FR3124765A1 - MOTOR VEHICLE FUEL TANK SYSTEM WITH DEGASING PIPE - Google Patents

Abstract

Motor vehicle fuel tank system comprising a tank, a filler pipe (4), and a degassing pipe successively comprising a degassing tube (16) arranged in parallel with the filler pipe (4), a bent tube ( 20) linked by an attachment to the degassing tube (16), having a first straight part (34) entering this degassing tube (16), connected by an elbow to a second straight part (32), and comprising a flexible pipe connecting this second part (32) to the reservoir, the attachment of the bent tube (20) to the degassing tube (16) comprising a connection which can pivot along the axis of the first straight part (34). Figure 2

Description

MOTOR VEHICLE FUEL TANK SYSTEM WITH DEGASING PIPE

The present invention relates to a motor vehicle fuel tank system comprising a degassing line, as well as a motor vehicle equipped with such a tank system.

A known type of motor vehicle tank, presented in particular by the document FR-A1-2630686, comprises a filling pipe having an upper inlet closed by a cap covered by a hatch, and a lower end opening into the lower part of the fuel tank. fuel.

The tank system comprises a device for venting the tank to prevent internal overpressure, comprising two conduits arriving on two opposite sides of an upper volume of the tank, which lead to a raised valve allowing the gases to be evacuated in case of overpressure in this tank. A tilting magnet system controlled by the opening of the filler cap flap, allows this valve to be closed when filling the tank.

The tank system further comprises a degassing pipe allowing a discharge of the gases contained in the tank during its filling, having a lower end connected above the tank to receive the gases formed by a mixture of air and fuel vapors , and an upper end opening into the filling tube close to its opening, next to a deflector preventing liquid from passing into this gas outlet.

In this way, the tank can be filled with a rapid flow forming a flow covering the complete section of the filling tube while the gases from the tank rise in parallel through the degassing pipe, which avoids a contrary gas flow which would disturb the flow. liquid flow. Once the tank has been filled and its cap closed, the degassing pipe is no longer used.

The degassing pipe comprises starting from the tank, generally placed under the floor of the boot of the vehicle, a substantially horizontal flexible pipe making it possible to approach the side of the vehicle where the filler cap is located, then a bent tube directed upwards connecting to a degassing tube fixed parallel to the filling pipe, to reach the upper connection with this pipe.

In particular, it is known to produce the degassing tube by a rigid plastic molding linked to the filling pipe, forming a column having at its base a vertical cylindrical part comprising a lower opening.

The rigid bent tube formed by molding a plastic material, has a straight horizontal part connected to the flexible pipe, and a straight vertical part which rises in the column of the degassing tube, comprising at its base a collar fixed to the opening bottom of the cylindrical part of this tube. In this way, a gas outlet is obtained at the end of the vertical part opening into the column, which allows droplets of fuel streaming down the walls of this column, to descend around this vertical part in order to be evacuated by a side passage to the filling tube.

However, in the event of an accident, in particular in the event of a rear impact on the vehicle, interference can be obtained from deformed elements of this vehicle coming into contact with the degassing pipe by applying stresses. In particular, the rigid bent tube placed at the level of the floor of the vehicle can be subjected to strong stress and become dislodged from the degassing tube or break, forming an opening in the fuel tank resulting in serious risks. The standardized rear impact tests on the vehicle for its approval prohibit this type of incident.

The object of the present invention is in particular to avoid these problems of the prior art.

It proposes for this purpose a motor vehicle fuel tank system comprising a tank, a filling pipe, and a degassing pipe successively comprising a degassing tube arranged in parallel with the filling pipe, a bent tube connected by a fixing to the degassing tube, having a first straight part entering this degassing tube, connected by an elbow to a second straight part, and comprising a flexible pipe connecting this second part to the tank, this system being remarkable in that the fixing of the tube bent on the degassing tube comprises a connection which can pivot along the axis of the first straight part.

An advantage of this fuel tank system and that in the event of impact or pressure on the degassing pipe, in particular on the elbow tube formed of rigid elements, the pivoting connection allows its second lower part to pivot freely according to all orientations, in particular in the horizontal plane, under the effect of deformed elements which would press on this pipe, without placing any stress on its attachment to the degassing tube.

