Operation control method for an engine-driven compressor and engine-driven compressor

Abstract

To minimize the starting load of engine-driven compressors. [Solution] An auxiliary shut-off valve 30 is provided to open and close the intake passage 115 that communicates with the intake port 41 of the compressor body 40. The engine of the engine-driven compressor 1 is started with the control of the intake control valve 11 by the pressure regulating valve 13 disabled and the auxiliary shut-off valve 30 closed. As a result, even if the engine is started with the intake control valve 11 open, the intake passage 115 of the compressor body 40 is closed by the auxiliary shut-off valve 30, thereby limiting the intake of the compressor body 40, and making it possible to start the engine with the load reduced as much as possible.

Description

Technical Field

[0001] The present invention relates to an operation control method for an engine-driven compressor, and an engine-driven compressor that executes the operation control method, and more specifically, relates to an operation control method for an engine-driven compressor that enables starting under a reduced load condition and an engine-driven compressor that executes the operation control method. Background Art

[0002] An engine-driven compressor that includes an engine such as a diesel engine as a drive source for driving a compressor body is widely used for outdoor work such as civil engineering work sites and construction sites where it is difficult to secure a power supply.

[0003] As such an engine-driven compressor, Patent Document 1 described below discloses an engine-driven compressor 300 including an oil-cooled compressor body 340 that compresses a gas to be compressed together with lubricating oil and discharges the mixture as a gas-liquid mixed fluid as shown in Fig. 8.

[0004] In addition to the aforementioned compressor body 340 and an engine (not shown), the engine-driven compressor 300 is provided with a receiver tank 360 for separating lubricating oil discharged together with compressed gas from the compressor body 340, and is configured such that the compressed gas obtained after separating the lubricating oil in the receiver tank 360 can be supplied to a consumption side connected with an unillustrated pneumatic working machine or the like.

[0005] The lubricating oil recovered in the receiver tank 360 is configured to be supplyable to the compressor body 340 through an oil supply passage 361 provided with an oil cooler 362 and an oil filter (not shown) by using the pressure in the receiver tank 360.

[0006] Such an engine-driven compressor 300 is provided with an intake adjustment device 310 that adjusts the intake amount of the compressor body 340 according to the pressure in the receiver tank 360, so that compressed gas with stable pressure can be supplied to the consumption side.

[0007] As the intake control device 310, the engine-driven compressor 300 shown in Figure 8 is provided with a normally open intake control valve 311 that opens and closes the intake port 341 of the compressor body 340, and a control passage 312 that communicates with the valve closing pressure receiving chamber of the intake control valve 311. This control passage 312 is also connected to the receiver tank 360 via the block manifold 326 and the common passage 327.

[0008] Furthermore, the control channel 312 is provided with a pressure regulating valve 313 that opens when the pressure inside the receiver tank 360 is equal to or greater than a predetermined rated pressure.

[0009] By providing the intake control device 310 configured in this way, when the pressure in the receiver tank 360 exceeds the rated pressure, the pressure control valve 313 starts opening and begins introducing compressed gas from the receiver tank 360 into the pressure-receiving chamber of the intake control valve 311. The intake control valve 311 then restricts or closes the intake port 341 of the compressor body 340, thereby reducing or stopping the amount of compressed gas produced.

[0010] On the other hand, when the pressure in the receiver tank 360 drops below the rated pressure, the pressure regulating valve 313 closes, stopping the introduction of compressed gas into the pressure-receiving chamber of the intake regulating valve 311. This causes the intake regulating valve 311 to open, opening the intake port 341 of the compressor body 340, and the generation of compressed gas by the compressor body 340 begins.

[0011] Therefore, by repeatedly performing this intake control, the pressure inside the receiver tank 360 can be brought close to the aforementioned rated pressure.

[0012] In the engine-driven compressor 300 configured as described above, the engine, which is the driving source for the compressor body 340, has low torque at low rotational speeds and is prone to stalling when a load is applied during startup.

[0013] In particular, in engine-driven compressors equipped with smaller engines that have increased maximum output by adopting a common rail system or adding a turbocharger, due to the demand for engine downsizing to comply with exhaust gas regulations, there are advantages to electronic control, but the starting torque of the engine is lower compared to conventional engines that produce a similar maximum output, making stalling during startup more likely.

[0014] On the other hand, the pressure in the receiver tank 360 of the engine-driven compressor 300 during startup is reduced to below the rated pressure (for example, atmospheric pressure) due to purging performed during shutdown. Therefore, when starting the engine-driven compressor 300 equipped with the aforementioned intake control device 310, the intake control valve 311 is opened when the engine is started, resulting in a higher load on the engine than during startup.

[0015] To address the problem of high load during engine startup, the engine-driven compressor described in Patent Document 1 is provided with a starting load reduction device 320 to reduce the load during startup.

[0016] The engine-driven compressor 300 shown in Figure 8 includes a starting load reduction device 320 that bypasses the pressure regulating valve 313 and connects the valve closing pressure receiving chamber of the intake regulating valve 311 to the receiver tank 360 (between the block manifolds 326 in the illustrated configuration), and bypass valves 323 and 324 that open and close this bypass passage 320.

[0017] By providing such a starting load reduction device 320, in the engine-driven compressor 300 shown in Figure 8, the pressure regulating valve 313 is bypassed by opening the bypass valves 323 and 324, and the closed pressure receiving chamber of the intake regulating valve 311 and the receiver tank 360 are connected via the bypass passage 320 (321, 322), and the engine is started in this state.

[0018] As a result, when the discharge of compressed gas begins due to the rotation of the screw rotor of the compressor body 340, the intake control valve 311 closes and the system switches to no-load operation, thereby reducing the load on the engine immediately after starting up.

[0019] Furthermore, if the engine is started with the intake control valve 311 fully closed to reduce the starting load, and then the intake control valve 311 is kept closed during the warm-up period, the pressure inside the receiver tank 360 is higher than the atmospheric pressure, but this pressure is relatively low, for example, around 0.1 MPa in gauge pressure.

[0020] On the other hand, since the compressor body 340 is supplied with lubricating oil recovered in the receiver tank 360 using the pressure in the receiver tank 360, insufficient oil supply to the compressor body 340 may occur during warm-up operation when the pressure in the receiver tank 360 is low, or immediately after transitioning from warm-up operation to normal operation.

[0021] Therefore, in order to ensure an appropriate amount of oil is supplied to the compressor body 340 during warm-up operation and immediately after transitioning from warm-up operation to normal operation, the engine-driven compressor 300 described in Patent Document 1 shown in Figure 8 is provided with a plurality of bypass passages 321 and 322 and bypass valves 323 and 234 that open and close each bypass passage 321 and 322 as the aforementioned starting load reduction device 320.

[0022] When the engine is started, all (two in the illustrated example) bypass valves 323 and 324 are opened at the same time, so that the intake adjustment valve 311 is fully closed as the engine is started. After the engine is started, when the operating state of the engine becomes stable due to satisfaction of a predetermined condition (for example, elapse of a predetermined operating time), one of the bypass valves 323 and 324 is closed to reduce the amount of compressed gas introduced into the valve closing pressure receiving chamber of the intake adjustment valve 311, thereby opening the intake adjustment valve 311 at an opening less than full open. This increases the pressure in the receiver tank 60 to an oil supply start pressure, which is a predetermined lower pressure relative to the rated pressure but a pressure that can ensure the amount of oil supplied to the compressor body 340, and then shifts to normal operation, thereby solving the problem of insufficient oil supply during warm-up operation and immediately after shifting to normal operation. [PRIOR ART DOCUMENTS] [PATENT DOCUMENTS]

[0023] [Patent Document 1] Japanese Unexamined Patent Publication No. 2022-185735 [Patent Document 2] Japanese Unexamined Patent Publication No. 2014-20267 [Summary of the Invention] [Problem to be Solved by the Invention]

[0024] The engine-driven compressor 300 described in the aforementioned Patent Document 1 is excellent in that it can simultaneously satisfy the conflicting requirements of starting the engine in a load-reduced state and securing the amount of oil supplied to the compressor body 340 during warm-up operation and immediately after shifting from warm-up operation to normal operation.

