CN111852654B

CN111852654B - Monitoring system

Info

Publication number: CN111852654B
Application number: CN202010322094.XA
Authority: CN
Inventors: 森勇人; 猿渡洋平; 穴井恒平; 柴田隼平; 赤荻祐亮
Original assignee: Hitachi Shipbuilding Marine Prime Motors Co ltd
Current assignee: Hitachi Shipbuilding Marine Prime Motors Co ltd
Priority date: 2019-04-25
Filing date: 2020-04-22
Publication date: 2023-08-08
Anticipated expiration: 2040-04-22
Also published as: TW202039993A; KR20200125516A; CN111852654A; JP2020180586A; JP7208099B2

Abstract

A monitoring system (76) of the present invention includes a throttle valve (75), a delivery flow path (760), a pressure sensor (765), and a detection unit (767). The throttle valve (75) has an inlet and an outlet (755) for drive oil from the first hydraulic drive line (71). The throttle valve (75) receives the pressure of the drive oil to close the outlet (755) when the drive oil is pressurized, and opens the outlet (755) when the drive oil is not pressurized to exhaust the first hydraulic drive line (71). The delivery flow path 760 guides the drive oil flowing out from the outlet 755 of the throttle valve 75. A pressure sensor (765) measures the pressure of the drive oil flowing out from the outlet (755) in the delivery flow path (760). A detection unit (767) detects an abnormality in the gas content in the first hydraulic drive line (71) based on the measurement value of the pressure sensor (765).

Description

Monitoring system

Technical Field

The present invention relates to a monitoring system for monitoring an oil pressure drive line of a diesel engine.

Background

Conventionally, in a marine diesel engine, an exhaust port for discharging gas combusted in a combustion chamber and an exhaust valve for opening and closing the exhaust port are provided, and operation monitoring of the exhaust valve driven by a hydraulic pressure is performed by a stroke sensor (stroke sensor). However, monitoring of the oil pressure drive line driving the exhaust valve is not generally performed.

On the other hand, japanese patent No. 5835004 (document 1) proposes the following technique: in a gasoline engine for a vehicle, the pressure of oil supplied to a hydraulic drive component is detected, and when the fluctuation range of the pressure pulsation of the oil is smaller than a threshold value, it is estimated that the oil pump is in an intake state and the bubble rate of the oil increases. In addition, japanese patent No. 4730100 (document 2) proposes the following technique: in a brake control device for a vehicle, the pressure of a working fluid supplied to a wheel cylinder (wheel cylinder) for applying braking force to a wheel is detected, and the presence or absence of air mixing into the working fluid and the air mixing amount are determined based on the pressure fluctuation of the working fluid.

In the monitoring devices of documents 1 and 2, pressure fluctuations of the drive oil pumped out from the hydraulic drive line and supplied to the drive target (for example, wheel cylinder) are measured, and the mixing of air into the drive oil is detected based on the measurement result. However, since the flow rate of the drive oil supplied to the drive target is relatively large and the pressure is relatively high, it is difficult to exhibit the influence of air mixing into the drive oil, and it is difficult to accurately detect air mixing in the monitoring device. If the amount of air mixed is increased to a state where the air mixed can be detected by the monitoring device, there is a possibility that an abnormality has occurred in the operation of the driving object.

Disclosure of Invention

The present invention is directed to a monitoring system for monitoring a hydraulic drive line of a diesel engine, and an object of the present invention is to realize early detection of abnormality in the gas content in the hydraulic drive line.

A monitoring system according to a preferred embodiment of the present invention includes: a throttle valve (throttle valve) having an inlet and an outlet for drive oil from a hydraulic drive line, the throttle valve being configured to close the outlet by receiving pressure of the drive oil when the drive oil is pressurized and to open the outlet when the drive oil is not pressurized, thereby exhausting the hydraulic drive line; a discharge flow path for guiding the drive oil flowing out from the outlet of the throttle valve; a pressure sensor that measures a pressure of the driving oil flowing out from the outlet in the lead-out flow path; and a detection unit that detects an abnormality in the gas content in the hydraulic drive line based on the measurement value of the pressure sensor.

According to the present invention, early detection of abnormality in the gas content rate in the hydraulic drive line can be achieved.

Preferably, the detection unit detects an abnormality in the gas content rate in the hydraulic drive line by comparing a measured value of the pressure sensor with a reference value in a normal state for a peak pressure of the drive oil immediately before the outlet of the throttle valve is closed.

More preferably, the detection unit detects that the gas content in the hydraulic drive line is abnormal when the peak pressure continuously decreases in a plurality of cycles.

Preferably, the measurement by the pressure sensor is performed based on a drive control signal for a drive target of the hydraulic drive line.

Preferably, the discharge passage is provided independently of a drain line through which the drive oil discharged from a portion of the hydraulic drive line other than the throttle valve flows.

Preferably, the detection unit obtains the gas content in the hydraulic drive line based on the measured value of the pressure sensor.

More preferably, the monitoring system further includes an alarm unit that gives an alarm when the gas content in the hydraulic drive line acquired by the detection unit is greater than a predetermined threshold.

Preferably, the driving object of the oil pressure driving line includes an exhaust valve of a diesel engine.

The above and other objects, features, aspects and advantages will be elucidated with reference to the detailed description of the invention described hereinafter with reference to the accompanying drawings.

Drawings

Fig. 1 is a diagram showing a structure of a diesel engine according to an embodiment.

Fig. 2 is a cross-sectional view showing the vicinity of the exhaust valve hydraulic cylinder.

Fig. 3 is a cross-sectional view showing a throttle valve.

Fig. 4 is a cross-sectional view showing a throttle valve.

Fig. 5 is a diagram showing a reference fluctuation of the pressure of the drive oil.

Fig. 6 is a diagram showing a configuration of the monitor.

