IT201800011135A1 - Tank equipped with filler neck and method for manufacturing said tank - Google Patents

Description

Tank equipped with filler neck and method for manufacturing said tank

DESCRIPTION

Technical sector

The present invention relates to a tank equipped with a filler neck and a method for manufacturing said tank. The tank according to the invention is capable of containing a fluid in a liquid state, intended for a selective catalytic reduction (SRC) system of an exhaust system of an internal combustion engine. More specifically, the tank according to the invention can be installed on a vehicle equipped with an internal combustion engine, equipped with an exhaust system that incorporates an SCR selective catalytic reduction system.

Note Art

SCR ("Selective Catalytic Reaction") technology is based on a reduction of ammonia NH3 to nitrogen N2, resulting in the transfer of hydrogen H atoms to nitrogen oxides NOx, to form H20 water molecules and N2 nitrogen molecules. This reaction is stoichiometric, that is, if a sufficient quantity of ammonia is fed and proportionate to the quantity of NOx produced by the I.C. in a predetermined volume, or reaction chamber, all NOx will be transformed into water and nitrogen. The SCR technology therefore allows to reduce the NOx that are emitted into the atmosphere with the exhaust gases of an internal combustion engine.

The SCR system is generally fed with a 32.5% by weight urea solution and 67.5% demineralized water. This solution is commercially known as by the name AdBlue®. The supply of AdBlue® to the reduction system incorporated in the exhaust system of an endothermic engine takes place via a suction pump connected to an injection system. Upstream of the pump there is a supply circuit connected to a tank in which the AdBlue® liquid is stored.

As is known, the AdBlue® liquid contained in the tank solidifies when the temperature drops below -11.5 ° C.

Currently, to prevent the urea solution from freezing, the tank is equipped with a unit known as a "sender unit", capable of heating the liquid contained in the tank by means of a heat exchanger and allowing its withdrawal through a duct or float. The heat exchanger comprises a metal duct, in which the coolant of the internal combustion engine circulates, the exhaust gases of which are treated with the AdBlue® solution contained in the tank. Thanks to the heat exchanger, the temperature of the AdBlue® liquid contained in the tank is brought and maintained at a temperature above -11.5 degrees centigrade.

The "sender unit" also includes delivery and return pipes for the liquid contained in the tank, respectively for sending the liquid from the tank to the suction pump and for returning the excess quantity to the tank.

Newer “sender” units come with some add-ons in addition to those mentioned. In particular, "sender" units are known equipped with sensors for measuring parameters of the liquid contained in the tank, such as level, temperature and quality, the latter parameter being generally established by measuring the concentration of urea in the solution.

The known type "sender" units are also equipped with mesh filters for a coarse filtration of the solution contained in the tank, before it is sucked from the tank to be sent to the metering pump.

Finally, the "sender" units are also equipped with an electronic board for the acquisition of signals from the sensors and electrical connectors, for connecting the unit to an electrical circuit associated with an electronic control unit for controlling the operation of the control system. SCR reduction.

The current "sender" units integrate, as shown above, in a single device, the function of heating and drawing the liquid contained in the tank. According to known technique, the "sender" unit includes an internal portion of the tank, an external portion and a flange, placed between the internal and external portion for fixing the unit to the tank wall at a suitable hole. The unit is therefore inserted into the tank through an opening in the tank wall and fixed to the tank by screws that engage in the flange. This mode of operation determines a series of drawbacks and limitations. For example, the shape and development of the part of the "sender" unit housed in the tank cannot be chosen at will, for example to increase the de-icing capacity and speed, but must be compatible with the inlet hole to allow assembly. Furthermore, the currently known "sender" units are designed to be installed generally at the top of the tank, typically in correspondence with the upper face thereof. This limitation determines the need to create “sender” units equipped with a suction pipe of adequate length, to suck up the liquid as the tank empties. Said suction duct is subject to vibrations while the vehicle is running and is therefore susceptible to breakage.

Also due to the aforementioned circumstance, the addition of additional functions and components, such as sensors, in a "sender" unit of the aforementioned type is currently difficult.

US 2011/0271754 and EP3177814 (A1) describe an example of a known type of "sender" unit.

The current tanks foreseen for the containment of a urea solution are also equipped with a filler neck equipped with a closing cap. The nozzle allows the tank to be filled through the trunk of a container containing the urea solution or through the trunk of a dispensing gun. The urea solution is highly corrosive and it is necessary that the union has an adequate passage to said proboscis, which avoids the leakage of substance during refueling.

