DE102007058486A1 - Evaporation device for generating ammonia gas for supplying to motor vehicle exhaust system, has heating element in thermal conducting contact with evaporation section of meander-shaped channel - Google Patents

Abstract

An evaporation device (1) comprises a basic body (2) with at least one feed line (3) and at least one outflow line (4) in which at least one heating device (5) and at least one channel (6) connecting the feed line (3) to the outflow line (4), are provided. The heating element (5) is in heat-conducting contact with an evaporation section (7) of the channel (6) which follows a meandering course. Independent claims are included for the following. (1) (A) A motor vehicle with drive, generating an exhaust gas (2) (B) A method for fabricating an evaporation device.

Description

The The present invention relates to an evaporator device comprising a basic body with at least one supply line and at least one derivative, in the at least one heating element and at least one channel for connection the supply line with the discharge are provided and a method for producing an evaporator device. Such an evaporator device should be used in particular to an aqueous urea solution heat or overheat, in this way eventually To produce ammonia gas, the exhaust system of a motor vehicle can be added to convert pollutants of the exhaust gas.

Especially In diesel combustion engines, it has been proven that of the internal combustion engine produced exhaust urea in aqueous solution Add ammonia directly or after an external hydrolysis. in this connection In known processes, a hydrolysis catalyst is used, where ammonia is extracted from the urea. The aqueous urea solution becomes upstream added to the hydrolysis catalyst, converted into a gaseous state and brought into contact with the hydrolysis catalyst. The generated For example, ammonia reacts with a so-called SCR catalyst further downstream In the exhaust stream with the nitrogen oxides contained there to molecular Nitrogen and water.

at the evaporation of the aqueous urea solution is the temperature control especially difficult. This is just to be considered from the aspect that needed Quantities of urea solution on the one hand and the available ones Temperatures on the other hand during of a mobile application can vary greatly.

Becomes an evaporation is not complete achieved, can form intermediates, which may cause constipation lead the evaporator unit can. Such, unwanted, By-products are, for example, water-insoluble biuret, which is made up of isocyanic and urea forms, and cyanuric acid, which is the trimerization product the isocyanic acid represents.

Of these, Based on the object of the present invention, an evaporator device indicate the problems mentioned above at least partially solves. Especially should be given to an evaporator device, which has a compact design is and even with highly dynamic temperature load changes the promotion or generation of ammonia gas with a predetermined accuracy and completeness guaranteed. Furthermore, a corresponding method for producing a Evaporator device can be specified.

These Tasks are solved with an evaporator device according to the features of the claim 1. Further advantageous embodiments of the evaporator device are in the formulated depending claims specified. It should be noted that the individual in the claims listed Features, in any, technologically meaningful, way with each other can be combined and show further embodiments of the invention. The description, in particular in connection with the figures, further illustrates embodiments the invention.

The Evaporator device according to the invention includes a main body with at least one supply line and at least one derivative, in the at least one heating element and at least one channel for connection the supply line and the derivative is provided, wherein the at least a heating element having an evaporation section of the at least one Channels in heat-conducting Contact is and the at least one channel in this evaporation section a meandering course having.

Of the body represents, in particular, a solid component (eg wall areas are significantly thicker than the channel cross-section), while the supply line and / or the derivative preferably a dimensionally stable, tube-like is separate component. In that regard, for example, along a common longitudinal axis a supply line over a connection to the main body be fixed, in which then the channel is formed, wherein on the opposite Side of the main body the derivative is also fixed to a connection.

By this body through the channel now extends. To the energetic special Great Introduction of the thermal energy to be introduced for evaporation At least one heating element is positioned in or on the base body (Preferably, several, evenly distributed in the body integrated heating elements) that heat generated with it the duct wall at least in the so-called evaporation section can be initiated.

In addition, it is proposed here that the (preferably only) one channel has a meandering course in the evaporation section. This means in particular that the channel in the evaporation section does not extend in a straight line (eg along the longitudinal axis), but preferably has a large number of loops, loops, turns or the like. It has been found that just such a meandering course two positive effects result: on the one hand can be formed over a relatively small extension of the body a large channel length, so that a sufficient evaporation distance in a very compact design of the body is feasible. In addition, it has been found that the forced changes of direction for the fluid flowing through the channel result in faster and more complete evaporation. Thus, for example, at flow rates through the channel in the range of up to 125 milliliters per minute Verdampfungswinkungsgrade significantly above 95%, especially above 98% and thus achieve a surprisingly significant improvement in terms of a similar straight running channel.

According to one Further development of the evaporator device comprises at least the evaporation section the at least one channel at least partially at least one tube.

