JPH0882251A - Liquefied gas fuel supplying device - Google Patents

Abstract

PURPOSE: To realize a liquefied gas fuel supplying device which dispenses with the attachment and detachment of an additional device and can effectively utilize an excessive gas phase gas. CONSTITUTION: This device has a discharge passage 3 for discharging an excessive gas phase gas 1b from a fuel tank 1, a catalytic combusting means 4 provided on the terminal end of the discharge passage 3, a discharge control valve 5 for performing the communication and interruption between the fuel tank 1 and the catalytic combusting means 4, a buffer tank 8 provided between the discharge control valve 5 and a first relief valve through a branched part 7, and a reliquefying device 9 allowed to communicate with the buffer tank 8 to liquefy the excessive gas phase gas 1b. Thus, the excessive gas phase gas 1b is decomposed into carbon dioxide and steam by the catalytic combusting means 4 to prevent air pollution. An additional device for using the excessive gas phase gas 1b in a domestic gas equipment is dispensed with.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquefied gas fuel supply system for supplying a liquefied gas fuel such as natural gas to an internal combustion engine mounted on a passenger car or the like.

[0002]

2. Description of the Related Art Conventionally, there has been a liquefied gas fuel supply device which vaporizes a liquefied gas fuel stored in a fuel tank of a passenger car or the like and supplies it to an internal combustion engine as a prime mover through a fuel supply passage. As the liquefied gas fuel supply device, for example, as described in JP-A-4-325757, the excess gas phase gas generated in the storage tank is stored in the excess gas phase gas storage tank, and the excess gas is further stored. Some of them attempt to save fuel resources and prevent air pollution by reusing the phase gas as fuel for household gas appliances and the like.

[0003]

The liquefied gas fuel supply system illustrated above requires the installation of additional equipment such as piping and pressure reducing valves for conducting excess gas phase gas to household gas appliances. This is inconvenient because the pipes must be disconnected when the vehicle is operating and must be connected when the vehicle is parked.

It is an object of the present invention to provide a liquefied gas fuel supply device which does not require attachment / detachment of an additional device and can effectively utilize surplus gas phase gas.

[0005]

A liquefied gas fuel supply apparatus according to claim 1 vaporizes a liquefied gas fuel stored in a fuel tank and supplies it to an internal combustion engine via a surge tank provided in a fuel supply passage. A liquefied gas fuel supply device for discharging excess gas from a fuel tank, a catalyst combustion means provided at the end of the discharge path, and a fuel tank and a catalyst combustion means provided in the middle of the discharge path. An exhaust control valve that connects and disconnects the fuel tank, a buffer tank that is provided between the exhaust control valve and the fuel tank via a branch, and a refueling tank that communicates with the buffer tank to liquefy excess gas gas and supply it to the fuel tank. And a liquefaction device.

The liquefied gas fuel supply device according to claim 2 is
A supply control valve is provided between the buffer tank and the reliquefaction device,
The supply control valve is adapted to communicate when the inside of the buffer tank reaches a predetermined pressure.

The liquefied gas fuel supply device according to claim 3 is
Between the fuel tank and the branch portion of the discharge passage, a check valve for restricting the inflow of the surplus gas phase gas from the branch portion to the fuel tank is provided,
When the inside of the surge tank reaches a predetermined pressure, a relief valve that connects the surge tank and the branch portion is provided.

The liquefied gas fuel supply device according to claim 4 is
The catalytic combustion means detects the combustion catalyst layer, the heating means for heating the combustion catalyst layer when the excess gas phase gas in the fuel tank reaches a predetermined pressure, and the fact that the combustion catalyst layer reaches a predetermined temperature. And a discharge control section for communicating the discharge control valve.

[0009]

According to the liquefied gas fuel supply device of the first aspect, when the surplus gas phase gas in the fuel tank reaches a predetermined pressure, the discharge control valve is brought into a communication state and the surplus gas phase gas in the fuel tank is discharged. It can be discharged through and stored in a buffer tank. Furthermore, since the excess gas phase gas in the buffer tank can be liquefied by the reliquefaction device and supplied to the fuel tank, the excess gas phase gas can be reused as fuel. Further, the excess gas phase gas can be decomposed into carbon dioxide and water vapor and released into the atmosphere by catalytically burning with the catalytic combustion means provided at the end of the discharge passage.

