DE102012111492A1 - Charged air distribution system, useful for fuel-operated internal combustion engine, comprises a charged air distributor provided with a charged air pipe, and a polyamide material coating formed on a charged air guiding surface - Google Patents

Abstract

The charged air distribution system comprises a charged air distributor (12) made of polyamide material and provided with a charged air pipe (16) of polyamide material having a supply port (30) for recirculated exhaust gas. The charged air pipe comprises an opening for exhaust gas. A charged air guiding surface is arranged downstream in a direction of the charged air distributor. A polyamide material coating is formed on the surface by an adhesive. The coating comprises a crosslinked matrix polymer material comprising intercalated PTFE. The charged air distribution system comprises a charged air distributor (12) made of polyamide material and provided with a charged air pipe (16) of polyamide material having a supply port (30) for recirculated exhaust gas. The charged air pipe comprises an opening for exhaust gas. A charged air guiding surface is arranged downstream in a direction of the charged air distributor. A polyamide material coating is formed on the surface by an adhesive. The coating comprises a crosslinked matrix polymer material comprising intercalated PTFE. Components of the polymer matrix material are crosslinked by a crosslinking agent. The coating has a thermal decomposition point of >= 300[deg] C and thickness of >= 50 mu m.

Description

The invention relates to a charge air distribution system for internal combustion engines, in particular for fuel-powered internal combustion engines, comprising a charge air tube made of polyamide material leading to a charge air distributor made of polyamide material and having a feed connection for supplied exhaust gas.

Such charge air distribution systems are known from practice. In such charge air distribution systems, there are also no problems when the fuel-driven internal combustion engines are operated with a fuel which, as is common in European countries, low sulfur content.

However, such charge air distribution systems have the disadvantage that the polyamide material is chemically attacked during an operation of the internal combustion engines with a sulfur-containing or highly sulfur-containing fuel by particle deposits and aggressive substances stored in these particles, such as acids, which causes the polyamide material shows decomposition phenomena ,

The invention is therefore based on the object to improve a charge air distribution system of the generic type such that the polyamide material shows largely no such caused by chemical attack decomposition phenomena.

This object is achieved according to the invention in a charge air distribution system of the type described above in that the charge air tube has at least starting from an opening for exhaust gas and downstream in the direction of the charge air distributor Ladeluftführende surfaces formed by a coating adhering to a surface of the polyamide material coating and that the coating a crosslinked matrix polymer material and polytetrafluoroethylene dispersed uniformly distributed in this matrix polymer material.

The advantage of the solution according to the invention can be seen in the fact that the coating on the surface of the polyamide material has created the possibility of forming charge air conducting surfaces which reduce the adhesion of particles, in particular soot particles, compared to the surface of the polyamide, and on the other hand Resistant to chemical attacks, especially acid attacks.

These properties are primarily due to the polytetrafluoroethylene, wherein the matrix polymer material (hereinafter also referred to simply as matrix) serves, on the one hand to store the polytetrafluoroethylene evenly distributed and on the other hand to create a strong connection between the polytetrafluoroethylene and the polyamide material of the charge air tube.

In principle, it would be conceivable to provide the coating only in a region of the charge air tube which follows downstream of the inlet opening.

However, it is particularly favorable if the charge air-conducting surfaces of the entire charge air pipe are formed by the coating.

In principle, there would be the possibility of not providing such a coating in the charge-air distributor for the formation of the charge-air-conducting surfaces, since in the charge air distributor the particle deposits and the chemical attacks are less intense.

It is particularly favorable, however, if the charge air-conducting surfaces of the charge air distributor are formed by the coating, so that protection of the polyamide material by the coating also takes place here.

With regard to the formation of the matrix, no further details have been given so far.

Thus, one advantageous solution is that the matrix polymer material comprises a crosslinked hydrofluorocarbon-containing fluoropolymer.

Such a partially fluorinated hydrocarbon polymer may be, for example, a polyvinylidene fluoride (PVDF) (PVF2) and polyvinyl fluoride (PVF).

A particularly favorable solution provides that the matrix polymer material comprises an optionally crosslinked terpolymer.

