Heating control device and control program, fluid heating unit, heating cycle device and vehicle air conditioning system equipped therewith

Abstract

[Problem] The purpose of the present disclosure is to provide a heating control device capable of performing control with small fluctuations in temperature with respect to the target temperature and such that a target temperature is rapidly reached, and also to provide a heating cycle device and a vehicle air conditioner equipped therewith. [Solution] A heating control device 6 according to the present disclosure controls a transistor 5 that supplies power by switching operation to a heater 4 that heats a coolant, the heating control device adjusting the heating amount of the heater on the basis of a heating amount control profile that has a decreasing portion in which the heating amount decreases as the coolant temperature rises, the decreasing portion having a first decreasing portion and a second decreasing portion each having a negative slope, the first decreasing portion and the second decreasing portion having the same heating amount at the target temperature, the first decreasing portion having a first region and a second region, and the slope at any temperature within the second region being negative with respect to the slope at any temperature within the first region.

Description

Technical Field

[0001] The present disclosure relates to a heating control device, a control program, a fluid heating unit, a heating cycle device, and a vehicle air conditioner including the same.

Background Art

[0002] Conventionally, a vehicle air conditioner using a hot water heating device that performs heating using hot water has been known (see, for example, Patent Document 1). In the vehicle air conditioner of Patent Document 1, a first switch and a second switch are provided, and the target temperature of the hot water when activated by the second switch is set to a value lower than the target temperature of the hot water when activated by the first switch, so that a comfortable heating temperature can be obtained during heating when the temperature inside the vehicle is high.

[0003] In addition, as a heater for a hot water heating device, a fluid heating unit that heats a fluid by an electric heater has been disclosed (see, for example, Patent Document 2).

[0004] As a method for controlling the amount of power supplied to an electric heater, a method of performing duty control on the DC power obtained from a battery by an inverter and supplying it is known (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, electric vehicles (EVs) that run solely on electric motors, hybrid electric vehicles (HEVs) that run on multiple power sources including electric motors and internal combustion engines, and vehicles in which the internal combustion engine only generates electricity and the vehicle is driven by an electric motor powered by that electricity have become widespread.

[0007] In the case of electric vehicles, since they do not have an engine, the total amount of coolant in the coolant loop is less than 10 liters, which is less than that of vehicles with an engine. The flow rate of coolant in the coolant loop is actually about 10 liters / minute, although it fluctuates, and the entire fluid circulates in less than a minute. For this reason, if temperature hunting occurs at the outlet point of the fluid heating unit, the hunting effect is more likely to spread throughout the entire path due to the small total amount of coolant, and there is a need to stabilize the temperature by controlling it more precisely than in vehicles with an engine.

[0008] Furthermore, in the case of hybrid vehicles or vehicles with internal combustion engines that can be driven by electric motors, although the total coolant volume is greater than that of electric vehicles, there is a demand to reduce the coolant volume to reduce the total vehicle weight, and the total coolant volume is tending to decrease. For this reason, if temperature hunting occurs at the heater outlet point, the hunting effect is likely to spread throughout the entire coolant path.

[0009] For example, in Figure 2 of the vehicle air conditioning system in Patent Document 1, the temperature change of the hot water is controlled to within ±5°C of the target temperature. However, in vehicles with a small total coolant volume, it is necessary to reduce the temperature change to a smaller value, such as ±1°C of the target temperature.

[0010] This disclosure aims to provide a heating control device and control program, a fluid heating unit, a heating cycle device, and a vehicle air conditioning system equipped therewith, which can reach a target temperature early and control the temperature with minimal fluctuation relative to the target temperature. [Means for solving the problem]

[0011] The heating control device according to the present invention controls a transistor that supplies power by switching operation to a heater that heats coolant, which generates heat when energized and is supplied to a radiator mounted on a vehicle air conditioning system, wherein the heating control device controls the switching operation of the transistor based on a heating amount control profile, and adjusts the amount of heating by the heater by changing the on-off duty cycle of the transistor, wherein the heating amount control profile is a function that shows the relationship between the temperature of the coolant and the amount of heating by the heater, and the temperature rises from the low temperature side to the high temperature side, crossing the target temperature of the coolant The heating amount is reduced, and the reducing portion comprises a first reducing portion when the temperature is in a temperature range below the target temperature, and a second reducing portion when the temperature is in a temperature range above the target temperature, and the first reducing portion and the second reducing portion have the same heating amount at the target temperature, and both the first reducing portion and the second reducing portion have a negative slope in the function, and the first reducing portion comprises a first region and a second region on the higher temperature side of the first region, and the slope of the heating amount control profile at any temperature in the second region is characterized in that the negative slope is greater than the slope of the heating amount control profile at any temperature in the first region.

