Abstract: A combination exhaust-gas cleaner and muffler for particular use in an exhaust system of an automotive engine incorporating in the exhaust system a catalytic converter using a granular catalyst which is responsible for emission of dust particles of oxides of base or noble metal, comprising at least one centrifugal separator for separating the dust particles from the exhaust gases by imparting a centrifugal force to the stream of the exhaust gases, a dust collection chamber communicating with the centrifugal separator for collecting therein the dust particles separated from the exhaust gases and at least one silencer chamber also in communication with the centrifugal separator for dampening out noises which are borne by the exhaust gases. For the purpose of growing up the ultrafine dust into coarse particles, a particle growing chamber stuffed with a flocculent metallic material such as steel wool may be located upstream of the centrifugal separator.

Abstract: An exhaust gas reburning device has inlet ports communicating respectively with the exhaust ports of half of the combustion chambers of an engine and opening into the reaction chamber, and passageways which communicate respectively with the exhaust ports of the combustion chambers adjoining the half of the combustion chambers and fed with a combustible mixture having an air-fuel ratio different from that of a combustible mixture fed thereinto and which extend respectively to the axes of the inlet ports in the reaction chamber.