Under a tube is understood in particular to be an elongated hollow body, its length much larger than his cross section is. The cross section may have any shape, being a round cross section due to the good relationship between Circumference and cross-sectional area is preferred because this allows a good heat input. Prefers the at least one pipe has a wall thickness of 0.1 to 0.5 mm (millimeters), because these are a good cohesive Attachability to the basic body allowed. In particular, this allows the pouring of the tube into the body, since the wall thickness on the one hand big enough is here to pour to prevent melting of the tube, a melting of the outer layer but to allow the pipe. On the other hand, the wall thickness is so small that still a good heat transfer possible is.

According to one further advantageous embodiment of the evaporator device the tube cohesively with the main body connected.

Especially Here is a pouring or shedding the at least one tube in or with the base body advantageous. By pouring or Shed becomes a secure cohesive contact between basic body and tube, and thus reaches the evaporation section, without the column between body and evaporation section. So is a good thermal contact and thus a good heat transfer possible, allowing an effective evaporation in the evaporation section can be done. Preferably, the base body can also be used by the casting Casting material itself be formed.

• a) Stahl;
• b) Aluminium; und
• c) Titan.

According to a further advantageous development, the tube is formed from a material comprising at least one of the following substances:

• a) steel;
• b) aluminum; and
• c) titanium.

Especially then, when the shedding of the at least one tube with a substance comprising aluminum, in particular Aluminum, takes place, have steel, preferably high-temperature and corrosion-resistant steel and titanium melting points above the melting point of aluminum lie. Also an aluminum based or -making alloy with a higher melting point than aluminum is advantageous to use.

• 2.1 mehrere abwechselnd gerader Verlaufsbereiche und gekrümmte Verlaufsbereiche,
• 2.2 gekrümmte Verlaufsbereiche mit einer Erweiterung eines Kanalquerschnitts,
• 2.3 eine Kanalabschnittslänge von 300 bis 1000 mm [Millimeter],
• 2.4 einen mittleren Kanalquerschnitt von 0,2 bis 10 mm²,
• 2.5 verschieden gekrümmte Verlaufsbereiche,
• 2.6 mehrere gekrümmte Verlaufsbereich mit einer Krümmung von mindestens 90°,
• 2.7 eine Anordnung in einer Verdampferebene des Grundkörpers,
• 2.8 eine Aluminium aufweisende Kanalwand,
• 2.9 eine Titan aufweisende Kanalwand,
• 2.10 eine Kanalwand mit einer gemittelten Rautiefe R_Z im Bereich von 2 μm [Mikrometer] bis 50 μm,
• 2.11 eine hygroskopisch aktive Kanalwand und
• 2.12 mit einer Verengung eines Kanalquerschnitts.

According to a further development of the evaporator device, the at least one channel in the evaporation section has at least one of the following features:

• 2.1 several alternating straight course areas and curved course areas,
• 2.2 curved progress areas with an extension of a channel cross section,
• 2.3 a channel section length of 300 to 1000 mm [millimeter],
• 2.4 a mean channel cross-section of 0.2 to 10 mm ² ,
• 2.5 differently curved gradient areas,
• 2.6 a plurality of curved course area with a curvature of at least 90 °,
• 2.7 an arrangement in an evaporator plane of the main body,
• 2.8 an aluminum channel wall,
• 2.9 a titanium-containing channel wall,
• 2.10 a channel wall with an average roughness R _z in the range from 2 μm [micrometers] to 50 μm,
• 2.11 a hygroscopically active channel wall and
• 2.12 with a narrowing of a channel cross-section.

in the In view of the above features, it is preferable that the channel in the evaporation section at least five and preferably even has at least eight of the features, in particular a combination from the characteristics 2.1, 2.2, 2.3, 2.4, 2.7, 2.8, 2.10, 2.11.

feature 2.1 is to be understood in particular as meaning that the channel repeats has straight, in particular mutually parallel, course area, between each of which a curved course area is provided. Especially with a parallel alignment of the straight Gradient areas is the curved one Gradient area, for example, in the manner of a 180 ° turn or a two-time 900 turn (possibly with an intermediate turn shorter straight course area).

For feature 2.2 it should be noted that in the curved course region an extension of the Ka Nalquerschnitts is achieved by at least 30%, in particular at least 40%. In this case, the extension is preferably arranged in the manner of a bulge in the region of the fluidic outside of the curved course region. It is also possible for the extension to represent a continuation of the previous straight gradient region beyond the curved gradient region. Such an extension also forms a flow reservoir for a turbulent flow and thus leads to a particularly intimate contact with the hot channel wall in this area.