[0012] In the heating control device according to the present invention, the reduction portion is a curve having an inflection point, and the temperature at the inflection point includes a form in which it coincides with the target temperature.

[0013] In the heating control device according to the present invention, the reduction portion is a curve having an inflection point, and the temperature at the inflection point includes a form in which the temperature is higher than the target temperature.

[0014] In the heating control device according to the present invention, the decreasing portion is a curve having an inflection point, the temperature at the inflection point is lower than the target temperature, and the second region includes a configuration in which the region is on the lower temperature side of the inflection point.

[0015] In the heating control device according to the present invention, both the first region and the second region include a form in which the function is a linear function with different slopes from each other.

[0016] In the heating control device according to the present invention, the reduction portion includes a form in which the curve does not have an inflection point.

[0017] In the heating control device according to the present invention, the heating amount control profile includes a configuration in which, on the lower temperature side than the first reduction section, the heating amount remains constant even when the temperature rises from the lower temperature side to the higher temperature side.

[0018] In the heating control device according to the present invention, it is preferable that the second reduction unit has a heat dissipation corresponding region on the side of the target temperature that is higher than the target temperature, which maintains the heating amount at a predetermined heating amount.

[0019] The fluid heating unit according to the present invention comprises a heater that generates heat when an electric current is applied to heat a coolant, a transistor that supplies power to the heater by switching operation, and a heating control device according to the present invention, wherein the heating control device controls the switching operation of the transistor.

[0020] The heating cycle device according to the present invention comprises a circulation channel, a coolant filled in the circulation channel, a pump for circulating the coolant in the circulation channel, a fluid heating unit according to the present invention for temperature control of the coolant, and a heat sink for dissipating heat from the coolant, wherein the coolant is heated in the fluid heating unit by energizing the heater with a transistor.

[0021] The vehicle air conditioning system according to the present invention is a vehicle air conditioning system that is mounted on a vehicle and comprises a heating cycle device according to the present invention, wherein the vehicle is capable of being driven by an electric motor, and the vehicle air conditioning system has a temperature control unit that adjusts the temperature of the air supplied to the passenger compartment, and the radiator is a hot water type heat exchanger arranged inside the temperature control unit.

[0022] The control program according to the present invention causes the heating control device according to the present invention to execute a process of controlling the switching operation of the transistor based on the heating amount control profile.

Effect of the Invention

[0023] According to the present disclosure, it is possible to provide a heating control device, a control program, a fluid heating unit, a heating cycle device, and a vehicle air conditioner including the same, which can achieve control that reaches the target temperature early and has small temperature fluctuations with respect to the target temperature.

Brief Description of the Drawings

[0024] [Figure 1] It is a block diagram showing an example of a fluid heating unit, a heating cycle device, and a vehicle air conditioner including the same according to the present embodiment. [Figure 2] It is a diagram showing a first example of a heating amount control profile. [Figure 3] It is a diagram showing a second example of a heating amount control profile. [Figure 4] It is a diagram showing a third example of a heating amount control profile. [Figure 5] It is a diagram showing a fourth example of a heating amount control profile. [Figure 6] It is a diagram showing a fifth example of a heating amount control profile. [Figure 7] It is a diagram showing a first example of a profile excluded from the heating amount control profile. [Figure 8] It is a diagram showing a second example of a profile excluded from the heating amount control profile. [Figure 9] It is a diagram showing a third example of a profile excluded from the heating amount control profile. [Figure 10] It is a diagram showing a fourth example of a profile excluded from the heating amount control profile. [Figure 11]This figure shows an example of duty cycle control for a heating cycle system, where (a) shows duty cycle control in a constant region, (b) shows duty cycle control at an arbitrary temperature in a decreasing region, and (c) shows duty cycle control at an arbitrary temperature in the heat dissipation range. [Figure 12] This figure shows the relationship between heating time and coolant temperature in Example 1. [Figure 13] This figure shows the relationship between heating time and coolant temperature in Comparative Example 1. [Figure 14] This figure shows the relationship between heating time and coolant temperature in Comparative Example 2. [Modes for carrying out the invention]

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to these embodiments. In this specification and drawings, components with the same reference numerals refer to the same components. Various modifications to the present invention are possible as long as the effects of the present invention are achieved.

