Vehicle structure

Abstract

To provide a vehicle structure of an electric vehicle that can reduce power consumption during air-heating.SOLUTION: A vehicle structure of an electric vehicle comprises: a heater-type air-heating circuit in which a first heat medium is circulated; a heat pump circuit in which a second heat medium is circulated; a control part that controls the circuits; an outdoor air temperature sensor; a speed sensor; and a sensing mechanism that senses a rainfall state or a snowfall state. The heat pump circuit comprises an outer capacitor, a fan, and an expansion valve. When air-heating efficiency lowers, and when the control part determines that a running condition that frost easily adheres to the outer capacitor on the basis of information from the outdoor air temperature sensor, the speed sensor, and the sensing mechanism, the control part increases the output of the heater, then stops the fan, and executes first control of stopping diffusion and inflation of the second heat medium in the expansion valve.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle structure for an electric vehicle powered by a battery. [Background technology]

[0002] Patent Document 1 discloses an air conditioning circuit for an electric vehicle. The air conditioning circuit includes a heater-type heating circuit having a heater core that heats conditioned air and a heater that heats a first heat medium supplied to the heater core. The air conditioning device further includes a heat pump circuit in which a second heat medium independent of the first heat medium is circulated. The heat pump circuit includes a heat pump-type cooling circuit and a heat pump-type heating circuit that are configured to be switchable. The heat pump-type heating circuit is configured such that the second heat medium flowing through the heat pump-type heating circuit heats the first heat medium of the heater-type heating circuit. The heat pump circuit has excellent energy-saving performance.

[0003] The heat pump circuit includes an external condenser that exchanges heat with the outside air. During heating using the heat pump circuit, a second heat medium that is cooler than the outside air temperature flows through the external condenser, transferring heat from the outside air to the second heat medium. The second heat medium that absorbs heat from the outside air heats the first heat medium in the heater-type heating circuit, and the first heat medium heats the heater core, raising the temperature of the conditioned air. A heater is used when it is desired to further raise the temperature of the conditioned air or to raise the temperature of the conditioned air quickly. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-93561 A Summary of the Invention [Problem to be solved by the invention]

[0005] Because the power consumption of a heater is large and that of a heat pump circuit is small, there is a need to actively utilize heating using a heat pump circuit in order to extend the driving range of an electric vehicle. However, when the outside temperature is low, frost is likely to form on the external condenser of the heat pump circuit. Since the frost inhibits the heat exchange of the external condenser, the heating efficiency of the heat pump circuit decreases. In that case, it is necessary to operate the heater, which shortens the driving range of the electric vehicle.

[0006] An object of the present invention is to provide a vehicle structure for an electric vehicle that can reduce power consumption during heating. [Means for solving the problem]

[0007] <1> The vehicle structure according to the embodiment of the present invention includes: A vehicle structure of an electric vehicle driven by a battery, A heater type heating circuit including a heater core that heats conditioned air and a heater that heats a first heat medium supplied to the heater core; a heat pump circuit in which a second heat medium for heating the first heat medium is circulated; A control unit that controls the heater-type heating circuit and the heat pump circuit; An outside air temperature sensor for measuring an outside air temperature; A speed sensor for measuring a vehicle speed of the electric vehicle; a detection mechanism for detecting a rainfall condition or a snowfall condition, The heat pump circuit includes an external condenser that exchanges heat with outside air, a fan that blows air to the external condenser, a compressor that compresses the second heat medium, and an expansion valve that diffuses and expands the second heat medium, The control unit is when the heating efficiency by the heat pump circuit decreases, determining whether or not the driving conditions are such that frost is likely to form on the external condenser based on information from the outside air temperature sensor, the speed sensor, and the detection mechanism; When the driving condition is satisfied, a first control is implemented in which the output of the heater is increased, the fan is stopped, and the diffusion and expansion of the second heat medium in the expansion valve is stopped.

[0008] <2> the above <1> The vehicle structure described in Further, a navigation system for acquiring navigation information including at least information regarding a current location of the electric vehicle is provided. The control unit may determine whether or not to perform the first control based on the navigation information. Effect of the Invention

[0009] the above <1> In the first control in the vehicle structure, when frost forms on the external condenser and the heating efficiency is reduced, and the driving conditions are such that frost is likely to form on the external condenser, the fan is stopped to make it difficult for outside air to hit the external condenser, and the diffusion and expansion of the second heat medium is stopped to introduce a relatively high-temperature second heat medium into the external condenser, so that the frost on the external condenser melts and the heating efficiency of the heat pump circuit is restored.

