Vehicle air conditioning system

Abstract

To enable desired air volumes to be secured, without enhancing an air-blowing capability, in flowing air continuously into a plurality of heat exchangers in an air conditioning case to perform cooling maximally or warming maximally.SOLUTION: A vehicular air conditioner comprises an air conditioning case in which a plurality of heat exchangers are arranged and also comprises a heat medium circuit that flows a heating medium heated or cooled to the heat exchangers and circulates the medium, the vehicular air conditioner heating or cooling air blown into the air conditioning case and passed through the heat exchangers. The heat medium circuit flows a heat medium in series or in parallel to a first heat exchanger arranged at a windward side in the air conditioning case and a second heat exchanger arranged at a leeward side in the case. The air conditioning case comprises a main air-blowing passage through which air flows continuously to the first heat exchanger and the second heat exchanger and a bypass air-blowing passage through which the air passing through the first heat exchanger flows while bypassing the second heat exchanger, where an air volume adjustment damper for adjusting air-blowing volumes in the bypass air-blowing passage is arranged in the bypass air-blowing passage.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A vehicle air conditioner includes a device unit called an HVAC (Heating, Ventilation, and Air Conditioning) in which a blower unit and an air conditioning case are integrated. Inside the air conditioning case of this vehicle air conditioner, a heat exchanger (a cooler and a heater) for cooling or heating the air in the vehicle interior or outside the vehicle introduced by a blower is provided.

[0003] In a conventional vehicle air conditioner, inside the air conditioning case, an evaporator as a cooler is arranged on the upwind side, and a heater core as a heater is arranged on the downwind side. Between the evaporator and the heater core, an air mix damper is provided to switch whether the air passing through the evaporator bypasses the heater core and flows or mixes the air passing through the evaporator with the air passing through the heater core at a predetermined ratio (see, for example, Patent Document 1 below).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above-described conventional vehicle air conditioner, at maximum cooling, the air passing through the evaporator bypasses the heater core and flows, so the flowing air passes through a single heat exchanger, and the cooled air can be sent into the vehicle interior with a relatively small ventilation resistance.

[0006] In contrast, for thermal management in electric vehicles and the like, a system is being considered in which a heat pump, which acts as a heat source, cools or heats a heat transfer medium such as water or LLC (Long Life Coolant) by absorbing and releasing heat, and then circulates this heat transfer medium to various locations for air conditioning and temperature control. In such a thermal management system, the vehicle air conditioning unit is thought to use a cooler core through which LLC flows as a cooler, which is installed inside the air conditioning case. In this case, the way the LLC flows can be used to switch the function of the heat exchanger between a cooler core and a heater core. Therefore, during maximum cooling, the conventional heater core can be used as a cooler core, and air can be continuously circulated through multiple cooler cores to obtain air cooled to the desired temperature.

[0007] However, with vehicle air conditioning systems in such thermal management systems, during maximum cooling (or maximum heating), the continuous flow of air through multiple heat exchangers increases airflow resistance. As a result, even with the same airflow capacity as conventional vehicle air conditioning systems, it becomes impossible to obtain sufficient airflow during maximum cooling. Furthermore, if this is addressed by increasing the airflow capacity, other problems arise, such as increased power consumption for the blower and increased airflow noise.

[0008] The present invention aims to address these problems. Specifically, in the vehicle air conditioning system in the aforementioned thermal management system, the objective of the present invention is to ensure a desired airflow without increasing the air supply capacity when performing maximum cooling or maximum heating by continuously flowing air through multiple heat exchangers in the air conditioning case. [Means for solving the problem]

