JP2009108763A - Gas fuel supply device and pressure drop pipe specifying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas fuel supply device capable of successively supplying gas fuel to an engine, even when a pressure drop is caused in a pipe for supplying the gas fuel to the engine. <P>SOLUTION: In a first fuel supply part 24, a fuel supply main pipe 42 and a fuel supply sub-pipe 44 are arranged in parallel in the fuel supply direction. Even in a second fuel supply part 26, a fuel supply main pipe 46 and a fuel supply sub-pipe 48 are arranged in parallel in the fuel supply direction. The fuel is normally supplied to the engine 20 by the fuel supply main pipes 42 and 46. When the pressure drop is caused in the fuel supply main pipe 46, fuel cutoff valves 84 and 88 are closed, and a fuel cutoff valve 92 is opened, and the fuel can be successively supplied by using the fuel supply sub-pipe 48 instead of the fuel supply main pipe 46. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gaseous fuel supply apparatus.

  In a gaseous fuel supply device that supplies gaseous fuel such as compressed natural gas (CNG) to an engine, as described in, for example, Patent Document 1 and the like, when a sudden pressure change occurs in a high-pressure pipe, Is closed to prevent the outflow of fuel gas.

However, in the configuration of Patent Document 1, since the container base valve is closed when a pressure change occurs, the gaseous fuel cannot be supplied to the engine thereafter.
Japanese Patent Laid-Open No. 10-252568

  In consideration of the above facts, the present invention provides a gaseous fuel supply device capable of continuously supplying gaseous fuel to the engine even when a pressure drop occurs in a pipe for supplying gaseous fuel to the engine, and the gaseous fuel. An object of the present invention is to obtain a pressure drop piping specifying method for specifying a pipe in which a pressure drop has occurred in a supply device.

  In the first aspect of the invention, a fuel tank in which gaseous fuel is accommodated, a fuel supply main pipe capable of supplying the gaseous fuel accommodated in the fuel tank to the engine, and the fuel supply main pipe are arranged in parallel. A fuel supply sub-pipe that can supply the gaseous fuel accommodated in the fuel tank to the engine, a parallel pipe set including a main pipe pressure sensor that detects a pressure in the fuel supply main pipe, and the main pipe And switching means for switching the pipe used for fuel supply to the engine from the fuel supply main pipe to the fuel supply sub pipe when the pressure in the fuel supply main pipe detected by the pipe pressure sensor decreases.

  In this gaseous fuel supply device, a fuel supply main pipe and a fuel supply sub pipe are arranged in parallel to form a parallel pipe set, and the gaseous fuel accommodated in the fuel tank is supplied to the engine through the fuel supply main pipe. The The pressure in the fuel supply main pipe is detected by the main pipe pressure sensor, and when the pressure in the fuel supply main pipe detected by the main pipe pressure sensor decreases, the switching means The pipe used for fuel supply is switched from the fuel supply main pipe to the fuel supply sub pipe. Thereby, even if a pressure drop occurs in the fuel supply main pipe, the fuel can be continuously supplied to the engine by the fuel supply sub pipe.

  In the parallel pipe set, the number of pipes arranged in parallel is not particularly limited. For example, two or more fuel supply sub pipes may be provided, but considering the frequency of pressure drop in the fuel supply main pipe, One fuel supply sub-pipe is often sufficient, and from the viewpoint of simplifying the structure, one fuel supply sub-pipe is sufficient.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, a plurality of the parallel pipe sets are provided in series between the fuel tank and the engine.

  In this way, by providing a plurality of parallel piping sets between the fuel tank and the engine, the fuel supply piping set in which the pressure drop has occurred is specified, and only in the fuel supply piping set, the corresponding fuel supply main piping (pressure Since it is only necessary to repair the fuel supply main pipe) or the fuel supply sub-pipe in which the reduction has occurred and to take necessary measures, the time and cost required for these can be reduced.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the switching means is a first shut-off valve disposed upstream of the main pipe pressure sensor in the fuel supply main pipe. And a second shutoff valve disposed downstream of the main pipe pressure sensor in the fuel supply main pipe, and a third shutoff valve disposed in the fuel supply sub pipe.

