SE534065C2 - Fuel system with compressed air venturi tube for transferring fuel between two tanks and a vehicle comprising said fuel system - Google Patents

Description

A hose whose opposite end is located in the main tank is connected so that fuel is thereby sucked from the main tank and mixed with the return fuel in the venturi tube before it is led out into the smaller container / tank. In this way the fuel level is kept constantly high in the smaller tank / tank and a reliable continuous fl flow of fuel from the tank / tank to the engine can be ensured.

However, this type of fuel system requires a relatively large and continuous fl return of fuel to generate the necessary transfer of fuel from the main tank to the smaller tank / tank, and in the event of an interruption or too small fl failure, sufficient transfer of fuel will not be possible.

There is thus a need for a more reliable transfer of fuel from the main tank to the smaller container / tank.

A more reliable transmission can be obtained by driving the venturi tube instead of being driven by the varying flow of return fuel from the engine by means of compressed air.

An advantage of such a solution is that it is very easy to modify, and thereby improve, existing fuel systems as only some components to supply compressed air to the venturi need to be supplied to the existing system and thereby obtain an improved system.

Another advantage of such a fuel system is that it does not result in any temperature increase of the fuel in the secondary tank, which inevitably occurs in existing solutions where heated return fuel from the engine is used to drive the fuel transfer from the main tank to the secondary tank. Summary of the Invention The present invention has for its object to provide an improved fuel system. The object is achieved by a fuel system according to the independent patent claim.

According to the invention, a venting unit is arranged at a suitable place along the second line through which fuel / air is transported, where at least a part of the air which is supplied to the venturi and thereby flows in the line is diverted from the fuel. This embodiment can be used in combination with the previous solution for deaeration or as a separate solution to avoid overpressure in the smaller tank. This embodiment also has the advantage that the risk of foaming in the smaller tank is reduced when at least a part of the air in the fuel / air mixture is removed before it flows into the secondary tank.

According to the invention, a compressed air hose leads the air to the venturi tube and along the compressed air hose a valve is arranged with which the air flow through the compressed air hose can be controlled. This embodiment thus makes it possible to control the amount of fuel transferred from the main tank to the secondary tank.

The venturi has a section with a reduced cross-sectional area and that the first pipe connects to this section. This embodiment results in a fuel system that is easy to manufacture, assemble and place in a vehicle.

The invention also relates to a vehicle comprising any of the fuel systems described above. l0 15 20 25 30 534 065 4 In one embodiment, compressed air is led from a dangerous system in the vehicle to the fuel system's venturi. This embodiment means that no separate additional arrangement for supplying compressed air to the fuel system needs to be installed in the vehicle.

In one embodiment, the compressed air to the vehicle's fuel system is directed from a braking system including a compressor to the venturi. This is an advantageous embodiment as the vehicle does not need to be provided with additional systems, but a system already existing in the vehicle can be used.

Brief description of the invention The invention is explained in more detail below with reference to the embodiment of the invention shown in the drawing figures, where: Figure 1 shows the fuel system according to the invention schematically.

Figure 2 schematically shows an embodiment of a venturi.

Detailed Description of the Invention Figure 1 shows an embodiment of the fuel system 10 as defined by the claims. The fuel system is intended to be used to continuously and reliably supply an internal combustion engine 11 with the desired amount of fuel. The fuel system comprises a main tank 12 in which fuel is filled and stored. The main tank 12 has a volume that provides the desired range and satisfactory refueling intervals.

The volume is thus adjusted based on what the internal combustion engine 1 1 is installed in for the type of vehicle, as well as the fuel consumption of the engine 11.

The main tank 12 has a suitable geometric shape based on the available space, as well as the desired volume.

If large fuel volumes are required or desired, alternatively if the available space for the main tank 12 is limited, the vehicle 10 may include interconnected fuel tanks to thereby increase the total volume and enable better use of available space.

The fuel system also includes a secondary tank 13. Fuel is transferred from the main tank 12, or tanks, continuously to the secondary tank 13 so that the fuel level in this tank during use of the vehicle is always kept at a higher level than the level in the main tank 12. This is to ensure sufficient fuel in the secondary tank 13 to continuously meet the periodically high fuel needs of the engine 11. In the embodiment shown in Figure 1, the secondary tank 13 consists of a space separated from the main tank 12 and integrated in the main tank 12. The wall 14 delimiting the secondary tank 13 from the main tank 12 has an opening 15 so that when the desired fuel level is reached in the secondary tank 13, i.e. when the fuel level reaches the lower edge of the opening 15, the fuel in the secondary tank 13 is drained back to the main tank 12 through the opening 15. important to avoid overfilling of fuel in the secondary tank 13 as this can result in leakage from connections and the like in the secondary tank 13.

However, the secondary tank may alternatively consist of a separate tank placed separately from the main tank. The secondary tank must then be provided with some type of drainage back to the main tank to avoid overfilling of the secondary tank.

Both the main tank 12 and the secondary tank 13 can have different geometric shapes depending on the available space in the intended vehicle. However, the main tank 12 preferably has a shape which facilitates as complete emptying of the main tank 12 as possible while the shape of the secondary tank 13 is suitably such that the fuel in the tank is conveyed to the area where the fuel is transferred to the engine 11, for example by have a bottom with surfaces sloping towards this area so that the fuel accumulates in the desired place in the secondary tank 13.