The Features 2.3 and 2.4 illustrate over which small heat exchange area (channel section length x mean Channel circumference) to complete Evaporation required energy can be introduced here. It is preferred that the channel in the evaporation section at least ten (10), preferably at least twenty (20), curved process areas over the specified channel section length forms.

feature 2.5 concerns z. B. a variant embodiment, in the case of no straight course areas arranged parallel to one another are formed, but in, optionally omitting the straight Gradient areas, variously curved course areas provided are. These differ, for example, by different Radii of curvature.

Around regularly one to achieve compact arrangement and at the same time a good flow characteristics It is proposed to realize a plurality of curved progress areas with a Curvature of at least 90 ° [degrees] provided. It is also particularly preferred that this Curvature as well as the entire channel in the evaporation section in a common Evaporator level of the body is located (see feature 2.7). This has the advantage of being a Such a channel is relatively easy to manufacture, moreover also a uniform temperature input in the common evaporator level is possible.

in the Regarding the material, it is suggested that the duct wall formed with aluminum - if necessary also with one (in the main body integrated and the channel wall at least partially forming) insert. It is very particularly preferred that the material components of the (With the fluid in contact) channel wall at least one Mass fraction of over 50%, especially 90%, aluminum and / or aluminum compounds include. Aluminum has particularly positive characteristics with regard to on the heat transfer and may even have a hydrolytic activity to form alumina. With regard to a particularly good heat conduction is also proposed that the surface roughness the channel wall in the range of 2 microns up to 50 μm is, in particular in a range between 5 and 20 microns. To provide a hydrolytically active channel wall may optionally (additional) Coatings be provided, in particular the formation of metallic oxides, e.g. As aluminum, titanium and / or vanadium, is preferred. Also, the formation of the channel wall with titanium (feature 2.9) is possible. titanium has a high melting temperature, in addition, oxides of titanium hydrolytically active.

According to one Further development of the evaporator device forms the at least one Channel between the at least one supply line and the evaporation section an inlet section which is offset from the evaporation section is. "Offset" includes in this In particular, a situation in which the inlet section a lower thermal influence of at least one heating element or a smaller number of heating elements is exposed. So For example, the at least one heating element may also be up extend into a neighboring region of the inlet section, the However, exposure to this channel section is then preferably reduced.

• 4.1 eine gegenüber einer Verdampferebene des Grundkörpers versetzte Lage,
• 4.2 einen mittleren Kanalquerschnitt von 0,2 bis 30 mm² [Quadratmillimeter],
• 4.3 eine Kühlvorrichtung,
• 4.4 eine galvanische Trennung.

In view of the above explanations, it is considered preferable that the at least one channel in the inlet section has at least one of the following features:

• 4.1 a staggered relative to a vaporizer plane of the body,
• 4.2 a mean channel cross section of 0.2 to 30 mm ² [square millimeters],
• 4.3 a cooling device,
• 4.4 a galvanic isolation.

considered So you can the preferred structure of the evaporator device, in the the channel in the evaporation section in a common evaporator plane is arranged, it is proposed here, the inlet section outside This level lead to the evaporation section. extends For example, the evaporator level over a longitudinal axis of the body, so can the inlet section parallel to this longitudinal axis outside be positioned at the evaporator level. Preference is given here predominantly also a liquid guided to be, here is a slightly lower average channel cross-section provided. In this case, the inlet section, for example, as a simple Drilled bore be, so that the inlet section formed at least predominantly rectilinear is.

In addition, it is also proposed that the inlet section is formed with a cooling device. Such a cooling device can be provided to the temperature in the inlet section also at to limit different operation of the heating elements. For example, if appropriate, selectively activatable Peltier elements can be provided which, if required, remove heat from the inlet section.

Furthermore is also considered advantageous, a galvanic isolation between to provide the supply line and the inlet section. With that, right now with a simultaneous provision of a galvanic isolation in the Area of the outlet section, an electrical decoupling of the the body across from adjacent components can be achieved. This can happen just then Be beneficial if a part of the body directly by electrical Electricity is heated (Ohmic resistance heating).

According to one Another variant of the Invention forms the at least one channel between the evaporation section and the at least one drain has a spout portion which is an expansion of the channel cross section. The expansion is designed in this way that here preferably a multiple, z. B. at least 4 times or even at least 10 times the previous average channel cross section is reached. This is a further relaxation of the meantime gaseous Fluids guaranteed.

