KR20130086050A - Gas fuel leakage detection method, and gas fuel leakage detection device, and gas engine equipped with same - Google Patents

Abstract

The gaseous fuel leak detection method applied to the gas engine 10 uses the pressure of the fuel supply pipe 29 for supplying gaseous fuel from the fuel header 25 to the fuel supply valve 26 to close the valve of the fuel supply valve 26. It detects within a period and determines whether gaseous fuel is leaking based on the detected pressure. Another method detects the oxygen concentration in the air supply port 13 to which gaseous fuel is supplied from the fuel supply valve 26, and determines whether gaseous fuel is leaking based on the detected oxygen concentration. Another method detects the vibration intensity according to the opening and closing of the fuel supply valve 26 using the vibration sensor provided in the fuel supply valve 26, and determines whether gaseous fuel is leaking based on the detected vibration intensity. .

Description

GAS FUEL LEAKAGE DETECTION METHOD, AND GAS FUEL LEAKAGE DETECTION DEVICE, AND GAS ENGINE EQUIPPED WITH SAME}

The present invention relates to a method and apparatus for detecting leakage of gaseous fuel from a fuel supply valve for a gas engine, and a gas engine having the apparatus.

The fuel supply system of the gas engine includes a fuel header and a plurality of fuel supply pipes. The fuel header is provided in common in a plurality of cylinders and receives gaseous fuel from a fuel supply source. The fuel supply pipe is provided for each cylinder and connects a fuel header to a corresponding fuel supply valve. The fuel supply valve injects gaseous fuel supplied from the fuel supply pipe for each engine cycle. When the fuel supply valve is arranged in the air supply port, the injected gaseous fuel is supplied to the combustion chamber together with the air supply in the air supply stroke. In a gas engine, the volume of gaseous fuel injected for every engine cycle is large compared with that in the engine using liquid fuel, such as gasoline. For this reason, the fuel supply valve for gas engines opens or closes a injection hole largely by the minute movement of a valve body.

Undesirably, there are cases where foreign matter is caught between the valve body of the fuel supply valve and the valve seat so that the valve body cannot properly contact the valve seat.

If foreign matter is caught in the fuel injection valve for the gas engine, the injection port may be greatly opened, and a large amount of gaseous fuel may leak. When the gaseous fuel leaks, the air-fuel ratio in the combustion chamber becomes over rich, and misfire is likely to occur, and the unburned gas in the exhaust is large, and after fire easily occurs. For this reason, the fuel supply valve cannot be closed properly due to the contamination of foreign matters, and when the gaseous fuel leaks by this, it is quickly detected, and prompt and appropriate measures such as emergency stop of the engine are required.

Therefore, conventionally, the apparatus and method for detecting the leakage of gaseous fuel are proposed (for example, refer patent documents 1-3). Although different from a fuel supply valve, the apparatus and the method for detecting whether the foreign matter is stuck in the intake / exhaust valve are also proposed (for example, refer patent document 4). On the other hand, the apparatuses and methods disclosed in Patent Documents 1 to 4 are all intended for application to a vehicle engine.

Patent document 1 is disclosing the opening failure detection apparatus provided with the shutoff valve and the pressure sensor. The shutoff valve is installed in a passage for supplying gaseous fuel to the fuel supply valve, and the pressure sensor detects the pressure between the fuel supply valve and the shutoff valve. This apparatus monitors the pressure between the two valves in a state where the fuel supply valve and the shutoff valve are closed with a valve, and determines that gaseous fuel is leaking when the pressure decreases.

Patent document 2 is disclosing the fuel leak detection apparatus provided with the pressure sensor. The pressure sensor detects the pressure of the fuel supply passage upstream of the fuel supply valve. This apparatus judges that gaseous fuel is leaking when the pressure after a predetermined period since the start of the fuel cut is lower than the predetermined value. On the other hand, fuel cut is performed when the vehicle is decelerating. During fuel cut execution, the fuel supply valve stops with the injection port closed.

Patent document 3 is disclosing the fuel injection apparatus provided with the oxygen concentration sensor which detects the oxygen concentration of exhaust. This apparatus gives a valve opening command to a fuel supply valve so that the actual air excess rate obtained from the oxygen concentration of exhaust may correspond to the target air excess rate according to an operating condition. And comparing the current valve opening command given to the fuel supply valve with the valve opening command in the initial state of use previously given to the fuel supply valve under the same operating conditions. When the difference in the valve open command becomes large, it is determined that gaseous fuel is leaking.

Patent document 4 is disclosing the foreign material pinch detection apparatus using a knock sensor. The knock sensor is installed in the cylinder block to detect vibration of the engine. This device selects the valve closing vibration of the intake and exhaust valve by passing the engine vibration through a band pass filter, and when the timing of occurrence of the valve closing vibration deviates four times consecutively from the expectation, the foreign matter enters the intake and exhaust valve. I think it is stuck.

Japanese Patent Laid-Open No. 2006-250141 Japanese Patent Application Laid-Open No. 2001-032751 Japanese Patent Application Laid-Open No. 2002-332878 Japanese Patent Application Laid-Open No. 2000-240479

However, according to the method disclosed in Patent Literature 1, whether or not the gaseous fuel is leaking under a situation in which it is allowed to monitor the time change in pressure while the shutoff valve is closed, that is, under the condition that the engine is stopped. I can't judge. For this reason, even if gaseous fuel leaks while the engine is running, it cannot be detected quickly.

According to the method disclosed in Patent Literature 2, it is not possible to determine whether or not gaseous fuel is leaking, unless under the condition of performing fuel cut. For this reason, even if gaseous fuel leaks while the fuel supply valve is operating normally, this cannot be detected quickly. Like the engine for power generation, it is very difficult to cope with the leakage of gaseous fuel quickly even if this method is adopted in a use or field where the opportunity to perform fuel cut is less than that of a vehicle engine.

According to the method disclosed in Patent Document 3, the leakage of the gaseous fuel cannot be detected until the leakage of the gaseous fuel affects the oxygen concentration of the exhaust gas. For this reason, it is difficult to cope quickly with leakage of gaseous fuel. In addition, it is not possible to specify which cylinder the abnormal fuel supply valve corresponds to.

According to the method disclosed in Patent Document 4, even if jamming of foreign matter occurs, it cannot be detected unless at least four engine cycles have elapsed thereafter. Therefore, it is difficult to respond quickly to the jamming of foreign objects.

Moreover, it is not easy to use the method disclosed by patent document 4 for a fuel supply valve. The valve closing vibration of the fuel supply valve is small compared to the intake and exhaust valve, and the fuel supply valve is disposed distal from the cylinder block in comparison with the intake and exhaust valve. For this reason, it is very difficult to sort out the valve closing vibration of the fuel supply valve from the vibration of the engine detected by the knock sensor. In addition, the fuel supply valve opens and closes the injection port by a fine operation. For this reason, even if foreign matter gets caught in the fuel supply valve, the timing of generating the valve closing vibration does not greatly shift.

Therefore, an object of the present invention is to make it possible to quickly detect a gaseous fuel leak even if it is caught due to a foreign matter or the like, and thereby to cope quickly with the leakage of the gaseous fuel.

The present invention has been made to achieve the above object. In addition, below, the period in which the fuel supply valve is intended to close the valve is called "valve closing period" regardless of whether the fuel supply valve is normally closed. The period in which the fuel supply valve is intended to open the valve is referred to as "valve opening period" except when the fuel supply valve cannot normally close the valve. If not specifically mentioned before, simply describing as "a valve closing period" and a "valve opening period", it uses the fuel supply valve for gas engines.

A gaseous fuel leak detection method according to the present invention is a method for detecting a gaseous fuel leak from a fuel supply valve for a gas engine for injecting gaseous fuel, the gaseous fuel leaking from a fuel header to the fuel supply valve. A pressure is detected within the valve closing period of the fuel supply valve, and based on the detected pressure or an oxygen concentration in the air supply port receiving gas fuel from the fuel supply valve, and based on the detected oxygen concentration, Or using the vibration sensor provided in the fuel supply valve to detect the intensity of vibration caused by the opening and closing of the fuel supply valve, and determining whether gaseous fuel is leaking from the fuel supply valve based on the detected intensity of vibration. do.

