FR3143666A1 - THERMAL AUTOMOTIVE VEHICLE WITH SCR TUBING (SELECTIVE CATALYTIC REDUCTION) WITH VORTEX DEGAZER - Google Patents

Abstract

The invention relates to a motor vehicle (100) comprising a thermal engine (1), an exhaust line (2) with a selective catalytic reduction catalyst (3) supplied with additive, from a fillable additive tank (4). by a filling pipe (10) comprising at its upper part a pipe head (11) provided with a sealing plug (12), this additive tank (4) also comprising a degassing pipe (13) going up to to the filling pipe (10) or the head of the pipe (11) where it opens, where this degassing pipe (13) passes through a separator (20) which is arranged to treat a discharge coming from the additive tank (4) , and separate, on the one hand the gas phase returned to the atmosphere, and on the other hand the liquid phase which is returned to the additive tank (4) by a return pipe (26). Figure 1

Description

THERMAL AUTOMOTIVE VEHICLE WITH SCR TUBING (SELECTIVE CATALYTIC REDUCTION) WITH VORTEX DEGAZER

The invention relates to a motor vehicle comprising at least one thermal engine associated with at least one exhaust line including a selective catalytic reduction catalyst, which selective catalytic reduction catalyst is supplied with additive, from an additive reservoir, by an injection pipe arranged to bring said additive by gravity to an injector located between said at least one engine and said selective catalytic reduction catalyst, and said additive reservoir being arranged to be filled with additive by a filling pipe comprising its upper part a tubing head provided with a sealing plug, said additive reservoir further comprising a degassing tubing going up to said filling tubing or said tubing head where it opens.

The invention relates to the field of CO _x , NO _x , and other gas exhaust circuits.

SCR (selective catalytic reduction) technology is one of the main systems for reducing harmful emissions. This technology converts nitrogen oxides NO _x into water and nitrogen, without oxides.

This process uses an additive, and in particular “AdBlue®”, which is a solution comprising 32.5% urea and 67.5% purified water; this additive is injected into an SCR catalyst. The heat from the exhaust breaks down the additive, notably “AdBlue®”, into ammonia NH ₃ , which creates the chemical reaction necessary to transform nitrogen oxides into nitrogen and water vapor. This chemical reaction transforms all or part of the NO _x into water H ₂ O and nitrogen N ₂ in the SCR catalyst.

The additive, notably “AdBlue®”, is stored in a tank specific to this liquid and which is added to the fuel tank. The additive, notably “AdBlue®”, is injected in liquid form, and interacts with the elements present in the SCR catalyst and with NO _x , which results in a reduction of approximately 90% in NO _x at the outlet of the exhaust system. All that remains is water H ₂ O, nitrogen N ₂ , and carbon dioxide CO ₂ . For optimal efficiency, the gas entering the SCR catalyst must be at a recommended temperature, and the exhaust pipe must be hot enough for this purpose.

This technology, designed for Diesel engines, has led to the creation of volume counters specific to the delivery of this additive. However, the recommended delivery flow rate is of the order of 10 liters per minute to 25 liters per minute for cars, while the flow rate at the volume meters is commonly of the order of 40 liters per minute for heavy goods vehicles. Adding additives to a car often gives rise to backflow phenomena at the filling port.

• niveau 1 : fuite sur la tête de la tubulure,
• niveau 2 : fuite sur l’environnement d’interface de la caisse,
• niveau 3 : refoulement jusqu’au pistolet d’injection,
• niveau 4 : refoulement sur la main de l’utilisateur ou du remplisseur,
• niveau 5 : refoulement sur tout le corps de l’utilisateur ou du remplisseur.

With a filling gun with a flow rate of 40 liters/minute, there are several levels of leaks or backflow through the degassing circuit on the additive, notably "AdBlue®", used in the SCR system , categorized into five levels of increasing severity:

• level 1: leak on the head of the tubing,
• level 2: leak on the checkout interface environment,
• level 3: delivery to the injection gun,
• level 4: discharge onto the hand of the user or filler,
• level 5: backflow over the entire body of the user or filler.

Document US6405767 B1 describes, to reduce turbulence in a fuel filling circuit, a vortex effect in a tank filling pipe, the vortex effect being created by vanes provided on the wall of this pipe.

Document FR3093475 B1 describes an assembly formed of a fluid intake pipe and a degassing pipe intended for a tank, the pipe comprising, over a portion of its length, a degassing box comprising a first compartment communicating with the pipe ; the degassing box comprises a second compartment surrounding the tubing in communication with the tubing, the first and second compartments being isolated from each other.

