Relay control device

Abstract

To provide a relay control device that inhibits freezing of electric contacts of a relay and also enables the freezing problem to be resolved in a short time even if the electric contacts have actually frozen.SOLUTION: When a temperature drops and it becomes necessary to take measures against freezing of contacts, a voltage applied to an electric coil 10b of a relay 10 is automatically switched to a higher voltage than usual. Since a heating value of the electric coil 10b is increased, an area near electric contacts 10a is heated and water freezing is less likely to occur. If freezing has already occurred, the heating will melt the ice in a short time to eliminate icing and malfunction of the electric contacts 10a. A DC / DC converter 21 is controlled to normally output a voltage of 12 V and to temporarily switch to a voltage of 24 V at low temperatures. Alternatively, a semiconductor switch is used to selectively apply a voltage from multiple power supply lines to the electric coil 10b. The voltage is automatically restored to the original voltage when a predetermined amount of time has elapsed or the icing has been eliminated.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a relay control device, and particularly to countermeasures against freezing of electrical contacts in vehicles and the like in a low-temperature environment.

Background Art

[0002] In devices that are susceptible to the influence of environmental temperature and humidity, such as electrical components mounted on automobiles, in a low-temperature environment such as below freezing point, moisture adhering to the vicinity of the contacts freezes, fixing the contacts, and malfunction of the electrical contacts may occur where the opening and closing operation becomes impossible. For example, if the contacts of a relay connected to the power supply in an automobile freeze, it is conceivable that the engine cannot be started.

[0003] For example, Patent Document 1 discloses a device for releasing the freezing of an electromagnetic relay. That is, the control unit determines whether freezing has occurred inside the housing of the electromagnetic relay. When it is determined that freezing has occurred, voltage application and stop to the excitation coil of the electromagnetic relay are repeated, and the movable terminal is repeatedly moved in the direction of approaching and separating from the fixed terminal, thereby generating vibration at the location of freezing inside the housing or the housing, and releasing the freezing.

[0004] Further, Patent Document 2 discloses an electromagnetic switch that has a large force for crushing the ice frozen on the surface of the fixed contact and can easily remove the crushed ice from the contact. Furthermore, Patent Document 3 discloses a relay control device that prevents relay freezing while suppressing the execution of unnecessary anti-freeze control to reduce power consumption. In this relay control device, if the vehicle system is requested to start and the relay contacts are closed when there is no history of the relay contacts being closed for a predetermined period of time within the immediate vicinity, and the vehicle system is requested to stop when the outside temperature is below a predetermined temperature, the relay contacts are opened after an anti-freeze control process that keeps the relay contacts closed for a predetermined period of time after they are closed. On the other hand, if the vehicle system is requested to start and the relay contacts are closed when there is a history of the above within the immediate vicinity, the relay contacts are opened without going through anti-freeze control even if the vehicle system is requested to stop when the outside temperature is below a predetermined temperature. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2007-165406 [Patent Document 2] Japanese Patent Publication No. 2016-39013 [Patent Document 3] Japanese Patent Publication No. 2021-75136 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, regardless of which of the technologies described in Patent Documents 1, 2, and 3 is used, it is difficult to resolve the fundamental problems caused by the freezing of electrical contacts. In other words, in situations where electrical contacts have completely frozen, even if vibrations are generated as in Patent Document 1, or force is applied to crush the ice as in Patent Document 2, it is unlikely that the contacts will be restored to a state where they can open and close. Furthermore, if the contacts have actually frozen, the technology shown in Patent Document 3 cannot resolve the freezing problem.

[0007] Therefore, for example, in cold regions during winter, if the vehicle's engine cannot be started due to the freezing of electrical contacts, the vehicle user will have to spend time trying various methods to warm up the engine compartment and wait for the freezing to thaw.

[0008] This invention has been made in view of the above circumstances, and its purpose is to provide a relay control device that can suppress the freezing of electrical contacts and, even if the electrical contacts do freeze, can resolve the freezing problem in a short time. [Means for solving the problem]

[0009] The above-mentioned objective according to the present invention is achieved by the following configuration.

