Air supply system, method for controlling air supply system, and computer program product

Abstract

The invention provides an air supply system, a control method of the air supply system, and a computer program product capable of reducing the load of a compressor at the start of operation. The air supply system is provided with: an air drying circuit which is provided between a compressor for delivering compressed air and an air tank for storing compressed dry air, and which has a filter containing a desiccant for capturing moisture; and an ECU that controls the air drying circuit. An ECU is provided with: a supply operation in which compressed air sent from a compressor passes through a filter and compressed dry air is stored in a gas tank; and a regeneration operation in which the compressed dry air stored in the gas tank passes through the filter in the reverse direction and the drain that has passed through the filter is discharged from the drain discharge port, and the ECU executes a compressor assist operation after executing the regeneration operation. The compressor assists the compressed dry air stored in the air tank to be filled in the air drying circuit through the filter in the reverse direction.

Description

[0001] This application is a divisional application of a Chinese invention patent application filed on February 25, 2020, with application number 202080030156.8 (PCT / JP2020 / 007464), and invention name “Air supply system, control method of air supply system, and control program of air supply system”. Technical Field

[0002] The present disclosure relates to an air supply system, a control method of the air supply system, and a control program of the air supply system. Background Art

[0003] In vehicles such as trucks, buses, and construction machinery, compressed air delivered from a compressor is used to control air pressure systems including brake systems and suspension systems. The compressed air contains moisture contained in the atmosphere and liquid impurities such as oil used to lubricate the compressor. If compressed air containing a large amount of moisture and oil enters the air pressure system, it may cause rust and swelling of rubber components, which may cause malfunction. Therefore, a compressed air drying device for removing impurities such as moisture and oil in the compressed air is provided downstream of the compressor.

[0004] The compressed air drying device includes a desiccant and various valves. The compressed air drying device performs a load operation (dehumidification operation) of removing moisture and the like from the compressed air. The compressed dry air generated by the dehumidification operation is stored in a storage unit. In addition, the purification function of the compressed air drying device decreases according to the amount of compressed dry air passing through. Therefore, the compressed air drying device performs an unloading operation (regeneration operation) as follows: the oil and moisture adsorbed on the desiccant are removed from the desiccant and the discharge valve is opened to discharge the removed oil and moisture as drainage (for example, refer to Patent Document 1).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-201323 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] In addition, in some compressed air drying devices, when the pressure between the compressor and the desiccant is reduced by opening the discharge valve to discharge the compressed air between the compressor and the desiccant, the difference between the pressure on the compressor side and the pressure on the desiccant side increases, thereby increasing the load on the compressor during operation.

[0010] An object of the present disclosure is to provide an air supply system and a control method of the air supply system that can reduce the load of a compressor at the start of operation.

[0011] Solutions for solving problems

[0012] An air supply system for solving the above-mentioned problems comprises: an air drying circuit, which is arranged between a compressor that uses engine power as a driving source to deliver compressed air and an air tank that stores compressed dry air, the air drying circuit having a filter including a desiccant that captures moisture; and a control device, which controls the air drying circuit, wherein the control device is configured to: perform a supply action, the supply action being an action of causing the compressed air delivered from the compressor to pass through the filter to store the compressed dry air in the air tank, perform a regeneration action, the regeneration action being an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to discharge the fluid that has passed through the filter from a discharge port, and perform a filling action after performing the regeneration action, the filling action being an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to fill the compressed dry air into the air drying circuit.

[0013] A control method for an air supply system for solving the above-mentioned problem, the air supply system comprising: an air drying circuit, which is arranged between a compressor that uses engine power as a driving source to deliver compressed air and an air tank that stores compressed dry air, the air drying circuit having a filter including a desiccant that captures moisture; and a control device, which controls the air drying circuit, in which the control device performs the following processing: performing a supply action, the supply action being an action of causing the compressed air delivered from the compressor to pass through the filter to store the compressed dry air in the air tank, performing a regeneration action, the regeneration action being an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to discharge the fluid that has passed through the filter from a discharge port, and performing a filling action after performing the regeneration action, the filling action being an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to fill the compressed dry air into the air drying circuit.

[0014] A control program for an air supply system for solving the above-mentioned problem, the air supply system comprising: an air drying circuit, which is arranged between a compressor that uses engine power as a driving source to deliver compressed air and an air tank that stores compressed dry air, the air drying circuit having a filter including a desiccant that captures moisture; and a control device that controls the air drying circuit, the control program of the air supply system causing the control device to function as the following parts: a supply action execution unit that executes a supply action, wherein the supply action is an action of causing the compressed air delivered from the compressor to pass through the filter to store the compressed dry air in the air tank, a regeneration action execution unit that executes a regeneration action, wherein the regeneration action is an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to discharge the fluid that has passed through the filter from a discharge port, and a filling action execution unit that executes a filling action after the regeneration action is executed, wherein the filling action is an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to fill the compressed dry air into the air drying circuit.

[0015] According to the above structure, after the regeneration operation is performed, the filling operation of filling the compressed dry air stored in the air tank into the air drying circuit is performed. Therefore, the pressure of the air drying circuit that has become atmospheric pressure due to the regeneration operation can be made higher than the atmospheric pressure by the filling operation. As a result, the load of the compressor at the start of operation can be reduced.

[0016] Regarding the above-mentioned air supply system, the control device may be configured to: after performing the regeneration action, perform the filling action when the engine is stopped, and perform an engine start-up assist action of stopping the compressor by sending an air pressure signal to the compressor when the engine is restarted.

[0017] According to the above structure, when the engine is stopped, a filling operation is performed to fill the compressed dry air stored in the air tank into the air drying circuit, and when the engine is restarted, an engine start assist operation is performed to stop the compressor. Therefore, the pressure of the air drying circuit that has become atmospheric pressure due to the regeneration action is made higher than the atmospheric pressure by the filling operation, thereby reducing the load of the compressor at the start of operation and the load at the start of the engine. Therefore, the fuel consumption rate can be reduced.

[0018] Regarding the above-mentioned air supply system, the control device may be configured to: perform a purging action, wherein the purging action is an action of allowing the compressed dry air of the air drying circuit to pass through the filter in the reverse direction to discharge the fluid passing through the filter from the exhaust port, and the filling action is performed after performing the purging action.

[0019] According to the above structure, after the purging operation is performed, the filling operation of filling the compressed dry air stored in the air tank into the air drying circuit is performed. Therefore, the pressure of the air drying circuit that has become atmospheric pressure due to the purging operation can be made higher than the atmospheric pressure by the filling operation. Therefore, the load of the compressor at the start of operation can be reduced.

[0020] Regarding the above-mentioned air supply system, the control device may be configured to: after performing the purging action, perform the filling action when the engine is stopped, and perform an engine starting assistance action to stop the compressor by sending an air pressure signal to the compressor when the engine is restarted.

[0021] According to the above structure, after the purging action is performed, when the engine is stopped, a filling action is performed to fill the compressed dry air stored in the air tank into the air drying circuit, and when the engine is restarted, an engine start assist action is performed to stop the compressor. Therefore, the pressure of the air drying circuit that has become atmospheric pressure due to the purging action is made higher than the atmospheric pressure by the filling action, thereby reducing the load of the compressor at the start of operation and the load at the start of the engine. Therefore, the fuel consumption rate can be reduced.

[0022] Regarding the above-mentioned air supply system, the control device may be configured to: after executing the filling action, execute a non-purge supply stop action of stopping the compressor by sending an air pressure signal to the compressor while stopping the discharge of the fluid from the discharge port.

[0023] According to the above configuration, after the filling operation of filling the air drying circuit with compressed air is performed, the compressor is stopped while the pressure of the air drying circuit is maintained, so that the load on the compressor at the start of operation can be reduced.