To prevent impurities from entering the tank during filling operations, the filler is also equipped with a filter. The filter includes a cylindrical tube open on the bottom and side and equipped with a net. The tube has a section suitable for receiving the standard proboscis of a filling gun or a container containing the urea solution and is introduced through an annular flange, fixed to the tank in correspondence with a hole provided for this purpose. The pipe is fixed to the flange by means of a coupling system that allows the filter to be removed for cleaning. In known unions currently used, the filtering surface is therefore determined by the diameter of the cylindrical tube. Currently, the filter surface of the filler neck of a urea tank is approximately 4070 mm <2>.

This circumstance determines a reduced flow of urea solution through the union, with consequent long filling times. Furthermore, the described configuration of the known art, determines a reduced filtration capacity, with the consequent risk of introducing impurities into the tank during the operations of refueling the urea solution.

A first purpose of the invention is to solve the drawbacks and limitations of the known art, by providing a tank equipped with a filler neck that allows for faster refueling.

Another purpose of the invention is to provide a tank equipped with a filler neck with improved filtering capacity.

Not least object of the invention is to provide a tank for urea solution, capable of being installed on board a vehicle equipped with an internal combustion engine and an SCR system for the reduction of NOx in the exhaust gases, which can be manufactured industrially. at low cost and in large series.

The aforementioned purposes, and others, are achieved with the tank according to the invention, as claimed in the attached claims.

Description of the Invention

The tank according to the invention is equipped with a filler neck and includes a plastic wall defining a tank chamber inside it. The tank is also preferably provided with a group for heating and drawing the fluid contained in the tank.

Advantageously, according to the invention, said union comprises a body in plastic material in which an external hollow portion and an internal hollow portion are defined. Furthermore, the external hollow portion includes a cylindrical portion with a larger section than that of the internal portion and equipped with at least one side opening that houses a filtering net.

Still according to the invention, the external portion of the filler neck comprises preferably opposite bases both open and has a substantially cylindrical development with a circular cross-section. Said outer portion of the filler neck also comprises a laterally closed portion and a laterally open portion in succession axially aligned and said laterally open portion and the open base of said laterally open portion are also provided with a filtering mesh.

Preferably, the laterally open portion is defined by a series of axial extensions which extend along as many generatrices starting from the laterally closed portion and preferably terminate at an annular portion that surrounds said open base of the outer portion of the union.

The union further comprises an internal hollow portion comprising a preferably cylindrical body with a circular cross-section preferably housed in a removable manner in the external hollow portion. Said inner portion, when housed in the outer portion of the union, extends for the entire length of the closed portion starting from the open base and for a portion of the open portion preferably corresponding to at least about 1⁄4 of the length of said open portion.

The internal portion also preferably comprises an annular ring provided with fins extending axially outside said annular ring and the internal portion can be engaged in or disengaged from the external portion by manually rotating the internal portion by means of said fins, thanks to a threaded coupling or bayonet type between said inner and outer portions of the union according to the invention.

According to the invention, the tank is therefore equipped with a filler neck to introduce the liquid into the tank, preferably equipped with a mesh filter specially sized to be able to increase the surface of the liquid passage during the filling of the tank. In this way it is advantageously possible to make the filter of the filler neck with porosity lower than the current 100 microns. According to this particular embodiment of the invention, the filler neck filter can be made with porosities ranging from 20 to 100 microns.

Advantageously, according to this particular embodiment of the invention, the filtering surface of the union will be at least about 9550 mm2, to allow an adequate filling speed, despite the reduction of the porosity of the filtering surface.

Advantageously, according to the invention, the union therefore comprises a filtering surface, preferably of at least 9550 mm <2>, i.e. considerably wider than that of the unions made in accordance with the current state of the art.

Still according to the invention, the tank is provided with a seat capable of hosting a filler for refueling the tank. The seat is preferably obtained in a cylindrical extension that extends outside the tank in a direction substantially perpendicular to the upper face of the tank body. This seat also houses a preferably circular opening, which houses the union.

In accordance with a preferred embodiment of the invention, the tank equipped with a filler neck comprises a wall in plastic material defining inside it a chamber of the tank and a group for heating and drawing the fluid contained in the tank. In accordance with the invention, the method of making a tank provides for a phase in which a cylindrical extension is obtained in the tank wall during a molding phase of the tank to accommodate the filler neck.