[0025] However, when the starting load reducing device 320 having the above-described configuration is provided in an engine-driven compressor 300 that performs the valve closing operation of the intake adjustment valve 311 using the pressure in the receiver tank 360 as the operating pressure, the engine is started with the intake adjustment valve 311 in an open state, and the intake adjustment valve 311 closes after a delay from the start of the engine starting operation.

[0026] That is, the intake regulating valve 311 closes only when the screw rotor of the compressor body 340 is rotated by the starting of the engine, the compressor body 340 starts discharging compressed gas into the receiver tank 360, and the pressure in the receiver tank 360 rises to be equal to or higher than the operating pressure of the intake regulating valve 311.

[0027] As a result, even in the engine-driven compressor 300 provided with the starting load reducing device 320 described in Patent Document 1, during a starting operation (for example, rotation of the engine by a starter motor and ignition to fuel) or immediately thereafter, the intake regulating valve 311 has not been closed yet, and a large load is still applied to the engine.

[0028] Therefore, if the load applied to the engine during such starting can also be reduced, the starting of the engine of the engine-driven compressor 300 can be performed more smoothly.

[0029] Further, in the present invention, the auxiliary opening / closing valve starts to open before shifting to normal operation, whereas in Patent Document 2, the auxiliary opening / closing valve maintains the "closed" state until shifting to normal operation. The means of Document 2 causes a situation where a sufficient amount of oil supply to the compressor body 340 cannot be ensured during warm-up operation or immediately after shifting from warm-up operation to normal operation.

[0030] The present invention relates to further improvements to the engine-driven compressors of the aforementioned Patent Documents 1 and 2, and an object of the present invention is to provide an operation control method for an engine-driven compressor, and an engine-driven compressor that executes this operation control method, which makes it possible to further reduce the load applied to the engine at starting, while maintaining the functions of the engine-driven compressor introduced as the aforementioned Patent Document 1 that achieves both reduction of starting load and securing of oil supply pressure. [Means for Solving the Problem]

[0031] The means for solving the problem are described below, along with the reference numerals used in the embodiments for carrying out the invention. These reference numerals are included to clarify the correspondence between the claims and the descriptions of the embodiments for carrying out the invention, and needless to say, they are not used restrictively to interpret the technical scope of the present invention.

[0032] To achieve the above objective, the starting control method for the engine-driven compressor 1 of the present invention is as follows: In an operation control method for an engine-driven compressor 1, the compressor 1 comprises an engine (not shown), an oil-cooled compressor body 40 driven by the engine, a receiver tank 60 that introduces a gas-liquid mixed fluid of compressed gas and lubricating oil discharged from the compressor body 40, separates it into compressed gas and lubricating oil, and supplies the separated lubricating oil to the compressor body 40 using its internal pressure, an intake control valve 11 that controls the intake of air to the compressor body 40, a control passage 12 that connects the valve-closing pressure-receiving chamber 113 of the intake control valve 11 and the receiver tank 60, and a pressure regulating valve 13 that opens and closes the control passage 12 according to the pressure in the receiver tank 60, and during normal operation, the pressure regulating valve 13 controls the opening and closing operation of the intake control valve 11 to control the intake of the compressor body 40 by opening the control passage 12 when the pressure in the receiver tank 60 is above a predetermined rated pressure and closing the control passage 12 when it is below the rated pressure, An auxiliary on / off valve 30 is provided to open and close the suction passage 115 that communicates with the intake port 41 of the compressor body 40, With the control of the intake control valve 11 by the pressure regulating valve 13 disabled and the auxiliary on-off valve 30 closed, the engine is started and a starting load reduction operation is performed in which the pressure in the receiver tank 60 is maintained at a pressure less than the predetermined starting load reduction pressure P1, which is less than the rated pressure. When the termination conditions for the starting load reduction operation are met, the intake control valve 11 is opened to less than fully open, and the auxiliary on-off valve 30 is opened to raise the pressure in the receiver tank 60 to a predetermined oil supply pressure P2 that is less than the rated pressure but higher than the starting load reduction pressure P1 and necessary to ensure oil supply to the compressor body 40, and an oil supply supply operation is performed to maintain the oil supply pressure P2. When the termination conditions for the fuel supply amount securing operation are met, the deactivation is released, the opening and closing control of the intake control valve 11 is started by the pressure regulating valve 13, and the auxiliary opening and closing valve 30 is fully opened, and the system transitions to the normal operation (Claim 1).

[0033] In the aforementioned control method for operating the engine-driven compressor 1, A bypass flow path 20 is provided, which allows communication between the receiver tank 60 and the valve closing pressure receiving chamber 113 of the intake control valve 11 by bypassing the pressure regulating valve 13, and whose flow path area can be changed. By connecting the receiver tank 60 and the valve-closing pressure-receiving chamber 113 of the intake control valve 11 with the bypass flow path 20 which has the maximum flow area, and starting the engine, the starting load reduction operation is performed with the intake control valve 11 closed as the engine starts. By narrowing the flow area of ​​the bypass flow path 20 and opening the intake control valve 11 to less than fully open, the starting load reduction operation is terminated and the oil supply amount securing operation is started, By blocking communication between the receiver tank 60 and the valve-closing pressure-receiving chamber 113 of the intake control valve 11 through the bypass passage 20, the fuel supply amount securing operation can be terminated and the system can be switched to normal operation (Claim 2).

[0034] The auxiliary on-off valve 30 may be configured to be fully closed when the pressure in the receiver tank 60 is less than the starting load reduction pressure P1, to start opening when the pressure becomes equal to or greater than the starting load reduction pressure P1, and to be fully open when it exceeds the oil supply amount securing pressure P2 (Claim 3).

[0035] In this case, when the auxiliary on-off valve 30 is closed, a small communication passage 39 is provided that connects the primary side and the secondary side of the auxiliary on-off valve 30, The auxiliary on-off valve 30 may be opened and closed using the pressure inside the receiver tank 60 as the operating pressure (Claim 4).

[0036] Alternatively, instead of the above configuration, the opening and closing of the auxiliary on-off valve 30 may be performed by an electric motor 32' (Claim 5).

[0037] At least a portion of the bypass channel 20 may be formed by a collection of multiple parallel branch channels 21, 22, and each branch channel 21, 22 may be made open and closed by providing electromagnetic valves 23, 24 in each branch channel 21, 22, and the flow area of ​​the bypass channel 20 may be changed by changing the number of branch channels 21, 22 that are opened or closed (Claim 6).

[0038] Alternatively, instead of the above configuration, the flow area of ​​the bypass flow path 20 may be changed by operating a flow control valve 25, such as an electric valve, provided in the bypass flow path 20 (Claim 7).

[0039] Furthermore, the engine-driven compressor 1 of the present invention is In an engine-driven compressor 1, the compressor 1 comprises an engine (not shown), an oil-cooled compressor body 40 driven by the engine, a receiver tank 60 that introduces a gas-liquid mixed fluid of compressed gas and lubricating oil discharged by the compressor body 40, separates it into compressed gas and lubricating oil, and supplies the separated lubricating oil to the compressor body 40 using its internal pressure, an intake control valve 11 that controls the intake of air to the compressor body 40, a control passage 12 that connects the valve-closing pressure-receiving chamber 113 of the intake control valve 11 and the receiver tank 60, and a pressure regulating valve 13 that opens and closes the control passage 12 according to the pressure in the receiver tank 60, and during normal operation, the pressure regulating valve 13 controls the opening and closing operation of the intake control valve 11 to control the intake of the compressor body 40 by opening the control passage 12 when the pressure in the receiver tank 60 is above a predetermined rated pressure and closing the control passage 12 when it is below the rated pressure, A starting control device 20 controls the opening and closing of the intake control valve 11 by disabling the opening and closing control of the intake control valve 11 by the pressure regulating valve 13, An auxiliary on / off valve 30 opens and closes an intake passage 115 that communicates with the intake port 41 of the compressor body 40, The engine-driven compressor 1 is equipped with a controller 50 that controls the operation of each part of the engine-driven compressor 1. The auxiliary on-off valve 30 is configured to close when the pressure in the receiver tank 60 is below a predetermined starting load reduction pressure P1, which is a pressure below the rated pressure, to open when it is above the starting load reduction pressure P1, and to fully open when it is below the rated pressure, above the starting load reduction pressure P1, and exceeds a predetermined oil supply amount securing pressure P2, which is the pressure necessary to supply oil to the compressor body 40. The controller 50, The engine is started with the start control device 20 in which the control of the intake control valve 11 by the pressure control valve 13 is disabled, and the engine is operated in a start load reduction operation in which the pressure in the receiver tank 60 is maintained at a pressure less than the predetermined start load reduction pressure P1, which is less than the rated pressure. When the termination conditions for the starting load reduction operation are met, the starting control device 20 is operated to open the intake control valve 11 to less than fully open, raising the pressure in the receiver tank 60 to the oil supply amount securing pressure P2, and an oil supply amount securing operation is performed to maintain that pressure. When the termination conditions for the fuel supply amount securing operation are met, the deactivation by the start control device 20 is released, and the control of the intake control valve 11 by the pressure regulating valve 13 is started to raise the pressure in the receiver tank 60 to the fuel supply amount securing pressure P2 or higher, thereby transitioning to the normal operation (Claim 8).

