Control-oriented modeling of NO emissions of SI engines

Beginning with the first emission legislation for cars in California in the early 1970s the combination of stoichiometric combustion and exhaust gas aftertreatment using the three-way catalytic converter (TWC) became predominant. That concept enabled the industry to stay within the limits imposed by the increasingly demanding emission legislation throughout the world until today and it holds still further potential to comply with even more stringent laws to come. The oil price shock in the mid-1970s and an increasing general awareness for environmental issues directed engine research towards the search for improvements in fuel efficiency. A key to improved fuel efficiency is the reduction of the throttling losses, for instance by running the engine at lean fuel/air equivalence ratios. However, allowing the engine to run at off-stoichiometric operation requires new, more complex exhaust gas aftertreatment systems to comply with the constraints set by the emission legislation. Common to many of the new aftertreatment systems is the need for exact information on the exhaust gas composition for efficient control of the system. The contribution of this thesis is to provide a physics-based controloriented model for the estimation of the engine-out NO emission. The approach consists of (a) mapping the model parameters at nominal