Fig. 7 is a diagram showing pressure fluctuations of the drive oil in an abnormal state.

Fig. 8 is a diagram showing pressure fluctuations of the drive oil in an abnormal state.

[ description of symbols ]

1: diesel engine

25: exhaust valve

71: first oil pressure driving pipeline

75: throttle valve

76: monitoring system

754: inlet (of throttle valve)

755: outlet (of throttle valve)

760: guide-out flow path

765: pressure sensor

767: detection unit

768: alarm unit

Detailed Description

Fig. 1 is a diagram showing a structure of a diesel engine 1 according to an embodiment of the present invention. The diesel engine 1 illustrated in fig. 1 is a two-stroke engine serving as a main engine of a ship. In fig. 1, a part of a diesel engine 1 is shown in cross section.

The diesel engine 1 includes: the cylinder 2, the piston 3, the exhaust valve 25, the exhaust passage 241, the exhaust pipe 42, the supercharger 5, the air cooler 43, the scavenging pipe 41, the scavenging chamber 231, the fuel supply mechanism 6, and the hydraulic drive mechanism 7.

The cylinder 2 includes a cylinder liner 21 and a cylinder head 22. The cylinder liner 21 is a substantially cylindrical member. The cylinder head 22 is a substantially cap-cylindrical member attached to an upper portion of the cylinder liner 21. The cylinder head 22 covers an upper opening of the cylinder liner 21. A plurality of through holes are circumferentially provided near the lower end of the cylinder liner 21. The through holes are scavenging ports 23 for supplying scavenging gas, which will be described later, into the cylinder 2. A scavenging chamber 231 is disposed around the scavenging port 23. The scavenging port 23 is connected to the scavenging pipe 41 via a scavenging chamber 231.

An exhaust port 24 for exhausting the gas in the cylinder 2 to the outside of the cylinder 2 is provided at the upper end portion of the cylinder head 22. The shape of the exhaust port 24 in a plan view (i.e., the shape viewed from the up-down direction in fig. 1) is substantially circular. Further, the vertical direction in fig. 1 does not necessarily coincide with the gravitational direction.

The exhaust valve 25 is disposed at a position overlapping the exhaust port 24 in the vertical direction, and opens and closes the exhaust port 24. The exhaust valve 25 includes a valve body 251 and a valve stem 252. The valve body 251 is a substantially conical portion located below the exhaust port 24. The valve body 251 has a larger diameter in plan view than the exhaust port 24 in plan view. The valve rod 252 is a substantially cylindrical portion extending upward from the upper end of the valve body 251. The upper end portion of the valve rod 252 is housed in an exhaust valve hydraulic cylinder 253 provided above the cylinder 2, and is supported so as to be movable in the up-down direction.

The exhaust valve 25 is moved in the up-down direction by the hydraulic drive mechanism 7. As shown by the solid line in fig. 1, the exhaust port 24 is opened in a state where the valve body 251 of the exhaust valve 25 is separated downward from the exhaust port 24, and the gas in the cylinder 2 is discharged to the outside of the cylinder 2 through the exhaust port 24. On the other hand, in a state where the valve body 251 is located at the position indicated by the two-dot chain line in fig. 1, the valve body 251 contacts the peripheral edge portion of the exhaust port 24 to close the exhaust port 24, and therefore, the gas in the cylinder 2 is not discharged from the exhaust port 24. In the following description, the position of the exhaust valve 25 shown by the solid line in fig. 1 is referred to as "open position", and the position of the exhaust valve 25 shown by the two-dot chain line is referred to as "closed position". The exhaust valve 25 is movable in the up-down direction between an open position and a closed position above the open position.

In a state where the exhaust valve 25 is in the open position, the gas discharged from the exhaust port 24 to the outside of the cylinder 2 (hereinafter referred to as "exhaust") is guided to the exhaust pipe 42 via the exhaust path 241. In the actual diesel engine 1, a plurality of cylinders 2 are arranged in parallel, and the plurality of cylinders 2 are connected to one scavenging pipe 41 and one exhaust pipe 42.

The exhaust gas in the exhaust pipe 42 is sent to a turbocharger 5 as a turbocharger, and is supplied to a turbine 51 of the turbocharger 5. The exhaust gas used for rotation of the turbine 51 is discharged to the outside of the diesel engine 1 via a reduction catalyst or the like (not shown) for reducing Nitrogen Oxides (NOX). In the compressor 52 of the supercharger 5, intake air (air) taken in from the outside of the diesel engine 1 is pressurized by the rotational force generated by the turbine 51. The pressurized air (hereinafter referred to as "scavenging air") is cooled by a refrigerant such as seawater in the air cooler 43, and then supplied into the scavenging pipe 41. In this way, the supercharger 5 pressurizes the intake air with the exhaust gas to generate the scavenging gas.

The piston 3 is movable in the cylinder 2 in the up-down direction in fig. 1. In fig. 1, the position of the piston 3 shown by the two-dot chain line is the top dead center, and the position of the piston 3 shown by the solid line is the bottom dead center. The piston 3 comprises a piston head 31 and a piston rod 32. The piston head 31 is a thick, substantially disk-shaped portion into which the cylinder liner 21 is inserted. The piston rod 32 has a substantially cylindrical shape and an upper end connected to the lower surface of the piston head 31. The lower end of the piston rod 32 is connected to a crank mechanism, not shown. In the diesel engine 1 illustrated in fig. 1, a space surrounded by the cylinder liner 21, the cylinder head 22, the exhaust valve 25, and the upper surface of the piston head 31 is a combustion chamber 20 for combustion gas.

