JP2024125913A - Vehicle air conditioning system - Google Patents

Abstract

To provide a vehicle air conditioning system that suppresses a sudden drop in heating temperature by controlling the air blown into the vehicle cabin so that all air has passed through a heater core when switching from HV driving to EV driving.
[Solution] The heating system includes an air conditioner that passes through a heater core 28 through which a heat medium circulates and blows air whose temperature has increased into the vehicle cabin, an air mix damper 26 that changes the mixture ratio of the air that passes through the heater core 28 and is blown into the vehicle cabin and the air that is blown into the vehicle cabin without passing through the heater core 28, and a control unit 56 that controls the air mix damper 26, wherein when switching from HV driving to EV driving, the control unit 56 controls the air mix damper 26 so that all of the air blown into the vehicle cabin is air that has passed through the heater core 28.
[Selected Figure] Figure 1

Description

The present invention relates to an air conditioner for a vehicle, and in particular to an air conditioner installed in a hybrid vehicle.

Conventionally, air conditioners have been used to control the heating of vehicles. For hybrid vehicles that selectively use a driving mode in which the power from the engine is used to drive the vehicle (hereinafter referred to as "HV driving") and a driving mode in which the engine is stopped and only the power from the electric motor is used to drive the vehicle (hereinafter referred to as "EV driving"), vehicle air conditioners tailored to the characteristics of the vehicle have been proposed.

For example, Patent Document 1 discloses a hybrid vehicle that controls an air conditioning system that can selectively implement a heating mode using electricity stored in an electricity storage device and a heating mode using an internal combustion engine as a heat source. The air conditioning system is controlled to prioritize a heating mode using the engine as a heat source during HV driving. This configuration is said to reduce power consumption compared to a case where heating is performed uniformly using electricity stored in an electricity storage device regardless of whether the vehicle is HV driving or EV driving. Also, during EV driving, in which the internal combustion engine is stopped and the vehicle runs on power from an electric motor, heating capacity can be secured without operating the internal combustion engine, so heating control suitable for hybrid vehicles can be achieved.

JP 2015-077852 A

In hybrid vehicles, which use engine waste heat during HV driving and a heater during EV driving to heat the passenger compartment, the engine is used as a heat source to use the heating system during HV driving, so the temperature of the water circulating through the heating system is high. For this reason, such heating systems are set up to take in outside air, mix it with air heated by coolant using the engine as a heat source, and blow the mixed air into the passenger compartment to provide a comfortable temperature for the occupants. Specifically, the degree of mixing of the outside air and the air heated by the coolant is adjusted so that the temperature of the air blown into the passenger compartment is a set temperature. To make this adjustment, the opening of the air mix damper is controlled, and generally, the opening of the air mix damper is widened during HV driving when the water temperature is sufficiently high.

Here, when the air mix damper is open widely, if the engine is stopped and the vehicle switches from HV to EV driving, the temperature of the water circulating through the heating system drops, which can cause the heating temperature to drop suddenly.

Therefore, this specification provides a vehicle air conditioning system that suppresses a sudden drop in heating temperature when switching from HV driving to EV driving.

The vehicle air conditioner disclosed in this specification is a vehicle air conditioner for a hybrid vehicle that uses engine waste heat during HV driving and a heater during EV driving to heat the vehicle interior, and is equipped with a heating system that blows air into the vehicle interior whose temperature has increased by passing through a heater core in which a heat medium circulates, an air mix damper that changes the mixture ratio of air that passes through the heater core and is blown into the vehicle interior and air that does not pass through the heater core and is blown into the vehicle interior, and a control unit that controls the air mix damper, and when switching from HV driving to EV driving, the control unit controls the air mix damper so that all of the air blown into the vehicle interior is air that has passed through the heater core.

With the above configuration, when switching from HV driving to EV driving, all the air blown into the vehicle cabin has passed through the heater core, preventing a sudden drop in heating temperature.

The vehicle air conditioner is also characterized in that, when the target blowing 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 of the air blown into the vehicle cabin is air that has passed through the heater core.

The vehicle air conditioning system is also characterized in that, during HV driving, the control unit controls the mixture ratio of air that passes through the heater core and is blown into the vehicle cabin, and 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 a target blowing temperature.

