Connector for a heatable fluid duct, in particular of an SCR system or a water injection system

This application is a National Stage Application of International Application No. PCT/IB2018/056267, filed Aug. 20, 2018, which claims benefit of Serial No. 10-2017-000094931, filed Aug. 22, 2017 in Italy and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above-disclosed applications.

The present invention relates to a connector for a heatable fluid duct, in particular of an SCR system or a water injection system.

However, as it will be understood, the present invention is not only directed to SCR systems, since the connector can be used in combination with a duct configured for being passed through by any fluid which is intended to be heated.

Background Art

Selective catalytic reduction (typically referred to as “SCR”) is a means of converting nitrogen oxides, also referred to as NO x with the aid of a catalyst into diatomic nitrogen (N 2 ), and water (H 2 O). A gaseous reductant, typically anhydrous ammonia, aqueous ammonia or urea, is added to a stream of flue or exhaust gas and is adsorbed onto a catalyst. Carbon dioxide, CO 2 is a reaction product when urea is used as the reductant.

Commercial selective catalytic reduction systems are typically found on large utility boilers, industrial boilers, and municipal solid waste boilers and have been shown to reduce NO x by 70-95%. More recent applications include diesel engines, such as those found on large ships, diesel locomotives, gas turbines, and automobiles.

In particular in the automotive field, an SCR system is configured for providing an aqueous solution of urea at the catalyser inlet and is located typically after the exhaust gas muffler: in the catalyser, the urea reacts with the nitrogen oxides contained in the exhaust gases, eliminating such oxides from the atmospheric emissions.

Therefore, to accomplish this process, the urea solution is generally made available in a tank, from where the solution itself can be taken to be injected into the catalyser, after having possibly been mixed with the compressed air, according to times and methods defined by an electronic control unit which accounts for various external (temperature, humidity, etc.) and internal (engine operation, number of revolutions, etc.) parameters.

The urea solution is serviceable only in liquid phase, and its freezing temperature is equal to approximately −11° C. Therefore, if the conveying means remains at temperatures under this value, the SCR system must be equipped with electric heated pipings wherein electric resistors are inserted inside or spirally wound on the pipings. The pipe connectors have not only to ensure rapid and reliable hydraulic assembly of the pipings but also to electrically connect their electric resistors to the electrical power supply and to heat the internal fluid, and this brings additional complexity, with the need to fixate the electrical connections and heating wires around the hydraulic connector, operation that is typically done by taping.

In internal combustion engines, water injection, also known as anti-detonant injection (ADI), can spray water into the incoming air or fuel-air mixture, or directly into the cylinder to cool certain parts of the induction system where “hot points” could produce premature ignition When applied to automotive gasoline engines, water injection avoids the need to inject an extra quantity of fuel to reduce NOx emissions, because low NOx emissions are guaranteed by the lower combustion temperature. This can significantly reduce fuel consumption.

Many water injection systems use a mixture of water and alcohol (often close to 50/50), with trace amounts of water-soluble oil. The water provides the primary cooling effect due to its great density and high heat absorption properties. The alcohol is combustible, and also serves as an antifreeze for the water.

DE 20 2012 102954 Ul relates to a safety clip for a heatable media line for a fluid medium.

Further disclosures of connectors for heatable fluid ducts are provided in DE 10 2009 044404 A1, DE 20 2009 012230 U1, DE 20 2008 015289 U1, DE 10 2008 025299 A1, WO 2007/032034 A1 and WO 2012/079833 A1.

It is an object of the present invention to provide a connector for a heatable fluid duct, in particular of an SCR system or a water injection system, which is capable to improve the devices manufactured in accordance with the prior art. In particular, such connector provides for an easier assembly on the heatable fluid duct.

Further technical features and advantages of the present invention will be apparent from the following detailed description, given purely by way of non-limiting example, with reference to the appended drawings, which are summarized as follow.