The fuel supply mechanism 6 includes a fuel injection portion 61 and a fuel supply pump 62. The fuel injection portion 61 is a nozzle attached to the cylinder head 22 with its tip portion facing the combustion chamber 20. The fuel supply pump 62 is connected to a fuel tank (not shown) via a fuel pipe, and sends fuel in the fuel tank to the fuel injection unit 61. The fuel injection unit 61 injects the fuel supplied from the fuel supply pump 62 into the combustion chamber 20. The fuel supply pump 62 is also driven by the hydraulic drive mechanism 7.

Next, the operation of the diesel engine 1 will be described. In the diesel engine 1, when the piston 3 is located near the top dead center while rising from the bottom dead center, the exhaust valve 25 is located at the closed position, and the exhaust port 24 is closed. Therefore, the gas (scavenging gas, as described later) in the combustion chamber 20 is compressed. Then, the fuel is injected from the fuel injection portion 61 into the combustion chamber 20, and the vaporized fuel is self-ignited, so that the gas in the combustion chamber 20 burns (i.e., explodes). Thereby, the piston 3 is pressed downward and moves toward the bottom dead center. The gas in the combustion chamber 20 is not necessarily self-ignited, and ignition of the gas in the combustion chamber 20 may be performed using a spark plug or the like.

After combustion of the gas in the combustion chamber 20, the exhaust valve 25 descends from the closed position to the open position and the exhaust port 24 opens before the piston 3 reaches the bottom dead center. Thereby, the discharge of the burnt gas in the combustion chamber 20 is started. As described above, the gas (i.e., exhaust gas) discharged from the combustion chamber 20 is supplied to the turbine 51 of the supercharger 5 via the exhaust path 241 and the exhaust pipe 42, and is discharged to the outside of the diesel engine 1 through the reduction catalyst or the like.

When the piston 3 descends to the vicinity of the bottom dead center, the upper surface of the piston head 31 moves to a position lower than the scavenging port 23, the scavenging port 23 is opened, and the combustion chamber 20 and the scavenging chamber 231 communicate via the scavenging port 23. Thereby, the scavenging gas in the scavenging chamber 231 is supplied into the combustion chamber 20.

After reaching bottom dead center, the piston 3 is turned upward. The upper surface of the piston head 31 rises to a position higher than the scavenging port 23, whereby the scavenging port 23 is closed, and the supply of scavenging gas into the combustion chamber 20 is stopped. In turn, the exhaust port 24 is closed by an exhaust valve 25, and the combustion chamber 20 is closed. By further raising the piston 3, the scavenging gas in the combustion chamber 20 is compressed. When the piston 3 reaches the vicinity of the top dead center, fuel is injected from the fuel injection portion 61 into the combustion chamber 20, and the combustion is generated in the combustion chamber 20. In the diesel engine 1, the operation is repeated.

Next, the hydraulic drive mechanism 7 will be described in detail. The hydraulic drive mechanism 7 includes a hydraulic drive line 71, a hydraulic drive line 72, a drive oil tank 73, a drive oil pump 74, and a drive oil replenishment unit 77. The drive oil tank 73 stores drive oil. The drive oil pump 74 sends the drive oil in the drive oil tank 73 to the hydraulic drive line 71 and the hydraulic drive line 72. The hydraulic drive line 71 is connected to the exhaust valve hydraulic cylinder 253, and drives the exhaust valve 25. The hydraulic drive line 72 is connected to the fuel supply mechanism 6, and drives the fuel supply pump 62. That is, the hydraulic drive line to which the exhaust valve 25 is driven is "the first hydraulic drive line 71". The hydraulic drive line to which the fuel supply pump 62 is driven is referred to as "second hydraulic drive line 72". The drive oil supply unit 77 supplies drive oil to the drive oil tank 73. The drive oil replenishment unit 77 continuously measures, for example, the amount of drive oil stored in the drive oil tank 73, and if the amount of drive oil is smaller than a predetermined amount, replenishment of the drive oil tank 73 with drive oil is performed.

Fig. 2 is an enlarged cross-sectional view showing the vicinity of the exhaust valve hydraulic cylinder 253. Fig. 2 shows the configuration of the first hydraulic drive line 71. The first hydraulic drive line 71 includes a pipe 711, a valve 712, a flow path 713, a hydraulic piston 714, a spring 715, and a throttle valve 75. The flow passage 713 is formed in the exhaust valve hydraulic cylinder 253. The hydraulic piston 714, the spring 715, and the throttle valve 75 are housed inside the exhaust valve hydraulic cylinder 253. A monitoring system 76 that monitors the first hydraulic drive line 71 is provided near the throttle valve 75.

The pipe 711 guides the drive oil sent from the drive oil pump 74 (see fig. 1) to the flow path 713. In fig. 2, the driving oil flowing through the flow path 713 and the like are also indicated by parallel oblique lines. The valve 712 is provided in the pipe 711, and controls supply of the drive oil to the flow path 713. By opening and closing the valve 712, the state of the drive oil of the first hydraulic drive line 71 is switched between the pressure-increasing state and the non-pressure-increasing state. In fig. 2, the first hydraulic drive line 71 is shown when not boosting.

The flow passage 713 is connected to an upper end portion of the hydraulic piston 714 and a lower end portion of the throttle valve 75. The hydraulic piston 714 is a substantially covered cylindrical member. A spring 715 is housed inside the hydraulic piston 714. The lower end of the spring 715 contacts the upper end surface of the valve rod 252 of the exhaust valve 25. The valve rod 252 is pressed against the spring 715 (i.e., upward) by an air piston 254 provided in an exhaust valve cylinder 253. The spring 715 is, for example, a coil spring. The spring 715 may be a variety of elastic members other than coil springs.