[0009] To solve these problems, the present invention has the following configuration. A vehicle air conditioning system comprising an air conditioning case equipped with multiple heat exchangers, and a heat transfer medium circuit for circulating heated or cooled heat transfer medium through the heat exchangers, wherein the air blown into the air conditioning case and passing through the heat exchangers is heated or cooled, the heat transfer medium circuit flows the heat transfer medium in series or in parallel to a first heat exchanger provided on the upwind side and a second heat exchanger provided on the downwind side within the air conditioning case, the air conditioning case comprises a main airflow channel through which air flows continuously between the first heat exchanger and the second heat exchanger, and a bypass airflow channel through which air that has passed through the first heat exchanger bypasses the second heat exchanger, and the bypass airflow channel is provided with an airflow adjustment damper for adjusting the amount of air blown through the bypass airflow channel. [Effects of the Invention]

[0010] According to the present invention, which has these features, in a vehicle air conditioning system that uses the heat absorption and heat release of a heat pump as a heat source to cool or heat a heat transfer medium such as water or LLC, and circulates this heat transfer medium to various locations for air conditioning and temperature control, the desired airflow volume can be secured without increasing the airflow capacity when performing maximum cooling or maximum heating by having air continuously flow through multiple heat exchangers in the air conditioning case. [Brief explanation of the drawing]

[0011] [Figure 1] An explanatory diagram of a vehicle air conditioning system according to an embodiment of the present invention (at maximum cooling). [Figure 2] An explanatory diagram of a vehicle air conditioning system according to an embodiment of the present invention (at maximum heating). [Figure 3] This diagram illustrates the airflow conditions inside the air conditioning case ((a) is the low-temperature mode during maximum cooling (high-temperature mode during maximum heating), and (b) is the increased airflow mode during maximum cooling (increased airflow mode during maximum heating)). [Figure 4] Diagram illustrating the control device that controls the airflow adjustment damper. [Figure 5] An explanatory diagram showing the core thickness and fin pitch of the first and second heat exchangers inside the air conditioning case. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will now be described with reference to the drawings. In the following description, the same reference numerals in different figures indicate parts with the same function, and redundant explanations in each figure will be omitted as appropriate.

[0013] In Figure 1 or Figure 2, the vehicle air conditioning system 1 includes an air conditioning case 10. The air conditioning case 10 is equipped with a plurality of heat exchangers, and in the illustrated example, a first heat exchanger 11 is located on the windward side and a second heat exchanger 12 is located on the leeward side. An airflow channel is formed in the air conditioning case 10 through which air from inside or outside the vehicle cabin, supplied by a fan (not shown), flows, and the first heat exchanger 11 and the second heat exchanger 12 are arranged to intersect this airflow channel.

[0014] The airflow channels formed in the air conditioning case 10 include a main airflow channel 10A through which air supplied from a fan (not shown) flows continuously to the first heat exchanger 11 on the windward side and the second heat exchanger 12 on the leeward side, and a bypass airflow channel 10B through which air that has passed the first heat exchanger 11 bypasses the second heat exchanger 12. In the illustrated example, the main airflow channel 10A and the bypass airflow channel 10B are separated by a partition 14.

[0015] The bypass airflow channel 10B is equipped with an airflow control damper 13 that adjusts the amount of air flowing through the bypass airflow channel 10B. By closing the airflow control damper 13 completely and blocking the bypass airflow channel 10B, all the air that has passed through the first heat exchanger 11 will pass through the second heat exchanger 12. By opening the airflow control damper 13 and allowing air to flow through the bypass airflow channel 10B, some of the air that has passed through the first heat exchanger 11 will pass through the second heat exchanger 12, and the rest of the air will flow through the bypass airflow channel 10B.

[0016] The air flowing through the main airflow channel 10A, or the combined air from the main airflow channel 10A and the bypass airflow channel 10B, is sent to an appropriate outlet in the air conditioning case 10 (for example, a defroster outlet, a vent outlet, a foot outlet, etc.), which is not shown in the illustration.

