Alfa Romeo 159 Training Material page 155

ENGINE
Need to replace the trap and top up additive every 120 thousand kilometres.
Without additive
FA has developed a proprietor technology employing multiple injections to sufficiently increase gas temperature to
~600°C and burn the particulate.
Advantages
More simple architecture
More reliability due to lower thermal gradients
Lower maintenance costs
Disadvantages
Higher regeneration temperature
More oil dilution
Operation
When exhaust gas enters the DPF trap, the internal channel in the element closes and the gas crosses section A
accumulating in the filtering element. After this, the particulate accumulates and a substrate starts forming in section
B dividing the gas passage from the filtering element.
The accumulation of particulate obstructs the passage of exhaust gas (section C) to raise the pressure detected by
the respective differential pressure sensor by reading the DPF input and output pressure and measuring the exact
absolute difference between the two values.
The particulate accumulation process and respective increase of exhaust gas pressure inside the DPF depends
directly on:
vehicle weight
engine displacement and power
engine emission profile.
Regeneration process
The filter is regenerated by taking the exhaust gas at DPF input to >580°C with an O2 content of > 5%.
The engine ECU controls the process by:
metering diesel (up to 5 injections in the cycle per cylinder)
controlling air (EGR, supercharger pressure).
The generation pressure can last from 8 to 12 minutes according to the vehicle type and level of obstruction. During
this phase, the specific calibration of the engine ensures that there is no disruption of output torque with respect to
normal operation. The driver will not be aware of the process and regeneration will be maintained active in all engine
running conditions.
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