Heat medium heating device

Abstract

To provide a heat medium heating device capable of keeping a plurality of power switching elements in an appropriate temperature zone to control the energization of an electric heater.SOLUTION: A heat medium heating device 1 includes heat medium flow paths 9, 11 provided in a casing 2, electric heaters 18, 19 for heating heat medium flowing in the heat medium flow paths, and a power switching elements 22-24 for controlling the energization of the electric heaters, the power switching elements being each arranged in a heat exchange relation with the heat medium flowing in the heat medium flow path, the power switching element 24 having the greatest amount of heat to be generated by the energization, out of the power switching elements, being arranged on the upstream side with respect to the flow of the heat medium, with respect to the other power switching elements 22, 23.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a heat medium heating device that uses an electric heater to heat a heat medium flowing through a heat medium flow path formed in a housing. [Background technology]

[0002] Conventionally, a heat medium heating device used for air conditioning the interior of a vehicle has a heat medium flow path formed in a housing, and a cylindrical electric heater called a cartridge heater is arranged in the heat medium flow path to heat the heat medium flowing through the heat medium flow path. In this case, for example, two heat medium flow paths are provided in the housing, one end of each of which is connected by a communication flow path, and an electric heater is arranged in each heat medium flow path, and the heat medium flowing in from a heat medium inlet portion formed at the other end of one heat medium flow path is heated by each electric heater, and then the heat medium flows out from a heat medium outlet portion formed at the other end of the other heat medium flow path (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2016-536197 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the current supply to each electric heater is controlled by a power switching element such as an IGBT, but it is also assumed that a power switching element that adjusts the total power of the two electric heaters will be provided in addition to these.In that case, the currents that flow through each power switching element will join and flow in the power switching element that adjusts the total power, so there is a risk of the greatest heat generation and failure.

[0005] The present invention has been made to solve the above-mentioned conventional technical problems, and aims to provide a heat medium heating device that can maintain a plurality of power switching elements that control the flow of current to an electric heater within an appropriate temperature range. [Means for solving the problem]

[0006] In order to solve the above problems, the heat medium heating device of the present invention comprises a heat medium flow path provided in a housing, an electric heater for heating the heat medium flowing through the heat medium flow path, and a plurality of power switching elements for controlling the supply of current to the electric heater, and is characterized in that each power switching element is disposed in a heat exchange relationship with the heat medium flowing through the heat medium flow path, and that among the power switching elements, a power switching element which generates the greatest amount of heat when current is applied is disposed upstream of the flow of the heat medium relative to the other power switching elements.

[0007] The heat medium heating device of the invention of claim 2 is characterized in that in the above invention, a plurality of heat medium flow paths are provided in a housing, an electric heater is disposed in each heat medium flow path, and a power switching element is provided for controlling the supply of electricity to each electric heater.

[0008] The heat medium heating device of the invention of claim 3 is characterized in that it comprises a specific power switching element through which currents flowing through each power switching element in the above invention are joined together, and this specific power switching element is arranged upstream of the other power switching elements with respect to the flow of the heat medium.

[0009] The heat medium heating device of the invention of claim 4 is characterized in that it is provided within a housing in the above invention and includes a control board on which a control device for controlling the electric heaters is mounted, and the control device controls the supply of electricity to the electric heaters by power switching elements for controlling the supply of electricity to each electric heater, and adjusts the overall power of each electric heater by a specific power switching element. Effect of the Invention

[0010] According to the present invention, in a heat medium heating device including a heat medium flow path provided in a housing, an electric heater for heating the heat medium flowing through the heat medium flow path, and a plurality of power switching elements for controlling the supply of electricity to the electric heater, each power switching element is disposed in a heat exchange relationship with the heat medium flowing through the heat medium flow path, so that each power switching element is cooled by the heat medium and the heat medium is heated.

[0011] In this case, among the power switching elements, the power switching element that generates the greatest amount of heat when current is passed through it is positioned upstream of the flow of the heat medium relative to the other power switching elements. Therefore, the power switching element that generates the greatest amount of heat exchanges heat with the heat medium with the lowest temperature that has flowed into the heat medium flow path, and is efficiently cooled, while the heat medium is effectively heated.

[0012] This makes it possible to efficiently heat the heat medium and to maintain all of the power switching elements in an appropriate temperature range, thereby making it possible to avoid failure of the power switching elements.

