DE102007039048A1 - Inlet air channel, particularly for internal-combustion engine of motor vehicle, has acoustic channel section is extruded plastic tube and porous damping barrier segment is in-extruded between air-tight barrier areas - Google Patents

Abstract

The inlet air channel comprises an acoustic channel section (1) with air-tight barrier areas (2) and with a porous damping barrier segment (3). The acoustic channel section is an extruded plastic tube. The porous damping barrier segment is in-extruded between the air-tight barrier areas. The porous damping barrier segment is formed of a plastic internal part, particularly from Polyethylene (PE), Polypropylene (PP) or Polyamide (PA). An independent claim is included for a method for producing an acoustic channel section of an inlet air channel, particularly for an internal-combustion engine of a motor vehicle.

Description

Technical area

The The invention relates to an intake air duct with an acoustic duct section in particular for an internal combustion engine of a motor vehicle and a method of manufacturing the acoustic channel section.

State of the art

Internal combustion engines, in particular of motor vehicles are using an intake air duct with Supplied combustion air. The passing through the intake air passage Airflow generates intake noise caused by vortex formation and in particular by pulsations due to the timing of the Reciprocating be caused. Under certain operating conditions These intake noises in frequency and / or Volume be undesirable.

to Avoidance, modification or adaptation of the intake noise various devices are known which are equipped with damping or resonance measures or the like the intake air flow influence such that a desired frequency spectrum or volume band. Previous arrangements are complex and costly to manufacture. About that In addition, they require some space, the modern motor vehicles with numerous additional units in the engine compartment not always available stands.

From the DE 10 2004 014 314 A1 For example, a suction device with an acoustic channel section is known, which has air-impermeable wall regions and porous damping wall segments. Sound waves of the intake air flow pass through the porous segments and are thereby damped. The damping wall segments are manufactured as individual parts and used and fixed in grooves or the like of the impermeable wall areas. The soundproofing effect is good. However, the production cost is high. In particular, the possibilities for geometrically adapting the damping wall segments to the sound conditions are limited, since their mechanical load must be taken into account, in particular at the fastening edges.

Of the Invention is based on the object, an intake air duct in such a way educate that his acoustic behavior with a simple structure is improved.

These The object is achieved by an intake air duct with the features of the claim 1 solved.

Of the The invention is further based on the object, a method for producing an acoustic duct section, with which in a simple way its acoustic effectiveness at high mechanical Load capacity can be generated.

These The object is achieved by a method having the features of the claim 10 solved.

Disclosure of the invention

An intake air duct is proposed, in particular for an internal combustion engine of a motor vehicle, which has an acoustic duct section with air-impermeable wall areas and with at least one porous damping wall segment. The acoustic channel section is an extruded plastic tube. The at least one porous damping wall segment is introduced during extrusion into a plastic melt of the acoustic channel section and thereby extruded to form the airtight wall regions between them. Without any additional assembly work, the above-described extrusion process produces an acoustic channel section in the piece, which can be brought to the desired length after the plastic melt solidifies. By thermal treatment, this channel section can be provided with bends or the like. Furthermore, it is possible to apply corrugated pipes (eg in corrugator technology), which generate a bending compliancy due to their waveform. The result is a tubular acoustic channel section that can be laid almost anywhere within the available space, so that use is almost possible to any installation conditions. The sound waves of the intake noise propagating in the intake air duct, due to their pressure fluctuations, cause small portions of the intake air flow to pass through the porous damping wall segments. The porosity generates a considerable damping of the oscillating sound pressure. A special feature here is that this attenuation is effective even at very low frequencies in the range of the lower limit of hearing and also has a nearly constant attenuation behavior towards higher frequencies. This almost constant damping behavior remains over the relevant frequency range z. B. obtained above 100 Hz. The impermeable wall areas ensure on the one hand for a clean flow guidance and on the other hand for a sufficient mechanical load capacity. The embedding of the damping wall segments produced during the extrusion leads to an intimate composite material with high mechanical strength, without the need for reworking in the form of gluing, welding or otherwise. Overall, results in a geometrically simple, acoustically high Effective, mechanically stable and almost arbitrarily deployable intake system, which is optimally adapted to the acoustic requirements and can be produced with little effort.

