Thermal insulation has two important roles to play in an exhaust system which incorporates a diesel particle filter. As has been mentioned above, regeneration of the filter depends, amongst other things, on the temperature of the exhaust gas, which must be kept above a certain threshold to enable regeneration to occur. It is possible to raise the exhaust gas temperature significantly at the inlet to the diesel particle filter by using thermal insulation to reduce the heat lost from the exhaust system upstream of this point.
The second requirement for thermal insulation arises due to the heat which diesel particle filters produce whilst they are regenerating. The internal temperatures may be in the region of 900 Centigrade (1650 Fahrenheit) and surface temperatures, whilst nowhere near this level, may still be hazardous to operators and also may radiate damaging amounts of heat into other components of the vehicle. Thermal insulation is often used to keep surface temperatures within acceptable limits.