[0017] In Figure 1 or Figure 2, the vehicle air conditioning system 1 is equipped with a heat transfer medium circuit 30. The heat transfer medium circuit 30 circulates a heat transfer medium (such as water or LLC) heated or cooled by the heat pump 20, which is the heat source of the heat management system, through multiple heat exchangers (first heat exchanger 11 and second heat exchanger 12) inside the air conditioning case 10. The heat pump 20 is equipped with a compressor 21 that compresses the refrigerant, a radiator (condenser) 22 that condenses the compressed refrigerant, a pressure reducing unit (expansion valve) 23 that reduces the pressure of the condensed refrigerant, and a heat absorber (evaporator) 24 that vaporizes the reduced pressure refrigerant. The heat transfer medium circulating in the heat transfer medium circuit 30 forms two independent circuits: one in which a high-temperature heat transfer medium passes through the radiator 22 and another in which a low-temperature heat transfer medium passes through the heat absorber 24.

[0018] In the illustrated example, the heat transfer fluid circuit 30 includes circulation pumps 31 and 32, as well as a plurality of flow path switching valves (V10 to V16, V20 to V26). By opening or closing any of the flow path switching valves (V10 to V16, V20 to V26), the flow path of the heat transfer fluid circuit 30 can be switched as appropriate (black in the illustration indicates the closed state of the valve, and white indicates the open state of the valve).

[0019] During maximum cooling as shown in FIG. 1, the heat medium circuit 30 flows the low-temperature heat medium that has passed through the heat absorber 24 in series through the first heat exchanger 11 and the second heat exchanger 11 (in the example shown in the figure, the heat medium that has passed through the second heat exchanger 12 flows through the first heat exchanger 11, but the reverse flow is also acceptable), and flows the heat medium that has passed through the radiator 22 into the external heat exchanger 33 to radiate heat to the outside air. Also, during maximum heating as shown in FIG. 2, the heat medium circuit 30 flows the high-temperature heat medium that has passed through the radiator 22 in series through the first heat exchanger 11 and the second heat exchanger 12, and flows the low-temperature heat medium that has passed through the heat absorber 24 into the external heat exchanger 33 to absorb heat from the outside air. In the example shown in the figure, an example of flowing the heat medium in series through the first heat exchanger 11 and the second heat exchanger 12 is shown, but it is not limited to this, and the heat medium may be flowed in parallel through the first heat exchanger 11 and the second heat exchanger 12.

[0020] Note that the heat medium circuit 30 shown in FIGS. 1 and 2 is an example, and the embodiments of the present invention are not particularly limited thereto. Also, the heat medium circuit 30 can be appropriately extended to a circuit for exchanging heat with a temperature-controlled object such as a battery (not shown).

[0021] Such a vehicle air conditioner 1, during maximum cooling, as shown in FIG. 3(a), closes the air volume adjustment damper 13 completely to block the bypass air flow path 10B, so that all the air that has passed through the first heat exchanger 11 flows into the second heat exchanger 12, and the air that has exchanged heat with the low-temperature heat medium is sent into the vehicle interior. Also, during maximum cooling, as shown in FIG. 3(b), the vehicle air conditioner 1 partially opens the bypass air flow path 10B by the air volume adjustment damper 13, so that a part of the air that has passed through the first heat exchanger 11 flows into the second heat exchanger 12, and the other air that has passed through the first heat exchanger 11 flows into the bypass air flow path 10B.

[0022] [[ID=II]] In this case, as shown in Figure 3(a), when the airflow control damper 13 is fully closed and the bypass airflow channel 10B is blocked, the airflow resistance of the air flowing continuously through the first heat exchanger 11 and the second heat exchanger 12 increases, and the overall airflow rate decreases. However, by passing through the first heat exchanger 11 and the second heat exchanger 12 continuously, air that has been sufficiently cooled in two stages can be obtained. Also, as shown in Figure 3(b), by opening the airflow control damper 13 and allowing air to flow through the bypass airflow channel 10B, the airflow resistance decreases, making it possible to increase the airflow rate during maximum cooling. In this case, since some of the air passes through the second heat exchanger 12, the temperature of the air can be lowered compared to using only one heat exchanger (evaporator) as in conventional HVAC systems. The degree to which the airflow control damper 13 is opened may be controlled, for example, by the degree of the discharge temperature.