According to this method, whether gaseous fuel is leaking or not is determined based on the pressure of the fuel supply pipe in the valve closing period, the oxygen concentration in the air supply port, or the vibration intensity of the fuel supply valve. Either way, when gaseous fuel leaks from the fuel injection valve for gas engines, it can be detected quickly. As a result, it is possible to quickly cope with the leakage of the gaseous fuel. The following describes how such an action occurs in accordance with the use of the method, together with the gaseous fuel leak detection apparatus according to the present invention, which has been carried out in light of the same knowledge and concept in order to achieve the same purpose.

In order to achieve the above object, the inventor has obtained the following knowledge in the process of developing a method and apparatus for detecting leakage of gaseous fuel from a fuel supply valve for a gas engine. When the fuel supply valve is normal, in the valve opening period, gaseous fuel flows at high speed in the fuel supply pipe to generate dynamic pressure. At this time, since the pressure drops due to the friction, the static pressure of the fuel supply pipe decreases. In the valve closing period, no gaseous fuel flows, and the pressure of the fuel supply pipe is approximately equal to the pressure of the gaseous fuel in the fuel header (hereinafter referred to as "soft pressure"). By the way, when the fuel supply valve cannot be normally closed due to the trapping of foreign matters, gaseous fuel continues to leak even in the valve closing period in which the fuel supply valve should be closed inherently. Then, since gaseous fuel continues to flow in the fuel supply pipe, dynamic pressure remains in the fuel supply pipe, and the static pressure does not recover to a value approximately equal to the annual pressure. The recovery failure of the static pressure occurs as soon as the leakage of the gaseous fuel occurs.

Thus, the inventors have conceived that, by using the pressure of the fuel supply pipe in the valve closing period, the leakage of gaseous fuel can be detected quickly even while the fuel supply valve is in operation (see Fig. 5). The above-described method and the first gaseous fuel leak detection apparatus according to the present invention are conceived from this knowledge and concept.

A first gaseous fuel leak detection apparatus according to the present invention is a device for detecting gaseous fuel leakage from a fuel supply valve for a gas engine, the pressure sensor detecting a pressure in a fuel supply pipe connecting a fuel header to the fuel supply valve. And a determination device that determines whether gaseous fuel is leaking from the fuel supply valve on the basis of the pressure detected by the pressure sensor within the valve closing period of the fuel supply valve.

As mentioned above, if the fuel supply valve cannot be normally closed, the recovery failure of the fuel supply line immediately occurs. And when a fuel supply valve is operated, a valve closing period exists necessarily until one engine cycle passes. Thus, in the above method and apparatus, it is determined whether gaseous fuel is leaking based on the pressure of the fuel supply pipe detected within the valve closing period. For this reason, even if the gaseous fuel leaks due to the pinch of foreign matter, it can be detected quickly and with high accuracy. Therefore, it is possible to respond quickly to the leakage of gaseous fuel.

The fuel supply pipe may have a throttle, and the pressure sensor may detect a pressure downstream from the throttle.

And a soft pressure sensor for detecting gaseous fuel pressure in the fuel header, wherein the determination device is configured to determine whether or not gaseous fuel is leaking based on a differential pressure between the pressure detected by the pressure sensor and the pressure detected by the soft pressure sensor. May be determined.

A rotational phase meter which detects the rotational phase of the crankshaft of the said gas engine may be provided, and the said determination apparatus may recognize the said valve closing period based on the rotational phase detected by the said rotational phaseometer.

The determination device may recognize the valve closing period based on the drive command signal of the fuel supply valve.

When the pressure detected by the pressure sensor in the valve closing period is lower than the pressure detected by the pressure sensor in the previous valve closing period, the determination device may determine that gaseous fuel is leaking.

The pressure detected by the pressure sensor within the valve closing period may be the pressure detected by the pressure sensor when the piston of the gas engine is located near the bottom dead center.

In addition, the inventor also obtained the following knowledge. The fuel supply valve is said to supply gaseous fuel to the air supply port. When the fuel supply valve is normal, no gaseous fuel is supplied to the supply port during the valve closing period. For this reason, the oxygen concentration in the air supply port is almost the same as the atmosphere. Even in the valve opening period, the gaseous fuel is quickly supplied to the combustion chamber together with the air supply flowing through the air supply port. For this reason, the oxygen concentration in the air supply port is almost the same as the atmosphere. As a result, when the fuel supply valve is normal, the oxygen concentration in the air supply port is stably changed within a narrow numerical range during one engine cycle. By the way, when the fuel supply valve is abnormal due to pinch of foreign matter or the like, gaseous fuel continues to leak to the air supply port even in a valve closing period in which the fuel supply valve should be closed inherently. Part or all of the valve closing period of the fuel supply valve overlaps with the period in which the air supply valve is closed. For this reason, while gaseous fuel continues to leak to an air supply port, the flow of air supply stops and oxygen concentration in an air supply port falls rapidly. In particular, when the engine speed is low, since the actual time that the air supply valve is closed between one engine cycle elapses, the decrease in the oxygen concentration in the air supply port is surfaced. This decrease in oxygen concentration in the air supply port occurs as soon as gaseous fuel leakage occurs.

Thus, the inventors have conceived that the leakage of gaseous fuel can be detected quickly by using the oxygen concentration in the air supply port (see Fig. 11). The gaseous fuel leak detection apparatus of the second embodiment according to the method and the present invention described below is conceived from this knowledge and concept.

The second gaseous fuel leak detection device according to the present invention is a device for detecting gaseous fuel leakage from a fuel supply valve for a gas engine, which detects an oxygen concentration in an air supply port receiving gaseous fuel from the fuel supply valve. And an oxygen concentration sensor and a determination device that determines whether gaseous fuel is leaking from the fuel supply valve based on the oxygen concentration detected by the oxygen concentration sensor.

As mentioned above, if the fuel supply valve is normal, the oxygen concentration in the air supply port is stably changed within a narrow numerical range during one engine cycle. On the other hand, if an abnormality occurs in the fuel supply valve, the oxygen concentration in the air supply port decreases drastically beyond the corresponding numerical range. Thus, in the above method and apparatus, it is determined whether gaseous fuel is leaking based on the oxygen concentration in the air supply port. For this reason, even if gaseous fuel leaks due to the pinch of foreign matter etc., it can be detected quickly and with high precision. This makes it possible to quickly cope with the leakage of gaseous fuel.

The determination device may compare the oxygen concentration detected by the oxygen concentration sensor with a predetermined threshold when the rotational phase of the crankshaft of the gas engine is a predetermined phase.

And a rotational phase meter for detecting the rotational phase of the crankshaft, and the determination device indirectly directs the rotational phase detected by the rotational phasemeter directly from the rotational phasemeter or through an engine control device of the gas engine. You may accept as.

When the detected oxygen concentration is lower than the predetermined threshold, the determination device may determine that gaseous fuel is leaking.

In addition, the inventor obtained the following knowledge. Vibration of the fuel supply valve occurs, for example, when the valve body contacts the valve seat or the foreign matter. When foreign matter is caught between the valve body and the valve seat, the moving distance of the valve body is shortened as compared with when no foreign matter is caught. For this reason, vibrations are alleviated by interacting with other factors. This vibration mitigation occurs as soon as the jamming of foreign matter occurs.

Therefore, the inventors of the present invention have found that, by using the intensity of vibration of the fuel supply valve, the jamming of foreign matters can be detected quickly even while the fuel supply valve is in operation, and further, the leakage of gaseous fuel can be detected quickly. (See FIG. 16). The method and the third gaseous fuel leak detection apparatus according to the present invention described below are conceived from this knowledge and concept.

A third gaseous fuel leak detection apparatus according to the present invention is a device for detecting gaseous fuel leakage from a fuel supply valve for a gas engine, and is provided in the fuel supply valve and detects a vibration intensity of the fuel supply valve. And a judging device for judging whether or not gaseous fuel is leaking from the fuel supply valve on the basis of the vibration intensity resulting from the opening and closing of the fuel supply valve detected by the vibration sensor.

As mentioned above, when the foreign matter is jammed, the intensity of vibration immediately changes. According to the above method and configuration, since the vibration sensor is provided in the fuel supply valve, the vibration intensity of the fuel supply valve is well detected. Then, it is determined whether or not gaseous fuel is leaking based on the vibration intensity resulting from the opening and closing of the fuel supply valve detected by the vibration sensor. Therefore, even if foreign matter gets caught in the fuel supply valve, it can be detected quickly and with high accuracy. Thus, even if the gaseous fuel leaks due to the trapping of foreign matters, it is possible to quickly cope with the leakage of the gaseous fuel.