A terpolymer may, for example, be a terpolymer of ethylene, hexafluoropropylene and vinylidene fluoride or a terpolymer of perfluoroalkoxy monomer, tetrafluoroethylene and hexafluoropropylene or combinations thereof.

A preferred terpolymer is a terpolymer of, for example, three repeating monomer units, especially tetrafluoroethylene (TFE), hexafluoropropylene (HFP) and vinylidene fluoride (VDF).

Additionally or alternatively, in a further preferred embodiment, the matrix polymer material also comprises an optionally crosslinked polyamide-imide (PAI).

In addition, it is preferably provided that the matrix comprises zinc oxide, wherein the zinc oxide serves as an accelerator or moderator in the crosslinking.

In addition, it is expediently provided that the matrix comprises zinc oxide, with zinc oxide serving as adhesion promoter, in particular for the adhesion of the matrix to the polyamide material.

In addition, it is also envisaged that the matrix optionally comprises aluminum oxide, wherein the aluminum oxide also serves as adhesion promoter for the adhesion of the matrix to the polyamide material and to the polytetrafluoroethylene (PTFE).

With regard to the crosslinking agents for forming the matrix, no further details were given in connection with the previous explanation of the individual exemplary embodiments.

Thus, one advantageous solution is that the crosslinking agent is an amide-based and / or an amino-based crosslinking agent.

Examples of such crosslinking agents include, for example, polyaminoamides, polyamines, polyamides, aminosilanes, amidosilanes or combinations of these substances.

In particular, it is provided that one or more components of the matrix polymer material are crosslinked by a diaminic crosslinking agent.

In the case that the matrix polymer material comprises a terpolymer, it may be provided that the terpolymer is crosslinked by the diamine crosslinking agent.

In addition, it can also be provided that the polyamide-imide (PAI) is crosslinked by the diamine crosslinking agent.

A preferred diaminic crosslinking agent is a crosslinking agent comprising polyamide and / or polyaminoamides.

Another possible crosslinking agent comprises, for example, triethylenetetramine (TETA).

Additionally or alternatively, another possible crosslinking agent comprises 2- (2-aminoethylamino) ethanol (AEEA).

In addition, it is envisaged that a diaminic crosslinking agent mentioned above may also comprise formaldehyde as a reaction product, possibly also as a hardener.

A commercially available suitable in the context of the invention, component of the matrix polymer material comprises a diaminisches crosslinking agent and is sold for example under the trade mark Versamid ^® (BASF SE).

With regard to the composition of the coating, no further details have been given so far.

Thus, an advantageous embodiment provides that the coating comprises from 53% by weight to 97.5% by weight of polytetrafluoroethylene (PTFE).

Further, it is preferably contemplated that the coating comprises from 2.5% to 40% by weight of matrix polymer material which is crosslinked in the coating by a crosslinking agent.

It is envisaged, for example, that the coating comprises from 2.5% by weight to 20% by weight of terpolymer.

In addition, it is possible that the coating comprises from 0% by weight to 20% by weight of polyamide-imide (PAI).

With regard to the diaminic crosslinking agent, no further details were given in connection with the previous explanation of the coating according to the invention.

Thus, a convenient solution is for the coating to comprise from 2.5% to 5% by weight of diaminic crosslinking agent crosslinked with the matrix polymer material.

Furthermore, it is preferably provided that the matrix comprises fillers. Such fillers can be formed by a wide variety of materials.

One possibility is that the matrix comprises carbon black as a filler. Alternatively or additionally, it is possible that the matrix comprises substances based on silicon carbide and / or silicon nitride as filler.

In addition, it is preferably still provided that the coating comprises 26% or less fillers, wherein the fillers are embedded in the matrix.

It is preferably provided that the coating comprises 26% or less carbon black as filler.

With regard to the temperature resistance of the coating, no further details were given in connection with the previous explanation of the individual embodiments.

So it is preferably provided that the coating has a thermal decomposition point, which is at 300 ° C or higher.

Such a thermal disintegration point is defined by the temperature at which the coating loses its integrity and properties.

Furthermore, it is preferably provided that the thickness of the coating is 15 μm or more. It is even better if the thickness of the coating is 20 μm or more.

In order to avoid excessive variations in the thickness of the coating and thereby in particular to minimize the risk of the coating peeling off, it is preferably provided that the thickness of the coating is 50 μm or less.

