KR101199326B1 - Fuel tank for gas fuel vehicles and fuel charge method thereof - Google Patents

Abstract

The present invention relates to a fuel tank for a gas fuel vehicle and a method for refilling the fuel thereof, the bomb being formed as a high pressure container forcibly protected to protect the gas fuel stored therein from shock or vibration and injected into the cylinder to form a predetermined pressure. And a pressure forming gas, the pressure forming gas having a configuration to be injected before the first injection of the gaseous fuel.
By using the fuel tank for the gas fuel vehicle as described above and the fuel filling method thereof, the present invention forms a constant pressure by injecting a pressure forming gas into the inside of the cylinder, even if the pressure of the LPG fuel in the cold state in winter, the pressure is formed The LPG fuel in the liquid state is smoothly supplied to the engine by the pressure formed by the gas.

Description

FUEL TANK FOR GAS FUEL VEHICLES AND FUEL CHARGE METHOD THEREOF

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank for a gas fuel vehicle and a fuel charging method thereof, and more particularly to a fuel tank for a gas fuel vehicle and a fuel charging method for providing a gas fuel and discharging the charged gas fuel at a constant pressure to the engine. It is about.

In general, the gas fuel vehicle is a reciprocating force generated by inhaling and mixing a mixture of gas fuel and air into the combustion chamber of the engine, and the linear reciprocating motion of the piston up and down, and converts the linear reciprocating motion of the piston into the rotation of the crank mechanism Obtain the engine's rotational power.

The engine of such a gas fueled vehicle liquefies and stores liquefied petroleum gas (LPG) fuel or natural gas fuel in a fuel tank, a predetermined pressure, and stores liquid fuel by means of a fuel pump. After the injection by the injector, the engine is vaporized during the operation of the engine is supplied to the combustion chamber together with the air in the form of a mixer.

1 is a cross-sectional view of a fuel tank for a general gas fuel vehicle using LPG fuel.

As shown in FIG. 1, a fuel tank for a general gas fuel vehicle is formed of a cylinder 1, which is a high-pressure container that is forced to protect the fuel tank from shocks or vibrations, and the cylinder 1 is formed by a bracket 2. Is fixed to.

The cylinder 1 is provided with a multi-valve 3 for discharging the gaseous fuel charged inside the cylinder 1 by the pumping pressure of the fuel pump and a filling valve 4 for filling the gaseous fuel through the fuel inlet 5. do.

The filling valve 4 has a housing 6 which protrudes to the outside of the cylinder 1 so as to maintain the airtightness of the fuel tank by the packing, and the filling pipe connected to the inside of the cylinder 1 from the housing 6. An overcharge preventing valve 8 and a float 9 are fixed to (7).

Outside the housing 6 is provided with a safety valve and a manual valve (not shown) that opens when the set pressure is exceeded.

The overcharge preventing valve 8 is filled with LPG fuel by about 85% of the volume of the entire cylinder 1 in order to prevent the pressure inside the cylinder 1 from being excessively increased by filling the LPG fuel. When 9 rises, the tip of the filling pipe 7 is closed to stop charging.

As shown in FIG. 1, a general fuel tank for a gas fuel vehicle configured as described above is provided with a tip A of the filling pipe 7 of the filling valve 4 spaced apart from the oil surface by a predetermined height.

This prevents the filling performance from deteriorating while excessively increasing the pressure of the liquid gas fuel layer (hereinafter referred to as the 'liquid layer') when the tip of the filling pipe 7 is installed at a position lower than the oil surface B. It is for.

As a result, the gaseous fuel charged into the cylinder 1 is injected into the gaseous gas fuel layer (hereinafter, referred to as a 'gas layer') through the tip of the filling pipe 7 to the upper layer of the inside of the cylinder 1. It is charged to fall into the liquid phase of.

LPG used in such a gas fuel vehicle is a mixture containing butane and propane as a main component.

Pure LPG has no color, smell, or taste, but intentionally mixes unpleasant odors in case of leakage. The specific gravity of LPG is lighter than water in liquid state, but it is 1.5 ~ 2 times heavier than air in gaseous state.

Since butane has a melting point of -135 ° C and a boiling point of -0.5 ° C, when the temperature drops below freezing in winter, there is a problem in that starter of the engine is inferior because liquid butane mixed in LPG is not vaporized.

Therefore, LPG filled in the winter vehicle is mixed by increasing the mixing amount of propane having a melting point of 187 ℃ and a boiling point of -47.07 ℃.

