For diesel engines HJS has developed pioneering diesel exhaust technology. The emissions from diesel engines that cause problems are nitrogen oxides (NO_x) and very fine, respirable soot particles (particulate matter or PM). It is because of these two pollutants that diesel engines continue to attract criticism, despite the fact that they are robust and economical.

HJS's aim is to work on ecological and economic principles to make an important contribution to protecting human health and the environment by developing innovative exhaust gas treatment systems for diesel engines.