Control device

Abstract

To properly cope with freezing occurring in a contact point of a relay.SOLUTION: A processor of a controller executes the steps of: determining whether freezing generation condition that is a condition where freezing occurs at a contact point of a relay after stopping a driving source of a vehicle is satisfied or not based on at least one of the condition of heat source of the vehicle and ambient temperature; and intermittently and repeatedly performing, when the freezing generation condition is satisfied, an ice crushing operation where a movable contact hits a fixed contact through turning on the relay in an off state and then turning off it in a specified time interval during a specified ice crushing period after turning off the relay corresponding to operation stop of the driving source. The specified ice crushing period is set according to the difference between temperature of the contact point of the relay and the temperature of internal atmosphere of the relay. The specified time interval is time period until the ice on the contact point of the relay grows to a specified size.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a control device for controlling a relay.

Background Art

[0002] For example, a vehicle is equipped with a relay for turning on and off an electrical connection between a power source and an electrical load. In a low-temperature environment, after the relay is turned off in response to the stop of the vehicle's drive source, if a predetermined condition is satisfied, icing may occur at the relay contacts. When such icing occurs, when the relay is turned on at the subsequent start of the vehicle, the contacts may be insulated by the icing, and there is a risk that the contacts cannot be energized properly. For example, Patent Document 1 discloses a technique in which, after a stop signal for stopping the vehicle's drive is input, a PWM-modulated voltage is applied to the relay's excitation coil for a predetermined time. In such a technique, a voltage PWM-modulated at a duty ratio such that the energization of the relay contacts is maintained is applied to the excitation coil. In such a technique, by maintaining the energization of the relay contacts, heat generation at the contacts continues, and the occurrence of icing can be suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, although the relay is turned off after the energization of the contacts is maintained, depending on the conditions after the off state, there is a risk of icing. And when such icing occurs, when the relay is turned on at the subsequent start of the vehicle, the contacts may be insulated by the icing, and there is a risk that the contacts cannot be energized properly.

[0005] Therefore, an object of the present invention is to provide a control device that appropriately addresses icing occurring at the contacts of a relay.

Means for Solving the Problems

[0006] To solve the above problems, a control device according to an embodiment of the present invention is a control device that is mounted on a vehicle and controls a relay having a fixed contact and a movable contact, including one or more processors, and one or more memories connected to the processor, and the processor determines whether or not an icing occurrence condition, which is a condition under which icing may occur at the contacts of the relay, is satisfied after the operation of the drive source of the vehicle stops, based on at least one of the state of the heat source of the vehicle and the outside air temperature; when the icing occurrence condition is satisfied, in a predetermined ice-breaking period after the relay is turned off in response to the stop of the operation of the drive source, an ice-breaking operation of hitting the fixed contact with the movable contact by turning on and then turning off the relay in the off state is intermittently repeated at a predetermined time interval; and executes a process including this, the predetermined ice-breaking period is set according to the temperature difference between the temperature of the contacts of the relay and the temperature of the internal atmosphere of the relay, and the predetermined time interval is the time until the ice formed on the contacts of the relay grows to a predetermined size.

Advantages of the Invention

[0007] According to the present invention, it becomes possible to appropriately address icing occurring at the contacts of a relay.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The specific dimensions, materials, numerical values, etc. shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals, and redundant explanations are omitted, and elements not directly related to the present invention are not shown.

[0010] FIG. 1 is a schematic view showing a vehicle 1 provided with a relay 10 according to the present embodiment. The vehicle 1 is an engine vehicle provided with an engine 4 as a driving source for traveling. Note that the vehicle 1 may be a hybrid vehicle provided with an engine and a motor as driving sources for traveling, or an electric vehicle provided with a motor as a driving source for traveling.

[0011] At the front of the vehicle 1, an engine room 3 is provided inside the bonnet 2. Inside the engine room 3, various devices such as a drive device, a cooling device, an air conditioning device, a power source, a control device, and sensors are installed. For example, inside the engine room 3, an engine 4, a radiator 5, a transmission (not shown), etc. are installed. Further, inside the engine room 3, a relay box 8 for housing the relay 10 is also installed. In the example of FIG. 1, the relay box 8 is arranged on the upper side of the left rear in the engine room 3, but it may be installed at other locations in the engine room 3. By installing the relay 10 inside the relay box 8, it is possible to prevent moisture, dust, etc. from entering the relay.

[0012] The relay 10 is, for example, a main relay connected between a control device 12 which is an example of an electrical load and a power source 7. The relay 10 is a switching device that switches on and off (supplies and cuts off power) the power supply from the power source 7 to the control device 12. The relay 10 is used, for example, to turn on or off the supply of power necessary for controlling various devices such as the engine 4 or the transmission.

[0013] The control device 12 is, for example, an electronic control unit (ECU) that controls the air-fuel ratio, ignition timing, electronically controlled throttle valve, etc. of the engine 4. Note that the control device 12 may be a transmission control unit (TCU) that controls the transmission, or a control device that controls other various in-vehicle devices.

[0014] The relay 10 is not limited to the mode of being connected between the control device 12 and the power source 7. For example, the relay 10 may be connected between another electrical load other than the control device 12 and the power source 7. The electrical load may be, for example, a drive device such as a vehicle drive motor or other motors, or various in-vehicle electrical components that require power, such as auxiliary machines, cooling devices, air conditioning devices, sensors, car navigation devices, display devices, audio devices, electric slide doors, etc. That is, the relay 10 is not limited to the main relay and may be various relays.

[0015] The power source 7 is a battery that stores electric power to supply to an electric load. The power source 7 is composed of a battery mounted on the vehicle 1, for example, an auxiliary battery. However, the power source 7 is not limited to such an example, and may be various batteries mounted on the vehicle 1 such as a high-voltage battery for a drive motor of a hybrid vehicle or an electric vehicle, or an external power source.

[0016] FIG. 2 is a longitudinal sectional view showing an example of the configuration of the relay 10 mounted on the vehicle 1 according to the present embodiment. As shown in FIG. 2, the relay 10 is composed of a mechanical relay such as an electromagnetic relay. A mechanical relay is a relay having contacts that mechanically approach or separate. Note that the specific structure of the relay 10 is not limited to the structure illustrated in FIG. 2, and may be any structure that constitutes a mechanical relay.