According to the above configuration, the air blown into the vehicle cabin is controlled based on a comparison between the target blown temperature and the temperature of the air blown into the vehicle cabin, so that the heating system can be used more effectively while preventing a sudden drop in heating temperature.

According to the vehicle air conditioning system disclosed in this specification, when switching from HV driving to EV driving, all the air blown into the vehicle cabin has passed through the heater core, so a sudden drop in heating temperature can be suppressed.

1 is a diagram illustrating an example of a configuration of a vehicle air conditioner; 10 is a flowchart illustrating a process executed by a control unit.

The vehicle air conditioner will now be described with reference to the drawings. Note that the present invention is not limited to the embodiments described herein.

Figure 1 is a schematic diagram showing an example of the configuration of a vehicle air conditioner. In Figure 1, "Up" indicates the upper side of the vehicle. The vehicle air conditioner described with reference to Figure 1 is installed in a hybrid vehicle that uses engine waste heat during HV driving and a heater during EV driving to heat the vehicle interior. The hybrid vehicle in this example employs a two-layer heating system that circulates outside air in the upper layer of the vehicle and inside air in the foot area, which will be described later. The vehicle air conditioner in this example includes a heating system, an air mix damper, and a control unit, and the control unit controls the air mix damper so that all the air blown into the vehicle interior has passed through the heater core. The heating system, air mix damper, and control unit will be described in detail later.

The hybrid vehicle in this example equipped with the vehicle air conditioning system has an air duct 10. As shown in FIG. 1, the air duct 10 has an inside air intake 12 and an outside air intake 14. The inside air intake 12 takes in air from within the vehicle cabin, and takes in inside air from openings provided at the front and rear of the vehicle cabin. The outside air intake 14 takes in outside air from outside the vehicle, and usually takes in outside air from an opening provided at the front of the vehicle.

A blower 16 is disposed inside the inside air intake 12 and the outside air intake 14 of the ventilation duct 10. The blower 16 has a fan 20 driven by a motor 18, and air (i.e., inside air and outside air) is taken in from the inside air intake 12 and the outside air intake 14 by the rotation of the fan 20. A damper 22 is disposed inside the inside air intake 12 and the outside air intake 14. The damper 22 adjusts the opening degree of the inside air intake 12 and the outside air intake 14, and can be adjusted from 100% inside air (0% outside air) to 0% inside air (100% outside air) depending on the position of the damper 22. The blower 16 and the damper 22 may be provided separately for inside air and outside air, so that they can be controlled independently.

An evaporator 24 is disposed 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 formed by circulating a heat medium through this circulation path.

An air mix damper 26 is disposed 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 disposed 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 in 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 in the ventilation duct 10 passes through the heater core 28. In other words, the air mix damper 26 can change the mixture ratio between the air that passes through the heater core 28 and the air that does not pass through the heater core 28 by moving from the upper closed position to the lower closed position.

The heater core 28 is provided with a circulation path including a circuit through which water is circulated during EV driving, in which the water pump (WP) 30 and the heater 32 are connected, and a circuit through which water is circulated during HV driving, in which the WP 34 and the engine 36 are connected, forming a heating system. In this heating system, valves 38a and 38b are provided in each of the circuits for EV driving and HV driving. The water circulation is controlled by opening and closing the valves 38a and 38b. In this example, water is circulated as a heat medium in the circulation path of this heating system, and air whose temperature has increased by passing through the heater core 28 is blown into the vehicle cabin. The heater 32 is, for example, an electric heater, and heats the circulating water. The temperature of the circulating water is measured by a water temperature sensor 40.

Three outlets are provided downstream of the heater core 28: a foot-side outlet 42, a passenger-side outlet 44, and a defrost-side outlet 46. The foot-side outlet 42 blows air from inside the ventilation duct 10 toward the feet of the driver's and passenger's seats. The passenger-side outlet 44 blows air toward the upper bodies of the driver's and passenger's seats. The defrost-side outlet 46 blows air from the bottom to the top of the inside of the windshield.

A foot-side damper 48 is provided at the foot-side outlet 42, an occupant-side damper 50 at the occupant-side outlet 44, and a defrost-side damper 52 at the defrost-side outlet 46, and this allows control of the air blown out from the ventilation duct 10. Here, 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 drive unit 54.