Preferably, according to the invention, the tank also includes an inlet for the return of the excess substance coming from the SCR system. This inlet is preferably represented by a straw co-molded into the tank wall and equipped with a connection joint outside the tank for connecting a return pipe coming from the SRC system. This straw is preferably made of plastic, for example the same plastic material with which the tank is made, or of metal or other material. Preferably, said straw is located near the portion of the wall to which the first heating unit is fixed and preferably on the upper face of the tank.

Brief Description of the Figures

In the following description, some preferred embodiments of the invention will be described, with reference to the attached figures in which:

Fig.1 is a perspective view of a tank in accordance with a first embodiment of the invention;

Fig.2 is a sectional view along a first vertical plane of the tank of Fig.1; - Fig.3 is an enlarged view of a detail of Fig.2;

Fig.4 is a sectional view along a second vertical plane rotated by 90 ° of the tank of Fig.1;

Fig.5 is an enlarged view of a detail of Fig.4;

Fig.6 is a sectional view of the withdrawal unit of the tank of Fig.1;

- Fig.7 is a bottom plan view of the pickup unit of Fig.6;

Fig.8 is a side view of the withdrawal unit of Fig.6;

Fig.9 is a sectional view along a vertical plane of a tank in accordance with a second embodiment of the invention;

Fig.10 is an enlarged view of a detail of Fig.9;

- Fig.11 is a perspective view of the withdrawal unit of the tank of Fig.9;

Fig.12 is a perspective view from above of the sampling unit of Fig.11;

Fig. 13 is an exploded perspective view of the withdrawal unit in accordance with the first embodiment of the invention;

Fig.14 is a bottom plan view of the pickup unit of Fig.13;

- Fig. 15 is a side view of the heating unit equipped with a solenoid valve; Fig.16 is a sectional view according to a first vertical plane of the tank equipped with a union according to a preferred embodiment of the invention; Fig. 17 is a sectional view according to a vertical plan rotated by 90 ° of the tank of Fig.16;

- Fig.18 is a perspective view of the union of Fig.16;

Fig.19 is a sectional view along a vertical plane of the union of Fig.16; Fig.20 is an exploded view of the union of Fig.16.

In all the attached figures the same numerical references have been used to distinguish identical or functionally equivalent components.

Description of a Preferred Form of Realization

With reference to the attached figures, a preferred embodiment of a tank 11 according to the invention is illustrated. The tank 11 comprises a wall 13, made of plastic material, which defines inside it a chamber 15 of the tank. The material with which the wall 13 is made is such as to allow the tank 11 to contain a substance in the liquid state comprising, for example, a urea solution intended for a selective catalytic reduction (SCR) plant for the exhaust gases of an internal combustion engine.

Referring in particular to Fig. 1, the tank 11 is provided with a seat 71 to house a filler neck for refilling the tank 11. The seat 71 can be obtained by obtaining a cylindrical extension 71 a in the wall 13 of the tank during the molding phase of the tank. The cylindrical extension 71a extends outside the tank 11 in a substantially perpendicular direction to the upper face 35 of the tank body. Said extension surrounds a preferably circular opening, which houses the union.

With reference to Figs. 16 to 20 illustrates in detail a union 73 obtained according to a preferred embodiment of the invention. In the illustrated embodiment, an opening 75 is formed in a wall or transverse partition 75a of the extension 71a. Said wall or transverse partition 75a is obtained inside the extension 71a and extends on a plane substantially parallel, but not coincident, to the face 35 of the tank body 11. In other embodiments, the transverse partition 75a coincides with the wall 13 of the tank and therefore lies on a plane coinciding with that on which said wall 13 extends. In the illustrated embodiment, the extension 71a has a cylindrical shape with a circular section and so too the internal seat 71 is cylindrical with a circular section. Basically in the center of the transverse septum 75a there is the opening 75 for the passage of the union 73.

