Technical Field of the Invention

The present invention relates to a fuel system with a pressure regulator, which eliminates the breakdowns experienced in the fuel pump and the fuel system due to decreasing open air pressure, especially in high altitude areas, by means of the pressure regulator integrated into the fuel tank.

Prior Art

The fuel required for running the engine in motor vehicles is provided by the fuel system. The fuel system provides the engine with the air and fuel mixture which is ideal for combustion. The fuel used for running the vehicle is stored in the fuel tank present in the vehicle. The fuel tank can have various dimensions and characteristics depending on the type of the engine, the characteristics of the vehicle and the volume of the engine. A fuel line is located between the fuel tank and the engine. When the vehicle requires fuel, the fuel pump draws the fuel inside the tank and delivers it to the engine after mixing said fuel with air over the fuel line. The engine, on the other hand, converts the fuel into motional energy by combustion. Parts such as the fuel tank, the fuel pump and the fuel line are among the important elements of the fuel system. Pressure drops over the fuel line and open air pressure are among the crucial factors affecting the suction of the fuel pump in internal combustion engines. Fuel pumps have a certain suction capability and suction becomes easier as ambient pressure increases, and becomes harder as said pressure decreases. Since the atmospheric pressure changes depending on the altitude of the area where the vehicle is used, the suction of the fuel pump decreases in high altitude areas where atmospheric pressure is lower. The decrease in open air pressure in particularly high altitude areas affects the operation of the fuel pump negatively and can even lead to a breakdown of the fuel pump due to the open air pressure decrease. The technical problem encountered due to the pressure decrease in higher altitudes can also cause the traction and the performance of the vehicle to be reduced. Moreover, when a pressure decrease is experienced in the fuel line, significant problems occur during the suction of the fuel pump and the delivery of fuel to the engine. Another technical problem encountered in fuel systems is the decrease of open air pressure. For vehicles which are used in higher altitudes, certain solutions are provided to prevent breakdowns due to open air pressure. In one of the methods employed for eliminating the breakdowns related to higher altitudes, an electric pump is added inside the fuel tank or to the fuel line before the fuel pump. Placing an additional pump inside the fuel tank or on the fuel line increases the costs of the vehicle and can lead to packaging problems. Also, the high flow rate fuel delivery, required particularly by heavy commercial vehicles may not be provided by this solution.

Another solution utilized in eliminating breakdowns due to high altitudes is to increase the suction capacity of the pump which provides suction from the fuel tank. In said solution, the characteristics of the fuel filter should be improved together with those of the fuel pump. The problem may be eliminated by increasing the capacity of the pump providing the suction. However this leads to other problems and breakdowns. Parasitic loads on the engine increase and the overall efficiency of the engine decreases.

Yet another solution utilized in eliminating breakdowns due to high altitudes is to feed the fuel returning to the fuel tank from the fuel pump or the fuel return line, back to the fuel pump. Feeding the pump with the returning fuel leads to the problem of heated fuel. The fuel entering the pump needs to be below a certain temperature limit; otherwise this causes the pump to be damaged. International patent document no: WO2007056911, which is present in the known art, describes a fuel tank design. In said fuel tank, the pressure is increased with air in order to reduce the strain on the fuel pump. Japanese patent document no: JPS61108864, which is present in the known art, tries to increase pressure by delivering pressurized air to the fuel tank.

The present patent application enables the pressure inside the fuel tank to be regulated as preferred, by means of a pressure regulator placed on the top of the fuel tank or inside the fuel tank. The pressure regulator integrated into the fuel tank controls the pressure level in the fuel tank and prevents high or low pressure from occurring. The present fuel system regulates the inner pressure of the fuel tank depending on the changes in open air pressure or any pressure change over the fuel line and thus, solves the problems related to pressure changes.