[0013] For example, in the case where a plurality of heat medium flow paths are provided within the housing as in the invention of claim 2, and an electric heater is disposed in each heat medium flow path, and where power switching elements are provided for controlling the supply of current to each electric heater, and a specific power switching element through which the currents flowing through each power switching element are joined as in the invention of claim 3, this specific power switching element is disposed upstream of the other power switching elements in terms of the flow of the heat medium.

[0014] As in the invention of claim 4, the control device controls the power supply to the electric heaters, for example, by power switching elements for controlling the power supply to each electric heater, and the total power to each electric heater is adjusted by a specific power switching element. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view showing the appearance of a heat medium heating device according to an embodiment of the present invention; [Diagram 2] 2 is a schematic cross-sectional plan view for explaining a flow path of a heat medium in the heat medium heating device of FIG. 1. FIG. [Diagram 3] FIG. 2 is a plan view showing the inside of the heat medium heating device of FIG. [Figure 4] FIG. 4 is a vertical sectional side view of the heat medium heating device corresponding to FIG. 3. [Diagram 5] 2 is an electric circuit diagram of a control device for the heat medium heating device in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a perspective view showing the appearance of a heat medium heating device 1 according to an embodiment of the present invention, Fig. 2 is a schematic cross-sectional view for explaining the flow of heat medium in the heat medium heating device 1, Fig. 3 is a plan view showing the inside of the main body 3 of the housing 2 with the cover 4 of the heat medium heating device 1 in Fig. 1 removed, and Fig. 4 is a vertical cross-sectional side view of Fig. 3.

[0017] The heat medium heating device 1 of the embodiment is used for conditioning the interior of a vehicle (not shown), and a housing 2 is composed of a main body 3 and a cover 4 attached to the main body 3. In the embodiment, two flow path sections 6, 7 (made of metal) are arranged side by side within the main body 3 of the housing 2, spaced apart from each other with a gap 8 therebetween, and heat medium flow paths 9, 11 are formed within them, respectively. That is, the heat medium flow paths 9, 11 are arranged spaced apart from each other with a gap 8 therebetween.

[0018] A communication section 13 having a communication flow path 12 formed therein is connected to one end of the flow path sections 6, 7, and one end of both heat medium flow paths 9, 11 are connected to each other by this communication flow path 12. A heat medium inlet section 16 is connected to the other end of one heat medium flow path 9, and a heat medium outlet section 17 is connected to the other end of the other heat medium flow path 11.

[0019] In each figure, 18 and 19 are rod-shaped electric heaters (heat generating elements) constituted by cartridge heaters (cylindrical heaters) in this embodiment, and the electric heater (electric heater 1) 18 is inserted into one heat medium flow path 9 with a gap between it and the inner surface of the flow path section 6, while the electric heater (electric heater 2) 19 is inserted into the other heat medium flow path 11 with a gap between it and the inner surface of the flow path section 7.

[0020] A control board 21 is provided at a position on the cover 4 side of each of the flow passage sections 6, 7 in the main body 3. On this control board 21, a power switching element 22 (IGBT1) for controlling the supply of electricity to the electric heater 18, a power switching element 23 (IGBT2) for controlling the supply of electricity to the electric heater 19, and a power switching element 24 (IGBT3) for adjusting the overall power of each of the electric heaters 18, 19 are mounted.

[0021] In this embodiment, the plurality of power switching elements 22 to 24 are configured with IGBTs. A capacitor 26 and a choke coil 27 that configure a noise filter 25 are also mounted on the control board 21. The capacitor 26 and the choke coil 27 are circuit components that are larger in size than the power switching elements 22 to 24. The power switching elements 22 to 24, the capacitor 26, the choke coil 27, etc. configure a control device 31 (FIG. 5) of the heat medium heating device 1.

[0022] Moreover, each of the power switching elements 22-24 is mounted on the surface of the control board 21 on the side of each of the flow passage sections 9, 11, and is attached in a heat exchanging manner to the flow passage section 6. As a result, each of the power switching elements 22-24 is disposed in a heat exchanging relationship with the heat medium flowing in the heat medium flow passage 9. Furthermore, the power switching element 24 (a specific power switching element) is disposed upstream of the other power switching elements 22, 23 with respect to the flow of the refrigerant (FIG. 3).

[0023] Furthermore, a capacitor 26 and a choke coil 27 are also mounted on the surface of the control board 21 on the side of each of the flow path sections 9 and 11, and are inserted and arranged in the space 8 between the flow path section 6 (heat medium flow path 9) and the flow path section 7 (heat medium flow path 11) (FIGS. 3 and 4).