The fuel is transferred from the main tank 12 to the secondary tank 13 via a first line 16 one end 17 of which opens near the bottom 18 of the main tank 12 to ensure that as much of the fuel in the main tank 12 as possible can be utilized and transferred to the secondary tank 13.

For the transfer of fuel from the main tank 12 to the secondary tank 13, a venturi tube 20 is used, the venturi tube 20 comprises, as shown in Figure 2, a substantially straight through passage 21 which has a section 22 with considerably reduced cross-sectional area. The reduced area then gives a flow through the passage 21 giving rise to an increased flow rate through the section 22 which in turn generates a suction force in the first conduit 16 (fi gur 1) whose second end 19 is connected to the section 22 with reduced cross-sectional area. The suction force generated in the first line 16 causes the fuel to be carried from the main tank 12 to the venturi tube 20 where it is mixed with the fluid, in this case air, which flows through the passage 21 and further via a second line 23 which opens into the secondary tank 13.

In the fuel system 10 shown in Figure 1, pressurized air is fed from a compressor 32 to the venturi tube 20 via a compressed air hose 24. The fuel from the main tank 12 is thus mixed with the pressurized air in the passage 21 of the venturi tube 20 and the fuel / air mixture is led to the secondary tank 13 via the second line 23.

The air in the fuel must be separated from the fuel before the fuel is transferred to the engine 11 to ensure the desired function of the engine 11. This can be done either in the secondary tank 13 which is provided with a vent valve (not shown) to avoid overpressure in the tank. great risks of breakdowns because considerable amounts of air flow together with the fuel to the tank.

Deaeration can alternatively take place by means of a deaeration unit 30 which is located in a suitable place along the second line 23 in order to separate as much air as possible from the fuel before it reaches the secondary tank 13. A combination of these two solutions is preferred even if they provide desired effect separately. The deaeration unit 30 comprises a filter which separates the air from the fuel.

Fuel is finally fed from the secondary tank 13 to the internal combustion engine 11 via a fuel line 25, one end 26 of which is suitably located near the bottom 27 of the secondary tank 13 while the other end is connected to the engine 11.

The fuel systems 10 shown in Figures 1 and 2 also include a valve 31 arranged at a suitable location along the compressed air line 24. The valve 31 makes it possible to control the compressed air flow to the venturi tube 20, and thus also the amount of fuel transferred from the main tank 12 to the secondary tank 13. the valve 31 is preferably designed in relation to, for example, the current throttle for the engine as it affects the engine's fuel consumption.

The fuel system 10 according to the invention is suitably arranged in a vehicle, for example a truck. Main tank 12, or main tanks, are then arranged in suitable places in the vehicle. Many vehicles include one or more compressed air systems as some of the functions of these vehicles are powered by compressed air generated by an engine compressor 32. An example of compressed air driven systems is the braking system 33 of trucks. Compressed air can then be led from this existing system to the venturi 20 and thereby be used for the desired transfer of the fuel from the main tank 12 to the secondary tank 13. 534 065 8 The invention has been described above on the basis of a preferred embodiment, but a number of modifications are conceivable: can be varied to suit certain specific conditions; 5 - The design of the tanks in terms of shape and mutual size ratio can be varied and adapted based on the vehicle in which the system is used and the desired properties of the system.

Pressurized gases other than air can be used. Although the invention has been described on the basis of some exemplary embodiments, the invention is not limited thereto but is based on the appended claims.

Claims (1)

534 065 PATENT REQUIREMENTS A fuel system (10) for supplying an internal combustion engine (11) with fuel, the system comprising: at least one main tank (12) for storing fuel; a secondary tank (13) to which fuel is transferred from the main tank (12) and from which fuel is led via a fuel hose (25) to the internal combustion engine (1 1); a venturi (20) intended for transferring fuel from the main tank (12) to the secondary tank (13), the transfer of fuel from the main tank (12) to the secondary tank (13) being obtained by passing compressed air through the venturi (20) and thereby generating a suction force in a first conduit (16) one end (17) of which is located in the main tank (12) and the second connected to the venturi (20) so that the fuel in the main tank is sucked through the first conduit (16) to the venturi where it mixes with the compressed air and is led to the secondary tank (13) via a second line (23) characterized in that a compressed air hose (24) conducts compressed air from a compressor (32) to the venturi tube (20) and that a valve (31) is arranged along the compressed air hose (24) with which The flow through the compressed air hose (24) can be controlled, thereby also controlling the transfer of the amount of fuel from the main tank (12) to the secondary tank (13) and that a venting unit (30) is arranged in a suitable place along the second line (23). ) where at least a portion of the air flowing in the conduit (23) is diverted from the fuel. . Fuel system according to claim 1, characterized in that the secondary tank (13) is either an integral part of the main tank (12), or a separate tank placed separately from the main tank (12). 10 15 534 065 10. Fuel system according to one of the preceding claims, characterized in that the venturi tube (20) has a section (22) with a reduced cross-sectional area and that the first line (16) connects to this section (22). . Vehicle comprising a fuel system according to any one of claims 1 - 3.. Vehicle according to claim 4, characterized in that the compressed air is led from an existing system in the vehicle to the fuel system (10). . Vehicle according to claim 5, characterized in that the compressed air to the fuel system (10) is led from a braking system (33) comprising a compressor (32) to the venturi tube (20).