[0017] The relay 10 has a case 20, a fixed contact 22, a movable contact 24, a biasing member 26, and an exciting coil 28. The case 20 is formed in a hollow box shape of an insulator such as synthetic resin, for example. The fixed contact 22, the movable contact 24, the biasing member 26, and the exciting coil 28 are housed in the case 20. Note that the fixed contact 22 and the movable contact 24 may be collectively referred to simply as the contact 21.

[0018] The fixed contact 22 is supported by the case 20 via a fixed-side base portion 30 and is fixedly installed in the case 20. The fixed contact 22 is formed in a columnar shape, for example. The fixed-side base portion 30 extends in the vertical direction from the inner surface of the bottom of the case 20. A first end portion in the central axis direction of the fixed contact 22 is connected to the tip end portion of the fixed-side base portion 30. The surface of the second end portion on the opposite side of the fixed-side base portion 30 in the central axis direction of the fixed contact 22 is formed in a planar shape.

[0019] At the base end of the fixed-side base portion 30, a fixed-side terminal 32 protruding outside the case 20 is connected. The fixed contact 22, the fixed-side base portion 30, and the fixed-side terminal 32 are formed of a conductive material, for example, a metal material such as copper, iron, or phosphor bronze. The fixed contact 22, the fixed-side base portion 30, and the fixed-side terminal 32 may be integrally formed of one metal part, or may be formed by combining a plurality of parts. The fixed contact 22 is electrically connected to the fixed-side terminal 32 through the fixed-side base portion 30.

[0020] The movable contact 24 is supported by the case 20 via the movable-side base portion 40, the movable portion 42, and the extending portion 44, and is movably installed within the case 20. The movable contact 24 is formed, for example, in a columnar shape. The movable-side base portion 40 extends in the vertical direction from the inner surface of the bottom of the case 20. At the tip of the movable-side base portion 40, a movable portion 42 extending so as to approach the fixed contact 22 from the movable-side base portion 40 is connected. The movable portion 42 is swingable with the connecting portion with the movable-side base portion 40 as a fulcrum. The movable portion 42 is formed of a magnetic material such as iron, for example. At the tip of the movable portion 42, an extending portion 44 extending the movable portion 42 is connected. At the surface on the bottom side of the case 20 in the extending portion 44, the first end in the central axis direction of the movable contact 24 is connected. The surface of the second end on the opposite side of the extending portion 44 in the central axis direction of the movable contact 24 is formed in a planar shape.

[0021] The case 20 is provided with a movable-side terminal 46 protruding outside the case 20. The movable contact 24, the extending portion 44, and the movable-side terminal 46 are formed of a conductive material, for example, a metal material such as copper, iron, or phosphor bronze. The movable contact 24 and the extending portion 44 may be integrally formed of one metal part, or may be formed by combining a plurality of parts. The movable-side terminal 46 is electrically connected to the extending portion 44 by, for example, an electric wire. The movable contact 24 is electrically connected to the movable-side terminal 46 through the extending portion 44 and an electric wire or the like.

[0022] The movable contact 24 is arranged to face the fixed contact 22. Since the movable contact 24 is supported by the movable part 42 via the extension part 44, it swings according to the swing of the movable part 42. The movable contact 24 can move in a direction approaching or separating from the fixed contact 22 according to the swing of the movable part 42. When the movable contact 24 is separated from the fixed contact 22, the movable contact 24 and the fixed contact 22 are electrically disconnected. When the movable contact 24 moves in a direction approaching the fixed contact 22, the surface of the movable contact 24 contacts the surface of the fixed contact 22. When the movable contact 24 contacts the fixed contact 22, the movable contact 24 and the fixed contact 22 are electrically connected. Hereinafter, the movement of the movable contact 24 in a direction approaching the fixed contact 22 may be referred to as turning on the relay 10, and the movement of the movable contact 24 in a direction separating from the fixed contact 22 may be referred to as turning off the relay 10.

[0023] The biasing member 26 is, for example, a spring or the like, but may be a leaf spring or rubber or the like. The biasing member 26 is provided, for example, between the movable part 42 and the case 20, but may be provided between the movable part 42 and the movable-side base part 40. The biasing member 26 biases the movable contact 24 in a direction separating it from the fixed contact 22.

[0024] A columnar iron core 50 extending in the vertical direction is installed at the bottom of the case 20. The iron core 50 is arranged below the movable part 42. The exciting coil 28 is wound around the iron core 50.

[0025] The case 20 is provided with a first exciting terminal 52 and a second exciting terminal 54 protruding outside the case 20. The first exciting terminal 52 and the second exciting terminal 54 are formed of a conductive material, for example, a metal material such as copper, iron, or phosphor bronze. Each of the first exciting terminal 52 and the second exciting terminal 54 is electrically connected to the exciting coil 28.

[0026] Current flows through the excitation coil 28 via the first excitation terminal 52 and the second excitation terminal 54. When current flows through the excitation coil 28, it functions as an electromagnet. The iron core 50 is provided to enhance the effect of the electromagnet.

[0027] When no current is flowing through the excitation coil 28, the movable part 42 is biased by the biasing member 26 in a direction away from the fixed contact 22. In this case, the movable contact 24 is separated from the fixed contact 22 and insulated from the fixed contact 22. That is, the relay 10 is in the off state.

[0028] On the other hand, when current flows through the excitation coil 28, the excitation coil 28 functions as an electromagnet, and the excitation coil 28 attracts the movable part 42. The movable part 42 moves in a direction closer to the excitation coil 28, overcoming the biasing force of the biasing member 26 due to the magnetic force of the excitation coil 28. In this case, the movable contact 24 moves in a direction closer to the fixed contact 22 together with the movable part 42 and comes into contact with the fixed contact 22. That is, the relay 10 turns on. The relay 10 maintains the on state while the current flowing through the excitation coil 28 generates a magnetic force in the excitation coil 28 that overcomes the biasing force of the biasing member 26.

[0029] When the current stops flowing through the excitation coil 28, the excitation coil 28 no longer generates a magnetic force, so the attraction of the movable part 42 by the excitation coil 28 stops. As a result, the movable part 42 and the movable contact 24 move in a direction away from the fixed contact 22 due to the biasing force of the biasing member 26. That is, the relay 10 turns off. In this way, the relay 10 turns on and off by moving the movable contact 24 in a direction closer to or away from the fixed contact 22.

