Phase 1: filtering
This first phase involves catching the soot particles in a porous, silicon carbide filter.

Phase 2: elimination of particles
The second step, eliminating the soot particles, takes place in the regeneration phase. This periodic operation (after several hundred kilometres) is automatic and transparent to the driver. It simply consists in burning the soot particles that have accumulated in the filter, at a very temperature.

The sequential regeneration takes place on account of the combined action:
- Of the common rail system, which carries out a post-injection of fuel that helps increase the temperature of the exhaust to the combustion temperature for soot particles.
-Of the additive that is automatically put in very small doses into the fuel tank, which brings down the temperature to 450°C as required for burning off the soot. This unique FAP additive technique ensures Peugeot vehicles eradicate particles in a reliable manner over time.

Service periods for the filter have gone from 80,000 km to 120,000 km and are now over 180,000 km, through the combined optimisation of the filter and the additive.