[0010] In the first control, the second heat medium is not diffused and expanded, so heating by the heat pump circuit is essentially turned off. Therefore, in the first control, heating is continued by increasing the heater output. Although power consumption increases temporarily due to the heater, the increase in power consumption can be compensated for by the energy-saving performance of heating by the heat pump circuit.

[0011] the above <2> In the above, the first control can be effectively implemented based on navigation information from a navigation system. For example, even if the frost on the external capacitor is melted by the first control while the electric vehicle is traveling on a highway, the water may refreeze due to the wind caused by the high speed of the vehicle. If the navigation information is available, it is possible to take measures such as not implementing the first control on the highway. Therefore, by effectively implementing the first control on the route from the departure point to the destination, it is possible to significantly reduce the power consumption of the electric vehicle. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing a state in which cooling is performed by the vehicle structure described in the first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a state in which heating is performed by the vehicle structure described in the first embodiment. [Diagram 3] FIG. 3 is a flowchart illustrating a procedure for reducing power consumption during heating by the vehicle structure described in the first embodiment. [Figure 4] FIG. 4 is a schematic block diagram of a vehicle structure described in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An example of an embodiment of a vehicle structure according to the present invention will be described below with reference to the drawings. The sizes of the members shown in each drawing are expressed for the purpose of clarifying the description and do not necessarily represent the actual dimensions. Note that the present invention is not limited to the following examples, but is indicated by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

[0014] <Embodiment 1> 1 and 2 show an example of a vehicle structure 1 of an electric vehicle 100 driven by a battery. The electric vehicle 100 includes a BEV (Battery Electric Vehicle), a HEV (Hybrid Electric Vehicle), and a FCEV (Fuel Cell Electric Vehicle). An FCEV is a hydrogen vehicle equipped with a fuel cell that generates electricity from hydrogen.

[0015] The vehicle structure 1 of this example includes a heat pump circuit 2 that cools and heats the air inside the vehicle, a heater-type heating circuit 3, and a control unit 4 that controls the heat pump circuit 2 and the heater-type heating circuit 3. A first heat medium 9 (Fig. 2) is circulated in the heater-type heating circuit 3. A second heat medium 8 (Figs. 1 and 2) is circulated in the heat pump circuit 2 independently of the first heat medium 9. The heat pump circuit 2 includes a cooling circuit 5 and a heating circuit 6. A part of the cooling circuit 5 and a part of the heating circuit 6 are shared. The vehicle structure 1 of this example further includes a speed sensor 48, an outside air temperature sensor 49, and a detection mechanism 15. Each component of the vehicle structure 1 of this example will be described in detail below.

[0016] <Cooling circuit in a heat pump circuit> FIG. 1 will be referred to for explaining the cooling circuit 5. In FIG. 1, the flow direction of the second heat medium 8 flowing in the cooling circuit 5 is indicated by arrows. The open arrows indicate the flow of the high-temperature second heat medium 8, the hatched arrows indicate the flow of the medium-temperature second heat medium 8 (e.g., 30° C. or higher and 50° C. or lower), and the solid arrows indicate the flow of the low-temperature second heat medium 8. The second heat medium 8 is, for example, a heat medium such as hydrofluorocarbon. The second heat medium 8 in the cooling circuit 5 functions as a refrigerant.

[0017] The cooling circuit 5 includes an external condenser 20 that exchanges heat with outside air. The cooling circuit 5 includes, in order from the external condenser 20 along the flow direction of the second heat medium 8, an expansion valve 26, an evaporator 27, a compressor 22, and an internal condenser 23. Each component will be described along the flow direction of the second heat medium 8.

[0018] More precisely, the external condenser 20 is a member that promotes heat exchange between the outside air and the second heat medium 8. During cooling, the heat of the second heat medium 8 flowing inside the external condenser 20 is released to the outside. The external condenser 20 has a plurality of fins for increasing the contact area with the outside air. The external condenser 20 has a flow path for the second heat medium 8 inside. The high-temperature second heat medium 8 flowing into the external condenser 20 releases heat to the outside air in the external condenser 20. As a result, the temperature of the second heat medium 8 discharged from the external condenser 20 becomes lower than the temperature of the second heat medium 8 flowing into the external condenser 20. A temperature sensor 41 that measures the temperature of the second heat medium 8 discharged from the external condenser 20 is disposed downstream of the external condenser 20. Information from the temperature sensor 41 is output to the control unit 4 described later and is used to control the cooling circuit 5.

