Soot is a product created during incomplete combustion of fuels. Generally, we can distinguish between the two types of soot accumulation.
1. Pore Accumulation
Solid particles are deposited in the pore network inside the material of the filter wall. Depending on the level of soot load and filter type, pore accumulation may in some cases constitute a 50% drop in the filter pressure, or even more.
2. Soot Cake
As the soot charge increases in the pore network, the layer of particles begins to form along the wall surface in the inlet channels, and soot cake becomes the dominant filtration mechanism.
Ash accumulates in DPF during prolonged use, as a non-flammable material left after filter regeneration and soot oxidation. Ash consists of various metal compounds derived from lubricating additives, trace elements in fuel and wear of the engine and corrosion products.
Motor Oil Contamination
Resulting from a leaky engine intake system (eg turbocharger failure). Oil gets into the filter cartridge (monolith) where it burns out.