Patent Description:
In <CIT> an air cleaner is disclosed, having an inlet air channel comprising an acoustic channel section with air-tight barrier areas and with a porous damping barrier segment. The acoustic channel section is an extruded plastic tube. The porous damping barrier segment is in-extruded between the air-tight barrier areas.

From <CIT> an air intake device is known, having an intake air section with an air intake duct connected to an intake for ambient air, which serves as intake air path to an engine body. A permeable aperture has an opening located within part of the air section, to connect the section to its environment, and a porous element to cover the opening.

At <CIT> a device is published having a tubular intake pipe with intake for ambient air, an air filter downstream in the intake pipe, and an air filter hose downstream of the filter, connected to a combustion chamber of an engine. Several transmission apertures closed by air-permeable elements are located in two of the components, e.g. intake pipe, filter, or hose.

<CIT> shows an air filter system for an internal combustion engine wherein a filter chamber is provided in the air filter housing to accommodate the filter element, whereby the filter chamber communicates with an inflow channel on the raw air side and with an outflow channel on the clean air side. The housing wall of the air filter housing at least one additional opening connected to the filter chamber, which is covered by an air-permeable, porous cover layer.

<CIT> displays a noise configuration device for use in motor vehicle, having an air duct provided in area within which highest acoustic pressure is present in proximity to resonant frequency of air duct which is locked with noise absorbing material.

In <CIT> a filter housing can be found including two housing shells manufactured from plastic and a filter element separates a dirty side chamber from a clean side chamber. The filter housing having a loudspeaker membrane, an electromagnetic actuator and a loudspeaker housing for accommodating the actuator.

An air cleaner is presented in <CIT> including a hollow case, a filter element, and an opening end member. The hollow case defines an expanded space; the filter element defines an upstream-side expanded space and a downstream-side expanded space in the expanded space; the opening end member is formed from a material having an air permeability.

It is an object of the invention to provide a housing for a filter element with improved acoustic properties.

It is another object of the invention to provide a filter system comprising a housing with improved acoustic properties.

One object is achieved by a housing for a filter element, in particular for an air cleaner, in particular for a combustion engine or for a fuel cell application, having an inlet in fluid connection with a raw side volume and an outlet in fluid connection with a clean side volume, the raw side volume being arranged in a first housing shell and the clean side volume being arranged in a second housing shell, the volumes being configured to be separated by the filter element when mounted in the housing. A segment of the first housing shell constitutes an outer wall of an inlet duct, the inlet duct extending into the first housing shell, the inlet duct comprising at least one acoustically effective element arranged at least partially inside the housing shell and being configured to emit acoustic noise coming through the clean side volume at least into the raw side volume.

Another object is achieved by a filter system, in particular for an air cleaner, in particular for a combustion engine or for a fuel cell application, comprising a housing, wherein a filter element, in particular an exchangeable filter element, is accommodated in the housing, the housing having an inlet in fluid connection with a raw side volume and an outlet in fluid connection with a clean side volume, the raw side volume being arranged in a first housing shell and the clean side volume being arranged in a second housing shell, the volumes being configured to be separated by the filter element when mounted in the housing, wherein a segment of the first housing shell constitutes an outer wall of an inlet duct, the inlet duct extending into the first housing shell, the inlet duct comprising at least one acoustically effective portion arranged at least partially inside the housing shell and being configured to emit acoustic noise coming through the clean side volume at least into the raw side volume.

Advantageous embodiments of the invention are described in the dependent claims, the description and the drawings.

According to an aspect of the invention, a housing for a filter element is proposed, in particular for an air cleaner, in particular for a combustion engine or for a fuel cell application, having an inlet in fluid connection with a raw side volume and an outlet in fluid connection with a clean side volume, the raw side volume being arranged in a first housing shell and the clean side volume being arranged in a second housing shell, the volumes being configured to be separated by the filter element when mounted in the housing. A segment of the first housing shell constitutes an outer wall of an inlet duct, the inlet duct extending into the first housing shell, the inlet duct comprising at least one acoustically effective element arranged at least partially inside the housing shell and being configured to emit acoustic noise coming through the clean side volume at least into the raw side volume.

