Diesel Particle Filter (DPF): Description and Operation

GF14.40-D-2010HA Component Description For the Diesel Particulate Filter

- with CODE (MF4) Low-emission engine conforming to EU4 group 3

- with CODE (MS9) Engine version Euro 4





Exhaust system, shown for one-speed charging

21 Muffler
114 Diesel particulate filter (DPF)
120/1 Oxidation catalytic converter

Location

The DPF is located in the vehicle center on the underbody.

Task

The DPF filters and stores the particulate matter (particles) (PM) which arise during the combustion process in the engine. The PM is then burnt off afterwards there in the DPF regeneration phase.

Design

The DPF consists of a ceramic honeycomb filter body (monolith) made out of silicon carbide which is coated with the rare metal platinum. The passages of the diesel particulate filter are opened alternatively at front and rear and are separated from each other through the porous filter walls of the honeycomb filter body.





Schematic representation

81 Exhaust gas flow
82 ceramic monolith
83 Plugs
84 Insulation
85 Housing

Function

The unfiltered exhaust gas flows through the porous ceramic honeycomb filter of the DPF. The particles are physically retained in the honeycomb filter body (monolith) of the DPF. For regeneration of the DPF, the vehicle load of the DPF is determined by the exhaust gas pressure upstream and downstream of the DPF. The signals are evaluated by the differential pressure sensor (DPF) (B28/8) and transmitted to the CDI control unit (N3/21).

Temperatures above 600°C are necessary for soot burning which are not obtained during normal operation of the diesel engine. The CDI control unit can therefore increase the exhaust gas temperature in the following way:

^ Intake air throttling
^ Late injection