JP2013126858A - Arrangement structure of vehicle heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arrangement structure of a vehicle heat exchanger in which a low-water-temperature radiator for cooling electronic equipment such as an inverter is arranged upstream of a flowing direction of cooling air.SOLUTION: The arrangement structure of the vehicle heat exchanger includes: an outdoor heat exchanger (3) of a heat pump system of the vehicle air conditioner; and the low-water temperature radiator (12) for cooling a low-temperature heating element (11) including an inverter for a vehicle traveling motor in which the low-water temperature radiator (12) is arranged upstream of a flowing direction of cooling air relative to the outdoor heat exchanger (3).

Description

  The present invention relates to a cooling air flow for a condenser (hereinafter referred to as an outdoor heat exchanger) of a heat pump system of an air conditioner in a hybrid vehicle (HEV), an electric vehicle (EV), a plug-in hybrid vehicle (PHEV), and the like. The present invention relates to an arrangement structure of a heat exchanger for a vehicle in which a low water temperature radiator for cooling an electronic device such as an inverter is arranged upstream in the direction.

  As seen in Patent Document 1, a hybrid vehicle (HEV, PHEV) is provided with two drive sources, an engine and a travel motor, and converts the direct current of the on-board secondary battery into alternating current. An inverter that supplies the motor for travel is installed. In such a hybrid vehicle, in addition to cooling the engine, it is necessary to cool the driving motor and inverter of the hybrid system. Therefore, the hybrid vehicle is provided with two cooling circuits, that is, a cooling circuit for cooling the engine (engine cooling circuit) and a cooling circuit for the hybrid system (hybrid cooling circuit), and the cooling water is circulated through each cooling circuit. The engine and the hybrid system are cooled by this.

  The appropriate cooling water temperature differs between the engine cooling circuit and the hybrid cooling circuit. Also, the maximum allowable cooling water temperature varies between cooling circuits. For example, the cooling water in the engine cooling circuit (engine cooling water) may exceed 100 ° C. depending on the operating state of the engine, but the cooling water in the hybrid cooling circuit (hybrid cooling water) has a significantly lower temperature ( For example, it is necessary to keep it at 65 ° C. or lower. Therefore, in a hybrid vehicle, it is common to provide an engine cooling circuit and a hybrid cooling circuit.

  FIG. 1 is an explanatory view showing an arrangement structure of a conventional general vehicle heat exchanger. In a hybrid vehicle (HEV, PHEV) or the like, a low water temperature radiator 12 for cooling an electronic device such as an inverter and a high water temperature radiator 2 for cooling the engine 1 are provided for an outdoor heat exchanger 3 of a heat pump system of an air conditioner. In this order, they are arranged on the downstream side of the cooling air flow (in the case of an electric vehicle (EV), there is no high water temperature radiator 2 drawn by an imaginary line in FIG. 1). Moreover, in patent document 2, although the low water temperature radiator 12 for cooling electronic devices, such as an inverter, is provided integrally with the high water temperature radiator 2, similarly to the arrangement structure of the conventional vehicle heat exchanger, The low water temperature radiator 12 is disposed downstream of the cooling air flow with respect to the outdoor heat exchanger 3 of the air conditioner.

  In recent years, in hybrid vehicles (HEV), plug-in hybrid vehicles (PHEV), electric vehicles (EV), etc., there is an increasing demand for extending the mileage as much as possible, and a heat pump system with excellent COP (coefficient of performance) during heating. The adoption of is expected to increase in the future. When the heat pump system is employed in the arrangement structure of the vehicle heat exchanger as described above, there is a problem that the heating capacity at a low outside air temperature is insufficient and the capacity is reduced even at the time of frost formation.

JP 2011-98628 A JP 2001-59420 A

  In view of the above problems, the present invention is a vehicle heat exchange in which a low water temperature radiator for cooling an electronic device such as an inverter is arranged upstream of an outdoor heat exchanger of a heat pump system of an air conditioner in an air flow direction for cooling. The arrangement structure of the vessel is provided.