According to the liquefied gas fuel supply device of the second aspect, when the pressure in the buffer tank reaches a predetermined pressure, the supply control valve provided between the buffer tank and the reliquefaction device is in a communication state, and the buffer tank Since the excess gas phase gas in the tank is configured to be supplied to the reliquefaction device, the frequency of activating the reliquefaction device can be suppressed and the excess gas phase gas can be efficiently reused. Further, the excess gas phase gas can be prevented from flowing back into the fuel tank.

According to the liquefied gas fuel supply device of the third aspect, the check valve provided between the branch portion of the discharge passage and the fuel tank prevents the excess gas phase gas from flowing into the switching valve from the branch portion side. Since it is regulated, if the inside of the surge tank provided in the fuel supply path reaches a predetermined pressure and the relief valve is in communication,
Gas-phase gas fuel in the surge tank flows into the buffer tank through the branch portion of the discharge path.

According to the liquefied gas fuel supply device of the fourth aspect, when the surplus vapor phase gas in the fuel tank reaches a predetermined pressure, the heating means starts heating the combustion catalyst layer, and further the combustion catalyst layer reaches a predetermined temperature. When it reaches, the emission control valve communicates with the emission control valve, so that when the excess gas phase gas is supplied to the catalyst combustion layer through the emission control valve, preheating of the catalyst combustion layer can be completed. Therefore, a chemical reaction for decomposing the surplus gas phase gas into hydrogen and carbon dioxide can be surely caused in the catalytic combustion layer, and harmful emissions such as carbon monoxide due to incomplete catalytic combustion and unreacted It is possible to prevent the combustion gas from being released into the atmosphere.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a liquefied gas fuel supply system according to an embodiment of the present invention vaporizes a liquefied gas fuel stored in a fuel tank 1 and, via a fuel supply passage 2, an internal combustion engine ( (Not shown) via a fuel injection valve, a discharge passage 3 for discharging the surplus vapor phase gas 1b from the fuel tank 1, and a catalytic combustion means 4 provided at the end of the discharge passage 3.
And a central control means represented by an ECU in the figure, and a discharge control which is provided in the middle of the discharge path 3 and connects / disconnects the fuel tank 1 and the catalytic combustion means 4 based on a command signal from the central control means. A valve 5; a first relief valve 6 provided between the fuel tank 1 and the discharge control valve 5 and brought into communication with each other when the surplus gas phase gas 1b in the fuel tank 1 reaches a predetermined pressure; A buffer tank 8 provided between the valve 5 and the first relief valve 6 via a branch portion 7, and a reliquefaction for communicating with the buffer tank 8 and liquefying the excess gas phase gas 1b and supplying it to the fuel tank 1. And the device 9.

The fuel tank 1 is provided in the fuel supply passage 2.
A pump 2a for sucking the liquid-phase gas fuel 1a therein, a vaporizer 10 for vaporizing the liquid-phase gas fuel 1a supplied through the pump 2a by exchanging heat with water as a medium, and the vaporizer 10 A second relief valve 11 that is in a communication state when the vaporized gas fuel vaporized in step 1 reaches a predetermined pressure that can be used as fuel to be supplied to the internal combustion engine; and a surge tank 12 that stores a predetermined amount of vapor-phase gas fuel. It is provided. The fuel tank 1 is provided with a first pressure gauge 13 for measuring the pressure of the surplus vapor phase gas 1b therein. The first relief valve 6 keeps the inside of the fuel tank 1 at a predetermined pressure to suppress the generation of the surplus gas phase gas 1b in the fuel tank 1.