An opening / closing signal supply device for supplying a signal indicating an opening / closing timing of the fuel supply valve, wherein the determination device recognizes the opening / closing of the fuel supply valve on the basis of a signal supplied from the opening / closing signal supply device, The signal supply device may be an engine control device of the gas engine, and a signal indicating opening / closing timing of the fuel supply valve may be a drive command signal of the fuel supply valve input from the engine control device.

An opening / closing signal supply device for supplying a signal indicating opening / closing timing of the fuel supply valve, wherein the determination device recognizes the opening / closing timing of the fuel supply valve based on a signal supplied from the opening / closing signal supply device, and An open / close signal supply device and a rotational phase meter for detecting the rotational phase of the crankshaft of the gas engine, and a signal indicating the open / close timing of the fuel supply valve is a rotational phase signal indicating the rotational phase of the crankshaft, The rotational phase signal may be received directly from the rotational phase meter or indirectly through an engine control device of the gas engine.

When the vibration intensity according to the opening and closing of the fuel supply valve detected by the vibration sensor is equal to or less than a predetermined threshold, the determination device may determine that gaseous fuel is leaking.

When the vibration intensity resulting from the opening and closing of the fuel supply valve detected by the vibration sensor drops to a predetermined value or more as compared with the previous one, the determination device may determine that gaseous fuel is leaking.

The gas engine according to the present invention includes the aforementioned first, second or third gaseous fuel leak detection device. According to such a gas engine, even if the gaseous fuel leaks due to the pinch of the foreign matter, it can be detected quickly and with high accuracy. Therefore, it is possible to respond quickly to the leakage of gaseous fuel.

The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of the embodiments with reference to the accompanying drawings.

As apparent from the above description, according to the present invention, even if a gaseous fuel leaks due to, for example, a foreign matter being caught, it can be detected quickly. As a result, it is possible to quickly cope with the leakage of the gaseous fuel.

1 is a conceptual diagram showing the configuration of a gaseous fuel leak detection apparatus according to a first embodiment of the present invention.
2 is a cross-sectional view conceptually illustrating a configuration of a fuel supply valve illustrated in FIG. 1.
3 is a partially cutaway front view showing a mounting position of the pressure sensor shown in FIG. 1.
4 is a graph illustrating an example of a pressure change of the fuel supply pipe illustrated in FIG. 1.
FIG. 5 is a graph for explaining the principle of gaseous fuel leak detection in the gaseous fuel leak detecting apparatus and the gaseous fuel leak detecting method according to the first embodiment shown in FIG. 1.
6 is a flowchart showing a process of the gaseous fuel leak detection method according to the first embodiment of the present invention.
7 is a conceptual diagram showing the configuration of a gaseous fuel leak detection apparatus according to a second embodiment of the present invention.
8 is a partially cutaway front view illustrating a mounting position of the oxygen concentration sensor illustrated in FIG. 7.
FIG. 9 is a graph showing the oxygen concentration in the air supply port shown in FIG. 7.
10 is a graph for explaining the principle of the gaseous fuel leak detection method according to the second embodiment of the present invention.
Fig. 11 is a graph for explaining the principle of gaseous fuel leak detection in the gaseous fuel leak detecting apparatus and the gaseous fuel leak detecting method according to the second embodiment of the present invention.
12 is a flowchart showing a process of the gaseous fuel leak detection method according to the second embodiment of the present invention.
Fig. 13 is a conceptual diagram showing the configuration of a gaseous fuel leak detection device according to a third embodiment of the present invention.
14 is a cross-sectional view conceptually illustrating a structure of the fuel supply valve illustrated in FIG. 13.
FIG. 15 is a cross-sectional view illustrating a mounting position of the vibration sensor illustrated in FIG. 13.
16 is a graph for explaining the principle of gaseous fuel leak detection in the gaseous fuel leak detection apparatus and the gaseous fuel leak detection method according to the third embodiment of the present invention.
Fig. 17 is a flowchart showing a process of the gaseous fuel leak detection method according to the third embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described, referring drawings. On the other hand, the same or corresponding elements are denoted by the same reference numerals throughout the drawings, and detailed description thereof will be omitted.

[First Embodiment]

1 is a conceptual diagram illustrating a configuration of a gaseous fuel leakage device 100 according to a first embodiment of the present invention. The gaseous fuel leakage device 100 according to the first embodiment is applied to the gas engine 10 for power generation, and the gaseous fuel is discharged from the fuel supply valve 26 according to the pressure of the fuel supply pipe 29 in the valve closing period. It is determined whether or not is leaked. Since the fuel supply valve 26 according to the present embodiment is an electromagnetic on / off valve, the engine control device controlling the operation of the electromagnetic on / off valve outputs a valve closing command signal in the "valve closing period" according to the present embodiment. It is a period of time. The "valve opening period" according to the present embodiment corresponds to a period during which the engine control device outputs a valve opening command signal. In addition, the valve closing command signal and the valve opening command signal may be collectively referred to as a drive command signal. The "valve closing period" and "valve opening period" are included in one "engine cycle" one by one when the gas engine is operating normally, and the "valve closing period" and "valve" as the engine cycle is repeated. The opening period "is repeated alternately. The engine cycle is a series of operations consisting of four strokes: an air stroke, a compression stroke, an explosion stroke, and an exhaust stroke in a four-cycle engine, and the piston reciprocates twice during one engine cycle. , Crankshaft rotates two times. "Cycle phase" is an index indicating at which time in one engine cycle, and for example, the position of the piston, the rotational phase of the crankshaft (crank angle), and the rotational phase of the rotating body linked to the crankshaft can be applied. There is a number.

The gas engine 10 which concerns on this embodiment has a some cylinder, but FIG. 1 has shown one of them. In the gas engine 10, each cylinder includes a piston 12, a connecting rod, an air supply port 13, an exhaust port 14, two air supply valves 15, two air exhaust valves 16, and a combustion chamber (main combustion chamber). (17) and the sub chamber (18), the spark plug 19, the fuel supply valve 26, the fuel supply pipe 29, and the pressure sensor 51 are provided. On the other hand, in the gas engine 10, the engine cylinder 11, the cylinder header 20, the crankshaft 21, the air supply manifold 23, and the exhaust manifold 24 are common to some or all of the some cylinder. And a fuel header 25 are provided.

The combustion chamber is surrounded by the cylinder header 20 and the side walls of the engine cylinder 11 and the piston 12. The air supply port 13 is connected to the combustion chamber via the air supply valve 15, and the air exhaust port 14 is connected to the combustion chamber through the exhaust valve 16. When the air supply valve 15 is opened to supply the air supply mixed with gaseous fuel to the combustion chamber, and after compression, the gas in the combustion chamber is expanded when the spark plug 19 is ignited, and the piston 12 is pushed in the engine cylinder 11. It lowers and the crankshaft 21 rotates through a connecting rod.

The crankshaft 21 is driven by the plurality of pistons 12 to rotate continuously. As the crankshaft 21 rotates, the exhaust valve 16 is opened while the piston 12 is pushed up through the bottom dead center so that fuel gas is discharged through the exhaust port 14. As the crankshaft 21 rotates, the generator 22 can be driven to generate electric power. The combustion chamber is comprised of the main combustion chamber 17 which the piston 12 reciprocates, and the sub chamber 18 which communicates with the main combustion chamber 17 through the opening formed in the ceiling part of the main combustion chamber 17. As shown in FIG. The sub chamber 18 is provided with a spark plug 19 and a sub fuel supply valve (not shown).

The air supply is supplied to the air supply manifold 23 through the supercharger 35. The air supply manifold 23 is connected to a plurality of air supply ports 13 and branch pipes provided for each cylinder, and distributes the uniform air supply to each cylinder. The supercharger 25 increases the density of the air supply by using the energy of the exhaust gas, and can increase the output of the gas engine 10 by increasing the density of the air supply.

The fuel supply valve 26 injects gaseous fuel into the air supply port 13, generates a mixer having a suitable air-fuel ratio, and supplies it to the combustion chamber. On the other hand, after the exhaust gas discharged to the exhaust port 14 is collected in the exhaust manifold 24 connected to the exhaust port 14 and the branch pipe, the supercharger 35, the deodorization and denitrification device 36, and the boiler ( 37) and exhausted through the exhaust gas treating apparatuses such as the silencer 38 in order to be discharged to the atmosphere. The deodorizing denitrification apparatus 36 is a device which removes a bad smell component and nitrogen oxide using an adsorption material, a catalyst, etc. In addition, a safety valve is provided in the pipe connecting each device, and when an unexpected high pressure is applied, the rupture plate is broken and the high pressure gas is discharged to the outside to prevent excessive pressure on the device.