In the first hydraulic drive line 71 at the time of non-pressure increase, the valve rod 252, the hydraulic piston 714, and the spring 715 are pressed upward by the pressure of the air piston 254. The upper end of the hydraulic piston 714 is in contact with or in close proximity to the top cover of the exhaust valve hydraulic cylinder 253, and the exhaust valve 25 is closed. On the other hand, in the first hydraulic drive line 71 at the time of boosting, the spring 715 is pressed downward by the pressure of the boosted drive oil. Thereby, the spring 715 and the valve rod 252 move downward against the pressure of the air piston 254, and the exhaust valve 25 is opened. In the first hydraulic drive line 71, when the pressure boosting of the drive oil is completed and the drive oil returns to the non-boosted state, the valve rod 252 and the spring 715 are pushed up by the pressure of the air piston 254, and the exhaust valve 25 is closed.

The drive oil in the exhaust valve hydraulic cylinder 253 flows out from a plurality of orifices provided in the side wall of the exhaust valve hydraulic cylinder 253, is received in a drive oil reservoir 255 provided below the air piston 254, and is temporarily stored. The drive oil stored in the drive oil reservoir 255 flows down along the outer side surface of the valve rod 252 from the gap between the drive oil reservoir 255 and the valve rod 252. Thereby, frictional resistance is reduced in the sliding portion of the exhaust valve 25 (for example, a portion 257 between the support portion that supports the valve rod 252 and the valve rod 252), and the movement of the exhaust valve 25 in the up-down direction is smoothly performed. In addition, the sliding portion is hermetically sealed.

The drive oil flowing down from the drive oil reservoir 255 is temporarily stored as drain oil in a crankcase (not shown) located below the cylinder 2. The drain oil is pumped up by the circulation pump, purified by a filter or the like, and returned to the drive oil tank 73 to be reused. In the following description, a flow path of the drive oil from the exhaust valve hydraulic cylinder 253 to the crankcase is referred to as a "drain line".

The throttle valve 75 is a mechanical valve that exhausts the drive oil in the first hydraulic drive line 71. The throttle valve 75 is disposed above, for example, the hydraulic piston 714 in the first hydraulic drive line 71. The upper end portion of the throttle valve 75 is disposed inside a buffer 716 formed in the exhaust valve hydraulic cylinder 253. The buffer 716 is a relatively small space for temporarily storing the drive oil flowing out of the flow path 713 via the throttle valve 75.

Fig. 3 and 4 are enlarged cross-sectional views showing the throttle valve 75. Fig. 3 shows the throttle valve 75 in an open state when the first hydraulic drive line 71 is not pressurized. Fig. 4 shows the throttle valve 75 in a closed state when the first hydraulic drive line 71 is pressurized. The throttle valve 75 is a substantially cylindrical member centered on the center axis J1. In the example shown in fig. 3, the central axis J1 is oriented in a substantially vertical direction. The length of the throttle valve 75 in the up-down direction is, for example, 4.3cm to 5.5cm.

The throttle valve 75 includes an outer cylinder 751, an inner cylinder 752, and an elastic member 753. The outer tube 751 and the inner tube 752 are substantially cylindrical members extending in a substantially vertical direction about the central axis J1. The outer tube 751 has a lower opening 754 and an upper opening 755 at a lower end and an upper end, respectively. The inner cylinder 752 is disposed inside the outer cylinder 751 between the lower opening 754 and the upper opening 755. The inner cylinder 752 is movable in the up-down direction between the position shown in fig. 3 and the position shown in fig. 4. The elastic member 753 is disposed between the outer surface of the inner tube portion 752 and the inner surface of the outer tube portion 751 in a state compressed in the up-down direction. The elastic member 753 presses the inner cylinder 752 downward. In the example shown in fig. 3 and 4, the elastic member 753 is a coil spring.

A plurality of orifices 756 penetrating the inner tube 752 are provided on the upper side surface of the inner tube 752. In the throttle valve 75, the internal space of the inner cylinder 752 and the internal space of the outer cylinder 751 communicate with each other through a plurality of orifices 756. In the example shown in fig. 3 and 4, four orifices 756 are arranged at substantially equiangular intervals in the circumferential direction about the central axis J1. The number and arrangement of orifices 756 can be suitably varied.

In the first hydraulic drive line 71 at the time of non-pressure increase shown in fig. 3, the drive oil in the flow path 713 (see fig. 2) flows into the throttle valve 75 through the lower opening 754, and flows upward in the inner space of the inner cylinder 752. The drive oil flows out from the inner space of the inner cylinder 752 to a space between the upper outer surface of the inner cylinder 752 and the inner surface of the outer cylinder 751 through the plurality of orifices 756, and flows out to the outside of the throttle valve 75 through the upper opening 755. The gas in the drive oil of the first oil pressure drive line 71 is discharged to the outside of the first oil pressure drive line 71 together with the drive oil flowing out to the outside from the throttle valve 75. In the throttle valve 75, the lower opening 754 is an inlet of the drive oil, and the upper opening 755 is an outlet of the drive oil. In the following description, the lower opening 754 and the upper opening 755 of the throttle valve 75 are referred to as "inlet 754" and "outlet 755", respectively.

On the other hand, in the first hydraulic drive line 71 at the time of boosting shown in fig. 4, the boosted drive oil pressure is received, and the inner cylinder 752 is pressed upward. Thereby, the inner cylinder 752 moves upward while compressing the elastic member 753, and the outer surface of the upper end portion of the inner cylinder 752 contacts the inner surface of the outer cylinder 751. As a result, the outlet 755 is closed by the inner cylinder 752, and the outflow of the drive oil from the throttle valve 75 is stopped. In the throttle valve 75, when the pressure boosting of the drive oil is completed and the state returns to the non-boosted state, the inner cylinder 752 is pushed down by the restoring force of the elastic member 753, and the outlet 755 is opened.

