DE19814772A1 - Broadband automotive noise silencer for inlet and exhaust gases - Google Patents

Abstract

A broadband noise silencer consists of a sequence of geometric shapes incorporated within a single element. The element incorporates inlet and outlet connectors, with or without recesses, grooves, widened and narrowed sections, and a series of chambers of different volume.

Description

The present invention relates to a device for reducing flow noise over a wide frequency range. Such noises occur in many areas chen the technology on such. B. in pipe flows, throttling points, etc. as well as when burning voltage engines in the intake, exhaust gas and z. B. in the air flow of turbochargers. Such are broadband flow noises with combinations of Rauschan divide and harmonics u. a. also known for air conditioning and heating systems.

The reduction of these flow noises often has to meet other requirements Be brought into line: B. flow resistance, temperature requirements or often additionally limited space available. Furthermore, we will join ter also precautions necessary to avoid deposits, e.g. B. Oil accumulation lungs or other residues.

Especially in vehicle technology because of the need to reduce consumption and Weight reduction increased demands on the modules with regard to insulation and Attenuation of disturbing noise sources can be met. Otherwise they are extremely consumption not realizing poor vehicles.

However, the acoustic solutions required must also be cost and effective Manufacturing technology to be assessed: That means functional integration and manufacturing in as few work steps as possible.

The present invention meets these requirements by a simple structure with different basic elements, z. B. a functional unit is put together in a simple manner. Several components are available as basic elements: an inlet connector ( 1 ) with or without notches ( 2 ) and cross-sectional jumps ( 3 ), one or more chamber volumes ( 4 ) and one or more pipe branches ( 5 ) on the passage pipe ( 6 ) with outlet connector ( 7 ). These pipe branches ( 5 ) can be used to tune desired effects as smooth nozzles in the manner of λ / 4 resonators ( 8 ) or as nozzle combinations ( 9 ) with one or more constrictions ( 10 ) and the resulting final volume ( 11 ) in the type of a Helmholtz resonator. The constriction ( 10 ) on the connector combination ( 9 ) can also be designed as a cross-sectional jump to reduce undesired pipe branch resonance effects.

With such an arrangement, flow noises can meet the requirements Targeted with regard to lower (through pipe branches), medium and high  Frequency ranges (chamber volumes, notches and cross-sectional jumps) largely separate be coordinated and acoustically improved.

The combination of tunable pipes with or without notches and / or cross-sectional jumps, Chamber volumes and specially tunable pipe branches offer small ab measurements broadband level reductions of 30 dB in specified frequency ranges.

Another special feature of the arrangement is the diverse and cost-effective production option. In addition to the usual die casting techniques, shell designs are also used in e.g. B. Sheet metal or plastic constructions as well as punching and embossing techniques Application:
The selected component combination allows namely z. B. a division into two halves, which can also be carried out symmetrically.

Furthermore, the arrangement can be made from one part with the help of inexpensive blow molding technology, in which case no seals are required: the tube blank to be deformed is pressurized in the surrounding tool, the cavities being inflated. The required geometric constrictions on the component are also pressed in the tool, so that webs ( 12 ) can also be formed around the contours shown. At the same time, this means that advantages in component dynamics (more rigid structures) and strength (compactness) can be obtained without additional effort, fine adjustments with regard to component dynamics also being easier to implement.

Claims (8)

1. Device for broadband lowering of flow noise, characterized by at least one basic combination consisting of a passage pipe with inlet and outlet ports, optionally additionally with or without notches and / or cross-sectional jumps, one or more chamber volumes and specially matched pipe branches. 2. Device according to claim 1, which has no depressions in the flow direction points, whereby the risk of accumulation of residues, eg. B. oil is avoided. 3. Device according to claims 1 to 2, wherein the basic combination of chamber volume mina and special pipe branches with different geometry z. B. as a round Oval or flat body, etc. can be constructed. 4. Device according to claims 1 to 3, in which by indentations in the passage tube as well as notches occur at the inlet and outlet ports, which form half-chambers. 5. Device according to claims 1 to 4, in the special pipe branches in the manner of λ / 4 resonators, Helmholtz resonators and pipe branches with constrictions be used to reduce resonance phenomena. 6. Device according to claims 1 to 5, which by z. B. select symmetrical half shells and different materials (e.g. metals, plastics) can be manufactured. 7. Device according to claims 1 to 6, the inexpensive from a part in blow molding tech nik can be executed. 8. Device according to claims 1 to 7, by remaining, production-related webs between the cavities by stiffening them at the same time and without additional effort Improvement of component dynamics and strength can be built.