Thanks to the solution provided by the present patent application, it is no longer required to add a pump to the fuel systems or to increase the capacity of the existing fuel pump. An additional pressure regulator added to the fuel tank solves the pressure problems which may occur in the fuel system. The vehicles having the fuel system of the present application can be operated in areas with various altitudes and high altitudes without any problems.

Objectives of the Invention The objective of the present invention is to provide a fuel system with a pressure regulator aimed to eliminate traction and performance problems related to the decrease in the open air pressure in high altitude areas.

Another objective of the present invention is to provide a fuel system with a pressure regulator which is not affected by the altitude of the area where the vehicle is used, which can operate on the basis of open air pressure or sea level pressure in any area.

Yet another objective of the present invention is to provide a fuel system with a pressure regulator which solves the breakdowns experienced in the fuel pump in high altitude areas without changing the existing vehicle design and without incurring additional costs.

Brief Description of the Invention

The fuel system with a pressure regulator, defined in the first claim provided to meet the objective of the invention and in the other claims related to the first claim, comprises a fuel pump, a fuel line, an air line, a fuel tank and a pressure regulator integrated into the fuel tank. The pressure regulator is integrated into or onto the fuel tank. The pressure regulator regulates the pressure inside the fuel tank via pressurized air obtained from the vehicle air line. The measuring sensor inside the pressure regulator constantly measures the inner pressure of the fuel tank. In the event of a pressure decrease (drop) inside the fuel tank, the pressure regulator directs the air it controls into the fuel tank, thereby increasing the pressure inside the tank to the desired level. The pressure regulator also checks the fuel line pressure. In case a pressure loss occurs over the fuel line, the pressure inside the fuel tank is increased in order to enable the fuel pump to perform suction more easily. By means of the pressure regulator integrated into the fuel tank, even if the atmospheric pressure in the area where the vehicle is operated changes, the fuel system is not affected by said pressure change and will continue to operate as if it is on normal sea level. Thus, the performance of the fuel pump is improved by a pressure regulator integrated only to the fuel tank and the air line controlled by said regulator. Detailed Description of the Invention

The fuel system with a pressure regulator provided to meet the objectives of the present invention is illustrated in the attached figures, where;

Figure 1 . A schematic view of the fuel system with a pressure regulator.

The parts shown in the figures are enumerated separately, and the numbers correspond to the following.

1. Fuel system with a pressure regulator

2. Fuel tank

3. Fuel line

4. Float

5. Hole

6. Air source

7. Air line

8. Fuel pump

9. Pressure regulator

91. Measuring sensor

M. Engine

The fuel system (1) with a pressure regulator used in motor vehicles, which enables the air pressure inside the motor vehicle (2) to be equalized to the open air pressure in all cases, comprises;

-at least one fuel tank (2) which is present in the vehicle and where fuel is stored, -at least one fuel line (3) between the fuel tank (2) and the engine (M), where the fuel inside the fuel tank (2) passes through to be delivered to the engine (M), -at least one float (4) which is inside or on top of the fuel tank (2) and which enables the fuel level inside the fuel tank (2) to be measured, -at least one hole (5) on the fuel tank (2),

-at least one air source (6) which provides air at the preferred pressure and which is preferably one of the existing parts of the vehicle,

-at least one fuel pump (8) which draws the fuel from the fuel tank (2) and directs it to the engine (M) through the fuel line (3),

-at least one pressure regulator (9), which is located on or inside the fuel tank (2), which measures the inner pressure of the fuel tank (2), which, when the inner pressure of the fuel tank (2) drops below the desired level, directs the pressurized air coming from the air line (7) to the fuel tank (2), thereby regulating the inner pressure level of the fuel tank (2).

The fuel system (1) with pressure regulator of the present invention, measures the open air pressure of the area where the vehicle is operated and/or the pressure change in the fuel tank (2) related to the open air pressure, and regulates the inner pressure of the fuel tank (2). In vehicles utilizing the fuel system (1) with pressure regulator, the operation of the fuel pump (8) does not change whether the vehicle is used in areas with higher or lower open air pressure as the inner pressure of the fuel tank (2) is regulated according to the changes in the atmospheric pressure. Thus, the vehicles using the fuel system (1) with pressure regulator exhibit the same traction and performance regardless of the open air pressure.

