Сhanging the lubricity of diesel fuel with vegetable oil additive

Intriduction. The environmental safety of cars with a diesel engine does not lose its relevance. In the conditions of stricter requirements for diesel fuel, the content of many substances harmful to the environment, including sulfur, is not allowed. As is known, low-sulfur fuels require the presence of additives that improve the lubricating properties of diesel fuel. Non-compliance with the requirements for lubricity significantly affects the resource of the fuel supply system of a diesel engine, primarily the Common Rail system. In order with the circumstances listed above, we hypothesized that vegetable oil can serve in small concentrations to improve the lubricating properties of fuels.Materials and methods. In our research, we conducted experiments using the standard HFRR method (highfrequency translational motion of a ball rubbing against a plate in fuel). A microscope was used to visually assess the wear spots and measure their size. Diesel fuel was taken as samples for experiments and vegetable oil was added to it as an additive in certain proportions.Discussion and conclusions. The vegetable oil additive can improve the lubricity of diesel fuel, even if it does not comply with GOST for this parameter. The experiments conducted allow us to conclude that the vegetable oil additive as a percentage of diesel fuel almost linearly reduces the diameter of the wear spot

Grinding of Titanium Alloys

X-ray spectroscopic microanalysis was used to determine the concentration of titanium on the surface of the wear spot of a silicon carbide crystal during micro-scratching and the concentration of silicon on the treated surface after grinding by a wheel of silicon carbide. The wear resistance and grinding coefficient of titanium alloys under micro-scratching with single crystals and grinding with wheels made of corundum, silicon carbide, cubic boron nitride and diamond were determined. The morphology of the treated surface and the regularities of changes in the indicators of the grinding process of titanium alloys with circles of various characteristics were studied. The features of the process of grinding titanium alloys using various lubricants and coolants are shown. The influence of the characteristics of the abrasive tool and grinding modes on low-cycle fatigue on the operation of flat and round grinding of samples made of titanium alloys VT9 and VT22 was studied. The influence of abrasive material, grinding speed, feed and sparkout during finishing on low-cycle fatigue was analyzed. Based on the research, recommendations were given for choosing a rational characteristic of the abrasive tool and processing modes.

A novel wear angle determination algorithm for wear image based on direction correlation of wear scar

A lubricant is a substance that lessens friction and wear between mechanical parts. A good quality lubricating oil is required for protecting the mechanical equipment and reducing energy consumption. Its performance index (friction coefficient) could be measured by the four-ball wear test. For the morphological analysis of testing data from the four-ball wear test, determination of wear angle is very important for measuring the wear spot diameter, validity of the four-ball wear test and recognition of abnormal wear scar. On the basis of character analysis and image processing technology, a novel wear angle determination algorithm for wear scar is presented in this article. The direction of the wear scar (wear angle) is determined based on angle transformation and grey consistency (the smallest change of grey level). Simulation results show that the algorithm has high precision, good robustness and less time consuming. The average absolute error of our method is 0.8° and the absolute error of 95% of samples is <4°. The average runtime per frame is 3.896 s in the simulation platform.

Correlation study of fuel injection strategies on engine emission and lubricating oil performance

Based on different fuel injection strategies, this paper analyzes the factors such as engine original emission smoke, exhaust temperature, soot content, wear spot diameter and kinematic viscosity. The study found that delaying injection timing, increased afterburn, engine original soot emissions, exhaust gas temperature increase, but will increase the thermal load of the parts. At the same time, the growth rate of lubricant soot and kinematic viscosity increased; The wear spot diameter at the same soot content is reduced, and the wear is reduced. In the end, the paper finally selects 1°CA BTDC as the optimal fuel injection strategy to achieve rapid aging of engine lubricating oil in order to complete the assessment of the anti-wear performance of lubricating oil.

Application of Biochar as a Filler of Polyurea Lubricants

The possibility of using plant-based biochar as a filler for polyurea greases was studied and its effect on their performance properties was evaluated. In the preparation of lubricants, group III petroleum oil and dioctiladipinate ester were used as dispersion media, and dimourea with a concentration of 20% was used as a thickener. It was found that lubricants containing 5-15 wt.% biochar, better reduce the diameter of the wear spot and are characterized by higher colloidal stability compared to samples that do not contain biochar. Additive to dispersion media 1 wt.% of the thickening polyisobutylene additive PIB 10 improves the performance properties of the lubricant.

The influence of specific lubricants on the friction and wear properties of titanium aluminum nitride + solid carbon two-layer coating investigation

The influence of three model lubricants (inactive, surface-active and chemically active) on the friction-wear characteristics of steel—steel friction pairs, steel—coating of titanium aluminum nitride and steel—two-layer coating of titanium aluminum nitride + hard carbon coating is studied. The minimum coeffi cient of friction and the minimum diameters of the wear spot were established for the combination of steel-two-layer coating of titanium aluminum nitride + hard carbon coat ing-orientant in compared media.

Nanodiamonds Particles as Additives in Lubricants

In the current work we report results of tribological testing of stable colloidal dispersions of detonation nanodiamond (DND) and polytetrafluoroethylene (PTFE) in mineral oil based greases as well as in polyalphaolefin (PAO) oil. Testing has been performed on these formula-tions using ring-on-ring, shaft/bushing and four ball test techniques. The test results demon-strated significant improvements for tribological characteristics (friction coefficient, extreme pressure failure load and diameter of wear spot) for certain formulations. A strong synergistic effect when using a combination of DND/PTFE additives was observed by a sharp decrease of friction coefficient. It was also demonstrated that using DND with smaller aggregate size (10nm versus 150nm) resulted in better lubricating performance of PAO-based composition.