Keywords: marine diesel engine, stand tests, operating parameters, turbocharger, import replacement, optimum settings, noxious exhausts, alternative measurement methods, correlation of gas analyzer readings.

Type D49 marine diesel engine (V-16) featuring home-made turbochargers type ТК 35В-31 (as a part of import replacement program) have been bench-tested for optimum settings. Optimized marine diesel engines type D49 are shown as complying with IMO Tier-II and GOST 31967–2012 standards in terms of allowable noxious exhausts. Furthermore, NOx emissions have been measured with two alternative methods — electrochemical and chemiluminescent gas analyzers. Such comparative measurements allowed to formulate conditions to ensure equivalent measurement results.

Keywords: heat release curve, operating cycle, heat release curve, conditional optimization, fuel-efficient operation.

The article discusses optimization of heat release curve in type 6ДКРН 60/229 marine low-speed diesel engine so as to achieve the most fuel-efficient operation, taking account of limitation on maximum combustion pressure. Algorithm of stepwise (iterative) optimization is offered. Such algorithm is shown to be universal and applicable to solution of other multicriterion optimization problems.

Keywords: diesel engine, vibration signal, diagnostic parameter, analog-to-digital converter, digital signal processing, spectral density of power, cophased cumulation, evaluation accuracy.

The article discusses problems involved in definition of vibration signal diagnostic parameters in the course of their preparation for digital processing. Recommendations are offered concerning selection of engine diagnostic parameter and calculation of characteristics of instruments for digital registrations of vibration signals.

Keywords: liquefied hydrocarbon gas, propane-butane, hydrocarbon fuel conversion, synthetic gas, hydrogen, engine cycle work, noxious emissions.

Presented are the results of experiments that involve adding of synthetic gas to liquefied hydrocarbon gas as a fuel for motor vehicle engines. Synthetic gas may be yielded as a product of catalytic conversion of a part of main hydrocarbon fuel.The authors analyzed the influence of adding of synthetic gas, consisting of hydrogen and carbon dioxide, on heat release dynamics and gas engine working parameters. Adding of 5 % synthetic gas to regular fuel gas resulted in lower emissions of CO2 and unburned hydrocarbons as well as higher engine cycle work.

Keywords: diesel engine, petrol engine, motor oil, low-temperature sedimentation, evaluation methods, test modes.

One of the most important characteristics of modern motor oils for petrol and diesel engines is their tendency to low-temperature sedimentation, depending on engine load, speed and temperature. It should be noted, however, that existing RF standards for diesel motor oils provide no limitations concerning said characteristic. The authors analyzed known Russian and worldwide methods of motor oils tendency to low-temperature sedimentation, with a view to provide specifications for the development of Russian method of quality evaluation for diesel motor oils.

Keywords: marine power plant, liquefied natural gas (LNG), dual fuel engine, construction features, knock immunity.

The article discusses feasibility of using liquefied natural gas as a fuel for marine power plants, taking account of its better economic performance compared with liquid hydrocarbonic fuel. Brief review of existing dual fuel marine engines is provided. Also provided is evaluation of correlation between LNG composition (depending on its origin) on its methane number and knock immunity.

Keywords: marine engine, noxious emissions, gas fuel, methane number, dual fuel injector.

Planned stepwise (starting since 2016) implementation of controlled emission zones (ЕСА) by International Maritime Organization (IMO), as well as widening of the nomenclature of normalized noxious exhaust components (NOx, SOx, CO2 and PM), are drivers for further improvement of gas engine design and combustion technologies. «Yanmar Co. Ltd» developed the two types of marine gas engines: a pure gas engine and a dual fuel engine. The previous is intended to be used in a marine power plant as either auxiliary or propulsion engine, while the latter should be coupled with a propeller shaft directly. These two engines have been adapted to IMO/Tier-III NOx restriction, while concentrations of sulfur oxides (SOx) and particles (PM) in exhaust gas are negligible.
The new marine gas engines feature state-of-the-art technologies of fuel mix composition such as to prevent knocking and misfire. «Woodward L'Orange GmbH» developed and implemented innovative dual-fuel injector for high-speed gas-diesel engines, based on successive injection of fuel gas and pilot diesel fuel. The injector was tested on a high-speed single-cylinder research engine, with a view to define total injection rate as well as hole-to-hole scattering effects and shot-to-shot variation effects. Furthermore, the benefits of exploiting the maximum permissible gas pressure (up to 500 bar) of the injector are assessed and the use of natural gas (NG) enriched by hydrogen (H2) is evaluated with regard to engine performance.
The CIMAC papers have been translated into Russian by G. Melnik, PhD