JPH04262044A - Very low temperature fuel supply device - Google Patents

Abstract

PURPOSE:To keep the internal pressure of a cold insulation tank at a constant pressure without causing the reduction in the heat insulating performance of the cold insulation tank by selectively supplying very low temperature fuel vaporized in a fuel supply pipe into a fuel reservoir or a cold insulation tank. CONSTITUTION:A solenoid changeover valve 50 interposed between a fuel supply pipe 20 and a pressure-retaining pipe 40 is properly changed over on the basis of the pressure of LNG flowing in the fuel supply pipe 20, and the vaporized LNG is properly supplied into the inner tank 11 of a cold insulation tank 10, thereby the internal pressure of the cold insulation tank 10 is kept at a constant pressure.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic fuel supply system, and more particularly to a mechanism for controlling the internal pressure of a cold storage tank containing cryogenic fuel.

0002

2. Description of the Related Art FIG. 2 shows an automobile engine that uses liquefied natural gas, which is one of the cryogenic fuels, as fuel. A cryogenic fuel supply device A in this engine is equipped with the liquefied natural gas (hereinafter referred to as It is equipped with a cold storage tank B for accommodating LNG (referred to as LNG). The above cold storage tank B is LNG
an inner tank Ba in which the water is stored, and an outer tank Bb surrounding the inner tank Ba.
, and a casing Bc surrounding the outer tank Bb, and internal pressure is applied to the inner tank Ba. Further, the cold tank B is provided with a fuel supply pipe C, and the LNG in the liquid phase in the cold tank B is sent to the vaporizer D via the fuel supply pipe C due to the internal pressure of the cold tank B. , after being vaporized in this vaporizer D, regulator E, surge tank F
, and a fuel injector G into an intake manifold I connected to an engine body H. LNG by running the engine at high speed, etc.
When a large amount of LNG is consumed, the amount of liquid-phase LNG in the cold storage tank B decreases, and as a result, the internal pressure of the cold storage tank B decreases, making it difficult to supply an appropriate amount of fuel to the engine body H. becomes. Therefore, in the cold storage tank B,
The outer tank Bb and the casing B are guided out from the bottom of the inner tank Ba.
A pressure holding pipe J is provided that extends between the inner tank Ba and the inner tank Ba, and further passes through the outside of the casing Bc and faces the upper space of the inner tank Ba. When the on-off valve K installed in the pressure holding pipe J is opened, LNG in a liquid phase in the inner tank Ba flows into the pressure holding pipe J, and this LNG is transferred to the outer tank Bb and the casing Bc. During this period and while passing through the outside of the casing Bc, the gas vaporizes and becomes a gaseous state and is sent into the inner tank Ba. In the cold storage tank B where the internal pressure is applied, the pressure acting on the liquid phase LNG is greater than that of the gas phase LNG due to its own weight. The internal pressure of the cold storage tank B increases due to the pressure of the vaporized LNG fed into the tank. When a predetermined internal pressure is obtained, the on-off valve K is closed, and when the internal pressure of the cold storage tank B decreases again, the on-off valve K is closed.
will be opened. The internal pressure of the cold storage tank B is maintained substantially constant by the opening/closing operation of the on-off valve K.

0003

[Problems to be Solved by the Invention] Incidentally, the cold storage tank B in the conventional cryogenic fuel supply system described above has one location provided by the fuel supply pipe C and two locations provided by the pressure retention pipe J.
There are a total of three openings. Although current insulation technology for cold storage tanks is extremely advanced, it is difficult to completely prevent heat from entering through the openings provided in the cold storage tank. It is greatly influenced by the area of the opening. For this reason, the conventional cryogenic fuel supply apparatus described above, in which the cold storage tank is provided with as many as three openings, has the disadvantage of causing a significant drop in insulation performance. SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a cryogenic fuel supply device that can keep the internal pressure of a cold storage tank constant without causing a decrease in the insulation performance of the cold storage tank.

0004

[Means for Solving the Problems] Accordingly, in the present invention, a cold storage tank containing cryogenic fuel is provided with a fuel supply pipe that communicates with an object to be supplied with fuel, and a fuel supply pipe that is connected to the fuel supply pipe via a switching valve. Further, a pressure sensor is provided in the fuel supply pipe, and a control means for operating the switching valve based on the pressure value detected by the pressure sensor is provided, and the cryogenic fuel vaporized in the fuel supply pipe is provided with a control means for operating the switching valve based on the pressure value detected by the pressure sensor. The above object is achieved by configuring the fuel tank to be selectively supplied to the fuel supply object or the cold storage tank.

