JP2012122496A - Gas fuel feeding apparatus for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow refuelling with a liquefied gas fuel, even in an environment where a refilling station that can supply a liquefied gas fuel is not in the neighborhood.SOLUTION: A gas fuel feeding apparatus 100 for a vehicle 1 driven by a natural gas fuel fed from a liquefied natural gas (LNG) tank 11, is installed in the vehicle 1 and includes the LNG tank 11 filled with a liquefied LNG. The gas fuel feeding apparatus includes: a compressed natural gas (CNG) tank 21 filled with a natural gas fuel in a compressed gaseous state; a coupling passage 41 for introducing the CNG in the CNG tank 21 to the LNG tank 11; and a pressure regulating valve 42 disposed in the coupling passage 41 and reducing the pressure of the CNG introduced from the CNG tank 21.

Description

  The present invention relates to a gas fuel supply device that supplies gas fuel to a vehicle.

  2. Description of the Related Art Conventionally, vehicles that use gas fuel such as CNG (Compressed Natural Gas) and LNG (Liquid Natural Gas) are known.

  Patent Document 1 discloses a fuel system for a liquefied natural gas vehicle. In such a liquefied natural gas vehicle, liquid phase LNG is vaporized by a vaporizer and supplied to the engine in a CNG state.

JP 2010-144845 A

  By the way, since several hundred supply facilities for supplying CNG to vehicles are provided nationwide, it is relatively easy to supply CNG. On the other hand, since only one replenishment facility for replenishing LNG to vehicles is provided nationwide, it may be difficult to replenish LNG depending on the direction of travel.

  The present invention has been made in view of the above problems, and an object of the present invention is to enable replenishment of liquefied gas fuel even in an environment where there is no replenishment facility in the vicinity that can replenish liquefied gas fuel. .

  The present invention is a gas fuel supply device for a vehicle that includes a liquefied gas tank that is mounted on a vehicle and that is filled with liquefied gas fuel, and that travels with the gas fuel supplied from the liquefied gas tank. A compressed gas tank that is compressed and filled in the above state, a connecting passage that leads the gas fuel in the compressed gas tank to the liquefied gas tank, and a pressure that is provided in the connecting passage and depressurizes the gas fuel that is led from the compressed gas tank And a regulating valve.

  According to the present invention, the gas fuel can be liquefied by reducing the pressure of the gas fuel filled in the compressed gas tank and supplying it to the low-temperature liquefied gas tank. Therefore, even in an environment where there is no replenishment facility in the vicinity where liquefied gas fuel can be replenished, liquefied gas fuel can be replenished by the gas fuel replenished to the compressed gas tank.

It is a lineblock diagram of a fuel supply device concerning an embodiment of the invention. It is a flowchart figure which shows the effect | action of a fuel supply apparatus.

  Hereinafter, a gas fuel supply apparatus 100 according to an embodiment of the present invention will be described with reference to the drawings.

  First, the configuration of the gas fuel supply apparatus 100 will be described with reference to FIG.

  The gas fuel supply device 100 is mounted on the vehicle 1 and supplies gas fuel to the engine 2 that generates the driving force of the vehicle 1. Below, the case where natural gas is used as gas fuel is demonstrated.

  In general, natural gas used as gas fuel includes CNG (Compressed Natural Gas) compressed to several tens of kPa in a gaseous state, and liquefied LNG (Liquid Natural Gas). There is.

  About 90% of natural gas used as CNG and LNG is methane, and in addition, ethane, propane, butane and the like are included. The normal boiling point of methane at 1 atm is -161.5 ° C. The boiling point of methane rises according to the pressure, and when it exceeds a critical temperature of −82.6 ° C., it does not liquefy no matter how much pressure is applied. Since the boiling point of methane is the lowest among the components contained in natural gas, if methane is liquefied, other components will be liquefied.