FIG. 1 is a perspective view of a connector which is designed according an exemplary embodiment of the present invention and which is mounted on a heatable fluid duct in order to form a heatable fluid line.

FIG. 2 is a partial lateral elevation view of the connector shown in FIG. 1 , protected by an overmoulding.

FIG. 3 is a perspective view of a connector which is designed according a further exemplary embodiment of the present invention and which is mounted on a heatable fluid duct in order to form a heatable fluid line.

FIG. 4 is an lateral elevation view of the connector shown in FIG. 3 .

FIGS. 5 and 6 are two partial perspective views of details of two connectors designed according to two exemplary embodiments of the present invention.

FIG. 7 is a perspective view of a clip to be used as part of a connector which is designed according an additional exemplary embodiment of the present invention.

FIG. 8 is a schematic view of an implementation of an electric connection to be used in a heatable fluid line which comprises a connector according to the present invention.

FIG. 9 is a partial perspective view of a clip to be used as part of the connector in FIG. 10 . which is designed according an additional exemplary embodiment of the present invention.

FIG. 10 is a partial lateral elevation with a section view of a connector designed according an additional exemplary embodiment of the present invention, and which is assembled to a heatable fluid duct in order to form a heatable fluid line.

FIG. 11 is a partial cross-sectional view of an embodiment of the present invention, wherein a fir tree structure is shown.

FIGS. 12-14 are respectively a perspective partial view, a front view, a sectional view according to lines XIV-XIV of the connector portrayed in FIGS. 9 and 10 which is assembled to a heatable fluid duct in order to form a heatable fluid line.

With reference to FIGS. 1 and 2 , a connector is indicated as a whole by the reference number 10 . Such connector is designed according to an exemplary embodiment of the present invention.

The connector 10 is intended to be used in combination with a heatable fluid duct D, so as to form a section of a heatable fluid line. During operation, the connector 10 should be capable of being heated as for the duct D.

In all the embodiments shown in the drawings, the heatable fluid line L is a part of an SCR system. As an alternative, the heatable fluid line L can be also a part of a water injection system. However, a skilled man would recognize that the present invention can be applied in several different technical fields wherein it is necessary to heat any fluid medium (thus, not only urea used typically in an SCR system or the per se known mixtures generally used in a water injection system) which is intended to be flown through a duct D.

In manner which is known per se, the duct D—to which the connector is intended to be mounted—is surrounded, internally or externally, by one or more electric heating elements which are configured to heat the fluid flowing through said duct. The duct D is preferably surrounded by a sheath 12 made of an electrically and thermally insulating material, for instance an elastomer (such as thermoplastic rubber), in order to ensure an higher degree of safety and thermal insulation. For example, such electric heating elements comprise resistive wires W.

More in detail, the connector 10 is intended to be connected, at one end 14 a , to the duct D and, at an other end 14 b , to another component of the heatable fluid delivery system. For instance, the other end 14 b can be configured to be connected to a further duct (not shown), to a dosing valve (not shown) or a tank (not shown) containing a fluid to be delivered through the heatable fluid line L. In case of an SCR system, the tank can contain an urea solution and, in case of a water injection system, the tank can contain—for example—a mixture of water and alcohol.

In particular, the ends 14 a , 14 b are designed to be coupled with the duct(s) D and/or the tank in manner which is known per se (in the examples shown: by means of quick-connectors).

With reference to FIG. 1 , for example, the other end 14 b is shaped as a female coupling to be connected to a corresponding male coupling of the element to be connected with such other end. Instead, with reference to FIG. 3 , as another example, the other end 14 b is shaped as a male coupling to be connected to a corresponding female coupling of the element to be connected with such other end.

The connector 10 comprises a thermally conductive body 14 defining a passage 16 for a fluid to be flown through the duct D. In the embodiment shown, the body 14 comprises the ends 14 a , 14 b mentioned above and between which the passage 16 is defined.