• 6.1 zumindest einen hydrolytisch aktiven Reaktorraum,
• 6.2 zumindest einen Wabenkörper, der mit Aluminium aufweisenden Blechfolien eine Vielzahl von Strömungspfaden bildet,
• 6.3 eine Aufweitung in Form eines Konus zwischen dem Verdampfungsabschnitt und einem hydrolytisch aktiven Reaktorraum,
• 6.4 eine thermische Isolierung gegenüber dem wenigstens einen Heizelement.

In this connection it is preferred that the at least one channel in the outlet section has at least one of the following features:

• 6.1 at least one hydrolytically active reactor space,
• 6.2 at least one honeycomb body forming aluminum foil with a plurality of flow paths,
• 6.3 a widening in the form of a cone between the evaporation section and a hydrolytically active reactor space,
• 6.4 a thermal insulation against the at least one heating element.

Of the hydrolytically active reactor space preferably has a coating which causes a catalytically motivated hydrolysis. Come to this z. For example, alumina, titania, vanadium oxide and / or tungsten oxide or a mixture of at least two of the aforementioned Catalysts into consideration.

Around one possible intimate contact of the gas with a hydrolytically active coating to ensure it is also suggested that in the reactor space (at least) one so-called honeycomb body is provided. This is for example smooth and wavy Formed sheet metal foils arranged so that a plurality of flow paths or microchannels are formed. These flow paths can also have Verwirbelungsbereiche, where appropriate, is also a Variety of openings provided that a flow exchange ensure between the individual flow paths. The metal foils are preferred (at least on the surface in a predominant proportion) formed with aluminum. additionally can provide a correspondingly hydrolytically active coating be, for example, in the form of alumina. Especially for the Case that a honeycomb body is arranged in the reactor space, a widening in Shape of a cone to, the incoming gas evenly over the Cross section of the honeycomb body distribute, so all the flow paths equally be used for catalytic conversion. At least partially, preferably but completely, is to provide a thermal insulation around the reactor space, so that the temperature in the reactor space, optionally targeted, adjustable is.

• 7.1 mit Aluminium als Material gebildet,
• 7.2 einen zweiteiligen Aufbau mit einer zentralen Verdampferebene,
• 7.3 zumindest der Verdampfungsabschnitt des wenigstens einen Kanals ist in einer Trennfläche des Grundkörpers eingearbeitet,
• 7.4 der Einlaufabschnitt des wenigstens einen Kanals ist in nur ein erstes Teil eines zweiteiligen Grundkörpers eingebracht,
• 7.5 eine Mehrzahl Aufnahmen für jeweils wenigstens ein Heizelement.

Moreover, it is also considered advantageous that the base body has at least one of the following features:

• 7.1 formed with aluminum as a material,
• 7.2 a two-part construction with a central evaporator level,
• 7.3 at least the evaporation section of the at least one channel is incorporated in a separation surface of the base body,
• 7.4 the inlet section of the at least one channel is introduced into only a first part of a two-part main body,
• 7.5 a plurality of receptacles for each at least one heating element.

in the In view of the advantageous heat conduction properties is proposed here, the main body to a predominant Share of aluminum to produce (mass fraction eg greater than 95%). Preference is given to the basic body execute in the manner of a solid cylinder, for example a central separation along the longitudinal axis causes a dividing surface introduced between two substantially equal parts of the body is. This interface can now be used to, for example, the meandering course of the channel a surface erosion Procedure to bring. Therefor offer, for example, milling methods, Grinding process, etching process or similar Procedure.

In the transition region between the inlet section and the evaporation section, a bore can then be provided radially from the separating surface radially to the longitudinal axis, which thus forms an offset toward the inlet section of the channel. The inlet section then becomes parallel to the longitudinal axis and the separating surface in only a first one Part of the two-piece basic body incorporated. It is very particularly preferred that only one channel is provided for the flow guidance of the fluid.

Around the channel around, in particular with an equal distance to the longitudinal axis, can now several shots for in each case at least one heating element may be provided. The shots, the particular cavities can be reached, at least from one side, so that For example, the heating elements can be inserted. Basically possible, for example each section (inlet section, evaporation section, outlet section) to provide a separate heating element in each case, so that the individual sections are independent of each other the desired Temperature can be regulated. For reasons of simple construction and as a result of the here proposed activities but sometimes self-adjusting temperature gradient can also be sufficient to provide only one heating element in each receptacle, which is about all sections of the channel or at least over the inlet section and the evaporation section extends.