Of the Inner diameter of the acoustic channel section is preferably in a range of including 40 mm up to and including 90 mm. Over the circumference of the acoustic channel section are appropriate five to ten damping wall segments in particular equally distributed. For small diameters for example, 40 mm are preferably five to six Damping wall segments distributed over the circumference, while at larger diameters of For example, 90 mm preferably up to ten damping wall segments over the scope are distributed. In case of irregular Pipe run also single wall segments can be used. This ensures that the absolute size individual damping wall segments does not exceed a certain extent. The load capacity of the porous damping wall segments, especially with respect to the pressure fluctuations that occur permanently supported by the intervening impermeable wall areas ensured.

For an effective compromise between sustainability and silencing effect has become an arrangement as expediently pointed out, in which the sum of all Damping wall segments based on the cross section of the acoustic channel section Overall, a cross-sectional angle of up to and including 100 ° including 140 ° and in particular of about Cover 120 °. Advantageously, the extends Sum of the damping wall segments in the longitudinal direction of the acoustic channel section over a total length, in a range of 80 mm up to and including 120 mm and in particular is about 100 mm. It can be appropriate, in the longitudinal direction only individual acoustic channel sections with the aforementioned lengths use. Advantageously, two follow in the longitudinal direction in particular the same length Dämp fungswandsegmente each other, which together have the aforementioned total length. hereby becomes the same acoustic effectiveness, the mechanical integrity improved.

For a high acoustic efficiency with adequate mechanical Resilience has an embodiment of the porous damping wall segments as plastic sintered part, in particular polyethylene (PE), polypropylene (PP) or polyamide (PA). Your porosity is advantageously less than 200 microns, and is especially in a range of 10 microns inclusive up to and including 40 μm.

The impermeable wall areas may consist of a thermosetting plastic or be made of an elastomer. Advantageously, they are made of a thermoplastic material, preferably made of polypropylene, and in particular of PPTX20 extruded. hereby are the mechanical strength as well as the dimensional stability ensured under the thermal loads within an engine compartment. At the same time results in an intimate composite material during extrusion with the material of the damping wall segments.

In an advantageous embodiment of the invention Method, the extrusion of the acoustic channel section takes place in a ring shape, wherein feed channels in particular parallel to the axis open into the ring shape. The damping wall segments be through the feed channels in the melt introduced the ring shape. The axis-parallel arrangement of To lead channels to the ring shape leads to that the damping wall segments only over their length be introduced against the adjacent melt pressure have to. Once completely melted are enclosed, the damper wall segments from the Melting current detected and automatically through the ring shape supported. Within the ring form the melt solidifies and goes thereby an intimate composite material with the prepared damping wall segments so that after solidification a nearly monolithic semi-finished product with embedded damping wall segments from the ring shape exit. With little tool and process costs high extrusion speeds with correspondingly good economy be generated.

In an advantageous embodiment, the at least one Damping wall segment as a solid in the associated Feed channel introduced. These solids can be prepared in large numbers and provided for the extrusion process, wherein they are easy to handle. In a functional Alternative sintering powder in the associated feed channel filled, wherein the at least one damping wall segment is formed in the feed channel by sintering the sintered powder. It creates an integrated manufacturing process where equally the damping wall segments and their structural unit with the impermeable wall portions be made in one operation.

In a preferred embodiment, the at least one damping wall segment is heated prior to introduction into the melt. This heating can be done for example by microwave, infrared or laser irradiation or by an electric heater. The heat supply can be used for the sintering process within the feed channel. Even with ready prepared damping wall segments in the form of solids this can Warming be appropriate. In any case, the temperature difference between the damper wall segments and the melt for the impermeable wall portions decreases, thereby improving the composite material in the subsequent extrusion process.

