Problems of determining mean indicator pressure of piston combustion engines from developed indicator diagrams

The paper presents methods for processing and analysis of in-cylinder pressure course in the combustion chamber of marine engines. In literature are described determinate methods ofmean indicator pressure from closed diagrams, with are but rarely recorded than developed diagrams. There have been showed on limitations occurrence at measurements fast-changed pressures of marine diesel engines in operating conditions and measuring errors the attendants. Mean indicated pressure determined from the indicated timing or angular pressure courses in the cylinders is still a reliable diagnostic symptom. The paper presents too the results of experimental measurement of in-cylinder pressure signals, medium speed marine engines with application resistive sensor and using the photo-optical sensor of crankshaft position, and without the marker position of the crankshaft. Not always possible to altach the marker for the position of the crankshaft, and even there is no way of stopping the engine when you need to diagnose it. The top dead centre of the piston can be determined then analytically. The work developed a method of determining the mean indicated pressure of the developed indicator diagrams. Based on calculations ofmean indicator pressure made many of diagnosis of the medium speed marine diesel engines in the operating conditions.