JP2003206810A - Liquefied gas supplying device for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquefied gas supplying device for an automobile that is easily maintained and realizes stable fuel supply without causing run out of fuel. <P>SOLUTION: The liquefied gas supplying device A1 for the automobile comprises gas phase piping 5 disposed between a top wall surface 1a of a storage tank 1 and a top wall surface 4a of a fuel trap 4 and liquid phase piping 6 for communicating a liquid phase part y1 of the storage tank 1 with a liquid phase part y2 of the fuel trap 4, between the fuel trap 4 including a force feed pump 3 and the storage tank 1. The fuel trap 4 is provided with return piping 7 for returning residual liquefied gas in an engine e to the fuel trap 4. The fuel trap 4 is disposed out of the storage tank 1, thereby facilitating repairing work of the force feed pump 3. The fuel trap 4 is provided with the return piping 7, thereby preventing a state where a liquefied gas amount in the fuel trap 4 does not reach an amount required for suction. The gas phase piping 5 eliminates high pressure in the fuel trap 4. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquefied gas supply device for a vehicle for supplying a liquefied gas used as a fuel for a vehicle from a storage tank mounted mainly in a vehicle such as a taxi to an engine. .

[0002]

2. Description of the Related Art Conventionally, liquefied gas has been used as fuel for automobiles, and various liquefied gas supply devices for automobiles which supply an engine from a storage tank mounted on an automobile such as a taxi have been proposed. As shown in FIG. 5, for example, as shown in FIG. 5, the liquefied gas supply device B1 for an automobile has a situation in which the fuel is biased due to an inclination of the automobile or the like, and the fuel liquid level temporarily lowers below the suction port of the pump (so-called. A sub-tank b is provided in the storage tank a to prevent the fuel from running out. A pressure pump c is provided in the sub tank b, and a return pipe d for flowing into the sub tank b in the storage tank a is provided in order to enable reuse of the liquefied gas not consumed by the engine e. The arrangement is common. In such a configuration, the liquefied gas in the storage tank a supplied from the gas station or the like is supplied into the sub tank b through the communication hole f with a check valve or the like, and is then sent to the engine e by the pressure pump c. It will be.

Although not a general structure, as a gasoline supply device B2 for an automobile for supplying gasoline from a storage tank to an engine, as shown in FIG. 6, a pressure feed pump c is provided outside and below the storage tank a. There is known a configuration in which gasoline is supplied to a pressure pump c through a pump supply pipe g, which is arranged at a position.

[0004]

However, the liquefied gas supply device for an automobile (see FIG. 5) in which the sub tank and the pressure feed pump are arranged in the storage tank described above has the following problems. (1) When the pressure feed pump fails due to friction between its parts, it is necessary to remove the pressure feed pump from the storage tank for repair and replacement. Here, since the liquefied gas is flammable, this work needs to be performed after the strict exhaust gas work for completely discharging the liquefied gas, which requires a lot of labor. Since the liquefied gas has poor lubricity and the above-mentioned failures often occur, it is a serious problem in terms of work efficiency to be forced to perform the work each time.
A means for collectively exchanging the storage tank together with the pressure pump can be proposed, but it is very expensive and not practical. (2) When a defect (such as rust) occurs in the sub tank and it is necessary to replace the sub tank, it is necessary to take out the sub tank from the storage tank. This work also needs to be performed after the above-mentioned strict exhaust gas work, which is very labor intensive. Further, in order to avoid this troublesome work, it may be proposed to collectively replace the storage tank together with the sub tank, but it is not practical from the viewpoint of high cost. (3) When the storage tank is arranged in the trunk of the automobile (position immediately behind the rear seat), vibration or driving sound generated by driving the pressure pump resonates with the storage tank,
There is a problem of echoing inside the car. (4) Since the sub-tank and the pressure feed pump have to be installed in the limited space inside the storage tank that requires airtightness, the structure of the supply device becomes complicated and manufacturing becomes difficult. Also, since the weight of the storage tank increases,
Workability at the time of manufacturing and mounting on a vehicle also deteriorates.

