This work constitutes one of the last steps of a comprehensive research program in which vibration sensors are used with the purpose of developing and setting up a methodology that is able to perform a real time control of the combustion process by means of non-intrusive measurements.
Previous obtained and published results have demonstrated that a direct relationship exists between in-cylinder pressure and engine block vibration signals. The analysis of the processed data have highlighted that the block vibration signal may be used to locate, in the crank–angle domain, the combustion phases (the start of the combustion, the crank angle value corresponding to the beginning of main combustion and to the in-cylinder pressure maximum value) and to quantify the in-cylinder pressure development by evaluating the pressure peak value and the pressure rise rate caused by the combustion process.
The aim of this work is to extend and validate the developed methodology when a multiple-injection strategy is imposed on the engine.
The paper presents the results obtained during the experimentation of a two cylinder diesel engine equipped with a common rail injection system, that was performed in the Laboratory of the Mechanical and Industrial Department of ‘ROMA TRE’ University. During the tests, a wide variation of the injection parameters settings is imposed on the engine (timing and duration) in its complete operative field.