Tomasz Kniaziewicz

Development of alternative ship propulsion in terms of exhaust emissions

The introduction of new emission limits for exhaust emissions of ship engines contributes to the development of new powertrain solutions. New solutions in the simplest approach concern the reduction of the concentration of sulfur in motor fuels. Typically, the aforementioned fuels have a lower value of viscosity which causes a number of supply system problems. It is becoming more and more common to use fuel cells in engine rooms of various types of marine vessels. Unlike conventional systems that use internal combustion engines, these systems have zero exhaust emissions. Hydrogen, methanol, methane and other substances may be used as a fuel in fuel cells. However, so far the best operating parameters are manifested by cells powered by hydrogen, which is associated with difficulties in obtaining and storing this fuel. Therefore, the use of turbine engines allows the obtaining of large operating and environmental advantages. The paper presents a comparison of the ecological parameters of turbine and piston engines.

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’

Ranking of Toxic Compound Concentrations As Diagnostic Parameetrs of Marine Internal Combustion Engine

Abstract Changing selected engine structure parameters, especially fuel system parameters, affects the emission of harmful compounds in the exhaust gas. Changes in harmful compound emission are frequently ambiguous, as they highly depend on parameters controlling the combustion process. An additional problem is that simple interactions are frequently accompanied with mutual influence of these parameters. Therefore, we can say about different sensitivity of diagnostic parameters to the same excitations coming from the engine structure but executed at different loading states. When the set of diagnostic parameters is numerous and the values of these parameters are similar, there is a real problem with their correct classification, frequently based on subjective assessment by the analyst. In the article, the authors propose a methodology to classify the recorded diagnostic parameters. In earlier works by the authors [4,6,7], the information capacity index method (the Hellwig method) was proposed as the measure of diagnostic parameter sensitivity. Based on this method, a rankling of diagnostic parameters can be created which divides the set of diagnostic variables into stimulators and destimulators. Novel authors’ approach to the presented problem consists in including nominants, i.e. variables with the most favourable value for the analysed aspect of the research, in the set of diagnostic variables. This normalisation of the set is believed to be helpful for making a diagnostic decision free from analyst’s arbitrariness. The zero unitarization method can also be helpful in creating diagnostic tests.

Mathematical Description of the Trajectory of Vessel Motion in Order to Determine Emission of Harmful Compounds in Exhaust Gases

The growing pressure from the society meant that pollution of the atmosphere by gases of marine engines has become one of the main problems in the protection of the marine environment recent years. Areas of ports like port city or coastal areas are exposed to the impact of pollution from the mainland as well as the considerable impact of harmful compounds contained in the exhaust gas of vessels. In order to determine the share of floating in air pollution and the prevention of the harmful effects of toxic compounds in the exhaust, it is necessary to value the knowledge of marine engines emissions of these compounds from the individual units. This is possible with knowledge of motion parameters of individuals, including their trajectory of motion, the concentrations of individual compounds for these parameters and atmospheric conditions in the region of their presence.The mathematical description of the trajectory of motion of the craft after any track (curve) as a first and essential step in modeling the total emissions of pollutants from internal combustion engines to marine main propulsion of vessels used in the balancing of the pollution is presented in this work.

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.