A recent accomplishment is a selfregenerating soot filter system developed largely for city bus application. The design consists of burner and a subsequent soot filter, which together form a complete system.The burner does not require an extra air supply as it utilizes the remaining oxygen contained in the engine exhaust gas.The burner system is microprozessor controlled and provides for automatic filter regeneration during regular vehicle operation. Since there is full exhaust flow through the filter system the design requires no moving components.A treatment of the filter body by catalyst materials is not required, neither are fuel additives for assistance with the regeneration process. This ensures highest environmental safety.Despite the high power of the burner system, the fuel consumption of approx. 0.5 1 per regeneration cycle (approx. every 6 to 8 hours) is relatively low in consideration with the overall fuel consumption. Consequently, the exhaust emission increase is likewise negligible.