30 September 1999
STT ABB of Sundsvall, Sweden announced that Volvo Bus Corporation was the first vehicle manufacturer to licence DNOx, STT's new emission control system.
STT has developed the DNOx system to reduce exhaust emissions from heavy-duty diesel engines to levels that are similar or lower than emissions from alternative fueled engines. DNOx can be installed on new diesel engines, as well as used for retrofitting of existing vehicle fleets. Certified by the Swedish authorities for use within the Environmental Zones, the system was reported to reduce CO and HC by 99%, PM by more than 90%, and NOx by 50-60% without negative effects on fuel consumption or engine durability.
The DNOx is a combined EGR - particulate trap system, involving recirculation of cooled and particulate free exhaust gases. The system includes an EGR throttle and an electronic control unit. The EGR rate is controlled as a function of engine speed and load. The system also includes an EGR cooler and a particulate filter.
Kurt Sjöblom, the CEO of STT, said, "The agreement confirms that our technology is commercially interesting and finalized. The co-operation with Volvo also means that buses already on the market can be equipped with our technology within the framework of guarantee and certification. We will now offer the system to other engine and vehicle manufacturers throughout the world".