Motor vehicle exhaust gas purifier, has a sheet made of relatively thick fibres between casing and purifier substrate, with means of increasing friction between sheet and substrate and-or between sheet and casing

摘要

#CMT# #/CMT# A motor vehicle exhaust gas purifier (10) comprising a longitudinal casing (12) defining a gas duct, substrate(s) (14) for gas purification in the casing (12) and a fibrous sheet (16) between (14) and (12), in which the diameters of the fibres in (16) are distributed about a central value of more than 4 microns and the purifier (10) also has means (36) of increasing the coefficient of friction (CF) between (16) and (14) and/or the CF between (16) and (12). #CMT#USE : #/CMT# As a motor vehicle exhaust gas purifier. #CMT#ADVANTAGE : #/CMT# Using fibrous sheet made of large-diameter fibres (e.g. silica or high-temperature glass fibres), keeps the purifier substrate in the correct longitudinal position in the external casing without the potential health risks presented by prior-art sheet made of small-diameter fibres. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# Longitudinal section of exhaust gas purifier (10). 12; 22, 24, 26 : outer casing with central cylindrical section and conical ends 14; 29, 30 : purification substrate (catalytic filter), with front and back ends 16 : fibrous sheet 18; 20 : gas inlet and outlet 27; 28 : wide and narrow parts of central section of casing 32; 34 : surfaces surrounding the fibrous sheet 36 : means of increasing coefficient of friction between (16) and (14) and/or between (16) and (12). #CMT#MECHANICAL ENGINEERING : #/CMT# Preferred Device: The fibres have diameters of more than 3 microns and the CF values (above) are more than 0.15. CF values may be increased by using a layer of adhesive (36) between (16) and (14) and/or between (16) and (12), preferably an inorganic adhesive, such that the substrate (14) shows an adherence of more than 10 kPa to the casing (12). CF values may also be increased by depressions on one side (34) of the casing (12) in contact with the sheet (16), preferably by usng a surface with a roughness (Ra) of more than 0.4 or by using holes with a depth of 0.1-3 mm. CF values may also be increased by means of abrasive particles between (16) and (14) and/or between (16) and (12). The fibrous sheet shows a density of 0.25-0.45 g/cm3> and the substrate (14) is a catalytic purifier.