[0023] Furthermore, the explanations in Figures 3(a) and 3(b) can also be applied to maximum heating when a high-temperature heat transfer medium is flowed through the first heat exchanger 11 and the second heat exchanger 12. That is, during maximum heating, as shown in Figure 3(a), when the airflow adjustment damper 13 is fully closed and the bypass airflow channel 10B is blocked, air passes continuously through the first heat exchanger 11 and the second heat exchanger 12, allowing air to be heated to a sufficiently high temperature in two stages. Also, as shown in Figure 3(b), by flowing air through the bypass airflow channel 10B, the airflow resistance is reduced, making it possible to increase the airflow rate during maximum heating.

[0024] The switching of the airflow adjustment damper 13 shown in Figures 3(a) and 3(b) can be performed by the control device 40 shown in Figure 4. For example, based on the switching operation input, the control device 40 switches the vehicle air conditioning system 1 from normal operation to maximum cooling (or heating) operation, and further switches between low temperature (high temperature) mode and increased airflow mode during maximum cooling (or heating) operation.

[0025] The low-temperature (high-temperature) mode here is an operating mode used when you want to improve comfort by lowering (raising) the temperature of the air blown into the cabin. In this operating mode, as shown in Figure 3(a), the airflow adjustment damper 13 is controlled to fully close or reduce its opening, thereby sending cooler (higher) air into the cabin.

[0026] Furthermore, the increased airflow mode is an operating mode used when it is desired to increase airflow to improve comfort even during maximum cooling (or maximum heating). In this operating mode, as shown in Figure 3(b), the airflow adjustment damper 13 is controlled to fully open or increase its opening degree, adding air flowing from the first heat exchanger 11 through the bypass airflow channel 10B to the air flowing continuously through the first heat exchanger 11 and the second heat exchanger 12, thereby increasing the airflow during maximum cooling (or maximum heating).

[0027] The control unit 40 can be configured as a single ECU connected via an in-vehicle network to various ECUs (Electronic Control Units) that control the vehicle. The control unit 40 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input / output I / F (Interface), in-vehicle communication I / F (Interface), etc., and each piece of hardware is interconnected via a bus.

[0028] The first heat exchanger 11 and the second heat exchanger 12, which are installed in the air conditioning case 10 of such a vehicle air conditioning system 1, can have their airflow performance and other aspects improved by appropriately setting the core thickness (thickness of the part through which air passes) and the fin pitch of the heat exchange fins along the direction of airflow.

[0029] Specifically, firstly, in Figure 5, it is preferable that the core thickness T1 of the first heat exchanger 11 and the core thickness T2 of the second heat exchanger 12 are equal (T1=T2), and it is also preferable that the fin pitch P1 of the first heat exchanger 11 and the fin pitch P2 of the second heat exchanger 12 are equal (P1=P2) (wherein the fin pitch refers to the distance between the peaks of the corrugated fins). By standardizing the specifications of the tubes and heat exchange fins in the first heat exchanger 11 and the second heat exchanger 12, which have equal core thickness and fin pitch, cost reduction becomes possible.

[0030] It is preferable that the core thickness T1 of the first heat exchanger 11 and the core thickness T2 of the second heat exchanger 12 are both 30 mm or less. In conventional vehicle air conditioning systems, the core thickness of the evaporator is about 40 mm, and the core thickness of the heater core is about 25 to 30 mm. By setting the core thickness T1 of the first heat exchanger 11 and the core thickness T2 of the second heat exchanger 12 to both 30 mm or less, the total core thickness of the two heat exchangers can be reduced compared to conventional technology. As a result, the airflow resistance can be reduced compared to conventional systems when heating operation is performed in which air passes through both the evaporator and the heater core.