[0024] Regarding the above-mentioned air supply system, the control device may be configured to: perform a regeneration supply action after performing the no-purge supply stop action, and the regeneration supply action is an action of driving the compressor to send the compressed air to the filter and thereby supply the compressed air to the air tank when the engine is in a no-load state.

[0025] During the regeneration supply operation, the compressor is driven when the engine is in a no-load state, so it is desirable to minimize the load on the compressor. Therefore, according to the above structure, after the no-purge supply stop operation of stopping the compressor is performed while maintaining the pressure of the air drying circuit, the regeneration supply operation is performed. Therefore, the load of the compressor at the start of operation when the engine is in a no-load state can be reduced.

[0026] In the air supply system, the control device may be configured to execute the non-purge supply stop operation when the regeneration supply operation is performed for a predetermined time.

[0027] According to the above configuration, after the regeneration supply operation is performed for a predetermined time, the non-purge supply stop operation is performed to stop the compressor while maintaining the pressure of the air drying circuit. Therefore, the load on the compressor at the start of operation can be reduced.

[0028] Regarding the above-mentioned air supply system, it may be that it also includes: a discharge valve, which connects the branch road connected to the air drying circuit with the discharge port; a regeneration control valve, which switches between a flow in a forward direction from the filter toward the gas tank and a flow in a reverse direction from the gas tank toward the filter; and a compressor control valve, which sends an air pressure signal for stopping the compressor. It may be that the control device is configured to control the discharge valve, the regeneration control valve and the compressor control valve.

[0029] According to the above configuration, each regeneration operation can be performed by controlling the discharge valve, the regeneration control valve, and the compressor control valve by the control device.

[0030] An air supply system comprises: an air drying circuit, which is arranged between a compressor that sends out compressed air by power transmitted from a driving source and an air tank that stores compressed dry air, the air drying circuit having a filter including a desiccant that captures moisture; and a control device that controls the air drying circuit, wherein the control device is configured to: perform a supply action, which is an action of causing the compressed air sent out from the compressor to pass through the filter to store the compressed dry air in the air tank, perform a regeneration action, which is an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to discharge the fluid that has passed through the filter from a discharge port, and after performing the regeneration action, perform a filling action when the compressor is in a non-operating state in which air is not compressed, which is an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to fill the compressed dry air into the air drying circuit, thereby reducing the load of the compressor at the start of operation.

[0031] A control method for an air supply system, the air supply system comprising: an air drying circuit provided between a compressor that delivers compressed air by power transmitted from a driving source and an air tank that stores compressed dry air, the air drying circuit having a filter including a desiccant that captures moisture; and a control device that controls the air drying circuit, wherein the control device is configured to perform the following processing: performing a supply action, the supply action being an action of causing the compressed air delivered from the compressor to pass through the filter to store the compressed dry air in the air tank, performing a regeneration action, the regeneration action being an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to discharge fluid that has passed through the filter from a discharge port, and performing a filling action after the regeneration action is performed when the compressor is in a non-operating state where air is not compressed, the filling action being an action of causing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to fill the compressed dry air into the air drying circuit, thereby reducing the load of the compressor at the start of operation.

[0032] A computer program product, comprising a control program for an air supply system, the air supply system comprising: an air drying circuit, which is provided between a compressor that delivers compressed air by power transmitted from a driving source and an air tank that stores compressed dry air, the air drying circuit having a filter including a desiccant that captures moisture; and a control device that controls the air drying circuit, the control program for the air supply system causing the control device to function as the following units: a supply action execution unit that executes a supply action, the supply action being to cause the compressed air delivered from the compressor to pass through the filter to dry the compressed dry air An action stored in the gas tank, a regeneration action execution unit, which executes the regeneration action, wherein the regeneration action is an action of passing the compressed dry air stored in the gas tank through the filter in the reverse direction to discharge the fluid passing through the filter from the exhaust port, and a filling action execution unit, which executes the filling action when the compressor is in a non-working state without compressing air after executing the regeneration action, wherein the filling action is an action of passing the compressed dry air stored in the gas tank through the filter in the reverse direction to fill the compressed dry air into the air drying circuit, thereby reducing the load of the compressor at the start of operation.

[0033] Effects of the Invention

[0034] According to the present disclosure, the load on the compressor at the start of operation can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1This is a structural diagram showing a schematic structure of one embodiment of an air supply system.

[0036] Figure 2A It is shown Figure 1 FIG. 1 shows a first operation mode and a seventh operation mode of an air drying circuit according to an embodiment of the present invention. Figure 2B It is shown Figure 1 FIG. 1 is a diagram of a second operating mode of an air drying circuit of an embodiment of the present invention, Figure 2C It is shown Figure 1 FIG. 3 is a diagram of a third operation mode and an eighth operation mode of an air drying circuit according to an embodiment of the present invention, Figure 2D It is shown Figure 1 FIG. 4 is a diagram of a fourth operation mode of the air drying circuit of an embodiment of the present invention, Figure 2E It is shown Figure 1 FIG. 5 is a diagram of a fifth operation mode and a ninth operation mode of an air drying circuit according to an embodiment of the present invention, Figure 2F It is shown Figure 1 FIG. 6 is a diagram of a sixth operation mode of the air drying circuit of an embodiment of the present invention.

[0037] Figure 3 It is shown Figure 1 A migration diagram showing the migration of the action of the air drying circuit of an embodiment.

[0038] Figure 4 It is shown Figure 1 Flowchart of the migration of the air drying circuit from the first operation mode according to an embodiment of the present invention.

[0039] Figure 5 It is shown Figure 1 Flow chart of the transition of the air drying circuit from the second operation mode and the third operation mode according to the embodiment.

[0040] Figure 6 It is shown Figure 1 Flowchart of the migration of the air drying circuit from the fifth operation mode in an embodiment.

[0041] Figure 7 It is shown Figure 1 Flow chart of the migration of the air drying circuit from the seventh operation mode in an embodiment.

[0042] Figure 8 It is shown Figure 1 Flow chart of the migration of the air drying circuit from the eighth operation mode in an embodiment.

[0043] Fig. 9 1 is a flowchart showing the transition of the air drying circuit from the ninth operation mode according to this embodiment.

[0044] Fig.101 is a flowchart showing the transition of the air drying circuit from the tenth operation mode according to this embodiment. DETAILED DESCRIPTION

[0045] Reference Figures 1 to 8 , an embodiment of the air supply system is described below. The air supply system is mounted on vehicles such as trucks, buses, and construction machinery. The compressed dry air supplied by the air supply system is used in air compression equipment such as the brake system mounted on the vehicle.

[0046] <Air supply system 10>

[0047] Reference Figure 1 The air supply system 10 will be described. The air supply system 10 includes a compressor 4, an air drying circuit 11, and an ECU (Electronic Control Unit) 80 as a control device.

[0048] ECU 80 is connected to the air drying circuit 11 via a plurality of wirings E61 to E67. ECU 80 includes a computing unit, a communication interface unit, a volatile storage unit, and a non-volatile storage unit. The computing unit is a computer processor configured to control the air drying circuit 11 according to an air supply program stored in a non-volatile storage unit (storage medium). The computing unit may implement at least a portion of the processing performed by itself through a circuit such as an ASIC. The air supply program may be executed by one computer processor or by a plurality of computer processors. In addition, ECU 80 includes a storage unit 80A which stores the results of the operation of the air drying circuit 11. The storage unit 80A is a non-volatile storage unit or a volatile storage unit, and may be the same as or different from the storage unit storing the above-mentioned control program.