[0010] A relay having an electric coil and an electric contact whose open / closed state changes according to the current flowing through the electric coil, A power supply circuit having a first power supply line that supplies a first voltage and a second power supply line that supplies a second voltage higher than the first voltage, A voltage selection circuit including a semiconductor switch device, which can selectively connect either the first power line or the second power line to the terminal of the electrical coil of the relay, A temperature detection unit capable of detecting changes in ambient temperature, The system comprises a control unit that controls the voltage selection circuit, The temperature detection unit is capable of detecting the temperature of the vehicle's coolant. When the vehicle is started, the control unit detects that the water temperature or ambient temperature is lower than 0°C, and temporarily switches the output voltage of the voltage selection circuit from the first voltage to the second voltage. Relay control device. [Effects of the Invention]

[0011] The relay control device of the present invention makes it possible to suppress the freezing of electrical contacts, and even if the electrical contacts do freeze, the freezing problem can be resolved in a short time. In other words, in situations where freezing is likely to occur or when freezing has actually occurred, increasing the voltage applied to the electrical coil that drives the relay increases the amount of heat generated by the electrical coil, thus providing the effect of suppressing freezing or resolving freezing in a short time.

[0012] The above is a brief description of the present invention. Further, the details of the present invention will be further clarified by reading through the embodiments for carrying out the invention described below (hereinafter referred to as "embodiments") with reference to the accompanying drawings.

Brief Description of the Drawings

[0013] [Figure 1] FIG. 1 is an electrical circuit diagram showing the configuration of a relay control device according to a reference example of the present invention. [Figure 2] FIG. 2 is a flowchart showing an operation example - 1 of an ECU at vehicle startup. [Figure 3] FIG. 3 is a flowchart showing an operation example - 2 of an ECU at vehicle startup. [Figure 4] FIG. 4 is a flowchart showing an operation example - 3 of an ECU at vehicle startup. [Figure 5] FIG. 5 is an electrical circuit diagram showing the configuration of a relay control device according to an embodiment of the present invention.

Embodiments for Carrying out the Invention

[0014] Specific embodiments and reference examples related to the present invention will be described below with reference to each drawing. FIG. 1 is an electrical circuit diagram showing the configuration of a relay control device 100 according to a reference example of the present invention.

[0015] The relay control device 100 according to the reference example of the present invention is mounted on a vehicle and can be used to control the on / off of power supply to a predetermined load (electrical component) 15 on the vehicle. As an example, the relay control device 100 is used for applications where loads such as a pump that supplies fuel to an engine and headlights are used as the load 15. However, since a relay 10 having an electrical contact 10a that physically opens and closes is used, it is preferably used for applications that do not require strict timing control.

[0016] As shown in FIG. 1, the output of a power supply circuit 11 that outputs a DC power supply voltage of 12 [V] is connected to a 12V power supply line 13 via a fuse 12. The 12V power supply line 13 is connected to one end of a load 15 via an electrical contact 10a within a relay 10 and a 12V power supply line 14, and the other end of the load 15 is connected to a ground 16.

[0017] The relay 10 can physically open and close the electrical contact 10a by turning on and off the energization of an internal electrical coil 10b. However, when the air temperature or water temperature becomes less than 0°C, such as in an outdoor environment in a cold region, freezing of moisture may occur near the electrical contact 10a, and even if the on and off of the energization of the electrical coil 10b is switched, the opening and closing of the electrical contact 10a may not be switched due to malfunction. The relay control device 100 of this reference example is equipped with functions for preventing freezing of the electrical contact 10a and eliminating malfunction caused by freezing.

[0018] The relay control device 100 includes a DC / DC converter 21. This DC / DC converter 21 has a function of boosting voltage and a function of switching multiple types of voltages. The input of the DC / DC converter 21 is connected to the 12V power supply line 13, and the output is connected to a terminal 10c on one end side of the electrical coil 10b via a wire 22. The terminal 10d on the other end side of the electrical coil 10b is connected to a control output 24a of an ECU (Electronic Control Unit) 24 via a wire 23.