As the gaseous fuel, for example, compressed natural gas, liquefied propane gas or compressed hydrogen can be applied. The gaseous fuel is supplied to and stored in a gaseous fuel storage device 31 such as a bombe or a tank, supplied to the regulator 33 through a shutoff valve 32, and adjusted to an appropriate pressure in the regulator 33. And then supplied to the fuel header 25 through a filter (not shown). The fuel header 25 includes a branch pipe 28 for each cylinder, and connects the fuel supply pipe 29 to the end of the branch pipe 28 through a throttle 34. If the throttle 34 is provided, there is an effect of not having a great influence on the pressure of the fuel header 25 when gas fuel flows through the air supply port 13. The lower end of the fuel supply pipe 29 is connected to the supply port of the fuel supply valve 26 to supply the gaseous fuel from the fuel header 25 to the fuel supply valve 26.

The fuel supply valve 26 is, for example, a solenoid-driven face type poppet valve. The solenoid valve capable of flowing a large amount of gas in a short time by forming a large opening with a slight stroke. to be. As conceptually shown in FIG. 2, the fuel supply valve 26 has a valve seat 46 formed of a flat plate and a valve body 45 formed of a flat plate, and the valve body 45 is in contact with the valve seat 46. In this case, the flow path in the valve through which gaseous fuel flows is blocked. The through grooves are formed concentrically in the flat plate of the valve body 45 and the flat plate of the valve seat 46, respectively, and when the valve body 45 makes planar contact with the valve seat 46, the through grooves mutually mutually. The fuel supply valve 26 is in a valve closed state by alternately meeting and blocking the passage. When the valve body 45 is separated from the valve seat 46, the plurality of through grooves are electrically conducted by a slight distance to form a large opening, and the fuel supply valve 26 is brought into the valve open state. When the valve is opened, the valve body 45 is pulled in the direction away from the valve seat 46 by the electromagnet 43, and when the valve is closed, the valve body 45 is pushed onto the valve seat 46 by the spring 44. Is attached.

In addition, a large flow rate can be secured by adjusting the gaseous fuel in the fuel header 25 to a sufficiently high pressure to adjust the differential pressure between the soft pressure and the air supply pressure to about 50 to 200 kPa. Moreover, the electromagnet 43 which pulls the valve body 45 of the fuel supply valve 26 is strong, and can pull out the valve body 45 from the valve seat 46 for a short time, and can form a large opening, Since the spring 44 which pushes the valve body 45 to the valve seat 46 is also powerful, opening and closing of the valve has a quick response of about 2 to 3 ms. On the other hand, by controlling the valve opening period of the fuel supply valve 26, the supply amount of the gaseous fuel can be set with high reproducibility. The outlet of the fuel supply valve 26 is opened to the air supply port 13. The fuel supply valve 26 injects gaseous fuel into the air supply port 13, whereby the air supply is mixed with the gaseous fuel.

The engine control device 40 individually controls the operation in the plurality of cylinders. The engine control device 40 is, for example, a rotational phase meter 41 that measures the air supply pressure signal supplied from the air supply pressure sensor 42 provided in the air supply port 13 and the rotational phase of the crankshaft 21. The situation of the gas engine 10 is grasped | ascertained by inputting the crank angle signal supplied from the fuel cell, or the pressure signal of the gaseous fuel supplied from the soft-pressure sensor 43 provided in the fuel header 25. FIG.

The engine control apparatus 40 calculates the developing output of the generator 22 based on this information, and adjusts various control variables so that the deviation may be eliminated when there is a deviation compared with the set target output. The engine control device 40 can control the air-fuel ratio in the combustion chamber by adjusting the amount of gaseous fuel supplied in the air supply using the air supply pressure. Moreover, it has a function which calculates the operation timing of the spark plug 19, the fuel supply valve 26, etc. with respect to each cylinder according to a crank angle, and gives an operation command to these cylinders. The engine control device 40 can perform an emergency stop of the engine by giving a valve closing command signal to the fuel supply valves 26 in all cylinders when necessary. In the present embodiment, since the gas engine 10 is for power generation, the engine control device 40 controls the spark plug 19, the fuel supply valve 26 and the like so that the load and the rotation speed become constant over a long period of time. .

The gaseous fuel leakage device 100 according to the present embodiment can detect gaseous fuel leakage from the fuel supply valve 26 during operation of the fuel supply valve 26. The fuel supply valve 26 switches the opening and closing with a very small stroke of less than 0.3 mm. For this reason, even if very small foreign matter penetrates, the plane of the valve body 45 and the plane of the valve seat 46 will not be able to close and close, and the valve will be closed poorly, and a large amount of gaseous fuel will leak out and supply air. It is incorporated.

If gaseous fuel leaks, the air-fuel ratio of the mixer in the combustion chamber may be over-reached to cause misfire, or unburned gas may flow into the exhaust manifold 24 to cause after-fire. If misfire occurs, the output of the generator 22 is affected. When the after-fire occurs, the life of the supercharger 35, the adsorbent and catalyst of the deodorizing and denitrification device 36, the heat exchanger of the boiler 37, and the silencer 38 is affected.

The gas engine 10 which concerns on this embodiment is equipped with the gaseous fuel leak apparatus 100 which detects and notifies immediately when a gaseous fuel leaks when the fuel supply valve 26 should close a valve. Accordingly, it is possible to transmit an abnormal signal to the engine control device 40 to take a predetermined emergency stop action, or to notify the operator to take appropriate measures such as emergency stop of the engine under high judgment. have.

The gaseous fuel leakage device 100 according to the present embodiment includes a pressure sensor 51 for detecting a pressure in the fuel supply pipe 29 for supplying gaseous fuel from the fuel header 25 to the fuel supply valve 26. Whether or not the fuel supply valve 26 is abnormal based on the pressure of the fuel supply pipe 29 detected by the pressure sensor 51 within the valve closing period of the supply valve 26 (more specifically, the fuel supply valve 26). An abnormality transmitting device 50 for determining whether or not the gaseous fuel is leaking from the gas. The pressure sensor 51 detects the pressure corresponding to the static pressure in the fuel supply pipe 29, and outputs a pressure signal. The abnormality transmitting device 50 functions as a determining device that determines whether the fuel supply valve 26 is abnormal. For determination, the abnormality transmitting device 50 inputs a pressure signal of the pressure sensor 51 and a cycle phase signal indicating a cycle phase. The cycle phase signal is output from the cycle phase signal detection device. The cycle phase detection device may be a rotational phase meter 41 or may be an electronic circuit or a computer program for determining the cycle phase in accordance with the drive command signal of the fuel supply valve 26. The abnormality transmitter 50 recognizes the valve closing period of the fuel supply valve 26 according to the input cycle phase signal. The abnormality transmitting device 50 outputs an abnormal signal when it determines that the fuel supply valve 26 is abnormal.

3 is a partially cutaway front view illustrating a mounting position of the pressure sensor 51 shown in FIG. 1. The fuel header 25 is provided with a branch pipe 28 corresponding to each cylinder. The fuel supply pipe 29 is connected to the end of the branch pipe 28 through a throttle 34. In addition, the end of the fuel supply pipe 29 is connected to the inlet of the fuel supply valve 26. The outlet of the fuel supply valve 26 is opened to the air supply port 13.

The pressure sensor 51 is attached to the side of the fuel supply pipe 29 downstream of the throttle 34, for example, in a position directly below. The pressure sensor 51 detects the pressure in the fuel supply pipe 29 corresponding to the static pressure of the mounting position, and transmits a pressure signal to the abnormal transmission device 50.

4 is a graph illustrating an example of a pressure change of the fuel supply pipe 29 illustrated in FIG. 1. 4 shows the results of measurements on a gas engine that is normally operated as usual, taking the elapsed time on the horizontal axis, taking the rotational speed on the right vertical axis, and the gaseous fuel in the fuel header 25 on the left vertical axis. The differential pressure obtained by subtracting the pressure of the fuel supply pipe 26 from the pressure (continuous pressure) is taken. The upper points are the rotation speed at the top dead center position of the piston 12. The lower line represents the change in the differential pressure (change in the constant pressure equivalent pressure of the gaseous fuel in the fuel supply pipe 29).

