Vehicle air conditioning system

Abstract

The present invention provides a vehicle air conditioning system that can provide low-cost air conditioning in the vehicle cabin while suppressing heat energy loss in a vehicle using a heat pump type refrigerant circuit. [Solution] The vehicle air conditioning system 1 is a vehicle air conditioning system that uses a heat pump type refrigerant circuit to air condition the inside of the vehicle, and comprises: an outdoor heat exchanger 501 provided in the refrigerant circuit 500 and performing heat exchange between the refrigerant circulating in the refrigerant circuit 500 and the outside air; a compressor 503 provided in the refrigerant circuit 501 and compressing the refrigerant that has passed through the outdoor heat exchanger 501; a condenser 102 provided in the refrigerant circuit 500 and dissipating heat from the refrigerant that has passed through the compressor 503; and an exhaust duct 300 that exhausts the air inside the vehicle, which has been heated using the heat dissipated from the condenser 102, toward the outdoor heat exchanger 501.

Description

Technical Field

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

Background Art

[0002] The air conditioning system of an engine vehicle performs air conditioning in the vehicle interior by using the exhaust heat of the engine. On the other hand, the air conditioning system of an electric vehicle without an engine generally performs air conditioning in the vehicle interior using a refrigerant circuit of a heat pump system.

[0003] For example, in Patent Document 1, when the vehicle air conditioner operates in the heating mode, after the refrigerant is compressed to a high temperature and high pressure by the compressor, it is sent to the indoor heat exchanger in sequence through the four-way valve and the refrigerant pipe. This high-temperature and high-pressure refrigerant is liquefied by heat exchange in the indoor heat exchanger, and the liquefied refrigerant is sent to the expansion valve through the refrigerant pipe. The expansion valve expands it rapidly to a low temperature and low pressure, and this low-temperature refrigerant is sent to the outdoor heat exchanger and vaporized by heat exchange, and the gaseous refrigerant is returned to the compressor through the four-way valve.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the technology described in Patent Document 1 is used for vehicle heating, when the outside air temperature is low, the heat absorption efficiency (heat exchange efficiency) of the refrigerant in the outdoor heat exchanger becomes low, so the refrigerant must be heated by a PTC (Positive Temperature Coefficient) heater or the like, which requires high costs.

[0006] Furthermore, when using the vehicle's heating system, it is preferable to ventilate the interior to prevent the windows from fogging up. However, ventilation causes heat to escape from the interior to the outside, resulting in a loss of thermal energy.

[0007] Therefore, the object of the present invention is to provide a vehicle air conditioning system that can provide low-cost air conditioning in the vehicle cabin while suppressing the loss of thermal energy in a vehicle using a heat pump type refrigerant circuit. [Means for solving the problem]

[0008] The present invention has been made to solve at least some of the aforementioned problems and can be realized in the following embodiments or application examples.

[0009] The vehicle air conditioning system according to this application example is a vehicle air conditioning system that uses a heat pump type refrigerant circuit to air condition the interior of a vehicle, and comprises: an outdoor heat exchanger provided in the refrigerant circuit and performing heat exchange between the refrigerant circulating in the refrigerant circuit and the outside air; a compressor provided in the refrigerant circuit and compressing the refrigerant that has passed through the outdoor heat exchanger; a condenser provided in the refrigerant circuit and dissipating heat from the refrigerant that has passed through the compressor; and an exhaust duct that exhausts the air in the interior of the vehicle, which has been heated using the heat dissipated from the condenser, toward the outdoor heat exchanger.

[0010] According to this application example, since an exhaust duct is provided to exhaust heated cabin air towards the outdoor heat exchanger, when ventilating the cabin, heated cabin air can be exhausted towards the outdoor heat exchanger. This raises the temperature of the air near the outdoor heat exchanger, increasing the heat absorption efficiency (heat exchange efficiency) of the refrigerant in the outdoor heat exchanger. Therefore, even when the outside temperature is low, the heat absorption efficiency (heat exchange efficiency) of the refrigerant in the outdoor heat exchanger can be maintained at a high level. In this way, by effectively utilizing the thermal energy contained in the heated cabin air, it is possible to suppress situations where heating means such as PTC (Positive Temperature Coefficient) heaters must be used when heating the vehicle.

