Marcin Zacharewicz

Alternative diagnostic method applied on marine diesel engines having limited monitoring susceptibility

The paper presents a method of technical state evaluation of working spaces of a marine diesel engine at the limited control susceptibility. The method foresees making a diagnosis of the engine’s working spaces on the basis of measurements of the exhaust gas pressure in the channels connecting engine cylinders with the turbocharger’s turbine. Diagnostic measurements are carried out at representative (comparative) steady loads depending on floating conditions. In the beginning of the article, the research objects are characterized, i.e. a Zviezda marine main engine M401 type and Detroit Diesel marine auxiliary engine DDA149TI type. Then, diagnostic measures used to identify the condition of the considered engines are defined. Moreover, selected results of diagnostic tests carried out on the engines in current operation on warships in the Polish Navy are demonstrated. The tested diagnostic classifiers confirmed that the elaborated method could be successfully applied for the engines not equipped with indicator valves.

Modelling of the operating process in a marine diesel engine

ABSTRACT The paper presents elements of a mathematical model of a marine diesel engine. The purpose of developing the model is to enable diagnostics of fuel supply and charge exchange system in a marine engine (simulation diagnostics). The authors have assumed the option allowing to modify geometric parameters of the crank-piston system, charge exchange, heat exchange and chemical composition of fuel. This option offers simulation of selected defects in an engine. The focus of the paper is both the process of model development and its implementation in an object-oriented programming language. Abbreviations: C: number of working cycles; c: specific heat; D: diameter; d: accuracy of calculations performed; i: iteration; j: value corresponding to subsequent working cycles; k: number of strokes; l: crankshaft length/air demand; m: mass; m: mass stream; n: number of cylinders; p: pressure; : heat stream; R: individual gas constant; r: length of crank arm; S: cross-section area; T: temperature; W: calorific value; w: flow velocity; V: volume; x: linear dimension; α: rotation angle; ρ: density; κ: adiabatic exponent; λ: air excess factor; μ: inflow/outflow factor; τ: time; cyl: refers to ‘cylinder’; chł: refers to ‘cooling’; ks: refers ‘combustion chamber’; max: refers to maximum value; o: refers to ‘theoretical air demand’; pal: refers to ‘fuel’; z: refers to ‘cylinder supply’; zaw: refers to ‘valves’; r: refers ‘real air demand’

Conception and Practical Application of a Measuring Device for Energetic Parameters Measurement of a Mechatronic Object

In the article assumptions of the developed non-invasive method of evaluation technical condition of selected structural elements of the ships diesel-electric set at limited monitoring susceptibility, when the engine is not equipped with indicator valves, are discussed. The method is based on simultaneous measurements of phase-to-phase voltage of the synchronous generator, exhaust gas pressures in the exhaust manifold, and vibration accelerations of some parts of the set. To the purpose of the accomplishment all measurements of energetic parameters at the same time, it turned out to be necessary to design and construct the measured quantity converter. In the paper requirements in relation to such a converter, technical project, and representative results of measurements conducted on a real object – diesel-electric set type ZE400/52 – are presented.

Problems of Mathematical Modeling of the Marine Diesel Engine Working Cycle for the Diagnostic Purposes

In the paper the first phase of a mathematical model construction of processes occurring in the cylinder during the working cycle of marine internal combustion engine is presented. The physical model of the mechanical and thermodynamic processes taking place when marine diesel engine drives a synchronous generator is described. In addition, assumptions of the mathematical model developed for marine engine diagnostics are discussed. The input parameters of the model and some simplifying assumptions have been presented. In parallel with the mathematical model, a computer program was created to facilitate carrying out the calculations. Descriptions of the mathematical model and a computer program are illustrated by means of graphs of selected parameters of combustion engine as a function of rotation angle of the crankshaft.