  Natural gas has a volume of about 1/600 when liquefied from the gaseous state. For this reason, when LNG is mounted on a vehicle as gas fuel, a fuel tank of the same capacity can be loaded with tens of times more fuel than CNG. Therefore, by using LNG as the gas fuel, the cruising range of the vehicle can be extended as compared with the case of using CNG.

  The gas fuel supply device 100 includes an LNG supply unit 10 that supplies the LNG filled in the LNG tank 11 as a liquefied gas tank to the engine 2, and a CNG that supplies the CNG filled in the CNG tank 21 as a compressed gas tank to the engine 2. A supply unit 20 and a reliquefaction unit 40 that reliquefies CNG in the CNG tank 21 to generate LNG are provided. The gas fuel supply apparatus 100 includes a controller (not shown), and the fuel supply is controlled by the controller.

  The gas fuel supply apparatus 100 includes a switching valve 31 that selects which of the LNG supplied from the LNG supply unit 10 and the CNG supplied from the CNG supply unit 20 is supplied to the engine 2, and the CNG to the engine 2. And an on-off valve 32 capable of shutting off the supply.

  The switching valve 31 is a valve that selectively switches between supplying the engine 2 with CNG vaporized LNG in the LNG tank 11 or supplying the engine 2 with CNG in the CNG tank 21. The switching valve 31 is controlled to be switched by a controller, and normally supplies CNG in the CNG tank 21 to the engine 2 preferentially.

  The on-off valve 32 supplies the CNG that has passed through the switching valve 31 to the engine 2 when switched to the open state, and shuts off the supply of CNG that has passed through the switching valve 31 to the engine 2 when switched to the closed state. To do. The on-off valve 32 is controlled to open and close by a controller.

  Hereinafter, the LNG supply unit 10 will be described.

  The LNG supply unit 10 includes an LNG tank 11 filled with LNG, and an on-off valve 12 that can shut off the supply of LNG from the LNG tank 11.

  The LNG tank 11 is a tank capable of storing LNG inside. The LNG tank 11 stores the filled LNG at an extremely low temperature of −100 ° C. or lower. The LNG tank 11 is formed in a thermos structure, and heat transfer with the outside is suppressed.

  Inside the LNG tank 11, together with the liquefied LNG, a natural gas in a gas state formed by vaporizing a part of LNG called “boil-off gas” (BOG) is stored. The pressure inside the LNG tank 11 is about 2 MPa.

  The LNG tank 11 includes a filling port 11a through which LNG can be supplied from the outside, a temperature detector 11b that detects the temperature of the internal LNG, and a pressure detector 11c that detects the pressure of the internal LNG.

  The filling port 11a is a hole for supplying LNG from the outside. The filling port 11a is normally closed and is opened when replenishing LNG at a replenishment facility capable of replenishing LNG. The filling port 11a is provided with a check valve (not shown) that prevents the LNG in the LNG tank 11 from flowing out.

  The temperature detector 11b detects the temperature of the LNG in the LNG tank 11 and transmits it to the controller, and the pressure detector 11c detects the pressure of the LNG in the LNG tank 11 and transmits it to the controller.

  When the on-off valve 12 is switched to the open state, the CNG guided from the LNG tank 11 can be supplied to the engine 2, and when it is switched to the closed state, the supply of the CNG guided from the LNG tank 11 to the engine 2 is enabled. Cut off. The on-off valve 12 is controlled to open and close by a controller.

  The LNG supply unit 10 is supplied from the buffer tank 14 to the engine 2, the vaporizer 13 that vaporizes the LNG supplied from the LNG tank 11 to make CNG, the buffer tank 14 that stores the CNG vaporized by the vaporizer 13, and the like. And a pressure adjusting valve 15 for adjusting the pressure of the CNG.

  The vaporizer 13 vaporizes cryogenic LNG using cooling water for cooling the engine 2. In the vaporizer 13, LNG is vaporized into CNG by heat exchange with the cooling water whose temperature has increased to about 100 ° C. due to the heat of the engine 2.

