In a two-stroke slow-speed large marine diesel engine, the combustion has not been concerned so much, since the engine has sufficient room in time and in space for combustion completion. Diesel combustion has number of various processes such as fuel injection, evaporation, mixing, ignition and combustion. In order to estimate the combustion process, both experiment and simulation were performed under various engine conditions in this research work. In the experiment, the characteristics of the rate of heat release data were discussed with systematic measurements that were carried out on assignment of the experiment design method with four parameters of the engine performance using a test engine. Here, compression ratio, nozzle hole diameter, pump plunger diameter, and scavenging pressure, were chosen as the four control parameters. As a result, the characteristics of the three important values in the rate of heat release: combustion period, peak height, and period up to the peak could be obtained, depending upon mean effective pressure, engine speed and the four control parameters. In particular, it was found that the peak in height does not change with increasing mean effective pressure over a certain level and double peaks can be seen under some fuel injecting conditions of higher load. Based on the above knowledge, the combustion process that can be induced directly from the analyzed data of the rate of heat release curve, was estimated. It was found that the combustion rate decreases when the fuel spray arrives at a certain circumferential angle, which almost corresponds to the position of the next nozzle. Also, the rate of heat release curve shows double peaks in such a case that combustion suspended period due to interference of the burned gas from the nozzle at upstream side and the fuel quantity that should be injected still remains a lot. Finally it was confirmed that the estimation of the combustion process obtained from the experiment shows the same tendency as the results obtained from the simulation with KIVA code.
Estimation of combustion process based on rate of heat release curve in a two-stroke slow-speed large marine diesel engine
Bewertung des Verbrennungsprozesses in einem langsam laufenden Zweitakt-Schiffsdieselmotor
2004
15 Seiten, 31 Bilder, 13 Quellen
Conference paper
Storage medium
English
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