The buffer tank 8 communicates with the reliquefaction device 9 via a surplus vapor phase gas supply passage 14 and a supply control valve 15 provided on the way of the surplus vapor phase gas supply passage 14. Between the discharge control valve 5 and the branch portion 7, there is provided a second pressure gauge for detecting that the surplus gas phase gas 1b in the buffer tank 8 has reached a predetermined pressure and transmitting a detection signal to the central control means. 16 are provided. The supply control valve 15 connects / disconnects the surplus gas phase gas supply passage 14 based on a command signal from the central control means that receives the detection signal of the second pressure gauge 16.

Between the first relief valve 6 and the branch portion 7 of the discharge passage 3, a reverse valve for restricting the inflow of the surplus gas phase gas 1b from the branch portion 7 to the first relief valve 6 is provided. A stop valve 3a is provided, and the surge tank 1 is provided at the branch portion 7.
When the inside of 2 reaches a predetermined pressure, a communication passage 18 having a third relief valve 17 that communicates the fuel supply passage 2 with the branch portion 7
Is provided. Since the reliquefaction device 9 is a well-known technique, detailed description and illustration thereof will be omitted.
A surplus gas phase gas compressor that compresses the surplus gas phase gas 1b in the buffer tank 8 by using the internal combustion engine as a drive source, and cools and condenses the surplus gas phase gas 1b compressed by the surplus gas phase gas compressor. One of them is a cold box to be used. In this case, it is preferable that the cold box includes a refrigerant compressor, a condenser, a throttle device and an evaporator, and forms a refrigeration cycle using nitrogen gas as a refrigerant.

As shown in FIG. 2, the catalytic combustion means 4 is provided with an opening 19a on one side surface of a reaction chamber 19 for introducing air from both sides, and an excess gas phase gas 1b can be passed through the opening 19a. A combustion catalyst layer 20 provided with a large number of through holes (not shown) is inserted, and the heating wire 2 for heating is inserted into the combustion catalyst layer 20.
1 in which the excess vapor phase gas 1b supplied through the discharge passage 3 is decomposed into carbon dioxide and heated steam. The power source of the heating wire 21 may be, for example, a battery 22 for an automobile. Further, a flow rate control valve with pressure correction 3b may be provided between the combustion catalyst layer 20 of the discharge passage 3 and the discharge control valve 5. In this case, the discharge amount of the excess gas phase gas 1b discharged from the discharge pipe 3 can be adjusted according to the reaction rate of the excess gas phase gas 1b in the combustion catalyst layer 20.

The heating wire 21 is a liquefied natural gas (LN) having a low catalytic combustion efficiency unless it reaches a predetermined temperature or higher.
It is preferably installed when G) or the like is used as a liquefied gas fuel. When hydrogen gas is used as the liquefied gas fuel, the heating efficiency of the catalytic combustion is high regardless of the temperature, so that the heating wire 21 can be dispensed with.

Further, as shown in FIG. 3, a discharge branch passage 24 and a flow control valve 3c with pressure correction are provided downstream of the discharge control valve 5, and the discharge branch passage 24 and the flow control valve 3c with pressure correction are provided. The excess vapor phase gas 1b is supplied to a reforming means (not shown) provided in the fuel cell 23, and the heated vapor generated in the catalyst layer 20 is added to the excess vapor phase gas 1b to cause a catalytic reaction and hydrogen. Produces gas,
Electromotive force may be obtained by supplying this hydrogen gas to the fuel electrode of the fuel cell 23 and introducing the atmosphere into the air electrode of the fuel cell 23. In this case, since the battery 22 can be charged by the electromotive force of the fuel cell 23, it is possible to prevent the internal combustion engine from being unable to start due to the self-discharge of the battery 22 even if the vehicle is parked for a long time.
Further, the fuel cell 23 is preferably a phosphoric acid type.

According to the liquefied gas fuel supply apparatus configured as described above, when the internal combustion engine is operated, the liquid phase gas fuel 1a in the fuel tank 1 is vaporized and the internal combustion gas is passed through the fuel supply passage 2. Supplied to the institution. On the other hand, when the pressure of the surplus vapor phase gas 1b in the fuel tank 1 reaches a predetermined pressure, the first relief valve 6 is brought into communication with the fuel tank 1
The surplus vapor phase gas 1b therein flows into the buffer tank 8. Further, when the internal combustion engine is operated at a relatively low speed and the fuel consumption decreases, and the pressure in the surge tank rises to reach a predetermined value, the third relief valve 17 enters the communication state. The gas-phase gas fuel in the surge tank 12 flows into the buffer tank 8 through the communication passage 18 and the branch portion 7.