The body 14 is configured for being provided with electric heating means H situated around the passage 16 . Moreover, the connector 10 comprises a clip 18 situated around a portion of said body 14 comprising a plurality of snap-in receptacles 20 situated peripherally with respect to the body 14 and configured to fit an electric connection 22 of the electric heating means H. Owing to these technical features, when the connector 10 is assembled to the duct D, the mechanical fastening is performed and achieved in an easier manner.

In particular, as it will be shown in more detail referring to an exemplary embodiment of the present invention, the electric connection 22 of the electric heating means H connects with the electric heating elements of the duct D, in order to permit electric current to flow through the whole heatable fluid line L. In this regard, the electric heating elements W of the duct D are connected with an electric power supply circuit (not shown).

With reference in particular to the embodiment shown in FIGS. 1 and 2 , each of such snap-in receptacles 20 is configured to fit an electric connection 22 of the electric heating means H. Such electrical connection 22 has the effect to provide heating of the fluid intended to flow inside the connector 10 , in particular inside the passage 16 defined through the body 14 .

According to the present invention, the design of the connector 10 strongly simplifies the assembly operation of the whole heatable fluid line L.

In all the embodiments shown in the drawings, the clip 18 is a separate piece which is mounted on the body 14 .

In further alternative embodiments not shown, the clip can be made in a single piece with the body.

In further and less preferred alternative embodiments not shown, the clip can comprise a single snap-in receptacle situated peripherally with respect to the body and configured to fit a single electric connection.

As it can be seen in greater detail referring to the embodiment shown in FIG. 7 , the clip 18 has preferably a central hollow portion 24 which is to be fitted around a portion of the body 14 . More preferably, the hollow portion 24 is a substantially C-shaped channel which is clipped around the portion of the body 14 .

Preferably, the hollow portion 24 is coupled with an intermediate portion of the body 14 , which is situated between the ends 14 a , 14 b . Conveniently, such intermediate portion can be the sealing area between duct and connector 10 . Such sealing area can be obtained inserting a terminal part of the pipe 23 over a terminal part of the connector 10 , 25 , having the shape of a so called “fir tree” mounting portion. As a possible example, a “fir tree” structure is shown in FIG. 11 .

With reference to FIG. 1 , the clip 18 is provided with a plurality of protrusions 26 engaging with a corresponding plurality of cavities 28 of the body 14 , so as to limit or avoid at least one between a rotation or axial movement of the clip 18 relatively to the body 14 . In the above mentioned figure, a rotation of the clip 18 with respect to the body 14 is avoided. In particular, this is due to the peripherally spaced protrusions 26 around the clip 18 and engaging in the corresponding peripherally spaced cavities 28 situated on the body 14 .

With reference to FIG. 5 , the clip 18 is provided with a recess 30 engaging a corresponding projection 32 of the body 14 , so as to limit or avoid at least one between a rotation or axial movement of the clip 18 relatively to the body 14 . In this embodiment, both rotation and translation of the clip 18 with respect to the body 14 is avoided. In particular, this is due to the coupling of the substantially rectangular shape of the projection 32 into the mating recess 30 defined by an annular portion 33 of the clip 18 .

With reference to FIG. 6 , the clip 18 is provided with a stopper member 34 situated axially in front of the snap-in receptacles 20 . In this manner, it is avoided an axial movement of the electric connections 22 with respect to the clip 18 . In further alternative embodiments (not shown), the stopper member 34 can be provided on the body 14 instead of the clip 18 .

With reference to FIG. 5 , it can be understood that in an advantageous manner the projection 32 has the addition function to act as stopper member in a similar manner to the stopper member 34 shown in FIG. 6 .

In the embodiments shown, the snap-in receptacles 20 are substantially C-shaped channels situated peripherally.