[0026] Figure 1 is a block diagram showing an example of a heating cycle device and a vehicle air conditioning system equipped therewith according to this embodiment. The heating control device 6 according to this embodiment is a heating control device that controls a transistor 5 that supplies power by switching operation to a heater 4 that heats the coolant supplied to a radiator 7 mounted on the vehicle air conditioning system 900, which generates heat when energized. The heating control device 6 controls the switching operation of the transistor 5 based on the heating amount control profile 100 (100A to 100E) shown in Figures 2 to 6, and adjusts the amount of heating by the heater 4 by changing the on-off duty cycle of the transistor 5. The heating amount control profile 100 (100A to 100E) is a function that shows the relationship between the coolant temperature T and the amount of heating E by the heater, and as the temperature T rises from the low temperature side to the high temperature side across the target temperature Tt of the coolant... The heating amount E decreases as the heating amount E decreases, and the heating amount E decreases as the heating amount E decreases. The heating amount E decreases as the heating amount E decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases as the heating amount decreases. The heating amount E decreases. The heating amount

[0027] The fluid heating unit 10 according to this embodiment includes a heater 4 that generates heat when energized to heat the coolant, a transistor 5 that supplies power to the heater 4 through a switching operation, and a heating control device 6 according to this embodiment, the heating control device 6 controls the switching operation of the transistor 5.

[0028] The fluid heating unit 10 uses a transistor 5 to supply power to a heater 4, which generates heat that heats the coolant supplied to the radiator 7 of the vehicle's air conditioning system. At this time, the heating control device 6 controls the switching operation of the transistor 5 based on the heating amount control profile 100 (100A~100E), and adjusts the amount of heating by the heater 4 by changing the on-off duty cycle of the transistor 5, thereby controlling the temperature of the coolant.

[0029] The heating cycle device 1 according to this embodiment comprises a circulation channel 2, coolant filled in the circulation channel 2, a pump 3 for circulating the coolant in the circulation channel 2, a fluid heating unit 10 according to this embodiment for controlling the temperature of the coolant, and a heat sink 7 for dissipating heat from the coolant. The coolant is heated in the fluid heating unit 10 by energizing a heater 4 via a transistor 5.

[0030] The heating cycle device 1 is a device that generates warm air for heating in a vehicle air conditioning system by exchanging heat between coolant, whose temperature is controlled by a fluid heating unit 10, and air passing through a radiator 7.

[0031] The circulation path 2 includes a pipe 12 connecting the coolant outlet of the radiator 7 to the pump 3, and a pipe 13 connecting the pump 3 to the tank inlet 10b. The coolant is supplied by a pipe 11 pump 3 connecting the outlet 10a of a tank (not shown) containing a heater 4 to the coolant inlet of the radiator 7, and introduced through the pipe 13 from the inlet 10b into the heating chamber in the tank (not shown), where it is heated by the heater 4 built into the tank. Subsequently, the heated coolant is discharged from the tank outlet 10a, sent through the pipe 11 to the radiator 7, and released to warm the air used for air conditioning. After passing through the radiator 7, the coolant is drawn into the pump 3 through the pipe 12 and circulated.

[0032] The coolant (not shown) is liquid at room temperature and is, for example, a heat transfer medium obtained by dissolving ethylene glycol or glycerin in water.

[0033] The fluid heating unit 10 includes a heater 4, a tank (not shown) housing the heater 4, and a transistor 5 positioned on the upper wall of the tank, similar to the fluid control unit described in Patent Document 2.

[0034] The heater 4 is an electrically heated element that generates heat when energized, and is not particularly limited; for example, a sheathed heater in which a nichrome wire is encased in a metal pipe can be used. The tank has a heating chamber through which coolant flows and which houses the heater 4. Coolant before heating is introduced into the heating chamber via an inlet 10b, and the heated coolant is discharged via an outlet 10a. Preferably, the heating chamber has a temperature sensor 50 near the outlet 10a to detect the temperature T of the heated coolant. It is more preferable that the temperature sensor 50 is provided at the outlet 10a.

[0035] The transistor 5 is preferably an insulated gate bipolar transistor (IGBT). The transistor 5 is electrically connected to the battery 8. The transistor 5 is also electrically connected to the control device 6 and switches in response to command signals from the heating control device 6. The transistor 5 controls the power supply to the heater 4 through its switching operation. By changing the on-off duty cycle of the transistor 5, the amount of heating by the heater 4 can be adjusted, and the amount of heat supplied to the coolant can be adjusted. The fluid heating unit 10 is configured to have at least the heater 4, the transistor 5, the heating control device 6, and electrical wiring 51 that connects these to the battery 8 and constitutes an electrical circuit.

[0036] The heating control device 6 controls the switching operation of the transistor 5 based on the heating amount control profile 100 (100A~100E).

