Characteristics and Combustibility of Particulate Matter

For meeting more stringent regulations to be imposed for reducing particulate matter (PM) in exhaust gas from diesel engines, it is required to improve performance of a trap system or other post-processing devices as well as fuel combustion efficiency of the engine itself.

In the trap system, a trap filter is equipped to collect PM from exhaust gas. For continuous use of the trap filter, a regenerative processing must be carried out to remove PM by means of forced burning when a certain amount of PM has been trapped. The combustibility or burning characteristics of collected PM have a significant effect on the regenerative processing with an electric heater/burner.

To clarify the combustibility of PM collected in the trap filter, we have examined the relationships between engine drive conditions (exhaust gas temperature), PM characteristics, and combustibility. Our examination has revealed that the combustibility of PM collected in the trap filter is primarily affected by the concentration of oxygen linked with carbon in PM rather than the concentration of soluble organic fractions (SOF).