Determining an in-cylinder pressure curve representative of the evolution of the pressure within a cylinder

摘要

An in-cylinder pressure curve representative of the evolution of the pressure within a cylinder of a multi-cylinder internal combustion engine is determined by setting a timeframe in which the engine is functioning such that the pressure in at least two cylinders is sampled at consecutive time periods within the timeframe in order to acquire partial in cylinder pressure curves for each cylinder. The partial in cylinder pressure curves are used to reconstruct a whole in cylinder pressure curve. Each sampling period may be adjusted separately from each other on the base of one or more engine operating parameters, the adjustment may be the period width, opening or closing and the parameters may be the engine speed or engine load. The partial in cylinder pressure curves may be representative of different stages of an engine cycle. The sampling periods may be chosen such that the at least two partial in cylinder pressue curves comprise of an overlapping portion and a non overlapping portion. The method may be cyclically repeatable during the engine functioning. A computer program may be used to carry a computer code to perform this method.