[0019] The external condenser 20 is disposed on the back of the radiator 10. The radiator 10 is a heat exchanger that dissipates heat from a motor (not shown) and the like to the outside of the vehicle. The cooling circuit including the radiator 10 is not shown. The radiator 10 is disposed on the back of the grille shutter 12. When the grille shutter 12 is opened, the radiator 10 is exposed to the wind generated by the vehicle. The wind generated by the vehicle passing through the radiator 10 is exposed to the external condenser 20, where heat exchange of the second heat medium 8 is performed. Furthermore, a fan 11 is disposed on the back of the external condenser 20. When the fan 11 rotates, the outside air can be applied to the radiator 10 and the external condenser 20 even when the electric vehicle 100 is traveling at a low speed or is stopped. In this example, the fan 11 is also considered to be a part of the cooling circuit 5.

[0020] Downstream of the temperature sensor 41, the flow path of the second heat medium 8 branches. At the branch point, the flow path toward the lower side of the paper surface heads toward the expansion valve 26. A solenoid valve 21 is disposed in the flow path toward the right side of the paper surface at the branch point. During cooling, the solenoid valve 21 is closed, and the second heat medium 8 discharged from the external condenser 20 heads toward the expansion valve 26.

[0021] The expansion valve 26 diffuses and expands the second heat medium 8. The expansion valve 26 in this example is an electromagnetic valve with an adjustable throttle opening. The temperature of the diffused and expanded second heat medium 8 drops rapidly. The temperature of the diffused and expanded second heat medium 8 can be changed by adjusting the throttle amount of the expansion valve 26. A temperature sensor 42 is disposed downstream of the expansion valve 26. Information from the temperature sensor 42 is output to the control unit 4 and used to control the cooling circuit 5.

[0022] The second heat medium 8 that has been diffused and expanded flows into the evaporator 27. The evaporator 27 is a heat exchanger arranged inside a casing 2A of an HVAC (Heating Ventilation & Air Conditioning) unit. The evaporator 27 vaporizes the second heat medium 8 that has been atomized by expansion due to reduced pressure. The structure of the evaporator 27 is almost the same as that of the external condenser 20 in that it has a flow passage and multiple fins. The HVAC unit is a member that integrates air conditioning functions, and a heater core 32 (described later) is also arranged inside the casing 2A. The casing 2A has an inlet 2B that takes in outside air or inside air, and an outlet 2C that connects to a duct for air-conditioning air inside the vehicle.

[0023] An air mix door 28 and a blower 29 are disposed inside the casing 2A. The air mix door 28 is disposed so as to be able to swing or slide freely, and adjusts the mixing ratio of the cold air from the evaporator 27 and the hot air from the heater core 32 described later. During cooling, the surface of the heater core 32 facing the evaporator 27 is shielded by the air mix door 28, so that the cold air that has passed through the evaporator 27 is prevented from passing through the heater core 32. In this case, the cold air is introduced into the vehicle from the outlet 2C without being heated by the heater core 32 at all. The blower 29 is disposed between the inlet 2B and the evaporator 27, and draws in outside air or inside air from the inlet 2B.

[0024] The medium-temperature second heat medium 8 discharged from the evaporator 27 flows toward the solenoid valve 21. Since the solenoid valve 21 is closed during cooling, the second heat medium 8 flows toward the compressor 22. A temperature sensor 43 is disposed downstream of the evaporator 27. Information from the temperature sensor 43 is output to the control unit 4 and used to control the cooling circuit 5.

[0025] An accumulator 25 is disposed upstream of the compressor 22. The accumulator 25 is a device that separates an excess of the liquid second heat medium 8 in the heat pump circuit 2. By separating an excess of the liquid second heat medium 8 by the accumulator 25, damage to the compressor 22 is suppressed.