[0040] As the starting control device 20, a bypass flow path 20 is provided that allows the pressure regulating valve 13 to be bypassed and enables communication between the receiver tank 60 and the valve closing pressure receiving chamber 113 of the intake regulating valve 11, and the flow path area can be changed. The controller 50, By connecting the receiver tank 60 and the valve-closing pressure-receiving chamber 113 of the intake control valve 11 with the bypass flow path 20 which has the maximum flow area, and starting the engine, the starting load reduction operation is performed with the intake control valve 11 closed as the engine starts. By narrowing the flow area of ​​the bypass flow path 20, the intake control valve 11 is opened to an opening degree less than fully open, thereby transitioning from the starting load reduction operation to the oil supply amount securing operation, The system may be configured to transition from the fuel supply amount securing operation to the normal operation by blocking communication between the receiver tank 60 and the valve closing pressure receiving chamber 113 of the intake control valve 11 through the bypass passage 20 (Claim 9).

[0041] The auxiliary on-off valve 30 is configured as a normally closed on-off valve that opens using the pressure inside the receiver tank 60 as the operating pressure, A small communication passage 39 is provided that connects the primary and secondary sides of the auxiliary on-off valve 30 when the auxiliary on-off valve 30 is closed (Claim 10).

[0042] Alternatively, the auxiliary on-off valve 30 may be provided with an electric motor 32' (see Figure 6) that performs the opening and closing operation of the valve body 31 of the auxiliary on-off valve 30. The controller 50, The operation of the electric motor 32' may be controlled to control the opening and closing of the auxiliary on-off valve 30 (Claim 11).

[0043] At least a portion of the bypass channel 20 is formed by a collection of multiple branch channels (first branch channel 21, second branch channel 22 in this embodiment) arranged in parallel, and electromagnetic valves (first solenoid valve 23, second solenoid valve 24) are provided to open and close each of the branch channels 21, 22. The controller 50, The flow area of ​​the bypass flow path 20 may be changed by changing the number of electromagnetic on-off valves 23 and 24 that are opened or closed (Claim 12).

[0044] Alternatively, an electrically operated flow control valve 25 may be provided in the bypass flow path 20. The controller 50, The flow area of ​​the bypass flow path 20 may be changed by changing the opening degree of the flow control valve 25 (Claim 13). [Effects of the Invention]

[0045] With the configuration of the present invention described above, the engine-driven compressor 1 that implements the operation control method of the present invention retains the functions of the engine-driven compressor 300 introduced in the aforementioned Patent Document 1, which are to reduce the starting load and ensure the oil supply pressure, while also enabling a further reduction in the load on the engine during startup.

[0046] In other words, in an engine-driven compressor 1,300 that uses the pressure in the receiver tanks 60,360 as the operating pressure to close the intake control valves 11,311, even if the engine is started with the pressure control valves 13,313 bypassed and the receiver tanks 60,360 and the pressure-receiving chambers of the intake control valves 11,311 directly connected, the engine starting operation itself is performed with the intake control valves 11,311 fully open, and then the intake control valves 11,311 close.

[0047] However, in the engine-driven compressor 1 of the present invention, an auxiliary on-off valve 30 is provided in addition to the intake control valve 11. By starting the engine with this auxiliary on-off valve 30 closed, even when the intake control valve 11 is fully open when the engine is started, the intake to the compressor body 40 is controlled, and therefore the load on the engine is reduced as much as possible when the engine is started, making it possible to further reduce the load at engine startup.

[0048] This further reduction in starting load made it possible to suppress vibrations that occur during starting, thereby reducing the load on connecting members such as rubber couplings that connect the engine and the compressor body 40, and extending their lifespan.

[0049] The configuration of the aforementioned starting control device 20, which controls the opening and closing operation of the intake control valve 11 by disabling the control of the intake control valve 11 by the pressure regulating valve 13, is not particularly limited. However, in a configuration in which the aforementioned starting control device is a bypass flow path 20 that bypasses the pressure regulating valve 13 and enables communication between the receiver tank 60 and the valve closing pressure receiving chamber 113 of the intake control valve 11, it is possible to disable the control of the intake control valve 11 by the pressure regulating valve 13 and control the opening and closing of the intake control valve 11 during startup with a relatively simple configuration.

[0050] The auxiliary on-off valve 30 is configured to close when the pressure in the receiver tank 60 is below a predetermined starting load reduction pressure P1, which is below the rated pressure, to open when it is above the starting load reduction pressure P1, and to fully open when it is below the rated pressure, above the starting load reduction pressure P1, and exceeds a predetermined oil supply amount securing pressure P2, which is the pressure necessary to supply oil to the compressor body 40. In this configuration, the auxiliary on-off valve 30 can be made to perform the necessary opening and closing operations in response to the opening and closing of the starting control device (bypass flow path) 20 and the pressure changes in the receiver tank 60 due to changes in the flow path area.

[0051] In the configuration where the auxiliary shut-off valve 30 is a normally closed shut-off valve that opens using the pressure inside the receiver tank 60 as the operating pressure, it is not necessary to control the operation of the auxiliary shut-off valve 30 by the controller 50, and the configuration of the controller 50 can be simplified.

[0052] On the other hand, in a configuration in which the auxiliary shut-off valve 30 is equipped with an electric motor 32' that causes the valve body 31 of the auxiliary shut-off valve 30 to open and close, the controller 50 can control the opening and closing operation of the auxiliary shut-off valve 30 by controlling the electric motor 32', and the structure of the auxiliary shut-off valve 30 can be simplified.

[0053] Furthermore, in a configuration in which the opening and closing of the auxiliary shut-off valve 30 is controlled by an electric motor 32', it is no longer necessary to increase the pressure in the receiver tank 60 to obtain the operating pressure of the auxiliary shut-off valve 30. This eliminates the need to provide a minute connecting passage 39 that connects the primary and secondary sides of the auxiliary shut-off valve 30 when the auxiliary shut-off valve 30 is closed. As a result, the load generated by the compression of the gas to be compressed that was drawn into the compressor body 40 via this minute connecting passage 39 can also be reduced, thereby achieving an even greater reduction in the starting load.

[0054] Furthermore, since the intake volume of the compressor body 40 can be adjusted by adjusting the opening degree of the auxiliary on-off valve 30, it is possible to omit the flow rate adjustment configuration (for example, the second branch passage 22 and the second solenoid valve 24) that is provided on the bypass passage 20 side in order to adjust the opening degree of the intake control valve 11.

[0055] In a configuration in which at least a portion of the bypass flow path 20 is formed by a collection of multiple parallel branch flow paths (first branch flow path 21, second branch flow path 22), and electromagnetic valves (first solenoid valve 23, second solenoid valve 24) are provided to open and close each branch flow path 21, 22, the flow area of ​​the bypass flow path 20 could be easily changed by changing the number of electromagnetic valves 23, 24 that are opened or closed.