  The buffer tank 14 temporarily stores CNG vaporized by the vaporizer 13. By providing the buffer tank 14, when the load of the engine 2 increases and a large amount of fuel is required, the vaporization of LNG by the vaporizer 13 is not in time, and gas fuel becomes insufficient.

  The pressure adjustment valve 15 is a valve that is controlled by the controller and adjusts the supply pressure of the CNG stored in the buffer tank 14 to the engine 2. The CNG whose pressure is adjusted by the pressure adjusting valve 15 passes through the switching valve 31 and the on-off valve 32 and is supplied to the engine 2.

  Hereinafter, the CNG supply unit 20 will be described.

  The CNG supply unit 20 includes a CNG tank 21 filled with CNG, an on-off valve 22 that can shut off the supply of CNG from the CNG tank 21, and a pressure that adjusts the pressure of CNG supplied from the CNG tank 21 to the engine 2. And a regulating valve 25.

  The CNG tank 21 is a tank capable of storing CNG therein. The CNG tank 21 holds the filled CNG at a low temperature. The CNG tank 21 is formed in a thermos structure, and heat transfer with the outside is suppressed.

  In the CNG tank 21, natural gas in a gas state compressed to about 20 MPa is stored.

  The CNG tank 21 has a filling port 21a through which CNG can be supplied from the outside, and a pressure detector 21c that detects the pressure of the internal CNG.

  The filling port 21a is a hole for supplying CNG from the outside. The filling port 21a is normally closed and is opened when supplying CNG at a supply facility capable of supplying CNG. The filling port 21a is provided with a check valve (not shown) that prevents CNG in the CNG tank 21 from flowing out.

  The pressure detector 21c detects the pressure of CNG in the CNG tank 21 and transmits it to the controller.

  When the on-off valve 22 is switched to the open state, the CNG stored in the CNG tank 21 can be supplied to the engine 2, and when it is switched to the closed state, the supply of the CNG stored in the CNG tank 21 to the engine 2 is enabled. Cut off. The on-off valve 22 is controlled to open and close by a controller.

  The pressure adjustment valve 25 is a valve that is controlled by the controller and adjusts the supply pressure of the CNG stored in the CNG tank 21 to the engine 2. The CNG whose pressure is adjusted by the pressure adjustment valve 25 passes through the switching valve 31 and the on-off valve 32 and is supplied to the engine 2.

  Hereinafter, the reliquefaction unit 40 will be described.

  The reliquefaction unit 40 includes a connection passage 41 that guides CNG in the CNG tank 21 to the LNG tank 11, a pressure adjustment valve 42 that is provided in the connection passage 41 and depressurizes CNG that is guided from the CNG tank 21, and the connection passage 41 And an on-off valve 43 capable of shutting off the CNG.

  The connection passage 41 is a passage for guiding the CNG stored in the CNG tank 21 to the LNG tank 11 in order to liquefy the LNG.

  The pressure adjustment valve 42 is controlled by a controller and depressurizes CNG guided from the CNG tank 21. The internal pressure of the CNG tank 21 is about 20 MPa, and the internal pressure of the LNG tank 11 is about 2 MPa. By providing the pressure adjustment valve 42, the pressure of CNG is lowered, and CNG in the CNG tank 21 is prevented from flowing into the LNG tank 11 at a stretch. That is, the flow rate of CNG guided into the LNG tank 11 is adjusted by providing the pressure adjustment valve 42.

  The CNG that has passed through the pressure regulating valve 42 is bubbled by the LNG in the LNG tank 11 and is cooled and liquefied by the cryogenic LNG in the LNG tank 11.

  When CNG is depressurized by the pressure regulating valve 42, CNG adiabatically expands and the temperature decreases. Therefore, when CNG is adiabatically expanded by the pressure regulating valve 42 and the temperature is lowered, it becomes easy to liquefy when CNG is bubbled into LNG.