As shown in fig. 2, the monitoring system 76 includes the throttle valve 75, a sensor portion 761, a monitoring portion 762, and an outflow line 769. The sensor portion 761 includes a mounting portion 764 and a pressure sensor 765. The attachment portion 764 is attached to the outer wall of the exhaust valve hydraulic cylinder 253 laterally of the buffer portion 716. A flow path through which the drive oil flowing out from the buffer 716 to the outside of the exhaust valve cylinder 253 flows is formed inside the attachment portion 764. The pressure sensor 765 is disposed below the flow path of the mounting portion 764, and measures the pressure of the drive oil flowing through the flow path (i.e., the pressure of the drive oil flowing out of the outlet 755 of the throttle valve 75) at the lower portion of the flow path. The pressure sensor 765 is preferably disposed at a lower side than the outlet 755 of the throttle valve 75.

The flow path inside the attachment portion 764 is connected to one end of the outflow pipe 769. The outflow line 769 is a pipe extending upward and downward outside the exhaust valve hydraulic cylinder 253 to a position above the outlet 755 of the throttle valve 75. The other end of the outflow line 769 is connected to the exhaust valve hydraulic cylinder 253, and communicates with the internal space of the exhaust valve hydraulic cylinder 253 above the drive oil reservoir 255. The outflow line 769 may be provided inside the exhaust valve hydraulic cylinder 253.

The outflow line 769 returns the drive oil flowing out from the buffer 716 to the outside of the exhaust valve cylinder 253 to the inside of the exhaust valve cylinder 253. The drive oil introduced into the exhaust valve hydraulic cylinder 253 through the outflow line 769 is received by the drive oil reservoir 255 and stored temporarily. As described above, the drive oil stored in the drive oil reservoir 255 flows down along the outer surface of the valve rod 252 from the gap between the drive oil reservoir 255 and the valve rod 252. Thereby, frictional resistance is reduced in the sliding portion of the exhaust valve 25, and the movement of the exhaust valve 25 in the up-down direction is smoothly performed. In addition, the sliding portion is hermetically sealed.

When the flow path inside the buffer portion 716, the mounting portion 764, and the outflow pipe 769 are collectively referred to as the "guide flow path 760", the guide flow path 760 is a flow path for guiding the driving oil flowing out from the outlet 755 of the throttle valve 75 to the sliding portion of the exhaust valve 25. As described above, the drive oil guided to the sliding portion is used as the friction-reducing lubricating oil. The discharge passage 760 does not necessarily need to guide all the drive oil flowing out from the throttle valve 75 to the sliding portion of the exhaust valve 25. The discharge flow passage 760 is preferably a sliding portion that guides at least a part of the drive oil flowing out from the throttle valve 75 to the exhaust valve 25. The discharge passage 760 is provided independently of the drain line through which the drive oil discharged from a portion other than the throttle valve 75 of the first hydraulic drive line 71 flows.

As described above, the pressure sensor 765 illustrated in fig. 2 is attached to the flow path inside the attachment portion 764, but the pressure sensor 765 may be attached to any portion of the lead-out flow path 760. For example, a pressure sensor 765 may be mounted to the buffer 716 to measure the pressure of the drive oil in the buffer 716. Alternatively, a pressure sensor 765 may be mounted to the outflow line 769 to determine the pressure of the drive oil in the outflow line 769. That is, the pressure sensor 765 measures the pressure of the drive oil flowing out from the outlet 755 of the throttle valve 75 in the discharge flow path 760. The output from the pressure sensor 765 (i.e., a measured value of the pressure of the drive oil) is sent to the monitoring unit 762.

Fig. 5 is a diagram showing an example of the pressure of the drive oil flowing out from the throttle valve 75 to the delivery flow path 760. Fig. 5 shows an output from the pressure sensor 765 in a case where the gas content rate of the drive oil supplied from the first hydraulic drive line 71 to the exhaust valve 25 is within a normal range (hereinafter, also referred to as "normal state"). In the following description, the periodic variation in the pressure of the drive oil flowing out from the outlet 755 of the throttle valve 75 in the normal state is referred to as "reference variation".

The normal state is a state in which the ratio of the gas contained in the drive oil supplied to the exhaust valve 25 to the drive oil is equal to or less than a predetermined threshold value. In other words, the normal state is a state in which the ratio of the space occupied by the gas in the internal space of the first hydraulic drive line 71 (i.e., the gas occupancy) is equal to or less than a predetermined threshold. Further, in the normal state, the operation of the exhaust valve 25 is also normal.

In the following description, a state in which the gas content is greater than the normal range is also referred to as an "abnormal state". The cause of the abnormal state is, for example: a large amount of air is mixed into the drive oil supplied to the exhaust valve 25, or the amount of oil in the first hydraulic drive line 71 is insufficient due to a shortage of the drive oil in the drive oil tank 73, or the like. Even in the abnormal state, the operation of the exhaust valve 25 is not necessarily abnormal. For example, even when the gas content of the drive oil supplied to the exhaust valve 25 is slightly larger than the normal range, the operation of the exhaust valve 25 is not abnormal while being maintained in a state close to the normal range. On the other hand, if the gas content of the drive oil supplied to the exhaust valve 25 continues to increase beyond the normal range, the exhaust valve 25 may shift from the normal operation to the abnormal operation.

As described above, since the throttle valve 75 is a valve that performs the exhaust of the drive oil in the first hydraulic drive line 71, the gas content of the drive oil flowing out from the outlet 755 of the throttle valve 75 is greater than the gas content of the drive oil supplied to the exhaust valve 25. Further, when the gas content of the driving oil supplied to the exhaust valve 25 increases, the gas content of the driving oil flowing out from the outlet 755 of the throttle valve 75 also increases. Further, the pressure of the driving oil flowing out from the outlet 755 of the throttle valve 75 is much smaller than the pressure of the driving oil supplied to the exhaust valve 25. For example, the pressure of the driving oil flowing out from the throttle valve 75 is about one tenth of the pressure of the driving oil supplied to the exhaust valve 25.