[0049] The ECU 80 is connected to other ECUs (not shown) mounted on the vehicle, such as the engine ECU and the brake ECU, via an in-vehicle network such as a CAN (Controller Area Network). The ECU 80 obtains information indicating the vehicle status from these ECUs. The information indicating the vehicle status includes, for example, information indicating whether the ignition switch is turned off, the vehicle speed, and engine driving information.

[0050] The state of the compressor 4 is switched between an operating state (load operation) of compressing air and delivering the air and a non-operating state (idle operation) of not compressing air based on a command value from the ECU 80. The compressor 4 is operated by power transmitted from a rotational drive source such as an engine.

[0051] The air drying circuit 11 is a so-called air dryer. The air drying circuit 11 is connected to the ECU 80 and removes moisture and the like contained in the compressed air from the compressor 4 in load operation. The air drying circuit 11 sends the dried compressed air (hereinafter, compressed dry air) to the supply circuit 12. The compressed dry air supplied to the supply circuit 12 is stored in the air tank 30.

[0052] The compressed dry air stored in the air tank 30 is supplied to air compressor equipment such as the brake system mounted on the vehicle. For example, when the frequency of brake operation is high, such as when the vehicle is traveling downhill or in an urban area, the consumption of the compressed dry air stored in the air tank 30 increases. On the contrary, when the frequency of brake operation is low, the consumption of the compressed dry air stored in the air tank 30 decreases.

[0053] The air drying circuit 11 has a maintenance port P12. The maintenance port P12 is a port for supplying air to the air drying circuit 11 during maintenance.

[0054] <Air drying circuit 11>

[0055] In the housing 11A of the air drying circuit 11 (see Figure 2A ) is provided with a filter 17 inside. The filter 17 is provided in the middle of the air supply passage 18 connecting the compressor 4 and the supply circuit 12. In addition, the filter 17 includes a desiccant. In addition, the filter 17 may include an oil capture part for capturing oil in addition to the desiccant. The oil capture part can be any foam such as polyurethane foam, a metal material with a plurality of vents, a glass fiber filter, etc., which can capture oil while allowing air to pass through.

[0056] The filter 17 allows the compressed air sent from the compressor 4 to pass through a desiccant, thereby removing the moisture contained in the compressed air to dry the compressed air. In addition, the desiccant or oil capture unit captures the oil contained in the compressed air to purify the compressed air. The compressed air passing through the filter 17 is supplied to the supply circuit 12 via the downstream one-way valve 19, and the downstream one-way valve 19 serves as a check valve that only allows air to flow downstream relative to the filter 17. That is, when the filter 17 side is set to the upstream and the supply circuit 12 side is set to the downstream, the downstream one-way valve 19 only allows air to flow from the upstream to the downstream. In addition, the downstream one-way valve 19 has a specified valve opening pressure (closing pressure), so when the compressed air flows, the pressure upstream is higher than the pressure downstream by the valve opening pressure.

[0057] In addition, a bypass flow path 20 is provided downstream of the filter 17 in parallel with the downstream check valve 19 as a bypass path for bypassing the downstream check valve 19. The bypass flow path 20 is provided with a regeneration control valve 21.

[0058] The regeneration control valve 21 is a solenoid valve controlled by the ECU 80. The ECU 80 controls the power supply of the regeneration control valve 21 to be turned on / off (driven / non-driven) via the wiring E64, thereby switching the operation of the regeneration control valve 21. The regeneration control valve 21 closes the valve to block the bypass flow path 20 when the power supply is turned off, and opens the valve to connect the bypass flow path 20 when the power supply is turned on. For example, the ECU 80 receives the value of the air pressure in the gas tank 30, and operates the regeneration control valve 21 when the value of the air pressure exceeds a predetermined range.

[0059] A throttle hole 22 is provided in the bypass flow path 20 between the regeneration control valve 21 and the filter 17. When the regeneration control valve 21 is energized, the compressed dry air on the supply circuit 12 side is delivered to the filter 17 via the bypass flow path 20 in a state where the flow rate is limited by the throttle hole 22. The compressed dry air delivered to the filter 17 flows back in the filter 17 from downstream to upstream and passes through the filter 17. Such a process is an action to regenerate the filter 17, which is called a regeneration action of the dryer. At this time, the compressed dry air delivered to the filter 17 is the dried and purified air supplied to the supply circuit 12 from the air supply passage 18 through the filter 17, etc., so that the moisture and oil captured by the filter 17 can be removed from the filter 17. In normal control, the ECU 80 opens the regeneration control valve 21 when the pressure in the air tank 30 reaches the upper limit value (cut-out pressure). On the other hand, when the pressure in the gas tank 30 reaches the lower limit value (cut-in pressure), the regeneration control valve 21 that has been opened is closed.

[0060] A branch passage 16 branches off from a portion between the compressor 4 and the filter 17. The branch passage 16 is provided with a waste liquid discharge valve 25, and a waste liquid discharge port 27 is connected to the terminal end of the branch passage 16.

[0061] The drain liquid, which is a fluid containing water and oil removed from the filter 17, is transported to the drain liquid discharge valve 25 together with the compressed air. The drain liquid discharge valve 25 is an air pressure driven valve driven by air pressure, and is provided between the filter 17 and the drain liquid discharge port 27 in the branch passage 16. The drain liquid discharge valve 25 is a two-position two-way valve that changes its position between a closed valve position and an open valve position. When the drain liquid discharge valve 25 is in the open valve position, the drain liquid is transported to the drain liquid discharge port 27. The drain liquid discharged from the drain liquid discharge port 27 can also be recovered by an oil separator not shown. In addition, the drain liquid is equivalent to the fluid that has passed through the filter 17 in the reverse direction.

[0062] The drain valve 25 is controlled by the regulator 26A. The regulator 26A is a solenoid valve controlled by the ECU 80. The ECU 80 switches the operation of the regulator 26A by controlling the power on / off (driving / non-driving) of the regulator 26A via the wiring E63. When the power is turned on, the regulator 26A inputs an air pressure signal to the drain valve 25 to open the drain valve 25. In addition, when the power is turned off, the regulator 26A does not input an air pressure signal to the drain valve 25, but opens the drain valve 25 to the atmospheric pressure, thereby closing the drain valve 25.

[0063] The drain valve 25 is maintained in the closed position when no air pressure signal is input from the regulator 26A, and is switched to the open position when an air pressure signal is input from the regulator 26A. In addition, when the pressure of the input port of the drain valve 25 connected to the compressor 4 exceeds the upper limit value, the drain valve 25 is forcibly switched to the open position.

[0064] An upstream check valve 15 is provided between the compressor 4 and the filter 17 and between the compressor 4 and the branch passage 16. When the compressor 4 side is set to the upstream and the filter 17 side is set to the downstream, the upstream check valve 15 only allows air to flow from the upstream to the downstream. The upstream check valve 15 has a specified valve opening pressure (closing pressure), so when the compressed air flows, the pressure upstream is higher than the pressure downstream by the valve opening pressure. In addition, a reed valve at the outlet of the compressor 4 is provided upstream of the upstream check valve 15. A branch passage 16 and a filter 17 are provided downstream of the upstream check valve 15.

[0065] <Compressor 4>

[0066] The compressor 4 is controlled by the unloading control valve 26B. The unloading control valve 26B is a solenoid valve controlled by the ECU 80. The ECU 80 switches the action of the unloading control valve 26B by controlling the on / off (driven / non-driven) of the power supply of the unloading control valve 26B via the wiring E62. When the power supply is cut off, the unloading control valve 26B is switched to the open position to open the flow path between the unloading control valve 26B and the compressor 4 to the atmosphere. In addition, when the power supply is turned on, the unloading control valve 26B is switched to the supply position to deliver an air pressure signal composed of compressed air to the compressor 4. In addition, the unloading control valve 26B functions as a compressor control valve.