[0026] The compressor 22 is a device that compresses the second heat medium 8. The temperature of the second heat medium 8 compressed by the compressor 22 increases. The second heat medium 8 discharged from the compressor 22 flows into the internal condenser 23. A temperature sensor 44 is disposed between the compressor 22 and the internal condenser 23. Information from the temperature sensor 44 is output to the control unit 4 and used to control the cooling circuit 5.

[0027] The internal condenser 23 is a heat exchanger that heats the conditioned air with the heat of the second heat medium 8. The structure of the internal condenser 23 is almost the same as that of the external condenser 20. In this example, the internal condenser 23 is provided so as to be in contact with the second internal condenser 30 of the heater-type heating circuit 3 described later. Therefore, the heat of the internal condenser 23 is transferred to the second internal condenser 30. During cooling, the circulation of the first heat medium 9 of the heater-type heating circuit 3 is stopped, so the heat of the second internal condenser 30 does not actively heat the heater core 32 in the HVAC. The temperature of the second heat medium 8 discharged from the internal condenser 23 drops.

[0028] The second heat medium 8 discharged from the internal condenser 23 flows toward the external condenser 20. A temperature sensor 45, a pressure sensor 47, and an expansion valve 24 are arranged in this order in the flow direction of the second heat medium 8 in the piping connecting the internal condenser 23 to the external condenser 20. Information from the temperature sensor 45 and the pressure sensor 47 is output to the control unit 4 and used for controlling the cooling circuit 5.

[0029] The expansion valve 24 in this example is an electromagnetic valve with an adjustable throttle opening. During cooling, the expansion valve 24 is in a maximum open state. That is, the second heat medium 8 hardly or not at all diffuses and expands in the expansion valve 24. Therefore, the high-temperature second heat medium 8 flows into the external condenser 20 while remaining at a high temperature. The greater the difference between the outside air temperature and the temperature of the second heat medium 8 in the external condenser 20, the more efficiently the heat of the second heat medium 8 is released to the outside air.

[0030] Unlike this example, the heat pump circuit 2 may include a bypass path connecting the upstream and downstream of the expansion valve 24, and a valve capable of switching between the bypass path and a flow path toward the expansion valve 24. In this case, by operating the valve, the second heat medium 8 can be diverted to the bypass path during cooling and not flow to the expansion valve 24. In such a configuration, the expansion valve 24 may be a non-electromagnetic valve with a fixed opening.

[0031] <Heating circuit in a heat pump circuit> 2 will be referred to in explaining the heating circuit 6. In Fig. 2, arrows indicate the flow direction of the second heat medium 8 flowing in the heating circuit 6. The arrows are interpreted in the same way as in Fig. 1.

[0032] The heating circuit 6 includes an external condenser 20, a fan 11, a compressor 22, an internal condenser 23, and an expansion valve 24. The external condenser 20, the fan 11, and the compressor 22 are components shared with the cooling circuit 5. The second heat medium 8 of the heating circuit 6 is also shared with the cooling circuit 5. Below, each component will be described along the flow direction of the second heat medium 8 during heating.

[0033] During heating, the solenoid valve 21 is opened and the expansion valve 26 is closed. Therefore, the medium-temperature second heat medium 8 discharged from the external condenser 20 flows toward the compressor 22. A part of the heat of the second heat medium 8, which has been heated to a high temperature by the compressor 22, is transferred to the second internal condenser 30 in the internal condenser 23, and the first heat medium 9 flowing through the heater-type heating circuit 3 via the second internal condenser 30 is heated. This first heat medium 9 increases the temperature of the heater core 32 of the heater-type heating circuit 3, thereby heating the conditioned air. The mechanism by which the conditioned air is heated will be explained in the section on the heater-type heating circuit 3.

[0034] The second heat medium 8 discharged from the internal condenser 23 is expanded by diffusion in the expansion valve 24. The temperature of the second heat medium 8 drops rapidly due to the expansion. The temperature of the low-temperature second heat medium 8 that flows into the external condenser 20 through the expansion valve 24 rises as the external condenser 20 absorbs heat from the outside air. Here, in order to absorb heat from the outside air, the temperature of the second heat medium 8 in the external condenser 20 needs to be lower than the outside air temperature. The temperature of the second heat medium 8 that flows into the external condenser 20 can be adjusted by the opening degree of the expansion valve 24. The opening degree is determined based on information from the temperature sensor 45 and the pressure sensor 47 in the heating circuit 6.

