CROSS REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of Korean Patent Application No. 10-2019-0116549, filed on Sep. 23, 2019, which is hereby incorporated by reference in its entirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a system supplying fuel to a fuel consuming device from a fuel storage device in an aerial vehicle.

2. Description of Related Art

There has been a continuing need for a fuel transfer/supply system capable of continuously transferring fuel to a propulsion system irrespective of the changes of the attitude and acceleration of an aerial vehicle in flight.

In an existing fuel supply system, a method of transferring fuel by using an electric pump, a method of transferring fuel by pressure increased by pressurizing a fixed tank of storing fuel by using gas, and a method of transferring fuel by using these two methods combined together have generally been applied.

However, according to such fuel transfer methods, fuel does not reach a pump or an inlet of a transfer pipe in an environment in which the position of fuel is changed according to the changes of the attitude and acceleration of an aerial vehicle. Accordingly, there is a problem that fuel transfer is stopped or pressurizing gas is transferred instead of the fuel. Eventually, if this happens, the fuel supply is interrupted and flight is not maintained.

In order to solve the above problems, a method of supplying fuel by storing the fuel in a variable tank which can be changed in volume may be considered.

In such a method, the variable tank, which can contract and expand, is mounted in the fixed tank, fuel is stored in the variable tank to completely fill the variable tank without bubbles, and during flight, the fuel is squeezed out by pressurizing the outside of the variable tank to be transferred. In a system using this method, the variable tank is located between fuel and pressurizing gas, fundamentally blocking the pressurizing gas from mixing with the fuel. Accordingly, the gas may be prevented from being transferred during the fuel transfer, and the fuel transfer may be prevented from being interrupted even when the acceleration or attitude of an aerial vehicle is changed.

However, there is a constraint that the configuration of the inside of the fixed tank is required to be simplified since the variable tank is required to be operated by storing all fuel only in the variable tank. Furthermore, to prevent the damage of the variable tank in operation, sharp structures are required to be absent in the fixed tank, and the structural design of the fixed tank is needed to ensure that a fixed tank structure does not interfere with the variable tank during the contraction of variable tank. In addition, since the variable tank is required to be mounted inside the fixed tank, weight increase and fuel loading capacity decrease occur. Accordingly, the design of a fuel transfer system is limited. Furthermore, the fuel loading capacity is also limited.

The matters described in the related art are provided to facilitate the understanding of the background of the present invention, and may include matters that are not known to those skilled in the art.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to solve the problems and an object of the present invention is to propose a fuel supply system for an aerial vehicle, wherein continuous fuel supply is performed despite the change of the attitude or acceleration of an aerial vehicle, sufficient fuel is stored, and constraints on fuel tank design are minimized.

In order to achieve the objectives of the present invention, according to one aspect of the present invention, there is provided a fuel supply system for an aerial vehicle, the system including: a plurality of fixed tanks storing fuel; a variable tank provided in a fixed tank of the plurality of fixed tanks and storing fuel; a fuel supply flow path, a first end of which is connected to the variable tank and passing through the plurality of fixed tanks; and a fuel pump provided in a fixed tank which does not have the variable tank, an outlet side of the fuel pump being connected to the fuel supply flow path.

In addition, when the fuel contained in the fixed tank which does not have the variable tank is supplied to the fuel supply flow path by operation of the fuel pump, the fuel contained in the variable tank may not be supplied to the fuel supply flow path.

Furthermore, a first fuel control valve may be provided in the fuel supply flow path at a front side of the fuel pump so as to control fuel supply from the variable tank.

In addition, during the fuel supply from the variable tank, fuel may be refilled to the variable tank by a fuel refilling means.

Furthermore, a pressure discharge valve may be provided in the fixed tank having the variable tank, and pressure of the fixed tank may be discharged to the outside via the pressure discharge valve when refilling the variable tank with fuel.

Additionally, the fuel supply system may further include a pressurizing tank storing pressurizing gas to pressurize the plurality of fixed tanks.

In addition, the fuel supply system may further include a pressurizing flow path connected to the plurality of fixed tanks from the pressurizing tank; and a plurality of pressure control valves provided in the pressurizing flow path at locations inside the plurality of fixed tanks, respectively.

Here, control pressures of the plurality pressure control valves may be different from each other.

In addition, a high-pressure pump may be provided in the fuel supply flow path at a location outside the fixed tanks, the high-pressure pump supplying fluid to the fuel pump through the fuel supply flow path connected thereto.

Next, according to another aspect of the present invention, there is provided the fuel supply system for an aerial vehicle, the system including: the variable tank and the fixed tank in which fuel is stored; the fuel supply flow path connected to a fuel consuming device from the variable tank; and the fuel pump provided in the fixed tank, the outlet side of the fuel pump being connected to the fuel supply flow path, wherein the fuel stored in the variable tank or the fixed tank is selectively supplied to the fuel consuming device.

Here, a discharge fuel quantity of the fuel pump may be greater than a sum of a fuel quantity required at the fuel consuming device and a fuel quantity making discharge of the fuel contained in the variable tank to the fuel supply flow path unnecessary.

According to the fuel supply system for an aerial vehicle of the present invention, continuous fuel supply from the variable tank is performed despite the change of the attitude or acceleration of the aerial vehicle and the fixed tank is also used. Accordingly, sufficient fuel can be stored and constraints on fuel tank design can be minimized.