[0011] Therefore, according to this application example, it is possible to provide a vehicle air conditioning system that can perform air conditioning inside the vehicle at low cost while suppressing the loss of thermal energy in a vehicle using a heat pump type refrigerant circuit. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic side view of a truck to which one embodiment of the vehicle air conditioning system according to the present invention is applied. [Figure 2] This is an overall configuration diagram showing one embodiment of the vehicle air conditioning system according to the present invention. [Modes for carrying out the invention]

[0013] Next, an embodiment of the vehicle air conditioning system according to the present invention will be described with appropriate reference to Figures 1 and 2.

[0014] The air conditioning system 1 shown in Figures 1 and 2 is an embodiment of the vehicle air conditioning system according to the present invention, and is installed from inside the vehicle to outside (near the vehicle) of an electric vehicle, a truck 1000. As shown in Figure 2, the air conditioning system 1 includes a first refrigerant circuit 100 for interior heating, an interior fan 200 for interior heating and cooling, an exhaust duct 300 for interior ventilation, an exterior fan 400 for interior heating and cooling, a second refrigerant circuit 500 for interior heating and cooling, and a third refrigerant circuit 600 for temperature control of the battery B. The battery B is for storing electricity for the truck 1000 to run.

[0015] The first refrigerant circuit 100 is a heater circuit for circulating the first refrigerant to heat the heater core 104. The first refrigerant circuit 100 is connected to the first pump 101, the condenser 102, the heater 103, and the heater core 104, each via a flow path through which the first refrigerant passes. The first refrigerant is a liquid refrigerant, such as water or glycol.

[0016] The first pump 101 is an electric pump for circulating the first refrigerant in the first refrigerant circuit 100. The condenser 102 is a condenser that causes the first refrigerant to absorb heat by exchanging heat with the second refrigerant (described later), and heats the first refrigerant with the heated second refrigerant. The heater 103 is a PTC (Positive Temperature Coefficient) heater for heating the first refrigerant as needed. The heater core 104 is an indoor heat exchanger that exchanges heat between the first refrigerant heated by the condenser 102 or heater 103 and the indoor air (air inside the cabin of the truck 1000). As shown in Figure 1, the heater core 104 is installed in an air conditioning duct D formed in the inner panel at the front of the cab of the truck 1000.

[0017] The interior fan 200 is also installed in the air conditioning duct D located within the inner panel at the front of the cab of the truck 1000, as shown in Figure 1. As shown in Figures 1 and 2, it is used to ventilate the interior of the vehicle by drawing in outside air. Although not shown in Figure 1, an evaporator 505 is also installed in the air conditioning duct D.

[0018] As shown in Figures 1 and 2, the exhaust duct 300 constitutes an air passage that connects the interior and exterior of the truck 1000, and is intended to discharge the air inside the truck 1000's interior toward the outdoor heat exchanger 501 outside the vehicle. One end of the exhaust duct 300 is connected to the interior of the truck 1000, and the other end of the exhaust duct 300 is located near the outdoor heat exchanger 501 outside the vehicle.

[0019] The outdoor fan 400 is used to draw in exhaust air from the exhaust duct 300 along with outside air, and to supply this mixture of exhaust air and outside air to the outdoor heat exchanger 501.

[0020] The second refrigerant circuit 500 is a heat pump circuit in which the second refrigerant circulates and heat exchange occurs between the first refrigerant and the third refrigerant (details of which will be described later). The second refrigerant circuit 500 has three flow paths: a first route R1 used for indoor heating, a second route R2 used for indoor cooling, and a third route R3 used for cooling battery B. The second refrigerant is, for example, carbon dioxide or HFO-1234yf.

[0021] The second refrigerant circuit 500 includes, in the first route R1, an outdoor heat exchanger 501, an accumulator 502, a compressor 503, a condenser 102, and a heating expansion valve 504.