However, these mechanisms prove to be poorly suited to filling with a flow rate of 40 liters per minute.

The objective of the present invention is to remedy these drawbacks by treating the backflow at the inlet of the additive tank, by equipping the filling pipe with a device separating the gas phase and the liquid phase from the backflow, capable of authorize the rise of the gas phase towards the filling port, and to prohibit the rise of the liquid phase towards the filling port, and forcing it to return to the additive tank.

The invention will make it possible to solve the problem of backflow (rising of the flow towards the degassing pipe and the usual degassing box), in particular droplets or air bubbles which appear when filling the additive tank.

The invention consists of adding a degasser system comprising two parts, an upper part which acts as a closing cover and which comprises a circuit for evacuating the gases or air which is in the additive tank, and a lower part which contains elements which allow the circulation of the liquid discharged from the tank during filling.

The invention makes it possible to ensure the recirculation of liquid rises at the level of the degasser circuit, in particular by vortex elements set up to have swirls of the additive liquid, in particular "AdBlue®", which vortex elements go create air depressions. A centripetal force from the vortices drives the gases toward the additive fill port. These vortex elements make it possible to keep the circulation moving and, under the effect of the weight of the liquid and always under the effect of the centripetal force created by the vorticity of the vortex, to trap the liquid in the center, and, consequently , to direct the discharged additive towards the passage of a return pipe to return to the tank. And the choice of a larger diameter in the additive return pipe makes it possible to have and maintain a monodirectional flow under the force of the liquid return flow to the vortices.

To achieve this objective, the invention proposes the installation of a degassing box integrated into the intake pipe and comprising a vortex degasser system in the tubing towards the SCR tank.

Thus the invention relates to a motor vehicle comprising at least one thermal engine associated with at least one exhaust line including a selective catalytic reduction catalyst, which selective catalytic reduction catalyst is supplied with additive, from an additive reservoir, by an injection pipe arranged to bring said additive by gravity to an injector located between said at least one engine and said selective catalytic reduction catalyst, and said additive reservoir being arranged to be filled with additive by a filling pipe comprising its upper part a tubing head provided with a sealing plug, said additive reservoir further comprising an outlet to a degassing tubing going up to said filling tubing or said tubing head where it opens.

According to the invention, said degassing pipe passes through a separator which is arranged to treat a discharge coming from said additive reservoir, and separate therefrom, on the one hand the gas phase returned to the atmosphere or to said pipe head, and on the other hand the liquid phase which is returned to said additive tank by a return pipe.

This arrangement eliminates the backflow of liquid towards the filling port, and allows supply to high flow terminals without any adverse consequences for the user.

Advantageously, according to a characteristic of the invention, said return pipe is distinct from said degassing pipe. Thus the return flow is carried out in a single direction of fluid circulation.

According to one characteristic of the invention, said separator is arranged to conduct said gas phase leaving said separator via at least one gas pipe which joins an upper part of said degassing pipe, which upper part is distinct from a lower part of said degassing pipe where said discharge takes place, and said separator is arranged to lead said liquid phase towards said additive tank via a return pipe.

This arrangement completely distinguishes the liquid circuits specific to filling, and those dedicated to the treatment of discharge.

According to another characteristic of the invention, said separator comprises, together forming a closed chamber, an upper housing comprising a gas evacuation circuit via at least one said gas pipe, and a lower housing comprising a supplied inlet channel by said lower part of said degassing pipe, said lower housing containing elements arranged to allow the circulation of the discharge fluid in said separator, to separate its gas phase and its liquid phase, said lower housing also comprising an outlet channel additive joining said return pipe.

The separator according to the invention thus comprises two simple elements, each dedicated to the conveying of a phase: gas phase for the upper element, liquid phase for the lower element in which the separation treatment of the two phases takes place.

According to an advantageous characteristic, said additive outlet channel has a section greater than that of said inlet channel. This makes it possible to have and maintain a one-way flow, under the force of the liquid return flow imposed by the separator.

According to another advantageous characteristic, said elements which said lower housing comprises are vortex elements arranged to create at least one swirl of said additive in said chamber.

Thus the separator does not require any motorization, and is very economical to manufacture.

According to a more particular characteristic, said separator comprises at least one pair of said vortex elements juxtaposed and arranged to create vortices in opposite directions.