[0037] The control program according to this embodiment causes the heating control device 6 according to this embodiment to execute a process to control the switching operation of the transistor 5 based on the heating amount control profile (100 (100A~100E)). The heating control device 6 has a memory unit (not shown) and functions as a heating control device by executing a control program read from the memory unit. The execution of the control program includes, for example, the following process. First, the current temperature T of the coolant is detected and applied to the heating amount control profile (100 (100A~100E)) to read the "heating amount E by the heater 4" corresponding to the current temperature T. Next, as shown in Figure 11, duty control is performed to control the transistor 5 so that the "heating amount E corresponding to the current temperature T" is supplied to the heater 4.

[0038] Radiator 7 is a hot water type heat exchanger.

[0039] Instead of installing the temperature sensor 50 in the fluid heating unit 10, it may also be installed in the piping 11 that connects the outlet 10a of the tank (not shown) housing the heater 4 to the coolant inlet of the radiator 7, as part of the circulation circuit 2.

[0040] The heating amount control profile 100 (100A~100E) is a function that shows the relationship between the coolant temperature T and the heating amount E by the heater, as shown in Figures 2 to 6. In Figures 2 to 6, the heating amount control profile 100 (100A~100E) is displayed as a graph with the coolant temperature T on the horizontal axis and the heating amount E by the heater 4 on the vertical axis. The coolant temperature T is preferably, for example, the temperature of the coolant delivered from the outlet 10a of the fluid heating unit 10, and its unit is, for example, °C. The heating amount E by the heater 4 is a value adjusted by, for example, the on-off duty cycle of the transistor 5, and its unit is, for example, KW / h.

[0041] The reduction section 110 is the portion where the amount of heating E decreases as the temperature T rises from the low temperature side to the high temperature side, crossing the target temperature Tt of the coolant. In Figures 2 to 6, the reduction section 110 is the temperature range from the temperature T1 at which the amount of heating E begins to decrease to the temperature Te at which the amount of heating E approaches zero or the temperature (not shown) at which the amount of heating E becomes zero. The temperature T1 at which the reduction section 110 begins is preferably {target temperature Tt}-10°C, and more preferably {target temperature Tt}-8°C. The target temperature Tt is, for example, 80 to 85°C.

[0042] The first reduction section 111 is a temperature range within the reduction section 110 from the temperature T1 at which the amount of heat E begins to decrease to a temperature Tt or lower. The first reduction section 111 has a first region 111A and a second region 111B that is at a higher temperature than the first region 111A. The boundary between the first region 111A and the second region 111B is not particularly limited, and in Figure 2, as an example, the boundary is set to a temperature T3 obtained by bisecting the range between the temperature T1 at which the reduction section 110 starts and the target temperature Tt, but it may be any temperature.

[0043] The second reduction section 112 is a temperature range within the reduction section 110 up to a temperature Te where the amount of heating E approaches zero above the target temperature Tt, or a temperature (not shown) where the amount of heating E becomes zero.

[0044] As shown in Figures 2 to 6, the first reduction section 111 and the second reduction section 112 have the same heating amount E at the target temperature Tt. For this reason, as shown in Figure 7 or Figure 8, profiles 200 and 201 in which the heating amount decreases at the target temperature Tt are excluded from the heating amount control profile 100. Figure 7 is a simple on / off control, and Figure 8 is a modified example of Figure 7. In profiles 200 and 201 as shown in Figure 7 or Figure 8, the heating amount E decreases sharply at the target temperature Tt, resulting in a large temperature fluctuation relative to the target temperature. This is because the coolant is heated by the heat sink 7, and if the heating amount is suddenly set to "zero" just because it has risen in temperature to reach the target temperature Tt, the coolant temperature T will drop sharply from the target temperature.

[0045] As shown in Figures 2 to 6, both the first reduction section 111 and the second reduction section 112 have a negative slope in the function, and the slope of the heating amount control profile 100 (100A to 100E) at any temperature in the second region 111B is more negative than the slope of the heating amount control profile 100 (100A to 100E) at any temperature in the first region 111A. This allows the target temperature to be reached earlier and reduces temperature fluctuations relative to the target temperature. For example, as shown in Figure 9, profile 202, in which the slope in the first reduction section 111 is always constant, and as shown in Figure 10, profile 203, in which the negative magnitude of the slope at any temperature in the second region 111B is smaller than the negative magnitude of the slope at any temperature in the first region 111A, are excluded from the heating amount control profile 100. In profiles 202 and 203, as shown in Figures 9 and 10, the heating rate is slow, and the target temperature cannot be reached earlier.

[0046] In the heating cycle device according to this embodiment, as shown in Figures 2 to 6, the heating amount control profile 100 (100A to 100E) includes a configuration in which a constant portion 120 exists on the lower temperature side than the first reduction portion 111, in which the heating amount E remains constant even when the temperature T rises from the low temperature side to the high temperature side.