[0030] FIG. 3 is a block diagram showing an example of the connection configuration of the relay 10 and the control device 12 according to the present embodiment. The control device 12 includes one or more processors 60 and one or more memories 62 connected to the processor 60. The memory 62 includes a ROM in which programs and the like are stored, and a RAM as a work area. The processor 60 of the control device 12 cooperates with the programs included in the memory 62 to control the entire vehicle 1. For example, the processor 60 controls the engine 4. The processor 60 also functions as a relay control unit 64 that controls the relay 10. The relay control unit 64 will be described in detail later.

[0031] In the example of FIG. 3, the power supply 7 is electrically connected to the movable-side terminal 46 of the relay 10 and supplies power to the movable contact 24. The fixed-side terminal 32 of the relay 10 is electrically connected to various electrical components 70 that are controlled by the control device 12 via the control device 12. The electrical component 70 is, for example, an electronic control throttle, but is not limited to this example and may be any electrical component. The power supply 7 supplies power to the electrical component 70 when the relay 10 is turned on. In the example of FIG. 3, an example in which the power supply 7 is connected to the movable-side terminal 46 is shown, but the power supply 7 may be connected to the fixed-side terminal 32 side. In that case, the electrical component 70 is connected to the movable-side terminal 46 side via the control device 12.

[0032] The control device 12 includes a control switch 71. The control switch 71 is, for example, a semiconductor switch. The control switch 71 is electrically connected between the relay 10 and the electrical component 70. For example, the first terminal of the control switch 71 is connected to the fixed-side terminal 32 and is electrically connected to the power supply 7 via the relay 10. The second terminal of the control switch 71 is connected to the first terminal 70a of the electrical component 70. The second terminal 70b of the electrical component 70 is grounded. Note that the control switch 71 is not limited to the example of being connected to the first terminal 70a side of the electrical component 70, and the control switch 71 may be connected to the second terminal 70b side of the electrical component 70. The processor 60 controls the on / off of the control switch 71 by controlling the current or voltage of the control terminal of the control switch 71, which is, for example, a semiconductor switch. When the relay 10 and the control switch 71 are turned on, the power supply 7 supplies power to the electrical component 70.

[0033] The control device 12 includes a capacitor 72. The first electrode of the capacitor 72 is connected to the fixed-side terminal 32 of the relay 10 and is also connected to the electrical component 70 via the control switch 71. The second electrode of the capacitor 72 is grounded. The capacitor 72 smoothes the power supplied to the electrical component 70 or the control device 12.

[0034] Also, the power supply 7 is electrically connected to the processor 60 and supplies power to the processor 60 as well.

[0035] The control device 12 includes an excitation switch 74. The excitation switch 74 is, for example, a semiconductor switch. The excitation switch 74 is electrically connected between the excitation coil 28 and the power source 7. For example, the first terminal of the excitation switch 74 is connected to the power source 7, and the second terminal of the excitation switch 74 is connected to the first excitation terminal 52. The second excitation terminal 54 is grounded. Note that the excitation switch 74 is not limited to the example of being connected to the first excitation terminal 52 side, and the excitation switch 74 may be connected to the second excitation terminal 54 side. The processor 60 controls the on / off of the excitation switch 74 by controlling the current or voltage of the control terminal of the excitation switch 74, which is, for example, a semiconductor switch. When the excitation switch 74 is turned on, the power source 7 supplies power to the excitation coil 28.

[0036] The vehicle 1 includes an outside air temperature sensor 80, a water temperature sensor 82, and an ignition switch 84. The outside air temperature sensor 80 detects the outside air temperature outside the vehicle 1, that is, the outside air temperature outside the vehicle. The water temperature sensor 82 detects the temperature of the cooling water that cools the engine 4. By detecting the temperature of the cooling water, the water temperature sensor 82 indirectly detects the temperature of the engine 4, which is the drive source. That is, the water temperature sensor 82 functions as a drive source temperature sensor that detects the temperature of the drive source.

[0037] The ignition switch 84 receives an ignition on (IG-ON) or ignition off (IG-OFF) operation by the occupant. When the ignition switch 84 receives an IG-ON operation, it transmits a start signal for starting the engine 4, which is the drive source, to the control device 12. When the relay control unit 64 acquires the start signal due to IG-ON from the ignition switch 84, it turns on the relay 10 to start the engine 4. Further, when the ignition switch 84 receives an IG-OFF operation, it transmits a stop signal for stopping the engine 4, which is the drive source, to the control device 12. When the relay control unit 64 acquires the stop signal due to IG-OFF from the ignition switch 84, after stopping the engine 4, it turns off the relay 10.

[0038] After turning off relay 10 in response to the stop of engine 4, if relay 10 meets a predetermined temperature condition, icing may occur at contact point 21 of relay 10. When such icing occurs, when relay 10 is turned on at the start of vehicle 1 thereafter, the icing may insulate contact point 21, making it impossible to properly energize contact point 21.

[0039] Therefore, under conditions where icing may occur, relay control unit 64 intentionally turns relay 10 on and off to strike fixed contact 22 with movable contact 24, thereby crushing the icing on contact point 21. Hereinafter, crushing the icing may be referred to as ice crushing. Below, the conditions under which icing occurs will be described, and then the control related to ice crushing by relay control unit 64 will be described.

[0040] FIG. 4 is a diagram for explaining the occurrence of icing and the operation of the relay control unit 64 according to the present embodiment. Among the four time charts shown in FIG. 4, the solid line A10 in the second time chart from the top is an example of the temporal change in the temperature Tc of the contact 21 of the relay 10. More specifically, considering that the temperature of the fixed contact 22 is more likely to decrease than the temperature of the movable contact 24, the temperature Tc is assumed to be the temperature of the fixed contact 22, but it may also be the temperature of the movable contact 24. Also, the dashed-dotted line A11 in the second time chart shows an example of the temporal change in the temperature Tin of the internal atmosphere of the relay 10. Also, as shown by the two-dot chain line A12, the first time chart from the top shows the temperature difference ΔT (ΔT = Tin - Tc) obtained by subtracting the temperature Tc of the contact 21 of the relay 10 from the temperature Tin of the internal atmosphere of the relay 10. More specifically, the temperature difference ΔT is assumed to be obtained by subtracting the temperature of the fixed contact 22 of the relay 10 from the temperature Tin of the internal atmosphere of the relay 10, but it may also be obtained by subtracting the temperature of the movable contact 24 of the relay 10 from the temperature Tin of the internal atmosphere of the relay 10. Also, the third time chart from the top shows an example of the state of the contact 21 of the relay 10. Also, the fourth time chart from the top shows an example of the state of the processor 60 functioning as the relay control unit 64. Each of the first to fourth time charts has a common time axis. Hereinafter, the temperature Tc of the contact 21 of the relay 10 may be simply referred to as the temperature Tc of the contact 21, and the temperature Tin of the internal atmosphere of the relay 10 may be simply referred to as the temperature Tin of the internal atmosphere.