Furthermore It is also suggested that the at least one supply line with a Pump is connected and an unyielding wire cross-section having. The pump allows for example, a promotion of the fluid with a pressure of up to 6 bar, with regular operation a pressure of at least 2 bar should be maintained. possibly is possible, to provide a pump that can move in two directions, so that with this individual pump transported fluid to the evaporator device on the one hand but it is also possible in the other case, the Supply again to rid of fluid - especially if no more Evaporation is needed more. For the most accurate dosage possible also proposed, the line cross-section of the supply line unyielding in particular, here while the operating pressure an expansion of the diameter of at most 0.25%.

Of Furthermore, an evaporator device is proposed, in the at least one derivative with an exhaust pipe connectable is and has a perforated end area. This is in particular meaning that the derivative has an end region in which a plurality of openings is provided, through which the gas also emerge laterally to the discharge can. This perforated end can be mm in an exhaust pipe protrude, with a uniform distribution of the ammonia-containing gas over the cross section of the exhaust pipe is realized.

All The invention is particularly preferably used in a motor vehicle comprising an exhaust generating drive and at least one Exhaust pipe. It is proposed, at least one of the here To be positioned so that evaporator devices described whose supply line cooperates with a reservoir and a fluid conveyor and their derivative projects into the exhaust pipe. As fluid conveyor comes in particular a pump used.

• a) Aluminium;
• b) Titan; und
• c) Stahl

mit einem Gussmaterial vergossen wird.According to a further aspect of the present invention, a method for producing an evaporator device comprising a base body with at least one supply line and at least one discharge, in which at least one heating element and at least one channel for connecting the supply line to the discharge line is provided, wherein the at least one heating element with a vaporization section of the at least one channel in heat-conducting contact, in which at least part of the vaporization section is formed from at least one tube, the at least one tube being made of a material comprising at least one of the following substances:

• a) aluminum;
• b) titanium; and
• c) steel

is cast with a casting material.

Prefers the at least one tube is inserted into a body and with this shed. Alternatively, the body is at least partially through the casting material after casting

According to one advantageous embodiment of the method according to the invention, the material, from which the at least one tube is formed, a higher melting point on as the casting material.

Basically preferred is also an embodiment of the method in which the temperature of the Casting material during of potting so chosen that will be a melting of the outer areas the at least one tube is made so that it becomes an intimate cohesive Connection between casting material and material of the tube comes without that the inner regions of the at least one tube melt.

According to one further advantageous embodiment of the method according to the invention The casting material comprises aluminum.

This is understood to mean that aluminum or an alloy comprising aluminum is used as the casting material. In particular, the casting material is a material with a Wärmeleitfä more than 200 W / (m K) (watts per meter and Kelvin).

According to one further advantageous embodiment of the method according to the invention The fluid is flowed through the tube while it is shed.

hereby can be a tempering, especially cooling the inner surface of the at least one tube can be achieved, by means of which a melting of the pipe material over the entire thickness of the pipe, thus one Melting through, can be prevented.

• A) Luft;
• B) ein Inertgas;
• C) Sauerstoff (O2);
• D) Stickstoff (N2); und
• E) ein aus der Verdampfung eines verflüssigten Gases gewonnenes Gas.

According to a further advantageous embodiment of the method according to the invention, the fluid comprises at least one of the following substances:

• A) air;
• B) an inert gas;
• C) oxygen (O2);
• D) nitrogen (N2); and
• E) a gas obtained from the evaporation of a liquefied gas.

According to one further advantageous embodiment of the method according to the invention is at least one of the following parameters: a) the flow rate of the fluid through the pipe, b) the temperature of the fluid and the Composition of the fluid chosen so that a melting of the at least one tube is safely avoided during casting.

The Invention and the technical environment are based on the figures explained in more detail. It It should be noted that the illustrated in the figures Embodiments of the evaporator device are not intended to limit the invention. They show schematically:

1 in a three-dimensional exploded view of a first embodiment of an evaporator device,

2 : a top view of a lower, first part of a basic body,

3 a cross-section through the first part of the body according to 2 .

4 : a detail from 2 as marked there,

5 : the arrangement of an evaporator device in a motor vehicle,

6 : a variant of a honeycomb body,

7 a perspective view of a pipe;

8th to 10 : different possible configurations of a pipe and

11 : a potted pipe.

1 is intended schematically the structure of a particularly preferred embodiment of the evaporator device 1 specify, whereby the here used basic body 2 is shown unfolded for illustration. Accordingly, the basic body comprises 2 a first part 28 and a second part 29 necessary for the operation of the evaporator device 1 about their common interface 27 be joined together. In this two-part embodiment of the body 2 shows both the first part 28 as well as the second part 29 two shots each 30 for each one heating element 5 on, which extends over the entire length in the direction of the longitudinal axis 39 of the basic body 2 extends. In the right area are still the electrical connections for a, for example, with PTC resistor (PTC: positive temperature coefficient or so-called PTC thermistor) formed heating element illustrated. Starting from the dividing surface 27 are in the second part 29 the upper area of a reactor space 21 incorporated. This will be in this second part 29 only the outlet section 19 of the canal 6 formed with.

