PM (particulate matter)

PM (particulate matter) is a general term for particulate matter emitted from diesel engines.
It is mainly black smoke (soot), uncombusted fuel called SOF, and components of lubricant. It consists of a substance called sulfate, which is produced from the sulfur contained in diesel fuel.
It also contains particularly fine-grained suspended particulate matter, which is produced when combustion temperatures are low and combustion is incomplete.
During combustion, fuel is injected into the cylinders and fuel and air are mixed, however, mixed states have a tendency to be uneven, and temperatures and pressures in cylinders drop during the "controlled combustion period" and the "late combustion period."
When these combustion conditions deteriorate, it causes the fuel to enter a "steamed state," which is equivalent to an incomplete combustion state, which generates particulate matter and black smoke.