[0041] In the example of FIG. 4, it is assumed that at time point T10, the outside air temperature was below freezing, that is, 0°C or lower. And at time point T10, an IG-ON operation was performed, and the relay control unit 64 turned on the relay 10 in response to the IG-ON operation. Also, at time point T10, the relay control unit 64 started the engine 4 together with turning on the relay 10. At time point T10, both the temperature Tc of the contact 21 and the temperature Tin of the internal atmosphere were below freezing and were approximately the same.

[0042] When the engine 4 starts at time point T10, the engine 4 is warmed up, and the engine room 3 is gradually warmed by the heat generated by the engine 4. Then, the air in the relay box 8 arranged in the engine room 3 is gradually warmed, and the case 20 of the relay 10 arranged in the relay box 8 is gradually warmed. As a result, as shown by the dashed line A11, the temperature Tin of the internal atmosphere, that is, the temperature of the air in the case 20 of the relay 10, gradually rises.

[0043] Also, when the relay 10 is turned on at time point T10, the movable contact 24 and the fixed contact 22 come into contact, and an electric current flows between the contacts 21. When the contacts 21 are energized in this way, the contacts 21 generate heat, and as shown by the solid line A10, the temperature Tc of the contacts 21 rises. At this time, since the contacts 21 are formed of a conductive material, the heat capacity of the contacts 21 is larger than the heat capacity of the air, and the temperature Tc of the contacts 21 shown by the solid line A10 rises earlier than the temperature Tin of the internal atmosphere shown by the dashed line A11. Also, when the vehicle 1 runs after time point T10, the running wind is supplied into the engine room 3, and the case 20 of the relay 10 is cooled by the running wind. The internal atmosphere of the relay 10 is more easily cooled by the running wind than the contacts 21 of the relay 10, and the temperature rise is suppressed. Thus, even if the temperature Tc of the contacts 21 is below the freezing point, as long as the temperature Tc of the contacts 21 is equal to or higher than the temperature Tin of the internal atmosphere, icing does not occur on the contacts 21.

[0044] Here, it is assumed that an IG-OFF operation is performed at time T11. When the relay control unit 64 receives a stop signal due to IG-OFF at time T11, it stops the engine 4. After the engine 4 stops, the relay control unit 64 performs self-diagnosis of each device such as the electrical component 70. In this self-diagnosis, depending on the device to be diagnosed, it is necessary to operate the device. For example, when performing self-diagnosis of the electronic control throttle, the relay control unit 64 operates the electronic control throttle. That is, it is necessary to supply power to the device to be diagnosed. Therefore, after the engine 4 stops, the relay control unit 64 maintains the relay 10 in the ON state for at least the period until the self-diagnosis is completed, and maintains the power supply to the device to be diagnosed. Then, after the self-diagnosis is completed, the relay control unit 64 turns off the relay 10. In the example of FIG. 4, the relay control unit 64 turns off the relay 10 at time T12. Hereinafter, the time from the stop time of the drive source (time T11) to when the relay 10 is turned off may be referred to as the self-shutdown time.

[0045] When the relay 10 is turned off, the contacts 21 are insulated from each other, so the contacts 21 do not generate heat. Further, the fixed contact 22 dissipates heat through the fixed-side terminal 32 exposed to the outside of the relay 10, and the movable contact 24 dissipates heat through the movable-side terminal 46 exposed to the outside of the relay 10. Therefore, as shown by the solid line A10, after time T12, the temperature Tc of the contact 21 decreases.

[0046] On the other hand, since the engine 4 has a large mass and heat capacity, a lot of heat is stored in the engine 4 due to warm-up before time T11. After the engine 4 stops at time T11, the stored heat is gradually dissipated into the engine room 3. As a result, even after time T12 when the relay 10 is turned off, the case 20 of the relay 10 is heated by the heat released from the engine 4. Also, after the engine 4 stops, the case 20 of the relay 10 is not cooled by the running wind. Therefore, as shown by the dashed-dotted line A11, after time T12, the temperature Tin of the internal atmosphere rises.

[0047] Thus, as the temperature Tc of the contact point 21 decreases and the temperature Tin of the internal atmosphere increases, after the time point T12, as indicated by the two-dot chain line A12, the temperature difference ΔT obtained by subtracting the temperature Tc of the contact point 21 from the temperature Tin of the internal atmosphere increases. Then, the temperature Tc of the contact point 21 is below the freezing point, and the temperature Tc of the contact point 21 becomes lower than the temperature Tin of the internal atmosphere. Under this condition, freezing occurs at the contact point 21. More specifically, the water vapor in the air within the relay 10 contacts the contact point 21, which is lower than the temperature of the air within the relay 10, causing the water vapor to reach the saturated water vapor amount and condense on the contact point 21. Then, the water due to the condensation contacts the contact point 21 below the freezing point, resulting in freezing on the contact point 21. Freezing occurs as ice crystal nuclei are formed and water accumulates around the ice crystal nuclei and grows. And the greater the temperature difference ΔT between the temperature Tc of the contact point 21 and the temperature Tin of the internal atmosphere expands, the easier it is for freezing to occur and grow on the contact point 21.

[0048] As described above, after the time point T12, the contact point 21 dissipates heat from the contact point 21. And when the heat dissipation of the contact point 21 is completed, the contact point 21 is heated by the heat released from the engine 4 in the same manner as the case 20 of the relay 10. For this reason, as indicated by the solid line A10, the temperature Tc of the contact point 21 changes from a decrease to an increase. Then, as indicated by the two-dot chain line A12, the increase amount of the temperature difference ΔT decreases. And as time passes, the temperature difference ΔT becomes constant from an increase and then decreases. And as more time passes, finally, the temperature Tc of the contact point 21 and the temperature Tin of the internal atmosphere become approximately the same.