[0067] When an air pressure signal is input from the unloading control valve 26B, the state of the compressor 4 is switched to a non-operating state (idling). For example, when the pressure of the supply circuit 12 reaches the cut-out pressure, it is not necessary to supply compressed dry air. When the pressure on the supply circuit 12 side reaches the cut-out pressure and the ECU 80 turns on the power of the unloading control valve 26B (drives the unloading control valve 26B), the unloading control valve 26B switches to the supply position. As a result, an air pressure signal is supplied from the unloading control valve 26B to the compressor 4, and the state of the compressor 4 is switched to a non-operating state.

[0068] <Sensor>

[0069] A pressure sensor 50 is provided between the compressor 4 and the upstream check valve 15. The pressure sensor 50 is connected to the air supply passage 18 to measure the air pressure of the air supply passage 18 and transmits the measured result to the ECU 80 via the wiring E61.

[0070] A humidity sensor 51 and a temperature sensor 52 are provided between the downstream check valve 19 and the supply circuit 12. The humidity sensor 51 measures the humidity of the compressed dry air downstream of the filter 17, and outputs the measured result to the ECU 80 via the wiring E65. The temperature sensor 52 measures the temperature of the compressed dry air downstream of the filter 17, and outputs the measured result to the ECU 80 via the wiring E66. The ECU 80 determines the dryness state of the compressed dry air based on the humidity and temperature of the compressed dry air input from the humidity sensor 51 and the temperature sensor 52. That is, the humidity and temperature of the compressed dry air are indicators indicating the dryness state of the compressed dry air.

[0071] ECU 80 calculates the amount of moisture in the supply air based on the humidity and temperature when the compressed dry air is supplied to the gas tank 30, and calculates a reference amount of moisture in the tank air based on the humidity and temperature during regeneration when the compressed dry air is reversed from the gas tank 30. The amount of moisture in the tank air is calculated based on formula (1). In addition, the amount of moisture in the supply air is the amount of moisture sent to the gas tank 30 during supply, and can be calculated based on the humidity and temperature during supply and the amount of supply air between supply cycles. The reference amount of moisture in the tank air is the amount of moisture present in the gas tank 30 when the moisture amount is updated, and can be calculated based on the humidity and temperature during regeneration or the amount of moisture in the tank air. The amount of moisture in the consumed air is the amount of moisture sent from the gas tank 30 due to the consumption of the compressed dry air, and can be calculated based on the amount of moisture in the tank air and the amount of consumed air between consumption cycles.

[0072] (amount of water contained in the tank air) = (base amount of water contained in the tank air) + (change in amount of water contained in the tank air) (1)

[0073] (Change in water content in tank air) = (Water content in supply air) - (Water content in consumed air)

[0074] Furthermore, a pressure sensor 53 is provided between the downstream check valve 19 and the supply circuit 12. The pressure sensor 53 is provided, for example, to detect the air pressure in the gas tank 30 storing compressed dry air, and is connected to the ECU 80 via the wiring E67. The pressure between the downstream check valve 19 and the supply circuit 12 is the same as the pressure in the gas tank 30, and the detection result of the pressure sensor 53 can be used as the pressure in the gas tank 30. In addition, the pressure sensor 53 can be provided in the supply circuit 12, and can also be provided in the gas tank 30.

[0075] <Description of Operation of Air Drying Circuit 11>

[0076] like Figure 2A to Figure 2F As shown, the air drying circuit 11 has a plurality of operation modes including at least a first operation mode to an eighth operation mode.

[0077] (First action mode)

[0078] like Figure 2A As shown, the first action mode is a mode for performing a "supply" action, which performs normal dehumidification (load). In the first action mode, the regeneration control valve 21 and the unloading control valve 26B are closed (recorded as "CLOSE" in the figure), and the regulator 26A is set to an open position (recorded as "CLOSE" in the figure) in which an air pressure signal is not input to the drain valve 25. At this time, no power is supplied to the regeneration control valve 21, the regulator 26A, and the unloading control valve 26B. In addition, the regulator 26A and the unloading control valve 26B open the ports of the compressor 4 connected to their downstream and the ports of the drain valve 25 to the atmosphere. In the first action mode, when compressed air is supplied from the compressor 4 (recorded as "ON" in the figure), the compressed air is supplied to the supply circuit 12 after the moisture and the like are removed by the filter 17.

[0079] (Second action mode)

[0080] like Figure 2BAs shown in FIG. 1 , the second operation mode is a mode for performing a "purge" operation of passing the compressed dry air in the air drying circuit 11 through the filter 17 to purify the filter 17. In this second operation mode, the regeneration control valve 21 is closed, and the regulator 26A and the unloading control valve 26B are opened (represented as "OPEN" in the figure). At this time, power is supplied to the regulator 26A and the unloading control valve 26B, respectively, and the port of the compressor 4 and the port of the drain discharge valve 25 connected to the downstream of them are connected to the upstream (supply circuit 12 side) respectively. As a result, the compressor 4 is switched to a non-operating state (represented as "OFF" in the figure), and the drain discharge valve 25 is opened. As a result, the compressed dry air between the downstream check valve 19 and the filter 17 flows through the filter 17 in the opposite direction to the air flow in the first operation mode (supply) (counterflow), and the moisture captured by the filter 17 is discharged from the drain discharge port 27 as drain. In addition, the air pressure of the filter 17 and the air supply passage 18 is opened to atmospheric pressure.

[0081] (Third Action Mode)

[0082] like Figure 2C As shown in FIG. 1 , the third operation mode is a mode for performing a "regeneration" operation for regenerating the filter 17. In the third operation mode, the regeneration control valve 21 and the unloading control valve 26B are opened, and the regulator 26A is set to the input position. At this time, in addition to supplying power to the regulator 26A and the unloading control valve 26B, power is also supplied to the regeneration control valve 21. In the third operation mode, the compressor 4 is set to a non-operating state, and the compressed dry air stored in the supply circuit 12 or the gas tank 30 is reversed through the filter 17 and discharged from the drain outlet 27. Thus, the moisture captured by the filter 17 is removed. The second operation mode and the third operation mode are both modes for purifying the filter 17, but the third operation mode is different from the second operation mode at least in that the regeneration control valve 21 is opened. Thus, in the third operation mode, the compressed dry air in the gas tank 30 can pass through the filter 17 via the supply circuit 12 and the bypass flow path 20. Therefore, the effect of purifying the filter 17 is higher than that in the second operation mode. Furthermore, in the third operation mode, the air pressure of the filter 17 and the air supply passage 18 is also released to the atmospheric pressure.

[0083] (Fourth Action Mode)

[0084] like Figure 2DAs shown in FIG. 1 , the fourth operation mode is a mode in which a "de-oiling" operation is performed to discharge the compressed air supplied from the compressor 4 while the compressor 4 is operated. When the compressor 4 is in a non-operating state, oil may accumulate in the compression chamber of the compressor 4. If the state of the compressor 4 is switched to an operating state while oil accumulates in the compression chamber, the amount of oil contained in the compressed air delivered from the compression chamber may increase. The de-oiling operation is performed for the purpose of discharging the compressed air with excessive oil through the drain valve 25 to reduce the load on the filter 17. In the fourth operation mode, the regeneration control valve 21 and the unloading control valve 26B are closed, and the regulator 26A is closed after the valve is opened for a fixed period. In the fourth operation mode, when the state of the compressor 4 is in an operating state, the compressed air supplied from the compressor 4 is discharged from the drain outlet 27 for a fixed period. Therefore, it is possible to suppress the increase in the amount of water and oil captured by the filter 17 immediately after the compressor 4 is switched from the non-operating state to the operating state. The de-oiling operation can also be performed when the oil content from the compressor 4 increases, such as when the engine speed increases during operation or when the engine load is high.

