Abstract
A compact diesel engine with DPNR (Diesel Particulate-NOx Reduction system) has been developed. A very low exhaust emission level, less than half of the European STEP4 regulation standard, is achieved. The new catalytic converter for DPNR consists of a monolithic substrate made of ceramics with a Ox storage reduction catalyst coating. It enables both NOx and particulate matter to be reduced simultaneously. After investigating various systems capable of creating a rich spike, a newly developed exhaust port injection system was adopted, taking into consideration NOx reduction efficiently and the influence on combustion.