[0049] The period from time point T12 to time point T13 in FIG. 4 is a first period in which the temperature difference ΔT between the temperature Tc of the contact 21 and the temperature Tin of the internal atmosphere increases with the passage of time. The period from time point T13 to time point T14 is a second period in which the temperature difference ΔT between the temperature Tc of the contact 21 and the temperature Tin of the internal atmosphere is substantially constant. After time point T14, it is a third period in which the temperature difference ΔT between the temperature Tc of the contact 21 and the temperature Tin of the internal atmosphere decreases with the passage of time. Although not shown in the figure, the third period is a period until the temperature Tc of the contact 21 and the temperature Tin of the internal atmosphere become substantially the same.

[0050] As described above, the relay control unit 64 stops the engine 4 at time point T11 in response to IG-OFF and turns off the relay 10 at time point T12. At time point T12 when the relay control unit 64 turns off the relay 10, it determines whether or not the ice formation occurrence condition is satisfied based on at least one of the state of the heat source of the vehicle 1 and the outside air temperature.

[0051] Here, the heat source indicates a heat source around the relay 10 that can be a factor in increasing the temperature of the internal atmosphere of the relay 10. Examples of this heat source include the engine 4 which is a drive source. Note that the heat source is not limited to the drive source, and may be various devices arranged around the relay 10 and generating heat, such as an in-vehicle air conditioner. Further, the state of the heat source may include the temperature of the heat source or the state of the presence or absence of the operation of the device that is the heat source.

[0052] The icing occurrence condition is a condition under which icing can occur at the contacts of relay 10. More specifically, the icing occurrence condition is, for example, a temperature condition where the outside air temperature is below freezing and the temperature of the drive source is equal to or higher than a predetermined temperature. For example, the relay control unit 64 acquires the water temperature from the water temperature sensor 82 as the temperature of the drive source and acquires the outside air temperature from the outside air temperature sensor 80. When the outside air temperature acquired from the outside air temperature sensor 80 is below freezing and the water temperature acquired from the water temperature sensor 82 is equal to or higher than the predetermined temperature, the relay control unit 64 determines that the icing occurrence condition is satisfied. The predetermined temperature of the water temperature is set to a temperature that can distinguish, for example, that the engine 4 is sufficiently warmed up, such as 70°C.

[0053] Note that the icing occurrence condition is not limited to a temperature condition where the outside air temperature is below freezing and the temperature of the drive source is equal to or higher than a predetermined temperature. For example, regardless of whether the outside air temperature is below freezing, the fact that a predetermined device serving as a heat source has been started during one driving cycle from IG-ON to IG-OFF may be set as the icing occurrence condition. That is, in this example, at the time point T12 when the relay 10 is turned off in response to IG-OFF, assuming that the heat source has reached a temperature equal to or higher than a predetermined temperature or a predetermined temperature difference has occurred between the outside air temperature and the temperature of the heat source, it may be regarded that icing has occurred. Further, the fact that the outside air temperature is below freezing and a predetermined device serving as a heat source has been started during one driving cycle may be set as the icing occurrence condition. Further, regardless of the state of the heat source such as the temperature of the heat source or the start history of the heat source, only the fact that the outside air temperature is below freezing may be set as the icing occurrence condition. Thus, the icing occurrence condition may be set using an index of at least one of the state of the heat source and the outside air temperature.

[0054] Here, when it is determined that the icing occurrence condition is satisfied, as shown in the third time chart of FIG. 4, after the relay control unit 64 turns on the relay 10 in the off state after the time point T12 and then turns it off, the relay control unit 64 performs a deicing operation of hitting the fixed contact 22 with the movable contact 24. The relay control unit 64 intermittently repeats the deicing operation at a predetermined deicing time interval during a predetermined deicing period.

[0055] In the ice crushing operation, the relay control unit 64 turns on relay 10 and then turns off relay 10 without delay. From the perspective of reducing power consumption, it is preferable that the time from when relay 10 is turned on to when it is turned off in the ice crushing operation is sufficiently short with respect to the ice crushing time interval, for example, 1 second or less. However, it is not limited to this example and can be any time.

[0056] When relay 10 is turned on by the ice crushing operation, the fixed contact 22 is struck by the movable contact 24. Then, if ice has formed on the contact surface where the movable contact 24 contacts the fixed contact 22 or on the contact surface where the fixed contact 22 contacts the movable contact 24, the ice can be crushed by the impact of the collision between the contacts 21. By crushing the ice on contacts 21 through the ice crushing operation, the ice formed on the surface of the fixed contact 22 can be removed, and it is possible to suppress the insulation between contacts 21 due to the ice.

[0057] Also, in the ice crushing operation, the ice on the contact surfaces of the fixed contact 22 and the movable contact 24 can be directly crushed. Thereby, the growth of the ice on the contact surface can be suppressed. Regarding the ice on the side surface of the fixed contact 22 or the side surface of the movable contact 24, it is difficult to directly crush it, so the ice on the side surface may grow. However, even if the ice on the side surface grows, since the possibility of insulation between contacts 21 is low, the growth of the ice on the side surface can be tolerated.

[0058] Also, if the state where ice is likely to form continues after the ice crushing operation, ice may form on contacts 21 again. However, since the relay control unit 64 intermittently repeats the ice crushing operation at the ice crushing time interval, even if ice forms on contacts 21 again, the ice can be crushed by the repeated ice crushing operation.

[0059] The ice crushing time interval is the time interval for repeating the ice crushing operation. For example, as shown in the third time chart of FIG. 4, it is the period from relay off to relay on. The ice crushing time interval is set to the time until the ice formed on the contacts of relay 10 grows to a predetermined size. The predetermined size may be set to be equal to or less than the maximum value of the size of the ice that can be crushed by one ice crushing operation. Thereby, the ice formed on the contacts of relay 10 can be more reliably crushed and removed by the ice crushing operation performed at the ice crushing time interval.

[0060] Here, the inventor conducted an experiment on the ice crushing time interval. As a result, if the ice crushing time interval is 4 minutes or less, the probability of being able to crush the ice is high, and if the ice crushing time interval exceeds 4 minutes, the probability of not being able to crush the ice becomes high. That is, 4 minutes in this example corresponds to the time until the ice formed on the contacts of relay 10 grows to the maximum value of the size of the ice that can be crushed by one ice crushing operation. Also, if the ice crushing time interval is short, the power consumption associated with the on / off of relay 10 may increase. Therefore, the ice crushing time interval is preferably 30 seconds or more and 4 minutes or less. If the ice crushing time interval is 30 seconds or more and 4 minutes or less, the ice on the contacts is in a small and soft state, and the ice crushing operation can be performed, making it possible to easily crush the ice on contacts 21. The ice crushing time interval may be set to, for example, 1 minute. Note that the ice crushing time interval is not limited to the exemplified 1 minute and may be set to any time within the range of 30 seconds or more and 4 minutes or less.