However, there is a limit in the mixing ratio of propane to butane (maximum 7: 3), so even if propane is mixed, there is a limit to solve the deterioration of startability of the gas fuel vehicle using LPG in winter.

The present invention is to solve the problems as described above, an object of the present invention is to provide a fuel tank for a gas fuel vehicle and a fuel charging method thereof for forming a predetermined pressure inside the fuel tank of the gas fuel vehicle.

Another object of the present invention is to provide a fuel tank for a gas fuel vehicle and a fuel charging method thereof, which can improve winter startability of the gas fuel vehicle.

Still another object of the present invention is to provide a fuel tank for a gas fuel vehicle and a fuel charging method thereof, which maintain a constant pressure on the gaseous side in the fuel tank during gas fuel filling.

Still another object of the present invention is to provide a fuel tank for a gas fuel vehicle and a fuel charging method thereof, which can maintain a discharge pressure of a gas fuel discharged from a fuel tank to a fuel line at a predetermined level.

According to a feature of the present invention for achieving the object as described above, the present invention is to form a cylinder and a predetermined pressure in the cylinder formed of a high pressure vessel forcibly to protect the gas fuel stored therein from shock or vibration. And a pressure forming gas to be injected, which pressure is injected before the first injection of the gaseous fuel.

The pressure forming gas may be nitrogen or an inert gas.

The pressure forming gas is characterized in that the gas lighter than the gas fuel.

The pressure forming gas may be injected at a pressure between a preset maximum pressure and a minimum pressure of the remaining space remaining after the gas fuel is filled in the cylinder.

The fuel tank has a filling valve for injecting and filling gas fuel into the cylinder and a multi-valve for discharging the gas fuel charged in the cylinder, wherein the filling valve is protruded to the outside of the cylinder, the housing; A fuel inlet coupled to one side of the housing and injected by injecting an external gaseous fuel and a filling pipe connected to the position close to the lower end of the bomb inner space from the fuel inlet, the filling pipe includes The liquid discharge port is formed at the tip of the filling pipe so as to be close to the lower end and the gas phase discharge hole is formed in the upper portion of the filling pipe so as to be close to the upper end of the cylinder inner space.

According to another feature of the invention, the present invention (a) injecting the pressure forming gas into the cylinder, (b) the gas fuel through the fuel inlet in the cylinder in which the pressure forming gas is injected in step (a) And (c) filling the gaseous fuel injected in the step (b) into the cylinder through a filling pipe connected to the fuel inlet, and in the step (a), the pressure forming gas. Is injected at a pressure between the maximum pressure inside the cylinder and a predetermined minimum pressure.

The step (b) is to fill the gas fuel through the gas discharge outlet formed in the upper portion of the filling pipe so as to approach the upper end of the cylinder inner space and the liquid discharge hole formed in the lower portion of the filling pipe so as to approach the lower end of the cylinder inner circumference It features.

As described above, the present invention forms a constant pressure in the gas phase layer by using the pressure forming gas injected into the cylinder, even if the pressure of the LPG fuel stored in the cylinder is lowered in the winter low temperature state, the liquid phase from the liquid phase Supply LPG fuel to the engine smoothly.

Accordingly, the present invention can improve the winter startability and restartability of the gas fuel vehicle.

In addition, the present invention fills the gaseous fuel in the liquid phase through the liquid discharge port and simultaneously injects a part of the gaseous fuel into the gas phase layer through the gaseous discharge port.

That is, the present invention compensates the pressure increase amount of the gas phase layer by filling the liquid phase layer and the gaseous fuel in the gas phase layer to offset the pressure decrease amount of the gas phase layer due to the decrease in the temperature of the gas phase layer to maintain a constant pressure inside the bombeous layer. It is possible to prevent the filling delay of gas fuel due to excessive pressure rise.

As a result, the present invention maintains the pressure inside the cylinder at the time of filling the gas fuel to maintain the discharge pressure of the gas fuel discharged from the fuel tank to the fuel line at a constant level to prevent engine relief and start-up due to the discharge pressure drop. Can be removed

1 is a cross-sectional view of a fuel tank for a general gas fuel vehicle using LPG fuel.
2 is a cross-sectional view showing the configuration of a fuel tank for a gas fuel vehicle according to an embodiment of the present invention.
Figure 3 is an operating state showing the state in which the pressure forming gas is injected.
Figure 4 is an operating state showing a state in which the LPG fuel is fully charged.
5 is a flowchart illustrating a step-by-step method of recharging a fuel tank for a gas fuel vehicle according to an exemplary embodiment of the present invention.