Further features and advantages of the invention are the subject of the following description and the drawings of some embodiments.

In the drawing show:

1 a top view of a charge air distribution system according to the invention;

2 a section along line 2-2 in 1 ;

3 a schematic representation of a section through a coating according to the invention to form a charge air-conducting surface;

Table 1 shows a list of the components from which the coating is produced by means of a crosslinking reaction according to a first example;

Table 2 shows a list of the components from which the coating is produced by means of a crosslinking reaction according to a second example;

Table 3 shows a list of the components from which the coating is formed by means of a crosslinking reaction according to a third example;

Table 4 is a list of the composition of a flowable formulation for applying the same as a film on the surface of the polyamide material according to a first example;

Table 5 is a list of the composition flowable formulation for applying the same as a film on the surface of the polyamide material according to a second example;

Table 6 is a list of the composition flowable formulation for applying the same as a film on the surface of the polyamide material according to a third example and

Table 7 Compilation of the components and their proportions in the flowable formulation provided on the surface of the polyamide material for application according to a fourth example.

An in 1 and 2 illustrated charge air distribution system 10 for internal combustion engines comprises a charge air distributor 12 , which with a flange side 14 can be attached to an internal combustion engine and thereby engages over all the charge air inlet openings of the internal combustion engine.

To the charge air manifold 12 performs a charge air pipe connected to a charge air compressor, not shown graphically 16 , which by means of a connection flange 18 connected to the charge air compressor and via a connection flange 20 with a corresponding connecting flange 22 of the charge air distributor 12 connected is.

The charge air pipe 16 also has a supply port 30 for recirculated exhaust gas, of which an exhaust gas recirculation passage 32 that leads to a mouth 34 of the charge air pipe 16 leads, through which charge air into a charge air duct 36 of the charge air pipe 16 enters and from the charge air duct 36 into a distribution channel 38 of the charge air distributor 12 is guided.

The distribution channel 38 distributes the charge air to the various charge air inlet openings of the internal combustion engine.

In the charge air distribution system according to the invention, both the charge air pipe 16 as well as the charge air distributor 12 made of polyamide material, preferably of a filled, in particular fiber-filled, polyamide material.

Such a polyamide material has a limited chemical resistance, especially when the charge air comprises exhaust gas.

In particular, when the internal combustion engine is operated with sulfur-containing fuel, acids, in particular sulfuric acid, which are present in connection with carbon black contained in the exhaust gas and which accumulate both in the charge air duct, are formed in the exhaust gas 36 as well as in the distribution channel 38 can deposit on the polyamide material decomposing acting deposits both in the charge air duct 36 as well as in the distribution channel 38 form.

According to the invention thus both the charge air duct 36 facing and preferably downstream of the mouth opening 34 to the distribution channel 38 reaching surfaces 50 and also the distribution channel 38 facing surfaces 52 of the polyamide material from which the charge air pipe 16 and the charge air manifold are made, each with a coating 40 provided, which in the charge air duct 36 a surface carrying the charge air with the exhaust gas 42 forms and which in the distribution channel 38 likewise a surface carrying the charge air with the exhaust gas 44 forms.

The coating 40 is right on the surface 50 . 52 of the polyamide material and has, as in 3 shown, a thickness D on, the 15 μm or more.

The values of the thickness D may be in the range of 15 μm to 50 μm. As in 3 represented here comprises the coating 40 one directly on the surface 50 the polyamide material adherent matrix 52 in which polytetrafluoroethylene (PTFE) 54 is stored evenly distributed.

The matrix 52 serves on the one hand the polytetrafluoroethylene (PTFE) 54 embed and bind on the other hand, the polytetrafluoroethylene (PTFE) relative to the surface 50 . 52 to fix the polyamide material.

The matrix 52 is preferably formed from crosslinked polymers of a matrix polymer material, wherein as polymer, for example, a partially fluorinated hydrocarbon polymer is provided.

It is particularly favorable if, as a polymer, the formation of the matrix 52 is crosslinked, a terpolymer is provided, in particular a so-called THV or FKM terpolymer comprises, for example with tetrafluoroethylene (TFE), hexafluoropropylene (HFT) and vinylidene fluoride (VDF) as a monomer.