  Therefore, in the normal state, the first shut-off valve and the second shut-off valve are opened, and the third shut-off valve is closed, so that the fuel supply main pipe is used and the fuel supply sub-pipe is not used. Can be supplied to institutions.

  Here, when the main pipe pressure sensor detects a pressure drop, the first shut-off valve and the second shut-off valve are closed, and the third shut-off valve is opened to use the fuel supply sub-pipe and Piping can supply fuel to the engine without using it. In particular, an upstream first shut-off valve and a downstream second shut-off valve are provided in the fuel supply main pipe, and both of them are closed so that the fuel flows into the fuel supply main pipe between these shut-off valves. Can be prevented.

  According to a fourth aspect of the invention, in the first aspect of the invention according to any one of the first to third aspects, the fuel supply main pipe is configured to first prevent backflow of gaseous fuel from the downstream side to the upstream side. A check valve is arranged.

  Therefore, when the fuel supply sub-pipe is used and the fuel supply sub-pipe is damaged and the fuel supply sub-pipe is damaged, it is possible to prevent the fuel from flowing from the fuel supply main pipe to the fuel supply sub-pipe.

  According to a fifth aspect of the present invention, the fuel tank according to any one of the first to fourth aspects is provided with a plurality of the fuel tanks, and each of the plurality of the fuel tanks is connected to the most upstream parallel pipe. A fuel delivery pipe for delivering gaseous fuel to the set; a delivery pipe pressure sensor provided in each of the fuel delivery pipes; and a delivery pipe disposed upstream of the delivery pipe pressure sensor in each of the fuel delivery pipes A shutoff valve; and a second check valve that is disposed downstream of the delivery pipe pressure sensor in each of the fuel delivery pipes and prevents the backflow of gaseous fuel from the downstream side to the upstream side. To do.

  Accordingly, fuel can be sent from the plurality of fuel tanks to the parallel pipe set via the respective fuel delivery pipes.

  Each of the fuel delivery pipes is provided with a delivery pipe pressure sensor. When the pressure in one of the fuel delivery pipes decreases, the delivery pipe shut-off valve is closed to close the fuel delivery pipe where the pressure drop has occurred. You can stop using it. Moreover, since the second check valve is arranged downstream of the delivery pipe pressure sensor, the pressure of fuel gas from the downstream side to the upstream side, i.e., from the fuel delivery pipe where no pressure drop has occurred, is increased. It is possible to prevent the fuel from flowing into the fuel delivery pipe where the decrease has occurred.

  According to a sixth aspect of the present invention, there is provided a pressure drop piping specifying method for specifying in the gaseous fuel supply device according to the fourth aspect of the fuel supply main pipe or the fuel supply auxiliary pipe whether the pressure drop has occurred. When the pressure drop per unit time detected by the main pipe pressure sensor is larger than a set threshold value, a pressure drop occurs in the fuel supply main pipe, and when the pressure drop amount is smaller than the threshold value, the pressure is reduced in the fuel supply sub pipe. It is characterized by specifying that the decrease has occurred.

  That is, when a pressure drop occurs in the fuel supply main pipe, the amount of pressure drop per unit time detected by the main pipe pressure sensor becomes relatively large. On the other hand, when a pressure drop occurs in the fuel supply sub-pipe, the first check valve prevents the backflow of gaseous fuel from the downstream side to the upstream side, and the fuel is supplied from the fuel supply main pipe. Since it does not go into the secondary pipe, the pressure drop per unit time detected by the main pipe pressure sensor installed in the fuel supply main pipe falls only in accordance with the amount of fuel consumed by the engine, and the pressure drop is relative Become smaller.

  In this way, a threshold is set by utilizing the fact that the pressure drop per unit time detected by the main pipe pressure sensor differs depending on whether the pressure drop occurs in the fuel supply main pipe or the fuel supply sub pipe. The fuel supply pipe in which the pressure drop has occurred can be identified simply by comparing the magnitude with the threshold value.

  Since the present invention has the above-described configuration, even when a pressure drop occurs in a pipe that supplies the gaseous fuel to the engine, the gaseous fuel supply device that can continuously supply the gaseous fuel to the engine, and the gaseous fuel. In the supply device, a pressure drop piping specifying method for specifying a pipe in which a pressure drop has occurred is obtained.