[0056] On the other hand, in a configuration in which an electrically operated flow control valve 25 is provided in the bypass flow path, and the flow path area of ​​the bypass flow path 20 is changed by changing the opening degree of this flow control valve 25, the flow path area can be changed steplessly, and the opening degree of the intake control valve 11 can be adjusted more precisely. [Brief explanation of the drawing]

[0057] [Figure 1] An explanatory diagram of the overall configuration of the engine-driven compressor of the present invention. [Figure 2] This is a cross-sectional view of the main part of an intake control valve equipped with an auxiliary on / off valve. (A) shows an intake control valve that does not have a check valve function, and (B) shows an intake control valve that does have a check valve function. [Figure 3] A diagram illustrating the functions of the controller. [Figure 4] A time chart showing the operation of each part of the engine-driven compressor of the present invention, and the changes in the pressure inside the receiver tank. [Figure 5] A graph showing the pressure change in the receiver tank during startup of the engine-driven compressor of the present invention and a conventional engine-driven compressor (Patent Document 1). [Figure 6] An explanatory diagram of the overall configuration showing a modified example of the engine-driven compressor of the present invention. [Figure 7] An explanatory diagram of the overall configuration showing another modified example of the engine-driven compressor of the present invention. [Figure 8] An explanatory diagram of the overall configuration of a conventional engine-driven compressor (Patent Document 1). [Modes for carrying out the invention]

[0058] Next, embodiments of the present invention will be described with reference to the attached drawings.

[0059] [Overall configuration of an engine-driven compressor] Reference numeral 1 in Figure 1 denotes the engine-driven compressor of the present invention. This engine-driven compressor 1 comprises a compressor body 40 which is an oil-cooled screw compressor that compresses a gas to be compressed together with lubricating oil, an engine (not shown) that drives the compressor body 40, and a receiver tank 60 that stores the compressed gas discharged from the compressor body 40. The compressed gas discharged from the compressor body 40 together with the lubricating oil is separated from the lubricating oil in the receiver tank 60, and the compressed gas from which the lubricating oil has been removed can be supplied to an air-powered work machine or the like (not shown) connected to the consumption side.

[0060] The lubricating oil recovered in the receiver tank 60 is pushed out by the pressure inside the receiver tank 60 and can be supplied back to the compressor body 40 via an oil supply passage 61 equipped with an oil cooler 62 and an oil filter 63.

[0061] [Intake adjustment device] The engine-driven compressor 1 configured as described above is equipped with an intake adjustment device 10 that adjusts the intake so that the pressure in the receiver tank 60 approaches a predetermined rated pressure. When the pressure in the receiver tank 60 exceeds a predetermined rated pressure, the intake port 41 of the compressor body 40 is throttled or closed, and when it falls below the rated pressure, it is fully opened. In this respect, it is similar to the configuration of the conventional engine-driven compressor 300 described with reference to Figure 8.

[0062] Furthermore, this intake control device 10 is similar in configuration to the conventional engine-driven compressor 300 described with reference to Figure 8, in that it is composed of an intake control valve 11 that controls the opening and closing of the intake port 41 of the compressor body 40, a control passage 12 that connects the valve-closing pressure-receiving chamber 113 of the intake control valve 11 and the receiver tank 60, and a pressure control valve 13 that opens the control passage 12 when the pressure in the receiver tank 60 is above a predetermined rated pressure and closes the control passage 12 when it is below the rated pressure.

[0063] [Intake control valve] The intake control valve 11, which is a main component of the intake control device 10, opens and closes the intake port 41 of the compressor body 40, and in this embodiment, the intake control valve 11 shown in Figure 2 is used as an example.

[0064] The intake control valve 11 shown in Figure 2 is configured such that an intake passage 115 is formed within the body (valve casing) 111 through which the compressed gas passes, and the intake passage 115 can be closed by seating the valve body 116 on the valve seat 115a provided within the intake passage 115.

[0065] This valve body 116 is a so-called "umbrella-type valve" in which a valve stem 116a is attached to a disc-shaped valve body 116. With the valve stem 116a inserted into a cylindrical sleeve 117 formed inside the body 111, the valve body 116 is moved back and forth in the axial direction of the sleeve 117, allowing it to move between a closed valve position where the valve body 116 is seated on the valve seat 115a and an open valve position where the valve body 116 is separated from the valve seat 115a.

[0066] To enable the movement of the valve body 116, a cylinder 112 is formed coaxially with the sleeve 117 in the valve body 111 of the intake control valve 11, and communicates with the intake passage 115 via the aforementioned sleeve 117.

[0067] This cylinder 112 forms an airtight chamber when the valve stem 116a is inserted into the sleeve 117 and the end opposite to the forming side of the sleeve 117 is sealed with an end plate 118. This airtight chamber (cylinder) 112 is divided into two chambers via a pressure receiving body 119, which in this embodiment is a piston, connected to the other end of the valve stem 116a. A valve closing pressure receiving chamber 113 of the intake control valve 11 is formed on the end plate 118 side, and an auxiliary pressure receiving chamber 114 is formed on the opposite side of the valve closing pressure receiving chamber 113 via the piston 119.

[0068] In the illustrated configuration, in order to make the intake control valve 11 a normally open (NO) type, a spring 114a that pushes the piston 119 toward the valve closing pressure chamber 113 is housed in the aforementioned auxiliary pressure chamber 114, thereby giving the auxiliary pressure chamber 114 the function of a spring chamber. However, if the intake control valve 11 can be made a normally open type, the spring 114a does not necessarily need to be provided in the auxiliary pressure chamber 114.

[0069] In addition, instead of the intake control valve 11 with the configuration shown in Figure 2(A), an intake control valve 11 with a backflow prevention function, as shown in Figure 2(B), may be used.

[0070] In this configuration, the valve stem 116a is divided into a valve stem 116a' located on the valve body 116 side and a valve stem 119a located on the pressure-receiving body (piston) 119 side. A spring 116b is provided between the valve stem 116a' on the valve body 116 side and the valve stem 119a on the pressure-receiving body (piston) 119 side to bias the valve body 116 toward the valve seat 115a.

[0071] The biasing force of the spring 116b ensures that the valve body 116 contacts the valve seat 115a even when the pressure-receiving body (piston) 119 is in the open position on the left side of the paper.

[0072] The biasing force of this spring 116b is weak, and when the pressure-receiving body (piston) 119 is in the open valve position on the left side of the paper, if the pressure in the intake passage 115, which is secondary to the valve seat 115a, becomes negative, the valve body 116 moves away from the valve seat 115a, and the compressor body 40 is configured to be able to draw in the gas to be compressed.

[0073] On the other hand, even when the pressure-receiving body (piston) 119 is in the open valve position on the left side of the paper, if the pressure in the secondary suction passage 115 rises relative to the valve seat 115a, the valve body 116 is pressed against the valve seat 115a, thereby preventing backflow.

[0074] Thus, when an intake control valve 11 with a backflow prevention function is used in the engine-driven compressor 1 of the present invention, even when the valve body 116 is in contact with the valve seat 115a, the state in which the valve body 116 separates from the valve seat 115a and the compressor body 40 can take in air when the pressure in the intake passage on the secondary side of the valve seat 115a becomes lower than the pressure in the intake passage on the primary side of the valve seat 115a is included in the "open" or "open valve" state of the intake control valve 11.

[0075] Furthermore, in the configuration of the intake control valve 11 described with reference to Figures 2(A) and 2(B), not only the valve body 116 and valve seat 115a, but also the cylinder 112 and piston 119 for moving the valve body 116 forward and backward are all provided within a common body (valve casing) 111. However, it is also possible to adopt a configuration in which the intake control valve body, which does not have a valve body drive mechanism, and the drive mechanism such as an unloader regulator that drives the valve body of this intake control valve body are separate components. In this case, the aforementioned valve closing pressure receiving chamber 113, auxiliary pressure receiving chamber 114, and pressure receiving body 119 are formed within the unloader regulator.