The gaseous fuel pressure in the fuel supply pipe 29 is rapidly reduced in pressure between the fuel supply valve 26 being opened in the air supply stroke and supplying the gaseous fuel during the air supply, and thereafter, the gaseous fuel pressure is rapidly recovered. In the valve closing period, the pressure is approximately equal to the pressure. The pressure of the fuel supply pipe 29 in the valve opening period decreases by about 7 kPa each time. As the number of revolutions of the crankshaft 21 increases, the pressure of the fuel supply pipe 29 also increases, but the increase rate is small, and does not prevent the grasp of the decompression situation due to the opening and closing of the fuel supply valve 26.

5 is a graph for explaining the principle of gaseous fuel leak detection in the gaseous fuel leak detection apparatus 100 and the gaseous fuel leak detection method according to the first embodiment of the present invention. FIG. 5: shows the state of the air supply valve 15, the exhaust valve 16, and the fuel supply valve 26 in the upper graph, and shows the pressure change of the fuel supply pipe 29 in the lower graph. When the fuel supply valve 26 cannot be normally closed in the valve closing period due to the foreign matter caught in the fuel supply valve 26, the pressure of the fuel supply pipe 29 is not restored to the pressure in the valve closing period. .

Therefore, the abnormality transmitting device 50 according to the present embodiment monitors the output of the pressure sensor 51 and generates an alarm when detecting the occurrence of such a pattern. By the way, the output of the pressure sensor 51 changes also between the value equivalent to soft pressure, and the value which the fuel supply valve 26 opened and decompressed, even when it is normal. For this reason, the abnormality transmitting device 50 according to the present exemplary embodiment detects the pressure detected within the valve closing period except for the period during which the pressure is reduced due to the valve opening of the fuel supply valve 26 during the output change of the pressure sensor 51. I use it.

Of the pressures detected within the valve closing period, the pressure detected at the time point near the bottom dead center in the air supply and compression stroke can be used. The valve opening period of the fuel supply valve 26 is set between immediately after the air supply valve 15 is opened and until the air supply valve 15 is closed. On the other hand, since the piston 12 passes through the bottom dead center and the compression stroke starts after the air supply valve 15 is closed, the fuel supply valve 26 is in the valve closed state at the start of the compression stroke. In addition, it is advantageous because the abnormality can be detected very quickly at the start of the compression stroke.

6 is a flowchart showing a process of the gaseous fuel leak detection method according to the first embodiment of the present invention. The flow shown in FIG. 6 is executed for every engine cycle. As shown in FIG. 6, the abnormality transmitting device 50 according to the present embodiment receives the rotation phase (cycle phase) information of the crankshaft from the engine control device 40 (S11), and supplies the target cylinder with air. The timing of the bottom dead center in the compression stroke is recognized or detected (S12). Then, the pressure signal of the pressure sensor 51 is received to extract the pressure value at the bottom dead center (S13). Then, the difference between the pressure of the fuel supply pipe 29 at the bottom dead center and the latest average value is obtained (S14), and when the differential pressure is lower than the threshold (threshold) set at, for example, about 2 to 3 kPa (S15). , It is determined that an abnormality has occurred in the fuel supply valve 26, and an abnormality detection signal is generated (S16). When the differential pressure is not large (S15), the measured pressure is added to calculate the latest average value (S17), and is prepared for the next determination.

In this embodiment, the pressure sensor 51 is provided downstream of the throttle 34. When gaseous fuel is supplied to the air supply, the flow rate of the gaseous fuel is increased by the throttle 34 so that the dynamic pressure is increased and the static pressure is greatly reduced. For this reason, when the pressure sensor 51 is provided downstream of the throttle 34, the recovery failure of the positive pressure at the time of leaking gaseous fuel can be detected favorably, and abnormal detection sensitivity will become high. In particular, when the pressure sensor 51 is provided at the position where the axial flow caused by the throttle 34 is most remarkable, the decrease in the static pressure is maximized and the above detection sensitivity is improved.

On the other hand, as shown in FIG. 4, since the soft pressure in the fuel header 25 may also change, so that the pressure of the fuel supply pipe 29 may be compared with the average value of the past measured value or several recent measured values. You may also do it. The average value used here may be a moving average value, or may be a weighted average value having a small importance gradually over an old measured value.

Moreover, you may make it judge by comparing with the soft-pressure value measured by the soft-pressure sensor 43 provided in the fuel header 25 directly. On the other hand, although the pressure sensor 43 may be provided for engine control even in a conventional gas engine, in this case, the sensor already installed can be used. The above-mentioned transmitter 50 may receive the crank angle signal directly from the rotational phase meter 41 provided in the crankshaft 21. The abnormal signal may be supplied to the engine control device 40 to start the emergency stop operation. Alternatively, the alarm may be stopped for the judgment of the operator.

In order to recognize the valve closing period of the fuel supply valve 26, there is also a method of using a drive command signal of the fuel supply valve 26 or a crank angle signal when the air supply valve 15 is closed. After the valve closing command is issued to the fuel supply valve 26, when an appropriate time elapses, the flow of the gaseous fuel is normally completely stopped, and the pressure of the fuel supply pipe 29 returns to the pressure of the fuel header 25. Therefore, recognition of the valve closing period becomes easy by acquiring the valve closing command signal (drive command signal) of the fuel supply valve 26 from the engine control device 40. On the other hand, since the fuel supply valve 26 will be closed when the air supply valve 15 is closed, when the air supply valve 15 is used as the solenoid valve, the timing at which the valve closing command signal of the air supply valve is issued is given. The occurrence of the abnormality can also be determined using the pressure signal of.

In addition, the abnormality transmitting apparatus in this embodiment may be constituted by a dedicated electronic circuit, or may be constituted by a general purpose microcomputer. Moreover, you may comprise as part of the electronic circuit which comprises the control apparatus for gas engines. In this embodiment, although the fuel supply valve 26 which injects gaseous fuel to the air supply port 13 is made into object, it is aimed at the other fuel supply valve, for example, the sub fuel supply valve provided in the inferior chamber 18. You may.

[Second Embodiment]

7 is a conceptual diagram showing the configuration of the gaseous fuel leak detecting apparatus 200 according to the second embodiment of the present invention. The gaseous fuel leak detection apparatus 200 according to the second embodiment is applied to the gas engine 10 for power generation, and gaseous fuel leaks from the fuel supply valve 26 in accordance with the oxygen concentration in the air supply port 13. Detect whether or not The gas engine 10 is provided with an oxygen concentration sensor 251 for each cylinder. Hereinafter, the gaseous fuel leak detection apparatus 200 according to the second embodiment will be described, focusing on differences from the above-described embodiment.

As shown in FIG. 7, the gaseous fuel leak detection device 200 includes an oxygen concentration sensor 251 for detecting the oxygen concentration in the air supply port 13 and a fuel supply valve in accordance with the oxygen concentration in the air supply port 13. The abnormality transmission device 250 which determines whether or not 26 is abnormal (more specifically, whether or not gaseous fuel is leaking from the fuel supply valve 26) is provided. The oxygen concentration sensor 251 detects the oxygen concentration contained in the air in the air supply port 13 and outputs an oxygen concentration signal indicating the detected oxygen concentration. The abnormality transmitting device 250 functions as a determining device that determines whether or not the fuel supply valve 26 is abnormal. For the determination, the abnormality transmitting device 250 inputs an oxygen concentration signal of the oxygen concentration sensor 251 and a cycle phase signal indicating the cycle phase. The abnormality transmitting device 250 compares the oxygen concentration detected by the oxygen concentration sensor 251 with a predetermined threshold value and determines that the fuel supply valve 26 is abnormal when the oxygen concentration is lower than the threshold value. . When the abnormality transmission device 250 determines that the fuel supply valve 26 is abnormal, it outputs an abnormal signal.

FIG. 8 is a partially cutaway front view illustrating a mounting position of the oxygen concentration sensor 251 shown in FIG. 7. As shown in FIG. 8, the fuel supply pipe 29 which measures and supplies gaseous fuel from the fuel header 25 is connected to the inlet of the fuel supply valve 26. As shown in FIG. The outlet of the fuel supply valve 26 is opened to the air supply port 13.

The oxygen concentration sensor 251 is installed on a downstream side wall very close to the fuel supply valve 26 at the air supply port 13 to measure the oxygen concentration in the air supply port 13 to abnormally transmit an oxygen concentration signal 50. To be sent). The oxygen concentration sensor 51 is provided not at a position to directly receive fuel injection from the fuel supply valve 26 but at a position before the injected gaseous fuel and air are mixed at a normal time. Therefore, when the fuel supply valve 26 is operating normally, the measurement output of the oxygen concentration sensor 51 becomes a value corresponding to the oxygen concentration of the air taken in as air supply.

