Venting device for venting a motor vehicle tank

A ventilation device for ventilating a motor vehicle tank. The ventilation device includes a filler pipe, a ventilation line, a degassing line, and a guide arc member. The ventilation line is to be fluidically connected at a first ventilation line end to the motor vehicle tank, and at a second ventilation line end to the filler pipe via a ventilation inlet. The degassing line is to be fluidically connected at a first degassing line end to the filler pipe via a degassing outlet. The guide arc member is arranged in the filler pipe to define a guide path for incoming vapor passing through the ventilation inlet into the filler pipe. The guide arc member is to facilitate flow of the incoming vapor between an inner wall of the filler pipe and the guide arc member along a periphery of the filler pipe along a periphery of the filler pipe such that a gaseous component of the incoming vapor escapes through the degassing outlet and a liquid component of the incoming vapor flows off through the filler pipe.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority 35 U.S.C. § 119 to European Patent Publication No. EP 19174646.0 (filed on May 15, 2019), which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments relate to a ventilation device for ventilating a motor vehicle tank.

BACKGROUND

It is known to ventilate motor vehicle tanks, that is to say tanks in motor vehicles, in particular tanks for the fuel for propelling the motor vehicle, such as petrol or diesel fuel, by an operating ventilation during operation of the motor vehicle. The operating ventilation is generally realized at one or more highest points on the motor vehicle tank. The evacuated gas can be conducted into a fuel vapor filter, in particular an activated charcoal filter, in order to release the least possible hydrocarbons into the environment. For the refueling of the motor vehicle tank, a dedicated refueling ventilation system can be provided, wherein the gas released during the refueling ventilation is also conducted into the activated charcoal filter.

In order to avoid damage to the activated charcoal filter, it is known to separate the fuel vapor flowing in the ventilation lines via a liquid separator, so that liquid is separated off and can flow back into the tank and only gas makes its way to the activated charcoal filter. Such liquid separators can be arranged in the ventilation lines in the form of dedicated intermediate reservoirs. More recently, it has also been known to configure liquid separators directly in a connecting nipple of the filler pipe, so that separated-off liquid can make its way directly into the filler pipe and can flow off via the filler pipe. Separating nipples of this type require only a small installation space and the separated-off liquid can be easily led off.

From EP 1955888 A2, a liquid vapor separator for the fuel system of a vehicle is known, wherein the liquid vapor separator comprises a body having an inlet, which is connectable to a ventilation system of a fuel tank, and having a vapor outlet, which is connectable to a fuel vapor treatment device, and further comprises a condensation chamber for the condensation of fuel droplets, wherein the condensation chamber is fluidically connected to the inlet and the outlet, and wherein in the condensation chamber is arranged a droplet separator, which comprises a partition wall, and the condensation chamber extends on a filler neck of the fuel system.

During travel, and also in the course of so-called instant venting operations, for example for an immediate pressure reduction after actuation of a tank flap unlocking mechanism of a hybrid vehicle, in the ventilation system can arise excessive gas volume flows, which can also exhibit a high saturation of liquid fuel.

Known separating nozzles on the filler pipe can barely cope with higher gas volume flows of this kind, in particular due to the small operating volume of such separators. Too low a degree of separation can, however, lead to an increased loading, or even a destruction, of the fuel vapor filter, in particular, the activated charcoal filter.

SUMMARY

Embodiments relate to a ventilation device for ventilating a motor vehicle tank, which ventilation device functions reliably even under high gas volume flows, yet, at the same time, has a small installation space and low manufacturing costs.

In accordance with embodiments, a ventilation device for ventilating a motor vehicle tank, may comprise at least one of: a filler pipe; a ventilation line for fluidic connection at a first ventilation line end to the motor vehicle tank, and at a second ventilation line end opposite the first end, to the filler pipe via a ventilation inlet; and a degassing line for fluidic connection at a first degassing line end to the filler pipe via a degassing outlet; a guide arc arranged in the filler pipe and shaped to guide incoming vapor passing through the ventilation inlet into the filler pipe between an inner wall of the filler pipe and the guide arc along a periphery of the filler pipe, so that a gaseous component of the incoming vapor escapes through the degassing outlet and a liquid component of the incoming vapor flows off through the filler pipe.