[0085] (Fifth Action Mode)

[0086] like Figure 2E As shown in FIG. 1 , the fifth operation mode is a mode for performing a "no-purge supply stop" operation in which the compressor 4 is stopped in a no-purge state when the engine is running. In the fifth operation mode, the regeneration control valve 21 and the regulator 26A are closed, respectively. In the fifth operation mode, the regeneration control valve 21 and the regulator 26A are closed, respectively, and the unloading control valve 26B is opened. In the fifth operation mode, when the compressor 4 is not in operation, the compressed air or compressed dry air remaining in the air supply passage 18 or the desiccant of the filter 17 is not discharged from the drain outlet 27, thereby maintaining the air pressure.

[0087] (Sixth Action Mode)

[0088] like Figure 2FAs shown, the sixth action mode is a mode for performing a "compressor assist" action, and the "compressor assist" action performs a pressurization process. In the sixth action mode, the regeneration control valve 21 and the unloading control valve 26B are opened respectively, and the regulator 26A is set to the open position. In the sixth action mode, when the compressor 4 is in a non-operating state, the compressed air of the supply circuit 12 is supplied (backflow) to the air supply passage 18 and the desiccant of the filter 17, thereby making the pressure of the air supply passage 18 and the filter 17 higher than the atmospheric pressure, so that the back pressure (air pressure) of the upstream check valve 15 is maintained at a pressure higher than the atmospheric pressure. In this way, the generation of negative pressure in the cylinder can be suppressed, thereby reducing the operating load of the compressor 4 during idling. Specifically, when the compressor 4 is in idling, the drain discharge valve 25 is closed, and the air pressure in the desiccant of the filter 17 and the air supply passage 18 is maintained at a pressure higher than the atmospheric pressure by the compressed air supplied by the compressor 4. In addition, the sixth action mode is equivalent to the filling action.

[0089] (Seventh Action Mode)

[0090] like Figure 2A As shown in FIG. 1 , the seventh operation mode is a mode for performing a "regeneration supply" operation, which performs dehumidification (load) during regeneration driven by the compressor 4 when the engine is in an unloaded state. In the seventh operation mode, similarly to the first operation mode, the regeneration control valve 21, the regulator 26A, and the unloading control valve 26B are closed (represented as "CLOSE" in the figure).

[0091] (Eighth Action Mode)

[0092] like Figure 2C As shown, the eighth operation mode is a mode for performing a "forced regeneration" operation for forcibly regenerating the filter 17. In the eighth operation mode, similarly to the third operation mode, the regeneration control valve 21, the regulator 26A, and the unloading control valve 26B are opened.

[0093] (Ninth Action Mode)

[0094] like Figure 2E As shown in FIG. 1 , the ninth operation mode is a mode for performing an "engine start assist" operation in which the compressor 4 is stopped without purging when the engine is restarted. In the ninth operation mode, the regeneration control valve 21 and the regulator 26A are closed, respectively, and the unloading control valve 26B is opened. In the ninth operation mode, when the compressor 4 is not in operation, the compressed air or compressed dry air remaining in the air supply passage 18 or the desiccant of the filter 17 is not discharged from the drain outlet 27, thereby maintaining the air pressure.

[0095] (Tenth Action Mode)

[0096] The tenth operation mode is a mode for performing a "decompression" operation of efficiently performing the compressor-assisted operation by reducing the pressure in the air drying circuit 11 and the filter 17 to the optimum pressure. In the tenth operation mode, the regeneration control valve 21 is closed and the regulator 26A is set to the open position. As a result, the drain valve 25 is opened. In the tenth operation mode, the compressed dry air in the air drying circuit 11 and the filter 17 is discharged from the drain valve 25 so that the pressure of the compressed dry air is reduced to a predetermined pressure.

[0097] (Transition of action mode)

[0098] like Figure 3 As shown, the ten operation modes of the air drying circuit 11 are changed based on the respective determinations of the ECU 80 .

[0099] Reference Figures 4 to 10 , explaining the transition from each action mode.

[0100] The ECU 80 performs a supply process for supplying the compressed air outputted from the compressor 4 to the supply circuit 12. The supply process is started in accordance with conditions such as when the engine is driven. In the supply process, the air drying circuit 11 is in the supply (first operation) mode M1.

[0101] like Figure 4 As shown, in the supply (first operation) mode M1, the ECU 80 determines whether the pressure of the supply circuit 12 is higher than the cut-out pressure (step S11). That is, the ECU 80 obtains the pressure of the gas tank 30 detected by the pressure sensor 53 and determines whether the pressure reaches the cut-out pressure.

[0102] Then, when the ECU 80 determines that the pressure of the supply circuit 12 has reached the cut-out pressure (step S11: Yes), it determines whether the moisture content of the gas tank 30 is high (step S12). That is, when the moisture content of the gas tank 30 is equal to or greater than a predetermined value, the ECU 80 needs to regenerate the desiccant of the filter 17, so the ECU 80 determines the moisture content of the gas tank 30.

[0103] Then, when the ECU 80 determines that the moisture content of the gas tank 30 is greater than the specified value (step S12: "Yes"), it transfers to the regeneration (third action) mode M3. The regeneration (third action) mode M3 allows the compressed dry air stored in the gas tank 30 to pass through the filter 17, thereby regenerating the desiccant in the filter 17.

[0104] In addition, when the ECU 80 determines that the moisture content of the gas tank 30 is less than the specified value (step S12: "No"), it transfers to the purge (second action) mode M2. The purge (second action) mode M2 ​​allows the compressed dry air between the downstream one-way valve 19 and the filter 17 to pass through the filter 17, and discharges the moisture captured by the filter 17 as exhaust liquid from the exhaust outlet 27.

[0105] On the other hand, when the ECU 80 determines that the pressure of the charge circuit 12 has not reached the cut-out pressure (step S11 : NO), it determines whether the pressure of the charge circuit 12 is equal to or higher than the cut-in pressure (step S13 ).

[0106] Then, when the ECU 80 determines that the pressure of the supply circuit 12 is above the cut-in pressure (step S13: Yes), it determines whether the engine speed is low (step S14). That is, the ECU 80 determines whether the engine speed is reduced to the engine stop level (for example, below several hundred rpm) to prepare for restarting the engine.

[0107] Then, when the ECU 80 determines that the engine speed is high (for example, higher than several hundred rpm) (step S14: No), the process proceeds to step S15.

[0108] On the other hand, when the ECU 80 determines that the engine speed is low (for example, less than several hundred rpm) (step S14: YES), the mode is shifted to the engine start assist (ninth operation) mode M9.

[0109] On the other hand, when the ECU 80 determines that the pressure of the supply circuit 12 is lower than the cut-in pressure (step S13: No), it determines whether the condition for shifting to the de-oiling (fourth operation) mode M4 is satisfied (step S15). That is, the ECU 80 determines whether the passage of a predetermined time, the number of de-oiling operations being less than a predetermined number, and the low operating rate of the compressor 4 are all satisfied as the condition for shifting to the de-oiling (fourth operation) mode M4. Then, when the ECU 80 determines that the condition for shifting to the de-oiling (fourth operation) mode M4 is not satisfied (step S15: No), it returns the process to step S11.

[0110] On the other hand, when ECU 80 determines that the conditions for transferring to deoiling (fourth action) mode M4 are met (step S15: "Yes"), it transfers to deoiling (fourth action) mode M4, and deoiling (fourth action) mode M4 discharges the compressed air supplied from compressor 4 while operating compressor 4.

[0111] After shifting to the degreasing (fourth operation) mode M4, the ECU 80 determines whether a predetermined time has elapsed (step S16). That is, the ECU 80 performs the degreasing (fourth operation) mode M4 for a predetermined time. Then, when the ECU 80 determines that the predetermined time has elapsed (step S16: "Yes"), it shifts to the supply (first operation) mode M1.