The union 73 comprises a plastic material body in which an external hollow portion 77 and an internal hollow portion 79 are defined. The external portion 77 has a substantially cylindrical development with a circular cross-section and comprises a laterally closed portion 77a and a laterally open portion 77b. Both the bases 77c, 77d of the outer portion 77 are open. The external open portion 77b defines a series of axial extensions 81, five in the example shown, which extend along as many generatrices starting from the laterally closed portion 77a and ending at an annular portion 77e of the open base 77d. The open portion 77b and the corresponding open base 77d house a filter net 83a, 83b capable of separating any impurities that may be present, from the flow of substance introduced into the filler 73 for filling the tank 11. The closed portion 77a of the external hollow portion 77 can be fixed, in correspondence with the open base 77c, in the opening 75 provided in the transverse wall 75a of the seat 71 of the tank 11. The fixing of said closed portion 77a in the opening 75 can take place with known means, for example interlocking with teeth which allow to remove, for example to clean the filter 83a, 83b, the external portion 77 of the union 73 from the seat 71. Alternatively it is possible to fix said external hollow portion 77 to the opening 75 in a permanent way.

The union 73 according to this preferred embodiment of the invention further comprises an internal hollow portion 79 comprising a cylindrical body with a circular cross section removably housed in the external hollow portion 77. Said internal portion 79, when housed in the external portion 77 of the union 73, it extends for the entire length of the closed portion 77a starting from the open base 77c and for a portion of the open portion 77b corresponding to approximately 1⁄4 of the length of said open portion 77b.

According to this embodiment of the invention, the internal portion 79 comprises an annular ring 85 provided with fins 87 extending axially outside said annular ring 85. The internal portion 79 can be engaged in the external portion 77 by manually rotating the internal portion 79 by means of said fins 87.

Advantageously, the union 73 comprises a filtering surface which is considerably larger than that of the current unions. The filtering surface of the union 73 is substantially given by the extension of the filter net 83a, 83b which surround the open cylindrical portion 77b and which cover the open base 77d of the body of the external portion 77.

Advantageously, the internal portion 79 is provided with an insert comprising a permanent magnet capable of cooperating with the valve provided in the urea solution dispensing gun. Ventilation slits 89 are provided in the opening 91 of the internal portion 79 surrounded by the ring nut 85, through which the proboscis of said dispensing gun is inserted.

The closed portion 77a of the external portion 77 of the union 73 can also be hooked by quick coupling into the opening 75 provided in the septum 75a.

With reference again to Figs. 1 to 5 shows a first embodiment of a tank 11 according to the invention. The tank 11 comprises a wall 13, made of plastic material, which defines inside it a chamber 15 of the tank. The material with which the wall 13 is made is such as to allow the tank 11 to contain a substance in the liquid state comprising, for example, a urea solution intended for a selective catalytic reduction (SCR) plant for the exhaust gases of an internal combustion engine. The tank 11 is equipped with at least one heating and suction or withdrawal unit 17, capable of heating the fluid contained in the tank 11, in particular to prevent it from freezing and to withdraw the fluid from the tank 11, in particular to send it to a pump suction or metering unit of a selective catalytic reduction (SCR) system for exhaust gases.

The heating and sampling unit 17 comprises a first unit 19, or heating unit, provided for heating the fluid in the tank 11 and a second unit 21, or sampling unit, to withdraw said fluid and send it to the SCR system circuit.

The heating unit 19 includes a heating duct 23, equipped with an inlet opening 25 and an outlet opening 27, for the transport of a heating fluid. The duct 23 develops, inside the tank 11, starting from the inlet opening 25 towards the outlet opening 27, preferably without interruption, ie preferably without connections or interruptions. In the illustrated embodiment, the duct 23 of the first unit 19 also comprises a rectilinear portion and a spiral section, in said rectilinear portion a delivery section 23 a and a return section 23 being defined and said spiral section 23 c communicates the two sections 23a, 23b. Furthermore, again with reference to the illustrated embodiment, the spiral section 23 c and the pickup unit 21 are configured in such a way that said spiral section substantially surrounds the inlet opening 31 of said pickup unit 21 defined at of the external surface of the filter 57.

The inlet and outlet openings 25,27 of the duct 23 are placed outside the tank II and can be connected, with known means, to a section of a cooling circuit of an internal combustion engine. Said endothermic engine is preferably the same engine whose exhaust gases are treated by the SCR system which receives the fluid contained in the tank.

According to the invention, advantageously, said heating units 19 and sampling units 21 are autonomous units, i.e. they are separated from each other by a portion of the tank wall in such a way that, if said portion of the tank wall is removed, said units 19 , 21 would be disjoint from each other. Advantageously, therefore, according to the invention, the heating unit 19 and the sampling unit 21 can be associated with the tank 11 in correspondence with adjacent portions, or even distant from each other of the wall 13 of the tank 11.