In accordance with embodiments, the ventilation inlet is arranged to lay, in an installation position, at a top region of the filler pipe.

In accordance with embodiments, the degassing outlet is arranged to lay, in an installation position, at a top region of the filler pipe.

In accordance with embodiments, gas flow from a ventilation line, in particular, an operating ventilation line, for separating off the contained liquid is conducted to a filler pipe. However, separation is not realized in a connecting nipple on the filler pipe, but in the filler pipe itself. The greater volume of the filler pipe is therefore utilized as the operating volume for the separation. For this, the gas volume flow is guided via the ventilation line up to a ventilation inlet on the filler pipe, which, in the installation position, is configured at the top, so that the fuel vapor mixture can fall into the filler pipe.

In accordance with embodiments, the movement of the vapor is guided by a guide arc. The guide arc is a component having an arcuate or curvilinear cross-section to facilitate flow of vapor peripherally, substantially in a circular arc shape, through the cross-section of the filler pipe, in particular, of the filler head. In that way, only the gaseous component of the vapor rises to flow via the degassing outlet (i.e., an additional opening) which therefore is likewise, in the installation position, arranged at the top region, and onward via a degassing line. In that way, the vapor flows in the direction of a fuel vapor filter which may comprise an activated charcoal filter. The liquid fuel rises along the flow path defined by the guide arc to short of the degassing outlet and therefore runs off, via the filler pipe, in the direction towards the motor vehicle tank.

Due to the high operating volume, this ventilation device, even under high gas volume flows and with high liquid quantity, can achieve a reliable separation of liquid fuel and herein uses volumes and components of the filler pipe, so that the additional installation space and the manufacturing costs are low.

In accordance with embodiments defined in this patent disclosure, the terms “top” and “bottom” relate to the gravitational direction, so that, for instance, liquid falls from “top” to “bottom.”

In accordance with embodiments, a plurality of ribs are arranged on an outer wall of the guide arc that faces the inner wall of the filler pipe and configured for separating off the liquid. The ribs may be configured only on a portion of the guide arc, in particular, only on a first half of the guide arc that guides the entering vapor downwards.

In accordance with embodiments, the cross-section of the guide arc is preferably of substantially U-shaped or O-shaped configuration. The guide arc can be of multipart construction.

In accordance with embodiments, a moveable flap member is arranged in the filler pipe at the degassing outlet, so that, when a fuel-pump nozzle is introduced into the filler pipe, the flap member is moved by the fuel-pump nozzle in a closing direction. In that way, the overall area of the degassing outlet, during a refueling of the motor vehicle tank, is reduced or closed. During the refueling, vapor making its way through the ventilation inlet therefore flows off in full, or, for instance, except for a predefined quantity, only through the filler pipe.

In accordance with embodiments, the ventilation inlet and the degassing outlet are configured on a common connecting nipple on the filler pipe.

In accordance with embodiments, the guide arc is preferably configured on the common connecting nipple. In particular, the guide arc can be fastened to the connecting nipple, or the guide arc and the connecting nipple are configured as a one piece or unitary component.

Alternatively, in accordance with embodiments, the ventilation device can comprise a flow-guide for the positioning of a fuel-pump valve and for the guidance of a refueling flow, and the guide arc can be configured as a structural portion of the flow-guide.

In accordance with embodiments, the degassing line, at a second degassing line end opposite the first degassing line end, is fluidically connected to a liquid separator and/or to a fuel vapor filter comprising an activated charcoal filter.

In accordance with embodiments, the degassing line, at the second degassing line end, is firstly fluidically connected to the liquid separator and, via the liquid separator, to the fuel vapor filter comprising an activated charcoal filter. The gas passing out through the degassing line is therefore once again further treated via a further liquid separator, preferably separate from the filler pipe, before making its way to the activated charcoal filter. The liquid separator can be utilized also for a further function, in particular, for the separation in a separate refueling ventilation system.