On the other hand, from the viewpoint of improving the maintainability of the pressure pump, a gasoline supply device for an automobile (see FIG. 6) provided outside the storage tank without the pressure pump being incorporated in the storage tank is applied to the liquefied gas. It may be suggested to do so. However, it is not practical because of the following problems. That is, when liquefied gas having a boiling point significantly lower than that of gasoline is applied to the structure in which the fuel is directly supplied to the pressure-feeding pump through the pipe in this way, decompression boiling easily occurs near the suction port of the pressure-feeding pump, and cavitation is often generated. Expected to occur. On the other hand, although a means for reducing the suction force of the pressure pump to prevent cavitation can be proposed, the fuel supply to the engine becomes insufficient. Therefore, these problems resulting from the physical properties of the liquefied gas have been a major impediment to practical use.

Therefore, an object of the present invention is to provide a liquefied gas supply device for an automobile which can solve the above-mentioned problems.

[0007]

SUMMARY OF THE INVENTION The present invention comprises a storage tank for storing liquefied gas, and a fuel trap disposed outside the storage tank and having a pressure pump for pumping liquefied gas to an engine. The liquid liquefied gas supply device for an automobile is characterized in that the liquid phase portions of the storage tank and the fuel trap are connected to each other by liquid phase piping.

As described above, the fuel trap having the pump for pumping the liquefied gas can be temporarily stored outside the storage tank, so that if the pump fails, the fuel trap Repairs and replacements are possible simply by removing this pump from the trap. here,
Work to remove the pressure pump from the fuel trap (the present invention)
And the work of removing the pressure pump from the storage tank (conventional structure), which is more advantageous in terms of work efficiency becomes a problem, but the volume of the fuel trap is extremely smaller than that of the storage tank ( It is sufficient if at least a volume capable of containing the pressure feed pump is secured.) Since the exhaust gas operation of the liquefied gas described above can be completed in a short time, the configuration according to the present invention is significantly advantageous. For example, as a preferred embodiment of the present invention, the storage tank is 100 L,
A configuration in which the fuel trap is 0.5 L can be exemplified. It should be noted that, in the present invention, since the sub-tank is not arranged in the storage tank, it is clear that the sub-tank need not be repaired or replaced.

Further, according to this structure, a so-called submerged pump can be used, so that there is no problem that cavitation occurs near the suction port of the pressure pump.

Further, the ceiling walls of the storage tank and the fuel trap are communicated with each other by vapor-phase pipes, and the pressure generated by the liquid level difference between the liquid phase portion of the storage tank and the liquid phase portion of the fuel trap causes the storage tank to come out of the storage tank. A configuration is proposed in which liquefied gas is sent to the fuel trap. In this manner, the gas-phase pipes are arranged so that the storage tank and the fuel trap communicate with each other to equalize the internal pressures of each other and to send the liquefied gas to the fuel trap by the pressure generated by the liquid level difference. Thus, the liquid level of the liquefied gas in the fuel trap is maintained at the liquid level of the liquefied gas in the storage tank. The top wall portion on which the vapor-phase pipe is arranged also includes the top wall surfaces of the storage tank and the fuel trap and side surface portions near the top wall surface. By arranging the vapor phase pipes on the ceiling wall portion, respectively, the volumes of the storage tank and the fuel trap can be effectively used, and the internal pressures can be equalized.

Here, as a structure in which the liquefied gas is sent from the storage tank to the fuel trap by the pressure generated by the liquid level difference between the liquid phase portion of the storage tank and the liquid phase portion of the fuel trap, the arrangement position of the fuel trap is stored. It is desirable to arrange it at a sufficiently lower position relative to the tank. With such a configuration, the liquefied gas in the storage tank can be smoothly supplied into the fuel trap. It should be noted that the present invention does not exclude a configuration in which the position where the fuel trap is disposed is not sufficiently lower than the storage tank.
For example, the bottom of the storage tank and the bottom of the fuel trap may be relatively arranged at substantially the same height (so-called parallel system).

Further, in the above structure, the excess liquefied gas not consumed by the engine is returned by the return pipe.
A configuration for returning to the fuel trap is proposed. By replacing excess liquefied gas to the storage tank (conventional configuration) instead of returning excess liquefied gas to the fuel trap, the amount of liquefied gas in the fuel trap is less than the amount required for suction. It becomes difficult to cause the state that there is no such gas, and the liquefied gas can be stably supplied to the engine.
Further, even if the vehicle tilts due to running and the liquefied gas in the fuel trap vibrates violently with it, so-called fuel shortage is unlikely to occur.