[0024] Next, Fig. 5 shows the electric circuit of the control device 31. The noise filter 25 mentioned above is connected to a vehicle battery (DC power source) not shown. The power switching element 22 and the electric heater 18 are connected in series, and the power switching element 23 and the electric heater 19 are connected in series, and these two series circuits are connected in parallel. The power switching element 24 is connected in series to these parallel circuits, and a current sensor 32 is connected in series to the power switching element 24.

[0025] The power switching elements 22 and 23 are connected to the positive electrode side of the noise filter 25, and the current sensor 32 is connected to the negative electrode side. As a result, the currents that have flowed through the two power switching elements 22 and 23 join together and flow through the power switching element 24.

[0026] 5, reference numeral 36 denotes a control unit constituted by a microcomputer, and drivers 37, 38, and 39 are connected to the output of this control unit 36. Driver 37 is connected to the gate of power switching element 22, and driver 38 is connected to the gate of power switching element 23. Driver 39 is connected to the gate of power switching element 24.

[0027] The control unit 36 ​​receives the output of the current sensor 32, as well as the outputs of the inlet temperature sensor 41 and the outlet temperature sensor 42. The inlet temperature sensor 41 detects the temperature of the heat medium flowing into the heat medium flow passage 9 from the heat medium inlet portion 16, and the outlet temperature sensor 42 detects the temperature of the heat medium flowing out from the heat medium outlet portion 17. In this application, the heat medium flowing in from the heat medium inlet portion 16 means the heat medium immediately before or immediately after entering the heat medium inlet portion 16, and the heat medium flowing out from the heat medium outlet portion 17 means the heat medium immediately before or immediately after exiting the heat medium outlet portion 17.

[0028] Next, the operation of the heat medium heating device 1 configured as above will be described. A heat medium circuit (not shown) is connected to the heat medium inlet section 16, and the heat medium (water in this embodiment) flows from the heat medium inlet section 16 into the heat medium flow path 9 by a pump (not shown). The heat medium that has flowed into the heat medium flow path 9 flows into the heat medium flow path 11 via the communication flow path 12, and flows out from the heat medium outlet section 17 to the heat medium circuit described above.

[0029] On the other hand, the control unit 36 ​​of the control device 31 controls the switching of the power switching elements 22-24 by the drivers 37-39 based on the outputs of the inlet temperature sensor 41, the outlet temperature sensor 42, and the current sensor 32. As a result, electricity is applied to the electric heaters 18, 19, and the electric heaters 18, 19 generate heat, so that the heat medium that has flowed into the heat medium flow path 9 is heated in the process of passing around the electric heater 18, and is further heated in the process of passing around the electric heater 19 after entering the heat medium flow path 11.

[0030] A heater core provided in the HV unit of the vehicle is connected to the heat medium circuit described above, and the heat medium heated by the heat medium heating device 1 is circulated through this heater core. Air supplied to the vehicle cabin is passed through the heater core, thereby heating the cabin.

[0031] The control unit 36 ​​controls the switching of the power switching elements 22, 23 based on the temperature of the inflowing heat medium detected by the inlet temperature sensor 41 and the temperature of the outflowing heat medium detected by the outlet temperature sensor 42, and controls the supply of electricity to each of the electric heaters 18, 19. The currents flowing through these power switching elements 22, 23 (electric heaters 18, 19) join together and flow to a power switching element (specific power switching element) 24. Based on the value of this joined current detected by the current sensor 32, the control unit 36 ​​controls the switching of the power switching element 24 to adjust the overall power of each of the electric heaters 18, 19.

[0032] Here, the currents flowing through the power switching elements 22, 23 are joined together and flow through the power switching element 24 (a specific power switching element), so that the power switching element 24 generates more heat than the power switching elements 22, 23 and thus generates the greatest amount of heat. However, since the power switching element 24 is disposed upstream of the other power switching elements 22, 23 with respect to the flow of the heat medium, the power switching element 24 exchanges heat with the heat medium with the lowest temperature that has flowed into the heat medium flow path 9.

[0033] As a result, the heat of the power switching element 24, which generates the greatest amount of heat, is smoothly transferred to the heat medium, so that the power switching element 24 is effectively cooled and the temperature of the heat medium is efficiently increased by the heat of the power switching element 24. Note that the heat generated by the power switching elements 22 and 23 is also transferred to the heat medium downstream of the power switching element 24, so that the power switching elements 22 and 23 are also cooled and the temperature of the heat medium further increases.

[0034] As a result, the heat medium can be efficiently heated, and all of the power switching elements 22-24 can be maintained in an appropriate temperature range, making it possible to avoid failure of the power switching elements 22-24.

