Nauka ta progres transportu (Oct 2015)
FORMALIZATION OF DIESEL ENGINE OPERATION CONSIDERING THE EVALUATION OF VELOCITY DURING THE COMBUSTION PROCESSES
Abstract
Purpose. Under modern conditions the applying methods and design models as well as the evaluation of the operational characteristics of diesel engines do not completely take into consideration the specifics of the combustion processes. In part, such situation is characterized by the complexity of considering of varied by its nature processes that haven’t been completely investigated. In this context it is necessary to find the new methods and models which would provide relatively simple solutions through the use of integrated factors based on the analysis of parameters of diesel engines. Methodology. The proposed algorithms for the estimating of the combustion process in the form of volumetric and linear velocities is based on the well-known parameters of power and mean effective pressure and allows to compare the efficiency of their behavior in various versions of diesel engines. Findings. The author specified that the volumetric / linear velocity ratio is characterized by some strength and depends on the geometric dimensions of the cylinder-piston group. Due to the assumptions it has become possible to consider the operation of a diesel engine as a system comprising: 1) the subsystem that provides the possibility of obtaining the thermal energy; 2) the subsystem providing the thermal energy transformation; 3) the subsystem that provides the necessary diesel engine power depending on terms of combustion of air-fuel mixture. Originality. The author of the paper proposed the indices of volumetric and linear combustion velocity of air-fuel mixture in the engine cylinder, that allow to obtain the comparative value in different modifications taking into account the possible choice of optimum ratio. Practical value. The usage of indices of volumetric and linear velocities of the combustion processes in the engine cylinder combined with a mathematical model will simplify the method of diesels calculating. Parametric indices of the mentioned velocities will provide the following effective researches in diesel engine design as well as the evaluation of their loading during the operation.
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