Referring again to Figs. 1 to 5, in accordance with a first embodiment of the invention, said units 19,21 are located distant from each other, i.e. they are associated with the wall 13 of the tank 11 in correspondence with respective portions 13a, 13b of said wall distant from each other. them, preferably on opposite parallel faces 35,37 of the tank 11. According to this embodiment of the invention, the two units 19,21 can be diametrically opposite with their respective longitudinal axes substantially parallel and preferably coaxial, for example when associated with respective parallel faces 35,37 of a parallelepiped tank 11. Or said units 19,21 can be located with their respective longitudinal axes substantially perpendicular, for example when associated with respective perpendicular faces 35,39 of a parallelepiped tank 11.

In the illustrated embodiment, the unit 19 and the unit 21 develop in a substantially rectilinear direction and are located substantially coaxial with each other. The tank 11 shown in the figures is oriented in the configuration of normal use, ie with the face 35 which houses the heating unit 19 placed above and with the face 37 which houses the pickup unit 21 below. In accordance with this arrangement, the heating unit 19 extends substantially for the entire depth of the tank 11, i.e. substantially from side to side in the vertical direction, and the sampling unit 21 extends for a portion sufficient to withdraw the liquid. from the bottom of the tank 11.

As better visible in Figs. 6 and 7, the sampling unit 21 comprises a sampling duct 29 equipped with an inlet opening 31 and an outlet opening 33. The inlet and outlet openings 31,33 of the sampling duct 29 are placed, respectively, inside and outside the tank 11. The sampling unit 21 further comprises a ring nut 41 equipped with through holes 43 for fixing, for example by means of screws, the sampling unit 21 to the wall 13 of the tank 11 in correspondence with a suitable hole provided therein. Alternatively, the ring 41 can be welded or glued to said wall 13 of the tank 11. The ring 41 also has associated temperature sensors 45a, level 45b and quality 45c of the liquid contained in the tank 11. Said sensors 45a, 45b, 45c they are associated with the ferrule 41 on the face 47 of said ferrule facing towards the inside of the tank 11 so as to face the chamber 15 enclosed by the wall 13 of the tank. On the opposite face 49 of the ring nut 41 there is a seat 51 which houses inside it an electronic card electrically connected to said sensors 45a, 45b, 45c. The electronic board is also equipped with connectors for connecting the electronic board, using a cable 53, to an electrical circuit associated with an electronic control unit for controlling the functions of the SCR system through the signals from sensors 45a, 45b, 45c.

Referring now to Figs. 9 and 10, in accordance with a second preferred embodiment of the invention, said units 19,21 are located adjacent, ie they are associated with the wall 13 of the tank in correspondence with a respective portion of the wall 13a substantially coinciding. In the illustrated embodiment, the heating unit 19 and the sampling unit 21 are placed adjacent on the same face 35 of a tank 11 with a substantially parallelepiped shape. In the example shown, unit 19 and unit 21 develop in a substantially straight direction and are located substantially coaxial with each other. The illustrated tank 11 is oriented in the configuration of normal use, ie with the face 35 which houses, in correspondence with the portion 13a, the heating unit 19 and the sampling unit 21, located above. In accordance with this arrangement, the heating unit 19 preferably extends substantially throughout the depth of the tank 11, i.e. substantially from side to side in the vertical direction. Furthermore, again with reference to this embodiment, the sampling unit 21 also extends preferably for the entire depth of the tank 11, i.e. substantially from side to side in a vertical direction, so as to allow the suction of the liquid from the tank 11, preferably up to almost complete exhaustion.

As can be seen better in Figures 11 and 12, according to this second embodiment the sampling unit 21 comprises a sampling duct 29 provided with an inlet opening 31, substantially represented by the external surface of the filter 57 and an outlet opening 33. The inlet and outlet openings 31,33 of the sampling duct 29 are located, respectively, inside and outside the tank 11. Furthermore, according to this embodiment of the invention, the sampling duct 29 extends from part by part in the vertical direction in the chamber 15, so as to allow the suction of the liquid from the tank 11, preferably until it is almost completely exhausted.

With reference in particular to Fig. 11, in this second embodiment of the invention, the temperature sensors 45a, level 45b and quality 45c of the liquid contained in the tank 11 are associated with a rod 55 which extends substantially for the entire depth of the tank 11, starting from the ring nut 41.