In a simple way, with a bent tube having overall the same size, which avoids modifying parts in the surroundings, and reduces the costs of adaptations, the constraints which could be applied to this element formed by rigid elements assembled together are limited. , in order to avoid dislocations or ruptures which makes it possible to preserve the tightness of the tank and to ensure safety.

The reservoir system according to the invention may additionally comprise one or more of the following characteristics, which may be combined with one another.

Advantageously, the tank system comprises an annular fixing base surrounding the first part of the bent tube to form the pivot connection.

In this case, advantageously the fixing base comprises an outer contour which is fixed on a transverse end face of the degassing tube.

Advantageously, the fixing base comprises a cylindrical bore which fits on a cylindrical guide surface of the first part of the bent tube.

Advantageously, the tank system comprises an O-ring seal placed between the fixing base and the first part of the bent tube.

Advantageously, the tank system comprises a clipping system axially maintaining the first part of the bent tube in the fixing base.

In this case, the fixing base may comprise an inner annular boss having axial slots giving it elasticity, which fits into an annular groove of the first part of the bent tube to form the clipping.

Advantageously, the bent tube and the fixing base are each formed by molding plastic material.

The invention also relates to a method for assembling a tank system comprising any one of the preceding characteristics, which introduces the first part of the bent tube axially into a bore connected to the degassing tube, then exerts an axial pressure to achieve an axial retaining clipping of the bent tube in this hole.

The invention further relates to a motor vehicle comprising a tank system comprising any one of the preceding characteristics.

The invention will be better understood and other characteristics and advantages will appear more clearly on reading the description below given by way of example, with reference to the appended drawings in which:

presents a reservoir system according to the prior art;

is an axial sectional view of a bent tube of a tank system according to the invention, fixed to the base of the degassing tube;

presents this bent tube in an exploded view; And

has different orientations which can be taken by the lower horizontal part of the bent tube during an impact on the rear of the vehicle.

Throughout the document, the expressions upper, lower, above and below relate to a vehicle resting on horizontal ground. The forward direction indicated by the forward arrow is facing the front of the vehicle in its direction of travel.

There has a fuel tank 2 comprising a filler pipe 4 comprising a substantially vertical part receiving at its upper end a closure cap 8, and a substantially horizontal part 6 which opens onto the tank. In this way the tank cap 8 can be arranged on a rear wing of the vehicle, the vertical part then descending in this wing to reach the height of the tank 2, then after a substantially 90° bend the horizontal part 6 circulates under the floor of the boot to reach this tank located further forward.

An electric pump 10 fixed on the top of the tank 2, takes the fuel to send it through a pipe 12 to the powertrain arranged at the front of the vehicle.

An upper volume 14 arranged behind the tank 2 receives the gases contained in this tank when it is filled, to evacuate them via a degassing pipe successively comprising a flexible pipe 22 which follows the horizontal part of the filling pipe 6, a bent tube rigid 20 forming an angle of 90°, then a degassing tube 16 which follows the vertical part of the filling pipe 4, to emerge at the top of this pipe.

The bent tube 20 comprises at the base of its vertical part a collar welded into a lower cylindrical shape 18 of the degassing tube 16, then the vertical part which rises in the degassing tube to prevent fuel from descending into this bent tube.

In the event of an impact on the rear of the vehicle, elements surrounding the degassing pipe can move, for example supports for the exhaust pipe arranged nearby, and press against the horizontal part of the bent tube 20. In this case the rigid bent tube 20 fixed to the rigid degassing tube also 16, which is itself fixed to the filling pipe 4, cannot bend, risks breaking by creating an opening in the fuel tank which can lead to leaks.

There has the lower cylindrical shape 18 of the degassing tube 16 receiving on its transverse lower face an annular fixing base 50 which is welded underneath. The straight and substantially vertical upper tubular part 34 of the bent tube 20 enters a hole in the fixing base 50 with a pivot connection along the axis of this vertical part, allowing complete pivoting over 360° of its lower right tubular part. and substantially horizontal 32.

Figures 2 and 3 show the second lower tubular part 32 equipped at its end with annular grooves allowing fitting and fixing of the flexible pipe 22 connected to the reservoir 2, then the 90° elbow, and then the first upper tubular part 34 which allows mounting in the degassing tube 16.