[0035] <Heater-type heating circuit> 2, arrows indicate the flow direction of the first heat medium 9 flowing in the heater-type heating circuit 3. The arrows are viewed in the same way as in FIG.

[0036] The heater-type heating circuit 3 includes a second internal condenser 30, a heater 31, a heater core 32, a reserve tank 33, and a pump 34. The first heat medium 9 flowing through the heater-type heating circuit 3 is independent of the second heat medium 8 in the cooling circuit 5 and the heating circuit 6. In this example, the first heat medium 9 is water or antifreeze liquid. In FIG. 2, the flow direction of the first heat medium 9 is also indicated by an arrow, similar to the flow direction of the second heat medium 8. Each component will be described along the flow direction of the first heat medium 9.

[0037] The second internal condenser 30 is a heat exchanger that receives heat from the internal condenser 23 and heats the first heat medium 9 with the heat. The high-temperature first heat medium 9 discharged from the second internal condenser 30 flows into the heater core 32 through the heater 31. The heater 31 is a device that consumes power to further heat the first heat medium 9. The heater 31 is controlled based on information from a temperature sensor 46 that is arranged between the heater 31 and the heater core 32. When the temperature of the first heat medium 9 acquired by the temperature sensor 46 is sufficient to maintain the heating set temperature, the heater 31 may be turned off.

[0038] The heater core 32 is a heat exchanger disposed inside the HVAC casing 2A. The structure of the heater core 32 is substantially the same as that of the external condenser 20. During heating, at least a part of the air mix door 28 is retracted between the evaporator 27 and the heater core 32. In this case, the conditioned air introduced from the inlet 2B by the blower 29 can pass through the heater core 32. The heated conditioned air that has passed through the heater core 32 is introduced into the vehicle interior through the outlet 2C.

[0039] The first heat medium 9 that has released heat in the heater core 32 flows into the second internal condenser 30 through the reserve tank 33 and the pump 34. The reserve tank 33 removes air bubbles generated in the heater-type heating circuit 3 by cavitation. The reserve tank 33 is also used to replenish the first heat medium 9. The pump 34 pressure-feeds the first heat medium 9 to the second internal condenser 30, thereby circulating the first heat medium 9 in the heater-type heating circuit 3.

[0040] Here, when the outside air temperature is below 0°C, it is difficult to take in heat from the outside air into the heat pump circuit 2, and the heating efficiency is low. Therefore, when the outside air temperature is below 0°C, it is preferable not to perform heating using the heat pump circuit 2, but to heat the first heat medium 9 using the heater 31 of the heater-type heating circuit 3.

[0041] <Control Unit> The control unit 4 controls the operation of each component of the heat pump circuit 2 and the heater-type heating circuit 3 based on information from the temperature sensors 41, 42, 43, 44, 45, 46 and the pressure sensor 47. The control unit 4 in this example is further configured to be able to acquire information from a speed sensor 48, an outside air temperature sensor 49, and the detection mechanism 15. The speed sensor 48 detects the speed of the electric vehicle 100. The speed is determined, for example, from the rotation speed of the wheels. The outside air temperature sensor 49 measures the air temperature outside the vehicle. The outside air temperature sensor 49 is disposed, for example, on the back side of the front bumper. The detection mechanism 15 will be described later.

[0042] Each process by the control unit 4 is realized by a processing circuit including at least one processor. The processing circuit may be composed of an integrated circuit in which at least one memory, various analog circuits, and various digital circuits are combined in addition to the at least one processor. The at least one memory stores a program (instruction) that causes the at least one processor to execute each of the above processes. The at least one processor may execute each of the above processes according to the program read from the at least one memory, or may execute each of the above processes according to a logic circuit designed in advance to execute each of the above processes. The processor may be, for example, a CPU or a GPU, or any of various other processors suitable for computer control. Note that the physically separated processors may cooperate with each other to execute each of the above processes.