  In order to solve the above-mentioned problems, the invention of claim 1 is a low-temperature cooling element (11) including an outdoor heat exchanger (3) of a heat pump system of a vehicle air conditioner and an inverter for a vehicle travel motor. A vehicle heat exchanger arrangement structure comprising a water temperature radiator (12), wherein the low water temperature radiator (12) is disposed upstream of the outdoor heat exchanger (3) in a cooling air flow direction. It is the arrangement structure of the heat exchanger for vehicles which has arranged.

  As a result, during heating, the temperature of the cooling water flowing through the low water temperature radiator increases the outside air temperature, increasing the temperature of the air passing through the outdoor heat exchanger of the heat pump system, and improving the capacity of the heat pump system , Frost formation can be prevented. Moreover, even if it forms frost, an inner side outdoor heat exchanger can be protected from frosting as much as possible by making it frost on the low water temperature radiator of the upstream of an outdoor heat exchanger. On the other hand, if the layout is such that a low water temperature radiator is installed on the upstream side even during cooling, the influence on cooling performance can be minimized. Furthermore, since the temperature of the cooling air flowing into the low water temperature radiator can prevent an increase in the temperature of the passing air for cooling by the outdoor heat exchanger 3 during the cooling operation, the cooling capacity can be reduced as compared with the conventional one. Miniaturization is possible and a space-saving effect is also obtained.

  In addition, the code | symbol attached | subjected above is an example which shows a corresponding relationship with the specific embodiment as described in embodiment mentioned later.

It is explanatory drawing which shows the arrangement structure of the conventional vehicle heat exchanger. It is explanatory drawing as an example of one Embodiment of this invention. It is a flowchart explaining the moisture blowing off function at the time of defrosting. It is explanatory drawing at the time of inclining the outdoor heat exchanger of other embodiment of this invention. It is explanatory drawing of the outdoor heat exchanger with which the water | moisture content of other embodiment of this invention tends to drip.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. About each embodiment, the same code | symbol is attached | subjected to the part of the same structure, and the description is abbreviate | omitted.

  FIG. 2 is an explanatory diagram as an example of an embodiment of the present invention. The present embodiment is an example of the entire system when applied to a hybrid vehicle (HEV, PHEV). In the case of an electric vehicle (EV), a fuel cell vehicle, etc., the high water temperature radiator 2 of FIG. 2 does not exist. One embodiment of the present invention is not necessarily limited to the case of FIG. 2, and may be applied to other heat pump type air conditioners.

  Reference numeral 20 denotes an air conditioner indoor unit (HVAC), and an indoor fan is disposed on one end side thereof. This indoor blower has a centrifugal blower fan 8 and a drive motor 8 ', and the blower fan 8 sucks air from the suction port of the blower fan and blows air. The air sucked from the suction port may be switchable between inside air and outside air by an inside / outside air switching door. There are many modified examples of the air conditioner indoor unit 20, and the present invention is not necessarily limited to the embodiment of FIG.

  Reference numeral 5 denotes an indoor evaporator (evaporator) disposed on the downstream side of the blower fan 8 to cool the blown air by exchanging heat between the low-pressure refrigerant of the refrigeration cycle and the blown air. Reference numeral 4 denotes an indoor heat exchanger (condenser) disposed on the downstream side of the indoor evaporator 5 in the air conditioner indoor unit section 20, and heat is generated between the high-pressure refrigerant discharged from the electric compressor 21 of the refrigeration cycle and the blown air. Replace and heat the blown air. In the heat pump type air conditioner (heat pump system) of the present embodiment, the indoor evaporator 5 and the indoor heat exchanger 4 are used as the indoor heat exchanger.

