Article Title

The model graph analyzing of generating units fuel-using systems by methods of automatic control theory

Journal: Journal of Transsib Railway Studies V.2(18), 2014
Journal thematic sections: Transport power engineering
Pages: 47-55
Authors: V. R. Vedruchenko
udk: 621.436-7:62-50
Article reference
Vedruchenko V. R. , Krajnov V. V. The model graph analyzing of generating units fuel-using systems by methods of automatic control theory Izvestiia Transsiba – The Trans-Siberian Bulletin, 2014, no. 2(18), pp. 47 – 55.

Abstract

The subject of the study is the fuel utilization system of a diesel power plant as a diesel locomo-tive or other vehicle main lead, which is a complex technical system consisting of actual diesel in-ternal combustion engine, fuel lines and low pressure fuel processing and high pressure line includ-ing various elements of liquid fuels consumption dosing and control. The aim of our study was to analyze the system functioning, to determine the dynamic proper-ties and the nature of changes in the internal parameters of the system as a whole. To achieve the goal the system analysis methods were used. The processes of complex technical system operation were interpreted by means of the continuous linear stationary deterministic model of the list of others. For this particular model the body of mathematics developed on the basis of linear differential equations with constant coefficients is the most complete one. The chosen mathematical model was presented by us in the first stage in the form of a finite graph as a subgraph of obtained earlier generalized model which had both methodological and theoretical foundation. In accordance with the methodology of the systematic approach the graph model of the diesel power plant fuel utilization system operation was described in relation to major significant factors affecting the system parameters transformation dynamics. Given the complexity of the of fuel ignition and combustion mechanism located in the diesel engine cylinder, the use of the techniques of the modern automated control theory is adopted for numerical processes simulation with the system described in terms of the said theory. The criteria of efficiency, mechanical loads and thermal loads levels were chosen as the fuel utilization system internal state variables. Taking into account the Pareto principle the most important efficiency criterion components were chosen for the analysis; and the system of differential equations of the efficiency dynamics in the form of three balance equations was created. The factual description of the included equations allowed us to derive preliminary qualitative conclusions about the dynamic properties of the internal criteria: controllability, observability and stability of the fuel utilization system. The differential equations system parameters linearizing procedure and the introduction of small deviations allowed us to obtain the dynamic mathematical model of the fuel and air transfor-mation in the diesel engine heat cylinder. As the result of transformations we have obtained the equations presented in the form of the matrices, which allowed us to conclude that the process of the fuel and air transformation in the cylinder is controllable, the system is asymptotically stable, and the process is stochastic with the presence of perturbing parameters influenced by the engine's variable modes of operation. The further research areas have been suggested, and the practical results have been predicted: the creation of optimal (in terms of efficiency) control system with the technical solution in the form of the optimal controller (in relation to fuel consumption).