The horizontal axis in fig. 5 represents the crank angle (°) of the crank mechanism connected to the piston 3. The vertical axis in fig. 5 represents the pressure (bar) of the drive oil flowing out from the outlet 755 of the throttle valve 75. The curve labeled 90 in fig. 5 is a baseline variation in the pressure of the drive oil over a period (i.e., during a crank angle change from 0 ° to 360 °). In the crank angle range of 0 ° to about 120 °, the first hydraulic drive line 71 is in a non-pressure-increasing state, and the drive oil flows out from the outlet 755 of the throttle valve 75 in an open state. Therefore, the pressure of the drive oil measured by the pressure sensor 765 is substantially the same as the pressure of the drive oil at the time of non-pressure increase and is relatively low.

When the crank angle becomes about 120 °, the first hydraulic drive line 71 is in a pressure-increasing state, and the throttle valve 75 is shifted from an open state to a closed state. At this time, the pressurized driving oil flows out from the outlet 755 of the throttle valve 75 in a short time before the throttle valve 75 is in the closed state. Therefore, when the crank angle is about 120 °, the pressure of the drive oil measured by the pressure sensor 765 instantaneously increases, and a peak of the pressure occurs in the reference fluctuation.

In the crank angle range of about 120 ° to about 240 °, the first hydraulic drive line 71 is in a pressure-increasing state, and the throttle valve 75 is in a closed state, so the pressure of the drive oil measured by the pressure sensor 765 is relatively low. In addition, in the crank angle range of about 240 ° to 360 °, the first hydraulic drive line 71 is in a non-pressure-increasing state, and the throttle valve 75 is in an open state, so the pressure of the drive oil measured by the pressure sensor 765 is relatively low. The pressure fluctuation of the drive oil in the crank angle range of about 300 ° to 360 ° is caused by the supply of the drive oil by the drive oil supply portion 77 or the like, not by the opening and closing of the throttle valve 75.

The reference fluctuation shown in fig. 5 is obtained by measuring the pressure of the drive oil by the pressure sensor 765 in a state where it is confirmed that the gas content of the drive oil supplied to the exhaust valve 25 is within a normal range, for example. Alternatively, the reference fluctuation may be obtained by simulation or the like.

The monitor 762 shown in fig. 2 is, for example, a general-purpose computer. The computer includes a processor 81, a memory 82, an input/output unit 83, and a bus 84, as shown in fig. 6. The bus 84 is a signal circuit that connects the processor 81, the memory 82, and the input/output unit 83. The memory 82 stores programs and various information. The processor 81 executes various processes (for example, numerical calculation or image processing) while using the memory 82 or the like according to a program or the like stored in the memory 82. The input/output unit 83 includes a keyboard 85 and a mouse 86 for receiving input from an operator, and a display 87 for displaying output from the processor 81.

As shown in fig. 2, the monitoring unit 762 includes a storage unit 766, a detection unit 767, and an alarm unit 768. The storage 766 is mainly implemented by the memory 82, and stores various information. The detection unit 767 is mainly implemented by the processor 81, and detects an abnormality in the gas content rate in the first hydraulic drive line 71 based on the information stored in the storage unit 766 and the output from the pressure sensor 765 (i.e., the measured value of the pressure sensor 765). The alarm unit 768 gives an alarm to a crew member or the like when detecting that the gas content is abnormal. The alarm generated by the alarm unit 768 is, for example, a warning displayed on the display 87, an alarm buzzer sound, or the like.

Specifically, the storage portion 766 stores a reference variation in the pressure of the drive oil flowing out from the outlet 755 of the throttle valve 75. The storage 766 may store the entire reference fluctuation or a part of the value of the reference fluctuation. In the present embodiment, the peak pressure at the crank angle of about 120 ° in the reference fluctuation (i.e., the maximum value of the reference fluctuation) is stored in advance as the reference value in the normal state.

In the first hydraulic drive line 71, when the gas content of the drive oil supplied to the exhaust valve 25 is greater than the normal range, the gas content of the drive oil flowing out from the outlet of the throttle valve 75 to the discharge flow path 760 also increases. Therefore, the apparent volume spring rate of the drive oil flowing through the discharge flow path 760 decreases, and as shown in fig. 7 and 8, the pressure pulsation of the drive oil flowing out from the throttle valve 75 to the discharge flow path 760 also decreases. The curves labeled 91 and 92 in fig. 7 and 8 show the periodic variation in the pressure of the drive oil flowing out from the throttle valve 75 to the discharge flow path 760 in the abnormal state. Fig. 7 and 8 show the reference fluctuation shown in fig. 5 in a broken line. The state shown in fig. 8 has a higher gas content of the drive oil than the state shown in fig. 7. In the state of fig. 7, the operation of the exhaust valve 25 is not abnormal, but in the state of fig. 8, the operation of the exhaust valve 25 is abnormal.

The detection unit 767 compares the measured value of the pressure sensor 765 with the normal reference value stored in the storage unit 766 for the peak pressure at the crank angle of about 120 ° (i.e., the peak pressure of the drive oil immediately before the closing of the outlet 755 of the throttle valve 75). Then, when the difference between the reference value and the measured value of the pressure sensor 765 is greater than the predetermined threshold value, it is determined that an abnormality in the gas content rate in the first hydraulic drive line 71 (that is, an abnormality in which the gas content rate becomes greater than the normal range) has occurred. When the gas content abnormality is detected by the detection unit 767, the warning unit 768 notifies the crew member of the gas content abnormality.

The pressure sensor 765 may continuously measure the pressure of the drive oil in the discharge flow path 760, or may intermittently measure the pressure of the drive oil in the discharge flow path 760 at predetermined times. For example, in the case of detecting an abnormality in the gas content based on the peak pressure at a crank angle of about 120 ° as described above, the pressure sensor 765 may measure only the pressure of the drive oil at a crank angle of about 120 °. In this case, the pressure measurement by the pressure sensor 765 is preferably performed based on a drive control signal for the exhaust valve 25 issued in synchronization with the crank angle.