[0047] In the heating cycle device according to this embodiment, as shown in Figures 2 to 6, the second reduction unit 112 preferably has a heat dissipation corresponding region 112A that maintains the heating amount E at a predetermined heating amount on the side of a temperature higher than the target temperature Tt. The heat dissipation corresponding region 112A is a region that brings the heating amount E closer to zero but does not make it zero. It is more preferable that Te at the end of the heat dissipation corresponding region 112A is {target temperature Tt + 8℃} ± 1℃. It is preferable that T2 at the start of the heat dissipation corresponding region 112A is, for example, {target temperature Tt + 4℃} ± 1℃. The radiator 7 is dissipating heat, and if the heating amount is suddenly set to "zero" just because the temperature has risen and exceeded the target temperature Tt, the coolant temperature T will fall below the target temperature, leading to temperature hunting. By providing the heat dissipation corresponding region 112A, temperature hunting can be suppressed.

[0048] In the heating amount control profile 100 (100A to 100E), the temperature T at which the heating amount E becomes 0 is preferably 90°C. If the temperature exceeds 90°C, problems may occur, such as unintended precipitation of components dissolved in the coolant or a decrease in heat conduction due to the generation of bubbles at the interface between the coolant and the heat transfer wire.

[0049] Next, we will explain in more detail examples of each heating amount control profile 100 (100A~100E).

[0050] Figure 2 shows a first example of a heating amount control profile. In the heating cycle device according to this embodiment, as shown in Figure 2, the reduction section 110 is a curve having an inflection point P, and the temperature T at which the inflection point P occurs includes a form in which it coincides with the target temperature Tt. The first example of the heating amount control profile 100 (100A) can reach the target temperature Tt within, for example, 15 minutes, and control the temperature relative to the target temperature Tt to, for example, within the range of {target temperature Tt} ± 1℃. Furthermore, since the temperature T at which the inflection point P occurs coincides with the target temperature Tt, the temperature fluctuation relative to the target temperature Tt can be controlled to be smaller.

[0051] Figure 3 shows a second example of a heating amount control profile. In the heating cycle device according to this embodiment, as shown in Figure 3, the reduction section 110 is a curve having an inflection point P, and the temperature T at which the inflection point P occurs includes a form that is higher than the target temperature Tt. Preferably, the temperature T at which the inflection point P occurs is greater than {target temperature Tt} + 0 degrees and less than or equal to + 4 degrees, and more preferably between {target temperature Tt} + 1 degree and + 2 degrees. If the temperature T at which the inflection point P occurs exceeds {target temperature Tt} + 4 degrees, the coolant may be overheated relative to the target temperature. The heating amount control profile 100 (100B) of the second example can reach the target temperature Tt within, for example, 15 minutes, and control the temperature relative to the target temperature Tt to, for example, within the range of {target temperature Tt} ± 1 degree. Furthermore, since the temperature T at the inflection point P is higher than the target temperature Tt, it becomes easier to set the amount of heating E by the heater to be relatively large when the coolant temperature T is at the target temperature Tt. In particular, in vehicle air conditioning systems 900 where the amount of heat dissipated by the heat sink 7 is relatively large, it is possible to control the temperature fluctuation with respect to the target temperature Tt to be small.

[0052] Figure 4 shows a third example of a heating amount control profile. In the heating cycle device according to this embodiment, as shown in Figure 4, the reduction section 110 is a curve having an inflection point P, the temperature T at which the inflection point P occurs is lower than the target temperature Tt, and the second region 111B includes a configuration that is in the region on the lower temperature side of the inflection point P. The temperature T at which the inflection point P occurs is preferably between {target temperature Tt} - 4°C and less than 0°C, and more preferably between {target temperature Tt} - 1°C and -2°C. If the temperature T at which the inflection point P occurs is less than {target temperature Tt} - 4°C, the time required to reach the target temperature Tt may be longer. In the third example of the heating amount control profile 100 (100C), the first reduction section 111 includes a third region 111C, which is in the region on the higher temperature side of the temperature at which the inflection point P occurs. The third example of the heating amount control profile 100 (100C) can reach the target temperature Tt within, for example, 15 minutes, and control the temperature relative to the target temperature Tt to, for example, within the range of {target temperature Tt} ± 1°C. Furthermore, since the temperature T at the inflection point P is lower than the target temperature Tt, it becomes easy to set the amount of heating E by the heater to be relatively small when the coolant temperature T is at the target temperature Tt. In particular, in a vehicle air conditioning system 900 where the amount of heat dissipated by the radiator 7 is relatively small, it is possible to control the temperature fluctuation relative to the target temperature Tt to be small.

