartment. The heater 32 is, for example, an electric heater that heats the circulating water. The temperature of the circulating water is measured by a water temperature sensor 40.

[0022] On the downstream side of the heater core 28, three air outlets are provided, which are a foot-side air outlet 42, an occupant-side air outlet 44, and a defrost-side air outlet 46. The foot-side air outlet 42 blows air out from the inside of the ventilation duct 10 toward the feet of the occupants in the driver's seat and the front passenger seat. The occupant-side air outlet 44 blows air toward the upper bodies of the occupants in the driver's seat and the front passenger seat. The defrost-side air outlet 46 blows air upward from the lower part of the inner side of the windshield.

[0023] A foot-side damper 48 is provided at the foot-side air outlet 42, an occupant-side damper 50 is provided at the occupant-side air outlet 44, and a defrost-side damper 52 is provided at the defrost-side air outlet 46, so that the blowing of air from the ventilation duct 10 can be controlled. In this example, the opening and closing operations of the foot-side damper 48, the occupant-side damper 50, and the defrost-side damper 52 are controlled by a driving unit 54.

[0024] The control unit 56 controls the opening and closing of the damper 22 and the air mix damper 26, the processing performed by the drive unit 54 (i.e., the opening and closing of the three dampers 48, 50, and 52 on the outlet side), and the heating of the heater 32. The control unit 56 is supplied with temperature data from an interior air sensor 58 located near the interior air intake 12, an exterior air sensor 60 located near the exterior air intake 14, and a water temperature sensor 40 located in the water circulation path to the heater core 28. In addition, a solar radiation sensor 62 is located near the windshield glass to measure the intensity of ambient light entering the passenger compartment, and this detected value is also supplied to the control unit 56. Furthermore, in this example of a hybrid vehicle equipped with a vehicle air conditioning system, a control panel 64 is provided to receive input from the occupant regarding the temperature setting inside the passenger compartment, switching between outside air mode, interior air mode, and mixed interior / exterior air mode, and selection of the air outlet, and operation signals from the control panel 64 are supplied to the control unit 56.

[0025] Regarding the intake of internal and external air, when the external air intake port 14 is fully closed and the internal air intake port 12 is fully open using the damper 22, it becomes internal air mode (damper 22: dashed line position). When the external air intake port 14 is fully open and the internal air intake port 12 is fully closed using the damper 22, it becomes external air mode (damper 22: sandy ground position). Furthermore, when the damper 22 is positioned between the internal air mode and the external air mode, it becomes internal and external air mixed mode.

[0026] Next, the temperature control of the heating system performed by the control unit 56 will be described. Based on the set temperature, indoor air, outdoor air, and indoor / outdoor air mode settings set on the control panel 64, the selection of the air outlet, and the detection values ​​of the various sensors mentioned above, the control unit 56 controls the damper 22, air mix damper 26, heater 32, etc.

[0027] Furthermore, the control unit 56 calculates the target air outlet temperature based on the cabin temperature, the set cabin temperature, and the detection values ​​of the various sensors mentioned above. The outlet from which the air is blown is determined based on the settings in the control panel 64. Similarly, the airflow volume will be set to the volume specified in the control panel 64, but if the airflow volume is set to automatic, it should be determined according to the required amount of heat for heating the cabin. For example, the higher the target air outlet temperature, the greater the airflow volume can be set.

[0028] If the amount of heat that can be supplied for the required heating is insufficient, the control unit 56 determines that it should transition to the MAXHOT state. The control unit 56 then controls the air mix damper 26 to set the entire amount of air blown into the vehicle interior to pass through the heater core 28. In other words, if the entire amount of air can pass through the heater core 28 under conditions such as the required airflow rate, the control unit 56 sets to the MAXHOT state. In this example, the state in which the entire amount of air introduced into the ventilation duct 10 and blown into the vehicle interior passes through the heater core 28 is called the "MAXHOT state," and all other cases are called the "air mix state."

[0029] The control unit 56 controls the air mix damper 26 to completely close the upper passage of the air mix damper 26 (i.e., transition to the MAXHOT state), and this will be further explained below with reference to the operation of the air mix damper 26 and Figure 2.

[0030] Figure 2 is a flowchart illustrating the processing procedure performed by the control unit. First, the control unit 56 determines whether the hybrid vehicle in this example has transitioned from HV driving to EV driving (S10). If the control unit 56 determines that the vehicle has transitioned from HV driving to EV driving (Yes in S10), it compares the target outlet temperature with the temperature of the air blown into the cabin as heating (hereinafter referred to as "heating outlet temperature" as appropriate) (S12). On the other hand, if the control unit 56 determines that the vehicle has not transitioned from HV driving to EV driving (No in S10), it proceeds directly to step S16. As described above, the control unit 56 calculates the target outlet temperature based on the detection values ​​of various sensors. The heating outlet temperature is supplied to the control unit 56 from sensors located near the foot-side outlet 42 and near the occupant-side outlet 44. In Figure 1, the foot-side outlet 42 is shown as sensor 66, and the occupant-side outlet 44 is shown as sensor 68. If the control unit 56 determines that the target outlet temperature is equal to or greater than the outlet temperature from the heater (Yes in S12), it controls the air mix damper 26 to transition to the MAXHOT state (i.e., all the air blown into the passenger compartment is air that has passed through the heater core 28) (S14). On the other hand, if the control unit 56 determines that the target outlet temperature is less than the outlet temperature from the heater (No in S12), it does not control the air mix damper 26 (S16) and terminates the process.

