Ceramic filter element and method of manufacture

#The invention relates to a diesel particle filter with a ceramic filter body for filtering an exhaust gas stream of a diesel engine. The filter body has flat or solid segments and porous filter segments, which are provided to facilitate flow of the exhaust gas stream through the filter transversely to the face of the filter segments.

#Published Japanese patent application no. JP 63134020 A describes a ceramic filter element for an exhaust filter in an internal combustion engine that is constructed from a corrugated, spirally wound filter sheet. To manufacture the filter sheet, heat-resistant inorganic fibers in an aqueous suspension are mixed with ceramic powder and processed into a sheet. Several superimposed sheets are rolled into the desired shape of the filter body, so that honeycomb flow paths are formed between adjacent filter sheets. The filter body is subsequently fired at a high temperature.

#A disadvantage of this ceramic filter element is that it is relatively costly to manufacture. In a first process step, a filter sheet must first be produced from the suspension of heat resistant inorganic fibers and the raw ceramic powder. This filter sheet must then be processed into the desired filter shape in a second process step and finally fired in a third process step. A further disadvantage is that the inorganic fibers in the finished filter body can reduce the filtering efficiency.

#The accompanying Figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention.

#Features of the present invention, which are believed to be novel, are set forth in the drawings and more particularly in the appended claims. The invention, together with the further objects and advantages thereof, may be best understood with reference to the following description, taken in conjunction with the accompanying drawings. The drawings show a form of the invention that is presently preferred; however, the invention is not limited to the precise arrangement shown in the drawings.

#FIG. 1 shows two substrate sheets infiltrated with a ceramic slip and bonded to each other by an adhesive or a sealant, so that flow paths between the substrate sheets are sealed at one end, consistent with the present invention;

#Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.

#Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of apparatus components manufacturing methods related to a ceramic filter element which in embodiments is suitable for use as a diesel particulate filter. Accordingly, the apparatus components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

#In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.