[0061] During the ice crushing period, as shown in the third time chart of FIG. 4, the starting point is the time T12 when the relay 10 is turned off in response to the operation stop of the drive source. The ice crushing period is a period set according to the temperature difference ΔT between the temperature Tc of the contact point 21 and the temperature Tin of the internal atmosphere. That is, the ice crushing period is set at least within the period during which the temperature difference ΔT occurs. For example, the ice crushing period is set to the combined period of the first period and the second period. In this case, the ice crushing operation is not performed in the third period. In the third period, since the temperature difference ΔT decreases, the growth of icing is slowed down. Therefore, if the ice crushing operation is performed before the third period to crush the icing, the possibility of further growth of the icing in the third period is reduced. The ice crushing period is longer than the ice crushing time interval, for example, about 20 to 30 minutes, but can be set arbitrarily.

[0062] Note that the ice crushing period is not limited to the combined period of the first period and the second period. The ice crushing period may be set in the first period, or may be set to the combined period of the first period, the second period, and the third period. The ice crushing period preferably includes the first period, that is, the period during which the temperature difference ΔT increases with the passage of time. The relay control unit 64 can appropriately crush the icing by performing the ice crushing operation in the first period when the icing is likely to grow.

[0063] The ice crushing period and the ice crushing time interval may vary depending on the specifications of the relay 10 or the engine 4. For example, the ice crushing period and the ice crushing time interval may be determined in advance for each specification of the relay 10 or the engine 4 by experiments or simulations. The determined ice crushing period and ice crushing time interval may be stored in advance in the memory 62.

[0064] Also, the ice crushing time interval may be set within the range of 30 seconds or more and 4 minutes or less based on the magnitude of the inrush current between the movable contact 24 and the fixed contact 22 when the relay 10 is turned on in the ice crushing operation. The larger the capacitance of the capacitor 72 electrically connected to the movable contact 24 or the fixed contact 22, the larger the magnitude of the inrush current.

[0065] For example, at the timing when relay 10 is turned on by the ice crushing operation, an inrush current with a current value temporarily larger than the steady current flows between the fixed contact 22 and the movable contact 24 to charge the capacitor 72. Therefore, between the fixed contact 22 and the movable contact 24, in addition to the impact between the contacts 21, heat generation due to the inrush current or heat generation due to arcing when the electrical connection is interrupted by the bounce of the movable contact 24 at the moment of impact occurs. The larger the inrush current, the greater the heat generation due to the inrush current. The ice on the contact 21 is crushed by both the impact between the fixed contact 22 and the movable contact 24 and the heat generation due to the inrush current. That is, even if the ice cannot be crushed only by the impact between the fixed contact 22 and the movable contact 24, the heat generation due to the inrush current is added, making it possible to crush the ice. As a result, as the inrush current increases, it becomes possible to increase the ice crushing time interval.

[0066] Also, the ice crushing time interval may be set based on the impact force when the movable contact 24 collides with the fixed contact 22 due to the turning on of the relay 10 in the ice crushing operation within the range of 30 seconds or more and 4 minutes or less. The impact force can be derived based on the physical structure of the relay 10, and can be derived, for example, based on the mass of the movable contact 24 and the moving speed of the movable contact 24. The greater the mass of the movable contact 24 and the moving speed of the movable contact 24, the greater the impact force. The mass of the movable contact 24 and the moving speed of the movable contact 24 vary depending on the specifications of the relay 10. Also, the moving speed of the movable contact 24 changes depending on the magnitude of the current flowing through the excitation coil 28. For example, when the current value of the excitation coil 28 is increased, the attractive force of the excitation coil 28 becomes stronger, and the moving speed of the movable contact 24 increases.

[0067] For example, even if the ice cannot be crushed with a predetermined impact force, by turning on the relay 10 with an impact force greater than the predetermined impact force, it becomes possible to crush the ice. As a result, as the impact force between the fixed contact 22 and the movable contact 24 increases, it becomes possible to increase the ice crushing time interval.

[0068] Note that the ice crushing time interval may be set based on both the magnitude of the above-mentioned inrush current and the magnitude of the above-mentioned impact force within a range of 30 seconds or more and 4 minutes or less.

[0069] Here, the processor 60 that functions as the relay control unit 64 has a run state and a sleep state. The run state is the normal operating state of the processor 60, and the processor 60 in the run state can execute various processes. The sleep state is a state in which the processes that can be executed are limited compared to the run state, and the power consumption is suppressed while waiting. The processor 60 can transition from the run state to the sleep state. In addition, the processor 60 is provided with a self-wake-up function that autonomously wakes up from the sleep state and transitions to the run state.

[0070] As described above, the relay control unit 64 turns off the relay 10 at the time point T12 which is the start time of the ice crushing period. At the time point T12, the relay control unit 64 turns off the relay 10 and, as shown in the fourth time chart of FIG. 4, transitions to the sleep state.

[0071] As shown in the fourth time chart of FIG. 4, when the ice crushing time interval has elapsed, in other words, when the execution timing of the ice crushing operation has arrived, the relay control unit 64 wakes up from the sleep state. The relay control unit 64 that has woken up and become the run state performs an ice crushing operation in which the relay 10 is turned on and then turned off without delay. After the execution of the ice crushing operation, the relay control unit 64 transitions from the run state to the sleep state. The relay control unit 64 repeats waking up and sleeping after the execution of the ice crushing operation every time the execution timing of the ice crushing operation arrives.

[0072] In this way, the relay control unit 64 becomes the run state only when performing the ice crushing operation during the ice crushing period. Therefore, the relay control unit 64 can suppress the power consumption compared to the mode in which the run state continues during the ice crushing period.

[0073] FIG. 5 is a flowchart for explaining the operation flow of the relay control unit 64 according to the present embodiment. The relay control unit 64 repeats a series of processes in FIG. 5 at a predetermined interruption timing that is visited at a predetermined control cycle in the IG-ON state.

[0074] When the predetermined interruption timing occurs, the relay control unit 64 determines whether or not a signal indicating IG-OFF has been acquired from the ignition switch 84 (S10). If a signal indicating IG-OFF has not been acquired (NO in S10), the relay control unit 64 ends the series of processes in FIG. 5.