[0053] Figure 5 shows a fourth example of a heating amount control profile. In the heating cycle device according to this embodiment, as shown in Figure 5, both the first region 111A and the second region 111B include a form in which the function is a linear function with different slopes from each other. The heating amount control profile 100 (100D) of the fourth example can reach the target temperature Tt within, for example, 15 minutes, and control the temperature relative to the target temperature Tt to, for example, within the range of {target temperature Tt} ± 1°C.

[0054] Figure 6 shows a fifth example of a heating amount control profile. In the heating cycle device according to this embodiment, as shown in Figure 6, the reduction portion 110 includes a form in which there is no inflection point. The fifth example of the heating amount control profile 100 (100E) can reach the target temperature Tt within, for example, 15 minutes, and control the temperature relative to the target temperature Tt to, for example, within the range of {target temperature Tt} ± 1°C.

[0055] Figure 11 shows an example of duty cycle control for a heating cycle device, where (a) shows duty cycle control in a constant section, (b) shows duty cycle control at an arbitrary temperature in a decreasing section, and (c) shows duty cycle control at an arbitrary temperature in the heat dissipation range. The duty cycle ratio in the decreasing section 110 (shown in Figures 2 to 6) is made smaller than the duty cycle ratio in the constant section 120 (shown in Figures 2 to 6). In the decreasing section 110, the amount of heating E by the heater 4 is adjusted by gradually decreasing the duty cycle ratio over time, as shown in Figures 2 to 6. Alternatively, in the decreasing section 110, the amount of heating E by the heater 4 is adjusted by gradually decreasing the duty cycle ratio as the coolant temperature rises, as shown in Figures 2 to 6.

[0056] The duty cycle period is not particularly limited, but is preferably 0.015 to 0.025 seconds. In Figures 11(a) to (c), the duty cycle period is set to 0.02 seconds as an example. The duty cycle in the constant section 120 (shown in Figures 2 to 6) is not particularly limited, but is preferably 60% to 100%. In Figure 11(a), the duty cycle in the constant section 120 (shown in Figures 2 to 6) is set to 80% as an example. The duty cycle at any temperature in the decreasing section 110 (shown in Figures 2 to 6) is not particularly limited, but is preferably 30% to less than 60%. In Figure 11(b), the duty cycle at the target temperature Tt (shown in Figure 2) is set to 50% as an example. The duty cycle at any temperature in the heat dissipation range is not particularly limited, but is preferably greater than 0% and less than 30%. In Figure 11(c), the duty cycle is set to 20% at an arbitrary temperature within the heat dissipation range as an example.

[0057] In the heating amount control profiles shown in Figures 2 to 4, the heating amount at the inflection point P is preferably 70% or less, and more preferably 60% or less, of the heating amount in the constant section 120. If the heating amount at the inflection point P exceeds 70% of the heating amount in the constant section 120, heating will continue unnecessarily even after the coolant temperature has risen and exceeded the target temperature Tt, making it difficult to control the coolant temperature T to approximate the target temperature Tt. The lower limit of the heating amount at the inflection point P is not particularly limited, but it is preferably 30% or more, and more preferably 40% or more, of the heating amount in the constant section 120. If the heating amount at the inflection point P is less than 30% of the heating amount in the constant section 120, the heating amount may be insufficient when the coolant temperature approaches the target temperature Tt, and the time it takes for the coolant temperature to reach the target temperature Tt may be prolonged.

[0058] As shown in Figure 1, the vehicle air conditioning system 900 according to this embodiment includes a heating cycle device 1 according to this embodiment and is mounted on a vehicle, the vehicle being capable of being driven by an electric motor, and the vehicle air conditioning system 900 has a temperature control unit 901 that adjusts the temperature of the air supplied to the passenger compartment, and the radiator 7 is a hot water type heat exchanger located inside the temperature control unit 901.

[0059] The vehicle air conditioning system 900 includes a blower unit 904 and a temperature control unit 901. The blower unit 904 is equipped with a fan 902 that blows air taken in from an internal air inlet and / or an external air inlet (not shown) toward an air passage 903. The internal space of the temperature control unit 901 is an air passage 903, and a hot water heat exchanger (radiator) 7 is arranged in the air passage 903. It is preferable that the hot water heat exchanger 7 further includes a cooling heat exchanger (not shown) upstream of the air passage 903, which dehumidifies and cools the air sent from the blower unit 904 as needed, and an air mix door (not shown) positioned between the cooling heat exchanger and the hot water heat exchanger 7 to adjust the ratio of air passing through the hot water heat exchanger 7 to air bypassing the hot water heat exchanger 7. The downstream end of the temperature control unit 901 is provided with a defrost opening (not shown), a vent opening (not shown), and a foot opening (not shown). Each opening is connected indirectly or directly to an air outlet (not shown) inside the vehicle cabin via a duct (not shown).