[0005]

[Function] According to the above structure, there are only two openings in the cold storage tank, one for the fuel supply pipe and one for the pressure retention pipe, which reduces the area of the part that causes heat intrusion. can be kept to a minimum.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be explained in detail below based on the drawings showing one embodiment. FIG. 1 shows an example in which the cryogenic fuel supply device according to the present invention is adopted as a fuel supply device for an automobile engine that uses liquefied natural gas as fuel.
This fuel supply device 1 includes a cold storage tank 10 for storing liquefied natural gas (hereinafter referred to as LNG).

The cold storage tank 10 includes an inner tank 11 for storing LNG 100 and an outer tank 12 surrounding the inner tank 11, and the space between the inner tank 11 and the outer tank 12 is insulated. The purpose is to maintain a vacuum, and furthermore, the inner tank 11
The outer tank 12 is housed inside the casing 13.

As clearly shown in FIG. 1, the cold storage tank 10
A fuel supply pipe 20 is attached to the inner tank 11, the outer tank 12, and the casing 13 so as to penetrate through them. One end 20a of the fuel supply pipe 20 is located at the bottom of the inner tank 11, and its opening is immersed in 100 liters of liquid-phase LNG stored in the inner tank 11.

The fuel supply pipe 20 is connected to the cold storage tank 1.
0 toward the engine body 30 as a fuel supplied body, and includes a vaporizer 21 and a regulator 22.
, and a surge tank 23 are interposed, and a plurality of fuel injectors 24 facing an intake manifold 31 connected to the engine main body 30 are connected to the surge tank 23.

[0010] The cold storage tank 10 also includes an inner tank 11.
, the outer tank 12 , and the casing 13 . This pressure holding pipe 4
One end 40a of 0 is located in the upper part of the inner tank 11,
The opening is open to the gas phase L stored in the inner tank 11.
I am facing NG100g.

The pressure holding pipe 40 extends to the downstream portion of the vaporizer 21 in the fuel supply pipe 20, and is connected to the fuel supply pipe 20 and the pressure holding pipe 40.
and are connected to each other via an electromagnetic switching valve 50.

Further, a pressure sensor 60 is installed in the downstream region of the vaporizer 21 in the fuel supply pipe 20, and the electromagnetic switching valve 50 is controlled by a control device 70 based on pressure information from the pressure sensor 60, as will be described later. The switching operation is performed as appropriate by the command signal.

[0013] The fuel supply pipe 20 and the pressure holding pipe 40 are provided with LNG 1 to the cold storage tank 10, respectively.
Connection coupling 25 used when supplying 00
A manual on-off valve 26, a connection coupling 41, a manual on-off valve 42, and a relief valve 43 are provided.

[0014] In the following, the cryogenic fuel supply device 1 described above will be described.
The operation for controlling the internal pressure of the cold storage tank 10 will be explained. Immediately after LNG is supplied to the cold storage tank 10, etc.
When the internal pressure of the LNG tank 10 is sufficiently high, the fuel supply pipe side port of the electromagnetic switching valve 50 is open, while the pressure maintaining pipe side port of the electromagnetic switching valve 50 is closed. Therefore, 100 liters of LNG in a liquid phase in the cold storage tank 10 is sent to the vaporizer 21 via the fuel supply pipe 20 due to the internal pressure of the cold storage tank 10 and is vaporized, and then is passed through the electromagnetic switching valve 5 as shown by arrow a.
0, and then regulator 22 and surge tank 2.
3 to each fuel injector 24, and from the fuel injector 24 to the engine main body 3.
The fuel is injected into the intake manifold 31 connected to 0.

On the other hand, due to engine operation, LNG100
is consumed, and the LN in the liquid phase in the cold storage tank 10
Due to the decrease in G100l, the internal pressure of the cold storage tank 10 decreases, and the fuel supply pipe 2 is detected by the pressure sensor 60.
When the pressure within 0 falls below 8 kg per square cm, the control device 10
closes the fuel supply pipe side port of the electromagnetic switching valve 50, while opening the pressure holding pipe side port of the electromagnetic switching valve 50.

[0016] As a result, the vaporized LNG sent from the cold storage tank 10 to the vaporizer 21 via the fuel supply pipe 20 passes through the electromagnetic switching valve 50 as shown by arrow b, passes through the pressure holding pipe 40, and is cooled. It is sent into the inner tank 11 of the tank 10.

