Safe operation and control of diesel particulate filters using level set methods

Abstract

Ceramic filters used to trap diesel exhaust particulates must be periodically regenerated to remove the deposited carbon. Running the engine to provide hot and reactive feedgas can initiate a reaction to remove this carbon. Under certain conditions the heat released by this reaction can be more than enough to sustain the reaction and can result in very high local temperatures, which may typically be seen to propagate down the filter as a thermal wave. Stresses in the substrate due to its thermal expansion under these conditions can cause permanent damage to the filter. Simple control relevant models have been developed to investigate when it is safe to initiate a regeneration and when it may be necessary to change the operating conditions to avoid damage to the filter. Level set methods have been used in the reachability analysis of these problems with consideration to the design of engine management strategy. © 2008 Springer London.