[0019] The control output 24b of the ECU 24 is connected to the control input of the DC / DC converter 21 via a control line 26. The DC / DC converter 21 can selectively switch the voltage output to the wire 22 to either 12 [V] or 24 [V] according to the on and off of a control signal SG1 input from the ECU 24. Normally, a voltage of 12 [V] appears on the wire 22. And when it becomes necessary to prevent freezing or eliminate freezing near the electrical contact 10a, the DC / DC converter 21 outputs a voltage of 24 [V] to the wire 22.

[0020] The ECU24 has a function to switch the relay 10 on and off in order to switch the power supply to the load 15 on and off. When the ECU24 switches the control output 24a to a low potential equivalent to that of ground 16, a current ic flows from the wire 22 through the electric coil 10b toward the wire 23. Then, the magnetic energy generated in the electric coil 10b by the current ic moves the movable part of the electric contact 10a, and the open / closed state of the switch is switched. On the other hand, when the ECU24 switches the control output 24a to the open state, no current ic flows, so no magnetic energy is generated from the electric coil 10b, and the movable part of the electric contact 10a moves, and the open / closed state of the switch is switched.

[0021] When electrical contact 10a closes, a load current iL flows to the load 15 through the power supply circuit 11, fuse 12, 12V power line 13, electrical contact 10a, and 12V power line 14, supplying power to the load 15. When electrical contact 10a is open, no load current iL flows, so the operation of the load 15 stops. In other words, the ECU 24 can control the operation of the load 15 using the relay 10.

[0022] Meanwhile, a water temperature gauge 25, which detects the temperature of the coolant in the vehicle, is connected to the input of the ECU 24. Therefore, the ECU 24 can understand changes in ambient temperature and temperature changes on the vehicle based on the information output by the water temperature gauge 25.

[0023] In this example, the ECU24 performs necessary control to prevent freezing near the electrical contact 10a or to resolve the frozen state, based on the temperature information output by the water temperature gauge 25. Specifically, the ECU24 controls the DC / DC converter 21 with the control signal SG1 to switch the voltage appearing in the wire 22.

[0024] When the voltage applied to the wire 22 is increased to a higher level than usual, the current ic flowing through the electrical coil 10b increases in proportion to that voltage. As the current ic increases, the amount of heat generated by the electrical coil 10b also increases. Since the electrical contact 10a, which operates due to the magnetic energy of the electrical coil 10b, is generally located near the electrical coil 10b, an increase in the amount of heat generated by the electrical coil 10b makes it less likely for moisture to freeze near the electrical contact 10a, even at low temperatures. In addition, any ice that does form near the electrical contact 10a is heated and melts more easily. In other words, malfunctions of the electrical contact 10a caused by moisture freezing at low temperatures can be automatically resolved.

[0025] As a specific example, let's consider the case where the resistance Rc of the electric coil 10b is 300 [Ω]. (1) When the potential difference Vc between the terminals of the electric coil 10b is 12[V]: ic = Vc / Rc = 12 / 300 =0.04[A] Wc=Vc 2 / Rc =0.48[W] Wc: Power consumption of electric coil 10b

[0026] (2) When the potential difference Vc between the terminals of the electric coil 10b is 24[V]: ic = Vc / Rc =24 / 300 =0.08[A] Wc=Vc 2 / Rc =1.92[W]

[0027] Since the amount of heat generated by the electric coil 10b is proportional to its power consumption Wc, increasing the power consumption Wc by switching the voltage applied to the wire 22 from 12[V] to 24[V] can increase the amount of heat generated, which helps to resolve freezing.