[0112] like Figure 5 As shown, in the purge (second operation) mode M2 ​​and the regeneration (third operation) mode M3, the ECU 80 determines whether a predetermined time has elapsed (step S21). That is, the ECU 80 performs the purge (second operation) mode M2 ​​and the regeneration (third operation) mode M3 for a predetermined time.

[0113] Then, when the ECU 80 determines that the predetermined time has not elapsed (step S21: No), it determines whether the pressure of the supply circuit 12 is lower than the cut-in pressure (step S24). That is, the ECU 80 obtains the pressure of the gas tank 30 detected by the pressure sensor 53 to determine whether the pressure has reached the cut-in pressure.

[0114] Then, when the ECU 80 determines that the pressure of the supply circuit 12 has reached the cut-in pressure (step S24: Yes), the ECU 80 shifts to the supply (first operation) mode M1 because the compressed dry air is insufficient. On the other hand, when the ECU 80 determines that the pressure of the supply circuit 12 has not reached the cut-in pressure (step S24: No), the processing returns to step S21.

[0115] On the other hand, when the ECU 80 determines that the predetermined time has elapsed (step S21: Yes), it determines whether or not the compressor assist (sixth operation) process is enabled (step S22).

[0116] Then, when the ECU 80 determines that the compressor assist (sixth action) processing is set to be invalid (step S22: "No"), it shifts to the non-purge supply stop (fifth action) mode M5, and the non-purge supply stop (fifth action) mode M5 stops the compressor 4 in a non-purge state.

[0117] When the ECU 80 determines that the compressor assist (sixth operation) process is enabled (step S22: YES), the ECU 80 shifts to the compressor assist (sixth operation) mode M6 in which the pressurizing process is performed.

[0118] After the transition to the compressor assist (sixth operation) mode M6, the ECU 80 determines whether a predetermined time has elapsed (step S23). That is, the ECU 80 performs the compressor assist (sixth operation) mode M6 for a predetermined time. Then, when the ECU 80 determines that the predetermined time has elapsed (step S23: Yes), it transitions to the non-purge supply stop (fifth operation) mode M5.

[0119] like Figure 6 As shown, in the non-purge supply stop (fifth operation) mode M5, the ECU 80 determines whether the pressure of the supply circuit 12 is lower than the cut-in pressure (step S31). That is, the ECU 80 obtains the pressure of the gas tank 30 detected by the pressure sensor 53 and determines whether the pressure reaches the cut-in pressure.

[0120] Then, when the ECU 80 determines that the pressure of the charge circuit 12 has reached the cut-in pressure (step S31 : YES), the ECU 80 shifts to the charge (first operation) mode M1 because the compressed dry air is insufficient.

[0121] On the other hand, when the ECU 80 determines that the pressure of the supply circuit 12 has not reached the cut-in pressure (step S31: No), it determines whether the condition for shifting to the regenerative supply (seventh action) mode M7 is satisfied (step S32). That is, the ECU 80 determines whether the vehicle is running, no fuel is consumed, and the pressure of the supply circuit 12 is less than the threshold value are all satisfied as the shift condition to the regenerative supply (seventh action) mode M7. Then, when the ECU 80 determines that the condition for shifting to the regenerative supply (seventh action) mode M7 is not satisfied (step S32: No), it returns the process to step S31.

[0122] On the other hand, when the ECU 80 determines that the condition for shifting to the regenerative supply (seventh operation) mode M7 is satisfied (step S32: YES), the ECU 80 shifts to the regenerative supply (seventh operation) mode M7 for performing dehumidification (load) during regeneration.

[0123] like Figure 7 As shown, in the regenerative supply (seventh action) mode M7, the ECU 80 determines whether the condition for shifting to the non-purge supply stop (fifth action) mode M5 is satisfied (step S41). That is, the ECU 80 determines whether at least one of the following conditions is satisfied: the pressure of the supply circuit 12 is higher than the cut-out pressure, a predetermined time has passed, and the fuel consumption of the engine is high, as a condition for shifting to the non-purge supply stop (fifth action) mode M5. Then, when the ECU 80 determines that the condition for shifting to the non-purge supply stop (fifth action) mode M5 is satisfied (step S41: "Yes"), it shifts to the non-purge supply stop (fifth action) mode M5.

[0124] On the other hand, when the ECU 80 determines that the condition for shifting to the non-purge supply stop (fifth operation) mode M5 is not satisfied (step S41: No), it determines whether the pressure of the supply circuit 12 is lower than the cut-in pressure (step S42). That is, the ECU 80 obtains the pressure of the gas tank 30 detected by the pressure sensor 53 to determine whether the pressure reaches the cut-in pressure.

[0125] Then, when the ECU 80 determines that the pressure of the charge circuit 12 has reached the cut-in pressure (step S42: YES), the ECU 80 shifts to the charge (first operation) mode M1 because the compressed dry air is insufficient.

[0126] On the other hand, when the ECU 80 determines that the pressure of the supply circuit 12 has not reached the cut-in pressure (step S42: "No"), it determines whether the condition for shifting to the forced regeneration (eighth action) mode M8 is satisfied (step S43). That is, the ECU 80 determines whether the pressure of the supply circuit 12 is higher than the threshold value and the amount of moisture in the gas tank 30 is high as the condition for shifting to the forced regeneration (eighth action) mode M8. In the regeneration supply (seventh action) mode M7, the ECU 80 determines the dryness of the compressed dry air by the amount of moisture in the tank air in the gas tank 30. That is, the amount of moisture in the tank air in the gas tank 30 is an indicator of the dryness of the compressed dry air. If the amount of moisture in the tank air is greater than the prescribed value, the ECU 80 determines that the amount of moisture in the gas tank 30 is high, and if the amount of moisture in the tank air is less than the prescribed value, the ECU 80 determines that the amount of moisture in the gas tank 30 is low. Then, when the ECU 80 determines that the condition for shifting to the forced regeneration (eighth operation) mode M8 is not satisfied (step S43 : NO), the ECU 80 returns the process to step S42 .

[0127] On the other hand, when the ECU 80 determines that the conditions for shifting to the forced regeneration (eighth action) mode M8 are met (step S43: Yes), it shifts to the forced regeneration (eighth action) mode M8 for forcibly regenerating the filter 17. When the ECU 80 determines that the amount of moisture is high and other conditions are met, it executes the forced regeneration (eighth action) mode M8 for flowing the compressed dry air in the reverse direction.

[0128] like Figure 8 As shown, in the forced regeneration (eighth operation) mode M8, the ECU 80 determines whether a predetermined time has elapsed (step S51). That is, the ECU 80 performs the forced regeneration (eighth operation) mode M8 for a predetermined time.

[0129] When the ECU 80 determines that the predetermined time has not elapsed (step S51: No), it determines whether the pressure of the supply circuit 12 is lower than the cut-in pressure (step S55). That is, the ECU 80 obtains the pressure of the gas tank 30 detected by the pressure sensor 53 and determines whether the pressure has reached the cut-in pressure.

[0130] Then, when the ECU 80 determines that the pressure of the supply circuit 12 has reached the cut-in pressure (step S55: Yes), the ECU 80 shifts to the supply (first operation) mode M1 because the compressed dry air is insufficient. On the other hand, when the ECU 80 determines that the pressure of the supply circuit 12 has not reached the cut-in pressure (step S55: No), the process returns to step S51.

[0131] On the other hand, when the ECU 80 determines that the predetermined time has elapsed (step S51: YES), it determines whether the operating rate of the compressor 4 is high (step S52). That is, the ECU 80 determines whether the load of the compressor 4 when driving is high based on the operating rate of the compressor 4.

