Emission control with two catalytic converters

The petrol engines for the new A-Class meet the requirements of the EU4 standard. These low emission levels are firstly the result of good fuel combustion, which ensures a low level of untreated emissions. Secondly the efficient emission control system makes a major contribution: from the sheet steel exhaust manifold, whose material heats up rapidly after a cold start, the exhaust gases flow through four stainless steel ducts to a catalytic converter (volume 0.7 litres) which is located close to the engine and which features a control sensor and a diagnostic sensor. This converter is complemented by a downstream catalytic converter (volume 1.3 litres) on the underbody.

In the A 200 TURBO the exhaust manifold is air-gap-insulated, and is directly welded to the turbocharger housing.