However, when gaseous fuel flows into the air supply port 13 even during the valve closing period due to the foreign matter being caught in the fuel supply valve 26, the air supply stroke is completed and the air supply valve 15 closes the valve so that new air is supplied to the air supply port 13. When it does not flow in, the ratio of the gaseous fuel in the air supply staying in the air supply port 13 increases rapidly and the oxygen concentration decreases.

FIG. 9 is a graph showing the oxygen concentration in the air supply port 13 shown in FIG. 7. The engine speed and load are taken on the horizontal axis, and the oxygen concentration is taken on the vertical axis. 9 shows the oxygen concentration at the time when the fuel supply valve 26 is normal or abnormal (for example, when the fuel supply valve 26 is closed due to foreign matter being caught) and thus the engine speed and load parameters. A bar graph is shown. The oxygen concentration when the fuel supply valve 26 is abnormal is calculated by displaying a value at which fuel accumulates during one engine cycle.

While the engine speed is small, since the actual time period in which one engine cycle elapses increases the leakage time of the gaseous fuel, the residual amount of oxygen is further reduced and the oxygen concentration in the air supply port 13 is almost zero. Becomes As the engine speed increases, the leakage of gaseous fuel decreases and the decrease of oxygen concentration decreases every one engine cycle. Even when the engine speed is 722 rpm or 720 rpm, the oxygen concentration decreases by about 15% after one engine cycle has elapsed. Can be. Moreover, 722 rpm becomes the maximum value in a graph because the rotation speed is suitable for generating 50-60 kW of alternating current when the gas engine 10 is used for driving an alternator. When the gas engine for power generation is operating, the rotation speed is stabilized at 720 rpm, and the gas engine 10 is controlled in many cases. FIG. 9 suggests that the oxygen concentration is remarkably reduced even when only one engine cycle has elapsed after the leakage of the gaseous fuel in the normal continuous operation of the power generation gas engine 10.

10 is a graph for explaining the principle of the gaseous fuel leak detection method according to the second embodiment of the present invention. In FIG. 10, time is taken on the horizontal axis, oxygen is taken on the vertical axis, and the time change of the oxygen concentration in the air supply port 13 is conceptually shown. While the fuel supply valve 26 is normal, the oxygen concentration in the air supply port 13 is 20 to 21% which is almost equal to the atmosphere. Even when the fuel supply valve 26 is operated to inject gaseous fuel, the oxygen concentration detected by the oxygen concentration sensor 251 does not change very much. If an abnormality occurs in the fuel supply valve 26 and gaseous fuel leaks to the air supply port 13 even in the valve closing period, the oxygen concentration at the air supply port 13 decreases rapidly at the end of the air supply stroke. When the fuel-rich air supply reaches the next air supply stroke, it is pushed by fresh air sucked from outside air, and is supplied to a combustion chamber. At this time, as shown in FIG. 10, due to the relationship between the volume of the air supply port 13 and the volume of the combustion chamber, the mixer and the air of the air supply port 13 are changed, and thus the oxygen concentration is not reached. During the air supply stroke, even when all of the mixers of the air supply port 13 are replaced with new air supply, the oxygen concentration is again at the time when the air supply stroke ends, unless the failure that the fuel supply valve 26 leaks in the valve closed state is eliminated. Will drop dramatically.

In this way, the oxygen concentration in the air supply port 13 represents a value equivalent to air when the fuel supply valve 26 is normal, and suddenly when the air supply stroke ends when the fuel supply valve 26 is broken. Since it lowers easily, it is possible to set an appropriate threshold value and determine that there is an abnormality when the oxygen concentration falls below the threshold value. The threshold value of the oxygen concentration may be appropriately selected according to the engine speed. For example, when the threshold value is 17%, the threshold value can be used even if the speed is 720 rpm.

On the other hand, depending on the characteristic of the oxygen concentration sensor 51 and the installation situation in the air supply port 13, the detected oxygen concentration may decrease by fuel injection. In such a case, judging only according to the oxygen concentration reduction amount, there is a possibility that the normal fuel supply valve 26 is mistaken for abnormality. Therefore, the timing of monitoring the oxygen concentration is set at an appropriate cycle phase time point, so that the noise of the oxygen concentration decrease phenomenon due to the injection can be avoided so that the oxygen concentration decrease can be regarded as caused by the abnormality of the fuel supply valve 26. In this case, the correct judgment can be made. Thus, in order to extract the oxygen concentration detection result at the time suitable for abnormality determination, the abnormality transmission apparatus 250 inputs a cycle phase signal and uses it for recognition of the said time.

The phenomenon that the oxygen concentration of the air supply port 13 decreases due to the abnormality of the fuel supply valve 26 may be, for example, a piston at which the timing immediately after the air supply valve 15 is closed or the compression stroke after the air supply starts ( By using the oxygen concentration at the timing near the bottom dead center position in 12), it can be reliably detected. For this reason, it is possible for the abnormality transmitter 250 to further receive the cycle phase information to avoid the timing of fuel injection and to evaluate the decrease in oxygen concentration after the air supply valve 15 is closed.

The cycle phase information may be directly received from the rotational phase meter 41 provided on the crankshaft 21 and used for designation of the time for evaluating the oxygen concentration. In addition, the engine control device 40 supplies a valve closing command signal (driving command signal) of the fuel supply valve 26, and generates a command signal for the valve using the bottom dead center passage information of the piston 12, or Therefore, the abnormality transmitting device 250 may input and use the valve closing command signal (drive command signal) of the fuel supply valve 26 or the bottom dead center passage information of the piston 12 from the engine control device 40. good.

This determination process is simple, but if an abnormality occurs in the fuel supply valve 26, since it can be detected immediately after the air supply stroke is completed, it is possible to take appropriate measures before seriously affecting the post-treatment process of the exhaust gas. .

After the abnormality transmitting device 250 supplies a signal to the engine control device 40 to notify the occurrence of an abnormality when the abnormality is detected, the engine control device 40 immediately takes an action to emergency stop the engine. It can be prevented beforehand.

In addition, the abnormal originating apparatus 250 notifies the occurrence of the abnormality without directly connecting the abnormal originating apparatus 250 and the engine control apparatus 40, and the operator receives the notification and takes appropriate measures through the engine control apparatus 40. May be performed.

11 is a graph for explaining the principle of gaseous fuel leak detection in the gaseous fuel leak detecting apparatus 200 and the gaseous fuel leak detecting method according to the second embodiment of the present invention. 11 shows a crank angle of zero when the piston is at the top dead center on the horizontal axis, oxygen concentration on the vertical axis, and an abnormality in the fuel supply valve 26 occurs when the gas engine 10 starts up. Taking the situation as an example, it shows conceptually the time change of oxygen concentration. Under such a situation, the oxygen concentration in the air supply port 13 decreases with time. It can be seen that the oxygen concentration, which was about 19% at first, is rapidly reduced to almost zero at the crank angle of 240 kPa, and the fuel leakage can be sufficiently detected within one revolution as the oxygen concentration decreases. have. Even if foreign matters are mixed into the fuel supply valve 26 at the time of reconstruction after overhaul, it can be seen that the foreign matters can be detected quickly and with high accuracy when the gas engine 10 is restarted.

12 is a flowchart showing a process of the gaseous fuel leak detection method according to the second embodiment of the present invention. The flow shown in FIG. 12 is executed every engine cycle. As shown in FIG. 12, the abnormality transmitting device 250 according to the present embodiment receives the cycle phase information from the engine control device 40 (S211), for example, the air supply and compression stroke of the target cylinder. When the valve closing period of the air supply valve 15, such as the bottom dead center timing, is received (S212), the oxygen concentration signal of the oxygen concentration sensor 51 is received (S213). This oxygen concentration is compared with a predetermined threshold (S214). If the oxygen concentration is lower than the predetermined threshold, it is determined that an abnormality has occurred in the fuel supply valve 26, and an abnormal signal is generated (S215). On the other hand, when the present time is not the valve closing period of the air supply valve 15 (S212), or when the oxygen concentration is higher than the threshold value (S214), the process returns to the first stage and returns to the first stage S211 again. Enter the first operation in the next work process. The abnormal signal may be supplied to the engine control device 40 to start an emergency stop operation. Alternatively, the alarm may be stopped for the judgment of the operator.

