Function of the trap oxidizer (USA) - ra14006020050x(0050)

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

Engines 602.96, 603.96/97 TURBO (Model 463.3: for deviations see introductory notes)

The trap oxidizer is installed between the exhaust manifold and exhaust gas turbocharger and is a self-regenerating filter. It is a ceramic monolith encased in sheet metal and coated with a silver alloy. This enables the oxidizing process to be performed even at low exhaust temperatures.

The passages of the filter are closed alternately, forcing the exhaust gases to flow through the porous cell walls. The solid particles trapped as a result are oxidized at various engine operating phases at a high exhaust temperature as a result of the residual oxygen which is always present in the diesel exhaust.

Fig 1: Identifying ARF Valve And Trap Oxidizer

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 2: Identifying Trap Oxidizer Flow Diagram

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Regeneration is dependent on:

Temperature
Oxygen content
Load condition of engine
Flow velocity of exhaust gases
Duration

This oxidizing process commences as from

> 360°C. If the exhaust temperatures are > 580°C for prolonged periods, the trap oxidizer is completely regenerated.

The final product which is produced as a result of the oxidation of the soot in the filter is almost exclusively carbon dioxide (CO₂ ).