NOx control with cylinder pressure based engine control systems
A reliable method of continuously determining NOx in engine exhaust gases would enable close compliance with emissions limits while maximising fuel efficiency. In the absence of suitable sensors for direct measurement, AVAT Automation uses cylinder pressure patterns as a basis for accurately estimating NOx formation.
Of the major constituents of internal combustion engine exhaust emissions, oxides of nitrogen (NOx) pose the greatest challenge, because NOx formation stands in inverse proportion to fuel consumption. This phenomenon finds expression in the “NOx-SFC trade-off” which, in simple terms, reflects the fact that the high combustion temperatures which result from complete, efficient combustion of fuel also result in the temperature peaks which favour NOx formation.
In an age of electronically controlled engines, a valuable tool for reducing NOx formation would be robust and reliable sensors for measuring NOxin engine exhausts. Their signals could be used as an input...
KeywordsNitric Oxide Cylinder Pressure Otto Cycle Indicate Mean Effective Pressure Engine Control System
Thanks go to the AiF Arbeitsgemeinschaft industrieller Forschungsvereinigungen for its support of the AVAT project in the framework of the technical development program Pro Inno II and to Dr. M. Birner and Prof. G. Wacht- meister of the LVK, Technische Universität München for their invaluable help.
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