  The passage switching door 9 (air mix door) is between the dotted line and the solid line in FIG. 2 and the air flow rate flowing through the indoor heat exchanger 4 and the air flow rate ratio of the bypass passage 4 ′ through which the blown air flows. Are appropriately switched and controlled by a command from the air conditioning control device. Downstream of these, a plurality of air outlets (a face air outlet, a foot air outlet, and a defroster air outlet), which are air outlets into the vehicle compartment, are opened and closed by each air outlet mode door.

  The outdoor heat exchanger 3 performs heat exchange between the refrigerant and the outdoor air. Cooling water (engine cooling water) of the engine cooling circuit is cooled by the high-temperature side radiator 2, and is disposed downstream of the outdoor heat exchanger 3 with respect to the cooling air flow direction (vehicle traveling wind flow direction). Has been. Moreover, the low water temperature radiator for cooling electronic devices such as an inverter is disposed upstream of the outdoor heat exchanger 3 with respect to the cooling air flow direction (vehicle traveling wind flow direction). A suction-type outdoor fan 6 is arranged further downstream of the high-temperature side radiator 2, and the outdoor fan 6 is rotationally driven by a driving motor, whereby the low-temperature side radiator 12, the outdoor heat exchanger 3, and the high-temperature side Air outside the vehicle is blown to the radiator 2 in the cooling air flow direction.

  A cooling circuit for cooling the engine or the like that is cooled by the high-temperature side radiator 2 is formed on the high-temperature heating element 1 such as the engine. In addition, a cooling circuit for a hybrid system or the like that is cooled by the low water temperature radiator 12 is formed independently of the low-temperature heating element 11 such as an inverter. A cooling water circulation pump P is inserted in these cooling circuits. In the case of an electric vehicle (EV), a fuel cell vehicle, etc., there is no cooling circuit (high water temperature radiator 2) for cooling the engine or the like. As this embodiment, the case where the high water temperature radiator 2 does not exist is included as an embodiment.

The refrigerant circuit of the outdoor heat exchanger 3 is switched by a three-way valve 22 and the refrigerant circuit is connected to the refrigerant inlet of the indoor evaporator 5 via a cooling expansion valve 26 (cooling throttle) in the case of cooling. The
In the case of heating, the refrigerant passes through the accumulator 24, the electric compressor 21, the indoor heat exchanger 4, the heating expansion valve 25 (heating restriction) in this order, and returns to the refrigerant inlet of the outdoor heat exchanger 3. A PTC heater 7 is provided downstream of the indoor heat exchanger 4. The PTC heater 7 is an auxiliary heater for auxiliary heating that has a PTC element (positive characteristic thermistor), generates heat when electric power is supplied to the element, and heats air after passing through the indoor heat exchanger 4.

As for the electromagnetic valve 23, the electromagnetic valve 23 is closed when heating, and the electromagnetic valve 23 is opened when cooling. If the electromagnetic valve 23 is opened in the case of cooling, the refrigerant flows through the flow path on the side where the electromagnetic valve 23 is present because of the heating throttle 25.
An accumulator 24 is arranged on the suction side of the electric compressor 21 and stores surplus refrigerant circulating in the cycle, and separates the refrigerant flowing into the gas phase refrigerant and liquid phase refrigerant to convert the gas phase refrigerant into the electric compressor. 21 inhale.

  In the present embodiment, unlike the prior art, the low water temperature radiator 12 for cooling an electronic device such as an inverter is disposed upstream of the outdoor heat exchanger 3 in the cooling air flow direction (vehicle traveling wind flow direction). Has been. The cooling water that has flowed through the low water temperature radiator 12 cools the low-temperature heating element 11 such as an electronic device such as an inverter or a traveling motor.