[0043] <Detection mechanism> The detection mechanism 15 is a mechanism for detecting a rainfall state or a snowfall state. Based on information from the detection mechanism 15, the control unit 4, which will be described later, can estimate the amount of rainfall or snowfall. The detection mechanism 15 is, for example, a mechanism for detecting the operation state of the wipers. In this case, if the wiper switch is in the "LOW" position, it can be determined that the amount of rainfall or snowfall is equal to or less than a predetermined value. If the wiper switch is in the "HIGH" position, it can be determined that the amount of rainfall or snowfall is greater than a predetermined value. The detection mechanism 15 may be a rain sensor. The rain sensor, for example, includes a light-emitting element that emits infrared light and a light-receiving element that receives the light reflected by the windshield. In this configuration, when rain or snow adheres to the windshield, the amount of reflected light entering the light-receiving element decreases. The amount of rainfall or snowfall can be determined by this change in the amount of light.

[0044] <Control to reduce power consumption during heating> The power consumption for heating by the heat pump circuit 2 is smaller than the power consumption for heating by the heater-type heating circuit 3. Therefore, in order to reduce the power consumption of the electric vehicle 100, it is preferable to mainly perform heating by the heat pump circuit 2 and reduce the output of the heater 31 or to stop the heater 31. Here, when the outside temperature is low, frost forms on the external condenser 20, reducing the heating efficiency by the heat pump circuit 2. More specifically, frost is likely to form on the external condenser 20 under driving conditions where the outside temperature is below a certain level, there is little precipitation, and the vehicle speed is equal to or higher than a predetermined value.

[0045] When the amount of rainfall or snowfall is small, water that has entered through the grill shutter 12 or the like and adheres to the external condenser 20 tends to remain adhered there, and frost is likely to form on the external condenser 20. On the other hand, when the amount of rainfall or snowfall is large, water that has adhered to the external condenser 20 tends to be continuously washed away, and frost is unlikely to form on the external condenser 20. In addition, when the vehicle speed is high, the external condenser 20 is continuously exposed to low-temperature traveling wind, and therefore water that has adhered to the external condenser 20 tends to freeze, and frost is likely to form on the external condenser 20.

[0046] In consideration of the above, when the heating efficiency by the heat pump circuit 2 decreases, the control unit 4 of the vehicle structure 1 of this example determines whether or not the driving conditions are such that frost is likely to form on the external condenser 20, and performs a specific heating control (hereinafter referred to as a first control) when the driving conditions are met. As a result, it is possible to reduce power consumption during heating. The first control will be described below based on the flowchart of FIG. 3. FIG. 2 will be referred to as necessary when describing the control.

[0047] The control unit 4 shown in FIG. 2 first judges whether or not there is a defrost request (step S1 in FIG. 3). Specifically, for example, the control unit 4 acquires the upstream temperature and downstream temperature of the external condenser 20 and calculates the temperature difference between the two. The downstream temperature is obtained, for example, from the temperature sensor 41. The upstream temperature is obtained from a temperature sensor (not shown) arranged at the inlet of the second heat medium 8 in the external condenser 20. If the temperature difference is small, it is judged that the efficiency of heat exchange in the external condenser 20 has decreased, that is, the heating efficiency of the heat pump circuit 2 has decreased. If the rate of decrease in the heating efficiency is equal to or greater than a certain value, that is, the temperature difference is equal to or less than a predetermined value, the control unit 4 judges that there is a defrost request. If there is no defrost request, the control unit 4 returns to the process of step S1.

[0048] When it is determined that there is a defrosting request, the control unit 4 determines whether or not the current conditions are such that frost is likely to form on the external condenser 20. First, the control unit 4 determines whether or not it is light rain or light snow and the outside temperature is low (step S2). Whether it is light rain or light snow can be determined by the amount of rainfall, and whether it is light snow or light snow can be determined by the amount of snowfall. Information on the amount of rainfall or snowfall is obtained by the detection mechanism 15. As already mentioned, the detection mechanism 15 may be a rain sensor or a mechanism that detects the operating state of the wipers. In this example, if the operating state of the wipers is "LOW", the control unit 4 determines that the amount of rainfall or snowfall is below a predetermined value.

[0049] Whether the outside air temperature is low or not can be determined by whether the outside air temperature is equal to or lower than a predetermined value. The outside air temperature is obtained from the outside air temperature sensor 49. The predetermined value of the outside air temperature is, for example, 5°C. If the outside air temperature is above 5°C, heat can be taken in from the outside air to the heat pump circuit 2 without lowering the temperature of the second heat medium 8 to such an extent that the water adhering to the external condenser 20 would freeze.

