Keywords: thermal cycles' efficiency.

An attempt is made to analyse thermal cycles' efficiency in order to identify optimum combinations of compression ratio and maximum combustion pressure values. The analysis is based on the assumption of so-called ideal cycles. Two combinations of cycle parameters are considered. These authors' idea is to optimise thermal cycle of high-speed diesel engine so as the pressure in cylinder at the end of the compression stroke would virtually be the same as the maximum combustion pressure.

Keywords: mathematical model of gas flow.

Based on hydraulic gas dynamics equations, a mathematical model of gas flow to the piston rings in high-speed transport diesel engine has been developed. Since precise general solution of Navier-Stokes equations faces insurmountable mathematical difficulties arising from their non-linear character, the authors substantially simplified the equations through estimation of value orders in source dependences. The problem was thus reduced to one of relatively easily solvable linear problems of modelling steady-state laminar (stratified) movement of viscose incompressible liquid in flat tube, which should facilitate the development of calculation.

Keywords: power units.

Transient heat exchange processes caused by steep increase in actuating medium temperature are least studied of all heat exchange transients. The experiments described herein have been targeted at exploration of heat exchange transients caused by steep increase in actuating medium temperature, given high temperature difference. The tests have been carried out on open-loop wind tunnel, where actuating medium was plasma-heated over the whole work range of Reynolds number. The process involves increase in flow temperature and speed by 3 times or more in short time, which results in thermal and hydraulic nonstationarity combined with gas flow acceleration. Conditions are identified under which turbulent boundary layer turns laminar.

Keywords: torque vibrations.

Presented is a new algorithm of analysis of marine diesel engine's shaft line for torque vibrations during normal operation and anticipated operational occurrences. Ways are offered to enhance the accuracy of calculations used in solutions of incompletely structured problems. The method in question is supported by newly-developed software. Examples are presented of practical analyses applied to some existing marine propulsion units.

Keywords: turbocharger test stands.

Specialists of Penza Design Office for Turbochargers faced the problem of sealing the exhaust manifolds of turbocharger test stands, and came to pneumatic sealing as a solution. Such a sealing is simple in design, and may be recommended for use in test stands featuring any diesel engines.

Keywords: water pump.

New friction pair is intended to replace currently used steel/graphite washers in order to enhance durability of water pump seal exposed to high temperature and pressure. The authors offered to use washers made of type AK4-1 aluminium alloy strengthened with micro-arc oxidation that ensures sufficient hardness of contact surface. Change to aluminium washer led to decrease in temperature in contact zone by 20%.

Keywords: exhaust valve opening and closure.

Angles of exhaust valve opening and closure can be identified by means of engine indicator diagram registered by a local diagnostics system. Nonlinear (logarithmic) representation of the initial process is used to this purpose; then characteristic segments of the yielded curve are approximated with first-degree polynomials, whereupon logic solutions are being derived. The algorithm of identification of actual exhaust valve timing is based on a formal method whereby angles between segments of the indicator curve and respective tangents are calculated. The algorithm is illustrated by a real example.

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The article presents vibroacoustic condition monitoring as new diagnostic approach based on measurement of shaft line torque vibrations. Mathematical simulation methods have been developed that enable overall diagnostics of marine engine condition based on vibroacoustic measurements. It involves simulation of inertia forces and moments of engine cylinders and the propeller that are dependent on engine cylinders' conditions. A propulsion unit is simulated with an equations set describing shaft line torque vibrations. The equations set is analytically solved with Cramer's rule. The vibroacoustic models derived can be used as a basis for development of dedicated soft- and hardware applicable to condition monitoring and diagnostics of marine engines.

Keywords: low-speed engines.

Latest development of electronic technologies, high-response solenoids and hydraulic control components enabled construction of low-speed engines featuring flexible control systems, which demonstrate numerous advantages over conventional ones. The description is focused on engine models exemplifying new technologies in question, such as (MAN B& W), UEC-Eco (MHI), and RT-flex (Wartsila NSD).

Keywords: marine diesel.

Maintenance schedule based on risk analysis can be used for the enhancement of safe ship operation. The author considers possible ways of how risks of faults in principal components of marine diesel engines could be taken into account. Values of extent of damages and marine diesel failure rates are borrowed from insurers' reports. Presented is a review of the most important guidelines on organisation of risk analysis-based schedule maintenance systems. Risk evaluation enables making comparative analyses of various engines from the viewpoint of possible damages' minimisation, and selection of suitable engine model based on allowable risk rate.

Keywords: multi-server transport networks

Such technologies can be used for timely training of specialists in server-based transportation at the crossover of such disciplines as "Internal Combustion Engines", "Applied Informatics", and "Service". Another field of application is compilation of express handbooks on state-of-art technologies covering multi-server transport networks, in order to promote newest achievements in transport-related integral symbiotic and microelectronic as applied to server-based control.

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