In the fuel system (1) with pressure regulator, the fuel required for the vehicle to operate and move is stored inside the fuel tank (2). A float (4) is present inside or on top of the fuel tank (2). The float (4) measures the fuel level inside the fuel tank (2) and transmits the fuel level to the electronic system of the vehicle. Preferably, at least one hole (5) is present on the fuel tank (2). The hole (5) is preferably located on the top portion of the fuel tank (2) and equalizes the pressure of the fuel tank (2) with the open air pressure. The hole (5) located on the fuel tank (2) allows the excess pressure to be removed from the fuel tank (2) when overpressure develops inside the fuel tank (2). When the vehicle is used in an area such as the sea level, where the open air pressure is approximately 1 atmosphere, the hole (5) equalizes the fuel tank (2) pressure to 1 atmosphere as it opens up to the open air. In this case, it is not required to use the pressure regulator (9).

In the fuel system (1) with pressure regulator of the present invention, the fuel inside the fuel tank (2) is sucked by the fuel pump (8) to be directed to the engine (M) through the fuel line (3). As the suction of the fuel from the fuel tank (2) to be delivered to the engine (M) for combustion is provided by the fuel pump (8), the operation of the fuel pump (8) and its ability to perform complete suction directly affects the combustion inside the engine (M) and the engine (M) performance.

In an embodiment of the invention, the fuel system (1) with pressure regulator comprises at least one air source (6). The air source (6) provides the air to be used in the fuel system (1). A device such as a compressor or a fan, which provides air, may be used as the air source (6). The air provided by the air source (6) is delivered to the pressure regulator (9) through the air line (7).

In a preferred embodiment of the invention, the air source (6) is an existing air source (6) which is already being used in the vehicle. Any air source (6) in the vehicle can be connected with the air line (7) to feed the pressure regulator (9).

In a preferred embodiment of the invention, a pressure regulator (9) is located on the fuel tank (2). Preferably, the pressure regulator (9) comprises at least one air inlet and at least one air outlet. The air coming from the air line (7) is connected to the pressure regulator (9), preferably to the air inlet of the pressure regulator (9). The pressure regulator (9) can direct the air coming from the air line (7) preferably through the air outlet and deliver it inside the fuel tank (2). An air outlet of the pressure regulator (9) is connected to the fuel tank (2). When high pressure develops inside the fuel tank (2), the pressure regulator (9) will deliver the air inside the fuel tank (2) to the external environment through the air outlet. In an embodiment of the invention, the pressure regulator (9) is positioned to completely cover the float (4).

In an embodiment of the invention, the pressure regulator (9) can operate in two directions. The pressure regulator (9) can direct the air coming from the air line (7) to the fuel tank (2) and can also remove the pressurized air from the fuel tank (2) when high pressure develops in the fuel tank (2). By means of the bidirectional operation of the pressure regulator (9), air can be directed towards the fuel tank (2) and the pressurized air inside the fuel tank (2) can be directed outside said tank (2) if necessary.

In an embodiment of the invention, the pressure regulator (9) is connected to an air line (7) carrying air with approximately 1 bar (1 atmosphere) pressure. The pressure regulator (9) directs the air coming from the air line (7) at 1 bar pressure to the fuel tank (2). When air flows from the air line (7) at a different pressure, said air flow is not allowed to pass.

In another embodiment of the invention, the pressure regulator measures the pressure of the air coming from the air line (7) and adjusts the incoming air pressure to a pressure value of 1 bar. In this case, the pressure regulator (9) can be connected with an air flow which has a pressure level other than 1 bar.