Further, when the pressure in the buffer tank 8 reaches a predetermined pressure, the supply control valve 15 is brought into a communication state, and the excess gas phase gas 1b in the buffer tank 8 flows through the excess gas phase gas supply passage 14. Since it is supplied to the reliquefaction device 9 via the reliquefaction device 9 and liquefied by the reliquefaction device 9 and supplied to the fuel tank 1, the excess gas phase gas can be reused as fuel, which is economical.

When the internal combustion engine is stopped for a long time for parking or the like, the surplus gas phase gas 1b in the fuel tank 1 is
When the pressure reaches a predetermined pressure, the first relief valve 6 is brought into a communication state, and the surplus vapor phase gas 1b in the fuel tank 1 flows into the buffer tank 8. Further, when the pressure in the buffer tank 8 reaches a predetermined pressure, the discharge control valve 5 is brought into a communication state, and the excess gas phase gas 1b stored in the buffer tank 8 is supplied to the catalytic combustion means 4 to generate carbon dioxide. It is decomposed into water vapor and released into the atmosphere. Therefore, the surplus vapor phase gas 1b can be treated without causing air pollution, and an additional device or the like for using the surplus vapor phase gas 1b in a household gas appliance unlike the conventional case is unnecessary.

Further, the surplus gas phase gas 1b in the fuel tank 1
Has reached a predetermined pressure by the first pressure gauge 13, and based on this, heat control means for turning on the heating wire 21 and the fact that the combustion catalyst layer 20 has reached a predetermined temperature. A discharge control unit that detects and communicates the discharge control valve 5 may be incorporated in the central control means.
In this case, when the surplus gas phase gas 1b in the fuel tank 1 reaches a predetermined pressure, the combustion catalyst layer 20 is heated by the heating means.
When the combustion catalyst layer 20 reaches a predetermined temperature and the exhaust control valve 5 is brought into a communication state, the excess gas phase gas 1b is supplied to the catalytic combustion layer 20 through the exhaust control valve 5. At this time, the preheating of the catalyst combustion layer 20 can be completed. Therefore, a chemical reaction for decomposing the surplus gas phase gas 1b into hydrogen and carbon dioxide can be surely caused in the catalytic combustion layer 20, and generation of harmful emissions such as carbon monoxide due to incomplete catalytic combustion. Can be prevented.

A supply port 25 for supplying liquefied gas fuel is provided in the lower portion of the fuel tank 3, and between the fuel tank 1 of the discharge pipe 3 and the switching valve 10,
When the liquefied gas fuel is supplied from the supply port 25, a discharge port 26 for discharging the excess gas phase gas 1b staying in the fuel tank 1 is provided.

[0025]

According to the liquefied gas fuel supply device of the first aspect of the present invention, when the discharge control valve is in the communicating state, the surplus gas phase gas in the fuel tank can be discharged through the discharge passage and stored in the buffer tank. It is possible to prevent the explosion accident of the tank. Furthermore, since the surplus vapor phase gas stored in the buffer tank can be liquefied by the reliquefaction device and supplied to the fuel tank, the surplus vapor phase gas can be reused as fuel to reduce the fuel cost. Moreover, the surplus gas phase gas in the buffer tank can be decomposed into carbon dioxide and water vapor and released into the atmosphere by catalytically burning with the catalytic burning means provided at the end of the discharge passage.

Therefore, in addition to being economical because the excess gas phase gas can be reused, the excess gas phase gas is treated without causing air pollution, and the excess gas phase gas is used as a gas for household use as in the conventional case. It is not necessary to attach or detach an additional device for burning with a device, which improves usability.