[0028] <Example of operation-1> Figure 2 shows an example of ECU24 operation-1 during vehicle startup. For example, in cold regions, when a vehicle is started after being parked outdoors for a long period of time, the movable part of the electrical contact 10a will be cooled by the outside air while stationary, and no heat will be generated on the vehicle. As a result, moisture may freeze near the electrical contact 10a, potentially causing the electrical contact 10a to become immobile. Therefore, when starting the vehicle, it is preferable to perform the operation shown in Figure 2 as a measure against freezing of the electrical contact 10a. For example, the operation shown in Figure 2 is started at the moment the vehicle's ignition is turned on.

[0029] In its initial state, the ECU24 controls the control signal SG1 to cause the DC / DC converter 21 to apply a voltage of 12[V] to the electric coil 10b via the wire 22 (S11).

[0030] The ECU24 monitors the signal output by the water temperature gauge 25 to detect the current water temperature Tc (S12). Alternatively, ambient temperature may be detected instead of water temperature. The ECU24 compares the water temperature Tc detected in S12 with 0°C (S13), and if it is below 0°C, meaning there is a possibility of water freezing, it proceeds to the process in S14.

[0031] If the water temperature Tc is below 0°C, the ECU24 controls the control signal SG1 to switch the DC / DC converter 21 to a state where it applies a voltage of 24[V] to the electric coil 10b via the wire 22 (S14). After this, ECU24 will wait in S15 until it detects that a certain amount of time has elapsed.

[0032] After a certain period of time has elapsed, the ECU 24 controls the control signal SG1 to return the DC / DC converter 21 to the state in which it applies a voltage of 12[V] to the electric coil 10b via the wire 22, just as it did in the initial state (S16). In other words, the freeze prevention operation for the electric contact 10a is terminated.

[0033] When the anti-freezing operation is not required, returning the voltage applied to the electric coil 10b to the normal voltage reduces unnecessary heat generation and power consumption in the electric coil 10b, thereby extending the lifespan of the relay 10.

[0034] <Example of operation - 2> Figure 3 shows an example of ECU24 operation during vehicle startup (Example 2). In the operation shown in Figure 3, the ECU 24 processes the length of time it waits in S15A to be automatically adjusted according to the water temperature or ambient temperature detected by the water temperature gauge 25.

[0035] For example, if the water temperature Tc is close to 0°C, it is highly likely that the freezing of the electrical contact 10a can be thawed by a short heating period due to the heat generated by the electrical coil 10b, so the waiting time is shortened. On the other hand, if the water temperature Tc is very low, such as -10°C, it is expected that it will take time to thaw the freezing of the electrical contact 10a, so the waiting time is lengthened.

[0036] <Example of operation - 3> Figure 4 shows an example of ECU24 operation-3 during vehicle startup. In the operation shown in Figure 4, the length of time that ECU24 waits in S15B is not fixed. After ECU24 actually detects that the freezing has been resolved, it proceeds from S15B to S16 and returns the voltage applied to the electric coil 10b to 12[V].

[0037] For example, the ECU 24 can detect that the freezing of the electrical contact 10a has been undone by detecting that the electrical contact 10a has switched from an open state to a closed state and a voltage of 12[V] has appeared on the 12V power line 14. Alternatively, the load current iL may be detected instead of the voltage on the 12V power line 14, or a signal generated by the operation of the load 15 may be monitored. The vehicle's engine may also be detected as having started. Furthermore, the undone of the freezing may be detected by the rise in water temperature detected by the water temperature gauge 25.

[0038] <Configuration of the embodiment> Figure 5 is an electrical circuit diagram showing the configuration of a relay control device 100A according to an embodiment of the present invention. Components similar to those in the reference example described above are denoted by the same reference numerals and their descriptions are omitted. The relay control device 100A shown in Figure 5 includes a power supply circuit 11 that outputs a DC power supply voltage of 12[V], as well as a power supply circuit 11A that outputs a DC power supply voltage of 24[V].

[0039] The output of one power supply circuit 11 is connected to a 12V power line 13 via a fuse 12. The output of the other power supply circuit 11A is connected to a 24V power line 33 via a fuse 12A.