Brief description of the drawings

embodiments The invention are described below with reference to the drawing described. Show it:

1 a schematic side view of an inventive acoustic channel section with an extruded, sintered damping wall segments;

2 a variant of the arrangement according to 1 with two axially successive groups of damping wall segments;

3 a cross-sectional view of the arrangement according to the 1 and 2 with details of the distribution of the damping wall segments in the circumferential direction;

4 a variant of the cross-sectional shape after 3 with a single damping wall segment;

5 a schematic longitudinal sectional view of an extruder for extruding the acoustic channel section after the 1 to 4 with feed channels for damping wall segments as solids;

6 a variant of the arrangement according to 5 with sintered in the feed channels damping wall segments.

Embodiment of the invention

The 1 and 2 show in schematic side view embodiments of an inventively designed acoustic channel section 1 as part of an intake air duct not shown in detail, in particular for an internal combustion engine of a motor vehicle. The acoustic channel section 1 is designed as an approximately cylindrical tube. By this combustion air is sucked by the internal combustion engine. To attenuate the resulting, pulsating intake noise is the acoustic channel section 1 with damping wall segments 3 Mistake. These damping wall segments 3 are between air-impermeable wall areas 2 of the acoustic canal section 1 embedded by extrusion or by coextrusion. The air-impermeable wall areas 2 consist of an extruded thermoplastic, preferably of polypropylene and in particular of PPTX20. The porous Dämpfungswandseg elements 3 are formed as plastic sintered parts in particular PE, PP or PA and have a porosity with a pore size, which is preferably less than 200 microns. In the exemplary embodiments shown, the pore size ranges between 10 μm and 40 μm inclusive.

The impermeable wall areas 2 on the one hand serve the mechanical integrity of the acoustic channel section 1 and on the other hand a clean guidance of the intake air flow. The sound waves produced by the pulsation in the intake air flow lead to local pressure fluctuations, as a result of which a small part of the intake air flow vibrates through the porous damping wall segments 3 in the radial direction and enters. The porosity of the damping wall segments in this case leads to a significant attenuation of the passing air vibration, whereby a significant attenuation of the noise level of the intake air flow, but also a mechanical load occurs.

The representation after the 1 and 2 it can be seen that several damping wall segments 3 are distributed in the circumferential direction. Furthermore follow in the exemplary embodiment 2 in the longitudinal direction of the acoustic channel section 1 a total of two groups of damping wall segments 3 each other. But it may also be appropriate, in the longitudinal direction of the acoustic channel section 1 only one group of damping wall segments 3 to provide as they are in 1 is shown.

Their total length L is preferably in a range of 80 mm to 120 mm inclusive, and more preferably about 100 mm. In the advantageous development with two successive in the longitudinal direction groups of damping wall segments 3 these each have a single length L ₁ ( 2 ), which is half the total length L after 1 is. The sum of the two individual lengths L ₁ is therefore equal to the total length L. It may also be expedient, three or more successive in the longitudinal direction groups of damping wall segments 3 provided, the sum of their individual lengths according to the above examples also corresponds to the total length L. Furthermore, it may be expedient, instead of two equal individual lengths L ₁ different individual lengths of the groups of Dämpfungswandsegmenten 3 to provide, even in this case, their sum is equal to the total length L mentioned above.

3 shows a schematic cross-sectional view of the arrangement according to 1 or 2 with details of the distribution of the damper wall segments 3 between the impermeable wall areas 2 in the circumferential direction. It is recognizable, that the individual damping wall segments 3 circumferentially with each other have the same extent and also lie in the circumferential direction at the same distance from each other. However, it may also be a non-uniform distribution or non-uniform width formation of the individual damping wall segments 3 be appropriate.

An inner diameter d of the acoustic channel section 1 is within a range of 40 mm to 90 mm inclusive. With an inner diameter d of about 40 mm, preferably five to six damping wall segments 3 distributed over the circumference, while at the diameter of about 90 mm up to ten individual damping wall segments 3 are distributed over the circumference. In the embodiment shown, eight damping wall segments are examples 3 provided in the circumferential direction. This covers each individual damping wall segment 3 based on the cross-sectional area a cross-sectional angle α ₁ .