The main body 2 or the evaporator device 1 is essentially along the longitudinal axis 39 in the flow direction 40 flows through. The fluid to be treated occurs via a supply line 3 with a predetermined line cross-section 32 in the first part 28 of the basic body 2 , which is preferably made of aluminum, a. The area of the canal 6 that goes over the inlet section 16 extends, is not shown here, as this offset to the interface 27 inside the first part 28 is trained. Only in the area of the evaporation section 7 becomes the channel 6 towards the separation area 27 where he finally a meandering course within a vaporizer level 14 performs. Following this evaporation section 7 indicates the channel 6 an expansion 20 on, passing the transition into the spout section 19 realized. This expansion 20 flows into the reactor room 21 in which one here, from a thermal insulation 26 surrounded, honeycomb body 22 incorporated or positioned in the manner of a hydrolysis catalyst support body. After that is the derivative 4 hinted that a perforated end 34 having.

2 shows a plan view of the interface 27 of the first part 28 , The channel guide is oriented substantially along the longitudinal axis 39 , where the channel 6 only in the middle area to the interface 27 to be led. There the channel leads 6 a meandering course 8th from, wherein in the individual deflections each an extension 11 is provided. After now the channel 6 several times over the longitudinal axis 39 is carried away, for example, eight or ten times, he is again centric to the longitudinal axis 39 guided and then experiences a channel cross-sectional widening towards expansion 20 which ultimately enters the reactor room 21 passes.

This will once again be in cross section, as in 3 is shown clearly. It can also be seen that the channel 6 in the area of the inlet section 16 designed in the manner of a bore, so that the channel wall 15 only from the first part 28 is formed. Adjacent to this channel in the area of the inlet section 16 is also a cooler 17 , z. B. in the manner of a Peltier element, for setting a desired temperature levels, provided. In the area of the transition to the (not shown here) supply line is also a galvanic isolation 18 intended. When leaving the inlet section 16 becomes the channel 6 towards the separation area 17 led, whereby the channel 6 there in the separation area 27 is incorporated, in particular milled. Thus, in the channel wall 15 in this evaporation section 7 from both parts of the body 2 educated.

4 now illustrates in detail the meandering course 8th of the canal 6 in the evaporation section 7 , The channel 6 has a predominantly constant channel cross-section 12 on. This applies in particular to the straight course areas 9 that repeats of curved gradient areas 10 are interrupted. In the curved gradient areas 10 is in extension to the previous straight course area 9 an extension 11 intended. This allows for a relatively short channel section length 13 to cause complete evaporation. In addition, the channel wall 15 be provided with a predetermined surface roughness, which further supports the evaporation. Part of the canal wall 15 may also be hydrolytic coatings, for example alumina.

5 schematically illustrates a possible use variant of the evaporator device 1 , In the motor vehicle 35 is a drive 26 provided, for example, an internal combustion engine (in particular a diesel engine), the exhaust gas via an exhaust pipe 13 is forwarded to the environment. Here it is now proposed that, for example, aqueous urea solution in a reservoir 37 stored and on demand by means of a fluid conveyor 38 , For example, in the manner of a pump 31 , the evaporator device 1 over the supply line 3 is supplied. After evaporation and "internal" hydrolysis, the ammonia gas passes through the drain 4 , which preferably has in a preferred end region, in the exhaust pipe 33 introduced. The ammonia gas can now mix with the exhaust gas, wherein optionally still mixing elements can be provided. This mixture then meets a catalytic converter 21 , For example, a so-called SCR catalyst, so that there the nitrogen oxides can be effectively and significantly implemented.

Just in case that part of the evaporator device 1 should also include a hydrolysis catalyst, offers the integration of a, in particular metallic, honeycomb body. Such a honeycomb body 22 is in 6 exemplified. The honeycomb body 22 Can with a variety of smooth metal foils 23 and structured sheet metal foils 24 be formed, which for the fluid to be treated id flow-through flow paths 25 forms. In these flow paths 25 can then the hydrolysis catalyst z. B. be positioned in the manner of a surface coating. It is on the one hand possible to provide a separate coating, but it is also possible, for example, when the metal foils substantially comprise aluminum, so that self-generated oxide to use for conversion or hydrolysis. The honeycomb body 22 can additionally of a thermal insulation 26 be surrounded.