The upper tubular part 34 comprises successively, starting from the bottom, a sleeve 36 having an upper transverse bearing face 38 receiving the support of an O-ring 40, a cylindrical guide surface 42, an annular groove 44, a conical shape tightening 46, and finally a tubular part sui is smooth.

The fixing base 50 comprises in the lower part an outer flange 52 having an upper transverse bearing surface which is welded to the cylindrical shape 18 of the degassing tube 16.

The drilling of the fixing base 50 comprises successively starting from the bottom a cylindrical bore of large diameter ending in a transverse bearing face receiving the support of the O-ring 40, then a cylindrical bore of small diameter fitting on the cylindrical guide surface 42 of the bent tube 20 making it possible to ensure a play-free pivot connection around the axis of the upper tubular part 34.

The drilling of the fixing base 50 finally comprises an internal annular boss 54 cut by axial slots giving radial elasticity to this boss, which when the upper tubular part 34 is raised in this drilling opens on reaching the conical shape 46, then falls into the annular groove 44 by performing a clipping preventing the disengagement of the bent tube 20.

The bent tube 20 and the fixing base 50 are each formed in one piece by molding in plastic material, making it possible to obtain complex shapes including the holes in an economical manner.

An assembly method is obtained comprising a simple introduction of the upper tubular part 34 of the elbow tube 20 into the bore of the fixing base 50 fixed under the degassing tube 16, putting in place the pivot connection ensured by the cylindrical surfaces guide 42 fitting one over the other, then with a final axial pressure an automatic clipping of the annular boss 54 of the base which locks the axial positioning of this connection.

There present during an accident on the rear of the vehicle, with elements of this vehicle applying pressures which tend to move the degassing pipe, or the filling pipe 4 supporting this first pipe, a free pivoting of the bent tube 20 around of the substantially vertical axis of its upper tubular part 34, allowing complete and free angular pivoting in the horizontal plane of its lower tubular part 32. This provides protection for the bent tube 20 and its attachment to the degassing tube 16 , which limits the stresses applied to it by avoiding the risk of dislocation or breakage.

Claims (10)

Motor vehicle fuel tank system comprising a tank (2), a filler pipe (4), and a degassing pipe successively comprising a degassing tube (16) arranged in parallel with the filler pipe (4), a bent tube (20) connected by an attachment to the degassing tube (16), having a first straight part (34) entering this degassing tube (16), connected by a bend to a second straight part (32), and comprising a flexible pipe (6) connecting this second part (32) to the reservoir (2), characterized in that the attachment of the elbow tube (20) to the degassing tube (16) comprises a connection which can pivot along the axis of the first right part (34). Tank system according to Claim 1, characterized in that it comprises an annular fixing base (50) surrounding the first part (34) of the elbow tube (20) to form the pivot connection. Tank system according to Claim 2, characterized in that the fixing base (50) has an outer contour which is fixed to a transverse end face of the degassing tube (16). Tank system according to Claim 2 or 3, characterized in that the fixing base (50) comprises a cylindrical bore which fits on a cylindrical guide surface (42) of the first part (34) of the bent tube ( 20). Reservoir system according to any one of Claims 2 to 4, characterized in that it comprises an O-ring seal (40) placed between the fixing base (50) and the first part (34) of the bent tube (20). Tank system according to any one of Claims 2 to 5, characterized in that it comprises a clipping system axially holding the first part (34) of the bent tube (20) in the fixing base (50). Tank system according to Claim 6, characterized in that the fixing base (50) comprises an internal annular boss (54) having axial slots giving it elasticity, which fits into an annular groove (44) of the first part (34) of the bent tube (20) to form the clipping. Tank system according to any one of Claims 2 to 7, characterized in that the elbow tube (20) and the fixing base (50) are each formed by molding plastic material. Method of assembling a tank system according to any one of the preceding claims, characterized in that it introduces the first part (34) of the bent tube (20) axially into a bore connected to the degassing tube (16) , then it exerts an axial pressure to achieve an axial retaining clipping of the bent tube (20) in this hole. Motor vehicle comprising a tank system, characterized in that this tank system is according to any one of Claims 1 to 8.