[0035] As described above, in the heat medium heating device 1, the heat medium flow paths 9, 11 are arranged at a distance from each other, so that there is no heat exchange between the heat medium flow paths 9, 11. As a result, even when the temperature of the heat medium flowing in from the heat medium inlet part 16 is detected by the inlet temperature sensor 41 as in the embodiment and the electric heaters 18, 19 are controlled based on the temperature, it is possible to avoid the inconvenience of detecting an erroneous temperature.

[0036] Furthermore, even when the electric heaters 18, 19 are disposed in the heat medium flow paths 9, 11, respectively, as in the embodiment, to heat the heat medium flowing in from the heat medium inlet portion 16 and to cause the heat medium to flow out from the heat medium outlet portion 17, it is possible to avoid the inconvenience that the outflowing refrigerant is cooled by the inflowing refrigerant.

[0037] In particular, a control board 21 on which circuit components constituting a control device 31 for controlling the electric heaters 18, 19 are mounted is provided inside the housing 2, and the capacitor 26 and the choke coil 27, which are circuit components constituting a noise filter 25 of this control board 21, are arranged within the space 8 between each of the heat medium flow paths 9, 11. As a result, the dead space (space 8) between each of the heat medium flow paths 9, 11 can be effectively utilized for arranging the circuit components, thereby realizing a compact heat medium heating device 1.

[0038] In particular, in the embodiment, the capacitor 26 and the choke coil 27, which are circuit components larger in size than the power switching elements 22 to 24, are disposed within the space 8, so that the overall size of the device can be effectively reduced. Even if the capacitor 26 or the choke coil 27 needs to be changed in accordance with the required specifications, the heat medium heating device 1 can be accommodated within the space 8 without increasing its size, so that the degree of freedom in design is increased.

[0039] On the other hand, since the power switching elements 22-24 are arranged in a heat exchange relationship with the heat medium, the heat medium is heated by the heat generated by the power switching elements 22-24, and the power switching elements 22-24 themselves can be cooled.

[0040] In the embodiment, the capacitor 26 and the choke coil 27 are disposed within the gap 8, but only one of them is effective. Also, in the embodiment, the inlet temperature sensor 41 and the outlet temperature sensor 42 are provided to control the energization of the electric heaters 18, 19, but control may be performed using only the inlet temperature sensor 41 or only the outlet temperature sensor 42.

[0041] Furthermore, in the embodiment, an example having two heat medium flow paths 9 and 11 has been described, but the present invention is also effective in the case where more heat medium flow paths are configured and arranged at a distance from each other. In addition, in the embodiment, the power switching elements 22 to 24 are configured with IGBTs, but they may be configured with MOSFETs or the like. In addition, in the embodiment, a heat medium heating device used for vehicle air conditioning has been taken as an example, but it goes without saying that the heat medium heating device 1 is effective in any heating system that uses a heat medium. [Explanation of symbols]

[0042] 1 Heat medium heating device 2. Chassis 8 intervals 9, 11 Heat transfer medium flow path 12 Connecting flow path 16 Heat medium inlet 17 Heat medium outflow part 18, 19 Electric heater 21 Control Board 22~24 Power switching elements 25 Noise Filter 26 Capacitor 27 Choke coil 31 Control device 32 Current Sensor 36 Control Unit 41 Inlet temperature sensor 42 Outlet temperature sensor

Claims

1. A heat medium heating device including a heat medium flow path provided in a housing, an electric heater for heating a heat medium flowing through the heat medium flow path, and a plurality of power switching elements for controlling energization of the electric heater, a heat medium heating device, characterized in that each of the power switching elements is disposed in a heat exchange relationship with a heat medium flowing through the heat medium flow path, and a power switching element which generates the largest amount of heat when energized is disposed upstream of the flow of the heat medium relative to the other power switching elements.

2. 2. The heat medium heating device according to claim 1, wherein a plurality of the heat medium flow paths are provided in the housing, the electric heater is disposed in each of the heat medium flow paths, and the power switching element is provided for controlling the supply of electricity to each of the electric heaters.

3. a specific power switching element through which currents flowing through the respective power switching elements join together, 3. The heat medium heating device according to claim 2, wherein the specific power switching element is arranged upstream of the other power switching elements with respect to the flow of the heat medium.

4. a control board provided in the housing and having a control device mounted thereon for controlling the electric heater; 4. The heat medium heating device according to claim 3, wherein the control device controls the energization of the electric heaters by power switching elements for controlling the energization of each of the electric heaters, respectively, and adjusts the overall power of each of the electric heaters by the specific power switching element.

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