SOOT REMOVAL HAPPENS AUTOMATICALLY AND UNNOTICEABLY.
Volvo's DPF system has been designed to operate with a primarily passive regeneration cycle to optimize fuel economy. In passive regeneration, the soot is stripped out of the monolith by an ongoing catalytic reaction process that uses no additional fuel and is not noticeable to the driver. The catalytic reaction is driven by high exhaust temperatures.
The entire process-which typically takes place during high speed pulls-is simple, quiet, effective and fuel efficient. Volvo has engineered its DPF and exhaust systems to enable passive regeneration as much as possible.
ADDING FUEL TO THE EXHAUST FOR A QUICK SOOT BURN.
Some truck operations, such as city pickup and delivery or refuse collection, do not generate consistently high enough exhaust temperatures to enable passive complete regeneration of the DPF.
In these cases, the DPF will periodically undergo active regeneration. In this process, a small mist of diesel fuel is injected into the exhaust stream at the turbocharger outlet; the mist travels through the exhaust pipe to wet the DPF's pre-catalyst. This causes a chemical reaction that raises DPF temperatures to the level required to convert the soot into CO2.
Active regeneration takes about 15 minutes and the operation is not noticeable to the driver. The process happens when sensors in the DPF alert the engine computer that the particulate trap is becoming full.
As with passive regeneration, a fine ash remains trapped in the DPF. The ash is easily cleaned out during routine maintenance service. Volvo expects the DPF to go for significantly more than 150,000 miles between cleaning.