  FIG. 1 shows a schematic configuration of a gaseous fuel supply device 12 according to the first embodiment of the present invention. This gaseous fuel supply device 12 is applied to an automobile that uses compressed natural gas (CNG) as fuel.

  The gaseous fuel supply device 12 has a plurality (two in this embodiment) of fuel tanks 14A and 14B in which compressed natural gas (CNG) is accommodated, and the fuel in these fuel tanks 14A and 14B is Supplied to the engine 20. In the fuel gas fuel supply device 12 of the present embodiment, the fuel delivery unit 22, the first fuel supply unit 24, the second fuel supply unit 26, and the most downstream fuel supply unit 28 are configured in order from the upstream side along the supply path. Has been. Each of the fuel tanks 14 </ b> A and 14 </ b> B can be filled with fuel from a fuel filling port 30 via a fuel filling pipe 32.

  In the fuel delivery part 22, fuel delivery pipes 18A and 18B are connected to the fuel tanks 14A and 14B via fuel cutoff valves 16A and 16B, respectively. The fuel delivery pipes 18 </ b> A and 18 </ b> B are arranged in parallel in the fuel delivery unit 22, but are integrated into one on the upstream side of the connection portion 34 with the first fuel supply unit 24.

  Further, the first fuel supply unit 24 also has a fuel supply main pipe 42 and a fuel supply sub-pipe 44 that are branched into two from the connection part 34 to the fuel delivery part 22. The fuel supply main pipe 42 and the fuel supply sub pipe 44 are integrated into one on the downstream side of each other, and reach the second fuel supply section 26 at the connection portion 36. Therefore, the fuel supply main pipe 42 and the fuel supply sub pipe 44 are arranged in parallel with respect to the fuel supply direction, and the parallel pipe set according to the present invention is configured.

  Similarly, the second fuel supply unit 26 also includes a fuel supply main pipe 46 and a fuel supply sub pipe 48 that are branched into two from a connection portion 36 with the first fuel supply unit 24. The fuel supply main pipe 46 and the fuel supply sub pipe 48 are integrated into one at the downstream connection portion 38 and connected to the fuel supply pipe 50 of the most downstream fuel supply unit 28. Therefore, in the second fuel supply unit 26, the fuel supply main pipe 46 and the fuel supply sub pipe 48 are arranged in parallel in the fuel supply direction, and the parallel pipe set according to the present invention is configured. .

  As a fuel supply path from the fuel tanks 14A and 14B to the engine 20, the fuel delivery unit 22, the first fuel supply unit 24, the second fuel supply unit 26, and the most downstream fuel supply unit 28 are connected from the upstream side to the downstream side. It will be arranged in series.

  Here, in the fuel delivery pipes 18A and 18B of the fuel delivery section 22, pressure sensors 52A and 52B and check valves 56A and 56B are arranged in order from the upstream side at a position close to the connection portion 34 (that is, downstream of each pipe). Is provided. The pressure sensors 52A and 52B can detect the fuel pressure in the respective fuel delivery pipes 18A and 18B. Further, the check valves 56A and 56B allow only the movement of fuel from the upstream side to the downstream side in each fuel delivery pipe 18A and 18B, and prevent the movement of fuel in the opposite direction.

  The fuel supply main pipe 42 of the first fuel supply unit 24 is provided with a check valve 62 and a fuel cutoff valve 64 in order from the upstream side in the vicinity of the connection portion 34 (upstream side of the fuel supply main pipe). Further, the fuel supply main pipe 42 of the first fuel supply unit 24 is provided with a pressure sensor 66 and a fuel cutoff valve 68 in order from the upstream side in the vicinity of the connection portion 36 (on the downstream side of the fuel supply main pipe 42). Yes.

  In contrast, the fuel supply sub-pipe 44 of the first fuel supply unit 24 is provided with a fuel cutoff valve 72 and a check valve 74 in order from the upstream side in the vicinity of the connection portion 36. The check valve 74 allows only the fuel movement from the upstream side to the downstream side in the fuel supply sub-pipe 44 and prevents the fuel movement in the opposite direction.