[0076] Furthermore, in the intake control valve 11 described with reference to Figures 2(A) and 2(B), a configuration is adopted in which the airtight chamber cylinder 112 is partitioned as a drive mechanism for the valve body 116 by providing a piston 119 as a pressure receiving body that moves in response to the pressure of compressed gas introduced into the valve closing pressure receiving chamber 113. However, the pressure receiving body 119 is not limited to the aforementioned piston, and any pressure receiving body 119 that can control the operation of the valve body 116 with the compressed gas introduced into the valve closing pressure receiving chamber 113 may be used as the pressure receiving body 119, for example, a diaphragm.

[0077] [Starting control device (bypass channel)] The engine-driven compressor 1 of the present invention is provided with a starting control device 20 that controls the operation of the intake control valve 11 during startup by disabling the opening and closing control of the intake control valve 11 by the pressure regulating valve 13 provided in the control passage 12 described above.

[0078] In this embodiment, the starting control device 20 is provided with a bypass passage 20 that bypasses the aforementioned pressure regulating valve 13 and connects the receiver tank 60 and the valve closing pressure receiving chamber 113 of the intake regulating valve 11.

[0079] This bypass passage 20 is configured to be openable and closable, and its passage area can be changed. This allows the opening and closing of the intake control valve 11 and the degree of opening to be adjusted by changing the start and stop of the introduction of compressed gas into the valve closing pressure receiving chamber 113 of the intake control valve 11, as well as the flow rate.

[0080] In order to enable opening and closing of the bypass passage 20 and changing the passage area, in the illustrated embodiment, the aforementioned bypass passage 20 is composed of a combination of two branch passages (first branch passage 21 and second branch passage 22), and electromagnetic valves (first solenoid valve 23 and second solenoid valve 24) are provided in each of the first branch passage 21 and the second branch passage 22. The passage area of ​​the bypass passage 20 is maximized when both the first and second solenoid valves 23 and 24 are open, the passage area can be narrowed by closing either the first or second solenoid valve 23 or 24, and the bypass passage 20 can be blocked by closing both the first and second solenoid valves 23 and 24.

[0081] In the illustrated embodiment, a configuration was described in which the bypass channel 20 is formed by two branch channels 21 and 22 and solenoid valves 23 and 24 provided in each branch channel 21 and 22. However, although not shown in the illustration, a configuration may be provided in which three or more branch channels and solenoid valves for opening and closing each branch channel are provided, so that the flow area of ​​the bypass channel 20 can be changed in multiple stages.

[0082] Furthermore, as shown in Figure 7, a single bypass channel 20 may be provided with an electrically operated flow control valve 25 whose opening degree can be adjusted by a motor or the like, thereby enabling stepless adjustment of the opening and closing of the bypass channel 20 and the flow channel area. The configuration of the bypass channel is not limited to the shown configuration.

[0083] In the embodiment shown in Figure 1, the first solenoid valve 23 provided in the aforementioned first branch passage 21 is a normally open (NO) type solenoid valve, and the second solenoid valve 24 provided in the aforementioned second branch passage 22 is a normally closed (NC) type solenoid valve. However, the configuration is not limited to this, and various combinations can be adopted.

[0084] In Figures 1, 6, and 7, reference numeral 27 denotes a three-way solenoid valve. Port C of this three-way solenoid valve 27 is connected to the auxiliary pressure receiving chamber 114 (spring chamber: see Figure 2) of the intake control valve 11 via a passage 28c. A passage 28a attached to port A is connected to the secondary side of the auxiliary on-off valve 30, which will be described later, and a passage 28b attached to port B is connected to the primary side of the intake control valve 11.

[0085] This configuration allows the auxiliary pressure-receiving chamber 114 of the intake control valve 11 to be selectively connected to either the intake passage 115 on the secondary side of the auxiliary on-off valve 30 or the primary side of the intake control valve 11 by switching the three-way solenoid valve 27. (See Figures 1 and 2)

[0086] Furthermore, the auxiliary pressure-receiving chamber 114 of the intake control valve 11 may be opened to the atmosphere via a silencer, and the aforementioned three-way solenoid valve 27 is not necessarily required.

[0087] [Auxiliary shut-off valve] The engine-driven compressor 1 of the present invention is further provided with an auxiliary on-off valve 30 that controls the opening and closing of the suction passage 115 of the compressor body 40.

[0088] The auxiliary on-off valve 30 may be provided separately from the intake control valve 11 described above, but in this embodiment, the auxiliary on-off valve 30 is integrally formed within a body (valve casing) common to the intake control valve 11 described above, so that the intake passage 115 can be opened and closed on the secondary side of the intake control valve 11.

[0089] In the embodiments shown in Figures 1 and 2, the auxiliary on-off valve 30 is formed by a combination of a butterfly valve 31, which is the valve body, and a bellows-type regulator 32 that opens and closes the butterfly valve 31. The butterfly valve 31 is constantly biased in the closing direction by the biasing force of a return spring 34 provided on the regulator 32, and the opening pressure receiving chamber 33 of the regulator 32, which is the opening pressure receiving chamber of the auxiliary on-off valve 30, is connected to the receiver tank 60 via an auxiliary control introduction circuit 65.

[0090] As a result, when the pressure in the receiver tank 60, which is introduced into the opening pressure receiving chamber 33 of the auxiliary shut-off valve 30, is less than the starting load reduction pressure P1, which is a predetermined low pressure relative to the rated pressure, the auxiliary shut-off valve 30 closes and closes the suction passage 115. When the pressure rises to or above the starting load reduction pressure P1, the auxiliary shut-off valve 30 starts opening and increases its opening degree in accordance with the rise in pressure in the receiver tank 60. Furthermore, when the pressure exceeds a predetermined oil supply amount securing pressure P2, which is lower than the rated pressure and higher than the starting load reduction pressure P1, and is the pressure necessary to supply lubricating oil to the compressor body 40, the auxiliary shut-off valve 30 is fully open.

[0091] In the illustrated embodiment, the auxiliary on-off valve 30 is provided on the secondary side of the intake control valve 11, but the auxiliary on-off valve 30 may also be provided on the primary side of the intake control valve 11.

[0092] In the configuration examples shown in Figures 2(A) and 2(B), the support shaft 35 of the butterfly valve 31 is rotatably supported in a shaft hole (not shown) provided in the aforementioned body 111. A lever 36 is attached to this support shaft 35, and a rod 37 provided on the regulator 32 is connected to this lever 36. As a result, the butterfly valve 31 can be opened and closed in accordance with the forward and backward movement of the rod 37 of the regulator 32.

[0093] In the illustrated embodiment, a bellows-type regulator 32 is used. When the pressure in the valve opening pressure receiving chamber 33 formed within the body of the regulator 32 increases, the cup-shaped bellows invert, moving the piston to the right in the diagram against the biasing force of the return spring 34, and increasing the protruding length of the rod 37 connected to the piston.

[0094] In the embodiments shown in Figures 1 and 2, when the butterfly valve 31 is closed, the space between the primary and secondary sides of the butterfly valve 31 is configured to communicate slightly through a minute communication passage 39.

[0095] Such a minute communication passage 39 may be formed by creating a through hole in the butterfly valve 31 as shown in Figure 2(A), or, as shown in Figure 2(B), a small gap δ may be created between the outer circumference of the butterfly valve 31 and the inner wall of the body 111 when the butterfly valve 31 is fully closed, and this gap δ may be used as the aforementioned minute communication passage 39. Furthermore, the configuration is not limited to those shown and various configurations can be adopted.

[0096] With the butterfly valve 31 closed, the amount of gas drawn into the compressor body 40 via the aforementioned micro-communication passage 39, that is, the flow area of ​​the micro-communication passage 39, should be sufficient to obtain the amount of intake air necessary to obtain the aforementioned starting load reduction pressure P1, which is the operating start pressure of the regulator 32 provided on the auxiliary shut-off valve 30, by drawing in the gas to be compressed via the micro-communication passage 39.