  Moreover, since LNG vaporizes when the temperature rises, it is necessary to maintain the temperature of LNG in the LNG tank 11 at a very low temperature. When CNG is adiabatically expanded by the pressure regulating valve 42 and the temperature is lowered, an increase in the temperature in the LNG tank 11 when the CNG is bubbled is suppressed accordingly.

  The pressure regulating valve 42 is heated from the outside by a heat retaining device (not shown) through which the cooling water of the engine 2 is guided. As a result, the pressure adjustment valve 42 can operate for pressure adjustment even if the temperature drops due to adiabatic expansion of CNG.

  When the open / close valve 43 is switched to the open state, the CNG guided from the CNG tank 21 can be supplied to the LNG tank 11, and when switched to the closed state, the CNG guided from the CNG tank 21 is shut off. The on-off valve 43 is controlled to open and close by a controller, and can be switched to an open state when the temperature of the LNG detected by the temperature detector 11b is equal to or lower than a predetermined temperature. This predetermined temperature is a temperature at which the LNG in the LNG tank 11 can be maintained in a liquefied state even when CNG is introduced into the LNG tank 11, and is set to about −100 ° C.

  Next, re-liquefaction of CNG in the gas fuel supply apparatus 100 will be described with reference to FIG.

  In step 101, it is determined whether or not the pressure of CNG filled in the CNG tank 21 is larger than the minimum pressure of the CNG tank 21. This minimum pressure is set to the lowest pressure at which CNG can be supplied from the CNG tank 21 to the engine 2.

  If it is determined in step 101 that the CNG pressure is greater than the minimum pressure, the process proceeds to step 102. On the other hand, when it is determined in step 101 that the pressure of CNG is equal to or lower than the minimum pressure, the process proceeds to step 106 and the re-liquefaction of CNG is stopped.

  In step 102, it is determined whether or not the volume of the LNG filled in the LNG tank 11 is smaller than the maximum volume of the LNG tank 11. The maximum volume is the volume of the LNG tank.

  If it is determined in step 102 that the volume of the LNG is smaller than the maximum volume, there is a free capacity remaining in the LNG tank 11, and the process proceeds to step 103. On the other hand, if it is determined in step 102 that the volume of the LNG is the maximum volume, since there is no free capacity remaining in the LNG tank 11, the process proceeds to step 106 and the re-liquefaction of CNG is stopped.

  In step 103, it is determined whether or not the pressure of the LNG filled in the LNG tank 11 is smaller than the maximum pressure of the LNG tank 11. This maximum pressure is set to the maximum pressure that the LNG tank 11 can withstand.

  If it is determined in step 103 that the pressure of the LNG is smaller than the maximum pressure, the LNG tank 11 can be durable even if the LNG tank 11 is filled with CNG and reliquefaction is performed. Transition. On the other hand, if it is determined in step 103 that the LNG pressure is the maximum pressure, the pressure in the LNG tank 11 cannot be increased any more, so the routine proceeds to step 106 and the re-liquefaction of CNG is stopped. .

  In step 104, it is determined whether or not the temperature of the LNG in the LNG tank 11 detected by the temperature detector 11b is lower than a predetermined temperature. This predetermined temperature is set to about −100 ° C. at which the LNG in the LNG tank 11 can be maintained in a liquefied state, but is set to −82.6 ° C., which is a critical temperature at which CNG can be liquefied regardless of pressure. May be.

  If it is determined in step 104 that the temperature of the LNG is lower than the predetermined temperature, the LNG tank 11 can be liquefied by filling CNG, and therefore the process proceeds to step 105. On the other hand, if it is determined in step 104 that the temperature of the LNG is equal to or higher than the predetermined temperature, the temperature of the LNG is high and there is a possibility that the CNG cannot be liquefied. Cancel.

  In step 105, the on-off valve 43 is switched to an open state by the controller. As a result, CNG can be supplied from the CNG tank 21 to the LNG tank 11, and the CNG adjusted by the pressure adjustment valve 42 is bubbled into the LNG in the LNG tank 11 and liquefied.