The process shown in FIG. 12 allows the abnormality transmitting device 250 to select a timing for evaluating the oxygen concentration measurement value in accordance with the phase signal received from the engine control device 40. If the oxygen concentration sensor 251 does not respond to the decrease in concentration at the time of normal fuel injection, the processes S211 and S212 according to the phase signal are unnecessary. In addition, the cycle phase signal may be directly received by the abnormal transmission device 250 from the rotational phase meter 41 provided on the crankshaft 21.

In order to recognize the valve closing period of the fuel supply valve 26, there is also a method of using an operation command signal of the fuel supply valve 26 or a cycle phase signal at the time of closing the valve of the air supply valve 15. For example, after a command for closing the fuel supply valve 26 is issued, when an appropriate time elapses, the flow of gaseous fuel is usually completely stopped, and the oxygen concentration of the air supply port 13 is returned to the oxygen concentration of air almost. come. Therefore, when the valve closing command signal of the fuel supply valve 26 is received from the engine control apparatus 40, the timing signal used for determination can be obtained simply. Alternatively, since the air supply valve 15 is closed after a suitable time has elapsed after the fuel supply valve 26 is closed, the cycle phase signal when the air supply valve 15 is closed or closed is used. Also good.

In addition, the abnormality transmitting apparatus in this embodiment may be constituted by a dedicated electronic circuit, or may be constituted by a general purpose microcomputer. In addition, you may make it comprise a part of electronic circuit which comprises the control apparatus for gas engines.

Third Embodiment

13 is a conceptual diagram showing the configuration of the gaseous fuel leak detection apparatus 300 according to the third embodiment of the present invention. The gaseous fuel leak detection apparatus 300 according to the present embodiment determines whether or not gaseous fuel is leaking from the fuel supply valve 26 based on the strength of vibration resulting from the opening and closing of the fuel supply valve 26. The gas engine 10 is provided with a vibration sensor 351 for each cylinder. Hereinafter, the gaseous fuel leak detection apparatus 300 according to the third embodiment will be described, focusing on differences from the above-described embodiments.

As shown in FIG. 13, the gaseous fuel leak detection apparatus 300 according to the present embodiment includes a vibration sensor 351 installed in the fuel supply valve 26 and detecting a vibration intensity of the fuel supply valve 26. The abnormality of determining whether or not the fuel supply valve 26 is abnormal (more specifically, whether or not foreign matter is stuck in the fuel supply valve 26) based on the vibration intensity according to the opening and closing of the fuel supply valve 26. Apparatus 350 is provided. In addition, the abnormality transmission device 351 is provided with the opening / closing signal supply apparatus which supplies the signal which shows the opening / closing timing of the fuel supply valve 26, In this embodiment, the rotary phase meter 41 supplies the opening-closing vibration. Function as a device. The vibration sensor 351 detects the vibration intensity of the fuel supply valve, and outputs a vibration measurement signal indicating the detected vibration intensity. The abnormality transmitting device 350 functions as a determining device that determines whether or not the fuel supply valve 26 is abnormal. For determination, the abnormality transmitting device 350 inputs the vibration measurement signal of the vibration sensor 351, and further, from the rotational phase meter 41, the rotational phase of the crankshaft 21 as a signal indicating the opening and closing timing. Input the signal indicated. The abnormality transmitting device 350 outputs an abnormal signal when it is determined that the fuel supply valve 26 is abnormal.

14 is a cross-sectional view conceptually showing the structure of the fuel supply valve 26 shown in FIG. 15 is a cross-sectional view illustrating a mounting position of the vibration sensor 351 shown in FIG. 13. As shown in FIG. 14 and FIG. 15, a fuel supply pipe 29 for supplying gaseous fuel from the fuel header 25 is connected to the inlet of the fuel supply valve 26. The outlet of the fuel supply valve 26 is opened to the air supply port 13, and when the fuel supply valve 26 is opened, gaseous fuel is injected into the air supply port 13, whereby the gaseous fuel is mixed into the air supply.

The vibration sensor 351 is mounted on a side wall near the valve seat position of the fuel supply valve 26 (the outer wall of the enclosure of the fuel supply valve 26) to measure vibration generated by opening and closing of the fuel supply valve 26. The measured vibration is transmitted to the abnormal transmission device 350. As the vibration due to the opening and closing, for example, vibration when the magnetic core of the valve body 45 and the electromagnet 43 collide, and vibration when the valve body 45 and the valve seat 46 collide with each other. have.

However, the engine is generating vibrations of various sizes, and the vibrations that can be used for abnormality determination in the fuel supply valve 26 have collided with the valve body 45 of the fuel supply valve 26 and the valve seat 46. Only vibration of time. In addition, the vibration generated due to the collision between the valve body 45 and the valve seat 46 is small in stroke and not necessarily large. Thus, as the signal processing device provided in the abnormal transmission device 350 extracts only the vibrations synchronized with the timing of occurrence of such a collision from the vibration measurement signals input from the vibration sensor 351, the fuel supply valve 26 is opened and closed. After detecting the signal indicating the vibration according to the change in the vibration level (level) to detect the pinch of the foreign matter. The abnormality transmitting device 350 inputs a signal indicating the opening and closing timing, and uses the signal for the extraction and classification processing.

Fig. 16 is a graph for explaining the principle of gaseous fuel leak detection in the gaseous fuel leak detection apparatus 300 and the gaseous fuel leak detection method according to the third embodiment of the present invention. 16 takes time on the horizontal axis. In the upper graph, the state of the valve is taken on the vertical axis, and the opening and closing timing of the fuel supply valve 26 is shown. In the graph of the interruption, the acceleration level (that is, the vibration intensity) detected by the vibration sensor 351 on the vertical axis is taken to conceptually represent the change in vibration intensity at the normal time. In the lower graph, the acceleration level (that is, vibration intensity) detected by the vibration sensor 351 is taken on the vertical axis, and conceptually shows the change in vibration intensity at the time of abnormality.

The change in the vibration intensity shown in FIG. 16 shows only the vibration intensity according to the opening and closing of the fuel supply valve 26 for the convenience of explanation. In practice, opening and closing from the vibration signal output from the vibration sensor 351 by applying a time filter in which the window is opened only for a suitable period before and after the valve opening command signal and the valve closing command signal for the fuel supply valve 26 are issued. It is possible to extract the intensity of the vibration. The valve opening command signal and the valve closing command signal are calculated according to the rotational phase of the crankshaft 21 detected by the rotational phase meter 41 so that the engine control device 40 supplies the fuel supply valve 26 to the fuel supply valve 26. At the same time, only by supplying the abnormal transmission device 350, the abnormal transmission device 350 can recognize the opening / closing timing of the fuel supply valve 26 to generate a time filter having a duration duration of vibration.

Moreover, the output signal of the rotational phase meter 41 is supplied to the abnormality transmission device 350 directly or via the engine control device 40, so that the abnormality transmission device 350 itself depends on the rotational phase of the crank shaft 21. The above-described time filter may be generated. The vibrations at the time of valve opening and the valve closing of the fuel supply valve 26 at the normal time are generated repeatedly at almost the same intensity. On the contrary, when the valve is closed in a state in which foreign matter is caught between the valve body 45 and the valve seat 46, the cushioning material exists between the surfaces where the planes of the valve body 45 and the valve seat 46 collide with each other. As a result, the intensity of vibration and noise generated due to the collision between the valve body 45 and the valve seat 46 is reduced. On the other hand, the vibration state when the magnetic body of the valve body and the magnetic core of the electromagnet 43 collide with the valve opening of the fuel supply valve 26 does not change very much.

Therefore, paying particular attention to vibration in closing the valve, it is possible to determine that pinch of foreign matter occurred when the vibration intensity became weaker than usual. The weakening of the vibration intensity can be detected by comparing with the vibration level at the time of closing the valve before that. In addition, it is possible to find an appropriate threshold value in advance and determine that an abnormality has occurred in the fuel supply valve 26 when the vibration intensity is smaller than the threshold value. When an error is detected, an error signal is sent.

Although this determination process is simple, if an abnormality occurs in the fuel supply valve 26, the abnormality can be detected almost simultaneously with the leakage of gaseous fuel, so that appropriate countermeasures must be taken before seriously affecting the post-treatment process of the exhaust gas. I can afford to take it.

When the abnormality transmitting device 350 supplies the engine control device 40 with an abnormal signal notifying the occurrence of an abnormality when the abnormality is detected, the engine control device 40 immediately takes an emergency stop of the engine. Combustion of the mixer in the fold 34 does not occur, and it is possible to prevent damage to the respective devices in the exhaust gas treatment process. In addition, the abnormality transmitting device 50 notifies the engine control device 40 of the abnormal signal generated by the abnormal transmitting device 50 directly, and the operator receives the notification and receives the notification. 40), appropriate measures may be taken.