[0132] Then, when the ECU 80 determines that the operating rate of the compressor 4 is high (step S52: YES), the compressor assist (sixth operation) is not necessary, and thus the mode is shifted to the supply (first operation) mode M1.

[0133] On the other hand, when the ECU 80 determines that the operating rate of the compressor 4 is low (step S52: No), it determines whether to enable the compressor assist (sixth operation) process to perform the compressor assist (sixth operation) (step S53).

[0134] Then, when the ECU 80 determines that the compressor assist (sixth action) process is set to invalid (step S53: No), it shifts to the non-purge supply stop (fifth action) mode M5. In addition, when the ECU 80 determines that the compressor assist (sixth action) process is set to valid (step S53: Yes), it shifts to the compressor assist (sixth action) mode M6.

[0135] After shifting to the compressor assist (sixth operation) mode M6, the ECU 80 determines whether a predetermined time has elapsed (step S54). That is, the ECU 80 performs the compressor assist (sixth operation) mode M6 for a predetermined time. Then, when the ECU 80 determines that the predetermined time has elapsed (step S54: Yes), it shifts to the non-purge supply stop (fifth operation) mode M5.

[0136] like Fig. 9As shown, in the engine start assist (ninth action) mode M9, the ECU 80 determines whether the pressure of the supply circuit 12 is greater than the cut-in pressure (step S61). Then, when the ECU 80 determines that the pressure of the supply circuit 12 is less than the cut-in pressure (step S61: "No"), it shifts to the supply (first action) mode M1.

[0137] On the other hand, when the ECU 80 determines that the pressure of the supply circuit 12 is equal to or higher than the cut-in pressure (step S61: Yes), it determines whether the engine speed is high (for example, higher than several hundred rpm) (step S62). Then, when the ECU 80 determines that the engine speed is low (for example, lower than several hundred rpm) (step S62: No), it returns to step S61.

[0138] On the other hand, when the ECU 80 determines that the engine speed is high (for example, higher than several hundred rpm) (step S62: YES), the mode is shifted to the non-purge supply stop (fifth operation) mode M5.

[0139] like Fig.10 As shown, in the decompression (tenth action) mode M10, the ECU 80 determines whether the pressure of the charge circuit 12 is lower than the cut-in pressure (step S71). Then, when the ECU 80 determines that the pressure of the charge circuit 12 is lower than the cut-in pressure (step S71: Yes), it shifts to the charge (first action) mode M1.

[0140] On the other hand, when the ECU 80 determines that the pressure of the supply circuit 12 is equal to or higher than the cut-in pressure (step S71: No), it determines whether a predetermined time has passed (step S72). That is, the ECU 80 operates in the decompression (tenth operation) mode M10 for a predetermined time. Then, when the ECU 80 determines that the predetermined time has passed (step S72: Yes), it shifts to the non-purge supply stop (fifth operation) mode M5.

[0141] Next, the effects of this embodiment will be described.

[0142] (1) After regeneration (third action) is performed, compressor assist (sixth action) is performed to fill the compressed dry air stored in the air tank 30 into the air supply passage 18. Therefore, the pressure of the air supply passage 18, which has become atmospheric pressure due to regeneration (third action), can be made higher than the atmospheric pressure by the compressor assist (sixth action). As a result, the load of the compressor 4 at the start of operation can be reduced.

[0143] (2) When the engine is restarted, engine start assistance (ninth action) is performed to stop the compressor 4. Therefore, the pressure of the air supply passage 18 that has become atmospheric pressure due to regeneration (third action) is made higher than the atmospheric pressure by the compressor assist (sixth action), thereby reducing the load of the compressor 4 at the start of operation and the load at the start of the engine. Therefore, the fuel consumption rate can be reduced.

[0144] (3) After the purging (second operation) is performed, the compressor assist (sixth operation) is performed to fill the compressed dry air stored in the air tank 30 into the air supply passage 18. Therefore, the pressure of the air supply passage 18 that has become atmospheric pressure due to the purging (second operation) can be made higher than the atmospheric pressure by the compressor assist (sixth operation). Therefore, the load of the compressor 4 at the start of operation can be reduced.

[0145] (4) When the engine is restarted, engine start assistance (ninth action) is performed to stop the compressor 4. Therefore, by making the pressure of the air supply passage 18, which has become atmospheric pressure due to purging (second action), higher than the atmospheric pressure by the compressor assist (sixth action), the load of the compressor 4 at the start of operation can be reduced, and the load at the start of the engine can be reduced. Therefore, the fuel consumption rate can be reduced.

[0146] (5) After executing the compressor assist (sixth operation) of filling the air supply passage 18 with compressed air, the compressor 4 is stopped while the pressure of the air supply passage 18 is maintained. Therefore, the load on the compressor 4 at the start of operation can be reduced.

[0147] (6) After stopping the compressor 4 without purge supply (fifth operation) while maintaining the pressure of the air supply passage 18, regeneration supply (seventh operation) is performed. Therefore, the load of the compressor 4 at the start of operation when the engine is in an unloaded state can be reduced.

[0148] (7) After regenerative supply is performed for a predetermined time (seventh operation), the compressor 4 is stopped without purge supply (fifth operation) while maintaining the pressure of the air supply passage 18. Therefore, the load on the compressor 4 at the start of operation can be reduced.

[0149] (8) The ECU 80 can control the drain valve 25, the regeneration control valve 21, and the unloading control valve 26B to perform supply (first action), purging (second action), regeneration (third action), degreasing (fourth action), supply stop without purging (fifth action), compressor assistance (sixth action), regeneration supply (seventh action), forced regeneration (eighth action), engine start assistance (ninth action), and decompression (tenth action).

[0150] (Other Embodiments)

[0151] The above-mentioned embodiment can be modified and implemented as follows. The above-mentioned embodiment and the following modified examples can be combined and implemented within the scope of no technical contradiction.

[0152] In the above embodiment, the tank air moisture content is calculated based on the tank air moisture content reference amount, the tank air moisture content change amount, etc. However, the tank air moisture content may be estimated based on the humidity and temperature of the compressed dry air in the gas tank 30 .

[0153] In the above embodiment, the purge (second operation) mode M2, the regeneration (third operation) mode M3, the deoiling (fourth operation) mode M4, the compressor assist (sixth operation) mode M6, the regeneration supply (seventh operation) mode M7, the forced regeneration (eighth operation) mode M8, and the decompression (tenth operation) mode M10 are performed during a predetermined time. However, the predetermined time of each mode may be arbitrarily set.

[0154] In step S15 of the above embodiment, the conditions for shifting to the de-oiling (fourth operation) mode M4 are that all of the conditions are satisfied: the passage of a prescribed time, the number of times the de-oiling is performed is less than the prescribed number of times, and the operating rate of the compressor 4 is low. Alternatively, the ECU 80 may shift to the de-oiling (fourth operation) mode M4 when at least one of the conditions is satisfied. That is, in step S15, the ECU 80 determines whether at least one of the conditions is satisfied: the passage of a prescribed time, the number of times the de-oiling is performed is less than the prescribed number of times, and the operating rate of the compressor 4 is low, as a condition for shifting to the de-oiling (fourth operation) mode M4.

[0155] In step S32 of the above embodiment, the conditions for shifting to the regenerative supply (seventh operation) mode M7 are that the vehicle is running, no fuel is consumed, and the pressure of the supply circuit 12 is less than the threshold value. Alternatively, the ECU 80 may shift to the regenerative supply (seventh operation) mode M7 when at least one of the conditions is met. That is, in step S32, the ECU 80 determines whether at least one of the conditions of the vehicle being running, no fuel is consumed, and the pressure of the supply circuit 12 is less than the threshold value is met as the condition for shifting to the regenerative supply (seventh operation) mode M7.