In the detection unit 767, the value of the gas content rate of the drive oil in the first hydraulic drive line 71 may be acquired based on the measured value of the pressure sensor 765. For example, a table or a formula or the like showing a relation between the peak pressure of the drive oil flowing out from the outlet 755 of the throttle valve 75 and the gas content of the drive oil in the first hydraulic drive line 71 is stored in advance in the storage unit 766, and the gas content of the drive oil in the first hydraulic drive line 71 is obtained based on the measured value of the pressure sensor 765 and the table or the formula or the like. In the detection unit 767, the gas content of the drive oil in the first hydraulic drive line 71 may be obtained based on a difference between the measured value of the pressure sensor 765 and the normal-state reference value stored in the storage unit 766.

In the case where the gas content rate is obtained in the above-described manner, the alarm unit 768 may issue an alarm when the gas content rate of the drive oil in the first hydraulic drive line 71 obtained by the detection unit 767 is greater than a predetermined threshold value. For example, the alarm unit 768 issues a first alarm at a stage when the detection unit 767 detects an abnormality in the gas content rate, and issues a second alarm at a stage when the gas content rate acquired by the detection unit 767 increases to a level near the level at which an abnormality in the operation of the exhaust valve 25 is caused (i.e., a stage when the gas content rate becomes greater than the threshold value).

The detection unit 767 may detect the abnormality of the gas content rate in the first hydraulic drive line 71 not necessarily when the difference between the reference value in the normal state and the measured value of the pressure sensor 765 is greater than a predetermined threshold value, but may detect the abnormality of the gas content rate in the first hydraulic drive line 71 when the difference between the reference value in the normal state and the measured value of the pressure sensor 765 is greater than a predetermined threshold value and the measured value of the pressure sensor 765 continuously decreases in a plurality of cycles. This prevents the sudden and immediate return to normal gas mixture from being detected as an abnormality in the gas content rate, and thus enables accurate detection of a serious abnormality such as a gradual increase in the gas content rate in the first hydraulic drive line 71. The detection of the abnormality in the gas content by the detection unit 767 is not limited to the case where the measured value of the peak pressure continuously decreases in a plurality of cycles, and may be all detected as the abnormality in the gas content when the peak pressure is less than or equal to the reference value by a certain degree or more.

As described above, the monitoring system 76 monitors the oil pressure drive line (i.e., the first oil pressure drive line 71) of the diesel engine 1. The monitoring system 76 includes a throttle valve 75, a discharge flow path 760, a pressure sensor 765, and a detection unit 767. The throttle valve 75 has an inlet 754 and an outlet 755 for drive oil from the first hydraulic drive line 71. The throttle valve 75 is pressurized by the pressure of the drive oil to close the outlet 755 when the drive oil is pressurized, and opens the outlet 755 when the drive oil is not pressurized, so as to perform the exhaustion of the first hydraulic drive line 71. The discharge flow passage 760 guides the drive oil flowing out from the outlet 755 of the throttle valve 75. The pressure sensor 765 measures the pressure of the drive oil flowing out from the outlet 755 in the discharge flow path 760. The detection unit 767 detects an abnormality in the gas content rate in the first hydraulic drive line 71 based on the measurement value of the pressure sensor 765.

As described above, since the throttle valve 75 is a valve that performs the exhaust of the drive oil in the first hydraulic drive line 71, the gas content of the drive oil flowing out from the outlet 755 of the throttle valve 75 is greater than the gas content of the drive oil supplied to the drive target (i.e., the exhaust valve 25) in the first hydraulic drive line 71. The pressure of the driving oil flowing out of the throttle valve 75 is smaller than the pressure of the driving oil supplied to the driving target. Therefore, when the gas content in the drive oil supplied to the drive target is shifted from the normal state to the abnormal state, the apparent volume spring rate of the drive oil flowing out of the throttle valve 75 is reduced to a greater extent than the drive oil supplied to the drive target, and the amplitude of the pressure fluctuation is also reduced to a greater extent. In other words, the influence of the gas contained in the drive oil is greater on the drive oil flowing out from the throttle valve 75 than on the drive oil supplied to the drive target.

Therefore, as described above, by measuring the pressure of the drive oil flowing out from the outlet 755 of the throttle valve 75, early detection of abnormality in the gas content rate in the first hydraulic drive line 71 can be achieved. In the diesel engine 1, if the abnormality of the gas content in the first hydraulic drive line 71 can be detected before the occurrence of the abnormality of the operation of the drive target of the first hydraulic drive line 71, the abnormality of the operation of the drive target can be prevented in advance. As a result, malfunction of the diesel engine 1 can be prevented.

As described above, the driving target of the first hydraulic drive line 71 preferably includes the exhaust valve 25 of the diesel engine 1. This can prevent or suppress abnormal operation of the exhaust valve 25, which plays an important role in driving the diesel engine 1.

As described above, the detection unit 767 preferably detects an abnormality in the gas content rate in the first hydraulic drive line 71 by comparing the measured value of the pressure sensor 765 with the reference value in the normal state for the peak pressure of the drive oil immediately before the outlet 755 of the throttle valve 75 is closed. This increases the difference between the pressure measurement value of the drive oil in the normal state and the pressure measurement value of the drive oil in the abnormal state, and thus enables accurate detection of abnormality in the gas content rate in the first hydraulic drive line 71.

Further, it is preferable that the detection unit 767 detects that the gas content rate in the oil pressure drive line is abnormal when the peak pressure continuously decreases in a plurality of cycles. As a result, a decrease in the single peak pressure (i.e., noise) due to sudden gas mixing is not detected as a gas content abnormality, and a significant gas content abnormality such as a gradual increase in the gas content in the first hydraulic drive line 71 can be accurately detected.