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, 52 on the blowing side), the heating of the heater 32, etc. The control unit 56 is supplied with temperatures from an inside air sensor 58 provided near the inside air intake 12, an outside air sensor 60 provided near the outside air intake 14, and a water temperature sensor 40 provided in the water circulation path to the heater core 28. In addition, a solar radiation sensor 62 that measures the intensity of outside light entering the passenger compartment is provided near the windshield glass, and this detection value is also supplied to the control unit 56. Furthermore, the hybrid vehicle of this example equipped with a vehicle air conditioning system is provided with a control panel 64 that accepts inputs from the occupant regarding the temperature setting in the passenger compartment, switching between outside air mode, inside air mode, and inside/outside air mixed mode, and selection of the air outlet, etc., and an operation signal from the control panel 64 is supplied to the control unit 56.

Regarding the intake of inside and outside air, when the damper 22 fully closes the outside air intake 14 and fully opens the inside air intake 12, it is the inside air mode (damper 22: dashed line position), and when the damper 22 fully opens the outside air intake 14 and fully closes the inside air intake 12, it is the outside air mode (damper 22: sandy position). And when the damper 22 is positioned between the inside air mode and the outside air mode, it is the inside/outside air mixed mode.

Next, the temperature control of the heating system performed by the control unit 56 will be described. The control unit 56 controls the damper 22, air mix damper 26, heater 32, etc. based on the set temperature set on the control panel 64, the settings for inside air, outside air, and inside/outside air mode, the selection of the air outlet, and the detection values of the various sensors described above.

The control unit 56 also calculates the target blowing temperature based on the vehicle interior temperature, the set vehicle interior temperature, the detection values of the various sensors described above, and the like. Which outlet to blow air from is determined based on the settings on the control panel 64. The air volume will also be the air volume set on the control panel 64, but if the air volume is set automatically, it can be determined according to the heat required to heat the vehicle interior. For example, the higher the target blowing temperature, the larger the air volume can be set.

When the amount of heat that can be supplied for the required heating is insufficient, the control unit 56 determines that the state should transition to MAXHOT. Then, the control unit 56 controls the air mix damper 26 to set it so that the entire amount of air blown into the vehicle cabin passes through the heater core 28. In other words, when the entire amount of air can pass through the heater core 28 under conditions such as the required air volume, the control unit 56 switches to the MAXHOT state. Note that in this example, the state in which the entire amount of air introduced into the ventilation duct 10 and blown into the vehicle cabin passes through the heater core 28 is called the "MAXHOT state," and other cases are called the "air mix state."

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) will be further explained below with reference to the operation of the air mix damper 26 and Figure 2.

2 is a flowchart explaining the processing procedure executed by the control unit. First, the control unit 56 judges whether the hybrid vehicle in this example has transitioned from HV driving to EV driving (S10). When the control unit 56 judges that the hybrid vehicle has transitioned from HV driving to EV driving (Yes in S10), it compares the target blowing temperature with the temperature of the air blown into the vehicle cabin as heating (hereinafter referred to as the "heating blowing temperature" as appropriate) (S12). On the other hand, when the control unit 56 judges that the hybrid 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 blowing temperature based on the detection values of various sensors. In addition, the blowing temperature from the heating is supplied to the control unit 56 from the sensors located near the foot side outlet 42 and the passenger side outlet 44. In FIG. 1, the foot side outlet 42 side is indicated as sensor 66, and the passenger side outlet 44 side is indicated as sensor 68. When the control unit 56 determines that the target blowing temperature is equal to or higher than the blowing temperature from the heater (Yes in S12), it controls the air mix damper 26 to transition to the MAXHOT state (i.e., all air blown into the vehicle cabin is air that has passed through the heater core 28) (S14). On the other hand, when the control unit 56 determines that the target blowing temperature is lower than the blowing temperature from the heater (No in S12), it does not control the air mix damper 26 (S16) and ends the process.