[0031] To add to the above series of processes, in step S14, the control unit 56 may switch the heating system to a two-layer system of internal and external air. Here, as mentioned above, the hybrid vehicle in this example, which is equipped with a vehicle air conditioning system, employs a two-layer system of internal and external air. A two-layer system of internal and external air is a system that circulates outside air in the upper part of the vehicle and internal air at the foot level. This system makes it possible to achieve both the assurance of anti-fogging properties and the maintenance of freshness for occupants by using fresh, low-temperature outside air, and improved heating performance by blowing warm internal air at the foot level. As mentioned above, the control unit 56 controls the switching between the outside air mode, the internal air mode, and the internal and external air mixed mode. Generally, the purpose of the control unit 56 to control the system to be a two-layer system of internal and external air is to address the lack of a heat source. That is, in the case of HV driving, the engine is used as the heat source for the heating system, so the water temperature is sufficiently high, but on the other hand, in the case of EV driving with the engine stopped, there is a lack of a heat source, so the load on the heater 32 is high. As in this example, when transitioning from HV driving to EV driving, the water temperature circulating in the heating system generally decreases, causing a sharp drop in heating temperature. Additionally, the heater 32 needs to reheat the water, increasing power consumption. To address this situation, in this example, the control unit 56 controls the air mix damper 26 to transition to the MAXHOT state. Simultaneously, the control unit 56 may also transition the heating system to a two-layer system using internal and external air.

[0032] Next, the operation of the air mix damper 26 will be explained further. The air mix damper 26 controls the amount of air that passes through the heater core 28. More specifically, in order to bring the discharge temperature from the heater closer to the target discharge temperature, it is necessary to control the proportion of air passing through the heater core 28 using the air mix damper 26. In EV driving, the water temperature circulating in the heating system generally decreases due to insufficient heat source. Therefore, the control unit 56 completely closes the upper passage of the air mix damper 26 and controls the direction of the introduced airflow so that the entire amount of introduced air passes through the heater core 28. In other words, the control unit 56 transitions to the MAXHOT state. In this way, by transitioning the state from the air mix state that the heating system normally operates in HV driving to the MAXHOT state through the control of the control unit 56, a rapid drop in the heating temperature can be suppressed.

[0033] It should be noted that the above explanation is merely an example, and in the vehicle air conditioning system disclosed herein, when switching from HV driving to EV driving, the control unit controls the air mix damper so that all the air blown into the passenger compartment has passed through the heater core. Therefore, other components of the vehicle air conditioning system may be modified as appropriate.

[0034] For example, in the processing procedure described with reference to Figure 2, the control unit 56 compares the target discharge temperature with the discharge temperature from the heater and controls the air mix damper 26 to transition to the MAXHOT state if the target discharge temperature is equal to or greater than the discharge temperature from the heater, but it is not limited to this. The control unit 56 may also control the air mix damper 26 to transition to the MAXHOT state when it determines that the vehicle has transitioned from HV driving to EV driving. Furthermore, based on the comparison between the target discharge temperature and the discharge temperature from the heater, the control unit 56 may control the mixing ratio of air passing through the heater core 28 and air not passing through the heater core 28 using the air mix damper 26 in order to bring the discharge temperature from the heater closer to the target discharge temperature. [Explanation of symbols]

[0035] 26 air mix dampers, 28 heater cores, 30, 34 water pumps, 32 heaters, 36 engines, 56 control units.

Claims

1. A vehicle air conditioning system for a hybrid vehicle that uses waste heat from the engine during HV driving and a heater during EV driving to heat the interior of the vehicle, A heating system that blows air that has been heated by passing through a heater core in which a heat transfer medium circulates into the vehicle interior, An air mix damper that changes the mixing ratio of air that passes through the heater core and is blown into the passenger compartment and air that does not pass through the heater core and is blown into the passenger compartment, A control unit for controlling the air mix damper, Equipped with, The control unit controls the air mix damper to ensure that all the air blown into the vehicle cabin has passed through the heater core when the vehicle switches from HV driving to EV driving and the target discharge temperature is equal to or greater than the temperature of the air blown into the vehicle cabin. A vehicle air conditioning system characterized by the following features.

2. During HV driving, the control unit controls the mixing ratio of the air that passes through the heater core and is blown into the passenger compartment and the air that does not pass through the heater core and is blown into the passenger compartment, using the air mix damper, so that the temperature of the air blown into the passenger compartment reaches the target blown-out temperature. The vehicle air conditioning system according to feature 1.

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