[0097] As described above, the valve opening pressure receiving chamber 33 of the regulator 32 of the auxiliary shut-off valve 30 is connected to the receiver tank 60 via the auxiliary control introduction circuit 65, as shown in Figure 1. When the pressure inside the receiver tank 60 rises to or above the starting load reduction pressure P1, which is the operating start pressure of the regulator 32, the butterfly valve 31 begins to open the intake passage 115 in accordance with the introduction pressure. When the pressure rises to or above the predetermined oil supply amount securing pressure P2, the regulator 32 fully opens the butterfly valve 31, and the intake control by the auxiliary shut-off valve 30 ends.

[0098] [Switches, sensors, etc.] The engine-driven compressor 1 of the present invention, configured as described above, is provided with a controller 50, which is a control device for controlling the operation of each part of the engine-driven compressor 1, and is also provided with switches that output electrical signals to the controller 50 (see Figure 3).

[0099] The aforementioned switches may include switches for controlling operations such as turning the main power of the engine-driven compressor 1 on and off, and starting and stopping the engine.

[0100] As an example, in the embodiment shown in Figure 3, such switches include a main switch 70 and a start switch 72, which are provided on the control panel of the engine-driven compressor 1.

[0101] The main switch 70 is used to switch the main power supply of the engine-driven compressor 1 between "ON" and "OFF". "OFF" is the stopped state in which power is stopped to all parts of the engine-driven compressor 1, while "ON" is the so-called "accessory position", in which power is supplied to the engine, electronic control devices such as the controller 50, various sensors and instruments, etc.

[0102] Furthermore, the start switch 72 is a switch for starting the engine. In this embodiment, it is configured as a push-button switch, and when it is pressed for a predetermined time (for example, 1 second) or longer, power is supplied to the engine's starter motor, and the engine starts.

[0103] In this configuration of an engine-driven compressor 1 equipped with a main switch 70 and a start switch 72, the engine-driven compressor 1 can be started and operated continuously by switching the main switch 70 from the "OFF" position to the "ON" position and then pressing and holding the start switch 72 to start the engine. The engine-driven compressor 1 can also be stopped by switching the main switch 70 from the "ON" position to the "OFF" position.

[0104] Furthermore, the switches for starting and stopping the engine-driven compressor 1 are not limited to a configuration in which a main switch 70 and a start switch 72 are provided separately, as described above. Various configurations can be adopted as long as they can turn the accessory (main switch) ON and OFF, and also turn the starter motor ON and OFF. The switches for turning the accessory ON and OFF and the starter motor ON and OFF may be made up of known key switches, etc., which can be switched from the OFF position to the ON position (accessory position) and then to the start position where the engine's starter motor is rotated by inserting and rotating a key.

[0105] 〔controller〕 The engine-driven compressor 1 of the present invention, configured as described above, is equipped with a controller 50, which is an electronic control device, that controls the operation of the engine's starter motor, the first solenoid valve 23, the second solenoid valve 24, and the three-way solenoid valve 27 based on the operation of the switches mentioned above.

[0106] The controller 50 performs the following control based on the operating status of the switches 70 and 72 mentioned above, the count of the built-in timer, and detection signals from sensors provided as needed.

[0107] (1) Preparation for starting When the operator switches the main switch 70 from "OFF" to "ON", power is supplied to each part of the engine-driven compressor 1, and the controller 50 starts up.

[0108] (2) Starting load reduction operation Following the aforementioned ON state of the main switch 70, when the operator presses and holds the start switch 72, the controller 50 energizes (ON) the second solenoid valve 24 and opens it, while keeping the first solenoid valve 23 de-energized (OFF), i.e., in the open state.

[0109] In this way, by connecting the valve closing pressure receiving chamber 113 of the intake control valve 11 to the receiver tank 60 via the bypass passage 20 (first and second branch passages 21 and 22), the control of the intake control valve 11 by the pressure regulating valve 13 is disabled. Even when the pressure in the receiver tank 60 is below the rated pressure and has not reached the operating pressure of the pressure regulating valve 13, it is possible to introduce the compressed gas in the receiver tank 60 as the operating pressure into the valve closing pressure receiving chamber 113 of the intake control valve 11 and perform the valve closing operation.

[0110] Thus, when the first and second solenoid valves 23 and 24 are opened, the closed pressure-receiving chamber 113 of the intake control valve 11 is connected to the receiver tank 60 via the bypass passage 20, and the open pressure-receiving chamber 33 of the auxiliary on-off valve 30 is connected to the receiver tank 60 via the auxiliary control introduction circuit 65. However, since the pressure inside the receiver tank 60 at this time is atmospheric pressure or close to atmospheric pressure, the intake control valve 11 is in the open state and the auxiliary control valve 30 is in the closed state (see time A in Figure 4).

[0111] In the configuration shown in Figure 1, which includes a three-way solenoid valve 27, the controller 50 further switches the three-way solenoid valve 27 to a position where the auxiliary pressure-receiving chamber 114 of the intake control valve 11 communicates with the intake passage 115 on the secondary side of the auxiliary on-off valve (a position where ports CA communicate).

[0112] Subsequently, the controller 50 starts the engine by rotating the starter motor, thereby initiating reduced starting load operation (see AC in Figure 4).

[0113] When the engine is started, the pressure inside the receiver tank 60 is at or close to atmospheric pressure, and the intake control valve 11 is open. However, the intake passage 115 of the compressor body 40 is closed by the normally closed auxiliary on-off valve 30, so the engine can be started with the load on the engine reduced as much as possible.

[0114] When the engine is started in this manner, the screw rotor of the compressor body 40 connected to the engine begins to rotate, and the compressor body 40 draws in air from the intake passage 115 through the minute communication passage 39 provided in the auxiliary on-off valve 30 to generate compressed gas. The compressed gas thus generated is introduced into the receiver tank 60, causing the pressure inside the receiver tank 60 to rise.

[0115] When the pressure inside the receiver tank 60 rises above the operating pressure of the intake control valve 11, the intake control valve 11 closes, preventing intake through the minute communication passage 39 provided in the auxiliary on-off valve 30, and stopping the rise in the internal pressure of the receiver tank 60 (time B in Figure 4).

[0116] Therefore, by continuing this operating state, for example, until a predetermined time X (sec) count by a timer is completed, it is possible to perform a starting load reduction operation while maintaining the pressure in the receiver tank 60 below a predetermined starting load reduction pressure P1.

[0117] Furthermore, in the configuration with the three-way solenoid valve 27 as shown in Figure 1, when the engine is started by operating the three-way solenoid valve 27 by the controller 50, the auxiliary pressure-receiving chamber 114 of the intake control valve 11 is connected to the intake passage 115 on the secondary side of the auxiliary on-off valve 30. As the compressor body 40 starts to take in air, the negative pressure generated in the intake passage 115 allows for smooth exhaust of the auxiliary pressure-receiving chamber 114, thereby enabling the intake control valve 11 to close smoothly.

[0118] (3) Operation to ensure sufficient fuel supply When the controller 50 completes the countdown of a predetermined time by its built-in timer, it starts energizing the first solenoid valve 23 and closing the first solenoid valve 23 to start the operation to ensure the amount of fuel supplied.

[0119] Furthermore, in the configuration equipped with a three-way solenoid valve 27 as shown in Figure 1, the controller 50 further operates the three-way solenoid valve 27 to open the auxiliary pressure receiving chamber 114 of the intake control valve 11 to the atmosphere by connecting it to the primary side of the intake control valve 11.

[0120] When the first solenoid valve 23 is closed, the flow area of ​​the bypass flow path 20 narrows by the amount of the first branch flow path 21 that is blocked. As a result, the amount of compressed gas introduced into the pressure receiving chamber 113 of the intake control valve 11 decreases, causing the intake control valve 11, which was completely closed, to open to a predetermined opening degree corresponding to the decrease in the amount of compressed gas introduced (time C in Figure 4).

[0121] When the intake control valve 11 is opened, the intake of the gas to be compressed through the minute communication passage 39 of the auxiliary on-off valve 30 begins, and the compressor body 40 resumes the generation of compressed gas, causing the pressure inside the receiver tank 60 to start rising (time C in Figure 4).