According to the invention, the channel 6 at least in some areas by at least one pipe 42 be formed. 7 schematically shows an example of a pipe 42 in perspective view. The pipe 42 know a wall 43 on that has an interior 44 limited. The wall 43 is preferably cohesively with the body 2 (not shown here) connected, in particular with this shed.

The at least one pipe 42 can have at least one lead 45 in the interior 44 of the pipe 42 have in, like the 8th to 10 show schematically. This forms a constriction 47 of the channel cross section 12 , The constrictions 47 are shown as examples.

The at least one projection 45 can cross-section the entire tube 42 revolve or can also be formed only in radial sub-areas, thus partially. For partial projections 45 These can each cover at least partially other peripheral areas and can in particular symmetrically opposite - like 8th shows - or offset to each other - like the 9 and 10 show - be educated. The projection height 46 the projections 45 can be homogeneous or variable. In particular, the projections 45 be so designed that their pros jump height 46 greater than half the clear width 47 of the pipe 42 in this area is, with the protrusions 45 radially asymmetric, preferably formed substantially on opposite sides and offset from each other, as this 10 shows. With a round tube 42 corresponds to the clear width 47 the pipe diameter. Basically preferred are embodiments of channels 6 which is a light expanse 47 from 0.1 to 1 mm, preferably from 0.2 to 0.5 mm.

In operation, the evaporator device 1 charged with a liquid to be evaporated. The projections 45 lead to an improved evaporation performance, since drops of the fluid to be evaporated, for example due to a vapor cushion between the drop and the wall 43 of the canal 6 or the pipe 42 through the channel 6 and / or the pipe 42 drive to the at least one projection 45 and at least partially vaporized by contact with it.

11 shows a section of a body 2 , As a channel 6 this contains a pipe 42 , which with a casting material 48 is shed. This results in a cohesive connection between the tube 42 and the body 2 , who also not shown heating elements 5 includes. Due to the cohesive connection, there is a good heat transfer from the heating elements 5 to the at least one tube 42 , The casting material 48 is preferably aluminum or aluminum-containing.

1

evaporator device

2

body

3

supply

4

derivation

5

heating element

6

channel

7

Evaporation section

8th

course

9

straight History panel

10

curved course area

11

extension

12

Channel cross section

13

Channel section length

14

evaporator plane

15

channel wall

16

inlet section

17

cooler

18

galvanic separation

19

exit section

20

widening

21

reactor chamber

22

honeycombs

23

smoothness metal sheet

24

structured metal sheet

25

flow path

26

thermal insulation

27

interface

28

first part

29

second part

30

admission

31

pump

32

Wire Gauge

33

exhaust pipe

34

end

35

motor vehicle

36

drive

37

reservoir

38

fluid conveyor

39

longitudinal axis

40

flow direction

41

converter

42

pipe

43

wall

44

inner space

45

head Start

46

protrusion height

47

narrowing

48

cast material

Claims (18)