  In the heat pump system, there has been a known problem that the heating capacity at the low outside temperature is insufficient during the heating operation, and the capacity is reduced even at the time of frost formation. According to the conventional technical common knowledge, in a heat pump system, a radiator may be disposed upstream of the outdoor heat exchanger 3 in the cooling air flow direction in fear of deterioration in cooling performance during cooling. I didn't get it. However, in the layout in which the high-temperature radiator 2 is installed on the upstream side, there is an adverse effect that the cooling performance is greatly deteriorated. However, in the layout in which the low water temperature radiator 12 is installed on the upstream side, the influence on the cooling performance is minimal. I focused on being able to suppress it. In the present embodiment, the low water temperature radiator 12 is intentionally arranged on the upstream side in the cooling air flow direction with respect to the outdoor heat exchanger 3.

  If the low water temperature radiator 12 is disposed upstream of the outdoor heat exchanger 3 in the cooling air flow direction, the cooling air temperature flowing into the low water temperature radiator 12 is caused by the outdoor heat exchanger 3 during cooling operation. Since the cooling air temperature can be prevented from rising, the cooling capacity can be reduced as compared with the conventional case, the size can be reduced, and the space saving effect can be obtained.

In this way, during heating operation, the outside air temperature rises due to the temperature of the cooling water flowing through the low water temperature radiator 12, and the temperature rise of the air passing through the outdoor heat exchanger 3 of the heat pump system is obtained. Ability improves.
If the outdoor heat exchanger 3 of the heat pump system is frosted during the heating operation when the outside air condition is high humidity, heat from the outside cannot be taken in and the heating performance deteriorates. However, in this embodiment, frost formation can be prevented by the temperature of the cooling water flowing through the low water temperature radiator 12. Moreover, even if it forms frost, the inner side outdoor heat exchanger 3 can be protected from frost formation as much as possible by making the low water temperature radiator 12 of the upstream of the outdoor heat exchanger 3 frost.

As another embodiment of the present invention, a function of blowing off moisture at the time of defrosting may be added.
FIG. 3 is a flowchart for explaining the function of blowing water during defrosting.
In order to remove the frost adhering to the outdoor heat exchanger 3, a defrosting operation is performed. During the defrosting operation, the indoor heat exchanger 4 is covered with the passage switching door 9 of the air conditioner indoor unit 20 to stop ventilation. At this time, the hot valve is passed through the outdoor heat exchanger 3 by opening the electromagnetic valve (open / close valve) 23 so as to bypass the heating throttle 25. Others are the same as the circuit configuration at the time of heating, and after returning from the outdoor heat exchanger 3, return to the electric compressor 21 from the accumulator 24 through the three-way valve 22. The outdoor heat exchanger 3 is provided with a frost sensor that is a temperature sensor such as a thermistor, and the frost sensor detects whether or not the temperature is equal to or lower than a predetermined temperature (for example, −1 ° C.).

  With reference to FIG. 3, the moisture blowing function at the time of defrosting is demonstrated. In step 1, frost formation is determined by a frost sensor. In this case, the determination may be made not only by determining whether the temperature is equal to or lower than the predetermined temperature, but also by taking into account the duration time not higher than the predetermined temperature. If it is determined in step 1 that the frost is not formed (NO), the process goes to step 2 and the heating operation is performed. If YES, in step 3, the defrosting operation is started for a predetermined time. In step 4, the defrosting operation is terminated, and in step 5, the water blowing operation is started. This moisture blow-off operation means that the electric fan 6 is turned on / off within a predetermined time by Max voltage (not Max, but may be considerably high voltage) a plurality of times (up to about 2, 3 to 7, 8 times). Turn OFF (continuous intermittent operation). Thereby, the water melt | dissolved by the defrost operation can be blown off and the amount of adhesion water of the outdoor heat exchanger 3 can be reduced. In this case, it is important to repeat the ON / OFF operation several times.

