Diesel exhaust purification system for automobiles, comprises oxidative catalysts converting carbon monoxide, hydrocarbon and nitrogen oxides, followed by particle trap

摘要

An exhaust gas train (1) includes a catalytic converter (4) for carbon monoxide and hydrocarbons (CO, HC), an oxidation catalyst (5) converting nitric oxide (NO), and a particle trap (6). Preferred Features: The exhaust train includes a turbocharger (7) between the catalytic converter (4) and the oxidation catalyst (5) downstream. The catalytic converter is close to the engine, especially in the exhaust gas manifold (8). The oxidation catalyst (5) has zones (9). The most remote from the engine is implemented with greater specific thermal capacity than the other zone(s). The particle trap follows the oxidation catalyst directly, at a spacing less than 50 mm, and preferably less than 20 mm. Its total volume is less than 75% of an engine (2) swept volume (12). The particle trap has open through-channels including zones for swirl, stilling and/or deflection. The conversion volume (17) of the catalytic converter is at most half that of the oxidation catalyst (5). At least one of the components of the exhaust gas system, preferably every one of them, has a honeycomb structure with channels passing the exhaust gases. The components are preferably formed from partially-structured metal sheets.