Abstract
Today and even the more in the future, exhaust emission legislation is and will remain the main technology driver for the development of heavy-duty diesel engines [1]. Although we live in a globalized world, we are far from being harmonized. Thus, exhaust emission regulations - without exception - are different in the most important markets, i.e. Europe, Japan and USA. Differences refer to exhaust emission standards, introduction dates as well as testing rules. Hence, the paper will first address the different emission legislations which have to be taken into account by worldwide acting engine manufacturers, and then discuss strategic options to meet the various emission standards and the most important base-engine and exhaust aftertreatment technologies required for.