Hereinafter, a fuel tank for a gas fuel vehicle and a fuel charging method thereof according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present embodiment, the fuel pump is installed in the exterior of the fuel tank, but it should be noted that the present invention can be applied to the internal type in which the fuel pump is installed in the fuel tank.

2 is a cross-sectional view showing the configuration of a fuel tank for a gas fuel vehicle according to a preferred embodiment of the present invention, Figure 3 is an operating state diagram showing a state in which the pressure forming gas is injected, Figure 4 is a state filled with LPG fuel The operation state diagram shown.

As shown in FIG. 2, the fuel tank for a gas fuel vehicle according to the preferred embodiment of the present invention is formed of a cylinder 10, which is a high-pressure container forcibly formed to form an exterior and protect fuel charged therein from shock or vibration. The cylinder 10 is fixed to the vehicle body by the bracket 11.

The cylinder 10 is injected with a pressure forming gas G before the LPG fuel F is first injected to form a constant pressure inside the cylinder 10.

As shown in Figure 3, the pressure forming gas (G) is preferably injected before delivery after performing the airtight test of the cylinder 10 produced by the cylinder 10 producer.

Accordingly, the pressure forming gas G is injected into the cylinder 10 at a predetermined pressure to form a constant pressure throughout the cylinder.

The pressure forming gas (G) is inert gas such as helium (He), neon (Ne), argon (Ar), and krypton (Kr) at room temperature or in a chemically stable state so as not to be mixed with the LPG fuel (F). A chemically inert nitrogen (N ₂ ) gas is used.

On the other hand, the molecular weight of butane (C ₄ H ₁₀ ) contained in the LPG fuel (F) is 58 g / mol, and the molecular weight of propane (C ₃ H ₈ ) is 44 g / mol.

Therefore, the pressure forming gas (G) is a nitrogen (N ₂ ) gas or monoatomic molecular gas that is lighter than the LPG fuel (F) to be positioned higher than the LPG fuel (F) inside the cylinder 10 for smooth fuel supply. Among them, helium (He), neon (Ne), and argon (Ar) are preferably used.

Table 1 is a characteristic table of the gas used as the pressure forming gas.

Gas name Melting point (℃) Boiling Point (℃) Molecular Weight (g / mol) Nitrogen (N ₂ ) -210.00 -195.79 28 Helium (He) -272.20 -268.93 4 Neon -248.59 -246.08 20 Argon (Ar) -189.35 -185.35 39 Krypton (Kr) -157.36 -153.22 96

Since the pressure forming gas G has a melting point and a boiling point of −100 ° C. or lower, as shown in Table 1, the pressure forming gas G may maintain a gas state even in a low temperature state in winter to form a constant pressure inside the bomb 10.

To this end, the pressure forming gas G is injected into the cylinder 10 at a pressure calculated by Equation 1 below.

Here, P ₁ is the pressure of the pressure forming gas (G) injected into the cylinder 10, V ₁ is the volume of the cylinder 10, P ₂ is the pressure forming gas in a state where the LPG fuel (F) is full and a pressure of (G), V ₂ is a volume of the pressure-forming gas (G) in which the LPG fuel (F) fully charged.

In general, the pressure of filling the LPG fuel (F) in the gas filling station is about 8 bar, and when the LPG fuel (F) is fully charged to the cylinder 10 at atmospheric pressure, the pressure inside the cylinder is about 4 bar.

Therefore, the pressure P2 of the pressure forming gas G in the fully charged state as shown in FIG. 4 is set to a maximum pressure, for example, less than about 4 bar, in order to prevent the pressure inside the cylinder 10 from being excessively high.

For example, set P ₂ to about 3.3 bar, V ₁ to 85 liters of the volume of the cylinder 10 applied to a typical gas fuel vehicle, and V ₂ to about 13 liters, which is about 15% of V ₁ . By substituting the equation (1), the pressure P ₁ of the pressure forming gas G injected into the cylinder 10 is about 0.5 bar.

And when the pressure of the LPG fuel (F) stored in the cylinder 10 is lowered to about 0 bar at low temperature in winter, the pressure of the pressure forming gas (G) to release the LPG fuel (F) to the outside is the minimum pressure, for example about 1 bar The pressure is set to form the above pressure.