[0040] The 12V power line 13 is connected to one end of the load 15 via the electrical contact 10a in the relay 10 and the 12V power line 14, and the other end of the load 15 is connected to ground 16. The configuration of the relay 10 shown in Figure 5 is the same as that of the relay control device 100 in Figure 1.

[0041] The relay control device 100A shown in Figure 5 includes two semiconductor switch devices 31 and 32 to selectively switch the voltage supplied to the electric coil 10b of the relay 10. Each semiconductor switch device 31 and 32 can be switched between conducting and non-conducting by a binary signal applied to the control input.

[0042] One semiconductor switch device 31 is connected between the 12V power line 13 and the wire 34. The other semiconductor switch device 32 is connected between the 24V power line 33 and the wire 34.

[0043] The control output 24b of ECU24A is connected to the control input of semiconductor switch device 31 via control line 26A. Additionally, the control output 24c of ECU24A is connected to the control input of semiconductor switch device 32 via control line 26B.

[0044] The ECU24A can switch the on / off (conductive / non-conductive) state of semiconductor switch devices 31 and 32 by controlling the control signals SG2 and SG3 output to control outputs 24b and 24c.

[0045] In this embodiment, the ECU 24A selects either a first state in which the semiconductor switch device 31 is conductive and the semiconductor switch device 32 is non-conductive, or a second state in which the semiconductor switch device 32 is conductive and the semiconductor switch device 31 is non-conductive. If the ECU 24A selects the first state, the voltage (12[V]) of the 12V power line 13 is supplied to the wire 34 via the semiconductor switch device 31. If the second state is selected, the voltage (24[V]) of the 24V power line 33 is supplied to the wire 34 via the semiconductor switch device 32.

[0046] In other words, the ECU24A controls two semiconductor switch devices 31 and 32, allowing the voltage applied to the electrical coil 10b of the relay 10 to be selectively switched between 12[V] and 24[V]. Therefore, the relay control device 100A shown in Figure 5 can perform operations to prevent or resolve freezing of the electrical contact 10a, similar to the relay control device 100 shown in Figure 1. Examples of operation include operation examples 1 to 3 shown in Figures 2 to 4, similar to the case of the ECU24 described as a reference example.

[0047] In addition, the voltage and current applied from the wire 23 to each ECU 24 and 24A in each relay control device 100 and 100A will fluctuate, but this is within the allowable range of the voltage withstand voltage and current values ​​in the internal circuitry of each ECU and therefore does not pose a problem.

[0048] As described above, the relay control devices 100 and 100A can temporarily increase the heat generated by the electric coil 10b when the ambient temperature drops below freezing, thereby preventing the freezing of moisture near the electric contact 10a. Furthermore, even if freezing does occur near the electric contact 10a, the heat generated by the electric coil 10b can warm the frozen area and melt the ice in a short time. Therefore, malfunctions of the electric contact 10a of the relay 10 can be resolved, especially in cold regions when starting a vehicle. Furthermore, since there is no need to use a special relay with a configuration that prevents electrical contact freezing, component costs can be reduced.

[0049] Furthermore, the present invention is not limited to the embodiments and reference examples described above, and can be modified, improved, etc., as appropriate. In addition, the material, shape, dimensions, number, placement, etc. of each component in the embodiments and reference examples described above are arbitrary and not limited, as long as they can achieve the present invention.

[0050] For example, in the configurations shown in Figures 1 and 5, the ECU 24 determines the temperature based on the water temperature detected by the water temperature gauge 25, but a temperature sensor that detects the ambient temperature could also be used. However, since the water temperature gauge 25 is commonly installed in existing vehicles, using the water temperature gauge 25 eliminates the need to install additional sensors to detect water temperature and ambient temperature, thus reducing costs.

[0051] Furthermore, while the configurations shown in Figures 1 and 5 only illustrate the case where the ECU24 automatically starts and stops the voltage switching control for anti-freezing measures, the ECU24 may also start the voltage switching control for anti-freezing measures in response to, for example, a user button press. Similarly, the termination conditions for the control may also be determined in response to a user button press.