By integrating the inlet duct into the housing it is possible to create a favorable acoustic communication between the inlet duct and the housing of the filter system via the at least one acoustically effective element.

Advantageously, the acoustic efficiency can be increased as well as a cost efficient housing provided.

According to the invention, at least one acoustically effective element is a damper element in the type of a porous medium. One or more patches of the porous medium may be arranged in the wall of the inlet duct. For instance in an air cleaner of a combustion engine or a fuel cell application, the engine or fuel cell noise level can be reduced with the at least one acoustically effective element and the acoustic connection with the housing. In particular, the first housing shell accommodating the raw side volume and the inlet duct may be the same part.

The porous damping element may be made of a plastic material part, particularly from materials such as polyethylene (PE), polypropylene (PP) or polyamide (PA) or mixtures therefrom.

The acoustically effective element is be arranged in the outer wall of the inlet duct. The acoustic efficiency can be increased further.

According to the invention, the inlet duct is in fluid connection with the raw side volume through an orifice. In particular the orifice may have a larger cross section than the inlet. The arrangement can be optimized for the fabrication process, such as injection molding. According to a favorable embodiment of the housing, the outer wall of the inlet duct and the first housing shell may be composed of the same material. In particular, the housing may be made of plastic material.

According to a favorable embodiment of the housing, the outer wall of the inlet duct and the first housing shell may be composed of different materials. In particular, the housing and the outer wall of the inlet duct may be made of different plastic materials. Advantageously, this allows for applications where the inlet duct has a crooked shape, in particular due to limited mounting space for the housing or other packaging requirements, e.g. in an automotive ambient.

The inlet duct extends with a tube section from the first housing shell. Favorably, the housing with the integrated inlet duct can be adapted to mounting and space requirements for the housing.

According to a favorable embodiment of the housing, the tube section may comprise a material different from the first housing shell and/or from the outer wall of the inlet duct. Favorably, the housing with the integrated inlet duct can be adapted to mounting and space requirements for the housing.

According to another aspect of the invention, a filter system is proposed, in particular for an air cleaner, in particular for a combustion engine or for a fuel cell application, comprising a housing, wherein a filter element, in particular an exchangeable filter element, is accommodated in the housing, the housing having an inlet in fluid connection with a raw side volume and an outlet in fluid connection with a clean side volume, the raw side volume being arranged in a first housing shell and the clean side volume being arranged in a second housing shell, the volumes being configured to be separated by the filter element when mounted in the housing, wherein a segment of the first housing shell constitutes an outer wall of an inlet duct, the inlet duct extending into the first housing shell, the inlet duct comprising at least one acoustically effective portion arranged at least partially inside the housing shell and being configured to emit acoustic noise coming through the clean side volume at least into the raw side volume.

By integrating the inlet duct into the housing of the filter system it is possible to create a favorable acoustic communication between the inlet duct and the housing of the filter system via the at least one acoustically effective element.

Advantageously, the acoustic efficiency of the filter system can be increased as well as a cost efficient housing provided.

At least one acoustically effective element is arranged in the outer wall of the inlet duct. The acoustical efficiency can be improved further.

The inlet is in fluid connection with the raw side volume through an orifice. In particular the orifice may have a larger cross section than the inlet. The arrangement of the filter system can be optimized for the fabrication process of the housing, such as injection molding.

According to a favorable embodiment of the filter system, the outer wall of the inlet duct and the first housing shell may be composed of the same material. In an alternative embodiment the outer wall of the inlet duct and the first housing shell may be composed of different materials. The housing of the filter system can easily be adapted to packaging and process requirements.

The inlet duct extends with a tube section from the first housing shell. The housing of the filter system can easily be adapted to packaging and mounting space requirements.

According to a favorable embodiment of the filter system, the tube section may comprise a material different from the first housing shell and/or from the outer wall of the inlet duct. The construction of the housing of the filter system can easily be adapted to packaging and process requirements.

The present invention together with the above-mentioned and other objects and advantages may best be understood from the following detailed description of the embodiments, but not restricted to the embodiments, wherein is shown in:.

In the drawings, like elements are referred to with equal reference numerals. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. Moreover, the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention.