  In a state where the on-off valve 43 is switched to the open state, the CNG guided from the CNG tank 21 is depressurized by the pressure regulating valve 42 provided in the connection passage 41, and the LNG tank 11 filled with the cryogenic LNG is supplied to the LNG tank 11. It is liquefied by being bubbled. Therefore, even in an environment where there is no replenishment facility in the vicinity where LNG can be replenished, LNG can be replenished to the LNG tank 11 by the CNG replenished to the CNG tank 21.

  In addition, in a state where the LNG in the LNG tank 11 remains sufficiently, the CNG tank 21 is replenished with CNG at a replenishment facility capable of replenishing CNG, thereby liquefying the CNG replenished in a gaseous state and LNG tank. 11 to refill the LNG tank 11 again. Thus, by supplying CNG to the CNG tank 21, the LNG in the LNG tank 11 can always be maintained in a nearly full state.

  Therefore, when LNG is mounted on the vehicle 1, a fuel tank of the same capacity can be loaded with several tens of times more fuel than in the case of CNG. Therefore, natural gas replenished as CNG is liquefied and converted into LNG. By mounting on the vehicle 1, the cruising range of the vehicle 1 can be extended.

  On the other hand, in step 106, the on-off valve 43 is switched to the closed state by the controller. As a result, the supply of CNG from the CNG tank 21 to the LNG tank 11 is cut off, and the LNG supply unit 10 and the CNG supply unit 20 supply CNG to the engine 2 independently of each other.

  According to the above embodiment, the following effects are obtained.

  CNG can be liquefied by reducing the pressure of the CNG guided from the CNG tank 21 by the pressure regulating valve 42 provided in the connection passage 41 and supplying it to the LNG tank 11 filled with the cryogenic LNG. Therefore, even in an environment where there is no replenishment facility in the vicinity where LNG can be replenished, LNG can be replenished to the LNG tank 11 by the CNG replenished to the CNG tank 21.

  Further, when LNG is mounted on the vehicle 1, a fuel tank of the same capacity can be loaded with tens of times more fuel than in the case of CNG. Therefore, natural gas replenished as CNG is liquefied and converted into LNG. By mounting on the vehicle 1, the cruising range of the vehicle 1 can be extended.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The gas fuel supply device of the present invention can be used as a device for supplying gas fuel to an engine in a vehicle.

DESCRIPTION OF SYMBOLS 100 Gas fuel supply apparatus 1 Vehicle 10 LNG supply part 11 LNG tank 11b Temperature detector 20 CNG supply part 21 CNG tank 31 Switching valve 40 Reliquefaction part 41 Connection passage 42 Pressure adjustment valve 43 On-off valve

Claims (4)

Equipped with a liquefied gas tank mounted on a vehicle and filled with liquefied gas fuel,
A gas fuel supply device for a vehicle that travels with gas fuel supplied from the liquefied gas tank,
A compressed gas tank filled with the gas fuel compressed in a gaseous state;
A connecting passage for guiding the gas fuel in the compressed gas tank to the liquefied gas tank;
A gas fuel supply device for a vehicle, comprising: a pressure adjusting valve provided in the connection passage and depressurizing gas fuel guided from the compressed gas tank. The compressed gas tank can be supplied with gaseous fuel in a gaseous state from the outside,
The gas fuel supply device for a vehicle according to claim 1, wherein the liquefied gas tank can be supplied with liquefied gas fuel from the outside. A temperature detector for detecting the temperature of the gas fuel filled in the liquefied gas tank;
An on-off valve provided in the connecting passage and capable of shutting off a flow of gas fuel,
The gas fuel for a vehicle according to claim 1 or 2, wherein the on-off valve is switchable to an open state when the temperature of the gas fuel detected by the temperature detector is equal to or lower than a predetermined temperature. Feeding device.   The gas fuel supply device for a vehicle according to any one of claims 1 to 3, wherein the vehicle can be driven also by gas fuel supplied from the compressed gas tank.

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