[0075] If a signal indicating IG-OFF has been acquired (YES in S10), the relay control unit 64 stops the engine 4 which is the drive source (S11). Then, the relay control unit 64 keeps the relay 10 in the ON state for a predetermined self-shutdown time (S12). While the relay 10 is kept in the ON state, the control device 12 performs self-diagnosis of each device.

[0076] When the self-shutdown time has elapsed, the relay control unit 64 acquires the state of the heat source (S13). For example, as an example of the state of the heat source, the relay control unit 64 acquires the temperature of the drive source. More specifically, the relay control unit 64 acquires the detection result of the water temperature sensor 82 as the temperature of the drive source. Next, the relay control unit 64 acquires the outside air temperature from the outside air temperature sensor 80 (S14).

[0077] Next, the relay control unit 64 determines whether or not the ice formation occurrence condition is satisfied based on the acquired state of the heat source and the outside air temperature (S15). The ice formation occurrence condition is a condition under which ice can form on the contacts of the relay 10. For example, the relay control unit 64 determines that the ice formation occurrence condition is satisfied when the outside air temperature is below freezing and the temperature of the drive source, which is an example of the state of the heat source, is equal to or higher than a predetermined temperature set in advance. The predetermined temperature for the temperature of the drive source is set to a temperature that can distinguish that the drive source is sufficiently warmed up.

[0078] When it is determined that the icing generation conditions are not satisfied (NO in S15), the relay control unit 64 turns off the relay 10 (S16). For example, the relay control unit 64 cuts off the current of the excitation coil 28 by turning off the excitation switch 74. Then, the attractive force of the excitation coil 28 disappears, and the movable contact 24 moves in a direction away from the fixed contact 22 by the biasing force of the biasing member 26, and the relay 10 is turned off. After turning off the relay 10, the relay control unit 64 transitions to the sleep state (S17) and ends a series of processes.

[0079] On the other hand, when it is determined that the icing generation conditions are satisfied (YES in S15), the relay control unit 64 sets the ice crushing period (S20). For example, in the memory 62, the ice crushing period is stored in advance for each specification of the drive source and the relay 10. The relay control unit 64 reads out and sets the ice crushing period corresponding to the specifications of the drive source and the relay 10 of the host vehicle from the memory 62.

[0080] Next, the relay control unit 64 sets the ice crushing time interval (S21). For example, in the memory 62, the ice crushing time interval is stored in advance for each specification of the drive source, the relay 10, and the capacitor 72. The relay control unit 64 reads out and sets the ice crushing time interval corresponding to the specifications of the drive source, the relay 10, and the capacitor 72 of the host vehicle from the memory 62. Specifically, the ice crushing time interval is set to a specific time interval within the range of 30 seconds or more and 4 minutes or less.

[0081] Next, the relay control unit 64 turns off the relay (S22). For example, the relay control unit 64 cuts off the current of the excitation coil 28 by turning off the excitation switch 74. Then, the attractive force of the excitation coil 28 disappears, and the movable contact 24 moves in a direction away from the fixed contact 22 by the biasing force of the biasing member 26, and the relay 10 is turned off. After turning off the relay 10, the relay control unit 64 transitions to the sleep state (S23). Then, after the relay control unit 64 performs the ice crushing process (S24), it ends a series of processes. The ice crushing process is a process of intermittently repeating a predetermined ice crushing operation at the set ice crushing time interval during the set ice crushing period.

[0082] FIG. 6 is a flowchart for explaining the flow of the ice crushing process (S24) according to the present embodiment. When the ice crushing process is started, the relay control unit 64 determines whether or not an ice crushing period has elapsed (S30). For example, the relay control unit 64 has a first timer that measures the time taken for the ice crushing period. The relay control unit 64 starts the measurement of the first timer at the timing when the ice crushing process is started. When the measurement of the first timer reaches a predetermined time or more indicating the ice crushing period, the relay control unit 64 determines that the ice crushing period has elapsed.

[0083] If it is determined that the ice crushing period has not elapsed (NO in S30), the relay control unit 64 determines whether or not the ice crushing timing, which is the timing for executing the ice crushing operation, has arrived (S31). For example, the relay control unit 64 has a second timer that measures the time taken for the ice crushing time interval. The relay control unit 64 starts the measurement of the second timer at the timing when the ice crushing process is started. When the measurement of the second timer reaches a predetermined time or more indicating the ice crushing time interval, the relay control unit 64 determines that the ice crushing timing has arrived.

[0084] If it is determined that the ice crushing timing has not arrived (NO in S31), the relay control unit 64 returns to the process of step S30 and repeats the processes after step S30.

[0085] Note that the determination regarding the ice crushing period in step S30 and the determination regarding the arrival of the ice crushing timing in step S31 are executed by the processor 60 functioning as the relay control unit 64 in the sleep state. In the sleep state, the functions to be executed are limited, but necessary processes such as step S30 and step S31 can be executed.

[0086] If it is determined that the ice crushing timing has arrived (YES in S31), the relay control unit 64 wakes up from the sleep state and transitions to the run state (S32). Thereby, the limitation of the functions in the processor 60 is released.

[0087] After waking up, the relay control unit 64 turns on the relay 10 (S33). For example, the relay control unit 64 passes a current through the exciting coil 28 by turning on the exciting switch 74. Then, an attractive force is generated in the exciting coil 28, and due to this attractive force, the movable contact 24 moves in a direction approaching the fixed contact 22, and the relay 10 is turned on. At this time, the movable contact 24 strikes the fixed contact 22. Even if icing has occurred on the contact 21, the impact of the movable contact 24 striking the fixed contact 22 can break the icing.

[0088] After turning on the relay 10 in step S33, the relay control unit 64 turns off the relay 10 without delay (S34). For example, the relay control unit 64 cuts off the current of the exciting coil 28 by turning off the exciting switch 74. Then, the attractive force of the exciting coil 28 disappears, and due to the biasing force of the biasing member 26, the movable contact 24 moves in a direction away from the fixed contact 22, and the relay 10 is turned off. The time from the turning on of the relay 10 in step S33 to the turning off of the relay 10 in step S34 is sufficiently short compared to the ice crushing time interval.

[0089] After turning off the relay 10 in step S34, the relay control unit 64 transitions from the running state to the sleep state (S35). Then, the relay control unit 64 returns to the process of step S30 and repeats the processes after step S30.