[0022] The outdoor heat exchanger 501 is a heat exchanger that exchanges heat between the second refrigerant and the mixed air of the exhaust from the exhaust duct 300 and the outside air. This mixed air is supplied to the outdoor heat exchanger 501, for example, by suction by the outdoor fan 400, air flow due to the running of the truck 1000, air pressure in the cab of the truck 1000, and the like. And the outdoor heat exchanger 501 absorbs heat from the mixed air to the second refrigerant during indoor heating, and releases heat from the second refrigerant to the outside air during indoor cooling. The accumulator 502 is a gas-liquid separation device that separates the gas and liquid of the second refrigerant. The compressor 503 is a compressor that compresses the second refrigerant to increase its pressure and temperature. The condenser 102 dissipates heat from the second refrigerant by exchanging heat between the second refrigerant and the first refrigerant. The heating expansion valve 504 is a valve that reduces the pressure and temperature of the high-pressure second refrigerant.

[0023] Also, the second refrigerant circuit 500 includes an evaporator 505 in the second route R2 and a chiller 506 in the third route R3. Both the second route R2 and the third route R3 are connected between the outdoor heat exchanger 501 and the accumulator 502.

[0024] The second refrigerant circuit 500 is provided with a first switching valve 507 for switching the flow paths of each route, a cooling expansion valve 508, and a chiller expansion valve 509. Each switching valve is electrically connected to an ECU (Electronic Control Unit) mounted on the truck 1000 (not shown) and is controlled to open and close by the ECU.

[0025] Specifically, the first switching valve 507 is provided between the outdoor heat exchanger 501 and the accumulator 502, the cooling expansion valve 508 is provided between the outdoor heat exchanger 501 and the evaporator 505, and the chiller expansion valve 509 is provided between the outdoor heat exchanger 501 and the chiller 506.

[0026] During heating, the first switching valve 507 is opened and the cooling expansion valve 508 and the chiller expansion valve 509 are closed, allowing the second refrigerant to circulate through the first route R1. During cooling, the first switching valve 507 is closed and the cooling expansion valve 508 is opened, allowing the second refrigerant to circulate through the second route R2 in addition to the first route R1, and the indoor air is cooled by the evaporator 505. When the chiller 506 is used, the first switching valve 507 is closed and the chiller expansion valve 509 is opened, allowing the second refrigerant to circulate through the third route R3 in addition to the first route R1, and heat exchange takes place between the second refrigerant and the third refrigerant in the third refrigerant circuit 600 in the chiller 506.

[0027] The third refrigerant circuit 600 is a battery cooling circuit that circulates the third refrigerant to regulate (cool and warm up) the temperature of battery B. The third refrigerant circuit 600 is connected to the third pump 601, the chiller 506, and a heater (not shown in the diagram) via a flow path through which the third refrigerant passes. The third refrigerant is a liquid refrigerant, such as water or glycol.

[0028] The third pump 601 is an electric pump for circulating the third refrigerant in the third refrigerant circuit 600. The chiller 506 is a heat exchanger for heat exchange between the third refrigerant and the second refrigerant, and is mainly used to cool the third refrigerant with the lower temperature second refrigerant. The third refrigerant in the third refrigerant circuit 600 may be heated by a heater (not shown) in the third refrigerant circuit 600 when it is necessary to heat battery B.

[0029] Next, we will explain the operation of air conditioning system 1 during heating. Since the operation during cooling is known, we will omit the explanation.

[0030] First, in the second refrigerant circuit 500, the second refrigerant circulates through the first route R1. Specifically, the second refrigerant absorbs heat from the outside air in the outdoor heat exchanger 501, is separated into gas and liquid in the accumulator 502, and is then compressed by the compressor 503 to increase its pressure and temperature, which in turn heats the first refrigerant in the first refrigerant circuit 100 in the condenser 102. After passing through the condenser 102, the second refrigerant rapidly expands in the heating expansion valve 504, decreasing its pressure and temperature, and then absorbs heat again in the outdoor heat exchanger 501. Then, in the first refrigerant circuit 100, the first refrigerant heated in the condenser 102 heats the indoor air in the heater core 104 to heat the room.

