In the last years the development of diesel particulate traps and trap regeneration systems has led to some very promising concepts. In parallel the development of diesel engine technology for passenger cars, as well as for light and heavy duty vehicles, has resulted in remarkable improvements especially regarding particulate and NOx emissions, engine performance and fuel economy.
Unfortunately, for some aspects the development and application of particulate trap systems on the one hand and diesel engine technology on the other have led to conflicting solutions.
For example, exhaust gas temperatures of at least 500 °C to 600 °C are necessary to burn off the soot that has been emitted by the engine and collected in a particulate trap. However, the increased fuel efficiency of modern TDI diesel engines and the trend to reduced average traffic speed very often cause exhaust temperatures below 200 °C at urban driving conditions. During high speed highway operation exhaust temperatures higher than 550 °C occur only seldom. Currently, there are many applications available for regeneration technology concerning passive diesel particulate trap systems. The wide range of engine operation and different compositions in exhaust, respectively, in some cases can limit fail- save operation for trap regeneration systems. Active regeneration systems (e.g. diesel fuel burners or electrical heater), that are able to cover almost the entire operating range can become very expensive. Due to the technical requirements trap regeneration systems operating in a wide range are not practical for vehicle particulate traps, either because of system costs being too high or there is limited package conditions in a vehicle.
In this paper boundary conditions of different engines and different types of vehicles in varied operation modes are published. Furthermore, the potential of combining different regeneration systems will be presented and discussed.