[0122] As a result, the pressure inside the receiver tank 60 rises to or above the starting load reduction pressure P1, causing the auxiliary shut-off valve 30 to begin opening, and the degree of opening of the auxiliary shut-off valve 30 increases in accordance with the rise in pressure inside the receiver tank 60 (time CD in Figure 4).

[0123] On the other hand, as the pressure in the receiver tank 60 increases, the pressure of the compressed gas introduced into the valve closing pressure receiving chamber 113 of the intake control valve 11 via the second branch passage 22 also increases. Therefore, as the pressure in the receiver tank 60 rises, the intake control valve 11 starts closing again, and closes when the pressure in the receiver tank 60 reaches the predetermined fuel supply pressure P2 (time CD in Figure 4).

[0124] By closing the intake control valve 11, the pressure inside the receiver tank 60 is maintained at the fuel supply amount securing pressure P2, and the fuel supply amount securing operation continues in this state until a predetermined time Y (sec) has elapsed.

[0125] (4) Normal operation When the timer counts that a predetermined time Y (sec) has elapsed since the start of the fuel supply maintenance operation, the controller 50 stops (OFF) the power supply to the second solenoid valve 24, thereby closing the second solenoid valve 24 and blocking the second branch passage 22, which in turn cuts off communication between the receiver tank 60 and the valve closing pressure receiving chamber 113 of the intake control valve 11 through all the branch passages of the bypass flow path 20.

[0126] As a result, the deactivation of the control of the intake control valve 11 by the pressure regulating valve 13 in the control flow path 12 is released, and the opening and closing control of the intake control valve 11 by the pressure regulating valve 13 is started.

[0127] In the configuration shown in Figure 1, which includes a three-way solenoid valve 27, the controller 50 keeps the switching position of the three-way solenoid valve 27 in the state during fuel supply amount maintenance operation. Therefore, the three-way solenoid valve 27 maintains a state in which the auxiliary pressure receiving chamber 114 of the intake control valve 11 is connected to the primary side of the intake control valve 11 and opened to the atmosphere.

[0128] During fuel supply maintenance operation, the pressure in the receiver tank 60 is maintained at a fuel supply maintenance pressure P2 which is lower than the rated pressure, and the pressure regulating valve 13 is in a state where the control passage 12 is closed. Therefore, when the introduction of operating pressure via the second branch passage 22 is stopped by the closing of the second solenoid valve 24, the intake control valve 11 opens fully (time E in Figure 4).

[0129] As a result, the compressor body 40 begins to draw in the gas to be compressed and generate the compressed gas, causing the pressure inside the receiver tank 60 to start rising and exceeding the oil supply pressure P2, which causes the auxiliary shut-off valve 30 to open completely.

[0130] As a result, the intake control of the compressor body 40 by the auxiliary on-off valve 30 ends, and the system transitions to normal operation in which the intake control of the compressor body 40 is performed solely by the opening and closing control of the intake control valve 11 by the pressure regulating valve 13 installed in the control passage 12.

[0131] Subsequently, when the pressure inside the receiver tank 60 exceeds the rated pressure, the intake control valve 11 closes (time F in Figure 4), and intake control is performed to bring the pressure inside the receiver tank 60 closer to the rated pressure.

[0132] In this configuration of the present invention, by performing the aforementioned oil supply amount securing operation before transitioning to normal operation, the pressure in the receiver tank 60 is raised to a predetermined oil supply amount securing pressure P2. In this state, even when the engine-driven compressor 1 transitions to normal operation under full load by fully opening the intake control valve 11 and the auxiliary on-off valve 30, it is possible to effectively prevent abnormal increases in discharge temperature due to insufficient lubrication oil supply.

[0133] [Comparison of effects] Figure 5 shows a graph comparing the state of pressure change in the receiver tank of the engine-driven compressor 1 of the present invention, which implements the operation control method described above, with that of the engine-driven compressor 300 of the aforementioned Patent Document 1.

[0134] As shown in Figure 5, in the engine-driven compressor 1 that implements the operation control method of the present invention, the pressure inside the receiver tank at startup is maintained at a lower level compared to the engine-driven compressor of Patent Document 1.

[0135] A low pressure in the receiver tank at startup indicates that the amount of compressed gas generated at startup is small, and therefore the load on the engine at startup is low. It was confirmed that by implementing the operation control method of the present invention, the starting load can be further reduced while maintaining the functions of the engine-driven compressor described in Patent Document 1.

[0136] [Example of modification] Example of modification of an auxiliary shut-off valve In the engine-driven compressor 1 of the present invention, as described above with reference to Figure 1, the case in which the auxiliary on-off valve 30 is configured to open and close using the pressure in the receiver tank 60 as the operating pressure was used as an example.

[0137] In contrast, the engine-driven compressor 1 shown in Figure 6 is equipped with an electric motor 32' that operates the auxiliary on-off valve 30, and the controller 50 controls the operation of the auxiliary on-off valve 30 by operating the electric motor 32'.

[0138] In this case, the controller 50 may be configured to control the opening and closing operation of the auxiliary on-off valve 30 at a predetermined timing, or a pressure sensor may be provided to detect the pressure in the receiver tank 60, and the operation of the auxiliary on-off valve 30 may be controlled according to the pressure in the receiver tank 60 detected by the pressure sensor.

[0139] In the embodiment described with reference to Figure 1, the auxiliary shut-off valve 30 was opened using the pressure inside the receiver tank 60 as the operating pressure. Therefore, a configuration was adopted in which a small communication passage 39 for the auxiliary shut-off valve 30 was provided in order to ensure the operating pressure of the auxiliary shut-off valve 30.

[0140] In contrast, in this embodiment, by adopting a configuration in which the auxiliary on-off valve 30 is opened and closed by an electric motor 32', it becomes unnecessary to secure operating pressure, and thus it is no longer necessary to provide a minute communication passage 39. This makes it possible to start the engine with the intake passage of the compressor body 40 completely closed, further reducing the starting load.

[0141] Furthermore, since the intake volume of the compressor body 40 can be adjusted by adjusting the opening degree of the auxiliary on-off valve 30, it is possible to omit the configuration (for example, the second branch passage 22 and the second solenoid valve 24) that is provided on the bypass passage 20 side to adjust the opening degree of the intake control valve 11. [Explanation of symbols]

[0142] 1. Engine-driven compressor 10 Intake adjustment device 11. Intake control valve 111 Body (valve box) 112 Cylinder 113 Valve-closing pressure-receiving chamber 114 Auxiliary pressure receiving room 114a Spring 115 Suction flow path 115a Valve seat 116 Valve body 116a,116a' Valve stem 116b Spring 117 sleeves 118 End plate 119 Pressure-receiving body 119a Valve stem 12 Control channel 13 Pressure regulating valve 20 Starting control device (bypass flow path) 21 1st tributary channel 22 2nd tributary channel 23. First solenoid valve (electromagnetic on / off valve) 24. Second solenoid valve (electromagnetic on / off valve) 25 Flow control valve 27 Three-way solenoid valve 28a, 28b, 28c channel 30 Auxiliary shut-off valve 31 Butterfly valve (valve body) 32 Regulator 32' Electric Motor 33. Open valve pressure receiving chamber 34 Return Spring 35 Spindle 36 Lever 37 Rods 39 Micro communication path 40 Compressor body 41 Air intake 50 Controllers 60 Receiver Tank 61 Fueling channel 62 Oil Cooler 63 Oil filter 65. Introduction circuit for auxiliary control 70 Main Switch 72 Starting switch 300 Engine-driven compressor 310 Intake Adjustment Device 311 Intake control valve 312 Control channel 313 Pressure regulating valve 320 Starting load reduction device (bypass flow path) 321,322 Bypass channel 323,324 Bypass valve 326 Block Manifold 327 Common channel 340 Compressor Unit 341 Air intake 360 Receiver Tank 361 Fueling channel 362 Oil Cooler P1 Starting load reduction pressure P2 Pressure to ensure fuel supply