The flow rate is thus perfectly controlled, for each of the two phases.

According to a particular characteristic, in an alternative said return pipe joins said filling pipe in the vicinity of said additive tank. The invention is thus easily adaptable to an existing circuit, and avoids modifying the tank.

According to another particular characteristic, in another alternative said return pipe directly joins said additive tank. The invention is thus easily adaptable to an existing circuit, and avoids modification of the filling pipe.

According to a particular characteristic, said upper part of said degassing pipe directly joins said pipe head. The invention is thus easily adaptable to an existing circuit thus configured.

• illustre schématiquement et en perspective un véhicule automobile selon l’invention, comportant un moteur thermique, avec une ligne d’échappement incluant un catalyseur de réduction catalytique sélective, alimenté en additif, depuis un réservoir d’additif, par une tubulure d’injection via un doseur et un injecteur; ce réservoir d’additif est rempli en additif par une tubulure de remplissage comportant à sa partie supérieure une tête de tubulure munie d’un bouchon obturateur, et comporte une tubulure de dégazage qui traverse un séparateur de phases propre à l’invention. Les flèches droites en trait mixte figurent le flux d’additif depuis un pistolet d’injection externe, non représenté, introduit dans la tête de tubulure, et jusqu’au réservoir. Les flèches droites en trait plein figurent un flux mixte de refoulement (gaz et liquide) depuis le réservoir au travers de la tubulure de dégazage. Les flèches droites en trait double figurent un flux de retour de la seule phase liquide vers le réservoir. Les flèches droites en trait interrompu figurent un flux de gaz issu du séparateur et remontant vers la tête de tubulure ;
• illustre schématiquement et en perspective, l’ensemble des tubulures situées entre la tête de tubulure et le réservoir, et leurs connections avec le séparateur de l’invention. Les flèches rotatives en trait double au niveau du séparateur montrent le flux imposé par des éléments agencés pour permettre la circulation du fluide de refoulement dans le séparateur, pour séparer sa phase gazeuse et sa phase liquide ;

• illustre schématiquement et en vue de dessus, le séparateur, dans une version en deux parties non limitative, et dont on voit essentiellement la partie supérieure, ainsi que le canal d’entrée du fluide de refoulement, et le canal de sortie d’additif en retour, lequel a une section supérieure à celle du canal d’entrée, ces deux canaux étant raccordés à la partie inférieure du séparateur. En trait interrompu on voit une paire de vortex logés dans la partie inférieure du séparateur, à l’axe de chacun desquels est situé une conduite d’évacuation de gaz de la partie supérieure ;
• illustre schématiquement et en coupe par le plan de coupe AA de , le séparateur vu en , avec, de bas en haut la partie inférieure et un des vortex, et la partie supérieure avec une des conduites de gaz, connectée à une partie supérieure de la tubulure de dégazage ;
• illustre schématiquement et en élévation le séparateur vu en , avec, de bas en haut la partie inférieure avec le canal d’entrée du fluide de refoulement, et le canal de sortie d’additif en retour, et la partie supérieure avec les deux conduites de gaz, connectées à la partie supérieure de la tubulure de dégazage ;
• illustre schématiquement et en vue de dessus la partie inférieure du séparateur vu en , avec sa paire de vortex, le canal d’entrée du fluide de refoulement, et le canal de sortie d’additif en retour ;
• illustre schématiquement et en perspective la même partie inférieure du séparateur vu en ;
• illustre schématiquement et en perspective sous un autre angle la même partie inférieure du séparateur vu en .

The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which:

• illustrates schematically and in perspective a motor vehicle according to the invention, comprising a thermal engine, with an exhaust line including a selective catalytic reduction catalyst, supplied with additive, from an additive tank, by an injection pipe via a doser and an injector; this additive reservoir is filled with additive by a filling pipe comprising in its upper part a pipe head provided with a sealing plug, and comprises a degassing pipe which passes through a phase separator specific to the invention. The straight arrows in dashed lines represent the flow of additive from an external injection gun, not shown, introduced into the tubing head, and to the reservoir. The solid straight arrows represent a mixed discharge flow (gas and liquid) from the tank through the degassing pipe. The straight double-line arrows represent a return flow of the liquid phase alone towards the reservoir. The straight arrows in broken lines represent a flow of gas coming from the separator and rising towards the head of the tubing;
• illustrates schematically and in perspective, all of the tubing located between the tubing head and the reservoir, and their connections with the separator of the invention. The rotating arrows in double lines at the level of the separator show the flow imposed by elements arranged to allow the circulation of the discharge fluid in the separator, to separate its gas phase and its liquid phase;