The moisture blowing function at the time of defrosting ensures the effect of the defrosting operation and is effective in preventing the subsequent deterioration of the heating performance. Further, the same effect can be obtained by mounting the installation surface of the outdoor heat exchanger 3 (surface formed by the both-side tanks) inclined with respect to the horizontal direction. That is, as shown in FIG. 4, the installation surface of the outdoor heat exchanger 3 is mounted with an inclination of θ with respect to the horizontal direction. The installation surface of the outdoor heat exchanger 3 is inclined with respect to the horizontal direction, and moisture at the time of defrosting is easily dropped. Since the tube that is originally stretched horizontally between the tanks on both sides is inclined with respect to the horizontal direction, the water droplets that hang down along the fins can easily flow out of the tube. In addition, as seen in FIG. 5, unlike normal, if the direction of the tank of the outdoor heat exchanger 3 is horizontal and the tube is vertical, water droplets flowing from the fins are transmitted vertically through the tube. It becomes easy to flow down.
In addition, the water blowing function at the time of defrosting is necessarily limited when the low water temperature radiator like this invention is arrange | positioned with respect to the outdoor heat exchanger 3 in the upstream of the air flow direction for cooling. However, it is effective even when implemented in a general defrosting operation.

  As another embodiment, in the embodiment of FIG. 2, a cooling circuit for cooling an engine or the like that cools the high-temperature heating element 1 such as an engine with a high-temperature side radiator 2, and a low-temperature heating element 11 such as an inverter or the like are used. Although the cooling circuit for the hybrid system that cools in the above is formed completely independently, it is not always necessary to form it completely independently. You may share.

1 Engine 2 High Water Temperature Radiator 3 Outdoor Heat Exchanger 6 Electric Fan 11 Inverter 12 Low Water Temperature Radiator

Claims (6)

  A vehicle heat exchanger comprising: an outdoor heat exchanger (3) of a heat pump system for a vehicle air conditioner; and a low water temperature radiator (12) for cooling a low temperature heating element (11) including an inverter for a vehicle running motor. The vehicle heat exchanger arrangement structure in which the low water temperature radiator (12) is arranged upstream of the outdoor heat exchanger (3) in the cooling air flow direction. In the vehicle heat exchanger arrangement structure, the vehicle heat exchanger arrangement structure of a hybrid vehicle further comprising a high water temperature radiator (2) for cooling engine coolant,
The vehicle according to claim 1, wherein the low water temperature radiator (12), the outdoor heat exchanger (3), and the high water temperature radiator (2) are arranged in this order from the upstream side in the cooling air flow direction. Heat exchanger arrangement structure. In the vehicle heat exchanger arrangement structure, the vehicle heat exchanger arrangement structure further comprising an electric fan (6) as a suction-type outdoor fan,
A defrosting operation is performed to remove frost adhering to the outdoor heat exchanger (3) during frost formation, and the electric fan (6) is rotated at a high speed several times or predetermined after the defrosting operation in order to blow off the dissolved water. The arrangement structure of the heat exchanger for a vehicle according to claim 1 or 2, wherein the ON / OFF operation is performed within time.   The vehicle heat exchanger arrangement structure according to claim 3, wherein the outdoor heat exchanger (3) is mounted on a vehicle with an installation surface inclined with respect to a horizontal direction.   The outdoor heat exchanger (3) includes tanks provided on both sides, a plurality of tubes spanned between the tanks, and fins provided between the tubes, and the tank is in a horizontal direction. The arrangement of the vehicle heat exchanger according to claim 3, wherein the tubes are in a vertical direction. The heat pump system is arranged in the order of the compressor (21), the indoor condenser (4), the throttle (25), the outdoor heat exchanger (3), the accumulator (24), and the compressor (21), and the refrigerant circulates. At least a refrigerant circuit is provided, and in the refrigerant circuit, an electromagnetic valve (23) is installed between the indoor condenser (4) and the outdoor heat exchanger (3) by bypassing the throttle (25). ,
In the defrosting operation, the ventilation to the indoor condenser (4) is stopped, the electromagnetic valve (23) is further opened in the refrigerant circuit, and the hot air is attached to the outdoor heat exchanger (3). The arrangement structure of the heat exchanger for vehicles according to any one of claims 3 to 5, wherein frost which has been removed is removed.

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