Claims

1. In an engine-driven compressor operation control method, the method comprises an engine, an oil-cooled compressor body driven by the engine, a receiver tank that introduces a gas-liquid mixed fluid of compressed gas and lubricating oil discharged from the compressor body and separates it into compressed gas and lubricating oil, and supplies the separated lubricating oil to the compressor body using its internal pressure, an intake control valve that controls the intake of air to the compressor body, a control passage that connects the pressure-receiving chamber of the intake control valve and the receiver tank, and a pressure regulating valve that opens and closes the control passage according to the pressure in the receiver tank, wherein during normal operation, the pressure regulating valve controls the opening and closing operation of the intake control valve by opening the control passage when the pressure in the receiver tank is above a predetermined rated pressure and closing the control passage when it is below the rated pressure, thereby controlling the intake of air to the compressor body. An auxiliary on / off valve is provided to open and close the intake passage that communicates with the intake port of the compressor body, With the control of the intake control valve by the pressure regulating valve disabled and the auxiliary on / off valve closed, the engine is started and a starting load reduction operation is performed in which the pressure in the receiver tank is maintained at a pressure less than the predetermined starting load reduction pressure, which is less than the rated pressure. When the termination conditions for the starting load reduction operation are met, the intake control valve is opened to less than fully open, and the auxiliary on-off valve is opened to raise the pressure in the receiver tank to a level below the rated pressure but higher than the starting load reduction pressure, and to a predetermined oil supply pressure necessary to ensure oil supply to the compressor body, and an oil supply supply maintenance operation is performed to maintain this oil supply pressure. A method for controlling the operation of an engine-driven compressor, characterized in that when the termination conditions for the fuel supply amount securing operation are met, the deactivation is released, the opening and closing control of the intake control valve is started by the pressure regulating valve, and the auxiliary opening and closing valve is fully opened, and the operation transitions to the normal operation.

2. A bypass channel with a changeable flow area is provided to bypass the pressure regulating valve and enable communication between the receiver tank and the valve-closing pressure-receiving chamber of the intake regulating valve. By connecting the receiver tank and the valve-closing pressure-receiving chamber of the intake control valve with the bypass flow path that maximizes the flow area, the engine is started, and the starting load reduction operation is performed with the intake control valve closed as the engine starts. By narrowing the flow area of ​​the bypass passage and opening the intake control valve to less than fully open, the starting load reduction operation is terminated and the fuel supply amount securing operation is started, The operation control method for an engine-driven compressor according to claim 1, characterized in that the oil supply amount securing operation is terminated and the system transitions to normal operation by blocking communication between the receiver tank and the valve-closed pressure-receiving chamber of the intake control valve through the bypass passage.

3. The method for controlling the operation of an engine-driven compressor according to claim 1 or 2, characterized in that the auxiliary on-off valve is fully closed when the pressure in the receiver tank is less than the starting load reduction pressure, starts opening when it becomes equal to or greater than the starting load reduction pressure, and fully opens when it exceeds the oil supply amount securing pressure.

4. When the auxiliary on-off valve is closed, a small connecting passage is provided that connects the primary and secondary sides of the auxiliary on-off valve, The method for controlling the operation of an engine-driven compressor according to claim 3, characterized in that the opening and closing of the auxiliary on-off valve is performed using the pressure in the receiver tank as the operating pressure.

5. The method for controlling the operation of an engine-driven compressor according to claim 1 or 2, characterized in that the opening and closing of the auxiliary on-off valve is performed by an electric motor.

6. The method for controlling the operation of an engine-driven compressor according to claim 2, characterized in that at least a portion of the bypass flow path is formed by a collection of multiple branch flow paths arranged in parallel, each of the branch flow paths can be opened and closed, and the flow area of ​​the bypass flow path is changed by changing the number of branch flow paths that are opened or closed.

7. The method for controlling the operation of an engine-driven compressor according to claim 2, characterized in that the flow area of ​​the bypass flow path is changed by operating a flow control valve provided in the bypass flow path.

8. In an engine-driven compressor, the compressor comprises an engine, an oil-cooled compressor body driven by the engine, a receiver tank that introduces a gas-liquid mixed fluid of compressed gas and lubricating oil discharged from the compressor body and separates it into compressed gas and lubricating oil, and supplies the separated lubricating oil to the compressor body using its internal pressure, an intake control valve that controls the intake of air to the compressor body, a control passage that connects the pressure-receiving chamber of the intake control valve and the receiver tank, and a pressure regulating valve that opens and closes the control passage according to the pressure in the receiver tank, wherein during normal operation, the pressure regulating valve controls the opening and closing operation of the intake control valve by opening the control passage when the pressure in the receiver tank is above a predetermined rated pressure and closing the control passage when it is below the rated pressure, thereby controlling the intake of air to the compressor body. A starting control device that controls the opening and closing of the intake control valve by disabling the opening and closing control of the intake control valve by the pressure regulating valve, An auxiliary on / off valve that opens and closes an intake passage that communicates with the intake port of the compressor body, The engine-driven compressor is equipped with a controller that controls the operation of each part of the engine. The auxiliary on-off valve is configured to close when the pressure in the receiver tank is below a predetermined starting load reduction pressure, which is below the rated pressure, to open when it is above the starting load reduction pressure, and to fully open when it is below the rated pressure, above the starting load reduction pressure, and exceeds a predetermined oil supply amount securing pressure, which is the pressure necessary to supply oil to the compressor body. The aforementioned controller, The engine is started with the start control device in which the control of the intake control valve by the pressure regulating valve is disabled, and the start load reduction operation is performed in which the pressure in the receiver tank is maintained at a pressure less than the predetermined start load reduction pressure, which is less than the rated pressure. When the termination conditions for the starting load reduction operation are met, the starting control device is operated to open the intake control valve to less than fully open, raising the pressure in the receiver tank to the oil supply amount securing pressure, and an oil supply amount securing operation is performed to maintain that pressure. An engine-driven compressor characterized in that, when the termination conditions for the fuel supply amount securing operation are met, the deactivation by the start control device is released, the control of the intake control valve by the pressure regulating valve is started to raise the pressure in the receiver tank to above the fuel supply amount securing pressure, and the system transitions to normal operation.

9. As the starting control device, a bypass flow path with a changeable flow path area is provided, which bypasses the pressure regulating valve and enables communication between the receiver tank and the closed pressure receiving chamber of the intake regulating valve. The aforementioned controller, By connecting the receiver tank and the valve-closing pressure-receiving chamber of the intake control valve with the bypass flow path that maximizes the flow area, the engine is started, and the starting load reduction operation is performed with the intake control valve closed as the engine starts. By narrowing the flow area of ​​the bypass passage, the intake control valve is opened to an opening degree less than fully open, thereby transitioning from the starting load reduction operation to the fuel supply amount securing operation, The engine-driven compressor according to claim 8, characterized in that the transition from the oil supply amount securing operation to the normal operation is performed by blocking communication between the receiver tank and the valve-closed pressure-receiving chamber of the intake control valve through the bypass passage.

10. The auxiliary on-off valve is configured as a normally closed on-off valve that opens using the pressure inside the receiver tank as the operating pressure, The engine-driven compressor according to claim 8 or 9, characterized in that a minute connecting passage is provided that connects the primary side and the secondary side of the auxiliary on-off valve when the auxiliary on-off valve is closed.

11. The auxiliary on-off valve is provided with an electric motor that performs the opening and closing operation of the valve body of the auxiliary on-off valve. The aforementioned controller, The engine-driven compressor according to claim 8 or 9, characterized in that the operation of the electric motor is controlled to control the opening and closing of the auxiliary on-off valve.

12. At least a portion of the bypass channel is formed by a collection of multiple branch channels arranged in parallel, and an electromagnetic valve is provided to open and close each of the branch channels. The aforementioned controller, The engine-driven compressor according to claim 9, characterized in that the flow area of ​​the bypass flow path is changed by changing the number of electromagnetic on / off valves that are opened or closed.

13. An electrically operated flow control valve is provided in the bypass channel. The aforementioned controller, The engine-driven compressor according to claim 9, characterized in that the flow area of ​​the bypass channel is changed by changing the opening degree of the flow control valve.

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