17 is a flowchart showing a process of the gaseous fuel leak detection method according to the third embodiment of the present invention. The flow shown in FIG. 17 is executed every engine cycle. As shown in FIG. 17, the abnormality transmitting device 350 according to the present embodiment receives the cycle phase information obtained according to the rotational phase of the crankshaft from the engine control device 40 (S311) and the fuel supply valve 26. The valve closing timing () is recognized (S312), and vibration generated from the valve seat 46 at the time of closing the valve is extracted from the vibration measurement signal supplied from the vibration sensor 351 (S313). The vibration thus extracted is compared with a threshold value (S314), and when the vibration intensity is lower than the threshold value, it is determined that an abnormality has occurred in the fuel supply valve 26, and an abnormal signal is generated (S315). On the other hand, when the present time is not the valve closing timing of the fuel supply valve 26 (S312), or when the vibration intensity is higher than the threshold value (S314), the process returns to the first step S311 again to start the next work process. . The abnormal signal may be supplied to the engine control device 40 to start the emergency stop operation. Alternatively, the alarm may be stopped for the judgment of the operator.

The process shown in FIG. 17 causes the abnormality transmission device 350 to select a timing for evaluating the vibration of the fuel supply valve 26 in accordance with the phase signal received from the engine control device 40. Instead, the abnormal transmission device 350 may receive the cycle phase information directly from the rotational phase meter 41 provided on the crankshaft 21. Moreover, the valve closing command signal of the fuel supply valve 26 supplied from the engine control apparatus 40 can also be received and used.

In addition, the abnormality transmitting apparatus in this embodiment may be constituted by a dedicated electronic circuit, or may be constituted by a general purpose microcomputer. In addition, you may make it comprise a part of electronic circuit which comprises the control apparatus for gas engines. In addition, in this embodiment, although the fuel supply valve 26 which injects gaseous fuel to the air supply port 13 is made into object, the other fuel supply valve, for example, the sub fuel injection valve provided in the sub chamber 18 is used. You can also target.

[Modifications]

Although this embodiment demonstrates an invention using the 4-cycle gas engine provided with an inferiority as an example, it cannot be overemphasized that the technical idea which concerns on this invention can be applied, even if there is no insolvency and even a 2-cycle engine. . The gas engine described in the drawings drives a generator, but may be used for driving a vehicle or a ship by driving wheels, screws, or the like.

Many improvements and other embodiments of the present invention will be apparent to those skilled in the art from the foregoing description. The foregoing description, therefore, is to be construed as illustrative only and is provided for the purpose of teaching those skilled in the art preferred embodiments of the invention. The details of the structure and / or function can be substantially changed without departing from the spirit of the present invention.

According to the present invention, the fuel supply valve cannot be normally closed, so that even if the gaseous fuel leaks, the fuel supply valve can be detected quickly, thereby exerting the effect of quickly dealing with such an abnormality, thereby providing a gas engine, It is particularly advantageous when applied to a gas engine for power generation.

100,200, 300: gaseous fuel leakage device
50, 250, 350: abnormal calling device (judgment device)
10: gas engine
12: piston
13: air supply port
21: crankshaft
25: fuel header
26: fuel supply valve
28: fuel supply pipe (branch pipe)
29: fuel supply pipe
34: throttle
40: engine control unit
41: rotational phase meter
43: pressure sensor
51: pressure sensor
251: oxygen concentration sensor
351: vibration sensor

Claims (18)

A method for detecting gaseous fuel leakage from a fuel supply valve for a gas engine, the method comprising:
The pressure of the fuel supply line for supplying gaseous fuel from the fuel header to the fuel supply valve is detected within the valve closing period of the fuel supply valve, and based on the detected pressure, or
Detecting an oxygen concentration in the air supply port which is supplied with gaseous fuel from the fuel supply valve, and based on the detected oxygen concentration, or
By using the vibration sensor provided in the fuel supply valve to detect the intensity of the vibration according to the opening and closing of the fuel supply valve, based on the detected intensity of vibration,
It is determined whether gaseous fuel is leaking from the fuel supply valve.
An apparatus for detecting gaseous fuel leakage from a fuel supply valve for a gas engine, the apparatus comprising:
A pressure sensor detecting a pressure of a fuel supply pipe connecting a fuel header to the fuel supply valve;
And a judging device for judging whether or not gaseous fuel is leaking from said fuel supply valve on the basis of the pressure detected by said pressure sensor within the valve closing period of said fuel supply valve.
The method of claim 2,
The fuel supply pipe has a throttle, and the pressure sensor detects a pressure downstream from the throttle.
The method of claim 2,
And a soft pressure sensor for detecting the pressure of the gaseous fuel in the fuel header,
And the judging device determines whether or not gaseous fuel is leaking based on a differential pressure between the pressure detected by the pressure sensor and the pressure detected by the soft pressure sensor.
The method of claim 2,
A rotational phase meter for detecting the rotational phase of the crankshaft of the gas engine,
And the judging device recognizes the valve closing period based on the rotational phase detected by the rotational phase meter.
The method of claim 2,
The determination device recognizes the valve closing period based on a drive command signal of the fuel supply valve.
The method of claim 2,
And when the pressure detected by the pressure sensor in the valve closing period is lower than the pressure detected by the pressure sensor in the valve closing period before it, the determination device determines that gaseous fuel is leaking. Gas fuel leak detection device.
The method of claim 2,
And a pressure detected by the pressure sensor within the valve closing period is a pressure detected by the pressure sensor when the piston of the gas engine is located near the bottom dead center.
An apparatus for detecting gaseous fuel leakage from a fuel supply valve for a gas engine, the apparatus comprising:
An oxygen concentration sensor for detecting an oxygen concentration in the air supply port receiving gas fuel from the fuel supply valve;
And a judging device for judging whether or not gaseous fuel is leaking from the fuel supply valve based on the oxygen concentration detected by the oxygen concentration sensor.
10. The method of claim 9,
And the determination device compares the oxygen concentration detected by the oxygen concentration sensor with the threshold value when the rotational phase of the crankshaft of the gas engine is a predetermined phase.
The method of claim 10,
A rotational phase meter for detecting a rotational phase of the crankshaft,
And the determination device receives a rotational phase detected by the rotational phase meter directly from the rotational phase meter or indirectly through an engine control device of the gas engine.
10. The method of claim 9,
And the determination device determines that the gaseous fuel is leaking when the detected oxygen concentration is lower than a predetermined threshold.
An apparatus for detecting gaseous fuel leakage from a fuel supply valve for a gas engine, the apparatus comprising:
A vibration sensor installed at the fuel supply valve and detecting a vibration intensity of the fuel supply valve;
And a judging device for judging whether or not gaseous fuel is leaking from said fuel supply valve on the basis of the vibration intensity according to opening and closing of said fuel supply valve detected by said vibration sensor.
The method of claim 13,
An opening / closing signal supply device for supplying a signal indicating an opening / closing timing of the fuel supply valve, wherein the determination device recognizes the opening / closing of the fuel supply valve based on a signal supplied from the opening / closing signal supply device,
The open / close signal supply device is an engine control device of the gas engine, and the signal representing the open / close timing of the fuel supply valve is a drive command signal of the fuel supply valve input from the engine control device. Leakage detection device.
The method of claim 13,
An opening / closing signal supply device for supplying a signal indicating opening / closing timing of the fuel supply valve, wherein the determination device recognizes the opening / closing timing of the fuel supply valve based on a signal supplied from the opening / closing signal supply device,
The on-off signal supply device and a rotational phase meter for detecting the rotational phase of the crankshaft of the gas engine, the signal indicating the opening and closing timing of the fuel supply valve is a rotational phase signal indicating the rotational phase of the crankshaft, And a gaseous fuel leak detection device which receives the rotational phase signal directly from the rotational phase meter or indirectly through an engine control device of the gas engine.
The method of claim 13,
And the determination device determines that gaseous fuel is leaking when the vibration intensity according to the opening and closing of the fuel supply valve detected by the vibration sensor is equal to or less than a predetermined threshold value.
The method of claim 13,
When the vibration intensity according to the opening and closing of the fuel supply valve detected by the vibration sensor is lowered to a predetermined value or more in comparison with the previous one, the judging device determines that the gaseous fuel is leaking. Fuel Leak Detection Device.
The gas engine provided with the gaseous fuel leak detection apparatus in any one of Claims 2-17.

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