In addition to the above series of processes, in step S14, the control unit 56 may transition the heating system to a two-layer inside/outside air system. Here, as described above, the hybrid vehicle of this example equipped with a vehicle air conditioner employs a two-layer inside/outside air heating system. The two-layer inside/outside air system circulates outside air in the upper layer of the vehicle and inside air in the foot area. This system can ensure anti-fogging properties and keep the occupants fresh by using fresh, low-temperature outside air, while improving heating performance by blowing warm inside air to the feet. As described above, the control unit 56 controls the switching between the outside air mode, the inside air mode, and the inside/outside air mixed mode. In general, the purpose of the control unit 56 controlling the inside/outside air system to have two layers is to deal with a shortage of heat source. That is, in the case of HV driving, the engine is used as a heat source to use 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 shortage of heat source, so the load on the heater 32 is high. When transitioning from HV driving to EV driving, as in this example, the temperature of the water circulating through the heating system generally drops, causing a sudden drop in the heating temperature. In addition, the water temperature must be increased by the heater 32, which increases power consumption. To deal with this situation, in this example, the control unit 56 controls the air mix damper 26 to transition to the MAXHOT state, but at the same time, the control unit 56 may transition the heating system to a two-layer indoor/outdoor air state.

Next, the operation of the air mix damper 26 will be further explained. The air mix damper 26 controls the amount of air passing through the heater core 28. More specifically, in order to bring the temperature of the air blown from the heater closer to the target temperature of the air blown from the heater, it is necessary to control the proportion of air passing through the heater core 28 by the air mix damper 26. In EV driving, the temperature of the water circulating in the heating system generally drops due to a lack of heat source. Therefore, the control unit 56 fully closes the upper passage of the air mix damper 26 and controls the direction of the air flow so that the entire amount of the air introduced passes through the heater core 28. That is, the control unit 56 transitions to the MAXHOT state. In this way, by transitioning the state from the air mix state normally performed by the heating system in HV driving to the MAXHOT state under the control of the control unit 56, a sudden drop in the heating temperature can be suppressed.

Note that the above explanation is merely an example, and the vehicle air conditioning device disclosed in this specification is configured so that when switching from HV driving to EV driving, the control unit controls the air mix damper so that all air blown into the vehicle cabin has passed through the heater core. Therefore, other configurations of the vehicle air conditioning device may be changed as appropriate.

For example, in the processing procedure described with reference to FIG. 2, the control unit 56 compares the target blowing temperature with the blowing temperature from the heater, and when the target blowing temperature is equal to or higher than the blowing temperature from the heater, controls the air mix damper 26 to transition to the MAXHOT state, but this is not limited thereto. The control unit 56 may control the air mix damper 26 to transition to the MAXHOT state when it is determined that the vehicle has transitioned from HV driving to EV driving. Furthermore, the control unit 56 may control the mixture ratio of air passing through the heater core 28 and air not passing through the heater core 28 by the air mix damper 26, based on the comparison between the target blowing temperature and the blowing temperature from the heater, in order to bring the blowing temperature from the heater closer to the target blowing temperature.

26 air mix damper, 28 heater core, 30, 34 water pump, 32 heater, 36 engine, 56 control unit.

Claims (3)

A vehicle air conditioning device for a hybrid vehicle that uses engine waste heat during HV driving and uses a heater during EV driving to heat the vehicle interior,
a heating system that blows air whose temperature has been increased by passing through a heater core in which a heat medium circulates into the vehicle interior;
an air mix damper that changes a mixture ratio of air that passes through the heater core and is blown into the vehicle compartment and air that does not pass through the heater core and is blown into the vehicle compartment;
A control unit for controlling the air mix damper;
Equipped with
The control unit controls the air mix damper when the HV driving is switched to the EV driving, so that all of the air blown into the vehicle compartment is air that has passed through the heater core.
1. A vehicle air conditioning system comprising: When the target blown-out temperature is equal to or higher than a temperature of the air blown into the vehicle compartment, the control unit controls the air mix damper to make all of the air blown into the vehicle compartment air that has passed through the heater core.
2. The vehicle air conditioning system according to claim 1. The control unit controls a mixture ratio of air that passes through the heater core and is blown into the vehicle compartment and air that does not pass through the heater core and is blown into the vehicle compartment by the air mix damper so that the temperature of the air that is blown into the vehicle compartment becomes a target blowing temperature during the HV running.
2. The vehicle air conditioning system according to claim 1.

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