Vehicle relay dehumidifier

Abstract

To suitably suppress freezing of contacts of a mechanical relay.SOLUTION: A relay dehumidifier 1 includes a relay housing 22 that accommodates a mechanical relay body 21 and is individually communicated with a surge tank 30 and an evaporator 40, a solenoid valve 32 disposed in a first communication pipe 31 that communicates the surge tank 30 and the relay housing 22; an ECU 50, and the ECU 50 closes the solenoid valve 32 under a normal condition, and opens the solenoid valve 32 when the surge tank 30 generates negative pressure and the humidity at the outlet 40b of the evaporator 40 is below a predetermined value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a technique for dehumidifying the interior of a mechanical relay mounted on a vehicle.

Background Art

[0002] In a mechanical relay mounted on a vehicle, the humidity inside the relay housing increases as moisture contained in the coil gradually evaporates. When the humidity inside the relay housing increases, the contacts may dew and freeze in a low-temperature environment. If the contacts freeze, the contact is inhibited and a conduction failure may occur.

[0003] Therefore, in the technique described in Patent Document 1, by increasing the excitation current of the coil, the moisture contained in the coil is evaporated to increase the internal pressure of the relay housing, and the humid air inside the relay housing is discharged to the outside through the through holes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the technique described in Patent Document 1 does not function effectively when the moisture contained in the coil decreases. In addition, since the relay housing is provided with through holes, there is a risk that moist air may flow in from the through holes.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to suitably suppress the freezing of the contacts of a mechanical relay.

Means for Solving the Problems

[0007] To achieve the above object, an embodiment of the present invention is A relay dehumidifier for a vehicle, A relay housing that houses the mechanical relay body and is individually connected to the negative pressure source and the evaporator, A valve is positioned in a connecting pipe that connects the negative pressure source and the relay housing, It comprises a valve control unit, The valve control unit, The valve is normally closed. The valve is opened when the negative pressure source generates negative pressure and the humidity at the outlet of the evaporator is below a predetermined value. It is characterized by the following: [Effects of the Invention]

[0008] According to the present invention, freezing of the contacts of a mechanical relay can be effectively suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing the schematic configuration of a vehicle equipped with a relay dehumidifier according to an embodiment. [Figure 2] This is a flowchart showing the operation flow of the relay dehumidifier according to the embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings.

[0011] Figure 1 is a block diagram showing the schematic configuration of a vehicle 100 equipped with a relay dehumidifier 1 according to this embodiment. The relay dehumidifier 1 according to this embodiment is mounted on a vehicle 100 and dehumidifies the inside of a mechanical relay 20.

[0012] The mechanical relay 20 comprises a mechanical relay body 21 and a relay housing 22 that houses the mechanical relay body 21. In the mechanical relay body 21, the coil 211 is energized, causing the magnetized iron core 212 to attract the axle 213, which in turn causes the two contacts 214 to make contact. As a result, electrical equipment (not shown) connected to the two contacts 214 operates.

[0013] The relay housing 22 is made of, for example, epoxy resin or PBT resin, and seals the internal mechanical relay body 21 to a predetermined degree of airtightness. The relay housing 22 is individually connected to the surge tank 30 and the evaporator 40. Specifically, the relay housing 22 and the surge tank 30 are connected via a first connecting pipe 31, and the relay housing 22 and the outlet 40b of the evaporator 40 are connected via a second connecting pipe 41. The surge tank 30 is a container-like part located in the intake manifold of the engine 35, which is an internal combustion engine, and temporarily stores the intake air flowing towards the cylinders. The evaporator 40 is a device that cools and / or dehumidifies the air inside the passenger compartment of the vehicle 100. More specifically, in the evaporator 40, the air inside the passenger compartment, blown by the fan 40a, is cooled by heat exchange with the refrigerant, and the condensed water produced at that time is discharged to the outside. Therefore, when the evaporator 40 is operating, dehumidified dry air is discharged from the outlet 40b of the evaporator 40.

[0014] A solenoid valve 32 is located in the first connecting pipe 31. The solenoid valve 32 is an example of a valve according to the present invention, and in this embodiment, it is positioned in the communication portion between the first communication pipe 31 and the relay housing 22 to open and close the communication portion. The opening and closing operation of the solenoid valve 32 is controlled by the ECU (Electronic Control Unit) 50 which electronically controls the engine 35. The solenoid valve 32 is in a closed state when it is not opened by the ECU 50. The relay dehumidifier 1 includes at least the relay housing 22, the solenoid valve 32, and the ECU 50.