[0017] As mentioned earlier, in the cold storage tank 10, 100 liters of LNG in a liquid phase has a higher pressure than 100 g of LNG in a gas phase by its own weight. Cold storage tank 10 via 40
The internal pressure of the cold storage tank 10 increases due to the pressure of the vaporized LNG fed into the inner tank 11 of the tank.

When the internal pressure in the cold storage tank 10 increases and the pressure in the fuel supply pipe 20 detected by the pressure sensor 60 becomes 8 kg or more per square cm,
Based on the pressure information from the pressure sensor 60, the control device 10 opens the fuel supply pipe side port of the electromagnetic switching valve 50, and closes the pressure holding pipe side port of the electromagnetic switching valve 50, thereby allowing the fuel to flow into the cold storage tank 10. The supply of vaporized LNG will be stopped.

As described above, in the cryogenic fuel supply system 1, the electromagnetic switching valve interposed between the fuel supply pipe 20 and the pressure holding pipe 40 is operated based on the pressure of LNG flowing through the fuel supply pipe 20. 50 as appropriate.
By appropriately supplying vaporized LNG into the inner tank 11 of the cold storage tank 10, the internal pressure of the cold storage tank 10 is maintained constant.

It should be noted that the pressure value inside the fuel supply pipe 20 when the electromagnetic switching valve 50 is operated is not limited to the value shown in this embodiment;
Needless to say, it can be appropriately set based on various conditions such as the size of the cold storage tank 10 and the structure of the cold storage tank 10. Further, in the above embodiment, the electromagnetic switching valve that connects the fuel supply pipe and the pressure holding pipe is provided in the downstream region of the vaporizer in the fuel supply pipe, but even if the electromagnetic switching valve is provided in the upstream region of the vaporizer, Of course, the object of the present invention can be fully achieved. Furthermore, the cryogenic fuel supply device according to the present invention is not only applicable to a fuel supply device for an automobile engine that uses LNG as fuel as shown in the embodiment, but also to a motorcycle engine that is operated using cryogenic fuel. It goes without saying that it can be widely adopted as a cryogenic fuel supply system for various engines such as outboard engines or stationary engines, and the cryogenic fuel supply system according to the present invention is suitable for liquefaction. It goes without saying that it can be effectively applied as a device for supplying not only natural gas but also various cryogenic fuels such as liquefied hydrogen.

[0021]

As described in detail above, according to the cryogenic fuel supply device according to the present invention, the cold storage tank containing the cryogenic fuel is provided with a fuel supply pipe communicating with the object to be supplied with fuel, and A pressure holding pipe connected to the fuel supply pipe via a switching valve is provided, and a pressure sensor is further provided in the fuel supply pipe, and a control means is provided to operate the switching valve based on the pressure value detected by the pressure sensor. established,
The internal pressure of the cold storage tank is kept constant by selectively supplying the vaporized cryogenic fuel to the fuel supply object or the cold storage tank.

[0022] According to this configuration, the number of openings is reduced to two in total, one by the fuel supply pipe and one by the pressure holding pipe, instead of the three openings provided in the cold storage tank of the conventional cryogenic fuel supply system. Therefore, compared to conventional cryogenic fuel supply systems, the area of the part that causes heat intrusion can be kept as small as possible. It becomes possible to maintain the internal pressure of the tank constant.

[Brief explanation of the drawing]

[Fig. 1] Conceptual overall diagram of an engine employing a cryogenic fuel supply device according to the present invention

[Figure 2] Conceptual overall diagram of an engine that uses a conventional cryogenic fuel supply system

[Explanation of symbols]

1...Cryogenic fuel supply device 10...Cold tank 20...Fuel supply pipe 21...Vaporizer 30...Engine body (fuel supplied object) 40...Pressure pipe 50...Solenoid switching valve 60...Pressure sensor 70...control device 100...Liquefied natural gas (cryogenic fuel)

Claims (1)

[Claims] Claim 1: Provided in a cold storage tank for storing cryogenic fuel and communicated with a fuel supply target, the cryogenic fuel in a liquid phase in the cold storage tank is supplied to the fuel supply target in a vaporized state. a pressure holding pipe that is provided in the cold storage tank and connected to the fuel supply pipe via a switching valve and that supplies vaporized cryogenic fuel to the cold storage tank; A control means for operating the switching valve to supply the vaporized cryogenic fuel to the fuel supply object or the cold storage tank based on pressure information from the provided pressure sensor. cryogenic fuel supply equipment.