In a preferred embodiment of the invention, the pressure regulator (9) comprises at least one measuring sensor (91). The measuring sensor (91) is a detector which can measure pressure and can detect the pressure level. In an embodiment of the invention, a measuring capsule which can detect pressure is used as the measuring sensor (91).

Preferably, the measuring sensor (91) measures the atmospheric pressure inside the fuel tank (2) or outside the fuel tank (2). In a preferred embodiment of the invention, the measuring sensor (91) is positioned to go inside the fuel tank (2) and measures the air pressure inside the fuel tank (2). In an embodiment of the invention, the measuring sensor (91) is located inside the pressure regulator (9) and measures the fuel tank (2) air pressure based on the air coming from the fuel tank (2) air line (7) connected to the pressure regulator (9).

In an embodiment of the invention, the pressure regulator (9) operates on the basis of the pressure value measured by the measuring sensor (91). When the measuring sensor (91) measures a pressure level inside the fuel tank (2) which is lower than the preferred pressure value (1 bar), the pressure regulator (9) directs pressurized air (at approximately 1 bar) from the air line (7) to the fuel tank (2). Thus the air pressure inside the fuel tank (2) is equalized with the open air pressure and the fuel pump (8) is brought back to the ideal operating range.

In an embodiment of the invention, when the measuring sensor (91) measures a pressure level inside the fuel tank (2) which is higher than the preferred pressure value (1 bar), the pressure regulator (9) opens the air outlet connected to the fuel tank (2), thereby directing the pressurized air inside the fuel tank (2) outside. Thus, when the air pressure inside the fuel tank (2) increases, the pressure regulator (9) reduces the high pressure to equalize it with the open air pressure and the fuel pump (8) is brought back to the ideal operating range.

The pressure regulator (9) constantly regulates the air pressure inside the fuel tank (2), thereby keeping it at the preferred open air pressure level. Since the pressure level inside the fuel tank (2) will constantly be regulated to equalize with the open air pressure, the fuel pump (8) operates at open air pressure level in all conditions, regardless of the altitude or elevation at which the vehicle is being operated. The pressure regulator (9) also operates in cases of pressure drops related to the lines and connections on the fuel system (1) with the pressure regulator. In an embodiment of the invention, a balancing valve which can operate in both directions is used as the pressure regulator (9). The pressure regulator (9) in the form of a valve can be connected to any air line on the vehicle. In an embodiment of the invention, the pressure regulator (9) regulates the pressure by utilizing the air flow it receives from the air line (7) with variable flow rate, so as to always keep the pressure inside the fuel tank (2) at the open air pressure at sea level. A hole (5), which is located on the fuel tank (2) and which allows for equalizing the open air pressure, is utilized in the fuel system (1) with pressure regulator of the present invention. Thus, the hole (5) acts as a safety measure and equalizes the fuel tank (2) pressure to the external pressure in cases where the pressure regulator (9) is not working. When the vehicle operates at open air pressure the hole (5) will equalize the air pressure and it will not be required for the pressure regulator (9) to operate

In an embodiment of the invention, the fuel system (1) with the pressure regulator operates as follows. The pressure regulator (9) is mounted on the fuel tank (2). Any of the air lines used in the vehicle is connected to the pressure regulator (9). The pressure regulator (9) operates in both directions. The measuring sensor (91) located inside the pressure regulator (9) measures the air pressure inside the fuel tank (2). The air pressure inside the fuel tank (2) is desired to be always at the open air pressure level. The pressure regulator (9) equalizes the pressure based on the measurements performed by the measuring sensor (91). When the measuring sensor (91) measures a level lower than the open air pressure, the pressure regulator (9) directs the air coming from the air line (7) to the fuel tank (2), thereby regulating the pressure inside the fuel tank (2) to be equal to the open air pressure. When the measuring sensor (91) measures a pressure inside the fuel tank (2) which is higher than the open air pressure, the pressure regulator (9) directs the air inside the fuel tank (2) to the external environment, thereby equalizing the pressure to the open air pressure.