ERROR ANALYSIS IN INDICATED PRESSURE AND HEAT RELEASE CALCULATIONS IN DIRECT INJECTION DIESEL ENGINES

Accurate values of indicated pressure are required both to improve engine diagnostic and to validate numerical calculation. Therefore the errors in data measuring, recording and processing must be recognized and if possible minimized. Certainly this argument is not a new one. Fundamental works in this field were done by Brown, who published two papers on the accuracy of measurement using piezoelectric transducers, and by Lancaster, who discussed some problems about hardware and introduced an interactive diagnostic. This paper aims to resume and discuss the experiences of different authors giving some contributions to the problem of measuring and processing the cylinder pressure. In particular, the paper deals with some problems regarding hardware, data processing, errors in indicated mean effective pressure and heat release determination. Some suggestions are provided about an interactive diagnostic.