Evaporator device ( 1 ) comprising a main body ( 2 ) with at least one supply line ( 3 ) and at least one derivation ( 4 ), in which at least one heating element ( 5 ) and at least one channel ( 6 ) for connecting the supply line ( 3 ) with the derivative ( 4 ), wherein the at least one heating element ( 5 ) with an evaporation section ( 7 ) of the at least one channel ( 6 ) is in heat-conducting contact and the at least one channel ( 6 ) in this evaporation section ( 7 ) a meandering course ( 8th ) having. Evaporator device ( 1 ) according to claim 1, wherein at least the evaporation section ( 7 ) of the at least one channel ( 6 ) at least partially comprises at least one tube. Evaporator device ( 1 ) according to claim 2, wherein the tube cohesively with the base body ( 2 ) connected is. Evaporator device ( 1 ) according to claim 2 or 3, wherein the tube is formed of a material comprising at least one of the following: a) steel; b) aluminum; and c) titanium. Evaporator device ( 1 ) according to one of the preceding claims, in which the at least one channel ( 6 ) in the evaporation section ( 7 ) too has at least one of the following features: 2.1 several alternating straight course regions ( 9 ) and curved gradient areas ( 10 ), 2.2 curved gradient areas ( 10 ) with an extension ( 11 ) of a channel cross-section ( 12 ), 2.3 a channel section length ( 13 ) of 300 to 1,000 millimeters, 2.4 a central channel cross section ( 12 ) from 0.2 to 10 square millimeters, 2.5 differently curved graduation areas ( 10 ), 2.6 several curved gradient areas ( 10 ) with a curvature of at least 90 °, 2.7 an arrangement in an evaporator plane ( 14 ) of the basic body ( 2 ) 2.8 an aluminum channel wall ( 15 ), 2.9 a titanium-containing channel wall ( 15 ), 2.10 a channel wall ( 15 ) having an average roughness Rz in the range of 2 microns to 50 microns, 2.11 a hydrolytically active channel wall ( 15 ); and 2.12 Gradient ranges ( 10 ) with a narrowing ( 47 ) of a channel cross-section ( 12 ). Evaporator device ( 1 ) according to one of the preceding claims, in which the at least one channel ( 6 ) between the at least one supply line ( 3 ) and the evaporation section ( 7 ) an inlet section ( 16 ) which leads to the evaporation section ( 7 ) is arranged offset. Evaporator device ( 1 ) according to claim 6, wherein the at least one channel ( 6 ) in the inlet section ( 16 ) has at least one of the following features: 4.1 one opposite to an evaporator plane ( 14 ) of the basic body ( 2 ) staggered position, 4.2 a central channel cross-section ( 12 ) from 0.2 to 30 square millimeters, 4.3 a cooling device ( 17 4.4) a galvanic isolation ( 18 ). Evaporator device ( 1 ) according to one of the preceding claims, wherein the at least one channel ( 6 ) between the evaporation section ( 7 ) and the at least one derivative ( 4 ) an outlet section ( 19 ) forming an expansion ( 20 ) of the channel cross-section ( 12 ). Evaporator device ( 1 ) according to claim 8, wherein the at least one channel ( 6 ) in the outlet section ( 19 ) at least one of the following features: 6.1 at least one hydrolytically active reactor space ( 21 ), 6.2 at least one honeycomb body ( 22 ), aluminum sheet metal foils ( 23 . 24 ) a plurality of flow paths ( 25 ), 6.3 an expansion ( 20 ) in the form of a cone between the evaporation section ( 7 ) and a hydrolytically active reactor space ( 21 ), 6.4 a thermal insulation ( 26 ) relative to the at least one heating element ( 5 ). Evaporator device ( 1 ) according to one of the preceding claims, in which the basic body ( 2 ) has at least one of the following features: 7.1 formed with aluminum as a material, 7.2 a two-part structure with a central evaporator level ( 14 ), 7.3 at least the evaporation section ( 7 ) of the at least one channel ( 6 ) is in a separation area ( 27 ) of the basic body ( 2 ), 7.4 the inlet section ( 16 ) of the at least one channel ( 6 ) is in only a first part ( 28 ) of a two-part basic body ( 2 ), 7.5 a plurality of images ( 30 ) for at least one heating element ( 5 ). Evaporator device ( 1 ) according to one of the preceding claims, wherein the at least one supply line ( 3 ) with a pump ( 31 ) and an unyielding line cross-section ( 32 ) having. Evaporator device ( 1 ) according to one of the preceding claims, wherein the at least one derivative ( 4 ) with an exhaust pipe ( 33 ) is connectable and a perforated end portion ( 34 ) Has. Motor vehicle ( 35 ) comprising an exhaust gas generating drive ( 36 ) and at least one exhaust pipe ( 33 ), wherein at least one evaporator device ( 1 ) is provided according to one of the preceding claims, whose supply line ( 3 ) with a storage container ( 37 ) and a fluid conveyor ( 38 ) and their derivation ( 4 ) in the exhaust pipe ( 33 protrudes. Method for producing an evaporator device ( 1 ) comprising a main body ( 2 ) with at least one supply line ( 3 ) and at least one derivation ( 4 ), in which at least one heating element ( 5 ) and at least one channel ( 6 ) for connecting the supply line ( 3 ) with the derivative ( 4 ), wherein the at least one heating element ( 5 ) with an evaporation section ( 7 ) of the at least one channel ( 6 ) in heat-conducting contact, in which at least a part of the evaporation section ( 7 ) is formed from at least one tube, wherein the at least one tube made of a material comprising at least one of the following substances: a) aluminum; b) titanium; and c) steel with a casting material ( 48 ) is shed. The method of claim 14, wherein the material from which the at least one tube out is formed, has a higher melting point than the casting material ( 48 ). A method according to claim 14 or 15, wherein the casting material ( 48 ) Aluminum. Method according to one of claims 14 to 16, wherein the tube ( 42 ) is flowed through by a fluid while it is shed. The method of claim 17, wherein the fluid is at least one of the following substances: A) air; B) an inert gas; C) Oxygen (O2); D) nitrogen (N2); and E) one from the Evaporation of a liquefied Gas recovered gas.