For instance, the filter system <NUM> described in the Figures may be used as an air cleaner, in particular for a combustion engine or for a fuel cell application.

<FIG> illustrates in a cut view an embodiment of a filter system <NUM> according to the invention. The filter system <NUM> comprises a housing <NUM> for a filter element <NUM>. The filter element <NUM> may be configured generally as a flat body having, e.g., a pleated filter medium.

As can be seen in <FIG>, the housing comprises an inlet <NUM> in fluid connection with a raw side volume <NUM> and an outlet <NUM> in fluid connection with a clean side volume <NUM>. The raw side volume <NUM> is arranged in a first housing shell <NUM> and the clean side volume <NUM> is arranged in a second housing shell <NUM>. The volumes <NUM>, <NUM> are separated by the filter element <NUM>. The first and second housing shells <NUM>, <NUM> may be detachably connected to each other so that the filter element <NUM> may be removed and replaced by a new filter element <NUM>.

A segment <NUM> of the first housing shell <NUM> constitutes an outer wall <NUM> of an inlet duct <NUM>, which extends into the first housing shell <NUM>. The inlet duct <NUM> comprises at least one acoustically effective element <NUM> arranged at least partially inside the housing shell <NUM> and, in the embodiments shown, in the outer wall <NUM> of the inlet duct <NUM>, too.

The housing is connected to a noise source <NUM>, e.g. an engine, by an outlet tube <NUM>. The fluid flow from the inlet duct <NUM> to the outlet duct <NUM> is indicated by bold arrows. The noise from the noise source <NUM> travels from the outlet duct <NUM> through the filter element <NUM> to the inlet duct <NUM>.

The acoustically effective element <NUM> is a damper element made of a porous material and being configured to emit acoustic noise coming from a noise source <NUM>, such as an engine, through the clean side volume <NUM> at least into the raw side volume <NUM>. The acoustically effective element <NUM> may be made of a plastic material.

The inlet duct <NUM> is directly acoustically coupled to the raw side volume <NUM> and can effectively reduce the noise coming from source <NUM>.

The inlet duct <NUM> is in fluid connection with the raw side volume <NUM> through an orifice <NUM>. As can be seen in <FIG>, the outer wall <NUM> of the inlet duct <NUM> and the first housing shell <NUM> may be composed of the same material.

As can be seen in <FIG>, the outer wall <NUM> of the inlet duct <NUM> and the first housing shell <NUM> are composed of different materials. The outer wall <NUM> may consist of a material <NUM>.

As can be seen in <FIG>, the inlet duct <NUM> extends with a tube section <NUM> from the first housing shell <NUM>. This allows to attach the inlet duct <NUM> to a remote fluid source (not shown).

Claim 1:
A housing (<NUM>) for a filter element (<NUM>), in particular for an air cleaner,
having an inlet (<NUM>) in fluid connection with a raw side volume (<NUM>) and an outlet (<NUM>) in fluid connection with a clean side volume (<NUM>),
the raw side volume (<NUM>) being arranged in a first housing shell (<NUM>) and the clean side volume (<NUM>) being arranged in a second housing shell (<NUM>),
the volumes (<NUM>, <NUM>) being configured to be separated by the filter element (<NUM>) when mounted in the housing (<NUM>),
wherein a segment (<NUM>) of the first housing shell (<NUM>) constitutes an outer wall (<NUM>) of an inlet duct (<NUM>), the inlet duct (<NUM>) extending into the first housing shell (<NUM>),
the inlet duct (<NUM>) comprising at least one damper element (<NUM>) in the type of a porous medium as acoustically effective element (<NUM>) arranged at least partially inside the housing shell (<NUM>) and being configured to emit acoustic noise coming through the clean side volume (<NUM>) at least into the raw side volume (<NUM>), wherein the at least one damper element (<NUM>) is arranged in the outer wall (<NUM>) of the inlet duct (<NUM>) and an outer wall (<NUM>) of the first housing shell (<NUM>), wherein the inlet duct (<NUM>) is in fluid connection with the raw side volume (<NUM>) through an orifice (<NUM>), wherein the inlet duct (<NUM>) extends with a tube section (<NUM>) from the first housing shell (<NUM>).