Fuel tank having inlet check valve

The present disclosure relates to a fuel tank comprising a filling tube opening via an inlet check valve into the fuel tank and comprising a venting device for discharging fuel vapors from the fuel tank. According to the present disclosure, the venting device has at least one venting line, which extends into the interior of the fuel tank and opens with an open end into a gas volume in the region of an upper wall part of the fuel tank, wherein the at least one venting line is guided such that it forms a siphon in the region of a lower wall part, and the inlet check valve has a bypass connection, to which the at least one venting line is connected.

RELATED APPLICATIONS

This application is a 35 U.S.C. § 371 national phase application of International Application No. PCT/EP2016/075720, filed on Oct. 26, 2016, which claims the priority of German Patent Application DE 10 2015 221 227.0, filed Oct. 29, 2015, the contents of which are incorporated herein by reference in their entirety.

FIELD

The present disclosure relates to a fuel tank comprising a filling tube opening via an inlet check valve into the fuel tank and comprising a venting device for discharging fuel vapors from the fuel tank, and also a corresponding check valve.

BACKGROUND

Fuel tanks for vehicles typically have operational airing and venting, for example, to enable a pressure equalization of the tank interior with the surroundings during fill-up or in the event of temperature changes. Known systems use one or more valves for this purpose, so-called rollover valves (ROV), which are arranged penetrating different locations of the upper tank wall. The ROV additionally has or have the property of blocking in the event of a rollover of the vehicle, so that fuel cannot run out via the valve. It is considered to be disadvantageous to use of ROV since they represent a significant cost factor and they penetrate the tank wall, i.e., they require tank openings to be sealed.

SUMMARY

Proceeding therefrom, the present disclosure provides a fuel tank of the type mentioned at the outset comprising a simple and cost-effectively designed venting device.

It is provided according to the present disclosure that the venting device has at least one venting line, which extends into the interior of the fuel tank and opens with an open end into a gas volume in the region of an upper wall part of the fuel tank, wherein the at least one venting line is guided such that it forms a siphon in the region of a lower wall part, and the inlet check valve has a bypass connection, to which the at least one venting line is connected.

In one preferred embodiment of the present disclosure, two or more venting lines are provided, the open ends of which are arranged in the region of the upper wall part such that in any inclined position and any fill level of the fuel tank, at least one venting line opens into a gas volume.

An improvement of the pressure tightness of the venting device in the upside-down position can be achieved in that a valve, in particular a ball valve, is arranged at the open end of the at least one venting line, which valve is open in a normal position of the fuel tank and is closed in an upside-down position.

The inlet check valve according to the present disclosure has a bypass line which bypasses a check body of the inlet check valve, and to which the at least one venting line arranged in the fuel tank is connectable, and therefore it is in fluid communication with the filling tube.

DETAILED DESCRIPTION

Now, a preferred embodiment of the present disclosure will be described in conjunction with the accompanying drawings. The sizes, materials, and other specific numerical values in the following description of the embodiment are simply by way of examples for ease of understanding of the present disclosure and should not be construed to limit the present disclosure unless otherwise specified. Note that in the description and the drawings, components having substantially the same functions and configurations are designated by the same reference characters, so that their description is not repeated, while components not directly relevant to the present disclosure are not shown.

The fuel tank10shown inFIG. 1has a known venting device. It comprises two rollover valves (ROV)12,14, which are arranged in an upper wall part of the fuel tank10, and which communicate via lines16,18,20with a filling tube22, from which fuel vapors are supplied via a line24to an activated carbon filter26and from there to the engine. The filling tube opens via a conventional inlet check valve28, which is not part of the venting device, into the fuel tank10. The valves12,14are arranged far apart from one another, and therefore in an inclined position of the tank, at least one of the valves is not covered by liquid (comparable to the situation shown inFIGS. 4 and 7). The valves12,14protrude comparatively far into the interior of the fuel tank10. Since the valves12,14cannot be covered simultaneously by liquid fuel, a fill-up procedure is terminated by the shutoff valve30. The volume of the fuel tank therefore cannot be used optimally.

FIG. 2shows a first exemplary embodiment of the present disclosure, which can be implemented substantially more cost-effectively than the system ofFIG. 1. Rollover valves are not provided, and therefore corresponding openings in the tank wall are not required. Instead, a venting line32extending into the tank interior is provided, the open end of which is arranged in direct proximity to the upper housing wall, and the other end of which is connected to a bypass line at the inlet check valve34. The venting opening thus also communicates here with the filling tube22. It is arranged approximately in the middle of the fuel tank10, so that slightly inclined positions do not interfere with the venting function. Due to the venting line32, which extends far up to the tank wall, the fuel tank may also be filled up to a higher level, and therefore the use of the tank volume is improved in relation to the situation illustrated inFIG. 1. The venting line32is guided in a curve36forming a siphon in the vicinity of the lower wall part of the fuel tank10.

FIG. 3corresponds toFIG. 2, wherein two venting lines38,40are provided, however, the open ends of which are arranged approximately like the rollover valves12,14inFIG. 1. This ensures that in an inclined position, as shown inFIG. 4, at least one venting line opens into a gas volume. Like the venting line32, the venting lines38,40are also guided in a curve in the region of the lower housing wall.

InFIG. 5, the fuel tank ofFIGS. 3 and 4is in an upside-down position. The curves42,44of the venting lines38,40protrude beyond the liquid level and prevent liquid fuel from draining out via the venting lines due to fuel vapors enclosed therein. A very small quantity of liquid fuel cannot be prevented from entering the filling tube22via the lines38,40; however, due to the connection of the line24at a distance from the end of the filling tube22, i.e., the provision of a certain volume between the connection of the line24and the end of the filling tube22, it is ensured that no liquid fuel can enter the activated carbon filter via the line24, which is to be avoided in any case. Accordingly, the mentioned volume in the end region of the filling tube22has a function of a liquid separator.FIG. 6corresponds toFIG. 5, however, ball valves46,48are arranged here at the free ends of the venting lines38,40, which close in the upside-down position and thus ensure an improved pressure retention function.

FIGS. 7 and 8show a further exemplary embodiment comprising two venting lines50,52, which are guided such that curves54,56,58,60are formed both in the region of the lower wall part and also the upper wall part of the fuel tank10. The upper curves58,60are positioned in the vicinity of the open end of the respective other venting line50,52, and therefore they are located above the liquid level in the inclined position and prevent liquid from flowing out via the open end, which is then flooded.

FIG. 9shows an inlet check valve34, which has a connection part64for the connection to the filling tube22and a spring-loaded check flap66, which opens toward the tank interior during fill-up. Furthermore, the valve has a bypass line68, which bypasses the check flap, having a connection nipple for the at least one venting line, via which it is in fluid communication with the inlet tube.