[0015] A check valve 42 and a humidity sensor 43 are located in the second connecting pipe 41. The check valve 42 keeps the flow in the second communication pipe 41 in only one direction from the outlet of the evaporator 40 into the relay housing 22 and suppresses its reverse flow. In this embodiment, the check valve 42 is arranged at the communication part between the first communication pipe 31 and the relay housing 22 and is configured to keep the pressure difference between the inside of the relay housing 22 and the outside constant under normal conditions. That is, the pressure inside the relay housing 22 under normal conditions is kept substantially constant through the check valve 42. However, the position of the check valve 42 is not particularly limited as long as it is somewhere in the part that communicates the outlet of the evaporator 40 and the inside of the relay housing 22. The humidity sensor 43 measures the humidity at the outlet 40b of the evaporator 40 and outputs the measured humidity value to the ECU 50. Note that the position of the humidity sensor 43 is not particularly limited as long as it can measure the humidity at the outlet 40b of the evaporator 40, and it may be arranged in the second communication pipe 41 or in the evaporator 40.

[0016] Subsequently, the operation of the relay dehumidifying device 1 will be described. <(span style="font-size:10pt;"> Figure 2 is a flowchart showing the flow of the operation of the relay dehumidifying device 1. As described above, under normal conditions, the solenoid valve 32 is closed and it is assumed that the inside of the first communication pipe 31 is blocked.

[0017] As shown in Figure 2, first, the ECU 50 determines whether the engine 35 is operating (step S1). If it is determined that the engine 35 is not operating (step S1; No), the process proceeds to step S5 described later.

[0018] On the other hand, if it is determined in step S1 that the engine 35 is operating (step S1; Yes), the ECU 50 determines whether the accelerator operation unit 36 is not being operated, that is, whether the accelerator opening is closed (step S2). Then, if it is determined in step S2 that the accelerator operation unit 36 is being operated (accelerator ON) (step S2; No), the ECU 50 proceeds with the process to step S5 described later.

[0019] On the other hand, if in step S2 it is determined that the accelerator control unit 36 ​​is not being operated (accelerator OFF) (step S2; Yes), the ECU 50 determines, based on the output value of the humidity sensor 43, whether or not the humidity at the outlet 40b of the evaporator 40 is below a predetermined threshold (step S3). Here, the "predetermined threshold" humidity is, for example, a humidity condition in which condensation does not occur even when the inside of the relay housing 22 is cooled to a predetermined low temperature, when the humidity inside the relay housing 22 is at that threshold humidity.

[0020] In step S3, if it is determined that the humidity at the outlet 40b of the evaporator 40 is below a predetermined threshold (step S3; Yes), the ECU 50 opens the solenoid valve 32 (step S4). In other words, if all the conditions in steps S1 to S3 are met (the engine 35 is running, the accelerator control unit 36 ​​is being operated, and the humidity at the outlet 40b of the evaporator 40 is below a predetermined threshold), the solenoid valve 32 is opened.

[0021] As a result, the surge tank 30 communicates with the outlet 40b of the evaporator 40 via the relay housing 22. At this time, the engine 35 is running and the accelerator control unit 36 ​​is not being operated, so the inside of the surge tank 30 is under negative pressure, which is lower than atmospheric pressure. Therefore, the inside of the relay housing 22 is scavenged by the dry air from the outlet 40b of the evaporator 40, and the inside of the relay housing 22 is filled with dry air. The scavenged air is burned in the engine 35 through the surge tank 30.

[0022] On the other hand, in step S3, if it is determined that the humidity at the outlet 40b of the evaporator 40 is not below a predetermined threshold (step S3; No), the ECU 50 closes the solenoid valve 32 (step S5). In other words, if any one of the conditions in steps S1 to S3 is not satisfied, the solenoid valve 32 is closed. If the solenoid valve 32 is already closed, that closed state is maintained. The order in which the decisions are made in steps S1 to S3 is not particularly limited.

[0023] Next, the ECU 50 determines whether or not to terminate the operation control of the relay dehumidifier 1 (step S6). If it determines not to terminate the operation (step S6; No), it proceeds to step S1 described above. Then, if it is determined that the operation control of the relay dehumidifier 1 should be terminated, for example, due to the engine 35 stopping (step S6; Yes), the ECU 50 terminates the operation control of the relay dehumidifier 1.