In the exemplary embodiment shown in FIG. 1 , each of the C-shaped channels defining the snap-in receptacles 20 comprises a pair of substantially radial extensions (not numbered) which embraces the electric connection 22 . In addition, in a preferred manner, the protrusions 26 are axially projecting from such radial extensions.

With reference to the embodiment shown in FIG. 7 , the clip 18 is provided with a plurality of grooves 36 able to fit a wire of the electric heating means H. Such grooves 36 are open transversally towards the inside of the clip 18 . More in detail, they are defined inside the central hollow portion 24 .

In the alternative embodiment of FIG. 9 of the present invention, the grooves 36 can be open transversally towards the outside of the clip 18 . In particular, such grooves 36 are situated inside the snap-in receptacles 20 ; during the assembly the wires are fitted in the grooves 36 and then the electric connection 22 is coupled inside the snap-in receptacle 20 , thus the electric connection 22 inserted in the receptacle 20 covers and is superimposed to the wire contained in the groove 36 .

With reference to FIG. 4 , the clip 18 comprises two pairs of axial spacers 38 (two are visible also in FIG. 3 , the other two are symmetrical respect to the clip) intended to define at least a minimum distance from an abutment 40 of the duct D so as to define a gap 42 between said clip 18 and said duct D which is intended to receive a wire of the electric heating means H. So as to define the gap 42 , the axial spacers 38 can rest on the abutment 40 or be situated at a distance therefrom.

With reference to FIG. 7 , the clip is provided with a plurality of spike portions 44 having a length corresponding to the thickness of an overmoulded portion which is intended to be molded over said body and said clip and is intended to act as a shell.

With reference to FIG. 8 , is shown the design of an electric connection 22 to be prepared for being inserted in the snap-in receptacle 20 .

Preferably, such electric connection 22 is a connection protected by a sleeve, preferably a termoshrinkable sleeve. In particular, such termoshrinkable sleeve protects two terminal ends 22 a , 22 b of conductive wires W to be joined together, in particular, by means of soldering, gluing with a conductive glue or crimping with a band 46 .

According to an exemplary embodiment of the present invention, the duct D and the connector 10 are coated with an elastomer. Preferably, such elastomer is a thermoplastic elastomer.

According to an exemplary embodiment of the present invention, the duct D is coated with a corrugated tube and the connector 10 is protected by a plastic shell.

As stated above, when the connector 10 is assembled as to form the fluid line L, the body 14 and clip 18 are protected by an outer shell, which can be an overmoulded portion which is molded over said body 14 and said clip 18 or which can be a rigid casing.

With reference to FIGS. 9, 10 and 12-14 , a further embodiment is shown, wherein the C-shaped region of the central hollow portion 24 has, at one side, an axial slot 48 intended for receiving a mating axial protrusion 50 carried by the body 14 . The axial slot 48 extends only for a part of the axial length of the C-shaped region. Therefore, in other words, the connector 10 has a first greater internal diameter (or width) at a one side of the central hollow portion 24 (corresponding to the region of the axial slot 48 ) and a second smaller internal diameter (or width) at the other side of the central hollow portion 24 (corresponding to the remaining region). Likewise, the body 14 has a first greater external diameter (or width) at one side (corresponding to the region of the axial protrusion 50 ) and a second smaller internal diameter (or width) at the other side (corresponding to the remaining region). In such a manner, the clamp 18 can be assembled to the body 14 only in a predetermined direction.

Moreover, in a convenient manner, the protrusion 50 can be used to seal the connector 10 to the duct. As an example, the duct can be placed inside and attached to the connector 10 , in particular by gluing or laser welding.

In addition, one or more projections (in FIG. 13 indicated 51 , 52 ) can partially extend over the protrusion 50 so as to block the radial movement of the connector 10 , fixing it at a predetermined angular position.

Naturally, without prejudice to the principle of the present invention, the embodiments and constructional details may be widely varied with respect to what has been described and illustrated, purely by way of a non-limiting example, without thereby departing from the scope of the invention.