[0052] Herein, the features of the relay control device according to the embodiment of the present invention described above are briefly summarized and listed below in [1] to [3]. [1] A relay (10) having an electric coil and an electric contact whose open / closed state changes according to the current flowing through the electric coil, A power supply circuit (power supply circuit 11, 11A) having a first power supply line (12V power supply line 13) that supplies a first voltage and a second power supply line (24V power supply line 33) that supplies a second voltage higher than the first voltage, A voltage selection circuit including semiconductor switch devices (31, 32) that can selectively connect either the first power line or the second power line to the terminal of the electric coil of the relay, A temperature detection unit (water thermometer 25) capable of detecting changes in ambient temperature, A control unit (ECU24A) that controls the voltage selection circuit, Equipped with, Based on the detection state of the temperature detection unit, the control unit temporarily switches the output voltage of the voltage selection circuit from the first voltage to the second voltage when it detects a predetermined low temperature (S12~S14). Relay control device.

[0053] According to the relay control device with the configuration described in [1] above, the voltage applied to the electrical coil can be temporarily increased when there is a possibility of freezing of moisture near the electrical contacts, or when freezing has already occurred. Therefore, the amount of heat generated by the electrical coil increases, which has the effect of preventing the freezing of moisture. In addition, if freezing has already occurred, the freezing can be resolved in a short time.

[0054] [2] The control unit switches the output voltage of the voltage selection circuit from the first voltage to the second voltage, and then after a predetermined time has elapsed or a predetermined condition has been met, it automatically switches the output voltage of the voltage selection circuit from the second voltage to the first voltage. The relay control device described in [1] above.

[0055] According to the relay control device with the configuration described in [2] above, when measures to prevent freezing of the electrical contacts are no longer necessary, the voltage applied to the electrical coil can be automatically returned to its original state. This suppresses unnecessary heat generation and power consumption from the electrical coil.

[0056] [3] When the temperature detection unit detects that the water temperature or ambient temperature is lower than 0°C during vehicle startup, the control unit temporarily switches the output voltage of the voltage selection circuit from the first voltage to the second voltage. The relay control device described in [1] above.

[0057] According to the relay control device with the configuration described in [3] above, malfunctions of the relay's electrical contacts caused by the freezing of moisture when starting the vehicle's engine can be automatically resolved. This eliminates the need for the vehicle user to perform troublesome tasks to resolve the malfunction, and also shortens the time required to resolve the malfunction. [Explanation of symbols]

[0058] 10 Relay 10a electrical contact 10b Electric coil 10c, 10d terminals 11,11A power supply circuit 12,12A fuse 13,14 12V power line 15 load 16 Grand 21 DC / DC Converters 22,23,34 Electric wire 24,24A ECU 25 Water temperature gauge 26, 26A, 26B control lines 31,32 Semiconductor Switch Devices 33 24V power line 100, 100A Relay Control Device iL Load current ic current SG1, SG2, SG3 control signals

Claims

1. A relay having an electric coil and an electric contact whose open / closed state changes according to the current flowing through the electric coil, A power supply circuit having a first power supply line that supplies a first voltage and a second power supply line that supplies a second voltage higher than the first voltage, A voltage selection circuit including a semiconductor switch device, which can selectively connect either the first power line or the second power line to the terminal of the electrical coil of the relay, A temperature detection unit capable of detecting changes in ambient temperature, A control unit that controls the voltage selection circuit, Equipped with, The temperature detection unit is capable of detecting the temperature of the vehicle's coolant. When the vehicle is started, the control unit detects that the water temperature or ambient temperature is lower than 0°C, and temporarily switches the output voltage of the voltage selection circuit from the first voltage to the second voltage. Relay control device.

2. The control unit, after switching the output voltage of the voltage selection circuit from the first voltage to the second voltage, automatically switches the output voltage of the voltage selection circuit from the second voltage to the first voltage when a predetermined time has elapsed or when predetermined conditions are met. The relay control device according to claim 1.

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