[0060] Vehicles include, for example, electric vehicles (EVs) that run solely on electric motors, hybrid electric vehicles (HEVs) that run on multiple power sources including electric motors and internal combustion engines, or vehicles in which the internal combustion engine only generates electricity and the vehicle runs on an electric motor driven by that electricity. In these vehicles, the total amount of coolant in the coolant loop tends to be less than in vehicles with engines, and if temperature hunting occurs at the outlet point of the fluid heating unit, the hunting effect is likely to spread throughout the entire path. However, the heating cycle device 1 installed in the vehicle air conditioning system according to this embodiment can control the temperature hunting to a small extent. If the coolant temperature hunts, when the vehicle air conditioning system 900 is operating in full hot mode, the temperature of the warm air blown out from the vents in the passenger compartment may hunt, potentially impairing comfort. Alternatively, when the vehicle air conditioning system 900 is operating in temperature control mode, it may be necessary to frequently adjust the position of the air mix door to keep the temperature of the blown-out warm air constant, and the operating noise emitted by the actuator that drives the air mix door may impair comfort.

[0061] Although not shown in the diagram, it is preferable to detect the airflow rate of the blower 902, the temperature of the air upstream of the radiator 7, and the temperature of the conditioned air downstream of the air mix door, input them to the heating control device 6, estimate the amount of heat dissipated by the radiator 7, and change the heating amount at the inflection point P in Figures 2 to 4 according to the amount of heat dissipated by the radiator 7. Specifically, when the amount of heat dissipated by the radiator 7 is relatively large, the inflection point P is adjusted to a value with a larger heating amount, and when the amount of heat dissipated by the radiator 7 is relatively small, the inflection point P is adjusted to a value with a smaller heating amount. When the amount of heat dissipated by the heat dissipation amount 7 is large, the coolant temperature T can be brought to the target temperature Tt earlier. When the amount of heat dissipated by the radiator 7 is small, it is possible to reliably prevent the coolant temperature T from rising further after reaching the target temperature Tt, and to control the coolant temperature T to approximate the target temperature Tt. [Examples]

[0062] The present invention will be described in more detail below based on examples, but the present invention is not limited in any way to such examples.

[0063] (Example 1) The heating control device controlled the switching operation of the transistor based on the heating amount control profile shown in Figure 2, and adjusted the amount of heating by the heater by changing the on-off duty cycle of the transistor. The target temperature was set to 80°C. Figure 12 is a diagram showing the relationship between heating time and coolant temperature in Example 1. In Figure 12, the region denoted by reference numeral 301 corresponds to the constant portion 120 in Figure 2, the region denoted by reference numeral 302 corresponds to the first decreasing portion 111, and the region denoted by reference numeral 303 corresponds to the second decreasing portion 112.

[0064] (Comparative Example 1) Except for changing the heating amount control profile to the profile shown in Figure 7, the amount of heating by the heater was adjusted in the same manner as in Example 1. The target temperature was set to 80°C. Figure 13 shows the relationship between heating time and coolant temperature in Comparative Example 1.

[0065] (Comparative Example 2) Except for changing the heating amount profile to the profile shown in Figure 9, the amount of heating by the heater was adjusted in the same manner as in Example 1. The target temperature was set to 80°C. Figure 14 shows the relationship between heating time and coolant temperature in Comparative Example 2.

[0066] As shown in Figure 12, Example 1 reached the target temperature in less than 15 minutes, demonstrating that the target temperature could be reached in a short time. Furthermore, the temperature fluctuation relative to the target temperature was within ±1°C, indicating that the temperature fluctuation was controlled to a small extent. In contrast, as shown in Figure 13, Comparative Example 1 also reached the target temperature in less than 15 minutes, but the temperature fluctuation relative to the target temperature was ±5°C, indicating a large temperature fluctuation. As shown in Figure 14, Comparative Example 2's temperature fluctuation relative to the target temperature was within ±1°C, but the time to reach the target temperature exceeded 20 minutes, indicating a long time to reach the target temperature. [Explanation of Symbols]