In accordance with embodiments, a second ventilation line, in particular, a refueling ventilation line, fluidically connects the motor vehicle tank directly to the liquid separator.

In accordance with embodiments, a second degassing line fluidically connects the liquid separator to the fuel vapor filter.

DESCRIPTION

InFIG. 1, a ventilation device for ventilating a motor vehicle tank, in particular, a fuel tank, is represented, in accordance with embodiments.

The ventilation device comprises a filler pipe1and a ventilation line2to serve as an operating ventilation line. The ventilation line2, at a first ventilation line end, is to be fluidically connected to the motor vehicle tank (See,FIG. 1the lower end of the ventilation line2). The ventilation line2is to be fluidically connected at a second ventilation line end opposite the first end, downstream of a valve unit15, to the filler pipe1via a connecting nipple9, at a ventilation inlet3represented inFIG. 3.

The ventilation device further comprises a degassing line4to serve as a recirculating line. The degassing line4, at a first degassing line end, is to be fluidically connected to the filler pipe1via the same connecting nipple9, at a degassing outlet5represented inFIG. 3. The degassing line4, at a second degassing line end opposite the first end, is to be fluidically connected to a liquid separator10which is to serve as a so-called “liquid trap.” The ventilation inlet3and the degassing outlet5are configured on the common connecting nipple9on the filler pipe1.

The ventilation inlet3is positioned, in an installation position, at a top region of the filler pipe, so that vapor can fall though the ventilation inlet3into the filler pipe1. The degassing outlet5is also positioned, in the installation position, at the top region of the filler pipe1, or at least not close to the bottom of the filler pipe1, in order that only a gaseous component, but not liquid fuel, makes its way up to the degassing outlet5.

A second degassing line12fluidically connects the liquid separator10to a fuel vapor filter comprising an activated charcoal filter. In this context, inFIG. 1(at the top, on the left next to the connecting nipple9) is merely represented that end of the second degassing line12that is to be connected to the fuel vapor filter, not the fuel vapor filter itself.

A second ventilation line11, namely a refueling ventilation line, which has a greater diameter than the ventilation line2, fluidically connects the motor vehicle tank directly to the liquid separator10.

The connecting nipple9is more closely represented in the detail inFIG. 2. The section A-A which is marked inFIG. 2is represented inFIG. 3.

In the filler pipe1, a guide arc6is arranged and shaped such that a vapor passing through the ventilation inlet3into the filler pipe1, which vapor, the arrowed entering fuel-gas-mixture13, is guided between the inner wall of the filler pipe1and the guide arc6along the periphery of the filler pipe1, so that a gaseous component of the entering vapor, again marked by arrows as the gas14, escapes through the degassing outlet5and a liquid component of the entering vapor flows off through the filler pipe1(inFIG. 3in the direction towards the observer).

The guide arc6is configured, for instance, in the shape of a cylindrical segment or conical segment or funnel. On an outer wall of the guide arc6that faces the inner wall of the filler pipe1are configured, in some sections, a plurality of ribs7for separating off the liquid. The guide arc6is configured substantially as a profile of U-shaped or O-shaped cross-section.

In the filler pipe1, a flap member8is arranged at the degassing outlet5. The flap member8is mounted such that it is axially displaceable or moveable. When a fuel-pump nozzle is introduced into the filler pipe1, the flap member8is moved by the fuel-pump nozzle in a closing direction, and thus the degassing outlet5, during a refueling of the motor vehicle tank, is made smaller or closed.

The guide arc6is fastened at its upper ends, the ends of the branches of the U-shape, to the common connecting nipple9, or the guide arc6forms a portion of a flow guide of the ventilation device, for the positioning of a fuel-pump valve or fuel-pump nozzle and for the guidance of the fluid flow during the refueling of the motor vehicle tank. The guide arc6can also form the valve seat for the flap member8.

LIST OF REFERENCE SYMBOLS