[0050] If there is light rain or light snow and the outside air temperature is not below a predetermined value, the control unit 4 returns to the processing of step S1. If there is light rain or light snow and the outside air temperature is below a predetermined value, the control unit 4 determines whether the vehicle speed is above a first threshold value (step S3). The first threshold value is, for example, 10 km / h. If the vehicle speed is high, a large amount of low-temperature traveling wind hits the external condenser 20, and water adhering to the external condenser 20 is likely to freeze. If the determinations in both steps S2 and S3 are "YES," it can be determined that the driving conditions are such that frost is likely to form on the external condenser 20. If the determination in step S3 is "NO," the control unit 4 returns to the control of step S1.

[0051] When the driving conditions are such that frost is likely to form on the external condenser 20, the control unit 4 starts the first control (step S4). In the first control, the output of the heater 31 is increased, the fan 11 is stopped, and the diffusion expansion of the second heat medium 8 in the expansion valve 24 is stopped. By stopping the fan 11, the force of the traveling wind hitting the external condenser 20 is reduced. In the vehicle structure 1 equipped with the grille shutter 12, the grille shutter 12 may be closed to make it difficult for the traveling wind to hit the external condenser 20. In addition, by stopping the diffusion expansion of the second heat medium 8 by the expansion valve 24, the medium-temperature second heat medium 8 discharged from the internal condenser 23 flows into the external condenser 20. As a result, the frost on the external condenser 20 melts, and the heating efficiency of the heating circuit 6 is restored.

[0052] Here, the first control may be used to dehumidify the interior of the vehicle. When dehumidifying, as shown in FIG. 1, the second heat medium 8 is sent to the evaporator 27 to reduce the saturated vapor pressure in the casing 2A and remove moisture from the conditioned air. The second heat medium 8 that has passed through the evaporator 27 passes through the compressor 22 and the internal condenser 23 and reaches the external condenser 20. The expansion valve 24 does not perform diffusion expansion. In this case, the second heat medium 8 at a relatively high temperature flows into the external condenser 20, and the frost on the external condenser 20 melts.

[0053] 2, when the second heat medium 8 is not diffusively expanded, the heating circuit 6 does not substantially function as a heater. In the first control, the output of the heater 31 is increased to maintain the temperature of the first heat medium 9 in the heater-type heating circuit 3. Therefore, the temperature of the conditioned air is maintained at the set temperature.

[0054] During the first control, the control unit 4 determines whether the vehicle speed is equal to or lower than a second threshold (step S5). The second threshold is, for example, 5 km / h. If the vehicle speed is greater than the second threshold, the control unit 4 returns to the control of step S5.

[0055] When the vehicle speed becomes equal to or lower than the second threshold value, it can be determined that the electric vehicle 100 is preparing to stop. When the vehicle speed is slow, water adhering to the external condenser 20 is less likely to freeze. The control unit 4 determines that the driving conditions are such that frost is less likely to form on the external condenser 20, stops the first control, and starts the fan 11 to flick off the water adhering to the external condenser 20. At this time, the suspension of the diffusion expansion in the expansion valve 24 continues. The higher the rotation speed of the fan 11, the easier it is to remove water from the external condenser 20. For example, the rotation speed of the fan 11 may be set to a maximum.

[0056] When the electric vehicle 100 further decelerates or stops, the control unit 4 turns on the heating circuit 6 of the heat pump circuit 2. That is, diffusive expansion starts in the expansion valve 24. Because the frost has been removed from the external condenser 20, the heating efficiency of the heating circuit 6 is high. Therefore, it is possible to reduce the output of the heater 31 or stop the heater 31. As a result, the power consumption during heating can be significantly reduced.

[0057] In the first control of this example, the power consumption during heating is reduced by turning on the heating circuit 6 of the heat pump circuit 2 at low speeds when frost is unlikely to form on the external condenser 20. Therefore, the power consumption reduction effect is easily achieved when driving in urban areas with repeated stop-and-go traffic or when stuck in traffic.

[0058] <Embodiment 2> In the configuration of the first embodiment, when traveling on a highway, it is difficult to determine the timing for performing the first control. Even if the frost on the external condenser 20 is melted while traveling on a highway, there is a risk that frost will form on the external condenser 20 in a short time when switching to heat pump heating. Therefore, in the second embodiment, a configuration for determining whether or not to perform the first control depending on the traveling state of the electric vehicle 100 will be described with reference to Fig. 4. Fig. 4 is a block diagram of the vehicle structure 1 according to the second embodiment.

