Abstrakt

In the cylinders of a marine diesel engine, self-ignition occurs in very shortly time after the fuel injection into the combustion chamber. Therefore, the paper present was to develop a model of diesel fuel spray for the early stage of fuel spray for in marine diesel engine. There were taken into consideration the main aspects technical such as nozzle diameter of marine engine injector and backpressure in combustion chamber. In this work, laboratory experimental studies were carried out in order to determined parameters of fuel spray in early stage of injection in marine diesel engine. Optical measuring Mie scattering technique was used to record the fuel injection process. The working space was a constant volume chamber. The backpressure parameters in the constant volume chamber were the same as during the operation of the marine diesel engine. On the based on the experimental studies and important Hiroyasu and Arai models of fuel spray presented in literature was proposed new model of fuel spray parameters for marine diesel injector. In this work, proposed new model of the two main parameters described fuel spray evolution: new model of spray tip penetration and spray cone angle. New model propagation of fuel spray tip penetration in time was included the influenced of nozzle diameter and backpressure. The proposed model has a lower error, about 15%-34%, than the model of Hiroyasu and Arai. Moreover a new model of the evolution over time of the spray cone angle is developed. In the future research of fuel spray process must be taken influence of the fuel temperature. Diesel fuel has a different density and viscosity in dependence of fuel temperature. Therefore are predicted of the expansion about influence of fuel temperature, new model of fuel spray for a marine diesel engine. The main limitations occuring in the research are is it not possible to carry out the research while real operation marine diesel engine. Experimental test were carried out for a real fuel injector of a marine diesel engine. Design parameters and fuel injection parameters were selected on the basis of the actual one. In the literature, spray cone angle is defined as constant parameter for the specific preliminary data. A new model for the early stage of fuel spray of spray cone angle propagation in time has beed proposed. The early stage of fuel spray is especially important, because in this time comes in there to fuel self-ignition.

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