Yuriy Victorovich Zablotsky ¹, Sergey Victorovich Sagin ¹

Affiliations
1 Marine power plants department of National University Odessa Maritime Academy, Odessa, UA

Abstract

Objectives: The article is aimed at discussing the results of application of marine motor fuel additives. Method: A method for improving fuel performance properties by applying fuel additives has been proposed. A 6N21L medium-speed fourstroke cycle diesel by Yanmar was used for this research. A RME25 marine fuel, viscosity of 25 sSt at 100oC and sulphur content of 2.8 w.w%, was applied. An additive containing active oxygen-bearing groups and modified with light metal salts was used as a fuel additive. Findings: Experiments were done, using three diesels of the same type, which allowed for one diesel to run on the basic fuel, and for feeding the additive-containing fuel into cylinders of two other diesels (following additional equipment of the fuel system with a flow meter and a dispenser). Specific fuel oil consumption, exit gas temperature, NOx and SOx concentration in the exit gases, and technical condition of fuel system and cylinderpiston group elements were determined in this experiment. It was shown that the use of fuel additives improves fuel efficiency of a marine diesel, in particular reduces specific fuel oil consumption by 3.5 to 5.8% subject to diesel load and additive concentration in the fuel. Improved environmental performance of the diesel, i.e. NOx reduction by 1.4 to 4.3% and SOx reduction by 15.6 to 22.9% in exit gases, was also found. It was shown that additive concentration is of optimal importance, can be determined experimentally and depends on diesel and fuel specification. Improvements: Improved technical condition of diesel cylinder-piston group and gas outlet system elements was determined as a result of visual inspection, thus reducing work labor input for diesel purging by 20 to 25%.

Keywords

Environmental Diesel Performance, Fuel Additives, Fuel Efficiency, Intensified Fuel Combustion, Marine Internal Combustion Engine, Marine Diesel Fuel, NOx and SOx Concentration in Exit Gases, Specific Fuel Oil Consumption, Thermal Diesel Factor.

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Yuriy Victorovich Zablotsky ¹, Sergii Victorovich Sagin ¹

Affiliations
1 Marine Power Plants Department, Odessa National Maritime Academy, Odessa, UA

Abstract

Background/Objectives: The effects of hydrodynamic and boundary lubrication occurring in the plunger-bushing friction pair of the high-pressure fuel injection pump in marine combustion engines have been studied. Methods: To determine thickness of the boundary lubrication layer of fuel, optical double refraction method has been suggested based on the optical anisotropy phenomenon. As an evaluation of tribotechnical characteristics of the plunger-fuel-bushing triad the electric impulse wear measuring technique has been suggested enabling to determine friction force and wear intensity. Findings: It has been proven that the fuel located in the gap between the plunger ram and the bushing performs lubricating functions. It has been shown that, owing to the elastic and damping properties and the disjoining pressure, the boundary layer of fuel helps reducing friction loss and wear of the contacting surfaces. The thickness of the fuel boundary layer affected by two-phase pressure of plane-parallel metallic surfaces has been determined. Marine fuels with viscosity value of 380…500 sSt at 40оС were used for the experiments; investigations were carried out in the temperature range of 30…60оС. It has been experimentally established that the thickness of the fuel boundary layer ranges within 4…12 micrometer, depending on operational conditions, which enables hydrodynamic and boundary (preventing direct contact between the surfaces) modes of lubrication. The ways for improving regularity of molecules in the boundary layer and for controlling its thickness have been suggested. Applications/Improvements: Liquid-crystalline properties of the boundary layers of fuel can be used in the precision pairs of high-pressure fuel injection pumps to reduce mechanical losses and to improve fuel efficiency.

Keywords

Bushing, High-pressure Fuel Injection Pump, Hydrodynamic and Boundary Lubrication, Marine Combustion Engine, Plunger Ram, Wear Intensity.

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