For example, when P ₂ is set to about 1.3 bar, V ₁ is set to 85 L, and V ₂ is set to about 13 L and substituted into Equation 1, the pressure forming gas G injected into the cylinder 10. The pressure of P ₁ is about 0.2 bar.

As a result, in the present embodiment, the pressure forming gas G is injected at a pressure of about 0.2 to 0.5 bar.

The present invention forms a constant pressure in the gas phase layer by using a pressure forming gas injected into the cylinder, even if the pressure of the LPG fuel stored in the cylinder at a low temperature in winter, the liquid LPG fuel from the liquid layer to the engine Supply smoothly.

Accordingly, the present invention can improve the winter startability and restartability of the gas fuel vehicle.

In addition, the cylinder 10 includes a multi-valve 30 for discharging the gaseous fuel charged in the cylinder 10 by the pumping pressure of the fuel pump and a filling valve 20 for filling the gaseous fuel through the fuel inlet 22. ) Is provided.

Filling valve 20 is a cylinder 21 from the fuel inlet 22 and the fuel inlet 22 is coupled to one side of the housing 21 is mounted to protrude out of the cylinder 10, the fuel inlet 22 is injected by filling the external gas fuel 10 is provided with a filling pipe 23 connected to a position C lower than the oil level D of the gaseous fuel stored therein.

The housing 21 is fixed to the cylinder 20 by inserting a packing in the middle to maintain the airtightness of the cylinder 10.

As shown in FIG. 2, the liquid discharge port 24 formed at the tip of the filling pipe 23 is installed at a position C close to the lower end of the inner space of the cylinder 21 so as to fill the gas fuel in the liquid layer.

Therefore, the liquid discharge port 24 is located at a position C lower than the oil level D of the gaseous fuel filled in the cylinder 21.

On the other hand, the gas discharge port 25 is formed on the filling pipe 23 to inject some of the gaseous fuel injected through the filling pipe 23 into the gas phase layer.

The gas phase discharge port 25 is formed at a position E near the upper end of the filling pipe 23 to inject the gaseous fuel in the liquid state into the gas phase layer.

In this way, as the gas fuel injected through the gas phase outlet 25 vaporizes in the gas phase layer and falls downward, the temperature and pressure of the gas phase layer are lowered.

That is, the present invention injects a part of the gaseous fuel into the gas phase layer through the gas phase discharge port while simultaneously filling the gaseous fuel through the liquid phase discharge port.

At this time, the fuel oil level rises as the gas fuel is directly charged into the liquid phase, and a part of the gas fuel is injected into the gas phase layer through the gas discharge port to reduce the temperature and pressure of the gas phase layer.

Accordingly, the present invention compensates the pressure increase amount of the gas phase layer by filling the liquid phase layer and gaseous fuel in the gas phase layer to offset the pressure reduction amount of the gas phase layer due to the decrease in the temperature of the gas phase layer to maintain a constant pressure inside the cylinder. It is possible to prevent the filling delay of the gaseous fuel due to the excessive pressure rise in the bed.

According to the experimental value, the diameter of the filling pipe 23 is preferably about 15 mm, and the diameter of the gas phase outlet 25 is 2 mm so that the pressure in the gas phase layer can be kept constant.

In addition, the filling valve 20 is preferably provided with a safety valve and a manual valve (not shown) installed on the outside of the housing 21.

In addition, the filling valve 20 is a float for detecting the filling amount of the overcharge prevention valve (not shown) and the LPG fuel (F) to prevent the pressure inside the cylinder 10 is excessively increased by the LPG fuel (F) ( It may be further provided with a drawing).

Next, a fuel charging method of a fuel tank for a gas fuel vehicle according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 5.

As shown in FIG. 5, the pressure forming gas G is injected through the fuel injection port 22 to form a predetermined pressure for discharging the LPG fuel F in the cylinder 10 (S11).

At this time, in order to maintain the pressure inside the cylinder 10 between the preset maximum pressure and the minimum pressure, as shown in FIGS. 3 and 4, the pressure forming gas G is about 0.2 to the value calculated by Equation 1. Injected by 0.5 bar.

Subsequently, injection of gaseous fuel is started through the fuel injection port 22 (S11).

Then, fuel is injected into the cylinder 11 through the filling pipe 23 connected to the fuel inlet 22. (S12)

In detail, the liquid discharge port 24 formed at the tip of the filling pipe 23 is installed near the lower end of the cylinder 10 internal space, so that the oil surface D of the gaseous fuel filled in the cylinder 10 is filled. It is located at a lower position (C).