• illustrates schematically and in top view, the separator, in a version in two non-limiting parts, and of which we essentially see the upper part, as well as the inlet channel of the discharge fluid, and the additive outlet channel in return, which has a section greater than that of the input channel, these two channels being connected to the lower part of the separator. In broken lines we see a pair of vortices housed in the lower part of the separator, at the axis of each of which is located a gas evacuation pipe from the upper part;
• illustrated schematically and in section by the section plane AA of , the separator seen in , with, from bottom to top, the lower part and one of the vortices, and the upper part with one of the gas pipes, connected to an upper part of the degassing pipe;
• illustrates schematically and in elevation the separator seen in , with, from bottom to top the lower part with the delivery fluid inlet channel, and the additive outlet channel in return, and the upper part with the two gas pipes, connected to the upper part of the degassing tubing;
• illustrates schematically and in top view the lower part of the separator seen in , with its pair of vortices, the delivery fluid inlet channel, and the additive outlet channel in return;
• illustrates schematically and in perspective the same lower part of the separator seen in ;
• illustrates schematically and in perspective from another angle the same lower part of the separator seen in .

The interacting elements in the invention are an external gun for injecting the additive, in particular and not limited to “AdBlue®”, and the elements integrated into the motor vehicle, in particular the SCR tubing and its tank. The invention must make it possible, when filling the SCR tank, and in the case of liquid discharge, to separate the gaseous and liquid phases of such discharge, and to return the liquid phase to the SCR tank, and to guide the gas phase via the degassing pipe to rise to the gun level.

The invention relates to a motor vehicle 100 comprising at least one thermal engine 1, which is associated with at least one exhaust line 2 including a selective catalytic reduction catalyst 3 (abbreviation SCR). This selective catalytic reduction catalyst 3 is supplied with additive, from an additive reservoir 4, by an injection pipe 5 which is arranged to bring the additive by gravity, in particular through a doser 5 to a point d injection or to an injector 6, which is located between this at least one engine 1 and the selective catalytic reduction catalyst 3.

The additive reservoir 4 is arranged to be filled with additive by a filling tube 10 comprising at its upper part a tube head 11 provided with a sealing plug 12. This tube head is arranged to receive an injection gun external. The additive tank 4 also has an outlet to a degassing pipe 13, which goes up to the filling pipe 10, or to the pipe head 11, where it opens.

According to the invention, the degassing pipe 13 passes through a separator 20 which is arranged to treat a discharge coming from the additive tank 4, and to separate therefrom, on the one hand the gas phase returned to the atmosphere or to the head of the additive. tubing 11, and on the other hand the liquid phase which is returned to the additive tank 4 by a return pipe 26.

More particularly, the return pipe 26 is distinct from the degassing pipe 13.

More particularly, the separator 20 is arranged to conduct the gas phase leaving the separator 20 via at least one gas pipe 23, 24, which joins an upper part 25 of the degassing pipe 13. This upper part 25 is distinct from a lower part 27 of the degassing pipe 13 where the discharge takes place. And the separator 20 is arranged to lead the liquid phase to the additive tank 4 via a return pipe 26.

More particularly, in a non-limiting version of the invention and illustrated by the figures, the separator 20 comprises, together forming a closed chamber, an upper housing 21 comprising a gas evacuation circuit via at least one gas pipe 23, 24, and a lower housing 22 comprising an inlet channel 28 supplied by the lower part 27 of the degassing pipe 13. This lower housing 22 contains elements 30, which are arranged to allow the circulation of the discharge fluid in the separator 20, to separate its gas phase and its liquid phase. The lower housing 22 also includes an additive outlet channel 29 joining the return pipe 26.

More particularly, the additive outlet channel 29 has a section greater than that of the inlet channel 28.

More particularly, the elements 30 that the lower housing 22 comprises are vortex elements, which are arranged to create at least one swirl of the additive in the chamber.

Even more particularly, the separator 20 comprises at least one pair of such vortex elements, juxtaposed and arranged to create vortices in opposite directions.

Alternatively, the return pipe 26 joins the filling pipe 10 in the vicinity of the additive tank 4.

In another alternative, the return line 26 joins directly the additive tank 4.

In a variant, the upper part 25 of the degassing pipe 13 joins directly the head of the pipe 11.

