Diagnosis and Control of Advanced Diesel Combustions using Engine Vibration Signal 2011-01-1414

Increasing demands on emissions reduction and efficiency encouraged a progressive introduction of cleaner combustion concepts. "Advanced" diesel combustions offer a high potential for simultaneous reduction of both NO_x and soot within the engine through high inlet charge dilution and mixture homogenization. However, the potential benefits of these combustions in terms of emissions are counterbalanced by their high sensitivity to in-cylinder thermodynamic conditions. This sensitivity makes the engines require closed loop combustion control with real-time information about combustion quality. The parameter widely considered as the most important for the evaluation of the combustion quality in internal combustion engines is the cylinder pressure. However, this kind of measure involves an intrusive approach to the cylinder, expensive sensors and a special mounting process. Several non-intrusive diagnostic techniques have been proposed to measure the quality of combustion in internal combustion engines. Among these techniques, those based on the analysis of vibration signal data have earned the greater success. This paper proposes a method for advanced diesel engine diagnosis and control without using in-cylinder pressure transducers. In particular, the first part of the present study aims to find real-time correlations between some combustion parameters (such as MFB50, combustion pressure peak location, etc.) and features derived from the engine block vibration signal. Then, in the second part of the paper, a possible combustion controller using the information extracted from the vibration signal is presented. The tests were carried out on a single-cylinder diesel engine equipped with a Common Rail injection system and a fully opened Electronic Control Unit.