In addition, the matrix embedding the polytetrafluoroethylene (PTFE) also optionally comprises polyamide-imide (PAI).

Both the terpolymer, especially the THV or FKM terpolymer, and the polyamide-imide (PAI) are crosslinked by a diamine crosslinking agent comprising, for example, triethylenetetramine (TETA) and optionally in minor amounts 2- (2-aminoethylamino) ethanol (AEEA).

On the one hand, this crosslinking agent leads to crosslinking of the components of the matrix material, ie of the terpolymer and / or the polyamideimide (PAI), and on the other hand also causes the binding to the polyamide material, in particular a PA6.6-based material in the region of its surfaces 50 . 52 ,

As commercially available component, which comprises a diaminisches crosslinking agent Versamid ^®, for example, 140 of BASF SA provided which triethylenetetramine (TETA), optionally 2- (2-aminoethylamino) ethanol (AEEA), and optionally contains formaldehyde as a reaction product, and possibly also as a curing agent ,

In addition, the matrix still contains carbon black as a filler. In addition, the matrix still contains zinc oxide, which serves as an accelerator or moderator in the cross-linking and in the matrix 52 also has the function as a liability promoter.

As a further component of the matrix is still provided alumina, which in the matrix 52 also has the effect as a liability promoter.

As a further filler silicon carbide and / or silicon nitride is still provided, which also serves as adhesion promoter.

Individual examples concerning the composition of the proportions of coating formulation (A) before crosslinking are shown in Tables 1 to 3 below.

Applying the coating 40 takes place by including the abovementioned coating formulation (A) (also called the solids content) in a solvent (B), with the proportions of solvent to solids content given by way of example in Tables 4 to 6, the viscosity for the application of the coating 40 can still be adjusted by deviation from the proportions of solvent to solid content as needed.

The total components provided in the context of an example of the coating according to the invention and preferred ranges within which the proportions in the components can vary in the solids fraction (A) are shown in Table 7.

For example, such a coating as XYLAN ^® 1290 from Whitford Ltd., 10 Christleton Court, Manor Park, Runcorn, Cheshire WA7 1ST available.

Thus, those for the coating 40 provided solid content in liquid or pasty formulation on the surfaces 50 . 52 of the polyamide material, in such a way that on the surface 50 a film remains adhered without there being dripping and runners in the film, that is, the film has substantially an optionally varying thickness, but such a small thickness as to prevent runners.

Advantageously, the mixture of solvent (B) and solid content (A) is sprayed onto the surfaces 50 . 52 by means of one over the surface 50 movable spray head.

The parts provided with the sprayed-on film, that is the charge air tube 16 and / or the charge air distributor 12 , are applied after spraying the film and at least partially drying or expelling the solvent in an oven at temperatures between 180 ° C and 260 ° C, preferably between 180 ° C and 220 ° C, more preferably between 180 ° C and 200 ° C, such that, at these temperatures, complete expulsion of the solvent results in cross-linking of the matrix polymer material in the matrix, through which secure embedding of the polytetrafluoroethylene (PTFE) and good adhesion of the resulting coating 40 on the surface 50 . 52 of the polyamide material is ensured.

This coating 40 has a thermal decay point that is above 300 ° C, and is thus more temperature stable than the polyamide material itself.

The effect of polytetrafluoroethylene (PTFE) is the adhesion of soot or other deposits on the charge air bearing surfaces 42 and 44 against the adhesion on the surface 50 . 52 is reduced to polyamide material, if not substantially prevented, and further causes the polytetrafluoroethylene (PTFE) 54 together with the matrix 52 a resistance of the coating 40 against itself on the charge air conducting surfaces 42 or 44 , in particular at the deposits, by the recirculated exhaust gas-forming acids, so that a direct contact between the forming in the charge air acids and the polyamide material, from which the charging tube 16 and the charge air manifold 12 are formed, is prevented, and thus the decomposition of the polyamide material is prevented.