[0031] Furthermore, the fin pitch P1 of the first heat exchanger 11 and the fin pitch P2 of the second heat exchanger 12 are preferably 2.4 to 3 mm. In the prior art, the fin pitch of an evaporator is about 2.4 to 3 mm, and the fin pitch of a heater core is about 1.5 to 2 mm. However, in the embodiment of the present invention, the second heat exchanger 12 is used as a cooler during maximum cooling, so it is preferable to keep the fin pitch the same as that of a conventional evaporator from the viewpoint of draining condensate and avoiding water splashing.

[0032] According to this vehicle air conditioning system 1, a heat management system that cools or heats a heat medium by the heat absorption and heat release of a heat pump 20 which serves as a heat source, and circulates this heat medium to various locations to perform air conditioning and temperature control in various locations, ensures that the desired airflow volume can be secured without increasing the blower's airflow capacity when performing maximum cooling or maximum heating by having air continuously flow through multiple heat exchangers in the air conditioning case 10. As a result, comfortable air conditioning can be performed with the desired airflow volume at maximum cooling or maximum heating without increasing blower drive power or airflow noise.

[0033] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and any design changes, etc., that do not depart from the gist of the present invention are also included. Furthermore, the above-described embodiments can be combined by utilizing each other's technologies, as long as there are no particular contradictions or problems in their purpose and configuration. [Explanation of Symbols]

[0034] 1: Vehicle air conditioning system, 10: Air conditioning case, 10A: Main airflow channel, 10B: Bypass airflow channel, 11: First heat exchanger, 12: Second heat exchanger, 13: Airflow control damper, 14: Partition section, 20: Heat pump, 21: Compressor, 22: Heat sink, 23: Pressure reducing section, 24: Heat absorber, 30: Heat transfer fluid circuit, 31, 32: Circulation pump, V10~V16, V20~V26: Flow path switching valve, 33: External heat exchanger, 40: Control device, F: Heat exchange fin, P1, P2: Fin pitch, T1, T2: Core thickness

Claims

1. A vehicle air conditioning system comprising an air conditioning case equipped with multiple heat exchangers, a heat transfer medium circuit that circulates heated or cooled heat transfer medium through the heat exchangers, and heating or cooling the air that is blown into the air conditioning case and passes through the heat exchangers, The heat transfer medium circuit flows the heat transfer medium in series or in parallel between a first heat exchanger located on the upwind side and a second heat exchanger located on the downwind side within the air conditioning case. The air conditioning case includes a main airflow channel through which air flows continuously between the first heat exchanger and the second heat exchanger, and a bypass airflow channel through which air that has passed through the first heat exchanger flows, bypassing the second heat exchanger. The bypass airflow channel is provided with an airflow control damper to adjust the amount of air blown through the bypass airflow channel. The airflow adjustment damper is characterized by flowing air through the bypass airflow channel when a low-temperature heat transfer medium is flowed through the first heat exchanger and the second heat exchanger during maximum cooling, or when a high-temperature heat transfer medium is flowed through the first heat exchanger and the second heat exchanger during maximum heating.

2. The vehicle air conditioning system according to claim 1, characterized in that the first heat exchanger and the second heat exchanger have equal core thicknesses along the direction of airflow.

3. The vehicle air conditioning system according to claim 1 or 2, characterized in that the core thickness of the first heat exchanger and the second heat exchanger along the airflow direction is 30 mm or less.

4. The vehicle air conditioning system according to any one of claims 1 to 3, characterized in that the fin pitch of the heat exchange fins of the first heat exchanger and the second heat exchanger are equal.

5. The vehicle air conditioning system according to any one of claims 1 to 4, characterized in that the first heat exchanger and the second heat exchanger have a fin pitch of 2.4 to 3 mm, which is the distance between the peaks of the heat exchange fins.

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