[0156] In step S43 of the above embodiment, the condition for shifting to the forced regeneration (eighth action) mode M8 is that the pressure of the supply circuit 12 is higher than the threshold value and the water content of the gas tank 30 is high. Alternatively, the ECU 80 may shift to the forced regeneration (eighth action) mode M8 when at least the water content of the gas tank 30 is high. That is, in step S43, the ECU 80 determines whether the water content of the gas tank 30 is high as a condition for shifting to the forced regeneration (eighth action) mode M8.

[0157] In the above embodiment, the filter 17 includes the oil-capturing portion, but the oil-capturing portion may be omitted from the filter 17 .

[0158] In the above embodiment, the air drying circuit is not limited to the above structure. In short, the air drying circuit can be configured to execute the supply (first action) mode M1, the purge (second action) mode M2, the regeneration (third action) mode M3, the non-purge supply stop (fifth action) mode M5, the compressor assist (sixth action) mode M6, and the regeneration supply (seventh action) mode M7. Therefore, the air drying circuit does not set the degreasing (fourth action) mode M4, the forced regeneration (eighth action) mode M8, the engine start assist (ninth action) mode M9, and the decompression (tenth action) mode M10 as necessary actions.

[0159] In the above-mentioned embodiment, the purge (second operation) mode M2 ​​may be omitted.

[0160] Furthermore, the regenerative supply (seventh operation) mode M7 may be omitted.

[0161] In addition, the non-purge supply stop (fifth operation) mode M5 may be omitted.

[0162] In the above embodiment, the air supply system 10 is described as being mounted on a vehicle such as a truck, a bus, or a construction machine. In other embodiments, the air supply system 10 may be mounted on another mobile body such as a car or a railway vehicle.

[0163] ECU 80 is not limited to software processing of all the processes executed by itself. For example, ECU 80 may also have a dedicated hardware circuit (such as an application-specific integrated circuit: ASIC), which performs hardware processing on at least a part of the processes executed by ECU 80 itself. That is, ECU 80 can be constructed to include the following circuits: 1) one or more processors that act according to a computer program (software), 2) one or more dedicated hardware circuits that execute at least a part of various processes, or 3) a combination thereof. The processor includes a CPU and a memory such as RAM and ROM, and the memory stores program codes or instructions configured to enable the CPU to execute processes. The memory, i.e., computer-readable media, includes all available media that can be accessed by general-purpose or special-purpose computers.

[0164] Description of Reference Numerals

[0165] 4: compressor; 10: air supply system; 11: air drying circuit; 12: supply circuit; 15: upstream check valve; 16: branch passage; 17: filter; 18: air supply passage; 19: downstream check valve; 20: bypass flow path; 21: regeneration control valve; 22: throttle hole; 25: drain valve; 26A: regulator; 26B: unloading control valve; 27: drain outlet as a drain outlet; 30: gas tank; 50: pressure sensor; 51: humidity sensor; 52: temperature sensor; 53: pressure sensor; 80: ECU; 80A: storage unit; E61~E67: wiring.

Claims

1. An air supply system comprising: an air drying circuit provided between a compressor that delivers compressed air by power transmitted from a driving source and an air tank that stores compressed dry air, the air drying circuit having a filter including a desiccant that captures moisture; and a control device, which controls the air drying circuit, in, The control device is composed of: performing a supply operation, wherein the supply operation is an operation of causing the compressed air sent from the compressor to pass through the filter to store the compressed dry air in the air tank, performing a regeneration operation, wherein the regeneration operation is an operation of passing the compressed dry air stored in the air tank through the filter in a reverse direction to discharge the fluid that has passed through the filter from a discharge port, After performing the regeneration action, a filling action is performed when the compressor is in a non-operating state where no air is compressed. The filling action is an action of allowing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to fill the compressed dry air into the air drying circuit, thereby reducing the load on the compressor at the start of operation.

2. The air supply system according to claim 1, characterized in that: The control device is composed of: After performing the regeneration action, performing the filling action when the driving source is stopped, The compressor is stopped by sending an air pressure signal to the compressor when the driving source is restarted.

3. The air supply system according to claim 1 or 2, characterized in that: The control device is composed of: performing a purge action, wherein the purge action is an action of passing the compressed dry air of the air drying circuit through the filter in the reverse direction to discharge the fluid that has passed through the filter from the discharge port, The filling action is performed after the purging action is performed.

4. The air supply system according to claim 3, characterized in that: The control device is composed of: After performing the purging action, performing the filling action when the driving source is stopped, The compressor is stopped by sending an air pressure signal to the compressor when the driving source is restarted.

5. The air supply system according to claim 1 or 2, characterized in that: The control device is configured to execute a non-purge supply stop operation of stopping the compressor by sending an air pressure signal to the compressor while stopping discharge of the fluid from the discharge port after executing the filling operation.

6. The air supply system according to claim 5, characterized in that The control device is configured to execute a regenerative supply operation after executing the non-purge supply stop operation. The regenerative supply operation is an operation of driving the compressor to send the compressed air to the filter and supply the compressed air to the air tank when the drive source is in a no-load state.

7. The air supply system according to claim 6, characterized in that The control device is configured to execute the non-purge supply stop operation when the regeneration supply operation is performed for a predetermined time.

8. The air supply system according to claim 1 or 2, characterized in that: Also available: a discharge valve connecting a branch path connected to the air drying circuit to the discharge port; a regeneration control valve that switches between a forward flow from the filter toward the gas tank and a reverse flow from the gas tank toward the filter; as well as a compressor control valve that sends an air pressure signal for stopping the compressor, The control device is configured to control the discharge valve, the regeneration control valve, and the compressor control valve.

9. A control method for an air supply system, the air supply system comprising: an air drying circuit provided between a compressor that delivers compressed air by power transmitted from a driving source and an air tank that stores compressed dry air, the air drying circuit having a filter including a desiccant that captures moisture; and a control device that controls the air drying circuit, In the control method of the air supply system, The control device is configured to perform the following processing: performing a supply operation, wherein the supply operation is an operation of causing the compressed air sent from the compressor to pass through the filter to store the compressed dry air in the air tank, performing a regeneration operation, wherein the regeneration operation is an operation of passing the compressed dry air stored in the air tank through the filter in a reverse direction to discharge the fluid that has passed through the filter from a discharge port, After performing the regeneration action, a filling action is performed when the compressor is in a non-operating state where no air is compressed. The filling action is an action of allowing the compressed dry air stored in the air tank to pass through the filter in a reverse direction to fill the compressed dry air into the air drying circuit, thereby reducing the load on the compressor at the start of operation.

10. A computer program product, comprising a control program for an air supply system, the air supply system comprising: an air drying circuit provided between a compressor that delivers compressed air by power transmitted from a driving source and an air tank that stores compressed dry air, the air drying circuit having a filter including a desiccant that captures moisture; and a control device that controls the air drying circuit, The control program of the air supply system causes the control device to function as the following parts: a supply operation execution unit that executes a supply operation, wherein the supply operation is an operation of causing the compressed air sent from the compressor to pass through the filter to store the compressed dry air in the air tank, a regeneration operation execution unit that executes a regeneration operation, wherein the regeneration operation causes the compressed dry air stored in the air tank to pass through the filter in a reverse direction to discharge the fluid that has passed through the filter from a discharge port, and A filling action execution unit performs a filling action after executing the regeneration action and when the compressor is in a non-operating state where no air is compressed. The filling action is an action of filling the compressed dry air stored in the air tank into the air drying circuit by passing the compressed dry air through the filter in a reverse direction, thereby reducing the load of the compressor at the start of operation.

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