Claims (27)

Charge air distribution system ( 10 ) for internal combustion engines, in particular fuel-powered internal combustion engines, comprising a charge air distributor ( 12 ) made of polyamide material leading charge air pipe ( 16 ) of polyamide material having a supply port ( 30 ) for recirculated exhaust gas, characterized in that at least the charge air pipe ( 16 ) at least starting from a mouth ( 34 ) for exhaust gas and downstream in the direction of the charge air distributor ( 12 ) air-bearing surface ( 42 ), which by a on a surface ( 50 ) of the polyamide material adhering coating ( 40 ) and that the coating ( 40 ) a crosslinked matrix polymer material ( 52 ) and in this matrix polymer material ( 52 ) evenly distributed polytetrafluoroethylene (PTFE) ( 54 ). Charge air distribution system according to claim 1, characterized in that the charge air guiding surfaces ( 42 ) of the entire charge air pipe ( 16 ) of the coating ( 40 ) are formed. Charge air distribution system according to one of the preceding claims, characterized in that the charge air-conducting surfaces ( 44 ) of the charge air distributor ( 12 ) through the coating ( 40 ) are formed. Charge air distribution system according to one of the preceding claims, characterized in that the matrix polymer material comprises a partially fluorinated hydrocarbon polymer. Charge air distribution system according to one of the preceding claims, characterized in that the matrix polymer material comprises a terpolymer. Charge air distribution system according to claim 5, characterized in that the terpolymer comprises tetrafluoroethylene (TFE), hexafluoropropylene (HFP) and vinylidene fluoride (VDF). Charge air distribution system according to one of the preceding claims, characterized in that the matrix polymer material comprises an optionally crosslinked polyamide-imide (PAI). Charge air distribution system according to one of the preceding claims, characterized in that the matrix polymer material comprises zinc oxide. Charge air distribution system according to one of the preceding claims, characterized in that the matrix polymer material comprises alumina. Charge air distribution system according to one of the preceding claims, characterized in that the matrix polymer material comprises fillers. Charge air distribution system according to claim 10, characterized in that the matrix polymer material ( 52 ) Carbon black as a filler. Charge air distribution system according to claim 10 or 11, characterized in that the matrix polymer material ( 52 ) Comprises substances based on silicon carbide and / or silicon nitride as filler. Charge air distribution system according to one of the preceding claims, characterized in that one or more components of the matrix polymer material are crosslinked by a diaminic crosslinking agent. Charge air distribution system according to claim 13, characterized in that the terpolymer and / or the polyamideimide is crosslinked by a diaminic crosslinking agent. Charge air distribution system according to claim 13 or 14, characterized in that the diaminic crosslinking agent comprises polyamide and / or polyaminoamide. Charge air distribution system according to claim 15, characterized in that the diaminic crosslinking agent comprises triethylenetetramine (TETA). Charge air distribution system according to one of claims 13 to 16, characterized in that the diaminic crosslinking agent comprises 2- (2-aminoethylamino) ethanol (AEEA). Charge air distribution system according to one of the preceding claims, characterized in that the coating ( 40 ) from 53% to 97.5% by weight polytetrafluoroethylene. Charge air distribution system according to one of the preceding claims, characterized in that the coating ( 40 ) from 2.5% to 40% by weight of matrix polymer material. Charge air distribution system according to claim 19, characterized in that the coating ( 40 ) from 2.5% to 20% by weight of terpolymer. Charge air distribution system according to claim 19 or 20, characterized in that the coating ( 40 ) from 0% to 20% by weight of polyamideimide (PAI). Charge air distribution system according to one of the preceding claims, characterized in that the coating ( 40 ) comprises from 2.5% to 5% by weight of diaminic crosslinking agent crosslinked with the matrix polymer material. Charge air distribution system according to one of the preceding claims, characterized in that the coating ( 40 ) Comprises 26% by weight or less filler. Charge air distribution system according to claim 23, characterized in that the coating ( 40 ) Comprises 26% or less carbon black as a filler. Charge air distribution system according to one of the preceding claims, characterized in that the coating ( 40 ) has a thermal decomposition point which is 300 ° C or higher. Charge air distribution system according to one of the preceding claims, characterized in that the thickness (D) of the coating ( 40 ) Is 15 μm or more. Charge air distribution system according to one of the preceding claims, characterized in that the thickness (D) of the coating ( 40 ) Is 50 μm or less.

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