This article presents a theoretical analysis of the use of spiral-elliptical ducts in the atomizer of a modern fuel injector. The parameters of the injected fuel stream can be divided into quantitative and qualitative. The quantitative parameter is the injection dose amount, and the qualitative parameter is characterized by the stream of injected fuel (width, atomization, opening angle, and range). The purpose of atomizer modification is to cause additional flow turbulence, which may affect the stream parameters and improve the combustion process of the combustible mixture in a diesel engine. The spiral-elliptical ducts discussed here could be used in engines powered by vegetable fuels. The stream of such fuels has worse quality parameters than conventional fuels, due to their higher viscosity and density. The proposal to use spiral-elliptical ducts is an innovative idea for diesel engines.

Purpose: The aim of the proposed research is to investigate the hydrogen effect on the high-nickel steel surface properties changing during machining and wear with participation of lubricant-cooling environments. Design/methodology/approach: The approach of the fracture mechanics and physicalchemical methods surface properties investigation was used to formulate the conclusions. Applying of lubricant-cooling (liquid, solid, gaseous) technological environments (LCTE) has change the morphology of chips and roughness of contact 23Ni1Mo3Ti steel surfaces depending on the experimentally fixed hydrogen concentrations (4.62…12.0 ppm). It correlates with both the roughness of the treated surface and the nature of the cutting products fragmentation: the maximum concentration of hydrogen - in the chips coincides with the minimum size of its defragmentation and reduction of the surface roughness. For nitrogen and oxygen, a similar relationship is traced poorly. Findings: On the basis of the fracture mechanics approaches it is confirmed, that in the conditions of the application of hydrogen containing (as chemical composition) (up to 12 ppm) and hydrogen accumulated (in nano container) (up to 600 ppm) LCTE, hydrogen enters the near crack initiation contact zone before fracture and taking part in changing structural material fracture mechanisms, improves its mashinning processes. Research limitations/implications: The results obtained on laboratory specimens should be tested during machining of real details made from high-nickel steel. Practical implications: The created technological approaches can be used in practice evaluation of mechanical properties and residual of modern gas turbine parts. Originality/value: It was shown, that hydrogen containing (in chemical composition) and hydrogen accumulated (in nano container) LCTE permits the hydrogen to enter in the near crack initiation contact zone before fracture and taking part in changing structural material fracture mechanisms.

The article concerns the possibility of using a fuel pretreatment system in modern compression ignition CI engines, the main task of which is the reduction of toxic emissions in the form of exhaust gases. This fuel pretreatment system consists of a catalytic reactor used in common rail (CR), and a modified fuel atomizer into spiral‒elliptical channels covered with catalytic material. In the system presented here, platinum was the catalyst. The catalyst’s task is to cause the dehydrogenation reaction of paraffin hydrocarbons contained in the fuel to create an olefin form, with the release of a free hydrogen molecule. In the literature, the methods of using catalysts in the exhaust systems of engines, or in combustion chambers, injection pumps, or fuel injectors, are known. However, the use of a catalytic reactor in the CR system in a high-pressure fuel atomizer rail is an innovative project proposed by the authors. Conditions in the high-pressure CR system are favorable for the catalyst’s operation. In addition, the spiral‒elliptical channels made on the inoperative part of the fuel atomizer needle increase the flow turbulence and contact surface for the catalyst.

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