According to the liquefied gas fuel supply device of the second aspect, when the pressure in the buffer tank reaches a predetermined pressure, the supply control valve provided between the buffer tank and the reliquefaction device is in a communicating state, and Since the excess gas phase gas in the tank is configured to be supplied to the reliquefaction device, the frequency of activating the reliquefaction device can be suppressed and the excess gas phase gas can be efficiently reused. Further, the excess gas phase gas can be prevented from flowing back into the fuel tank. Therefore, it is possible to prevent the liquid phase gas in the fuel tank from being heated and vaporized by the surplus gas phase gas.

According to the liquefied gas fuel supply device of the third aspect, when the pressure in the surge tank reaches a predetermined pressure, the relief valve connects the discharge passage and the surge tank so that the gas fuel gas in the surge tank is discharged to the discharge passage. Inflow. Therefore, even if the fuel consumption is reduced by operating the internal combustion engine at a relatively low speed, for example, it is possible to prevent the surge tank provided in the fuel supply passage from becoming high in pressure and to supply a stable fuel. Is.
In addition, the check valve provided in the discharge path causes excess gas phase gas or gas phase gas fuel in the surge tank that has flowed into the discharge path through the relief valve or excess gas phase gas accumulated in the discharge path to flow back into the fuel tank. Can be prevented.

According to the liquefied gas fuel supply apparatus of the fourth aspect, when the surplus vapor phase gas in the fuel tank reaches a predetermined pressure, the heating means starts heating the combustion catalyst layer, and further the combustion catalyst layer reaches a predetermined temperature. When it reaches, the emission control valve communicates with the emission control valve, so that when the excess gas phase gas is supplied to the catalyst combustion layer through the emission control valve, preheating of the catalyst combustion layer can be completed. Therefore, a chemical reaction for decomposing the surplus gas phase gas into hydrogen and carbon dioxide can be surely caused in the catalytic combustion layer, and the generation of harmful emissions such as carbon monoxide due to incomplete catalytic combustion is prevented. , Can prevent air pollution.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a liquefied gas fuel supply device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of catalytic combustion means in the liquefied gas fuel supply device according to one embodiment of the present invention.

FIG. 3 is a schematic view of a modified example of the catalytic combustion means in the liquefied gas fuel supply device of one embodiment of the present invention.

[Explanation of symbols]

 1 Fuel Tank 2 Fuel Supply Channel 3 Discharge Channel 4 Catalytic Combustion Means 5 Emission Control Valve 7 Branch Section 8 Buffer Tank 9 Reliquefaction Supply Device 12 Surge Tank

Claims (4)

[Claims] 1. A liquefied gas fuel supply device which vaporizes liquefied gas fuel stored in a fuel tank and supplies it to an internal combustion engine through a surge tank provided in a fuel supply path, wherein excess gas is supplied from the fuel tank. An exhaust passage for exhausting the phase gas, a catalytic combustion means provided at the end of the exhaust passage, an exhaust control valve provided in the middle of the exhaust passage for connecting and disconnecting the fuel tank and the catalytic combustion means, and the exhaust control Liquefied gas fuel supply including a buffer tank provided between a valve and a fuel tank via a branch portion, and a reliquefaction device that communicates with the buffer tank and liquefies the excess gas phase gas to supply the liquefied gas to the fuel tank apparatus. 2. A supply control valve is provided between the buffer tank and the reliquefaction device, and the supply control valve is connected when the pressure in the buffer tank reaches a predetermined pressure. Liquefied gas fuel supply device. 3. A check valve for restricting an inflow of surplus gas phase gas from the branch portion to the fuel tank is provided between the fuel tank and the branch portion of the discharge passage, and the inside of the surge tank has a predetermined pressure. 2. The liquefied gas fuel supply device according to claim 1, further comprising a relief valve that communicates the surge tank with the branch portion when reaching the temperature. 4. The catalytic combustion means comprises: the combustion catalyst layer; a heating means for heating the combustion catalyst layer when the excess gas phase gas in the fuel tank reaches a predetermined pressure; and the combustion catalyst layer. The liquefied gas fuel supply device according to claim 1, further comprising: an exhaust control unit that detects when a predetermined temperature is reached and connects the exhaust control valve.