4 shows a variant of the arrangement according to 3 with only a single damping wall segment 3 , Given the circular cross-sectional configuration of the Aktusik channel section 1 covers this single damping wall segment 3 a cross-sectional angle α, which is advantageously in a range of including 100 ° to 140 ° inclusive and in the illustrated embodiment is about 120 °. The individual cross-sectional angles α _{1 are} related to 3 described group of damping wall segments 3 is equal to the cross-sectional angle α after 4 , For a total of eight distributed over the circumference damping wall segments 3 of the embodiment according to 3 is the cross-sectional angle α ₁ so about 15 °. For a different number of damping wall segments 3 of a single group distributed over the circumference, the corresponding individual cross-sectional angles α _{1 are} to be selected such that their sum equals the cross-sectional angle α a 4 is.

In the embodiments according to 3 and 4 has the acoustic channel section 1 a circular cross section. However, it may also be appropriate to have a different, for example elliptical or other suitable cross-sectional shape. The data relating to the diameter d information on the number and cross-sectional angle α of the damping wall segments 3 after the 3 and 4 are to be adapted in an equivalent way if the cross-sectional shape differs. The basis of assessment for this may be the cross-sectional area of the acoustic channel sections 1 or in particular their extent.

5 shows a schematic longitudinal sectional view of an extruder 8th with a crosshead 9 , In the cross spray head 9 is a ring shape 5 molded into which a plastic melt 4 according to an arrow 13 by means of the extruder 8th is introduced. The ring shape 5 corresponds in its geometric configuration of the cross-sectional shape of the 3 respectively. 4 , The melt 4 solidified in the ring shape 5 and is due to the pressure of the tracked melt 4 as an endless blank of the acoustic channel section 1 according to an arrow 14 from the ring shape 5 pressed out. The melt 4 consists of a thermoplastic material, preferably of polypropylene and in the illustrated embodiment of PPTX20, whereby the impermeable wall portions 2 the dashed line indicated acoustic channel section 1 be formed.

The exit of the acoustic duct section 1 opposite are feed channels 6 arranged, the paraxial in the ring shape 5 lead. The number of feed channels 6 corresponds to the number of damper wall segments 3 a distributed over the circumference group, as exemplified in 3 is shown. Accordingly, in the illustrated embodiment, a total of eight uniformly over the circumference of the ring shape 5 distributed feed channels 6 intended.

To 5 become the individual damping wall segments 3 as porous plastic sintered parts in particular made of PE, PP or PA prepared in a manner not shown and as a solid in the associated feed channels 6 according to arrows 11 introduced. About slide or other suitable means are the prepared damping wall segments 3 through the feed channels 6 in the ring shape 5 pushed. There they are melted 4 recorded and with this according to the arrows 13 . 14 through the ring shape 5 carried away. By controlled feed when tracking the damping wall segments 3 corresponding to the arrows 11 These can be with temporal distance and in the consequence also with spatial distance in the melt 4 be pressed in, so that the desired distance from one another in the longitudinal direction according to the drawing after 2 established. Upon entry of the damping wall segments 3 in the ring shape 5 These are from the melt 4 enclosed at its peripheral edges. Downstream of it, the melt solidifies 4 by cooling, as a result of which the individual damping wall segments 3 in the plastic material of the impermeable wall areas 2 are extruded. The of the individual damping wall segments 3 displaced melt 4 forms the air-impermeable wall areas 2 ,

The representation after 5 can still be seen that immediately upstream of the ring shape 5 schematically indicated heating elements 10 in the respective feed channels 6 are arranged. This he warm the damping wall segments 3 before introduction into the melt 4 , The temperature of the prepared damping wall segments 3 is at least approximately to the temperature of the melt 4 adjusted, whereby the Einxtrudieren in the ring shape 5 an intimate composite material between the plastic material of the melt 4 and the plastic material of the damping wall segments 3 arises. The heating of the damping wall segments 3 by the schematically indicated heating elements 10 can be done by microwave, infrared or laser irradiation or be brought about in a conventional manner by electrical resistance heating.