[0013]

Embodiments of the present invention will be described with reference to the accompanying drawings. As shown in FIG. 1 or 2, the vehicle liquefied gas supply device A1 according to the present invention includes a storage tank 1 for storing liquefied gas and a fuel trap 4 in which a pressure pump 3 is provided. Here, the liquefied gas supply device A1 for automobiles shown in FIG. 1 shows a state when the pressure feed pump 3 is stopped, while FIG. 2 shows a time when the pressure feed pump 3 is driven.

The fuel trap 4 is arranged outside the storage tank 1. Here, the general capacity of the storage tank 1 is about 100 L, and the capacity of the fuel trap 4 is about 0.
5L is preferred. Thus, the capacity of the fuel trap 4 is about 1/200 of the capacity of the storage tank 1.
The capacity of the fuel trap 4 is at least the pressure pump 3
Any capacity may be included.

Between the storage tank 1 and the fuel trap 4, a liquid phase pipe 6 for connecting the liquid phase portion y1 of the storage tank 1 and the liquid phase portion y2 of the fuel trap 4 is arranged. Further, a vapor phase pipe 5 that connects the storage tank 1 and the top wall of the fuel trap 4 is provided. In addition, in this embodiment, as shown in FIG.
Are disposed on the top wall surface 1a of the storage tank 1 and the top wall surface 4a of the fuel trap 4. Here, the disposition position of the vapor phase pipe 5 is not limited to the above-described ceiling wall surfaces 1a and 4a, but may be disposed at a side surface portion near the ceiling wall surfaces 1a and 4a. That is, as the top wall portion, in addition to the top wall surfaces 1a and 4a of the storage tank 1 and the fuel trap 4,
It also includes the side surface portions near the top wall surfaces 1a and 4a.
With this configuration, the gas phase portion x of the storage tank 1
1 and the gas phase portion x2 of the fuel trap 4 can be suitably communicated with each other.

Here, depending on the relative positional relationship between the storage tank 1 and the fuel trap 4, the amount of liquefied gas in the storage tank 1, the driving condition of the pressure feed pump 3, and the like, the gas connected to the fuel trap 4 may be used. When the liquefied gas partially enters the vapor phase pipe 5 near the pipe port of the phase pipe 5 (for example,
1). In such a case, the upper part of the liquefied gas is used as the gas phase part x2 of the fuel trap 4. As described above, a configuration in which the vapor phase portion x2 of the fuel trap 4 is present in the vapor phase pipe 5 is also included in the present invention. This is because the gas phase pipe 5 according to the present invention
Is provided to equalize the internal pressure of the storage tank 1 and the internal pressure of the fuel trap 4.

On the other hand, between the fuel trap 4 and the engine e, a pressure feed pipe 8 for guiding the liquefied gas pressure-fed from the pressure feed pump 3 to the engine e, and among the liquefied gas pressure-fed from the pressure feed pump 3, the engine Return pipe 7 for resending the excess liquefied gas not consumed in e into the fuel trap 4.
And are provided.

The liquefied gas supply device A1 for automobiles having these configurations is loaded on the automobile (not shown).

Here, regarding the positional relationship between the storage tank 1 and the fuel trap 4, the structure in which the fuel trap 4 is sufficiently lower than the storage tank 1 (see FIGS. 1 and 2) is smoothly liquefied. Although it is suitable for supplying gas, as shown in FIG. 3, a liquefied gas supply device A2 for automobiles in which the bottom surfaces of the storage tank 1 and the fuel trap 4 are at substantially the same height may be used. The liquefied gas supply device A2 for automobiles shown in FIG. 3 shows a state where the pressure pump 3 is stopped.

Further, there are cases where the vapor phase pipe 5 cannot be arranged so as to pass above the storage tank 1 or the fuel trap 4 because of the limited layout design. In such a case, as shown in FIG. 4A, the substantially U-shaped gas-phase pipe 5
liquefied gas supply device A3 for an automobile, in which a is arranged so as to pass below the bottom of each of the storage tank 1 or the fuel trap 4.
Is proposed. Further, as shown in FIG.
A character-shaped gas-phase pipe 5b may be arranged so as to extend between the storage tank 1 and the fuel trap 4. In addition, the liquefied gas supply device A3 for automobiles shown in FIG.
Indicates that the pressure feed pump 3 is stopped.