[0024] As described above, according to this embodiment, the relay housing 22 is individually connected to the surge tank 30 and the evaporator 40, and a solenoid valve 32 is located in the first connecting pipe 31 that connects the surge tank 30 and the relay housing 22. This solenoid valve 32 is normally closed and is opened when the surge tank 30 generates negative pressure and the humidity at the outlet 40b of the evaporator 40 is below a predetermined threshold. Therefore, when the solenoid valve 32 is opened, the negative pressure in the surge tank 30 draws in air from inside the relay housing 22, and the dry air from the outlet 40b of the evaporator 40 sweeps the inside of the relay housing 22. As a result, the inside of the relay housing 22 is filled with dry air, which suppresses the occurrence of condensation inside the relay housing 22. Consequently, freezing of the contacts 214 of the mechanical relay 20 can be effectively suppressed.

[0025] Furthermore, according to this embodiment, the inside of the relay housing 22 is periodically swept with dry air in conjunction with the operation of the engine 35 and the evaporator 40. Therefore, especially in the case of long-term use, there is concern about the humidity inside the relay housing 22 rising due to moisture permeation, etc., but such a rise in humidity inside the relay housing 22 can be effectively suppressed.

[0026] Furthermore, according to this embodiment, it is determined that the surge tank 30 generates negative pressure when the engine 35 is operating and the accelerator control unit 36 ​​is not being operated. This allows the surge tank 30 to be suitably used as a negative pressure source.

[0027] Furthermore, according to this embodiment, a check valve 42 is placed in the second connecting pipe 41 that connects the evaporator 40 and the relay housing 22, and the check valve 42 ensures that the flow in the second connecting pipe 41 is limited to one direction only, from the outlet 40b of the evaporator 40 to the inside of the relay housing 22. This prevents backflow of air from the relay housing 22 to the outlet 40b of the evaporator 40.

[0028] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above. For example, in the above embodiment, a surge tank was described as an example of a negative pressure source according to the present invention. However, the negative pressure source according to the present invention is not limited to a surge tank as long as it generates negative pressure, and may be, for example, a cooling fan for a radiator. In this case, the condition for the cooling fan to generate negative pressure (the condition corresponding to steps S1 and S2 above) is whether or not the cooling fan is running.

[0029] Furthermore, in the above embodiment, an ECU 35 that electronically controls the engine 35 was described as an example of a valve control unit according to the present invention. However, the valve control unit according to the present invention may be a separate unit from the ECU 35.

[0030] Furthermore, although the above embodiment described the case where there is one mechanical relay 20, the number of mechanical relays 20 is not particularly limited. When there are multiple mechanical relays 20, each of the multiple mechanical relays 20 is individually connected to the surge tank (negative pressure source) and the evaporator, and its operation is individually controlled. Furthermore, details shown in the above embodiments can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0031] 1. Relay dehumidifier 20 Mechanical Relays 21 Mechanical relay body 22 Relay enclosure 30. Surge tank (negative pressure source) 31 1st communication pipe 32 Solenoid valve (valve) 35 Engine 36 Accelerator control unit 40 Evaporator 40b exit 41 2nd communication pipe 42 Check valve 43 Humidity Sensor 50 ECU (Valve Control Unit) 100 vehicles

Claims

1. A relay housing that houses the mechanical relay body and is individually connected to the negative pressure source and the evaporator, A valve is positioned in a first connecting pipe that connects the negative pressure source and the relay housing, It comprises a valve control unit, The valve control unit, The valve is normally closed. The valve is opened when the negative pressure source generates negative pressure and the humidity at the outlet of the evaporator is below a predetermined value. A relay dehumidifier for a vehicle characterized by the following features.

2. The aforementioned negative pressure source is a surge tank. The relay dehumidifier for a vehicle according to feature 1.

3. The valve control unit determines that the negative pressure source generates negative pressure when the engine is running and the accelerator pedal is not being operated. The relay dehumidifier for a vehicle according to feature 2.

4. A check valve is provided in a second connecting pipe that connects the evaporator and the relay housing, and which restricts the flow in the second connecting pipe to only one direction, from the outlet of the evaporator to the inside of the relay housing. The relay dehumidifier for a vehicle according to feature 1.

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