6 shows a variant of the arrangement according to 5 , at the filling channels 12 in the feed channels 6 lead. Through the filling channels 12 becomes sintered powder from the plastic material of the later damping wall segments 3 in the feed channels 6 filled. In the field of heating elements 10 act the feed channels 6 as a sintered form for the damping wall segments 3 , Under the influence of the temperature of the heating elements 10 and of pressure, for example, by slides not shown in the direction of the arrows 11 becomes the sintering powder 7 in the respective feed channels 6 to a damper wall segment 3 sintered together and then into the melt 4 the ring shape 5 introduced. In the remaining features and reference numerals, the embodiment agrees 6 with those after 5 match.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102004014314 A1 [0004]

Claims (14)

Intake air duct, in particular for an internal combustion engine of a motor vehicle, comprising an acoustic duct section ( 1 ) with air-impermeable wall areas ( 2 ) and with at least one porous damping wall segment ( 3 ), characterized in that the acoustic channel section ( 1 ) is an extruded plastic tube, and that the at least one porous damping wall segment ( 3 ) between the air-impermeable wall areas ( 2 ) is extruded. Intake air duct according to claim 1, characterized in that over the circumference of the acoustic duct section ( 1 ) five to ten damping wall segments ( 3 ) are distributed evenly in particular. Intake air duct according to claim 1 or 2, characterized in that the sum of all damper wall segments ( 3 ) relative to the cross section of the acoustic channel section ( 1 ) overall sweep a cross-sectional angle (α) of including 100 ° to and including 140 ° and in particular of about 120 °. Intake air duct according to one of claims 1 to 3, characterized in that an inner diameter (d) of the acoustic duct section ( 1 ) is within a range of 40 mm to 90 mm inclusive. Intake air duct according to one of claims 1 to 4, characterized in that the sum of the damping wall segments ( 3 ) in the longitudinal direction of the acoustic channel section ( 1 ) extends over a total length (L) ranging from 80 mm to 120 mm inclusive, and more preferably about 100 mm. Intake air duct according to claim 5, characterized in that in the longitudinal direction, in particular two equal length damping wall segments ( 3 ) follow each other, which together have the total length (L). Intake air duct according to one of claims 1 to 6, characterized in that the at least one porous damping wall segment ( 3 ) is a plastic sintered part, in particular PE, PP or PA. Intake air duct according to claim 7, characterized in that the porosity of the sintered damping wall segment ( 3 ) is less than 200 microns, and in particular in a range of from 10 microns to 40 microns inclusive. Intake air duct according to one of claims 1 to 8, characterized in that the impermeable wall areas ( 2 ) are extruded from a thermoplastic, preferably from PP, and in particular from PP TX 20. Method for producing an acoustic channel section ( 1 ) of an intake air duct, in particular for an internal combustion engine of a motor vehicle, wherein the acoustic duct section ( 1 ) air-impermeable wall areas ( 2 ) and at least one porous damper wall segment ( 3 ), wherein the acoustic channel section ( 1 ) is extruded from plastic, and wherein the at least one porous damping wall segment ( 3 ) during extrusion into a melt ( 4 ) of the acoustic channel section ( 1 ) and thereby forming the airtight wall regions ( 2 ) is extruded between them. A method according to claim 10, characterized in that the extrusion of the acoustic channel section ( 1 ) in a ring shape ( 5 ), wherein feed channels ( 6 ) in particular paraxial in the ring shape ( 5 ) and that the damping wall segments ( 3 ) through the feed channels ( 6 ) in the melt ( 4 ) of the ring shape ( 5 ). Method according to claim 10 or 11, characterized in that the at least one damping wall segment ( 3 ) as a solid in the associated feed channel ( 6 ) is introduced. Process according to claim 10 or 11, characterized in that sintering powder ( 7 ) in the associated feed channel ( 6 ) and that the at least one damping wall segment ( 3 ) in the feed channel ( 6 ) by sintering the sintered powder ( 7 ) is formed. Method according to one of claims 10 to 13, characterized in that the at least one damping wall segment ( 3 ) before introduction into the melt ( 4 ) is heated.