As described above, the measurement by the pressure sensor 765 is preferably performed based on the drive control signal for the drive target of the first hydraulic drive line 71. As a result, the pressure at a predetermined time (for example, the peak pressure of the drive oil immediately before the outlet 755 of the throttle valve 75 is closed) can be easily obtained in the periodic variation of the pressure of the drive oil in the discharge flow path 760.

As described above, the discharge flow path 760 is preferably provided independently of a drain line through which the drive oil discharged from a portion other than the throttle valve 75 of the first hydraulic drive line 71 flows. This can prevent or reduce the influence of the pressure fluctuation of the drive oil flowing out from the throttle valve 75, and can accurately measure the pressure of the drive oil flowing out from the throttle valve 75. As a result, the abnormality of the gas content in the first hydraulic drive line 71 can be accurately detected.

As described above, the detection unit 767 preferably obtains the gas content rate in the first hydraulic drive line 71 based on the measurement value of the pressure sensor 765. Thus, the degree of abnormality (i.e., whether it is a slight abnormality or a serious abnormality) of the gas content rate in the first hydraulic drive line 71 can be grasped. As a result, appropriate measures such as maintenance can be selected in accordance with the degree of abnormality in the gas content.

Further, the monitoring system 76 preferably further includes an alarm unit 768, and the alarm unit 768 issues an alarm when the gas content rate in the first hydraulic drive line 71 acquired by the detection unit 767 is greater than a predetermined threshold value. Therefore, the crew and the like can recognize, at an early stage, a significant gas content abnormality that has a high possibility of causing an abnormal operation of the driving target of the first hydraulic drive line 71.

Various modifications may be made in the monitoring system 76.

For example, in the detection unit 767, the measured value is compared with the reference value for the peak pressure of the drive oil immediately before the outlet 755 of the throttle valve 75 is closed, but the abnormality of the gas content in the first hydraulic drive line 71 may be detected by comparing the measured value with the reference value for the pressure of the other part in the pressure fluctuation (for example, the peak pressure when the crank angle is about 340 °).

The pressure measurement of the drive oil by the pressure sensor 765 is not necessarily performed based on the drive control signal for the drive target (i.e., the exhaust valve 25) of the first hydraulic drive line 71, and may be performed continuously and constantly, for example.

In the monitoring system 76, the outflow line 769, which is independent of the drain line, may also be omitted, and the drive oil flowing out from the outlet 755 of the throttle valve 75 may be led directly to the drain line. The drive oil flowing out from the throttle valve 75 of the first hydraulic drive line 71 is not necessarily guided to the sliding portion of the exhaust valve 25, and is used as lubricating oil.

In the detection unit 767, the gas content in the first hydraulic drive line 71 is not necessarily obtained. The alarm unit 768 may not be based on the gas content, and may always issue an alarm when detecting that the gas content is abnormal. Further, the alarm 768 is not necessarily provided.

The throttle valve 75 is not limited to the above-described structure, and may have other various structures. For example, a so-called check valve may also be used as the throttle valve 75.

The hydraulic drive line monitored by the monitoring system 76 is not necessarily the first hydraulic drive line 71 for the exhaust valve 25, but may be a hydraulic drive line for driving another driving object. For example, the second oil pressure drive line 72 for driving the fuel supply pump 62 may be monitored by the monitoring system 76.

The diesel engine 1 provided with the monitoring system 76 is not limited to a two-stroke engine, but may be a four-stroke engine. The monitoring system 76 may be provided not only in a diesel engine that serves as a main engine of a ship but also in various diesel engines such as a diesel engine for power generation and a diesel engine for an automobile.

The above-described embodiments and the configurations of the respective modifications may be appropriately combined as long as they do not contradict each other.

The invention has been depicted and described in detail, but the description is illustrative and not restrictive. Accordingly, the present invention can be modified in various forms without departing from the scope of the present invention.

Claims

1. A monitoring system for monitoring an oil pressure drive line of a diesel engine, the monitoring system comprising:

a throttle valve having an inlet and an outlet for driving oil from a hydraulic driving line, wherein the throttle valve is closed by receiving pressure of the driving oil when the driving oil is pressurized, and is opened to exhaust the hydraulic driving line when the driving oil is not pressurized;

a discharge flow path for guiding the drive oil flowing out from the outlet of the throttle valve;

a pressure sensor that measures a pressure of the driving oil flowing out from the outlet in the lead-out flow path; and

and a detection unit configured to detect an abnormality in the gas content in the hydraulic drive line based on the measurement value of the pressure sensor.

2. The monitoring system of claim 1, wherein,

the detection unit detects an abnormality in the gas content in the hydraulic drive line by comparing a measured value of the pressure sensor with a reference value in a normal state for a peak pressure of the drive oil immediately before the outlet of the throttle valve is closed.

3. The monitoring system of claim 2, wherein,

the detection unit detects that the gas content rate in the hydraulic drive line is abnormal when the peak pressure continuously decreases in a plurality of cycles.

4. The monitoring system of claim 1, wherein,

the measurement by the pressure sensor is performed based on a drive control signal for a drive target of the hydraulic drive line.

5. The monitoring system of claim 1, wherein,

the delivery passage is provided independently of a drain line through which the drive oil discharged from a portion other than the throttle valve of the hydraulic drive line flows.

6. The monitoring system of claim 1, wherein,

the detection unit obtains the gas content in the hydraulic drive line based on the measured value of the pressure sensor.

7. The monitoring system of claim 6, wherein,

the hydraulic drive system further includes an alarm unit that generates an alarm when the gas content in the hydraulic drive line acquired by the detection unit is greater than a predetermined threshold value.

8. The monitoring system according to any one of claims 1 to 7, wherein,

the drive target of the oil pressure drive line includes an exhaust valve of a diesel engine.