COMBINED-TYPE EXHAUST GAS RETREATING/SOUND-ABSORBING DEVICE OF EXHAUST GAS SYSTEM FOR INTERNAL COMBUSTION ENGINE WHEREIN PREOXIDIZATION CATALYTIC CONVERTER AND AT LEAST ONE PARTICLE SEPARATOR ARRANGED IN SOUND ABSORBER ARE COMBINED

摘要

PURPOSE: A combined-type exhaust gas retreating/sound-absorbing device of an exhaust gas system for an internal combustion engine is provided to minimize the usage of platinum for a preoxidization catalytic converter and to obtain a particle conversion exceeding 50 percent. CONSTITUTION: A combined-type exhaust gas retreating/sound-absorbing device of an exhaust gas system for an internal combustion engine has a sound absorber(10). The sound absorber is spatially limited by front and rear walls and an outer wall. At lest one catalytic particle separator(16) and at lest one preoxidization catalytic converter(15) remarkably increasing nitrogen dioxide components in exhaust gas flowing are mounted inside the sound absorber. Exhaust gas to be reprocessed flows into the sound absorber through an inlet pipe(14). The exhaust gas is purified after flowing through the preoxidization catalytic converter and the particle separator and is indirectly sound-absorbed and then the exhaust gas flows out of the sound absorber. The free exhaust gas inlet area of the preoxidization catalytic converter is smaller than the free exhaust gas inlet area of the catalytic particle separator.