  In the second fuel supply unit 26, similarly to the first fuel supply unit 24, a check valve 82 and a fuel cutoff valve 84 are provided in the fuel supply main pipe 46 in the vicinity of the connection portion 36 in order from the upstream side. ing. Furthermore, a pressure sensor 86 and a fuel cutoff valve 88 are provided in the fuel supply main pipe 46 of the second fuel supply unit 26 in the vicinity of the connection portion 38 in order from the upstream side.

  In contrast, the fuel supply sub-pipe 48 of the second fuel supply unit 26 is provided with a fuel cutoff valve 92 and a check valve 94 in order from the upstream side in the vicinity of the connection portion 38. The check valve 94 allows only the movement of fuel from the upstream side to the downstream side in the fuel supply sub-pipe 44 and prevents the movement of fuel in the opposite direction.

  A pressure reducing valve 102 and a pressure sensor 104 are provided in the fuel supply pipe 50 of the most downstream fuel supply unit 28. The pressure reducing valve 102 has a function of reducing the pressure of the fuel in the fuel supply pipe 50 until it becomes a predetermined value or less and sending it to the engine 20. The pressure sensor 104 detects the fuel pressure in the fuel supply pipe 50.

  The pressure data detected by the pressure sensors 52A, 52B, 66, 86, 104 is sent to a control circuit (ECU) (not shown). The control circuit controls the opening and closing of each of the fuel cutoff valves 16A, 16B, 64, 68, 72, 84, 86, and 92 based on this data.

  Next, the operation of the gaseous fuel supply device 12 of this embodiment will be described.

  In the normal state, the fuel cutoff valves 16A and 16B are both opened, and fuel is delivered from both the fuel tanks 14A and 14B. In the normal state, the fuel cutoff valves 64, 68, 84, 88 are opened, and the fuel cutoff valves 72, 92 are closed. Therefore, the fuel sent from the fuel tanks 14A and 14B passes through the fuel supply main pipes 42 and 46, and is further supplied to the engine 20 through the fuel supply pipe 50.

  At this time, even if the fuel supply sub-pipe 44 is damaged, the check valves 62 and 74 can prevent inadvertent wrapping of fuel from the fuel supply main pipe 42 to the fuel supply sub-pipe 44. Similarly, even if the fuel supply sub-pipe 48 is damaged, the check valves 82 and 94 can prevent inadvertent wrapping of fuel from the fuel supply main pipe 46 to the fuel supply sub-pipe 48.

  Here, in the gaseous fuel supply device 12 of the present embodiment, a pressure drop has occurred due to damage (for example, complete breakage) or the like in either the fuel supply main pipe 46 or the fuel supply sub pipe 48 of the second fuel supply unit 26. In this case, it is possible to identify whether the cause portion is the fuel supply main pipe 46 or the fuel supply sub pipe 48 from the pressure drop behavior of the pressure sensor 86. That is, when a pressure drop occurs in the fuel supply main pipe 46, the pressure sensor 86 is provided in the fuel supply main pipe 46, so that the amount of pressure drop per unit time increases (abrupt pressure drop occurs). . On the other hand, when a pressure drop occurs in the fuel supply sub-pipe 48, the check valves 82 and 94 prevent the fuel from flowing from the fuel supply main pipe 46 to the fuel supply sub-pipe 48. The main pipe 46 is not directly affected by this. In the fuel supply main pipe 46, a pressure drop corresponding to the amount consumed by the engine 20 occurs, so that the pressure drop amount per unit time detected by the pressure sensor 86 is relatively small (a slow pressure drop is present). Occur). Therefore, it is possible to specify which portion of the pressure drop is the fuel supply main pipe 46 or the fuel supply sub pipe 48 based on the pressure drop amount per unit time detected by the pressure sensor 86.

  In the first fuel supply unit 24 as well, when the pressure drop amount per unit time detected by the pressure sensor 66 is relatively large, the portion of the pressure drop is the fuel supply main pipe 42. When it is relatively small, it can be determined that the fuel supply sub-pipe 44 is provided.

  Next, in consideration of a case where a sudden pressure drop occurs due to damage or the like in either the first fuel supply unit 24 or the second fuel supply unit 26, the gaseous fuel supply device 12 of the present embodiment uses the first fuel supply unit 24. It can be specified from the behavior of the pressure drop at each pressure sensor whether the pressure drop occurs in the supply unit 24 or the second fuel supply unit 26.