[0067] 1 Heating cycle device 2 Circulation channel 3 pumps 4 Heaters 5 transistors 6. Heating control device 7 Heatsink 8 batteries 10 Fluid heating unit 10a Outlet 10b Inlet 11, 12, 13 Piping 50 Temperature Sensors 100 (100A~100E) Heating Amount Control Profile 110 Decreasing part 111 1st reduction part 112 2nd reduction part 111A 1st area 111B 2nd area 111C 3rd area 112A Heat dissipation capacity range Profiles 200, 201, 202, 203 900 Vehicle air conditioning system 901 Temperature Control Unit 902 Blower 903 Airflow channel 904 Blower Unit P inflection point

Claims

1. In a heating control device (6) that controls a transistor (5) that supplies power by switching operation to a heater (4) that heats the coolant supplied to a heat sink (7) mounted on a vehicle air conditioning system by generating heat when energized, The heating control device (6) controls the switching operation of the transistor (5) based on the heating amount control profile (100 (100A to 100E)), and adjusts the amount of heating by the heater (4) by changing the on-off duty cycle of the transistor (5). The heating amount control profile (100 (100A to 100E)) is a function that shows the relationship between the temperature (T) of the coolant and the amount of heating (E) by the heater (4), and has a decreasing portion (110) in which the amount of heating (E) decreases as the temperature (T) rises from the low temperature side to the high temperature side across the target temperature (Tt) of the coolant. The reducing portion (110) has a first reducing portion (111) when the temperature (T) is in a temperature range of less than or equal to the target temperature (Tt), and a second reducing portion (112) when the temperature (T) is in a temperature range of greater than or equal to the target temperature (Tt), and the first reducing portion (111) and the second reducing portion (112) have the same amount of heating (E) at the target temperature (Tt). The first decreasing portion (111) and the second decreasing portion (112) both have a negative slope in the function, The first reduction portion (111) has a first region (111A) and a second region (111B) that is at a higher temperature than the first region (111A). A heating control device characterized in that the slope of the heating amount control profile (100 (100A to 100E)) at any temperature within the second region (111B) has a larger negative slope than the slope of the heating amount control profile (100 (100A to 100E)) at any temperature within the first region (111A).

2. The aforementioned reduction portion (110) is a curve having an inflection point (P), The heating control device according to claim 1, characterized in that the temperature (T) at the inflection point (P) coincides with the target temperature (Tt).

3. The aforementioned reduction portion (110) is a curve having an inflection point (P), The heating control device according to claim 1, characterized in that the temperature (T) at the inflection point (P) is higher than the target temperature (Tt).

4. The aforementioned reduction portion (110) is a curve having an inflection point (P), The temperature (T) at which the inflection point (P) occurs is lower than the target temperature (Tt). The heating control device according to claim 1, characterized in that the second region (111B) is located in a region on the lower temperature side than the inflection point (P).

5. The heating control device according to claim 1, characterized in that the first region (111A) and the second region (111B) are both linear functions with different slopes in the function.

6. The heating control device according to claim 1, characterized in that the reduction portion (110) is a curve that does not have an inflection point (P).

7. The heating control device according to claim 1, characterized in that the heating amount control profile (100 (100A to 100E)) has a constant portion (120) on the lower temperature side than the first reduction portion (111) in which the heating amount (E) remains constant even when the temperature (T) rises from the low temperature side to the high temperature side.

8. The heating control device according to claim 1, characterized in that the second reduction section (112) has a heat dissipation corresponding region (112A) that maintains the heating amount (E) at a predetermined heating amount on the side of the target temperature (Tt).

9. The heating control device (6) comprises a heater (4) that generates heat when an electric current is applied to heat the coolant, a transistor (5) that supplies power to the heater (4) by switching operation, and a heating control device (6) according to any one of claims 1 to 8. The heating control device (6) is characterized by controlling the switching operation of the transistor (5) in the fluid heating unit (10).

10. The device comprises a circulation channel (2), a coolant filled in the circulation channel (2), a pump (3) for circulating the coolant in the circulation channel (2), a fluid heating unit (10) according to claim 9 for controlling the temperature of the coolant, and a heat sink (7) for dissipating heat from the coolant. The heating cycle device is characterized in that the coolant is heated in the fluid heating unit (10) by the heater (4) being energized by the transistor (5).

11. A vehicle air conditioning system (900) mounted on a vehicle, comprising a heating cycle device (1) as described in claim 10, The aforementioned vehicle is capable of being driven by an electric motor. The vehicle air conditioning system (900) includes a temperature control unit (901) that adjusts the temperature of the air supplied to the vehicle interior. The vehicle air conditioning system is characterized in that the heat exchanger (7) is a hot water type heat exchanger located inside the temperature control unit (901).

12. A control program characterized in that it causes the heating control device (6) according to any one of claims 1 to 8 to execute a process that controls the switching operation of the transistor (5) based on the heating amount control profile (100 (100A to 100E)).

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