[0059] The vehicle structure 1 of the first embodiment further includes a navigation system 7 in addition to the heat pump circuit 2, the heater-type heating circuit 3, the control unit 4, the speed sensor 48, the outside air temperature sensor 49, and the detection mechanism 15. The navigation system 7 outputs navigation information including information on the current location of the electric vehicle 100 to the control unit 4. The control unit 4 can determine whether or not to perform the first control by grasping the information on the current location. For example, when the electric vehicle 100 is running on a highway, it can determine not to perform the first control. On a highway, even if power is used to melt the frost on the external condenser 20, frost is likely to form on the external condenser 20 immediately. This may result in a waste of power to melt the frost. By not performing the first control while running on a highway and performing heating mainly using the heater-type heating circuit 3, it is possible to suppress unnecessary power consumption for defrosting. Even if frost forms on the external condenser 20 and the heating efficiency of the heating circuit 6 is low, it is preferable to operate the heating circuit 6 as long as the heating efficiency is not zero. This is because the output of the heater 31 is reduced by operating the heating circuit 6, and as a result, the power consumption is reduced.

[0060] Even when the electric vehicle 100 is traveling on a highway, the first control may be performed in a traffic jam. The traffic jam information is included in the navigation information, for example. The navigation system 7 acquires the traffic jam information from an Electronic Toll Collection System, a Vehicle Information and Communication System, or the like.

[0061] When the occupant sets route guidance in the navigation system 7, the navigation system 7 has information about the route from the departure point to the destination. This information is also included in the navigation information. The control unit 4 may determine in advance the position on the route where the first control is to be performed from the information about this route. When the navigation system 7 has weather information, the control unit 4 may also take the weather information into consideration when determining the position where the first control is to be performed. For example, if there is information that it will rain in a specific section on the route, the control unit 4 may determine not to perform the first control in that specific section.

[0062] According to the configuration of the second embodiment, the first control can be efficiently performed on the route from the departure point to the destination, which may result in a significant reduction in the total power consumption during use of the electric vehicle 100. [Explanation of symbols]

[0063] 1 Vehicle structure 10 radiator, 11 fan, 12 grill shutter 15 Detection mechanism 2 Heat pump circuit 2A Casing, 2B Inlet, 2C Outlet 20 external condenser, 21 solenoid valve, 22 compressor, 23 internal condenser 24,26 Expansion valve, 25 Accumulator 27 Evaporator, 28 Air mix door, 29 Blower 3 Heater type heating circuit 30 second internal capacitor, 31 heater, 32 heater core 33 Reserve tank, 34 Pump 4. Control Unit 41, 42, 43, 44, 45, 46 Temperature sensor, 47 Pressure sensor 48 Speed ​​sensor, 49 Outside air temperature sensor 5 Cooling Circuit 6 Heating Circuit 7 Navigation system 8 Second heat medium 9 First heat medium 100 Electric Vehicles

Claims

1. A vehicle structure of an electric vehicle driven by a battery, A heater type heating circuit including a heater core that heats conditioned air and a heater that heats a first heat medium supplied to the heater core; a heat pump circuit in which a second heat medium for heating the first heat medium is circulated; A control unit that controls the heater-type heating circuit and the heat pump circuit; An outside air temperature sensor for measuring an outside air temperature; A speed sensor for measuring a vehicle speed of the electric vehicle; a detection mechanism for detecting a rainfall condition or a snowfall condition, The heat pump circuit includes an external condenser that exchanges heat with outside air, a fan that blows air to the external condenser, a compressor that compresses the second heat medium, and an expansion valve that diffuses and expands the second heat medium, The control unit is when the heating efficiency by the heat pump circuit decreases, determining whether or not the driving conditions are such that frost is likely to form on the external condenser based on information from the outside air temperature sensor, the speed sensor, and the detection mechanism; When the driving condition is satisfied, a first control is executed to increase an output of the heater, stop the fan, and stop the diffusion and expansion of the second heat medium in the expansion valve. Vehicle structure.

2. Further, a navigation system for acquiring navigation information including at least information regarding a current location of the electric vehicle is provided. The vehicle structure according to claim 1 , wherein the control unit determines whether or not to implement the first control based on the navigation information.

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