  Here, the fuel supply main pipes 42 and 46 are used to supply fuel to the engine 20, but either or both of these are replaced with the corresponding fuel supply sub pipes 44 and 48. The same applies to the case where there is.

  For example, assume that a portion L1 shown in FIG. In this case, in the pressure sensors 86 and 104 on the downstream side of the portion L1, the amount of pressure drop per unit time is increased compared to the pressure sensors 84 and 66 on the upstream side. On the other hand, for example, when the part L2 is the cause of the pressure drop, the pressure sensor 104, 86, 66 on the downstream side increases the pressure drop amount per unit time. That is, the amount of pressure drop per unit time is greater on the downstream side of the cause of the pressure drop than on the upstream side. In addition, when there are a plurality of pressure sensors downstream from the cause of the pressure drop, the pressure drop amount per unit time increases in the plurality of pressure sensors, but the fuel tank fuel tank 14A, It can be specified that there is a cause for the pressure drop between the most downstream pressure sensors among the pressure sensors that are upstream of the pressure sensor close to 14B and have a small amount of pressure drop per unit time. In this way, it is possible to specify which of the fuel supply main pipes 42 and 46 is the cause of the pressure drop.

  Moreover, in the gaseous fuel supply apparatus 12 of this embodiment, even if it is a case where a pressure drop generate | occur | produces in either of the fuel supply main piping 42 and 46 as mentioned above, the fuel supply to the engine 20 can be continued. it can. Here, as an example, it is assumed that a pressure drop occurs in the fuel supply main pipe 46 of the second fuel supply unit 26. Since this pressure drop is detected by the pressure sensor 86, the control circuit (not shown) closes the fuel cutoff valves 84 and 88 and opens the fuel cutoff valve 92. As a result, the second fuel supply unit 26 can continue to supply fuel using the fuel supply sub-pipe 48 instead of the fuel supply main pipe 46 in which the pressure drop has occurred. Moreover, in the fuel supply main pipe 46, both the upstream fuel cutoff valve 84 and the downstream fuel cutoff valve 88 of the pressure sensor 86 are closed, so that the fuel in the fuel supply sub pipe 48 is inadvertently supplied with fuel. It is possible to prevent the main pipe 46 from going around.

  In the first fuel supply unit 24 as well, when a pressure drop occurs in the fuel supply main pipe 42, the fuel cutoff valves 64 and 68 are closed and the fuel cutoff valve 72 is opened. As a result, the first fuel supply unit 24 can continue to supply fuel using the fuel supply sub-pipe 44 instead of the fuel supply main pipe 42 in which the pressure drop has occurred. Further, since both the fuel cutoff valves 64 and 68 are closed, it is possible to prevent the fuel in the fuel supply sub-pipe 44 from inadvertently entering the fuel supply main pipe 42.

  Thus, in the gaseous fuel supply device 12 of the present embodiment, the fuel supply main pipe and the fuel supply sub pipe are arranged in parallel, and even if a pressure drop occurs in the fuel supply main pipe used for fuel supply, By switching to the fuel supply sub-pipe, the fuel supply to the engine 20 can be continued.

  Moreover, in the gaseous fuel supply device 12 of the present embodiment, even when a pressure drop occurs in the state where the fuel supply sub-pipes 44 and 48 are used in this way, the pressure drop by each pressure sensor is detected as a part of the pressure drop. It is possible to specify from the behavior.

  For example, in a state where the fuel supply sub-pipe 48 and the fuel supply main pipe 42 are used instead of the fuel supply main pipe 46, the part L3 is assumed to be the cause of the pressure drop. In this case, the check valves 82 and 94 prevent the fuel from flowing from the fuel supply main pipe 46 to the fuel supply sub pipe 48, and there is no pressure drop per unit time detected by the pressure sensor 86. Or very little. That is, in the fuel supply main pipe 46 paired with the part L3, the pressure drop is extremely small. On the other hand, on the upstream side of the part L3, for example, the pressure drop per unit time detected by the pressure sensors 66, 52A, 52B is not particularly large because it is upstream of the part L3. Compared with the pressure drop per unit time detected by the pressure sensor 86, the pressure drop is relatively large.