[0090] Although omitted in FIG. 6, when turning off the relay 10 in step S34, the relay control unit 64 resets the timing of the second timer and starts timing. Then, when the process according to the ice crushing timing of step S31 is performed again via the processes from step S32 to step S35, the time from the most recent relay off is measured. Thereby, the relay control unit 64 can appropriately manage the ice crushing time interval.

[0091] The relay control unit 64 repeats the processes from step S30 to step S35 until the ice crushing period elapses. When the ice crushing period has elapsed (YES in S30), the relay control unit 64 ends the ice crushing process.

[0092] As described above, the control device 12 of the relay 10 according to the present embodiment determines whether or not the ice formation generation condition is satisfied after the operation of the drive source stops, based on at least one of the state of the heat source and the outside air temperature. When it is determined that the ice formation generation condition is satisfied, the control device 12 intermittently repeats the ice crushing operation of hitting the fixed contact 22 with the movable contact 24 by turning on and then turning off the relay 10 in the off state at a predetermined ice crushing time interval during a predetermined ice crushing period. The ice crushing period is a period set according to the temperature difference ΔT between the temperature Tc of the contact 21 of the relay 10 and the temperature Tin of the internal atmosphere of the relay 10. The ice crushing time interval is the time until the ice formation growing on the contact of the relay 10 grows to a predetermined size. Therefore, the control device 12 according to the present embodiment can crush and remove the ice formation by the ice crushing operation even if ice formation occurs on the contact 21 of the relay 10.

[0093] Therefore, according to the control device 12 of the present embodiment, it is possible to appropriately deal with the ice formation generated on the contact 21 of the relay 10.

[0094] In the present embodiment, the predetermined size may be set to be equal to or less than the maximum value of the size of the ice formation that can be crushed by one ice crushing operation. Thereby, the control device 12 according to the present embodiment can surely crush and remove the ice formation by the ice crushing operation.

[0095] In the present embodiment, it is more preferable that the ice crushing time interval is 4 minutes or less, which corresponds to the time until the ice formation growing on the contact of the relay 10 grows to the maximum value of the size of the ice formation that can be crushed by one ice crushing operation. Also, in order to suppress the power consumption associated with the on / off operation of the relay 10, it is more preferable that the ice crushing time interval is 30 seconds or more. That is, it is more preferable that the ice crushing time interval is 30 seconds or more and 4 minutes or less.

[0096] Also, in the present embodiment, the predetermined ice crushing period may include a period in which the temperature difference ΔT between the temperature Tc of the contact point 21 and the temperature Tin of the internal atmosphere increases with time. Therefore, in the control device 12 of the present embodiment, the ice crushing operation is performed during a period when icing is likely to occur, and the ice can be appropriately crushed.

[0097] Also, in the present embodiment, the predetermined ice crushing time interval may be set based on the magnitude of the inrush current between the movable contact 24 and the fixed contact 22 when the relay 10 in the ice crushing operation is turned on. Thereby, in the control device 12 of the present embodiment, the ice crushing time interval can be set to an appropriate time interval, such as increasing the ice crushing time interval according to the magnitude of the inrush current.

[0098] Also, in the present embodiment, the predetermined ice crushing time interval may be set based on the impact force when the movable contact 24 collides with the fixed contact 22 when the relay 10 is turned on in the ice crushing operation. Thereby, in the control device 12 of the present embodiment, the ice crushing time interval can be set to an appropriate interval, such as increasing the ice crushing time interval according to the magnitude of the impact force.

[0099] Also, the relay control unit 64 of the present embodiment turns off the relay 10 at the start of the ice crushing period and transitions to the sleep state. When the execution timing of the ice crushing operation arrives at every predetermined ice crushing time interval, the relay control unit 64 wakes up from the sleep state and performs the ice crushing operation. The relay control unit 64 transitions to the sleep state after the execution of the ice crushing operation. Thereby, in the control device 12 of the present embodiment, compared with a mode in which the running state is continued during the ice crushing period, the power consumption can be suppressed. That is, in the control device 12 of the present embodiment, it is possible to cope with icing generated at the contact point 21 of the relay 10 while suppressing the power consumption.

[0100] The embodiments of the present invention have been described above with reference to the accompanying drawings. Needless to say, the present invention is not limited to such embodiments. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that those also belong to the technical scope of the present invention.

Description of Reference Numerals

[0101] 1 Vehicle 4 Engine 10 Relay 12 Control Device 22 Fixed Contact 24 Movable Contact 60 Processor 62 Memory

Claims

1. A control device for controlling a relay mounted on a vehicle and having a fixed contact and a movable contact, comprising: one or more processors; one or more memories connected to the processor; and having the processor determining whether or not an icing occurrence condition, which is a condition under which icing can occur at the contacts of the relay, is satisfied after the operation of the drive source of the vehicle has stopped, based on at least one of the state of the heat source of the vehicle and the outside air temperature; when the icing occurrence condition is satisfied, intermittently repeating, at a predetermined time interval, an ice crushing operation of hitting the fixed contact with the movable contact by turning on and then turning off the relay in the off state during a predetermined ice crushing period after the relay is turned off in response to the stop of the operation of the drive source; executing a process including the predetermined ice crushing period is set according to a temperature difference between the temperature of the contacts of the relay and the temperature of the internal atmosphere of the relay; the predetermined time interval is the time until the ice formed on the contacts of the relay grows to a predetermined size, the control device.

2. The control device according to claim 1, wherein the predetermined size is set to be equal to or less than the maximum value of the size of the ice that can be crushed by one ice crushing operation.

3. The control device according to claim 1 or 2, wherein the predetermined ice crushing period includes a period in which the temperature difference increases with time.

4. The control device according to any one of claims 1 to 3, wherein the predetermined time interval is set based on the magnitude of the inrush current between the movable contact and the fixed contact when the relay is turned on in the ice crushing operation.

5. The control device according to any one of claims 1 to 4, wherein the predetermined time interval is set based on the impact force when the movable contact collides with the fixed contact due to the turning on of the relay in the ice crushing operation.

6. the processor turning off the relay and transitioning to a sleep state at the start of the ice crushing period; waking up from the sleep state and performing the ice crushing operation when the execution timing of the ice crushing operation arrives every predetermined time interval; transitioning to the sleep state after the execution of the ice crushing operation; executing a process including, the control device according to any one of claims 1 to 5.

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