In the above-mentioned structure, the liquefied gas in the storage tank 1 replenished at the gas stand or the like flows into the fuel trap 4 through the liquid phase pipe 6. When the engine e starts driving (that is, the pressure pump 3 starts driving), the liquefied gas in the fuel trap 4 is sucked by the pressure pump 3 in the fuel trap 4 and supplied to the engine e through the pressure pipe 8. It
Then, the liquefied gas that has been pressure-fed serves as fuel and the engine e is continuously driven, so that the automobile runs. Then, of the liquefied gas supplied to the engine e, the unconsumed liquefied gas is retransmitted to the fuel trap 4 through the return pipe 7.

By the way, the storage tank 1 and the fuel trap 4
Is communicated with the liquid-phase pipe 6 and the gas-phase pipes 5, 5a, 5b, and is caused by the pressure generated by the liquid level difference between the liquid-phase part y1 of the storage tank 1 and the liquid-phase part y2 of the fuel trap 4. Then, the liquefied gas in the storage tank 1 moves to the fuel trap 4, and the height of the liquid level h1 of the liquefied gas in the storage tank 1 and the height of the liquid level h2 of the liquefied gas in the fuel trap 4 are relatively high. Try to be equal. Therefore, when the pressure feed pump 3 is stopped, each liquid level h1, h2
Have the same height (see FIG. 1, FIG. 3, or FIG. 4).

However, when the pressure pump 3 is driven,
The liquefied gas in the fuel trap 4 is consumed, and the fuel supply due to the pressure generated by the above-mentioned liquid level difference cannot keep up with the fuel supply. Therefore, the level h2 of the liquid level in the fuel trap 4 is substantially equal to that of the liquid level in the storage tank 1. It is relatively lower than the height of the level h1 (see FIG. 2). However, even in such a case, since the excess liquefied gas not consumed by the engine e is retransmitted to the fuel trap 4 by the return pipe 7, the amount of liquefied gas in the fuel trap 4 is less than the amount required for suction. The situation that there is no occurrence is less likely to occur, and the engine e
The liquefied gas can be stably supplied to. Further, even if the liquefied gas violently shakes in the fuel trap 4 due to deceleration of the vehicle or traveling on a slope (when the engine e is driven), the problem of so-called fuel shortage is unlikely to occur. The amount of surplus liquefied gas retransmitted to the fuel trap 4 is about 80% to 90% of the amount of liquefied gas supplied from the pressure feed pump 3 to the engine e, so that the above problem can be preferably solved. it can.

Since the surplus liquefied gas has passed through the engine e, the surplus liquefied gas has a higher temperature than the liquefied gas contained in the storage tank 1 or the like. When such an excess liquefied gas flows into the fuel trap 4 via the return pipe 7, the temperature and pressure inside the fuel trap 4 are increased, but the gas-phase pipes 5, 5a, 5b communicating with the storage tank 1 are formed. By providing, the internal pressure of the fuel trap 4 changes in the direction of pressure reduction (that is, the same pressure as the storage tank 1), and a thermodynamic equilibrium state is achieved. Therefore, the problem of a decrease in the fuel supply capacity from the storage tank 1 caused by the increase in the internal pressure of the fuel trap 4 does not occur. Furthermore, storage tank 1
Since only the internal pressure of 1 does not become extremely high, even when the liquefied gas is supplied into the storage tank 1 at a gas stand or the like, it can be supplied smoothly.

By the way, the fuel trap 4 is attached to the storage tank 1.
Liquefied gas supply device A for automobiles that can be arranged at a lower position
When loading 1 into a passenger car such as a taxi,
It is preferable that the storage tank 1 is arranged in the trunk room and the fuel trap 4 is arranged under the body. By adopting such an arrangement design, it is possible to avoid vibrations or the like generated by the driving of the pressure pump 3 from affecting the inside of the vehicle and impairing comfort. Further, since the storage tank 1 and the fuel trap 4 can be arranged with a sufficient height difference, the storage tank 1 and the fuel trap 4 are stabilized by the pressure generated by the liquid level difference between the liquid phase portion y1 of the storage tank 1 and the liquid phase portion y2 of the fuel trap 4. As a result, liquefied gas can be supplied.