Therefore, the gaseous fuel injected through the liquid discharge port 24 is rapidly filled in the liquid layer in the cylinder 10.

On the other hand, the gaseous discharge port 25 formed in the upper portion of the filling pipe 23 so as to be close to the upper end of the cylinder 10 inner space injects a portion of the gaseous fuel to the gas phase layer.

At this time, the gas fuel injected through the gas phase outlet 25 reduces the temperature and pressure of the gas phase layer while vaporizing in the gas phase layer.

On the other hand, the diameter of the liquid discharge port 24 and the gas phase discharge port 25 is the increase in the pressure of the gas phase layer according to the rise of the surface of the liquid layer during the simultaneous filling of the liquid layer and the gas phase layer and the amount of pressure reduction of the gas phase layer due to the gas phase layer injection of the gaseous fuel It is set to match.

For example, the diameter of the liquid discharge port 24 is about 15 mm, and the diameter of the gas phase discharge port 25 is preferably about 2 mm.

Therefore, as the pressure increase amount and the pressure decrease amount of the gas phase layer are canceled, the pressure inside the cylinder 10 is kept constant (S14).

Accordingly, the present invention can prevent the fuel charge delay phenomenon due to excessive pressure rise of the gas phase layer formed inside the cylinder during gas fuel filling.

In particular, the present invention is to maintain the pressure inside the cylinder at the time of filling the gas fuel to maintain the discharge pressure of the gas fuel discharged from the fuel tank to the fuel line at a constant level to eliminate the engine relief and starting off due to the discharge pressure drop can do.

Through the above-described process, the present invention forms a constant pressure by injecting the pressure forming gas into the cylinder, even if the pressure of the LPG fuel drops in the cold state in winter, the liquid formed by the pressure formed by the pressure forming gas LPG fuel can be smoothly supplied to the engine.

The scope of the present invention is not limited to the embodiments described above, but is defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self evident.

10: cylinder 11: bracket
20: filling valve 21: housing
22: fuel inlet 23: filling pipe
24: liquid discharge port 25: gas phase discharge port
30: Multivalve F: LPG Fuel
G: pressure forming gas

Claims (7)

Bombs formed of high-pressure vessels forced to protect gas fuel stored therein from shocks or vibrations;
A pressure forming gas injected to form a predetermined pressure inside the bomb,
The pressure forming gas is a fuel tank for a gas fuel vehicle, characterized in that injected before the first injection of gaseous fuel. The method of claim 1, wherein the pressure forming gas
A fuel tank for a gas fuel vehicle, which is nitrogen or an inert gas. The method of claim 1, wherein the pressure forming gas
Fuel tank for a gas fuel vehicle, characterized in that the gas lighter than the gas fuel. The method of claim 1, wherein the pressure forming gas
The fuel tank for a gas fuel vehicle, characterized in that the gas fuel is filled in the cylinder and injected at a pressure between a preset maximum pressure and a minimum pressure of the remaining space. The method according to any one of claims 1 to 4,
The fuel tank is filled with a filling valve for injecting gas fuel into the cylinder and
It is provided with a multi-valve for discharging the gas fuel filled in the cylinder,
The filling valve is a housing which protrudes to the outside of the cylinder,
A fuel inlet coupled to one side of the housing and injecting and filling gas fuel from an outside;
And a filling pipe connected to the position close to the lower end of the bomb inner space from the fuel inlet,
The filling pipe includes a liquid discharge port formed at the tip of the filling pipe so as to be close to the lower end of the cylinder inner space;
A fuel tank for a gas fuel vehicle, characterized in that the gaseous discharge port is formed in the upper portion of the filling pipe to be close to the upper end of the cylinder inner space. (a) injecting a pressure forming gas into the bombe,
(b) injecting gaseous fuel through a fuel inlet into the cylinder into which the pressure forming gas is injected in step (a); and
(c) charging the gaseous fuel injected in the step (b) into the cylinder through a filling pipe connected to the fuel inlet,
In the step (a), the pressure forming gas is
A fuel charging method of a fuel tank for a gas vehicle, characterized in that the injection into the pressure between the maximum pressure inside the cylinder and a predetermined minimum pressure. The method of claim 6, wherein step (b)
Gas fuel vehicle for filling the gas fuel through the gas discharge outlet formed in the upper portion of the filling pipe to be close to the upper end of the cylinder inner space and the liquid discharge hole formed in the lower portion of the filling pipe so as to approach the lower end of the cylinder inner circumference How to fill fuel in fuel tank.

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