  As described above, there is a pressure sensor having a relatively large pressure drop per unit time in a state where the fuel supply sub-pipe 48 and the fuel supply main pipe 42 are used instead of the fuel supply main pipe 46. In this case, it can be specified that there is a part that causes the pressure drop in the pipe paired with the pressure sensor that has a small pressure drop amount per unit time (or no pressure drop).

  There may be a state in which the fuel supply sub-pipe 44 and the fuel supply main pipe 46 are used as pipes for supplying fuel to the engine. In this state, when the part L4 is the cause of the pressure drop, the check valves 62 and 74 prevent the fuel from flowing from the fuel supply main pipe 42 to the fuel supply sub pipe 44, and the pressure There is no or very little pressure drop per unit time detected by the sensor 66. On the other hand, the pressure drop amount per unit time detected by the pressure sensors 52A and 52B is relatively large, and the pressure drop amount per unit time detected by the pressure sensor 86 is further increased. Therefore, even in this case, it can be specified that there is a cause for the pressure drop in the pipe paired with the pressure sensor having a relatively small pressure drop (or no pressure drop).

  Further, in the gaseous fuel supply device 12 of the present embodiment, fuel can be continuously supplied to the engine 20 even when a pressure drop occurs due to damage or the like in any of the fuel delivery pipes 18A and 18B of the fuel delivery unit 22. . For example, when the pressure sensor 52A detects that a pressure drop has occurred in the fuel delivery pipe 18A, the fuel cutoff valve 16A is closed. At this time, the check valve 56A prevents the fuel from flowing from the fuel delivery pipe 16B to the fuel delivery pipe 16A. Therefore, it is possible to continue sending fuel from the fuel tank 14B via the fuel delivery pipe 18B. Note that the pressure sensors 52A and 52B may be arranged downstream of the position shown in FIG. 2, for example, in the vicinity of the fuel cutoff valves 16A and 16B.

  As can be seen from the above description, in the first embodiment, the fuel supply unit is divided into the first fuel supply unit 24 on the upstream side and the second fuel supply unit 26 on the downstream side, and these are arranged along the fuel supply path. Are arranged in series. Therefore, only the portion where the pressure drop has occurred can be repaired or necessary measures for the corresponding fuel supply main pipe (which may be a fuel supply sub pipe), so that the time and cost required for these can be reduced. From this point of view, a fuel supply unit having the same configuration as the first fuel supply unit 24 and the second fuel supply unit 26 may be provided between the second fuel supply unit 26 and the most downstream fuel supply unit 28.

  On the other hand, FIG. 2 shows a gaseous fuel supply device 112 having a configuration including only the first fuel supply unit 24 as a second embodiment of the present invention. In the second embodiment, only the second fuel supply unit 26 of the first embodiment is not provided, and the other components have the same configuration. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted. To do.

  Also in the gaseous fuel supply apparatus 112 of the second embodiment, when a pressure drop occurs in the fuel supply main pipe 42, the fuel cutoff valves 64 and 68 are closed and the fuel cutoff valve 72 is opened. Instead of the fuel supply main pipe 42, the fuel supply can be continued using the fuel supply sub pipe 44. Further, since both the fuel cutoff valves 64 and 68 are closed, it is possible to prevent the fuel in the fuel supply sub-pipe 44 from inadvertently entering the fuel supply main pipe 42.

  Further, since the second fuel supply unit 26 is not provided in the gaseous fuel supply device 112 of the second embodiment, the number of parts is reduced as a whole, and the structure is simplified.

In each embodiment, two fuel supply pipes arranged in parallel that constitute the fuel supply pipe set (the first fuel supply unit 24 and the second fuel supply unit 26) according to the present invention (the fuel supply main pipe and the fuel supply). Although the one provided with one auxiliary pipe) is given, the number of fuel supply pipes constituting the fuel supply pipe group may be three or more. However, in consideration of the frequency with which the pressure drop actually occurs in the fuel supply main pipe or the fuel supply sub pipe, one is often sufficient. As in each of the above-described embodiments, it is preferable that the fuel supply main pipe and the fuel supply sub-pipe are one in each fuel supply pipe set, because the structure can be simplified.
In addition, although the gaseous fuel supply apparatus of the structure provided with the check valves 74 and 94 was mentioned above, even if it is a structure without these check valves, it is materialized as the gaseous fuel supply apparatus of this invention.