[0026]

The liquefied gas supply system for automobiles of the present invention comprises:
As described above, since the fuel trap capable of temporarily storing the liquefied gas having the pressure pump inside the storage tank is provided, even if the pressure pump fails, the fuel pump can be used as a fuel trap. Just take it out of the trap,
It is much simpler than the work of taking out from the storage tank. In addition, the cost of repair will not increase.

Further, since the degree of freedom in the layout design is increased, the layout can be such that the vibration due to the driving of the pressure pump does not resonate in the vehicle. Further, since it is not necessary to integrate the entire device, the manufacturing process is not complicated. Furthermore, the deterioration of the mounting work due to the increase in the weight of the storage tank is eliminated. In the present invention, since the sub-tank arranged in the storage tank having the conventional configuration is unnecessary, complicated work such as repair and replacement of the sub-tank can be eliminated.

Further, since the pressure-feeding pump is built in the fuel trap, the pressure-feeding pump is sufficiently immersed in the liquefied gas, so that so-called fuel shortage and cavitation in the vicinity of the suction port of the pressure-feeding pump hardly occur, and stable. Fuel can be supplied to the engine.

Further, in the case where the gas phase pipe is arranged between the storage tank and the fuel trap and the liquefied gas is supplied by the liquid level difference, the internal pressures of the storage tank and the fuel trap can be made equal, The liquid level of the liquefied gas in the trap can be maintained at the liquid level of the liquefied gas in the storage tank. Therefore, it is possible to avoid problems such as a decrease in the supply capacity of the liquefied gas from the storage tank and so-called fuel exhaustion.

Further, since the excess liquefied gas is retransmitted into the fuel trap through the return pipe and the liquefied gas is returned to the fuel trap, the amount of liquefied gas in the fuel trap is required for suction. The condition that the amount is less than that is less likely to occur, and the liquefied gas can be stably supplied to the engine. Further, even if the vehicle tilts due to running and the liquefied gas in the fuel trap vibrates violently with it, the fuel is less likely to run out. There is a problem that the high temperature excess liquefied gas causes the internal pressure of the fuel trap to be high and hinders the fuel supply from the storage tank.However, the gas phase piping is installed to increase the internal pressure of the storage tank and the fuel trap. Since they are made equal, the above problem does not occur.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an automobile liquefied gas supply device A1 when a pressure feed pump 3 is stopped.

FIG. 2 is a schematic diagram showing a configuration of a liquefied gas supply device A1 for an automobile when a pressure pump 3 is driven.

FIG. 3 is a liquefied gas supply device A2 for automobiles according to another embodiment.
It is a schematic diagram which shows the structure of.

FIG. 4A is a schematic diagram showing a configuration of an automobile liquefied gas supply device A3 including a substantially U-shaped vapor phase pipe 5a passing below the storage tank 1 and the like, and B is a storage tank 1 and a fuel. Almost U which is arranged so as to be passed between the trap 4 and
It is a schematic diagram which shows the structure of the liquefied gas supply apparatus A3 for motor vehicles provided with the V-shaped vapor phase piping 5b.

FIG. 5 is a schematic diagram showing a configuration of a conventional vehicle liquefied gas supply device B1.

FIG. 6 is a schematic diagram showing a structure of a conventional gasoline supply device for a vehicle B2.

[Explanation of symbols]

A1-A3 Liquefied gas supply device for automobiles e engine 1 storage tank 3 pressure pump 4 Fuel trap 5,5a, 5b Gas phase piping 6 Liquid phase piping 7 Return piping 8 pumping piping x1, x2 gas phase part y1, y2 liquid phase part

Claims (3)

[Claims] 1. A storage tank for storing liquefied gas, and a fuel trap, which is arranged outside the storage tank and has a pump for pumping the liquefied gas to the engine. The storage tank and the fuel trap respectively. A liquefied gas supply device for an automobile, characterized in that the liquid phase part of the is connected by a liquid phase pipe. 2. The storage tank and the top wall of the fuel trap are connected to each other by a vapor phase pipe, and the storage tank is separated from the storage tank by a pressure generated by a liquid level difference between the liquid phase portion of the storage tank and the liquid phase portion of the fuel trap. The liquefied gas supply device for an automobile according to claim 1, wherein the liquefied gas is sent to the fuel trap. 3. The liquefied gas supply device for an automobile according to claim 2, wherein excess liquefied gas not consumed by the engine is returned to the fuel trap through a return pipe.