The invention is thus easily adaptable to an existing set of SCR tubing, and only requires minor modifications. The separator is inexpensive and does not require any motorization or special services.

In short, the invention makes it possible to ensure the recirculation of liquid rises at the level of the degasser circuit by the vortex elements put in place to swirl the additive liquid, in particular “AdBlue®”; these vortices which will create air depressions, that is to say a centripetal force due to the vortex which drives the gases towards the SCR gun on the one hand, and, on the other hand which will make it possible to keep the circulation moving and, under the effect of the weight of the liquid and always under the effect of the centripetal force created by the vorticity of the vortex, to trap the liquid in the center and consequently, to direct the discharged liquid towards the passage of the pipeline. additive outlet, also known as “overflow back” to return to the tank. And the presence of a larger diameter in the additive return pipe makes it possible to have and maintain a one-way flow, under the force of the liquid return flow to the vortices.

The invention has the advantage of keeping the main filling pipe intact, the flow rate of which is calibrated at a minimum of 10 liters/minute, and of being able to use it on stations whose filling flow rate is higher, in particular recommended at 40 liters. /minute.

In summary, the invention ensures recirculation of the additive flow, in particular “AdBlue®”, between the secondary pipe (degassing pipes) and the tank to eliminate backflows.

The invention further ensures the improvement of the method of filling the SCR tank, which improves any marketed SCR system. And in particular the invention ensures operational safety, with the elimination of negative effects due to liquids flowing back towards the user, which improves customer satisfaction.

Claims (10)

Motor vehicle (100) comprising at least one thermal engine (1) associated with at least one exhaust line (2) including a selective catalytic reduction catalyst (3), which selective catalytic reduction catalyst (3) is supplied with additive , from an additive reservoir (4), via an injection pipe (5) arranged to bring said additive by gravity to an injector (6) located between said at least one engine (1) and said selective catalytic reduction catalyst (3), and said additive reservoir (4) being arranged to be filled with additive by a filling tube (10) comprising at its upper part a tube head (11) provided with a sealing plug (12), said additive reservoir (4) further comprising an outlet towards a degassing pipe (13) going up to said filling pipe (10) or said pipe head (11) where it opens, characterized in that said filling pipe degassing (13) passes through a separator (20) which is arranged to treat a discharge coming from said additive reservoir (4), and separate therefrom, on the one hand the gas phase returned to the atmosphere or to said head of tubing ( 11), and on the other hand the liquid phase which is returned to said additive tank (4) by a return pipe (26). Motor vehicle (100) according to claim 1 characterized in that said return pipe (26) is distinct from said degassing pipe (13). Motor vehicle (100) according to claim 1 or 2 characterized in that said separator (20) is arranged to conduct said gas phase leaving said separator (20) via at least one gas pipe (23, 24) which joins an upper part (25) of said degassing pipe (13), which upper part (25) is distinct from a lower part (27) of said degassing pipe (13) where said discharge takes place, and in that said separator (20) ) is arranged to lead said liquid phase to said additive reservoir (4) via a return pipe (26). Motor vehicle (100) according to claim 3 characterized in that said separator (20) comprises, together forming a closed chamber, an upper housing (21) comprising a gas evacuation circuit via at least one said gas pipe (23). , 24), and a lower housing (22) comprising an inlet channel (28) supplied by said lower part (27) of said degassing tube (13), said lower housing (22) containing elements (30) arranged to allow the circulation of the discharge fluid in said separator (20), to separate its gas phase and its liquid phase, said lower housing (22) further comprising an additive outlet channel (29) joining said return pipe (26 ). Motor vehicle (100) according to claim 4 characterized in that said additive outlet channel (29) has a section greater than that of said inlet channel (28). Motor vehicle (100) according to claim 4 or 5 characterized in that said elements (30) which said lower housing (22) comprises are vortex elements arranged to create at least one swirl of said additive in said chamber. Motor vehicle (100) according to claim 6 characterized in that said separator (20) comprises at least one pair of said vortex elements juxtaposed and arranged to create vortices in opposite directions. Motor vehicle (100) according to one of claims 1 to 7 characterized in that said return pipe (26) joins said filling pipe (10) in the vicinity of said additive tank (4). Motor vehicle (100) according to one of claims 1 to 7 characterized in that said return pipe (26) directly joins said additive tank (4). Motor vehicle (100) according to one of claims 1 to 9 characterized in that said upper part (25) of said degassing pipe (13) directly joins said pipe head (11).