It is a schematic block diagram which shows the gaseous fuel supply apparatus of 1st embodiment of this invention. It is a schematic block diagram which shows the gaseous fuel supply apparatus of 2nd embodiment of this invention.

Explanation of symbols

12 Gaseous fuel supply devices 14A, 14B Fuel tanks 16A, 16B Fuel shutoff valve (sending pipe shutoff valve)
18A, 18B Fuel delivery pipe 20 Engine 22 Fuel delivery part 24 First fuel supply part 26 Second fuel supply part 28 Most downstream fuel supply part 30 Fuel filling port 32 Fuel filling pipe 34 Connection part 36 Connection part 38 Connection part 42 Fuel supply Main piping 44 Fuel supply sub piping 46 Fuel supply main piping 48 Fuel supply sub piping 50 Fuel supply piping 52A, 52B Pressure sensor (feeding piping pressure sensor)
56A, 56B Check valve (second check valve)
62 Check valve (first check valve)
64 Fuel cutoff valve (first cutoff valve, switching means)
66 Pressure sensor (Main piping pressure sensor)
68 Fuel cutoff valve (second cutoff valve, switching means)
72 Fuel shut-off valve (third shut-off valve, switching means)
74 Check valve 82 Check valve (first check valve)
84 Fuel cutoff valve (first cutoff valve, switching means)
86 Pressure sensor (Main piping pressure sensor)
88 Fuel shut-off valve (second shut-off valve, switching means)
92 Fuel shut-off valve (third shut-off valve, switching means)
94 Check valve 102 Pressure reducing valve 104 Pressure sensor 112 Gaseous fuel supply device

Claims (6)

A fuel tank containing gaseous fuel;
A fuel supply main pipe capable of supplying the gaseous fuel accommodated in the fuel tank to the engine, and a fuel supply sub pipe arranged parallel to the fuel supply main pipe and capable of supplying the gaseous fuel accommodated in the fuel tank to the engine A parallel piping assembly composed of piping, and
A main pipe pressure sensor for detecting a pressure in the fuel supply main pipe;
Switching means for switching the pipe used for fuel supply to the engine from the fuel supply main pipe to the fuel supply sub pipe when the pressure in the fuel supply main pipe detected by the main pipe pressure sensor decreases;
A gaseous fuel supply device comprising:   2. The gaseous fuel supply device according to claim 1, wherein a plurality of the parallel pipe sets are provided in series between the fuel tank and the engine. The switching means is
A first cutoff valve disposed upstream of the main pipe pressure sensor in the fuel supply main pipe;
A second shut-off valve disposed downstream of the main pipe pressure sensor in the fuel supply main pipe;
A third shut-off valve disposed in the fuel supply sub-pipe;
The gaseous fuel supply device according to claim 1, wherein the gaseous fuel supply device is provided.   4. The first check valve for preventing a backflow of gaseous fuel from the downstream side to the upstream side is disposed in the fuel supply main pipe. 5. Gaseous fuel supply device. A plurality of the fuel tanks;
A fuel delivery pipe for delivering gaseous fuel from each of the plurality of fuel tanks to the most upstream parallel pipe set;
A delivery pipe pressure sensor provided in each of the fuel delivery pipes;
A delivery pipe shut-off valve disposed upstream of the delivery pipe pressure sensor in each of the fuel delivery pipes;
A second check valve that is arranged downstream of the delivery pipe pressure sensor in each of the fuel delivery pipes and prevents the backflow of gaseous fuel from the downstream side to the upstream side;
The gaseous fuel supply device according to any one of claims 1 to 4, wherein the gaseous fuel supply device is provided. 5. A pressure drop piping specifying method for specifying whether a pressure drop has occurred in either the fuel supply main pipe or the fuel supply sub pipe in the gaseous fuel supply apparatus according to claim 4,
When the pressure drop per unit time detected by the main pipe pressure sensor is larger than the set threshold value, a pressure drop occurs in the fuel supply main pipe, and when the pressure drop amount is smaller than the threshold value, the pressure drop occurs in the fuel supply sub pipe. A pressure drop piping identification method characterized by identifying occurrence.

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