With reference in particular to Fig. 12, in this second embodiment, the ring nut 41 is made in a circular shape and comprises a pair of diametrically opposite recesses 41a, 41b, for the passage of the forward section 23a and the return section 23b of the duct 23. In the illustrated embodiment the duct 23 of the first unit 19 also comprises a rectilinear portion 23a, 23b and a spiral section 23c. A delivery section 23a and a return section 23b are defined in said rectilinear portion and said spiral section 23c connects the two sections 23a, 23b. Furthermore, again with reference to the illustrated embodiment, the spiral section 23c and the pick-up unit 21 are configured in such a way that said spiral section 23 c substantially surrounds the inlet opening 31 of said pick-up unit 21, substantially defined by the external surface of the filter 57.

In this embodiment, as can be appreciated in particular from Fig. 12, the unit 19 and the unit 21 are associated with the wall 13 in a substantially coincident position, while remaining two separate autonomous units. Said units 19,21 are therefore structurally connected only by the wall 13 of the tank 11.

According to a preferred embodiment of the invention, the duct 23 for heating the liquid contained in the tank 11 is associated with the wall 13 of the tank 11 directly in the molding phase of the plastic material with the co-molding technique. In this way it is advantageously possible to obtain a heat exchanger by means of the unit 19 inside the tank 11, with the desired development and shape, so as to occupy a volume sufficient to ensure the desired de-icing. For example, the duct 23 could have a development such as to extend into the chamber 15 both vertically, as illustrated for example in Fig.9, but also horizontally.

Advantageously, the wall of the duct 23 of the unit 21 can be smooth or embossed, in steel or in a suitable plastic material, even identical to that of the walls 13. Furthermore, the duct 23, which extends into the chamber 15 with its two branches of flow 23a and return 23b, and spiral connection 23c, can be free or fixed with special clips or brackets or shelves placed in the tank chamber 15, provided to avoid any displacements and / or breakages due to vibrations and oscillations during use , for example while driving a vehicle on which the tank is installed.

During the molding process for plastic materials, preferably rotational molding, a stainless steel or other material pipe is inserted and fixed inside the tank itself, subsequently connected to the cooling system of the internal combustion engine which serves as a heat exchanger.

Advantageously, according to the invention, preferably a single flange 41 carries both the temperature, level and quality sensors 45a, 45b, 45c, for controlling the parameters of the liquid contained in the tank and the electronic apparatus consisting of the board electronics housed in the seat 51, which transmits the signals coming from said sensors 45a, 45b, 45c to the electric circuit to the vehicle by means of an integrated electric connection.

Furthermore, again according to the invention, said flange 41 also preferably carries an integrated filter for the purification of the operating liquid contained in the tank 11, from impurities and a threaded connection at the opening 33 for the outlet of the filtered liquid.

Preferably, according to the invention, the tank 11 is also equipped with an inlet 28 for the return of the excess substance coming from the SCR system. This inlet 28 is preferably represented by a straw 28a co-molded into the wall 13 of the tank and equipped with a connection joint 28b placed outside the tank 11 for connecting a return pipe coming from the SRC system. This straw 28a is preferably made of plastic, for example the same plastic material with which the tank is made, or of metal or other material. Preferably said straw 28a is located near the portion of the wall 13a to which the first heating unit 19 is fixed and preferably on the upper face 35 of the tank 11.

Still according to the invention, moreover, the tank 11 is equipped with a vent opening 30, preferably obtained on said upper face 35 of the tank 11 and having the purpose of allowing the gases to escape into the atmosphere, to avoid the 'pressure increase inside the tank. Said opening 30 can be advantageously equipped with a filter to prevent the entry of impurities.

Referring in particular to Figs. 13 and 14 the sampling unit 21 comprises a filter 57 preferably substantially cylindrical in shape equipped with filter material 57a preferably pleated to increase the filtering surface. The filtering material 57a has a substantially toroidal development and comprises a closed bottom 57b and defines a corresponding preferably interchangeable cartridge, as better appreciated from Fig.13. In this embodiment the flange 41 is therefore provided with a hole 59 to house a cylindrical cartridge of filtering material 57a. The cylindrical cartridge of filtering material 57a can be advantageously screwed, or fixed in another way, in said hole 59.

In other embodiments, the filter 57 will be of the "for-life" type, ie it does not need to be replaced during the entire life of the vehicle. The filtering material 57a may consist, for example, of a pleated mesh or of another suitable material, the degree of filtration of the filtering material 57 may preferably range from 1 to 100 microns in order to satisfy the various requirements of use.