[0031] Furthermore, by drawing outside air into the vehicle cabin through the indoor fan 200 and the airflow caused by the movement of the truck 1000, the interior air from the vehicle cabin is supplied to the inside of the exhaust duct 300 from one end of the exhaust duct 300, and this interior air is exhausted from the other end of the exhaust duct 300 toward the outdoor heat exchanger 501. The mixed air, including the exhaust from the other end of the exhaust duct 300 and the outside air, is then supplied to the outdoor heat exchanger 501 by the suction from the outdoor fan 400, the airflow caused by the movement of the truck 1000, and the air pressure inside the vehicle cabin of the truck 1000. From this point onward, the second refrigerant circulating in the second refrigerant circuit 500 absorbs heat from this mixed air in the outdoor heat exchanger 501.

[0032] According to the air conditioning system 1 of this embodiment, since it is equipped with an exhaust duct 300 that exhausts the heated air inside the vehicle interior toward the outdoor heat exchanger 501, when ventilating the vehicle interior, the heated air inside the vehicle interior can be exhausted toward the outdoor heat exchanger 501. This raises the temperature of the air near the outdoor heat exchanger 501, and increases the heat absorption efficiency (heat exchange efficiency) of the second refrigerant in the outdoor heat exchanger 501. Therefore, even when the outside temperature is low, the heat absorption efficiency (heat exchange efficiency) of the second refrigerant in the outdoor heat exchanger 501 can be maintained at a high level. In this way, by effectively utilizing the thermal energy contained in the heated air inside the vehicle interior, it is possible to suppress situations where heating means such as PTC heaters must be used when heating the vehicle.

[0033] Therefore, in a vehicle (truck 1000) using a heat pump type refrigerant circuit, it is possible to provide a vehicle air conditioning system 1 that can perform air conditioning inside the vehicle at low cost while suppressing the loss of thermal energy.

[0034] This concludes the description of embodiments of the present invention, but the embodiments of the present invention are not limited to these embodiments. For example, the air conditioning system 1 shown in Figure 2 is applicable to any vehicle that uses a heat pump type refrigerant circuit to provide air conditioning in the vehicle interior, and can be applied to engine vehicles, electric vehicles, and hybrid vehicles, as well as to regular cars, medium-sized cars, and large cars.

[0035] Furthermore, in this embodiment, the air conditioning system 1 is equipped with a first refrigerant circuit 100, and heating is performed using the heat radiated from the condenser 102 via the first refrigerant circuit 100. However, in the present invention, the installation of the first refrigerant circuit 100 may be omitted, and the condenser 102 may be placed inside the air conditioning duct D and used as a heater core (corresponding to the heater core 104 in this embodiment). [Explanation of Symbols]

[0036] 1. Vehicle air conditioning system 100 1st refrigerant circuit 101 Pump No. 1 102 Capacitors 103 Heater 200 Indoor Fan 300 Exhaust Duct 400 Outdoor Fan 500 2nd refrigerant circuit 501 Outdoor heat exchanger 502 Accumulator 503 Compressor 504 Heating Expansion Valve 505 Evaporator 506 Chiller 507 First changeover valve 508 Expansion valve for air conditioning 509 Chiller Expansion Valve 600 Third refrigerant circuit 601 Third Pump 1000 trucks B Battery D Air conditioning duct R1 Route 1 Route R2, Route 2 Route 3, Third Route

Claims

[Claim 1] A vehicle air conditioning system that uses a heat pump type refrigerant circuit to provide air conditioning for the vehicle interior, An outdoor heat exchanger is provided in the refrigerant circuit and performs heat exchange between the refrigerant circulating in the refrigerant circuit and the outside air. A compressor is provided in the refrigerant circuit and compresses the refrigerant that has passed through the outdoor heat exchanger, A capacitor is provided in the refrigerant circuit to dissipate heat from the refrigerant that has passed through the compressor, An exhaust duct that exhausts the air inside the vehicle, which has been heated using the heat dissipated from the condenser, toward the outdoor heat exchanger, A vehicle air conditioning system equipped with the following features.

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