With reference to Fig. 15, an embodiment of the invention is illustrated in which the inlet 25 and outlet 27 of the duct 23 of the first heating unit 19 are connected to at least one solenoid valve 61. According to the invention, The solenoid valve 61 is located outside the tank 11 in contact with the wall 13 of the tank 11. In the specific case of the illustrated embodiment, the solenoid valve 61 is fixed against the portion 13a of said wall 13. Said solenoid valve 61 is susceptible to intercept the flow of the heating fluid which circulates in the duct 23 to regulate its flow rate. Typically, said fluid is the fluid of the cooling circuit of the endothermic engine, whose exhaust system is equipped with an SCR system to which the fluid contained in the tank 11 is sent. The solenoid valve 61 is equipped with a connector 63 for connecting the solenoid valve 61 to an electric circuit associated with an electronic control unit.

Industrial applicability

The tank according to the invention finds advantageous industrial application since it can be installed on board vehicles powered by internal combustion engines, to contain a fluid in a liquid state, destined for a selective catalytic reduction (SRC) system of the engine exhaust system. endothermic.

The invention as described and illustrated is susceptible of numerous variations and modifications, falling within the same inventive principle.

Claims (10)

CLAIMS 1. Tank (11) equipped with a filler neck (73) comprising a wall (13) in plastic material defining inside it a chamber (15) of the tank and a group (17) for heating and drawing the fluid contained in the tank, in which said union (73) comprises a body made of plastic material in which an external hollow portion (77) and an internal hollow portion (79) are defined and in which the external hollow portion (77) comprises a cylindrical portion (77b) of larger section than that of the internal portion (79) and equipped with at least one side opening which houses a filtering net (83a). 2. Reservoir according to claim 1, wherein the outer portion (77) comprises open opposite bases (77c, 77d) and has a substantially cylindrical development with a circular cross-section and comprises a laterally closed portion (77a) and an open portion laterally (77b), said laterally open portion (77b) and the open base (77d) of said laterally open portion (77b) being equipped with a filtering mesh (83a, 83b). 3. Reservoir according to claim 2, in which the laterally open portion (77b) is defined by a series of axial extensions (81) which extend along as many generatrices starting from the laterally closed portion (77a) and terminate at an annular portion (77e) surrounding said open base (77d) of the outer portion (77). 4. Reservoir according to claim 2 or 3, wherein the inner hollow portion (79) of the union (73) comprises a cylindrical body with a circular cross section removably housed in the outer hollow portion (77) and in which said inner portion ( 79), when housed in the external portion (77) of the union (73), extends for the entire length of the closed portion (77a) starting from the open base (77c) and for a portion of the open portion (77b) corresponding to approximately 1⁄4 of the length of said open portion (77b). 5. Reservoir according to claim 2 or 3 or 4, wherein the inner portion (79) comprises an annular ring (85) provided with fins (87) extending axially outside said annular ring (85) and in which the inner portion (79) can be engaged in or disengaged from the outer portion (77) by manually rotating the inner portion (79) by means of said tabs (87). 6. Reservoir according to any one of the preceding claims, wherein the union (73) comprises a filtering surface of at least 9550 mm <2>. 7. Tank according to any one of the preceding claims, in which the tank (11) is provided with a seat (71) capable of housing a filler (73) for filling the tank (11), obtained in a cylindrical extension ( 71a) which extends outside the tank (11) in a direction substantially perpendicular to the upper face (35) of the tank body. 8. Tank according to claim 7, in which said seat houses a circular opening (75), which houses said union (73). 9. Method for making a tank (11) equipped with a filler neck (73) comprising a wall (13) in plastic material defining inside it a chamber (15) of the tank and of a group (17) for heating and withdrawing the fluid contained in the tank, in which said union (73) comprises a body in plastic material in which an external hollow portion (77) and an internal hollow portion (79) are defined and in which the external hollow portion (77) comprises a portion cylindrical (77b) with a larger section than that of the internal portion (79) and equipped with at least one lateral opening which houses a filtering mesh (83a), in which said method comprises a step of obtaining a cylindrical extension (71a) in the wall (13) of the tank (11) during a phase of molding the tank. 10. Method according to claim 9, wherein a step is provided for associating said union (73) in said cylindrical extension (71a).